Merge branch 'tracing-v28-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'tracing-v28-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (131 commits)
  tracing/fastboot: improve help text
  tracing/stacktrace: improve help text
  tracing/fastboot: fix initcalls disposition in bootgraph.pl
  tracing/fastboot: fix bootgraph.pl initcall name regexp
  tracing/fastboot: fix issues and improve output of bootgraph.pl
  tracepoints: synchronize unregister static inline
  tracepoints: tracepoint_synchronize_unregister()
  ftrace: make ftrace_test_p6nop disassembler-friendly
  markers: fix synchronize marker unregister static inline
  tracing/fastboot: add better resolution to initcall debug/tracing
  trace: add build-time check to avoid overrunning hex buffer
  ftrace: fix hex output mode of ftrace
  tracing/fastboot: fix initcalls disposition in bootgraph.pl
  tracing/fastboot: fix printk format typo in boot tracer
  ftrace: return an error when setting a nonexistent tracer
  ftrace: make some tracers reentrant
  ring-buffer: make reentrant
  ring-buffer: move page indexes into page headers
  tracing/fastboot: only trace non-module initcalls
  ftrace: move pc counter in irqtrace
  ...

Manually fix conflicts:
 - init/main.c: initcall tracing
 - kernel/module.c: verbose level vs tracepoints
 - scripts/bootgraph.pl: fallout from cherry-picking commits.

Documentation/markers.txt

@@ -50,10 +50,12 @@ Connecting a function (probe) to a marker is done by providing a probe (function
 to call) for the specific marker through marker_probe_register() and can be
 activated by calling marker_arm(). Marker deactivation can be done by calling
 marker_disarm() as many times as marker_arm() has been called. Removing a probe
-is done through marker_probe_unregister(); it will disarm the probe and make
-sure there is no caller left using the probe when it returns. Probe removal is
-preempt-safe because preemption is disabled around the probe call. See the
-"Probe example" section below for a sample probe module.
+is done through marker_probe_unregister(); it will disarm the probe.
+marker_synchronize_unregister() must be called before the end of the module exit
+function to make sure there is no caller left using the probe. This, and the
+fact that preemption is disabled around the probe call, make sure that probe
+removal and module unload are safe. See the "Probe example" section below for a
+sample probe module.
 
 The marker mechanism supports inserting multiple instances of the same marker.
 Markers can be put in inline functions, inlined static functions, and

Documentation/tracepoints.txt

@@ -0,0 +1,101 @@
+	             Using the Linux Kernel Tracepoints
+
+			    Mathieu Desnoyers
+
+
+This document introduces Linux Kernel Tracepoints and their use. It provides
+examples of how to insert tracepoints in the kernel and connect probe functions
+to them and provides some examples of probe functions.
+
+
+* Purpose of tracepoints
+
+A tracepoint placed in code provides a hook to call a function (probe) that you
+can provide at runtime. A tracepoint can be "on" (a probe is connected to it) or
+"off" (no probe is attached). When a tracepoint is "off" it has no effect,
+except for adding a tiny time penalty (checking a condition for a branch) and
+space penalty (adding a few bytes for the function call at the end of the
+instrumented function and adds a data structure in a separate section).  When a
+tracepoint is "on", the function you provide is called each time the tracepoint
+is executed, in the execution context of the caller. When the function provided
+ends its execution, it returns to the caller (continuing from the tracepoint
+site).
+
+You can put tracepoints at important locations in the code. They are
+lightweight hooks that can pass an arbitrary number of parameters,
+which prototypes are described in a tracepoint declaration placed in a header
+file.
+
+They can be used for tracing and performance accounting.
+
+
+* Usage
+
+Two elements are required for tracepoints :
+
+- A tracepoint definition, placed in a header file.
+- The tracepoint statement, in C code.
+
+In order to use tracepoints, you should include linux/tracepoint.h.
+
+In include/trace/subsys.h :
+
+#include <linux/tracepoint.h>
+
+DEFINE_TRACE(subsys_eventname,
+	TPPTOTO(int firstarg, struct task_struct *p),
+	TPARGS(firstarg, p));
+
+In subsys/file.c (where the tracing statement must be added) :
+
+#include <trace/subsys.h>
+
+void somefct(void)
+{
+	...
+	trace_subsys_eventname(arg, task);
+	...
+}
+
+Where :
+- subsys_eventname is an identifier unique to your event
+    - subsys is the name of your subsystem.
+    - eventname is the name of the event to trace.
+- TPPTOTO(int firstarg, struct task_struct *p) is the prototype of the function
+  called by this tracepoint.
+- TPARGS(firstarg, p) are the parameters names, same as found in the prototype.
+
+Connecting a function (probe) to a tracepoint is done by providing a probe
+(function to call) for the specific tracepoint through
+register_trace_subsys_eventname().  Removing a probe is done through
+unregister_trace_subsys_eventname(); it will remove the probe sure there is no
+caller left using the probe when it returns. Probe removal is preempt-safe
+because preemption is disabled around the probe call. See the "Probe example"
+section below for a sample probe module.
+
+The tracepoint mechanism supports inserting multiple instances of the same
+tracepoint, but a single definition must be made of a given tracepoint name over
+all the kernel to make sure no type conflict will occur. Name mangling of the
+tracepoints is done using the prototypes to make sure typing is correct.
+Verification of probe type correctness is done at the registration site by the
+compiler. Tracepoints can be put in inline functions, inlined static functions,
+and unrolled loops as well as regular functions.
+
+The naming scheme "subsys_event" is suggested here as a convention intended
+to limit collisions. Tracepoint names are global to the kernel: they are
+considered as being the same whether they are in the core kernel image or in
+modules.
+
+
+* Probe / tracepoint example
+
+See the example provided in samples/tracepoints/src
+
+Compile them with your kernel.
+
+Run, as root :
+modprobe tracepoint-example (insmod order is not important)
+modprobe tracepoint-probe-example
+cat /proc/tracepoint-example (returns an expected error)
+rmmod tracepoint-example tracepoint-probe-example
+dmesg

Documentation/tracers/mmiotrace.txt

@@ -36,7 +36,7 @@ $ mount -t debugfs debugfs /debug
 $ echo mmiotrace > /debug/tracing/current_tracer
 $ cat /debug/tracing/trace_pipe > mydump.txt &
 Start X or whatever.
-$ echo "X is up" > /debug/tracing/marker
+$ echo "X is up" > /debug/tracing/trace_marker
 $ echo none > /debug/tracing/current_tracer
 Check for lost events.
 
@@ -59,9 +59,8 @@ The 'cat' process should stay running (sleeping) in the background.
 Load the driver you want to trace and use it. Mmiotrace will only catch MMIO
 accesses to areas that are ioremapped while mmiotrace is active.
 
-[Unimplemented feature:]
 During tracing you can place comments (markers) into the trace by
-$ echo "X is up" > /debug/tracing/marker
+$ echo "X is up" > /debug/tracing/trace_marker
 This makes it easier to see which part of the (huge) trace corresponds to
 which action. It is recommended to place descriptive markers about what you
 do.

arch/powerpc/platforms/cell/spufs/sputrace.c

@@ -232,6 +232,7 @@ static void __exit sputrace_exit(void)
 
 	remove_proc_entry("sputrace", NULL);
 	kfree(sputrace_log);
+	marker_synchronize_unregister();
 }
 
 module_init(sputrace_init);

arch/x86/Kconfig

@@ -26,6 +26,7 @@ config X86
 	select HAVE_KPROBES
 	select ARCH_WANT_OPTIONAL_GPIOLIB
 	select HAVE_KRETPROBES
+	select HAVE_FTRACE_MCOUNT_RECORD
 	select HAVE_DYNAMIC_FTRACE
 	select HAVE_FTRACE
 	select HAVE_KVM if ((X86_32 && !X86_VOYAGER && !X86_VISWS && !X86_NUMAQ) || X86_64)

arch/x86/kernel/cpu/perfctr-watchdog.c

@@ -17,6 +17,8 @@
 #include <linux/bitops.h>
 #include <linux/smp.h>
 #include <linux/nmi.h>
+#include <linux/kprobes.h>
+
 #include <asm/apic.h>
 #include <asm/intel_arch_perfmon.h>
 
@@ -336,7 +338,8 @@ static void single_msr_unreserve(void)
 	release_perfctr_nmi(wd_ops->perfctr);
 }
 
-static void single_msr_rearm(struct nmi_watchdog_ctlblk *wd, unsigned nmi_hz)
+static void __kprobes
+single_msr_rearm(struct nmi_watchdog_ctlblk *wd, unsigned nmi_hz)
 {
 	/* start the cycle over again */
 	write_watchdog_counter(wd->perfctr_msr, NULL, nmi_hz);
@@ -401,7 +404,7 @@ static int setup_p6_watchdog(unsigned nmi_hz)
 	return 1;
 }
 
-static void p6_rearm(struct nmi_watchdog_ctlblk *wd, unsigned nmi_hz)
+static void __kprobes p6_rearm(struct nmi_watchdog_ctlblk *wd, unsigned nmi_hz)
 {
 	/*
 	 * P6 based Pentium M need to re-unmask
@@ -605,7 +608,7 @@ static void p4_unreserve(void)
 	release_perfctr_nmi(MSR_P4_IQ_PERFCTR0);
 }
 
-static void p4_rearm(struct nmi_watchdog_ctlblk *wd, unsigned nmi_hz)
+static void __kprobes p4_rearm(struct nmi_watchdog_ctlblk *wd, unsigned nmi_hz)
 {
 	unsigned dummy;
 	/*
@@ -784,7 +787,7 @@ unsigned lapic_adjust_nmi_hz(unsigned hz)
 	return hz;
 }
 
-int lapic_wd_event(unsigned nmi_hz)
+int __kprobes lapic_wd_event(unsigned nmi_hz)
 {
 	struct nmi_watchdog_ctlblk *wd = &__get_cpu_var(nmi_watchdog_ctlblk);
 	u64 ctr;

arch/x86/kernel/entry_32.S

@@ -1153,20 +1153,6 @@ ENDPROC(xen_failsafe_callback)
 #ifdef CONFIG_DYNAMIC_FTRACE
 
 ENTRY(mcount)
-	pushl %eax
-	pushl %ecx
-	pushl %edx
-	movl 0xc(%esp), %eax
-	subl $MCOUNT_INSN_SIZE, %eax
-
-.globl mcount_call
-mcount_call:
-	call ftrace_stub
-
-	popl %edx
-	popl %ecx
-	popl %eax
-
 	ret
 END(mcount)
 

arch/x86/kernel/entry_64.S

@@ -64,32 +64,6 @@
 #ifdef CONFIG_FTRACE
 #ifdef CONFIG_DYNAMIC_FTRACE
 ENTRY(mcount)
-
-	subq $0x38, %rsp
-	movq %rax, (%rsp)
-	movq %rcx, 8(%rsp)
-	movq %rdx, 16(%rsp)
-	movq %rsi, 24(%rsp)
-	movq %rdi, 32(%rsp)
-	movq %r8, 40(%rsp)
-	movq %r9, 48(%rsp)
-
-	movq 0x38(%rsp), %rdi
-	subq $MCOUNT_INSN_SIZE, %rdi
-
-.globl mcount_call
-mcount_call:
-	call ftrace_stub
-
-	movq 48(%rsp), %r9
-	movq 40(%rsp), %r8
-	movq 32(%rsp), %rdi
-	movq 24(%rsp), %rsi
-	movq 16(%rsp), %rdx
-	movq 8(%rsp), %rcx
-	movq (%rsp), %rax
-	addq $0x38, %rsp
-
 	retq
 END(mcount)
 

arch/x86/kernel/ftrace.c

@@ -11,17 +11,18 @@
 
 #include <linux/spinlock.h>
 #include <linux/hardirq.h>
+#include <linux/uaccess.h>
 #include <linux/ftrace.h>
 #include <linux/percpu.h>
 #include <linux/init.h>
 #include <linux/list.h>
 
-#include <asm/alternative.h>
 #include <asm/ftrace.h>
+#include <asm/nops.h>
 
 
 /* Long is fine, even if it is only 4 bytes ;-) */
-static long *ftrace_nop;
+static unsigned long *ftrace_nop;
 
 union ftrace_code_union {
 	char code[MCOUNT_INSN_SIZE];
@@ -60,11 +61,7 @@ notrace int
 ftrace_modify_code(unsigned long ip, unsigned char *old_code,
 		   unsigned char *new_code)
 {
-	unsigned replaced;
-	unsigned old = *(unsigned *)old_code; /* 4 bytes */
-	unsigned new = *(unsigned *)new_code; /* 4 bytes */
-	unsigned char newch = new_code[4];
-	int faulted = 0;
+	unsigned char replaced[MCOUNT_INSN_SIZE];
 
 	/*
 	 * Note: Due to modules and __init, code can
@@ -72,29 +69,20 @@ ftrace_modify_code(unsigned long ip, unsigned char *old_code,
 	 *  as well as code changing.
 	 *
 	 * No real locking needed, this code is run through
-	 * kstop_machine.
+	 * kstop_machine, or before SMP starts.
 	 */
-	asm volatile (
-		"1: lock\n"
-		"   cmpxchg %3, (%2)\n"
-		"   jnz 2f\n"
-		"   movb %b4, 4(%2)\n"
-		"2:\n"
-		".section .fixup, \"ax\"\n"
-		"3:	movl $1, %0\n"
-		"	jmp 2b\n"
-		".previous\n"
-		_ASM_EXTABLE(1b, 3b)
-		: "=r"(faulted), "=a"(replaced)
-		: "r"(ip), "r"(new), "c"(newch),
-		  "0"(faulted), "a"(old)
-		: "memory");
-	sync_core();
+	if (__copy_from_user_inatomic(replaced, (char __user *)ip, MCOUNT_INSN_SIZE))
+		return 1;
+
+	if (memcmp(replaced, old_code, MCOUNT_INSN_SIZE) != 0)
+		return 2;
 
-	if (replaced != old && replaced != new)
-		faulted = 2;
+	WARN_ON_ONCE(__copy_to_user_inatomic((char __user *)ip, new_code,
+				    MCOUNT_INSN_SIZE));
 
-	return faulted;
+	sync_core();
+
+	return 0;
 }
 
 notrace int ftrace_update_ftrace_func(ftrace_func_t func)
@@ -112,30 +100,76 @@ notrace int ftrace_update_ftrace_func(ftrace_func_t func)
 
 notrace int ftrace_mcount_set(unsigned long *data)
 {
-	unsigned long ip = (long)(&mcount_call);
-	unsigned long *addr = data;
-	unsigned char old[MCOUNT_INSN_SIZE], *new;
-
-	/*
-	 * Replace the mcount stub with a pointer to the
-	 * ip recorder function.
-	 */
-	memcpy(old, &mcount_call, MCOUNT_INSN_SIZE);
-	new = ftrace_call_replace(ip, *addr);
-	*addr = ftrace_modify_code(ip, old, new);
-
+	/* mcount is initialized as a nop */
+	*data = 0;
 	return 0;
 }
 
 int __init ftrace_dyn_arch_init(void *data)
 {
-	const unsigned char *const *noptable = find_nop_table();
-
-	/* This is running in kstop_machine */
-
-	ftrace_mcount_set(data);
+	extern const unsigned char ftrace_test_p6nop[];
+	extern const unsigned char ftrace_test_nop5[];
+	extern const unsigned char ftrace_test_jmp[];
+	int faulted = 0;
 
-	ftrace_nop = (unsigned long *)noptable[MCOUNT_INSN_SIZE];
+	/*
+	 * There is no good nop for all x86 archs.
+	 * We will default to using the P6_NOP5, but first we
+	 * will test to make sure that the nop will actually
+	 * work on this CPU. If it faults, we will then
+	 * go to a lesser efficient 5 byte nop. If that fails
+	 * we then just use a jmp as our nop. This isn't the most
+	 * efficient nop, but we can not use a multi part nop
+	 * since we would then risk being preempted in the middle
+	 * of that nop, and if we enabled tracing then, it might
+	 * cause a system crash.
+	 *
+	 * TODO: check the cpuid to determine the best nop.
+	 */
+	asm volatile (
+		"jmp ftrace_test_jmp\n"
+		/* This code needs to stay around */
+		".section .text, \"ax\"\n"
+		"ftrace_test_jmp:"
+		"jmp ftrace_test_p6nop\n"
+		"nop\n"
+		"nop\n"
+		"nop\n"  /* 2 byte jmp + 3 bytes */
+		"ftrace_test_p6nop:"
+		P6_NOP5
+		"jmp 1f\n"
+		"ftrace_test_nop5:"
+		".byte 0x66,0x66,0x66,0x66,0x90\n"
+		"jmp 1f\n"
+		".previous\n"
+		"1:"
+		".section .fixup, \"ax\"\n"
+		"2:	movl $1, %0\n"
+		"	jmp ftrace_test_nop5\n"
+		"3:	movl $2, %0\n"
+		"	jmp 1b\n"
+		".previous\n"
+		_ASM_EXTABLE(ftrace_test_p6nop, 2b)
+		_ASM_EXTABLE(ftrace_test_nop5, 3b)
+		: "=r"(faulted) : "0" (faulted));
+
+	switch (faulted) {
+	case 0:
+		pr_info("ftrace: converting mcount calls to 0f 1f 44 00 00\n");
+		ftrace_nop = (unsigned long *)ftrace_test_p6nop;
+		break;
+	case 1:
+		pr_info("ftrace: converting mcount calls to 66 66 66 66 90\n");
+		ftrace_nop = (unsigned long *)ftrace_test_nop5;
+		break;
+	case 2:
+		pr_info("ftrace: converting mcount calls to jmp . + 5\n");
+		ftrace_nop = (unsigned long *)ftrace_test_jmp;
+		break;
+	}
+
+	/* The return code is retured via data */
+	*(unsigned long *)data = 0;
 
 	return 0;
 }

arch/x86/mm/mmio-mod.c

@@ -56,13 +56,6 @@ struct remap_trace {
 static DEFINE_PER_CPU(struct trap_reason, pf_reason);
 static DEFINE_PER_CPU(struct mmiotrace_rw, cpu_trace);
 
-#if 0 /* XXX: no way gather this info anymore */
-/* Access to this is not per-cpu. */
-static DEFINE_PER_CPU(atomic_t, dropped);
-#endif
-
-static struct dentry *marker_file;
-
 static DEFINE_MUTEX(mmiotrace_mutex);
 static DEFINE_SPINLOCK(trace_lock);
 static atomic_t mmiotrace_enabled;
@@ -75,7 +68,7 @@ static LIST_HEAD(trace_list);		/* struct remap_trace */
  *   and trace_lock.
  * - Routines depending on is_enabled() must take trace_lock.
  * - trace_list users must hold trace_lock.
- * - is_enabled() guarantees that mmio_trace_record is allowed.
+ * - is_enabled() guarantees that mmio_trace_{rw,mapping} are allowed.
  * - pre/post callbacks assume the effect of is_enabled() being true.
  */
 
@@ -97,44 +90,6 @@ static bool is_enabled(void)
 	return atomic_read(&mmiotrace_enabled);
 }
 
-#if 0 /* XXX: needs rewrite */
-/*
- * Write callback for the debugfs entry:
- * Read a marker and write it to the mmio trace log
- */
-static ssize_t write_marker(struct file *file, const char __user *buffer,
-						size_t count, loff_t *ppos)
-{
-	char *event = NULL;
-	struct mm_io_header *headp;
-	ssize_t len = (count > 65535) ? 65535 : count;
-
-	event = kzalloc(sizeof(*headp) + len, GFP_KERNEL);
-	if (!event)
-		return -ENOMEM;
-
-	headp = (struct mm_io_header *)event;
-	headp->type = MMIO_MAGIC | (MMIO_MARKER << MMIO_OPCODE_SHIFT);
-	headp->data_len = len;
-
-	if (copy_from_user(event + sizeof(*headp), buffer, len)) {
-		kfree(event);
-		return -EFAULT;
-	}
-
-	spin_lock_irq(&trace_lock);
-#if 0 /* XXX: convert this to use tracing */
-	if (is_enabled())
-		relay_write(chan, event, sizeof(*headp) + len);
-	else
-#endif
-		len = -EINVAL;
-	spin_unlock_irq(&trace_lock);
-	kfree(event);
-	return len;
-}
-#endif
-
 static void print_pte(unsigned long address)
 {
 	unsigned int level;
@@ -307,8 +262,10 @@ static void ioremap_trace_core(resource_size_t offset, unsigned long size,
 	map.map_id = trace->id;
 
 	spin_lock_irq(&trace_lock);
-	if (!is_enabled())
+	if (!is_enabled()) {
+		kfree(trace);
 		goto not_enabled;
+	}
 
 	mmio_trace_mapping(&map);
 	list_add_tail(&trace->list, &trace_list);
@@ -377,6 +334,23 @@ void mmiotrace_iounmap(volatile void __iomem *addr)
 		iounmap_trace_core(addr);
 }
 
+int mmiotrace_printk(const char *fmt, ...)
+{
+	int ret = 0;
+	va_list args;
+	unsigned long flags;
+	va_start(args, fmt);
+
+	spin_lock_irqsave(&trace_lock, flags);
+	if (is_enabled())
+		ret = mmio_trace_printk(fmt, args);
+	spin_unlock_irqrestore(&trace_lock, flags);
+
+	va_end(args);
+	return ret;
+}
+EXPORT_SYMBOL(mmiotrace_printk);
+
 static void clear_trace_list(void)
 {
 	struct remap_trace *trace;
@@ -462,26 +436,12 @@ static void leave_uniprocessor(void)
 }
 #endif
 
-#if 0 /* XXX: out of order */
-static struct file_operations fops_marker = {
-	.owner =	THIS_MODULE,
-	.write =	write_marker
-};
-#endif
-
 void enable_mmiotrace(void)
 {
 	mutex_lock(&mmiotrace_mutex);
 	if (is_enabled())
 		goto out;
 
-#if 0 /* XXX: tracing does not support text entries */
-	marker_file = debugfs_create_file("marker", 0660, dir, NULL,
-								&fops_marker);
-	if (!marker_file)
-		pr_err(NAME "marker file creation failed.\n");
-#endif
-
 	if (nommiotrace)
 		pr_info(NAME "MMIO tracing disabled.\n");
 	enter_uniprocessor();
@@ -506,11 +466,6 @@ void disable_mmiotrace(void)
 
 	clear_trace_list(); /* guarantees: no more kmmio callbacks */
 	leave_uniprocessor();
-	if (marker_file) {
-		debugfs_remove(marker_file);
-		marker_file = NULL;
-	}
-
 	pr_info(NAME "disabled.\n");
 out:
 	mutex_unlock(&mmiotrace_mutex);

arch/x86/mm/pf_in.c

@@ -79,25 +79,34 @@ static unsigned int mw32[] = { 0xC7 };
 static unsigned int mw64[] = { 0x89, 0x8B };
 #endif /* not __i386__ */
 
-static int skip_prefix(unsigned char *addr, int *shorted, int *enlarged,
-								int *rexr)
+struct prefix_bits {
+	unsigned shorted:1;
+	unsigned enlarged:1;
+	unsigned rexr:1;
+	unsigned rex:1;
+};
+
+static int skip_prefix(unsigned char *addr, struct prefix_bits *prf)
 {
 	int i;
 	unsigned char *p = addr;
-	*shorted = 0;
-	*enlarged = 0;
-	*rexr = 0;
+	prf->shorted = 0;
+	prf->enlarged = 0;
+	prf->rexr = 0;
+	prf->rex = 0;
 
 restart:
 	for (i = 0; i < ARRAY_SIZE(prefix_codes); i++) {
 		if (*p == prefix_codes[i]) {
 			if (*p == 0x66)
-				*shorted = 1;
+				prf->shorted = 1;
 #ifdef __amd64__
 			if ((*p & 0xf8) == 0x48)
-				*enlarged = 1;
+				prf->enlarged = 1;
 			if ((*p & 0xf4) == 0x44)
-				*rexr = 1;
+				prf->rexr = 1;
+			if ((*p & 0xf0) == 0x40)
+				prf->rex = 1;
 #endif
 			p++;
 			goto restart;
@@ -135,12 +144,12 @@ enum reason_type get_ins_type(unsigned long ins_addr)
 {
 	unsigned int opcode;
 	unsigned char *p;
-	int shorted, enlarged, rexr;
+	struct prefix_bits prf;
 	int i;
 	enum reason_type rv = OTHERS;
 
 	p = (unsigned char *)ins_addr;
-	p += skip_prefix(p, &shorted, &enlarged, &rexr);
+	p += skip_prefix(p, &prf);
 	p += get_opcode(p, &opcode);
 
 	CHECK_OP_TYPE(opcode, reg_rop, REG_READ);
@@ -156,10 +165,11 @@ static unsigned int get_ins_reg_width(unsigned long ins_addr)
 {
 	unsigned int opcode;
 	unsigned char *p;
-	int i, shorted, enlarged, rexr;
+	struct prefix_bits prf;
+	int i;
 
 	p = (unsigned char *)ins_addr;
-	p += skip_prefix(p, &shorted, &enlarged, &rexr);
+	p += skip_prefix(p, &prf);
 	p += get_opcode(p, &opcode);
 
 	for (i = 0; i < ARRAY_SIZE(rw8); i++)
@@ -168,7 +178,7 @@ static unsigned int get_ins_reg_width(unsigned long ins_addr)
 
 	for (i = 0; i < ARRAY_SIZE(rw32); i++)
 		if (rw32[i] == opcode)
-			return (shorted ? 2 : (enlarged ? 8 : 4));
+			return prf.shorted ? 2 : (prf.enlarged ? 8 : 4);
 
 	printk(KERN_ERR "mmiotrace: Unknown opcode 0x%02x\n", opcode);
 	return 0;
@@ -178,10 +188,11 @@ unsigned int get_ins_mem_width(unsigned long ins_addr)
 {
 	unsigned int opcode;
 	unsigned char *p;
-	int i, shorted, enlarged, rexr;
+	struct prefix_bits prf;
+	int i;
 
 	p = (unsigned char *)ins_addr;
-	p += skip_prefix(p, &shorted, &enlarged, &rexr);
+	p += skip_prefix(p, &prf);
 	p += get_opcode(p, &opcode);
 
 	for (i = 0; i < ARRAY_SIZE(mw8); i++)
@@ -194,11 +205,11 @@ unsigned int get_ins_mem_width(unsigned long ins_addr)
 
 	for (i = 0; i < ARRAY_SIZE(mw32); i++)
 		if (mw32[i] == opcode)
-			return shorted ? 2 : 4;
+			return prf.shorted ? 2 : 4;
 
 	for (i = 0; i < ARRAY_SIZE(mw64); i++)
 		if (mw64[i] == opcode)
-			return shorted ? 2 : (enlarged ? 8 : 4);
+			return prf.shorted ? 2 : (prf.enlarged ? 8 : 4);
 
 	printk(KERN_ERR "mmiotrace: Unknown opcode 0x%02x\n", opcode);
 	return 0;
@@ -238,7 +249,7 @@ enum {
 #endif
 };
 
-static unsigned char *get_reg_w8(int no, struct pt_regs *regs)
+static unsigned char *get_reg_w8(int no, int rex, struct pt_regs *regs)
 {
 	unsigned char *rv = NULL;
 
@@ -255,18 +266,6 @@ static unsigned char *get_reg_w8(int no, struct pt_regs *regs)
 	case arg_DL:
 		rv = (unsigned char *)&regs->dx;
 		break;
-	case arg_AH:
-		rv = 1 + (unsigned char *)&regs->ax;
-		break;
-	case arg_BH:
-		rv = 1 + (unsigned char *)&regs->bx;
-		break;
-	case arg_CH:
-		rv = 1 + (unsigned char *)&regs->cx;
-		break;
-	case arg_DH:
-		rv = 1 + (unsigned char *)&regs->dx;
-		break;
 #ifdef __amd64__
 	case arg_R8:
 		rv = (unsigned char *)&regs->r8;
@@ -294,9 +293,55 @@ static unsigned char *get_reg_w8(int no, struct pt_regs *regs)
 		break;
 #endif
 	default:
-		printk(KERN_ERR "mmiotrace: Error reg no# %d\n", no);
 		break;
 	}
+
+	if (rv)
+		return rv;
+
+	if (rex) {
+		/*
+		 * If REX prefix exists, access low bytes of SI etc.
+		 * instead of AH etc.
+		 */
+		switch (no) {
+		case arg_SI:
+			rv = (unsigned char *)&regs->si;
+			break;
+		case arg_DI:
+			rv = (unsigned char *)&regs->di;
+			break;
+		case arg_BP:
+			rv = (unsigned char *)&regs->bp;
+			break;
+		case arg_SP:
+			rv = (unsigned char *)&regs->sp;
+			break;
+		default:
+			break;
+		}
+	} else {
+		switch (no) {
+		case arg_AH:
+			rv = 1 + (unsigned char *)&regs->ax;
+			break;
+		case arg_BH:
+			rv = 1 + (unsigned char *)&regs->bx;
+			break;
+		case arg_CH:
+			rv = 1 + (unsigned char *)&regs->cx;
+			break;
+		case arg_DH:
+			rv = 1 + (unsigned char *)&regs->dx;
+			break;
+		default:
+			break;
+		}
+	}
+
+	if (!rv)
+		printk(KERN_ERR "mmiotrace: Error reg no# %d\n", no);
+
 	return rv;
 }
 
@@ -368,11 +413,12 @@ unsigned long get_ins_reg_val(unsigned long ins_addr, struct pt_regs *regs)
 	unsigned char mod_rm;
 	int reg;
 	unsigned char *p;
-	int i, shorted, enlarged, rexr;
+	struct prefix_bits prf;
+	int i;
 	unsigned long rv;
 
 	p = (unsigned char *)ins_addr;
-	p += skip_prefix(p, &shorted, &enlarged, &rexr);
+	p += skip_prefix(p, &prf);
 	p += get_opcode(p, &opcode);
 	for (i = 0; i < ARRAY_SIZE(reg_rop); i++)
 		if (reg_rop[i] == opcode) {
@@ -392,10 +438,10 @@ unsigned long get_ins_reg_val(unsigned long ins_addr, struct pt_regs *regs)
 
 do_work:
 	mod_rm = *p;
-	reg = ((mod_rm >> 3) & 0x7) | (rexr << 3);
+	reg = ((mod_rm >> 3) & 0x7) | (prf.rexr << 3);
 	switch (get_ins_reg_width(ins_addr)) {
 	case 1:
-		return *get_reg_w8(reg, regs);
+		return *get_reg_w8(reg, prf.rex, regs);
 
 	case 2:
 		return *(unsigned short *)get_reg_w32(reg, regs);
@@ -422,11 +468,12 @@ unsigned long get_ins_imm_val(unsigned long ins_addr)
 	unsigned char mod_rm;
 	unsigned char mod;
 	unsigned char *p;
-	int i, shorted, enlarged, rexr;
+	struct prefix_bits prf;
+	int i;
 	unsigned long rv;
 
 	p = (unsigned char *)ins_addr;
-	p += skip_prefix(p, &shorted, &enlarged, &rexr);
+	p += skip_prefix(p, &prf);
 	p += get_opcode(p, &opcode);
 	for (i = 0; i < ARRAY_SIZE(imm_wop); i++)
 		if (imm_wop[i] == opcode) {

arch/x86/mm/testmmiotrace.c

@@ -3,6 +3,7 @@
  */
 #include <linux/module.h>
 #include <linux/io.h>
+#include <linux/mmiotrace.h>
 
 #define MODULE_NAME "testmmiotrace"
 
@@ -13,6 +14,7 @@ MODULE_PARM_DESC(mmio_address, "Start address of the mapping of 16 kB.");
 static void do_write_test(void __iomem *p)
 {
 	unsigned int i;
+	mmiotrace_printk("Write test.\n");
 	for (i = 0; i < 256; i++)
 		iowrite8(i, p + i);
 	for (i = 1024; i < (5 * 1024); i += 2)
@@ -24,6 +26,7 @@ static void do_write_test(void __iomem *p)
 static void do_read_test(void __iomem *p)
 {
 	unsigned int i;
+	mmiotrace_printk("Read test.\n");
 	for (i = 0; i < 256; i++)
 		ioread8(p + i);
 	for (i = 1024; i < (5 * 1024); i += 2)
@@ -39,6 +42,7 @@ static void do_test(void)
 		pr_err(MODULE_NAME ": could not ioremap, aborting.\n");
 		return;
 	}
+	mmiotrace_printk("ioremap returned %p.\n", p);
 	do_write_test(p);
 	do_read_test(p);
 	iounmap(p);

include/asm-generic/vmlinux.lds.h

@@ -37,6 +37,13 @@
 #define MEM_DISCARD(sec) *(.mem##sec)
 #endif
 
+#ifdef CONFIG_FTRACE_MCOUNT_RECORD
+#define MCOUNT_REC()	VMLINUX_SYMBOL(__start_mcount_loc) = .; \
+			*(__mcount_loc)				\
+			VMLINUX_SYMBOL(__stop_mcount_loc) = .;
+#else
+#define MCOUNT_REC()
+#endif
 
 /* .data section */
 #define DATA_DATA							\
@@ -52,7 +59,10 @@
 	. = ALIGN(8);							\
 	VMLINUX_SYMBOL(__start___markers) = .;				\
 	*(__markers)							\
-	VMLINUX_SYMBOL(__stop___markers) = .;
+	VMLINUX_SYMBOL(__stop___markers) = .;				\
+	VMLINUX_SYMBOL(__start___tracepoints) = .;			\
+	*(__tracepoints)						\
+	VMLINUX_SYMBOL(__stop___tracepoints) = .;
 
 #define RO_DATA(align)							\
 	. = ALIGN((align));						\
@@ -61,6 +71,7 @@
 		*(.rodata) *(.rodata.*)					\
 		*(__vermagic)		/* Kernel version magic */	\
 		*(__markers_strings)	/* Markers: strings */		\
+		*(__tracepoints_strings)/* Tracepoints: strings */	\
 	}								\
 									\
 	.rodata1          : AT(ADDR(.rodata1) - LOAD_OFFSET) {		\
@@ -188,6 +199,7 @@
 	/* __*init sections */						\
 	__init_rodata : AT(ADDR(__init_rodata) - LOAD_OFFSET) {		\
 		*(.ref.rodata)						\
+		MCOUNT_REC()						\
 		DEV_KEEP(init.rodata)					\
 		DEV_KEEP(exit.rodata)					\
 		CPU_KEEP(init.rodata)					\

include/asm-x86/ftrace.h

@@ -7,6 +7,16 @@
 
 #ifndef __ASSEMBLY__
 extern void mcount(void);
+
+static inline unsigned long ftrace_call_adjust(unsigned long addr)
+{
+	/*
+	 * call mcount is "e8 <4 byte offset>"
+	 * The addr points to the 4 byte offset and the caller of this
+	 * function wants the pointer to e8. Simply subtract one.
+	 */
+	return addr - 1;
+}
 #endif
 
 #endif /* CONFIG_FTRACE */

include/linux/compiler.h

@@ -44,6 +44,8 @@ extern void __chk_io_ptr(const volatile void __iomem *);
 # error Sorry, your compiler is too old/not recognized.
 #endif
 
+#define notrace __attribute__((no_instrument_function))
+
 /* Intel compiler defines __GNUC__. So we will overwrite implementations
  * coming from above header files here
  */

include/linux/ftrace.h

@@ -1,10 +1,14 @@
 #ifndef _LINUX_FTRACE_H
 #define _LINUX_FTRACE_H
 
-#ifdef CONFIG_FTRACE
-
 #include <linux/linkage.h>
 #include <linux/fs.h>
+#include <linux/ktime.h>
+#include <linux/init.h>
+#include <linux/types.h>
+#include <linux/kallsyms.h>
+
+#ifdef CONFIG_FTRACE
 
 extern int ftrace_enabled;
 extern int
@@ -36,6 +40,7 @@ extern void ftrace_stub(unsigned long a0, unsigned long a1);
 # define register_ftrace_function(ops) do { } while (0)
 # define unregister_ftrace_function(ops) do { } while (0)
 # define clear_ftrace_function(ops) do { } while (0)
+static inline void ftrace_kill_atomic(void) { }
 #endif /* CONFIG_FTRACE */
 
 #ifdef CONFIG_DYNAMIC_FTRACE
@@ -76,8 +81,10 @@ extern void mcount_call(void);
 
 extern int skip_trace(unsigned long ip);
 
-void ftrace_disable_daemon(void);
-void ftrace_enable_daemon(void);
+extern void ftrace_release(void *start, unsigned long size);
+
+extern void ftrace_disable_daemon(void);
+extern void ftrace_enable_daemon(void);
 
 #else
 # define skip_trace(ip)				({ 0; })
@@ -85,6 +92,7 @@ void ftrace_enable_daemon(void);
 # define ftrace_set_filter(buf, len, reset)	do { } while (0)
 # define ftrace_disable_daemon()		do { } while (0)
 # define ftrace_enable_daemon()			do { } while (0)
+static inline void ftrace_release(void *start, unsigned long size) { }
 #endif /* CONFIG_DYNAMIC_FTRACE */
 
 /* totally disable ftrace - can not re-enable after this */
@@ -98,9 +106,11 @@ static inline void tracer_disable(void)
 #endif
 }
 
-/* Ftrace disable/restore without lock. Some synchronization mechanism
+/*
+ * Ftrace disable/restore without lock. Some synchronization mechanism
  * must be used to prevent ftrace_enabled to be changed between
- * disable/restore. */
+ * disable/restore.
+ */
 static inline int __ftrace_enabled_save(void)
 {
 #ifdef CONFIG_FTRACE
@@ -157,9 +167,71 @@ static inline void __ftrace_enabled_restore(int enabled)
 #ifdef CONFIG_TRACING
 extern void
 ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3);
+
+/**
+ * ftrace_printk - printf formatting in the ftrace buffer
+ * @fmt: the printf format for printing
+ *
+ * Note: __ftrace_printk is an internal function for ftrace_printk and
+ *       the @ip is passed in via the ftrace_printk macro.
+ *
+ * This function allows a kernel developer to debug fast path sections
+ * that printk is not appropriate for. By scattering in various
+ * printk like tracing in the code, a developer can quickly see
+ * where problems are occurring.
+ *
+ * This is intended as a debugging tool for the developer only.
+ * Please refrain from leaving ftrace_printks scattered around in
+ * your code.
+ */
+# define ftrace_printk(fmt...) __ftrace_printk(_THIS_IP_, fmt)
+extern int
+__ftrace_printk(unsigned long ip, const char *fmt, ...)
+	__attribute__ ((format (printf, 2, 3)));
+extern void ftrace_dump(void);
 #else
 static inline void
 ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3) { }
+static inline int
+ftrace_printk(const char *fmt, ...) __attribute__ ((format (printf, 1, 0)));
+
+static inline int
+ftrace_printk(const char *fmt, ...)
+{
+	return 0;
+}
+static inline void ftrace_dump(void) { }
 #endif
 
+#ifdef CONFIG_FTRACE_MCOUNT_RECORD
+extern void ftrace_init(void);
+extern void ftrace_init_module(unsigned long *start, unsigned long *end);
+#else
+static inline void ftrace_init(void) { }
+static inline void
+ftrace_init_module(unsigned long *start, unsigned long *end) { }
+#endif
+
+
+struct boot_trace {
+	pid_t			caller;
+	char			func[KSYM_NAME_LEN];
+	int			result;
+	unsigned long long	duration;		/* usecs */
+	ktime_t			calltime;
+	ktime_t			rettime;
+};
+
+#ifdef CONFIG_BOOT_TRACER
+extern void trace_boot(struct boot_trace *it, initcall_t fn);
+extern void start_boot_trace(void);
+extern void stop_boot_trace(void);
+#else
+static inline void trace_boot(struct boot_trace *it, initcall_t fn) { }
+static inline void start_boot_trace(void) { }
+static inline void stop_boot_trace(void) { }
+#endif
+
+
+
 #endif /* _LINUX_FTRACE_H */

include/linux/init.h

@@ -40,7 +40,7 @@
 
 /* These are for everybody (although not all archs will actually
    discard it in modules) */
-#define __init		__section(.init.text) __cold
+#define __init		__section(.init.text) __cold notrace
 #define __initdata	__section(.init.data)
 #define __initconst	__section(.init.rodata)
 #define __exitdata	__section(.exit.data)

include/linux/kernel.h

@@ -496,4 +496,9 @@ struct sysinfo {
 #define NUMA_BUILD 0
 #endif
 
+/* Rebuild everything on CONFIG_FTRACE_MCOUNT_RECORD */
+#ifdef CONFIG_FTRACE_MCOUNT_RECORD
+# define REBUILD_DUE_TO_FTRACE_MCOUNT_RECORD
+#endif
+
 #endif

include/linux/kprobes.h

@@ -29,6 +29,7 @@
  *		<jkenisto@us.ibm.com>  and Prasanna S Panchamukhi
  *		<prasanna@in.ibm.com> added function-return probes.
  */
+#include <linux/linkage.h>
 #include <linux/list.h>
 #include <linux/notifier.h>
 #include <linux/smp.h>
@@ -47,7 +48,7 @@
 #define KPROBE_HIT_SSDONE	0x00000008
 
 /* Attach to insert probes on any functions which should be ignored*/
-#define __kprobes	__attribute__((__section__(".kprobes.text")))
+#define __kprobes	__attribute__((__section__(".kprobes.text"))) notrace
 
 struct kprobe;
 struct pt_regs;
@@ -256,7 +257,7 @@ void recycle_rp_inst(struct kretprobe_instance *ri, struct hlist_head *head);
 
 #else /* CONFIG_KPROBES */
 
-#define __kprobes	/**/
+#define __kprobes	notrace
 struct jprobe;
 struct kretprobe;
 

include/linux/linkage.h

@@ -4,8 +4,6 @@
 #include <linux/compiler.h>
 #include <asm/linkage.h>
 
-#define notrace __attribute__((no_instrument_function))
-
 #ifdef __cplusplus
 #define CPP_ASMLINKAGE extern "C"
 #else

include/linux/marker.h

@@ -160,4 +160,11 @@ extern int marker_probe_unregister_private_data(marker_probe_func *probe,
 extern void *marker_get_private_data(const char *name, marker_probe_func *probe,
 	int num);
 
+/*
+ * marker_synchronize_unregister must be called between the last marker probe
+ * unregistration and the end of module exit to make sure there is no caller
+ * executing a probe when it is freed.
+ */
+#define marker_synchronize_unregister() synchronize_sched()
+
 #endif

include/linux/mmiotrace.h

@@ -34,11 +34,15 @@ extern void unregister_kmmio_probe(struct kmmio_probe *p);
 /* Called from page fault handler. */
 extern int kmmio_handler(struct pt_regs *regs, unsigned long addr);
 
-/* Called from ioremap.c */
 #ifdef CONFIG_MMIOTRACE
+/* Called from ioremap.c */
 extern void mmiotrace_ioremap(resource_size_t offset, unsigned long size,
 							void __iomem *addr);
 extern void mmiotrace_iounmap(volatile void __iomem *addr);
+
+/* For anyone to insert markers. Remember trailing newline. */
+extern int mmiotrace_printk(const char *fmt, ...)
+				__attribute__ ((format (printf, 1, 2)));
 #else
 static inline void mmiotrace_ioremap(resource_size_t offset,
 					unsigned long size, void __iomem *addr)
@@ -48,15 +52,22 @@ static inline void mmiotrace_ioremap(resource_size_t offset,
 static inline void mmiotrace_iounmap(volatile void __iomem *addr)
 {
 }
-#endif /* CONFIG_MMIOTRACE_HOOKS */
+
+static inline int mmiotrace_printk(const char *fmt, ...)
+				__attribute__ ((format (printf, 1, 0)));
+
+static inline int mmiotrace_printk(const char *fmt, ...)
+{
+	return 0;
+}
+#endif /* CONFIG_MMIOTRACE */
 
 enum mm_io_opcode {
 	MMIO_READ = 0x1,     /* struct mmiotrace_rw */
 	MMIO_WRITE = 0x2,    /* struct mmiotrace_rw */
 	MMIO_PROBE = 0x3,    /* struct mmiotrace_map */
 	MMIO_UNPROBE = 0x4,  /* struct mmiotrace_map */
-	MMIO_MARKER = 0x5,   /* raw char data */
-	MMIO_UNKNOWN_OP = 0x6, /* struct mmiotrace_rw */
+	MMIO_UNKNOWN_OP = 0x5, /* struct mmiotrace_rw */
 };
 
 struct mmiotrace_rw {
@@ -81,5 +92,6 @@ extern void enable_mmiotrace(void);
 extern void disable_mmiotrace(void);
 extern void mmio_trace_rw(struct mmiotrace_rw *rw);
 extern void mmio_trace_mapping(struct mmiotrace_map *map);
+extern int mmio_trace_printk(const char *fmt, va_list args);
 
 #endif /* MMIOTRACE_H */

include/linux/module.h

@@ -16,6 +16,7 @@
 #include <linux/kobject.h>
 #include <linux/moduleparam.h>
 #include <linux/marker.h>
+#include <linux/tracepoint.h>
 #include <asm/local.h>
 
 #include <asm/module.h>
@@ -331,6 +332,10 @@ struct module
 	struct marker *markers;
 	unsigned int num_markers;
 #endif
+#ifdef CONFIG_TRACEPOINTS
+	struct tracepoint *tracepoints;
+	unsigned int num_tracepoints;
+#endif
 
 #ifdef CONFIG_MODULE_UNLOAD
 	/* What modules depend on me? */
@@ -453,6 +458,9 @@ extern void print_modules(void);
 
 extern void module_update_markers(void);
 
+extern void module_update_tracepoints(void);
+extern int module_get_iter_tracepoints(struct tracepoint_iter *iter);
+
 #else /* !CONFIG_MODULES... */
 #define EXPORT_SYMBOL(sym)
 #define EXPORT_SYMBOL_GPL(sym)
@@ -557,6 +565,15 @@ static inline void module_update_markers(void)
 {
 }
 
+static inline void module_update_tracepoints(void)
+{
+}
+
+static inline int module_get_iter_tracepoints(struct tracepoint_iter *iter)
+{
+	return 0;
+}
+
 #endif /* CONFIG_MODULES */
 
 struct device_driver;

include/linux/ring_buffer.h

@@ -0,0 +1,127 @@
+#ifndef _LINUX_RING_BUFFER_H
+#define _LINUX_RING_BUFFER_H
+
+#include <linux/mm.h>
+#include <linux/seq_file.h>
+
+struct ring_buffer;
+struct ring_buffer_iter;
+
+/*
+ * Don't reference this struct directly, use functions below.
+ */
+struct ring_buffer_event {
+	u32		type:2, len:3, time_delta:27;
+	u32		array[];
+};
+
+/**
+ * enum ring_buffer_type - internal ring buffer types
+ *
+ * @RINGBUF_TYPE_PADDING:	Left over page padding
+ *				 array is ignored
+ *				 size is variable depending on how much
+ *				  padding is needed
+ *
+ * @RINGBUF_TYPE_TIME_EXTEND:	Extend the time delta
+ *				 array[0] = time delta (28 .. 59)
+ *				 size = 8 bytes
+ *
+ * @RINGBUF_TYPE_TIME_STAMP:	Sync time stamp with external clock
+ *				 array[0] = tv_nsec
+ *				 array[1] = tv_sec
+ *				 size = 16 bytes
+ *
+ * @RINGBUF_TYPE_DATA:		Data record
+ *				 If len is zero:
+ *				  array[0] holds the actual length
+ *				  array[1..(length+3)/4-1] holds data
+ *				 else
+ *				  length = len << 2
+ *				  array[0..(length+3)/4] holds data
+ */
+enum ring_buffer_type {
+	RINGBUF_TYPE_PADDING,
+	RINGBUF_TYPE_TIME_EXTEND,
+	/* FIXME: RINGBUF_TYPE_TIME_STAMP not implemented */
+	RINGBUF_TYPE_TIME_STAMP,
+	RINGBUF_TYPE_DATA,
+};
+
+unsigned ring_buffer_event_length(struct ring_buffer_event *event);
+void *ring_buffer_event_data(struct ring_buffer_event *event);
+
+/**
+ * ring_buffer_event_time_delta - return the delta timestamp of the event
+ * @event: the event to get the delta timestamp of
+ *
+ * The delta timestamp is the 27 bit timestamp since the last event.
+ */
+static inline unsigned
+ring_buffer_event_time_delta(struct ring_buffer_event *event)
+{
+	return event->time_delta;
+}
+
+/*
+ * size is in bytes for each per CPU buffer.
+ */
+struct ring_buffer *
+ring_buffer_alloc(unsigned long size, unsigned flags);
+void ring_buffer_free(struct ring_buffer *buffer);
+
+int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size);
+
+struct ring_buffer_event *
+ring_buffer_lock_reserve(struct ring_buffer *buffer,
+			 unsigned long length,
+			 unsigned long *flags);
+int ring_buffer_unlock_commit(struct ring_buffer *buffer,
+			      struct ring_buffer_event *event,
+			      unsigned long flags);
+int ring_buffer_write(struct ring_buffer *buffer,
+		      unsigned long length, void *data);
+
+struct ring_buffer_event *
+ring_buffer_peek(struct ring_buffer *buffer, int cpu, u64 *ts);
+struct ring_buffer_event *
+ring_buffer_consume(struct ring_buffer *buffer, int cpu, u64 *ts);
+
+struct ring_buffer_iter *
+ring_buffer_read_start(struct ring_buffer *buffer, int cpu);
+void ring_buffer_read_finish(struct ring_buffer_iter *iter);
+
+struct ring_buffer_event *
+ring_buffer_iter_peek(struct ring_buffer_iter *iter, u64 *ts);
+struct ring_buffer_event *
+ring_buffer_read(struct ring_buffer_iter *iter, u64 *ts);
+void ring_buffer_iter_reset(struct ring_buffer_iter *iter);
+int ring_buffer_iter_empty(struct ring_buffer_iter *iter);
+
+unsigned long ring_buffer_size(struct ring_buffer *buffer);
+
+void ring_buffer_reset_cpu(struct ring_buffer *buffer, int cpu);
+void ring_buffer_reset(struct ring_buffer *buffer);
+
+int ring_buffer_swap_cpu(struct ring_buffer *buffer_a,
+			 struct ring_buffer *buffer_b, int cpu);
+
+int ring_buffer_empty(struct ring_buffer *buffer);
+int ring_buffer_empty_cpu(struct ring_buffer *buffer, int cpu);
+
+void ring_buffer_record_disable(struct ring_buffer *buffer);
+void ring_buffer_record_enable(struct ring_buffer *buffer);
+void ring_buffer_record_disable_cpu(struct ring_buffer *buffer, int cpu);
+void ring_buffer_record_enable_cpu(struct ring_buffer *buffer, int cpu);
+
+unsigned long ring_buffer_entries(struct ring_buffer *buffer);
+unsigned long ring_buffer_overruns(struct ring_buffer *buffer);
+
+u64 ring_buffer_time_stamp(int cpu);
+void ring_buffer_normalize_time_stamp(int cpu, u64 *ts);
+
+enum ring_buffer_flags {
+	RB_FL_OVERWRITE		= 1 << 0,
+};
+
+#endif /* _LINUX_RING_BUFFER_H */

include/linux/tracepoint.h

@@ -0,0 +1,137 @@
+#ifndef _LINUX_TRACEPOINT_H
+#define _LINUX_TRACEPOINT_H
+
+/*
+ * Kernel Tracepoint API.
+ *
+ * See Documentation/tracepoint.txt.
+ *
+ * (C) Copyright 2008 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
+ *
+ * Heavily inspired from the Linux Kernel Markers.
+ *
+ * This file is released under the GPLv2.
+ * See the file COPYING for more details.
+ */
+
+#include <linux/types.h>
+#include <linux/rcupdate.h>
+
+struct module;
+struct tracepoint;
+
+struct tracepoint {
+	const char *name;		/* Tracepoint name */
+	int state;			/* State. */
+	void **funcs;
+} __attribute__((aligned(8)));
+
+
+#define TPPROTO(args...)	args
+#define TPARGS(args...)		args
+
+#ifdef CONFIG_TRACEPOINTS
+
+/*
+ * it_func[0] is never NULL because there is at least one element in the array
+ * when the array itself is non NULL.
+ */
+#define __DO_TRACE(tp, proto, args)					\
+	do {								\
+		void **it_func;						\
+									\
+		rcu_read_lock_sched();					\
+		it_func = rcu_dereference((tp)->funcs);			\
+		if (it_func) {						\
+			do {						\
+				((void(*)(proto))(*it_func))(args);	\
+			} while (*(++it_func));				\
+		}							\
+		rcu_read_unlock_sched();				\
+	} while (0)
+
+/*
+ * Make sure the alignment of the structure in the __tracepoints section will
+ * not add unwanted padding between the beginning of the section and the
+ * structure. Force alignment to the same alignment as the section start.
+ */
+#define DEFINE_TRACE(name, proto, args)					\
+	static inline void trace_##name(proto)				\
+	{								\
+		static const char __tpstrtab_##name[]			\
+		__attribute__((section("__tracepoints_strings")))	\
+		= #name ":" #proto;					\
+		static struct tracepoint __tracepoint_##name		\
+		__attribute__((section("__tracepoints"), aligned(8))) =	\
+		{ __tpstrtab_##name, 0, NULL };				\
+		if (unlikely(__tracepoint_##name.state))		\
+			__DO_TRACE(&__tracepoint_##name,		\
+				TPPROTO(proto), TPARGS(args));		\
+	}								\
+	static inline int register_trace_##name(void (*probe)(proto))	\
+	{								\
+		return tracepoint_probe_register(#name ":" #proto,	\
+			(void *)probe);					\
+	}								\
+	static inline void unregister_trace_##name(void (*probe)(proto))\
+	{								\
+		tracepoint_probe_unregister(#name ":" #proto,		\
+			(void *)probe);					\
+	}
+
+extern void tracepoint_update_probe_range(struct tracepoint *begin,
+	struct tracepoint *end);
+
+#else /* !CONFIG_TRACEPOINTS */
+#define DEFINE_TRACE(name, proto, args)			\
+	static inline void _do_trace_##name(struct tracepoint *tp, proto) \
+	{ }								\
+	static inline void trace_##name(proto)				\
+	{ }								\
+	static inline int register_trace_##name(void (*probe)(proto))	\
+	{								\
+		return -ENOSYS;						\
+	}								\
+	static inline void unregister_trace_##name(void (*probe)(proto))\
+	{ }
+
+static inline void tracepoint_update_probe_range(struct tracepoint *begin,
+	struct tracepoint *end)
+{ }
+#endif /* CONFIG_TRACEPOINTS */
+
+/*
+ * Connect a probe to a tracepoint.
+ * Internal API, should not be used directly.
+ */
+extern int tracepoint_probe_register(const char *name, void *probe);
+
+/*
+ * Disconnect a probe from a tracepoint.
+ * Internal API, should not be used directly.
+ */
+extern int tracepoint_probe_unregister(const char *name, void *probe);
+
+struct tracepoint_iter {
+	struct module *module;
+	struct tracepoint *tracepoint;
+};
+
+extern void tracepoint_iter_start(struct tracepoint_iter *iter);
+extern void tracepoint_iter_next(struct tracepoint_iter *iter);
+extern void tracepoint_iter_stop(struct tracepoint_iter *iter);
+extern void tracepoint_iter_reset(struct tracepoint_iter *iter);
+extern int tracepoint_get_iter_range(struct tracepoint **tracepoint,
+	struct tracepoint *begin, struct tracepoint *end);
+
+/*
+ * tracepoint_synchronize_unregister must be called between the last tracepoint
+ * probe unregistration and the end of module exit to make sure there is no
+ * caller executing a probe when it is freed.
+ */
+static inline void tracepoint_synchronize_unregister(void)
+{
+	synchronize_sched();
+}
+
+#endif

include/trace/sched.h

@@ -0,0 +1,56 @@
+#ifndef _TRACE_SCHED_H
+#define _TRACE_SCHED_H
+
+#include <linux/sched.h>
+#include <linux/tracepoint.h>
+
+DEFINE_TRACE(sched_kthread_stop,
+	TPPROTO(struct task_struct *t),
+		TPARGS(t));
+
+DEFINE_TRACE(sched_kthread_stop_ret,
+	TPPROTO(int ret),
+		TPARGS(ret));
+
+DEFINE_TRACE(sched_wait_task,
+	TPPROTO(struct rq *rq, struct task_struct *p),
+		TPARGS(rq, p));
+
+DEFINE_TRACE(sched_wakeup,
+	TPPROTO(struct rq *rq, struct task_struct *p),
+		TPARGS(rq, p));
+
+DEFINE_TRACE(sched_wakeup_new,
+	TPPROTO(struct rq *rq, struct task_struct *p),
+		TPARGS(rq, p));
+
+DEFINE_TRACE(sched_switch,
+	TPPROTO(struct rq *rq, struct task_struct *prev,
+		struct task_struct *next),
+		TPARGS(rq, prev, next));
+
+DEFINE_TRACE(sched_migrate_task,
+	TPPROTO(struct rq *rq, struct task_struct *p, int dest_cpu),
+		TPARGS(rq, p, dest_cpu));
+
+DEFINE_TRACE(sched_process_free,
+	TPPROTO(struct task_struct *p),
+		TPARGS(p));
+
+DEFINE_TRACE(sched_process_exit,
+	TPPROTO(struct task_struct *p),
+		TPARGS(p));
+
+DEFINE_TRACE(sched_process_wait,
+	TPPROTO(struct pid *pid),
+		TPARGS(pid));
+
+DEFINE_TRACE(sched_process_fork,
+	TPPROTO(struct task_struct *parent, struct task_struct *child),
+		TPARGS(parent, child));
+
+DEFINE_TRACE(sched_signal_send,
+	TPPROTO(int sig, struct task_struct *p),
+		TPARGS(sig, p));
+
+#endif

init/Kconfig

@@ -786,6 +786,13 @@ config PROFILING
 	  Say Y here to enable the extended profiling support mechanisms used
 	  by profilers such as OProfile.
 
+#
+# Place an empty function call at each tracepoint site. Can be
+# dynamically changed for a probe function.
+#
+config TRACEPOINTS
+	bool
+
 config MARKERS
 	bool "Activate markers"
 	help

init/main.c

@@ -61,6 +61,7 @@
 #include <linux/sched.h>
 #include <linux/signal.h>
 #include <linux/idr.h>
+#include <linux/ftrace.h>
 
 #include <asm/io.h>
 #include <asm/bugs.h>
@@ -689,6 +690,8 @@ asmlinkage void __init start_kernel(void)
 
 	acpi_early_init(); /* before LAPIC and SMP init */
 
+	ftrace_init();
+
 	/* Do the rest non-__init'ed, we're now alive */
 	rest_init();
 }
@@ -705,30 +708,31 @@ __setup("initcall_debug", initcall_debug_setup);
 int do_one_initcall(initcall_t fn)
 {
 	int count = preempt_count();
-	ktime_t t0, t1, delta;
+	ktime_t delta;
 	char msgbuf[64];
-	int result;
+	struct boot_trace it;
 
 	if (initcall_debug) {
-		printk("calling  %pF @ %i\n", fn, task_pid_nr(current));
-		t0 = ktime_get();
+		it.caller = task_pid_nr(current);
+		printk("calling  %pF @ %i\n", fn, it.caller);
+		it.calltime = ktime_get();
 	}
 
-	result = fn();
+	it.result = fn();
 
 	if (initcall_debug) {
-		t1 = ktime_get();
-		delta = ktime_sub(t1, t0);
-
-		printk("initcall %pF returned %d after %Ld msecs\n",
-			fn, result,
-			(unsigned long long) delta.tv64 >> 20);
+		it.rettime = ktime_get();
+		delta = ktime_sub(it.rettime, it.calltime);
+		it.duration = (unsigned long long) delta.tv64 >> 10;
+		printk("initcall %pF returned %d after %Ld usecs\n", fn,
+			it.result, it.duration);
+		trace_boot(&it, fn);
 	}
 
 	msgbuf[0] = 0;
 
-	if (result && result != -ENODEV && initcall_debug)
-		sprintf(msgbuf, "error code %d ", result);
+	if (it.result && it.result != -ENODEV && initcall_debug)
+		sprintf(msgbuf, "error code %d ", it.result);
 
 	if (preempt_count() != count) {
 		strlcat(msgbuf, "preemption imbalance ", sizeof(msgbuf));
@@ -742,7 +746,7 @@ int do_one_initcall(initcall_t fn)
 		printk("initcall %pF returned with %s\n", fn, msgbuf);
 	}
 
-	return result;
+	return it.result;
 }
 
 
@@ -857,6 +861,7 @@ static int __init kernel_init(void * unused)
 	smp_prepare_cpus(setup_max_cpus);
 
 	do_pre_smp_initcalls();
+	start_boot_trace();
 
 	smp_init();
 	sched_init_smp();
@@ -883,6 +888,7 @@ static int __init kernel_init(void * unused)
 	 * we're essentially up and running. Get rid of the
 	 * initmem segments and start the user-mode stuff..
 	 */
+	stop_boot_trace();
 	init_post();
 	return 0;
 }

kernel/Makefile

@@ -85,6 +85,7 @@ obj-$(CONFIG_SYSCTL) += utsname_sysctl.o
 obj-$(CONFIG_TASK_DELAY_ACCT) += delayacct.o
 obj-$(CONFIG_TASKSTATS) += taskstats.o tsacct.o
 obj-$(CONFIG_MARKERS) += marker.o
+obj-$(CONFIG_TRACEPOINTS) += tracepoint.o
 obj-$(CONFIG_LATENCYTOP) += latencytop.o
 obj-$(CONFIG_HAVE_GENERIC_DMA_COHERENT) += dma-coherent.o
 obj-$(CONFIG_FTRACE) += trace/

kernel/exit.c

@@ -47,6 +47,7 @@
 #include <linux/blkdev.h>
 #include <linux/task_io_accounting_ops.h>
 #include <linux/tracehook.h>
+#include <trace/sched.h>
 
 #include <asm/uaccess.h>
 #include <asm/unistd.h>
@@ -146,7 +147,10 @@ static void __exit_signal(struct task_struct *tsk)
 
 static void delayed_put_task_struct(struct rcu_head *rhp)
 {
-	put_task_struct(container_of(rhp, struct task_struct, rcu));
+	struct task_struct *tsk = container_of(rhp, struct task_struct, rcu);
+
+	trace_sched_process_free(tsk);
+	put_task_struct(tsk);
 }
 
 
@@ -1070,6 +1074,8 @@ NORET_TYPE void do_exit(long code)
 
 	if (group_dead)
 		acct_process();
+	trace_sched_process_exit(tsk);
+
 	exit_sem(tsk);
 	exit_files(tsk);
 	exit_fs(tsk);
@@ -1675,6 +1681,8 @@ static long do_wait(enum pid_type type, struct pid *pid, int options,
 	struct task_struct *tsk;
 	int retval;
 
+	trace_sched_process_wait(pid);
+
 	add_wait_queue(&current->signal->wait_chldexit,&wait);
 repeat:
 	/*

kernel/fork.c

@@ -58,6 +58,7 @@
 #include <linux/tty.h>
 #include <linux/proc_fs.h>
 #include <linux/blkdev.h>
+#include <trace/sched.h>
 
 #include <asm/pgtable.h>
 #include <asm/pgalloc.h>
@@ -1372,6 +1373,8 @@ long do_fork(unsigned long clone_flags,
 	if (!IS_ERR(p)) {
 		struct completion vfork;
 
+		trace_sched_process_fork(current, p);
+
 		nr = task_pid_vnr(p);
 
 		if (clone_flags & CLONE_PARENT_SETTID)

kernel/kthread.c

@@ -13,6 +13,7 @@
 #include <linux/file.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
+#include <trace/sched.h>
 
 #define KTHREAD_NICE_LEVEL (-5)
 
@@ -205,6 +206,8 @@ int kthread_stop(struct task_struct *k)
 	/* It could exit after stop_info.k set, but before wake_up_process. */
 	get_task_struct(k);
 
+	trace_sched_kthread_stop(k);
+
 	/* Must init completion *before* thread sees kthread_stop_info.k */
 	init_completion(&kthread_stop_info.done);
 	smp_wmb();
@@ -220,6 +223,8 @@ int kthread_stop(struct task_struct *k)
 	ret = kthread_stop_info.err;
 	mutex_unlock(&kthread_stop_lock);
 
+	trace_sched_kthread_stop_ret(ret);
+
 	return ret;
 }
 EXPORT_SYMBOL(kthread_stop);

kernel/marker.c

@@ -62,7 +62,7 @@ struct marker_entry {
 	int refcount;	/* Number of times armed. 0 if disarmed. */
 	struct rcu_head rcu;
 	void *oldptr;
-	unsigned char rcu_pending:1;
+	int rcu_pending;
 	unsigned char ptype:1;
 	char name[0];	/* Contains name'\0'format'\0' */
 };
@@ -103,11 +103,11 @@ void marker_probe_cb(const struct marker *mdata, void *call_private, ...)
 	char ptype;
 
 	/*
-	 * preempt_disable does two things : disabling preemption to make sure
-	 * the teardown of the callbacks can be done correctly when they are in
-	 * modules and they insure RCU read coherency.
+	 * rcu_read_lock_sched does two things : disabling preemption to make
+	 * sure the teardown of the callbacks can be done correctly when they
+	 * are in modules and they insure RCU read coherency.
 	 */
-	preempt_disable();
+	rcu_read_lock_sched();
 	ptype = mdata->ptype;
 	if (likely(!ptype)) {
 		marker_probe_func *func;
@@ -145,7 +145,7 @@ void marker_probe_cb(const struct marker *mdata, void *call_private, ...)
 			va_end(args);
 		}
 	}
-	preempt_enable();
+	rcu_read_unlock_sched();
 }
 EXPORT_SYMBOL_GPL(marker_probe_cb);
 
@@ -162,7 +162,7 @@ void marker_probe_cb_noarg(const struct marker *mdata, void *call_private, ...)
 	va_list args;	/* not initialized */
 	char ptype;
 
-	preempt_disable();
+	rcu_read_lock_sched();
 	ptype = mdata->ptype;
 	if (likely(!ptype)) {
 		marker_probe_func *func;
@@ -195,7 +195,7 @@ void marker_probe_cb_noarg(const struct marker *mdata, void *call_private, ...)
 			multi[i].func(multi[i].probe_private, call_private,
 				mdata->format, &args);
 	}
-	preempt_enable();
+	rcu_read_unlock_sched();
 }
 EXPORT_SYMBOL_GPL(marker_probe_cb_noarg);
 
@@ -560,7 +560,7 @@ static int set_marker(struct marker_entry **entry, struct marker *elem,
  * Disable a marker and its probe callback.
  * Note: only waiting an RCU period after setting elem->call to the empty
  * function insures that the original callback is not used anymore. This insured
- * by preempt_disable around the call site.
+ * by rcu_read_lock_sched around the call site.
  */
 static void disable_marker(struct marker *elem)
 {
@@ -653,11 +653,17 @@ int marker_probe_register(const char *name, const char *format,
 	entry = get_marker(name);
 	if (!entry) {
 		entry = add_marker(name, format);
-		if (IS_ERR(entry)) {
+		if (IS_ERR(entry))
 			ret = PTR_ERR(entry);
-			goto end;
-		}
+	} else if (format) {
+		if (!entry->format)
+			ret = marker_set_format(&entry, format);
+		else if (strcmp(entry->format, format))
+			ret = -EPERM;
 	}
+	if (ret)
+		goto end;
+
 	/*
 	 * If we detect that a call_rcu is pending for this marker,
 	 * make sure it's executed now.
@@ -674,6 +680,8 @@ int marker_probe_register(const char *name, const char *format,
 	mutex_lock(&markers_mutex);
 	entry = get_marker(name);
 	WARN_ON(!entry);
+	if (entry->rcu_pending)
+		rcu_barrier_sched();
 	entry->oldptr = old;
 	entry->rcu_pending = 1;
 	/* write rcu_pending before calling the RCU callback */
@@ -717,6 +725,8 @@ int marker_probe_unregister(const char *name,
 	entry = get_marker(name);
 	if (!entry)
 		goto end;
+	if (entry->rcu_pending)
+		rcu_barrier_sched();
 	entry->oldptr = old;
 	entry->rcu_pending = 1;
 	/* write rcu_pending before calling the RCU callback */
@@ -795,6 +805,8 @@ int marker_probe_unregister_private_data(marker_probe_func *probe,
 	mutex_lock(&markers_mutex);
 	entry = get_marker_from_private_data(probe, probe_private);
 	WARN_ON(!entry);
+	if (entry->rcu_pending)
+		rcu_barrier_sched();
 	entry->oldptr = old;
 	entry->rcu_pending = 1;
 	/* write rcu_pending before calling the RCU callback */

kernel/module.c

@@ -46,6 +46,8 @@
 #include <asm/cacheflush.h>
 #include <linux/license.h>
 #include <asm/sections.h>
+#include <linux/tracepoint.h>
+#include <linux/ftrace.h>
 
 #if 0
 #define DEBUGP printk
@@ -1430,6 +1432,9 @@ static void free_module(struct module *mod)
 	/* Module unload stuff */
 	module_unload_free(mod);
 
+	/* release any pointers to mcount in this module */
+	ftrace_release(mod->module_core, mod->core_size);
+
 	/* This may be NULL, but that's OK */
 	module_free(mod, mod->module_init);
 	kfree(mod->args);
@@ -1861,9 +1866,13 @@ static noinline struct module *load_module(void __user *umod,
 	unsigned int markersindex;
 	unsigned int markersstringsindex;
 	unsigned int verboseindex;
+	unsigned int tracepointsindex;
+	unsigned int tracepointsstringsindex;
+	unsigned int mcountindex;
 	struct module *mod;
 	long err = 0;
 	void *percpu = NULL, *ptr = NULL; /* Stops spurious gcc warning */
+	void *mseg;
 	struct exception_table_entry *extable;
 	mm_segment_t old_fs;
 
@@ -2156,6 +2165,12 @@ static noinline struct module *load_module(void __user *umod,
  	markersstringsindex = find_sec(hdr, sechdrs, secstrings,
 					"__markers_strings");
 	verboseindex = find_sec(hdr, sechdrs, secstrings, "__verbose");
+	tracepointsindex = find_sec(hdr, sechdrs, secstrings, "__tracepoints");
+	tracepointsstringsindex = find_sec(hdr, sechdrs, secstrings,
+					"__tracepoints_strings");
+
+	mcountindex = find_sec(hdr, sechdrs, secstrings,
+			       "__mcount_loc");
 
 	/* Now do relocations. */
 	for (i = 1; i < hdr->e_shnum; i++) {
@@ -2183,6 +2198,12 @@ static noinline struct module *load_module(void __user *umod,
 	mod->num_markers =
 		sechdrs[markersindex].sh_size / sizeof(*mod->markers);
 #endif
+#ifdef CONFIG_TRACEPOINTS
+	mod->tracepoints = (void *)sechdrs[tracepointsindex].sh_addr;
+	mod->num_tracepoints =
+		sechdrs[tracepointsindex].sh_size / sizeof(*mod->tracepoints);
+#endif
+
 
         /* Find duplicate symbols */
 	err = verify_export_symbols(mod);
@@ -2201,12 +2222,22 @@ static noinline struct module *load_module(void __user *umod,
 
 	add_kallsyms(mod, sechdrs, symindex, strindex, secstrings);
 
+	if (!mod->taints) {
 #ifdef CONFIG_MARKERS
-	if (!mod->taints)
 		marker_update_probe_range(mod->markers,
 			mod->markers + mod->num_markers);
 #endif
 	dynamic_printk_setup(sechdrs, verboseindex);
+#ifdef CONFIG_TRACEPOINTS
+		tracepoint_update_probe_range(mod->tracepoints,
+			mod->tracepoints + mod->num_tracepoints);
+#endif
+	}
+
+	/* sechdrs[0].sh_size is always zero */
+	mseg = (void *)sechdrs[mcountindex].sh_addr;
+	ftrace_init_module(mseg, mseg + sechdrs[mcountindex].sh_size);
+
 	err = module_finalize(hdr, sechdrs, mod);
 	if (err < 0)
 		goto cleanup;
@@ -2276,6 +2307,7 @@ static noinline struct module *load_module(void __user *umod,
  cleanup:
 	kobject_del(&mod->mkobj.kobj);
 	kobject_put(&mod->mkobj.kobj);
+	ftrace_release(mod->module_core, mod->core_size);
  free_unload:
 	module_unload_free(mod);
 	module_free(mod, mod->module_init);
@@ -2759,3 +2791,50 @@ void module_update_markers(void)
 	mutex_unlock(&module_mutex);
 }
 #endif
+
+#ifdef CONFIG_TRACEPOINTS
+void module_update_tracepoints(void)
+{
+	struct module *mod;
+
+	mutex_lock(&module_mutex);
+	list_for_each_entry(mod, &modules, list)
+		if (!mod->taints)
+			tracepoint_update_probe_range(mod->tracepoints,
+				mod->tracepoints + mod->num_tracepoints);
+	mutex_unlock(&module_mutex);
+}
+
+/*
+ * Returns 0 if current not found.
+ * Returns 1 if current found.
+ */
+int module_get_iter_tracepoints(struct tracepoint_iter *iter)
+{
+	struct module *iter_mod;
+	int found = 0;
+
+	mutex_lock(&module_mutex);
+	list_for_each_entry(iter_mod, &modules, list) {
+		if (!iter_mod->taints) {
+			/*
+			 * Sorted module list
+			 */
+			if (iter_mod < iter->module)
+				continue;
+			else if (iter_mod > iter->module)
+				iter->tracepoint = NULL;
+			found = tracepoint_get_iter_range(&iter->tracepoint,
+				iter_mod->tracepoints,
+				iter_mod->tracepoints
+					+ iter_mod->num_tracepoints);
+			if (found) {
+				iter->module = iter_mod;
+				break;
+			}
+		}
+	}
+	mutex_unlock(&module_mutex);
+	return found;
+}
+#endif

kernel/notifier.c

@@ -550,7 +550,7 @@ EXPORT_SYMBOL(unregister_reboot_notifier);
 
 static ATOMIC_NOTIFIER_HEAD(die_chain);
 
-int notify_die(enum die_val val, const char *str,
+int notrace notify_die(enum die_val val, const char *str,
 	       struct pt_regs *regs, long err, int trap, int sig)
 {
 	struct die_args args = {

kernel/sched.c

@@ -71,6 +71,7 @@
 #include <linux/debugfs.h>
 #include <linux/ctype.h>
 #include <linux/ftrace.h>
+#include <trace/sched.h>
 
 #include <asm/tlb.h>
 #include <asm/irq_regs.h>
@@ -1936,6 +1937,7 @@ unsigned long wait_task_inactive(struct task_struct *p, long match_state)
 		 * just go back and repeat.
 		 */
 		rq = task_rq_lock(p, &flags);
+		trace_sched_wait_task(rq, p);
 		running = task_running(rq, p);
 		on_rq = p->se.on_rq;
 		ncsw = 0;
@@ -2297,9 +2299,7 @@ out_activate:
 	success = 1;
 
 out_running:
-	trace_mark(kernel_sched_wakeup,
-		"pid %d state %ld ## rq %p task %p rq->curr %p",
-		p->pid, p->state, rq, p, rq->curr);
+	trace_sched_wakeup(rq, p);
 	check_preempt_curr(rq, p, sync);
 
 	p->state = TASK_RUNNING;
@@ -2432,9 +2432,7 @@ void wake_up_new_task(struct task_struct *p, unsigned long clone_flags)
 		p->sched_class->task_new(rq, p);
 		inc_nr_running(rq);
 	}
-	trace_mark(kernel_sched_wakeup_new,
-		"pid %d state %ld ## rq %p task %p rq->curr %p",
-		p->pid, p->state, rq, p, rq->curr);
+	trace_sched_wakeup_new(rq, p);
 	check_preempt_curr(rq, p, 0);
 #ifdef CONFIG_SMP
 	if (p->sched_class->task_wake_up)
@@ -2607,11 +2605,7 @@ context_switch(struct rq *rq, struct task_struct *prev,
 	struct mm_struct *mm, *oldmm;
 
 	prepare_task_switch(rq, prev, next);
-	trace_mark(kernel_sched_schedule,
-		"prev_pid %d next_pid %d prev_state %ld "
-		"## rq %p prev %p next %p",
-		prev->pid, next->pid, prev->state,
-		rq, prev, next);
+	trace_sched_switch(rq, prev, next);
 	mm = next->mm;
 	oldmm = prev->active_mm;
 	/*
@@ -2851,6 +2845,7 @@ static void sched_migrate_task(struct task_struct *p, int dest_cpu)
 	    || unlikely(!cpu_active(dest_cpu)))
 		goto out;
 
+	trace_sched_migrate_task(rq, p, dest_cpu);
 	/* force the process onto the specified CPU */
 	if (migrate_task(p, dest_cpu, &req)) {
 		/* Need to wait for migration thread (might exit: take ref). */

kernel/signal.c

@@ -27,6 +27,7 @@
 #include <linux/freezer.h>
 #include <linux/pid_namespace.h>
 #include <linux/nsproxy.h>
+#include <trace/sched.h>
 
 #include <asm/param.h>
 #include <asm/uaccess.h>
@@ -803,6 +804,8 @@ static int send_signal(int sig, struct siginfo *info, struct task_struct *t,
 	struct sigpending *pending;
 	struct sigqueue *q;
 
+	trace_sched_signal_send(sig, t);
+
 	assert_spin_locked(&t->sighand->siglock);
 	if (!prepare_signal(sig, t))
 		return 0;

kernel/trace/Kconfig

@@ -1,23 +1,37 @@
 #
 # Architectures that offer an FTRACE implementation should select HAVE_FTRACE:
 #
+
+config NOP_TRACER
+	bool
+
 config HAVE_FTRACE
 	bool
+	select NOP_TRACER
 
 config HAVE_DYNAMIC_FTRACE
 	bool
 
+config HAVE_FTRACE_MCOUNT_RECORD
+	bool
+
 config TRACER_MAX_TRACE
 	bool
 
+config RING_BUFFER
+	bool
+
 config TRACING
 	bool
 	select DEBUG_FS
+	select RING_BUFFER
 	select STACKTRACE
+	select TRACEPOINTS
 
 config FTRACE
 	bool "Kernel Function Tracer"
 	depends on HAVE_FTRACE
+	depends on DEBUG_KERNEL
 	select FRAME_POINTER
 	select TRACING
 	select CONTEXT_SWITCH_TRACER
@@ -36,6 +50,7 @@ config IRQSOFF_TRACER
 	depends on TRACE_IRQFLAGS_SUPPORT
 	depends on GENERIC_TIME
 	depends on HAVE_FTRACE
+	depends on DEBUG_KERNEL
 	select TRACE_IRQFLAGS
 	select TRACING
 	select TRACER_MAX_TRACE
@@ -59,6 +74,7 @@ config PREEMPT_TRACER
 	depends on GENERIC_TIME
 	depends on PREEMPT
 	depends on HAVE_FTRACE
+	depends on DEBUG_KERNEL
 	select TRACING
 	select TRACER_MAX_TRACE
 	help
@@ -86,6 +102,7 @@ config SYSPROF_TRACER
 config SCHED_TRACER
 	bool "Scheduling Latency Tracer"
 	depends on HAVE_FTRACE
+	depends on DEBUG_KERNEL
 	select TRACING
 	select CONTEXT_SWITCH_TRACER
 	select TRACER_MAX_TRACE
@@ -96,16 +113,56 @@ config SCHED_TRACER
 config CONTEXT_SWITCH_TRACER
 	bool "Trace process context switches"
 	depends on HAVE_FTRACE
+	depends on DEBUG_KERNEL
 	select TRACING
 	select MARKERS
 	help
 	  This tracer gets called from the context switch and records
 	  all switching of tasks.
 
+config BOOT_TRACER
+	bool "Trace boot initcalls"
+	depends on HAVE_FTRACE
+	depends on DEBUG_KERNEL
+	select TRACING
+	help
+	  This tracer helps developers to optimize boot times: it records
+	  the timings of the initcalls and traces key events and the identity
+	  of tasks that can cause boot delays, such as context-switches.
+
+	  Its aim is to be parsed by the /scripts/bootgraph.pl tool to
+	  produce pretty graphics about boot inefficiencies, giving a visual
+	  representation of the delays during initcalls - but the raw
+	  /debug/tracing/trace text output is readable too.
+
+	  ( Note that tracing self tests can't be enabled if this tracer is
+	    selected, because the self-tests are an initcall as well and that
+	    would invalidate the boot trace. )
+
+config STACK_TRACER
+	bool "Trace max stack"
+	depends on HAVE_FTRACE
+	depends on DEBUG_KERNEL
+	select FTRACE
+	select STACKTRACE
+	help
+	  This special tracer records the maximum stack footprint of the
+	  kernel and displays it in debugfs/tracing/stack_trace.
+
+	  This tracer works by hooking into every function call that the
+	  kernel executes, and keeping a maximum stack depth value and
+	  stack-trace saved. Because this logic has to execute in every
+	  kernel function, all the time, this option can slow down the
+	  kernel measurably and is generally intended for kernel
+	  developers only.
+
+	  Say N if unsure.
+
 config DYNAMIC_FTRACE
 	bool "enable/disable ftrace tracepoints dynamically"
 	depends on FTRACE
 	depends on HAVE_DYNAMIC_FTRACE
+	depends on DEBUG_KERNEL
 	default y
 	help
          This option will modify all the calls to ftrace dynamically
@@ -121,12 +178,17 @@ config DYNAMIC_FTRACE
 	 were made. If so, it runs stop_machine (stops all CPUS)
 	 and modifies the code to jump over the call to ftrace.
 
+config FTRACE_MCOUNT_RECORD
+	def_bool y
+	depends on DYNAMIC_FTRACE
+	depends on HAVE_FTRACE_MCOUNT_RECORD
+
 config FTRACE_SELFTEST
 	bool
 
 config FTRACE_STARTUP_TEST
 	bool "Perform a startup test on ftrace"
-	depends on TRACING
+	depends on TRACING && DEBUG_KERNEL && !BOOT_TRACER
 	select FTRACE_SELFTEST
 	help
 	  This option performs a series of startup tests on ftrace. On bootup

kernel/trace/Makefile

@@ -11,6 +11,7 @@ obj-y += trace_selftest_dynamic.o
 endif
 
 obj-$(CONFIG_FTRACE) += libftrace.o
+obj-$(CONFIG_RING_BUFFER) += ring_buffer.o
 
 obj-$(CONFIG_TRACING) += trace.o
 obj-$(CONFIG_CONTEXT_SWITCH_TRACER) += trace_sched_switch.o
@@ -19,6 +20,9 @@ obj-$(CONFIG_FTRACE) += trace_functions.o
 obj-$(CONFIG_IRQSOFF_TRACER) += trace_irqsoff.o
 obj-$(CONFIG_PREEMPT_TRACER) += trace_irqsoff.o
 obj-$(CONFIG_SCHED_TRACER) += trace_sched_wakeup.o
+obj-$(CONFIG_NOP_TRACER) += trace_nop.o
+obj-$(CONFIG_STACK_TRACER) += trace_stack.o
 obj-$(CONFIG_MMIOTRACE) += trace_mmiotrace.o
+obj-$(CONFIG_BOOT_TRACER) += trace_boot.o
 
 libftrace-y := ftrace.o

kernel/trace/ftrace.c

@@ -81,7 +81,7 @@ void clear_ftrace_function(void)
 
 static int __register_ftrace_function(struct ftrace_ops *ops)
 {
-	/* Should never be called by interrupts */
+	/* should not be called from interrupt context */
 	spin_lock(&ftrace_lock);
 
 	ops->next = ftrace_list;
@@ -115,6 +115,7 @@ static int __unregister_ftrace_function(struct ftrace_ops *ops)
 	struct ftrace_ops **p;
 	int ret = 0;
 
+	/* should not be called from interrupt context */
 	spin_lock(&ftrace_lock);
 
 	/*
@@ -153,6 +154,30 @@ static int __unregister_ftrace_function(struct ftrace_ops *ops)
 
 #ifdef CONFIG_DYNAMIC_FTRACE
 
+#ifndef CONFIG_FTRACE_MCOUNT_RECORD
+/*
+ * The hash lock is only needed when the recording of the mcount
+ * callers are dynamic. That is, by the caller themselves and
+ * not recorded via the compilation.
+ */
+static DEFINE_SPINLOCK(ftrace_hash_lock);
+#define ftrace_hash_lock(flags)	  spin_lock_irqsave(&ftrace_hash_lock, flags)
+#define ftrace_hash_unlock(flags) \
+			spin_unlock_irqrestore(&ftrace_hash_lock, flags)
+#else
+/* This is protected via the ftrace_lock with MCOUNT_RECORD. */
+#define ftrace_hash_lock(flags)   do { (void)(flags); } while (0)
+#define ftrace_hash_unlock(flags) do { } while(0)
+#endif
+
+/*
+ * Since MCOUNT_ADDR may point to mcount itself, we do not want
+ * to get it confused by reading a reference in the code as we
+ * are parsing on objcopy output of text. Use a variable for
+ * it instead.
+ */
+static unsigned long mcount_addr = MCOUNT_ADDR;
+
 static struct task_struct *ftraced_task;
 
 enum {
@@ -171,7 +196,6 @@ static struct hlist_head ftrace_hash[FTRACE_HASHSIZE];
 
 static DEFINE_PER_CPU(int, ftrace_shutdown_disable_cpu);
 
-static DEFINE_SPINLOCK(ftrace_shutdown_lock);
 static DEFINE_MUTEX(ftraced_lock);
 static DEFINE_MUTEX(ftrace_regex_lock);
 
@@ -294,13 +318,37 @@ static inline void ftrace_del_hash(struct dyn_ftrace *node)
 
 static void ftrace_free_rec(struct dyn_ftrace *rec)
 {
-	/* no locking, only called from kstop_machine */
-
 	rec->ip = (unsigned long)ftrace_free_records;
 	ftrace_free_records = rec;
 	rec->flags |= FTRACE_FL_FREE;
 }
 
+void ftrace_release(void *start, unsigned long size)
+{
+	struct dyn_ftrace *rec;
+	struct ftrace_page *pg;
+	unsigned long s = (unsigned long)start;
+	unsigned long e = s + size;
+	int i;
+
+	if (ftrace_disabled || !start)
+		return;
+
+	/* should not be called from interrupt context */
+	spin_lock(&ftrace_lock);
+
+	for (pg = ftrace_pages_start; pg; pg = pg->next) {
+		for (i = 0; i < pg->index; i++) {
+			rec = &pg->records[i];
+
+			if ((rec->ip >= s) && (rec->ip < e))
+				ftrace_free_rec(rec);
+		}
+	}
+	spin_unlock(&ftrace_lock);
+
+}
+
 static struct dyn_ftrace *ftrace_alloc_dyn_node(unsigned long ip)
 {
 	struct dyn_ftrace *rec;
@@ -338,7 +386,6 @@ ftrace_record_ip(unsigned long ip)
 	unsigned long flags;
 	unsigned long key;
 	int resched;
-	int atomic;
 	int cpu;
 
 	if (!ftrace_enabled || ftrace_disabled)
@@ -368,9 +415,7 @@ ftrace_record_ip(unsigned long ip)
 	if (ftrace_ip_in_hash(ip, key))
 		goto out;
 
-	atomic = irqs_disabled();
-
-	spin_lock_irqsave(&ftrace_shutdown_lock, flags);
+	ftrace_hash_lock(flags);
 
 	/* This ip may have hit the hash before the lock */
 	if (ftrace_ip_in_hash(ip, key))
@@ -387,7 +432,7 @@ ftrace_record_ip(unsigned long ip)
 	ftraced_trigger = 1;
 
  out_unlock:
-	spin_unlock_irqrestore(&ftrace_shutdown_lock, flags);
+	ftrace_hash_unlock(flags);
  out:
 	per_cpu(ftrace_shutdown_disable_cpu, cpu)--;
 
@@ -531,6 +576,16 @@ static void ftrace_shutdown_replenish(void)
 	ftrace_pages->next = (void *)get_zeroed_page(GFP_KERNEL);
 }
 
+static void print_ip_ins(const char *fmt, unsigned char *p)
+{
+	int i;
+
+	printk(KERN_CONT "%s", fmt);
+
+	for (i = 0; i < MCOUNT_INSN_SIZE; i++)
+		printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
+}
+
 static int
 ftrace_code_disable(struct dyn_ftrace *rec)
 {
@@ -541,10 +596,27 @@ ftrace_code_disable(struct dyn_ftrace *rec)
 	ip = rec->ip;
 
 	nop = ftrace_nop_replace();
-	call = ftrace_call_replace(ip, MCOUNT_ADDR);
+	call = ftrace_call_replace(ip, mcount_addr);
 
 	failed = ftrace_modify_code(ip, call, nop);
 	if (failed) {
+		switch (failed) {
+		case 1:
+			WARN_ON_ONCE(1);
+			pr_info("ftrace faulted on modifying ");
+			print_ip_sym(ip);
+			break;
+		case 2:
+			WARN_ON_ONCE(1);
+			pr_info("ftrace failed to modify ");
+			print_ip_sym(ip);
+			print_ip_ins(" expected: ", call);
+			print_ip_ins(" actual: ", (unsigned char *)ip);
+			print_ip_ins(" replace: ", nop);
+			printk(KERN_CONT "\n");
+			break;
+		}
+
 		rec->flags |= FTRACE_FL_FAILED;
 		return 0;
 	}
@@ -792,47 +864,7 @@ static int ftrace_update_code(void)
 	return 1;
 }
 
-static int ftraced(void *ignore)
-{
-	unsigned long usecs;
-
-	while (!kthread_should_stop()) {
-
-		set_current_state(TASK_INTERRUPTIBLE);
-
-		/* check once a second */
-		schedule_timeout(HZ);
-
-		if (unlikely(ftrace_disabled))
-			continue;
-
-		mutex_lock(&ftrace_sysctl_lock);
-		mutex_lock(&ftraced_lock);
-		if (!ftraced_suspend && !ftraced_stop &&
-		    ftrace_update_code()) {
-			usecs = nsecs_to_usecs(ftrace_update_time);
-			if (ftrace_update_tot_cnt > 100000) {
-				ftrace_update_tot_cnt = 0;
-				pr_info("hm, dftrace overflow: %lu change%s"
-					" (%lu total) in %lu usec%s\n",
-					ftrace_update_cnt,
-					ftrace_update_cnt != 1 ? "s" : "",
-					ftrace_update_tot_cnt,
-					usecs, usecs != 1 ? "s" : "");
-				ftrace_disabled = 1;
-				WARN_ON_ONCE(1);
-			}
-		}
-		mutex_unlock(&ftraced_lock);
-		mutex_unlock(&ftrace_sysctl_lock);
-
-		ftrace_shutdown_replenish();
-	}
-	__set_current_state(TASK_RUNNING);
-	return 0;
-}
-
-static int __init ftrace_dyn_table_alloc(void)
+static int __init ftrace_dyn_table_alloc(unsigned long num_to_init)
 {
 	struct ftrace_page *pg;
 	int cnt;
@@ -859,7 +891,9 @@ static int __init ftrace_dyn_table_alloc(void)
 
 	pg = ftrace_pages = ftrace_pages_start;
 
-	cnt = NR_TO_INIT / ENTRIES_PER_PAGE;
+	cnt = num_to_init / ENTRIES_PER_PAGE;
+	pr_info("ftrace: allocating %ld hash entries in %d pages\n",
+		num_to_init, cnt);
 
 	for (i = 0; i < cnt; i++) {
 		pg->next = (void *)get_zeroed_page(GFP_KERNEL);
@@ -901,6 +935,8 @@ t_next(struct seq_file *m, void *v, loff_t *pos)
 
 	(*pos)++;
 
+	/* should not be called from interrupt context */
+	spin_lock(&ftrace_lock);
  retry:
 	if (iter->idx >= iter->pg->index) {
 		if (iter->pg->next) {
@@ -910,15 +946,13 @@ t_next(struct seq_file *m, void *v, loff_t *pos)
 		}
 	} else {
 		rec = &iter->pg->records[iter->idx++];
-		if ((!(iter->flags & FTRACE_ITER_FAILURES) &&
+		if ((rec->flags & FTRACE_FL_FREE) ||
+
+		    (!(iter->flags & FTRACE_ITER_FAILURES) &&
 		     (rec->flags & FTRACE_FL_FAILED)) ||
 
 		    ((iter->flags & FTRACE_ITER_FAILURES) &&
-		     (!(rec->flags & FTRACE_FL_FAILED) ||
-		      (rec->flags & FTRACE_FL_FREE))) ||
-
-		    ((iter->flags & FTRACE_ITER_FILTER) &&
-		     !(rec->flags & FTRACE_FL_FILTER)) ||
+		     !(rec->flags & FTRACE_FL_FAILED)) ||
 
 		    ((iter->flags & FTRACE_ITER_NOTRACE) &&
 		     !(rec->flags & FTRACE_FL_NOTRACE))) {
@@ -926,6 +960,7 @@ t_next(struct seq_file *m, void *v, loff_t *pos)
 			goto retry;
 		}
 	}
+	spin_unlock(&ftrace_lock);
 
 	iter->pos = *pos;
 
@@ -1039,8 +1074,8 @@ static void ftrace_filter_reset(int enable)
 	unsigned long type = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
 	unsigned i;
 
-	/* keep kstop machine from running */
-	preempt_disable();
+	/* should not be called from interrupt context */
+	spin_lock(&ftrace_lock);
 	if (enable)
 		ftrace_filtered = 0;
 	pg = ftrace_pages_start;
@@ -1053,7 +1088,7 @@ static void ftrace_filter_reset(int enable)
 		}
 		pg = pg->next;
 	}
-	preempt_enable();
+	spin_unlock(&ftrace_lock);
 }
 
 static int
@@ -1165,8 +1200,8 @@ ftrace_match(unsigned char *buff, int len, int enable)
 		}
 	}
 
-	/* keep kstop machine from running */
-	preempt_disable();
+	/* should not be called from interrupt context */
+	spin_lock(&ftrace_lock);
 	if (enable)
 		ftrace_filtered = 1;
 	pg = ftrace_pages_start;
@@ -1203,7 +1238,7 @@ ftrace_match(unsigned char *buff, int len, int enable)
 		}
 		pg = pg->next;
 	}
-	preempt_enable();
+	spin_unlock(&ftrace_lock);
 }
 
 static ssize_t
@@ -1556,6 +1591,114 @@ static __init int ftrace_init_debugfs(void)
 
 fs_initcall(ftrace_init_debugfs);
 
+#ifdef CONFIG_FTRACE_MCOUNT_RECORD
+static int ftrace_convert_nops(unsigned long *start,
+			       unsigned long *end)
+{
+	unsigned long *p;
+	unsigned long addr;
+	unsigned long flags;
+
+	p = start;
+	while (p < end) {
+		addr = ftrace_call_adjust(*p++);
+		/* should not be called from interrupt context */
+		spin_lock(&ftrace_lock);
+		ftrace_record_ip(addr);
+		spin_unlock(&ftrace_lock);
+		ftrace_shutdown_replenish();
+	}
+
+	/* p is ignored */
+	local_irq_save(flags);
+	__ftrace_update_code(p);
+	local_irq_restore(flags);
+
+	return 0;
+}
+
+void ftrace_init_module(unsigned long *start, unsigned long *end)
+{
+	if (ftrace_disabled || start == end)
+		return;
+	ftrace_convert_nops(start, end);
+}
+
+extern unsigned long __start_mcount_loc[];
+extern unsigned long __stop_mcount_loc[];
+
+void __init ftrace_init(void)
+{
+	unsigned long count, addr, flags;
+	int ret;
+
+	/* Keep the ftrace pointer to the stub */
+	addr = (unsigned long)ftrace_stub;
+
+	local_irq_save(flags);
+	ftrace_dyn_arch_init(&addr);
+	local_irq_restore(flags);
+
+	/* ftrace_dyn_arch_init places the return code in addr */
+	if (addr)
+		goto failed;
+
+	count = __stop_mcount_loc - __start_mcount_loc;
+
+	ret = ftrace_dyn_table_alloc(count);
+	if (ret)
+		goto failed;
+
+	last_ftrace_enabled = ftrace_enabled = 1;
+
+	ret = ftrace_convert_nops(__start_mcount_loc,
+				  __stop_mcount_loc);
+
+	return;
+ failed:
+	ftrace_disabled = 1;
+}
+#else /* CONFIG_FTRACE_MCOUNT_RECORD */
+static int ftraced(void *ignore)
+{
+	unsigned long usecs;
+
+	while (!kthread_should_stop()) {
+
+		set_current_state(TASK_INTERRUPTIBLE);
+
+		/* check once a second */
+		schedule_timeout(HZ);
+
+		if (unlikely(ftrace_disabled))
+			continue;
+
+		mutex_lock(&ftrace_sysctl_lock);
+		mutex_lock(&ftraced_lock);
+		if (!ftraced_suspend && !ftraced_stop &&
+		    ftrace_update_code()) {
+			usecs = nsecs_to_usecs(ftrace_update_time);
+			if (ftrace_update_tot_cnt > 100000) {
+				ftrace_update_tot_cnt = 0;
+				pr_info("hm, dftrace overflow: %lu change%s"
+					" (%lu total) in %lu usec%s\n",
+					ftrace_update_cnt,
+					ftrace_update_cnt != 1 ? "s" : "",
+					ftrace_update_tot_cnt,
+					usecs, usecs != 1 ? "s" : "");
+				ftrace_disabled = 1;
+				WARN_ON_ONCE(1);
+			}
+		}
+		mutex_unlock(&ftraced_lock);
+		mutex_unlock(&ftrace_sysctl_lock);
+
+		ftrace_shutdown_replenish();
+	}
+	__set_current_state(TASK_RUNNING);
+	return 0;
+}
+
 static int __init ftrace_dynamic_init(void)
 {
 	struct task_struct *p;
@@ -1572,7 +1715,7 @@ static int __init ftrace_dynamic_init(void)
 		goto failed;
 	}
 
-	ret = ftrace_dyn_table_alloc();
+	ret = ftrace_dyn_table_alloc(NR_TO_INIT);
 	if (ret)
 		goto failed;
 
@@ -1593,6 +1736,8 @@ static int __init ftrace_dynamic_init(void)
 }
 
 core_initcall(ftrace_dynamic_init);
+#endif /* CONFIG_FTRACE_MCOUNT_RECORD */
+
 #else
 # define ftrace_startup()		do { } while (0)
 # define ftrace_shutdown()		do { } while (0)

kernel/trace/ring_buffer.c

@@ -0,0 +1,2014 @@
+/*
+ * Generic ring buffer
+ *
+ * Copyright (C) 2008 Steven Rostedt <srostedt@redhat.com>
+ */
+#include <linux/ring_buffer.h>
+#include <linux/spinlock.h>
+#include <linux/debugfs.h>
+#include <linux/uaccess.h>
+#include <linux/module.h>
+#include <linux/percpu.h>
+#include <linux/mutex.h>
+#include <linux/sched.h>	/* used for sched_clock() (for now) */
+#include <linux/init.h>
+#include <linux/hash.h>
+#include <linux/list.h>
+#include <linux/fs.h>
+
+/* Up this if you want to test the TIME_EXTENTS and normalization */
+#define DEBUG_SHIFT 0
+
+/* FIXME!!! */
+u64 ring_buffer_time_stamp(int cpu)
+{
+	/* shift to debug/test normalization and TIME_EXTENTS */
+	return sched_clock() << DEBUG_SHIFT;
+}
+
+void ring_buffer_normalize_time_stamp(int cpu, u64 *ts)
+{
+	/* Just stupid testing the normalize function and deltas */
+	*ts >>= DEBUG_SHIFT;
+}
+
+#define RB_EVNT_HDR_SIZE (sizeof(struct ring_buffer_event))
+#define RB_ALIGNMENT_SHIFT	2
+#define RB_ALIGNMENT		(1 << RB_ALIGNMENT_SHIFT)
+#define RB_MAX_SMALL_DATA	28
+
+enum {
+	RB_LEN_TIME_EXTEND = 8,
+	RB_LEN_TIME_STAMP = 16,
+};
+
+/* inline for ring buffer fast paths */
+static inline unsigned
+rb_event_length(struct ring_buffer_event *event)
+{
+	unsigned length;
+
+	switch (event->type) {
+	case RINGBUF_TYPE_PADDING:
+		/* undefined */
+		return -1;
+
+	case RINGBUF_TYPE_TIME_EXTEND:
+		return RB_LEN_TIME_EXTEND;
+
+	case RINGBUF_TYPE_TIME_STAMP:
+		return RB_LEN_TIME_STAMP;
+
+	case RINGBUF_TYPE_DATA:
+		if (event->len)
+			length = event->len << RB_ALIGNMENT_SHIFT;
+		else
+			length = event->array[0];
+		return length + RB_EVNT_HDR_SIZE;
+	default:
+		BUG();
+	}
+	/* not hit */
+	return 0;
+}
+
+/**
+ * ring_buffer_event_length - return the length of the event
+ * @event: the event to get the length of
+ */
+unsigned ring_buffer_event_length(struct ring_buffer_event *event)
+{
+	return rb_event_length(event);
+}
+
+/* inline for ring buffer fast paths */
+static inline void *
+rb_event_data(struct ring_buffer_event *event)
+{
+	BUG_ON(event->type != RINGBUF_TYPE_DATA);
+	/* If length is in len field, then array[0] has the data */
+	if (event->len)
+		return (void *)&event->array[0];
+	/* Otherwise length is in array[0] and array[1] has the data */
+	return (void *)&event->array[1];
+}
+
+/**
+ * ring_buffer_event_data - return the data of the event
+ * @event: the event to get the data from
+ */
+void *ring_buffer_event_data(struct ring_buffer_event *event)
+{
+	return rb_event_data(event);
+}
+
+#define for_each_buffer_cpu(buffer, cpu)		\
+	for_each_cpu_mask(cpu, buffer->cpumask)
+
+#define TS_SHIFT	27
+#define TS_MASK		((1ULL << TS_SHIFT) - 1)
+#define TS_DELTA_TEST	(~TS_MASK)
+
+/*
+ * This hack stolen from mm/slob.c.
+ * We can store per page timing information in the page frame of the page.
+ * Thanks to Peter Zijlstra for suggesting this idea.
+ */
+struct buffer_page {
+	u64		 time_stamp;	/* page time stamp */
+	local_t		 write;		/* index for next write */
+	local_t		 commit;	/* write commited index */
+	unsigned	 read;		/* index for next read */
+	struct list_head list;		/* list of free pages */
+	void *page;			/* Actual data page */
+};
+
+/*
+ * Also stolen from mm/slob.c. Thanks to Mathieu Desnoyers for pointing
+ * this issue out.
+ */
+static inline void free_buffer_page(struct buffer_page *bpage)
+{
+	if (bpage->page)
+		__free_page(bpage->page);
+	kfree(bpage);
+}
+
+/*
+ * We need to fit the time_stamp delta into 27 bits.
+ */
+static inline int test_time_stamp(u64 delta)
+{
+	if (delta & TS_DELTA_TEST)
+		return 1;
+	return 0;
+}
+
+#define BUF_PAGE_SIZE PAGE_SIZE
+
+/*
+ * head_page == tail_page && head == tail then buffer is empty.
+ */
+struct ring_buffer_per_cpu {
+	int				cpu;
+	struct ring_buffer		*buffer;
+	spinlock_t			lock;
+	struct lock_class_key		lock_key;
+	struct list_head		pages;
+	struct buffer_page		*head_page;	/* read from head */
+	struct buffer_page		*tail_page;	/* write to tail */
+	struct buffer_page		*commit_page;	/* commited pages */
+	struct buffer_page		*reader_page;
+	unsigned long			overrun;
+	unsigned long			entries;
+	u64				write_stamp;
+	u64				read_stamp;
+	atomic_t			record_disabled;
+};
+
+struct ring_buffer {
+	unsigned long			size;
+	unsigned			pages;
+	unsigned			flags;
+	int				cpus;
+	cpumask_t			cpumask;
+	atomic_t			record_disabled;
+
+	struct mutex			mutex;
+
+	struct ring_buffer_per_cpu	**buffers;
+};
+
+struct ring_buffer_iter {
+	struct ring_buffer_per_cpu	*cpu_buffer;
+	unsigned long			head;
+	struct buffer_page		*head_page;
+	u64				read_stamp;
+};
+
+#define RB_WARN_ON(buffer, cond)				\
+	do {							\
+		if (unlikely(cond)) {				\
+			atomic_inc(&buffer->record_disabled);	\
+			WARN_ON(1);				\
+		}						\
+	} while (0)
+
+#define RB_WARN_ON_RET(buffer, cond)				\
+	do {							\
+		if (unlikely(cond)) {				\
+			atomic_inc(&buffer->record_disabled);	\
+			WARN_ON(1);				\
+			return -1;				\
+		}						\
+	} while (0)
+
+#define RB_WARN_ON_ONCE(buffer, cond)				\
+	do {							\
+		static int once;				\
+		if (unlikely(cond) && !once) {			\
+			once++;					\
+			atomic_inc(&buffer->record_disabled);	\
+			WARN_ON(1);				\
+		}						\
+	} while (0)
+
+/**
+ * check_pages - integrity check of buffer pages
+ * @cpu_buffer: CPU buffer with pages to test
+ *
+ * As a safty measure we check to make sure the data pages have not
+ * been corrupted.
+ */
+static int rb_check_pages(struct ring_buffer_per_cpu *cpu_buffer)
+{
+	struct list_head *head = &cpu_buffer->pages;
+	struct buffer_page *page, *tmp;
+
+	RB_WARN_ON_RET(cpu_buffer, head->next->prev != head);
+	RB_WARN_ON_RET(cpu_buffer, head->prev->next != head);
+
+	list_for_each_entry_safe(page, tmp, head, list) {
+		RB_WARN_ON_RET(cpu_buffer,
+			       page->list.next->prev != &page->list);
+		RB_WARN_ON_RET(cpu_buffer,
+			       page->list.prev->next != &page->list);
+	}
+
+	return 0;
+}
+
+static int rb_allocate_pages(struct ring_buffer_per_cpu *cpu_buffer,
+			     unsigned nr_pages)
+{
+	struct list_head *head = &cpu_buffer->pages;
+	struct buffer_page *page, *tmp;
+	unsigned long addr;
+	LIST_HEAD(pages);
+	unsigned i;
+
+	for (i = 0; i < nr_pages; i++) {
+		page = kzalloc_node(ALIGN(sizeof(*page), cache_line_size()),
+				    GFP_KERNEL, cpu_to_node(cpu_buffer->cpu));
+		if (!page)
+			goto free_pages;
+		list_add(&page->list, &pages);
+
+		addr = __get_free_page(GFP_KERNEL);
+		if (!addr)
+			goto free_pages;
+		page->page = (void *)addr;
+	}
+
+	list_splice(&pages, head);
+
+	rb_check_pages(cpu_buffer);
+
+	return 0;
+
+ free_pages:
+	list_for_each_entry_safe(page, tmp, &pages, list) {
+		list_del_init(&page->list);
+		free_buffer_page(page);
+	}
+	return -ENOMEM;
+}
+
+static struct ring_buffer_per_cpu *
+rb_allocate_cpu_buffer(struct ring_buffer *buffer, int cpu)
+{
+	struct ring_buffer_per_cpu *cpu_buffer;
+	struct buffer_page *page;
+	unsigned long addr;
+	int ret;
+
+	cpu_buffer = kzalloc_node(ALIGN(sizeof(*cpu_buffer), cache_line_size()),
+				  GFP_KERNEL, cpu_to_node(cpu));
+	if (!cpu_buffer)
+		return NULL;
+
+	cpu_buffer->cpu = cpu;
+	cpu_buffer->buffer = buffer;
+	spin_lock_init(&cpu_buffer->lock);
+	INIT_LIST_HEAD(&cpu_buffer->pages);
+
+	page = kzalloc_node(ALIGN(sizeof(*page), cache_line_size()),
+			    GFP_KERNEL, cpu_to_node(cpu));
+	if (!page)
+		goto fail_free_buffer;
+
+	cpu_buffer->reader_page = page;
+	addr = __get_free_page(GFP_KERNEL);
+	if (!addr)
+		goto fail_free_reader;
+	page->page = (void *)addr;
+
+	INIT_LIST_HEAD(&cpu_buffer->reader_page->list);
+
+	ret = rb_allocate_pages(cpu_buffer, buffer->pages);
+	if (ret < 0)
+		goto fail_free_reader;
+
+	cpu_buffer->head_page
+		= list_entry(cpu_buffer->pages.next, struct buffer_page, list);
+	cpu_buffer->tail_page = cpu_buffer->commit_page = cpu_buffer->head_page;
+
+	return cpu_buffer;
+
+ fail_free_reader:
+	free_buffer_page(cpu_buffer->reader_page);
+
+ fail_free_buffer:
+	kfree(cpu_buffer);
+	return NULL;
+}
+
+static void rb_free_cpu_buffer(struct ring_buffer_per_cpu *cpu_buffer)
+{
+	struct list_head *head = &cpu_buffer->pages;
+	struct buffer_page *page, *tmp;
+
+	list_del_init(&cpu_buffer->reader_page->list);
+	free_buffer_page(cpu_buffer->reader_page);
+
+	list_for_each_entry_safe(page, tmp, head, list) {
+		list_del_init(&page->list);
+		free_buffer_page(page);
+	}
+	kfree(cpu_buffer);
+}
+
+/*
+ * Causes compile errors if the struct buffer_page gets bigger
+ * than the struct page.
+ */
+extern int ring_buffer_page_too_big(void);
+
+/**
+ * ring_buffer_alloc - allocate a new ring_buffer
+ * @size: the size in bytes that is needed.
+ * @flags: attributes to set for the ring buffer.
+ *
+ * Currently the only flag that is available is the RB_FL_OVERWRITE
+ * flag. This flag means that the buffer will overwrite old data
+ * when the buffer wraps. If this flag is not set, the buffer will
+ * drop data when the tail hits the head.
+ */
+struct ring_buffer *ring_buffer_alloc(unsigned long size, unsigned flags)
+{
+	struct ring_buffer *buffer;
+	int bsize;
+	int cpu;
+
+	/* Paranoid! Optimizes out when all is well */
+	if (sizeof(struct buffer_page) > sizeof(struct page))
+		ring_buffer_page_too_big();
+
+
+	/* keep it in its own cache line */
+	buffer = kzalloc(ALIGN(sizeof(*buffer), cache_line_size()),
+			 GFP_KERNEL);
+	if (!buffer)
+		return NULL;
+
+	buffer->pages = DIV_ROUND_UP(size, BUF_PAGE_SIZE);
+	buffer->flags = flags;
+
+	/* need at least two pages */
+	if (buffer->pages == 1)
+		buffer->pages++;
+
+	buffer->cpumask = cpu_possible_map;
+	buffer->cpus = nr_cpu_ids;
+
+	bsize = sizeof(void *) * nr_cpu_ids;
+	buffer->buffers = kzalloc(ALIGN(bsize, cache_line_size()),
+				  GFP_KERNEL);
+	if (!buffer->buffers)
+		goto fail_free_buffer;
+
+	for_each_buffer_cpu(buffer, cpu) {
+		buffer->buffers[cpu] =
+			rb_allocate_cpu_buffer(buffer, cpu);
+		if (!buffer->buffers[cpu])
+			goto fail_free_buffers;
+	}
+
+	mutex_init(&buffer->mutex);
+
+	return buffer;
+
+ fail_free_buffers:
+	for_each_buffer_cpu(buffer, cpu) {
+		if (buffer->buffers[cpu])
+			rb_free_cpu_buffer(buffer->buffers[cpu]);
+	}
+	kfree(buffer->buffers);
+
+ fail_free_buffer:
+	kfree(buffer);
+	return NULL;
+}
+
+/**
+ * ring_buffer_free - free a ring buffer.
+ * @buffer: the buffer to free.
+ */
+void
+ring_buffer_free(struct ring_buffer *buffer)
+{
+	int cpu;
+
+	for_each_buffer_cpu(buffer, cpu)
+		rb_free_cpu_buffer(buffer->buffers[cpu]);
+
+	kfree(buffer);
+}
+
+static void rb_reset_cpu(struct ring_buffer_per_cpu *cpu_buffer);
+
+static void
+rb_remove_pages(struct ring_buffer_per_cpu *cpu_buffer, unsigned nr_pages)
+{
+	struct buffer_page *page;
+	struct list_head *p;
+	unsigned i;
+
+	atomic_inc(&cpu_buffer->record_disabled);
+	synchronize_sched();
+
+	for (i = 0; i < nr_pages; i++) {
+		BUG_ON(list_empty(&cpu_buffer->pages));
+		p = cpu_buffer->pages.next;
+		page = list_entry(p, struct buffer_page, list);
+		list_del_init(&page->list);
+		free_buffer_page(page);
+	}
+	BUG_ON(list_empty(&cpu_buffer->pages));
+
+	rb_reset_cpu(cpu_buffer);
+
+	rb_check_pages(cpu_buffer);
+
+	atomic_dec(&cpu_buffer->record_disabled);
+
+}
+
+static void
+rb_insert_pages(struct ring_buffer_per_cpu *cpu_buffer,
+		struct list_head *pages, unsigned nr_pages)
+{
+	struct buffer_page *page;
+	struct list_head *p;
+	unsigned i;
+
+	atomic_inc(&cpu_buffer->record_disabled);
+	synchronize_sched();
+
+	for (i = 0; i < nr_pages; i++) {
+		BUG_ON(list_empty(pages));
+		p = pages->next;
+		page = list_entry(p, struct buffer_page, list);
+		list_del_init(&page->list);
+		list_add_tail(&page->list, &cpu_buffer->pages);
+	}
+	rb_reset_cpu(cpu_buffer);
+
+	rb_check_pages(cpu_buffer);
+
+	atomic_dec(&cpu_buffer->record_disabled);
+}
+
+/**
+ * ring_buffer_resize - resize the ring buffer
+ * @buffer: the buffer to resize.
+ * @size: the new size.
+ *
+ * The tracer is responsible for making sure that the buffer is
+ * not being used while changing the size.
+ * Note: We may be able to change the above requirement by using
+ *  RCU synchronizations.
+ *
+ * Minimum size is 2 * BUF_PAGE_SIZE.
+ *
+ * Returns -1 on failure.
+ */
+int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size)
+{
+	struct ring_buffer_per_cpu *cpu_buffer;
+	unsigned nr_pages, rm_pages, new_pages;
+	struct buffer_page *page, *tmp;
+	unsigned long buffer_size;
+	unsigned long addr;
+	LIST_HEAD(pages);
+	int i, cpu;
+
+	size = DIV_ROUND_UP(size, BUF_PAGE_SIZE);
+	size *= BUF_PAGE_SIZE;
+	buffer_size = buffer->pages * BUF_PAGE_SIZE;
+
+	/* we need a minimum of two pages */
+	if (size < BUF_PAGE_SIZE * 2)
+		size = BUF_PAGE_SIZE * 2;
+
+	if (size == buffer_size)
+		return size;
+
+	mutex_lock(&buffer->mutex);
+
+	nr_pages = DIV_ROUND_UP(size, BUF_PAGE_SIZE);
+
+	if (size < buffer_size) {
+
+		/* easy case, just free pages */
+		BUG_ON(nr_pages >= buffer->pages);
+
+		rm_pages = buffer->pages - nr_pages;
+
+		for_each_buffer_cpu(buffer, cpu) {
+			cpu_buffer = buffer->buffers[cpu];
+			rb_remove_pages(cpu_buffer, rm_pages);
+		}
+		goto out;
+	}
+
+	/*
+	 * This is a bit more difficult. We only want to add pages
+	 * when we can allocate enough for all CPUs. We do this
+	 * by allocating all the pages and storing them on a local
+	 * link list. If we succeed in our allocation, then we
+	 * add these pages to the cpu_buffers. Otherwise we just free
+	 * them all and return -ENOMEM;
+	 */
+	BUG_ON(nr_pages <= buffer->pages);
+	new_pages = nr_pages - buffer->pages;
+
+	for_each_buffer_cpu(buffer, cpu) {
+		for (i = 0; i < new_pages; i++) {
+			page = kzalloc_node(ALIGN(sizeof(*page),
+						  cache_line_size()),
+					    GFP_KERNEL, cpu_to_node(cpu));
+			if (!page)
+				goto free_pages;
+			list_add(&page->list, &pages);
+			addr = __get_free_page(GFP_KERNEL);
+			if (!addr)
+				goto free_pages;
+			page->page = (void *)addr;
+		}
+	}
+
+	for_each_buffer_cpu(buffer, cpu) {
+		cpu_buffer = buffer->buffers[cpu];
+		rb_insert_pages(cpu_buffer, &pages, new_pages);
+	}
+
+	BUG_ON(!list_empty(&pages));
+
+ out:
+	buffer->pages = nr_pages;
+	mutex_unlock(&buffer->mutex);
+
+	return size;
+
+ free_pages:
+	list_for_each_entry_safe(page, tmp, &pages, list) {
+		list_del_init(&page->list);
+		free_buffer_page(page);
+	}
+	return -ENOMEM;
+}
+
+static inline int rb_null_event(struct ring_buffer_event *event)
+{
+	return event->type == RINGBUF_TYPE_PADDING;
+}
+
+static inline void *__rb_page_index(struct buffer_page *page, unsigned index)
+{
+	return page->page + index;
+}
+
+static inline struct ring_buffer_event *
+rb_reader_event(struct ring_buffer_per_cpu *cpu_buffer)
+{
+	return __rb_page_index(cpu_buffer->reader_page,
+			       cpu_buffer->reader_page->read);
+}
+
+static inline struct ring_buffer_event *
+rb_head_event(struct ring_buffer_per_cpu *cpu_buffer)
+{
+	return __rb_page_index(cpu_buffer->head_page,
+			       cpu_buffer->head_page->read);
+}
+
+static inline struct ring_buffer_event *
+rb_iter_head_event(struct ring_buffer_iter *iter)
+{
+	return __rb_page_index(iter->head_page, iter->head);
+}
+
+static inline unsigned rb_page_write(struct buffer_page *bpage)
+{
+	return local_read(&bpage->write);
+}
+
+static inline unsigned rb_page_commit(struct buffer_page *bpage)
+{
+	return local_read(&bpage->commit);
+}
+
+/* Size is determined by what has been commited */
+static inline unsigned rb_page_size(struct buffer_page *bpage)
+{
+	return rb_page_commit(bpage);
+}
+
+static inline unsigned
+rb_commit_index(struct ring_buffer_per_cpu *cpu_buffer)
+{
+	return rb_page_commit(cpu_buffer->commit_page);
+}
+
+static inline unsigned rb_head_size(struct ring_buffer_per_cpu *cpu_buffer)
+{
+	return rb_page_commit(cpu_buffer->head_page);
+}
+
+/*
+ * When the tail hits the head and the buffer is in overwrite mode,
+ * the head jumps to the next page and all content on the previous
+ * page is discarded. But before doing so, we update the overrun
+ * variable of the buffer.
+ */
+static void rb_update_overflow(struct ring_buffer_per_cpu *cpu_buffer)
+{
+	struct ring_buffer_event *event;
+	unsigned long head;
+
+	for (head = 0; head < rb_head_size(cpu_buffer);
+	     head += rb_event_length(event)) {
+
+		event = __rb_page_index(cpu_buffer->head_page, head);
+		BUG_ON(rb_null_event(event));
+		/* Only count data entries */
+		if (event->type != RINGBUF_TYPE_DATA)
+			continue;
+		cpu_buffer->overrun++;
+		cpu_buffer->entries--;
+	}
+}
+
+static inline void rb_inc_page(struct ring_buffer_per_cpu *cpu_buffer,
+			       struct buffer_page **page)
+{
+	struct list_head *p = (*page)->list.next;
+
+	if (p == &cpu_buffer->pages)
+		p = p->next;
+
+	*page = list_entry(p, struct buffer_page, list);
+}
+
+static inline unsigned
+rb_event_index(struct ring_buffer_event *event)
+{
+	unsigned long addr = (unsigned long)event;
+
+	return (addr & ~PAGE_MASK) - (PAGE_SIZE - BUF_PAGE_SIZE);
+}
+
+static inline int
+rb_is_commit(struct ring_buffer_per_cpu *cpu_buffer,
+	     struct ring_buffer_event *event)
+{
+	unsigned long addr = (unsigned long)event;
+	unsigned long index;
+
+	index = rb_event_index(event);
+	addr &= PAGE_MASK;
+
+	return cpu_buffer->commit_page->page == (void *)addr &&
+		rb_commit_index(cpu_buffer) == index;
+}
+
+static inline void
+rb_set_commit_event(struct ring_buffer_per_cpu *cpu_buffer,
+		    struct ring_buffer_event *event)
+{
+	unsigned long addr = (unsigned long)event;
+	unsigned long index;
+
+	index = rb_event_index(event);
+	addr &= PAGE_MASK;
+
+	while (cpu_buffer->commit_page->page != (void *)addr) {
+		RB_WARN_ON(cpu_buffer,
+			   cpu_buffer->commit_page == cpu_buffer->tail_page);
+		cpu_buffer->commit_page->commit =
+			cpu_buffer->commit_page->write;
+		rb_inc_page(cpu_buffer, &cpu_buffer->commit_page);
+		cpu_buffer->write_stamp = cpu_buffer->commit_page->time_stamp;
+	}
+
+	/* Now set the commit to the event's index */
+	local_set(&cpu_buffer->commit_page->commit, index);
+}
+
+static inline void
+rb_set_commit_to_write(struct ring_buffer_per_cpu *cpu_buffer)
+{
+	/*
+	 * We only race with interrupts and NMIs on this CPU.
+	 * If we own the commit event, then we can commit
+	 * all others that interrupted us, since the interruptions
+	 * are in stack format (they finish before they come
+	 * back to us). This allows us to do a simple loop to
+	 * assign the commit to the tail.
+	 */
+	while (cpu_buffer->commit_page != cpu_buffer->tail_page) {
+		cpu_buffer->commit_page->commit =
+			cpu_buffer->commit_page->write;
+		rb_inc_page(cpu_buffer, &cpu_buffer->commit_page);
+		cpu_buffer->write_stamp = cpu_buffer->commit_page->time_stamp;
+		/* add barrier to keep gcc from optimizing too much */
+		barrier();
+	}
+	while (rb_commit_index(cpu_buffer) !=
+	       rb_page_write(cpu_buffer->commit_page)) {
+		cpu_buffer->commit_page->commit =
+			cpu_buffer->commit_page->write;
+		barrier();
+	}
+}
+
+static void rb_reset_reader_page(struct ring_buffer_per_cpu *cpu_buffer)
+{
+	cpu_buffer->read_stamp = cpu_buffer->reader_page->time_stamp;
+	cpu_buffer->reader_page->read = 0;
+}
+
+static inline void rb_inc_iter(struct ring_buffer_iter *iter)
+{
+	struct ring_buffer_per_cpu *cpu_buffer = iter->cpu_buffer;
+
+	/*
+	 * The iterator could be on the reader page (it starts there).
+	 * But the head could have moved, since the reader was
+	 * found. Check for this case and assign the iterator
+	 * to the head page instead of next.
+	 */
+	if (iter->head_page == cpu_buffer->reader_page)
+		iter->head_page = cpu_buffer->head_page;
+	else
+		rb_inc_page(cpu_buffer, &iter->head_page);
+
+	iter->read_stamp = iter->head_page->time_stamp;
+	iter->head = 0;
+}
+
+/**
+ * ring_buffer_update_event - update event type and data
+ * @event: the even to update
+ * @type: the type of event
+ * @length: the size of the event field in the ring buffer
+ *
+ * Update the type and data fields of the event. The length
+ * is the actual size that is written to the ring buffer,
+ * and with this, we can determine what to place into the
+ * data field.
+ */
+static inline void
+rb_update_event(struct ring_buffer_event *event,
+			 unsigned type, unsigned length)
+{
+	event->type = type;
+
+	switch (type) {
+
+	case RINGBUF_TYPE_PADDING:
+		break;
+
+	case RINGBUF_TYPE_TIME_EXTEND:
+		event->len =
+			(RB_LEN_TIME_EXTEND + (RB_ALIGNMENT-1))
+			>> RB_ALIGNMENT_SHIFT;
+		break;
+
+	case RINGBUF_TYPE_TIME_STAMP:
+		event->len =
+			(RB_LEN_TIME_STAMP + (RB_ALIGNMENT-1))
+			>> RB_ALIGNMENT_SHIFT;
+		break;
+
+	case RINGBUF_TYPE_DATA:
+		length -= RB_EVNT_HDR_SIZE;
+		if (length > RB_MAX_SMALL_DATA) {
+			event->len = 0;
+			event->array[0] = length;
+		} else
+			event->len =
+				(length + (RB_ALIGNMENT-1))
+				>> RB_ALIGNMENT_SHIFT;
+		break;
+	default:
+		BUG();
+	}
+}
+
+static inline unsigned rb_calculate_event_length(unsigned length)
+{
+	struct ring_buffer_event event; /* Used only for sizeof array */
+
+	/* zero length can cause confusions */
+	if (!length)
+		length = 1;
+
+	if (length > RB_MAX_SMALL_DATA)
+		length += sizeof(event.array[0]);
+
+	length += RB_EVNT_HDR_SIZE;
+	length = ALIGN(length, RB_ALIGNMENT);
+
+	return length;
+}
+
+static struct ring_buffer_event *
+__rb_reserve_next(struct ring_buffer_per_cpu *cpu_buffer,
+		  unsigned type, unsigned long length, u64 *ts)
+{
+	struct buffer_page *tail_page, *head_page, *reader_page;
+	unsigned long tail, write;
+	struct ring_buffer *buffer = cpu_buffer->buffer;
+	struct ring_buffer_event *event;
+	unsigned long flags;
+
+	tail_page = cpu_buffer->tail_page;
+	write = local_add_return(length, &tail_page->write);
+	tail = write - length;
+
+	/* See if we shot pass the end of this buffer page */
+	if (write > BUF_PAGE_SIZE) {
+		struct buffer_page *next_page = tail_page;
+
+		spin_lock_irqsave(&cpu_buffer->lock, flags);
+
+		rb_inc_page(cpu_buffer, &next_page);
+
+		head_page = cpu_buffer->head_page;
+		reader_page = cpu_buffer->reader_page;
+
+		/* we grabbed the lock before incrementing */
+		RB_WARN_ON(cpu_buffer, next_page == reader_page);
+
+		/*
+		 * If for some reason, we had an interrupt storm that made
+		 * it all the way around the buffer, bail, and warn
+		 * about it.
+		 */
+		if (unlikely(next_page == cpu_buffer->commit_page)) {
+			WARN_ON_ONCE(1);
+			goto out_unlock;
+		}
+
+		if (next_page == head_page) {
+			if (!(buffer->flags & RB_FL_OVERWRITE)) {
+				/* reset write */
+				if (tail <= BUF_PAGE_SIZE)
+					local_set(&tail_page->write, tail);
+				goto out_unlock;
+			}
+
+			/* tail_page has not moved yet? */
+			if (tail_page == cpu_buffer->tail_page) {
+				/* count overflows */
+				rb_update_overflow(cpu_buffer);
+
+				rb_inc_page(cpu_buffer, &head_page);
+				cpu_buffer->head_page = head_page;
+				cpu_buffer->head_page->read = 0;
+			}
+		}
+
+		/*
+		 * If the tail page is still the same as what we think
+		 * it is, then it is up to us to update the tail
+		 * pointer.
+		 */
+		if (tail_page == cpu_buffer->tail_page) {
+			local_set(&next_page->write, 0);
+			local_set(&next_page->commit, 0);
+			cpu_buffer->tail_page = next_page;
+
+			/* reread the time stamp */
+			*ts = ring_buffer_time_stamp(cpu_buffer->cpu);
+			cpu_buffer->tail_page->time_stamp = *ts;
+		}
+
+		/*
+		 * The actual tail page has moved forward.
+		 */
+		if (tail < BUF_PAGE_SIZE) {
+			/* Mark the rest of the page with padding */
+			event = __rb_page_index(tail_page, tail);
+			event->type = RINGBUF_TYPE_PADDING;
+		}
+
+		if (tail <= BUF_PAGE_SIZE)
+			/* Set the write back to the previous setting */
+			local_set(&tail_page->write, tail);
+
+		/*
+		 * If this was a commit entry that failed,
+		 * increment that too
+		 */
+		if (tail_page == cpu_buffer->commit_page &&
+		    tail == rb_commit_index(cpu_buffer)) {
+			rb_set_commit_to_write(cpu_buffer);
+		}
+
+		spin_unlock_irqrestore(&cpu_buffer->lock, flags);
+
+		/* fail and let the caller try again */
+		return ERR_PTR(-EAGAIN);
+	}
+
+	/* We reserved something on the buffer */
+
+	BUG_ON(write > BUF_PAGE_SIZE);
+
+	event = __rb_page_index(tail_page, tail);
+	rb_update_event(event, type, length);
+
+	/*
+	 * If this is a commit and the tail is zero, then update
+	 * this page's time stamp.
+	 */
+	if (!tail && rb_is_commit(cpu_buffer, event))
+		cpu_buffer->commit_page->time_stamp = *ts;
+
+	return event;
+
+ out_unlock:
+	spin_unlock_irqrestore(&cpu_buffer->lock, flags);
+	return NULL;
+}
+
+static int
+rb_add_time_stamp(struct ring_buffer_per_cpu *cpu_buffer,
+		  u64 *ts, u64 *delta)
+{
+	struct ring_buffer_event *event;
+	static int once;
+	int ret;
+
+	if (unlikely(*delta > (1ULL << 59) && !once++)) {
+		printk(KERN_WARNING "Delta way too big! %llu"
+		       " ts=%llu write stamp = %llu\n",
+		       *delta, *ts, cpu_buffer->write_stamp);
+		WARN_ON(1);
+	}
+
+	/*
+	 * The delta is too big, we to add a
+	 * new timestamp.
+	 */
+	event = __rb_reserve_next(cpu_buffer,
+				  RINGBUF_TYPE_TIME_EXTEND,
+				  RB_LEN_TIME_EXTEND,
+				  ts);
+	if (!event)
+		return -EBUSY;
+
+	if (PTR_ERR(event) == -EAGAIN)
+		return -EAGAIN;
+
+	/* Only a commited time event can update the write stamp */
+	if (rb_is_commit(cpu_buffer, event)) {
+		/*
+		 * If this is the first on the page, then we need to
+		 * update the page itself, and just put in a zero.
+		 */
+		if (rb_event_index(event)) {
+			event->time_delta = *delta & TS_MASK;
+			event->array[0] = *delta >> TS_SHIFT;
+		} else {
+			cpu_buffer->commit_page->time_stamp = *ts;
+			event->time_delta = 0;
+			event->array[0] = 0;
+		}
+		cpu_buffer->write_stamp = *ts;
+		/* let the caller know this was the commit */
+		ret = 1;
+	} else {
+		/* Darn, this is just wasted space */
+		event->time_delta = 0;
+		event->array[0] = 0;
+		ret = 0;
+	}
+
+	*delta = 0;
+
+	return ret;
+}
+
+static struct ring_buffer_event *
+rb_reserve_next_event(struct ring_buffer_per_cpu *cpu_buffer,
+		      unsigned type, unsigned long length)
+{
+	struct ring_buffer_event *event;
+	u64 ts, delta;
+	int commit = 0;
+
+ again:
+	ts = ring_buffer_time_stamp(cpu_buffer->cpu);
+
+	/*
+	 * Only the first commit can update the timestamp.
+	 * Yes there is a race here. If an interrupt comes in
+	 * just after the conditional and it traces too, then it
+	 * will also check the deltas. More than one timestamp may
+	 * also be made. But only the entry that did the actual
+	 * commit will be something other than zero.
+	 */
+	if (cpu_buffer->tail_page == cpu_buffer->commit_page &&
+	    rb_page_write(cpu_buffer->tail_page) ==
+	    rb_commit_index(cpu_buffer)) {
+
+		delta = ts - cpu_buffer->write_stamp;
+
+		/* make sure this delta is calculated here */
+		barrier();
+
+		/* Did the write stamp get updated already? */
+		if (unlikely(ts < cpu_buffer->write_stamp))
+			goto again;
+
+		if (test_time_stamp(delta)) {
+
+			commit = rb_add_time_stamp(cpu_buffer, &ts, &delta);
+
+			if (commit == -EBUSY)
+				return NULL;
+
+			if (commit == -EAGAIN)
+				goto again;
+
+			RB_WARN_ON(cpu_buffer, commit < 0);
+		}
+	} else
+		/* Non commits have zero deltas */
+		delta = 0;
+
+	event = __rb_reserve_next(cpu_buffer, type, length, &ts);
+	if (PTR_ERR(event) == -EAGAIN)
+		goto again;
+
+	if (!event) {
+		if (unlikely(commit))
+			/*
+			 * Ouch! We needed a timestamp and it was commited. But
+			 * we didn't get our event reserved.
+			 */
+			rb_set_commit_to_write(cpu_buffer);
+		return NULL;
+	}
+
+	/*
+	 * If the timestamp was commited, make the commit our entry
+	 * now so that we will update it when needed.
+	 */
+	if (commit)
+		rb_set_commit_event(cpu_buffer, event);
+	else if (!rb_is_commit(cpu_buffer, event))
+		delta = 0;
+
+	event->time_delta = delta;
+
+	return event;
+}
+
+static DEFINE_PER_CPU(int, rb_need_resched);
+
+/**
+ * ring_buffer_lock_reserve - reserve a part of the buffer
+ * @buffer: the ring buffer to reserve from
+ * @length: the length of the data to reserve (excluding event header)
+ * @flags: a pointer to save the interrupt flags
+ *
+ * Returns a reseverd event on the ring buffer to copy directly to.
+ * The user of this interface will need to get the body to write into
+ * and can use the ring_buffer_event_data() interface.
+ *
+ * The length is the length of the data needed, not the event length
+ * which also includes the event header.
+ *
+ * Must be paired with ring_buffer_unlock_commit, unless NULL is returned.
+ * If NULL is returned, then nothing has been allocated or locked.
+ */
+struct ring_buffer_event *
+ring_buffer_lock_reserve(struct ring_buffer *buffer,
+			 unsigned long length,
+			 unsigned long *flags)
+{
+	struct ring_buffer_per_cpu *cpu_buffer;
+	struct ring_buffer_event *event;
+	int cpu, resched;
+
+	if (atomic_read(&buffer->record_disabled))
+		return NULL;
+
+	/* If we are tracing schedule, we don't want to recurse */
+	resched = need_resched();
+	preempt_disable_notrace();
+
+	cpu = raw_smp_processor_id();
+
+	if (!cpu_isset(cpu, buffer->cpumask))
+		goto out;
+
+	cpu_buffer = buffer->buffers[cpu];
+
+	if (atomic_read(&cpu_buffer->record_disabled))
+		goto out;
+
+	length = rb_calculate_event_length(length);
+	if (length > BUF_PAGE_SIZE)
+		goto out;
+
+	event = rb_reserve_next_event(cpu_buffer, RINGBUF_TYPE_DATA, length);
+	if (!event)
+		goto out;
+
+	/*
+	 * Need to store resched state on this cpu.
+	 * Only the first needs to.
+	 */
+
+	if (preempt_count() == 1)
+		per_cpu(rb_need_resched, cpu) = resched;
+
+	return event;
+
+ out:
+	if (resched)
+		preempt_enable_notrace();
+	else
+		preempt_enable_notrace();
+	return NULL;
+}
+
+static void rb_commit(struct ring_buffer_per_cpu *cpu_buffer,
+		      struct ring_buffer_event *event)
+{
+	cpu_buffer->entries++;
+
+	/* Only process further if we own the commit */
+	if (!rb_is_commit(cpu_buffer, event))
+		return;
+
+	cpu_buffer->write_stamp += event->time_delta;
+
+	rb_set_commit_to_write(cpu_buffer);
+}
+
+/**
+ * ring_buffer_unlock_commit - commit a reserved
+ * @buffer: The buffer to commit to
+ * @event: The event pointer to commit.
+ * @flags: the interrupt flags received from ring_buffer_lock_reserve.
+ *
+ * This commits the data to the ring buffer, and releases any locks held.
+ *
+ * Must be paired with ring_buffer_lock_reserve.
+ */
+int ring_buffer_unlock_commit(struct ring_buffer *buffer,
+			      struct ring_buffer_event *event,
+			      unsigned long flags)
+{
+	struct ring_buffer_per_cpu *cpu_buffer;
+	int cpu = raw_smp_processor_id();
+
+	cpu_buffer = buffer->buffers[cpu];
+
+	rb_commit(cpu_buffer, event);
+
+	/*
+	 * Only the last preempt count needs to restore preemption.
+	 */
+	if (preempt_count() == 1) {
+		if (per_cpu(rb_need_resched, cpu))
+			preempt_enable_no_resched_notrace();
+		else
+			preempt_enable_notrace();
+	} else
+		preempt_enable_no_resched_notrace();
+
+	return 0;
+}
+
+/**
+ * ring_buffer_write - write data to the buffer without reserving
+ * @buffer: The ring buffer to write to.
+ * @length: The length of the data being written (excluding the event header)
+ * @data: The data to write to the buffer.
+ *
+ * This is like ring_buffer_lock_reserve and ring_buffer_unlock_commit as
+ * one function. If you already have the data to write to the buffer, it
+ * may be easier to simply call this function.
+ *
+ * Note, like ring_buffer_lock_reserve, the length is the length of the data
+ * and not the length of the event which would hold the header.
+ */
+int ring_buffer_write(struct ring_buffer *buffer,
+			unsigned long length,
+			void *data)
+{
+	struct ring_buffer_per_cpu *cpu_buffer;
+	struct ring_buffer_event *event;
+	unsigned long event_length;
+	void *body;
+	int ret = -EBUSY;
+	int cpu, resched;
+
+	if (atomic_read(&buffer->record_disabled))
+		return -EBUSY;
+
+	resched = need_resched();
+	preempt_disable_notrace();
+
+	cpu = raw_smp_processor_id();
+
+	if (!cpu_isset(cpu, buffer->cpumask))
+		goto out;
+
+	cpu_buffer = buffer->buffers[cpu];
+
+	if (atomic_read(&cpu_buffer->record_disabled))
+		goto out;
+
+	event_length = rb_calculate_event_length(length);
+	event = rb_reserve_next_event(cpu_buffer,
+				      RINGBUF_TYPE_DATA, event_length);
+	if (!event)
+		goto out;
+
+	body = rb_event_data(event);
+
+	memcpy(body, data, length);
+
+	rb_commit(cpu_buffer, event);
+
+	ret = 0;
+ out:
+	if (resched)
+		preempt_enable_no_resched_notrace();
+	else
+		preempt_enable_notrace();
+
+	return ret;
+}
+
+static inline int rb_per_cpu_empty(struct ring_buffer_per_cpu *cpu_buffer)
+{
+	struct buffer_page *reader = cpu_buffer->reader_page;
+	struct buffer_page *head = cpu_buffer->head_page;
+	struct buffer_page *commit = cpu_buffer->commit_page;
+
+	return reader->read == rb_page_commit(reader) &&
+		(commit == reader ||
+		 (commit == head &&
+		  head->read == rb_page_commit(commit)));
+}
+
+/**
+ * ring_buffer_record_disable - stop all writes into the buffer
+ * @buffer: The ring buffer to stop writes to.
+ *
+ * This prevents all writes to the buffer. Any attempt to write
+ * to the buffer after this will fail and return NULL.
+ *
+ * The caller should call synchronize_sched() after this.
+ */
+void ring_buffer_record_disable(struct ring_buffer *buffer)
+{
+	atomic_inc(&buffer->record_disabled);
+}
+
+/**
+ * ring_buffer_record_enable - enable writes to the buffer
+ * @buffer: The ring buffer to enable writes
+ *
+ * Note, multiple disables will need the same number of enables
+ * to truely enable the writing (much like preempt_disable).
+ */
+void ring_buffer_record_enable(struct ring_buffer *buffer)
+{
+	atomic_dec(&buffer->record_disabled);
+}
+
+/**
+ * ring_buffer_record_disable_cpu - stop all writes into the cpu_buffer
+ * @buffer: The ring buffer to stop writes to.
+ * @cpu: The CPU buffer to stop
+ *
+ * This prevents all writes to the buffer. Any attempt to write
+ * to the buffer after this will fail and return NULL.
+ *
+ * The caller should call synchronize_sched() after this.
+ */
+void ring_buffer_record_disable_cpu(struct ring_buffer *buffer, int cpu)
+{
+	struct ring_buffer_per_cpu *cpu_buffer;
+
+	if (!cpu_isset(cpu, buffer->cpumask))
+		return;
+
+	cpu_buffer = buffer->buffers[cpu];
+	atomic_inc(&cpu_buffer->record_disabled);
+}
+
+/**
+ * ring_buffer_record_enable_cpu - enable writes to the buffer
+ * @buffer: The ring buffer to enable writes
+ * @cpu: The CPU to enable.
+ *
+ * Note, multiple disables will need the same number of enables
+ * to truely enable the writing (much like preempt_disable).
+ */
+void ring_buffer_record_enable_cpu(struct ring_buffer *buffer, int cpu)
+{
+	struct ring_buffer_per_cpu *cpu_buffer;
+
+	if (!cpu_isset(cpu, buffer->cpumask))
+		return;
+
+	cpu_buffer = buffer->buffers[cpu];
+	atomic_dec(&cpu_buffer->record_disabled);
+}
+
+/**
+ * ring_buffer_entries_cpu - get the number of entries in a cpu buffer
+ * @buffer: The ring buffer
+ * @cpu: The per CPU buffer to get the entries from.
+ */
+unsigned long ring_buffer_entries_cpu(struct ring_buffer *buffer, int cpu)
+{
+	struct ring_buffer_per_cpu *cpu_buffer;
+
+	if (!cpu_isset(cpu, buffer->cpumask))
+		return 0;
+
+	cpu_buffer = buffer->buffers[cpu];
+	return cpu_buffer->entries;
+}
+
+/**
+ * ring_buffer_overrun_cpu - get the number of overruns in a cpu_buffer
+ * @buffer: The ring buffer
+ * @cpu: The per CPU buffer to get the number of overruns from
+ */
+unsigned long ring_buffer_overrun_cpu(struct ring_buffer *buffer, int cpu)
+{
+	struct ring_buffer_per_cpu *cpu_buffer;
+
+	if (!cpu_isset(cpu, buffer->cpumask))
+		return 0;
+
+	cpu_buffer = buffer->buffers[cpu];
+	return cpu_buffer->overrun;
+}
+
+/**
+ * ring_buffer_entries - get the number of entries in a buffer
+ * @buffer: The ring buffer
+ *
+ * Returns the total number of entries in the ring buffer
+ * (all CPU entries)
+ */
+unsigned long ring_buffer_entries(struct ring_buffer *buffer)
+{
+	struct ring_buffer_per_cpu *cpu_buffer;
+	unsigned long entries = 0;
+	int cpu;
+
+	/* if you care about this being correct, lock the buffer */
+	for_each_buffer_cpu(buffer, cpu) {
+		cpu_buffer = buffer->buffers[cpu];
+		entries += cpu_buffer->entries;
+	}
+
+	return entries;
+}
+
+/**
+ * ring_buffer_overrun_cpu - get the number of overruns in buffer
+ * @buffer: The ring buffer
+ *
+ * Returns the total number of overruns in the ring buffer
+ * (all CPU entries)
+ */
+unsigned long ring_buffer_overruns(struct ring_buffer *buffer)
+{
+	struct ring_buffer_per_cpu *cpu_buffer;
+	unsigned long overruns = 0;
+	int cpu;
+
+	/* if you care about this being correct, lock the buffer */
+	for_each_buffer_cpu(buffer, cpu) {
+		cpu_buffer = buffer->buffers[cpu];
+		overruns += cpu_buffer->overrun;
+	}
+
+	return overruns;
+}
+
+/**
+ * ring_buffer_iter_reset - reset an iterator
+ * @iter: The iterator to reset
+ *
+ * Resets the iterator, so that it will start from the beginning
+ * again.
+ */
+void ring_buffer_iter_reset(struct ring_buffer_iter *iter)
+{
+	struct ring_buffer_per_cpu *cpu_buffer = iter->cpu_buffer;
+
+	/* Iterator usage is expected to have record disabled */
+	if (list_empty(&cpu_buffer->reader_page->list)) {
+		iter->head_page = cpu_buffer->head_page;
+		iter->head = cpu_buffer->head_page->read;
+	} else {
+		iter->head_page = cpu_buffer->reader_page;
+		iter->head = cpu_buffer->reader_page->read;
+	}
+	if (iter->head)
+		iter->read_stamp = cpu_buffer->read_stamp;
+	else
+		iter->read_stamp = iter->head_page->time_stamp;
+}
+
+/**
+ * ring_buffer_iter_empty - check if an iterator has no more to read
+ * @iter: The iterator to check
+ */
+int ring_buffer_iter_empty(struct ring_buffer_iter *iter)
+{
+	struct ring_buffer_per_cpu *cpu_buffer;
+
+	cpu_buffer = iter->cpu_buffer;
+
+	return iter->head_page == cpu_buffer->commit_page &&
+		iter->head == rb_commit_index(cpu_buffer);
+}
+
+static void
+rb_update_read_stamp(struct ring_buffer_per_cpu *cpu_buffer,
+		     struct ring_buffer_event *event)
+{
+	u64 delta;
+
+	switch (event->type) {
+	case RINGBUF_TYPE_PADDING:
+		return;
+
+	case RINGBUF_TYPE_TIME_EXTEND:
+		delta = event->array[0];
+		delta <<= TS_SHIFT;
+		delta += event->time_delta;
+		cpu_buffer->read_stamp += delta;
+		return;
+
+	case RINGBUF_TYPE_TIME_STAMP:
+		/* FIXME: not implemented */
+		return;
+
+	case RINGBUF_TYPE_DATA:
+		cpu_buffer->read_stamp += event->time_delta;
+		return;
+
+	default:
+		BUG();
+	}
+	return;
+}
+
+static void
+rb_update_iter_read_stamp(struct ring_buffer_iter *iter,
+			  struct ring_buffer_event *event)
+{
+	u64 delta;
+
+	switch (event->type) {
+	case RINGBUF_TYPE_PADDING:
+		return;
+
+	case RINGBUF_TYPE_TIME_EXTEND:
+		delta = event->array[0];
+		delta <<= TS_SHIFT;
+		delta += event->time_delta;
+		iter->read_stamp += delta;
+		return;
+
+	case RINGBUF_TYPE_TIME_STAMP:
+		/* FIXME: not implemented */
+		return;
+
+	case RINGBUF_TYPE_DATA:
+		iter->read_stamp += event->time_delta;
+		return;
+
+	default:
+		BUG();
+	}
+	return;
+}
+
+static struct buffer_page *
+rb_get_reader_page(struct ring_buffer_per_cpu *cpu_buffer)
+{
+	struct buffer_page *reader = NULL;
+	unsigned long flags;
+
+	spin_lock_irqsave(&cpu_buffer->lock, flags);
+
+ again:
+	reader = cpu_buffer->reader_page;
+
+	/* If there's more to read, return this page */
+	if (cpu_buffer->reader_page->read < rb_page_size(reader))
+		goto out;
+
+	/* Never should we have an index greater than the size */
+	RB_WARN_ON(cpu_buffer,
+		   cpu_buffer->reader_page->read > rb_page_size(reader));
+
+	/* check if we caught up to the tail */
+	reader = NULL;
+	if (cpu_buffer->commit_page == cpu_buffer->reader_page)
+		goto out;
+
+	/*
+	 * Splice the empty reader page into the list around the head.
+	 * Reset the reader page to size zero.
+	 */
+
+	reader = cpu_buffer->head_page;
+	cpu_buffer->reader_page->list.next = reader->list.next;
+	cpu_buffer->reader_page->list.prev = reader->list.prev;
+
+	local_set(&cpu_buffer->reader_page->write, 0);
+	local_set(&cpu_buffer->reader_page->commit, 0);
+
+	/* Make the reader page now replace the head */
+	reader->list.prev->next = &cpu_buffer->reader_page->list;
+	reader->list.next->prev = &cpu_buffer->reader_page->list;
+
+	/*
+	 * If the tail is on the reader, then we must set the head
+	 * to the inserted page, otherwise we set it one before.
+	 */
+	cpu_buffer->head_page = cpu_buffer->reader_page;
+
+	if (cpu_buffer->commit_page != reader)
+		rb_inc_page(cpu_buffer, &cpu_buffer->head_page);
+
+	/* Finally update the reader page to the new head */
+	cpu_buffer->reader_page = reader;
+	rb_reset_reader_page(cpu_buffer);
+
+	goto again;
+
+ out:
+	spin_unlock_irqrestore(&cpu_buffer->lock, flags);
+
+	return reader;
+}
+
+static void rb_advance_reader(struct ring_buffer_per_cpu *cpu_buffer)
+{
+	struct ring_buffer_event *event;
+	struct buffer_page *reader;
+	unsigned length;
+
+	reader = rb_get_reader_page(cpu_buffer);
+
+	/* This function should not be called when buffer is empty */
+	BUG_ON(!reader);
+
+	event = rb_reader_event(cpu_buffer);
+
+	if (event->type == RINGBUF_TYPE_DATA)
+		cpu_buffer->entries--;
+
+	rb_update_read_stamp(cpu_buffer, event);
+
+	length = rb_event_length(event);
+	cpu_buffer->reader_page->read += length;
+}
+
+static void rb_advance_iter(struct ring_buffer_iter *iter)
+{
+	struct ring_buffer *buffer;
+	struct ring_buffer_per_cpu *cpu_buffer;
+	struct ring_buffer_event *event;
+	unsigned length;
+
+	cpu_buffer = iter->cpu_buffer;
+	buffer = cpu_buffer->buffer;
+
+	/*
+	 * Check if we are at the end of the buffer.
+	 */
+	if (iter->head >= rb_page_size(iter->head_page)) {
+		BUG_ON(iter->head_page == cpu_buffer->commit_page);
+		rb_inc_iter(iter);
+		return;
+	}
+
+	event = rb_iter_head_event(iter);
+
+	length = rb_event_length(event);
+
+	/*
+	 * This should not be called to advance the header if we are
+	 * at the tail of the buffer.
+	 */
+	BUG_ON((iter->head_page == cpu_buffer->commit_page) &&
+	       (iter->head + length > rb_commit_index(cpu_buffer)));
+
+	rb_update_iter_read_stamp(iter, event);
+
+	iter->head += length;
+
+	/* check for end of page padding */
+	if ((iter->head >= rb_page_size(iter->head_page)) &&
+	    (iter->head_page != cpu_buffer->commit_page))
+		rb_advance_iter(iter);
+}
+
+/**
+ * ring_buffer_peek - peek at the next event to be read
+ * @buffer: The ring buffer to read
+ * @cpu: The cpu to peak at
+ * @ts: The timestamp counter of this event.
+ *
+ * This will return the event that will be read next, but does
+ * not consume the data.
+ */
+struct ring_buffer_event *
+ring_buffer_peek(struct ring_buffer *buffer, int cpu, u64 *ts)
+{
+	struct ring_buffer_per_cpu *cpu_buffer;
+	struct ring_buffer_event *event;
+	struct buffer_page *reader;
+
+	if (!cpu_isset(cpu, buffer->cpumask))
+		return NULL;
+
+	cpu_buffer = buffer->buffers[cpu];
+
+ again:
+	reader = rb_get_reader_page(cpu_buffer);
+	if (!reader)
+		return NULL;
+
+	event = rb_reader_event(cpu_buffer);
+
+	switch (event->type) {
+	case RINGBUF_TYPE_PADDING:
+		RB_WARN_ON(cpu_buffer, 1);
+		rb_advance_reader(cpu_buffer);
+		return NULL;
+
+	case RINGBUF_TYPE_TIME_EXTEND:
+		/* Internal data, OK to advance */
+		rb_advance_reader(cpu_buffer);
+		goto again;
+
+	case RINGBUF_TYPE_TIME_STAMP:
+		/* FIXME: not implemented */
+		rb_advance_reader(cpu_buffer);
+		goto again;
+
+	case RINGBUF_TYPE_DATA:
+		if (ts) {
+			*ts = cpu_buffer->read_stamp + event->time_delta;
+			ring_buffer_normalize_time_stamp(cpu_buffer->cpu, ts);
+		}
+		return event;
+
+	default:
+		BUG();
+	}
+
+	return NULL;
+}
+
+/**
+ * ring_buffer_iter_peek - peek at the next event to be read
+ * @iter: The ring buffer iterator
+ * @ts: The timestamp counter of this event.
+ *
+ * This will return the event that will be read next, but does
+ * not increment the iterator.
+ */
+struct ring_buffer_event *
+ring_buffer_iter_peek(struct ring_buffer_iter *iter, u64 *ts)
+{
+	struct ring_buffer *buffer;
+	struct ring_buffer_per_cpu *cpu_buffer;
+	struct ring_buffer_event *event;
+
+	if (ring_buffer_iter_empty(iter))
+		return NULL;
+
+	cpu_buffer = iter->cpu_buffer;
+	buffer = cpu_buffer->buffer;
+
+ again:
+	if (rb_per_cpu_empty(cpu_buffer))
+		return NULL;
+
+	event = rb_iter_head_event(iter);
+
+	switch (event->type) {
+	case RINGBUF_TYPE_PADDING:
+		rb_inc_iter(iter);
+		goto again;
+
+	case RINGBUF_TYPE_TIME_EXTEND:
+		/* Internal data, OK to advance */
+		rb_advance_iter(iter);
+		goto again;
+
+	case RINGBUF_TYPE_TIME_STAMP:
+		/* FIXME: not implemented */
+		rb_advance_iter(iter);
+		goto again;
+
+	case RINGBUF_TYPE_DATA:
+		if (ts) {
+			*ts = iter->read_stamp + event->time_delta;
+			ring_buffer_normalize_time_stamp(cpu_buffer->cpu, ts);
+		}
+		return event;
+
+	default:
+		BUG();
+	}
+
+	return NULL;
+}
+
+/**
+ * ring_buffer_consume - return an event and consume it
+ * @buffer: The ring buffer to get the next event from
+ *
+ * Returns the next event in the ring buffer, and that event is consumed.
+ * Meaning, that sequential reads will keep returning a different event,
+ * and eventually empty the ring buffer if the producer is slower.
+ */
+struct ring_buffer_event *
+ring_buffer_consume(struct ring_buffer *buffer, int cpu, u64 *ts)
+{
+	struct ring_buffer_per_cpu *cpu_buffer;
+	struct ring_buffer_event *event;
+
+	if (!cpu_isset(cpu, buffer->cpumask))
+		return NULL;
+
+	event = ring_buffer_peek(buffer, cpu, ts);
+	if (!event)
+		return NULL;
+
+	cpu_buffer = buffer->buffers[cpu];
+	rb_advance_reader(cpu_buffer);
+
+	return event;
+}
+
+/**
+ * ring_buffer_read_start - start a non consuming read of the buffer
+ * @buffer: The ring buffer to read from
+ * @cpu: The cpu buffer to iterate over
+ *
+ * This starts up an iteration through the buffer. It also disables
+ * the recording to the buffer until the reading is finished.
+ * This prevents the reading from being corrupted. This is not
+ * a consuming read, so a producer is not expected.
+ *
+ * Must be paired with ring_buffer_finish.
+ */
+struct ring_buffer_iter *
+ring_buffer_read_start(struct ring_buffer *buffer, int cpu)
+{
+	struct ring_buffer_per_cpu *cpu_buffer;
+	struct ring_buffer_iter *iter;
+	unsigned long flags;
+
+	if (!cpu_isset(cpu, buffer->cpumask))
+		return NULL;
+
+	iter = kmalloc(sizeof(*iter), GFP_KERNEL);
+	if (!iter)
+		return NULL;
+
+	cpu_buffer = buffer->buffers[cpu];
+
+	iter->cpu_buffer = cpu_buffer;
+
+	atomic_inc(&cpu_buffer->record_disabled);
+	synchronize_sched();
+
+	spin_lock_irqsave(&cpu_buffer->lock, flags);
+	ring_buffer_iter_reset(iter);
+	spin_unlock_irqrestore(&cpu_buffer->lock, flags);
+
+	return iter;
+}
+
+/**
+ * ring_buffer_finish - finish reading the iterator of the buffer
+ * @iter: The iterator retrieved by ring_buffer_start
+ *
+ * This re-enables the recording to the buffer, and frees the
+ * iterator.
+ */
+void
+ring_buffer_read_finish(struct ring_buffer_iter *iter)
+{
+	struct ring_buffer_per_cpu *cpu_buffer = iter->cpu_buffer;
+
+	atomic_dec(&cpu_buffer->record_disabled);
+	kfree(iter);
+}
+
+/**
+ * ring_buffer_read - read the next item in the ring buffer by the iterator
+ * @iter: The ring buffer iterator
+ * @ts: The time stamp of the event read.
+ *
+ * This reads the next event in the ring buffer and increments the iterator.
+ */
+struct ring_buffer_event *
+ring_buffer_read(struct ring_buffer_iter *iter, u64 *ts)
+{
+	struct ring_buffer_event *event;
+
+	event = ring_buffer_iter_peek(iter, ts);
+	if (!event)
+		return NULL;
+
+	rb_advance_iter(iter);
+
+	return event;
+}
+
+/**
+ * ring_buffer_size - return the size of the ring buffer (in bytes)
+ * @buffer: The ring buffer.
+ */
+unsigned long ring_buffer_size(struct ring_buffer *buffer)
+{
+	return BUF_PAGE_SIZE * buffer->pages;
+}
+
+static void
+rb_reset_cpu(struct ring_buffer_per_cpu *cpu_buffer)
+{
+	cpu_buffer->head_page
+		= list_entry(cpu_buffer->pages.next, struct buffer_page, list);
+	local_set(&cpu_buffer->head_page->write, 0);
+	local_set(&cpu_buffer->head_page->commit, 0);
+
+	cpu_buffer->head_page->read = 0;
+
+	cpu_buffer->tail_page = cpu_buffer->head_page;
+	cpu_buffer->commit_page = cpu_buffer->head_page;
+
+	INIT_LIST_HEAD(&cpu_buffer->reader_page->list);
+	local_set(&cpu_buffer->reader_page->write, 0);
+	local_set(&cpu_buffer->reader_page->commit, 0);
+	cpu_buffer->reader_page->read = 0;
+
+	cpu_buffer->overrun = 0;
+	cpu_buffer->entries = 0;
+}
+
+/**
+ * ring_buffer_reset_cpu - reset a ring buffer per CPU buffer
+ * @buffer: The ring buffer to reset a per cpu buffer of
+ * @cpu: The CPU buffer to be reset
+ */
+void ring_buffer_reset_cpu(struct ring_buffer *buffer, int cpu)
+{
+	struct ring_buffer_per_cpu *cpu_buffer = buffer->buffers[cpu];
+	unsigned long flags;
+
+	if (!cpu_isset(cpu, buffer->cpumask))
+		return;
+
+	spin_lock_irqsave(&cpu_buffer->lock, flags);
+
+	rb_reset_cpu(cpu_buffer);
+
+	spin_unlock_irqrestore(&cpu_buffer->lock, flags);
+}
+
+/**
+ * ring_buffer_reset - reset a ring buffer
+ * @buffer: The ring buffer to reset all cpu buffers
+ */
+void ring_buffer_reset(struct ring_buffer *buffer)
+{
+	int cpu;
+
+	for_each_buffer_cpu(buffer, cpu)
+		ring_buffer_reset_cpu(buffer, cpu);
+}
+
+/**
+ * rind_buffer_empty - is the ring buffer empty?
+ * @buffer: The ring buffer to test
+ */
+int ring_buffer_empty(struct ring_buffer *buffer)
+{
+	struct ring_buffer_per_cpu *cpu_buffer;
+	int cpu;
+
+	/* yes this is racy, but if you don't like the race, lock the buffer */
+	for_each_buffer_cpu(buffer, cpu) {
+		cpu_buffer = buffer->buffers[cpu];
+		if (!rb_per_cpu_empty(cpu_buffer))
+			return 0;
+	}
+	return 1;
+}
+
+/**
+ * ring_buffer_empty_cpu - is a cpu buffer of a ring buffer empty?
+ * @buffer: The ring buffer
+ * @cpu: The CPU buffer to test
+ */
+int ring_buffer_empty_cpu(struct ring_buffer *buffer, int cpu)
+{
+	struct ring_buffer_per_cpu *cpu_buffer;
+
+	if (!cpu_isset(cpu, buffer->cpumask))
+		return 1;
+
+	cpu_buffer = buffer->buffers[cpu];
+	return rb_per_cpu_empty(cpu_buffer);
+}
+
+/**
+ * ring_buffer_swap_cpu - swap a CPU buffer between two ring buffers
+ * @buffer_a: One buffer to swap with
+ * @buffer_b: The other buffer to swap with
+ *
+ * This function is useful for tracers that want to take a "snapshot"
+ * of a CPU buffer and has another back up buffer lying around.
+ * it is expected that the tracer handles the cpu buffer not being
+ * used at the moment.
+ */
+int ring_buffer_swap_cpu(struct ring_buffer *buffer_a,
+			 struct ring_buffer *buffer_b, int cpu)
+{
+	struct ring_buffer_per_cpu *cpu_buffer_a;
+	struct ring_buffer_per_cpu *cpu_buffer_b;
+
+	if (!cpu_isset(cpu, buffer_a->cpumask) ||
+	    !cpu_isset(cpu, buffer_b->cpumask))
+		return -EINVAL;
+
+	/* At least make sure the two buffers are somewhat the same */
+	if (buffer_a->size != buffer_b->size ||
+	    buffer_a->pages != buffer_b->pages)
+		return -EINVAL;
+
+	cpu_buffer_a = buffer_a->buffers[cpu];
+	cpu_buffer_b = buffer_b->buffers[cpu];
+
+	/*
+	 * We can't do a synchronize_sched here because this
+	 * function can be called in atomic context.
+	 * Normally this will be called from the same CPU as cpu.
+	 * If not it's up to the caller to protect this.
+	 */
+	atomic_inc(&cpu_buffer_a->record_disabled);
+	atomic_inc(&cpu_buffer_b->record_disabled);
+
+	buffer_a->buffers[cpu] = cpu_buffer_b;
+	buffer_b->buffers[cpu] = cpu_buffer_a;
+
+	cpu_buffer_b->buffer = buffer_a;
+	cpu_buffer_a->buffer = buffer_b;
+
+	atomic_dec(&cpu_buffer_a->record_disabled);
+	atomic_dec(&cpu_buffer_b->record_disabled);
+
+	return 0;
+}
+

kernel/trace/trace.h

@@ -5,7 +5,9 @@
 #include <asm/atomic.h>
 #include <linux/sched.h>
 #include <linux/clocksource.h>
+#include <linux/ring_buffer.h>
 #include <linux/mmiotrace.h>
+#include <linux/ftrace.h>
 
 enum trace_type {
 	__TRACE_FIRST_TYPE = 0,
@@ -13,38 +15,60 @@ enum trace_type {
 	TRACE_FN,
 	TRACE_CTX,
 	TRACE_WAKE,
+	TRACE_CONT,
 	TRACE_STACK,
+	TRACE_PRINT,
 	TRACE_SPECIAL,
 	TRACE_MMIO_RW,
 	TRACE_MMIO_MAP,
+	TRACE_BOOT,
 
 	__TRACE_LAST_TYPE
 };
 
+/*
+ * The trace entry - the most basic unit of tracing. This is what
+ * is printed in the end as a single line in the trace output, such as:
+ *
+ *     bash-15816 [01]   235.197585: idle_cpu <- irq_enter
+ */
+struct trace_entry {
+	unsigned char		type;
+	unsigned char		cpu;
+	unsigned char		flags;
+	unsigned char		preempt_count;
+	int			pid;
+};
+
 /*
  * Function trace entry - function address and parent function addres:
  */
 struct ftrace_entry {
+	struct trace_entry	ent;
 	unsigned long		ip;
 	unsigned long		parent_ip;
 };
+extern struct tracer boot_tracer;
 
 /*
  * Context switch trace entry - which task (and prio) we switched from/to:
  */
 struct ctx_switch_entry {
+	struct trace_entry	ent;
 	unsigned int		prev_pid;
 	unsigned char		prev_prio;
 	unsigned char		prev_state;
 	unsigned int		next_pid;
 	unsigned char		next_prio;
 	unsigned char		next_state;
+	unsigned int		next_cpu;
 };
 
 /*
  * Special (free-form) trace entry:
  */
 struct special_entry {
+	struct trace_entry	ent;
 	unsigned long		arg1;
 	unsigned long		arg2;
 	unsigned long		arg3;
@@ -57,33 +81,60 @@ struct special_entry {
 #define FTRACE_STACK_ENTRIES	8
 
 struct stack_entry {
+	struct trace_entry	ent;
 	unsigned long		caller[FTRACE_STACK_ENTRIES];
 };
 
 /*
- * The trace entry - the most basic unit of tracing. This is what
- * is printed in the end as a single line in the trace output, such as:
- *
- *     bash-15816 [01]   235.197585: idle_cpu <- irq_enter
+ * ftrace_printk entry:
  */
-struct trace_entry {
-	char			type;
-	char			cpu;
-	char			flags;
-	char			preempt_count;
-	int			pid;
-	cycle_t			t;
-	union {
-		struct ftrace_entry		fn;
-		struct ctx_switch_entry		ctx;
-		struct special_entry		special;
-		struct stack_entry		stack;
-		struct mmiotrace_rw		mmiorw;
-		struct mmiotrace_map		mmiomap;
-	};
+struct print_entry {
+	struct trace_entry	ent;
+	unsigned long		ip;
+	char			buf[];
+};
+
+#define TRACE_OLD_SIZE		88
+
+struct trace_field_cont {
+	unsigned char		type;
+	/* Temporary till we get rid of this completely */
+	char			buf[TRACE_OLD_SIZE - 1];
+};
+
+struct trace_mmiotrace_rw {
+	struct trace_entry	ent;
+	struct mmiotrace_rw	rw;
 };
 
-#define TRACE_ENTRY_SIZE	sizeof(struct trace_entry)
+struct trace_mmiotrace_map {
+	struct trace_entry	ent;
+	struct mmiotrace_map	map;
+};
+
+struct trace_boot {
+	struct trace_entry	ent;
+	struct boot_trace	initcall;
+};
+
+/*
+ * trace_flag_type is an enumeration that holds different
+ * states when a trace occurs. These are:
+ *  IRQS_OFF	- interrupts were disabled
+ *  NEED_RESCED - reschedule is requested
+ *  HARDIRQ	- inside an interrupt handler
+ *  SOFTIRQ	- inside a softirq handler
+ *  CONT	- multiple entries hold the trace item
+ */
+enum trace_flag_type {
+	TRACE_FLAG_IRQS_OFF		= 0x01,
+	TRACE_FLAG_NEED_RESCHED		= 0x02,
+	TRACE_FLAG_HARDIRQ		= 0x04,
+	TRACE_FLAG_SOFTIRQ		= 0x08,
+	TRACE_FLAG_CONT			= 0x10,
+};
+
+#define TRACE_BUF_SIZE		1024
 
 /*
  * The CPU trace array - it consists of thousands of trace entries
@@ -91,16 +142,9 @@ struct trace_entry {
  * the trace, etc.)
  */
 struct trace_array_cpu {
-	struct list_head	trace_pages;
 	atomic_t		disabled;
-	raw_spinlock_t		lock;
-	struct lock_class_key	lock_key;
 
 	/* these fields get copied into max-trace: */
-	unsigned		trace_head_idx;
-	unsigned		trace_tail_idx;
-	void			*trace_head; /* producer */
-	void			*trace_tail; /* consumer */
 	unsigned long		trace_idx;
 	unsigned long		overrun;
 	unsigned long		saved_latency;
@@ -124,6 +168,7 @@ struct trace_iterator;
  * They have on/off state as well:
  */
 struct trace_array {
+	struct ring_buffer	*buffer;
 	unsigned long		entries;
 	long			ctrl;
 	int			cpu;
@@ -132,6 +177,56 @@ struct trace_array {
 	struct trace_array_cpu	*data[NR_CPUS];
 };
 
+#define FTRACE_CMP_TYPE(var, type) \
+	__builtin_types_compatible_p(typeof(var), type *)
+
+#undef IF_ASSIGN
+#define IF_ASSIGN(var, entry, etype, id)		\
+	if (FTRACE_CMP_TYPE(var, etype)) {		\
+		var = (typeof(var))(entry);		\
+		WARN_ON(id && (entry)->type != id);	\
+		break;					\
+	}
+
+/* Will cause compile errors if type is not found. */
+extern void __ftrace_bad_type(void);
+
+/*
+ * The trace_assign_type is a verifier that the entry type is
+ * the same as the type being assigned. To add new types simply
+ * add a line with the following format:
+ *
+ * IF_ASSIGN(var, ent, type, id);
+ *
+ *  Where "type" is the trace type that includes the trace_entry
+ *  as the "ent" item. And "id" is the trace identifier that is
+ *  used in the trace_type enum.
+ *
+ *  If the type can have more than one id, then use zero.
+ */
+#define trace_assign_type(var, ent)					\
+	do {								\
+		IF_ASSIGN(var, ent, struct ftrace_entry, TRACE_FN);	\
+		IF_ASSIGN(var, ent, struct ctx_switch_entry, 0);	\
+		IF_ASSIGN(var, ent, struct trace_field_cont, TRACE_CONT); \
+		IF_ASSIGN(var, ent, struct stack_entry, TRACE_STACK);	\
+		IF_ASSIGN(var, ent, struct print_entry, TRACE_PRINT);	\
+		IF_ASSIGN(var, ent, struct special_entry, 0);		\
+		IF_ASSIGN(var, ent, struct trace_mmiotrace_rw,		\
+			  TRACE_MMIO_RW);				\
+		IF_ASSIGN(var, ent, struct trace_mmiotrace_map,		\
+			  TRACE_MMIO_MAP);				\
+		IF_ASSIGN(var, ent, struct trace_boot, TRACE_BOOT);	\
+		__ftrace_bad_type();					\
+	} while (0)
+
+/* Return values for print_line callback */
+enum print_line_t {
+	TRACE_TYPE_PARTIAL_LINE	= 0,	/* Retry after flushing the seq */
+	TRACE_TYPE_HANDLED	= 1,
+	TRACE_TYPE_UNHANDLED	= 2	/* Relay to other output functions */
+};
+
 /*
  * A specific tracer, represented by methods that operate on a trace array:
  */
@@ -152,7 +247,7 @@ struct tracer {
 	int			(*selftest)(struct tracer *trace,
 					    struct trace_array *tr);
 #endif
-	int			(*print_line)(struct trace_iterator *iter);
+	enum print_line_t	(*print_line)(struct trace_iterator *iter);
 	struct tracer		*next;
 	int			print_max;
 };
@@ -171,57 +266,58 @@ struct trace_iterator {
 	struct trace_array	*tr;
 	struct tracer		*trace;
 	void			*private;
-	long			last_overrun[NR_CPUS];
-	long			overrun[NR_CPUS];
+	struct ring_buffer_iter	*buffer_iter[NR_CPUS];
 
 	/* The below is zeroed out in pipe_read */
 	struct trace_seq	seq;
 	struct trace_entry	*ent;
 	int			cpu;
-
-	struct trace_entry	*prev_ent;
-	int			prev_cpu;
+	u64			ts;
 
 	unsigned long		iter_flags;
 	loff_t			pos;
-	unsigned long		next_idx[NR_CPUS];
-	struct list_head	*next_page[NR_CPUS];
-	unsigned		next_page_idx[NR_CPUS];
 	long			idx;
 };
 
-void tracing_reset(struct trace_array_cpu *data);
+void trace_wake_up(void);
+void tracing_reset(struct trace_array *tr, int cpu);
 int tracing_open_generic(struct inode *inode, struct file *filp);
 struct dentry *tracing_init_dentry(void);
 void init_tracer_sysprof_debugfs(struct dentry *d_tracer);
 
+struct trace_entry *tracing_get_trace_entry(struct trace_array *tr,
+						struct trace_array_cpu *data);
+void tracing_generic_entry_update(struct trace_entry *entry,
+				  unsigned long flags,
+				  int pc);
+
 void ftrace(struct trace_array *tr,
 			    struct trace_array_cpu *data,
 			    unsigned long ip,
 			    unsigned long parent_ip,
-			    unsigned long flags);
+			    unsigned long flags, int pc);
 void tracing_sched_switch_trace(struct trace_array *tr,
 				struct trace_array_cpu *data,
 				struct task_struct *prev,
 				struct task_struct *next,
-				unsigned long flags);
+				unsigned long flags, int pc);
 void tracing_record_cmdline(struct task_struct *tsk);
 
 void tracing_sched_wakeup_trace(struct trace_array *tr,
 				struct trace_array_cpu *data,
 				struct task_struct *wakee,
 				struct task_struct *cur,
-				unsigned long flags);
+				unsigned long flags, int pc);
 void trace_special(struct trace_array *tr,
 		   struct trace_array_cpu *data,
 		   unsigned long arg1,
 		   unsigned long arg2,
-		   unsigned long arg3);
+		   unsigned long arg3, int pc);
 void trace_function(struct trace_array *tr,
 		    struct trace_array_cpu *data,
 		    unsigned long ip,
 		    unsigned long parent_ip,
-		    unsigned long flags);
+		    unsigned long flags, int pc);
 
 void tracing_start_cmdline_record(void);
 void tracing_stop_cmdline_record(void);
@@ -268,51 +364,33 @@ extern unsigned long ftrace_update_tot_cnt;
 extern int DYN_FTRACE_TEST_NAME(void);
 #endif
 
-#ifdef CONFIG_MMIOTRACE
-extern void __trace_mmiotrace_rw(struct trace_array *tr,
-				struct trace_array_cpu *data,
-				struct mmiotrace_rw *rw);
-extern void __trace_mmiotrace_map(struct trace_array *tr,
-				struct trace_array_cpu *data,
-				struct mmiotrace_map *map);
-#endif
-
 #ifdef CONFIG_FTRACE_STARTUP_TEST
-#ifdef CONFIG_FTRACE
 extern int trace_selftest_startup_function(struct tracer *trace,
 					   struct trace_array *tr);
-#endif
-#ifdef CONFIG_IRQSOFF_TRACER
 extern int trace_selftest_startup_irqsoff(struct tracer *trace,
 					  struct trace_array *tr);
-#endif
-#ifdef CONFIG_PREEMPT_TRACER
 extern int trace_selftest_startup_preemptoff(struct tracer *trace,
 					     struct trace_array *tr);
-#endif
-#if defined(CONFIG_IRQSOFF_TRACER) && defined(CONFIG_PREEMPT_TRACER)
 extern int trace_selftest_startup_preemptirqsoff(struct tracer *trace,
 						 struct trace_array *tr);
-#endif
-#ifdef CONFIG_SCHED_TRACER
 extern int trace_selftest_startup_wakeup(struct tracer *trace,
 					 struct trace_array *tr);
-#endif
-#ifdef CONFIG_CONTEXT_SWITCH_TRACER
+extern int trace_selftest_startup_nop(struct tracer *trace,
+					 struct trace_array *tr);
 extern int trace_selftest_startup_sched_switch(struct tracer *trace,
 					       struct trace_array *tr);
-#endif
-#ifdef CONFIG_SYSPROF_TRACER
 extern int trace_selftest_startup_sysprof(struct tracer *trace,
 					       struct trace_array *tr);
-#endif
 #endif /* CONFIG_FTRACE_STARTUP_TEST */
 
 extern void *head_page(struct trace_array_cpu *data);
 extern int trace_seq_printf(struct trace_seq *s, const char *fmt, ...);
+extern void trace_seq_print_cont(struct trace_seq *s,
+				 struct trace_iterator *iter);
 extern ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf,
 				 size_t cnt);
 extern long ns2usecs(cycle_t nsec);
+extern int trace_vprintk(unsigned long ip, const char *fmt, va_list args);
 
 extern unsigned long trace_flags;
 
@@ -334,6 +412,9 @@ enum trace_iterator_flags {
 	TRACE_ITER_BLOCK		= 0x80,
 	TRACE_ITER_STACKTRACE		= 0x100,
 	TRACE_ITER_SCHED_TREE		= 0x200,
+	TRACE_ITER_PRINTK		= 0x400,
 };
 
+extern struct tracer nop_trace;
+
 #endif /* _LINUX_KERNEL_TRACE_H */

kernel/trace/trace_boot.c

@@ -0,0 +1,126 @@
+/*
+ * ring buffer based initcalls tracer
+ *
+ * Copyright (C) 2008 Frederic Weisbecker <fweisbec@gmail.com>
+ *
+ */
+
+#include <linux/init.h>
+#include <linux/debugfs.h>
+#include <linux/ftrace.h>
+#include <linux/kallsyms.h>
+
+#include "trace.h"
+
+static struct trace_array *boot_trace;
+static int trace_boot_enabled;
+
+
+/* Should be started after do_pre_smp_initcalls() in init/main.c */
+void start_boot_trace(void)
+{
+	trace_boot_enabled = 1;
+}
+
+void stop_boot_trace(void)
+{
+	trace_boot_enabled = 0;
+}
+
+void reset_boot_trace(struct trace_array *tr)
+{
+	stop_boot_trace();
+}
+
+static void boot_trace_init(struct trace_array *tr)
+{
+	int cpu;
+	boot_trace = tr;
+
+	trace_boot_enabled = 0;
+
+	for_each_cpu_mask(cpu, cpu_possible_map)
+		tracing_reset(tr, cpu);
+}
+
+static void boot_trace_ctrl_update(struct trace_array *tr)
+{
+	if (tr->ctrl)
+		start_boot_trace();
+	else
+		stop_boot_trace();
+}
+
+static enum print_line_t initcall_print_line(struct trace_iterator *iter)
+{
+	int ret;
+	struct trace_entry *entry = iter->ent;
+	struct trace_boot *field = (struct trace_boot *)entry;
+	struct boot_trace *it = &field->initcall;
+	struct trace_seq *s = &iter->seq;
+	struct timespec calltime = ktime_to_timespec(it->calltime);
+	struct timespec rettime = ktime_to_timespec(it->rettime);
+
+	if (entry->type == TRACE_BOOT) {
+		ret = trace_seq_printf(s, "[%5ld.%09ld] calling  %s @ %i\n",
+					  calltime.tv_sec,
+					  calltime.tv_nsec,
+					  it->func, it->caller);
+		if (!ret)
+			return TRACE_TYPE_PARTIAL_LINE;
+
+		ret = trace_seq_printf(s, "[%5ld.%09ld] initcall %s "
+					  "returned %d after %lld msecs\n",
+					  rettime.tv_sec,
+					  rettime.tv_nsec,
+					  it->func, it->result, it->duration);
+
+		if (!ret)
+			return TRACE_TYPE_PARTIAL_LINE;
+		return TRACE_TYPE_HANDLED;
+	}
+	return TRACE_TYPE_UNHANDLED;
+}
+
+struct tracer boot_tracer __read_mostly =
+{
+	.name		= "initcall",
+	.init		= boot_trace_init,
+	.reset		= reset_boot_trace,
+	.ctrl_update	= boot_trace_ctrl_update,
+	.print_line	= initcall_print_line,
+};
+
+void trace_boot(struct boot_trace *it, initcall_t fn)
+{
+	struct ring_buffer_event *event;
+	struct trace_boot *entry;
+	struct trace_array_cpu *data;
+	unsigned long irq_flags;
+	struct trace_array *tr = boot_trace;
+
+	if (!trace_boot_enabled)
+		return;
+
+	/* Get its name now since this function could
+	 * disappear because it is in the .init section.
+	 */
+	sprint_symbol(it->func, (unsigned long)fn);
+	preempt_disable();
+	data = tr->data[smp_processor_id()];
+
+	event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
+					 &irq_flags);
+	if (!event)
+		goto out;
+	entry	= ring_buffer_event_data(event);
+	tracing_generic_entry_update(&entry->ent, 0, 0);
+	entry->ent.type = TRACE_BOOT;
+	entry->initcall = *it;
+	ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
+
+	trace_wake_up();
+
+ out:
+	preempt_enable();
+}

kernel/trace/trace_functions.c

@@ -23,7 +23,7 @@ static void function_reset(struct trace_array *tr)
 	tr->time_start = ftrace_now(tr->cpu);
 
 	for_each_online_cpu(cpu)
-		tracing_reset(tr->data[cpu]);
+		tracing_reset(tr, cpu);
 }
 
 static void start_function_trace(struct trace_array *tr)

kernel/trace/trace_irqsoff.c

@@ -95,7 +95,7 @@ irqsoff_tracer_call(unsigned long ip, unsigned long parent_ip)
 	disabled = atomic_inc_return(&data->disabled);
 
 	if (likely(disabled == 1))
-		trace_function(tr, data, ip, parent_ip, flags);
+		trace_function(tr, data, ip, parent_ip, flags, preempt_count());
 
 	atomic_dec(&data->disabled);
 }
@@ -130,6 +130,7 @@ check_critical_timing(struct trace_array *tr,
 	unsigned long latency, t0, t1;
 	cycle_t T0, T1, delta;
 	unsigned long flags;
+	int pc;
 
 	/*
 	 * usecs conversion is slow so we try to delay the conversion
@@ -141,6 +142,8 @@ check_critical_timing(struct trace_array *tr,
 
 	local_save_flags(flags);
 
+	pc = preempt_count();
+
 	if (!report_latency(delta))
 		goto out;
 
@@ -150,7 +153,7 @@ check_critical_timing(struct trace_array *tr,
 	if (!report_latency(delta))
 		goto out_unlock;
 
-	trace_function(tr, data, CALLER_ADDR0, parent_ip, flags);
+	trace_function(tr, data, CALLER_ADDR0, parent_ip, flags, pc);
 
 	latency = nsecs_to_usecs(delta);
 
@@ -173,8 +176,8 @@ out_unlock:
 out:
 	data->critical_sequence = max_sequence;
 	data->preempt_timestamp = ftrace_now(cpu);
-	tracing_reset(data);
-	trace_function(tr, data, CALLER_ADDR0, parent_ip, flags);
+	tracing_reset(tr, cpu);
+	trace_function(tr, data, CALLER_ADDR0, parent_ip, flags, pc);
 }
 
 static inline void
@@ -203,11 +206,11 @@ start_critical_timing(unsigned long ip, unsigned long parent_ip)
 	data->critical_sequence = max_sequence;
 	data->preempt_timestamp = ftrace_now(cpu);
 	data->critical_start = parent_ip ? : ip;
-	tracing_reset(data);
+	tracing_reset(tr, cpu);
 
 	local_save_flags(flags);
 
-	trace_function(tr, data, ip, parent_ip, flags);
+	trace_function(tr, data, ip, parent_ip, flags, preempt_count());
 
 	per_cpu(tracing_cpu, cpu) = 1;
 
@@ -234,14 +237,14 @@ stop_critical_timing(unsigned long ip, unsigned long parent_ip)
 
 	data = tr->data[cpu];
 
-	if (unlikely(!data) || unlikely(!head_page(data)) ||
+	if (unlikely(!data) ||
 	    !data->critical_start || atomic_read(&data->disabled))
 		return;
 
 	atomic_inc(&data->disabled);
 
 	local_save_flags(flags);
-	trace_function(tr, data, ip, parent_ip, flags);
+	trace_function(tr, data, ip, parent_ip, flags, preempt_count());
 	check_critical_timing(tr, data, parent_ip ? : ip, cpu);
 	data->critical_start = 0;
 	atomic_dec(&data->disabled);

kernel/trace/trace_mmiotrace.c

@@ -27,7 +27,7 @@ static void mmio_reset_data(struct trace_array *tr)
 	tr->time_start = ftrace_now(tr->cpu);
 
 	for_each_online_cpu(cpu)
-		tracing_reset(tr->data[cpu]);
+		tracing_reset(tr, cpu);
 }
 
 static void mmio_trace_init(struct trace_array *tr)
@@ -130,10 +130,14 @@ static unsigned long count_overruns(struct trace_iterator *iter)
 {
 	int cpu;
 	unsigned long cnt = 0;
+/* FIXME: */
+#if 0
 	for_each_online_cpu(cpu) {
 		cnt += iter->overrun[cpu];
 		iter->overrun[cpu] = 0;
 	}
+#endif
+	(void)cpu;
 	return cnt;
 }
 
@@ -171,17 +175,21 @@ print_out:
 	return (ret == -EBUSY) ? 0 : ret;
 }
 
-static int mmio_print_rw(struct trace_iterator *iter)
+static enum print_line_t mmio_print_rw(struct trace_iterator *iter)
 {
 	struct trace_entry *entry = iter->ent;
-	struct mmiotrace_rw *rw	= &entry->mmiorw;
+	struct trace_mmiotrace_rw *field;
+	struct mmiotrace_rw *rw;
 	struct trace_seq *s	= &iter->seq;
-	unsigned long long t	= ns2usecs(entry->t);
+	unsigned long long t	= ns2usecs(iter->ts);
 	unsigned long usec_rem	= do_div(t, 1000000ULL);
 	unsigned secs		= (unsigned long)t;
 	int ret = 1;
 
-	switch (entry->mmiorw.opcode) {
+	trace_assign_type(field, entry);
+	rw = &field->rw;
+
+	switch (rw->opcode) {
 	case MMIO_READ:
 		ret = trace_seq_printf(s,
 			"R %d %lu.%06lu %d 0x%llx 0x%lx 0x%lx %d\n",
@@ -209,21 +217,25 @@ static int mmio_print_rw(struct trace_iterator *iter)
 		break;
 	}
 	if (ret)
-		return 1;
-	return 0;
+		return TRACE_TYPE_HANDLED;
+	return TRACE_TYPE_PARTIAL_LINE;
 }
 
-static int mmio_print_map(struct trace_iterator *iter)
+static enum print_line_t mmio_print_map(struct trace_iterator *iter)
 {
 	struct trace_entry *entry = iter->ent;
-	struct mmiotrace_map *m	= &entry->mmiomap;
+	struct trace_mmiotrace_map *field;
+	struct mmiotrace_map *m;
 	struct trace_seq *s	= &iter->seq;
-	unsigned long long t	= ns2usecs(entry->t);
+	unsigned long long t	= ns2usecs(iter->ts);
 	unsigned long usec_rem	= do_div(t, 1000000ULL);
 	unsigned secs		= (unsigned long)t;
-	int ret = 1;
+	int ret;
 
-	switch (entry->mmiorw.opcode) {
+	trace_assign_type(field, entry);
+	m = &field->map;
+
+	switch (m->opcode) {
 	case MMIO_PROBE:
 		ret = trace_seq_printf(s,
 			"MAP %lu.%06lu %d 0x%llx 0x%lx 0x%lx 0x%lx %d\n",
@@ -241,20 +253,43 @@ static int mmio_print_map(struct trace_iterator *iter)
 		break;
 	}
 	if (ret)
-		return 1;
-	return 0;
+		return TRACE_TYPE_HANDLED;
+	return TRACE_TYPE_PARTIAL_LINE;
+}
+
+static enum print_line_t mmio_print_mark(struct trace_iterator *iter)
+{
+	struct trace_entry *entry = iter->ent;
+	struct print_entry *print = (struct print_entry *)entry;
+	const char *msg		= print->buf;
+	struct trace_seq *s	= &iter->seq;
+	unsigned long long t	= ns2usecs(iter->ts);
+	unsigned long usec_rem	= do_div(t, 1000000ULL);
+	unsigned secs		= (unsigned long)t;
+	int ret;
+
+	/* The trailing newline must be in the message. */
+	ret = trace_seq_printf(s, "MARK %lu.%06lu %s", secs, usec_rem, msg);
+	if (!ret)
+		return TRACE_TYPE_PARTIAL_LINE;
+
+	if (entry->flags & TRACE_FLAG_CONT)
+		trace_seq_print_cont(s, iter);
+
+	return TRACE_TYPE_HANDLED;
 }
 
-/* return 0 to abort printing without consuming current entry in pipe mode */
-static int mmio_print_line(struct trace_iterator *iter)
+static enum print_line_t mmio_print_line(struct trace_iterator *iter)
 {
 	switch (iter->ent->type) {
 	case TRACE_MMIO_RW:
 		return mmio_print_rw(iter);
 	case TRACE_MMIO_MAP:
 		return mmio_print_map(iter);
+	case TRACE_PRINT:
+		return mmio_print_mark(iter);
 	default:
-		return 1; /* ignore unknown entries */
+		return TRACE_TYPE_HANDLED; /* ignore unknown entries */
 	}
 }
 
@@ -276,6 +311,27 @@ __init static int init_mmio_trace(void)
 }
 device_initcall(init_mmio_trace);
 
+static void __trace_mmiotrace_rw(struct trace_array *tr,
+				struct trace_array_cpu *data,
+				struct mmiotrace_rw *rw)
+{
+	struct ring_buffer_event *event;
+	struct trace_mmiotrace_rw *entry;
+	unsigned long irq_flags;
+
+	event	= ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
+					   &irq_flags);
+	if (!event)
+		return;
+	entry	= ring_buffer_event_data(event);
+	tracing_generic_entry_update(&entry->ent, 0, preempt_count());
+	entry->ent.type			= TRACE_MMIO_RW;
+	entry->rw			= *rw;
+	ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
+
+	trace_wake_up();
+}
+
 void mmio_trace_rw(struct mmiotrace_rw *rw)
 {
 	struct trace_array *tr = mmio_trace_array;
@@ -283,6 +339,27 @@ void mmio_trace_rw(struct mmiotrace_rw *rw)
 	__trace_mmiotrace_rw(tr, data, rw);
 }
 
+static void __trace_mmiotrace_map(struct trace_array *tr,
+				struct trace_array_cpu *data,
+				struct mmiotrace_map *map)
+{
+	struct ring_buffer_event *event;
+	struct trace_mmiotrace_map *entry;
+	unsigned long irq_flags;
+
+	event	= ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
+					   &irq_flags);
+	if (!event)
+		return;
+	entry	= ring_buffer_event_data(event);
+	tracing_generic_entry_update(&entry->ent, 0, preempt_count());
+	entry->ent.type			= TRACE_MMIO_MAP;
+	entry->map			= *map;
+	ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
+
+	trace_wake_up();
+}
+
 void mmio_trace_mapping(struct mmiotrace_map *map)
 {
 	struct trace_array *tr = mmio_trace_array;
@@ -293,3 +370,8 @@ void mmio_trace_mapping(struct mmiotrace_map *map)
 	__trace_mmiotrace_map(tr, data, map);
 	preempt_enable();
 }
+
+int mmio_trace_printk(const char *fmt, va_list args)
+{
+	return trace_vprintk(0, fmt, args);
+}

kernel/trace/trace_nop.c

@@ -0,0 +1,64 @@
+/*
+ * nop tracer
+ *
+ * Copyright (C) 2008 Steven Noonan <steven@uplinklabs.net>
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/debugfs.h>
+#include <linux/ftrace.h>
+
+#include "trace.h"
+
+static struct trace_array	*ctx_trace;
+
+static void start_nop_trace(struct trace_array *tr)
+{
+	/* Nothing to do! */
+}
+
+static void stop_nop_trace(struct trace_array *tr)
+{
+	/* Nothing to do! */
+}
+
+static void nop_trace_init(struct trace_array *tr)
+{
+	int cpu;
+	ctx_trace = tr;
+
+	for_each_online_cpu(cpu)
+		tracing_reset(tr, cpu);
+
+	if (tr->ctrl)
+		start_nop_trace(tr);
+}
+
+static void nop_trace_reset(struct trace_array *tr)
+{
+	if (tr->ctrl)
+		stop_nop_trace(tr);
+}
+
+static void nop_trace_ctrl_update(struct trace_array *tr)
+{
+	/* When starting a new trace, reset the buffers */
+	if (tr->ctrl)
+		start_nop_trace(tr);
+	else
+		stop_nop_trace(tr);
+}
+
+struct tracer nop_trace __read_mostly =
+{
+	.name		= "nop",
+	.init		= nop_trace_init,
+	.reset		= nop_trace_reset,
+	.ctrl_update	= nop_trace_ctrl_update,
+#ifdef CONFIG_FTRACE_SELFTEST
+	.selftest	= trace_selftest_startup_nop,
+#endif
+};
+

kernel/trace/trace_sched_switch.c

@@ -9,8 +9,8 @@
 #include <linux/debugfs.h>
 #include <linux/kallsyms.h>
 #include <linux/uaccess.h>
-#include <linux/marker.h>
 #include <linux/ftrace.h>
+#include <trace/sched.h>
 
 #include "trace.h"
 
@@ -19,15 +19,16 @@ static int __read_mostly	tracer_enabled;
 static atomic_t			sched_ref;
 
 static void
-sched_switch_func(void *private, void *__rq, struct task_struct *prev,
+probe_sched_switch(struct rq *__rq, struct task_struct *prev,
 			struct task_struct *next)
 {
-	struct trace_array **ptr = private;
-	struct trace_array *tr = *ptr;
 	struct trace_array_cpu *data;
 	unsigned long flags;
-	long disabled;
 	int cpu;
+	int pc;
+
+	if (!atomic_read(&sched_ref))
+		return;
 
 	tracing_record_cmdline(prev);
 	tracing_record_cmdline(next);
@@ -35,97 +36,41 @@ sched_switch_func(void *private, void *__rq, struct task_struct *prev,
 	if (!tracer_enabled)
 		return;
 
+	pc = preempt_count();
 	local_irq_save(flags);
 	cpu = raw_smp_processor_id();
-	data = tr->data[cpu];
-	disabled = atomic_inc_return(&data->disabled);
+	data = ctx_trace->data[cpu];
 
-	if (likely(disabled == 1))
-		tracing_sched_switch_trace(tr, data, prev, next, flags);
+	if (likely(!atomic_read(&data->disabled)))
+		tracing_sched_switch_trace(ctx_trace, data, prev, next, flags, pc);
 
-	atomic_dec(&data->disabled);
 	local_irq_restore(flags);
 }
 
-static notrace void
-sched_switch_callback(void *probe_data, void *call_data,
-		      const char *format, va_list *args)
-{
-	struct task_struct *prev;
-	struct task_struct *next;
-	struct rq *__rq;
-
-	if (!atomic_read(&sched_ref))
-		return;
-
-	/* skip prev_pid %d next_pid %d prev_state %ld */
-	(void)va_arg(*args, int);
-	(void)va_arg(*args, int);
-	(void)va_arg(*args, long);
-	__rq = va_arg(*args, typeof(__rq));
-	prev = va_arg(*args, typeof(prev));
-	next = va_arg(*args, typeof(next));
-
-	/*
-	 * If tracer_switch_func only points to the local
-	 * switch func, it still needs the ptr passed to it.
-	 */
-	sched_switch_func(probe_data, __rq, prev, next);
-}
-
 static void
-wakeup_func(void *private, void *__rq, struct task_struct *wakee, struct
-			task_struct *curr)
+probe_sched_wakeup(struct rq *__rq, struct task_struct *wakee)
 {
-	struct trace_array **ptr = private;
-	struct trace_array *tr = *ptr;
 	struct trace_array_cpu *data;
 	unsigned long flags;
-	long disabled;
-	int cpu;
+	int cpu, pc;
 
-	if (!tracer_enabled)
+	if (!likely(tracer_enabled))
 		return;
 
-	tracing_record_cmdline(curr);
+	pc = preempt_count();
+	tracing_record_cmdline(current);
 
 	local_irq_save(flags);
 	cpu = raw_smp_processor_id();
-	data = tr->data[cpu];
-	disabled = atomic_inc_return(&data->disabled);
+	data = ctx_trace->data[cpu];
 
-	if (likely(disabled == 1))
-		tracing_sched_wakeup_trace(tr, data, wakee, curr, flags);
+	if (likely(!atomic_read(&data->disabled)))
+		tracing_sched_wakeup_trace(ctx_trace, data, wakee, current,
+					   flags, pc);
 
-	atomic_dec(&data->disabled);
 	local_irq_restore(flags);
 }
 
-static notrace void
-wake_up_callback(void *probe_data, void *call_data,
-		 const char *format, va_list *args)
-{
-	struct task_struct *curr;
-	struct task_struct *task;
-	struct rq *__rq;
-
-	if (likely(!tracer_enabled))
-		return;
-
-	/* Skip pid %d state %ld */
-	(void)va_arg(*args, int);
-	(void)va_arg(*args, long);
-	/* now get the meat: "rq %p task %p rq->curr %p" */
-	__rq = va_arg(*args, typeof(__rq));
-	task = va_arg(*args, typeof(task));
-	curr = va_arg(*args, typeof(curr));
-
-	tracing_record_cmdline(task);
-	tracing_record_cmdline(curr);
-
-	wakeup_func(probe_data, __rq, task, curr);
-}
-
 static void sched_switch_reset(struct trace_array *tr)
 {
 	int cpu;
@@ -133,67 +78,47 @@ static void sched_switch_reset(struct trace_array *tr)
 	tr->time_start = ftrace_now(tr->cpu);
 
 	for_each_online_cpu(cpu)
-		tracing_reset(tr->data[cpu]);
+		tracing_reset(tr, cpu);
 }
 
 static int tracing_sched_register(void)
 {
 	int ret;
 
-	ret = marker_probe_register("kernel_sched_wakeup",
-			"pid %d state %ld ## rq %p task %p rq->curr %p",
-			wake_up_callback,
-			&ctx_trace);
+	ret = register_trace_sched_wakeup(probe_sched_wakeup);
 	if (ret) {
-		pr_info("wakeup trace: Couldn't add marker"
+		pr_info("wakeup trace: Couldn't activate tracepoint"
 			" probe to kernel_sched_wakeup\n");
 		return ret;
 	}
 
-	ret = marker_probe_register("kernel_sched_wakeup_new",
-			"pid %d state %ld ## rq %p task %p rq->curr %p",
-			wake_up_callback,
-			&ctx_trace);
+	ret = register_trace_sched_wakeup_new(probe_sched_wakeup);
 	if (ret) {
-		pr_info("wakeup trace: Couldn't add marker"
+		pr_info("wakeup trace: Couldn't activate tracepoint"
 			" probe to kernel_sched_wakeup_new\n");
 		goto fail_deprobe;
 	}
 
-	ret = marker_probe_register("kernel_sched_schedule",
-		"prev_pid %d next_pid %d prev_state %ld "
-		"## rq %p prev %p next %p",
-		sched_switch_callback,
-		&ctx_trace);
+	ret = register_trace_sched_switch(probe_sched_switch);
 	if (ret) {
-		pr_info("sched trace: Couldn't add marker"
+		pr_info("sched trace: Couldn't activate tracepoint"
 			" probe to kernel_sched_schedule\n");
 		goto fail_deprobe_wake_new;
 	}
 
 	return ret;
 fail_deprobe_wake_new:
-	marker_probe_unregister("kernel_sched_wakeup_new",
-				wake_up_callback,
-				&ctx_trace);
+	unregister_trace_sched_wakeup_new(probe_sched_wakeup);
 fail_deprobe:
-	marker_probe_unregister("kernel_sched_wakeup",
-				wake_up_callback,
-				&ctx_trace);
+	unregister_trace_sched_wakeup(probe_sched_wakeup);
 	return ret;
 }
 
 static void tracing_sched_unregister(void)
 {
-	marker_probe_unregister("kernel_sched_schedule",
-				sched_switch_callback,
-				&ctx_trace);
-	marker_probe_unregister("kernel_sched_wakeup_new",
-				wake_up_callback,
-				&ctx_trace);
-	marker_probe_unregister("kernel_sched_wakeup",
-				wake_up_callback,
-				&ctx_trace);
+	unregister_trace_sched_switch(probe_sched_switch);
+	unregister_trace_sched_wakeup_new(probe_sched_wakeup);
+	unregister_trace_sched_wakeup(probe_sched_wakeup);
 }
 
 static void tracing_start_sched_switch(void)

kernel/trace/trace_sched_wakeup.c

@@ -15,7 +15,7 @@
 #include <linux/kallsyms.h>
 #include <linux/uaccess.h>
 #include <linux/ftrace.h>
-#include <linux/marker.h>
+#include <trace/sched.h>
 
 #include "trace.h"
 
@@ -44,10 +44,12 @@ wakeup_tracer_call(unsigned long ip, unsigned long parent_ip)
 	long disabled;
 	int resched;
 	int cpu;
+	int pc;
 
 	if (likely(!wakeup_task))
 		return;
 
+	pc = preempt_count();
 	resched = need_resched();
 	preempt_disable_notrace();
 
@@ -70,7 +72,7 @@ wakeup_tracer_call(unsigned long ip, unsigned long parent_ip)
 	if (task_cpu(wakeup_task) != cpu)
 		goto unlock;
 
-	trace_function(tr, data, ip, parent_ip, flags);
+	trace_function(tr, data, ip, parent_ip, flags, pc);
 
  unlock:
 	__raw_spin_unlock(&wakeup_lock);
@@ -112,17 +114,18 @@ static int report_latency(cycle_t delta)
 }
 
 static void notrace
-wakeup_sched_switch(void *private, void *rq, struct task_struct *prev,
+probe_wakeup_sched_switch(struct rq *rq, struct task_struct *prev,
 	struct task_struct *next)
 {
 	unsigned long latency = 0, t0 = 0, t1 = 0;
-	struct trace_array **ptr = private;
-	struct trace_array *tr = *ptr;
 	struct trace_array_cpu *data;
 	cycle_t T0, T1, delta;
 	unsigned long flags;
 	long disabled;
 	int cpu;
+	int pc;
+
+	tracing_record_cmdline(prev);
 
 	if (unlikely(!tracer_enabled))
 		return;
@@ -139,12 +142,14 @@ wakeup_sched_switch(void *private, void *rq, struct task_struct *prev,
 	if (next != wakeup_task)
 		return;
 
+	pc = preempt_count();
+
 	/* The task we are waiting for is waking up */
-	data = tr->data[wakeup_cpu];
+	data = wakeup_trace->data[wakeup_cpu];
 
 	/* disable local data, not wakeup_cpu data */
 	cpu = raw_smp_processor_id();
-	disabled = atomic_inc_return(&tr->data[cpu]->disabled);
+	disabled = atomic_inc_return(&wakeup_trace->data[cpu]->disabled);
 	if (likely(disabled != 1))
 		goto out;
 
@@ -155,7 +160,7 @@ wakeup_sched_switch(void *private, void *rq, struct task_struct *prev,
 	if (unlikely(!tracer_enabled || next != wakeup_task))
 		goto out_unlock;
 
-	trace_function(tr, data, CALLER_ADDR1, CALLER_ADDR2, flags);
+	trace_function(wakeup_trace, data, CALLER_ADDR1, CALLER_ADDR2, flags, pc);
 
 	/*
 	 * usecs conversion is slow so we try to delay the conversion
@@ -174,39 +179,14 @@ wakeup_sched_switch(void *private, void *rq, struct task_struct *prev,
 	t0 = nsecs_to_usecs(T0);
 	t1 = nsecs_to_usecs(T1);
 
-	update_max_tr(tr, wakeup_task, wakeup_cpu);
+	update_max_tr(wakeup_trace, wakeup_task, wakeup_cpu);
 
 out_unlock:
-	__wakeup_reset(tr);
+	__wakeup_reset(wakeup_trace);
 	__raw_spin_unlock(&wakeup_lock);
 	local_irq_restore(flags);
 out:
-	atomic_dec(&tr->data[cpu]->disabled);
-}
-
-static notrace void
-sched_switch_callback(void *probe_data, void *call_data,
-		      const char *format, va_list *args)
-{
-	struct task_struct *prev;
-	struct task_struct *next;
-	struct rq *__rq;
-
-	/* skip prev_pid %d next_pid %d prev_state %ld */
-	(void)va_arg(*args, int);
-	(void)va_arg(*args, int);
-	(void)va_arg(*args, long);
-	__rq = va_arg(*args, typeof(__rq));
-	prev = va_arg(*args, typeof(prev));
-	next = va_arg(*args, typeof(next));
-
-	tracing_record_cmdline(prev);
-
-	/*
-	 * If tracer_switch_func only points to the local
-	 * switch func, it still needs the ptr passed to it.
-	 */
-	wakeup_sched_switch(probe_data, __rq, prev, next);
+	atomic_dec(&wakeup_trace->data[cpu]->disabled);
 }
 
 static void __wakeup_reset(struct trace_array *tr)
@@ -216,7 +196,7 @@ static void __wakeup_reset(struct trace_array *tr)
 
 	for_each_possible_cpu(cpu) {
 		data = tr->data[cpu];
-		tracing_reset(data);
+		tracing_reset(tr, cpu);
 	}
 
 	wakeup_cpu = -1;
@@ -240,19 +220,26 @@ static void wakeup_reset(struct trace_array *tr)
 }
 
 static void
-wakeup_check_start(struct trace_array *tr, struct task_struct *p,
-		   struct task_struct *curr)
+probe_wakeup(struct rq *rq, struct task_struct *p)
 {
 	int cpu = smp_processor_id();
 	unsigned long flags;
 	long disabled;
+	int pc;
+
+	if (likely(!tracer_enabled))
+		return;
+
+	tracing_record_cmdline(p);
+	tracing_record_cmdline(current);
 
 	if (likely(!rt_task(p)) ||
 			p->prio >= wakeup_prio ||
-			p->prio >= curr->prio)
+			p->prio >= current->prio)
 		return;
 
-	disabled = atomic_inc_return(&tr->data[cpu]->disabled);
+	pc = preempt_count();
+	disabled = atomic_inc_return(&wakeup_trace->data[cpu]->disabled);
 	if (unlikely(disabled != 1))
 		goto out;
 
@@ -264,7 +251,7 @@ wakeup_check_start(struct trace_array *tr, struct task_struct *p,
 		goto out_locked;
 
 	/* reset the trace */
-	__wakeup_reset(tr);
+	__wakeup_reset(wakeup_trace);
 
 	wakeup_cpu = task_cpu(p);
 	wakeup_prio = p->prio;
@@ -274,74 +261,37 @@ wakeup_check_start(struct trace_array *tr, struct task_struct *p,
 
 	local_save_flags(flags);
 
-	tr->data[wakeup_cpu]->preempt_timestamp = ftrace_now(cpu);
-	trace_function(tr, tr->data[wakeup_cpu],
-		       CALLER_ADDR1, CALLER_ADDR2, flags);
+	wakeup_trace->data[wakeup_cpu]->preempt_timestamp = ftrace_now(cpu);
+	trace_function(wakeup_trace, wakeup_trace->data[wakeup_cpu],
+		       CALLER_ADDR1, CALLER_ADDR2, flags, pc);
 
 out_locked:
 	__raw_spin_unlock(&wakeup_lock);
 out:
-	atomic_dec(&tr->data[cpu]->disabled);
-}
-
-static notrace void
-wake_up_callback(void *probe_data, void *call_data,
-		 const char *format, va_list *args)
-{
-	struct trace_array **ptr = probe_data;
-	struct trace_array *tr = *ptr;
-	struct task_struct *curr;
-	struct task_struct *task;
-	struct rq *__rq;
-
-	if (likely(!tracer_enabled))
-		return;
-
-	/* Skip pid %d state %ld */
-	(void)va_arg(*args, int);
-	(void)va_arg(*args, long);
-	/* now get the meat: "rq %p task %p rq->curr %p" */
-	__rq = va_arg(*args, typeof(__rq));
-	task = va_arg(*args, typeof(task));
-	curr = va_arg(*args, typeof(curr));
-
-	tracing_record_cmdline(task);
-	tracing_record_cmdline(curr);
-
-	wakeup_check_start(tr, task, curr);
+	atomic_dec(&wakeup_trace->data[cpu]->disabled);
 }
 
 static void start_wakeup_tracer(struct trace_array *tr)
 {
 	int ret;
 
-	ret = marker_probe_register("kernel_sched_wakeup",
-			"pid %d state %ld ## rq %p task %p rq->curr %p",
-			wake_up_callback,
-			&wakeup_trace);
+	ret = register_trace_sched_wakeup(probe_wakeup);
 	if (ret) {
-		pr_info("wakeup trace: Couldn't add marker"
+		pr_info("wakeup trace: Couldn't activate tracepoint"
 			" probe to kernel_sched_wakeup\n");
 		return;
 	}
 
-	ret = marker_probe_register("kernel_sched_wakeup_new",
-			"pid %d state %ld ## rq %p task %p rq->curr %p",
-			wake_up_callback,
-			&wakeup_trace);
+	ret = register_trace_sched_wakeup_new(probe_wakeup);
 	if (ret) {
-		pr_info("wakeup trace: Couldn't add marker"
+		pr_info("wakeup trace: Couldn't activate tracepoint"
 			" probe to kernel_sched_wakeup_new\n");
 		goto fail_deprobe;
 	}
 
-	ret = marker_probe_register("kernel_sched_schedule",
-		"prev_pid %d next_pid %d prev_state %ld "
-		"## rq %p prev %p next %p",
-		sched_switch_callback,
-		&wakeup_trace);
+	ret = register_trace_sched_switch(probe_wakeup_sched_switch);
 	if (ret) {
-		pr_info("sched trace: Couldn't add marker"
+		pr_info("sched trace: Couldn't activate tracepoint"
 			" probe to kernel_sched_schedule\n");
 		goto fail_deprobe_wake_new;
 	}
@@ -363,28 +313,18 @@ static void start_wakeup_tracer(struct trace_array *tr)
 
 	return;
 fail_deprobe_wake_new:
-	marker_probe_unregister("kernel_sched_wakeup_new",
-				wake_up_callback,
-				&wakeup_trace);
+	unregister_trace_sched_wakeup_new(probe_wakeup);
 fail_deprobe:
-	marker_probe_unregister("kernel_sched_wakeup",
-				wake_up_callback,
-				&wakeup_trace);
+	unregister_trace_sched_wakeup(probe_wakeup);
 }
 
 static void stop_wakeup_tracer(struct trace_array *tr)
 {
 	tracer_enabled = 0;
 	unregister_ftrace_function(&trace_ops);
-	marker_probe_unregister("kernel_sched_schedule",
-				sched_switch_callback,
-				&wakeup_trace);
-	marker_probe_unregister("kernel_sched_wakeup_new",
-				wake_up_callback,
-				&wakeup_trace);
-	marker_probe_unregister("kernel_sched_wakeup",
-				wake_up_callback,
-				&wakeup_trace);
+	unregister_trace_sched_switch(probe_wakeup_sched_switch);
+	unregister_trace_sched_wakeup_new(probe_wakeup);
+	unregister_trace_sched_wakeup(probe_wakeup);
 }
 
 static void wakeup_tracer_init(struct trace_array *tr)

kernel/trace/trace_selftest.c

@@ -9,65 +9,29 @@ static inline int trace_valid_entry(struct trace_entry *entry)
 	case TRACE_FN:
 	case TRACE_CTX:
 	case TRACE_WAKE:
+	case TRACE_CONT:
 	case TRACE_STACK:
+	case TRACE_PRINT:
 	case TRACE_SPECIAL:
 		return 1;
 	}
 	return 0;
 }
 
-static int
-trace_test_buffer_cpu(struct trace_array *tr, struct trace_array_cpu *data)
+static int trace_test_buffer_cpu(struct trace_array *tr, int cpu)
 {
-	struct trace_entry *entries;
-	struct page *page;
-	int idx = 0;
-	int i;
+	struct ring_buffer_event *event;
+	struct trace_entry *entry;
 
-	BUG_ON(list_empty(&data->trace_pages));
-	page = list_entry(data->trace_pages.next, struct page, lru);
-	entries = page_address(page);
+	while ((event = ring_buffer_consume(tr->buffer, cpu, NULL))) {
+		entry = ring_buffer_event_data(event);
 
-	check_pages(data);
-	if (head_page(data) != entries)
-		goto failed;
-
-	/*
-	 * The starting trace buffer always has valid elements,
-	 * if any element exists.
-	 */
-	entries = head_page(data);
-
-	for (i = 0; i < tr->entries; i++) {
-
-		if (i < data->trace_idx && !trace_valid_entry(&entries[idx])) {
+		if (!trace_valid_entry(entry)) {
 			printk(KERN_CONT ".. invalid entry %d ",
-				entries[idx].type);
+				entry->type);
 			goto failed;
 		}
-
-		idx++;
-		if (idx >= ENTRIES_PER_PAGE) {
-			page = virt_to_page(entries);
-			if (page->lru.next == &data->trace_pages) {
-				if (i != tr->entries - 1) {
-					printk(KERN_CONT ".. entries buffer mismatch");
-					goto failed;
-				}
-			} else {
-				page = list_entry(page->lru.next, struct page, lru);
-				entries = page_address(page);
-			}
-			idx = 0;
-		}
 	}
-
-	page = virt_to_page(entries);
-	if (page->lru.next != &data->trace_pages) {
-		printk(KERN_CONT ".. too many entries");
-		goto failed;
-	}
-
 	return 0;
 
  failed:
@@ -89,13 +53,11 @@ static int trace_test_buffer(struct trace_array *tr, unsigned long *count)
 	/* Don't allow flipping of max traces now */
 	raw_local_irq_save(flags);
 	__raw_spin_lock(&ftrace_max_lock);
-	for_each_possible_cpu(cpu) {
-		if (!head_page(tr->data[cpu]))
-			continue;
 
-		cnt += tr->data[cpu]->trace_idx;
+	cnt = ring_buffer_entries(tr->buffer);
 
-		ret = trace_test_buffer_cpu(tr, tr->data[cpu]);
+	for_each_possible_cpu(cpu) {
+		ret = trace_test_buffer_cpu(tr, cpu);
 		if (ret)
 			break;
 	}
@@ -120,11 +82,11 @@ int trace_selftest_startup_dynamic_tracing(struct tracer *trace,
 					   struct trace_array *tr,
 					   int (*func)(void))
 {
-	unsigned long count;
-	int ret;
 	int save_ftrace_enabled = ftrace_enabled;
 	int save_tracer_enabled = tracer_enabled;
+	unsigned long count;
 	char *func_name;
+	int ret;
 
 	/* The ftrace test PASSED */
 	printk(KERN_CONT "PASSED\n");
@@ -157,6 +119,7 @@ int trace_selftest_startup_dynamic_tracing(struct tracer *trace,
 	/* enable tracing */
 	tr->ctrl = 1;
 	trace->init(tr);
+
 	/* Sleep for a 1/10 of a second */
 	msleep(100);
 
@@ -212,10 +175,10 @@ int trace_selftest_startup_dynamic_tracing(struct tracer *trace,
 int
 trace_selftest_startup_function(struct tracer *trace, struct trace_array *tr)
 {
-	unsigned long count;
-	int ret;
 	int save_ftrace_enabled = ftrace_enabled;
 	int save_tracer_enabled = tracer_enabled;
+	unsigned long count;
+	int ret;
 
 	/* make sure msleep has been recorded */
 	msleep(1);
@@ -415,6 +378,15 @@ trace_selftest_startup_preemptirqsoff(struct tracer *trace, struct trace_array *
 }
 #endif /* CONFIG_IRQSOFF_TRACER && CONFIG_PREEMPT_TRACER */
 
+#ifdef CONFIG_NOP_TRACER
+int
+trace_selftest_startup_nop(struct tracer *trace, struct trace_array *tr)
+{
+	/* What could possibly go wrong? */
+	return 0;
+}
+#endif
+
 #ifdef CONFIG_SCHED_TRACER
 static int trace_wakeup_test_thread(void *data)
 {
@@ -486,6 +458,9 @@ trace_selftest_startup_wakeup(struct tracer *trace, struct trace_array *tr)
 
 	wake_up_process(p);
 
+	/* give a little time to let the thread wake up */
+	msleep(100);
+
 	/* stop the tracing. */
 	tr->ctrl = 0;
 	trace->ctrl_update(tr);

kernel/trace/trace_stack.c

@@ -0,0 +1,310 @@
+/*
+ * Copyright (C) 2008 Steven Rostedt <srostedt@redhat.com>
+ *
+ */
+#include <linux/stacktrace.h>
+#include <linux/kallsyms.h>
+#include <linux/seq_file.h>
+#include <linux/spinlock.h>
+#include <linux/uaccess.h>
+#include <linux/debugfs.h>
+#include <linux/ftrace.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/fs.h>
+#include "trace.h"
+
+#define STACK_TRACE_ENTRIES 500
+
+static unsigned long stack_dump_trace[STACK_TRACE_ENTRIES+1] =
+	 { [0 ... (STACK_TRACE_ENTRIES)] = ULONG_MAX };
+static unsigned stack_dump_index[STACK_TRACE_ENTRIES];
+
+static struct stack_trace max_stack_trace = {
+	.max_entries		= STACK_TRACE_ENTRIES,
+	.entries		= stack_dump_trace,
+};
+
+static unsigned long max_stack_size;
+static raw_spinlock_t max_stack_lock =
+	(raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED;
+
+static int stack_trace_disabled __read_mostly;
+static DEFINE_PER_CPU(int, trace_active);
+
+static inline void check_stack(void)
+{
+	unsigned long this_size, flags;
+	unsigned long *p, *top, *start;
+	int i;
+
+	this_size = ((unsigned long)&this_size) & (THREAD_SIZE-1);
+	this_size = THREAD_SIZE - this_size;
+
+	if (this_size <= max_stack_size)
+		return;
+
+	raw_local_irq_save(flags);
+	__raw_spin_lock(&max_stack_lock);
+
+	/* a race could have already updated it */
+	if (this_size <= max_stack_size)
+		goto out;
+
+	max_stack_size = this_size;
+
+	max_stack_trace.nr_entries	= 0;
+	max_stack_trace.skip		= 3;
+
+	save_stack_trace(&max_stack_trace);
+
+	/*
+	 * Now find where in the stack these are.
+	 */
+	i = 0;
+	start = &this_size;
+	top = (unsigned long *)
+		(((unsigned long)start & ~(THREAD_SIZE-1)) + THREAD_SIZE);
+
+	/*
+	 * Loop through all the entries. One of the entries may
+	 * for some reason be missed on the stack, so we may
+	 * have to account for them. If they are all there, this
+	 * loop will only happen once. This code only takes place
+	 * on a new max, so it is far from a fast path.
+	 */
+	while (i < max_stack_trace.nr_entries) {
+
+		stack_dump_index[i] = this_size;
+		p = start;
+
+		for (; p < top && i < max_stack_trace.nr_entries; p++) {
+			if (*p == stack_dump_trace[i]) {
+				this_size = stack_dump_index[i++] =
+					(top - p) * sizeof(unsigned long);
+				/* Start the search from here */
+				start = p + 1;
+			}
+		}
+
+		i++;
+	}
+
+ out:
+	__raw_spin_unlock(&max_stack_lock);
+	raw_local_irq_restore(flags);
+}
+
+static void
+stack_trace_call(unsigned long ip, unsigned long parent_ip)
+{
+	int cpu, resched;
+
+	if (unlikely(!ftrace_enabled || stack_trace_disabled))
+		return;
+
+	resched = need_resched();
+	preempt_disable_notrace();
+
+	cpu = raw_smp_processor_id();
+	/* no atomic needed, we only modify this variable by this cpu */
+	if (per_cpu(trace_active, cpu)++ != 0)
+		goto out;
+
+	check_stack();
+
+ out:
+	per_cpu(trace_active, cpu)--;
+	/* prevent recursion in schedule */
+	if (resched)
+		preempt_enable_no_resched_notrace();
+	else
+		preempt_enable_notrace();
+}
+
+static struct ftrace_ops trace_ops __read_mostly =
+{
+	.func = stack_trace_call,
+};
+
+static ssize_t
+stack_max_size_read(struct file *filp, char __user *ubuf,
+		    size_t count, loff_t *ppos)
+{
+	unsigned long *ptr = filp->private_data;
+	char buf[64];
+	int r;
+
+	r = snprintf(buf, sizeof(buf), "%ld\n", *ptr);
+	if (r > sizeof(buf))
+		r = sizeof(buf);
+	return simple_read_from_buffer(ubuf, count, ppos, buf, r);
+}
+
+static ssize_t
+stack_max_size_write(struct file *filp, const char __user *ubuf,
+		     size_t count, loff_t *ppos)
+{
+	long *ptr = filp->private_data;
+	unsigned long val, flags;
+	char buf[64];
+	int ret;
+
+	if (count >= sizeof(buf))
+		return -EINVAL;
+
+	if (copy_from_user(&buf, ubuf, count))
+		return -EFAULT;
+
+	buf[count] = 0;
+
+	ret = strict_strtoul(buf, 10, &val);
+	if (ret < 0)
+		return ret;
+
+	raw_local_irq_save(flags);
+	__raw_spin_lock(&max_stack_lock);
+	*ptr = val;
+	__raw_spin_unlock(&max_stack_lock);
+	raw_local_irq_restore(flags);
+
+	return count;
+}
+
+static struct file_operations stack_max_size_fops = {
+	.open		= tracing_open_generic,
+	.read		= stack_max_size_read,
+	.write		= stack_max_size_write,
+};
+
+static void *
+t_next(struct seq_file *m, void *v, loff_t *pos)
+{
+	long i = (long)m->private;
+
+	(*pos)++;
+
+	i++;
+
+	if (i >= max_stack_trace.nr_entries ||
+	    stack_dump_trace[i] == ULONG_MAX)
+		return NULL;
+
+	m->private = (void *)i;
+
+	return &m->private;
+}
+
+static void *t_start(struct seq_file *m, loff_t *pos)
+{
+	void *t = &m->private;
+	loff_t l = 0;
+
+	local_irq_disable();
+	__raw_spin_lock(&max_stack_lock);
+
+	for (; t && l < *pos; t = t_next(m, t, &l))
+		;
+
+	return t;
+}
+
+static void t_stop(struct seq_file *m, void *p)
+{
+	__raw_spin_unlock(&max_stack_lock);
+	local_irq_enable();
+}
+
+static int trace_lookup_stack(struct seq_file *m, long i)
+{
+	unsigned long addr = stack_dump_trace[i];
+#ifdef CONFIG_KALLSYMS
+	char str[KSYM_SYMBOL_LEN];
+
+	sprint_symbol(str, addr);
+
+	return seq_printf(m, "%s\n", str);
+#else
+	return seq_printf(m, "%p\n", (void*)addr);
+#endif
+}
+
+static int t_show(struct seq_file *m, void *v)
+{
+	long i = *(long *)v;
+	int size;
+
+	if (i < 0) {
+		seq_printf(m, "        Depth   Size      Location"
+			   "    (%d entries)\n"
+			   "        -----   ----      --------\n",
+			   max_stack_trace.nr_entries);
+		return 0;
+	}
+
+	if (i >= max_stack_trace.nr_entries ||
+	    stack_dump_trace[i] == ULONG_MAX)
+		return 0;
+
+	if (i+1 == max_stack_trace.nr_entries ||
+	    stack_dump_trace[i+1] == ULONG_MAX)
+		size = stack_dump_index[i];
+	else
+		size = stack_dump_index[i] - stack_dump_index[i+1];
+
+	seq_printf(m, "%3ld) %8d   %5d   ", i, stack_dump_index[i], size);
+
+	trace_lookup_stack(m, i);
+
+	return 0;
+}
+
+static struct seq_operations stack_trace_seq_ops = {
+	.start		= t_start,
+	.next		= t_next,
+	.stop		= t_stop,
+	.show		= t_show,
+};
+
+static int stack_trace_open(struct inode *inode, struct file *file)
+{
+	int ret;
+
+	ret = seq_open(file, &stack_trace_seq_ops);
+	if (!ret) {
+		struct seq_file *m = file->private_data;
+		m->private = (void *)-1;
+	}
+
+	return ret;
+}
+
+static struct file_operations stack_trace_fops = {
+	.open		= stack_trace_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+};
+
+static __init int stack_trace_init(void)
+{
+	struct dentry *d_tracer;
+	struct dentry *entry;
+
+	d_tracer = tracing_init_dentry();
+
+	entry = debugfs_create_file("stack_max_size", 0644, d_tracer,
+				    &max_stack_size, &stack_max_size_fops);
+	if (!entry)
+		pr_warning("Could not create debugfs 'stack_max_size' entry\n");
+
+	entry = debugfs_create_file("stack_trace", 0444, d_tracer,
+				    NULL, &stack_trace_fops);
+	if (!entry)
+		pr_warning("Could not create debugfs 'stack_trace' entry\n");
+
+	register_ftrace_function(&trace_ops);
+
+	return 0;
+}
+
+device_initcall(stack_trace_init);

kernel/trace/trace_sysprof.c

@@ -241,7 +241,7 @@ static void stack_reset(struct trace_array *tr)
 	tr->time_start = ftrace_now(tr->cpu);
 
 	for_each_online_cpu(cpu)
-		tracing_reset(tr->data[cpu]);
+		tracing_reset(tr, cpu);
 }
 
 static void start_stack_trace(struct trace_array *tr)

kernel/tracepoint.c

@@ -0,0 +1,477 @@
+/*
+ * Copyright (C) 2008 Mathieu Desnoyers
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ */
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/types.h>
+#include <linux/jhash.h>
+#include <linux/list.h>
+#include <linux/rcupdate.h>
+#include <linux/tracepoint.h>
+#include <linux/err.h>
+#include <linux/slab.h>
+
+extern struct tracepoint __start___tracepoints[];
+extern struct tracepoint __stop___tracepoints[];
+
+/* Set to 1 to enable tracepoint debug output */
+static const int tracepoint_debug;
+
+/*
+ * tracepoints_mutex nests inside module_mutex. Tracepoints mutex protects the
+ * builtin and module tracepoints and the hash table.
+ */
+static DEFINE_MUTEX(tracepoints_mutex);
+
+/*
+ * Tracepoint hash table, containing the active tracepoints.
+ * Protected by tracepoints_mutex.
+ */
+#define TRACEPOINT_HASH_BITS 6
+#define TRACEPOINT_TABLE_SIZE (1 << TRACEPOINT_HASH_BITS)
+
+/*
+ * Note about RCU :
+ * It is used to to delay the free of multiple probes array until a quiescent
+ * state is reached.
+ * Tracepoint entries modifications are protected by the tracepoints_mutex.
+ */
+struct tracepoint_entry {
+	struct hlist_node hlist;
+	void **funcs;
+	int refcount;	/* Number of times armed. 0 if disarmed. */
+	struct rcu_head rcu;
+	void *oldptr;
+	unsigned char rcu_pending:1;
+	char name[0];
+};
+
+static struct hlist_head tracepoint_table[TRACEPOINT_TABLE_SIZE];
+
+static void free_old_closure(struct rcu_head *head)
+{
+	struct tracepoint_entry *entry = container_of(head,
+		struct tracepoint_entry, rcu);
+	kfree(entry->oldptr);
+	/* Make sure we free the data before setting the pending flag to 0 */
+	smp_wmb();
+	entry->rcu_pending = 0;
+}
+
+static void tracepoint_entry_free_old(struct tracepoint_entry *entry, void *old)
+{
+	if (!old)
+		return;
+	entry->oldptr = old;
+	entry->rcu_pending = 1;
+	/* write rcu_pending before calling the RCU callback */
+	smp_wmb();
+	call_rcu_sched(&entry->rcu, free_old_closure);
+}
+
+static void debug_print_probes(struct tracepoint_entry *entry)
+{
+	int i;
+
+	if (!tracepoint_debug)
+		return;
+
+	for (i = 0; entry->funcs[i]; i++)
+		printk(KERN_DEBUG "Probe %d : %p\n", i, entry->funcs[i]);
+}
+
+static void *
+tracepoint_entry_add_probe(struct tracepoint_entry *entry, void *probe)
+{
+	int nr_probes = 0;
+	void **old, **new;
+
+	WARN_ON(!probe);
+
+	debug_print_probes(entry);
+	old = entry->funcs;
+	if (old) {
+		/* (N -> N+1), (N != 0, 1) probes */
+		for (nr_probes = 0; old[nr_probes]; nr_probes++)
+			if (old[nr_probes] == probe)
+				return ERR_PTR(-EEXIST);
+	}
+	/* + 2 : one for new probe, one for NULL func */
+	new = kzalloc((nr_probes + 2) * sizeof(void *), GFP_KERNEL);
+	if (new == NULL)
+		return ERR_PTR(-ENOMEM);
+	if (old)
+		memcpy(new, old, nr_probes * sizeof(void *));
+	new[nr_probes] = probe;
+	entry->refcount = nr_probes + 1;
+	entry->funcs = new;
+	debug_print_probes(entry);
+	return old;
+}
+
+static void *
+tracepoint_entry_remove_probe(struct tracepoint_entry *entry, void *probe)
+{
+	int nr_probes = 0, nr_del = 0, i;
+	void **old, **new;
+
+	old = entry->funcs;
+
+	debug_print_probes(entry);
+	/* (N -> M), (N > 1, M >= 0) probes */
+	for (nr_probes = 0; old[nr_probes]; nr_probes++) {
+		if ((!probe || old[nr_probes] == probe))
+			nr_del++;
+	}
+
+	if (nr_probes - nr_del == 0) {
+		/* N -> 0, (N > 1) */
+		entry->funcs = NULL;
+		entry->refcount = 0;
+		debug_print_probes(entry);
+		return old;
+	} else {
+		int j = 0;
+		/* N -> M, (N > 1, M > 0) */
+		/* + 1 for NULL */
+		new = kzalloc((nr_probes - nr_del + 1)
+			* sizeof(void *), GFP_KERNEL);
+		if (new == NULL)
+			return ERR_PTR(-ENOMEM);
+		for (i = 0; old[i]; i++)
+			if ((probe && old[i] != probe))
+				new[j++] = old[i];
+		entry->refcount = nr_probes - nr_del;
+		entry->funcs = new;
+	}
+	debug_print_probes(entry);
+	return old;
+}
+
+/*
+ * Get tracepoint if the tracepoint is present in the tracepoint hash table.
+ * Must be called with tracepoints_mutex held.
+ * Returns NULL if not present.
+ */
+static struct tracepoint_entry *get_tracepoint(const char *name)
+{
+	struct hlist_head *head;
+	struct hlist_node *node;
+	struct tracepoint_entry *e;
+	u32 hash = jhash(name, strlen(name), 0);
+
+	head = &tracepoint_table[hash & (TRACEPOINT_TABLE_SIZE - 1)];
+	hlist_for_each_entry(e, node, head, hlist) {
+		if (!strcmp(name, e->name))
+			return e;
+	}
+	return NULL;
+}
+
+/*
+ * Add the tracepoint to the tracepoint hash table. Must be called with
+ * tracepoints_mutex held.
+ */
+static struct tracepoint_entry *add_tracepoint(const char *name)
+{
+	struct hlist_head *head;
+	struct hlist_node *node;
+	struct tracepoint_entry *e;
+	size_t name_len = strlen(name) + 1;
+	u32 hash = jhash(name, name_len-1, 0);
+
+	head = &tracepoint_table[hash & (TRACEPOINT_TABLE_SIZE - 1)];
+	hlist_for_each_entry(e, node, head, hlist) {
+		if (!strcmp(name, e->name)) {
+			printk(KERN_NOTICE
+				"tracepoint %s busy\n", name);
+			return ERR_PTR(-EEXIST);	/* Already there */
+		}
+	}
+	/*
+	 * Using kmalloc here to allocate a variable length element. Could
+	 * cause some memory fragmentation if overused.
+	 */
+	e = kmalloc(sizeof(struct tracepoint_entry) + name_len, GFP_KERNEL);
+	if (!e)
+		return ERR_PTR(-ENOMEM);
+	memcpy(&e->name[0], name, name_len);
+	e->funcs = NULL;
+	e->refcount = 0;
+	e->rcu_pending = 0;
+	hlist_add_head(&e->hlist, head);
+	return e;
+}
+
+/*
+ * Remove the tracepoint from the tracepoint hash table. Must be called with
+ * mutex_lock held.
+ */
+static int remove_tracepoint(const char *name)
+{
+	struct hlist_head *head;
+	struct hlist_node *node;
+	struct tracepoint_entry *e;
+	int found = 0;
+	size_t len = strlen(name) + 1;
+	u32 hash = jhash(name, len-1, 0);
+
+	head = &tracepoint_table[hash & (TRACEPOINT_TABLE_SIZE - 1)];
+	hlist_for_each_entry(e, node, head, hlist) {
+		if (!strcmp(name, e->name)) {
+			found = 1;
+			break;
+		}
+	}
+	if (!found)
+		return -ENOENT;
+	if (e->refcount)
+		return -EBUSY;
+	hlist_del(&e->hlist);
+	/* Make sure the call_rcu_sched has been executed */
+	if (e->rcu_pending)
+		rcu_barrier_sched();
+	kfree(e);
+	return 0;
+}
+
+/*
+ * Sets the probe callback corresponding to one tracepoint.
+ */
+static void set_tracepoint(struct tracepoint_entry **entry,
+	struct tracepoint *elem, int active)
+{
+	WARN_ON(strcmp((*entry)->name, elem->name) != 0);
+
+	/*
+	 * rcu_assign_pointer has a smp_wmb() which makes sure that the new
+	 * probe callbacks array is consistent before setting a pointer to it.
+	 * This array is referenced by __DO_TRACE from
+	 * include/linux/tracepoints.h. A matching smp_read_barrier_depends()
+	 * is used.
+	 */
+	rcu_assign_pointer(elem->funcs, (*entry)->funcs);
+	elem->state = active;
+}
+
+/*
+ * Disable a tracepoint and its probe callback.
+ * Note: only waiting an RCU period after setting elem->call to the empty
+ * function insures that the original callback is not used anymore. This insured
+ * by preempt_disable around the call site.
+ */
+static void disable_tracepoint(struct tracepoint *elem)
+{
+	elem->state = 0;
+}
+
+/**
+ * tracepoint_update_probe_range - Update a probe range
+ * @begin: beginning of the range
+ * @end: end of the range
+ *
+ * Updates the probe callback corresponding to a range of tracepoints.
+ */
+void tracepoint_update_probe_range(struct tracepoint *begin,
+	struct tracepoint *end)
+{
+	struct tracepoint *iter;
+	struct tracepoint_entry *mark_entry;
+
+	mutex_lock(&tracepoints_mutex);
+	for (iter = begin; iter < end; iter++) {
+		mark_entry = get_tracepoint(iter->name);
+		if (mark_entry) {
+			set_tracepoint(&mark_entry, iter,
+					!!mark_entry->refcount);
+		} else {
+			disable_tracepoint(iter);
+		}
+	}
+	mutex_unlock(&tracepoints_mutex);
+}
+
+/*
+ * Update probes, removing the faulty probes.
+ */
+static void tracepoint_update_probes(void)
+{
+	/* Core kernel tracepoints */
+	tracepoint_update_probe_range(__start___tracepoints,
+		__stop___tracepoints);
+	/* tracepoints in modules. */
+	module_update_tracepoints();
+}
+
+/**
+ * tracepoint_probe_register -  Connect a probe to a tracepoint
+ * @name: tracepoint name
+ * @probe: probe handler
+ *
+ * Returns 0 if ok, error value on error.
+ * The probe address must at least be aligned on the architecture pointer size.
+ */
+int tracepoint_probe_register(const char *name, void *probe)
+{
+	struct tracepoint_entry *entry;
+	int ret = 0;
+	void *old;
+
+	mutex_lock(&tracepoints_mutex);
+	entry = get_tracepoint(name);
+	if (!entry) {
+		entry = add_tracepoint(name);
+		if (IS_ERR(entry)) {
+			ret = PTR_ERR(entry);
+			goto end;
+		}
+	}
+	/*
+	 * If we detect that a call_rcu_sched is pending for this tracepoint,
+	 * make sure it's executed now.
+	 */
+	if (entry->rcu_pending)
+		rcu_barrier_sched();
+	old = tracepoint_entry_add_probe(entry, probe);
+	if (IS_ERR(old)) {
+		ret = PTR_ERR(old);
+		goto end;
+	}
+	mutex_unlock(&tracepoints_mutex);
+	tracepoint_update_probes();		/* may update entry */
+	mutex_lock(&tracepoints_mutex);
+	entry = get_tracepoint(name);
+	WARN_ON(!entry);
+	if (entry->rcu_pending)
+		rcu_barrier_sched();
+	tracepoint_entry_free_old(entry, old);
+end:
+	mutex_unlock(&tracepoints_mutex);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(tracepoint_probe_register);
+
+/**
+ * tracepoint_probe_unregister -  Disconnect a probe from a tracepoint
+ * @name: tracepoint name
+ * @probe: probe function pointer
+ *
+ * We do not need to call a synchronize_sched to make sure the probes have
+ * finished running before doing a module unload, because the module unload
+ * itself uses stop_machine(), which insures that every preempt disabled section
+ * have finished.
+ */
+int tracepoint_probe_unregister(const char *name, void *probe)
+{
+	struct tracepoint_entry *entry;
+	void *old;
+	int ret = -ENOENT;
+
+	mutex_lock(&tracepoints_mutex);
+	entry = get_tracepoint(name);
+	if (!entry)
+		goto end;
+	if (entry->rcu_pending)
+		rcu_barrier_sched();
+	old = tracepoint_entry_remove_probe(entry, probe);
+	mutex_unlock(&tracepoints_mutex);
+	tracepoint_update_probes();		/* may update entry */
+	mutex_lock(&tracepoints_mutex);
+	entry = get_tracepoint(name);
+	if (!entry)
+		goto end;
+	if (entry->rcu_pending)
+		rcu_barrier_sched();
+	tracepoint_entry_free_old(entry, old);
+	remove_tracepoint(name);	/* Ignore busy error message */
+	ret = 0;
+end:
+	mutex_unlock(&tracepoints_mutex);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(tracepoint_probe_unregister);
+
+/**
+ * tracepoint_get_iter_range - Get a next tracepoint iterator given a range.
+ * @tracepoint: current tracepoints (in), next tracepoint (out)
+ * @begin: beginning of the range
+ * @end: end of the range
+ *
+ * Returns whether a next tracepoint has been found (1) or not (0).
+ * Will return the first tracepoint in the range if the input tracepoint is
+ * NULL.
+ */
+int tracepoint_get_iter_range(struct tracepoint **tracepoint,
+	struct tracepoint *begin, struct tracepoint *end)
+{
+	if (!*tracepoint && begin != end) {
+		*tracepoint = begin;
+		return 1;
+	}
+	if (*tracepoint >= begin && *tracepoint < end)
+		return 1;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(tracepoint_get_iter_range);
+
+static void tracepoint_get_iter(struct tracepoint_iter *iter)
+{
+	int found = 0;
+
+	/* Core kernel tracepoints */
+	if (!iter->module) {
+		found = tracepoint_get_iter_range(&iter->tracepoint,
+				__start___tracepoints, __stop___tracepoints);
+		if (found)
+			goto end;
+	}
+	/* tracepoints in modules. */
+	found = module_get_iter_tracepoints(iter);
+end:
+	if (!found)
+		tracepoint_iter_reset(iter);
+}
+
+void tracepoint_iter_start(struct tracepoint_iter *iter)
+{
+	tracepoint_get_iter(iter);
+}
+EXPORT_SYMBOL_GPL(tracepoint_iter_start);
+
+void tracepoint_iter_next(struct tracepoint_iter *iter)
+{
+	iter->tracepoint++;
+	/*
+	 * iter->tracepoint may be invalid because we blindly incremented it.
+	 * Make sure it is valid by marshalling on the tracepoints, getting the
+	 * tracepoints from following modules if necessary.
+	 */
+	tracepoint_get_iter(iter);
+}
+EXPORT_SYMBOL_GPL(tracepoint_iter_next);
+
+void tracepoint_iter_stop(struct tracepoint_iter *iter)
+{
+}
+EXPORT_SYMBOL_GPL(tracepoint_iter_stop);
+
+void tracepoint_iter_reset(struct tracepoint_iter *iter)
+{
+	iter->module = NULL;
+	iter->tracepoint = NULL;
+}
+EXPORT_SYMBOL_GPL(tracepoint_iter_reset);

samples/Kconfig

@@ -13,6 +13,12 @@ config SAMPLE_MARKERS
 	help
 	  This build markers example modules.
 
+config SAMPLE_TRACEPOINTS
+	tristate "Build tracepoints examples -- loadable modules only"
+	depends on TRACEPOINTS && m
+	help
+	  This build tracepoints example modules.
+
 config SAMPLE_KOBJECT
 	tristate "Build kobject examples"
 	help

samples/Makefile

@@ -1,3 +1,3 @@
 # Makefile for Linux samples code
 
-obj-$(CONFIG_SAMPLES)	+= markers/ kobject/ kprobes/
+obj-$(CONFIG_SAMPLES)	+= markers/ kobject/ kprobes/ tracepoints/

samples/markers/probe-example.c

@@ -81,6 +81,7 @@ static void __exit probe_fini(void)
 			probe_array[i].probe_func, &probe_array[i]);
 	printk(KERN_INFO "Number of event b : %u\n",
 			atomic_read(&eventb_count));
+	marker_synchronize_unregister();
 }
 
 module_init(probe_init);

samples/tracepoints/Makefile

@@ -0,0 +1,6 @@
+# builds the tracepoint example kernel modules;
+# then to use one (as root):  insmod <module_name.ko>
+
+obj-$(CONFIG_SAMPLE_TRACEPOINTS) += tracepoint-sample.o
+obj-$(CONFIG_SAMPLE_TRACEPOINTS) += tracepoint-probe-sample.o
+obj-$(CONFIG_SAMPLE_TRACEPOINTS) += tracepoint-probe-sample2.o

samples/tracepoints/tp-samples-trace.h

@@ -0,0 +1,13 @@
+#ifndef _TP_SAMPLES_TRACE_H
+#define _TP_SAMPLES_TRACE_H
+
+#include <linux/proc_fs.h>	/* for struct inode and struct file */
+#include <linux/tracepoint.h>
+
+DEFINE_TRACE(subsys_event,
+	TPPROTO(struct inode *inode, struct file *file),
+	TPARGS(inode, file));
+DEFINE_TRACE(subsys_eventb,
+	TPPROTO(void),
+	TPARGS());
+#endif

samples/tracepoints/tracepoint-probe-sample.c

@@ -0,0 +1,55 @@
+/*
+ * tracepoint-probe-sample.c
+ *
+ * sample tracepoint probes.
+ */
+
+#include <linux/module.h>
+#include <linux/file.h>
+#include <linux/dcache.h>
+#include "tp-samples-trace.h"
+
+/*
+ * Here the caller only guarantees locking for struct file and struct inode.
+ * Locking must therefore be done in the probe to use the dentry.
+ */
+static void probe_subsys_event(struct inode *inode, struct file *file)
+{
+	path_get(&file->f_path);
+	dget(file->f_path.dentry);
+	printk(KERN_INFO "Event is encountered with filename %s\n",
+		file->f_path.dentry->d_name.name);
+	dput(file->f_path.dentry);
+	path_put(&file->f_path);
+}
+
+static void probe_subsys_eventb(void)
+{
+	printk(KERN_INFO "Event B is encountered\n");
+}
+
+int __init tp_sample_trace_init(void)
+{
+	int ret;
+
+	ret = register_trace_subsys_event(probe_subsys_event);
+	WARN_ON(ret);
+	ret = register_trace_subsys_eventb(probe_subsys_eventb);
+	WARN_ON(ret);
+
+	return 0;
+}
+
+module_init(tp_sample_trace_init);
+
+void __exit tp_sample_trace_exit(void)
+{
+	unregister_trace_subsys_eventb(probe_subsys_eventb);
+	unregister_trace_subsys_event(probe_subsys_event);
+}
+
+module_exit(tp_sample_trace_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Mathieu Desnoyers");
+MODULE_DESCRIPTION("Tracepoint Probes Samples");

samples/tracepoints/tracepoint-probe-sample2.c

@@ -0,0 +1,42 @@
+/*
+ * tracepoint-probe-sample2.c
+ *
+ * 2nd sample tracepoint probes.
+ */
+
+#include <linux/module.h>
+#include <linux/fs.h>
+#include "tp-samples-trace.h"
+
+/*
+ * Here the caller only guarantees locking for struct file and struct inode.
+ * Locking must therefore be done in the probe to use the dentry.
+ */
+static void probe_subsys_event(struct inode *inode, struct file *file)
+{
+	printk(KERN_INFO "Event is encountered with inode number %lu\n",
+		inode->i_ino);
+}
+
+int __init tp_sample_trace_init(void)
+{
+	int ret;
+
+	ret = register_trace_subsys_event(probe_subsys_event);
+	WARN_ON(ret);
+
+	return 0;
+}
+
+module_init(tp_sample_trace_init);
+
+void __exit tp_sample_trace_exit(void)
+{
+	unregister_trace_subsys_event(probe_subsys_event);
+}
+
+module_exit(tp_sample_trace_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Mathieu Desnoyers");
+MODULE_DESCRIPTION("Tracepoint Probes Samples");

samples/tracepoints/tracepoint-sample.c

@@ -0,0 +1,53 @@
+/* tracepoint-sample.c
+ *
+ * Executes a tracepoint when /proc/tracepoint-example is opened.
+ *
+ * (C) Copyright 2007 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
+ *
+ * This file is released under the GPLv2.
+ * See the file COPYING for more details.
+ */
+
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/proc_fs.h>
+#include "tp-samples-trace.h"
+
+struct proc_dir_entry *pentry_example;
+
+static int my_open(struct inode *inode, struct file *file)
+{
+	int i;
+
+	trace_subsys_event(inode, file);
+	for (i = 0; i < 10; i++)
+		trace_subsys_eventb();
+	return -EPERM;
+}
+
+static struct file_operations mark_ops = {
+	.open = my_open,
+};
+
+static int example_init(void)
+{
+	printk(KERN_ALERT "example init\n");
+	pentry_example = proc_create("tracepoint-example", 0444, NULL,
+		&mark_ops);
+	if (!pentry_example)
+		return -EPERM;
+	return 0;
+}
+
+static void example_exit(void)
+{
+	printk(KERN_ALERT "example exit\n");
+	remove_proc_entry("tracepoint-example", NULL);
+}
+
+module_init(example_init)
+module_exit(example_exit)
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Mathieu Desnoyers");
+MODULE_DESCRIPTION("Tracepoint example");

scripts/Makefile.build

@@ -198,10 +198,17 @@ cmd_modversions =							\
 	fi;
 endif
 
+ifdef CONFIG_FTRACE_MCOUNT_RECORD
+cmd_record_mcount = perl $(srctree)/scripts/recordmcount.pl \
+	"$(ARCH)" "$(OBJDUMP)" "$(OBJCOPY)" "$(CC)" "$(LD)" "$(NM)" "$(RM)" \
+	"$(MV)" "$(@)";
+endif
+
 define rule_cc_o_c
 	$(call echo-cmd,checksrc) $(cmd_checksrc)			  \
 	$(call echo-cmd,cc_o_c) $(cmd_cc_o_c);				  \
 	$(cmd_modversions)						  \
+	$(cmd_record_mcount)						  \
 	scripts/basic/fixdep $(depfile) $@ '$(call make-cmd,cc_o_c)' >    \
 	                                              $(dot-target).tmp;  \
 	rm -f $(depfile);						  \

scripts/bootgraph.pl

@@ -37,13 +37,13 @@
 # 	dmesg | perl scripts/bootgraph.pl > output.svg
 #
 
-my @rows;
-my %start, %end, %row;
+my %start, %end;
 my $done = 0;
-my $rowcount = 0;
 my $maxtime = 0;
 my $firsttime = 100;
 my $count = 0;
+my %pids;
+
 while (<>) {
 	my $line = $_;
 	if ($line =~ /([0-9\.]+)\] calling  ([a-zA-Z0-9\_]+)\+/) {
@@ -54,14 +54,8 @@ while (<>) {
 				$firsttime = $1;
 			}
 		}
-		$row{$func} = 1;
 		if ($line =~ /\@ ([0-9]+)/) {
-			my $pid = $1;
-			if (!defined($rows[$pid])) {
-				$rowcount = $rowcount + 1;
-				$rows[$pid] = $rowcount;
-			}
-			$row{$func} = $rows[$pid];
+			$pids{$func} = $1;
 		}
 		$count = $count + 1;
 	}
@@ -109,17 +103,25 @@ $styles[11] = "fill:rgb(128,255,255);fill-opacity:0.5;stroke-width:1;stroke:rgb(
 my $mult = 950.0 / ($maxtime - $firsttime);
 my $threshold = ($maxtime - $firsttime) / 60.0;
 my $stylecounter = 0;
+my %rows;
+my $rowscount = 1;
 while (($key,$value) = each %start) {
 	my $duration = $end{$key} - $start{$key};
 
 	if ($duration >= $threshold) {
 		my $s, $s2, $e, $y;
+		$pid = $pids{$key};
+
+		if (!defined($rows{$pid})) {
+			$rows{$pid} = $rowscount;
+			$rowscount = $rowscount + 1;
+		}
 		$s = ($value - $firsttime) * $mult;
 		$s2 = $s + 6;
 		$e = ($end{$key} - $firsttime) * $mult;
 		$w = $e - $s;
 
-		$y = $row{$key} * 150;
+		$y = $rows{$pid} * 150;
 		$y2 = $y + 4;
 
 		$style = $styles[$stylecounter];

scripts/recordmcount.pl

@@ -0,0 +1,395 @@
+#!/usr/bin/perl -w
+# (c) 2008, Steven Rostedt <srostedt@redhat.com>
+# Licensed under the terms of the GNU GPL License version 2
+#
+# recordmcount.pl - makes a section called __mcount_loc that holds
+#                   all the offsets to the calls to mcount.
+#
+#
+# What we want to end up with is a section in vmlinux called
+# __mcount_loc that contains a list of pointers to all the
+# call sites in the kernel that call mcount. Later on boot up, the kernel
+# will read this list, save the locations and turn them into nops.
+# When tracing or profiling is later enabled, these locations will then
+# be converted back to pointers to some function.
+#
+# This is no easy feat. This script is called just after the original
+# object is compiled and before it is linked.
+#
+# The references to the call sites are offsets from the section of text
+# that the call site is in. Hence, all functions in a section that
+# has a call site to mcount, will have the offset from the beginning of
+# the section and not the beginning of the function.
+#
+# The trick is to find a way to record the beginning of the section.
+# The way we do this is to look at the first function in the section
+# which will also be the location of that section after final link.
+# e.g.
+#
+#  .section ".text.sched"
+#  .globl my_func
+#  my_func:
+#        [...]
+#        call mcount  (offset: 0x5)
+#        [...]
+#        ret
+#  other_func:
+#        [...]
+#        call mcount (offset: 0x1b)
+#        [...]
+#
+# Both relocation offsets for the mcounts in the above example will be
+# offset from .text.sched. If we make another file called tmp.s with:
+#
+#  .section __mcount_loc
+#  .quad  my_func + 0x5
+#  .quad  my_func + 0x1b
+#
+# We can then compile this tmp.s into tmp.o, and link it to the original
+# object.
+#
+# But this gets hard if my_func is not globl (a static function).
+# In such a case we have:
+#
+#  .section ".text.sched"
+#  my_func:
+#        [...]
+#        call mcount  (offset: 0x5)
+#        [...]
+#        ret
+#  .globl my_func
+#  other_func:
+#        [...]
+#        call mcount (offset: 0x1b)
+#        [...]
+#
+# If we make the tmp.s the same as above, when we link together with
+# the original object, we will end up with two symbols for my_func:
+# one local, one global.  After final compile, we will end up with
+# an undefined reference to my_func.
+#
+# Since local objects can reference local variables, we need to find
+# a way to make tmp.o reference the local objects of the original object
+# file after it is linked together. To do this, we convert the my_func
+# into a global symbol before linking tmp.o. Then after we link tmp.o
+# we will only have a single symbol for my_func that is global.
+# We can convert my_func back into a local symbol and we are done.
+#
+# Here are the steps we take:
+#
+# 1) Record all the local symbols by using 'nm'
+# 2) Use objdump to find all the call site offsets and sections for
+#    mcount.
+# 3) Compile the list into its own object.
+# 4) Do we have to deal with local functions? If not, go to step 8.
+# 5) Make an object that converts these local functions to global symbols
+#    with objcopy.
+# 6) Link together this new object with the list object.
+# 7) Convert the local functions back to local symbols and rename
+#    the result as the original object.
+#    End.
+# 8) Link the object with the list object.
+# 9) Move the result back to the original object.
+#    End.
+#
+
+use strict;
+
+my $P = $0;
+$P =~ s@.*/@@g;
+
+my $V = '0.1';
+
+if ($#ARGV < 6) {
+	print "usage: $P arch objdump objcopy cc ld nm rm mv inputfile\n";
+	print "version: $V\n";
+	exit(1);
+}
+
+my ($arch, $objdump, $objcopy, $cc, $ld, $nm, $rm, $mv, $inputfile) = @ARGV;
+
+$objdump = "objdump" if ((length $objdump) == 0);
+$objcopy = "objcopy" if ((length $objcopy) == 0);
+$cc = "gcc" if ((length $cc) == 0);
+$ld = "ld" if ((length $ld) == 0);
+$nm = "nm" if ((length $nm) == 0);
+$rm = "rm" if ((length $rm) == 0);
+$mv = "mv" if ((length $mv) == 0);
+
+#print STDERR "running: $P '$arch' '$objdump' '$objcopy' '$cc' '$ld' " .
+#    "'$nm' '$rm' '$mv' '$inputfile'\n";
+
+my %locals;		# List of local (static) functions
+my %weak;		# List of weak functions
+my %convert;		# List of local functions used that needs conversion
+
+my $type;
+my $section_regex;	# Find the start of a section
+my $function_regex;	# Find the name of a function
+			#    (return offset and func name)
+my $mcount_regex;	# Find the call site to mcount (return offset)
+
+if ($arch eq "x86_64") {
+    $section_regex = "Disassembly of section";
+    $function_regex = "^([0-9a-fA-F]+)\\s+<(.*?)>:";
+    $mcount_regex = "^\\s*([0-9a-fA-F]+):.*\\smcount([+-]0x[0-9a-zA-Z]+)?\$";
+    $type = ".quad";
+
+    # force flags for this arch
+    $ld .= " -m elf_x86_64";
+    $objdump .= " -M x86-64";
+    $objcopy .= " -O elf64-x86-64";
+    $cc .= " -m64";
+
+} elsif ($arch eq "i386") {
+    $section_regex = "Disassembly of section";
+    $function_regex = "^([0-9a-fA-F]+)\\s+<(.*?)>:";
+    $mcount_regex = "^\\s*([0-9a-fA-F]+):.*\\smcount\$";
+    $type = ".long";
+
+    # force flags for this arch
+    $ld .= " -m elf_i386";
+    $objdump .= " -M i386";
+    $objcopy .= " -O elf32-i386";
+    $cc .= " -m32";
+
+} else {
+    die "Arch $arch is not supported with CONFIG_FTRACE_MCOUNT_RECORD";
+}
+
+my $text_found = 0;
+my $read_function = 0;
+my $opened = 0;
+my $mcount_section = "__mcount_loc";
+
+my $dirname;
+my $filename;
+my $prefix;
+my $ext;
+
+if ($inputfile =~ m,^(.*)/([^/]*)$,) {
+    $dirname = $1;
+    $filename = $2;
+} else {
+    $dirname = ".";
+    $filename = $inputfile;
+}
+
+if ($filename =~ m,^(.*)(\.\S),) {
+    $prefix = $1;
+    $ext = $2;
+} else {
+    $prefix = $filename;
+    $ext = "";
+}
+
+my $mcount_s = $dirname . "/.tmp_mc_" . $prefix . ".s";
+my $mcount_o = $dirname . "/.tmp_mc_" . $prefix . ".o";
+
+#
+# --globalize-symbols came out in 2.17, we must test the version
+# of objcopy, and if it is less than 2.17, then we can not
+# record local functions.
+my $use_locals = 01;
+my $local_warn_once = 0;
+my $found_version = 0;
+
+open (IN, "$objcopy --version |") || die "error running $objcopy";
+while (<IN>) {
+    if (/objcopy.*\s(\d+)\.(\d+)/) {
+	my $major = $1;
+	my $minor = $2;
+
+	$found_version = 1;
+	if ($major < 2 ||
+	    ($major == 2 && $minor < 17)) {
+	    $use_locals = 0;
+	}
+	last;
+    }
+}
+close (IN);
+
+if (!$found_version) {
+    print STDERR "WARNING: could not find objcopy version.\n" .
+	"\tDisabling local function references.\n";
+}
+
+
+#
+# Step 1: find all the local (static functions) and weak symbols.
+#        't' is local, 'w/W' is weak (we never use a weak function)
+#
+open (IN, "$nm $inputfile|") || die "error running $nm";
+while (<IN>) {
+    if (/^[0-9a-fA-F]+\s+t\s+(\S+)/) {
+	$locals{$1} = 1;
+    } elsif (/^[0-9a-fA-F]+\s+([wW])\s+(\S+)/) {
+	$weak{$2} = $1;
+    }
+}
+close(IN);
+
+my @offsets;		# Array of offsets of mcount callers
+my $ref_func;		# reference function to use for offsets
+my $offset = 0;		# offset of ref_func to section beginning
+
+##
+# update_funcs - print out the current mcount callers
+#
+#  Go through the list of offsets to callers and write them to
+#  the output file in a format that can be read by an assembler.
+#
+sub update_funcs
+{
+    return if ($#offsets < 0);
+
+    defined($ref_func) || die "No function to reference";
+
+    # A section only had a weak function, to represent it.
+    # Unfortunately, a weak function may be overwritten by another
+    # function of the same name, making all these offsets incorrect.
+    # To be safe, we simply print a warning and bail.
+    if (defined $weak{$ref_func}) {
+	print STDERR
+	    "$inputfile: WARNING: referencing weak function" .
+	    " $ref_func for mcount\n";
+	return;
+    }
+
+    # is this function static? If so, note this fact.
+    if (defined $locals{$ref_func}) {
+
+	# only use locals if objcopy supports globalize-symbols
+	if (!$use_locals) {
+	    return;
+	}
+	$convert{$ref_func} = 1;
+    }
+
+    # Loop through all the mcount caller offsets and print a reference
+    # to the caller based from the ref_func.
+    for (my $i=0; $i <= $#offsets; $i++) {
+	if (!$opened) {
+	    open(FILE, ">$mcount_s") || die "can't create $mcount_s\n";
+	    $opened = 1;
+	    print FILE "\t.section $mcount_section,\"a\",\@progbits\n";
+	}
+	printf FILE "\t%s %s + %d\n", $type, $ref_func, $offsets[$i] - $offset;
+    }
+}
+
+#
+# Step 2: find the sections and mcount call sites
+#
+open(IN, "$objdump -dr $inputfile|") || die "error running $objdump";
+
+my $text;
+
+while (<IN>) {
+    # is it a section?
+    if (/$section_regex/) {
+	$read_function = 1;
+	# print out any recorded offsets
+	update_funcs() if ($text_found);
+
+	# reset all markers and arrays
+	$text_found = 0;
+	undef($ref_func);
+	undef(@offsets);
+
+    # section found, now is this a start of a function?
+    } elsif ($read_function && /$function_regex/) {
+	$text_found = 1;
+	$offset = hex $1;
+	$text = $2;
+
+	# if this is either a local function or a weak function
+	# keep looking for functions that are global that
+	# we can use safely.
+	if (!defined($locals{$text}) && !defined($weak{$text})) {
+	    $ref_func = $text;
+	    $read_function = 0;
+	} else {
+	    # if we already have a function, and this is weak, skip it
+	    if (!defined($ref_func) || !defined($weak{$text})) {
+		$ref_func = $text;
+	    }
+	}
+    }
+
+    # is this a call site to mcount? If so, record it to print later
+    if ($text_found && /$mcount_regex/) {
+	$offsets[$#offsets + 1] = hex $1;
+    }
+}
+
+# dump out anymore offsets that may have been found
+update_funcs() if ($text_found);
+
+# If we did not find any mcount callers, we are done (do nothing).
+if (!$opened) {
+    exit(0);
+}
+
+close(FILE);
+
+#
+# Step 3: Compile the file that holds the list of call sites to mcount.
+#
+`$cc -o $mcount_o -c $mcount_s`;
+
+my @converts = keys %convert;
+
+#
+# Step 4: Do we have sections that started with local functions?
+#
+if ($#converts >= 0) {
+    my $globallist = "";
+    my $locallist = "";
+
+    foreach my $con (@converts) {
+	$globallist .= " --globalize-symbol $con";
+	$locallist .= " --localize-symbol $con";
+    }
+
+    my $globalobj = $dirname . "/.tmp_gl_" . $filename;
+    my $globalmix = $dirname . "/.tmp_mx_" . $filename;
+
+    #
+    # Step 5: set up each local function as a global
+    #
+    `$objcopy $globallist $inputfile $globalobj`;
+
+    #
+    # Step 6: Link the global version to our list.
+    #
+    `$ld -r $globalobj $mcount_o -o $globalmix`;
+
+    #
+    # Step 7: Convert the local functions back into local symbols
+    #
+    `$objcopy $locallist $globalmix $inputfile`;
+
+    # Remove the temp files
+    `$rm $globalobj $globalmix`;
+
+} else {
+
+    my $mix = $dirname . "/.tmp_mx_" . $filename;
+
+    #
+    # Step 8: Link the object with our list of call sites object.
+    #
+    `$ld -r $inputfile $mcount_o -o $mix`;
+
+    #
+    # Step 9: Move the result back to the original object.
+    #
+    `$mv $mix $inputfile`;
+}
+
+# Clean up the temp files
+`$rm $mcount_o $mcount_s`;
+
+exit(0);