ftrace: extend sysprof plugin some more

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

kernel/trace/trace_sysprof.c

@@ -3,7 +3,7 @@
  *
  * Copyright (C) 2007 Steven Rostedt <srostedt@redhat.com>
  * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
- *
+ * Copyright (C) 2004, 2005, Soeren Sandmann
  */
 #include <linux/kallsyms.h>
 #include <linux/debugfs.h>
@@ -11,13 +11,17 @@
 #include <linux/uaccess.h>
 #include <linux/ftrace.h>
 #include <linux/module.h>
+#include <linux/irq.h>
 #include <linux/fs.h>
 
 #include "trace.h"
 
-static struct trace_array	*ctx_trace;
+static struct trace_array	*sysprof_trace;
 static int __read_mostly	tracer_enabled;
 
+/*
+ * 10 msecs for now:
+ */
 static const unsigned long sample_period = 1000000;
 
 /*
@@ -25,10 +29,78 @@ static const unsigned long sample_period = 1000000;
  */
 static DEFINE_PER_CPU(struct hrtimer, stack_trace_hrtimer);
 
+struct stack_frame {
+	const void __user	*next_fp;
+	unsigned long		return_address;
+};
+
+static int copy_stack_frame(const void __user *fp, struct stack_frame *frame)
+{
+	if (!access_ok(VERIFY_READ, fp, sizeof(*frame)))
+		return 0;
+
+	if (__copy_from_user_inatomic(frame, frame_pointer, sizeof(*frame)))
+		return 0;
+
+	return 1;
+}
+
+#define SYSPROF_MAX_ADDRESSES	512
+
+static void timer_notify(struct pt_regs *regs, int cpu)
+{
+	const void __user *frame_pointer;
+	struct trace_array_cpu *data;
+	struct stack_frame frame;
+	struct trace_array *tr;
+	int is_user;
+	int i;
+
+	if (!regs)
+		return;
+
+	tr = sysprof_trace;
+	data = tr->data[cpu];
+	is_user = user_mode(regs);
+
+	if (!current || current->pid == 0)
+		return;
+
+	if (is_user && current->state != TASK_RUNNING)
+		return;
+
+	if (!is_user) {
+		/* kernel */
+		ftrace(tr, data, current->pid, 1, 0);
+		return;
+
+	}
+
+	trace_special(tr, data, 0, current->pid, regs->ip);
+
+	frame_pointer = (void __user *)regs->bp;
+
+	for (i = 0; i < SYSPROF_MAX_ADDRESSES; i++) {
+		if (!copy_stack_frame(frame_pointer, &frame))
+			break;
+		if ((unsigned long)frame_pointer < regs->sp)
+			break;
+
+		trace_special(tr, data, 1, frame.return_address,
+			      (unsigned long)frame_pointer);
+		frame_pointer = frame.next_fp;
+	}
+
+	trace_special(tr, data, 2, current->pid, i);
+
+	if (i == SYSPROF_MAX_ADDRESSES)
+		trace_special(tr, data, -1, -1, -1);
+}
+
 static enum hrtimer_restart stack_trace_timer_fn(struct hrtimer *hrtimer)
 {
 	/* trace here */
-	panic_timeout++;
+	timer_notify(get_irq_regs(), smp_processor_id());
 
 	hrtimer_forward_now(hrtimer, ns_to_ktime(sample_period));
 
@@ -100,7 +172,7 @@ static notrace void stop_stack_trace(struct trace_array *tr)
 
 static notrace void stack_trace_init(struct trace_array *tr)
 {
-	ctx_trace = tr;
+	sysprof_trace = tr;
 
 	if (tr->ctrl)
 		start_stack_trace(tr);