x86: kprobes code for x86 unification

This patch unifies kprobes code.

- Unify kprobes_*.h to kprobes.h
- Unify kprobes_*.c to kprobes.c
  (Differences are separated by ifdefs)
 - Most differences are related to REX prefix and rip relatives.
 - Two inline assembly code are different.
 - One difference in kprobe_handlre()
 - One fixup exception code is different, but it will be unified
   if mm/extable_*.c are unified.
- Merge history logs into arch/x86/kernel/kprobes.c.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Signed-off-by: Jim Keniston <jkenisto@us.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

arch/x86/kernel/Makefile_32

@@ -35,7 +35,7 @@ obj-$(CONFIG_KEXEC)		+= machine_kexec_32.o relocate_kernel_32.o crash.o
 obj-$(CONFIG_CRASH_DUMP)	+= crash_dump_32.o
 obj-$(CONFIG_X86_NUMAQ)		+= numaq_32.o
 obj-$(CONFIG_X86_SUMMIT_NUMA)	+= summit_32.o
-obj-$(CONFIG_KPROBES)		+= kprobes_32.o
+obj-$(CONFIG_KPROBES)		+= kprobes.o
 obj-$(CONFIG_MODULES)		+= module_32.o
 obj-$(CONFIG_ACPI_SRAT) 	+= srat_32.o
 obj-$(CONFIG_EFI) 		+= efi.o efi_32.o efi_stub_32.o

arch/x86/kernel/Makefile_64

@@ -34,7 +34,7 @@ obj-$(CONFIG_EARLY_PRINTK)	+= early_printk.o
 obj-$(CONFIG_GART_IOMMU)	+= pci-gart_64.o aperture_64.o
 obj-$(CONFIG_CALGARY_IOMMU)	+= pci-calgary_64.o tce_64.o
 obj-$(CONFIG_SWIOTLB)		+= pci-swiotlb_64.o
-obj-$(CONFIG_KPROBES)		+= kprobes_64.o
+obj-$(CONFIG_KPROBES)		+= kprobes.o
 obj-$(CONFIG_X86_PM_TIMER)	+= pmtimer_64.o
 obj-$(CONFIG_X86_VSMP)		+= vsmp_64.o
 obj-$(CONFIG_K8_NB)		+= k8.o

arch/x86/kernel/kprobes_64.c → arch/x86/kernel/kprobes.c

@@ -22,14 +22,22 @@
  *		Rusty Russell).
  * 2004-July	Suparna Bhattacharya <suparna@in.ibm.com> added jumper probes
  *		interface to access function arguments.
- * 2004-Oct	Jim Keniston <kenistoj@us.ibm.com> and Prasanna S Panchamukhi
- *		<prasanna@in.ibm.com> adapted for x86_64
+ * 2004-Oct	Jim Keniston <jkenisto@us.ibm.com> and Prasanna S Panchamukhi
+ *		<prasanna@in.ibm.com> adapted for x86_64 from i386.
  * 2005-Mar	Roland McGrath <roland@redhat.com>
  *		Fixed to handle %rip-relative addressing mode correctly.
- * 2005-May     Rusty Lynch <rusty.lynch@intel.com>
- *              Added function return probes functionality
+ * 2005-May	Hien Nguyen <hien@us.ibm.com>, Jim Keniston
+ *		<jkenisto@us.ibm.com> and Prasanna S Panchamukhi
+ *		<prasanna@in.ibm.com> added function-return probes.
+ * 2005-May	Rusty Lynch <rusty.lynch@intel.com>
+ * 		Added function return probes functionality
+ * 2006-Feb	Masami Hiramatsu <hiramatu@sdl.hitachi.co.jp> added
+ * 		kprobe-booster and kretprobe-booster for i386.
  * 2007-Dec	Masami Hiramatsu <mhiramat@redhat.com> added kprobe-booster
  * 		and kretprobe-booster for x86-64
+ * 2007-Dec	Masami Hiramatsu <mhiramat@redhat.com>, Arjan van de Ven
+ * 		<arjan@infradead.org> and Jim Keniston <jkenisto@us.ibm.com>
+ * 		unified x86 kprobes code.
  */
 
 #include <linux/kprobes.h>
@@ -51,7 +59,19 @@ void jprobe_return_end(void);
 DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
 DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
 
+#ifdef CONFIG_X86_64
 #define stack_addr(regs) ((unsigned long *)regs->sp)
+#else
+/*
+ * "&regs->sp" looks wrong, but it's correct for x86_32.  x86_32 CPUs
+ * don't save the ss and esp registers if the CPU is already in kernel
+ * mode when it traps.  So for kprobes, regs->sp and regs->ss are not
+ * the [nonexistent] saved stack pointer and ss register, but rather
+ * the top 8 bytes of the pre-int3 stack.  So &regs->sp happens to
+ * point to the top of the pre-int3 stack.
+ */
+#define stack_addr(regs) ((unsigned long *)&regs->sp)
+#endif
 
 #define W(row, b0, b1, b2, b3, b4, b5, b6, b7, b8, b9, ba, bb, bc, bd, be, bf)\
 	(((b0##UL << 0x0)|(b1##UL << 0x1)|(b2##UL << 0x2)|(b3##UL << 0x3) |   \
@@ -151,8 +171,8 @@ static __always_inline void set_jmp_op(void *from, void *to)
 }
 
 /*
- * returns non-zero if opcode is boostable.
- * RIP relative instructions are adjusted at copying time
+ * Returns non-zero if opcode is boostable.
+ * RIP relative instructions are adjusted at copying time in 64 bits mode
  */
 static __always_inline int can_boost(kprobe_opcode_t *opcodes)
 {
@@ -173,8 +193,10 @@ retry:
 	}
 
 	switch (opcode & 0xf0) {
+#ifdef CONFIG_X86_64
 	case 0x40:
 		goto retry; /* REX prefix is boostable */
+#endif
 	case 0x60:
 		if (0x63 < opcode && opcode < 0x67)
 			goto retry; /* prefixes */
@@ -206,7 +228,7 @@ retry:
 }
 
 /*
- * returns non-zero if opcode modifies the interrupt flag.
+ * Returns non-zero if opcode modifies the interrupt flag.
  */
 static int __kprobes is_IF_modifier(kprobe_opcode_t *insn)
 {
@@ -217,16 +239,18 @@ static int __kprobes is_IF_modifier(kprobe_opcode_t *insn)
 	case 0x9d:		/* popf/popfd */
 		return 1;
 	}
-
+#ifdef CONFIG_X86_64
 	/*
 	 * on 64 bit x86, 0x40-0x4f are prefixes so we need to look
 	 * at the next byte instead.. but of course not recurse infinitely
 	 */
 	if (*insn  >= 0x40 && *insn <= 0x4f)
 		return is_IF_modifier(++insn);
+#endif
 	return 0;
 }
 
+#ifdef CONFIG_X86_64
 /*
  * Adjust the displacement if the instruction uses the %rip-relative
  * addressing mode.
@@ -263,17 +287,20 @@ static void __kprobes fix_riprel(struct kprobe *p)
 	if ((*insn & 0xf0) == 0x40)
 		++insn;
 
-	if (*insn == 0x0f) {	/* Two-byte opcode.  */
+	if (*insn == 0x0f) {
+		/* Two-byte opcode.  */
 		++insn;
 		need_modrm = test_bit(*insn,
 				      (unsigned long *)twobyte_has_modrm);
-	} else			/* One-byte opcode.  */
+	} else
+		/* One-byte opcode.  */
 		need_modrm = test_bit(*insn,
 				      (unsigned long *)onebyte_has_modrm);
 
 	if (need_modrm) {
 		u8 modrm = *++insn;
-		if ((modrm & 0xc7) == 0x05) { /* %rip+disp32 addressing mode */
+		if ((modrm & 0xc7) == 0x05) {
+			/* %rip+disp32 addressing mode */
 			/* Displacement follows ModRM byte.  */
 			++insn;
 			/*
@@ -296,11 +323,14 @@ static void __kprobes fix_riprel(struct kprobe *p)
 		}
 	}
 }
+#endif
 
 static void __kprobes arch_copy_kprobe(struct kprobe *p)
 {
 	memcpy(p->ainsn.insn, p->addr, MAX_INSN_SIZE * sizeof(kprobe_opcode_t));
+#ifdef CONFIG_X86_64
 	fix_riprel(p);
+#endif
 	if (can_boost(p->addr))
 		p->ainsn.boostable = 0;
 	else
@@ -365,13 +395,13 @@ static void __kprobes set_current_kprobe(struct kprobe *p, struct pt_regs *regs,
 static __always_inline void clear_btf(void)
 {
 	if (test_thread_flag(TIF_DEBUGCTLMSR))
-		wrmsrl(MSR_IA32_DEBUGCTLMSR, 0);
+		wrmsr(MSR_IA32_DEBUGCTLMSR, 0, 0);
 }
 
 static __always_inline void restore_btf(void)
 {
 	if (test_thread_flag(TIF_DEBUGCTLMSR))
-		wrmsrl(MSR_IA32_DEBUGCTLMSR, current->thread.debugctlmsr);
+		wrmsr(MSR_IA32_DEBUGCTLMSR, current->thread.debugctlmsr, 0);
 }
 
 static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs)
@@ -427,6 +457,7 @@ static int __kprobes kprobe_handler(struct pt_regs *regs)
 				regs->flags &= ~TF_MASK;
 				regs->flags |= kcb->kprobe_saved_flags;
 				goto no_kprobe;
+#ifdef CONFIG_X86_64
 			} else if (kcb->kprobe_status == KPROBE_HIT_SSDONE) {
 				/* TODO: Provide re-entrancy from
 				 * post_kprobes_handler() and avoid exception
@@ -437,6 +468,7 @@ static int __kprobes kprobe_handler(struct pt_regs *regs)
 				regs->ip = (unsigned long)p->addr;
 				reset_current_kprobe();
 				return 1;
+#endif
 			}
 			/* We have reentered the kprobe_handler(), since
 			 * another probe was hit while within the handler.
@@ -461,9 +493,8 @@ static int __kprobes kprobe_handler(struct pt_regs *regs)
 				goto no_kprobe;
 			}
 			p = __get_cpu_var(current_kprobe);
-			if (p->break_handler && p->break_handler(p, regs)) {
+			if (p->break_handler && p->break_handler(p, regs))
 				goto ss_probe;
-			}
 		}
 		goto no_kprobe;
 	}
@@ -519,8 +550,10 @@ no_kprobe:
  */
  void __kprobes kretprobe_trampoline_holder(void)
  {
- 	asm volatile (  ".global kretprobe_trampoline\n"
+	asm volatile (
+			".global kretprobe_trampoline\n"
 			"kretprobe_trampoline: \n"
+#ifdef CONFIG_X86_64
 			/* We don't bother saving the ss register */
 			"	pushq %rsp\n"
 			"	pushfq\n"
@@ -566,25 +599,64 @@ no_kprobe:
 			/* Skip orig_ax, ip, cs */
 			"	addq $24, %rsp\n"
 			"	popfq\n"
+#else
+			"	pushf\n"
+			/*
+			 * Skip cs, ip, orig_ax.
+			 * trampoline_handler() will plug in these values
+			 */
+			"	subl $12, %esp\n"
+			"	pushl %fs\n"
+			"	pushl %ds\n"
+			"	pushl %es\n"
+			"	pushl %eax\n"
+			"	pushl %ebp\n"
+			"	pushl %edi\n"
+			"	pushl %esi\n"
+			"	pushl %edx\n"
+			"	pushl %ecx\n"
+			"	pushl %ebx\n"
+			"	movl %esp, %eax\n"
+			"	call trampoline_handler\n"
+			/* Move flags to cs */
+			"	movl 52(%esp), %edx\n"
+			"	movl %edx, 48(%esp)\n"
+			/* Replace saved flags with true return address. */
+			"	movl %eax, 52(%esp)\n"
+			"	popl %ebx\n"
+			"	popl %ecx\n"
+			"	popl %edx\n"
+			"	popl %esi\n"
+			"	popl %edi\n"
+			"	popl %ebp\n"
+			"	popl %eax\n"
+			/* Skip ip, orig_ax, es, ds, fs */
+			"	addl $20, %esp\n"
+			"	popf\n"
+#endif
 			"	ret\n");
  }
 
 /*
  * Called from kretprobe_trampoline
  */
-fastcall void * __kprobes trampoline_handler(struct pt_regs *regs)
+void * __kprobes trampoline_handler(struct pt_regs *regs)
 {
 	struct kretprobe_instance *ri = NULL;
 	struct hlist_head *head, empty_rp;
 	struct hlist_node *node, *tmp;
 	unsigned long flags, orig_ret_address = 0;
-	unsigned long trampoline_address =(unsigned long)&kretprobe_trampoline;
+	unsigned long trampoline_address = (unsigned long)&kretprobe_trampoline;
 
 	INIT_HLIST_HEAD(&empty_rp);
 	spin_lock_irqsave(&kretprobe_lock, flags);
 	head = kretprobe_inst_table_head(current);
 	/* fixup registers */
+#ifdef CONFIG_X86_64
 	regs->cs = __KERNEL_CS;
+#else
+	regs->cs = __KERNEL_CS | get_kernel_rpl();
+#endif
 	regs->ip = trampoline_address;
 	regs->orig_ax = ~0UL;
 
@@ -671,9 +743,11 @@ static void __kprobes resume_execution(struct kprobe *p,
 	unsigned long orig_ip = (unsigned long)p->addr;
 	kprobe_opcode_t *insn = p->ainsn.insn;
 
+#ifdef CONFIG_X86_64
 	/*skip the REX prefix*/
 	if (*insn >= 0x40 && *insn <= 0x4f)
 		insn++;
+#endif
 
 	regs->flags &= ~TF_MASK;
 	switch (*insn) {
@@ -693,6 +767,11 @@ static void __kprobes resume_execution(struct kprobe *p,
 	case 0xe8:	/* call relative - Fix return addr */
 		*tos = orig_ip + (*tos - copy_ip);
 		break;
+#ifndef CONFIG_X86_64
+	case 0x9a:	/* call absolute -- same as call absolute, indirect */
+		*tos = orig_ip + (*tos - copy_ip);
+		goto no_change;
+#endif
 	case 0xff:
 		if ((insn[1] & 0x30) == 0x10) {
 			/*
@@ -783,9 +862,8 @@ int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
 {
 	struct kprobe *cur = kprobe_running();
 	struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
-	const struct exception_table_entry *fixup;
 
-	switch(kcb->kprobe_status) {
+	switch (kcb->kprobe_status) {
 	case KPROBE_HIT_SS:
 	case KPROBE_REENTER:
 		/*
@@ -826,12 +904,19 @@ int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
 		 * In case the user-specified fault handler returned
 		 * zero, try to fix up.
 		 */
-		fixup = search_exception_tables(regs->ip);
-		if (fixup) {
-			regs->ip = fixup->fixup;
-			return 1;
+#ifdef CONFIG_X86_64
+		{
+			const struct exception_table_entry *fixup;
+			fixup = search_exception_tables(regs->ip);
+			if (fixup) {
+				regs->ip = fixup->fixup;
+				return 1;
+			}
 		}
-
+#else
+		if (fixup_exception(regs))
+			return 1;
+#endif
 		/*
 		 * fixup routine could not handle it,
 		 * Let do_page_fault() fix it.
@@ -896,7 +981,7 @@ int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
 	 * the argument area.
 	 */
 	memcpy(kcb->jprobes_stack, (kprobe_opcode_t *)addr,
-			MIN_STACK_SIZE(addr));
+	       MIN_STACK_SIZE(addr));
 	regs->flags &= ~IF_MASK;
 	trace_hardirqs_off();
 	regs->ip = (unsigned long)(jp->entry);
@@ -907,12 +992,17 @@ void __kprobes jprobe_return(void)
 {
 	struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
 
-	asm volatile ("       xchg   %%rbx,%%rsp     \n"
-		      "       int3			\n"
-		      "       .globl jprobe_return_end	\n"
-		      "       jprobe_return_end:	\n"
-		      "       nop			\n"::"b"
-		      (kcb->jprobe_saved_sp):"memory");
+	asm volatile (
+#ifdef CONFIG_X86_64
+			"       xchg   %%rbx,%%rsp	\n"
+#else
+			"       xchgl   %%ebx,%%esp	\n"
+#endif
+			"       int3			\n"
+			"       .globl jprobe_return_end\n"
+			"       jprobe_return_end:	\n"
+			"       nop			\n"::"b"
+			(kcb->jprobe_saved_sp):"memory");
 }
 
 int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
@@ -921,14 +1011,16 @@ int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
 	u8 *addr = (u8 *) (regs->ip - 1);
 	struct jprobe *jp = container_of(p, struct jprobe, kp);
 
-	if ((addr > (u8 *) jprobe_return) && (addr < (u8 *) jprobe_return_end)) {
+	if ((addr > (u8 *) jprobe_return) &&
+	    (addr < (u8 *) jprobe_return_end)) {
 		if (stack_addr(regs) != kcb->jprobe_saved_sp) {
 			struct pt_regs *saved_regs = &kcb->jprobe_saved_regs;
-			printk("current sp %p does not match saved sp %p\n",
+			printk(KERN_ERR
+			       "current sp %p does not match saved sp %p\n",
 			       stack_addr(regs), kcb->jprobe_saved_sp);
-			printk("Saved registers for jprobe %p\n", jp);
+			printk(KERN_ERR "Saved registers for jprobe %p\n", jp);
 			show_registers(saved_regs);
-			printk("Current registers\n");
+			printk(KERN_ERR "Current registers\n");
 			show_registers(regs);
 			BUG();
 		}

arch/x86/kernel/kprobes_32.c

@@ -1,848 +0,0 @@
-/*
- *  Kernel Probes (KProbes)
- *
- * 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.
- *
- * Copyright (C) IBM Corporation, 2002, 2004
- *
- * 2002-Oct	Created by Vamsi Krishna S <vamsi_krishna@in.ibm.com> Kernel
- *		Probes initial implementation ( includes contributions from
- *		Rusty Russell).
- * 2004-July	Suparna Bhattacharya <suparna@in.ibm.com> added jumper probes
- *		interface to access function arguments.
- * 2005-May	Hien Nguyen <hien@us.ibm.com>, Jim Keniston
- *		<jkenisto@us.ibm.com> and Prasanna S Panchamukhi
- *		<prasanna@in.ibm.com> added function-return probes.
- */
-
-#include <linux/kprobes.h>
-#include <linux/ptrace.h>
-#include <linux/string.h>
-#include <linux/slab.h>
-#include <linux/preempt.h>
-#include <linux/module.h>
-#include <linux/kdebug.h>
-
-#include <asm/cacheflush.h>
-#include <asm/desc.h>
-#include <asm/pgtable.h>
-#include <asm/uaccess.h>
-#include <asm/alternative.h>
-
-void jprobe_return_end(void);
-
-DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
-DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
-
-/*
- * "&regs->sp" looks wrong, but it's correct for x86_32.  x86_32 CPUs
- * don't save the ss and esp registers if the CPU is already in kernel
- * mode when it traps.  So for kprobes, regs->sp and regs->ss are not
- * the [nonexistent] saved stack pointer and ss register, but rather
- * the top 8 bytes of the pre-int3 stack.  So &regs->sp happens to
- * point to the top of the pre-int3 stack.
- */
-#define stack_addr(regs) ((unsigned long *)&regs->sp)
-
-#define W(row, b0, b1, b2, b3, b4, b5, b6, b7, b8, b9, ba, bb, bc, bd, be, bf)\
-	(((b0##UL << 0x0)|(b1##UL << 0x1)|(b2##UL << 0x2)|(b3##UL << 0x3) |   \
-	  (b4##UL << 0x4)|(b5##UL << 0x5)|(b6##UL << 0x6)|(b7##UL << 0x7) |   \
-	  (b8##UL << 0x8)|(b9##UL << 0x9)|(ba##UL << 0xa)|(bb##UL << 0xb) |   \
-	  (bc##UL << 0xc)|(bd##UL << 0xd)|(be##UL << 0xe)|(bf##UL << 0xf))    \
-	 << (row % 32))
-	/*
-	 * Undefined/reserved opcodes, conditional jump, Opcode Extension
-	 * Groups, and some special opcodes can not boost.
-	 */
-static const u32 twobyte_is_boostable[256 / 32] = {
-	/*      0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f          */
-	/*      ----------------------------------------------          */
-	W(0x00, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0, 0, 0, 0, 0, 0) | /* 00 */
-	W(0x10, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 10 */
-	W(0x20, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) | /* 20 */
-	W(0x30, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 30 */
-	W(0x40, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* 40 */
-	W(0x50, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 50 */
-	W(0x60, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 1, 1) | /* 60 */
-	W(0x70, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1) , /* 70 */
-	W(0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) | /* 80 */
-	W(0x90, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* 90 */
-	W(0xa0, 1, 1, 0, 1, 1, 1, 0, 0, 1, 1, 0, 1, 1, 1, 0, 1) | /* a0 */
-	W(0xb0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 1, 1, 1, 1, 1) , /* b0 */
-	W(0xc0, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1) | /* c0 */
-	W(0xd0, 0, 1, 1, 1, 0, 1, 0, 0, 1, 1, 0, 1, 1, 1, 0, 1) , /* d0 */
-	W(0xe0, 0, 1, 1, 0, 0, 1, 0, 0, 1, 1, 0, 1, 1, 1, 0, 1) | /* e0 */
-	W(0xf0, 0, 1, 1, 1, 0, 1, 0, 0, 1, 1, 1, 0, 1, 1, 1, 0)   /* f0 */
-	/*      -----------------------------------------------         */
-	/*      0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f          */
-};
-static const u32 onebyte_has_modrm[256 / 32] = {
-	/*      0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f          */
-	/*      -----------------------------------------------         */
-	W(0x00, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0) | /* 00 */
-	W(0x10, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0) , /* 10 */
-	W(0x20, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0) | /* 20 */
-	W(0x30, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0) , /* 30 */
-	W(0x40, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) | /* 40 */
-	W(0x50, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 50 */
-	W(0x60, 0, 0, 1, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0) | /* 60 */
-	W(0x70, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 70 */
-	W(0x80, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* 80 */
-	W(0x90, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 90 */
-	W(0xa0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) | /* a0 */
-	W(0xb0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* b0 */
-	W(0xc0, 1, 1, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0) | /* c0 */
-	W(0xd0, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1) , /* d0 */
-	W(0xe0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) | /* e0 */
-	W(0xf0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1)   /* f0 */
-	/*      -----------------------------------------------         */
-	/*      0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f          */
-};
-static const u32 twobyte_has_modrm[256 / 32] = {
-	/*      0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f          */
-	/*      -----------------------------------------------         */
-	W(0x00, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1) | /* 0f */
-	W(0x10, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0) , /* 1f */
-	W(0x20, 1, 1, 1, 1, 1, 0, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1) | /* 2f */
-	W(0x30, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 3f */
-	W(0x40, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* 4f */
-	W(0x50, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* 5f */
-	W(0x60, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* 6f */
-	W(0x70, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 1, 1, 1, 1) , /* 7f */
-	W(0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) | /* 8f */
-	W(0x90, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* 9f */
-	W(0xa0, 0, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0, 1, 1, 1, 1, 1) | /* af */
-	W(0xb0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1, 1, 1) , /* bf */
-	W(0xc0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0) | /* cf */
-	W(0xd0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* df */
-	W(0xe0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* ef */
-	W(0xf0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0)   /* ff */
-	/*      -----------------------------------------------         */
-	/*      0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f          */
-};
-#undef W
-
-struct kretprobe_blackpoint kretprobe_blacklist[] = {
-	{"__switch_to", }, /* This function switches only current task, but
-			      doesn't switch kernel stack.*/
-	{NULL, NULL}	/* Terminator */
-};
-const int kretprobe_blacklist_size = ARRAY_SIZE(kretprobe_blacklist);
-
-/* Insert a jump instruction at address 'from', which jumps to address 'to'.*/
-static __always_inline void set_jmp_op(void *from, void *to)
-{
-	struct __arch_jmp_op {
-		char op;
-		s32 raddr;
-	} __attribute__((packed)) * jop;
-	jop = (struct __arch_jmp_op *)from;
-	jop->raddr = (s32)((long)(to) - ((long)(from) + 5));
-	jop->op = RELATIVEJUMP_INSTRUCTION;
-}
-
-/*
- * returns non-zero if opcode is boostable.
- */
-static __always_inline int can_boost(kprobe_opcode_t *opcodes)
-{
-	kprobe_opcode_t opcode;
-	kprobe_opcode_t *orig_opcodes = opcodes;
-
-retry:
-	if (opcodes - orig_opcodes > MAX_INSN_SIZE - 1)
-		return 0;
-	opcode = *(opcodes++);
-
-	/* 2nd-byte opcode */
-	if (opcode == 0x0f) {
-		if (opcodes - orig_opcodes > MAX_INSN_SIZE - 1)
-			return 0;
-		return test_bit(*opcodes,
-				(unsigned long *)twobyte_is_boostable);
-	}
-
-	switch (opcode & 0xf0) {
-	case 0x60:
-		if (0x63 < opcode && opcode < 0x67)
-			goto retry; /* prefixes */
-		/* can't boost Address-size override and bound */
-		return (opcode != 0x62 && opcode != 0x67);
-	case 0x70:
-		return 0; /* can't boost conditional jump */
-	case 0xc0:
-		/* can't boost software-interruptions */
-		return (0xc1 < opcode && opcode < 0xcc) || opcode == 0xcf;
-	case 0xd0:
-		/* can boost AA* and XLAT */
-		return (opcode == 0xd4 || opcode == 0xd5 || opcode == 0xd7);
-	case 0xe0:
-		/* can boost in/out and absolute jmps */
-		return ((opcode & 0x04) || opcode == 0xea);
-	case 0xf0:
-		if ((opcode & 0x0c) == 0 && opcode != 0xf1)
-			goto retry; /* lock/rep(ne) prefix */
-		/* clear and set flags are boostable */
-		return (opcode == 0xf5 || (0xf7 < opcode && opcode < 0xfe));
-	default:
-		/* segment override prefixes are boostable */
-		if (opcode == 0x26 || opcode == 0x36 || opcode == 0x3e)
-			goto retry; /* prefixes */
-		/* CS override prefix and call are not boostable */
-		return (opcode != 0x2e && opcode != 0x9a);
-	}
-}
-
-/*
- * returns non-zero if opcode modifies the interrupt flag.
- */
-static int __kprobes is_IF_modifier(kprobe_opcode_t *insn)
-{
-	switch (*insn) {
-	case 0xfa:		/* cli */
-	case 0xfb:		/* sti */
-	case 0xcf:		/* iret/iretd */
-	case 0x9d:		/* popf/popfd */
-		return 1;
-	}
-	return 0;
-}
-
-static void __kprobes arch_copy_kprobe(struct kprobe *p)
-{
-	memcpy(p->ainsn.insn, p->addr, MAX_INSN_SIZE * sizeof(kprobe_opcode_t));
-	if (can_boost(p->addr))
-		p->ainsn.boostable = 0;
-	else
-		p->ainsn.boostable = -1;
-
-	p->opcode = *p->addr;
-}
-
-int __kprobes arch_prepare_kprobe(struct kprobe *p)
-{
-	/* insn: must be on special executable page on x86. */
-	p->ainsn.insn = get_insn_slot();
-	if (!p->ainsn.insn)
-		return -ENOMEM;
-	arch_copy_kprobe(p);
-	return 0;
-}
-
-void __kprobes arch_arm_kprobe(struct kprobe *p)
-{
-	text_poke(p->addr, ((unsigned char []){BREAKPOINT_INSTRUCTION}), 1);
-}
-
-void __kprobes arch_disarm_kprobe(struct kprobe *p)
-{
-	text_poke(p->addr, &p->opcode, 1);
-}
-
-void __kprobes arch_remove_kprobe(struct kprobe *p)
-{
-	mutex_lock(&kprobe_mutex);
-	free_insn_slot(p->ainsn.insn, (p->ainsn.boostable == 1));
-	mutex_unlock(&kprobe_mutex);
-}
-
-static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)
-{
-	kcb->prev_kprobe.kp = kprobe_running();
-	kcb->prev_kprobe.status = kcb->kprobe_status;
-	kcb->prev_kprobe.old_flags = kcb->kprobe_old_flags;
-	kcb->prev_kprobe.saved_flags = kcb->kprobe_saved_flags;
-}
-
-static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb)
-{
-	__get_cpu_var(current_kprobe) = kcb->prev_kprobe.kp;
-	kcb->kprobe_status = kcb->prev_kprobe.status;
-	kcb->kprobe_old_flags = kcb->prev_kprobe.old_flags;
-	kcb->kprobe_saved_flags = kcb->prev_kprobe.saved_flags;
-}
-
-static void __kprobes set_current_kprobe(struct kprobe *p, struct pt_regs *regs,
-				struct kprobe_ctlblk *kcb)
-{
-	__get_cpu_var(current_kprobe) = p;
-	kcb->kprobe_saved_flags = kcb->kprobe_old_flags
-		= (regs->flags & (TF_MASK | IF_MASK));
-	if (is_IF_modifier(p->ainsn.insn))
-		kcb->kprobe_saved_flags &= ~IF_MASK;
-}
-
-static __always_inline void clear_btf(void)
-{
-	if (test_thread_flag(TIF_DEBUGCTLMSR))
-		wrmsr(MSR_IA32_DEBUGCTLMSR, 0, 0);
-}
-
-static __always_inline void restore_btf(void)
-{
-	if (test_thread_flag(TIF_DEBUGCTLMSR))
-		wrmsr(MSR_IA32_DEBUGCTLMSR, current->thread.debugctlmsr, 0);
-}
-
-static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs)
-{
-	clear_btf();
-	regs->flags |= TF_MASK;
-	regs->flags &= ~IF_MASK;
-	/*single step inline if the instruction is an int3*/
-	if (p->opcode == BREAKPOINT_INSTRUCTION)
-		regs->ip = (unsigned long)p->addr;
-	else
-		regs->ip = (unsigned long)p->ainsn.insn;
-}
-
-/* Called with kretprobe_lock held */
-void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
-				      struct pt_regs *regs)
-{
-	unsigned long *sara = stack_addr(regs);
-
-	ri->ret_addr = (kprobe_opcode_t *) *sara;
-
-	/* Replace the return addr with trampoline addr */
-	*sara = (unsigned long) &kretprobe_trampoline;
-}
-
-/*
- * Interrupts are disabled on entry as trap3 is an interrupt gate and they
- * remain disabled thorough out this function.
- */
-static int __kprobes kprobe_handler(struct pt_regs *regs)
-{
-	struct kprobe *p;
-	int ret = 0;
-	kprobe_opcode_t *addr;
-	struct kprobe_ctlblk *kcb;
-
-	addr = (kprobe_opcode_t *)(regs->ip - sizeof(kprobe_opcode_t));
-
-	/*
-	 * We don't want to be preempted for the entire
-	 * duration of kprobe processing
-	 */
-	preempt_disable();
-	kcb = get_kprobe_ctlblk();
-
-	/* Check we're not actually recursing */
-	if (kprobe_running()) {
-		p = get_kprobe(addr);
-		if (p) {
-			if (kcb->kprobe_status == KPROBE_HIT_SS &&
-				*p->ainsn.insn == BREAKPOINT_INSTRUCTION) {
-				regs->flags &= ~TF_MASK;
-				regs->flags |= kcb->kprobe_saved_flags;
-				goto no_kprobe;
-			}
-			/* We have reentered the kprobe_handler(), since
-			 * another probe was hit while within the handler.
-			 * We here save the original kprobes variables and
-			 * just single step on the instruction of the new probe
-			 * without calling any user handlers.
-			 */
-			save_previous_kprobe(kcb);
-			set_current_kprobe(p, regs, kcb);
-			kprobes_inc_nmissed_count(p);
-			prepare_singlestep(p, regs);
-			kcb->kprobe_status = KPROBE_REENTER;
-			return 1;
-		} else {
-			if (*addr != BREAKPOINT_INSTRUCTION) {
-			/* The breakpoint instruction was removed by
-			 * another cpu right after we hit, no further
-			 * handling of this interrupt is appropriate
-			 */
-				regs->ip = (unsigned long)addr;
-				ret = 1;
-				goto no_kprobe;
-			}
-			p = __get_cpu_var(current_kprobe);
-			if (p->break_handler && p->break_handler(p, regs)) {
-				goto ss_probe;
-			}
-		}
-		goto no_kprobe;
-	}
-
-	p = get_kprobe(addr);
-	if (!p) {
-		if (*addr != BREAKPOINT_INSTRUCTION) {
-			/*
-			 * The breakpoint instruction was removed right
-			 * after we hit it.  Another cpu has removed
-			 * either a probepoint or a debugger breakpoint
-			 * at this address.  In either case, no further
-			 * handling of this interrupt is appropriate.
-			 * Back up over the (now missing) int3 and run
-			 * the original instruction.
-			 */
-			regs->ip = (unsigned long)addr;
-			ret = 1;
-		}
-		/* Not one of ours: let kernel handle it */
-		goto no_kprobe;
-	}
-
-	set_current_kprobe(p, regs, kcb);
-	kcb->kprobe_status = KPROBE_HIT_ACTIVE;
-
-	if (p->pre_handler && p->pre_handler(p, regs))
-		/* handler has already set things up, so skip ss setup */
-		return 1;
-
-ss_probe:
-#if !defined(CONFIG_PREEMPT) || defined(CONFIG_PM)
-	if (p->ainsn.boostable == 1 && !p->post_handler) {
-		/* Boost up -- we can execute copied instructions directly */
-		reset_current_kprobe();
-		regs->ip = (unsigned long)p->ainsn.insn;
-		preempt_enable_no_resched();
-		return 1;
-	}
-#endif
-	prepare_singlestep(p, regs);
-	kcb->kprobe_status = KPROBE_HIT_SS;
-	return 1;
-
-no_kprobe:
-	preempt_enable_no_resched();
-	return ret;
-}
-
-/*
- * When a retprobed function returns, this code saves registers and
- * calls trampoline_handler() runs, which calls the kretprobe's handler.
- */
- void __kprobes kretprobe_trampoline_holder(void)
- {
-	asm volatile ( ".global kretprobe_trampoline\n"
-			"kretprobe_trampoline: \n"
-			"	pushf\n"
-			/*
-			 * Skip cs, ip, orig_ax.
-			 * trampoline_handler() will plug in these values
-			 */
-			"	subl $12, %esp\n"
-			"	pushl %fs\n"
-			"	pushl %ds\n"
-			"	pushl %es\n"
-			"	pushl %eax\n"
-			"	pushl %ebp\n"
-			"	pushl %edi\n"
-			"	pushl %esi\n"
-			"	pushl %edx\n"
-			"	pushl %ecx\n"
-			"	pushl %ebx\n"
-			"	movl %esp, %eax\n"
-			"	call trampoline_handler\n"
-			/* Move flags to cs */
-			"	movl 52(%esp), %edx\n"
-			"	movl %edx, 48(%esp)\n"
-			/* Replace saved flags with true return address. */
-			"	movl %eax, 52(%esp)\n"
-			"	popl %ebx\n"
-			"	popl %ecx\n"
-			"	popl %edx\n"
-			"	popl %esi\n"
-			"	popl %edi\n"
-			"	popl %ebp\n"
-			"	popl %eax\n"
-			/* Skip ip, orig_ax, es, ds, fs */
-			"	addl $20, %esp\n"
-			"	popf\n"
-			"	ret\n");
- }
-
-/*
- * Called from kretprobe_trampoline
- */
-void * __kprobes trampoline_handler(struct pt_regs *regs)
-{
-	struct kretprobe_instance *ri = NULL;
-	struct hlist_head *head, empty_rp;
-	struct hlist_node *node, *tmp;
-	unsigned long flags, orig_ret_address = 0;
-	unsigned long trampoline_address =(unsigned long)&kretprobe_trampoline;
-
-	INIT_HLIST_HEAD(&empty_rp);
-	spin_lock_irqsave(&kretprobe_lock, flags);
-	head = kretprobe_inst_table_head(current);
-	/* fixup registers */
-	regs->cs = __KERNEL_CS | get_kernel_rpl();
-	regs->ip = trampoline_address;
-	regs->orig_ax = ~0UL;
-
-	/*
-	 * It is possible to have multiple instances associated with a given
-	 * task either because multiple functions in the call path have
-	 * return probes installed on them, and/or more then one
-	 * return probe was registered for a target function.
-	 *
-	 * We can handle this because:
-	 *     - instances are always pushed into the head of the list
-	 *     - when multiple return probes are registered for the same
-	 *	 function, the (chronologically) first instance's ret_addr
-	 *	 will be the real return address, and all the rest will
-	 *	 point to kretprobe_trampoline.
-	 */
-	hlist_for_each_entry_safe(ri, node, tmp, head, hlist) {
-		if (ri->task != current)
-			/* another task is sharing our hash bucket */
-			continue;
-
-		if (ri->rp && ri->rp->handler) {
-			__get_cpu_var(current_kprobe) = &ri->rp->kp;
-			get_kprobe_ctlblk()->kprobe_status = KPROBE_HIT_ACTIVE;
-			ri->rp->handler(ri, regs);
-			__get_cpu_var(current_kprobe) = NULL;
-		}
-
-		orig_ret_address = (unsigned long)ri->ret_addr;
-		recycle_rp_inst(ri, &empty_rp);
-
-		if (orig_ret_address != trampoline_address)
-			/*
-			 * This is the real return address. Any other
-			 * instances associated with this task are for
-			 * other calls deeper on the call stack
-			 */
-			break;
-	}
-
-	kretprobe_assert(ri, orig_ret_address, trampoline_address);
-
-	spin_unlock_irqrestore(&kretprobe_lock, flags);
-
-	hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) {
-		hlist_del(&ri->hlist);
-		kfree(ri);
-	}
-	return (void *)orig_ret_address;
-}
-
-/*
- * Called after single-stepping.  p->addr is the address of the
- * instruction whose first byte has been replaced by the "int 3"
- * instruction.  To avoid the SMP problems that can occur when we
- * temporarily put back the original opcode to single-step, we
- * single-stepped a copy of the instruction.  The address of this
- * copy is p->ainsn.insn.
- *
- * This function prepares to return from the post-single-step
- * interrupt.  We have to fix up the stack as follows:
- *
- * 0) Except in the case of absolute or indirect jump or call instructions,
- * the new ip is relative to the copied instruction.  We need to make
- * it relative to the original instruction.
- *
- * 1) If the single-stepped instruction was pushfl, then the TF and IF
- * flags are set in the just-pushed flags, and may need to be cleared.
- *
- * 2) If the single-stepped instruction was a call, the return address
- * that is atop the stack is the address following the copied instruction.
- * We need to make it the address following the original instruction.
- *
- * If this is the first time we've single-stepped the instruction at
- * this probepoint, and the instruction is boostable, boost it: add a
- * jump instruction after the copied instruction, that jumps to the next
- * instruction after the probepoint.
- */
-static void __kprobes resume_execution(struct kprobe *p,
-		struct pt_regs *regs, struct kprobe_ctlblk *kcb)
-{
-	unsigned long *tos = stack_addr(regs);
-	unsigned long copy_ip = (unsigned long)p->ainsn.insn;
-	unsigned long orig_ip = (unsigned long)p->addr;
-	kprobe_opcode_t *insn = p->ainsn.insn;
-
-	regs->flags &= ~TF_MASK;
-	switch (*insn) {
-	case 0x9c:	/* pushfl */
-		*tos &= ~(TF_MASK | IF_MASK);
-		*tos |= kcb->kprobe_old_flags;
-		break;
-	case 0xc2:	/* iret/ret/lret */
-	case 0xc3:
-	case 0xca:
-	case 0xcb:
-	case 0xcf:
-	case 0xea:	/* jmp absolute -- ip is correct */
-		/* ip is already adjusted, no more changes required */
-		p->ainsn.boostable = 1;
-		goto no_change;
-	case 0xe8:	/* call relative - Fix return addr */
-		*tos = orig_ip + (*tos - copy_ip);
-		break;
-	case 0x9a:	/* call absolute -- same as call absolute, indirect */
-		*tos = orig_ip + (*tos - copy_ip);
-		goto no_change;
-	case 0xff:
-		if ((insn[1] & 0x30) == 0x10) {
-			/*
-			 * call absolute, indirect
-			 * Fix return addr; ip is correct.
-			 * But this is not boostable
-			 */
-			*tos = orig_ip + (*tos - copy_ip);
-			goto no_change;
-		} else if (((insn[1] & 0x31) == 0x20) ||
-			   ((insn[1] & 0x31) == 0x21)) {
-			/*
-			 * jmp near and far, absolute indirect
-			 * ip is correct. And this is boostable
-			 */
-			p->ainsn.boostable = 1;
-			goto no_change;
-		}
-	default:
-		break;
-	}
-
-	if (p->ainsn.boostable == 0) {
-		if ((regs->ip > copy_ip) &&
-		    (regs->ip - copy_ip) + 5 < MAX_INSN_SIZE) {
-			/*
-			 * These instructions can be executed directly if it
-			 * jumps back to correct address.
-			 */
-			set_jmp_op((void *)regs->ip,
-				   (void *)orig_ip + (regs->ip - copy_ip));
-			p->ainsn.boostable = 1;
-		} else {
-			p->ainsn.boostable = -1;
-		}
-	}
-
-	regs->ip += orig_ip - copy_ip;
-
-no_change:
-	restore_btf();
-
-	return;
-}
-
-/*
- * Interrupts are disabled on entry as trap1 is an interrupt gate and they
- * remain disabled thoroughout this function.
- */
-static int __kprobes post_kprobe_handler(struct pt_regs *regs)
-{
-	struct kprobe *cur = kprobe_running();
-	struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
-
-	if (!cur)
-		return 0;
-
-	if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) {
-		kcb->kprobe_status = KPROBE_HIT_SSDONE;
-		cur->post_handler(cur, regs, 0);
-	}
-
-	resume_execution(cur, regs, kcb);
-	regs->flags |= kcb->kprobe_saved_flags;
-	trace_hardirqs_fixup_flags(regs->flags);
-
-	/* Restore back the original saved kprobes variables and continue. */
-	if (kcb->kprobe_status == KPROBE_REENTER) {
-		restore_previous_kprobe(kcb);
-		goto out;
-	}
-	reset_current_kprobe();
-out:
-	preempt_enable_no_resched();
-
-	/*
-	 * if somebody else is singlestepping across a probe point, flags
-	 * will have TF set, in which case, continue the remaining processing
-	 * of do_debug, as if this is not a probe hit.
-	 */
-	if (regs->flags & TF_MASK)
-		return 0;
-
-	return 1;
-}
-
-int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
-{
-	struct kprobe *cur = kprobe_running();
-	struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
-
-	switch(kcb->kprobe_status) {
-	case KPROBE_HIT_SS:
-	case KPROBE_REENTER:
-		/*
-		 * We are here because the instruction being single
-		 * stepped caused a page fault. We reset the current
-		 * kprobe and the ip points back to the probe address
-		 * and allow the page fault handler to continue as a
-		 * normal page fault.
-		 */
-		regs->ip = (unsigned long)cur->addr;
-		regs->flags |= kcb->kprobe_old_flags;
-		if (kcb->kprobe_status == KPROBE_REENTER)
-			restore_previous_kprobe(kcb);
-		else
-			reset_current_kprobe();
-		preempt_enable_no_resched();
-		break;
-	case KPROBE_HIT_ACTIVE:
-	case KPROBE_HIT_SSDONE:
-		/*
-		 * We increment the nmissed count for accounting,
-		 * we can also use npre/npostfault count for accounting
-		 * these specific fault cases.
-		 */
-		kprobes_inc_nmissed_count(cur);
-
-		/*
-		 * We come here because instructions in the pre/post
-		 * handler caused the page_fault, this could happen
-		 * if handler tries to access user space by
-		 * copy_from_user(), get_user() etc. Let the
-		 * user-specified handler try to fix it first.
-		 */
-		if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr))
-			return 1;
-
-		/*
-		 * In case the user-specified fault handler returned
-		 * zero, try to fix up.
-		 */
-		if (fixup_exception(regs))
-			return 1;
-
-		/*
-		 * fixup routine could not handle it,
-		 * Let do_page_fault() fix it.
-		 */
-		break;
-	default:
-		break;
-	}
-	return 0;
-}
-
-/*
- * Wrapper routine for handling exceptions.
- */
-int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
-				       unsigned long val, void *data)
-{
-	struct die_args *args = (struct die_args *)data;
-	int ret = NOTIFY_DONE;
-
-	if (args->regs && user_mode_vm(args->regs))
-		return ret;
-
-	switch (val) {
-	case DIE_INT3:
-		if (kprobe_handler(args->regs))
-			ret = NOTIFY_STOP;
-		break;
-	case DIE_DEBUG:
-		if (post_kprobe_handler(args->regs))
-			ret = NOTIFY_STOP;
-		break;
-	case DIE_GPF:
-		/* kprobe_running() needs smp_processor_id() */
-		preempt_disable();
-		if (kprobe_running() &&
-		    kprobe_fault_handler(args->regs, args->trapnr))
-			ret = NOTIFY_STOP;
-		preempt_enable();
-		break;
-	default:
-		break;
-	}
-	return ret;
-}
-
-int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
-{
-	struct jprobe *jp = container_of(p, struct jprobe, kp);
-	unsigned long addr;
-	struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
-
-	kcb->jprobe_saved_regs = *regs;
-	kcb->jprobe_saved_sp = stack_addr(regs);
-	addr = (unsigned long)(kcb->jprobe_saved_sp);
-
-	/*
-	 * As Linus pointed out, gcc assumes that the callee
-	 * owns the argument space and could overwrite it, e.g.
-	 * tailcall optimization. So, to be absolutely safe
-	 * we also save and restore enough stack bytes to cover
-	 * the argument area.
-	 */
-	memcpy(kcb->jprobes_stack, (kprobe_opcode_t *)addr,
-			MIN_STACK_SIZE(addr));
-	regs->flags &= ~IF_MASK;
-	trace_hardirqs_off();
-	regs->ip = (unsigned long)(jp->entry);
-	return 1;
-}
-
-void __kprobes jprobe_return(void)
-{
-	struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
-
-	asm volatile ("       xchgl   %%ebx,%%esp     \n"
-		      "       int3			\n"
-		      "       .globl jprobe_return_end	\n"
-		      "       jprobe_return_end:	\n"
-		      "       nop			\n"::"b"
-		      (kcb->jprobe_saved_sp):"memory");
-}
-
-int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
-{
-	struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
-	u8 *addr = (u8 *) (regs->ip - 1);
-	struct jprobe *jp = container_of(p, struct jprobe, kp);
-
-	if ((addr > (u8 *) jprobe_return) && (addr < (u8 *) jprobe_return_end)) {
-		if (stack_addr(regs) != kcb->jprobe_saved_sp) {
-			struct pt_regs *saved_regs = &kcb->jprobe_saved_regs;
-			printk("current sp %p does not match saved sp %p\n",
-			       stack_addr(regs), kcb->jprobe_saved_sp);
-			printk("Saved registers for jprobe %p\n", jp);
-			show_registers(saved_regs);
-			printk("Current registers\n");
-			show_registers(regs);
-			BUG();
-		}
-		*regs = kcb->jprobe_saved_regs;
-		memcpy((kprobe_opcode_t *)(kcb->jprobe_saved_sp),
-		       kcb->jprobes_stack,
-		       MIN_STACK_SIZE(kcb->jprobe_saved_sp));
-		preempt_enable_no_resched();
-		return 1;
-	}
-	return 0;
-}
-
-int __init arch_init_kprobes(void)
-{
-	return 0;
-}
-
-int __kprobes arch_trampoline_kprobe(struct kprobe *p)
-{
-	return 0;
-}

include/asm-x86/kprobes.h

@@ -1,5 +1,98 @@
-#ifdef CONFIG_X86_32
-# include "kprobes_32.h"
-#else
-# include "kprobes_64.h"
-#endif
+#ifndef _ASM_KPROBES_H
+#define _ASM_KPROBES_H
+/*
+ *  Kernel Probes (KProbes)
+ *
+ * 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.
+ *
+ * Copyright (C) IBM Corporation, 2002, 2004
+ *
+ * See arch/x86/kernel/kprobes.c for x86 kprobes history.
+ */
+#include <linux/types.h>
+#include <linux/ptrace.h>
+#include <linux/percpu.h>
+
+#define  __ARCH_WANT_KPROBES_INSN_SLOT
+
+struct pt_regs;
+struct kprobe;
+
+typedef u8 kprobe_opcode_t;
+#define BREAKPOINT_INSTRUCTION	0xcc
+#define RELATIVEJUMP_INSTRUCTION 0xe9
+#define MAX_INSN_SIZE 16
+#define MAX_STACK_SIZE 64
+#define MIN_STACK_SIZE(ADDR) (((MAX_STACK_SIZE) < \
+	(((unsigned long)current_thread_info()) + THREAD_SIZE \
+	 - (unsigned long)(ADDR))) \
+	? (MAX_STACK_SIZE) \
+	: (((unsigned long)current_thread_info()) + THREAD_SIZE \
+	   - (unsigned long)(ADDR)))
+
+#define ARCH_SUPPORTS_KRETPROBES
+#define flush_insn_slot(p)	do { } while (0)
+
+extern const int kretprobe_blacklist_size;
+
+void arch_remove_kprobe(struct kprobe *p);
+void kretprobe_trampoline(void);
+
+/* Architecture specific copy of original instruction*/
+struct arch_specific_insn {
+	/* copy of the original instruction */
+	kprobe_opcode_t *insn;
+	/*
+	 * boostable = -1: This instruction type is not boostable.
+	 * boostable = 0: This instruction type is boostable.
+	 * boostable = 1: This instruction has been boosted: we have
+	 * added a relative jump after the instruction copy in insn,
+	 * so no single-step and fixup are needed (unless there's
+	 * a post_handler or break_handler).
+	 */
+	int boostable;
+};
+
+struct prev_kprobe {
+	struct kprobe *kp;
+	unsigned long status;
+	unsigned long old_flags;
+	unsigned long saved_flags;
+};
+
+/* per-cpu kprobe control block */
+struct kprobe_ctlblk {
+	unsigned long kprobe_status;
+	unsigned long kprobe_old_flags;
+	unsigned long kprobe_saved_flags;
+	unsigned long *jprobe_saved_sp;
+	struct pt_regs jprobe_saved_regs;
+	kprobe_opcode_t jprobes_stack[MAX_STACK_SIZE];
+	struct prev_kprobe prev_kprobe;
+};
+
+/* trap3/1 are intr gates for kprobes.  So, restore the status of IF,
+ * if necessary, before executing the original int3/1 (trap) handler.
+ */
+static inline void restore_interrupts(struct pt_regs *regs)
+{
+	if (regs->flags & IF_MASK)
+		local_irq_enable();
+}
+
+extern int kprobe_fault_handler(struct pt_regs *regs, int trapnr);
+extern int kprobe_exceptions_notify(struct notifier_block *self,
+				    unsigned long val, void *data);
+#endif				/* _ASM_KPROBES_H */

include/asm-x86/kprobes_32.h

@@ -1,102 +0,0 @@
-#ifndef _ASM_KPROBES_H
-#define _ASM_KPROBES_H
-/*
- *  Kernel Probes (KProbes)
- *
- * 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.
- *
- * Copyright (C) IBM Corporation, 2002, 2004
- *
- * 2002-Oct	Created by Vamsi Krishna S <vamsi_krishna@in.ibm.com> Kernel
- *		Probes initial implementation ( includes suggestions from
- *		Rusty Russell).
- * 2004-Oct	Prasanna S Panchamukhi <prasanna@in.ibm.com> and Jim Keniston
- *		kenistoj@us.ibm.com adopted from i386.
- */
-#include <linux/types.h>
-#include <linux/ptrace.h>
-#include <linux/percpu.h>
-
-#define  __ARCH_WANT_KPROBES_INSN_SLOT
-
-struct pt_regs;
-struct kprobe;
-
-typedef u8 kprobe_opcode_t;
-#define BREAKPOINT_INSTRUCTION	0xcc
-#define RELATIVEJUMP_INSTRUCTION 0xe9
-#define MAX_INSN_SIZE 16
-#define MAX_STACK_SIZE 64
-#define MIN_STACK_SIZE(ADDR) (((MAX_STACK_SIZE) < \
-	(((unsigned long)current_thread_info()) + THREAD_SIZE \
-	 - (unsigned long)(ADDR))) \
-	? (MAX_STACK_SIZE) \
-	: (((unsigned long)current_thread_info()) + THREAD_SIZE \
-	   - (unsigned long)(ADDR)))
-
-#define ARCH_SUPPORTS_KRETPROBES
-#define flush_insn_slot(p)	do { } while (0)
-
-extern const int kretprobe_blacklist_size;
-
-void arch_remove_kprobe(struct kprobe *p);
-void kretprobe_trampoline(void);
-
-/* Architecture specific copy of original instruction*/
-struct arch_specific_insn {
-	/* copy of the original instruction */
-	kprobe_opcode_t *insn;
-	/*
-	 * boostable = -1: This instruction type is not boostable.
-	 * boostable = 0: This instruction type is boostable.
-	 * boostable = 1: This instruction has been boosted: we have
-	 * added a relative jump after the instruction copy in insn,
-	 * so no single-step and fixup are needed (unless there's
-	 * a post_handler or break_handler).
-	 */
-	int boostable;
-};
-
-struct prev_kprobe {
-	struct kprobe *kp;
-	unsigned long status;
-	unsigned long old_flags;
-	unsigned long saved_flags;
-};
-
-/* per-cpu kprobe control block */
-struct kprobe_ctlblk {
-	unsigned long kprobe_status;
-	unsigned long kprobe_old_flags;
-	unsigned long kprobe_saved_flags;
-	unsigned long *jprobe_saved_sp;
-	struct pt_regs jprobe_saved_regs;
-	kprobe_opcode_t jprobes_stack[MAX_STACK_SIZE];
-	struct prev_kprobe prev_kprobe;
-};
-
-/* trap3/1 are intr gates for kprobes.  So, restore the status of IF,
- * if necessary, before executing the original int3/1 (trap) handler.
- */
-static inline void restore_interrupts(struct pt_regs *regs)
-{
-	if (regs->flags & IF_MASK)
-		local_irq_enable();
-}
-
-extern int kprobe_fault_handler(struct pt_regs *regs, int trapnr);
-extern int kprobe_exceptions_notify(struct notifier_block *self,
-				    unsigned long val, void *data);
-#endif				/* _ASM_KPROBES_H */

include/asm-x86/kprobes_64.h

@@ -1,102 +0,0 @@
-#ifndef _ASM_KPROBES_H
-#define _ASM_KPROBES_H
-/*
- *  Kernel Probes (KProbes)
- *
- * 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.
- *
- * Copyright (C) IBM Corporation, 2002, 2004
- *
- * 2002-Oct	Created by Vamsi Krishna S <vamsi_krishna@in.ibm.com> Kernel
- *		Probes initial implementation ( includes suggestions from
- *		Rusty Russell).
- * 2004-Oct	Prasanna S Panchamukhi <prasanna@in.ibm.com> and Jim Keniston
- *		kenistoj@us.ibm.com adopted from i386.
- */
-#include <linux/types.h>
-#include <linux/ptrace.h>
-#include <linux/percpu.h>
-
-#define  __ARCH_WANT_KPROBES_INSN_SLOT
-
-struct pt_regs;
-struct kprobe;
-
-typedef u8 kprobe_opcode_t;
-#define BREAKPOINT_INSTRUCTION	0xcc
-#define RELATIVEJUMP_INSTRUCTION 0xe9
-#define MAX_INSN_SIZE 16
-#define MAX_STACK_SIZE 64
-#define MIN_STACK_SIZE(ADDR) (((MAX_STACK_SIZE) < \
-	(((unsigned long)current_thread_info()) + THREAD_SIZE \
-	 - (unsigned long)(ADDR))) \
-	? (MAX_STACK_SIZE) \
-	: (((unsigned long)current_thread_info()) + THREAD_SIZE \
-	   - (unsigned long)(ADDR)))
-
-#define ARCH_SUPPORTS_KRETPROBES
-#define flush_insn_slot(p)	do { } while (0)
-
-extern const int kretprobe_blacklist_size;
-
-void arch_remove_kprobe(struct kprobe *p);
-void kretprobe_trampoline(void);
-
-/* Architecture specific copy of original instruction*/
-struct arch_specific_insn {
-	/* copy of the original instruction */
-	kprobe_opcode_t *insn;
-	/*
-	 * boostable = -1: This instruction type is not boostable.
-	 * boostable = 0: This instruction type is boostable.
-	 * boostable = 1: This instruction has been boosted: we have
-	 * added a relative jump after the instruction copy in insn,
-	 * so no single-step and fixup are needed (unless there's
-	 * a post_handler or break_handler).
-	 */
-	int boostable;
-};
-
-struct prev_kprobe {
-	struct kprobe *kp;
-	unsigned long status;
-	unsigned long old_flags;
-	unsigned long saved_flags;
-};
-
-/* per-cpu kprobe control block */
-struct kprobe_ctlblk {
-	unsigned long kprobe_status;
-	unsigned long kprobe_old_flags;
-	unsigned long kprobe_saved_flags;
-	unsigned long *jprobe_saved_sp;
-	struct pt_regs jprobe_saved_regs;
-	kprobe_opcode_t jprobes_stack[MAX_STACK_SIZE];
-	struct prev_kprobe prev_kprobe;
-};
-
-/* trap3/1 are intr gates for kprobes.  So, restore the status of IF,
- * if necessary, before executing the original int3/1 (trap) handler.
- */
-static inline void restore_interrupts(struct pt_regs *regs)
-{
-	if (regs->flags & IF_MASK)
-		local_irq_enable();
-}
-
-extern int kprobe_fault_handler(struct pt_regs *regs, int trapnr);
-extern int kprobe_exceptions_notify(struct notifier_block *self,
-				    unsigned long val, void *data);
-#endif				/* _ASM_KPROBES_H */