linux-kernel - [PATCH] x86: Unify kpropes MAX_INSN

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Date:	Fri, 14 Dec 2007 14:10:32 -0800
From:	Harvey Harrison <harvey.harrison@...il.com>
To:	Ingo Molnar <mingo@...e.hu>
Cc:	"H. Peter Anvin" <hpa@...or.com>,
	LKML <linux-kernel@...r.kernel.org>,
	Thomas Gleixner <tglx@...utronix.de>
Subject: [PATCH] x86: Unify kpropes MAX_INSN_SIZE definition

Signed-off-by: Harvey Harrison <harvey.harrison@...il.com>
---
 arch/x86/kernel/kprobes_32.c |    8 ++++----
 include/asm-x86/kprobes.h    |    5 +----
 2 files changed, 5 insertions(+), 8 deletions(-)

diff --git a/arch/x86/kernel/kprobes_32.c b/arch/x86/kernel/kprobes_32.c
index b47381e..615f24a 100644
--- a/arch/x86/kernel/kprobes_32.c
+++ b/arch/x86/kernel/kprobes_32.c
@@ -101,13 +101,13 @@ 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)
+	if (opcodes - orig_opcodes > MAX_INSN_SIZE)
 		return 0;
 	opcode = *(opcodes++);
 
 	/* 2nd-byte opcode */
 	if (opcode == 0x0f) {
-		if (opcodes - orig_opcodes > MAX_INSN_SIZE - 1)
+		if (opcodes - orig_opcodes > MAX_INSN_SIZE)
 			return 0;
 		return test_bit(*opcodes, twobyte_is_boostable);
 	}
@@ -164,7 +164,7 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p)
 	if (!p->ainsn.insn)
 		return -ENOMEM;
 
-	memcpy(p->ainsn.insn, p->addr, MAX_INSN_SIZE * sizeof(kprobe_opcode_t));
+	memcpy(p->ainsn.insn, p->addr, (MAX_INSN_SIZE + 1) * sizeof(kprobe_opcode_t));
 	p->opcode = *p->addr;
 	if (can_boost(p->addr)) {
 		p->ainsn.boostable = 0;
@@ -539,7 +539,7 @@ static void __kprobes resume_execution(struct kprobe *p,
 
 	if (p->ainsn.boostable == 0) {
 		if ((regs->ip > copy_eip) &&
-		    (regs->ip - copy_eip) + 5 < MAX_INSN_SIZE) {
+		    (regs->ip - copy_eip) + 5 < (MAX_INSN_SIZE + 1)) {
 			/*
 			 * These instructions can be executed directly if it
 			 * jumps back to correct address.
diff --git a/include/asm-x86/kprobes.h b/include/asm-x86/kprobes.h
index 87b9d1b..e348ed6 100644
--- a/include/asm-x86/kprobes.h
+++ b/include/asm-x86/kprobes.h
@@ -35,12 +35,9 @@ struct kprobe;
 struct pt_regs;
 
 typedef u8 kprobe_opcode_t;
-#ifdef CONFIG_X86_32
+
 # define RELATIVEJUMP_INSTRUCTION 0xe9
-# define MAX_INSN_SIZE 16
-#else
 # define MAX_INSN_SIZE 15
-#endif
 
 #define BREAKPOINT_INSTRUCTION	0xcc
 #define MAX_STACK_SIZE 64
-- 
1.5.4.rc0.1083.gf568



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