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[PATCH][1/2] kprobe: kprobe-booster against 2.6.16-rc1 for i386
- From: Masami Hiramatsu <hiramatu at sdl dot hitachi dot co dot jp>
- To: Andrew Morton <akpm at osdl dot org>, Ananth N Mavinakayanahalli <ananth at in dot ibm dot com>, Prasanna S Panchamukhi <prasanna at in dot ibm dot com>, "Keshavamurthy, Anil S" <anil dot s dot keshavamurthy at intel dot com>
- Cc: SystemTAP <systemtap at sources dot redhat dot com>, Jim Keniston <jkenisto at us dot ibm dot com>, linux-kernel at vger dot kernel dot org, Yumiko Sugita <sugita at sdl dot hitachi dot co dot jp>, Satoshi Oshima <soshima at redhat dot com>, Hideo Aoki <haoki at redhat dot com>
- Date: Mon, 30 Jan 2006 21:44:49 +0900
- Subject: [PATCH][1/2] kprobe: kprobe-booster against 2.6.16-rc1 for i386
Hi, Andrew
Here is a patch to clean up kprobe's resume_execute() for i386 arch
against linux-2.6.16-rc1 and also appliable against 2.6.16-rc1-mm4.
Before applying kprobe-booster, I'd like to cleanup codes. It is useful
to simplify (and easy to understand) kprobe-booster patch.
Best Regards,
--
Masami HIRAMATSU
2nd Research Dept.
Hitachi, Ltd., Systems Development Laboratory
E-mail: hiramatu@sdl.hitachi.co.jp
Signed-off-by: Masami Hiramatsu <hiramatu@sdl.hitachi.co.jp>
kprobes.c | 26 ++++++++++----------------
1 files changed, 10 insertions(+), 16 deletions(-)
diff -Narup a/arch/i386/kernel/kprobes.c b/arch/i386/kernel/kprobes.c
--- a/arch/i386/kernel/kprobes.c 2006-01-24 19:07:26.000000000 +0900
+++ b/arch/i386/kernel/kprobes.c 2006-01-30 18:17:17.000000000 +0900
@@ -350,10 +350,10 @@ static void __kprobes resume_execution(s
struct pt_regs *regs, struct kprobe_ctlblk *kcb)
{
unsigned long *tos = (unsigned long *)®s->esp;
- unsigned long next_eip = 0;
unsigned long copy_eip = (unsigned long)&p->ainsn.insn;
unsigned long orig_eip = (unsigned long)p->addr;
+ regs->eflags &= ~TF_MASK;
switch (p->ainsn.insn[0]) {
case 0x9c: /* pushfl */
*tos &= ~(TF_MASK | IF_MASK);
@@ -363,9 +363,9 @@ static void __kprobes resume_execution(s
case 0xcb:
case 0xc2:
case 0xca:
- regs->eflags &= ~TF_MASK;
- /* eip is already adjusted, no more changes required*/
- return;
+ case 0xea: /* jmp absolute -- eip is correct */
+ /* eip is already adjusted, no more changes required */
+ goto no_change;
case 0xe8: /* call relative - Fix return addr */
*tos = orig_eip + (*tos - copy_eip);
break;
@@ -373,27 +373,21 @@ static void __kprobes resume_execution(s
if ((p->ainsn.insn[1] & 0x30) == 0x10) {
/* call absolute, indirect */
/* Fix return addr; eip is correct. */
- next_eip = regs->eip;
*tos = orig_eip + (*tos - copy_eip);
+ goto no_change;
} else if (((p->ainsn.insn[1] & 0x31) == 0x20) || /* jmp near, absolute indirect */
((p->ainsn.insn[1] & 0x31) == 0x21)) { /* jmp far, absolute indirect */
/* eip is correct. */
- next_eip = regs->eip;
+ goto no_change;
}
- break;
- case 0xea: /* jmp absolute -- eip is correct */
- next_eip = regs->eip;
- break;
default:
break;
}
- regs->eflags &= ~TF_MASK;
- if (next_eip) {
- regs->eip = next_eip;
- } else {
- regs->eip = orig_eip + (regs->eip - copy_eip);
- }
+ regs->eip = orig_eip + (regs->eip - copy_eip);
+
+no_change:
+ return;
}
/*