[PATCH] kretprobe: kretprobe-booster against 2.6.16-rc1 for i386

From: Masami Hiramatsu
Date: Mon Jan 30 2006 - 07:43:29 EST


Hi, Andrew

Here is a patch of the kretprobe-booster for i386 arch against
linux-2.6.16-rc1 and also appliable against 2.6.16-rc1-mm4.

Best Regards,

--
Masami HIRAMATSU
2nd Research Dept.
Hitachi, Ltd., Systems Development Laboratory
E-mail: hiramatu@xxxxxxxxxxxxxxxxx

Signed-off-by: Masami Hiramatsu <hiramatu@xxxxxxxxxxxxxxxxx>

kprobes.c | 56 ++++++++++++++++++++++++++++++++++++--------------------
1 files changed, 36 insertions(+), 20 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 18:40:12.000000000 +0900
@@ -255,17 +255,45 @@ no_kprobe:
* here. When a retprobed function returns, this probe is hit and
* trampoline_probe_handler() runs, calling the kretprobe's handler.
*/
- void kretprobe_trampoline_holder(void)
+ void __kprobes kretprobe_trampoline_holder(void)
{
- asm volatile ( ".global kretprobe_trampoline\n"
+ asm volatile ( ".global kretprobe_trampoline\n"
"kretprobe_trampoline: \n"
- "nop\n");
- }
+ " subl $8, %esp\n"
+ " pushf\n"
+ " subl $20, %esp\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"
+ " pushl %eax\n"
+ " addl $60, %eax\n"
+ " movl %eax, 56(%esp)\n"
+ " movl $trampoline_handler, %eax\n"
+ " call *%eax\n"
+ " addl $4, %esp\n"
+ " movl %eax, 56(%esp)\n"
+ " popl %ebx\n"
+ " popl %ecx\n"
+ " popl %edx\n"
+ " popl %esi\n"
+ " popl %edi\n"
+ " popl %ebp\n"
+ " popl %eax\n"
+ " addl $20, %esp\n"
+ " popf\n"
+ " addl $4, %esp\n"
+ " ret\n");
+}

/*
- * Called when we hit the probe point at kretprobe_trampoline
+ * Called from kretprobe_trampoline
*/
-int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
+asmlinkage void *__kprobes trampoline_handler(struct pt_regs *regs)
{
struct kretprobe_instance *ri = NULL;
struct hlist_head *head;
@@ -310,18 +338,11 @@ int __kprobes trampoline_probe_handler(s
}

BUG_ON(!orig_ret_address || (orig_ret_address == trampoline_address));
- regs->eip = orig_ret_address;

- reset_current_kprobe();
spin_unlock_irqrestore(&kretprobe_lock, flags);
preempt_enable_no_resched();

- /*
- * By returning a non-zero value, we are telling
- * kprobe_handler() that we don't want the post_handler
- * to run (and have re-enabled preemption)
- */
- return 1;
+ return (void*)orig_ret_address;
}

/*
@@ -552,12 +573,7 @@ int __kprobes longjmp_break_handler(stru
return 0;
}

-static struct kprobe trampoline_p = {
- .addr = (kprobe_opcode_t *) &kretprobe_trampoline,
- .pre_handler = trampoline_probe_handler
-};
-
int __init arch_init_kprobes(void)
{
- return register_kprobe(&trampoline_p);
+ return 0;
}





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