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Re: [PATCH] kretprobe: kretprobe-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: Masami Hiramatsu <hiramatu at sdl dot hitachi dot co dot jp>, 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: Tue, 31 Jan 2006 10:45:34 +0900
- Subject: Re: [PATCH] kretprobe: kretprobe-booster against 2.6.16-rc1 for i386
- References: <43DE0A53.3060801@sdl.hitachi.co.jp>
Sorry, also I forgot to remove a solo decrement routine.
Masami Hiramatsu wrote:
> @@ -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();
^^^^^^^^^^^^^^^^^^^^^^^^^^^^ This must cause a trouble.
So, I must remove it (when boosting)
> - preempt_enable_no_resched();
I attatch the fixed patch to this mail.
>
> - /*
> - * 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;
> }
>
> /*
--
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 | 57 ++++++++++++++++++++++++++++++++++++---------------------
1 files changed, 36 insertions(+), 21 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 2006-01-31 10:26:46.000000000 +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 +338,10 @@ 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 +572,7 @@ 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;
}