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[RFC PATCH 1/4] kprobes: i386 specific preempt changes
- From: Ananth N Mavinakayanahalli <ananth at in dot ibm dot com>
- To: systemtap at sources dot redhat dot com
- Date: Fri, 29 Jul 2005 14:30:45 -0400
- Subject: [RFC PATCH 1/4] kprobes: i386 specific preempt changes
- References: <20050729182840.GA1692@in.ibm.com>
- Reply-to: ananth at in dot ibm dot com
i386 specific changes for preempt/(dis/en)able()
Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
arch/i386/kernel/kprobes.c | 25 +++++++++++++------------
1 files changed, 13 insertions(+), 12 deletions(-)
Index: linux-2.6.13-rc3/arch/i386/kernel/kprobes.c
===================================================================
--- linux-2.6.13-rc3.orig/arch/i386/kernel/kprobes.c 2005-07-27 13:11:04.000000000 -0400
+++ linux-2.6.13-rc3/arch/i386/kernel/kprobes.c 2005-07-27 13:26:31.000000000 -0400
@@ -158,8 +158,6 @@ static int __kprobes kprobe_handler(stru
kprobe_opcode_t *addr = NULL;
unsigned long *lp;
- /* We're in an interrupt, but this is clear and BUG()-safe. */
- preempt_disable();
/* Check if the application is using LDT entry for its code segment and
* calculate the address by reading the base address from the LDT entry.
*/
@@ -238,6 +236,11 @@ static int __kprobes kprobe_handler(stru
ss_probe:
prepare_singlestep(p, regs);
kprobe_status = KPROBE_HIT_SS;
+ /*
+ * This preempt_disable() matches the preempt_enable_no_resched()
+ * in post_kprobe_handler()
+ */
+ preempt_disable();
return 1;
no_kprobe:
@@ -307,7 +310,6 @@ int __kprobes trampoline_probe_handler(s
regs->eip = orig_ret_address;
unlock_kprobes();
- preempt_enable_no_resched();
/*
* By returning a non-zero value, we are telling
@@ -449,29 +451,29 @@ int __kprobes kprobe_exceptions_notify(s
unsigned long val, void *data)
{
struct die_args *args = (struct die_args *)data;
+ int ret = NOTIFY_DONE;
+
+ preempt_disable();
switch (val) {
case DIE_INT3:
if (kprobe_handler(args->regs))
- return NOTIFY_STOP;
+ ret = NOTIFY_STOP;
break;
case DIE_DEBUG:
if (post_kprobe_handler(args->regs))
- return NOTIFY_STOP;
+ ret = NOTIFY_STOP;
break;
case DIE_GPF:
- if (kprobe_running() &&
- kprobe_fault_handler(args->regs, args->trapnr))
- return NOTIFY_STOP;
- break;
case DIE_PAGE_FAULT:
if (kprobe_running() &&
kprobe_fault_handler(args->regs, args->trapnr))
- return NOTIFY_STOP;
+ ret = NOTIFY_STOP;
break;
default:
break;
}
- return NOTIFY_DONE;
+ preempt_enable();
+ return ret;
}
int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
@@ -498,7 +500,6 @@ int __kprobes setjmp_pre_handler(struct
void __kprobes jprobe_return(void)
{
- preempt_enable_no_resched();
asm volatile (" xchgl %%ebx,%%esp \n"
" int3 \n"
" .globl jprobe_return_end \n"