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authorAnanth N Mavinakayanahalli <ananth@in.ibm.com>2005-11-07 01:00:14 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2005-11-07 07:53:46 -0800
commitd217d5450f11d8c907c0458d175b0dc999b4d06d (patch)
treeebd68eb9e0b632049d22240a3589887ca27077a5 /arch/sparc64/kernel/kprobes.c
parent991a51d83a3d9bebfafdd1e692cf310899d60791 (diff)
[PATCH] Kprobes: preempt_disable/enable() simplification
Reorganize the preempt_disable/enable calls to eliminate the extra preempt depth. Changes based on Paul McKenney's review suggestions for the kprobes RCU changeset. Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Signed-off-by: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch/sparc64/kernel/kprobes.c')
-rw-r--r--arch/sparc64/kernel/kprobes.c21
1 files changed, 13 insertions, 8 deletions
diff --git a/arch/sparc64/kernel/kprobes.c b/arch/sparc64/kernel/kprobes.c
index 58a815e90373..96bd09b098f4 100644
--- a/arch/sparc64/kernel/kprobes.c
+++ b/arch/sparc64/kernel/kprobes.c
@@ -113,7 +113,14 @@ static int __kprobes kprobe_handler(struct pt_regs *regs)
struct kprobe *p;
void *addr = (void *) regs->tpc;
int ret = 0;
- struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
+ struct kprobe_ctlblk *kcb;
+
+ /*
+ * We don't want to be preempted for the entire
+ * duration of kprobe processing
+ */
+ preempt_disable();
+ kcb = get_kprobe_ctlblk();
if (kprobe_running()) {
p = get_kprobe(addr);
@@ -159,11 +166,6 @@ static int __kprobes kprobe_handler(struct pt_regs *regs)
goto no_kprobe;
}
- /*
- * This preempt_disable() matches the preempt_enable_no_resched()
- * in post_kprobes_handler()
- */
- preempt_disable();
set_current_kprobe(p, regs, kcb);
kcb->kprobe_status = KPROBE_HIT_ACTIVE;
if (p->pre_handler && p->pre_handler(p, regs))
@@ -175,6 +177,7 @@ ss_probe:
return 1;
no_kprobe:
+ preempt_enable_no_resched();
return ret;
}
@@ -321,7 +324,6 @@ int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
struct die_args *args = (struct die_args *)data;
int ret = NOTIFY_DONE;
- rcu_read_lock();
switch (val) {
case DIE_DEBUG:
if (kprobe_handler(args->regs))
@@ -333,14 +335,16 @@ int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
break;
case DIE_GPF:
case DIE_PAGE_FAULT:
+ /* kprobe_running() needs smp_processor_id() */
+ preempt_disable();
if (kprobe_running() &&
kprobe_fault_handler(args->regs, args->trapnr))
ret = NOTIFY_STOP;
+ preempt_enable();
break;
default:
break;
}
- rcu_read_unlock();
return ret;
}
@@ -426,6 +430,7 @@ int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
&(kcb->jprobe_saved_stack),
sizeof(kcb->jprobe_saved_stack));
+ preempt_enable_no_resched();
return 1;
}
return 0;