From d217d5450f11d8c907c0458d175b0dc999b4d06d Mon Sep 17 00:00:00 2001 From: Ananth N Mavinakayanahalli Date: Mon, 7 Nov 2005 01:00:14 -0800 Subject: [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 Signed-off-by: Anil S Keshavamurthy Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/sparc64/kernel/kprobes.c | 21 +++++++++++++-------- 1 file changed, 13 insertions(+), 8 deletions(-) (limited to 'arch/sparc64') diff --git a/arch/sparc64/kernel/kprobes.c b/arch/sparc64/kernel/kprobes.c index 58a815e9037..96bd09b098f 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; -- cgit v1.2.3-70-g09d2