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author | Harvey Harrison <harvey.harrison@gmail.com> | 2008-01-30 12:32:19 (GMT) |
---|---|---|
committer | Ingo Molnar <mingo@elte.hu> | 2008-01-30 12:32:19 (GMT) |
commit | b97601563704751162b122c652d7f390b8f480d2 (patch) | |
tree | 81b0e2a22fb19ddb27bcb3c0bba769feafdc26e4 | |
parent | 33cb52438341d6e2d7e06e3b64ed776bc54a2ca4 (diff) | |
download | linux-fsl-qoriq-b97601563704751162b122c652d7f390b8f480d2.tar.xz |
x86: kprobes change kprobe_handler flow
Make the control flow of kprobe_handler more obvious.
Collapse the separate if blocks/gotos with if/else blocks
this unifies the duplication of the check for a breakpoint
instruction race with another cpu.
Create two jump targets:
preempt_out: re-enables preemption before returning ret
out: only returns ret
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
-rw-r--r-- | arch/x86/kernel/kprobes.c | 60 |
1 files changed, 28 insertions, 32 deletions
diff --git a/arch/x86/kernel/kprobes.c b/arch/x86/kernel/kprobes.c index 80bcb76..a72e02b 100644 --- a/arch/x86/kernel/kprobes.c +++ b/arch/x86/kernel/kprobes.c @@ -494,32 +494,28 @@ static int __kprobes kprobe_handler(struct pt_regs *regs) preempt_disable(); kcb = get_kprobe_ctlblk(); - /* Check we're not actually recursing */ - if (kprobe_running()) { - p = get_kprobe(addr); - if (p) { + p = get_kprobe(addr); + if (p) { + /* Check we're not actually recursing */ + if (kprobe_running()) { ret = reenter_kprobe(p, regs, kcb); if (kcb->kprobe_status == KPROBE_REENTER) - return 1; + { + ret = 1; + goto out; + } + goto preempt_out; } else { - if (*addr != BREAKPOINT_INSTRUCTION) { - /* The breakpoint instruction was removed by - * another cpu right after we hit, no further - * handling of this interrupt is appropriate - */ - regs->ip = (unsigned long)addr; + set_current_kprobe(p, regs, kcb); + kcb->kprobe_status = KPROBE_HIT_ACTIVE; + if (p->pre_handler && p->pre_handler(p, regs)) + { + /* handler set things up, skip ss setup */ ret = 1; - goto no_kprobe; + goto out; } - p = __get_cpu_var(current_kprobe); - if (p->break_handler && p->break_handler(p, regs)) - goto ss_probe; } - goto no_kprobe; - } - - p = get_kprobe(addr); - if (!p) { + } else { if (*addr != BREAKPOINT_INSTRUCTION) { /* * The breakpoint instruction was removed right @@ -532,34 +528,34 @@ static int __kprobes kprobe_handler(struct pt_regs *regs) */ regs->ip = (unsigned long)addr; ret = 1; + goto preempt_out; + } + if (kprobe_running()) { + p = __get_cpu_var(current_kprobe); + if (p->break_handler && p->break_handler(p, regs)) + goto ss_probe; } /* Not one of ours: let kernel handle it */ - goto no_kprobe; + goto preempt_out; } - set_current_kprobe(p, regs, kcb); - kcb->kprobe_status = KPROBE_HIT_ACTIVE; - - if (p->pre_handler && p->pre_handler(p, regs)) - /* handler has already set things up, so skip ss setup */ - return 1; - ss_probe: + ret = 1; #if !defined(CONFIG_PREEMPT) || defined(CONFIG_PM) if (p->ainsn.boostable == 1 && !p->post_handler) { /* Boost up -- we can execute copied instructions directly */ reset_current_kprobe(); regs->ip = (unsigned long)p->ainsn.insn; - preempt_enable_no_resched(); - return 1; + goto preempt_out; } #endif prepare_singlestep(p, regs); kcb->kprobe_status = KPROBE_HIT_SS; - return 1; + goto out; -no_kprobe: +preempt_out: preempt_enable_no_resched(); +out: return ret; } |