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Commit 59e87cdc authored by Masami Hiramatsu's avatar Masami Hiramatsu Committed by Ingo Molnar
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x86: move deeply indented code to reenter_kprobe 



Move some deeply indented code related to re-entrance processing
from kprobe_handler() to reenter_kprobe().

Signed-off-by: default avatarMasami Hiramatsu <mhiramat@redhat.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 40102d4a

arch/x86/kernel/kprobes.c

+23 −23
Original line number Diff line number Diff line
@@ -432,14 +432,32 @@ void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri, 
 * within the handler. We save the original kprobes variables and just single

 * step on the instruction of the new probe without calling any user handlers.

 */

static void __kprobes reenter_kprobe(struct kprobe *p, struct pt_regs *regs,

static int __kprobes reenter_kprobe(struct kprobe *p, struct pt_regs *regs,

				    struct kprobe_ctlblk *kcb)

{

	if (kcb->kprobe_status == KPROBE_HIT_SS &&

	    *p->ainsn.insn == BREAKPOINT_INSTRUCTION) {

		regs->flags &= ~X86_EFLAGS_TF;

		regs->flags |= kcb->kprobe_saved_flags;

		return 0;

#ifdef CONFIG_X86_64

	} else if (kcb->kprobe_status == KPROBE_HIT_SSDONE) {

		/* TODO: Provide re-entrancy from post_kprobes_handler() and

		 * avoid exception stack corruption while single-stepping on

		 * the instruction of the new probe.

		 */

		arch_disarm_kprobe(p);

		regs->ip = (unsigned long)p->addr;

		reset_current_kprobe();

		return 1;

#endif

	}

	save_previous_kprobe(kcb);

	set_current_kprobe(p, regs, kcb);

	kprobes_inc_nmissed_count(p);

	prepare_singlestep(p, regs);

	kcb->kprobe_status = KPROBE_REENTER;

	return 1;

}



/*
@@ -466,26 +484,8 @@ static int __kprobes kprobe_handler(struct pt_regs *regs) 
	if (kprobe_running()) {

		p = get_kprobe(addr);

		if (p) {

			if (kcb->kprobe_status == KPROBE_HIT_SS &&

				*p->ainsn.insn == BREAKPOINT_INSTRUCTION) {

				regs->flags &= ~X86_EFLAGS_TF;

				regs->flags |= kcb->kprobe_saved_flags;

				goto no_kprobe;

#ifdef CONFIG_X86_64

			} else if (kcb->kprobe_status == KPROBE_HIT_SSDONE) {

				/* TODO: Provide re-entrancy from

				 * post_kprobes_handler() and avoid exception

				 * stack corruption while single-stepping on

				 * the instruction of the new probe.

				 */

				arch_disarm_kprobe(p);

				regs->ip = (unsigned long)p->addr;

				reset_current_kprobe();

				ret = 1;

				goto no_kprobe;

#endif

			}

			reenter_kprobe(p, regs, kcb);

			ret = reenter_kprobe(p, regs, kcb);

			if (kcb->kprobe_status == KPROBE_REENTER)

				return 1;

		} else {

			if (*addr != BREAKPOINT_INSTRUCTION) {