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Commit f72180cc authored by Naveen N. Rao's avatar Naveen N. Rao Committed by Michael Ellerman
Browse files

powerpc/kprobes: Do not disable interrupts for optprobes and kprobes_on_ftrace 



Per Documentation/kprobes.txt, we don't necessarily need to disable
interrupts before invoking the kprobe handlers. Masami submitted
similar changes for x86 via commit a19b2e3d ("kprobes/x86: Remove
IRQ disabling from ftrace-based/optimized kprobes"). Do the same for
powerpc.

Signed-off-by: default avatarNaveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Acked-by: default avatarMasami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent 8a2d71a3

arch/powerpc/kernel/kprobes-ftrace.c

+2 −8
Original line number Diff line number Diff line
@@ -75,11 +75,7 @@ void kprobe_ftrace_handler(unsigned long nip, unsigned long parent_nip, 
{

	struct kprobe *p;

	struct kprobe_ctlblk *kcb;

	unsigned long flags;



	/* Disable irq for emulating a breakpoint and avoiding preempt */

	local_irq_save(flags);

	hard_irq_disable();

	preempt_disable();



	p = get_kprobe((kprobe_opcode_t *)nip);
@@ -105,16 +101,14 @@ void kprobe_ftrace_handler(unsigned long nip, unsigned long parent_nip, 
		else {

			/*

			 * If pre_handler returns !0, it sets regs->nip and

			 * resets current kprobe. In this case, we still need

			 * to restore irq, but not preemption.

			 * resets current kprobe. In this case, we should not

			 * re-enable preemption.

			 */

			local_irq_restore(flags);

			return;

		}

	}

end:

	preempt_enable_no_resched();

	local_irq_restore(flags);

}

NOKPROBE_SYMBOL(kprobe_ftrace_handler);

arch/powerpc/kernel/optprobes.c

+0 −10
Original line number Diff line number Diff line
@@ -115,14 +115,10 @@ static unsigned long can_optimize(struct kprobe *p) 
static void optimized_callback(struct optimized_kprobe *op,

			       struct pt_regs *regs)

{

	unsigned long flags;



	/* This is possible if op is under delayed unoptimizing */

	if (kprobe_disabled(&op->kp))

		return;



	local_irq_save(flags);

	hard_irq_disable();

	preempt_disable();



	if (kprobe_running()) {
@@ -135,13 +131,7 @@ static void optimized_callback(struct optimized_kprobe *op, 
		__this_cpu_write(current_kprobe, NULL);

	}



	/*

	 * No need for an explicit __hard_irq_enable() here.

	 * local_irq_restore() will re-enable interrupts,

	 * if they were hard disabled.

	 */

	preempt_enable_no_resched();

	local_irq_restore(flags);

}

NOKPROBE_SYMBOL(optimized_callback);