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

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
......@@ -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);
......
......@@ -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);
......
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