| Message ID | 60fe689be1e3251c001a6d4303fd808a3a760711.1508776485.git.naveen.n.rao@linux.vnet.ibm.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | f72180cc93a2c64d4efe0129fa2396ad78be80e3 |
| Headers | show |
| Series | [1/4] powerpc/kprobes: Disable preemption before invoking probe handler for optprobes | expand |
On Mon, 23 Oct 2017 22:07:39 +0530 "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com> wrote: > 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 a19b2e3d783964 ("kprobes/x86: Remove > IRQ disabling from ftrace-based/optimized kprobes"). Do the same for > powerpc. Yes, and this requires to make preempt disable :) Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Thank you! > > Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> > --- > arch/powerpc/kernel/kprobes-ftrace.c | 10 ++-------- > arch/powerpc/kernel/optprobes.c | 10 ---------- > 2 files changed, 2 insertions(+), 18 deletions(-) > > diff --git a/arch/powerpc/kernel/kprobes-ftrace.c b/arch/powerpc/kernel/kprobes-ftrace.c > index 4b1f34f685b1..7a1f99f1b47f 100644 > --- a/arch/powerpc/kernel/kprobes-ftrace.c > +++ b/arch/powerpc/kernel/kprobes-ftrace.c > @@ -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); > > diff --git a/arch/powerpc/kernel/optprobes.c b/arch/powerpc/kernel/optprobes.c > index 60ba7f1370a8..8237884ca389 100644 > --- a/arch/powerpc/kernel/optprobes.c > +++ b/arch/powerpc/kernel/optprobes.c > @@ -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); > > -- > 2.14.2 >
diff --git a/arch/powerpc/kernel/kprobes-ftrace.c b/arch/powerpc/kernel/kprobes-ftrace.c index 4b1f34f685b1..7a1f99f1b47f 100644 --- a/arch/powerpc/kernel/kprobes-ftrace.c +++ b/arch/powerpc/kernel/kprobes-ftrace.c @@ -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); diff --git a/arch/powerpc/kernel/optprobes.c b/arch/powerpc/kernel/optprobes.c index 60ba7f1370a8..8237884ca389 100644 --- a/arch/powerpc/kernel/optprobes.c +++ b/arch/powerpc/kernel/optprobes.c @@ -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);
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 a19b2e3d783964 ("kprobes/x86: Remove IRQ disabling from ftrace-based/optimized kprobes"). Do the same for powerpc. Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> --- arch/powerpc/kernel/kprobes-ftrace.c | 10 ++-------- arch/powerpc/kernel/optprobes.c | 10 ---------- 2 files changed, 2 insertions(+), 18 deletions(-)