Re: [RFC PATCH -tip v5 18/27] powerpc/kprobes: Don't call the ->break_handler() in arm kprobes code
From: Naveen N. Rao <hidden>
Date: 2018-06-07 11:37:15
Also in:
linux-arch, lkml
Masami Hiramatsu wrote:
Don't call the ->break_handler() from the arm kprobes code,
^^^ powerpc
because it was only used by jprobes which got removed. =20 This also makes skip_singlestep() a static function since only ftrace-kprobe.c is using this function. =20 Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <redacted> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: "Naveen N. Rao" <redacted> Cc: linuxppc-dev@lists.ozlabs.org --- arch/powerpc/include/asm/kprobes.h | 10 ---------- arch/powerpc/kernel/kprobes-ftrace.c | 16 +++------------- arch/powerpc/kernel/kprobes.c | 31 +++++++++++-----------------=
---
3 files changed, 14 insertions(+), 43 deletions(-)
With 2 small comments... Acked-by: Naveen N. Rao <redacted> - Naveen
quoted hunk ↗ jump to hunk
=20diff --git a/arch/powerpc/include/asm/kprobes.h b/arch/powerpc/include/as=
m/kprobes.h
quoted hunk ↗ jump to hunk
index 674036db558b..785c464b6588 100644--- a/arch/powerpc/include/asm/kprobes.h +++ b/arch/powerpc/include/asm/kprobes.h@@ -102,16 +102,6 @@ extern int kprobe_exceptions_notify(struct notifier_=
block *self,
extern int kprobe_fault_handler(struct pt_regs *regs, int trapnr); extern int kprobe_handler(struct pt_regs *regs); extern int kprobe_post_handler(struct pt_regs *regs); -#ifdef CONFIG_KPROBES_ON_FTRACE -extern int skip_singlestep(struct kprobe *p, struct pt_regs *regs, - struct kprobe_ctlblk *kcb); -#else -static inline int skip_singlestep(struct kprobe *p, struct pt_regs *regs=
,
- struct kprobe_ctlblk *kcb)
-{
- return 0;
-}
-#endif
#else
static inline int kprobe_handler(struct pt_regs *regs) { return 0; }
static inline int kprobe_post_handler(struct pt_regs *regs) { return 0; =}
quoted hunk ↗ jump to hunk
diff --git a/arch/powerpc/kernel/kprobes-ftrace.c b/arch/powerpc/kernel/k=
probes-ftrace.c
quoted hunk ↗ jump to hunk
index 1b316331c2d9..3869b0e5d5c7 100644--- a/arch/powerpc/kernel/kprobes-ftrace.c +++ b/arch/powerpc/kernel/kprobes-ftrace.c@@ -26,8 +26,8 @@ #include <linux/ftrace.h>=20 static nokprobe_inline -int __skip_singlestep(struct kprobe *p, struct pt_regs *regs, - struct kprobe_ctlblk *kcb, unsigned long orig_nip) +int skip_singlestep(struct kprobe *p, struct pt_regs *regs, + struct kprobe_ctlblk *kcb, unsigned long orig_nip) { /* * Emulate singlestep (and also recover regs->nip)@@ -44,16 +44,6 @@ int __skip_singlestep(struct kprobe *p, struct pt_regs=
*regs,
quoted hunk ↗ jump to hunk
return 1; } =20 -int skip_singlestep(struct kprobe *p, struct pt_regs *regs, - struct kprobe_ctlblk *kcb) -{ - if (kprobe_ftrace(p)) - return __skip_singlestep(p, regs, kcb, 0); - else - return 0; -} -NOKPROBE_SYMBOL(skip_singlestep); - /* Ftrace callback handler for kprobes */ void kprobe_ftrace_handler(unsigned long nip, unsigned long parent_nip, struct ftrace_ops *ops, struct pt_regs *regs)@@ -82,7 +72,7 @@ void kprobe_ftrace_handler(unsigned long nip, unsigned =
long parent_nip,
__this_cpu_write(current_kprobe, p); kcb->kprobe_status =3D KPROBE_HIT_ACTIVE; if (!p->pre_handler || !p->pre_handler(p, regs)) - __skip_singlestep(p, regs, kcb, orig_nip); + skip_singlestep(p, regs, kcb, orig_nip);
We can probably get rid of skip_singlestep() completely along with=20 orig_nip since instructions are always 4 bytes on powerpc. So, the=20 changes we do to nip should help to recover the value automatically. - Naveen =