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powerpc/kprobes: Don't call the ->break_handler() in powerpc kprobes code 

Don't call the ->break_handler() from the powerpc kprobes code,
because it was only used by jprobes which got removed.

This also removes skip_singlestep() and embeds it in the
caller, kprobe_ftrace_handler(), which simplifies regs->nip
operation around there.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-arch@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Link: https://lore.kernel.org/lkml/152942477127.15209.8982613703787878618.stgit@devbox
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Masami Hiramatsu 2018-06-20 01:12:51 +09:00 committed by Ingo Molnar
parent c9abd554aa
commit 6e5fd3a298
3 changed files with 23 additions and 64 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
arch/powerpc/include/asm/kprobes.h
View File

@ -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; }

46
arch/powerpc/kernel/kprobes-ftrace.c
View File

@ -25,35 +25,6 @@
#include <linux/preempt.h>
#include <linux/ftrace.h>
static nokprobe_inline
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)
* as if there is a nop
*/
regs->nip = (unsigned long)p->addr + MCOUNT_INSN_SIZE;
if (unlikely(p->post_handler)) {
kcb->kprobe_status = KPROBE_HIT_SSDONE;
p->post_handler(p, regs, 0);
}
__this_cpu_write(current_kprobe, NULL);
if (orig_nip)
regs->nip = orig_nip;
return 1;
}
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)
@ -71,8 +42,6 @@ void kprobe_ftrace_handler(unsigned long nip, unsigned long parent_nip,
if (kprobe_running()) {
kprobes_inc_nmissed_count(p);
} else {
unsigned long orig_nip = regs->nip;
/*
* On powerpc, NIP is *before* this instruction for the
* pre handler
@ -81,9 +50,18 @@ void kprobe_ftrace_handler(unsigned long nip, unsigned long parent_nip,
__this_cpu_write(current_kprobe, p);
kcb->kprobe_status = KPROBE_HIT_ACTIVE;
if (!p->pre_handler || !p->pre_handler(p, regs))
__skip_singlestep(p, regs, kcb, orig_nip);
else {
if (!p->pre_handler || !p->pre_handler(p, regs)) {
/*
* Emulate singlestep (and also recover regs->nip)
* as if there is a nop
*/
regs->nip += MCOUNT_INSN_SIZE;
if (unlikely(p->post_handler)) {
kcb->kprobe_status = KPROBE_HIT_SSDONE;
p->post_handler(p, regs, 0);
}
__this_cpu_write(current_kprobe, NULL);
} else {
/*
* If pre_handler returns !0, it sets regs->nip and
* resets current kprobe. In this case, we should not

31
arch/powerpc/kernel/kprobes.c
View File

@ -317,25 +317,17 @@ int kprobe_handler(struct pt_regs *regs)
}
prepare_singlestep(p, regs);
return 1;
} else {
if (*addr != BREAKPOINT_INSTRUCTION) {
/* If trap variant, then it belongs not to us */
kprobe_opcode_t cur_insn = *addr;
if (is_trap(cur_insn))
goto no_kprobe;
/* The breakpoint instruction was removed by
* another cpu right after we hit, no further
* handling of this interrupt is appropriate
*/
ret = 1;
} else if (*addr != BREAKPOINT_INSTRUCTION) {
/* If trap variant, then it belongs not to us */
kprobe_opcode_t cur_insn = *addr;
if (is_trap(cur_insn))
goto no_kprobe;
}
p = __this_cpu_read(current_kprobe);
if (p->break_handler && p->break_handler(p, regs)) {
if (!skip_singlestep(p, regs, kcb))
goto ss_probe;
ret = 1;
}
/* The breakpoint instruction was removed by
* another cpu right after we hit, no further
* handling of this interrupt is appropriate
*/
ret = 1;
}
goto no_kprobe;
}
@ -350,7 +342,7 @@ int kprobe_handler(struct pt_regs *regs)
*/
kprobe_opcode_t cur_insn = *addr;
if (is_trap(cur_insn))
goto no_kprobe;
goto no_kprobe;
/*
* The breakpoint instruction was removed right
* after we hit it. Another cpu has removed
@ -370,7 +362,6 @@ int kprobe_handler(struct pt_regs *regs)
/* handler has already set things up, so skip ss setup */
return 1;
ss_probe:
if (p->ainsn.boostable >= 0) {
ret = try_to_emulate(p, regs);