... rather than through notify_die(), to reduce path taken for handling
kprobes. Similar to commit 6f6343f53d13 ("kprobes/x86: Call exception
handlers directly from do_int3/do_debug").
While at it, rename post_kprobe_handler() to kprobe_post_handler() for
more uniform naming.
Reported-by: Masami Hiramatsu <mhira...@kernel.org>
Signed-off-by: Naveen N. Rao <naveen.n....@linux.vnet.ibm.com>
---
arch/powerpc/include/asm/kprobes.h | 2 ++
arch/powerpc/kernel/kprobes.c | 29 +++++++----------------------
arch/powerpc/kernel/traps.c | 20 ++++++++++++++++++++
3 files changed, 29 insertions(+), 22 deletions(-)
diff --git a/arch/powerpc/include/asm/kprobes.h
b/arch/powerpc/include/asm/kprobes.h
index 2c9759bd..47c60d0 100644
--- a/arch/powerpc/include/asm/kprobes.h
+++ b/arch/powerpc/include/asm/kprobes.h
@@ -126,6 +126,8 @@ struct kprobe_ctlblk {
extern int kprobe_exceptions_notify(struct notifier_block *self,
unsigned long val, void *data);
+extern int kprobe_handler(struct pt_regs *regs);
+extern int kprobe_post_handler(struct pt_regs *regs);
extern int kprobe_fault_handler(struct pt_regs *regs, int trapnr);
#endif /* __KERNEL__ */
#endif /* _ASM_POWERPC_KPROBES_H */
diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c
index 9479d8e..ad108b8 100644
--- a/arch/powerpc/kernel/kprobes.c
+++ b/arch/powerpc/kernel/kprobes.c
@@ -140,13 +140,16 @@ void __kprobes arch_prepare_kretprobe(struct
kretprobe_instance *ri,
regs->link = (unsigned long)kretprobe_trampoline;
}
-static int __kprobes kprobe_handler(struct pt_regs *regs)
+int __kprobes kprobe_handler(struct pt_regs *regs)
{
struct kprobe *p;
int ret = 0;
unsigned int *addr = (unsigned int *)regs->nip;
struct kprobe_ctlblk *kcb;
+ if (user_mode(regs))
+ return 0;
+
/*
* We don't want to be preempted for the entire
* duration of kprobe processing
@@ -359,12 +362,12 @@ static int __kprobes trampoline_probe_handler(struct
kprobe *p,
* single-stepped a copy of the instruction. The address of this
* copy is p->ainsn.insn.
*/
-static int __kprobes post_kprobe_handler(struct pt_regs *regs)
+int __kprobes kprobe_post_handler(struct pt_regs *regs)
{
struct kprobe *cur = kprobe_running();
struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
- if (!cur)
+ if (!cur || user_mode(regs))
return 0;
/* make sure we got here for instruction we have a kprobe on */
@@ -470,25 +473,7 @@ int __kprobes kprobe_fault_handler(struct pt_regs *regs,
int trapnr)
int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
unsigned long val, void *data)
{
- struct die_args *args = (struct die_args *)data;
- int ret = NOTIFY_DONE;
-
- if (args->regs && user_mode(args->regs))
- return ret;
-
- switch (val) {
- case DIE_BPT:
- if (kprobe_handler(args->regs))
- ret = NOTIFY_STOP;
- break;
- case DIE_SSTEP:
- if (post_kprobe_handler(args->regs))
- ret = NOTIFY_STOP;
- break;
- default:
- break;
- }
- return ret;
+ return NOTIFY_DONE;
}
unsigned long arch_deref_entry_point(void *entry)
diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index 91d278c..dbcdf48 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c
@@ -824,6 +824,11 @@ void single_step_exception(struct pt_regs *regs)
clear_single_step(regs);
+#ifdef CONFIG_KPROBES
+ if (kprobe_post_handler(regs))
+ return;
+#endif
+
if (notify_die(DIE_SSTEP, "single_step", regs, 5,
5, SIGTRAP) == NOTIFY_STOP)
goto bail;
@@ -1177,6 +1182,11 @@ void program_check_exception(struct pt_regs *regs)
if (debugger_bpt(regs))
goto bail;
+#ifdef CONFIG_KPROBES
+ if (kprobe_handler(regs))
+ goto bail;
+#endif
+
/* trap exception */
if (notify_die(DIE_BPT, "breakpoint", regs, 5, 5, SIGTRAP)
== NOTIFY_STOP)
@@ -1745,6 +1755,11 @@ void DebugException(struct pt_regs *regs, unsigned long
debug_status)
return;
}
+#ifdef CONFIG_KPROBES
+ if (kprobe_post_handler(regs))
+ return;
+#endif
+
if (notify_die(DIE_SSTEP, "block_step", regs, 5,
5, SIGTRAP) == NOTIFY_STOP) {
return;
@@ -1759,6 +1774,11 @@ void DebugException(struct pt_regs *regs, unsigned long
debug_status)
/* Clear the instruction completion event */
mtspr(SPRN_DBSR, DBSR_IC);
+#ifdef CONFIG_KPROBES
+ if (kprobe_post_handler(regs))
+ return;
+#endif
+
if (notify_die(DIE_SSTEP, "single_step", regs, 5,
5, SIGTRAP) == NOTIFY_STOP) {
return;
--
2.10.2
