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authorChristoph Hellwig <hch@infradead.org>2007-04-30 11:56:46 +0100
committerPaul Mackerras <paulus@samba.org>2007-05-02 20:57:39 +1000
commit9f90b997de4efd5404a8c52f89c400f0f4e2d216 (patch)
tree7dd6adc27b196e672fedd464a42700e336cd210a
parenteb609e52d188775da738a1ffd1e982e6212c77d7 (diff)
[POWERPC] Minor fault path optimization
Call the kprobes pagefault handler directly instead of going through the complex notifier chain. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Paul Mackerras <paulus@samba.org>
-rw-r--r--arch/powerpc/kernel/kprobes.c10
-rw-r--r--arch/powerpc/mm/fault.c42
-rw-r--r--include/asm-powerpc/kdebug.h17
-rw-r--r--include/asm-powerpc/kprobes.h1
4 files changed, 31 insertions, 39 deletions
diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c
index ef647e7a9dc3..c27f41870c8f 100644
--- a/arch/powerpc/kernel/kprobes.c
+++ b/arch/powerpc/kernel/kprobes.c
@@ -410,7 +410,7 @@ out:
return 1;
}
-static int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
+int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
{
struct kprobe *cur = kprobe_running();
struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
@@ -495,14 +495,6 @@ int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
if (post_kprobe_handler(args->regs))
ret = NOTIFY_STOP;
break;
- case DIE_PAGE_FAULT:
- /* kprobe_running() needs smp_processor_id() */
- preempt_disable();
- if (kprobe_running() &&
- kprobe_fault_handler(args->regs, args->trapnr))
- ret = NOTIFY_STOP;
- preempt_enable();
- break;
default:
break;
}
diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c
index 03aeb3a46077..a0f88026e464 100644
--- a/arch/powerpc/mm/fault.c
+++ b/arch/powerpc/mm/fault.c
@@ -39,37 +39,26 @@
#include <asm/kdebug.h>
#include <asm/siginfo.h>
-#ifdef CONFIG_KPROBES
-ATOMIC_NOTIFIER_HEAD(notify_page_fault_chain);
-/* Hook to register for page fault notifications */
-int register_page_fault_notifier(struct notifier_block *nb)
-{
- return atomic_notifier_chain_register(&notify_page_fault_chain, nb);
-}
-
-int unregister_page_fault_notifier(struct notifier_block *nb)
+#ifdef CONFIG_KPROBES
+static inline int notify_page_fault(struct pt_regs *regs)
{
- return atomic_notifier_chain_unregister(&notify_page_fault_chain, nb);
-}
+ int ret = 0;
+
+ /* kprobe_running() needs smp_processor_id() */
+ if (!user_mode(regs)) {
+ preempt_disable();
+ if (kprobe_running() && kprobe_fault_handler(regs, 11))
+ ret = 1;
+ preempt_enable();
+ }
-static inline int notify_page_fault(enum die_val val, const char *str,
- struct pt_regs *regs, long err, int trap, int sig)
-{
- struct die_args args = {
- .regs = regs,
- .str = str,
- .err = err,
- .trapnr = trap,
- .signr = sig
- };
- return atomic_notifier_call_chain(&notify_page_fault_chain, val, &args);
+ return ret;
}
#else
-static inline int notify_page_fault(enum die_val val, const char *str,
- struct pt_regs *regs, long err, int trap, int sig)
+static inline int notify_page_fault(struct pt_regs *regs)
{
- return NOTIFY_DONE;
+ return 0;
}
#endif
@@ -175,8 +164,7 @@ int __kprobes do_page_fault(struct pt_regs *regs, unsigned long address,
is_write = error_code & ESR_DST;
#endif /* CONFIG_4xx || CONFIG_BOOKE */
- if (notify_page_fault(DIE_PAGE_FAULT, "page_fault", regs, error_code,
- 11, SIGSEGV) == NOTIFY_STOP)
+ if (notify_page_fault(regs))
return 0;
if (trap == 0x300) {
diff --git a/include/asm-powerpc/kdebug.h b/include/asm-powerpc/kdebug.h
index 532bfee934f4..df996b933def 100644
--- a/include/asm-powerpc/kdebug.h
+++ b/include/asm-powerpc/kdebug.h
@@ -18,8 +18,20 @@ struct die_args {
extern int register_die_notifier(struct notifier_block *);
extern int unregister_die_notifier(struct notifier_block *);
-extern int register_page_fault_notifier(struct notifier_block *);
-extern int unregister_page_fault_notifier(struct notifier_block *);
+
+/*
+ * These are only here because kprobes.c wants them to implement a
+ * blatant layering violation. Will hopefully go away soon once all
+ * architectures are updated.
+ */
+static inline int register_page_fault_notifier(struct notifier_block *nb)
+{
+ return 0;
+}
+static inline int unregister_page_fault_notifier(struct notifier_block *nb)
+{
+ return 0;
+}
extern struct atomic_notifier_head powerpc_die_chain;
/* Grossly misnamed. */
@@ -29,7 +41,6 @@ enum die_val {
DIE_DABR_MATCH,
DIE_BPT,
DIE_SSTEP,
- DIE_PAGE_FAULT,
};
static inline int notify_die(enum die_val val,char *str,struct pt_regs *regs,long err,int trap, int sig)
diff --git a/include/asm-powerpc/kprobes.h b/include/asm-powerpc/kprobes.h
index fc713e595982..b0e40ff32ee0 100644
--- a/include/asm-powerpc/kprobes.h
+++ b/include/asm-powerpc/kprobes.h
@@ -116,5 +116,6 @@ struct kprobe_ctlblk {
extern int kprobe_exceptions_notify(struct notifier_block *self,
unsigned long val, void *data);
+extern int kprobe_fault_handler(struct pt_regs *regs, int trapnr);
#endif /* __KERNEL__ */
#endif /* _ASM_POWERPC_KPROBES_H */