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[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>
This commit is contained in:
Christoph Hellwig 2007-04-30 11:56:46 +01:00 committed by Paul Mackerras
parent eb609e52d1
commit 9f90b997de
4 changed files with 30 additions and 38 deletions
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10
arch/powerpc/kernel/kprobes.c
View File

@ -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;
}

40
arch/powerpc/mm/fault.c
View File

@ -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)
static inline int notify_page_fault(struct pt_regs *regs)
{
return atomic_notifier_chain_register(&notify_page_fault_chain, nb);
}
int ret = 0;
int unregister_page_fault_notifier(struct notifier_block *nb)
{
return atomic_notifier_chain_unregister(&notify_page_fault_chain, nb);
}
/* 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) {

17
include/asm-powerpc/kdebug.h
View File

@ -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)

1
include/asm-powerpc/kprobes.h
View File

@ -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 */