Commit 4f9e87c0 authored by Anil S Keshavamurthy's avatar Anil S Keshavamurthy Committed by Linus Torvalds
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[PATCH] Notify page fault call chain for powerpc

Overloading of page fault notification with the notify_die() has performance
issues(since the only interested components for page fault is kprobes and/or
kdb) and hence this patch introduces the new notifier call chain exclusively
for page fault notifications their by avoiding notifying unnecessary
components in the do_page_fault() code path.
Signed-off-by: default avatarAnil S Keshavamurthy <>
Signed-off-by: default avatarAndrew Morton <>
Signed-off-by: default avatarLinus Torvalds <>
parent ae9a5b85
......@@ -40,6 +40,40 @@
#include <asm/kdebug.h>
#include <asm/siginfo.h>
/* 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)
return atomic_notifier_chain_unregister(&notify_page_fault_chain, nb);
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);
static inline int notify_page_fault(enum die_val val, const char *str,
struct pt_regs *regs, long err, int trap, int sig)
* Check whether the instruction at regs->nip is a store using
* an update addressing form which will update r1.
......@@ -142,7 +176,7 @@ 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_die(DIE_PAGE_FAULT, "page_fault", regs, error_code,
if (notify_page_fault(DIE_PAGE_FAULT, "page_fault", regs, error_code,
return 0;
......@@ -18,6 +18,8 @@ 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 *);
extern struct atomic_notifier_head powerpc_die_chain;
/* Grossly misnamed. */
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