Commit ae9a5b85 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 ia64



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 <anil.s.keshavamurthy@intel.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent b71b5b65
......@@ -19,6 +19,40 @@
extern void die (char *, struct pt_regs *, long);
#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)
{
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);
}
#else
static inline int notify_page_fault(enum die_val val, const char *str,
struct pt_regs *regs, long err, int trap, int sig)
{
return NOTIFY_DONE;
}
#endif
/*
* Return TRUE if ADDRESS points at a page in the kernel's mapped segment
* (inside region 5, on ia64) and that page is present.
......@@ -84,7 +118,7 @@ ia64_do_page_fault (unsigned long address, unsigned long isr, struct pt_regs *re
/*
* This is to handle the kprobes on user space access instructions
*/
if (notify_die(DIE_PAGE_FAULT, "page fault", regs, code, TRAP_BRKPT,
if (notify_page_fault(DIE_PAGE_FAULT, "page fault", regs, code, TRAP_BRKPT,
SIGSEGV) == NOTIFY_STOP)
return;
......
......@@ -40,6 +40,8 @@ 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 ia64die_chain;
enum die_val {
......
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