Commit d98f8f05 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 sparc64



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 4f9e87c0
...@@ -31,6 +31,40 @@ ...@@ -31,6 +31,40 @@
#include <asm/kdebug.h> #include <asm/kdebug.h>
#include <asm/mmu_context.h> #include <asm/mmu_context.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)
{
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
/* /*
* To debug kernel to catch accesses to certain virtual/physical addresses. * To debug kernel to catch accesses to certain virtual/physical addresses.
* Mode = 0 selects physical watchpoints, mode = 1 selects virtual watchpoints. * Mode = 0 selects physical watchpoints, mode = 1 selects virtual watchpoints.
...@@ -263,7 +297,7 @@ asmlinkage void __kprobes do_sparc64_fault(struct pt_regs *regs) ...@@ -263,7 +297,7 @@ asmlinkage void __kprobes do_sparc64_fault(struct pt_regs *regs)
fault_code = get_thread_fault_code(); fault_code = get_thread_fault_code();
if (notify_die(DIE_PAGE_FAULT, "page_fault", regs, if (notify_page_fault(DIE_PAGE_FAULT, "page_fault", regs,
fault_code, 0, SIGSEGV) == NOTIFY_STOP) fault_code, 0, SIGSEGV) == NOTIFY_STOP)
return; return;
......
...@@ -17,6 +17,8 @@ struct die_args { ...@@ -17,6 +17,8 @@ struct die_args {
extern int register_die_notifier(struct notifier_block *); extern int register_die_notifier(struct notifier_block *);
extern int unregister_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 sparc64die_chain; extern struct atomic_notifier_head sparc64die_chain;
extern void bad_trap(struct pt_regs *, long); extern void bad_trap(struct pt_regs *, long);
......
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