Messages in this thread Patch in this message | | | From | YOSHIDA Masanori <> | Subject | [RFC PATCH 1/5][RESEND] livedump: Add notifier-call-chain into do_page_fault | Date | Fri, 23 Dec 2011 22:14:41 +0900 |
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This patch adds notifier-call-chain that is called in do_page_fault. This can be used to check whether page fault occurs for the normal reason, or it is caused by special write protection, for example Live Dump.
Signed-off-by: YOSHIDA Masanori <masanori.yoshida.tv@hitachi.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: x86@kernel.org Cc: Andy Lutomirski <luto@mit.edu> Cc: Rik van Riel <riel@redhat.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: linux-kernel@vger.kernel.org ---
arch/x86/include/asm/traps.h | 2 ++ arch/x86/mm/fault.c | 7 +++++++ 2 files changed, 9 insertions(+), 0 deletions(-)
diff --git a/arch/x86/include/asm/traps.h b/arch/x86/include/asm/traps.h index 0012d09..7bf6081 100644 --- a/arch/x86/include/asm/traps.h +++ b/arch/x86/include/asm/traps.h @@ -89,4 +89,6 @@ asmlinkage void smp_thermal_interrupt(void); asmlinkage void mce_threshold_interrupt(void); #endif +extern struct atomic_notifier_head page_fault_notifier_list; + #endif /* _ASM_X86_TRAPS_H */ diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index 5db0490..2f8e2a9 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -985,6 +985,8 @@ static int fault_in_kernel_space(unsigned long address) return address >= TASK_SIZE_MAX; } +ATOMIC_NOTIFIER_HEAD(page_fault_notifier_list); + /* * This routine handles page faults. It determines the address, * and the problem, and then passes it off to one of the appropriate @@ -1008,6 +1010,11 @@ do_page_fault(struct pt_regs *regs, unsigned long error_code) /* Get the faulting address: */ address = read_cr2(); + if (atomic_notifier_call_chain( + &page_fault_notifier_list, error_code, regs) & + NOTIFY_OK) + return; + /* * Detect and handle instructions that would cause a page fault for * both a tracked kernel page and a userspace page.
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