[RFC PATCH 1/5][RESEND] livedump: Add notifier-call-chain intodo_page_fault

From: YOSHIDA Masanori
Date: Tue Dec 27 2011 - 04:43:23 EST

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@xxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: x86@xxxxxxxxxx
Cc: Andy Lutomirski <luto@xxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Cc: Marcelo Tosatti <mtosatti@xxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
Cc: linux-kernel@xxxxxxxxxxxxxxx

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);

+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;

* 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) &
+ return;
* Detect and handle instructions that would cause a page fault for
* both a tracked kernel page and a userspace page.

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/