commit 9caebec7b8093574fca5a334a1939530872d75e3
author Christoph Hellwig <hch@lst.de> Sat May 12 17:56:11 2007 +0200
committer Haavard Skinnemoen <hskinnemoen@atmel.com> Sun May 13 17:07:46 2007 +0200
tree 344415b09f6c08dfc8741420f7410f4e6105b584
parent 5d1938c83ca826891a02badef7c9ea8ed57e01a2

[AVR32] optimize pagefault path

Avoid the costly notifier list in the pagefault path and call
the kprobes code directly.  The same change went into the 2.6.22
cycle for powerpc, 2s390 and sparc64 already.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>

arch/avr32/mm/fault.c

diff --git a/arch/avr32/mm/fault.c b/arch/avr32/mm/fault.c
index 88b00b1..e011f1c 100644
--- a/arch/avr32/mm/fault.c
+++ b/arch/avr32/mm/fault.c
@@ -12,41 +12,30 @@
 #include <linux/mm.h>
 #include <linux/module.h>
 #include <linux/pagemap.h>
-
 #include <linux/kdebug.h>
+#include <linux/kprobes.h>
+
 #include <asm/mmu_context.h>
 #include <asm/sysreg.h>
 #include <asm/tlb.h>
 #include <asm/uaccess.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)
+static inline int notify_page_fault(struct pt_regs *regs, int trap)
 {
-	return atomic_notifier_chain_register(&notify_page_fault_chain, nb);
-}
+	int ret = 0;
 
-int unregister_page_fault_notifier(struct notifier_block *nb)
-{
-	return atomic_notifier_chain_unregister(&notify_page_fault_chain, nb);
-}
+	if (!user_mode(regs)) {
+		if (kprobe_running() && kprobe_fault_handler(regs, trap))
+			ret = 1;
+	}
 
-static inline int notify_page_fault(enum die_val val, struct pt_regs *regs,
-				    int trap, int sig)
-{
-	struct die_args args = {
-		.regs = regs,
-		.trapnr = trap,
-	};
-	return atomic_notifier_call_chain(&notify_page_fault_chain, val, &args);
+	return ret;
 }
 #else
-static inline int notify_page_fault(enum die_val val, struct pt_regs *regs,
-				    int trap, int sig)
+static inline int notify_page_fault(struct pt_regs *regs, int trap)
 {
-	return NOTIFY_DONE;
+	return 0;
 }
 #endif
 
@@ -76,8 +65,7 @@
 	long signr;
 	int code;
 
-	if (notify_page_fault(DIE_PAGE_FAULT, regs,
-			      ecr, SIGSEGV) == NOTIFY_STOP)
+	if (notify_page_fault(regs, ecr))
 		return;
 
 	address = sysreg_read(TLBEAR);