[patch 9/9] Text Edit Lock - kprobes x86_64

[Mathieu Desnoyers]

Kprobes can use the text edit lock to insure mutual exclusion when editing the
code.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxx>
CC: Andi Kleen <andi@xxxxxxxxxxxxxx>
CC: prasanna@xxxxxxxxxx
CC: ananth@xxxxxxxxxx
CC: anil.s.keshavamurthy@xxxxxxxxx
CC: davem@xxxxxxxxxxxxx
---
 arch/x86_64/kernel/kprobes.c |    9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

Index: linux-2.6-lttng/arch/x86_64/kernel/kprobes.c
===================================================================
--- linux-2.6-lttng.orig/arch/x86_64/kernel/kprobes.c	2007-08-10 16:44:23.000000000 -0400
+++ linux-2.6-lttng/arch/x86_64/kernel/kprobes.c	2007-08-10 17:21:07.000000000 -0400
@@ -42,6 +42,7 @@
 #include <asm/pgtable.h>
 #include <asm/uaccess.h>
 #include <asm/alternative.h>
+#include <asm/cacheflush.h>
 
 void jprobe_return_end(void);
 static void __kprobes arch_copy_kprobe(struct kprobe *p);
@@ -209,12 +210,16 @@ static void __kprobes arch_copy_kprobe(s
 
 void __kprobes arch_arm_kprobe(struct kprobe *p)
 {
-	text_poke(p->addr, ((unsigned char []){BREAKPOINT_INSTRUCTION}), 1);
+	kernel_text_mark_rw((unsigned long) p->addr, sizeof(kprobe_opcode_t));
+	*p->addr = BREAKPOINT_INSTRUCTION;
+	kernel_text_unmark((unsigned long) p->addr, sizeof(kprobe_opcode_t));
 }
 
 void __kprobes arch_disarm_kprobe(struct kprobe *p)
 {
-	text_poke(p->addr, &p->opcode, 1);
+	kernel_text_mark_rw((unsigned long) p->addr, sizeof(kprobe_opcode_t));
+	*p->addr = p->opcode;
+	kernel_text_unmark((unsigned long) p->addr, sizeof(kprobe_opcode_t));
 }
 
 void __kprobes arch_remove_kprobe(struct kprobe *p)

-- 
Mathieu Desnoyers
Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F  BA06 3F25 A8FE 3BAE 9A68
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