[patch 3/3] Text Edit Lock - kprobes i386

[Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>]

Kprobes can use the text edit lock to insure mutual exclusion when edition the
code and make sure the pages are writable.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
---
 arch/i386/kernel/kprobes.c |    4 ++++
 1 file changed, 4 insertions(+)

Index: linux-2.6-lttng/arch/i386/kernel/kprobes.c
===================================================================
--- linux-2.6-lttng.orig/arch/i386/kernel/kprobes.c	2007-06-18 17:41:27.000000000 -0400
+++ linux-2.6-lttng/arch/i386/kernel/kprobes.c	2007-06-18 17:41:31.000000000 -0400
@@ -169,14 +169,18 @@
 
 void __kprobes arch_arm_kprobe(struct kprobe *p)
 {
+	kernel_text_lock((unsigned long)p->addr, sizeof(kprobe_opcode_t));
 	*p->addr = BREAKPOINT_INSTRUCTION;
+	kernel_text_unlock((unsigned long)p->addr, sizeof(kprobe_opcode_t));
 	flush_icache_range((unsigned long) p->addr,
 			   (unsigned long) p->addr + sizeof(kprobe_opcode_t));
 }
 
 void __kprobes arch_disarm_kprobe(struct kprobe *p)
 {
+	kernel_text_lock((unsigned long)p->addr, sizeof(kprobe_opcode_t));
 	*p->addr = p->opcode;
+	kernel_text_unlock((unsigned long)p->addr, sizeof(kprobe_opcode_t));
 	flush_icache_range((unsigned long) p->addr,
 			   (unsigned long) p->addr + sizeof(kprobe_opcode_t));
 }

-- 
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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