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

Signed-off-by: Mathieu Desnoyers <[EMAIL PROTECTED]>
CC: [EMAIL PROTECTED]
CC: [EMAIL PROTECTED]
CC: [EMAIL PROTECTED]
CC: [EMAIL PROTECTED]
---
 arch/x86_64/kernel/kprobes.c |   30 ++++--------------------------
 1 file changed, 4 insertions(+), 26 deletions(-)

Index: linux-2.6-lttng/arch/x86_64/kernel/kprobes.c
===================================================================
--- linux-2.6-lttng.orig/arch/x86_64/kernel/kprobes.c   2007-07-13 
16:08:14.000000000 -0400
+++ linux-2.6-lttng/arch/x86_64/kernel/kprobes.c        2007-07-13 
16:41:49.000000000 -0400
@@ -209,42 +209,20 @@
 
 void __kprobes arch_arm_kprobe(struct kprobe *p)
 {
-       unsigned long addr = (unsigned long)p->addr;
-       int page_readonly = 0;
-
-       if (kernel_readonly_text(addr)) {
-               change_page_attr_addr(addr, 1, PAGE_KERNEL_EXEC);
-               global_flush_tlb();
-               page_readonly = 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));
        flush_icache_range((unsigned long) p->addr,
                           (unsigned long) p->addr + sizeof(kprobe_opcode_t));
-       if (page_readonly) {
-               change_page_attr_addr(addr, 1, PAGE_KERNEL_RO);
-               global_flush_tlb();
-       }
 }
 
 void __kprobes arch_disarm_kprobe(struct kprobe *p)
 {
-       unsigned long addr = (unsigned long)p->addr;
-       int page_readonly = 0;
-
-       if (kernel_readonly_text(addr)) {
-               change_page_attr_addr(addr, 1, PAGE_KERNEL_EXEC);
-               global_flush_tlb();
-               page_readonly = 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));
        flush_icache_range((unsigned long) p->addr,
                           (unsigned long) p->addr + sizeof(kprobe_opcode_t));
-
-       if (page_readonly) {
-               change_page_attr_addr(addr, 1, PAGE_KERNEL_RO);
-               global_flush_tlb();
-       }
 }
 
 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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