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 <[EMAIL PROTECTED]>
CC: [EMAIL PROTECTED]
CC: [EMAIL PROTECTED]
CC: [EMAIL PROTECTED]
CC: [EMAIL PROTECTED]
---
arch/i386/kernel/kprobes.c | 30 ++++--------------------------
1 file changed, 4 insertions(+), 26 deletions(-)
Index: linux-2.6-lttng/arch/i386/kernel/kprobes.c
===================================================================
--- linux-2.6-lttng.orig/arch/i386/kernel/kprobes.c 2007-06-29
14:15:38.000000000 -0400
+++ linux-2.6-lttng/arch/i386/kernel/kprobes.c 2007-06-29 14:25:08.000000000
-0400
@@ -169,42 +169,20 @@
void __kprobes arch_arm_kprobe(struct kprobe *p)
{
- unsigned long addr = (unsigned long) p->addr;
- int page_readonly = 0;
-
- if (kernel_readonly_text(addr)) {
- page_readonly = 1;
- change_page_attr(virt_to_page(addr), 1, PAGE_KERNEL_RWX);
- global_flush_tlb();
- }
-
+ 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));
-
- if (page_readonly) {
- change_page_attr(virt_to_page(addr), 1, PAGE_KERNEL_RX);
- 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)) {
- page_readonly = 1;
- change_page_attr(virt_to_page(addr), 1, PAGE_KERNEL_RWX);
- global_flush_tlb();
- }
+ 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));
- if (page_readonly) {
- change_page_attr(virt_to_page(addr), 1, PAGE_KERNEL_RX);
- 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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