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Subject[patch 8/8] Text Edit Lock - kprobes x86_64
Kprobes can use the text edit lock to insure mutual exclusion when editing the
code.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
CC: prasanna@in.ibm.com
CC: ananth@in.ibm.com
CC: anil.s.keshavamurthy@intel.com
CC: davem@davemloft.net
---
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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