[patch 8/8] 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: prasanna@xxxxxxxxxx
CC: ananth@xxxxxxxxxx
CC: anil.s.keshavamurthy@xxxxxxxxx
CC: davem@xxxxxxxxxxxxx
---
 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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