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 CC: prasanna@in.ibm.com CC: ananth@in.ibm.com CC: anil.s.keshavamurthy@intel.com CC: davem@davemloft.net --- 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 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/