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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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