From mboxrd@z Thu Jan 1 00:00:00 1970 From: wangnan0@huawei.com (Wang Nan) Date: Fri, 13 Feb 2015 13:40:48 +0800 Subject: [RFC PATCH v3 13/26] early kprobes: ARM: directly modify code. In-Reply-To: <1423805941-61407-1-git-send-email-wangnan0@huawei.com> References: <1423805941-61407-1-git-send-email-wangnan0@huawei.com> Message-ID: <1423806048-62028-1-git-send-email-wangnan0@huawei.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org For early kprobe, we can simply patch text because we are in a relative simple environment. Signed-off-by: Wang Nan --- arch/arm/probes/kprobes/opt-arm.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/arch/arm/probes/kprobes/opt-arm.c b/arch/arm/probes/kprobes/opt-arm.c index bcdecc2..43446df 100644 --- a/arch/arm/probes/kprobes/opt-arm.c +++ b/arch/arm/probes/kprobes/opt-arm.c @@ -330,8 +330,18 @@ void __kprobes arch_optimize_kprobes(struct list_head *oplist) * Similar to __arch_disarm_kprobe, operations which * removing breakpoints must be wrapped by stop_machine * to avoid racing. + * + * If this function is called before kprobes initialized, + * the kprobe should be an early kprobe, the instruction + * is not armed with breakpoint. There should be only + * one core now, so directly __patch_text is enough. */ - kprobes_remove_breakpoint(op->kp.addr, insn); + if (unlikely(kprobes_is_early())) { + BUG_ON(!(op->kp.flags & KPROBE_FLAG_EARLY)); + __patch_text(op->kp.addr, insn); + } else { + kprobes_remove_breakpoint(op->kp.addr, insn); + } list_del_init(&op->list); } -- 1.8.4