From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 726D9C32771 for ; Tue, 27 Sep 2022 02:28:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230211AbiI0C2o (ORCPT ); Mon, 26 Sep 2022 22:28:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50956 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230161AbiI0C2X (ORCPT ); Mon, 26 Sep 2022 22:28:23 -0400 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E8CBA9F194; Mon, 26 Sep 2022 19:28:22 -0700 (PDT) Received: from kwepemi500012.china.huawei.com (unknown [172.30.72.56]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4Mc3Pf02shzpTdm; Tue, 27 Sep 2022 10:25:25 +0800 (CST) Received: from huawei.com (10.67.174.53) by kwepemi500012.china.huawei.com (7.221.188.12) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Tue, 27 Sep 2022 10:28:20 +0800 From: Liao Chang To: , , , , , , , , , , CC: , , , Subject: [PATCH 1/3] riscv/kprobe: Optimize the performance of patching single-step slot Date: Tue, 27 Sep 2022 10:24:33 +0800 Message-ID: <20220927022435.129965-2-liaochang1@huawei.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20220927022435.129965-1-liaochang1@huawei.com> References: <20220927022435.129965-1-liaochang1@huawei.com> MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.67.174.53] X-ClientProxiedBy: dggems703-chm.china.huawei.com (10.3.19.180) To kwepemi500012.china.huawei.com (7.221.188.12) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Single-step slot would not be used until kprobe is enabled, that means no race condition occurs on it under SMP, hence it is safe to pacth ss slot without stopping machine. Acked-by: Masami Hiramatsu (Google) Signed-off-by: Liao Chang --- arch/riscv/kernel/probes/kprobes.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/arch/riscv/kernel/probes/kprobes.c b/arch/riscv/kernel/probes/kprobes.c index e6e950b7cf32..bc1f39b96e41 100644 --- a/arch/riscv/kernel/probes/kprobes.c +++ b/arch/riscv/kernel/probes/kprobes.c @@ -24,12 +24,14 @@ post_kprobe_handler(struct kprobe *, struct kprobe_ctlblk *, struct pt_regs *); static void __kprobes arch_prepare_ss_slot(struct kprobe *p) { unsigned long offset = GET_INSN_LENGTH(p->opcode); + kprobe_opcode_t slot[MAX_INSN_SIZE]; p->ainsn.api.restore = (unsigned long)p->addr + offset; - patch_text(p->ainsn.api.insn, p->opcode); - patch_text((void *)((unsigned long)(p->ainsn.api.insn) + offset), - __BUG_INSN_32); + memcpy(slot, &p->opcode, offset); + *(kprobe_opcode_t *)((unsigned long)slot + offset) = __BUG_INSN_32; + patch_text_nosync(p->ainsn.api.insn, slot, + offset + GET_INSN_LENGTH(__BUG_INSN_32)); } static void __kprobes arch_prepare_simulate(struct kprobe *p) -- 2.17.1