From patchwork Tue Sep 13 03:34:52 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Liao, Chang" X-Patchwork-Id: 12974307 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 0411BC6FA82 for ; Tue, 13 Sep 2022 03:40:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-ID:Date:Subject:CC:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=PpyH3cWOR+3jgui5eSElhxY4c7fNgGeyJDqLi2C4bRE=; b=2LHA4d2om9tcn6 V6sgIfb5nC+PJKpJCH4TchJyqx/+OmLURF3wy37FmQHiq6/30093yrMJZ0b2+1nSRLDH2ulxUxFwp qlSfvD4d65FjGj6/cQq7Z3waAiUOio3Da9kYpnl2TJ1BpzQEvS8A+mlMAMTl+0o7jQQmbGWedl5/r QJg/WdkGnviwgzR2O9DMmwqDBJ3nP8B1h1tAMeKS0xMbXYMzEBsrC8OgJI+wLZ8mnCwFooL+vDPcV AnWUVz0yIlqs23GdKlqV1Rj3sG+0fqrfBzv7eUfreFUnQcSIrFSYgBNCbw/t9PiBgYJdFTwlpm31U Cyxm52bqrtdOfXHEJ2nw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1oXwlP-0014Mm-7U; Tue, 13 Sep 2022 03:39:07 +0000 Received: from szxga02-in.huawei.com ([45.249.212.188]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1oXwko-0013wu-QS; Tue, 13 Sep 2022 03:38:33 +0000 Received: from kwepemi500012.china.huawei.com (unknown [172.30.72.55]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4MRTb322LvzNmF7; Tue, 13 Sep 2022 11:33:51 +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 15.1.2375.24; Tue, 13 Sep 2022 11:38:25 +0800 From: Liao Chang To: , , , , , , , , , , CC: , , , Subject: [PATCH V2 1/3] riscv/kprobe: Optimize the performance of patching single-step slot Date: Tue, 13 Sep 2022 11:34:52 +0800 Message-ID: <20220913033454.104519-2-liaochang1@huawei.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20220913033454.104519-1-liaochang1@huawei.com> References: <20220913033454.104519-1-liaochang1@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.67.174.53] X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To kwepemi500012.china.huawei.com (7.221.188.12) X-CFilter-Loop: Reflected X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220912_203831_062626_4141C141 X-CRM114-Status: UNSURE ( 8.39 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.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. 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)