From patchwork Tue Sep 27 02:24:33 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Liao, Chang" X-Patchwork-Id: 12989706 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 10E57C32771 for ; Tue, 27 Sep 2022 02:29:55 +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=5jnKj6mcgjAxium0NpAm7lsZnAggh5CDGL0BFLTmVoU=; b=yTdh5AtpUAxGvQ HY1HPNs3xBztBSRcs0f504t2/NGuej/3dkC7FiA6WJ8EpMQIcrp3ldd9j6FeLGMnPedcobK+kIebm sidChdIRCYgo2r6FvvVtBQ6xgbRp/EzqVqoXlSA2B3Vk7clT8OR+SRTM81EpBRTQ9fjJ6X+z/NabP BfczKwPdiuICdcODEZvl2TRade44A6vNcTi332xY6LYx6ACsXZaq7JZtmdRlxdmWqDHGRscLNHOJ3 McX39SCQiAZtpgTTtCrZF2xPhV3wchTGzqXlsq5asAMu/Qc5kNROIy5Pjr0GdELal8CyjlNElZbkT o0QJZvhOOKRCxj8cwJpg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1od0Ko-007q0Q-Uu; Tue, 27 Sep 2022 02:28:35 +0000 Received: from szxga01-in.huawei.com ([45.249.212.187]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1od0Kk-007pyM-Sv; Tue, 27 Sep 2022 02:28:32 +0000 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 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 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220926_192831_127185_19702739 X-CRM114-Status: UNSURE ( 8.93 ) 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. 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)