From patchwork Fri Sep 23 08:46:58 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Liao, Chang" X-Patchwork-Id: 12986325 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 C5C2FECAAD8 for ; Fri, 23 Sep 2022 08:52:04 +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=SX5CD+VP96A66smigy3nEEILjGcm1nyT2qjl4LcpDH4=; b=jbEmBULkz3SaO5 AhaMLwvo3i2xWU6XnM8SfcrROuwI+IL6JIi29FxIESwKZLhwalNhdW1EoRYKNPSopaltYblsxXzrK gzYLDypu+xVDVAGVKnELaBPxEzBXRInO9Hqqs2qWRm+NiBlJTSMGIEHv97jJPBmGeeh5Q8BPP2Lai UoDssx1NLggW8qBTOrqFvhtcVm4p2PxfE+BJUt0G+jmqDpuNcC8qjC8gnmR9dNgCDj/VkMVyU8RVS hfgJ9DAUWLMeiZUbfHjTaJYTQ5RaZs3UdvxAb/qN+S3yZekM6SwI6jJbbEvzmsmKyJNhWLpCpvKs+ JqEPxKEusSMWcGaAnGpw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1obeOe-0033Vs-Dl; Fri, 23 Sep 2022 08:50:56 +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 1obeOS-0033R6-EI; Fri, 23 Sep 2022 08:50:45 +0000 Received: from kwepemi500012.china.huawei.com (unknown [172.30.72.53]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4MYm3Q4S2lzWgy5; Fri, 23 Sep 2022 16:46:42 +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; Fri, 23 Sep 2022 16:50:40 +0800 From: Liao Chang To: , , , , , , , , , , , CC: , , , Subject: [PATCH 3/3] arm64/kprobe: Optimize the performance of patching single-step slot Date: Fri, 23 Sep 2022 16:46:58 +0800 Message-ID: <20220923084658.99304-4-liaochang1@huawei.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20220923084658.99304-1-liaochang1@huawei.com> References: <20220923084658.99304-1-liaochang1@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.67.174.53] X-ClientProxiedBy: dggems704-chm.china.huawei.com (10.3.19.181) 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-20220923_015044_694985_B17AF750 X-CRM114-Status: UNSURE ( 9.23 ) 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. Since I and D caches are coherent within single-step slot from aarch64_insn_patch_text_nosync(), hence no need to do it again via flush_icache_range(). Acked-by: Masami Hiramatsu (Google) Signed-off-by: Liao Chang Acked-by: Will Deacon --- arch/arm64/kernel/probes/kprobes.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) diff --git a/arch/arm64/kernel/probes/kprobes.c b/arch/arm64/kernel/probes/kprobes.c index d1d182320245..29b98bc12833 100644 --- a/arch/arm64/kernel/probes/kprobes.c +++ b/arch/arm64/kernel/probes/kprobes.c @@ -44,13 +44,10 @@ post_kprobe_handler(struct kprobe *, struct kprobe_ctlblk *, struct pt_regs *); static void __kprobes arch_prepare_ss_slot(struct kprobe *p) { kprobe_opcode_t *addr = p->ainsn.api.insn; - void *addrs[] = {addr, addr + 1}; - u32 insns[] = {p->opcode, BRK64_OPCODE_KPROBES_SS}; /* prepare insn slot */ - aarch64_insn_patch_text(addrs, insns, 2); - - flush_icache_range((uintptr_t)addr, (uintptr_t)(addr + MAX_INSN_SIZE)); + aarch64_insn_patch_text_nosync(addr, p->opcode); + aarch64_insn_patch_text_nosync(addr + 1, BRK64_OPCODE_KPROBES_SS); /* * Needs restoring of return address after stepping xol.