From patchwork Tue Sep 13 03:34:54 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Liao, Chang" X-Patchwork-Id: 12974310 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 7611EC6FA82 for ; Tue, 13 Sep 2022 03:39:40 +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=RSSt9lcwQ3vm65vOGCHqZSmAVeBdv3NbmnAmpE0CkEk=; b=yhu1Gkb95xS/Wg Py9zEU22lPwaK5cJU3D9dMESdnGj7fONRBEPdkkYbYfe/SfUVrA2RrZdNp9S/6ckdJCL30xGfERa4 P+4Sc8XSqTcJ5kw0a3YwoF9CNilAM0nR0Tx0oG34IRUtTaPfTbiZ9A6K3zV9PGKzAi+HchkqA7ugA 5EqHpIg8zUzSH5CvCPjnQZf5doCqEINxgvc4zJCCDjcagMM2FDm2pTaDelgzcB1DKVnNoX7jQk6tS ABjI9UEmNK6Q71juWxbIpPPwfGLozPFsKjtR21HER/jYdvo/J5IULE+c1hqzec4vURm+fmCQkUzVS 2P1hXOBY/bsIdKb8iBKQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1oXwlY-0014XZ-Qr; Tue, 13 Sep 2022 03:39:16 +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-0013x9-QE; 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 4MRTc36KtyzmV5w; Tue, 13 Sep 2022 11:34:43 +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 11:38:26 +0800 From: Liao Chang To: , , , , , , , , , , CC: , , , Subject: [PATCH V2 3/3] arm64/kprobe: Optimize the performance of patching single-step slot Date: Tue, 13 Sep 2022 11:34:54 +0800 Message-ID: <20220913033454.104519-4-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_063925_AEE41E17 X-CRM114-Status: UNSURE ( 8.59 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-riscv@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-riscv" Errors-To: linux-riscv-bounces+linux-riscv=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/arm64/kernel/probes/kprobes.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/arch/arm64/kernel/probes/kprobes.c b/arch/arm64/kernel/probes/kprobes.c index d1d182320245..5902e33fd3b6 100644 --- a/arch/arm64/kernel/probes/kprobes.c +++ b/arch/arm64/kernel/probes/kprobes.c @@ -44,11 +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); + aarch64_insn_write(addr, p->opcode); + aarch64_insn_write(addr + 1, BRK64_OPCODE_KPROBES_SS); flush_icache_range((uintptr_t)addr, (uintptr_t)(addr + MAX_INSN_SIZE));