From patchwork Wed Jan 7 07:35:33 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wang Nan X-Patchwork-Id: 5582961 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id D6A8DBF6C3 for ; Wed, 7 Jan 2015 07:44:25 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 16F212025B for ; Wed, 7 Jan 2015 07:44:25 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 3D4A12024F for ; Wed, 7 Jan 2015 07:44:24 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1Y8lFT-0004Yh-OB; Wed, 07 Jan 2015 07:41:47 +0000 Received: from szxga02-in.huawei.com ([119.145.14.65]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1Y8lF5-00045b-L2 for linux-arm-kernel@lists.infradead.org; Wed, 07 Jan 2015 07:41:24 +0000 Received: from 172.24.2.119 (EHLO lggeml421-hub.china.huawei.com) ([172.24.2.119]) by szxrg02-dlp.huawei.com (MOS 4.3.7-GA FastPath queued) with ESMTP id CFA93930; Wed, 07 Jan 2015 15:40:45 +0800 (CST) Received: from kernel-host.huawei (10.107.197.247) by lggeml421-hub.china.huawei.com (10.72.61.31) with Microsoft SMTP Server id 14.3.158.1; Wed, 7 Jan 2015 15:40:35 +0800 From: Wang Nan To: , , , , , , , , Subject: [RFC PATCH 03/11] x86: kprobes: directly modify code if kprobe is not initialized. Date: Wed, 7 Jan 2015 15:35:33 +0800 Message-ID: <1420616133-42855-1-git-send-email-wangnan0@huawei.com> X-Mailer: git-send-email 1.8.4 In-Reply-To: <1420616086-42692-1-git-send-email-wangnan0@huawei.com> References: <1420616086-42692-1-git-send-email-wangnan0@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.107.197.247] X-CFilter-Loop: Reflected X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20150106_234124_104588_5863C56C X-CRM114-Status: UNSURE ( 6.87 ) X-CRM114-Notice: Please train this message. X-Spam-Score: -0.7 (/) Cc: lizefan@huawei.com, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-4.2 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP When registering early kprobes, SMP should has not been enabled, so doesn't require synchronization in text_poke_bp(). Simply memcpy is enough. Signed-off-by: Wang Nan --- arch/x86/kernel/kprobes/opt.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/kprobes/opt.c b/arch/x86/kernel/kprobes/opt.c index 0dd8d08..dc5fccb 100644 --- a/arch/x86/kernel/kprobes/opt.c +++ b/arch/x86/kernel/kprobes/opt.c @@ -397,8 +397,11 @@ void arch_optimize_kprobes(struct list_head *oplist) insn_buf[0] = RELATIVEJUMP_OPCODE; *(s32 *)(&insn_buf[1]) = rel; - text_poke_bp(op->kp.addr, insn_buf, RELATIVEJUMP_SIZE, - op->optinsn.insn); + if (unlikely(!kprobes_initialized)) + memcpy(op->kp.addr, insn_buf, RELATIVEJUMP_SIZE); + else + text_poke_bp(op->kp.addr, insn_buf, RELATIVEJUMP_SIZE, + op->optinsn.insn); list_del_init(&op->list); }