From patchwork Thu Feb 12 12:20:29 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wang Nan X-Patchwork-Id: 5819341 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 6411ABF440 for ; Thu, 12 Feb 2015 12:40:36 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 9CE0020220 for ; Thu, 12 Feb 2015 12:40:35 +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 C0BA92012E for ; Thu, 12 Feb 2015 12:40:34 +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 1YLt1V-0003M3-9T; Thu, 12 Feb 2015 12:37:37 +0000 Received: from szxga01-in.huawei.com ([119.145.14.64]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1YLstD-0000Rb-Cv for linux-arm-kernel@lists.infradead.org; Thu, 12 Feb 2015 12:29:04 +0000 Received: from 172.24.2.119 (EHLO lggeml426-hub.china.huawei.com) ([172.24.2.119]) by szxrg01-dlp.huawei.com (MOS 4.3.7-GA FastPath queued) with ESMTP id CJL31445; Thu, 12 Feb 2015 20:27:20 +0800 (CST) Received: from kernel-host.huawei (10.107.197.247) by lggeml426-hub.china.huawei.com (10.72.61.36) with Microsoft SMTP Server id 14.3.158.1; Thu, 12 Feb 2015 20:27:09 +0800 From: Wang Nan To: , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , Subject: [RFC PATCH v2 13/26] early kprobes: ARM: directly modify code. Date: Thu, 12 Feb 2015 20:20:29 +0800 Message-ID: <1423743629-12584-1-git-send-email-wangnan0@huawei.com> X-Mailer: git-send-email 1.8.4 In-Reply-To: <1423743476-11927-1-git-send-email-wangnan0@huawei.com> References: <1423743476-11927-1-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-20150212_042903_671032_697DA1AB X-CRM114-Status: UNSURE ( 7.93 ) X-CRM114-Notice: Please train this message. X-Spam-Score: -0.7 (/) Cc: lizefan@huawei.com, x86@kernel.org, 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 For early kprobe, we can simply patch text because we are in a relative simple environment. Signed-off-by: Wang Nan --- arch/arm/probes/kprobes/opt-arm.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/arch/arm/probes/kprobes/opt-arm.c b/arch/arm/probes/kprobes/opt-arm.c index bcdecc2..43446df 100644 --- a/arch/arm/probes/kprobes/opt-arm.c +++ b/arch/arm/probes/kprobes/opt-arm.c @@ -330,8 +330,18 @@ void __kprobes arch_optimize_kprobes(struct list_head *oplist) * Similar to __arch_disarm_kprobe, operations which * removing breakpoints must be wrapped by stop_machine * to avoid racing. + * + * If this function is called before kprobes initialized, + * the kprobe should be an early kprobe, the instruction + * is not armed with breakpoint. There should be only + * one core now, so directly __patch_text is enough. */ - kprobes_remove_breakpoint(op->kp.addr, insn); + if (unlikely(kprobes_is_early())) { + BUG_ON(!(op->kp.flags & KPROBE_FLAG_EARLY)); + __patch_text(op->kp.addr, insn); + } else { + kprobes_remove_breakpoint(op->kp.addr, insn); + } list_del_init(&op->list); }