From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 94D32C3F2D1 for ; Thu, 5 Mar 2020 03:16:52 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 4C8AA20870 for ; Thu, 5 Mar 2020 03:16:52 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4C8AA20870 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 48Xwrx69bzzDqkj for ; Thu, 5 Mar 2020 14:16:49 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=huawei.com (client-ip=45.249.212.35; helo=huawei.com; envelope-from=yanaijie@huawei.com; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=huawei.com Received: from huawei.com (szxga07-in.huawei.com [45.249.212.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 48Xwq76LStzDqdn for ; Thu, 5 Mar 2020 14:15:15 +1100 (AEDT) Received: from DGGEMS409-HUB.china.huawei.com (unknown [172.30.72.60]) by Forcepoint Email with ESMTP id B11B318CE46A3B88F89C; Thu, 5 Mar 2020 11:15:07 +0800 (CST) Received: from [127.0.0.1] (10.173.221.195) by DGGEMS409-HUB.china.huawei.com (10.3.19.209) with Microsoft SMTP Server id 14.3.439.0; Thu, 5 Mar 2020 11:14:59 +0800 Subject: Re: [PATCH v3 4/6] powerpc/fsl_booke/64: do not clear the BSS for the second pass To: Scott Wood , , , , , , , , , References: <20200206025825.22934-1-yanaijie@huawei.com> <20200206025825.22934-5-yanaijie@huawei.com> From: Jason Yan Message-ID: Date: Thu, 5 Mar 2020 11:14:59 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:68.0) Gecko/20100101 Thunderbird/68.4.2 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.173.221.195] X-CFilter-Loop: Reflected X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-kernel@vger.kernel.org, zhaohongjiang@huawei.com Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" 在 2020/3/5 5:49, Scott Wood 写道: > On Thu, 2020-02-06 at 10:58 +0800, Jason Yan wrote: >> The BSS section has already cleared out in the first pass. No need to >> clear it again. This can save some time when booting with KASLR >> enabled. >> >> Signed-off-by: Jason Yan >> Cc: Scott Wood >> Cc: Diana Craciun >> Cc: Michael Ellerman >> Cc: Christophe Leroy >> Cc: Benjamin Herrenschmidt >> Cc: Paul Mackerras >> Cc: Nicholas Piggin >> Cc: Kees Cook >> --- >> arch/powerpc/kernel/head_64.S | 7 +++++++ >> 1 file changed, 7 insertions(+) >> >> diff --git a/arch/powerpc/kernel/head_64.S b/arch/powerpc/kernel/head_64.S >> index 744624140fb8..8c644e7c3eaf 100644 >> --- a/arch/powerpc/kernel/head_64.S >> +++ b/arch/powerpc/kernel/head_64.S >> @@ -914,6 +914,13 @@ start_here_multiplatform: >> bl relative_toc >> tovirt(r2,r2) >> >> + /* Do not clear the BSS for the second pass if randomized */ >> + LOAD_REG_ADDR(r3, kernstart_virt_addr) >> + lwz r3,0(r3) >> + LOAD_REG_IMMEDIATE(r4, KERNELBASE) >> + cmpw r3,r4 >> + bne 4f > > These are 64-bit values. > Oh yes, will fix. Thanks. > -Scott > > > > . >