From patchwork Thu Feb 6 02:58:23 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jason Yan X-Patchwork-Id: 1234101 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 48Cjwf2bd0z9sRX for ; Thu, 6 Feb 2020 14:05:22 +1100 (AEDT) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=huawei.com Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 48Cjwf1mJKzDqPk for ; Thu, 6 Feb 2020 14:05:22 +1100 (AEDT) X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org 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 48Cjp85hrbzDqTQ for ; Thu, 6 Feb 2020 13:59:42 +1100 (AEDT) Received: from DGGEMS401-HUB.china.huawei.com (unknown [172.30.72.58]) by Forcepoint Email with ESMTP id 2004A7B2BCFD0EE927FF; Thu, 6 Feb 2020 10:59:35 +0800 (CST) Received: from huawei.com (10.175.124.28) by DGGEMS401-HUB.china.huawei.com (10.3.19.201) with Microsoft SMTP Server id 14.3.439.0; Thu, 6 Feb 2020 10:59:28 +0800 From: Jason Yan To: , , , , , , , , , Subject: [PATCH v3 4/6] powerpc/fsl_booke/64: do not clear the BSS for the second pass Date: Thu, 6 Feb 2020 10:58:23 +0800 Message-ID: <20200206025825.22934-5-yanaijie@huawei.com> X-Mailer: git-send-email 2.17.2 In-Reply-To: <20200206025825.22934-1-yanaijie@huawei.com> References: <20200206025825.22934-1-yanaijie@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.175.124.28] 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: Jason Yan , linux-kernel@vger.kernel.org, zhaohongjiang@huawei.com Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" 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 + /* Clear out the BSS. It may have been done in prom_init, * already but that's irrelevant since prom_init will soon * be detached from the kernel completely. Besides, we need