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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham 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 046EAC433E0 for ; Fri, 25 Dec 2020 08:47:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BFE24230FF for ; Fri, 25 Dec 2020 08:47:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728932AbgLYIrO (ORCPT ); Fri, 25 Dec 2020 03:47:14 -0500 Received: from mail-m964.mail.126.com ([123.126.96.4]:39678 "EHLO mail-m964.mail.126.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725863AbgLYIrN (ORCPT ); Fri, 25 Dec 2020 03:47:13 -0500 X-Greylist: delayed 3655 seconds by postgrey-1.27 at vger.kernel.org; Fri, 25 Dec 2020 03:47:12 EST DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=126.com; s=s110527; h=From:Subject:Date:Message-Id; bh=t5dqagdO7HyDT7ULkT GzWQJ+Y8umPf+mMs4qo4mfeWw=; b=AxRA1QMZNNswizz3Sr4gC0cD6Q1kpsWruU ulDLVH7g8bclikueH3FRx/b3kN5/fEhucPzjyoZUkgYc9lvvkHIVq01bIaPRnyK6 SvMHRHDZoJOYuRSQR65FQKG8Og/EY2CQSSMngKqo4SXrCU8PSHHXYMeCPP4IP6QW OLU+Azo5A= Received: from localhost.localdomain (unknown [36.112.86.14]) by smtp9 (Coremail) with SMTP id NeRpCgB3L3o1n+VfBUQrQA--.7179S2; Fri, 25 Dec 2020 16:13:42 +0800 (CST) From: Defang Bo To: airlied@linux.ie, daniel@ffwll.ch Cc: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Defang Bo Subject: [PATCH 1/2] drivers/gpu/drm/ast: Fix infinite loop if read fails Date: Fri, 25 Dec 2020 16:13:33 +0800 Message-Id: <1608884014-2327765-1-git-send-email-bodefang@126.com> X-Mailer: git-send-email 2.7.4 X-CM-TRANSID: NeRpCgB3L3o1n+VfBUQrQA--.7179S2 X-Coremail-Antispam: 1Uf129KBjvJXoW7uFyDJFW3tryDCr15KF4DJwb_yoW8GF4UpF 47JFyYvrWrtFn0yFW7CF4kWFyrGa97Ja4Fgr97Awn3uF15K3W0vas0kayrKFy7JrZxAFyS qr97tryUX3W8uw7anT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x0zRMKZZUUUUU= X-Originating-IP: [36.112.86.14] X-CM-SenderInfo: pergvwxdqjqiyswou0bp/1tbikhcG11pECE7YtQAAsh Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [Why] Similar to commit <298360af3> ast_init_dram_reg() configures a window in order to access BMC memory. A BMC register can be configured to disallow this, and if so, causes an infinite loop in the ast driver which renders the system unusable. [How] Fix this by erroring out if an error is detected. Signed-off-by: Defang Bo --- drivers/gpu/drm/ast/ast_post.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/ast/ast_post.c b/drivers/gpu/drm/ast/ast_post.c index 8902c2f..ef19c70 100644 --- a/drivers/gpu/drm/ast/ast_post.c +++ b/drivers/gpu/drm/ast/ast_post.c @@ -287,7 +287,9 @@ static void ast_init_dram_reg(struct drm_device *dev) ast_write32(ast, 0x10100, 0xa8); do { - ; + if (pci_channel_offline(dev->pdev)) + return -EIO; + } while (ast_read32(ast, 0x10100) != 0xa8); } else {/* AST2100/1100 */ if (ast->chip == AST2100 || ast->chip == 2200) @@ -299,12 +301,14 @@ static void ast_init_dram_reg(struct drm_device *dev) ast_write32(ast, 0xf000, 0x1); ast_write32(ast, 0x12000, 0x1688A8A8); do { - ; + if (pci_channel_offline(dev->pdev)) + return -EIO; } while (ast_read32(ast, 0x12000) != 0x01); ast_write32(ast, 0x10000, 0xfc600309); do { - ; + if (pci_channel_offline(dev->pdev)) + return -EIO; } while (ast_read32(ast, 0x10000) != 0x01); } -- 2.7.4