From patchwork Fri Dec 25 08:13:33 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Defang Bo X-Patchwork-Id: 11990027 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=-13.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 577E5C433E6 for ; Fri, 25 Dec 2020 09:43:28 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (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 2C246230FF for ; Fri, 25 Dec 2020 09:43:28 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2C246230FF Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=126.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 9E07D89CC9; Fri, 25 Dec 2020 09:42:19 +0000 (UTC) Received: from mail-m964.mail.126.com (mail-m964.mail.126.com [123.126.96.4]) by gabe.freedesktop.org (Postfix) with ESMTPS id 59DB4898C8 for ; Fri, 25 Dec 2020 08:13:51 +0000 (UTC) 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 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 X-Mailman-Approved-At: Fri, 25 Dec 2020 09:42:09 +0000 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Defang Bo , linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org MIME-Version: 1.0 Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" [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); }