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=-15.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,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 4EC89C2D0E0 for ; Tue, 15 Sep 2020 16:22:41 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (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 0671A20708 for ; Tue, 15 Sep 2020 16:22:40 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="JALBWiar" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0671A20708 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=canonical.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:MIME-Version:Message-Id:Date:Subject:To:From: Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender :Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References:List-Owner; bh=zDNMl8VwjIH4RmwlfaBfh9R/OHyI70AP5x75up0RfpE=; b=JALBWiarQ8QcUwMs0s3A/NJegS 4Y5004BQFuExT2hzOVnOjcl9csyKOr5m60L253C7lPqcE4gnxj7xw6LI7hjLoP9yp0BMefHeGBqHG KNzqfcS7zcw5y/7Woo1hg9maLzeATQnDey/tYN4jX3gxQR8msa2jaZKsEiFAvUBfOi8Nfn/SZ9YQl takTz01twgb2x1aEEm5xerZHoTRsFuxLktvl0ZJHFcKsyGbs8QQ1Dx456V3SwKbjKE/6vvcvNSOmg 4rnWl6wM4XdMfitpSWyLtf/HAZVF4VCLcfeWCapHl8SbVmFUBmxBq2HupBwdnVH+RjG8Ju3hnf5QE hX8VtEug==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kIDhZ-00018D-JP; Tue, 15 Sep 2020 16:21:05 +0000 Received: from youngberry.canonical.com ([91.189.89.112]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kIDhS-00016R-0P; Tue, 15 Sep 2020 16:20:59 +0000 Received: from 1.general.cking.uk.vpn ([10.172.193.212] helo=localhost) by youngberry.canonical.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.86_2) (envelope-from ) id 1kIDhJ-0007yl-QR; Tue, 15 Sep 2020 16:20:49 +0000 From: Colin King To: Sandy Huang , =?UTF-8?q?Heiko=20St=C3=BCbner?= , David Airlie , Daniel Vetter , Chris Zhong , Guenter Roeck , Sean Paul , dri-devel@lists.freedesktop.org, linux-arm-kernel@lists.infradead.org, linux-rockchip@lists.infradead.org Subject: [PATCH] drm/rockchip: cdn-dp: fix sign extension on an int multiply for a u64 result Date: Tue, 15 Sep 2020 17:20:49 +0100 Message-Id: <20200915162049.36434-1-colin.king@canonical.com> X-Mailer: git-send-email 2.27.0 MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200915_122058_173528_94B5C92E X-CRM114-Status: GOOD ( 14.60 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org From: Colin Ian King The variable bit_per_pix is a u8 and is promoted in the multiplication to an int type and then sign extended to a u64. If the result of the int multiplication is greater than 0x7fffffff then the upper 32 bits will be set to 1 as a result of the sign extension. Avoid this by casting tu_size_reg to u64 to avoid sign extension and also a potential overflow. Addresses-Coverity: ("Unintended sign extension") Fixes: 1a0f7ed3abe2 ("drm/rockchip: cdn-dp: add cdn DP support for rk3399") Signed-off-by: Colin Ian King --- drivers/gpu/drm/rockchip/cdn-dp-reg.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/gpu/drm/rockchip/cdn-dp-reg.c b/drivers/gpu/drm/rockchip/cdn-dp-reg.c index 9d2163ef4d6e..33fb4d05c506 100644 --- a/drivers/gpu/drm/rockchip/cdn-dp-reg.c +++ b/drivers/gpu/drm/rockchip/cdn-dp-reg.c @@ -658,7 +658,7 @@ int cdn_dp_config_video(struct cdn_dp_device *dp) */ do { tu_size_reg += 2; - symbol = tu_size_reg * mode->clock * bit_per_pix; + symbol = (u64)tu_size_reg * mode->clock * bit_per_pix; do_div(symbol, dp->max_lanes * link_rate * 8); rem = do_div(symbol, 1000); if (tu_size_reg > 64) { -- 2.27.0 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel