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=-19.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT 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 50E03C433EF for ; Thu, 16 Sep 2021 16:21:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 39D3F619E3 for ; Thu, 16 Sep 2021 16:21:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234808AbhIPQXR (ORCPT ); Thu, 16 Sep 2021 12:23:17 -0400 Received: from mail.kernel.org ([198.145.29.99]:49032 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239499AbhIPQNU (ORCPT ); Thu, 16 Sep 2021 12:13:20 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id ADC0D61130; Thu, 16 Sep 2021 16:09:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1631808597; bh=6dNN8OQPe/wsB34uoI/ICMKD2qSsK5yWqTj8ezysK4A=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=J4hvoDJTaNBDBnLL34ofPh1u+rWKfuQmz98f+FaAoEq8A6oBj6aVnLrMdA0+DmGiT Jz3Ws7IwJq5aA5fHuG4FvNCqhZOyOhZIscZyjrgUTDtdTT7J6+ayywGsp8GJBJPyu9 V+d/6VrZYXuRAfwnz3OX7zrUKXqkHpTT9Hy32/z0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Geert Uytterhoeven , Fabio Estevam , Laurent Pinchart , Sam Ravnborg , Sasha Levin Subject: [PATCH 5.10 152/306] drm/bridge: nwl-dsi: Avoid potential multiplication overflow on 32-bit Date: Thu, 16 Sep 2021 17:58:17 +0200 Message-Id: <20210916155759.259566163@linuxfoundation.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20210916155753.903069397@linuxfoundation.org> References: <20210916155753.903069397@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Geert Uytterhoeven [ Upstream commit 47956bc86ee4e8530cac386a04f62a6095f7afbe ] As nwl_dsi.lanes is u32, and NSEC_PER_SEC is 1000000000L, the second multiplication in dsi->lanes * 8 * NSEC_PER_SEC will overflow on a 32-bit platform. Fix this by making the constant unsigned long long, forcing 64-bit arithmetic. As iMX8 is arm64, this driver is currently used on 64-bit platforms only, where long is 64-bit, so this cannot happen. But the issue will start to happen when the driver is reused for a 32-bit SoC (e.g. i.MX7ULP), or when code is copied for a new driver. Signed-off-by: Geert Uytterhoeven Reviewed-by: Fabio Estevam Reviewed-by: Laurent Pinchart Signed-off-by: Sam Ravnborg Link: https://patchwork.freedesktop.org/patch/msgid/ebb82941a86b4e35c4fcfb1ef5a5cfad7c1fceab.1626255956.git.geert+renesas@glider.be Signed-off-by: Sasha Levin --- drivers/gpu/drm/bridge/nwl-dsi.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/gpu/drm/bridge/nwl-dsi.c b/drivers/gpu/drm/bridge/nwl-dsi.c index c65ca860712d..6cac2e58cd15 100644 --- a/drivers/gpu/drm/bridge/nwl-dsi.c +++ b/drivers/gpu/drm/bridge/nwl-dsi.c @@ -196,7 +196,7 @@ static u32 ps2bc(struct nwl_dsi *dsi, unsigned long long ps) u32 bpp = mipi_dsi_pixel_format_to_bpp(dsi->format); return DIV64_U64_ROUND_UP(ps * dsi->mode.clock * bpp, - dsi->lanes * 8 * NSEC_PER_SEC); + dsi->lanes * 8ULL * NSEC_PER_SEC); } /* -- 2.30.2