From patchwork Fri May 22 17:34:19 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: "Gustavo A. R. Silva" X-Patchwork-Id: 11566043 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id F2D17739 for ; Fri, 22 May 2020 17:29:34 +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 D0DBE206D5 for ; Fri, 22 May 2020 17:29:34 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="sw+5iUX6" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D0DBE206D5 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org 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 DE46B6EA10; Fri, 22 May 2020 17:29:30 +0000 (UTC) X-Original-To: dri-devel@lists.freedesktop.org Delivered-To: dri-devel@lists.freedesktop.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by gabe.freedesktop.org (Postfix) with ESMTPS id 9C1746EA10; Fri, 22 May 2020 17:29:29 +0000 (UTC) Received: from embeddedor (unknown [189.207.59.248]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id B7338206C3; Fri, 22 May 2020 17:29:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1590168569; bh=noVq5vIzK2zOX8f731NA23cZdVRrWDncOL4AESsRsPg=; h=Date:From:To:Cc:Subject:From; b=sw+5iUX6i1Ax9MaJRERLYh2ki2CKYhNykMEqas7Ctlfz6msB9sN4MXsg7L1VIWqjx 3RcjOaMXlp6CL6yNlzef+jlOxjnKn6W9NQqhAcMSd5NVEDKs+f70fdKlcVBFj0c8lv XUzwUNpJixMJWyEAI62JI9PKfm3YskgKeQkPkqqM= Date: Fri, 22 May 2020 12:34:19 -0500 From: "Gustavo A. R. Silva" To: Alex Deucher , Christian =?iso-8859-1?q?K=F6n?= =?iso-8859-1?q?ig?= , David Airlie , Daniel Vetter Subject: [PATCH v2] drm/radeon/dpm: Replace one-element array and use struct_size() helper Message-ID: <20200522173419.GA2297@embeddedor> MIME-Version: 1.0 Content-Disposition: inline User-Agent: Mutt/1.9.4 (2018-02-28) 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: "Gustavo A. R. Silva" , dri-devel@lists.freedesktop.org, amd-gfx@lists.freedesktop.org, linux-kernel@vger.kernel.org Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" The current codebase makes use of one-element arrays in the following form: struct something { int length; u8 data[1]; }; struct something *instance; instance = kmalloc(sizeof(*instance) + size, GFP_KERNEL); instance->length = size; memcpy(instance->data, source, size); but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertently introduced[3] to the codebase from now on. So, replace the one-element array with a flexible-array member. Also, make use of the new struct_size() helper to properly calculate the size of struct NISLANDS_SMC_SWSTATE. This issue was found with the help of Coccinelle and, audited and fixed _manually_. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour") Reviewed-by: Christian König Signed-off-by: Gustavo A. R. Silva --- Changes in v2: - Use type size_t instead of u16 for state_size variable. drivers/gpu/drm/amd/amdgpu/si_dpm.h | 2 +- drivers/gpu/drm/radeon/ni_dpm.c | 7 ++++--- 2 files changed, 5 insertions(+), 4 deletions(-) diff --git a/drivers/gpu/drm/amd/amdgpu/si_dpm.h b/drivers/gpu/drm/amd/amdgpu/si_dpm.h index 6b7d292b919f3..bc0be6818e218 100644 --- a/drivers/gpu/drm/amd/amdgpu/si_dpm.h +++ b/drivers/gpu/drm/amd/amdgpu/si_dpm.h @@ -781,7 +781,7 @@ struct NISLANDS_SMC_SWSTATE uint8_t levelCount; uint8_t padding2; uint8_t padding3; - NISLANDS_SMC_HW_PERFORMANCE_LEVEL levels[1]; + NISLANDS_SMC_HW_PERFORMANCE_LEVEL levels[]; }; typedef struct NISLANDS_SMC_SWSTATE NISLANDS_SMC_SWSTATE; diff --git a/drivers/gpu/drm/radeon/ni_dpm.c b/drivers/gpu/drm/radeon/ni_dpm.c index b57c37ddd164c..abb6345bfae32 100644 --- a/drivers/gpu/drm/radeon/ni_dpm.c +++ b/drivers/gpu/drm/radeon/ni_dpm.c @@ -2685,11 +2685,12 @@ static int ni_upload_sw_state(struct radeon_device *rdev, struct rv7xx_power_info *pi = rv770_get_pi(rdev); u16 address = pi->state_table_start + offsetof(NISLANDS_SMC_STATETABLE, driverState); - u16 state_size = sizeof(NISLANDS_SMC_SWSTATE) + - ((NISLANDS_MAX_SMC_PERFORMANCE_LEVELS_PER_SWSTATE - 1) * sizeof(NISLANDS_SMC_HW_PERFORMANCE_LEVEL)); + NISLANDS_SMC_SWSTATE *smc_state; + size_t state_size = struct_size(smc_state, levels, + NISLANDS_MAX_SMC_PERFORMANCE_LEVELS_PER_SWSTATE); int ret; - NISLANDS_SMC_SWSTATE *smc_state = kzalloc(state_size, GFP_KERNEL); + smc_state = kzalloc(state_size, GFP_KERNEL); if (smc_state == NULL) return -ENOMEM;