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=-13.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 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 D29BCC433E0 for ; Fri, 22 May 2020 01:21:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9D30A207F7 for ; Fri, 22 May 2020 01:21:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1590110460; bh=2+PPWtAtIWrXh8GHaxR6UZHkYVkCWucHPcLYyfkfZjg=; h=Date:From:To:Cc:Subject:List-ID:From; b=xLoWd/0bW2EqlD5EheNnKYKr3IEfPhDegazAX+3eX+U0kczH/8klRiUDmoAqoAUqR AkWnjZP6HOPuQ2lEE9UugLzPYXTg9TY8dTKUS2AqV4DVRo9kQe4cCf0olUE4AG3nnQ JvwlzTEi6VML8x7Nw4UHlZHPK3LTG4zcRYFJDaIQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727069AbgEVBU7 (ORCPT ); Thu, 21 May 2020 21:20:59 -0400 Received: from mail.kernel.org ([198.145.29.99]:54420 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726737AbgEVBU7 (ORCPT ); Thu, 21 May 2020 21:20:59 -0400 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 1C568207D8; Fri, 22 May 2020 01:20:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1590110458; bh=2+PPWtAtIWrXh8GHaxR6UZHkYVkCWucHPcLYyfkfZjg=; h=Date:From:To:Cc:Subject:From; b=xG3o7F2/P+VdCTnXo4QWqPyFSMVI8Fy2R3lkyvwLIfDCWDd318uMpZrIHpMXDenuj 2Rs1PL0DBHzCHn3vjzwbPtGCVi9OVhImQqdORChYY3pnhrOPASQl7OApA7tC3yBsdY S7l4Oumx61oWHzX7Nk6mHHXg+AmWDna992KeSVTg= Date: Thu, 21 May 2020 20:25:47 -0500 From: "Gustavo A. R. Silva" To: Alex Deucher , Christian =?iso-8859-1?Q?K=F6nig?= , David Airlie , Daniel Vetter Cc: amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, "Gustavo A. R. Silva" Subject: [PATCH] drm/radeon/dpm: Replace one-element array and use struct_size() helper Message-ID: <20200522012547.GA6783@embeddedor> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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") Signed-off-by: Gustavo A. R. Silva --- 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..7d81dde509dc9 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; + u16 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; -- 2.26.2