From patchwork Thu May 7 18:53:56 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Gustavo A. R. Silva" X-Patchwork-Id: 192786 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=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 060E4C38A2A for ; Fri, 8 May 2020 07:35:41 +0000 (UTC) Received: from alsa0.perex.cz (alsa0.perex.cz [77.48.224.243]) (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 8477B20CC7 for ; Fri, 8 May 2020 07:35:40 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=alsa-project.org header.i=@alsa-project.org header.b="qEwwXtXm"; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="GoTy1TOO" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8477B20CC7 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=alsa-devel-bounces@alsa-project.org Received: from alsa1.perex.cz (alsa1.perex.cz [207.180.221.201]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by alsa0.perex.cz (Postfix) with ESMTPS id AE2391857; Fri, 8 May 2020 09:34:48 +0200 (CEST) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa0.perex.cz AE2391857 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=alsa-project.org; s=default; t=1588923338; bh=a3Iyd0AtJyoc/jnDu0wU+xUacgHz++uvOIDW/S793sI=; h=Date:From:To:Subject:Cc:List-Id:List-Unsubscribe:List-Archive: List-Post:List-Help:List-Subscribe:From; b=qEwwXtXmp4zkISMyNukRMYn/MepLQhuTcSLHk2mo/vvz3iYq9dQv40mu6wXcwDkuf L+OsQBY+fcpRseKHy3QpdBAp0DXSAEBfvQ0cwLeJgs3r7uuRLk/67h+L9Sv29O4pBM ESZtZNrg3T2gc5Hc/nizCVN+YXVNzXbjsWYYEKAY= Received: from alsa1.perex.cz (localhost.localdomain [127.0.0.1]) by alsa1.perex.cz (Postfix) with ESMTP id 09608F800F6; Fri, 8 May 2020 09:33:11 +0200 (CEST) Received: by alsa1.perex.cz (Postfix, from userid 50401) id 6F988F8015F; Thu, 7 May 2020 20:49:38 +0200 (CEST) Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by alsa1.perex.cz (Postfix) with ESMTPS id 12D9DF8011C for ; Thu, 7 May 2020 20:49:32 +0200 (CEST) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa1.perex.cz 12D9DF8011C Authentication-Results: alsa1.perex.cz; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="GoTy1TOO" 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 1064C24957; Thu, 7 May 2020 18:49:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588877370; bh=a3Iyd0AtJyoc/jnDu0wU+xUacgHz++uvOIDW/S793sI=; h=Date:From:To:Cc:Subject:From; b=GoTy1TOOPExw6zZPQfNFko/iNKt1k/z1i5fqjYdX7JdD14SrzN9+b7Mp+XiIjR011 +/M0SSI5ZmpPdxy2WwlifmM7c1mb6OYiHPqcxpXS0GB6nnh9tffKTcmbIPBCIPO9f7 amcb8R2XiuBEUYCPw9e1pEBO6Ib7g/K0MkcpieYw= Date: Thu, 7 May 2020 13:53:56 -0500 From: "Gustavo A. R. Silva" To: Cezary Rojewski , Pierre-Louis Bossart , Liam Girdwood , Jie Yang Subject: [PATCH] ASoC: Intel: Skylake: Replace zero-length array with flexible-array Message-ID: <20200507185356.GA14539@embeddedor> MIME-Version: 1.0 Content-Disposition: inline User-Agent: Mutt/1.9.4 (2018-02-28) X-Mailman-Approved-At: Fri, 08 May 2020 09:33:05 +0200 Cc: alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org X-BeenThere: alsa-devel@alsa-project.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: "Alsa-devel mailing list for ALSA developers - http://www.alsa-project.org" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: alsa-devel-bounces@alsa-project.org Sender: "Alsa-devel" The current codebase makes use of the zero-length array language extension to the C90 standard, 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. Also, notice that, dynamic memory allocations won't be affected by this change: "Flexible array members have incomplete type, and so the sizeof operator may not be applied. As a quirk of the original implementation of zero-length arrays, sizeof evaluates to zero."[1] sizeof(flexible-array-member) triggers a warning because flexible array members have incomplete type[1]. There are some instances of code in which the sizeof operator is being incorrectly/erroneously applied to zero-length arrays and the result is zero. Such instances may be hiding some bugs. So, this work (flexible-array member conversions) will also help to get completely rid of those sorts of issues. This issue was found with the help of Coccinelle. [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 --- sound/soc/intel/atom/sst-atom-controls.h | 2 +- sound/soc/intel/skylake/skl-i2s.h | 2 +- sound/soc/intel/skylake/skl-topology.h | 4 ++-- sound/soc/intel/skylake/skl.h | 2 +- 4 files changed, 5 insertions(+), 5 deletions(-) diff --git a/sound/soc/intel/atom/sst-atom-controls.h b/sound/soc/intel/atom/sst-atom-controls.h index 5356e954a732..620b48d2a064 100644 --- a/sound/soc/intel/atom/sst-atom-controls.h +++ b/sound/soc/intel/atom/sst-atom-controls.h @@ -410,7 +410,7 @@ struct sst_cmd_set_gain_dual { struct sst_cmd_set_params { struct sst_destination_id dst; u16 command_id; - char params[0]; + char params[]; } __packed; diff --git a/sound/soc/intel/skylake/skl-i2s.h b/sound/soc/intel/skylake/skl-i2s.h index d7c15873c0d4..dfce91e11be1 100644 --- a/sound/soc/intel/skylake/skl-i2s.h +++ b/sound/soc/intel/skylake/skl-i2s.h @@ -46,7 +46,7 @@ struct skl_i2s_config_mclk { struct skl_i2s_config_mclk_ext { u32 mdivctrl; u32 mdivr_count; - u32 mdivr[0]; + u32 mdivr[]; } __packed; struct skl_i2s_config_blob_signature { diff --git a/sound/soc/intel/skylake/skl-topology.h b/sound/soc/intel/skylake/skl-topology.h index e967800dbb62..d2cd8ef8e97f 100644 --- a/sound/soc/intel/skylake/skl-topology.h +++ b/sound/soc/intel/skylake/skl-topology.h @@ -119,7 +119,7 @@ struct skl_cpr_gtw_cfg { struct skl_dma_control { u32 node_id; u32 config_length; - u32 config_data[0]; + u32 config_data[]; } __packed; struct skl_cpr_cfg { @@ -152,7 +152,7 @@ struct skl_up_down_mixer_cfg { struct skl_algo_cfg { struct skl_base_cfg base_cfg; - char params[0]; + char params[]; } __packed; struct skl_base_outfmt_cfg { diff --git a/sound/soc/intel/skylake/skl.h b/sound/soc/intel/skylake/skl.h index 2bfbf59277c4..26057f38a014 100644 --- a/sound/soc/intel/skylake/skl.h +++ b/sound/soc/intel/skylake/skl.h @@ -49,7 +49,7 @@ struct skl_astate_param { struct skl_astate_config { u32 count; - struct skl_astate_param astate_table[0]; + struct skl_astate_param astate_table[]; }; struct skl_fw_config {