From patchwork Sun Nov 27 14:41:15 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jonathan Cameron X-Patchwork-Id: 628905 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 196A1C352A1 for ; Sun, 27 Nov 2022 14:29:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229681AbiK0O3G (ORCPT ); Sun, 27 Nov 2022 09:29:06 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41144 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229690AbiK0O3E (ORCPT ); Sun, 27 Nov 2022 09:29:04 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 33CC4DFF3 for ; Sun, 27 Nov 2022 06:29:04 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id C10AA60DC8 for ; Sun, 27 Nov 2022 14:29:03 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 40566C433C1; Sun, 27 Nov 2022 14:29:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1669559343; bh=QsL8vDZaeyn70YUIfKe1Z7n3hslJX8WYpKdZzZmdcTc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=NtPni+349EamRADKKGpJZ9fqq/ONta2ohnash1+mydVAizXpAda/2jpd3nSs7STz8 P3VMG65P0vB6eVbYhV0Piywdz3mGdY5F006BHZfTlDqclZPsKlE/8Z+3b0/YYWWFE6 yvxZniY8hNRHJC2wm6+N/e2KzxZa9Jy56tFrmtR/ngysyrPDlfFj0HV8U9BmlDnKY9 beGSTef+sEyI/xXq2lT8X/YQbfkZHPau0uZwhfWnfTa0rTol3TG9nui6CaFhc6FIVz sye0QcgCLDaBE5wXq4qGm8EEGBdDxHqjJZSQBnPS7esVXS+CLqaCUNaOyQshD3bFo7 XnRu1klQtWTCQ== From: Jonathan Cameron To: linux-input@vger.kernel.org, Dmitry Torokhov Cc: Jonathan Cameron , Daniel Hung-yu Wu Subject: [PATCH 8/9] Input: atmel_captouch - Avoid suspect DMA buffer alignment. Date: Sun, 27 Nov 2022 14:41:15 +0000 Message-Id: <20221127144116.1418083-9-jic23@kernel.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221127144116.1418083-1-jic23@kernel.org> References: <20221127144116.1418083-1-jic23@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-input@vger.kernel.org From: Jonathan Cameron On some architectures (e.g. arm64), ____cachline_aligned only aligns to the cacheline size of the L1 cache size. L1_CACHE_BYTES in arch64/include/asm/cache.h Unfortunately DMA safety on these architectures requires the buffer no share a last level cache cacheline given by ARCH_DMA_MINALIGN which has a greater granularity. ARCH_DMA_MINALIGN is not defined for all architectures, but when it is defined it is used to set the size of ARCH_KMALLOC_MINALIGN to allow DMA safe buffer allocations. As such the correct alignment requirement is __aligned(ARCH_KMALLOC_MINALIGN). This has recently been fixed in other subsystems such as IIO. This is probably not a fix as such, because likely this particular device is only used on devices where the given alignment is sufficient. Signed-off-by: Jonathan Cameron Cc: Daniel Hung-yu Wu --- drivers/input/misc/atmel_captouch.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/input/misc/atmel_captouch.c b/drivers/input/misc/atmel_captouch.c index 051aded6815a..9681c763356c 100644 --- a/drivers/input/misc/atmel_captouch.c +++ b/drivers/input/misc/atmel_captouch.c @@ -71,7 +71,7 @@ struct atmel_captouch_device { u32 num_btn; u32 keycodes[MAX_NUM_OF_BUTTONS]; u8 prev_btn; - u8 xfer_buf[8] ____cacheline_aligned; + u8 xfer_buf[8] __aligned(ARCH_KMALLOC_MINALIGN); }; /*