From patchwork Mon Mar 27 12:13:04 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Arnd Bergmann X-Patchwork-Id: 13189116 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 B13B3C7619A for ; Mon, 27 Mar 2023 12:16:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232804AbjC0MP6 (ORCPT ); Mon, 27 Mar 2023 08:15:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35082 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232734AbjC0MP2 (ORCPT ); Mon, 27 Mar 2023 08:15:28 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2A86F4220; Mon, 27 Mar 2023 05:15:09 -0700 (PDT) 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 ams.source.kernel.org (Postfix) with ESMTPS id 6C199B8117B; Mon, 27 Mar 2023 12:15:08 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0A790C4339E; Mon, 27 Mar 2023 12:14:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1679919307; bh=p+eG9OtxIwlFEHuBl1BynARl6RQHBxG84PbOJSDaMSg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=k7yTj16MC4QC0lUkI+OlRgN70GEfUAXZsHUm34awwsfDq+uuBVpGn8XzMpAYzrKep rzfZf9IvuTrt/evwGGuCXfuT5QwwzcXZODB9YgjYpxv0iZgT9rwRfHG1vVFKHMnR80 WkjKXapkPoQqpX0z8bvvlpG0YOBt+p7Spw/IdU0XpPUFOYiASiKd39EeZPyxyEYUJn 9ZY055tF4c7BVKMQhNCmNKfo+NgnV/grwYyrPuAwvgV7tJNlhsepLbNs91InZGtrtI 0UOObEmqhXtHeujJTAybyrsno6jtIGCIZbfee+GXSUa8z2HvG7G/GO5AeAihPvul14 jCOgl+Q3LDa9w== From: Arnd Bergmann To: linux-kernel@vger.kernel.org Cc: Arnd Bergmann , Vineet Gupta , Russell King , Neil Armstrong , Linus Walleij , Catalin Marinas , Will Deacon , Guo Ren , Brian Cain , Geert Uytterhoeven , Michal Simek , Thomas Bogendoerfer , Dinh Nguyen , Stafford Horne , Helge Deller , Michael Ellerman , Christophe Leroy , Paul Walmsley , Palmer Dabbelt , Rich Felker , John Paul Adrian Glaubitz , "David S. Miller" , Max Filippov , Christoph Hellwig , Robin Murphy , Lad Prabhakar , Conor Dooley , linux-snps-arc@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-oxnas@groups.io, linux-csky@vger.kernel.org, linux-hexagon@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-mips@vger.kernel.org, linux-openrisc@vger.kernel.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org, linux-xtensa@linux-xtensa.org Subject: [PATCH 08/21] riscv: dma-mapping: only invalidate after DMA, not flush Date: Mon, 27 Mar 2023 14:13:04 +0200 Message-Id: <20230327121317.4081816-9-arnd@kernel.org> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230327121317.4081816-1-arnd@kernel.org> References: <20230327121317.4081816-1-arnd@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org From: Arnd Bergmann No other architecture intentionally writes back dirty cache lines into a buffer that a device has just finished writing into. If the cache is clean, this has no effect at all, but if a cacheline in the buffer has actually been written by the CPU, there is a drive bug that is likely made worse by overwriting that buffer. Signed-off-by: Arnd Bergmann Reviewed-by: Conor Dooley Reviewed-by: Lad Prabhakar Acked-by: Palmer Dabbelt --- arch/riscv/mm/dma-noncoherent.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/riscv/mm/dma-noncoherent.c b/arch/riscv/mm/dma-noncoherent.c index d919efab6eba..640f4c496d26 100644 --- a/arch/riscv/mm/dma-noncoherent.c +++ b/arch/riscv/mm/dma-noncoherent.c @@ -42,7 +42,7 @@ void arch_sync_dma_for_cpu(phys_addr_t paddr, size_t size, break; case DMA_FROM_DEVICE: case DMA_BIDIRECTIONAL: - ALT_CMO_OP(flush, vaddr, size, riscv_cbom_block_size); + ALT_CMO_OP(inval, vaddr, size, riscv_cbom_block_size); break; default: break;