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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 49E07C43334 for ; Mon, 20 Jun 2022 08:18:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239862AbiFTISi (ORCPT ); Mon, 20 Jun 2022 04:18:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36876 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239858AbiFTISg (ORCPT ); Mon, 20 Jun 2022 04:18:36 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2F73D11A1F for ; Mon, 20 Jun 2022 01:18:34 -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 dfw.source.kernel.org (Postfix) with ESMTPS id 52E81612A0 for ; Mon, 20 Jun 2022 08:18:34 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4D9CFC3411B; Mon, 20 Jun 2022 08:18:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1655713113; bh=+C8DL/vM9Po+r7qqrnftap4ZHGbQKAuitpk9S92j6ww=; h=Subject:To:Cc:From:Date:From; b=OfwWyChAo/da6tow4dPl+vcIBg7K3dQVQoeCFwAM/G5970iWAORPH1WduJegpW/mw Md7BTgBfVxFMYCyGJIMXnP0LIoJJ1QZKKUiyXiO61C69HKXGRR3+0crRiW6h+UaYQd C4e0Wux8mqqKMhJzHDTBxzYxtnO3Ys/7r/YG/ZkY= Subject: FAILED: patch "[PATCH] arm64: mm: Don't invalidate FROM_DEVICE buffers at start of" failed to apply to 5.4-stable tree To: will@kernel.org, ardb@kernel.org, catalin.marinas@arm.com, hch@lst.de, linux@armlinux.org.uk, robin.murphy@arm.com, stable@vger.kernel.org Cc: From: Date: Mon, 20 Jun 2022 10:18:20 +0200 Message-ID: <1655713100183167@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From c50f11c6196f45c92ca48b16a5071615d4ae0572 Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Fri, 10 Jun 2022 16:12:27 +0100 Subject: [PATCH] arm64: mm: Don't invalidate FROM_DEVICE buffers at start of DMA transfer Invalidating the buffer memory in arch_sync_dma_for_device() for FROM_DEVICE transfers When using the streaming DMA API to map a buffer prior to inbound non-coherent DMA (i.e. DMA_FROM_DEVICE), we invalidate any dirty CPU cachelines so that they will not be written back during the transfer and corrupt the buffer contents written by the DMA. This, however, poses two potential problems: (1) If the DMA transfer does not write to every byte in the buffer, then the unwritten bytes will contain stale data once the transfer has completed. (2) If the buffer has a virtual alias in userspace, then stale data may be visible via this alias during the period between performing the cache invalidation and the DMA writes landing in memory. Address both of these issues by cleaning (aka writing-back) the dirty lines in arch_sync_dma_for_device(DMA_FROM_DEVICE) instead of discarding them using invalidation. Cc: Ard Biesheuvel Cc: Christoph Hellwig Cc: Robin Murphy Cc: Russell King Cc: Link: https://lore.kernel.org/r/20220606152150.GA31568@willie-the-truck Signed-off-by: Will Deacon Reviewed-by: Ard Biesheuvel Link: https://lore.kernel.org/r/20220610151228.4562-2-will@kernel.org Signed-off-by: Catalin Marinas diff --git a/arch/arm64/mm/cache.S b/arch/arm64/mm/cache.S index 0ea6cc25dc66..21c907987080 100644 --- a/arch/arm64/mm/cache.S +++ b/arch/arm64/mm/cache.S @@ -218,8 +218,6 @@ SYM_FUNC_ALIAS(__dma_flush_area, __pi___dma_flush_area) */ SYM_FUNC_START(__pi___dma_map_area) add x1, x0, x1 - cmp w2, #DMA_FROM_DEVICE - b.eq __pi_dcache_inval_poc b __pi_dcache_clean_poc SYM_FUNC_END(__pi___dma_map_area) SYM_FUNC_ALIAS(__dma_map_area, __pi___dma_map_area)