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=-6.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 8E9C8C433FF for ; Sat, 3 Aug 2019 00:14:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5E4B62086A for ; Sat, 3 Aug 2019 00:14:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="MLkWEGvk" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728388AbfHCAOr (ORCPT ); Fri, 2 Aug 2019 20:14:47 -0400 Received: from mail-io1-f68.google.com ([209.85.166.68]:39862 "EHLO mail-io1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728301AbfHCAOr (ORCPT ); Fri, 2 Aug 2019 20:14:47 -0400 Received: by mail-io1-f68.google.com with SMTP id f4so155909155ioh.6 for ; Fri, 02 Aug 2019 17:14:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=h4x/c6aFCerGwW46+jAJx/0xkBWsbbCj8p2s7VTuzx8=; b=MLkWEGvkkIkdnTVe/Yq9GekUC+t7Ci3fj98xN5HfkXiOvm/MMg784R24yCjHSu8K0h AW6wNE43CTPQ3HnsY09vnm7ebuGXirzQWPSNRbN6TDV+yMRx6wt4mBurzmx7Lfu7xfWd wvOc91VHRIKLo1B9aqILfav2Bz8i3r18qHvWo= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=h4x/c6aFCerGwW46+jAJx/0xkBWsbbCj8p2s7VTuzx8=; b=J5pBJbChdYBr/azeeCAxaZqhllYJVsThnYiIt4M+rBMcf265XAv+sMeuAQIYETL+SE vk5LITy487t+ZhIuEKOJs2yoTs1MZ098syh6J9dhSiWFnmaklVbkIoZpBQ0thOsalRlc 0GxX3g7PvTpyQod/7Y1m5TAdtOEz3vC+J15qR/I5lmbXQD/3izxlP6kOxrqbzrDZQQXw kpCjeUwlFBAsUyzQKeYBDw5hV85snjCHz1FgDF2GxxAKWRzrBdjJLtTUPcljO9Hez6SE wROxKPRZtqCHRwm4wguEXtmtOTvKkLp2PrOStHv8tDJ0FIB9AV7bCvEDCXOEcamYVj0z NImw== X-Gm-Message-State: APjAAAUK2QqkcnXyuvxdh/dsUnz3mwjKo2v/7YsWhwb/E0oQ2q3M9mjt B5H/RNnHzG5OC8p+9tu1QI2IMDIf2hpFdvuWknereA== X-Google-Smtp-Source: APXvYqzf+8HF1jNb9DEf6l4Ve9OqBkgZcoiA7Q7ZK26p9D3udPa2BQT1369JwNyXg+EZvobWAJFoHF0bH17R4/EaURY= X-Received: by 2002:a02:c916:: with SMTP id t22mr3605894jao.24.1564791286556; Fri, 02 Aug 2019 17:14:46 -0700 (PDT) MIME-Version: 1.0 References: <20190802131951.11600-1-sashal@kernel.org> <20190802131951.11600-42-sashal@kernel.org> In-Reply-To: <20190802131951.11600-42-sashal@kernel.org> From: Rob Clark Date: Fri, 2 Aug 2019 17:14:35 -0700 Message-ID: Subject: Re: [PATCH AUTOSEL 5.2 42/76] drm/msm: stop abusing dma_map/unmap for cache To: Sasha Levin Cc: LKML , stable@vger.kernel.org, Stephen Boyd , Stephen Boyd , Jordan Crouse , Sean Paul , linux-arm-msm , dri-devel , freedreno Content-Type: text/plain; charset="UTF-8" Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org Hi Sasha, It's probably best *not* to backport this patch.. drm/msm abuses the DMA API in a way that it is not intended be used, to work around the lack of cache sync API exported to kernel modules on arm/arm64. I couldn't really guarantee that this patch does the right thing on older versions of DMA API, so best to leave things as they were. BR, -R On Fri, Aug 2, 2019 at 6:21 AM Sasha Levin wrote: > > From: Rob Clark > > [ Upstream commit 0036bc73ccbe7e600a3468bf8e8879b122252274 ] > > Recently splats like this started showing up: > > WARNING: CPU: 4 PID: 251 at drivers/iommu/dma-iommu.c:451 __iommu_dma_unmap+0xb8/0xc0 > Modules linked in: ath10k_snoc ath10k_core fuse msm ath mac80211 uvcvideo cfg80211 videobuf2_vmalloc videobuf2_memops vide > CPU: 4 PID: 251 Comm: kworker/u16:4 Tainted: G W 5.2.0-rc5-next-20190619+ #2317 > Hardware name: LENOVO 81JL/LNVNB161216, BIOS 9UCN23WW(V1.06) 10/25/2018 > Workqueue: msm msm_gem_free_work [msm] > pstate: 80c00005 (Nzcv daif +PAN +UAO) > pc : __iommu_dma_unmap+0xb8/0xc0 > lr : __iommu_dma_unmap+0x54/0xc0 > sp : ffff0000119abce0 > x29: ffff0000119abce0 x28: 0000000000000000 > x27: ffff8001f9946648 x26: ffff8001ec271068 > x25: 0000000000000000 x24: ffff8001ea3580a8 > x23: ffff8001f95ba010 x22: ffff80018e83ba88 > x21: ffff8001e548f000 x20: fffffffffffff000 > x19: 0000000000001000 x18: 00000000c00001fe > x17: 0000000000000000 x16: 0000000000000000 > x15: ffff000015b70068 x14: 0000000000000005 > x13: 0003142cc1be1768 x12: 0000000000000001 > x11: ffff8001f6de9100 x10: 0000000000000009 > x9 : ffff000015b78000 x8 : 0000000000000000 > x7 : 0000000000000001 x6 : fffffffffffff000 > x5 : 0000000000000fff x4 : ffff00001065dbc8 > x3 : 000000000000000d x2 : 0000000000001000 > x1 : fffffffffffff000 x0 : 0000000000000000 > Call trace: > __iommu_dma_unmap+0xb8/0xc0 > iommu_dma_unmap_sg+0x98/0xb8 > put_pages+0x5c/0xf0 [msm] > msm_gem_free_work+0x10c/0x150 [msm] > process_one_work+0x1e0/0x330 > worker_thread+0x40/0x438 > kthread+0x12c/0x130 > ret_from_fork+0x10/0x18 > ---[ end trace afc0dc5ab81a06bf ]--- > > Not quite sure what triggered that, but we really shouldn't be abusing > dma_{map,unmap}_sg() for cache maint. > > Cc: Stephen Boyd > Tested-by: Stephen Boyd > Reviewed-by: Jordan Crouse > Signed-off-by: Rob Clark > Signed-off-by: Sean Paul > Link: https://patchwork.freedesktop.org/patch/msgid/20190630124735.27786-1-robdclark@gmail.com > Signed-off-by: Sasha Levin > --- > drivers/gpu/drm/msm/msm_gem.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/msm/msm_gem.c b/drivers/gpu/drm/msm/msm_gem.c > index 49a019939ccdc..a3b5fe1a13944 100644 > --- a/drivers/gpu/drm/msm/msm_gem.c > +++ b/drivers/gpu/drm/msm/msm_gem.c > @@ -97,7 +97,7 @@ static struct page **get_pages(struct drm_gem_object *obj) > * because display controller, GPU, etc. are not coherent: > */ > if (msm_obj->flags & (MSM_BO_WC|MSM_BO_UNCACHED)) > - dma_map_sg(dev->dev, msm_obj->sgt->sgl, > + dma_sync_sg_for_device(dev->dev, msm_obj->sgt->sgl, > msm_obj->sgt->nents, DMA_BIDIRECTIONAL); > } > > @@ -127,7 +127,7 @@ static void put_pages(struct drm_gem_object *obj) > * GPU, etc. are not coherent: > */ > if (msm_obj->flags & (MSM_BO_WC|MSM_BO_UNCACHED)) > - dma_unmap_sg(obj->dev->dev, msm_obj->sgt->sgl, > + dma_sync_sg_for_cpu(obj->dev->dev, msm_obj->sgt->sgl, > msm_obj->sgt->nents, > DMA_BIDIRECTIONAL); > > -- > 2.20.1 >