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From: Thierry Reding <thierry.reding@gmail.com>
To: Thierry Reding <thierry.reding@gmail.com>
Cc: linux-tegra@vger.kernel.org, Dmitry Osipenko <digetx@gmail.com>,
	dri-devel@lists.freedesktop.org,
	Mikko Perttunen <mperttunen@nvidia.com>
Subject: [PATCH v3 08/16] gpu: host1x: Use correct semantics for HOST1X_CHANNEL_DMAEND
Date: Fri,  1 Feb 2019 14:28:29 +0100	[thread overview]
Message-ID: <20190201132837.12327-9-thierry.reding@gmail.com> (raw)
In-Reply-To: <20190201132837.12327-1-thierry.reding@gmail.com>

From: Thierry Reding <treding@nvidia.com>

The HOST1X_CHANNEL_DMAEND is an offset relative to the value written to
the HOST1X_CHANNEL_DMASTART register, but it is currently treated as an
absolute address. This can cause SMMU faults if the CDMA fetches past a
pushbuffer's IOMMU mapping.

Properly setting the DMAEND prevents the CDMA from fetching beyond that
address and avoid such issues. This is currently not observed because a
whole (almost) page of essentially scratch space absorbs any excessive
prefetching by CDMA. However, changing the number of slots in the push
buffer can trigger these SMMU faults.

Signed-off-by: Thierry Reding <treding@nvidia.com>
---
 drivers/gpu/host1x/hw/cdma_hw.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/host1x/hw/cdma_hw.c b/drivers/gpu/host1x/hw/cdma_hw.c
index 485aef5761af..a24c090ac96f 100644
--- a/drivers/gpu/host1x/hw/cdma_hw.c
+++ b/drivers/gpu/host1x/hw/cdma_hw.c
@@ -75,7 +75,7 @@ static void cdma_start(struct host1x_cdma *cdma)
 
 	cdma->last_pos = cdma->push_buffer.pos;
 	start = cdma->push_buffer.dma;
-	end = start + cdma->push_buffer.size + 4;
+	end = cdma->push_buffer.size + 4;
 
 	host1x_ch_writel(ch, HOST1X_CHANNEL_DMACTRL_DMASTOP,
 			 HOST1X_CHANNEL_DMACTRL);
@@ -126,7 +126,7 @@ static void cdma_timeout_restart(struct host1x_cdma *cdma, u32 getptr)
 			 HOST1X_CHANNEL_DMACTRL);
 
 	start = cdma->push_buffer.dma;
-	end = start + cdma->push_buffer.size + 4;
+	end = cdma->push_buffer.size + 4;
 
 	/* set base, end pointer (all of memory) */
 	host1x_ch_writel(ch, lower_32_bits(start), HOST1X_CHANNEL_DMASTART);
-- 
2.19.1

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  parent reply	other threads:[~2019-02-01 13:28 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-02-01 13:28 [PATCH v3 00/16] drm/tegra: Fix IOVA space on Tegra186 and later Thierry Reding
2019-02-01 13:28 ` [PATCH v3 01/16] gpu: host1x: Set up stream ID table Thierry Reding
2019-02-01 13:28 ` [PATCH v3 02/16] gpu: host1x: Program the channel stream ID Thierry Reding
2019-02-01 13:28 ` [PATCH v3 03/16] gpu: host1x: Introduce support for wide opcodes Thierry Reding
2019-02-01 13:28 ` [PATCH v3 04/16] gpu: host1x: Support 40-bit addressing Thierry Reding
2019-02-01 13:28 ` [PATCH v3 05/16] gpu: host1x: Use direct DMA with IOMMU API usage Thierry Reding
2019-02-01 14:46   ` Dmitry Osipenko
2019-02-01 13:28 ` [PATCH v3 06/16] gpu: host1x: Restrict IOVA space to DMA mask Thierry Reding
2019-02-01 14:47   ` Dmitry Osipenko
2019-02-01 13:28 ` [PATCH v3 07/16] gpu: host1x: Support 40-bit addressing on Tegra186 Thierry Reding
2019-02-01 13:28 ` Thierry Reding [this message]
2019-02-01 13:37   ` [PATCH v3 08/16] gpu: host1x: Use correct semantics for HOST1X_CHANNEL_DMAEND Dmitry Osipenko
2019-02-01 13:41     ` Thierry Reding
2019-02-01 13:48       ` Dmitry Osipenko
2019-02-01 14:10         ` Thierry Reding
2019-02-01 14:40           ` Dmitry Osipenko
2019-02-01 14:47   ` Dmitry Osipenko
2019-02-01 13:28 ` [PATCH v3 09/16] gpu: host1x: Optimize CDMA push buffer memory usage Thierry Reding
2019-02-01 14:48   ` Dmitry Osipenko
2019-02-01 13:28 ` [PATCH v3 10/16] drm/tegra: Store parent pointer in Tegra DRM clients Thierry Reding
2019-02-01 14:48   ` Dmitry Osipenko
2019-02-01 13:28 ` [PATCH v3 11/16] drm/tegra: vic: Load firmware on demand Thierry Reding
2019-02-01 13:28 ` [PATCH v3 12/16] drm/tegra: Setup shared IOMMU domain after initialization Thierry Reding
2019-02-01 14:48   ` Dmitry Osipenko
2019-02-01 13:28 ` [PATCH v3 13/16] drm/tegra: Restrict IOVA space to DMA mask Thierry Reding
2019-02-01 14:49   ` Dmitry Osipenko
2019-02-01 13:28 ` [PATCH v3 14/16] drm/tegra: vic: Do not clear driver data Thierry Reding
2019-02-01 13:28 ` [PATCH v3 15/16] drm/tegra: vic: Support stream ID register programming Thierry Reding
2019-02-01 13:28 ` [PATCH v3 16/16] arm64: tegra: Enable SMMU for VIC on Tegra186 Thierry Reding
2019-02-01 14:46 ` [PATCH v3 00/16] drm/tegra: Fix IOVA space on Tegra186 and later Dmitry Osipenko

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