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iommu: msm: validate subsequent lazy map arguments

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Validate that attempts to lazy map a buffer, that is already
lazy mapped, request the same number of elements, direction
and dma mapping attributes as the original mapping.

Change-Id: I6094cd6281a22525aa9971f1c5684f423be08580
Signed-off-by: Liam Mark <lmark@codeaurora.org>
This commit is contained in:
Liam Mark
2017-11-30 16:59:25 -08:00
parent 54d765eb22
commit a67eb07a0f
2 changed files with 58 additions and 21 deletions
Download Patch File Download Diff File Expand all files Collapse all files

62
drivers/iommu/msm_dma_iommu_mapping.c
View File

@@ -1,4 +1,4 @@
/* Copyright (c) 2015-2016, The Linux Foundation. All rights reserved.
/* Copyright (c) 2015-2017, The Linux Foundation. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 and
@@ -27,9 +27,11 @@
* @dev - Device this is mapped to. Used as key
* @sgl - The scatterlist for this mapping
* @nents - Number of entries in sgl
* @dir - The direction for the unmap.
* @dir - The direction for the map.
* @meta - Backpointer to the meta this guy belongs to.
* @ref - for reference counting this mapping
* @map_attrs - dma mapping attributes
* @buf_start_addr - address of start of buffer
*
* Represents a mapping of one dma_buf buffer to a particular device
* and address range. There may exist other mappings of this buffer in
@@ -44,6 +46,8 @@ struct msm_iommu_map {
enum dma_data_direction dir;
struct msm_iommu_meta *meta;
struct kref ref;
unsigned long map_attrs;
dma_addr_t buf_start_addr;
};
struct msm_iommu_meta {
@@ -199,21 +203,43 @@ static inline int __msm_dma_map_sg(struct device *dev, struct scatterlist *sg,
iommu_map->sgl.dma_address = sg->dma_address;
iommu_map->sgl.dma_length = sg->dma_length;
iommu_map->dev = dev;
iommu_map->dir = dir;
iommu_map->nents = nents;
iommu_map->map_attrs = attrs;
iommu_map->buf_start_addr = sg_phys(sg);
msm_iommu_add(iommu_meta, iommu_map);
} else {
sg->dma_address = iommu_map->sgl.dma_address;
sg->dma_length = iommu_map->sgl.dma_length;
if (nents == iommu_map->nents &&
dir == iommu_map->dir &&
attrs == iommu_map->map_attrs &&
sg_phys(sg) == iommu_map->buf_start_addr) {
sg->dma_address = iommu_map->sgl.dma_address;
sg->dma_length = iommu_map->sgl.dma_length;
kref_get(&iommu_map->ref);
if (is_device_dma_coherent(dev))
/*
* Ensure all outstanding changes for coherent
* buffers are applied to the cache before any
* DMA occurs.
*/
dmb(ish);
ret = nents;
kref_get(&iommu_map->ref);
if (is_device_dma_coherent(dev))
/*
* Ensure all outstanding changes for coherent
* buffers are applied to the cache before any
* DMA occurs.
*/
dmb(ish);
ret = nents;
} else {
bool start_diff = (sg_phys(sg) !=
iommu_map->buf_start_addr);
dev_err(dev, "lazy map request differs:\n"
"req dir:%d, original dir:%d\n"
"req nents:%d, original nents:%d\n"
"req map attrs:%lu, original map attrs:%lu\n"
"req buffer start address differs:%d\n",
dir, iommu_map->dir, nents,
iommu_map->nents, attrs, iommu_map->map_attrs,
start_diff);
ret = -EINVAL;
}
}
mutex_unlock(&iommu_meta->lock);
return ret;
@@ -321,13 +347,9 @@ void msm_dma_unmap_sg(struct device *dev, struct scatterlist *sgl, int nents,
goto out;
}
/*
* Save direction for later use when we actually unmap.
* Not used right now but in the future if we go to coherent mapping
* API we might want to call the appropriate API when client asks
* to unmap
*/
iommu_map->dir = dir;
if (dir != iommu_map->dir)
WARN(1, "%s: (%pK) dir:%d differs from original dir:%d\n",
__func__, dma_buf, dir, iommu_map->dir);
kref_put(&iommu_map->ref, msm_iommu_map_release);
mutex_unlock(&meta->lock);

17
include/linux/msm_dma_iommu_mapping.h
View File

@@ -1,4 +1,4 @@
/* Copyright (c) 2015-2016, The Linux Foundation. All rights reserved.
/* Copyright (c) 2015-2017, The Linux Foundation. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 and
@@ -28,6 +28,21 @@ int msm_dma_map_sg_attrs(struct device *dev, struct scatterlist *sg, int nents,
enum dma_data_direction dir, struct dma_buf *dma_buf,
unsigned long attrs);
/*
* This function takes an extra reference to the dma_buf.
* What this means is that calling msm_dma_unmap_sg will not result in buffer's
* iommu mapping being removed, which means that subsequent calls to lazy map
* will simply re-use the existing iommu mapping.
* The iommu unmapping of the buffer will occur when the ION buffer is
* destroyed.
* Using lazy mapping can provide a performance benefit because subsequent
* mappings are faster.
*
* The limitation of using this API are that all subsequent iommu mappings
* must be the same as the original mapping, ie they must map the same part of
* the buffer with the same dma data direction. Also there can't be multiple
* mappings of different parts of the buffer.
*/
static inline int msm_dma_map_sg_lazy(struct device *dev,
struct scatterlist *sg, int nents,
enum dma_data_direction dir,