Hi all,
this series fixes a rather gross layering violation in videobuf2, which
pokes into arm DMA mapping internals to get a DMA address for memory that
does not have a page structure, and to do so fixes up the dma_map_resource
implementation to not provide a somewhat dangerous default and improve
the error handling.
Changes since v1:
- don't apply bus offsets in dma_direct_map_resource
Instead provide a proper implementation in the direct mapping code, and
also wire it up for arm and powerpc, leaving an error return for all the
IOMMU or virtual mapping instances for which we'd have to wire up an
actual implementation
Signed-off-by: Christoph Hellwig <[email protected]>
---
arch/arm/mm/dma-mapping.c | 2 ++
arch/powerpc/kernel/dma-swiotlb.c | 1 +
arch/powerpc/kernel/dma.c | 1 +
include/linux/dma-mapping.h | 12 +++++++-----
kernel/dma/direct.c | 14 ++++++++++++++
5 files changed, 25 insertions(+), 5 deletions(-)
diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index f1e2922e447c..3c8534904209 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -188,6 +188,7 @@ const struct dma_map_ops arm_dma_ops = {
.unmap_page = arm_dma_unmap_page,
.map_sg = arm_dma_map_sg,
.unmap_sg = arm_dma_unmap_sg,
+ .map_resource = dma_direct_map_resource,
.sync_single_for_cpu = arm_dma_sync_single_for_cpu,
.sync_single_for_device = arm_dma_sync_single_for_device,
.sync_sg_for_cpu = arm_dma_sync_sg_for_cpu,
@@ -211,6 +212,7 @@ const struct dma_map_ops arm_coherent_dma_ops = {
.get_sgtable = arm_dma_get_sgtable,
.map_page = arm_coherent_dma_map_page,
.map_sg = arm_dma_map_sg,
+ .map_resource = dma_direct_map_resource,
.dma_supported = arm_dma_supported,
};
EXPORT_SYMBOL(arm_coherent_dma_ops);
diff --git a/arch/powerpc/kernel/dma-swiotlb.c b/arch/powerpc/kernel/dma-swiotlb.c
index 7d5fc9751622..fbb2506a414e 100644
--- a/arch/powerpc/kernel/dma-swiotlb.c
+++ b/arch/powerpc/kernel/dma-swiotlb.c
@@ -55,6 +55,7 @@ const struct dma_map_ops powerpc_swiotlb_dma_ops = {
.dma_supported = swiotlb_dma_supported,
.map_page = dma_direct_map_page,
.unmap_page = dma_direct_unmap_page,
+ .map_resource = dma_direct_map_resource,
.sync_single_for_cpu = dma_direct_sync_single_for_cpu,
.sync_single_for_device = dma_direct_sync_single_for_device,
.sync_sg_for_cpu = dma_direct_sync_sg_for_cpu,
diff --git a/arch/powerpc/kernel/dma.c b/arch/powerpc/kernel/dma.c
index b1903ebb2e9c..258b9e8ebb99 100644
--- a/arch/powerpc/kernel/dma.c
+++ b/arch/powerpc/kernel/dma.c
@@ -273,6 +273,7 @@ const struct dma_map_ops dma_nommu_ops = {
.dma_supported = dma_nommu_dma_supported,
.map_page = dma_nommu_map_page,
.unmap_page = dma_nommu_unmap_page,
+ .map_resource = dma_direct_map_resource,
.get_required_mask = dma_nommu_get_required_mask,
#ifdef CONFIG_NOT_COHERENT_CACHE
.sync_single_for_cpu = dma_nommu_sync_single,
diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index f6ded992c183..9842085e6774 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -208,6 +208,8 @@ dma_addr_t dma_direct_map_page(struct device *dev, struct page *page,
unsigned long attrs);
int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl, int nents,
enum dma_data_direction dir, unsigned long attrs);
+dma_addr_t dma_direct_map_resource(struct device *dev, phys_addr_t paddr,
+ size_t size, enum dma_data_direction dir, unsigned long attrs);
#if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE) || \
defined(CONFIG_SWIOTLB)
@@ -346,19 +348,19 @@ static inline dma_addr_t dma_map_resource(struct device *dev,
unsigned long attrs)
{
const struct dma_map_ops *ops = get_dma_ops(dev);
- dma_addr_t addr;
+ dma_addr_t addr = DMA_MAPPING_ERROR;
BUG_ON(!valid_dma_direction(dir));
/* Don't allow RAM to be mapped */
BUG_ON(pfn_valid(PHYS_PFN(phys_addr)));
- addr = phys_addr;
- if (ops && ops->map_resource)
+ if (dma_is_direct(ops))
+ addr = dma_direct_map_resource(dev, phys_addr, size, dir, attrs);
+ else if (ops->map_resource)
addr = ops->map_resource(dev, phys_addr, size, dir, attrs);
debug_dma_map_resource(dev, phys_addr, size, dir, addr);
-
return addr;
}
@@ -369,7 +371,7 @@ static inline void dma_unmap_resource(struct device *dev, dma_addr_t addr,
const struct dma_map_ops *ops = get_dma_ops(dev);
BUG_ON(!valid_dma_direction(dir));
- if (ops && ops->unmap_resource)
+ if (!dma_is_direct(ops) && ops->unmap_resource)
ops->unmap_resource(dev, addr, size, dir, attrs);
debug_dma_unmap_resource(dev, addr, size, dir);
}
diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 355d16acee6d..25bd19974223 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -356,6 +356,20 @@ int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl, int nents,
}
EXPORT_SYMBOL(dma_direct_map_sg);
+dma_addr_t dma_direct_map_resource(struct device *dev, phys_addr_t paddr,
+ size_t size, enum dma_data_direction dir, unsigned long attrs)
+{
+ dma_addr_t dma_addr = paddr;
+
+ if (unlikely(!dma_direct_possible(dev, dma_addr, size))) {
+ report_addr(dev, dma_addr, size);
+ return DMA_MAPPING_ERROR;
+ }
+
+ return dma_addr;
+}
+EXPORT_SYMBOL(dma_direct_map_resource);
+
/*
* Because 32-bit DMA masks are so common we expect every architecture to be
* able to satisfy them - either by not supporting more physical memory, or by
--
2.20.1
vb2_dc_get_userptr pokes into arm direct mapping details to get the
resemblance of a dma address for a a physical address that does is
not backed by a page struct. Not only is this not portable to other
architectures with dma direct mapping offsets, but also not to uses
of IOMMUs of any kind. Switch to the proper dma_map_resource /
dma_unmap_resource interface instead.
Signed-off-by: Christoph Hellwig <[email protected]>
Acked-by: Mauro Carvalho Chehab <[email protected]>
---
.../common/videobuf2/videobuf2-dma-contig.c | 41 ++++---------------
1 file changed, 9 insertions(+), 32 deletions(-)
diff --git a/drivers/media/common/videobuf2/videobuf2-dma-contig.c b/drivers/media/common/videobuf2/videobuf2-dma-contig.c
index aff0ab7bf83d..82389aead6ed 100644
--- a/drivers/media/common/videobuf2/videobuf2-dma-contig.c
+++ b/drivers/media/common/videobuf2/videobuf2-dma-contig.c
@@ -439,42 +439,14 @@ static void vb2_dc_put_userptr(void *buf_priv)
set_page_dirty_lock(pages[i]);
sg_free_table(sgt);
kfree(sgt);
+ } else {
+ dma_unmap_resource(buf->dev, buf->dma_addr, buf->size,
+ buf->dma_dir, 0);
}
vb2_destroy_framevec(buf->vec);
kfree(buf);
}
-/*
- * For some kind of reserved memory there might be no struct page available,
- * so all that can be done to support such 'pages' is to try to convert
- * pfn to dma address or at the last resort just assume that
- * dma address == physical address (like it has been assumed in earlier version
- * of videobuf2-dma-contig
- */
-
-#ifdef __arch_pfn_to_dma
-static inline dma_addr_t vb2_dc_pfn_to_dma(struct device *dev, unsigned long pfn)
-{
- return (dma_addr_t)__arch_pfn_to_dma(dev, pfn);
-}
-#elif defined(__pfn_to_bus)
-static inline dma_addr_t vb2_dc_pfn_to_dma(struct device *dev, unsigned long pfn)
-{
- return (dma_addr_t)__pfn_to_bus(pfn);
-}
-#elif defined(__pfn_to_phys)
-static inline dma_addr_t vb2_dc_pfn_to_dma(struct device *dev, unsigned long pfn)
-{
- return (dma_addr_t)__pfn_to_phys(pfn);
-}
-#else
-static inline dma_addr_t vb2_dc_pfn_to_dma(struct device *dev, unsigned long pfn)
-{
- /* really, we cannot do anything better at this point */
- return (dma_addr_t)(pfn) << PAGE_SHIFT;
-}
-#endif
-
static void *vb2_dc_get_userptr(struct device *dev, unsigned long vaddr,
unsigned long size, enum dma_data_direction dma_dir)
{
@@ -528,7 +500,12 @@ static void *vb2_dc_get_userptr(struct device *dev, unsigned long vaddr,
for (i = 1; i < n_pages; i++)
if (nums[i-1] + 1 != nums[i])
goto fail_pfnvec;
- buf->dma_addr = vb2_dc_pfn_to_dma(buf->dev, nums[0]);
+ buf->dma_addr = dma_map_resource(buf->dev,
+ __pfn_to_phys(nums[0]), size, buf->dma_dir, 0);
+ if (dma_mapping_error(buf->dev, buf->dma_addr)) {
+ ret = -ENOMEM;
+ goto fail_pfnvec;
+ }
goto out;
}
--
2.20.1
Use WARN_ON_ONCE to print a stack trace and return a proper error
code instead.
Signed-off-by: Christoph Hellwig <[email protected]>
Reviewed-by: Robin Murphy <[email protected]>
---
include/linux/dma-mapping.h | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index 9842085e6774..b904d55247ab 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -353,7 +353,8 @@ static inline dma_addr_t dma_map_resource(struct device *dev,
BUG_ON(!valid_dma_direction(dir));
/* Don't allow RAM to be mapped */
- BUG_ON(pfn_valid(PHYS_PFN(phys_addr)));
+ if (WARN_ON_ONCE(pfn_valid(PHYS_PFN(phys_addr))))
+ return DMA_MAPPING_ERROR;
if (dma_is_direct(ops))
addr = dma_direct_map_resource(dev, phys_addr, size, dir, attrs);
--
2.20.1
Hi All,
On 2019-01-18 12:37, Christoph Hellwig wrote:
> Hi all,
>
> this series fixes a rather gross layering violation in videobuf2, which
> pokes into arm DMA mapping internals to get a DMA address for memory that
> does not have a page structure, and to do so fixes up the dma_map_resource
> implementation to not provide a somewhat dangerous default and improve
> the error handling.
>
> Changes since v1:
> - don't apply bus offsets in dma_direct_map_resource
Works fine on older Exynos based boards with IOMMU and CMA disabled.
Tested-by: Marek Szyprowski <[email protected]>
Best regards
--
Marek Szyprowski, PhD
Samsung R&D Institute Poland
On Fri, Feb 01, 2019 at 08:05:21AM +0100, Marek Szyprowski wrote:
> Works fine on older Exynos based boards with IOMMU and CMA disabled.
>
> Tested-by: Marek Szyprowski <[email protected]>
Thanks. I've merged the Ń•eries into the dma-mapping tree, and I've
also made a stable branch available at:
git://git.infradead.org/users/hch/dma-mapping.git videobuf-map-resource
in case it needs to be pulled into the media tree.