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authorRobin Murphy <Robin.Murphy@arm.com>2015-09-17 17:42:16 +0100
committerWill Deacon <will.deacon@arm.com>2015-09-22 17:35:33 +0100
commitffcb6d1686ceb4a6b50776fb2597ab0e4dd79040 (patch)
tree55f734b2d6a0ee79b0c0e5ede21e7a94feadd0c4
parent6ff33f3902c3b1c5d0db6b1e2c70b6d76fba357f (diff)
iommu/io-pgtable-arm: Don't use dma_to_phys()
In checking whether DMA addresses differ from physical addresses, using dma_to_phys() is actually the wrong thing to do, since it may hide any DMA offset, which is precisely one of the things we are checking for. Simply casting between the two address types, whilst ugly, is in fact the appropriate course of action. Further care (and ugliness) is also necessary in the comparison to avoid truncation if phys_addr_t and dma_addr_t differ in size. We can also reject any device with a fixed DMA offset up-front at page table creation, leaving the allocation-time check for the more subtle cases like bounce buffering due to an incorrect DMA mask. Furthermore, we can then fix the hackish KConfig dependency so that architectures without a dma_to_phys() implementation may still COMPILE_TEST (or even use!) the code. The true dependency is on the DMA API, so use the appropriate symbol for that. Signed-off-by: Robin Murphy <robin.murphy@arm.com> [will: folded in selftest fix from Yong Wu] Signed-off-by: Will Deacon <will.deacon@arm.com>
-rw-r--r--drivers/iommu/Kconfig3
-rw-r--r--drivers/iommu/io-pgtable-arm.c24
2 files changed, 14 insertions, 13 deletions
diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
index 4664c2a96c67..3dc1bcb0d01d 100644
--- a/drivers/iommu/Kconfig
+++ b/drivers/iommu/Kconfig
@@ -23,8 +23,7 @@ config IOMMU_IO_PGTABLE
config IOMMU_IO_PGTABLE_LPAE
bool "ARMv7/v8 Long Descriptor Format"
select IOMMU_IO_PGTABLE
- # SWIOTLB guarantees a dma_to_phys() implementation
- depends on ARM || ARM64 || (COMPILE_TEST && SWIOTLB)
+ depends on HAS_DMA && (ARM || ARM64 || COMPILE_TEST)
help
Enable support for the ARM long descriptor pagetable format.
This allocator supports 4K/2M/1G, 16K/32M and 64K/512M page
diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c
index 73c07482f487..7df97777662d 100644
--- a/drivers/iommu/io-pgtable-arm.c
+++ b/drivers/iommu/io-pgtable-arm.c
@@ -202,9 +202,9 @@ typedef u64 arm_lpae_iopte;
static bool selftest_running = false;
-static dma_addr_t __arm_lpae_dma_addr(struct device *dev, void *pages)
+static dma_addr_t __arm_lpae_dma_addr(void *pages)
{
- return phys_to_dma(dev, virt_to_phys(pages));
+ return (dma_addr_t)virt_to_phys(pages);
}
static void *__arm_lpae_alloc_pages(size_t size, gfp_t gfp,
@@ -223,10 +223,10 @@ static void *__arm_lpae_alloc_pages(size_t size, gfp_t gfp,
goto out_free;
/*
* We depend on the IOMMU being able to work with any physical
- * address directly, so if the DMA layer suggests it can't by
- * giving us back some translation, that bodes very badly...
+ * address directly, so if the DMA layer suggests otherwise by
+ * translating or truncating them, that bodes very badly...
*/
- if (dma != __arm_lpae_dma_addr(dev, pages))
+ if (dma != virt_to_phys(pages))
goto out_unmap;
}
@@ -243,10 +243,8 @@ out_free:
static void __arm_lpae_free_pages(void *pages, size_t size,
struct io_pgtable_cfg *cfg)
{
- struct device *dev = cfg->iommu_dev;
-
if (!selftest_running)
- dma_unmap_single(dev, __arm_lpae_dma_addr(dev, pages),
+ dma_unmap_single(cfg->iommu_dev, __arm_lpae_dma_addr(pages),
size, DMA_TO_DEVICE);
free_pages_exact(pages, size);
}
@@ -254,12 +252,11 @@ static void __arm_lpae_free_pages(void *pages, size_t size,
static void __arm_lpae_set_pte(arm_lpae_iopte *ptep, arm_lpae_iopte pte,
struct io_pgtable_cfg *cfg)
{
- struct device *dev = cfg->iommu_dev;
-
*ptep = pte;
if (!selftest_running)
- dma_sync_single_for_device(dev, __arm_lpae_dma_addr(dev, ptep),
+ dma_sync_single_for_device(cfg->iommu_dev,
+ __arm_lpae_dma_addr(ptep),
sizeof(pte), DMA_TO_DEVICE);
}
@@ -629,6 +626,11 @@ arm_lpae_alloc_pgtable(struct io_pgtable_cfg *cfg)
if (cfg->oas > ARM_LPAE_MAX_ADDR_BITS)
return NULL;
+ if (!selftest_running && cfg->iommu_dev->dma_pfn_offset) {
+ dev_err(cfg->iommu_dev, "Cannot accommodate DMA offset for IOMMU page tables\n");
+ return NULL;
+ }
+
data = kmalloc(sizeof(*data), GFP_KERNEL);
if (!data)
return NULL;