From aeae109c4a8e194415c765e3edbcfc742004cf39 Mon Sep 17 00:00:00 2001 From: Robin Murphy Date: Thu, 17 Sep 2015 17:42:16 +0100 Subject: 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. Change-Id: I2f7087d43e2d8f16ea36f8e10530d0c4811a4fcd Signed-off-by: Robin Murphy [will: folded in selftest fix from Yong Wu] Signed-off-by: Will Deacon --- drivers/iommu/Kconfig | 3 +-- drivers/iommu/io-pgtable-arm.c | 26 ++++++++++++++------------ 2 files changed, 15 insertions(+), 14 deletions(-) diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig index a87d4ceab106..d9a9eaf95db1 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 9cc1cf458954..379f76c4ec77 100644 --- a/drivers/iommu/io-pgtable-arm.c +++ b/drivers/iommu/io-pgtable-arm.c @@ -280,9 +280,9 @@ static void iopte_tblcnt_add(arm_lpae_iopte *table_ptep, int cnt) static bool suppress_map_failures; -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, @@ -303,10 +303,10 @@ 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; } @@ -323,23 +323,20 @@ out_free: static void __arm_lpae_free_pages(void *pages, size_t size, struct io_pgtable_cfg *cfg, void *cookie) { - struct device *dev = cfg->iommu_dev; - if (!selftest_running) - dma_unmap_single(dev, __arm_lpae_dma_addr(dev, pages), - size, DMA_TO_DEVICE); + dma_unmap_single(cfg->iommu_dev, __arm_lpae_dma_addr(pages), + size, DMA_TO_DEVICE); io_pgtable_free_pages_exact(cfg, cookie, pages, 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); } @@ -894,6 +891,11 @@ 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; -- cgit v1.2.3