From 33dcb37cef741294b481f4d889a465b8091f11bf Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Fri, 26 Jul 2019 09:26:40 +0200 Subject: [PATCH] dma-mapping: fix page attributes for dma_mmap_* All the way back to introducing dma_common_mmap we've defaulted to mark the pages as uncached. But this is wrong for DMA coherent devices. Later on DMA_ATTR_WRITE_COMBINE also got incorrect treatment as that flag is only treated special on the alloc side for non-coherent devices. Introduce a new dma_pgprot helper that deals with the check for coherent devices so that only the remapping cases ever reach arch_dma_mmap_pgprot and we thus ensure no aliasing of page attributes happens, which makes the powerpc version of arch_dma_mmap_pgprot obsolete and simplifies the remaining ones. Note that this means arch_dma_mmap_pgprot is a bit misnamed now, but we'll phase it out soon. Fixes: 64ccc9c033c6 ("common: dma-mapping: add support for generic dma_mmap_* calls") Reported-by: Shawn Anastasio Reported-by: Gavin Li Signed-off-by: Christoph Hellwig Acked-by: Catalin Marinas # arm64 --- arch/arm/mm/dma-mapping.c | 4 +--- arch/arm64/mm/dma-mapping.c | 4 +--- arch/powerpc/Kconfig | 1 - arch/powerpc/kernel/Makefile | 3 +-- arch/powerpc/kernel/dma-common.c | 17 ----------------- drivers/iommu/dma-iommu.c | 6 +++--- include/linux/dma-noncoherent.h | 13 +++++++++---- kernel/dma/mapping.c | 19 ++++++++++++++++++- kernel/dma/remap.c | 2 +- 9 files changed, 34 insertions(+), 35 deletions(-) delete mode 100644 arch/powerpc/kernel/dma-common.c diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c index 6774b03..d42557e 100644 --- a/arch/arm/mm/dma-mapping.c +++ b/arch/arm/mm/dma-mapping.c @@ -2405,9 +2405,7 @@ long arch_dma_coherent_to_pfn(struct device *dev, void *cpu_addr, pgprot_t arch_dma_mmap_pgprot(struct device *dev, pgprot_t prot, unsigned long attrs) { - if (!dev_is_dma_coherent(dev)) - return __get_dma_pgprot(attrs, prot); - return prot; + return __get_dma_pgprot(attrs, prot); } void *arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle, diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c index 1d3f0b5..bd2b039 100644 --- a/arch/arm64/mm/dma-mapping.c +++ b/arch/arm64/mm/dma-mapping.c @@ -14,9 +14,7 @@ pgprot_t arch_dma_mmap_pgprot(struct device *dev, pgprot_t prot, unsigned long attrs) { - if (!dev_is_dma_coherent(dev) || (attrs & DMA_ATTR_WRITE_COMBINE)) - return pgprot_writecombine(prot); - return prot; + return pgprot_writecombine(prot); } void arch_sync_dma_for_device(struct device *dev, phys_addr_t paddr, diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index 77f6ebf..d8dcd88 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -121,7 +121,6 @@ config PPC select ARCH_32BIT_OFF_T if PPC32 select ARCH_HAS_DEBUG_VIRTUAL select ARCH_HAS_DEVMEM_IS_ALLOWED - select ARCH_HAS_DMA_MMAP_PGPROT select ARCH_HAS_ELF_RANDOMIZE select ARCH_HAS_FORTIFY_SOURCE select ARCH_HAS_GCOV_PROFILE_ALL diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile index ea0c692..56dfa7a 100644 --- a/arch/powerpc/kernel/Makefile +++ b/arch/powerpc/kernel/Makefile @@ -49,8 +49,7 @@ obj-y := cputable.o ptrace.o syscalls.o \ signal.o sysfs.o cacheinfo.o time.o \ prom.o traps.o setup-common.o \ udbg.o misc.o io.o misc_$(BITS).o \ - of_platform.o prom_parse.o \ - dma-common.o + of_platform.o prom_parse.o obj-$(CONFIG_PPC64) += setup_64.o sys_ppc32.o \ signal_64.o ptrace32.o \ paca.o nvram_64.o firmware.o diff --git a/arch/powerpc/kernel/dma-common.c b/arch/powerpc/kernel/dma-common.c deleted file mode 100644 index dc7ef6b..0000000 --- a/arch/powerpc/kernel/dma-common.c +++ /dev/null @@ -1,17 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0-or-later -/* - * Contains common dma routines for all powerpc platforms. - * - * Copyright (C) 2019 Shawn Anastasio. - */ - -#include -#include - -pgprot_t arch_dma_mmap_pgprot(struct device *dev, pgprot_t prot, - unsigned long attrs) -{ - if (!dev_is_dma_coherent(dev)) - return pgprot_noncached(prot); - return prot; -} diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c index a7f9c3e..0015fe6 100644 --- a/drivers/iommu/dma-iommu.c +++ b/drivers/iommu/dma-iommu.c @@ -574,7 +574,7 @@ static void *iommu_dma_alloc_remap(struct device *dev, size_t size, struct iova_domain *iovad = &cookie->iovad; bool coherent = dev_is_dma_coherent(dev); int ioprot = dma_info_to_prot(DMA_BIDIRECTIONAL, coherent, attrs); - pgprot_t prot = arch_dma_mmap_pgprot(dev, PAGE_KERNEL, attrs); + pgprot_t prot = dma_pgprot(dev, PAGE_KERNEL, attrs); unsigned int count, min_size, alloc_sizes = domain->pgsize_bitmap; struct page **pages; struct sg_table sgt; @@ -975,7 +975,7 @@ static void *iommu_dma_alloc_pages(struct device *dev, size_t size, return NULL; if (IS_ENABLED(CONFIG_DMA_REMAP) && (!coherent || PageHighMem(page))) { - pgprot_t prot = arch_dma_mmap_pgprot(dev, PAGE_KERNEL, attrs); + pgprot_t prot = dma_pgprot(dev, PAGE_KERNEL, attrs); cpu_addr = dma_common_contiguous_remap(page, alloc_size, VM_USERMAP, prot, __builtin_return_address(0)); @@ -1035,7 +1035,7 @@ static int iommu_dma_mmap(struct device *dev, struct vm_area_struct *vma, unsigned long pfn, off = vma->vm_pgoff; int ret; - vma->vm_page_prot = arch_dma_mmap_pgprot(dev, vma->vm_page_prot, attrs); + vma->vm_page_prot = dma_pgprot(dev, vma->vm_page_prot, attrs); if (dma_mmap_from_dev_coherent(dev, vma, cpu_addr, size, &ret)) return ret; diff --git a/include/linux/dma-noncoherent.h b/include/linux/dma-noncoherent.h index 3813211..0bff3d7 100644 --- a/include/linux/dma-noncoherent.h +++ b/include/linux/dma-noncoherent.h @@ -42,13 +42,18 @@ void arch_dma_free(struct device *dev, size_t size, void *cpu_addr, dma_addr_t dma_addr, unsigned long attrs); long arch_dma_coherent_to_pfn(struct device *dev, void *cpu_addr, dma_addr_t dma_addr); - -#ifdef CONFIG_ARCH_HAS_DMA_MMAP_PGPROT pgprot_t arch_dma_mmap_pgprot(struct device *dev, pgprot_t prot, unsigned long attrs); + +#ifdef CONFIG_MMU +pgprot_t dma_pgprot(struct device *dev, pgprot_t prot, unsigned long attrs); #else -# define arch_dma_mmap_pgprot(dev, prot, attrs) pgprot_noncached(prot) -#endif +static inline pgprot_t dma_pgprot(struct device *dev, pgprot_t prot, + unsigned long attrs) +{ + return prot; /* no protection bits supported without page tables */ +} +#endif /* CONFIG_MMU */ #ifdef CONFIG_DMA_NONCOHERENT_CACHE_SYNC void arch_dma_cache_sync(struct device *dev, void *vaddr, size_t size, diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c index b945239..b0038ca 100644 --- a/kernel/dma/mapping.c +++ b/kernel/dma/mapping.c @@ -150,6 +150,23 @@ int dma_get_sgtable_attrs(struct device *dev, struct sg_table *sgt, } EXPORT_SYMBOL(dma_get_sgtable_attrs); +#ifdef CONFIG_MMU +/* + * Return the page attributes used for mapping dma_alloc_* memory, either in + * kernel space if remapping is needed, or to userspace through dma_mmap_*. + */ +pgprot_t dma_pgprot(struct device *dev, pgprot_t prot, unsigned long attrs) +{ + if (dev_is_dma_coherent(dev) || + (IS_ENABLED(CONFIG_DMA_NONCOHERENT_CACHE_SYNC) && + (attrs & DMA_ATTR_NON_CONSISTENT))) + return prot; + if (IS_ENABLED(CONFIG_ARCH_HAS_DMA_MMAP_PGPROT)) + return arch_dma_mmap_pgprot(dev, prot, attrs); + return pgprot_noncached(prot); +} +#endif /* CONFIG_MMU */ + /* * Create userspace mapping for the DMA-coherent memory. */ @@ -164,7 +181,7 @@ int dma_common_mmap(struct device *dev, struct vm_area_struct *vma, unsigned long pfn; int ret = -ENXIO; - vma->vm_page_prot = arch_dma_mmap_pgprot(dev, vma->vm_page_prot, attrs); + vma->vm_page_prot = dma_pgprot(dev, vma->vm_page_prot, attrs); if (dma_mmap_from_dev_coherent(dev, vma, cpu_addr, size, &ret)) return ret; diff --git a/kernel/dma/remap.c b/kernel/dma/remap.c index a594aec..ffe78f0 100644 --- a/kernel/dma/remap.c +++ b/kernel/dma/remap.c @@ -218,7 +218,7 @@ void *arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle, /* create a coherent mapping */ ret = dma_common_contiguous_remap(page, size, VM_USERMAP, - arch_dma_mmap_pgprot(dev, PAGE_KERNEL, attrs), + dma_pgprot(dev, PAGE_KERNEL, attrs), __builtin_return_address(0)); if (!ret) { __dma_direct_free_pages(dev, size, page); -- 2.7.4