[07/26] iommu/dma: move the arm64 wrappers to common code
diff mbox series

Message ID 20190422175942.18788-8-hch@lst.de
State New, archived
Headers show
Series
  • [01/26] arm64/iommu: handle non-remapped addresses in ->mmap and ->get_sgtable
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Commit Message

hch@lst.de April 22, 2019, 5:59 p.m. UTC
There is nothing really arm64 specific in the iommu_dma_ops
implementation, so move it to dma-iommu.c and keep a lot of symbols
self-contained.  Note the implementation does depend on the
DMA_DIRECT_REMAP infrastructure for now, so we'll have to make the
DMA_IOMMU support depend on it, but this will be relaxed soon.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 arch/arm64/mm/dma-mapping.c | 389 +-----------------------------------
 drivers/iommu/Kconfig       |   1 +
 drivers/iommu/dma-iommu.c   | 388 ++++++++++++++++++++++++++++++++---
 include/linux/dma-iommu.h   |  43 +---
 4 files changed, 369 insertions(+), 452 deletions(-)

Comments

Robin Murphy April 29, 2019, 12:56 p.m. UTC | #1
On 22/04/2019 18:59, Christoph Hellwig wrote:
> There is nothing really arm64 specific in the iommu_dma_ops
> implementation, so move it to dma-iommu.c and keep a lot of symbols
> self-contained.  Note the implementation does depend on the
> DMA_DIRECT_REMAP infrastructure for now, so we'll have to make the
> DMA_IOMMU support depend on it, but this will be relaxed soon.

Nothing looks objectionable, and boot testing with this much of the 
series merged has my coherent and non-coherent IOMMU-backed devices 
appearing to still work OK, so:

Acked-by: Robin Murphy <robin.murphy@arm.com>

> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>   arch/arm64/mm/dma-mapping.c | 389 +-----------------------------------
>   drivers/iommu/Kconfig       |   1 +
>   drivers/iommu/dma-iommu.c   | 388 ++++++++++++++++++++++++++++++++---
>   include/linux/dma-iommu.h   |  43 +---
>   4 files changed, 369 insertions(+), 452 deletions(-)
> 
> diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c
> index 636fa7c64370..d1661f78eb4d 100644
> --- a/arch/arm64/mm/dma-mapping.c
> +++ b/arch/arm64/mm/dma-mapping.c
> @@ -27,6 +27,7 @@
>   #include <linux/dma-direct.h>
>   #include <linux/dma-noncoherent.h>
>   #include <linux/dma-contiguous.h>
> +#include <linux/dma-iommu.h>
>   #include <linux/vmalloc.h>
>   #include <linux/swiotlb.h>
>   #include <linux/pci.h>
> @@ -58,27 +59,6 @@ void arch_dma_prep_coherent(struct page *page, size_t size)
>   	__dma_flush_area(page_address(page), size);
>   }
>   
> -#ifdef CONFIG_IOMMU_DMA
> -static int __swiotlb_get_sgtable_page(struct sg_table *sgt,
> -				      struct page *page, size_t size)
> -{
> -	int ret = sg_alloc_table(sgt, 1, GFP_KERNEL);
> -
> -	if (!ret)
> -		sg_set_page(sgt->sgl, page, PAGE_ALIGN(size), 0);
> -
> -	return ret;
> -}
> -
> -static int __swiotlb_mmap_pfn(struct vm_area_struct *vma,
> -			      unsigned long pfn, size_t size)
> -{
> -	return remap_pfn_range(vma, vma->vm_start, pfn + vma->vm_pgoff,
> -			      vma->vm_end - vma->vm_start,
> -			      vma->vm_page_prot);
> -}
> -#endif /* CONFIG_IOMMU_DMA */
> -
>   static int __init arm64_dma_init(void)
>   {
>   	WARN_TAINT(ARCH_DMA_MINALIGN < cache_line_size(),
> @@ -90,379 +70,18 @@ static int __init arm64_dma_init(void)
>   arch_initcall(arm64_dma_init);
>   
>   #ifdef CONFIG_IOMMU_DMA
> -#include <linux/dma-iommu.h>
> -#include <linux/platform_device.h>
> -#include <linux/amba/bus.h>
> -
> -static void *__iommu_alloc_attrs(struct device *dev, size_t size,
> -				 dma_addr_t *handle, gfp_t gfp,
> -				 unsigned long attrs)
> -{
> -	bool coherent = dev_is_dma_coherent(dev);
> -	int ioprot = dma_info_to_prot(DMA_BIDIRECTIONAL, coherent, attrs);
> -	size_t iosize = size;
> -	void *addr;
> -
> -	if (WARN(!dev, "cannot create IOMMU mapping for unknown device\n"))
> -		return NULL;
> -
> -	size = PAGE_ALIGN(size);
> -
> -	/*
> -	 * Some drivers rely on this, and we probably don't want the
> -	 * possibility of stale kernel data being read by devices anyway.
> -	 */
> -	gfp |= __GFP_ZERO;
> -
> -	if (!gfpflags_allow_blocking(gfp)) {
> -		struct page *page;
> -		/*
> -		 * In atomic context we can't remap anything, so we'll only
> -		 * get the virtually contiguous buffer we need by way of a
> -		 * physically contiguous allocation.
> -		 */
> -		if (coherent) {
> -			page = alloc_pages(gfp, get_order(size));
> -			addr = page ? page_address(page) : NULL;
> -		} else {
> -			addr = dma_alloc_from_pool(size, &page, gfp);
> -		}
> -		if (!addr)
> -			return NULL;
> -
> -		*handle = iommu_dma_map_page(dev, page, 0, iosize, ioprot);
> -		if (*handle == DMA_MAPPING_ERROR) {
> -			if (coherent)
> -				__free_pages(page, get_order(size));
> -			else
> -				dma_free_from_pool(addr, size);
> -			addr = NULL;
> -		}
> -	} else if (attrs & DMA_ATTR_FORCE_CONTIGUOUS) {
> -		pgprot_t prot = arch_dma_mmap_pgprot(dev, PAGE_KERNEL, attrs);
> -		struct page *page;
> -
> -		page = dma_alloc_from_contiguous(dev, size >> PAGE_SHIFT,
> -					get_order(size), gfp & __GFP_NOWARN);
> -		if (!page)
> -			return NULL;
> -
> -		*handle = iommu_dma_map_page(dev, page, 0, iosize, ioprot);
> -		if (*handle == DMA_MAPPING_ERROR) {
> -			dma_release_from_contiguous(dev, page,
> -						    size >> PAGE_SHIFT);
> -			return NULL;
> -		}
> -		addr = dma_common_contiguous_remap(page, size, VM_USERMAP,
> -						   prot,
> -						   __builtin_return_address(0));
> -		if (addr) {
> -			if (!coherent)
> -				__dma_flush_area(page_to_virt(page), iosize);
> -			memset(addr, 0, size);
> -		} else {
> -			iommu_dma_unmap_page(dev, *handle, iosize, 0, attrs);
> -			dma_release_from_contiguous(dev, page,
> -						    size >> PAGE_SHIFT);
> -		}
> -	} else {
> -		pgprot_t prot = arch_dma_mmap_pgprot(dev, PAGE_KERNEL, attrs);
> -		struct page **pages;
> -
> -		pages = iommu_dma_alloc(dev, iosize, gfp, attrs, ioprot,
> -					handle);
> -		if (!pages)
> -			return NULL;
> -
> -		addr = dma_common_pages_remap(pages, size, VM_USERMAP, prot,
> -					      __builtin_return_address(0));
> -		if (!addr)
> -			iommu_dma_free(dev, pages, iosize, handle);
> -	}
> -	return addr;
> -}
> -
> -static void __iommu_free_attrs(struct device *dev, size_t size, void *cpu_addr,
> -			       dma_addr_t handle, unsigned long attrs)
> -{
> -	size_t iosize = size;
> -
> -	size = PAGE_ALIGN(size);
> -	/*
> -	 * @cpu_addr will be one of 4 things depending on how it was allocated:
> -	 * - A remapped array of pages for contiguous allocations.
> -	 * - A remapped array of pages from iommu_dma_alloc(), for all
> -	 *   non-atomic allocations.
> -	 * - A non-cacheable alias from the atomic pool, for atomic
> -	 *   allocations by non-coherent devices.
> -	 * - A normal lowmem address, for atomic allocations by
> -	 *   coherent devices.
> -	 * Hence how dodgy the below logic looks...
> -	 */
> -	if (dma_in_atomic_pool(cpu_addr, size)) {
> -		iommu_dma_unmap_page(dev, handle, iosize, 0, 0);
> -		dma_free_from_pool(cpu_addr, size);
> -	} else if (attrs & DMA_ATTR_FORCE_CONTIGUOUS) {
> -		struct page *page = vmalloc_to_page(cpu_addr);
> -
> -		iommu_dma_unmap_page(dev, handle, iosize, 0, attrs);
> -		dma_release_from_contiguous(dev, page, size >> PAGE_SHIFT);
> -		dma_common_free_remap(cpu_addr, size, VM_USERMAP);
> -	} else if (is_vmalloc_addr(cpu_addr)){
> -		struct vm_struct *area = find_vm_area(cpu_addr);
> -
> -		if (WARN_ON(!area || !area->pages))
> -			return;
> -		iommu_dma_free(dev, area->pages, iosize, &handle);
> -		dma_common_free_remap(cpu_addr, size, VM_USERMAP);
> -	} else {
> -		iommu_dma_unmap_page(dev, handle, iosize, 0, 0);
> -		__free_pages(virt_to_page(cpu_addr), get_order(size));
> -	}
> -}
> -
> -static int __iommu_mmap_attrs(struct device *dev, struct vm_area_struct *vma,
> -			      void *cpu_addr, dma_addr_t dma_addr, size_t size,
> -			      unsigned long attrs)
> -{
> -	unsigned long nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
> -	unsigned long off = vma->vm_pgoff;
> -	struct vm_struct *area;
> -	int ret;
> -
> -	vma->vm_page_prot = arch_dma_mmap_pgprot(dev, vma->vm_page_prot, attrs);
> -
> -	if (dma_mmap_from_dev_coherent(dev, vma, cpu_addr, size, &ret))
> -		return ret;
> -
> -	if (off >= nr_pages || vma_pages(vma) > nr_pages - off)
> -		return -ENXIO;
> -
> -	if (!is_vmalloc_addr(cpu_addr)) {
> -		unsigned long pfn = page_to_pfn(virt_to_page(cpu_addr));
> -		return __swiotlb_mmap_pfn(vma, pfn, size);
> -	}
> -
> -	if (attrs & DMA_ATTR_FORCE_CONTIGUOUS) {
> -		/*
> -		 * DMA_ATTR_FORCE_CONTIGUOUS allocations are always remapped,
> -		 * hence in the vmalloc space.
> -		 */
> -		unsigned long pfn = vmalloc_to_pfn(cpu_addr);
> -		return __swiotlb_mmap_pfn(vma, pfn, size);
> -	}
> -
> -	area = find_vm_area(cpu_addr);
> -	if (WARN_ON(!area || !area->pages))
> -		return -ENXIO;
> -
> -	return iommu_dma_mmap(area->pages, size, vma);
> -}
> -
> -static int __iommu_get_sgtable(struct device *dev, struct sg_table *sgt,
> -			       void *cpu_addr, dma_addr_t dma_addr,
> -			       size_t size, unsigned long attrs)
> -{
> -	unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
> -	struct vm_struct *area = find_vm_area(cpu_addr);
> -
> -	if (!is_vmalloc_addr(cpu_addr)) {
> -		struct page *page = virt_to_page(cpu_addr);
> -		return __swiotlb_get_sgtable_page(sgt, page, size);
> -	}
> -
> -	if (attrs & DMA_ATTR_FORCE_CONTIGUOUS) {
> -		/*
> -		 * DMA_ATTR_FORCE_CONTIGUOUS allocations are always remapped,
> -		 * hence in the vmalloc space.
> -		 */
> -		struct page *page = vmalloc_to_page(cpu_addr);
> -		return __swiotlb_get_sgtable_page(sgt, page, size);
> -	}
> -
> -	if (WARN_ON(!area || !area->pages))
> -		return -ENXIO;
> -
> -	return sg_alloc_table_from_pages(sgt, area->pages, count, 0, size,
> -					 GFP_KERNEL);
> -}
> -
> -static void __iommu_sync_single_for_cpu(struct device *dev,
> -					dma_addr_t dev_addr, size_t size,
> -					enum dma_data_direction dir)
> -{
> -	phys_addr_t phys;
> -
> -	if (dev_is_dma_coherent(dev))
> -		return;
> -
> -	phys = iommu_iova_to_phys(iommu_get_dma_domain(dev), dev_addr);
> -	arch_sync_dma_for_cpu(dev, phys, size, dir);
> -}
> -
> -static void __iommu_sync_single_for_device(struct device *dev,
> -					   dma_addr_t dev_addr, size_t size,
> -					   enum dma_data_direction dir)
> -{
> -	phys_addr_t phys;
> -
> -	if (dev_is_dma_coherent(dev))
> -		return;
> -
> -	phys = iommu_iova_to_phys(iommu_get_dma_domain(dev), dev_addr);
> -	arch_sync_dma_for_device(dev, phys, size, dir);
> -}
> -
> -static dma_addr_t __iommu_map_page(struct device *dev, struct page *page,
> -				   unsigned long offset, size_t size,
> -				   enum dma_data_direction dir,
> -				   unsigned long attrs)
> -{
> -	bool coherent = dev_is_dma_coherent(dev);
> -	int prot = dma_info_to_prot(dir, coherent, attrs);
> -	dma_addr_t dev_addr = iommu_dma_map_page(dev, page, offset, size, prot);
> -
> -	if (!coherent && !(attrs & DMA_ATTR_SKIP_CPU_SYNC) &&
> -	    dev_addr != DMA_MAPPING_ERROR)
> -		__dma_map_area(page_address(page) + offset, size, dir);
> -
> -	return dev_addr;
> -}
> -
> -static void __iommu_unmap_page(struct device *dev, dma_addr_t dev_addr,
> -			       size_t size, enum dma_data_direction dir,
> -			       unsigned long attrs)
> -{
> -	if ((attrs & DMA_ATTR_SKIP_CPU_SYNC) == 0)
> -		__iommu_sync_single_for_cpu(dev, dev_addr, size, dir);
> -
> -	iommu_dma_unmap_page(dev, dev_addr, size, dir, attrs);
> -}
> -
> -static void __iommu_sync_sg_for_cpu(struct device *dev,
> -				    struct scatterlist *sgl, int nelems,
> -				    enum dma_data_direction dir)
> -{
> -	struct scatterlist *sg;
> -	int i;
> -
> -	if (dev_is_dma_coherent(dev))
> -		return;
> -
> -	for_each_sg(sgl, sg, nelems, i)
> -		arch_sync_dma_for_cpu(dev, sg_phys(sg), sg->length, dir);
> -}
> -
> -static void __iommu_sync_sg_for_device(struct device *dev,
> -				       struct scatterlist *sgl, int nelems,
> -				       enum dma_data_direction dir)
> -{
> -	struct scatterlist *sg;
> -	int i;
> -
> -	if (dev_is_dma_coherent(dev))
> -		return;
> -
> -	for_each_sg(sgl, sg, nelems, i)
> -		arch_sync_dma_for_device(dev, sg_phys(sg), sg->length, dir);
> -}
> -
> -static int __iommu_map_sg_attrs(struct device *dev, struct scatterlist *sgl,
> -				int nelems, enum dma_data_direction dir,
> -				unsigned long attrs)
> -{
> -	bool coherent = dev_is_dma_coherent(dev);
> -
> -	if ((attrs & DMA_ATTR_SKIP_CPU_SYNC) == 0)
> -		__iommu_sync_sg_for_device(dev, sgl, nelems, dir);
> -
> -	return iommu_dma_map_sg(dev, sgl, nelems,
> -				dma_info_to_prot(dir, coherent, attrs));
> -}
> -
> -static void __iommu_unmap_sg_attrs(struct device *dev,
> -				   struct scatterlist *sgl, int nelems,
> -				   enum dma_data_direction dir,
> -				   unsigned long attrs)
> -{
> -	if ((attrs & DMA_ATTR_SKIP_CPU_SYNC) == 0)
> -		__iommu_sync_sg_for_cpu(dev, sgl, nelems, dir);
> -
> -	iommu_dma_unmap_sg(dev, sgl, nelems, dir, attrs);
> -}
> -
> -static const struct dma_map_ops iommu_dma_ops = {
> -	.alloc = __iommu_alloc_attrs,
> -	.free = __iommu_free_attrs,
> -	.mmap = __iommu_mmap_attrs,
> -	.get_sgtable = __iommu_get_sgtable,
> -	.map_page = __iommu_map_page,
> -	.unmap_page = __iommu_unmap_page,
> -	.map_sg = __iommu_map_sg_attrs,
> -	.unmap_sg = __iommu_unmap_sg_attrs,
> -	.sync_single_for_cpu = __iommu_sync_single_for_cpu,
> -	.sync_single_for_device = __iommu_sync_single_for_device,
> -	.sync_sg_for_cpu = __iommu_sync_sg_for_cpu,
> -	.sync_sg_for_device = __iommu_sync_sg_for_device,
> -	.map_resource = iommu_dma_map_resource,
> -	.unmap_resource = iommu_dma_unmap_resource,
> -};
> -
> -static int __init __iommu_dma_init(void)
> -{
> -	return iommu_dma_init();
> -}
> -arch_initcall(__iommu_dma_init);
> -
> -static void __iommu_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
> -				  const struct iommu_ops *ops)
> -{
> -	struct iommu_domain *domain;
> -
> -	if (!ops)
> -		return;
> -
> -	/*
> -	 * The IOMMU core code allocates the default DMA domain, which the
> -	 * underlying IOMMU driver needs to support via the dma-iommu layer.
> -	 */
> -	domain = iommu_get_domain_for_dev(dev);
> -
> -	if (!domain)
> -		goto out_err;
> -
> -	if (domain->type == IOMMU_DOMAIN_DMA) {
> -		if (iommu_dma_init_domain(domain, dma_base, size, dev))
> -			goto out_err;
> -
> -		dev->dma_ops = &iommu_dma_ops;
> -	}
> -
> -	return;
> -
> -out_err:
> -	 pr_warn("Failed to set up IOMMU for device %s; retaining platform DMA ops\n",
> -		 dev_name(dev));
> -}
> -
>   void arch_teardown_dma_ops(struct device *dev)
>   {
>   	dev->dma_ops = NULL;
>   }
> -
> -#else
> -
> -static void __iommu_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
> -				  const struct iommu_ops *iommu)
> -{ }
> -
> -#endif  /* CONFIG_IOMMU_DMA */
> +#endif
>   
>   void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
>   			const struct iommu_ops *iommu, bool coherent)
>   {
>   	dev->dma_coherent = coherent;
> -	__iommu_setup_dma_ops(dev, dma_base, size, iommu);
> +	if (iommu)
> +		iommu_setup_dma_ops(dev, dma_base, size);
>   
>   #ifdef CONFIG_XEN
>   	if (xen_initial_domain())
> diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
> index 6f07f3b21816..bdc14baf2ee5 100644
> --- a/drivers/iommu/Kconfig
> +++ b/drivers/iommu/Kconfig
> @@ -95,6 +95,7 @@ config IOMMU_DMA
>   	select IOMMU_API
>   	select IOMMU_IOVA
>   	select NEED_SG_DMA_LENGTH
> +	depends on DMA_DIRECT_REMAP
>   
>   config FSL_PAMU
>   	bool "Freescale IOMMU support"
> diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
> index f915cb7c46e6..622123551bba 100644
> --- a/drivers/iommu/dma-iommu.c
> +++ b/drivers/iommu/dma-iommu.c
> @@ -21,6 +21,7 @@
>   
>   #include <linux/acpi_iort.h>
>   #include <linux/device.h>
> +#include <linux/dma-contiguous.h>
>   #include <linux/dma-iommu.h>
>   #include <linux/dma-noncoherent.h>
>   #include <linux/gfp.h>
> @@ -79,11 +80,6 @@ static struct iommu_dma_cookie *cookie_alloc(enum iommu_dma_cookie_type type)
>   	return cookie;
>   }
>   
> -int iommu_dma_init(void)
> -{
> -	return iova_cache_get();
> -}
> -
>   /**
>    * iommu_get_dma_cookie - Acquire DMA-API resources for a domain
>    * @domain: IOMMU domain to prepare for DMA-API usage
> @@ -285,7 +281,7 @@ static void iommu_dma_flush_iotlb_all(struct iova_domain *iovad)
>    * to ensure it is an invalid IOVA. It is safe to reinitialise a domain, but
>    * any change which could make prior IOVAs invalid will fail.
>    */
> -int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base,
> +static int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base,
>   		u64 size, struct device *dev)
>   {
>   	struct iommu_dma_cookie *cookie = domain->iova_cookie;
> @@ -336,7 +332,6 @@ int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base,
>   
>   	return iova_reserve_iommu_regions(dev, domain);
>   }
> -EXPORT_SYMBOL(iommu_dma_init_domain);
>   
>   /**
>    * dma_info_to_prot - Translate DMA API directions and attributes to IOMMU API
> @@ -347,7 +342,7 @@ EXPORT_SYMBOL(iommu_dma_init_domain);
>    *
>    * Return: corresponding IOMMU API page protection flags
>    */
> -int dma_info_to_prot(enum dma_data_direction dir, bool coherent,
> +static int dma_info_to_prot(enum dma_data_direction dir, bool coherent,
>   		     unsigned long attrs)
>   {
>   	int prot = coherent ? IOMMU_CACHE : 0;
> @@ -506,17 +501,17 @@ static struct page **__iommu_dma_alloc_pages(struct device *dev,
>   }
>   
>   /**
> - * iommu_dma_free - Free a buffer allocated by iommu_dma_alloc()
> + * iommu_dma_free - Free a buffer allocated by __iommu_dma_alloc()
>    * @dev: Device which owns this buffer
> - * @pages: Array of buffer pages as returned by iommu_dma_alloc()
> + * @pages: Array of buffer pages as returned by __iommu_dma_alloc()
>    * @size: Size of buffer in bytes
>    * @handle: DMA address of buffer
>    *
>    * Frees both the pages associated with the buffer, and the array
>    * describing them
>    */
> -void iommu_dma_free(struct device *dev, struct page **pages, size_t size,
> -		dma_addr_t *handle)
> +static void __iommu_dma_free(struct device *dev, struct page **pages,
> +		size_t size, dma_addr_t *handle)
>   {
>   	__iommu_dma_unmap(iommu_get_dma_domain(dev), *handle, size);
>   	__iommu_dma_free_pages(pages, PAGE_ALIGN(size) >> PAGE_SHIFT);
> @@ -524,7 +519,7 @@ void iommu_dma_free(struct device *dev, struct page **pages, size_t size,
>   }
>   
>   /**
> - * iommu_dma_alloc - Allocate and map a buffer contiguous in IOVA space
> + * __iommu_dma_alloc - Allocate and map a buffer contiguous in IOVA space
>    * @dev: Device to allocate memory for. Must be a real device
>    *	 attached to an iommu_dma_domain
>    * @size: Size of buffer in bytes
> @@ -539,8 +534,8 @@ void iommu_dma_free(struct device *dev, struct page **pages, size_t size,
>    * Return: Array of struct page pointers describing the buffer,
>    *	   or NULL on failure.
>    */
> -struct page **iommu_dma_alloc(struct device *dev, size_t size, gfp_t gfp,
> -		unsigned long attrs, int prot, dma_addr_t *handle)
> +static struct page **__iommu_dma_alloc(struct device *dev, size_t size,
> +		gfp_t gfp, unsigned long attrs, int prot, dma_addr_t *handle)
>   {
>   	struct iommu_domain *domain = iommu_get_dma_domain(dev);
>   	struct iommu_dma_cookie *cookie = domain->iova_cookie;
> @@ -602,16 +597,16 @@ struct page **iommu_dma_alloc(struct device *dev, size_t size, gfp_t gfp,
>   }
>   
>   /**
> - * iommu_dma_mmap - Map a buffer into provided user VMA
> - * @pages: Array representing buffer from iommu_dma_alloc()
> + * __iommu_dma_mmap - Map a buffer into provided user VMA
> + * @pages: Array representing buffer from __iommu_dma_alloc()
>    * @size: Size of buffer in bytes
>    * @vma: VMA describing requested userspace mapping
>    *
>    * Maps the pages of the buffer in @pages into @vma. The caller is responsible
>    * for verifying the correct size and protection of @vma beforehand.
>    */
> -
> -int iommu_dma_mmap(struct page **pages, size_t size, struct vm_area_struct *vma)
> +static int __iommu_dma_mmap(struct page **pages, size_t size,
> +		struct vm_area_struct *vma)
>   {
>   	unsigned long uaddr = vma->vm_start;
>   	unsigned int i, count = PAGE_ALIGN(size) >> PAGE_SHIFT;
> @@ -626,6 +621,58 @@ int iommu_dma_mmap(struct page **pages, size_t size, struct vm_area_struct *vma)
>   	return ret;
>   }
>   
> +static void iommu_dma_sync_single_for_cpu(struct device *dev,
> +		dma_addr_t dma_handle, size_t size, enum dma_data_direction dir)
> +{
> +	phys_addr_t phys;
> +
> +	if (dev_is_dma_coherent(dev))
> +		return;
> +
> +	phys = iommu_iova_to_phys(iommu_get_dma_domain(dev), dma_handle);
> +	arch_sync_dma_for_cpu(dev, phys, size, dir);
> +}
> +
> +static void iommu_dma_sync_single_for_device(struct device *dev,
> +		dma_addr_t dma_handle, size_t size, enum dma_data_direction dir)
> +{
> +	phys_addr_t phys;
> +
> +	if (dev_is_dma_coherent(dev))
> +		return;
> +
> +	phys = iommu_iova_to_phys(iommu_get_dma_domain(dev), dma_handle);
> +	arch_sync_dma_for_device(dev, phys, size, dir);
> +}
> +
> +static void iommu_dma_sync_sg_for_cpu(struct device *dev,
> +		struct scatterlist *sgl, int nelems,
> +		enum dma_data_direction dir)
> +{
> +	struct scatterlist *sg;
> +	int i;
> +
> +	if (dev_is_dma_coherent(dev))
> +		return;
> +
> +	for_each_sg(sgl, sg, nelems, i)
> +		arch_sync_dma_for_cpu(dev, sg_phys(sg), sg->length, dir);
> +}
> +
> +static void iommu_dma_sync_sg_for_device(struct device *dev,
> +		struct scatterlist *sgl, int nelems,
> +		enum dma_data_direction dir)
> +{
> +	struct scatterlist *sg;
> +	int i;
> +
> +	if (dev_is_dma_coherent(dev))
> +		return;
> +
> +	for_each_sg(sgl, sg, nelems, i)
> +		arch_sync_dma_for_device(dev, sg_phys(sg), sg->length, dir);
> +}
> +
>   static dma_addr_t __iommu_dma_map(struct device *dev, phys_addr_t phys,
>   		size_t size, int prot, struct iommu_domain *domain)
>   {
> @@ -649,19 +696,44 @@ static dma_addr_t __iommu_dma_map(struct device *dev, phys_addr_t phys,
>   	return iova + iova_off;
>   }
>   
> -dma_addr_t iommu_dma_map_page(struct device *dev, struct page *page,
> +static dma_addr_t __iommu_dma_map_page(struct device *dev, struct page *page,
>   		unsigned long offset, size_t size, int prot)
>   {
>   	return __iommu_dma_map(dev, page_to_phys(page) + offset, size, prot,
>   			iommu_get_dma_domain(dev));
>   }
>   
> -void iommu_dma_unmap_page(struct device *dev, dma_addr_t handle, size_t size,
> -		enum dma_data_direction dir, unsigned long attrs)
> +static void __iommu_dma_unmap_page(struct device *dev, dma_addr_t handle,
> +		size_t size, enum dma_data_direction dir, unsigned long attrs)
>   {
>   	__iommu_dma_unmap(iommu_get_dma_domain(dev), handle, size);
>   }
>   
> +static dma_addr_t iommu_dma_map_page(struct device *dev, struct page *page,
> +		unsigned long offset, size_t size, enum dma_data_direction dir,
> +		unsigned long attrs)
> +{
> +	phys_addr_t phys = page_to_phys(page) + offset;
> +	bool coherent = dev_is_dma_coherent(dev);
> +	dma_addr_t dma_handle;
> +
> +	dma_handle =__iommu_dma_map(dev, phys, size,
> +			dma_info_to_prot(dir, coherent, attrs),
> +			iommu_get_dma_domain(dev));
> +	if (!coherent && !(attrs & DMA_ATTR_SKIP_CPU_SYNC) &&
> +	    dma_handle != DMA_MAPPING_ERROR)
> +		arch_sync_dma_for_device(dev, phys, size, dir);
> +	return dma_handle;
> +}
> +
> +static void iommu_dma_unmap_page(struct device *dev, dma_addr_t dma_handle,
> +		size_t size, enum dma_data_direction dir, unsigned long attrs)
> +{
> +	if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
> +		iommu_dma_sync_single_for_cpu(dev, dma_handle, size, dir);
> +	__iommu_dma_unmap(iommu_get_dma_domain(dev), dma_handle, size);
> +}
> +
>   /*
>    * Prepare a successfully-mapped scatterlist to give back to the caller.
>    *
> @@ -744,18 +816,22 @@ static void __invalidate_sg(struct scatterlist *sg, int nents)
>    * impedance-matching, to be able to hand off a suitably-aligned list,
>    * but still preserve the original offsets and sizes for the caller.
>    */
> -int iommu_dma_map_sg(struct device *dev, struct scatterlist *sg,
> -		int nents, int prot)
> +static int iommu_dma_map_sg(struct device *dev, struct scatterlist *sg,
> +		int nents, enum dma_data_direction dir, unsigned long attrs)
>   {
>   	struct iommu_domain *domain = iommu_get_dma_domain(dev);
>   	struct iommu_dma_cookie *cookie = domain->iova_cookie;
>   	struct iova_domain *iovad = &cookie->iovad;
>   	struct scatterlist *s, *prev = NULL;
> +	int prot = dma_info_to_prot(dir, dev_is_dma_coherent(dev), attrs);
>   	dma_addr_t iova;
>   	size_t iova_len = 0;
>   	unsigned long mask = dma_get_seg_boundary(dev);
>   	int i;
>   
> +	if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
> +		iommu_dma_sync_sg_for_device(dev, sg, nents, dir);
> +
>   	/*
>   	 * Work out how much IOVA space we need, and align the segments to
>   	 * IOVA granules for the IOMMU driver to handle. With some clever
> @@ -815,12 +891,16 @@ int iommu_dma_map_sg(struct device *dev, struct scatterlist *sg,
>   	return 0;
>   }
>   
> -void iommu_dma_unmap_sg(struct device *dev, struct scatterlist *sg, int nents,
> -		enum dma_data_direction dir, unsigned long attrs)
> +static void iommu_dma_unmap_sg(struct device *dev, struct scatterlist *sg,
> +		int nents, enum dma_data_direction dir, unsigned long attrs)
>   {
>   	dma_addr_t start, end;
>   	struct scatterlist *tmp;
>   	int i;
> +
> +	if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC) == 0)
> +		iommu_dma_sync_sg_for_cpu(dev, sg, nents, dir);
> +
>   	/*
>   	 * The scatterlist segments are mapped into a single
>   	 * contiguous IOVA allocation, so this is incredibly easy.
> @@ -835,7 +915,7 @@ void iommu_dma_unmap_sg(struct device *dev, struct scatterlist *sg, int nents,
>   	__iommu_dma_unmap(iommu_get_dma_domain(dev), start, end - start);
>   }
>   
> -dma_addr_t iommu_dma_map_resource(struct device *dev, phys_addr_t phys,
> +static dma_addr_t iommu_dma_map_resource(struct device *dev, phys_addr_t phys,
>   		size_t size, enum dma_data_direction dir, unsigned long attrs)
>   {
>   	return __iommu_dma_map(dev, phys, size,
> @@ -843,12 +923,258 @@ dma_addr_t iommu_dma_map_resource(struct device *dev, phys_addr_t phys,
>   			iommu_get_dma_domain(dev));
>   }
>   
> -void iommu_dma_unmap_resource(struct device *dev, dma_addr_t handle,
> +static void iommu_dma_unmap_resource(struct device *dev, dma_addr_t handle,
>   		size_t size, enum dma_data_direction dir, unsigned long attrs)
>   {
>   	__iommu_dma_unmap(iommu_get_dma_domain(dev), handle, size);
>   }
>   
> +static void *iommu_dma_alloc(struct device *dev, size_t size,
> +		dma_addr_t *handle, gfp_t gfp, unsigned long attrs)
> +{
> +	bool coherent = dev_is_dma_coherent(dev);
> +	int ioprot = dma_info_to_prot(DMA_BIDIRECTIONAL, coherent, attrs);
> +	size_t iosize = size;
> +	void *addr;
> +
> +	size = PAGE_ALIGN(size);
> +	gfp |= __GFP_ZERO;
> +
> +	if (!gfpflags_allow_blocking(gfp)) {
> +		struct page *page;
> +		/*
> +		 * In atomic context we can't remap anything, so we'll only
> +		 * get the virtually contiguous buffer we need by way of a
> +		 * physically contiguous allocation.
> +		 */
> +		if (coherent) {
> +			page = alloc_pages(gfp, get_order(size));
> +			addr = page ? page_address(page) : NULL;
> +		} else {
> +			addr = dma_alloc_from_pool(size, &page, gfp);
> +		}
> +		if (!addr)
> +			return NULL;
> +
> +		*handle = __iommu_dma_map_page(dev, page, 0, iosize, ioprot);
> +		if (*handle == DMA_MAPPING_ERROR) {
> +			if (coherent)
> +				__free_pages(page, get_order(size));
> +			else
> +				dma_free_from_pool(addr, size);
> +			addr = NULL;
> +		}
> +	} else if (attrs & DMA_ATTR_FORCE_CONTIGUOUS) {
> +		pgprot_t prot = arch_dma_mmap_pgprot(dev, PAGE_KERNEL, attrs);
> +		struct page *page;
> +
> +		page = dma_alloc_from_contiguous(dev, size >> PAGE_SHIFT,
> +					get_order(size), gfp & __GFP_NOWARN);
> +		if (!page)
> +			return NULL;
> +
> +		*handle = __iommu_dma_map_page(dev, page, 0, iosize, ioprot);
> +		if (*handle == DMA_MAPPING_ERROR) {
> +			dma_release_from_contiguous(dev, page,
> +						    size >> PAGE_SHIFT);
> +			return NULL;
> +		}
> +		addr = dma_common_contiguous_remap(page, size, VM_USERMAP,
> +						   prot,
> +						   __builtin_return_address(0));
> +		if (addr) {
> +			if (!coherent)
> +				arch_dma_prep_coherent(page, iosize);
> +			memset(addr, 0, size);
> +		} else {
> +			__iommu_dma_unmap_page(dev, *handle, iosize, 0, attrs);
> +			dma_release_from_contiguous(dev, page,
> +						    size >> PAGE_SHIFT);
> +		}
> +	} else {
> +		pgprot_t prot = arch_dma_mmap_pgprot(dev, PAGE_KERNEL, attrs);
> +		struct page **pages;
> +
> +		pages = __iommu_dma_alloc(dev, iosize, gfp, attrs, ioprot,
> +					handle);
> +		if (!pages)
> +			return NULL;
> +
> +		addr = dma_common_pages_remap(pages, size, VM_USERMAP, prot,
> +					      __builtin_return_address(0));
> +		if (!addr)
> +			__iommu_dma_free(dev, pages, iosize, handle);
> +	}
> +	return addr;
> +}
> +
> +static void iommu_dma_free(struct device *dev, size_t size, void *cpu_addr,
> +		dma_addr_t handle, unsigned long attrs)
> +{
> +	size_t iosize = size;
> +
> +	size = PAGE_ALIGN(size);
> +	/*
> +	 * @cpu_addr will be one of 4 things depending on how it was allocated:
> +	 * - A remapped array of pages for contiguous allocations.
> +	 * - A remapped array of pages from __iommu_dma_alloc(), for all
> +	 *   non-atomic allocations.
> +	 * - A non-cacheable alias from the atomic pool, for atomic
> +	 *   allocations by non-coherent devices.
> +	 * - A normal lowmem address, for atomic allocations by
> +	 *   coherent devices.
> +	 * Hence how dodgy the below logic looks...
> +	 */
> +	if (dma_in_atomic_pool(cpu_addr, size)) {
> +		__iommu_dma_unmap_page(dev, handle, iosize, 0, 0);
> +		dma_free_from_pool(cpu_addr, size);
> +	} else if (attrs & DMA_ATTR_FORCE_CONTIGUOUS) {
> +		struct page *page = vmalloc_to_page(cpu_addr);
> +
> +		__iommu_dma_unmap_page(dev, handle, iosize, 0, attrs);
> +		dma_release_from_contiguous(dev, page, size >> PAGE_SHIFT);
> +		dma_common_free_remap(cpu_addr, size, VM_USERMAP);
> +	} else if (is_vmalloc_addr(cpu_addr)){
> +		struct vm_struct *area = find_vm_area(cpu_addr);
> +
> +		if (WARN_ON(!area || !area->pages))
> +			return;
> +		__iommu_dma_free(dev, area->pages, iosize, &handle);
> +		dma_common_free_remap(cpu_addr, size, VM_USERMAP);
> +	} else {
> +		__iommu_dma_unmap_page(dev, handle, iosize, 0, 0);
> +		__free_pages(virt_to_page(cpu_addr), get_order(size));
> +	}
> +}
> +
> +static int __iommu_dma_mmap_pfn(struct vm_area_struct *vma,
> +			      unsigned long pfn, size_t size)
> +{
> +	return remap_pfn_range(vma, vma->vm_start, pfn + vma->vm_pgoff,
> +			       vma->vm_end - vma->vm_start,
> +			       vma->vm_page_prot);
> +}
> +
> +static int iommu_dma_mmap(struct device *dev, struct vm_area_struct *vma,
> +		void *cpu_addr, dma_addr_t dma_addr, size_t size,
> +		unsigned long attrs)
> +{
> +	unsigned long nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
> +	unsigned long off = vma->vm_pgoff;
> +	struct vm_struct *area;
> +	int ret;
> +
> +	vma->vm_page_prot = arch_dma_mmap_pgprot(dev, vma->vm_page_prot, attrs);
> +
> +	if (dma_mmap_from_dev_coherent(dev, vma, cpu_addr, size, &ret))
> +		return ret;
> +
> +	if (off >= nr_pages || vma_pages(vma) > nr_pages - off)
> +		return -ENXIO;
> +
> +	if (!is_vmalloc_addr(cpu_addr)) {
> +		unsigned long pfn = page_to_pfn(virt_to_page(cpu_addr));
> +		return __iommu_dma_mmap_pfn(vma, pfn, size);
> +	}
> +
> +	if (attrs & DMA_ATTR_FORCE_CONTIGUOUS) {
> +		/*
> +		 * DMA_ATTR_FORCE_CONTIGUOUS allocations are always remapped,
> +		 * hence in the vmalloc space.
> +		 */
> +		unsigned long pfn = vmalloc_to_pfn(cpu_addr);
> +		return __iommu_dma_mmap_pfn(vma, pfn, size);
> +	}
> +
> +	area = find_vm_area(cpu_addr);
> +	if (WARN_ON(!area || !area->pages))
> +		return -ENXIO;
> +
> +	return __iommu_dma_mmap(area->pages, size, vma);
> +}
> +
> +static int __iommu_dma_get_sgtable_page(struct sg_table *sgt, struct page *page,
> +		size_t size)
> +{
> +	int ret = sg_alloc_table(sgt, 1, GFP_KERNEL);
> +
> +	if (!ret)
> +		sg_set_page(sgt->sgl, page, PAGE_ALIGN(size), 0);
> +	return ret;
> +}
> +
> +static int iommu_dma_get_sgtable(struct device *dev, struct sg_table *sgt,
> +		void *cpu_addr, dma_addr_t dma_addr, size_t size,
> +		unsigned long attrs)
> +{
> +	unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
> +	struct vm_struct *area = find_vm_area(cpu_addr);
> +
> +	if (!is_vmalloc_addr(cpu_addr)) {
> +		struct page *page = virt_to_page(cpu_addr);
> +		return __iommu_dma_get_sgtable_page(sgt, page, size);
> +	}
> +
> +	if (attrs & DMA_ATTR_FORCE_CONTIGUOUS) {
> +		/*
> +		 * DMA_ATTR_FORCE_CONTIGUOUS allocations are always remapped,
> +		 * hence in the vmalloc space.
> +		 */
> +		struct page *page = vmalloc_to_page(cpu_addr);
> +		return __iommu_dma_get_sgtable_page(sgt, page, size);
> +	}
> +
> +	if (WARN_ON(!area || !area->pages))
> +		return -ENXIO;
> +
> +	return sg_alloc_table_from_pages(sgt, area->pages, count, 0, size,
> +					 GFP_KERNEL);
> +}
> +
> +static const struct dma_map_ops iommu_dma_ops = {
> +	.alloc			= iommu_dma_alloc,
> +	.free			= iommu_dma_free,
> +	.mmap			= iommu_dma_mmap,
> +	.get_sgtable		= iommu_dma_get_sgtable,
> +	.map_page		= iommu_dma_map_page,
> +	.unmap_page		= iommu_dma_unmap_page,
> +	.map_sg			= iommu_dma_map_sg,
> +	.unmap_sg		= iommu_dma_unmap_sg,
> +	.sync_single_for_cpu	= iommu_dma_sync_single_for_cpu,
> +	.sync_single_for_device	= iommu_dma_sync_single_for_device,
> +	.sync_sg_for_cpu	= iommu_dma_sync_sg_for_cpu,
> +	.sync_sg_for_device	= iommu_dma_sync_sg_for_device,
> +	.map_resource		= iommu_dma_map_resource,
> +	.unmap_resource		= iommu_dma_unmap_resource,
> +};
> +
> +/*
> + * The IOMMU core code allocates the default DMA domain, which the underlying
> + * IOMMU driver needs to support via the dma-iommu layer.
> + */
> +void iommu_setup_dma_ops(struct device *dev, u64 dma_base, u64 size)
> +{
> +	struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
> +
> +	if (!domain)
> +		goto out_err;
> +
> +	/*
> +	 * The IOMMU core code allocates the default DMA domain, which the
> +	 * underlying IOMMU driver needs to support via the dma-iommu layer.
> +	 */
> +	if (domain->type == IOMMU_DOMAIN_DMA) {
> +		if (iommu_dma_init_domain(domain, dma_base, size, dev))
> +			goto out_err;
> +		dev->dma_ops = &iommu_dma_ops;
> +	}
> +
> +	return;
> +out_err:
> +	 pr_warn("Failed to set up IOMMU for device %s; retaining platform DMA ops\n",
> +		 dev_name(dev));
> +}
> +
>   static struct iommu_dma_msi_page *iommu_dma_get_msi_page(struct device *dev,
>   		phys_addr_t msi_addr, struct iommu_domain *domain)
>   {
> @@ -921,3 +1247,9 @@ void iommu_dma_map_msi_msg(int irq, struct msi_msg *msg)
>   		msg->address_lo += lower_32_bits(msi_page->iova);
>   	}
>   }
> +
> +static int iommu_dma_init(void)
> +{
> +	return iova_cache_get();
> +}
> +arch_initcall(iommu_dma_init);
> diff --git a/include/linux/dma-iommu.h b/include/linux/dma-iommu.h
> index 3216447178a7..dadf4383f555 100644
> --- a/include/linux/dma-iommu.h
> +++ b/include/linux/dma-iommu.h
> @@ -24,49 +24,13 @@
>   #include <linux/iommu.h>
>   #include <linux/msi.h>
>   
> -int iommu_dma_init(void);
> -
>   /* Domain management interface for IOMMU drivers */
>   int iommu_get_dma_cookie(struct iommu_domain *domain);
>   int iommu_get_msi_cookie(struct iommu_domain *domain, dma_addr_t base);
>   void iommu_put_dma_cookie(struct iommu_domain *domain);
>   
>   /* Setup call for arch DMA mapping code */
> -int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base,
> -		u64 size, struct device *dev);
> -
> -/* General helpers for DMA-API <-> IOMMU-API interaction */
> -int dma_info_to_prot(enum dma_data_direction dir, bool coherent,
> -		     unsigned long attrs);
> -
> -/*
> - * These implement the bulk of the relevant DMA mapping callbacks, but require
> - * the arch code to take care of attributes and cache maintenance
> - */
> -struct page **iommu_dma_alloc(struct device *dev, size_t size, gfp_t gfp,
> -		unsigned long attrs, int prot, dma_addr_t *handle);
> -void iommu_dma_free(struct device *dev, struct page **pages, size_t size,
> -		dma_addr_t *handle);
> -
> -int iommu_dma_mmap(struct page **pages, size_t size, struct vm_area_struct *vma);
> -
> -dma_addr_t iommu_dma_map_page(struct device *dev, struct page *page,
> -		unsigned long offset, size_t size, int prot);
> -int iommu_dma_map_sg(struct device *dev, struct scatterlist *sg,
> -		int nents, int prot);
> -
> -/*
> - * Arch code with no special attribute handling may use these
> - * directly as DMA mapping callbacks for simplicity
> - */
> -void iommu_dma_unmap_page(struct device *dev, dma_addr_t handle, size_t size,
> -		enum dma_data_direction dir, unsigned long attrs);
> -void iommu_dma_unmap_sg(struct device *dev, struct scatterlist *sg, int nents,
> -		enum dma_data_direction dir, unsigned long attrs);
> -dma_addr_t iommu_dma_map_resource(struct device *dev, phys_addr_t phys,
> -		size_t size, enum dma_data_direction dir, unsigned long attrs);
> -void iommu_dma_unmap_resource(struct device *dev, dma_addr_t handle,
> -		size_t size, enum dma_data_direction dir, unsigned long attrs);
> +void iommu_setup_dma_ops(struct device *dev, u64 dma_base, u64 size);
>   
>   /* The DMA API isn't _quite_ the whole story, though... */
>   void iommu_dma_map_msi_msg(int irq, struct msi_msg *msg);
> @@ -75,12 +39,13 @@ void iommu_dma_get_resv_regions(struct device *dev, struct list_head *list);
>   #else /* CONFIG_IOMMU_DMA */
>   
>   struct iommu_domain;
> +struct iommu_ops;
>   struct msi_msg;
>   struct device;
>   
> -static inline int iommu_dma_init(void)
> +static inline void iommu_setup_dma_ops(struct device *dev, u64 dma_base,
> +		u64 size)
>   {
> -	return 0;
>   }
>   
>   static inline int iommu_get_dma_cookie(struct iommu_domain *domain)
>
Jon Hunter June 3, 2019, 7:47 p.m. UTC | #2
On 29/04/2019 13:56, Robin Murphy wrote:
> On 22/04/2019 18:59, Christoph Hellwig wrote:
>> There is nothing really arm64 specific in the iommu_dma_ops
>> implementation, so move it to dma-iommu.c and keep a lot of symbols
>> self-contained.  Note the implementation does depend on the
>> DMA_DIRECT_REMAP infrastructure for now, so we'll have to make the
>> DMA_IOMMU support depend on it, but this will be relaxed soon.
> 
> Nothing looks objectionable, and boot testing with this much of the
> series merged has my coherent and non-coherent IOMMU-backed devices
> appearing to still work OK, so:
> 
> Acked-by: Robin Murphy <robin.murphy@arm.com>

Since next-20190529 one of our tests for MMC has started failing, where
the symptom is that the data written to the MMC does not match the
source. Bisecting this is pointing to this commit. Unfortunately, I am
not able to cleanly revert this on top of -next, but wanted to report
this if case you have any ideas.

Cheers
Jon
hch@lst.de June 4, 2019, 6:05 a.m. UTC | #3
On Mon, Jun 03, 2019 at 08:47:57PM +0100, Jon Hunter wrote:
> Since next-20190529 one of our tests for MMC has started failing, where
> the symptom is that the data written to the MMC does not match the
> source. Bisecting this is pointing to this commit. Unfortunately, I am
> not able to cleanly revert this on top of -next, but wanted to report
> this if case you have any ideas.

Does this fix your problem?

https://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu.git/commit/?h=generic-dma-ops&id=1b961423158caaae49d3900b7c9c37477bbfa9b3
Jon Hunter June 4, 2019, 11:35 a.m. UTC | #4
On 04/06/2019 07:05, Christoph Hellwig wrote:
> On Mon, Jun 03, 2019 at 08:47:57PM +0100, Jon Hunter wrote:
>> Since next-20190529 one of our tests for MMC has started failing, where
>> the symptom is that the data written to the MMC does not match the
>> source. Bisecting this is pointing to this commit. Unfortunately, I am
>> not able to cleanly revert this on top of -next, but wanted to report
>> this if case you have any ideas.
> 
> Does this fix your problem?
> 
> https://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu.git/commit/?h=generic-dma-ops&id=1b961423158caaae49d3900b7c9c37477bbfa9b3

Yes I can confirm with this patch on today's -next the issue is no
longer seen, and reverting this patch on top of today's -next causes the
problem to occur again. So yes this fixes my problem.

Thanks!
Jon

Patch
diff mbox series

diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c
index 636fa7c64370..d1661f78eb4d 100644
--- a/arch/arm64/mm/dma-mapping.c
+++ b/arch/arm64/mm/dma-mapping.c
@@ -27,6 +27,7 @@ 
 #include <linux/dma-direct.h>
 #include <linux/dma-noncoherent.h>
 #include <linux/dma-contiguous.h>
+#include <linux/dma-iommu.h>
 #include <linux/vmalloc.h>
 #include <linux/swiotlb.h>
 #include <linux/pci.h>
@@ -58,27 +59,6 @@  void arch_dma_prep_coherent(struct page *page, size_t size)
 	__dma_flush_area(page_address(page), size);
 }
 
-#ifdef CONFIG_IOMMU_DMA
-static int __swiotlb_get_sgtable_page(struct sg_table *sgt,
-				      struct page *page, size_t size)
-{
-	int ret = sg_alloc_table(sgt, 1, GFP_KERNEL);
-
-	if (!ret)
-		sg_set_page(sgt->sgl, page, PAGE_ALIGN(size), 0);
-
-	return ret;
-}
-
-static int __swiotlb_mmap_pfn(struct vm_area_struct *vma,
-			      unsigned long pfn, size_t size)
-{
-	return remap_pfn_range(vma, vma->vm_start, pfn + vma->vm_pgoff,
-			      vma->vm_end - vma->vm_start,
-			      vma->vm_page_prot);
-}
-#endif /* CONFIG_IOMMU_DMA */
-
 static int __init arm64_dma_init(void)
 {
 	WARN_TAINT(ARCH_DMA_MINALIGN < cache_line_size(),
@@ -90,379 +70,18 @@  static int __init arm64_dma_init(void)
 arch_initcall(arm64_dma_init);
 
 #ifdef CONFIG_IOMMU_DMA
-#include <linux/dma-iommu.h>
-#include <linux/platform_device.h>
-#include <linux/amba/bus.h>
-
-static void *__iommu_alloc_attrs(struct device *dev, size_t size,
-				 dma_addr_t *handle, gfp_t gfp,
-				 unsigned long attrs)
-{
-	bool coherent = dev_is_dma_coherent(dev);
-	int ioprot = dma_info_to_prot(DMA_BIDIRECTIONAL, coherent, attrs);
-	size_t iosize = size;
-	void *addr;
-
-	if (WARN(!dev, "cannot create IOMMU mapping for unknown device\n"))
-		return NULL;
-
-	size = PAGE_ALIGN(size);
-
-	/*
-	 * Some drivers rely on this, and we probably don't want the
-	 * possibility of stale kernel data being read by devices anyway.
-	 */
-	gfp |= __GFP_ZERO;
-
-	if (!gfpflags_allow_blocking(gfp)) {
-		struct page *page;
-		/*
-		 * In atomic context we can't remap anything, so we'll only
-		 * get the virtually contiguous buffer we need by way of a
-		 * physically contiguous allocation.
-		 */
-		if (coherent) {
-			page = alloc_pages(gfp, get_order(size));
-			addr = page ? page_address(page) : NULL;
-		} else {
-			addr = dma_alloc_from_pool(size, &page, gfp);
-		}
-		if (!addr)
-			return NULL;
-
-		*handle = iommu_dma_map_page(dev, page, 0, iosize, ioprot);
-		if (*handle == DMA_MAPPING_ERROR) {
-			if (coherent)
-				__free_pages(page, get_order(size));
-			else
-				dma_free_from_pool(addr, size);
-			addr = NULL;
-		}
-	} else if (attrs & DMA_ATTR_FORCE_CONTIGUOUS) {
-		pgprot_t prot = arch_dma_mmap_pgprot(dev, PAGE_KERNEL, attrs);
-		struct page *page;
-
-		page = dma_alloc_from_contiguous(dev, size >> PAGE_SHIFT,
-					get_order(size), gfp & __GFP_NOWARN);
-		if (!page)
-			return NULL;
-
-		*handle = iommu_dma_map_page(dev, page, 0, iosize, ioprot);
-		if (*handle == DMA_MAPPING_ERROR) {
-			dma_release_from_contiguous(dev, page,
-						    size >> PAGE_SHIFT);
-			return NULL;
-		}
-		addr = dma_common_contiguous_remap(page, size, VM_USERMAP,
-						   prot,
-						   __builtin_return_address(0));
-		if (addr) {
-			if (!coherent)
-				__dma_flush_area(page_to_virt(page), iosize);
-			memset(addr, 0, size);
-		} else {
-			iommu_dma_unmap_page(dev, *handle, iosize, 0, attrs);
-			dma_release_from_contiguous(dev, page,
-						    size >> PAGE_SHIFT);
-		}
-	} else {
-		pgprot_t prot = arch_dma_mmap_pgprot(dev, PAGE_KERNEL, attrs);
-		struct page **pages;
-
-		pages = iommu_dma_alloc(dev, iosize, gfp, attrs, ioprot,
-					handle);
-		if (!pages)
-			return NULL;
-
-		addr = dma_common_pages_remap(pages, size, VM_USERMAP, prot,
-					      __builtin_return_address(0));
-		if (!addr)
-			iommu_dma_free(dev, pages, iosize, handle);
-	}
-	return addr;
-}
-
-static void __iommu_free_attrs(struct device *dev, size_t size, void *cpu_addr,
-			       dma_addr_t handle, unsigned long attrs)
-{
-	size_t iosize = size;
-
-	size = PAGE_ALIGN(size);
-	/*
-	 * @cpu_addr will be one of 4 things depending on how it was allocated:
-	 * - A remapped array of pages for contiguous allocations.
-	 * - A remapped array of pages from iommu_dma_alloc(), for all
-	 *   non-atomic allocations.
-	 * - A non-cacheable alias from the atomic pool, for atomic
-	 *   allocations by non-coherent devices.
-	 * - A normal lowmem address, for atomic allocations by
-	 *   coherent devices.
-	 * Hence how dodgy the below logic looks...
-	 */
-	if (dma_in_atomic_pool(cpu_addr, size)) {
-		iommu_dma_unmap_page(dev, handle, iosize, 0, 0);
-		dma_free_from_pool(cpu_addr, size);
-	} else if (attrs & DMA_ATTR_FORCE_CONTIGUOUS) {
-		struct page *page = vmalloc_to_page(cpu_addr);
-
-		iommu_dma_unmap_page(dev, handle, iosize, 0, attrs);
-		dma_release_from_contiguous(dev, page, size >> PAGE_SHIFT);
-		dma_common_free_remap(cpu_addr, size, VM_USERMAP);
-	} else if (is_vmalloc_addr(cpu_addr)){
-		struct vm_struct *area = find_vm_area(cpu_addr);
-
-		if (WARN_ON(!area || !area->pages))
-			return;
-		iommu_dma_free(dev, area->pages, iosize, &handle);
-		dma_common_free_remap(cpu_addr, size, VM_USERMAP);
-	} else {
-		iommu_dma_unmap_page(dev, handle, iosize, 0, 0);
-		__free_pages(virt_to_page(cpu_addr), get_order(size));
-	}
-}
-
-static int __iommu_mmap_attrs(struct device *dev, struct vm_area_struct *vma,
-			      void *cpu_addr, dma_addr_t dma_addr, size_t size,
-			      unsigned long attrs)
-{
-	unsigned long nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
-	unsigned long off = vma->vm_pgoff;
-	struct vm_struct *area;
-	int ret;
-
-	vma->vm_page_prot = arch_dma_mmap_pgprot(dev, vma->vm_page_prot, attrs);
-
-	if (dma_mmap_from_dev_coherent(dev, vma, cpu_addr, size, &ret))
-		return ret;
-
-	if (off >= nr_pages || vma_pages(vma) > nr_pages - off)
-		return -ENXIO;
-
-	if (!is_vmalloc_addr(cpu_addr)) {
-		unsigned long pfn = page_to_pfn(virt_to_page(cpu_addr));
-		return __swiotlb_mmap_pfn(vma, pfn, size);
-	}
-
-	if (attrs & DMA_ATTR_FORCE_CONTIGUOUS) {
-		/*
-		 * DMA_ATTR_FORCE_CONTIGUOUS allocations are always remapped,
-		 * hence in the vmalloc space.
-		 */
-		unsigned long pfn = vmalloc_to_pfn(cpu_addr);
-		return __swiotlb_mmap_pfn(vma, pfn, size);
-	}
-
-	area = find_vm_area(cpu_addr);
-	if (WARN_ON(!area || !area->pages))
-		return -ENXIO;
-
-	return iommu_dma_mmap(area->pages, size, vma);
-}
-
-static int __iommu_get_sgtable(struct device *dev, struct sg_table *sgt,
-			       void *cpu_addr, dma_addr_t dma_addr,
-			       size_t size, unsigned long attrs)
-{
-	unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
-	struct vm_struct *area = find_vm_area(cpu_addr);
-
-	if (!is_vmalloc_addr(cpu_addr)) {
-		struct page *page = virt_to_page(cpu_addr);
-		return __swiotlb_get_sgtable_page(sgt, page, size);
-	}
-
-	if (attrs & DMA_ATTR_FORCE_CONTIGUOUS) {
-		/*
-		 * DMA_ATTR_FORCE_CONTIGUOUS allocations are always remapped,
-		 * hence in the vmalloc space.
-		 */
-		struct page *page = vmalloc_to_page(cpu_addr);
-		return __swiotlb_get_sgtable_page(sgt, page, size);
-	}
-
-	if (WARN_ON(!area || !area->pages))
-		return -ENXIO;
-
-	return sg_alloc_table_from_pages(sgt, area->pages, count, 0, size,
-					 GFP_KERNEL);
-}
-
-static void __iommu_sync_single_for_cpu(struct device *dev,
-					dma_addr_t dev_addr, size_t size,
-					enum dma_data_direction dir)
-{
-	phys_addr_t phys;
-
-	if (dev_is_dma_coherent(dev))
-		return;
-
-	phys = iommu_iova_to_phys(iommu_get_dma_domain(dev), dev_addr);
-	arch_sync_dma_for_cpu(dev, phys, size, dir);
-}
-
-static void __iommu_sync_single_for_device(struct device *dev,
-					   dma_addr_t dev_addr, size_t size,
-					   enum dma_data_direction dir)
-{
-	phys_addr_t phys;
-
-	if (dev_is_dma_coherent(dev))
-		return;
-
-	phys = iommu_iova_to_phys(iommu_get_dma_domain(dev), dev_addr);
-	arch_sync_dma_for_device(dev, phys, size, dir);
-}
-
-static dma_addr_t __iommu_map_page(struct device *dev, struct page *page,
-				   unsigned long offset, size_t size,
-				   enum dma_data_direction dir,
-				   unsigned long attrs)
-{
-	bool coherent = dev_is_dma_coherent(dev);
-	int prot = dma_info_to_prot(dir, coherent, attrs);
-	dma_addr_t dev_addr = iommu_dma_map_page(dev, page, offset, size, prot);
-
-	if (!coherent && !(attrs & DMA_ATTR_SKIP_CPU_SYNC) &&
-	    dev_addr != DMA_MAPPING_ERROR)
-		__dma_map_area(page_address(page) + offset, size, dir);
-
-	return dev_addr;
-}
-
-static void __iommu_unmap_page(struct device *dev, dma_addr_t dev_addr,
-			       size_t size, enum dma_data_direction dir,
-			       unsigned long attrs)
-{
-	if ((attrs & DMA_ATTR_SKIP_CPU_SYNC) == 0)
-		__iommu_sync_single_for_cpu(dev, dev_addr, size, dir);
-
-	iommu_dma_unmap_page(dev, dev_addr, size, dir, attrs);
-}
-
-static void __iommu_sync_sg_for_cpu(struct device *dev,
-				    struct scatterlist *sgl, int nelems,
-				    enum dma_data_direction dir)
-{
-	struct scatterlist *sg;
-	int i;
-
-	if (dev_is_dma_coherent(dev))
-		return;
-
-	for_each_sg(sgl, sg, nelems, i)
-		arch_sync_dma_for_cpu(dev, sg_phys(sg), sg->length, dir);
-}
-
-static void __iommu_sync_sg_for_device(struct device *dev,
-				       struct scatterlist *sgl, int nelems,
-				       enum dma_data_direction dir)
-{
-	struct scatterlist *sg;
-	int i;
-
-	if (dev_is_dma_coherent(dev))
-		return;
-
-	for_each_sg(sgl, sg, nelems, i)
-		arch_sync_dma_for_device(dev, sg_phys(sg), sg->length, dir);
-}
-
-static int __iommu_map_sg_attrs(struct device *dev, struct scatterlist *sgl,
-				int nelems, enum dma_data_direction dir,
-				unsigned long attrs)
-{
-	bool coherent = dev_is_dma_coherent(dev);
-
-	if ((attrs & DMA_ATTR_SKIP_CPU_SYNC) == 0)
-		__iommu_sync_sg_for_device(dev, sgl, nelems, dir);
-
-	return iommu_dma_map_sg(dev, sgl, nelems,
-				dma_info_to_prot(dir, coherent, attrs));
-}
-
-static void __iommu_unmap_sg_attrs(struct device *dev,
-				   struct scatterlist *sgl, int nelems,
-				   enum dma_data_direction dir,
-				   unsigned long attrs)
-{
-	if ((attrs & DMA_ATTR_SKIP_CPU_SYNC) == 0)
-		__iommu_sync_sg_for_cpu(dev, sgl, nelems, dir);
-
-	iommu_dma_unmap_sg(dev, sgl, nelems, dir, attrs);
-}
-
-static const struct dma_map_ops iommu_dma_ops = {
-	.alloc = __iommu_alloc_attrs,
-	.free = __iommu_free_attrs,
-	.mmap = __iommu_mmap_attrs,
-	.get_sgtable = __iommu_get_sgtable,
-	.map_page = __iommu_map_page,
-	.unmap_page = __iommu_unmap_page,
-	.map_sg = __iommu_map_sg_attrs,
-	.unmap_sg = __iommu_unmap_sg_attrs,
-	.sync_single_for_cpu = __iommu_sync_single_for_cpu,
-	.sync_single_for_device = __iommu_sync_single_for_device,
-	.sync_sg_for_cpu = __iommu_sync_sg_for_cpu,
-	.sync_sg_for_device = __iommu_sync_sg_for_device,
-	.map_resource = iommu_dma_map_resource,
-	.unmap_resource = iommu_dma_unmap_resource,
-};
-
-static int __init __iommu_dma_init(void)
-{
-	return iommu_dma_init();
-}
-arch_initcall(__iommu_dma_init);
-
-static void __iommu_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
-				  const struct iommu_ops *ops)
-{
-	struct iommu_domain *domain;
-
-	if (!ops)
-		return;
-
-	/*
-	 * The IOMMU core code allocates the default DMA domain, which the
-	 * underlying IOMMU driver needs to support via the dma-iommu layer.
-	 */
-	domain = iommu_get_domain_for_dev(dev);
-
-	if (!domain)
-		goto out_err;
-
-	if (domain->type == IOMMU_DOMAIN_DMA) {
-		if (iommu_dma_init_domain(domain, dma_base, size, dev))
-			goto out_err;
-
-		dev->dma_ops = &iommu_dma_ops;
-	}
-
-	return;
-
-out_err:
-	 pr_warn("Failed to set up IOMMU for device %s; retaining platform DMA ops\n",
-		 dev_name(dev));
-}
-
 void arch_teardown_dma_ops(struct device *dev)
 {
 	dev->dma_ops = NULL;
 }
-
-#else
-
-static void __iommu_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
-				  const struct iommu_ops *iommu)
-{ }
-
-#endif  /* CONFIG_IOMMU_DMA */
+#endif
 
 void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
 			const struct iommu_ops *iommu, bool coherent)
 {
 	dev->dma_coherent = coherent;
-	__iommu_setup_dma_ops(dev, dma_base, size, iommu);
+	if (iommu)
+		iommu_setup_dma_ops(dev, dma_base, size);
 
 #ifdef CONFIG_XEN
 	if (xen_initial_domain())
diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
index 6f07f3b21816..bdc14baf2ee5 100644
--- a/drivers/iommu/Kconfig
+++ b/drivers/iommu/Kconfig
@@ -95,6 +95,7 @@  config IOMMU_DMA
 	select IOMMU_API
 	select IOMMU_IOVA
 	select NEED_SG_DMA_LENGTH
+	depends on DMA_DIRECT_REMAP
 
 config FSL_PAMU
 	bool "Freescale IOMMU support"
diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index f915cb7c46e6..622123551bba 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -21,6 +21,7 @@ 
 
 #include <linux/acpi_iort.h>
 #include <linux/device.h>
+#include <linux/dma-contiguous.h>
 #include <linux/dma-iommu.h>
 #include <linux/dma-noncoherent.h>
 #include <linux/gfp.h>
@@ -79,11 +80,6 @@  static struct iommu_dma_cookie *cookie_alloc(enum iommu_dma_cookie_type type)
 	return cookie;
 }
 
-int iommu_dma_init(void)
-{
-	return iova_cache_get();
-}
-
 /**
  * iommu_get_dma_cookie - Acquire DMA-API resources for a domain
  * @domain: IOMMU domain to prepare for DMA-API usage
@@ -285,7 +281,7 @@  static void iommu_dma_flush_iotlb_all(struct iova_domain *iovad)
  * to ensure it is an invalid IOVA. It is safe to reinitialise a domain, but
  * any change which could make prior IOVAs invalid will fail.
  */
-int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base,
+static int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base,
 		u64 size, struct device *dev)
 {
 	struct iommu_dma_cookie *cookie = domain->iova_cookie;
@@ -336,7 +332,6 @@  int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base,
 
 	return iova_reserve_iommu_regions(dev, domain);
 }
-EXPORT_SYMBOL(iommu_dma_init_domain);
 
 /**
  * dma_info_to_prot - Translate DMA API directions and attributes to IOMMU API
@@ -347,7 +342,7 @@  EXPORT_SYMBOL(iommu_dma_init_domain);
  *
  * Return: corresponding IOMMU API page protection flags
  */
-int dma_info_to_prot(enum dma_data_direction dir, bool coherent,
+static int dma_info_to_prot(enum dma_data_direction dir, bool coherent,
 		     unsigned long attrs)
 {
 	int prot = coherent ? IOMMU_CACHE : 0;
@@ -506,17 +501,17 @@  static struct page **__iommu_dma_alloc_pages(struct device *dev,
 }
 
 /**
- * iommu_dma_free - Free a buffer allocated by iommu_dma_alloc()
+ * iommu_dma_free - Free a buffer allocated by __iommu_dma_alloc()
  * @dev: Device which owns this buffer
- * @pages: Array of buffer pages as returned by iommu_dma_alloc()
+ * @pages: Array of buffer pages as returned by __iommu_dma_alloc()
  * @size: Size of buffer in bytes
  * @handle: DMA address of buffer
  *
  * Frees both the pages associated with the buffer, and the array
  * describing them
  */
-void iommu_dma_free(struct device *dev, struct page **pages, size_t size,
-		dma_addr_t *handle)
+static void __iommu_dma_free(struct device *dev, struct page **pages,
+		size_t size, dma_addr_t *handle)
 {
 	__iommu_dma_unmap(iommu_get_dma_domain(dev), *handle, size);
 	__iommu_dma_free_pages(pages, PAGE_ALIGN(size) >> PAGE_SHIFT);
@@ -524,7 +519,7 @@  void iommu_dma_free(struct device *dev, struct page **pages, size_t size,
 }
 
 /**
- * iommu_dma_alloc - Allocate and map a buffer contiguous in IOVA space
+ * __iommu_dma_alloc - Allocate and map a buffer contiguous in IOVA space
  * @dev: Device to allocate memory for. Must be a real device
  *	 attached to an iommu_dma_domain
  * @size: Size of buffer in bytes
@@ -539,8 +534,8 @@  void iommu_dma_free(struct device *dev, struct page **pages, size_t size,
  * Return: Array of struct page pointers describing the buffer,
  *	   or NULL on failure.
  */
-struct page **iommu_dma_alloc(struct device *dev, size_t size, gfp_t gfp,
-		unsigned long attrs, int prot, dma_addr_t *handle)
+static struct page **__iommu_dma_alloc(struct device *dev, size_t size,
+		gfp_t gfp, unsigned long attrs, int prot, dma_addr_t *handle)
 {
 	struct iommu_domain *domain = iommu_get_dma_domain(dev);
 	struct iommu_dma_cookie *cookie = domain->iova_cookie;
@@ -602,16 +597,16 @@  struct page **iommu_dma_alloc(struct device *dev, size_t size, gfp_t gfp,
 }
 
 /**
- * iommu_dma_mmap - Map a buffer into provided user VMA
- * @pages: Array representing buffer from iommu_dma_alloc()
+ * __iommu_dma_mmap - Map a buffer into provided user VMA
+ * @pages: Array representing buffer from __iommu_dma_alloc()
  * @size: Size of buffer in bytes
  * @vma: VMA describing requested userspace mapping
  *
  * Maps the pages of the buffer in @pages into @vma. The caller is responsible
  * for verifying the correct size and protection of @vma beforehand.
  */
-
-int iommu_dma_mmap(struct page **pages, size_t size, struct vm_area_struct *vma)
+static int __iommu_dma_mmap(struct page **pages, size_t size,
+		struct vm_area_struct *vma)
 {
 	unsigned long uaddr = vma->vm_start;
 	unsigned int i, count = PAGE_ALIGN(size) >> PAGE_SHIFT;
@@ -626,6 +621,58 @@  int iommu_dma_mmap(struct page **pages, size_t size, struct vm_area_struct *vma)
 	return ret;
 }
 
+static void iommu_dma_sync_single_for_cpu(struct device *dev,
+		dma_addr_t dma_handle, size_t size, enum dma_data_direction dir)
+{
+	phys_addr_t phys;
+
+	if (dev_is_dma_coherent(dev))
+		return;
+
+	phys = iommu_iova_to_phys(iommu_get_dma_domain(dev), dma_handle);
+	arch_sync_dma_for_cpu(dev, phys, size, dir);
+}
+
+static void iommu_dma_sync_single_for_device(struct device *dev,
+		dma_addr_t dma_handle, size_t size, enum dma_data_direction dir)
+{
+	phys_addr_t phys;
+
+	if (dev_is_dma_coherent(dev))
+		return;
+
+	phys = iommu_iova_to_phys(iommu_get_dma_domain(dev), dma_handle);
+	arch_sync_dma_for_device(dev, phys, size, dir);
+}
+
+static void iommu_dma_sync_sg_for_cpu(struct device *dev,
+		struct scatterlist *sgl, int nelems,
+		enum dma_data_direction dir)
+{
+	struct scatterlist *sg;
+	int i;
+
+	if (dev_is_dma_coherent(dev))
+		return;
+
+	for_each_sg(sgl, sg, nelems, i)
+		arch_sync_dma_for_cpu(dev, sg_phys(sg), sg->length, dir);
+}
+
+static void iommu_dma_sync_sg_for_device(struct device *dev,
+		struct scatterlist *sgl, int nelems,
+		enum dma_data_direction dir)
+{
+	struct scatterlist *sg;
+	int i;
+
+	if (dev_is_dma_coherent(dev))
+		return;
+
+	for_each_sg(sgl, sg, nelems, i)
+		arch_sync_dma_for_device(dev, sg_phys(sg), sg->length, dir);
+}
+
 static dma_addr_t __iommu_dma_map(struct device *dev, phys_addr_t phys,
 		size_t size, int prot, struct iommu_domain *domain)
 {
@@ -649,19 +696,44 @@  static dma_addr_t __iommu_dma_map(struct device *dev, phys_addr_t phys,
 	return iova + iova_off;
 }
 
-dma_addr_t iommu_dma_map_page(struct device *dev, struct page *page,
+static dma_addr_t __iommu_dma_map_page(struct device *dev, struct page *page,
 		unsigned long offset, size_t size, int prot)
 {
 	return __iommu_dma_map(dev, page_to_phys(page) + offset, size, prot,
 			iommu_get_dma_domain(dev));
 }
 
-void iommu_dma_unmap_page(struct device *dev, dma_addr_t handle, size_t size,
-		enum dma_data_direction dir, unsigned long attrs)
+static void __iommu_dma_unmap_page(struct device *dev, dma_addr_t handle,
+		size_t size, enum dma_data_direction dir, unsigned long attrs)
 {
 	__iommu_dma_unmap(iommu_get_dma_domain(dev), handle, size);
 }
 
+static dma_addr_t iommu_dma_map_page(struct device *dev, struct page *page,
+		unsigned long offset, size_t size, enum dma_data_direction dir,
+		unsigned long attrs)
+{
+	phys_addr_t phys = page_to_phys(page) + offset;
+	bool coherent = dev_is_dma_coherent(dev);
+	dma_addr_t dma_handle;
+
+	dma_handle =__iommu_dma_map(dev, phys, size,
+			dma_info_to_prot(dir, coherent, attrs),
+			iommu_get_dma_domain(dev));
+	if (!coherent && !(attrs & DMA_ATTR_SKIP_CPU_SYNC) &&
+	    dma_handle != DMA_MAPPING_ERROR)
+		arch_sync_dma_for_device(dev, phys, size, dir);
+	return dma_handle;
+}
+
+static void iommu_dma_unmap_page(struct device *dev, dma_addr_t dma_handle,
+		size_t size, enum dma_data_direction dir, unsigned long attrs)
+{
+	if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
+		iommu_dma_sync_single_for_cpu(dev, dma_handle, size, dir);
+	__iommu_dma_unmap(iommu_get_dma_domain(dev), dma_handle, size);
+}
+
 /*
  * Prepare a successfully-mapped scatterlist to give back to the caller.
  *
@@ -744,18 +816,22 @@  static void __invalidate_sg(struct scatterlist *sg, int nents)
  * impedance-matching, to be able to hand off a suitably-aligned list,
  * but still preserve the original offsets and sizes for the caller.
  */
-int iommu_dma_map_sg(struct device *dev, struct scatterlist *sg,
-		int nents, int prot)
+static int iommu_dma_map_sg(struct device *dev, struct scatterlist *sg,
+		int nents, enum dma_data_direction dir, unsigned long attrs)
 {
 	struct iommu_domain *domain = iommu_get_dma_domain(dev);
 	struct iommu_dma_cookie *cookie = domain->iova_cookie;
 	struct iova_domain *iovad = &cookie->iovad;
 	struct scatterlist *s, *prev = NULL;
+	int prot = dma_info_to_prot(dir, dev_is_dma_coherent(dev), attrs);
 	dma_addr_t iova;
 	size_t iova_len = 0;
 	unsigned long mask = dma_get_seg_boundary(dev);
 	int i;
 
+	if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
+		iommu_dma_sync_sg_for_device(dev, sg, nents, dir);
+
 	/*
 	 * Work out how much IOVA space we need, and align the segments to
 	 * IOVA granules for the IOMMU driver to handle. With some clever
@@ -815,12 +891,16 @@  int iommu_dma_map_sg(struct device *dev, struct scatterlist *sg,
 	return 0;
 }
 
-void iommu_dma_unmap_sg(struct device *dev, struct scatterlist *sg, int nents,
-		enum dma_data_direction dir, unsigned long attrs)
+static void iommu_dma_unmap_sg(struct device *dev, struct scatterlist *sg,
+		int nents, enum dma_data_direction dir, unsigned long attrs)
 {
 	dma_addr_t start, end;
 	struct scatterlist *tmp;
 	int i;
+
+	if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC) == 0)
+		iommu_dma_sync_sg_for_cpu(dev, sg, nents, dir);
+
 	/*
 	 * The scatterlist segments are mapped into a single
 	 * contiguous IOVA allocation, so this is incredibly easy.
@@ -835,7 +915,7 @@  void iommu_dma_unmap_sg(struct device *dev, struct scatterlist *sg, int nents,
 	__iommu_dma_unmap(iommu_get_dma_domain(dev), start, end - start);
 }
 
-dma_addr_t iommu_dma_map_resource(struct device *dev, phys_addr_t phys,
+static dma_addr_t iommu_dma_map_resource(struct device *dev, phys_addr_t phys,
 		size_t size, enum dma_data_direction dir, unsigned long attrs)
 {
 	return __iommu_dma_map(dev, phys, size,
@@ -843,12 +923,258 @@  dma_addr_t iommu_dma_map_resource(struct device *dev, phys_addr_t phys,
 			iommu_get_dma_domain(dev));
 }
 
-void iommu_dma_unmap_resource(struct device *dev, dma_addr_t handle,
+static void iommu_dma_unmap_resource(struct device *dev, dma_addr_t handle,
 		size_t size, enum dma_data_direction dir, unsigned long attrs)
 {
 	__iommu_dma_unmap(iommu_get_dma_domain(dev), handle, size);
 }
 
+static void *iommu_dma_alloc(struct device *dev, size_t size,
+		dma_addr_t *handle, gfp_t gfp, unsigned long attrs)
+{
+	bool coherent = dev_is_dma_coherent(dev);
+	int ioprot = dma_info_to_prot(DMA_BIDIRECTIONAL, coherent, attrs);
+	size_t iosize = size;
+	void *addr;
+
+	size = PAGE_ALIGN(size);
+	gfp |= __GFP_ZERO;
+
+	if (!gfpflags_allow_blocking(gfp)) {
+		struct page *page;
+		/*
+		 * In atomic context we can't remap anything, so we'll only
+		 * get the virtually contiguous buffer we need by way of a
+		 * physically contiguous allocation.
+		 */
+		if (coherent) {
+			page = alloc_pages(gfp, get_order(size));
+			addr = page ? page_address(page) : NULL;
+		} else {
+			addr = dma_alloc_from_pool(size, &page, gfp);
+		}
+		if (!addr)
+			return NULL;
+
+		*handle = __iommu_dma_map_page(dev, page, 0, iosize, ioprot);
+		if (*handle == DMA_MAPPING_ERROR) {
+			if (coherent)
+				__free_pages(page, get_order(size));
+			else
+				dma_free_from_pool(addr, size);
+			addr = NULL;
+		}
+	} else if (attrs & DMA_ATTR_FORCE_CONTIGUOUS) {
+		pgprot_t prot = arch_dma_mmap_pgprot(dev, PAGE_KERNEL, attrs);
+		struct page *page;
+
+		page = dma_alloc_from_contiguous(dev, size >> PAGE_SHIFT,
+					get_order(size), gfp & __GFP_NOWARN);
+		if (!page)
+			return NULL;
+
+		*handle = __iommu_dma_map_page(dev, page, 0, iosize, ioprot);
+		if (*handle == DMA_MAPPING_ERROR) {
+			dma_release_from_contiguous(dev, page,
+						    size >> PAGE_SHIFT);
+			return NULL;
+		}
+		addr = dma_common_contiguous_remap(page, size, VM_USERMAP,
+						   prot,
+						   __builtin_return_address(0));
+		if (addr) {
+			if (!coherent)
+				arch_dma_prep_coherent(page, iosize);
+			memset(addr, 0, size);
+		} else {
+			__iommu_dma_unmap_page(dev, *handle, iosize, 0, attrs);
+			dma_release_from_contiguous(dev, page,
+						    size >> PAGE_SHIFT);
+		}
+	} else {
+		pgprot_t prot = arch_dma_mmap_pgprot(dev, PAGE_KERNEL, attrs);
+		struct page **pages;
+
+		pages = __iommu_dma_alloc(dev, iosize, gfp, attrs, ioprot,
+					handle);
+		if (!pages)
+			return NULL;
+
+		addr = dma_common_pages_remap(pages, size, VM_USERMAP, prot,
+					      __builtin_return_address(0));
+		if (!addr)
+			__iommu_dma_free(dev, pages, iosize, handle);
+	}
+	return addr;
+}
+
+static void iommu_dma_free(struct device *dev, size_t size, void *cpu_addr,
+		dma_addr_t handle, unsigned long attrs)
+{
+	size_t iosize = size;
+
+	size = PAGE_ALIGN(size);
+	/*
+	 * @cpu_addr will be one of 4 things depending on how it was allocated:
+	 * - A remapped array of pages for contiguous allocations.
+	 * - A remapped array of pages from __iommu_dma_alloc(), for all
+	 *   non-atomic allocations.
+	 * - A non-cacheable alias from the atomic pool, for atomic
+	 *   allocations by non-coherent devices.
+	 * - A normal lowmem address, for atomic allocations by
+	 *   coherent devices.
+	 * Hence how dodgy the below logic looks...
+	 */
+	if (dma_in_atomic_pool(cpu_addr, size)) {
+		__iommu_dma_unmap_page(dev, handle, iosize, 0, 0);
+		dma_free_from_pool(cpu_addr, size);
+	} else if (attrs & DMA_ATTR_FORCE_CONTIGUOUS) {
+		struct page *page = vmalloc_to_page(cpu_addr);
+
+		__iommu_dma_unmap_page(dev, handle, iosize, 0, attrs);
+		dma_release_from_contiguous(dev, page, size >> PAGE_SHIFT);
+		dma_common_free_remap(cpu_addr, size, VM_USERMAP);
+	} else if (is_vmalloc_addr(cpu_addr)){
+		struct vm_struct *area = find_vm_area(cpu_addr);
+
+		if (WARN_ON(!area || !area->pages))
+			return;
+		__iommu_dma_free(dev, area->pages, iosize, &handle);
+		dma_common_free_remap(cpu_addr, size, VM_USERMAP);
+	} else {
+		__iommu_dma_unmap_page(dev, handle, iosize, 0, 0);
+		__free_pages(virt_to_page(cpu_addr), get_order(size));
+	}
+}
+
+static int __iommu_dma_mmap_pfn(struct vm_area_struct *vma,
+			      unsigned long pfn, size_t size)
+{
+	return remap_pfn_range(vma, vma->vm_start, pfn + vma->vm_pgoff,
+			       vma->vm_end - vma->vm_start,
+			       vma->vm_page_prot);
+}
+
+static int iommu_dma_mmap(struct device *dev, struct vm_area_struct *vma,
+		void *cpu_addr, dma_addr_t dma_addr, size_t size,
+		unsigned long attrs)
+{
+	unsigned long nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
+	unsigned long off = vma->vm_pgoff;
+	struct vm_struct *area;
+	int ret;
+
+	vma->vm_page_prot = arch_dma_mmap_pgprot(dev, vma->vm_page_prot, attrs);
+
+	if (dma_mmap_from_dev_coherent(dev, vma, cpu_addr, size, &ret))
+		return ret;
+
+	if (off >= nr_pages || vma_pages(vma) > nr_pages - off)
+		return -ENXIO;
+
+	if (!is_vmalloc_addr(cpu_addr)) {
+		unsigned long pfn = page_to_pfn(virt_to_page(cpu_addr));
+		return __iommu_dma_mmap_pfn(vma, pfn, size);
+	}
+
+	if (attrs & DMA_ATTR_FORCE_CONTIGUOUS) {
+		/*
+		 * DMA_ATTR_FORCE_CONTIGUOUS allocations are always remapped,
+		 * hence in the vmalloc space.
+		 */
+		unsigned long pfn = vmalloc_to_pfn(cpu_addr);
+		return __iommu_dma_mmap_pfn(vma, pfn, size);
+	}
+
+	area = find_vm_area(cpu_addr);
+	if (WARN_ON(!area || !area->pages))
+		return -ENXIO;
+
+	return __iommu_dma_mmap(area->pages, size, vma);
+}
+
+static int __iommu_dma_get_sgtable_page(struct sg_table *sgt, struct page *page,
+		size_t size)
+{
+	int ret = sg_alloc_table(sgt, 1, GFP_KERNEL);
+
+	if (!ret)
+		sg_set_page(sgt->sgl, page, PAGE_ALIGN(size), 0);
+	return ret;
+}
+
+static int iommu_dma_get_sgtable(struct device *dev, struct sg_table *sgt,
+		void *cpu_addr, dma_addr_t dma_addr, size_t size,
+		unsigned long attrs)
+{
+	unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
+	struct vm_struct *area = find_vm_area(cpu_addr);
+
+	if (!is_vmalloc_addr(cpu_addr)) {
+		struct page *page = virt_to_page(cpu_addr);
+		return __iommu_dma_get_sgtable_page(sgt, page, size);
+	}
+
+	if (attrs & DMA_ATTR_FORCE_CONTIGUOUS) {
+		/*
+		 * DMA_ATTR_FORCE_CONTIGUOUS allocations are always remapped,
+		 * hence in the vmalloc space.
+		 */
+		struct page *page = vmalloc_to_page(cpu_addr);
+		return __iommu_dma_get_sgtable_page(sgt, page, size);
+	}
+
+	if (WARN_ON(!area || !area->pages))
+		return -ENXIO;
+
+	return sg_alloc_table_from_pages(sgt, area->pages, count, 0, size,
+					 GFP_KERNEL);
+}
+
+static const struct dma_map_ops iommu_dma_ops = {
+	.alloc			= iommu_dma_alloc,
+	.free			= iommu_dma_free,
+	.mmap			= iommu_dma_mmap,
+	.get_sgtable		= iommu_dma_get_sgtable,
+	.map_page		= iommu_dma_map_page,
+	.unmap_page		= iommu_dma_unmap_page,
+	.map_sg			= iommu_dma_map_sg,
+	.unmap_sg		= iommu_dma_unmap_sg,
+	.sync_single_for_cpu	= iommu_dma_sync_single_for_cpu,
+	.sync_single_for_device	= iommu_dma_sync_single_for_device,
+	.sync_sg_for_cpu	= iommu_dma_sync_sg_for_cpu,
+	.sync_sg_for_device	= iommu_dma_sync_sg_for_device,
+	.map_resource		= iommu_dma_map_resource,
+	.unmap_resource		= iommu_dma_unmap_resource,
+};
+
+/*
+ * The IOMMU core code allocates the default DMA domain, which the underlying
+ * IOMMU driver needs to support via the dma-iommu layer.
+ */
+void iommu_setup_dma_ops(struct device *dev, u64 dma_base, u64 size)
+{
+	struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
+
+	if (!domain)
+		goto out_err;
+
+	/*
+	 * The IOMMU core code allocates the default DMA domain, which the
+	 * underlying IOMMU driver needs to support via the dma-iommu layer.
+	 */
+	if (domain->type == IOMMU_DOMAIN_DMA) {
+		if (iommu_dma_init_domain(domain, dma_base, size, dev))
+			goto out_err;
+		dev->dma_ops = &iommu_dma_ops;
+	}
+
+	return;
+out_err:
+	 pr_warn("Failed to set up IOMMU for device %s; retaining platform DMA ops\n",
+		 dev_name(dev));
+}
+
 static struct iommu_dma_msi_page *iommu_dma_get_msi_page(struct device *dev,
 		phys_addr_t msi_addr, struct iommu_domain *domain)
 {
@@ -921,3 +1247,9 @@  void iommu_dma_map_msi_msg(int irq, struct msi_msg *msg)
 		msg->address_lo += lower_32_bits(msi_page->iova);
 	}
 }
+
+static int iommu_dma_init(void)
+{
+	return iova_cache_get();
+}
+arch_initcall(iommu_dma_init);
diff --git a/include/linux/dma-iommu.h b/include/linux/dma-iommu.h
index 3216447178a7..dadf4383f555 100644
--- a/include/linux/dma-iommu.h
+++ b/include/linux/dma-iommu.h
@@ -24,49 +24,13 @@ 
 #include <linux/iommu.h>
 #include <linux/msi.h>
 
-int iommu_dma_init(void);
-
 /* Domain management interface for IOMMU drivers */
 int iommu_get_dma_cookie(struct iommu_domain *domain);
 int iommu_get_msi_cookie(struct iommu_domain *domain, dma_addr_t base);
 void iommu_put_dma_cookie(struct iommu_domain *domain);
 
 /* Setup call for arch DMA mapping code */
-int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base,
-		u64 size, struct device *dev);
-
-/* General helpers for DMA-API <-> IOMMU-API interaction */
-int dma_info_to_prot(enum dma_data_direction dir, bool coherent,
-		     unsigned long attrs);
-
-/*
- * These implement the bulk of the relevant DMA mapping callbacks, but require
- * the arch code to take care of attributes and cache maintenance
- */
-struct page **iommu_dma_alloc(struct device *dev, size_t size, gfp_t gfp,
-		unsigned long attrs, int prot, dma_addr_t *handle);
-void iommu_dma_free(struct device *dev, struct page **pages, size_t size,
-		dma_addr_t *handle);
-
-int iommu_dma_mmap(struct page **pages, size_t size, struct vm_area_struct *vma);
-
-dma_addr_t iommu_dma_map_page(struct device *dev, struct page *page,
-		unsigned long offset, size_t size, int prot);
-int iommu_dma_map_sg(struct device *dev, struct scatterlist *sg,
-		int nents, int prot);
-
-/*
- * Arch code with no special attribute handling may use these
- * directly as DMA mapping callbacks for simplicity
- */
-void iommu_dma_unmap_page(struct device *dev, dma_addr_t handle, size_t size,
-		enum dma_data_direction dir, unsigned long attrs);
-void iommu_dma_unmap_sg(struct device *dev, struct scatterlist *sg, int nents,
-		enum dma_data_direction dir, unsigned long attrs);
-dma_addr_t iommu_dma_map_resource(struct device *dev, phys_addr_t phys,
-		size_t size, enum dma_data_direction dir, unsigned long attrs);
-void iommu_dma_unmap_resource(struct device *dev, dma_addr_t handle,
-		size_t size, enum dma_data_direction dir, unsigned long attrs);
+void iommu_setup_dma_ops(struct device *dev, u64 dma_base, u64 size);
 
 /* The DMA API isn't _quite_ the whole story, though... */
 void iommu_dma_map_msi_msg(int irq, struct msi_msg *msg);
@@ -75,12 +39,13 @@  void iommu_dma_get_resv_regions(struct device *dev, struct list_head *list);
 #else /* CONFIG_IOMMU_DMA */
 
 struct iommu_domain;
+struct iommu_ops;
 struct msi_msg;
 struct device;
 
-static inline int iommu_dma_init(void)
+static inline void iommu_setup_dma_ops(struct device *dev, u64 dma_base,
+		u64 size)
 {
-	return 0;
 }
 
 static inline int iommu_get_dma_cookie(struct iommu_domain *domain)