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dma-mapping: fix page attributes for dma_mmap_*

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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: 64ccc9c033 ("common: dma-mapping: add support for generic dma_mmap_* calls")
Reported-by: Shawn Anastasio <shawn@anastas.io>
Reported-by: Gavin Li <git@thegavinli.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Catalin Marinas <catalin.marinas@arm.com> # arm64
This commit is contained in:
Christoph Hellwig 2019-07-26 09:26:40 +02:00
parent d8ad55538a
commit 33dcb37cef
9 changed files with 34 additions and 35 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
arch/arm/mm/dma-mapping.c
View File

@ -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;
}
void *arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,

2
arch/arm64/mm/dma-mapping.c
View File

@ -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;
}
void arch_sync_dma_for_device(struct device *dev, phys_addr_t paddr,

1
arch/powerpc/Kconfig
View File

@ -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

3
arch/powerpc/kernel/Makefile
View File

@ -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

17
arch/powerpc/kernel/dma-common.c
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@ -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 <linux/mm.h>
#include <linux/dma-noncoherent.h>
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;
}

6
drivers/iommu/dma-iommu.c
View File

@ -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;

13
include/linux/dma-noncoherent.h
View File

@ -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,

19
kernel/dma/mapping.c
View File

@ -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;

2
kernel/dma/remap.c
View File

@ -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);