diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2017-04-09 09:05:25 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-04-09 09:05:25 -0700 |
commit | 462e9a355e7488fde3712c3b2585fc2f2a2c263d (patch) | |
tree | 2f1cdf7e4b72281f9fba51b6d1515c2b46f8434b /arch/arm/mm/dma-mapping.c | |
parent | 5b50be743f495b000891d430ecba7372cc59bb64 (diff) | |
parent | 3872fe83a2fbb7366daa93ca533a22138e2d483e (diff) |
Merge branch 'fixes' of git://git.armlinux.org.uk/~rmk/linux-arm
Pull ARM fixes from Russell King:
"A number of ARM fixes:
- prevent oopses caused by dma_get_sgtable() and declared DMA
coherent memory
- fix boot failure on nommu caused by ID_PFR1 access
- a number of kprobes fixes from Jon Medhurst and Masami Hiramatsu"
* 'fixes' of git://git.armlinux.org.uk/~rmk/linux-arm:
ARM: 8665/1: nommu: access ID_PFR1 only if CPUID scheme
ARM: dma-mapping: disallow dma_get_sgtable() for non-kernel managed memory
arm: kprobes: Align stack to 8-bytes in test code
arm: kprobes: Fix the return address of multiple kretprobes
arm: kprobes: Skip single-stepping in recursing path if possible
arm: kprobes: Allow to handle reentered kprobe on single-stepping
Diffstat (limited to 'arch/arm/mm/dma-mapping.c')
-rw-r--r-- | arch/arm/mm/dma-mapping.c | 20 |
1 files changed, 19 insertions, 1 deletions
diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c index 63eabb06f9f1..475811f5383a 100644 --- a/arch/arm/mm/dma-mapping.c +++ b/arch/arm/mm/dma-mapping.c @@ -935,13 +935,31 @@ static void arm_coherent_dma_free(struct device *dev, size_t size, void *cpu_add __arm_dma_free(dev, size, cpu_addr, handle, attrs, true); } +/* + * The whole dma_get_sgtable() idea is fundamentally unsafe - it seems + * that the intention is to allow exporting memory allocated via the + * coherent DMA APIs through the dma_buf API, which only accepts a + * scattertable. This presents a couple of problems: + * 1. Not all memory allocated via the coherent DMA APIs is backed by + * a struct page + * 2. Passing coherent DMA memory into the streaming APIs is not allowed + * as we will try to flush the memory through a different alias to that + * actually being used (and the flushes are redundant.) + */ int arm_dma_get_sgtable(struct device *dev, struct sg_table *sgt, void *cpu_addr, dma_addr_t handle, size_t size, unsigned long attrs) { - struct page *page = pfn_to_page(dma_to_pfn(dev, handle)); + unsigned long pfn = dma_to_pfn(dev, handle); + struct page *page; int ret; + /* If the PFN is not valid, we do not have a struct page */ + if (!pfn_valid(pfn)) + return -ENXIO; + + page = pfn_to_page(pfn); + ret = sg_alloc_table(sgt, 1, GFP_KERNEL); if (unlikely(ret)) return ret; |