diff options
Diffstat (limited to 'arch/arm/mm')
| -rw-r--r-- | arch/arm/mm/dma-mapping.c | 20 | ||||
| -rw-r--r-- | arch/arm/mm/nommu.c | 5 |
2 files changed, 23 insertions, 2 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; diff --git a/arch/arm/mm/nommu.c b/arch/arm/mm/nommu.c index 3b5c7aaf9c76..33a45bd96860 100644 --- a/arch/arm/mm/nommu.c +++ b/arch/arm/mm/nommu.c @@ -303,7 +303,10 @@ static inline void set_vbar(unsigned long val) */ static inline bool security_extensions_enabled(void) { - return !!cpuid_feature_extract(CPUID_EXT_PFR1, 4); + /* Check CPUID Identification Scheme before ID_PFR1 read */ + if ((read_cpuid_id() & 0x000f0000) == 0x000f0000) + return !!cpuid_feature_extract(CPUID_EXT_PFR1, 4); + return 0; } static unsigned long __init setup_vectors_base(void) |