diff options
Diffstat (limited to 'arch/arm/include/asm/highmem.h')
| -rw-r--r-- | arch/arm/include/asm/highmem.h | 39 |
1 files changed, 36 insertions, 3 deletions
diff --git a/arch/arm/include/asm/highmem.h b/arch/arm/include/asm/highmem.h index 7080e2c8fa6..535579511ed 100644 --- a/arch/arm/include/asm/highmem.h +++ b/arch/arm/include/asm/highmem.h @@ -18,12 +18,45 @@ } while (0) extern pte_t *pkmap_page_table; +extern pte_t *fixmap_page_table; +extern void *kmap_high(struct page *page); +extern void kunmap_high(struct page *page); + +/* + * The reason for kmap_high_get() is to ensure that the currently kmap'd + * page usage count does not decrease to zero while we're using its + * existing virtual mapping in an atomic context. With a VIVT cache this + * is essential to do, but with a VIPT cache this is only an optimization + * so not to pay the price of establishing a second mapping if an existing + * one can be used. However, on platforms without hardware TLB maintenance + * broadcast, we simply cannot use ARCH_NEEDS_KMAP_HIGH_GET at all since + * the locking involved must also disable IRQs which is incompatible with + * the IPI mechanism used by global TLB operations. + */ #define ARCH_NEEDS_KMAP_HIGH_GET +#if defined(CONFIG_SMP) && defined(CONFIG_CPU_TLB_V6) +#undef ARCH_NEEDS_KMAP_HIGH_GET +#if defined(CONFIG_HIGHMEM) && defined(CONFIG_CPU_CACHE_VIVT) +#error "The sum of features in your kernel config cannot be supported together" +#endif +#endif -extern void *kmap_high(struct page *page); +/* + * Needed to be able to broadcast the TLB invalidation for kmap. + */ +#ifdef CONFIG_ARM_ERRATA_798181 +#undef ARCH_NEEDS_KMAP_HIGH_GET +#endif + +#ifdef ARCH_NEEDS_KMAP_HIGH_GET extern void *kmap_high_get(struct page *page); -extern void kunmap_high(struct page *page); +#else +static inline void *kmap_high_get(struct page *page) +{ + return NULL; +} +#endif /* * The following functions are already defined by <linux/highmem.h> @@ -32,7 +65,7 @@ extern void kunmap_high(struct page *page); #ifdef CONFIG_HIGHMEM extern void *kmap(struct page *page); extern void kunmap(struct page *page); -extern void *__kmap_atomic(struct page *page); +extern void *kmap_atomic(struct page *page); extern void __kunmap_atomic(void *kvaddr); extern void *kmap_atomic_pfn(unsigned long pfn); extern struct page *kmap_atomic_to_page(const void *ptr); |