From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001 From: André Fabian Silva Delgado Date: Wed, 5 Aug 2015 17:04:01 -0300 Subject: Initial import --- arch/arm/include/asm/highmem.h | 74 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 74 insertions(+) create mode 100644 arch/arm/include/asm/highmem.h (limited to 'arch/arm/include/asm/highmem.h') diff --git a/arch/arm/include/asm/highmem.h b/arch/arm/include/asm/highmem.h new file mode 100644 index 000000000..535579511 --- /dev/null +++ b/arch/arm/include/asm/highmem.h @@ -0,0 +1,74 @@ +#ifndef _ASM_HIGHMEM_H +#define _ASM_HIGHMEM_H + +#include + +#define PKMAP_BASE (PAGE_OFFSET - PMD_SIZE) +#define LAST_PKMAP PTRS_PER_PTE +#define LAST_PKMAP_MASK (LAST_PKMAP - 1) +#define PKMAP_NR(virt) (((virt) - PKMAP_BASE) >> PAGE_SHIFT) +#define PKMAP_ADDR(nr) (PKMAP_BASE + ((nr) << PAGE_SHIFT)) + +#define kmap_prot PAGE_KERNEL + +#define flush_cache_kmaps() \ + do { \ + if (cache_is_vivt()) \ + flush_cache_all(); \ + } 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 + +/* + * 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); +#else +static inline void *kmap_high_get(struct page *page) +{ + return NULL; +} +#endif + +/* + * The following functions are already defined by + * when CONFIG_HIGHMEM is not set. + */ +#ifdef CONFIG_HIGHMEM +extern void *kmap(struct page *page); +extern void kunmap(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); +#endif + +#endif -- cgit v1.2.3-54-g00ecf