1#ifndef _ASM_HIGHMEM_H 2#define _ASM_HIGHMEM_H 3 4#include <asm/kmap_types.h> 5 6#define PKMAP_BASE (PAGE_OFFSET - PMD_SIZE) 7#define LAST_PKMAP PTRS_PER_PTE 8#define LAST_PKMAP_MASK (LAST_PKMAP - 1) 9#define PKMAP_NR(virt) (((virt) - PKMAP_BASE) >> PAGE_SHIFT) 10#define PKMAP_ADDR(nr) (PKMAP_BASE + ((nr) << PAGE_SHIFT)) 11 12#define kmap_prot PAGE_KERNEL 13 14#define flush_cache_kmaps() \ 15 do { \ 16 if (cache_is_vivt()) \ 17 flush_cache_all(); \ 18 } while (0) 19 20extern pte_t *pkmap_page_table; 21extern pte_t *fixmap_page_table; 22 23extern void *kmap_high(struct page *page); 24extern void kunmap_high(struct page *page); 25 26/* 27 * The reason for kmap_high_get() is to ensure that the currently kmap'd 28 * page usage count does not decrease to zero while we're using its 29 * existing virtual mapping in an atomic context. With a VIVT cache this 30 * is essential to do, but with a VIPT cache this is only an optimization 31 * so not to pay the price of establishing a second mapping if an existing 32 * one can be used. However, on platforms without hardware TLB maintenance 33 * broadcast, we simply cannot use ARCH_NEEDS_KMAP_HIGH_GET at all since 34 * the locking involved must also disable IRQs which is incompatible with 35 * the IPI mechanism used by global TLB operations. 36 */ 37#define ARCH_NEEDS_KMAP_HIGH_GET 38#if defined(CONFIG_SMP) && defined(CONFIG_CPU_TLB_V6) 39#undef ARCH_NEEDS_KMAP_HIGH_GET 40#if defined(CONFIG_HIGHMEM) && defined(CONFIG_CPU_CACHE_VIVT) 41#error "The sum of features in your kernel config cannot be supported together" 42#endif 43#endif 44 45/* 46 * Needed to be able to broadcast the TLB invalidation for kmap. 47 */ 48#ifdef CONFIG_ARM_ERRATA_798181 49#undef ARCH_NEEDS_KMAP_HIGH_GET 50#endif 51 52#ifdef ARCH_NEEDS_KMAP_HIGH_GET 53extern void *kmap_high_get(struct page *page); 54#else 55static inline void *kmap_high_get(struct page *page) 56{ 57 return NULL; 58} 59#endif 60 61/* 62 * The following functions are already defined by <linux/highmem.h> 63 * when CONFIG_HIGHMEM is not set. 64 */ 65#ifdef CONFIG_HIGHMEM 66extern void *kmap(struct page *page); 67extern void kunmap(struct page *page); 68extern void *kmap_atomic(struct page *page); 69extern void __kunmap_atomic(void *kvaddr); 70extern void *kmap_atomic_pfn(unsigned long pfn); 71extern struct page *kmap_atomic_to_page(const void *ptr); 72#endif 73 74#endif 75