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