1 /* 2 * highmem.h: virtual kernel memory mappings for high memory 3 * 4 * Used in CONFIG_HIGHMEM systems for memory pages which 5 * are not addressable by direct kernel virtual addresses. 6 * 7 * Copyright (C) 1999 Gerhard Wichert, Siemens AG 8 * Gerhard.Wichert@pdb.siemens.de 9 * 10 * 11 * Redesigned the x86 32-bit VM architecture to deal with 12 * up to 16 Terabyte physical memory. With current x86 CPUs 13 * we now support up to 64 Gigabytes physical RAM. 14 * 15 * Copyright (C) 1999 Ingo Molnar <mingo@redhat.com> 16 */ 17 #ifndef _ASM_HIGHMEM_H 18 #define _ASM_HIGHMEM_H 19 20 #ifdef __KERNEL__ 21 22 #include <linux/init.h> 23 #include <linux/interrupt.h> 24 #include <linux/uaccess.h> 25 #include <asm/kmap_types.h> 26 27 /* undef for production */ 28 #define HIGHMEM_DEBUG 1 29 30 /* declarations for highmem.c */ 31 extern unsigned long highstart_pfn, highend_pfn; 32 33 extern pte_t *kmap_pte; 34 extern pgprot_t kmap_prot; 35 extern pte_t *pkmap_page_table; 36 37 /* 38 * Right now we initialize only a single pte table. It can be extended 39 * easily, subsequent pte tables have to be allocated in one physical 40 * chunk of RAM. 41 */ 42 #define LAST_PKMAP 1024 43 #define LAST_PKMAP_MASK (LAST_PKMAP-1) 44 #define PKMAP_NR(virt) ((virt-PKMAP_BASE) >> PAGE_SHIFT) 45 #define PKMAP_ADDR(nr) (PKMAP_BASE + ((nr) << PAGE_SHIFT)) 46 47 extern void * kmap_high(struct page *page); 48 extern void kunmap_high(struct page *page); 49 50 extern void *__kmap(struct page *page); 51 extern void __kunmap(struct page *page); 52 extern void *__kmap_atomic(struct page *page, enum km_type type); 53 extern void __kunmap_atomic(void *kvaddr, enum km_type type); 54 extern void *kmap_atomic_pfn(unsigned long pfn, enum km_type type); 55 extern struct page *__kmap_atomic_to_page(void *ptr); 56 57 #define kmap __kmap 58 #define kunmap __kunmap 59 #define kmap_atomic __kmap_atomic 60 #define kunmap_atomic __kunmap_atomic 61 #define kmap_atomic_to_page __kmap_atomic_to_page 62 63 #define flush_cache_kmaps() flush_cache_all() 64 65 #endif /* __KERNEL__ */ 66 67 #endif /* _ASM_HIGHMEM_H */ 68