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/bug.h> 23 #include <linux/interrupt.h> 24 #include <linux/uaccess.h> 25 #include <asm/cpu-features.h> 26 #include <asm/kmap_types.h> 27 28 /* undef for production */ 29 #define HIGHMEM_DEBUG 1 30 31 /* declarations for highmem.c */ 32 extern unsigned long highstart_pfn, highend_pfn; 33 34 extern pte_t *pkmap_page_table; 35 36 /* 37 * Right now we initialize only a single pte table. It can be extended 38 * easily, subsequent pte tables have to be allocated in one physical 39 * chunk of RAM. 40 */ 41 #define LAST_PKMAP 1024 42 #define LAST_PKMAP_MASK (LAST_PKMAP-1) 43 #define PKMAP_NR(virt) ((virt-PKMAP_BASE) >> PAGE_SHIFT) 44 #define PKMAP_ADDR(nr) (PKMAP_BASE + ((nr) << PAGE_SHIFT)) 45 46 extern void * kmap_high(struct page *page); 47 extern void kunmap_high(struct page *page); 48 49 extern void *kmap(struct page *page); 50 extern void kunmap(struct page *page); 51 extern void *kmap_atomic(struct page *page); 52 extern void __kunmap_atomic(void *kvaddr); 53 extern void *kmap_atomic_pfn(unsigned long pfn); 54 55 #define flush_cache_kmaps() BUG_ON(cpu_has_dc_aliases) 56 57 extern void kmap_init(void); 58 59 #define kmap_prot PAGE_KERNEL 60 61 #endif /* __KERNEL__ */ 62 63 #endif /* _ASM_HIGHMEM_H */ 64