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 18#ifndef _ASM_HIGHMEM_H 19#define _ASM_HIGHMEM_H 20 21#ifdef __KERNEL__ 22 23#include <linux/interrupt.h> 24#include <linux/threads.h> 25#include <asm/kmap_types.h> 26#include <asm/tlbflush.h> 27#include <asm/paravirt.h> 28 29/* declarations for highmem.c */ 30extern unsigned long highstart_pfn, highend_pfn; 31 32extern pte_t *kmap_pte; 33extern pgprot_t kmap_prot; 34extern 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#ifdef CONFIG_X86_PAE 42#define LAST_PKMAP 512 43#else 44#define LAST_PKMAP 1024 45#endif 46/* 47 * Ordering is: 48 * 49 * FIXADDR_TOP 50 * fixed_addresses 51 * FIXADDR_START 52 * temp fixed addresses 53 * FIXADDR_BOOT_START 54 * Persistent kmap area 55 * PKMAP_BASE 56 * VMALLOC_END 57 * Vmalloc area 58 * VMALLOC_START 59 * high_memory 60 */ 61#define PKMAP_BASE ( (FIXADDR_BOOT_START - PAGE_SIZE*(LAST_PKMAP + 1)) & PMD_MASK ) 62#define LAST_PKMAP_MASK (LAST_PKMAP-1) 63#define PKMAP_NR(virt) ((virt-PKMAP_BASE) >> PAGE_SHIFT) 64#define PKMAP_ADDR(nr) (PKMAP_BASE + ((nr) << PAGE_SHIFT)) 65 66extern void * FASTCALL(kmap_high(struct page *page)); 67extern void FASTCALL(kunmap_high(struct page *page)); 68 69void *kmap(struct page *page); 70void kunmap(struct page *page); 71void *kmap_atomic_prot(struct page *page, enum km_type type, pgprot_t prot); 72void *kmap_atomic(struct page *page, enum km_type type); 73void kunmap_atomic(void *kvaddr, enum km_type type); 74void *kmap_atomic_pfn(unsigned long pfn, enum km_type type); 75struct page *kmap_atomic_to_page(void *ptr); 76 77#ifndef CONFIG_PARAVIRT 78#define kmap_atomic_pte(page, type) kmap_atomic(page, type) 79#endif 80 81#define flush_cache_kmaps() do { } while (0) 82 83#endif /* __KERNEL__ */ 84 85#endif /* _ASM_HIGHMEM_H */ 86