LXR linux/arch/x86/include/asm/highmem.h

   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_X86_HIGHMEM_H
  19#define _ASM_X86_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#include <asm/fixmap.h>
  29
  30/* declarations for highmem.c */
  31extern unsigned long highstart_pfn, highend_pfn;
  32
  33/*
  34 * Right now we initialize only a single pte table. It can be extended
  35 * easily, subsequent pte tables have to be allocated in one physical
  36 * chunk of RAM.
  37 */
  38/*
  39 * Ordering is:
  40 *
  41 * high memory on:                                    high_memory off:
  42 *    FIXADDR_TOP                                        FIXADDR_TOP
  43 *        fixed addresses                                    fixed addresses
  44 *    FIXADDR_START                                      FIXADDR_START
  45 *        temp fixed addresses/persistent kmap area      VMALLOC_END
  46 *    PKMAP_BASE                                             temp fixed addresses/vmalloc area
  47 *    VMALLOC_END                                        VMALLOC_START
  48 *        vmalloc area                                   high_memory
  49 *    VMALLOC_START
  50 *    high_memory
  51 *
  52 * The temp fixed area is only used during boot for early_ioremap(), and
  53 * it is unused when the ioremap() is functional. vmalloc/pkmap area become
  54 * available after early boot so the temp fixed area is available for re-use.
  55 */
  56#define LAST_PKMAP_MASK (LAST_PKMAP-1)
  57#define PKMAP_NR(virt)  ((virt-PKMAP_BASE) >> PAGE_SHIFT)
  58#define PKMAP_ADDR(nr)  (PKMAP_BASE + ((nr) << PAGE_SHIFT))
  59
  60extern void *kmap_high(struct page *page);
  61extern void kunmap_high(struct page *page);
  62
  63void *kmap(struct page *page);
  64void kunmap(struct page *page);
  65
  66void *kmap_atomic_prot(struct page *page, pgprot_t prot);
  67void *kmap_atomic(struct page *page);
  68void __kunmap_atomic(void *kvaddr);
  69void *kmap_atomic_pfn(unsigned long pfn);
  70void *kmap_atomic_prot_pfn(unsigned long pfn, pgprot_t prot);
  71
  72#define flush_cache_kmaps()     do { } while (0)
  73
  74extern void add_highpages_with_active_regions(int nid, unsigned long start_pfn,
  75                                        unsigned long end_pfn);
  76
  77#endif /* __KERNEL__ */
  78
  79#endif /* _ASM_X86_HIGHMEM_H */
  80