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 */
  31 extern 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
  60 extern void *kmap_high(struct page *page);
  61 extern void kunmap_high(struct page *page);
  62
  63 void *kmap(struct page *page);
  64 void kunmap(struct page *page);
  65
  66 void *kmap_atomic_prot(struct page *page, pgprot_t prot);
  67 void *kmap_atomic(struct page *page);
  68 void __kunmap_atomic(void *kvaddr);
  69 void *kmap_atomic_pfn(unsigned long pfn);
  70 void *kmap_atomic_prot_pfn(unsigned long pfn, pgprot_t prot);
  71
  72 #define flush_cache_kmaps()     do { } while (0)
  73
  74 extern 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 */