arch/mips/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 #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 */