LXR linux-old/include/asm-sparc/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 Terrabyte 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 <asm/kmap_types.h>
  25
  26/* undef for production */
  27#define HIGHMEM_DEBUG 1
  28
  29/* in mm/highmem.c */
  30extern void *kmap_high(struct page *page, int nonblocking);
  31extern void kunmap_high(struct page *page);
  32
  33/* declarations for highmem.c */
  34extern unsigned long highstart_pfn, highend_pfn;
  35
  36extern pte_t *kmap_pte;
  37extern pgprot_t kmap_prot;
  38extern pte_t *pkmap_page_table;
  39
  40/* This gets set in {srmmu,sun4c}_paging_init() */
  41extern unsigned long fix_kmap_begin;
  42
  43/* Only used and set with srmmu? */
  44extern unsigned long pkmap_base;
  45
  46extern void kmap_init(void) __init;
  47
  48/*
  49 * Right now we initialize only a single pte table. It can be extended
  50 * easily, subsequent pte tables have to be allocated in one physical
  51 * chunk of RAM.
  52 */
  53#define LAST_PKMAP 1024
  54
  55#define LAST_PKMAP_MASK         (LAST_PKMAP - 1)
  56#define PKMAP_NR(virt)          ((virt - pkmap_base) >> PAGE_SHIFT)
  57#define PKMAP_ADDR(nr)          (pkmap_base + ((nr) << PAGE_SHIFT))
  58
  59/* in arch/sparc/mm/highmem.c */
  60void *kmap_atomic(struct page *page, enum km_type type);
  61void kunmap_atomic(void *kvaddr, enum km_type type);
  62
  63#define kmap(page) __kmap(page, 0)
  64#define kmap_nonblock(page) __kmap(page, 1)
  65
  66static inline void *__kmap(struct page *page, int nonblocking)
  67{
  68        if (in_interrupt())
  69                BUG();
  70        if (page < highmem_start_page)
  71                return page_address(page);
  72        return kmap_high(page, nonblocking);
  73}
  74
  75static inline void kunmap(struct page *page)
  76{
  77        if (in_interrupt())
  78                BUG();
  79        if (page < highmem_start_page)
  80                return;
  81        kunmap_high(page);
  82}
  83
  84#endif /* __KERNEL__ */
  85
  86#endif /* _ASM_HIGHMEM_H */
  87