LXR linux/arch/sparc/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 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/fixmap.h>
  25#include <asm/vaddrs.h>
  26#include <asm/kmap_types.h>
  27#include <asm/pgtable.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
  36extern void kmap_init(void) __init;
  37
  38/*
  39 * Right now we initialize only a single pte table. It can be extended
  40 * easily, subsequent pte tables have to be allocated in one physical
  41 * chunk of RAM.  Currently the simplest way to do this is to align the
  42 * pkmap region on a pagetable boundary (4MB).
  43 */
  44#define LAST_PKMAP 1024
  45#define PKMAP_SIZE (LAST_PKMAP << PAGE_SHIFT)
  46#define PKMAP_BASE PMD_ALIGN(SRMMU_NOCACHE_VADDR + (SRMMU_MAX_NOCACHE_PAGES << PAGE_SHIFT))
  47
  48#define LAST_PKMAP_MASK (LAST_PKMAP - 1)
  49#define PKMAP_NR(virt)  ((virt - PKMAP_BASE) >> PAGE_SHIFT)
  50#define PKMAP_ADDR(nr)  (PKMAP_BASE + ((nr) << PAGE_SHIFT))
  51
  52#define PKMAP_END (PKMAP_ADDR(LAST_PKMAP))
  53
  54extern void *kmap_high(struct page *page);
  55extern void kunmap_high(struct page *page);
  56
  57static inline void *kmap(struct page *page)
  58{
  59        BUG_ON(in_interrupt());
  60        if (!PageHighMem(page))
  61                return page_address(page);
  62        return kmap_high(page);
  63}
  64
  65static inline void kunmap(struct page *page)
  66{
  67        BUG_ON(in_interrupt());
  68        if (!PageHighMem(page))
  69                return;
  70        kunmap_high(page);
  71}
  72
  73extern void *__kmap_atomic(struct page *page);
  74extern void __kunmap_atomic(void *kvaddr);
  75extern struct page *kmap_atomic_to_page(void *vaddr);
  76
  77#define flush_cache_kmaps()     flush_cache_all()
  78
  79#endif /* __KERNEL__ */
  80
  81#endif /* _ASM_HIGHMEM_H */
  82