highmem.h 2.1 KB

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  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. #ifndef _ASM_HIGHMEM_H
  18. #define _ASM_HIGHMEM_H
  19. #ifdef __KERNEL__
  20. #include <linux/interrupt.h>
  21. #include <asm/fixmap.h>
  22. #include <asm/vaddrs.h>
  23. #include <asm/kmap_types.h>
  24. #include <asm/pgtable.h>
  25. /* declarations for highmem.c */
  26. extern unsigned long highstart_pfn, highend_pfn;
  27. extern pte_t *kmap_pte;
  28. extern pgprot_t kmap_prot;
  29. extern pte_t *pkmap_page_table;
  30. extern void kmap_init(void) __init;
  31. /*
  32. * Right now we initialize only a single pte table. It can be extended
  33. * easily, subsequent pte tables have to be allocated in one physical
  34. * chunk of RAM. Currently the simplest way to do this is to align the
  35. * pkmap region on a pagetable boundary (4MB).
  36. */
  37. #define LAST_PKMAP 1024
  38. #define PKMAP_SIZE (LAST_PKMAP << PAGE_SHIFT)
  39. #define PKMAP_BASE PMD_ALIGN(SRMMU_NOCACHE_VADDR + (SRMMU_MAX_NOCACHE_PAGES << PAGE_SHIFT))
  40. #define LAST_PKMAP_MASK (LAST_PKMAP - 1)
  41. #define PKMAP_NR(virt) ((virt - PKMAP_BASE) >> PAGE_SHIFT)
  42. #define PKMAP_ADDR(nr) (PKMAP_BASE + ((nr) << PAGE_SHIFT))
  43. #define PKMAP_END (PKMAP_ADDR(LAST_PKMAP))
  44. extern void *kmap_high(struct page *page);
  45. extern void kunmap_high(struct page *page);
  46. static inline void *kmap(struct page *page)
  47. {
  48. BUG_ON(in_interrupt());
  49. if (!PageHighMem(page))
  50. return page_address(page);
  51. return kmap_high(page);
  52. }
  53. static inline void kunmap(struct page *page)
  54. {
  55. BUG_ON(in_interrupt());
  56. if (!PageHighMem(page))
  57. return;
  58. kunmap_high(page);
  59. }
  60. extern void *kmap_atomic(struct page *page);
  61. extern void __kunmap_atomic(void *kvaddr);
  62. extern struct page *kmap_atomic_to_page(void *vaddr);
  63. #define flush_cache_kmaps() flush_cache_all()
  64. #endif /* __KERNEL__ */
  65. #endif /* _ASM_HIGHMEM_H */