highmem.h 1.8 KB

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  1. /* SPDX-License-Identifier: GPL-2.0 */
  2. /*
  3. * highmem.h: virtual kernel memory mappings for high memory
  4. *
  5. * Used in CONFIG_HIGHMEM systems for memory pages which
  6. * are not addressable by direct kernel virtual addresses.
  7. *
  8. * Copyright (C) 1999 Gerhard Wichert, Siemens AG
  9. * [email protected]
  10. *
  11. *
  12. * Redesigned the x86 32-bit VM architecture to deal with
  13. * up to 16 Terabyte physical memory. With current x86 CPUs
  14. * we now support up to 64 Gigabytes physical RAM.
  15. *
  16. * Copyright (C) 1999 Ingo Molnar <[email protected]>
  17. */
  18. #ifndef _ASM_HIGHMEM_H
  19. #define _ASM_HIGHMEM_H
  20. #ifdef __KERNEL__
  21. #include <linux/init.h>
  22. #include <linux/interrupt.h>
  23. #include <linux/uaccess.h>
  24. #include <asm/fixmap.h>
  25. extern pte_t *pkmap_page_table;
  26. /*
  27. * Right now we initialize only a single pte table. It can be extended
  28. * easily, subsequent pte tables have to be allocated in one physical
  29. * chunk of RAM.
  30. */
  31. /*
  32. * We use one full pte table with 4K pages. And with 16K/64K/256K pages pte
  33. * table covers enough memory (32MB/512MB/2GB resp.), so that both FIXMAP
  34. * and PKMAP can be placed in a single pte table. We use 512 pages for PKMAP
  35. * in case of 16K/64K/256K page sizes.
  36. */
  37. #define PKMAP_ORDER PTE_SHIFT
  38. #define LAST_PKMAP (1 << PKMAP_ORDER)
  39. #define PKMAP_BASE ((FIXADDR_START - PAGE_SIZE * (LAST_PKMAP + 1)) \
  40. & PMD_MASK)
  41. #define LAST_PKMAP_MASK (LAST_PKMAP - 1)
  42. #define PKMAP_NR(virt) ((virt - PKMAP_BASE) >> PAGE_SHIFT)
  43. #define PKMAP_ADDR(nr) (PKMAP_BASE + ((nr) << PAGE_SHIFT))
  44. #define flush_cache_kmaps() { flush_icache(); flush_dcache(); }
  45. #define arch_kmap_local_post_map(vaddr, pteval) \
  46. local_flush_tlb_page(NULL, vaddr);
  47. #define arch_kmap_local_post_unmap(vaddr) \
  48. local_flush_tlb_page(NULL, vaddr);
  49. #endif /* __KERNEL__ */
  50. #endif /* _ASM_HIGHMEM_H */