pte-hash32.h 1.9 KB

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  1. #ifndef _ASM_POWERPC_PTE_HASH32_H
  2. #define _ASM_POWERPC_PTE_HASH32_H
  3. #ifdef __KERNEL__
  4. /*
  5. * The "classic" 32-bit implementation of the PowerPC MMU uses a hash
  6. * table containing PTEs, together with a set of 16 segment registers,
  7. * to define the virtual to physical address mapping.
  8. *
  9. * We use the hash table as an extended TLB, i.e. a cache of currently
  10. * active mappings. We maintain a two-level page table tree, much
  11. * like that used by the i386, for the sake of the Linux memory
  12. * management code. Low-level assembler code in hash_low_32.S
  13. * (procedure hash_page) is responsible for extracting ptes from the
  14. * tree and putting them into the hash table when necessary, and
  15. * updating the accessed and modified bits in the page table tree.
  16. */
  17. #define _PAGE_PRESENT 0x001 /* software: pte contains a translation */
  18. #define _PAGE_HASHPTE 0x002 /* hash_page has made an HPTE for this pte */
  19. #define _PAGE_FILE 0x004 /* when !present: nonlinear file mapping */
  20. #define _PAGE_USER 0x004 /* usermode access allowed */
  21. #define _PAGE_GUARDED 0x008 /* G: prohibit speculative access */
  22. #define _PAGE_COHERENT 0x010 /* M: enforce memory coherence (SMP systems) */
  23. #define _PAGE_NO_CACHE 0x020 /* I: cache inhibit */
  24. #define _PAGE_WRITETHRU 0x040 /* W: cache write-through */
  25. #define _PAGE_DIRTY 0x080 /* C: page changed */
  26. #define _PAGE_ACCESSED 0x100 /* R: page referenced */
  27. #define _PAGE_RW 0x400 /* software: user write access allowed */
  28. #define _PAGE_SPECIAL 0x800 /* software: Special page */
  29. #ifdef CONFIG_PTE_64BIT
  30. /* We never clear the high word of the pte */
  31. #define _PTE_NONE_MASK (0xffffffff00000000ULL | _PAGE_HASHPTE)
  32. #else
  33. #define _PTE_NONE_MASK _PAGE_HASHPTE
  34. #endif
  35. #define _PMD_PRESENT 0
  36. #define _PMD_PRESENT_MASK (PAGE_MASK)
  37. #define _PMD_BAD (~PAGE_MASK)
  38. /* Hash table based platforms need atomic updates of the linux PTE */
  39. #define PTE_ATOMIC_UPDATES 1
  40. #endif /* __KERNEL__ */
  41. #endif /* _ASM_POWERPC_PTE_HASH32_H */