blob: 4aad4132d0a87fa3e677ebe00b05d0d317fe7292 [file] [log] [blame]
#ifdef __KERNEL__
* The "classic" 32-bit implementation of the PowerPC MMU uses a hash
* table containing PTEs, together with a set of 16 segment registers,
* to define the virtual to physical address mapping.
* We use the hash table as an extended TLB, i.e. a cache of currently
* active mappings. We maintain a two-level page table tree, much
* like that used by the i386, for the sake of the Linux memory
* management code. Low-level assembler code in hash_low_32.S
* (procedure hash_page) is responsible for extracting ptes from the
* tree and putting them into the hash table when necessary, and
* updating the accessed and modified bits in the page table tree.
#define _PAGE_PRESENT 0x001 /* software: pte contains a translation */
#define _PAGE_HASHPTE 0x002 /* hash_page has made an HPTE for this pte */
#define _PAGE_FILE 0x004 /* when !present: nonlinear file mapping */
#define _PAGE_USER 0x004 /* usermode access allowed */
#define _PAGE_GUARDED 0x008 /* G: prohibit speculative access */
#define _PAGE_COHERENT 0x010 /* M: enforce memory coherence (SMP systems) */
#define _PAGE_NO_CACHE 0x020 /* I: cache inhibit */
#define _PAGE_WRITETHRU 0x040 /* W: cache write-through */
#define _PAGE_DIRTY 0x080 /* C: page changed */
#define _PAGE_ACCESSED 0x100 /* R: page referenced */
#define _PAGE_RW 0x400 /* software: user write access allowed */
#define _PAGE_SPECIAL 0x800 /* software: Special page */
/* We never clear the high word of the pte */
#define _PTE_NONE_MASK (0xffffffff00000000ULL | _PAGE_HASHPTE)
#define _PMD_PRESENT 0
#define _PMD_BAD (~PAGE_MASK)
/* Hash table based platforms need atomic updates of the linux PTE */
#endif /* __KERNEL__ */
#endif /* _ASM_POWERPC_PTE_HASH32_H */