| Benjamin Herrenschmidt | c605782 | 2009-03-10 17:53:29 +0000 | [diff] [blame^] | 1 | #ifndef _ASM_POWERPC_PTE_HASH32_H |
| 2 | #define _ASM_POWERPC_PTE_HASH32_H |
| 3 | #ifdef __KERNEL__ |
| 4 | |
| 5 | /* |
| 6 | * The "classic" 32-bit implementation of the PowerPC MMU uses a hash |
| 7 | * table containing PTEs, together with a set of 16 segment registers, |
| 8 | * to define the virtual to physical address mapping. |
| 9 | * |
| 10 | * We use the hash table as an extended TLB, i.e. a cache of currently |
| 11 | * active mappings. We maintain a two-level page table tree, much |
| 12 | * like that used by the i386, for the sake of the Linux memory |
| 13 | * management code. Low-level assembler code in hash_low_32.S |
| 14 | * (procedure hash_page) is responsible for extracting ptes from the |
| 15 | * tree and putting them into the hash table when necessary, and |
| 16 | * updating the accessed and modified bits in the page table tree. |
| 17 | */ |
| 18 | |
| 19 | #define _PAGE_PRESENT 0x001 /* software: pte contains a translation */ |
| 20 | #define _PAGE_HASHPTE 0x002 /* hash_page has made an HPTE for this pte */ |
| 21 | #define _PAGE_FILE 0x004 /* when !present: nonlinear file mapping */ |
| 22 | #define _PAGE_USER 0x004 /* usermode access allowed */ |
| 23 | #define _PAGE_GUARDED 0x008 /* G: prohibit speculative access */ |
| 24 | #define _PAGE_COHERENT 0x010 /* M: enforce memory coherence (SMP systems) */ |
| 25 | #define _PAGE_NO_CACHE 0x020 /* I: cache inhibit */ |
| 26 | #define _PAGE_WRITETHRU 0x040 /* W: cache write-through */ |
| 27 | #define _PAGE_DIRTY 0x080 /* C: page changed */ |
| 28 | #define _PAGE_ACCESSED 0x100 /* R: page referenced */ |
| 29 | #define _PAGE_EXEC 0x200 /* software: i-cache coherency required */ |
| 30 | #define _PAGE_RW 0x400 /* software: user write access allowed */ |
| 31 | #define _PAGE_SPECIAL 0x800 /* software: Special page */ |
| 32 | |
| 33 | #ifdef CONFIG_PTE_64BIT |
| 34 | /* We never clear the high word of the pte */ |
| 35 | #define _PTE_NONE_MASK (0xffffffff00000000ULL | _PAGE_HASHPTE) |
| 36 | #else |
| 37 | #define _PTE_NONE_MASK _PAGE_HASHPTE |
| 38 | #endif |
| 39 | |
| 40 | #define _PMD_PRESENT 0 |
| 41 | #define _PMD_PRESENT_MASK (PAGE_MASK) |
| 42 | #define _PMD_BAD (~PAGE_MASK) |
| 43 | |
| 44 | /* Hash table based platforms need atomic updates of the linux PTE */ |
| 45 | #define PTE_ATOMIC_UPDATES 1 |
| 46 | |
| 47 | |
| 48 | #endif /* __KERNEL__ */ |
| 49 | #endif /* _ASM_POWERPC_PTE_HASH32_H */ |