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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 */ | |
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29 | #define _PAGE_RW 0x400 /* software: user write access allowed */ |
30 | #define _PAGE_SPECIAL 0x800 /* software: Special page */ | |
31 | ||
32 | #ifdef CONFIG_PTE_64BIT | |
33 | /* We never clear the high word of the pte */ | |
34 | #define _PTE_NONE_MASK (0xffffffff00000000ULL | _PAGE_HASHPTE) | |
35 | #else | |
36 | #define _PTE_NONE_MASK _PAGE_HASHPTE | |
37 | #endif | |
38 | ||
39 | #define _PMD_PRESENT 0 | |
40 | #define _PMD_PRESENT_MASK (PAGE_MASK) | |
41 | #define _PMD_BAD (~PAGE_MASK) | |
42 | ||
43 | /* Hash table based platforms need atomic updates of the linux PTE */ | |
44 | #define PTE_ATOMIC_UPDATES 1 | |
45 | ||
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46 | #endif /* __KERNEL__ */ |
47 | #endif /* _ASM_POWERPC_PTE_HASH32_H */ |