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883a3e52 DG |
1 | /* |
2 | * PPC64 Huge TLB Page Support for hash based MMUs (POWER4 and later) | |
3 | * | |
4 | * Copyright (C) 2003 David Gibson, IBM Corporation. | |
5 | * | |
6 | * Based on the IA-32 version: | |
7 | * Copyright (C) 2002, Rohit Seth <rohit.seth@intel.com> | |
8 | */ | |
9 | ||
10 | #include <linux/mm.h> | |
11 | #include <linux/hugetlb.h> | |
12 | #include <asm/pgtable.h> | |
13 | #include <asm/pgalloc.h> | |
14 | #include <asm/cacheflush.h> | |
15 | #include <asm/machdep.h> | |
16 | ||
b170bd3d LZ |
17 | extern long hpte_insert_repeating(unsigned long hash, unsigned long vpn, |
18 | unsigned long pa, unsigned long rlags, | |
19 | unsigned long vflags, int psize, int ssize); | |
20 | ||
883a3e52 | 21 | int __hash_page_huge(unsigned long ea, unsigned long access, unsigned long vsid, |
aefa5688 AK |
22 | pte_t *ptep, unsigned long trap, unsigned long flags, |
23 | int ssize, unsigned int shift, unsigned int mmu_psize) | |
883a3e52 | 24 | { |
5524a27d | 25 | unsigned long vpn; |
883a3e52 | 26 | unsigned long old_pte, new_pte; |
5524a27d | 27 | unsigned long rflags, pa, sz; |
883a3e52 | 28 | long slot; |
883a3e52 DG |
29 | |
30 | BUG_ON(shift != mmu_psize_defs[mmu_psize].shift); | |
31 | ||
32 | /* Search the Linux page table for a match with va */ | |
5524a27d | 33 | vpn = hpt_vpn(ea, vsid, ssize); |
883a3e52 | 34 | |
171aa2ca | 35 | /* At this point, we have a pte (old_pte) which can be used to build |
883a3e52 DG |
36 | * or update an HPTE. There are 2 cases: |
37 | * | |
38 | * 1. There is a valid (present) pte with no associated HPTE (this is | |
39 | * the most common case) | |
40 | * 2. There is a valid (present) pte with an associated HPTE. The | |
41 | * current values of the pp bits in the HPTE prevent access | |
42 | * because we are doing software DIRTY bit management and the | |
43 | * page is currently not DIRTY. | |
44 | */ | |
45 | ||
46 | ||
47 | do { | |
48 | old_pte = pte_val(*ptep); | |
171aa2ca | 49 | /* If PTE busy, retry the access */ |
945537df | 50 | if (unlikely(old_pte & H_PAGE_BUSY)) |
171aa2ca BH |
51 | return 0; |
52 | /* If PTE permissions don't match, take page fault */ | |
ac29c640 | 53 | if (unlikely(!check_pte_access(access, old_pte))) |
171aa2ca | 54 | return 1; |
ac29c640 | 55 | |
171aa2ca BH |
56 | /* Try to lock the PTE, add ACCESSED and DIRTY if it was |
57 | * a write access */ | |
945537df | 58 | new_pte = old_pte | H_PAGE_BUSY | _PAGE_ACCESSED; |
c7d54842 | 59 | if (access & _PAGE_WRITE) |
171aa2ca | 60 | new_pte |= _PAGE_DIRTY; |
3910a7f4 ME |
61 | } while(!pte_xchg(ptep, __pte(old_pte), __pte(new_pte))); |
62 | ||
c6a3c495 | 63 | rflags = htab_convert_pte_flags(new_pte); |
883a3e52 | 64 | |
883a3e52 DG |
65 | sz = ((1UL) << shift); |
66 | if (!cpu_has_feature(CPU_FTR_COHERENT_ICACHE)) | |
67 | /* No CPU has hugepages but lacks no execute, so we | |
68 | * don't need to worry about that case */ | |
0895ecda | 69 | rflags = hash_page_do_lazy_icache(rflags, __pte(old_pte), trap); |
883a3e52 DG |
70 | |
71 | /* Check if pte already has an hpte (case 2) */ | |
945537df | 72 | if (unlikely(old_pte & H_PAGE_HASHPTE)) { |
883a3e52 DG |
73 | /* There MIGHT be an HPTE for this pte */ |
74 | unsigned long hash, slot; | |
75 | ||
5524a27d | 76 | hash = hpt_hash(vpn, shift, ssize); |
945537df | 77 | if (old_pte & H_PAGE_F_SECOND) |
883a3e52 DG |
78 | hash = ~hash; |
79 | slot = (hash & htab_hash_mask) * HPTES_PER_GROUP; | |
945537df | 80 | slot += (old_pte & H_PAGE_F_GIX) >> H_PAGE_F_GIX_SHIFT; |
883a3e52 | 81 | |
5524a27d | 82 | if (ppc_md.hpte_updatepp(slot, rflags, vpn, mmu_psize, |
aefa5688 | 83 | mmu_psize, ssize, flags) == -1) |
883a3e52 DG |
84 | old_pte &= ~_PAGE_HPTEFLAGS; |
85 | } | |
86 | ||
945537df | 87 | if (likely(!(old_pte & H_PAGE_HASHPTE))) { |
5524a27d | 88 | unsigned long hash = hpt_hash(vpn, shift, ssize); |
883a3e52 DG |
89 | |
90 | pa = pte_pfn(__pte(old_pte)) << PAGE_SHIFT; | |
91 | ||
883a3e52 | 92 | /* clear HPTE slot informations in new PTE */ |
945537df | 93 | new_pte = (new_pte & ~_PAGE_HPTEFLAGS) | H_PAGE_HASHPTE; |
bf680d51 | 94 | |
b170bd3d LZ |
95 | slot = hpte_insert_repeating(hash, vpn, pa, rflags, 0, |
96 | mmu_psize, ssize); | |
883a3e52 | 97 | |
b1623e7e AB |
98 | /* |
99 | * Hypervisor failure. Restore old pte and return -1 | |
100 | * similar to __hash_page_* | |
101 | */ | |
102 | if (unlikely(slot == -2)) { | |
103 | *ptep = __pte(old_pte); | |
4b8692c0 | 104 | hash_failure_debug(ea, access, vsid, trap, ssize, |
d8139ebf | 105 | mmu_psize, mmu_psize, old_pte); |
171aa2ca | 106 | return -1; |
b1623e7e | 107 | } |
883a3e52 | 108 | |
945537df AK |
109 | new_pte |= (slot << H_PAGE_F_GIX_SHIFT) & |
110 | (H_PAGE_F_SECOND | H_PAGE_F_GIX); | |
883a3e52 DG |
111 | } |
112 | ||
113 | /* | |
114 | * No need to use ldarx/stdcx here | |
115 | */ | |
945537df | 116 | *ptep = __pte(new_pte & ~H_PAGE_BUSY); |
171aa2ca | 117 | return 0; |
883a3e52 | 118 | } |
26a344ae AK |
119 | |
120 | #if defined(CONFIG_PPC_64K_PAGES) && defined(CONFIG_DEBUG_VM) | |
121 | /* | |
122 | * This enables us to catch the wrong page directory format | |
123 | * Moved here so that we can use WARN() in the call. | |
124 | */ | |
125 | int hugepd_ok(hugepd_t hpd) | |
126 | { | |
127 | bool is_hugepd; | |
128 | ||
129 | /* | |
130 | * We should not find this format in page directory, warn otherwise. | |
131 | */ | |
132 | is_hugepd = (((hpd.pd & 0x3) == 0x0) && ((hpd.pd & HUGEPD_SHIFT_MASK) != 0)); | |
133 | WARN(is_hugepd, "Found wrong page directory format\n"); | |
134 | return 0; | |
135 | } | |
136 | #endif |