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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
883a3e52 DG |
2 | /* |
3 | * PPC64 Huge TLB Page Support for hash based MMUs (POWER4 and later) | |
4 | * | |
5 | * Copyright (C) 2003 David Gibson, IBM Corporation. | |
6 | * | |
7 | * Based on the IA-32 version: | |
8 | * Copyright (C) 2002, Rohit Seth <rohit.seth@intel.com> | |
9 | */ | |
10 | ||
11 | #include <linux/mm.h> | |
12 | #include <linux/hugetlb.h> | |
13 | #include <asm/pgtable.h> | |
14 | #include <asm/pgalloc.h> | |
15 | #include <asm/cacheflush.h> | |
16 | #include <asm/machdep.h> | |
17 | ||
b170bd3d LZ |
18 | extern long hpte_insert_repeating(unsigned long hash, unsigned long vpn, |
19 | unsigned long pa, unsigned long rlags, | |
20 | unsigned long vflags, int psize, int ssize); | |
21 | ||
883a3e52 | 22 | int __hash_page_huge(unsigned long ea, unsigned long access, unsigned long vsid, |
aefa5688 AK |
23 | pte_t *ptep, unsigned long trap, unsigned long flags, |
24 | int ssize, unsigned int shift, unsigned int mmu_psize) | |
883a3e52 | 25 | { |
5524a27d | 26 | unsigned long vpn; |
883a3e52 | 27 | unsigned long old_pte, new_pte; |
5524a27d | 28 | unsigned long rflags, pa, sz; |
883a3e52 | 29 | long slot; |
883a3e52 DG |
30 | |
31 | BUG_ON(shift != mmu_psize_defs[mmu_psize].shift); | |
32 | ||
33 | /* Search the Linux page table for a match with va */ | |
5524a27d | 34 | vpn = hpt_vpn(ea, vsid, ssize); |
883a3e52 | 35 | |
171aa2ca | 36 | /* At this point, we have a pte (old_pte) which can be used to build |
883a3e52 DG |
37 | * or update an HPTE. There are 2 cases: |
38 | * | |
39 | * 1. There is a valid (present) pte with no associated HPTE (this is | |
40 | * the most common case) | |
41 | * 2. There is a valid (present) pte with an associated HPTE. The | |
42 | * current values of the pp bits in the HPTE prevent access | |
43 | * because we are doing software DIRTY bit management and the | |
44 | * page is currently not DIRTY. | |
45 | */ | |
46 | ||
47 | ||
48 | do { | |
49 | old_pte = pte_val(*ptep); | |
171aa2ca | 50 | /* If PTE busy, retry the access */ |
945537df | 51 | if (unlikely(old_pte & H_PAGE_BUSY)) |
171aa2ca BH |
52 | return 0; |
53 | /* If PTE permissions don't match, take page fault */ | |
ac29c640 | 54 | if (unlikely(!check_pte_access(access, old_pte))) |
171aa2ca | 55 | return 1; |
ac29c640 | 56 | |
171aa2ca BH |
57 | /* Try to lock the PTE, add ACCESSED and DIRTY if it was |
58 | * a write access */ | |
945537df | 59 | new_pte = old_pte | H_PAGE_BUSY | _PAGE_ACCESSED; |
c7d54842 | 60 | if (access & _PAGE_WRITE) |
171aa2ca | 61 | new_pte |= _PAGE_DIRTY; |
3910a7f4 ME |
62 | } while(!pte_xchg(ptep, __pte(old_pte), __pte(new_pte))); |
63 | ||
c6a3c495 | 64 | rflags = htab_convert_pte_flags(new_pte); |
883a3e52 | 65 | |
883a3e52 DG |
66 | sz = ((1UL) << shift); |
67 | if (!cpu_has_feature(CPU_FTR_COHERENT_ICACHE)) | |
68 | /* No CPU has hugepages but lacks no execute, so we | |
69 | * don't need to worry about that case */ | |
0895ecda | 70 | rflags = hash_page_do_lazy_icache(rflags, __pte(old_pte), trap); |
883a3e52 DG |
71 | |
72 | /* Check if pte already has an hpte (case 2) */ | |
945537df | 73 | if (unlikely(old_pte & H_PAGE_HASHPTE)) { |
883a3e52 DG |
74 | /* There MIGHT be an HPTE for this pte */ |
75 | unsigned long hash, slot; | |
76 | ||
5524a27d | 77 | hash = hpt_hash(vpn, shift, ssize); |
945537df | 78 | if (old_pte & H_PAGE_F_SECOND) |
883a3e52 DG |
79 | hash = ~hash; |
80 | slot = (hash & htab_hash_mask) * HPTES_PER_GROUP; | |
945537df | 81 | slot += (old_pte & H_PAGE_F_GIX) >> H_PAGE_F_GIX_SHIFT; |
883a3e52 | 82 | |
7025776e BH |
83 | if (mmu_hash_ops.hpte_updatepp(slot, rflags, vpn, mmu_psize, |
84 | mmu_psize, ssize, flags) == -1) | |
883a3e52 DG |
85 | old_pte &= ~_PAGE_HPTEFLAGS; |
86 | } | |
87 | ||
945537df | 88 | if (likely(!(old_pte & H_PAGE_HASHPTE))) { |
5524a27d | 89 | unsigned long hash = hpt_hash(vpn, shift, ssize); |
883a3e52 DG |
90 | |
91 | pa = pte_pfn(__pte(old_pte)) << PAGE_SHIFT; | |
92 | ||
883a3e52 | 93 | /* clear HPTE slot informations in new PTE */ |
945537df | 94 | new_pte = (new_pte & ~_PAGE_HPTEFLAGS) | H_PAGE_HASHPTE; |
bf680d51 | 95 | |
b170bd3d LZ |
96 | slot = hpte_insert_repeating(hash, vpn, pa, rflags, 0, |
97 | mmu_psize, ssize); | |
883a3e52 | 98 | |
b1623e7e AB |
99 | /* |
100 | * Hypervisor failure. Restore old pte and return -1 | |
101 | * similar to __hash_page_* | |
102 | */ | |
103 | if (unlikely(slot == -2)) { | |
104 | *ptep = __pte(old_pte); | |
4b8692c0 | 105 | hash_failure_debug(ea, access, vsid, trap, ssize, |
d8139ebf | 106 | mmu_psize, mmu_psize, old_pte); |
171aa2ca | 107 | return -1; |
b1623e7e | 108 | } |
883a3e52 | 109 | |
945537df AK |
110 | new_pte |= (slot << H_PAGE_F_GIX_SHIFT) & |
111 | (H_PAGE_F_SECOND | H_PAGE_F_GIX); | |
883a3e52 DG |
112 | } |
113 | ||
114 | /* | |
115 | * No need to use ldarx/stdcx here | |
116 | */ | |
945537df | 117 | *ptep = __pte(new_pte & ~H_PAGE_BUSY); |
171aa2ca | 118 | return 0; |
883a3e52 | 119 | } |