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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 | { |
bf9a95f9 | 26 | real_pte_t rpte; |
5524a27d | 27 | unsigned long vpn; |
883a3e52 | 28 | unsigned long old_pte, new_pte; |
8132cf11 | 29 | unsigned long rflags, pa; |
ff31e105 | 30 | long slot, offset; |
883a3e52 DG |
31 | |
32 | BUG_ON(shift != mmu_psize_defs[mmu_psize].shift); | |
33 | ||
34 | /* Search the Linux page table for a match with va */ | |
5524a27d | 35 | vpn = hpt_vpn(ea, vsid, ssize); |
883a3e52 | 36 | |
171aa2ca | 37 | /* At this point, we have a pte (old_pte) which can be used to build |
883a3e52 DG |
38 | * or update an HPTE. There are 2 cases: |
39 | * | |
40 | * 1. There is a valid (present) pte with no associated HPTE (this is | |
41 | * the most common case) | |
42 | * 2. There is a valid (present) pte with an associated HPTE. The | |
43 | * current values of the pp bits in the HPTE prevent access | |
44 | * because we are doing software DIRTY bit management and the | |
45 | * page is currently not DIRTY. | |
46 | */ | |
47 | ||
48 | ||
49 | do { | |
50 | old_pte = pte_val(*ptep); | |
171aa2ca | 51 | /* If PTE busy, retry the access */ |
945537df | 52 | if (unlikely(old_pte & H_PAGE_BUSY)) |
171aa2ca BH |
53 | return 0; |
54 | /* If PTE permissions don't match, take page fault */ | |
ac29c640 | 55 | if (unlikely(!check_pte_access(access, old_pte))) |
171aa2ca | 56 | return 1; |
ac29c640 | 57 | |
171aa2ca BH |
58 | /* Try to lock the PTE, add ACCESSED and DIRTY if it was |
59 | * a write access */ | |
945537df | 60 | new_pte = old_pte | H_PAGE_BUSY | _PAGE_ACCESSED; |
c7d54842 | 61 | if (access & _PAGE_WRITE) |
171aa2ca | 62 | new_pte |= _PAGE_DIRTY; |
3910a7f4 ME |
63 | } while(!pte_xchg(ptep, __pte(old_pte), __pte(new_pte))); |
64 | ||
75646c48 AK |
65 | /* Make sure this is a hugetlb entry */ |
66 | if (old_pte & (H_PAGE_THP_HUGE | _PAGE_DEVMAP)) | |
67 | return 0; | |
68 | ||
c6a3c495 | 69 | rflags = htab_convert_pte_flags(new_pte); |
ff31e105 AK |
70 | if (unlikely(mmu_psize == MMU_PAGE_16G)) |
71 | offset = PTRS_PER_PUD; | |
72 | else | |
73 | offset = PTRS_PER_PMD; | |
74 | rpte = __real_pte(__pte(old_pte), ptep, offset); | |
883a3e52 | 75 | |
883a3e52 DG |
76 | if (!cpu_has_feature(CPU_FTR_COHERENT_ICACHE)) |
77 | /* No CPU has hugepages but lacks no execute, so we | |
78 | * don't need to worry about that case */ | |
0895ecda | 79 | rflags = hash_page_do_lazy_icache(rflags, __pte(old_pte), trap); |
883a3e52 DG |
80 | |
81 | /* Check if pte already has an hpte (case 2) */ | |
945537df | 82 | if (unlikely(old_pte & H_PAGE_HASHPTE)) { |
883a3e52 | 83 | /* There MIGHT be an HPTE for this pte */ |
bf9a95f9 | 84 | unsigned long gslot; |
883a3e52 | 85 | |
bf9a95f9 RP |
86 | gslot = pte_get_hash_gslot(vpn, shift, ssize, rpte, 0); |
87 | if (mmu_hash_ops.hpte_updatepp(gslot, rflags, vpn, mmu_psize, | |
7025776e | 88 | mmu_psize, ssize, flags) == -1) |
883a3e52 DG |
89 | old_pte &= ~_PAGE_HPTEFLAGS; |
90 | } | |
91 | ||
945537df | 92 | if (likely(!(old_pte & H_PAGE_HASHPTE))) { |
5524a27d | 93 | unsigned long hash = hpt_hash(vpn, shift, ssize); |
883a3e52 DG |
94 | |
95 | pa = pte_pfn(__pte(old_pte)) << PAGE_SHIFT; | |
96 | ||
883a3e52 | 97 | /* clear HPTE slot informations in new PTE */ |
945537df | 98 | new_pte = (new_pte & ~_PAGE_HPTEFLAGS) | H_PAGE_HASHPTE; |
bf680d51 | 99 | |
b170bd3d LZ |
100 | slot = hpte_insert_repeating(hash, vpn, pa, rflags, 0, |
101 | mmu_psize, ssize); | |
883a3e52 | 102 | |
b1623e7e AB |
103 | /* |
104 | * Hypervisor failure. Restore old pte and return -1 | |
105 | * similar to __hash_page_* | |
106 | */ | |
107 | if (unlikely(slot == -2)) { | |
108 | *ptep = __pte(old_pte); | |
4b8692c0 | 109 | hash_failure_debug(ea, access, vsid, trap, ssize, |
d8139ebf | 110 | mmu_psize, mmu_psize, old_pte); |
171aa2ca | 111 | return -1; |
b1623e7e | 112 | } |
883a3e52 | 113 | |
ff31e105 | 114 | new_pte |= pte_set_hidx(ptep, rpte, 0, slot, offset); |
883a3e52 DG |
115 | } |
116 | ||
117 | /* | |
118 | * No need to use ldarx/stdcx here | |
119 | */ | |
945537df | 120 | *ptep = __pte(new_pte & ~H_PAGE_BUSY); |
171aa2ca | 121 | return 0; |
883a3e52 | 122 | } |
8ef5cbde AK |
123 | |
124 | pte_t huge_ptep_modify_prot_start(struct vm_area_struct *vma, | |
125 | unsigned long addr, pte_t *ptep) | |
126 | { | |
127 | unsigned long pte_val; | |
128 | /* | |
129 | * Clear the _PAGE_PRESENT so that no hardware parallel update is | |
130 | * possible. Also keep the pte_present true so that we don't take | |
131 | * wrong fault. | |
132 | */ | |
133 | pte_val = pte_update(vma->vm_mm, addr, ptep, | |
134 | _PAGE_PRESENT, _PAGE_INVALID, 1); | |
135 | ||
136 | return __pte(pte_val); | |
137 | } | |
138 | ||
139 | void huge_ptep_modify_prot_commit(struct vm_area_struct *vma, unsigned long addr, | |
140 | pte_t *ptep, pte_t old_pte, pte_t pte) | |
141 | { | |
142 | ||
143 | if (radix_enabled()) | |
144 | return radix__huge_ptep_modify_prot_commit(vma, addr, ptep, | |
145 | old_pte, pte); | |
146 | set_huge_pte_at(vma->vm_mm, addr, ptep, pte); | |
147 | } |