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a43c0eb8 AK |
1 | /* |
2 | * Copyright IBM Corporation, 2015 | |
3 | * Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or modify it | |
6 | * under the terms of version 2 of the GNU Lesser General Public License | |
7 | * as published by the Free Software Foundation. | |
8 | * | |
9 | * This program is distributed in the hope that it would be useful, but | |
10 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. | |
12 | * | |
13 | */ | |
14 | ||
15 | #include <linux/mm.h> | |
16 | #include <asm/machdep.h> | |
17 | #include <asm/mmu.h> | |
18 | ||
19 | int __hash_page_4K(unsigned long ea, unsigned long access, unsigned long vsid, | |
20 | pte_t *ptep, unsigned long trap, unsigned long flags, | |
21 | int ssize, int subpg_prot) | |
22 | { | |
23 | unsigned long hpte_group; | |
24 | unsigned long rflags, pa; | |
25 | unsigned long old_pte, new_pte; | |
26 | unsigned long vpn, hash, slot; | |
27 | unsigned long shift = mmu_psize_defs[MMU_PAGE_4K].shift; | |
28 | ||
29 | /* | |
30 | * atomically mark the linux large page PTE busy and dirty | |
31 | */ | |
32 | do { | |
33 | pte_t pte = READ_ONCE(*ptep); | |
34 | ||
35 | old_pte = pte_val(pte); | |
36 | /* If PTE busy, retry the access */ | |
945537df | 37 | if (unlikely(old_pte & H_PAGE_BUSY)) |
a43c0eb8 AK |
38 | return 0; |
39 | /* If PTE permissions don't match, take page fault */ | |
ac29c640 | 40 | if (unlikely(!check_pte_access(access, old_pte))) |
a43c0eb8 AK |
41 | return 1; |
42 | /* | |
43 | * Try to lock the PTE, add ACCESSED and DIRTY if it was | |
44 | * a write access. Since this is 4K insert of 64K page size | |
945537df | 45 | * also add H_PAGE_COMBO |
a43c0eb8 | 46 | */ |
945537df | 47 | new_pte = old_pte | H_PAGE_BUSY | _PAGE_ACCESSED; |
c7d54842 | 48 | if (access & _PAGE_WRITE) |
a43c0eb8 | 49 | new_pte |= _PAGE_DIRTY; |
3910a7f4 ME |
50 | } while (!pte_xchg(ptep, __pte(old_pte), __pte(new_pte))); |
51 | ||
a43c0eb8 AK |
52 | /* |
53 | * PP bits. _PAGE_USER is already PP bit 0x2, so we only | |
54 | * need to add in 0x1 if it's a read-only user page | |
55 | */ | |
c6a3c495 | 56 | rflags = htab_convert_pte_flags(new_pte); |
a43c0eb8 AK |
57 | |
58 | if (!cpu_has_feature(CPU_FTR_NOEXECUTE) && | |
59 | !cpu_has_feature(CPU_FTR_COHERENT_ICACHE)) | |
60 | rflags = hash_page_do_lazy_icache(rflags, __pte(old_pte), trap); | |
61 | ||
62 | vpn = hpt_vpn(ea, vsid, ssize); | |
945537df | 63 | if (unlikely(old_pte & H_PAGE_HASHPTE)) { |
a43c0eb8 AK |
64 | /* |
65 | * There MIGHT be an HPTE for this pte | |
66 | */ | |
67 | hash = hpt_hash(vpn, shift, ssize); | |
945537df | 68 | if (old_pte & H_PAGE_F_SECOND) |
a43c0eb8 AK |
69 | hash = ~hash; |
70 | slot = (hash & htab_hash_mask) * HPTES_PER_GROUP; | |
945537df | 71 | slot += (old_pte & H_PAGE_F_GIX) >> H_PAGE_F_GIX_SHIFT; |
a43c0eb8 | 72 | |
7025776e BH |
73 | if (mmu_hash_ops.hpte_updatepp(slot, rflags, vpn, MMU_PAGE_4K, |
74 | MMU_PAGE_4K, ssize, flags) == -1) | |
a43c0eb8 AK |
75 | old_pte &= ~_PAGE_HPTEFLAGS; |
76 | } | |
77 | ||
945537df | 78 | if (likely(!(old_pte & H_PAGE_HASHPTE))) { |
a43c0eb8 AK |
79 | |
80 | pa = pte_pfn(__pte(old_pte)) << PAGE_SHIFT; | |
81 | hash = hpt_hash(vpn, shift, ssize); | |
82 | ||
83 | repeat: | |
84 | hpte_group = ((hash & htab_hash_mask) * HPTES_PER_GROUP) & ~0x7UL; | |
85 | ||
86 | /* Insert into the hash table, primary slot */ | |
7025776e BH |
87 | slot = mmu_hash_ops.hpte_insert(hpte_group, vpn, pa, rflags, 0, |
88 | MMU_PAGE_4K, MMU_PAGE_4K, ssize); | |
a43c0eb8 AK |
89 | /* |
90 | * Primary is full, try the secondary | |
91 | */ | |
92 | if (unlikely(slot == -1)) { | |
93 | hpte_group = ((~hash & htab_hash_mask) * HPTES_PER_GROUP) & ~0x7UL; | |
7025776e BH |
94 | slot = mmu_hash_ops.hpte_insert(hpte_group, vpn, pa, |
95 | rflags, | |
96 | HPTE_V_SECONDARY, | |
97 | MMU_PAGE_4K, | |
98 | MMU_PAGE_4K, ssize); | |
a43c0eb8 AK |
99 | if (slot == -1) { |
100 | if (mftb() & 0x1) | |
101 | hpte_group = ((hash & htab_hash_mask) * | |
102 | HPTES_PER_GROUP) & ~0x7UL; | |
7025776e | 103 | mmu_hash_ops.hpte_remove(hpte_group); |
a43c0eb8 AK |
104 | /* |
105 | * FIXME!! Should be try the group from which we removed ? | |
106 | */ | |
107 | goto repeat; | |
108 | } | |
109 | } | |
110 | /* | |
e9a68147 | 111 | * Hypervisor failure. Restore old pte and return -1 |
a43c0eb8 AK |
112 | * similar to __hash_page_* |
113 | */ | |
114 | if (unlikely(slot == -2)) { | |
115 | *ptep = __pte(old_pte); | |
116 | hash_failure_debug(ea, access, vsid, trap, ssize, | |
117 | MMU_PAGE_4K, MMU_PAGE_4K, old_pte); | |
118 | return -1; | |
119 | } | |
945537df AK |
120 | new_pte = (new_pte & ~_PAGE_HPTEFLAGS) | H_PAGE_HASHPTE; |
121 | new_pte |= (slot << H_PAGE_F_GIX_SHIFT) & | |
122 | (H_PAGE_F_SECOND | H_PAGE_F_GIX); | |
a43c0eb8 | 123 | } |
945537df | 124 | *ptep = __pte(new_pte & ~H_PAGE_BUSY); |
a43c0eb8 AK |
125 | return 0; |
126 | } |