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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 */ | |
37 | if (unlikely(old_pte & _PAGE_BUSY)) | |
38 | return 0; | |
39 | /* If PTE permissions don't match, take page fault */ | |
40 | if (unlikely(access & ~old_pte)) | |
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 | |
45 | * also add _PAGE_COMBO | |
46 | */ | |
c367a441 | 47 | new_pte = old_pte | _PAGE_BUSY | _PAGE_ACCESSED; |
a43c0eb8 AK |
48 | if (access & _PAGE_RW) |
49 | new_pte |= _PAGE_DIRTY; | |
50 | } while (old_pte != __cmpxchg_u64((unsigned long *)ptep, | |
51 | old_pte, new_pte)); | |
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); | |
63 | if (unlikely(old_pte & _PAGE_HASHPTE)) { | |
64 | /* | |
65 | * There MIGHT be an HPTE for this pte | |
66 | */ | |
67 | hash = hpt_hash(vpn, shift, ssize); | |
68 | if (old_pte & _PAGE_F_SECOND) | |
69 | hash = ~hash; | |
70 | slot = (hash & htab_hash_mask) * HPTES_PER_GROUP; | |
71 | slot += (old_pte & _PAGE_F_GIX) >> _PAGE_F_GIX_SHIFT; | |
72 | ||
73 | if (ppc_md.hpte_updatepp(slot, rflags, vpn, MMU_PAGE_4K, | |
74 | MMU_PAGE_4K, ssize, flags) == -1) | |
75 | old_pte &= ~_PAGE_HPTEFLAGS; | |
76 | } | |
77 | ||
78 | if (likely(!(old_pte & _PAGE_HASHPTE))) { | |
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 */ | |
87 | slot = ppc_md.hpte_insert(hpte_group, vpn, pa, rflags, 0, | |
88 | MMU_PAGE_4K, MMU_PAGE_4K, ssize); | |
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; | |
94 | slot = ppc_md.hpte_insert(hpte_group, vpn, pa, | |
95 | rflags, HPTE_V_SECONDARY, | |
96 | MMU_PAGE_4K, MMU_PAGE_4K, ssize); | |
97 | if (slot == -1) { | |
98 | if (mftb() & 0x1) | |
99 | hpte_group = ((hash & htab_hash_mask) * | |
100 | HPTES_PER_GROUP) & ~0x7UL; | |
101 | ppc_md.hpte_remove(hpte_group); | |
102 | /* | |
103 | * FIXME!! Should be try the group from which we removed ? | |
104 | */ | |
105 | goto repeat; | |
106 | } | |
107 | } | |
108 | /* | |
e9a68147 | 109 | * Hypervisor failure. Restore old pte and return -1 |
a43c0eb8 AK |
110 | * similar to __hash_page_* |
111 | */ | |
112 | if (unlikely(slot == -2)) { | |
113 | *ptep = __pte(old_pte); | |
114 | hash_failure_debug(ea, access, vsid, trap, ssize, | |
115 | MMU_PAGE_4K, MMU_PAGE_4K, old_pte); | |
116 | return -1; | |
117 | } | |
118 | new_pte = (new_pte & ~_PAGE_HPTEFLAGS) | _PAGE_HASHPTE; | |
119 | new_pte |= (slot << _PAGE_F_GIX_SHIFT) & (_PAGE_F_SECOND | _PAGE_F_GIX); | |
120 | } | |
121 | *ptep = __pte(new_pte & ~_PAGE_BUSY); | |
122 | return 0; | |
123 | } |