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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 | { | |
a8548686 | 23 | real_pte_t rpte; |
a43c0eb8 AK |
24 | unsigned long hpte_group; |
25 | unsigned long rflags, pa; | |
26 | unsigned long old_pte, new_pte; | |
27 | unsigned long vpn, hash, slot; | |
28 | unsigned long shift = mmu_psize_defs[MMU_PAGE_4K].shift; | |
29 | ||
30 | /* | |
31 | * atomically mark the linux large page PTE busy and dirty | |
32 | */ | |
33 | do { | |
34 | pte_t pte = READ_ONCE(*ptep); | |
35 | ||
36 | old_pte = pte_val(pte); | |
37 | /* If PTE busy, retry the access */ | |
945537df | 38 | if (unlikely(old_pte & H_PAGE_BUSY)) |
a43c0eb8 AK |
39 | return 0; |
40 | /* If PTE permissions don't match, take page fault */ | |
ac29c640 | 41 | if (unlikely(!check_pte_access(access, old_pte))) |
a43c0eb8 AK |
42 | return 1; |
43 | /* | |
44 | * Try to lock the PTE, add ACCESSED and DIRTY if it was | |
45 | * a write access. Since this is 4K insert of 64K page size | |
945537df | 46 | * also add H_PAGE_COMBO |
a43c0eb8 | 47 | */ |
945537df | 48 | new_pte = old_pte | H_PAGE_BUSY | _PAGE_ACCESSED; |
c7d54842 | 49 | if (access & _PAGE_WRITE) |
a43c0eb8 | 50 | new_pte |= _PAGE_DIRTY; |
3910a7f4 ME |
51 | } while (!pte_xchg(ptep, __pte(old_pte), __pte(new_pte))); |
52 | ||
a43c0eb8 AK |
53 | /* |
54 | * PP bits. _PAGE_USER is already PP bit 0x2, so we only | |
55 | * need to add in 0x1 if it's a read-only user page | |
56 | */ | |
c6a3c495 | 57 | rflags = htab_convert_pte_flags(new_pte); |
ff31e105 | 58 | rpte = __real_pte(__pte(old_pte), ptep, PTRS_PER_PTE); |
a43c0eb8 | 59 | |
dd7b2f03 | 60 | if (cpu_has_feature(CPU_FTR_NOEXECUTE) && |
a43c0eb8 AK |
61 | !cpu_has_feature(CPU_FTR_COHERENT_ICACHE)) |
62 | rflags = hash_page_do_lazy_icache(rflags, __pte(old_pte), trap); | |
63 | ||
64 | vpn = hpt_vpn(ea, vsid, ssize); | |
945537df | 65 | if (unlikely(old_pte & H_PAGE_HASHPTE)) { |
a43c0eb8 AK |
66 | /* |
67 | * There MIGHT be an HPTE for this pte | |
68 | */ | |
a8548686 RP |
69 | unsigned long gslot = pte_get_hash_gslot(vpn, shift, ssize, |
70 | rpte, 0); | |
a43c0eb8 | 71 | |
a8548686 | 72 | if (mmu_hash_ops.hpte_updatepp(gslot, rflags, vpn, MMU_PAGE_4K, |
7025776e | 73 | MMU_PAGE_4K, ssize, flags) == -1) |
a43c0eb8 AK |
74 | old_pte &= ~_PAGE_HPTEFLAGS; |
75 | } | |
76 | ||
945537df | 77 | if (likely(!(old_pte & H_PAGE_HASHPTE))) { |
a43c0eb8 AK |
78 | |
79 | pa = pte_pfn(__pte(old_pte)) << PAGE_SHIFT; | |
80 | hash = hpt_hash(vpn, shift, ssize); | |
81 | ||
82 | repeat: | |
1531cff4 | 83 | hpte_group = (hash & htab_hash_mask) * HPTES_PER_GROUP; |
a43c0eb8 AK |
84 | |
85 | /* Insert into the hash table, primary slot */ | |
7025776e BH |
86 | slot = mmu_hash_ops.hpte_insert(hpte_group, vpn, pa, rflags, 0, |
87 | MMU_PAGE_4K, MMU_PAGE_4K, ssize); | |
a43c0eb8 AK |
88 | /* |
89 | * Primary is full, try the secondary | |
90 | */ | |
91 | if (unlikely(slot == -1)) { | |
1531cff4 | 92 | hpte_group = (~hash & htab_hash_mask) * HPTES_PER_GROUP; |
7025776e BH |
93 | slot = mmu_hash_ops.hpte_insert(hpte_group, vpn, pa, |
94 | rflags, | |
95 | HPTE_V_SECONDARY, | |
96 | MMU_PAGE_4K, | |
97 | MMU_PAGE_4K, ssize); | |
a43c0eb8 AK |
98 | if (slot == -1) { |
99 | if (mftb() & 0x1) | |
1531cff4 AK |
100 | hpte_group = (hash & htab_hash_mask) * |
101 | HPTES_PER_GROUP; | |
7025776e | 102 | mmu_hash_ops.hpte_remove(hpte_group); |
a43c0eb8 AK |
103 | /* |
104 | * FIXME!! Should be try the group from which we removed ? | |
105 | */ | |
106 | goto repeat; | |
107 | } | |
108 | } | |
109 | /* | |
e9a68147 | 110 | * Hypervisor failure. Restore old pte and return -1 |
a43c0eb8 AK |
111 | * similar to __hash_page_* |
112 | */ | |
113 | if (unlikely(slot == -2)) { | |
114 | *ptep = __pte(old_pte); | |
115 | hash_failure_debug(ea, access, vsid, trap, ssize, | |
116 | MMU_PAGE_4K, MMU_PAGE_4K, old_pte); | |
117 | return -1; | |
118 | } | |
945537df | 119 | new_pte = (new_pte & ~_PAGE_HPTEFLAGS) | H_PAGE_HASHPTE; |
ff31e105 | 120 | new_pte |= pte_set_hidx(ptep, rpte, 0, slot, PTRS_PER_PTE); |
a43c0eb8 | 121 | } |
945537df | 122 | *ptep = __pte(new_pte & ~H_PAGE_BUSY); |
a43c0eb8 AK |
123 | return 0; |
124 | } |