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1/*
2 * IBM System z Huge TLB Page Support for Kernel.
3 *
4 * Copyright 2007 IBM Corp.
5 * Author(s): Gerald Schaefer <gerald.schaefer@de.ibm.com>
6 */
7
8#include <linux/mm.h>
9#include <linux/hugetlb.h>
10
11
12void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
13 pte_t *pteptr, pte_t pteval)
14{
15 pmd_t *pmdp = (pmd_t *) pteptr;
16 unsigned long mask;
17
18 if (!MACHINE_HAS_HPAGE) {
19 pteptr = (pte_t *) pte_page(pteval)[1].index;
20 mask = pte_val(pteval) &
21 (_SEGMENT_ENTRY_INV | _SEGMENT_ENTRY_RO);
22 pte_val(pteval) = (_SEGMENT_ENTRY + __pa(pteptr)) | mask;
23 }
24
25 pmd_val(*pmdp) = pte_val(pteval);
26}
27
28int arch_prepare_hugepage(struct page *page)
29{
30 unsigned long addr = page_to_phys(page);
31 pte_t pte;
32 pte_t *ptep;
33 int i;
34
35 if (MACHINE_HAS_HPAGE)
36 return 0;
37
38 ptep = (pte_t *) pte_alloc_one(&init_mm, addr);
39 if (!ptep)
40 return -ENOMEM;
41
42 pte = mk_pte(page, PAGE_RW);
43 for (i = 0; i < PTRS_PER_PTE; i++) {
44 set_pte_at(&init_mm, addr + i * PAGE_SIZE, ptep + i, pte);
45 pte_val(pte) += PAGE_SIZE;
46 }
47 page[1].index = (unsigned long) ptep;
48 return 0;
49}
50
51void arch_release_hugepage(struct page *page)
52{
53 pte_t *ptep;
54
55 if (MACHINE_HAS_HPAGE)
56 return;
57
58 ptep = (pte_t *) page[1].index;
59 if (!ptep)
60 return;
61 clear_table((unsigned long *) ptep, _PAGE_TYPE_EMPTY,
62 PTRS_PER_PTE * sizeof(pte_t));
63 page_table_free(&init_mm, (unsigned long *) ptep);
64 page[1].index = 0;
65}
66
67pte_t *huge_pte_alloc(struct mm_struct *mm,
68 unsigned long addr, unsigned long sz)
69{
70 pgd_t *pgdp;
71 pud_t *pudp;
72 pmd_t *pmdp = NULL;
73
74 pgdp = pgd_offset(mm, addr);
75 pudp = pud_alloc(mm, pgdp, addr);
76 if (pudp)
77 pmdp = pmd_alloc(mm, pudp, addr);
78 return (pte_t *) pmdp;
79}
80
81pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
82{
83 pgd_t *pgdp;
84 pud_t *pudp;
85 pmd_t *pmdp = NULL;
86
87 pgdp = pgd_offset(mm, addr);
88 if (pgd_present(*pgdp)) {
89 pudp = pud_offset(pgdp, addr);
90 if (pud_present(*pudp))
91 pmdp = pmd_offset(pudp, addr);
92 }
93 return (pte_t *) pmdp;
94}
95
96int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
97{
98 return 0;
99}
100
101struct page *follow_huge_addr(struct mm_struct *mm, unsigned long address,
102 int write)
103{
104 return ERR_PTR(-EINVAL);
105}
106
107int pmd_huge(pmd_t pmd)
108{
109 if (!MACHINE_HAS_HPAGE)
110 return 0;
111
112 return !!(pmd_val(pmd) & _SEGMENT_ENTRY_LARGE);
113}
114
115int pud_huge(pud_t pud)
116{
117 return 0;
118}
119
120struct page *follow_huge_pmd(struct mm_struct *mm, unsigned long address,
121 pmd_t *pmdp, int write)
122{
123 struct page *page;
124
125 if (!MACHINE_HAS_HPAGE)
126 return NULL;
127
128 page = pmd_page(*pmdp);
129 if (page)
130 page += ((address & ~HPAGE_MASK) >> PAGE_SHIFT);
131 return page;
132}
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * IBM System z Huge TLB Page Support for Kernel.
4 *
5 * Copyright IBM Corp. 2007,2016
6 * Author(s): Gerald Schaefer <gerald.schaefer@de.ibm.com>
7 */
8
9#define KMSG_COMPONENT "hugetlb"
10#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
11
12#include <linux/mm.h>
13#include <linux/hugetlb.h>
14
15/*
16 * If the bit selected by single-bit bitmask "a" is set within "x", move
17 * it to the position indicated by single-bit bitmask "b".
18 */
19#define move_set_bit(x, a, b) (((x) & (a)) >> ilog2(a) << ilog2(b))
20
21static inline unsigned long __pte_to_rste(pte_t pte)
22{
23 unsigned long rste;
24
25 /*
26 * Convert encoding pte bits pmd / pud bits
27 * lIR.uswrdy.p dy..R...I...wr
28 * empty 010.000000.0 -> 00..0...1...00
29 * prot-none, clean, old 111.000000.1 -> 00..1...1...00
30 * prot-none, clean, young 111.000001.1 -> 01..1...1...00
31 * prot-none, dirty, old 111.000010.1 -> 10..1...1...00
32 * prot-none, dirty, young 111.000011.1 -> 11..1...1...00
33 * read-only, clean, old 111.000100.1 -> 00..1...1...01
34 * read-only, clean, young 101.000101.1 -> 01..1...0...01
35 * read-only, dirty, old 111.000110.1 -> 10..1...1...01
36 * read-only, dirty, young 101.000111.1 -> 11..1...0...01
37 * read-write, clean, old 111.001100.1 -> 00..1...1...11
38 * read-write, clean, young 101.001101.1 -> 01..1...0...11
39 * read-write, dirty, old 110.001110.1 -> 10..0...1...11
40 * read-write, dirty, young 100.001111.1 -> 11..0...0...11
41 * HW-bits: R read-only, I invalid
42 * SW-bits: p present, y young, d dirty, r read, w write, s special,
43 * u unused, l large
44 */
45 if (pte_present(pte)) {
46 rste = pte_val(pte) & PAGE_MASK;
47 rste |= move_set_bit(pte_val(pte), _PAGE_READ,
48 _SEGMENT_ENTRY_READ);
49 rste |= move_set_bit(pte_val(pte), _PAGE_WRITE,
50 _SEGMENT_ENTRY_WRITE);
51 rste |= move_set_bit(pte_val(pte), _PAGE_INVALID,
52 _SEGMENT_ENTRY_INVALID);
53 rste |= move_set_bit(pte_val(pte), _PAGE_PROTECT,
54 _SEGMENT_ENTRY_PROTECT);
55 rste |= move_set_bit(pte_val(pte), _PAGE_DIRTY,
56 _SEGMENT_ENTRY_DIRTY);
57 rste |= move_set_bit(pte_val(pte), _PAGE_YOUNG,
58 _SEGMENT_ENTRY_YOUNG);
59#ifdef CONFIG_MEM_SOFT_DIRTY
60 rste |= move_set_bit(pte_val(pte), _PAGE_SOFT_DIRTY,
61 _SEGMENT_ENTRY_SOFT_DIRTY);
62#endif
63 rste |= move_set_bit(pte_val(pte), _PAGE_NOEXEC,
64 _SEGMENT_ENTRY_NOEXEC);
65 } else
66 rste = _SEGMENT_ENTRY_EMPTY;
67 return rste;
68}
69
70static inline pte_t __rste_to_pte(unsigned long rste)
71{
72 int present;
73 pte_t pte;
74
75 if ((rste & _REGION_ENTRY_TYPE_MASK) == _REGION_ENTRY_TYPE_R3)
76 present = pud_present(__pud(rste));
77 else
78 present = pmd_present(__pmd(rste));
79
80 /*
81 * Convert encoding pmd / pud bits pte bits
82 * dy..R...I...wr lIR.uswrdy.p
83 * empty 00..0...1...00 -> 010.000000.0
84 * prot-none, clean, old 00..1...1...00 -> 111.000000.1
85 * prot-none, clean, young 01..1...1...00 -> 111.000001.1
86 * prot-none, dirty, old 10..1...1...00 -> 111.000010.1
87 * prot-none, dirty, young 11..1...1...00 -> 111.000011.1
88 * read-only, clean, old 00..1...1...01 -> 111.000100.1
89 * read-only, clean, young 01..1...0...01 -> 101.000101.1
90 * read-only, dirty, old 10..1...1...01 -> 111.000110.1
91 * read-only, dirty, young 11..1...0...01 -> 101.000111.1
92 * read-write, clean, old 00..1...1...11 -> 111.001100.1
93 * read-write, clean, young 01..1...0...11 -> 101.001101.1
94 * read-write, dirty, old 10..0...1...11 -> 110.001110.1
95 * read-write, dirty, young 11..0...0...11 -> 100.001111.1
96 * HW-bits: R read-only, I invalid
97 * SW-bits: p present, y young, d dirty, r read, w write, s special,
98 * u unused, l large
99 */
100 if (present) {
101 pte_val(pte) = rste & _SEGMENT_ENTRY_ORIGIN_LARGE;
102 pte_val(pte) |= _PAGE_LARGE | _PAGE_PRESENT;
103 pte_val(pte) |= move_set_bit(rste, _SEGMENT_ENTRY_READ,
104 _PAGE_READ);
105 pte_val(pte) |= move_set_bit(rste, _SEGMENT_ENTRY_WRITE,
106 _PAGE_WRITE);
107 pte_val(pte) |= move_set_bit(rste, _SEGMENT_ENTRY_INVALID,
108 _PAGE_INVALID);
109 pte_val(pte) |= move_set_bit(rste, _SEGMENT_ENTRY_PROTECT,
110 _PAGE_PROTECT);
111 pte_val(pte) |= move_set_bit(rste, _SEGMENT_ENTRY_DIRTY,
112 _PAGE_DIRTY);
113 pte_val(pte) |= move_set_bit(rste, _SEGMENT_ENTRY_YOUNG,
114 _PAGE_YOUNG);
115#ifdef CONFIG_MEM_SOFT_DIRTY
116 pte_val(pte) |= move_set_bit(rste, _SEGMENT_ENTRY_SOFT_DIRTY,
117 _PAGE_DIRTY);
118#endif
119 pte_val(pte) |= move_set_bit(rste, _SEGMENT_ENTRY_NOEXEC,
120 _PAGE_NOEXEC);
121 } else
122 pte_val(pte) = _PAGE_INVALID;
123 return pte;
124}
125
126void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
127 pte_t *ptep, pte_t pte)
128{
129 unsigned long rste;
130
131 rste = __pte_to_rste(pte);
132 if (!MACHINE_HAS_NX)
133 rste &= ~_SEGMENT_ENTRY_NOEXEC;
134
135 /* Set correct table type for 2G hugepages */
136 if ((pte_val(*ptep) & _REGION_ENTRY_TYPE_MASK) == _REGION_ENTRY_TYPE_R3)
137 rste |= _REGION_ENTRY_TYPE_R3 | _REGION3_ENTRY_LARGE;
138 else
139 rste |= _SEGMENT_ENTRY_LARGE;
140 pte_val(*ptep) = rste;
141}
142
143pte_t huge_ptep_get(pte_t *ptep)
144{
145 return __rste_to_pte(pte_val(*ptep));
146}
147
148pte_t huge_ptep_get_and_clear(struct mm_struct *mm,
149 unsigned long addr, pte_t *ptep)
150{
151 pte_t pte = huge_ptep_get(ptep);
152 pmd_t *pmdp = (pmd_t *) ptep;
153 pud_t *pudp = (pud_t *) ptep;
154
155 if ((pte_val(*ptep) & _REGION_ENTRY_TYPE_MASK) == _REGION_ENTRY_TYPE_R3)
156 pudp_xchg_direct(mm, addr, pudp, __pud(_REGION3_ENTRY_EMPTY));
157 else
158 pmdp_xchg_direct(mm, addr, pmdp, __pmd(_SEGMENT_ENTRY_EMPTY));
159 return pte;
160}
161
162pte_t *huge_pte_alloc(struct mm_struct *mm,
163 unsigned long addr, unsigned long sz)
164{
165 pgd_t *pgdp;
166 p4d_t *p4dp;
167 pud_t *pudp;
168 pmd_t *pmdp = NULL;
169
170 pgdp = pgd_offset(mm, addr);
171 p4dp = p4d_alloc(mm, pgdp, addr);
172 if (p4dp) {
173 pudp = pud_alloc(mm, p4dp, addr);
174 if (pudp) {
175 if (sz == PUD_SIZE)
176 return (pte_t *) pudp;
177 else if (sz == PMD_SIZE)
178 pmdp = pmd_alloc(mm, pudp, addr);
179 }
180 }
181 return (pte_t *) pmdp;
182}
183
184pte_t *huge_pte_offset(struct mm_struct *mm,
185 unsigned long addr, unsigned long sz)
186{
187 pgd_t *pgdp;
188 p4d_t *p4dp;
189 pud_t *pudp;
190 pmd_t *pmdp = NULL;
191
192 pgdp = pgd_offset(mm, addr);
193 if (pgd_present(*pgdp)) {
194 p4dp = p4d_offset(pgdp, addr);
195 if (p4d_present(*p4dp)) {
196 pudp = pud_offset(p4dp, addr);
197 if (pud_present(*pudp)) {
198 if (pud_large(*pudp))
199 return (pte_t *) pudp;
200 pmdp = pmd_offset(pudp, addr);
201 }
202 }
203 }
204 return (pte_t *) pmdp;
205}
206
207int pmd_huge(pmd_t pmd)
208{
209 return pmd_large(pmd);
210}
211
212int pud_huge(pud_t pud)
213{
214 return pud_large(pud);
215}
216
217struct page *
218follow_huge_pud(struct mm_struct *mm, unsigned long address,
219 pud_t *pud, int flags)
220{
221 if (flags & FOLL_GET)
222 return NULL;
223
224 return pud_page(*pud) + ((address & ~PUD_MASK) >> PAGE_SHIFT);
225}
226
227static __init int setup_hugepagesz(char *opt)
228{
229 unsigned long size;
230 char *string = opt;
231
232 size = memparse(opt, &opt);
233 if (MACHINE_HAS_EDAT1 && size == PMD_SIZE) {
234 hugetlb_add_hstate(PMD_SHIFT - PAGE_SHIFT);
235 } else if (MACHINE_HAS_EDAT2 && size == PUD_SIZE) {
236 hugetlb_add_hstate(PUD_SHIFT - PAGE_SHIFT);
237 } else {
238 hugetlb_bad_size();
239 pr_err("hugepagesz= specifies an unsupported page size %s\n",
240 string);
241 return 0;
242 }
243 return 1;
244}
245__setup("hugepagesz=", setup_hugepagesz);