GNU Linux-libre 4.19.314-gnu1
[releases.git] / arch / s390 / mm / hugetlbpage.c
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  *  IBM System z Huge TLB Page Support for Kernel.
4  *
5  *    Copyright IBM Corp. 2007,2020
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 #include <linux/mman.h>
15 #include <linux/sched/mm.h>
16 #include <linux/security.h>
17
18 /*
19  * If the bit selected by single-bit bitmask "a" is set within "x", move
20  * it to the position indicated by single-bit bitmask "b".
21  */
22 #define move_set_bit(x, a, b)   (((x) & (a)) >> ilog2(a) << ilog2(b))
23
24 static inline unsigned long __pte_to_rste(pte_t pte)
25 {
26         unsigned long rste;
27
28         /*
29          * Convert encoding               pte bits      pmd / pud bits
30          *                              lIR.uswrdy.p    dy..R...I...wr
31          * empty                        010.000000.0 -> 00..0...1...00
32          * prot-none, clean, old        111.000000.1 -> 00..1...1...00
33          * prot-none, clean, young      111.000001.1 -> 01..1...1...00
34          * prot-none, dirty, old        111.000010.1 -> 10..1...1...00
35          * prot-none, dirty, young      111.000011.1 -> 11..1...1...00
36          * read-only, clean, old        111.000100.1 -> 00..1...1...01
37          * read-only, clean, young      101.000101.1 -> 01..1...0...01
38          * read-only, dirty, old        111.000110.1 -> 10..1...1...01
39          * read-only, dirty, young      101.000111.1 -> 11..1...0...01
40          * read-write, clean, old       111.001100.1 -> 00..1...1...11
41          * read-write, clean, young     101.001101.1 -> 01..1...0...11
42          * read-write, dirty, old       110.001110.1 -> 10..0...1...11
43          * read-write, dirty, young     100.001111.1 -> 11..0...0...11
44          * HW-bits: R read-only, I invalid
45          * SW-bits: p present, y young, d dirty, r read, w write, s special,
46          *          u unused, l large
47          */
48         if (pte_present(pte)) {
49                 rste = pte_val(pte) & PAGE_MASK;
50                 rste |= move_set_bit(pte_val(pte), _PAGE_READ,
51                                      _SEGMENT_ENTRY_READ);
52                 rste |= move_set_bit(pte_val(pte), _PAGE_WRITE,
53                                      _SEGMENT_ENTRY_WRITE);
54                 rste |= move_set_bit(pte_val(pte), _PAGE_INVALID,
55                                      _SEGMENT_ENTRY_INVALID);
56                 rste |= move_set_bit(pte_val(pte), _PAGE_PROTECT,
57                                      _SEGMENT_ENTRY_PROTECT);
58                 rste |= move_set_bit(pte_val(pte), _PAGE_DIRTY,
59                                      _SEGMENT_ENTRY_DIRTY);
60                 rste |= move_set_bit(pte_val(pte), _PAGE_YOUNG,
61                                      _SEGMENT_ENTRY_YOUNG);
62 #ifdef CONFIG_MEM_SOFT_DIRTY
63                 rste |= move_set_bit(pte_val(pte), _PAGE_SOFT_DIRTY,
64                                      _SEGMENT_ENTRY_SOFT_DIRTY);
65 #endif
66                 rste |= move_set_bit(pte_val(pte), _PAGE_NOEXEC,
67                                      _SEGMENT_ENTRY_NOEXEC);
68         } else
69                 rste = _SEGMENT_ENTRY_EMPTY;
70         return rste;
71 }
72
73 static inline pte_t __rste_to_pte(unsigned long rste)
74 {
75         int present;
76         pte_t pte;
77
78         if ((rste & _REGION_ENTRY_TYPE_MASK) == _REGION_ENTRY_TYPE_R3)
79                 present = pud_present(__pud(rste));
80         else
81                 present = pmd_present(__pmd(rste));
82
83         /*
84          * Convert encoding             pmd / pud bits      pte bits
85          *                              dy..R...I...wr    lIR.uswrdy.p
86          * empty                        00..0...1...00 -> 010.000000.0
87          * prot-none, clean, old        00..1...1...00 -> 111.000000.1
88          * prot-none, clean, young      01..1...1...00 -> 111.000001.1
89          * prot-none, dirty, old        10..1...1...00 -> 111.000010.1
90          * prot-none, dirty, young      11..1...1...00 -> 111.000011.1
91          * read-only, clean, old        00..1...1...01 -> 111.000100.1
92          * read-only, clean, young      01..1...0...01 -> 101.000101.1
93          * read-only, dirty, old        10..1...1...01 -> 111.000110.1
94          * read-only, dirty, young      11..1...0...01 -> 101.000111.1
95          * read-write, clean, old       00..1...1...11 -> 111.001100.1
96          * read-write, clean, young     01..1...0...11 -> 101.001101.1
97          * read-write, dirty, old       10..0...1...11 -> 110.001110.1
98          * read-write, dirty, young     11..0...0...11 -> 100.001111.1
99          * HW-bits: R read-only, I invalid
100          * SW-bits: p present, y young, d dirty, r read, w write, s special,
101          *          u unused, l large
102          */
103         if (present) {
104                 pte_val(pte) = rste & _SEGMENT_ENTRY_ORIGIN_LARGE;
105                 pte_val(pte) |= _PAGE_LARGE | _PAGE_PRESENT;
106                 pte_val(pte) |= move_set_bit(rste, _SEGMENT_ENTRY_READ,
107                                              _PAGE_READ);
108                 pte_val(pte) |= move_set_bit(rste, _SEGMENT_ENTRY_WRITE,
109                                              _PAGE_WRITE);
110                 pte_val(pte) |= move_set_bit(rste, _SEGMENT_ENTRY_INVALID,
111                                              _PAGE_INVALID);
112                 pte_val(pte) |= move_set_bit(rste, _SEGMENT_ENTRY_PROTECT,
113                                              _PAGE_PROTECT);
114                 pte_val(pte) |= move_set_bit(rste, _SEGMENT_ENTRY_DIRTY,
115                                              _PAGE_DIRTY);
116                 pte_val(pte) |= move_set_bit(rste, _SEGMENT_ENTRY_YOUNG,
117                                              _PAGE_YOUNG);
118 #ifdef CONFIG_MEM_SOFT_DIRTY
119                 pte_val(pte) |= move_set_bit(rste, _SEGMENT_ENTRY_SOFT_DIRTY,
120                                              _PAGE_SOFT_DIRTY);
121 #endif
122                 pte_val(pte) |= move_set_bit(rste, _SEGMENT_ENTRY_NOEXEC,
123                                              _PAGE_NOEXEC);
124         } else
125                 pte_val(pte) = _PAGE_INVALID;
126         return pte;
127 }
128
129 static void clear_huge_pte_skeys(struct mm_struct *mm, unsigned long rste)
130 {
131         struct page *page;
132         unsigned long size, paddr;
133
134         if (!mm_uses_skeys(mm) ||
135             rste & _SEGMENT_ENTRY_INVALID)
136                 return;
137
138         if ((rste & _REGION_ENTRY_TYPE_MASK) == _REGION_ENTRY_TYPE_R3) {
139                 page = pud_page(__pud(rste));
140                 size = PUD_SIZE;
141                 paddr = rste & PUD_MASK;
142         } else {
143                 page = pmd_page(__pmd(rste));
144                 size = PMD_SIZE;
145                 paddr = rste & PMD_MASK;
146         }
147
148         if (!test_and_set_bit(PG_arch_1, &page->flags))
149                 __storage_key_init_range(paddr, paddr + size);
150 }
151
152 void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
153                      pte_t *ptep, pte_t pte)
154 {
155         unsigned long rste;
156
157         rste = __pte_to_rste(pte);
158         if (!MACHINE_HAS_NX)
159                 rste &= ~_SEGMENT_ENTRY_NOEXEC;
160
161         /* Set correct table type for 2G hugepages */
162         if ((pte_val(*ptep) & _REGION_ENTRY_TYPE_MASK) == _REGION_ENTRY_TYPE_R3) {
163                 if (likely(pte_present(pte)))
164                         rste |= _REGION3_ENTRY_LARGE;
165                 rste |= _REGION_ENTRY_TYPE_R3;
166         } else if (likely(pte_present(pte)))
167                 rste |= _SEGMENT_ENTRY_LARGE;
168
169         clear_huge_pte_skeys(mm, rste);
170         pte_val(*ptep) = rste;
171 }
172
173 pte_t huge_ptep_get(pte_t *ptep)
174 {
175         return __rste_to_pte(pte_val(*ptep));
176 }
177
178 pte_t huge_ptep_get_and_clear(struct mm_struct *mm,
179                               unsigned long addr, pte_t *ptep)
180 {
181         pte_t pte = huge_ptep_get(ptep);
182         pmd_t *pmdp = (pmd_t *) ptep;
183         pud_t *pudp = (pud_t *) ptep;
184
185         if ((pte_val(*ptep) & _REGION_ENTRY_TYPE_MASK) == _REGION_ENTRY_TYPE_R3)
186                 pudp_xchg_direct(mm, addr, pudp, __pud(_REGION3_ENTRY_EMPTY));
187         else
188                 pmdp_xchg_direct(mm, addr, pmdp, __pmd(_SEGMENT_ENTRY_EMPTY));
189         return pte;
190 }
191
192 pte_t *huge_pte_alloc(struct mm_struct *mm,
193                         unsigned long addr, unsigned long sz)
194 {
195         pgd_t *pgdp;
196         p4d_t *p4dp;
197         pud_t *pudp;
198         pmd_t *pmdp = NULL;
199
200         pgdp = pgd_offset(mm, addr);
201         p4dp = p4d_alloc(mm, pgdp, addr);
202         if (p4dp) {
203                 pudp = pud_alloc(mm, p4dp, addr);
204                 if (pudp) {
205                         if (sz == PUD_SIZE)
206                                 return (pte_t *) pudp;
207                         else if (sz == PMD_SIZE)
208                                 pmdp = pmd_alloc(mm, pudp, addr);
209                 }
210         }
211         return (pte_t *) pmdp;
212 }
213
214 pte_t *huge_pte_offset(struct mm_struct *mm,
215                        unsigned long addr, unsigned long sz)
216 {
217         pgd_t *pgdp;
218         p4d_t *p4dp;
219         pud_t *pudp;
220         pmd_t *pmdp = NULL;
221
222         pgdp = pgd_offset(mm, addr);
223         if (pgd_present(*pgdp)) {
224                 p4dp = p4d_offset(pgdp, addr);
225                 if (p4d_present(*p4dp)) {
226                         pudp = pud_offset(p4dp, addr);
227                         if (pud_present(*pudp)) {
228                                 if (pud_large(*pudp))
229                                         return (pte_t *) pudp;
230                                 pmdp = pmd_offset(pudp, addr);
231                         }
232                 }
233         }
234         return (pte_t *) pmdp;
235 }
236
237 int pmd_huge(pmd_t pmd)
238 {
239         return pmd_large(pmd);
240 }
241
242 int pud_huge(pud_t pud)
243 {
244         return pud_large(pud);
245 }
246
247 struct page *
248 follow_huge_pud(struct mm_struct *mm, unsigned long address,
249                 pud_t *pud, int flags)
250 {
251         if (flags & FOLL_GET)
252                 return NULL;
253
254         return pud_page(*pud) + ((address & ~PUD_MASK) >> PAGE_SHIFT);
255 }
256
257 static __init int setup_hugepagesz(char *opt)
258 {
259         unsigned long size;
260         char *string = opt;
261
262         size = memparse(opt, &opt);
263         if (MACHINE_HAS_EDAT1 && size == PMD_SIZE) {
264                 hugetlb_add_hstate(PMD_SHIFT - PAGE_SHIFT);
265         } else if (MACHINE_HAS_EDAT2 && size == PUD_SIZE) {
266                 hugetlb_add_hstate(PUD_SHIFT - PAGE_SHIFT);
267         } else {
268                 hugetlb_bad_size();
269                 pr_err("hugepagesz= specifies an unsupported page size %s\n",
270                         string);
271                 return 0;
272         }
273         return 1;
274 }
275 __setup("hugepagesz=", setup_hugepagesz);
276
277 static unsigned long hugetlb_get_unmapped_area_bottomup(struct file *file,
278                 unsigned long addr, unsigned long len,
279                 unsigned long pgoff, unsigned long flags)
280 {
281         struct hstate *h = hstate_file(file);
282         struct vm_unmapped_area_info info;
283
284         info.flags = 0;
285         info.length = len;
286         info.low_limit = current->mm->mmap_base;
287         info.high_limit = TASK_SIZE;
288         info.align_mask = PAGE_MASK & ~huge_page_mask(h);
289         info.align_offset = 0;
290         return vm_unmapped_area(&info);
291 }
292
293 static unsigned long hugetlb_get_unmapped_area_topdown(struct file *file,
294                 unsigned long addr0, unsigned long len,
295                 unsigned long pgoff, unsigned long flags)
296 {
297         struct hstate *h = hstate_file(file);
298         struct vm_unmapped_area_info info;
299         unsigned long addr;
300
301         info.flags = VM_UNMAPPED_AREA_TOPDOWN;
302         info.length = len;
303         info.low_limit = max(PAGE_SIZE, mmap_min_addr);
304         info.high_limit = current->mm->mmap_base;
305         info.align_mask = PAGE_MASK & ~huge_page_mask(h);
306         info.align_offset = 0;
307         addr = vm_unmapped_area(&info);
308
309         /*
310          * A failed mmap() very likely causes application failure,
311          * so fall back to the bottom-up function here. This scenario
312          * can happen with large stack limits and large mmap()
313          * allocations.
314          */
315         if (addr & ~PAGE_MASK) {
316                 VM_BUG_ON(addr != -ENOMEM);
317                 info.flags = 0;
318                 info.low_limit = TASK_UNMAPPED_BASE;
319                 info.high_limit = TASK_SIZE;
320                 addr = vm_unmapped_area(&info);
321         }
322
323         return addr;
324 }
325
326 unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
327                 unsigned long len, unsigned long pgoff, unsigned long flags)
328 {
329         struct hstate *h = hstate_file(file);
330         struct mm_struct *mm = current->mm;
331         struct vm_area_struct *vma;
332         int rc;
333
334         if (len & ~huge_page_mask(h))
335                 return -EINVAL;
336         if (len > TASK_SIZE - mmap_min_addr)
337                 return -ENOMEM;
338
339         if (flags & MAP_FIXED) {
340                 if (prepare_hugepage_range(file, addr, len))
341                         return -EINVAL;
342                 goto check_asce_limit;
343         }
344
345         if (addr) {
346                 addr = ALIGN(addr, huge_page_size(h));
347                 vma = find_vma(mm, addr);
348                 if (TASK_SIZE - len >= addr && addr >= mmap_min_addr &&
349                     (!vma || addr + len <= vm_start_gap(vma)))
350                         goto check_asce_limit;
351         }
352
353         if (mm->get_unmapped_area == arch_get_unmapped_area)
354                 addr = hugetlb_get_unmapped_area_bottomup(file, addr, len,
355                                 pgoff, flags);
356         else
357                 addr = hugetlb_get_unmapped_area_topdown(file, addr, len,
358                                 pgoff, flags);
359         if (addr & ~PAGE_MASK)
360                 return addr;
361
362 check_asce_limit:
363         if (addr + len > current->mm->context.asce_limit &&
364             addr + len <= TASK_SIZE) {
365                 rc = crst_table_upgrade(mm, addr + len);
366                 if (rc)
367                         return (unsigned long) rc;
368         }
369         return addr;
370 }