1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* |
3 | * Page table allocation functions |
4 | * |
5 | * Copyright IBM Corp. 2016 |
6 | * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com> |
7 | */ |
8 | |
9 | #include <linux/sysctl.h> |
10 | #include <linux/slab.h> |
11 | #include <linux/mm.h> |
12 | #include <asm/mmu_context.h> |
13 | #include <asm/page-states.h> |
14 | #include <asm/pgalloc.h> |
15 | #include <asm/gmap.h> |
16 | #include <asm/tlb.h> |
17 | #include <asm/tlbflush.h> |
18 | |
19 | #ifdef CONFIG_PGSTE |
20 | |
21 | int page_table_allocate_pgste = 0; |
22 | EXPORT_SYMBOL(page_table_allocate_pgste); |
23 | |
24 | static struct ctl_table page_table_sysctl[] = { |
25 | { |
26 | .procname = "allocate_pgste" , |
27 | .data = &page_table_allocate_pgste, |
28 | .maxlen = sizeof(int), |
29 | .mode = S_IRUGO | S_IWUSR, |
30 | .proc_handler = proc_dointvec_minmax, |
31 | .extra1 = SYSCTL_ZERO, |
32 | .extra2 = SYSCTL_ONE, |
33 | }, |
34 | }; |
35 | |
36 | static int __init page_table_register_sysctl(void) |
37 | { |
38 | return register_sysctl("vm" , page_table_sysctl) ? 0 : -ENOMEM; |
39 | } |
40 | __initcall(page_table_register_sysctl); |
41 | |
42 | #endif /* CONFIG_PGSTE */ |
43 | |
44 | unsigned long *crst_table_alloc(struct mm_struct *mm) |
45 | { |
46 | struct ptdesc *ptdesc = pagetable_alloc(GFP_KERNEL, order: CRST_ALLOC_ORDER); |
47 | unsigned long *table; |
48 | |
49 | if (!ptdesc) |
50 | return NULL; |
51 | table = ptdesc_to_virt(pt: ptdesc); |
52 | __arch_set_page_dat(table, 1UL << CRST_ALLOC_ORDER); |
53 | return table; |
54 | } |
55 | |
56 | void crst_table_free(struct mm_struct *mm, unsigned long *table) |
57 | { |
58 | pagetable_free(pt: virt_to_ptdesc(x: table)); |
59 | } |
60 | |
61 | static void __crst_table_upgrade(void *arg) |
62 | { |
63 | struct mm_struct *mm = arg; |
64 | |
65 | /* change all active ASCEs to avoid the creation of new TLBs */ |
66 | if (current->active_mm == mm) { |
67 | S390_lowcore.user_asce.val = mm->context.asce; |
68 | local_ctl_load(7, &S390_lowcore.user_asce); |
69 | } |
70 | __tlb_flush_local(); |
71 | } |
72 | |
73 | int crst_table_upgrade(struct mm_struct *mm, unsigned long end) |
74 | { |
75 | unsigned long *pgd = NULL, *p4d = NULL, *__pgd; |
76 | unsigned long asce_limit = mm->context.asce_limit; |
77 | |
78 | /* upgrade should only happen from 3 to 4, 3 to 5, or 4 to 5 levels */ |
79 | VM_BUG_ON(asce_limit < _REGION2_SIZE); |
80 | |
81 | if (end <= asce_limit) |
82 | return 0; |
83 | |
84 | if (asce_limit == _REGION2_SIZE) { |
85 | p4d = crst_table_alloc(mm); |
86 | if (unlikely(!p4d)) |
87 | goto err_p4d; |
88 | crst_table_init(p4d, _REGION2_ENTRY_EMPTY); |
89 | } |
90 | if (end > _REGION1_SIZE) { |
91 | pgd = crst_table_alloc(mm); |
92 | if (unlikely(!pgd)) |
93 | goto err_pgd; |
94 | crst_table_init(pgd, _REGION1_ENTRY_EMPTY); |
95 | } |
96 | |
97 | spin_lock_bh(lock: &mm->page_table_lock); |
98 | |
99 | /* |
100 | * This routine gets called with mmap_lock lock held and there is |
101 | * no reason to optimize for the case of otherwise. However, if |
102 | * that would ever change, the below check will let us know. |
103 | */ |
104 | VM_BUG_ON(asce_limit != mm->context.asce_limit); |
105 | |
106 | if (p4d) { |
107 | __pgd = (unsigned long *) mm->pgd; |
108 | p4d_populate(mm, p4d: (p4d_t *) p4d, pud: (pud_t *) __pgd); |
109 | mm->pgd = (pgd_t *) p4d; |
110 | mm->context.asce_limit = _REGION1_SIZE; |
111 | mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH | |
112 | _ASCE_USER_BITS | _ASCE_TYPE_REGION2; |
113 | mm_inc_nr_puds(mm); |
114 | } |
115 | if (pgd) { |
116 | __pgd = (unsigned long *) mm->pgd; |
117 | pgd_populate(mm, pgd: (pgd_t *) pgd, p4d: (p4d_t *) __pgd); |
118 | mm->pgd = (pgd_t *) pgd; |
119 | mm->context.asce_limit = TASK_SIZE_MAX; |
120 | mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH | |
121 | _ASCE_USER_BITS | _ASCE_TYPE_REGION1; |
122 | } |
123 | |
124 | spin_unlock_bh(lock: &mm->page_table_lock); |
125 | |
126 | on_each_cpu(func: __crst_table_upgrade, info: mm, wait: 0); |
127 | |
128 | return 0; |
129 | |
130 | err_pgd: |
131 | crst_table_free(mm, table: p4d); |
132 | err_p4d: |
133 | return -ENOMEM; |
134 | } |
135 | |
136 | #ifdef CONFIG_PGSTE |
137 | |
138 | struct ptdesc *page_table_alloc_pgste(struct mm_struct *mm) |
139 | { |
140 | struct ptdesc *ptdesc; |
141 | u64 *table; |
142 | |
143 | ptdesc = pagetable_alloc(GFP_KERNEL, 0); |
144 | if (ptdesc) { |
145 | table = (u64 *)ptdesc_to_virt(ptdesc); |
146 | __arch_set_page_dat(table, 1); |
147 | memset64(table, _PAGE_INVALID, PTRS_PER_PTE); |
148 | memset64(table + PTRS_PER_PTE, 0, PTRS_PER_PTE); |
149 | } |
150 | return ptdesc; |
151 | } |
152 | |
153 | void page_table_free_pgste(struct ptdesc *ptdesc) |
154 | { |
155 | pagetable_free(ptdesc); |
156 | } |
157 | |
158 | #endif /* CONFIG_PGSTE */ |
159 | |
160 | unsigned long *page_table_alloc(struct mm_struct *mm) |
161 | { |
162 | struct ptdesc *ptdesc; |
163 | unsigned long *table; |
164 | |
165 | ptdesc = pagetable_alloc(GFP_KERNEL, order: 0); |
166 | if (!ptdesc) |
167 | return NULL; |
168 | if (!pagetable_pte_ctor(ptdesc)) { |
169 | pagetable_free(pt: ptdesc); |
170 | return NULL; |
171 | } |
172 | table = ptdesc_to_virt(pt: ptdesc); |
173 | __arch_set_page_dat(table, 1); |
174 | /* pt_list is used by gmap only */ |
175 | INIT_LIST_HEAD(list: &ptdesc->pt_list); |
176 | memset64(s: (u64 *)table, v: _PAGE_INVALID, PTRS_PER_PTE); |
177 | memset64(s: (u64 *)table + PTRS_PER_PTE, v: 0, PTRS_PER_PTE); |
178 | return table; |
179 | } |
180 | |
181 | static void pagetable_pte_dtor_free(struct ptdesc *ptdesc) |
182 | { |
183 | pagetable_pte_dtor(ptdesc); |
184 | pagetable_free(pt: ptdesc); |
185 | } |
186 | |
187 | void page_table_free(struct mm_struct *mm, unsigned long *table) |
188 | { |
189 | struct ptdesc *ptdesc = virt_to_ptdesc(x: table); |
190 | |
191 | pagetable_pte_dtor_free(ptdesc); |
192 | } |
193 | |
194 | void __tlb_remove_table(void *table) |
195 | { |
196 | struct ptdesc *ptdesc = virt_to_ptdesc(x: table); |
197 | struct page *page = ptdesc_page(ptdesc); |
198 | |
199 | if (compound_order(page) == CRST_ALLOC_ORDER) { |
200 | /* pmd, pud, or p4d */ |
201 | pagetable_free(pt: ptdesc); |
202 | return; |
203 | } |
204 | pagetable_pte_dtor_free(ptdesc); |
205 | } |
206 | |
207 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE |
208 | static void pte_free_now(struct rcu_head *head) |
209 | { |
210 | struct ptdesc *ptdesc = container_of(head, struct ptdesc, pt_rcu_head); |
211 | |
212 | pagetable_pte_dtor_free(ptdesc); |
213 | } |
214 | |
215 | void pte_free_defer(struct mm_struct *mm, pgtable_t pgtable) |
216 | { |
217 | struct ptdesc *ptdesc = virt_to_ptdesc(x: pgtable); |
218 | |
219 | call_rcu(head: &ptdesc->pt_rcu_head, func: pte_free_now); |
220 | /* |
221 | * THPs are not allowed for KVM guests. Warn if pgste ever reaches here. |
222 | * Turn to the generic pte_free_defer() version once gmap is removed. |
223 | */ |
224 | WARN_ON_ONCE(mm_has_pgste(mm)); |
225 | } |
226 | #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ |
227 | |
228 | /* |
229 | * Base infrastructure required to generate basic asces, region, segment, |
230 | * and page tables that do not make use of enhanced features like EDAT1. |
231 | */ |
232 | |
233 | static struct kmem_cache *base_pgt_cache; |
234 | |
235 | static unsigned long *base_pgt_alloc(void) |
236 | { |
237 | unsigned long *table; |
238 | |
239 | table = kmem_cache_alloc(cachep: base_pgt_cache, GFP_KERNEL); |
240 | if (table) |
241 | memset64(s: (u64 *)table, v: _PAGE_INVALID, PTRS_PER_PTE); |
242 | return table; |
243 | } |
244 | |
245 | static void base_pgt_free(unsigned long *table) |
246 | { |
247 | kmem_cache_free(s: base_pgt_cache, objp: table); |
248 | } |
249 | |
250 | static unsigned long *base_crst_alloc(unsigned long val) |
251 | { |
252 | unsigned long *table; |
253 | struct ptdesc *ptdesc; |
254 | |
255 | ptdesc = pagetable_alloc(GFP_KERNEL, order: CRST_ALLOC_ORDER); |
256 | if (!ptdesc) |
257 | return NULL; |
258 | table = ptdesc_address(pt: ptdesc); |
259 | crst_table_init(table, val); |
260 | return table; |
261 | } |
262 | |
263 | static void base_crst_free(unsigned long *table) |
264 | { |
265 | pagetable_free(pt: virt_to_ptdesc(x: table)); |
266 | } |
267 | |
268 | #define BASE_ADDR_END_FUNC(NAME, SIZE) \ |
269 | static inline unsigned long base_##NAME##_addr_end(unsigned long addr, \ |
270 | unsigned long end) \ |
271 | { \ |
272 | unsigned long next = (addr + (SIZE)) & ~((SIZE) - 1); \ |
273 | \ |
274 | return (next - 1) < (end - 1) ? next : end; \ |
275 | } |
276 | |
277 | BASE_ADDR_END_FUNC(page, _PAGE_SIZE) |
278 | BASE_ADDR_END_FUNC(segment, _SEGMENT_SIZE) |
279 | BASE_ADDR_END_FUNC(region3, _REGION3_SIZE) |
280 | BASE_ADDR_END_FUNC(region2, _REGION2_SIZE) |
281 | BASE_ADDR_END_FUNC(region1, _REGION1_SIZE) |
282 | |
283 | static inline unsigned long base_lra(unsigned long address) |
284 | { |
285 | unsigned long real; |
286 | |
287 | asm volatile( |
288 | " lra %0,0(%1)\n" |
289 | : "=d" (real) : "a" (address) : "cc" ); |
290 | return real; |
291 | } |
292 | |
293 | static int base_page_walk(unsigned long *origin, unsigned long addr, |
294 | unsigned long end, int alloc) |
295 | { |
296 | unsigned long *pte, next; |
297 | |
298 | if (!alloc) |
299 | return 0; |
300 | pte = origin; |
301 | pte += (addr & _PAGE_INDEX) >> _PAGE_SHIFT; |
302 | do { |
303 | next = base_page_addr_end(addr, end); |
304 | *pte = base_lra(address: addr); |
305 | } while (pte++, addr = next, addr < end); |
306 | return 0; |
307 | } |
308 | |
309 | static int base_segment_walk(unsigned long *origin, unsigned long addr, |
310 | unsigned long end, int alloc) |
311 | { |
312 | unsigned long *ste, next, *table; |
313 | int rc; |
314 | |
315 | ste = origin; |
316 | ste += (addr & _SEGMENT_INDEX) >> _SEGMENT_SHIFT; |
317 | do { |
318 | next = base_segment_addr_end(addr, end); |
319 | if (*ste & _SEGMENT_ENTRY_INVALID) { |
320 | if (!alloc) |
321 | continue; |
322 | table = base_pgt_alloc(); |
323 | if (!table) |
324 | return -ENOMEM; |
325 | *ste = __pa(table) | _SEGMENT_ENTRY; |
326 | } |
327 | table = __va(*ste & _SEGMENT_ENTRY_ORIGIN); |
328 | rc = base_page_walk(origin: table, addr, end: next, alloc); |
329 | if (rc) |
330 | return rc; |
331 | if (!alloc) |
332 | base_pgt_free(table); |
333 | cond_resched(); |
334 | } while (ste++, addr = next, addr < end); |
335 | return 0; |
336 | } |
337 | |
338 | static int base_region3_walk(unsigned long *origin, unsigned long addr, |
339 | unsigned long end, int alloc) |
340 | { |
341 | unsigned long *rtte, next, *table; |
342 | int rc; |
343 | |
344 | rtte = origin; |
345 | rtte += (addr & _REGION3_INDEX) >> _REGION3_SHIFT; |
346 | do { |
347 | next = base_region3_addr_end(addr, end); |
348 | if (*rtte & _REGION_ENTRY_INVALID) { |
349 | if (!alloc) |
350 | continue; |
351 | table = base_crst_alloc(_SEGMENT_ENTRY_EMPTY); |
352 | if (!table) |
353 | return -ENOMEM; |
354 | *rtte = __pa(table) | _REGION3_ENTRY; |
355 | } |
356 | table = __va(*rtte & _REGION_ENTRY_ORIGIN); |
357 | rc = base_segment_walk(origin: table, addr, end: next, alloc); |
358 | if (rc) |
359 | return rc; |
360 | if (!alloc) |
361 | base_crst_free(table); |
362 | } while (rtte++, addr = next, addr < end); |
363 | return 0; |
364 | } |
365 | |
366 | static int base_region2_walk(unsigned long *origin, unsigned long addr, |
367 | unsigned long end, int alloc) |
368 | { |
369 | unsigned long *rste, next, *table; |
370 | int rc; |
371 | |
372 | rste = origin; |
373 | rste += (addr & _REGION2_INDEX) >> _REGION2_SHIFT; |
374 | do { |
375 | next = base_region2_addr_end(addr, end); |
376 | if (*rste & _REGION_ENTRY_INVALID) { |
377 | if (!alloc) |
378 | continue; |
379 | table = base_crst_alloc(_REGION3_ENTRY_EMPTY); |
380 | if (!table) |
381 | return -ENOMEM; |
382 | *rste = __pa(table) | _REGION2_ENTRY; |
383 | } |
384 | table = __va(*rste & _REGION_ENTRY_ORIGIN); |
385 | rc = base_region3_walk(origin: table, addr, end: next, alloc); |
386 | if (rc) |
387 | return rc; |
388 | if (!alloc) |
389 | base_crst_free(table); |
390 | } while (rste++, addr = next, addr < end); |
391 | return 0; |
392 | } |
393 | |
394 | static int base_region1_walk(unsigned long *origin, unsigned long addr, |
395 | unsigned long end, int alloc) |
396 | { |
397 | unsigned long *rfte, next, *table; |
398 | int rc; |
399 | |
400 | rfte = origin; |
401 | rfte += (addr & _REGION1_INDEX) >> _REGION1_SHIFT; |
402 | do { |
403 | next = base_region1_addr_end(addr, end); |
404 | if (*rfte & _REGION_ENTRY_INVALID) { |
405 | if (!alloc) |
406 | continue; |
407 | table = base_crst_alloc(_REGION2_ENTRY_EMPTY); |
408 | if (!table) |
409 | return -ENOMEM; |
410 | *rfte = __pa(table) | _REGION1_ENTRY; |
411 | } |
412 | table = __va(*rfte & _REGION_ENTRY_ORIGIN); |
413 | rc = base_region2_walk(origin: table, addr, end: next, alloc); |
414 | if (rc) |
415 | return rc; |
416 | if (!alloc) |
417 | base_crst_free(table); |
418 | } while (rfte++, addr = next, addr < end); |
419 | return 0; |
420 | } |
421 | |
422 | /** |
423 | * base_asce_free - free asce and tables returned from base_asce_alloc() |
424 | * @asce: asce to be freed |
425 | * |
426 | * Frees all region, segment, and page tables that were allocated with a |
427 | * corresponding base_asce_alloc() call. |
428 | */ |
429 | void base_asce_free(unsigned long asce) |
430 | { |
431 | unsigned long *table = __va(asce & _ASCE_ORIGIN); |
432 | |
433 | if (!asce) |
434 | return; |
435 | switch (asce & _ASCE_TYPE_MASK) { |
436 | case _ASCE_TYPE_SEGMENT: |
437 | base_segment_walk(table, 0, _REGION3_SIZE, 0); |
438 | break; |
439 | case _ASCE_TYPE_REGION3: |
440 | base_region3_walk(table, 0, _REGION2_SIZE, 0); |
441 | break; |
442 | case _ASCE_TYPE_REGION2: |
443 | base_region2_walk(table, 0, _REGION1_SIZE, 0); |
444 | break; |
445 | case _ASCE_TYPE_REGION1: |
446 | base_region1_walk(origin: table, addr: 0, TASK_SIZE_MAX, alloc: 0); |
447 | break; |
448 | } |
449 | base_crst_free(table); |
450 | } |
451 | |
452 | static int base_pgt_cache_init(void) |
453 | { |
454 | static DEFINE_MUTEX(base_pgt_cache_mutex); |
455 | unsigned long sz = _PAGE_TABLE_SIZE; |
456 | |
457 | if (base_pgt_cache) |
458 | return 0; |
459 | mutex_lock(&base_pgt_cache_mutex); |
460 | if (!base_pgt_cache) |
461 | base_pgt_cache = kmem_cache_create(name: "base_pgt" , size: sz, align: sz, flags: 0, NULL); |
462 | mutex_unlock(lock: &base_pgt_cache_mutex); |
463 | return base_pgt_cache ? 0 : -ENOMEM; |
464 | } |
465 | |
466 | /** |
467 | * base_asce_alloc - create kernel mapping without enhanced DAT features |
468 | * @addr: virtual start address of kernel mapping |
469 | * @num_pages: number of consecutive pages |
470 | * |
471 | * Generate an asce, including all required region, segment and page tables, |
472 | * that can be used to access the virtual kernel mapping. The difference is |
473 | * that the returned asce does not make use of any enhanced DAT features like |
474 | * e.g. large pages. This is required for some I/O functions that pass an |
475 | * asce, like e.g. some service call requests. |
476 | * |
477 | * Note: the returned asce may NEVER be attached to any cpu. It may only be |
478 | * used for I/O requests. tlb entries that might result because the |
479 | * asce was attached to a cpu won't be cleared. |
480 | */ |
481 | unsigned long base_asce_alloc(unsigned long addr, unsigned long num_pages) |
482 | { |
483 | unsigned long asce, *table, end; |
484 | int rc; |
485 | |
486 | if (base_pgt_cache_init()) |
487 | return 0; |
488 | end = addr + num_pages * PAGE_SIZE; |
489 | if (end <= _REGION3_SIZE) { |
490 | table = base_crst_alloc(_SEGMENT_ENTRY_EMPTY); |
491 | if (!table) |
492 | return 0; |
493 | rc = base_segment_walk(origin: table, addr, end, alloc: 1); |
494 | asce = __pa(table) | _ASCE_TYPE_SEGMENT | _ASCE_TABLE_LENGTH; |
495 | } else if (end <= _REGION2_SIZE) { |
496 | table = base_crst_alloc(_REGION3_ENTRY_EMPTY); |
497 | if (!table) |
498 | return 0; |
499 | rc = base_region3_walk(origin: table, addr, end, alloc: 1); |
500 | asce = __pa(table) | _ASCE_TYPE_REGION3 | _ASCE_TABLE_LENGTH; |
501 | } else if (end <= _REGION1_SIZE) { |
502 | table = base_crst_alloc(_REGION2_ENTRY_EMPTY); |
503 | if (!table) |
504 | return 0; |
505 | rc = base_region2_walk(origin: table, addr, end, alloc: 1); |
506 | asce = __pa(table) | _ASCE_TYPE_REGION2 | _ASCE_TABLE_LENGTH; |
507 | } else { |
508 | table = base_crst_alloc(_REGION1_ENTRY_EMPTY); |
509 | if (!table) |
510 | return 0; |
511 | rc = base_region1_walk(origin: table, addr, end, alloc: 1); |
512 | asce = __pa(table) | _ASCE_TYPE_REGION1 | _ASCE_TABLE_LENGTH; |
513 | } |
514 | if (rc) { |
515 | base_asce_free(asce); |
516 | asce = 0; |
517 | } |
518 | return asce; |
519 | } |
520 | |