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nfsd: don't fail unchecked creates of non-special files
[zen-stable.git] / arch / s390 / mm / pgtable.c
blob6dc115b96a13afdb7d22799884e8a95d891f2dbd
1 /*
2 * Copyright IBM Corp. 2007,2011
3 * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
4 */
5
6 #include <linux/sched.h>
7 #include <linux/kernel.h>
8 #include <linux/errno.h>
9 #include <linux/gfp.h>
10 #include <linux/mm.h>
11 #include <linux/swap.h>
12 #include <linux/smp.h>
13 #include <linux/highmem.h>
14 #include <linux/pagemap.h>
15 #include <linux/spinlock.h>
16 #include <linux/module.h>
17 #include <linux/quicklist.h>
18 #include <linux/rcupdate.h>
19 #include <linux/slab.h>
20
21 #include <asm/system.h>
22 #include <asm/pgtable.h>
23 #include <asm/pgalloc.h>
24 #include <asm/tlb.h>
25 #include <asm/tlbflush.h>
26 #include <asm/mmu_context.h>
27
28 #ifndef CONFIG_64BIT
29 #define ALLOC_ORDER 1
30 #define FRAG_MASK 0x0f
31 #else
32 #define ALLOC_ORDER 2
33 #define FRAG_MASK 0x03
34 #endif
35
36
37 unsigned long *crst_table_alloc(struct mm_struct *mm)
38 {
39 struct page *page = alloc_pages(GFP_KERNEL, ALLOC_ORDER);
40
41 if (!page)
42 return NULL;
43 return (unsigned long *) page_to_phys(page);
44 }
45
46 void crst_table_free(struct mm_struct *mm, unsigned long *table)
47 {
48 free_pages((unsigned long) table, ALLOC_ORDER);
49 }
50
51 #ifdef CONFIG_64BIT
52 int crst_table_upgrade(struct mm_struct *mm, unsigned long limit)
53 {
54 unsigned long *table, *pgd;
55 unsigned long entry;
56
57 BUG_ON(limit > (1UL << 53));
58 repeat:
59 table = crst_table_alloc(mm);
60 if (!table)
61 return -ENOMEM;
62 spin_lock_bh(&mm->page_table_lock);
63 if (mm->context.asce_limit < limit) {
64 pgd = (unsigned long *) mm->pgd;
65 if (mm->context.asce_limit <= (1UL << 31)) {
66 entry = _REGION3_ENTRY_EMPTY;
67 mm->context.asce_limit = 1UL << 42;
68 mm->context.asce_bits = _ASCE_TABLE_LENGTH |
69 _ASCE_USER_BITS |
70 _ASCE_TYPE_REGION3;
71 } else {
72 entry = _REGION2_ENTRY_EMPTY;
73 mm->context.asce_limit = 1UL << 53;
74 mm->context.asce_bits = _ASCE_TABLE_LENGTH |
75 _ASCE_USER_BITS |
76 _ASCE_TYPE_REGION2;
77 }
78 crst_table_init(table, entry);
79 pgd_populate(mm, (pgd_t *) table, (pud_t *) pgd);
80 mm->pgd = (pgd_t *) table;
81 mm->task_size = mm->context.asce_limit;
82 table = NULL;
83 }
84 spin_unlock_bh(&mm->page_table_lock);
85 if (table)
86 crst_table_free(mm, table);
87 if (mm->context.asce_limit < limit)
88 goto repeat;
89 update_mm(mm, current);
90 return 0;
91 }
92
93 void crst_table_downgrade(struct mm_struct *mm, unsigned long limit)
94 {
95 pgd_t *pgd;
96
97 if (mm->context.asce_limit <= limit)
98 return;
99 __tlb_flush_mm(mm);
100 while (mm->context.asce_limit > limit) {
101 pgd = mm->pgd;
102 switch (pgd_val(*pgd) & _REGION_ENTRY_TYPE_MASK) {
103 case _REGION_ENTRY_TYPE_R2:
104 mm->context.asce_limit = 1UL << 42;
105 mm->context.asce_bits = _ASCE_TABLE_LENGTH |
106 _ASCE_USER_BITS |
107 _ASCE_TYPE_REGION3;
108 break;
109 case _REGION_ENTRY_TYPE_R3:
110 mm->context.asce_limit = 1UL << 31;
111 mm->context.asce_bits = _ASCE_TABLE_LENGTH |
112 _ASCE_USER_BITS |
113 _ASCE_TYPE_SEGMENT;
114 break;
115 default:
116 BUG();
117 }
118 mm->pgd = (pgd_t *) (pgd_val(*pgd) & _REGION_ENTRY_ORIGIN);
119 mm->task_size = mm->context.asce_limit;
120 crst_table_free(mm, (unsigned long *) pgd);
121 }
122 update_mm(mm, current);
123 }
124 #endif
125
126 #ifdef CONFIG_PGSTE
127
128 /**
129 * gmap_alloc - allocate a guest address space
130 * @mm: pointer to the parent mm_struct
131 *
132 * Returns a guest address space structure.
133 */
134 struct gmap *gmap_alloc(struct mm_struct *mm)
135 {
136 struct gmap *gmap;
137 struct page *page;
138 unsigned long *table;
139
140 gmap = kzalloc(sizeof(struct gmap), GFP_KERNEL);
141 if (!gmap)
142 goto out;
143 INIT_LIST_HEAD(&gmap->crst_list);
144 gmap->mm = mm;
145 page = alloc_pages(GFP_KERNEL, ALLOC_ORDER);
146 if (!page)
147 goto out_free;
148 list_add(&page->lru, &gmap->crst_list);
149 table = (unsigned long *) page_to_phys(page);
150 crst_table_init(table, _REGION1_ENTRY_EMPTY);
151 gmap->table = table;
152 gmap->asce = _ASCE_TYPE_REGION1 | _ASCE_TABLE_LENGTH |
153 _ASCE_USER_BITS | __pa(table);
154 list_add(&gmap->list, &mm->context.gmap_list);
155 return gmap;
156
157 out_free:
158 kfree(gmap);
159 out:
160 return NULL;
161 }
162 EXPORT_SYMBOL_GPL(gmap_alloc);
163
164 static int gmap_unlink_segment(struct gmap *gmap, unsigned long *table)
165 {
166 struct gmap_pgtable *mp;
167 struct gmap_rmap *rmap;
168 struct page *page;
169
170 if (*table & _SEGMENT_ENTRY_INV)
171 return 0;
172 page = pfn_to_page(*table >> PAGE_SHIFT);
173 mp = (struct gmap_pgtable *) page->index;
174 list_for_each_entry(rmap, &mp->mapper, list) {
175 if (rmap->entry != table)
176 continue;
177 list_del(&rmap->list);
178 kfree(rmap);
179 break;
180 }
181 *table = _SEGMENT_ENTRY_INV | _SEGMENT_ENTRY_RO | mp->vmaddr;
182 return 1;
183 }
184
185 static void gmap_flush_tlb(struct gmap *gmap)
186 {
187 if (MACHINE_HAS_IDTE)
188 __tlb_flush_idte((unsigned long) gmap->table |
189 _ASCE_TYPE_REGION1);
190 else
191 __tlb_flush_global();
192 }
193
194 /**
195 * gmap_free - free a guest address space
196 * @gmap: pointer to the guest address space structure
197 */
198 void gmap_free(struct gmap *gmap)
199 {
200 struct page *page, *next;
201 unsigned long *table;
202 int i;
203
204
205 /* Flush tlb. */
206 if (MACHINE_HAS_IDTE)
207 __tlb_flush_idte((unsigned long) gmap->table |
208 _ASCE_TYPE_REGION1);
209 else
210 __tlb_flush_global();
211
212 /* Free all segment & region tables. */
213 down_read(&gmap->mm->mmap_sem);
214 spin_lock(&gmap->mm->page_table_lock);
215 list_for_each_entry_safe(page, next, &gmap->crst_list, lru) {
216 table = (unsigned long *) page_to_phys(page);
217 if ((*table & _REGION_ENTRY_TYPE_MASK) == 0)
218 /* Remove gmap rmap structures for segment table. */
219 for (i = 0; i < PTRS_PER_PMD; i++, table++)
220 gmap_unlink_segment(gmap, table);
221 __free_pages(page, ALLOC_ORDER);
222 }
223 spin_unlock(&gmap->mm->page_table_lock);
224 up_read(&gmap->mm->mmap_sem);
225 list_del(&gmap->list);
226 kfree(gmap);
227 }
228 EXPORT_SYMBOL_GPL(gmap_free);
229
230 /**
231 * gmap_enable - switch primary space to the guest address space
232 * @gmap: pointer to the guest address space structure
233 */
234 void gmap_enable(struct gmap *gmap)
235 {
236 S390_lowcore.gmap = (unsigned long) gmap;
237 }
238 EXPORT_SYMBOL_GPL(gmap_enable);
239
240 /**
241 * gmap_disable - switch back to the standard primary address space
242 * @gmap: pointer to the guest address space structure
243 */
244 void gmap_disable(struct gmap *gmap)
245 {
246 S390_lowcore.gmap = 0UL;
247 }
248 EXPORT_SYMBOL_GPL(gmap_disable);
249
250 /*
251 * gmap_alloc_table is assumed to be called with mmap_sem held
252 */
253 static int gmap_alloc_table(struct gmap *gmap,
254 unsigned long *table, unsigned long init)
255 {
256 struct page *page;
257 unsigned long *new;
258
259 /* since we dont free the gmap table until gmap_free we can unlock */
260 spin_unlock(&gmap->mm->page_table_lock);
261 page = alloc_pages(GFP_KERNEL, ALLOC_ORDER);
262 spin_lock(&gmap->mm->page_table_lock);
263 if (!page)
264 return -ENOMEM;
265 new = (unsigned long *) page_to_phys(page);
266 crst_table_init(new, init);
267 if (*table & _REGION_ENTRY_INV) {
268 list_add(&page->lru, &gmap->crst_list);
269 *table = (unsigned long) new | _REGION_ENTRY_LENGTH |
270 (*table & _REGION_ENTRY_TYPE_MASK);
271 } else
272 __free_pages(page, ALLOC_ORDER);
273 return 0;
274 }
275
276 /**
277 * gmap_unmap_segment - unmap segment from the guest address space
278 * @gmap: pointer to the guest address space structure
279 * @addr: address in the guest address space
280 * @len: length of the memory area to unmap
281 *
282 * Returns 0 if the unmap succeded, -EINVAL if not.
283 */
284 int gmap_unmap_segment(struct gmap *gmap, unsigned long to, unsigned long len)
285 {
286 unsigned long *table;
287 unsigned long off;
288 int flush;
289
290 if ((to | len) & (PMD_SIZE - 1))
291 return -EINVAL;
292 if (len == 0 || to + len < to)
293 return -EINVAL;
294
295 flush = 0;
296 down_read(&gmap->mm->mmap_sem);
297 spin_lock(&gmap->mm->page_table_lock);
298 for (off = 0; off < len; off += PMD_SIZE) {
299 /* Walk the guest addr space page table */
300 table = gmap->table + (((to + off) >> 53) & 0x7ff);
301 if (*table & _REGION_ENTRY_INV)
302 goto out;
303 table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
304 table = table + (((to + off) >> 42) & 0x7ff);
305 if (*table & _REGION_ENTRY_INV)
306 goto out;
307 table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
308 table = table + (((to + off) >> 31) & 0x7ff);
309 if (*table & _REGION_ENTRY_INV)
310 goto out;
311 table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
312 table = table + (((to + off) >> 20) & 0x7ff);
313
314 /* Clear segment table entry in guest address space. */
315 flush |= gmap_unlink_segment(gmap, table);
316 *table = _SEGMENT_ENTRY_INV;
317 }
318 out:
319 spin_unlock(&gmap->mm->page_table_lock);
320 up_read(&gmap->mm->mmap_sem);
321 if (flush)
322 gmap_flush_tlb(gmap);
323 return 0;
324 }
325 EXPORT_SYMBOL_GPL(gmap_unmap_segment);
326
327 /**
328 * gmap_mmap_segment - map a segment to the guest address space
329 * @gmap: pointer to the guest address space structure
330 * @from: source address in the parent address space
331 * @to: target address in the guest address space
332 *
333 * Returns 0 if the mmap succeded, -EINVAL or -ENOMEM if not.
334 */
335 int gmap_map_segment(struct gmap *gmap, unsigned long from,
336 unsigned long to, unsigned long len)
337 {
338 unsigned long *table;
339 unsigned long off;
340 int flush;
341
342 if ((from | to | len) & (PMD_SIZE - 1))
343 return -EINVAL;
344 if (len == 0 || from + len > PGDIR_SIZE ||
345 from + len < from || to + len < to)
346 return -EINVAL;
347
348 flush = 0;
349 down_read(&gmap->mm->mmap_sem);
350 spin_lock(&gmap->mm->page_table_lock);
351 for (off = 0; off < len; off += PMD_SIZE) {
352 /* Walk the gmap address space page table */
353 table = gmap->table + (((to + off) >> 53) & 0x7ff);
354 if ((*table & _REGION_ENTRY_INV) &&
355 gmap_alloc_table(gmap, table, _REGION2_ENTRY_EMPTY))
356 goto out_unmap;
357 table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
358 table = table + (((to + off) >> 42) & 0x7ff);
359 if ((*table & _REGION_ENTRY_INV) &&
360 gmap_alloc_table(gmap, table, _REGION3_ENTRY_EMPTY))
361 goto out_unmap;
362 table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
363 table = table + (((to + off) >> 31) & 0x7ff);
364 if ((*table & _REGION_ENTRY_INV) &&
365 gmap_alloc_table(gmap, table, _SEGMENT_ENTRY_EMPTY))
366 goto out_unmap;
367 table = (unsigned long *) (*table & _REGION_ENTRY_ORIGIN);
368 table = table + (((to + off) >> 20) & 0x7ff);
369
370 /* Store 'from' address in an invalid segment table entry. */
371 flush |= gmap_unlink_segment(gmap, table);
372 *table = _SEGMENT_ENTRY_INV | _SEGMENT_ENTRY_RO | (from + off);
373 }
374 spin_unlock(&gmap->mm->page_table_lock);
375 up_read(&gmap->mm->mmap_sem);
376 if (flush)
377 gmap_flush_tlb(gmap);
378 return 0;
379
380 out_unmap:
381 spin_unlock(&gmap->mm->page_table_lock);
382 up_read(&gmap->mm->mmap_sem);
383 gmap_unmap_segment(gmap, to, len);
384 return -ENOMEM;
385 }
386 EXPORT_SYMBOL_GPL(gmap_map_segment);
387
388 /*
389 * this function is assumed to be called with mmap_sem held
390 */
391 unsigned long __gmap_fault(unsigned long address, struct gmap *gmap)
392 {
393 unsigned long *table, vmaddr, segment;
394 struct mm_struct *mm;
395 struct gmap_pgtable *mp;
396 struct gmap_rmap *rmap;
397 struct vm_area_struct *vma;
398 struct page *page;
399 pgd_t *pgd;
400 pud_t *pud;
401 pmd_t *pmd;
402
403 current->thread.gmap_addr = address;
404 mm = gmap->mm;
405 /* Walk the gmap address space page table */
406 table = gmap->table + ((address >> 53) & 0x7ff);
407 if (unlikely(*table & _REGION_ENTRY_INV))
408 return -EFAULT;
409 table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
410 table = table + ((address >> 42) & 0x7ff);
411 if (unlikely(*table & _REGION_ENTRY_INV))
412 return -EFAULT;
413 table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
414 table = table + ((address >> 31) & 0x7ff);
415 if (unlikely(*table & _REGION_ENTRY_INV))
416 return -EFAULT;
417 table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
418 table = table + ((address >> 20) & 0x7ff);
419
420 /* Convert the gmap address to an mm address. */
421 segment = *table;
422 if (likely(!(segment & _SEGMENT_ENTRY_INV))) {
423 page = pfn_to_page(segment >> PAGE_SHIFT);
424 mp = (struct gmap_pgtable *) page->index;
425 return mp->vmaddr | (address & ~PMD_MASK);
426 } else if (segment & _SEGMENT_ENTRY_RO) {
427 vmaddr = segment & _SEGMENT_ENTRY_ORIGIN;
428 vma = find_vma(mm, vmaddr);
429 if (!vma || vma->vm_start > vmaddr)
430 return -EFAULT;
431
432 /* Walk the parent mm page table */
433 pgd = pgd_offset(mm, vmaddr);
434 pud = pud_alloc(mm, pgd, vmaddr);
435 if (!pud)
436 return -ENOMEM;
437 pmd = pmd_alloc(mm, pud, vmaddr);
438 if (!pmd)
439 return -ENOMEM;
440 if (!pmd_present(*pmd) &&
441 __pte_alloc(mm, vma, pmd, vmaddr))
442 return -ENOMEM;
443 /* pmd now points to a valid segment table entry. */
444 rmap = kmalloc(sizeof(*rmap), GFP_KERNEL|__GFP_REPEAT);
445 if (!rmap)
446 return -ENOMEM;
447 /* Link gmap segment table entry location to page table. */
448 page = pmd_page(*pmd);
449 mp = (struct gmap_pgtable *) page->index;
450 rmap->entry = table;
451 spin_lock(&mm->page_table_lock);
452 list_add(&rmap->list, &mp->mapper);
453 spin_unlock(&mm->page_table_lock);
454 /* Set gmap segment table entry to page table. */
455 *table = pmd_val(*pmd) & PAGE_MASK;
456 return vmaddr | (address & ~PMD_MASK);
457 }
458 return -EFAULT;
459 }
460
461 unsigned long gmap_fault(unsigned long address, struct gmap *gmap)
462 {
463 unsigned long rc;
464
465 down_read(&gmap->mm->mmap_sem);
466 rc = __gmap_fault(address, gmap);
467 up_read(&gmap->mm->mmap_sem);
468
469 return rc;
470 }
471 EXPORT_SYMBOL_GPL(gmap_fault);
472
473 void gmap_discard(unsigned long from, unsigned long to, struct gmap *gmap)
474 {
475
476 unsigned long *table, address, size;
477 struct vm_area_struct *vma;
478 struct gmap_pgtable *mp;
479 struct page *page;
480
481 down_read(&gmap->mm->mmap_sem);
482 address = from;
483 while (address < to) {
484 /* Walk the gmap address space page table */
485 table = gmap->table + ((address >> 53) & 0x7ff);
486 if (unlikely(*table & _REGION_ENTRY_INV)) {
487 address = (address + PMD_SIZE) & PMD_MASK;
488 continue;
489 }
490 table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
491 table = table + ((address >> 42) & 0x7ff);
492 if (unlikely(*table & _REGION_ENTRY_INV)) {
493 address = (address + PMD_SIZE) & PMD_MASK;
494 continue;
495 }
496 table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
497 table = table + ((address >> 31) & 0x7ff);
498 if (unlikely(*table & _REGION_ENTRY_INV)) {
499 address = (address + PMD_SIZE) & PMD_MASK;
500 continue;
501 }
502 table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
503 table = table + ((address >> 20) & 0x7ff);
504 if (unlikely(*table & _SEGMENT_ENTRY_INV)) {
505 address = (address + PMD_SIZE) & PMD_MASK;
506 continue;
507 }
508 page = pfn_to_page(*table >> PAGE_SHIFT);
509 mp = (struct gmap_pgtable *) page->index;
510 vma = find_vma(gmap->mm, mp->vmaddr);
511 size = min(to - address, PMD_SIZE - (address & ~PMD_MASK));
512 zap_page_range(vma, mp->vmaddr | (address & ~PMD_MASK),
513 size, NULL);
514 address = (address + PMD_SIZE) & PMD_MASK;
515 }
516 up_read(&gmap->mm->mmap_sem);
517 }
518 EXPORT_SYMBOL_GPL(gmap_discard);
519
520 void gmap_unmap_notifier(struct mm_struct *mm, unsigned long *table)
521 {
522 struct gmap_rmap *rmap, *next;
523 struct gmap_pgtable *mp;
524 struct page *page;
525 int flush;
526
527 flush = 0;
528 spin_lock(&mm->page_table_lock);
529 page = pfn_to_page(__pa(table) >> PAGE_SHIFT);
530 mp = (struct gmap_pgtable *) page->index;
531 list_for_each_entry_safe(rmap, next, &mp->mapper, list) {
532 *rmap->entry =
533 _SEGMENT_ENTRY_INV | _SEGMENT_ENTRY_RO | mp->vmaddr;
534 list_del(&rmap->list);
535 kfree(rmap);
536 flush = 1;
537 }
538 spin_unlock(&mm->page_table_lock);
539 if (flush)
540 __tlb_flush_global();
541 }
542
543 static inline unsigned long *page_table_alloc_pgste(struct mm_struct *mm,
544 unsigned long vmaddr)
545 {
546 struct page *page;
547 unsigned long *table;
548 struct gmap_pgtable *mp;
549
550 page = alloc_page(GFP_KERNEL|__GFP_REPEAT);
551 if (!page)
552 return NULL;
553 mp = kmalloc(sizeof(*mp), GFP_KERNEL|__GFP_REPEAT);
554 if (!mp) {
555 __free_page(page);
556 return NULL;
557 }
558 pgtable_page_ctor(page);
559 mp->vmaddr = vmaddr & PMD_MASK;
560 INIT_LIST_HEAD(&mp->mapper);
561 page->index = (unsigned long) mp;
562 atomic_set(&page->_mapcount, 3);
563 table = (unsigned long *) page_to_phys(page);
564 clear_table(table, _PAGE_TYPE_EMPTY, PAGE_SIZE/2);
565 clear_table(table + PTRS_PER_PTE, 0, PAGE_SIZE/2);
566 return table;
567 }
568
569 static inline void page_table_free_pgste(unsigned long *table)
570 {
571 struct page *page;
572 struct gmap_pgtable *mp;
573
574 page = pfn_to_page(__pa(table) >> PAGE_SHIFT);
575 mp = (struct gmap_pgtable *) page->index;
576 BUG_ON(!list_empty(&mp->mapper));
577 pgtable_page_dtor(page);
578 atomic_set(&page->_mapcount, -1);
579 kfree(mp);
580 __free_page(page);
581 }
582
583 #else /* CONFIG_PGSTE */
584
585 static inline unsigned long *page_table_alloc_pgste(struct mm_struct *mm,
586 unsigned long vmaddr)
587 {
588 return NULL;
589 }
590
591 static inline void page_table_free_pgste(unsigned long *table)
592 {
593 }
594
595 static inline void gmap_unmap_notifier(struct mm_struct *mm,
596 unsigned long *table)
597 {
598 }
599
600 #endif /* CONFIG_PGSTE */
601
602 static inline unsigned int atomic_xor_bits(atomic_t *v, unsigned int bits)
603 {
604 unsigned int old, new;
605
606 do {
607 old = atomic_read(v);
608 new = old ^ bits;
609 } while (atomic_cmpxchg(v, old, new) != old);
610 return new;
611 }
612
613 /*
614 * page table entry allocation/free routines.
615 */
616 unsigned long *page_table_alloc(struct mm_struct *mm, unsigned long vmaddr)
617 {
618 struct page *page;
619 unsigned long *table;
620 unsigned int mask, bit;
621
622 if (mm_has_pgste(mm))
623 return page_table_alloc_pgste(mm, vmaddr);
624 /* Allocate fragments of a 4K page as 1K/2K page table */
625 spin_lock_bh(&mm->context.list_lock);
626 mask = FRAG_MASK;
627 if (!list_empty(&mm->context.pgtable_list)) {
628 page = list_first_entry(&mm->context.pgtable_list,
629 struct page, lru);
630 table = (unsigned long *) page_to_phys(page);
631 mask = atomic_read(&page->_mapcount);
632 mask = mask | (mask >> 4);
633 }
634 if ((mask & FRAG_MASK) == FRAG_MASK) {
635 spin_unlock_bh(&mm->context.list_lock);
636 page = alloc_page(GFP_KERNEL|__GFP_REPEAT);
637 if (!page)
638 return NULL;
639 pgtable_page_ctor(page);
640 atomic_set(&page->_mapcount, 1);
641 table = (unsigned long *) page_to_phys(page);
642 clear_table(table, _PAGE_TYPE_EMPTY, PAGE_SIZE);
643 spin_lock_bh(&mm->context.list_lock);
644 list_add(&page->lru, &mm->context.pgtable_list);
645 } else {
646 for (bit = 1; mask & bit; bit <<= 1)
647 table += PTRS_PER_PTE;
648 mask = atomic_xor_bits(&page->_mapcount, bit);
649 if ((mask & FRAG_MASK) == FRAG_MASK)
650 list_del(&page->lru);
651 }
652 spin_unlock_bh(&mm->context.list_lock);
653 return table;
654 }
655
656 void page_table_free(struct mm_struct *mm, unsigned long *table)
657 {
658 struct page *page;
659 unsigned int bit, mask;
660
661 if (mm_has_pgste(mm)) {
662 gmap_unmap_notifier(mm, table);
663 return page_table_free_pgste(table);
664 }
665 /* Free 1K/2K page table fragment of a 4K page */
666 page = pfn_to_page(__pa(table) >> PAGE_SHIFT);
667 bit = 1 << ((__pa(table) & ~PAGE_MASK)/(PTRS_PER_PTE*sizeof(pte_t)));
668 spin_lock_bh(&mm->context.list_lock);
669 if ((atomic_read(&page->_mapcount) & FRAG_MASK) != FRAG_MASK)
670 list_del(&page->lru);
671 mask = atomic_xor_bits(&page->_mapcount, bit);
672 if (mask & FRAG_MASK)
673 list_add(&page->lru, &mm->context.pgtable_list);
674 spin_unlock_bh(&mm->context.list_lock);
675 if (mask == 0) {
676 pgtable_page_dtor(page);
677 atomic_set(&page->_mapcount, -1);
678 __free_page(page);
679 }
680 }
681
682 static void __page_table_free_rcu(void *table, unsigned bit)
683 {
684 struct page *page;
685
686 if (bit == FRAG_MASK)
687 return page_table_free_pgste(table);
688 /* Free 1K/2K page table fragment of a 4K page */
689 page = pfn_to_page(__pa(table) >> PAGE_SHIFT);
690 if (atomic_xor_bits(&page->_mapcount, bit) == 0) {
691 pgtable_page_dtor(page);
692 atomic_set(&page->_mapcount, -1);
693 __free_page(page);
694 }
695 }
696
697 void page_table_free_rcu(struct mmu_gather *tlb, unsigned long *table)
698 {
699 struct mm_struct *mm;
700 struct page *page;
701 unsigned int bit, mask;
702
703 mm = tlb->mm;
704 if (mm_has_pgste(mm)) {
705 gmap_unmap_notifier(mm, table);
706 table = (unsigned long *) (__pa(table) | FRAG_MASK);
707 tlb_remove_table(tlb, table);
708 return;
709 }
710 bit = 1 << ((__pa(table) & ~PAGE_MASK) / (PTRS_PER_PTE*sizeof(pte_t)));
711 page = pfn_to_page(__pa(table) >> PAGE_SHIFT);
712 spin_lock_bh(&mm->context.list_lock);
713 if ((atomic_read(&page->_mapcount) & FRAG_MASK) != FRAG_MASK)
714 list_del(&page->lru);
715 mask = atomic_xor_bits(&page->_mapcount, bit | (bit << 4));
716 if (mask & FRAG_MASK)
717 list_add_tail(&page->lru, &mm->context.pgtable_list);
718 spin_unlock_bh(&mm->context.list_lock);
719 table = (unsigned long *) (__pa(table) | (bit << 4));
720 tlb_remove_table(tlb, table);
721 }
722
723 void __tlb_remove_table(void *_table)
724 {
725 const unsigned long mask = (FRAG_MASK << 4) | FRAG_MASK;
726 void *table = (void *)((unsigned long) _table & ~mask);
727 unsigned type = (unsigned long) _table & mask;
728
729 if (type)
730 __page_table_free_rcu(table, type);
731 else
732 free_pages((unsigned long) table, ALLOC_ORDER);
733 }
734
735 static void tlb_remove_table_smp_sync(void *arg)
736 {
737 /* Simply deliver the interrupt */
738 }
739
740 static void tlb_remove_table_one(void *table)
741 {
742 /*
743 * This isn't an RCU grace period and hence the page-tables cannot be
744 * assumed to be actually RCU-freed.
745 *
746 * It is however sufficient for software page-table walkers that rely
747 * on IRQ disabling. See the comment near struct mmu_table_batch.
748 */
749 smp_call_function(tlb_remove_table_smp_sync, NULL, 1);
750 __tlb_remove_table(table);
751 }
752
753 static void tlb_remove_table_rcu(struct rcu_head *head)
754 {
755 struct mmu_table_batch *batch;
756 int i;
757
758 batch = container_of(head, struct mmu_table_batch, rcu);
759
760 for (i = 0; i < batch->nr; i++)
761 __tlb_remove_table(batch->tables[i]);
762
763 free_page((unsigned long)batch);
764 }
765
766 void tlb_table_flush(struct mmu_gather *tlb)
767 {
768 struct mmu_table_batch **batch = &tlb->batch;
769
770 if (*batch) {
771 __tlb_flush_mm(tlb->mm);
772 call_rcu_sched(&(*batch)->rcu, tlb_remove_table_rcu);
773 *batch = NULL;
774 }
775 }
776
777 void tlb_remove_table(struct mmu_gather *tlb, void *table)
778 {
779 struct mmu_table_batch **batch = &tlb->batch;
780
781 if (*batch == NULL) {
782 *batch = (struct mmu_table_batch *)
783 __get_free_page(GFP_NOWAIT | __GFP_NOWARN);
784 if (*batch == NULL) {
785 __tlb_flush_mm(tlb->mm);
786 tlb_remove_table_one(table);
787 return;
788 }
789 (*batch)->nr = 0;
790 }
791 (*batch)->tables[(*batch)->nr++] = table;
792 if ((*batch)->nr == MAX_TABLE_BATCH)
793 tlb_table_flush(tlb);
794 }
795
796 /*
797 * switch on pgstes for its userspace process (for kvm)
798 */
799 int s390_enable_sie(void)
800 {
801 struct task_struct *tsk = current;
802 struct mm_struct *mm, *old_mm;
803
804 /* Do we have switched amode? If no, we cannot do sie */
805 if (user_mode == HOME_SPACE_MODE)
806 return -EINVAL;
807
808 /* Do we have pgstes? if yes, we are done */
809 if (mm_has_pgste(tsk->mm))
810 return 0;
811
812 /* lets check if we are allowed to replace the mm */
813 task_lock(tsk);
814 if (!tsk->mm || atomic_read(&tsk->mm->mm_users) > 1 ||
815 #ifdef CONFIG_AIO
816 !hlist_empty(&tsk->mm->ioctx_list) ||
817 #endif
818 tsk->mm != tsk->active_mm) {
819 task_unlock(tsk);
820 return -EINVAL;
821 }
822 task_unlock(tsk);
823
824 /* we copy the mm and let dup_mm create the page tables with_pgstes */
825 tsk->mm->context.alloc_pgste = 1;
826 mm = dup_mm(tsk);
827 tsk->mm->context.alloc_pgste = 0;
828 if (!mm)
829 return -ENOMEM;
830
831 /* Now lets check again if something happened */
832 task_lock(tsk);
833 if (!tsk->mm || atomic_read(&tsk->mm->mm_users) > 1 ||
834 #ifdef CONFIG_AIO
835 !hlist_empty(&tsk->mm->ioctx_list) ||
836 #endif
837 tsk->mm != tsk->active_mm) {
838 mmput(mm);
839 task_unlock(tsk);
840 return -EINVAL;
841 }
842
843 /* ok, we are alone. No ptrace, no threads, etc. */
844 old_mm = tsk->mm;
845 tsk->mm = tsk->active_mm = mm;
846 preempt_disable();
847 update_mm(mm, tsk);
848 atomic_inc(&mm->context.attach_count);
849 atomic_dec(&old_mm->context.attach_count);
850 cpumask_set_cpu(smp_processor_id(), mm_cpumask(mm));
851 preempt_enable();
852 task_unlock(tsk);
853 mmput(old_mm);
854 return 0;
855 }
856 EXPORT_SYMBOL_GPL(s390_enable_sie);
857
858 #if defined(CONFIG_DEBUG_PAGEALLOC) && defined(CONFIG_HIBERNATION)
859 bool kernel_page_present(struct page *page)
860 {
861 unsigned long addr;
862 int cc;
863
864 addr = page_to_phys(page);
865 asm volatile(
866 " lra %1,0(%1)\n"
867 " ipm %0\n"
868 " srl %0,28"
869 : "=d" (cc), "+a" (addr) : : "cc");
870 return cc == 0;
871 }
872 #endif /* CONFIG_HIBERNATION && CONFIG_DEBUG_PAGEALLOC */