?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
nfsd4: typo logical vs bitwise negate for want_mask
[linux-btrfs-devel.git] / arch / s390 / mm / pgtable.c
blob4d1f2bce87b3c5371cd49139019a36cf327b7348
1 /*
2 * Copyright IBM Corp. 2007,2009
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 unsigned long VMALLOC_START = VMALLOC_END - VMALLOC_SIZE;
37 EXPORT_SYMBOL(VMALLOC_START);
38
39 static int __init parse_vmalloc(char *arg)
40 {
41 if (!arg)
42 return -EINVAL;
43 VMALLOC_START = (VMALLOC_END - memparse(arg, &arg)) & PAGE_MASK;
44 return 0;
45 }
46 early_param("vmalloc", parse_vmalloc);
47
48 unsigned long *crst_table_alloc(struct mm_struct *mm)
49 {
50 struct page *page = alloc_pages(GFP_KERNEL, ALLOC_ORDER);
51
52 if (!page)
53 return NULL;
54 return (unsigned long *) page_to_phys(page);
55 }
56
57 void crst_table_free(struct mm_struct *mm, unsigned long *table)
58 {
59 free_pages((unsigned long) table, ALLOC_ORDER);
60 }
61
62 #ifdef CONFIG_64BIT
63 int crst_table_upgrade(struct mm_struct *mm, unsigned long limit)
64 {
65 unsigned long *table, *pgd;
66 unsigned long entry;
67
68 BUG_ON(limit > (1UL << 53));
69 repeat:
70 table = crst_table_alloc(mm);
71 if (!table)
72 return -ENOMEM;
73 spin_lock_bh(&mm->page_table_lock);
74 if (mm->context.asce_limit < limit) {
75 pgd = (unsigned long *) mm->pgd;
76 if (mm->context.asce_limit <= (1UL << 31)) {
77 entry = _REGION3_ENTRY_EMPTY;
78 mm->context.asce_limit = 1UL << 42;
79 mm->context.asce_bits = _ASCE_TABLE_LENGTH |
80 _ASCE_USER_BITS |
81 _ASCE_TYPE_REGION3;
82 } else {
83 entry = _REGION2_ENTRY_EMPTY;
84 mm->context.asce_limit = 1UL << 53;
85 mm->context.asce_bits = _ASCE_TABLE_LENGTH |
86 _ASCE_USER_BITS |
87 _ASCE_TYPE_REGION2;
88 }
89 crst_table_init(table, entry);
90 pgd_populate(mm, (pgd_t *) table, (pud_t *) pgd);
91 mm->pgd = (pgd_t *) table;
92 mm->task_size = mm->context.asce_limit;
93 table = NULL;
94 }
95 spin_unlock_bh(&mm->page_table_lock);
96 if (table)
97 crst_table_free(mm, table);
98 if (mm->context.asce_limit < limit)
99 goto repeat;
100 update_mm(mm, current);
101 return 0;
102 }
103
104 void crst_table_downgrade(struct mm_struct *mm, unsigned long limit)
105 {
106 pgd_t *pgd;
107
108 if (mm->context.asce_limit <= limit)
109 return;
110 __tlb_flush_mm(mm);
111 while (mm->context.asce_limit > limit) {
112 pgd = mm->pgd;
113 switch (pgd_val(*pgd) & _REGION_ENTRY_TYPE_MASK) {
114 case _REGION_ENTRY_TYPE_R2:
115 mm->context.asce_limit = 1UL << 42;
116 mm->context.asce_bits = _ASCE_TABLE_LENGTH |
117 _ASCE_USER_BITS |
118 _ASCE_TYPE_REGION3;
119 break;
120 case _REGION_ENTRY_TYPE_R3:
121 mm->context.asce_limit = 1UL << 31;
122 mm->context.asce_bits = _ASCE_TABLE_LENGTH |
123 _ASCE_USER_BITS |
124 _ASCE_TYPE_SEGMENT;
125 break;
126 default:
127 BUG();
128 }
129 mm->pgd = (pgd_t *) (pgd_val(*pgd) & _REGION_ENTRY_ORIGIN);
130 mm->task_size = mm->context.asce_limit;
131 crst_table_free(mm, (unsigned long *) pgd);
132 }
133 update_mm(mm, current);
134 }
135 #endif
136
137 #ifdef CONFIG_PGSTE
138
139 /**
140 * gmap_alloc - allocate a guest address space
141 * @mm: pointer to the parent mm_struct
142 *
143 * Returns a guest address space structure.
144 */
145 struct gmap *gmap_alloc(struct mm_struct *mm)
146 {
147 struct gmap *gmap;
148 struct page *page;
149 unsigned long *table;
150
151 gmap = kzalloc(sizeof(struct gmap), GFP_KERNEL);
152 if (!gmap)
153 goto out;
154 INIT_LIST_HEAD(&gmap->crst_list);
155 gmap->mm = mm;
156 page = alloc_pages(GFP_KERNEL, ALLOC_ORDER);
157 if (!page)
158 goto out_free;
159 list_add(&page->lru, &gmap->crst_list);
160 table = (unsigned long *) page_to_phys(page);
161 crst_table_init(table, _REGION1_ENTRY_EMPTY);
162 gmap->table = table;
163 list_add(&gmap->list, &mm->context.gmap_list);
164 return gmap;
165
166 out_free:
167 kfree(gmap);
168 out:
169 return NULL;
170 }
171 EXPORT_SYMBOL_GPL(gmap_alloc);
172
173 static int gmap_unlink_segment(struct gmap *gmap, unsigned long *table)
174 {
175 struct gmap_pgtable *mp;
176 struct gmap_rmap *rmap;
177 struct page *page;
178
179 if (*table & _SEGMENT_ENTRY_INV)
180 return 0;
181 page = pfn_to_page(*table >> PAGE_SHIFT);
182 mp = (struct gmap_pgtable *) page->index;
183 list_for_each_entry(rmap, &mp->mapper, list) {
184 if (rmap->entry != table)
185 continue;
186 list_del(&rmap->list);
187 kfree(rmap);
188 break;
189 }
190 *table = _SEGMENT_ENTRY_INV | _SEGMENT_ENTRY_RO | mp->vmaddr;
191 return 1;
192 }
193
194 static void gmap_flush_tlb(struct gmap *gmap)
195 {
196 if (MACHINE_HAS_IDTE)
197 __tlb_flush_idte((unsigned long) gmap->table |
198 _ASCE_TYPE_REGION1);
199 else
200 __tlb_flush_global();
201 }
202
203 /**
204 * gmap_free - free a guest address space
205 * @gmap: pointer to the guest address space structure
206 */
207 void gmap_free(struct gmap *gmap)
208 {
209 struct page *page, *next;
210 unsigned long *table;
211 int i;
212
213
214 /* Flush tlb. */
215 if (MACHINE_HAS_IDTE)
216 __tlb_flush_idte((unsigned long) gmap->table |
217 _ASCE_TYPE_REGION1);
218 else
219 __tlb_flush_global();
220
221 /* Free all segment & region tables. */
222 down_read(&gmap->mm->mmap_sem);
223 list_for_each_entry_safe(page, next, &gmap->crst_list, lru) {
224 table = (unsigned long *) page_to_phys(page);
225 if ((*table & _REGION_ENTRY_TYPE_MASK) == 0)
226 /* Remove gmap rmap structures for segment table. */
227 for (i = 0; i < PTRS_PER_PMD; i++, table++)
228 gmap_unlink_segment(gmap, table);
229 __free_pages(page, ALLOC_ORDER);
230 }
231 up_read(&gmap->mm->mmap_sem);
232 list_del(&gmap->list);
233 kfree(gmap);
234 }
235 EXPORT_SYMBOL_GPL(gmap_free);
236
237 /**
238 * gmap_enable - switch primary space to the guest address space
239 * @gmap: pointer to the guest address space structure
240 */
241 void gmap_enable(struct gmap *gmap)
242 {
243 /* Load primary space page table origin. */
244 S390_lowcore.user_asce = _ASCE_TYPE_REGION1 | _ASCE_TABLE_LENGTH |
245 _ASCE_USER_BITS | __pa(gmap->table);
246 asm volatile("lctlg 1,1,%0\n" : : "m" (S390_lowcore.user_asce) );
247 S390_lowcore.gmap = (unsigned long) gmap;
248 }
249 EXPORT_SYMBOL_GPL(gmap_enable);
250
251 /**
252 * gmap_disable - switch back to the standard primary address space
253 * @gmap: pointer to the guest address space structure
254 */
255 void gmap_disable(struct gmap *gmap)
256 {
257 /* Load primary space page table origin. */
258 S390_lowcore.user_asce =
259 gmap->mm->context.asce_bits | __pa(gmap->mm->pgd);
260 asm volatile("lctlg 1,1,%0\n" : : "m" (S390_lowcore.user_asce) );
261 S390_lowcore.gmap = 0UL;
262 }
263 EXPORT_SYMBOL_GPL(gmap_disable);
264
265 static int gmap_alloc_table(struct gmap *gmap,
266 unsigned long *table, unsigned long init)
267 {
268 struct page *page;
269 unsigned long *new;
270
271 page = alloc_pages(GFP_KERNEL, ALLOC_ORDER);
272 if (!page)
273 return -ENOMEM;
274 new = (unsigned long *) page_to_phys(page);
275 crst_table_init(new, init);
276 down_read(&gmap->mm->mmap_sem);
277 if (*table & _REGION_ENTRY_INV) {
278 list_add(&page->lru, &gmap->crst_list);
279 *table = (unsigned long) new | _REGION_ENTRY_LENGTH |
280 (*table & _REGION_ENTRY_TYPE_MASK);
281 } else
282 __free_pages(page, ALLOC_ORDER);
283 up_read(&gmap->mm->mmap_sem);
284 return 0;
285 }
286
287 /**
288 * gmap_unmap_segment - unmap segment from the guest address space
289 * @gmap: pointer to the guest address space structure
290 * @addr: address in the guest address space
291 * @len: length of the memory area to unmap
292 *
293 * Returns 0 if the unmap succeded, -EINVAL if not.
294 */
295 int gmap_unmap_segment(struct gmap *gmap, unsigned long to, unsigned long len)
296 {
297 unsigned long *table;
298 unsigned long off;
299 int flush;
300
301 if ((to | len) & (PMD_SIZE - 1))
302 return -EINVAL;
303 if (len == 0 || to + len < to)
304 return -EINVAL;
305
306 flush = 0;
307 down_read(&gmap->mm->mmap_sem);
308 for (off = 0; off < len; off += PMD_SIZE) {
309 /* Walk the guest addr space page table */
310 table = gmap->table + (((to + off) >> 53) & 0x7ff);
311 if (*table & _REGION_ENTRY_INV)
312 return 0;
313 table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
314 table = table + (((to + off) >> 42) & 0x7ff);
315 if (*table & _REGION_ENTRY_INV)
316 return 0;
317 table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
318 table = table + (((to + off) >> 31) & 0x7ff);
319 if (*table & _REGION_ENTRY_INV)
320 return 0;
321 table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
322 table = table + (((to + off) >> 20) & 0x7ff);
323
324 /* Clear segment table entry in guest address space. */
325 flush |= gmap_unlink_segment(gmap, table);
326 *table = _SEGMENT_ENTRY_INV;
327 }
328 up_read(&gmap->mm->mmap_sem);
329 if (flush)
330 gmap_flush_tlb(gmap);
331 return 0;
332 }
333 EXPORT_SYMBOL_GPL(gmap_unmap_segment);
334
335 /**
336 * gmap_mmap_segment - map a segment to the guest address space
337 * @gmap: pointer to the guest address space structure
338 * @from: source address in the parent address space
339 * @to: target address in the guest address space
340 *
341 * Returns 0 if the mmap succeded, -EINVAL or -ENOMEM if not.
342 */
343 int gmap_map_segment(struct gmap *gmap, unsigned long from,
344 unsigned long to, unsigned long len)
345 {
346 unsigned long *table;
347 unsigned long off;
348 int flush;
349
350 if ((from | to | len) & (PMD_SIZE - 1))
351 return -EINVAL;
352 if (len == 0 || from + len > PGDIR_SIZE ||
353 from + len < from || to + len < to)
354 return -EINVAL;
355
356 flush = 0;
357 down_read(&gmap->mm->mmap_sem);
358 for (off = 0; off < len; off += PMD_SIZE) {
359 /* Walk the gmap address space page table */
360 table = gmap->table + (((to + off) >> 53) & 0x7ff);
361 if ((*table & _REGION_ENTRY_INV) &&
362 gmap_alloc_table(gmap, table, _REGION2_ENTRY_EMPTY))
363 goto out_unmap;
364 table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
365 table = table + (((to + off) >> 42) & 0x7ff);
366 if ((*table & _REGION_ENTRY_INV) &&
367 gmap_alloc_table(gmap, table, _REGION3_ENTRY_EMPTY))
368 goto out_unmap;
369 table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
370 table = table + (((to + off) >> 31) & 0x7ff);
371 if ((*table & _REGION_ENTRY_INV) &&
372 gmap_alloc_table(gmap, table, _SEGMENT_ENTRY_EMPTY))
373 goto out_unmap;
374 table = (unsigned long *) (*table & _REGION_ENTRY_ORIGIN);
375 table = table + (((to + off) >> 20) & 0x7ff);
376
377 /* Store 'from' address in an invalid segment table entry. */
378 flush |= gmap_unlink_segment(gmap, table);
379 *table = _SEGMENT_ENTRY_INV | _SEGMENT_ENTRY_RO | (from + off);
380 }
381 up_read(&gmap->mm->mmap_sem);
382 if (flush)
383 gmap_flush_tlb(gmap);
384 return 0;
385
386 out_unmap:
387 up_read(&gmap->mm->mmap_sem);
388 gmap_unmap_segment(gmap, to, len);
389 return -ENOMEM;
390 }
391 EXPORT_SYMBOL_GPL(gmap_map_segment);
392
393 unsigned long gmap_fault(unsigned long address, struct gmap *gmap)
394 {
395 unsigned long *table, vmaddr, segment;
396 struct mm_struct *mm;
397 struct gmap_pgtable *mp;
398 struct gmap_rmap *rmap;
399 struct vm_area_struct *vma;
400 struct page *page;
401 pgd_t *pgd;
402 pud_t *pud;
403 pmd_t *pmd;
404
405 current->thread.gmap_addr = address;
406 mm = gmap->mm;
407 /* Walk the gmap address space page table */
408 table = gmap->table + ((address >> 53) & 0x7ff);
409 if (unlikely(*table & _REGION_ENTRY_INV))
410 return -EFAULT;
411 table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
412 table = table + ((address >> 42) & 0x7ff);
413 if (unlikely(*table & _REGION_ENTRY_INV))
414 return -EFAULT;
415 table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
416 table = table + ((address >> 31) & 0x7ff);
417 if (unlikely(*table & _REGION_ENTRY_INV))
418 return -EFAULT;
419 table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
420 table = table + ((address >> 20) & 0x7ff);
421
422 /* Convert the gmap address to an mm address. */
423 segment = *table;
424 if (likely(!(segment & _SEGMENT_ENTRY_INV))) {
425 page = pfn_to_page(segment >> PAGE_SHIFT);
426 mp = (struct gmap_pgtable *) page->index;
427 return mp->vmaddr | (address & ~PMD_MASK);
428 } else if (segment & _SEGMENT_ENTRY_RO) {
429 vmaddr = segment & _SEGMENT_ENTRY_ORIGIN;
430 vma = find_vma(mm, vmaddr);
431 if (!vma || vma->vm_start > vmaddr)
432 return -EFAULT;
433
434 /* Walk the parent mm page table */
435 pgd = pgd_offset(mm, vmaddr);
436 pud = pud_alloc(mm, pgd, vmaddr);
437 if (!pud)
438 return -ENOMEM;
439 pmd = pmd_alloc(mm, pud, vmaddr);
440 if (!pmd)
441 return -ENOMEM;
442 if (!pmd_present(*pmd) &&
443 __pte_alloc(mm, vma, pmd, vmaddr))
444 return -ENOMEM;
445 /* pmd now points to a valid segment table entry. */
446 rmap = kmalloc(sizeof(*rmap), GFP_KERNEL|__GFP_REPEAT);
447 if (!rmap)
448 return -ENOMEM;
449 /* Link gmap segment table entry location to page table. */
450 page = pmd_page(*pmd);
451 mp = (struct gmap_pgtable *) page->index;
452 rmap->entry = table;
453 list_add(&rmap->list, &mp->mapper);
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 EXPORT_SYMBOL_GPL(gmap_fault);
462
463 void gmap_unmap_notifier(struct mm_struct *mm, unsigned long *table)
464 {
465 struct gmap_rmap *rmap, *next;
466 struct gmap_pgtable *mp;
467 struct page *page;
468 int flush;
469
470 flush = 0;
471 spin_lock(&mm->page_table_lock);
472 page = pfn_to_page(__pa(table) >> PAGE_SHIFT);
473 mp = (struct gmap_pgtable *) page->index;
474 list_for_each_entry_safe(rmap, next, &mp->mapper, list) {
475 *rmap->entry =
476 _SEGMENT_ENTRY_INV | _SEGMENT_ENTRY_RO | mp->vmaddr;
477 list_del(&rmap->list);
478 kfree(rmap);
479 flush = 1;
480 }
481 spin_unlock(&mm->page_table_lock);
482 if (flush)
483 __tlb_flush_global();
484 }
485
486 static inline unsigned long *page_table_alloc_pgste(struct mm_struct *mm,
487 unsigned long vmaddr)
488 {
489 struct page *page;
490 unsigned long *table;
491 struct gmap_pgtable *mp;
492
493 page = alloc_page(GFP_KERNEL|__GFP_REPEAT);
494 if (!page)
495 return NULL;
496 mp = kmalloc(sizeof(*mp), GFP_KERNEL|__GFP_REPEAT);
497 if (!mp) {
498 __free_page(page);
499 return NULL;
500 }
501 pgtable_page_ctor(page);
502 mp->vmaddr = vmaddr & PMD_MASK;
503 INIT_LIST_HEAD(&mp->mapper);
504 page->index = (unsigned long) mp;
505 atomic_set(&page->_mapcount, 3);
506 table = (unsigned long *) page_to_phys(page);
507 clear_table(table, _PAGE_TYPE_EMPTY, PAGE_SIZE/2);
508 clear_table(table + PTRS_PER_PTE, 0, PAGE_SIZE/2);
509 return table;
510 }
511
512 static inline void page_table_free_pgste(unsigned long *table)
513 {
514 struct page *page;
515 struct gmap_pgtable *mp;
516
517 page = pfn_to_page(__pa(table) >> PAGE_SHIFT);
518 mp = (struct gmap_pgtable *) page->index;
519 BUG_ON(!list_empty(&mp->mapper));
520 pgtable_page_ctor(page);
521 atomic_set(&page->_mapcount, -1);
522 kfree(mp);
523 __free_page(page);
524 }
525
526 #else /* CONFIG_PGSTE */
527
528 static inline unsigned long *page_table_alloc_pgste(struct mm_struct *mm,
529 unsigned long vmaddr)
530 {
531 return NULL;
532 }
533
534 static inline void page_table_free_pgste(unsigned long *table)
535 {
536 }
537
538 static inline void gmap_unmap_notifier(struct mm_struct *mm,
539 unsigned long *table)
540 {
541 }
542
543 #endif /* CONFIG_PGSTE */
544
545 static inline unsigned int atomic_xor_bits(atomic_t *v, unsigned int bits)
546 {
547 unsigned int old, new;
548
549 do {
550 old = atomic_read(v);
551 new = old ^ bits;
552 } while (atomic_cmpxchg(v, old, new) != old);
553 return new;
554 }
555
556 /*
557 * page table entry allocation/free routines.
558 */
559 unsigned long *page_table_alloc(struct mm_struct *mm, unsigned long vmaddr)
560 {
561 struct page *page;
562 unsigned long *table;
563 unsigned int mask, bit;
564
565 if (mm_has_pgste(mm))
566 return page_table_alloc_pgste(mm, vmaddr);
567 /* Allocate fragments of a 4K page as 1K/2K page table */
568 spin_lock_bh(&mm->context.list_lock);
569 mask = FRAG_MASK;
570 if (!list_empty(&mm->context.pgtable_list)) {
571 page = list_first_entry(&mm->context.pgtable_list,
572 struct page, lru);
573 table = (unsigned long *) page_to_phys(page);
574 mask = atomic_read(&page->_mapcount);
575 mask = mask | (mask >> 4);
576 }
577 if ((mask & FRAG_MASK) == FRAG_MASK) {
578 spin_unlock_bh(&mm->context.list_lock);
579 page = alloc_page(GFP_KERNEL|__GFP_REPEAT);
580 if (!page)
581 return NULL;
582 pgtable_page_ctor(page);
583 atomic_set(&page->_mapcount, 1);
584 table = (unsigned long *) page_to_phys(page);
585 clear_table(table, _PAGE_TYPE_EMPTY, PAGE_SIZE);
586 spin_lock_bh(&mm->context.list_lock);
587 list_add(&page->lru, &mm->context.pgtable_list);
588 } else {
589 for (bit = 1; mask & bit; bit <<= 1)
590 table += PTRS_PER_PTE;
591 mask = atomic_xor_bits(&page->_mapcount, bit);
592 if ((mask & FRAG_MASK) == FRAG_MASK)
593 list_del(&page->lru);
594 }
595 spin_unlock_bh(&mm->context.list_lock);
596 return table;
597 }
598
599 void page_table_free(struct mm_struct *mm, unsigned long *table)
600 {
601 struct page *page;
602 unsigned int bit, mask;
603
604 if (mm_has_pgste(mm)) {
605 gmap_unmap_notifier(mm, table);
606 return page_table_free_pgste(table);
607 }
608 /* Free 1K/2K page table fragment of a 4K page */
609 page = pfn_to_page(__pa(table) >> PAGE_SHIFT);
610 bit = 1 << ((__pa(table) & ~PAGE_MASK)/(PTRS_PER_PTE*sizeof(pte_t)));
611 spin_lock_bh(&mm->context.list_lock);
612 if ((atomic_read(&page->_mapcount) & FRAG_MASK) != FRAG_MASK)
613 list_del(&page->lru);
614 mask = atomic_xor_bits(&page->_mapcount, bit);
615 if (mask & FRAG_MASK)
616 list_add(&page->lru, &mm->context.pgtable_list);
617 spin_unlock_bh(&mm->context.list_lock);
618 if (mask == 0) {
619 pgtable_page_dtor(page);
620 atomic_set(&page->_mapcount, -1);
621 __free_page(page);
622 }
623 }
624
625 #ifdef CONFIG_HAVE_RCU_TABLE_FREE
626
627 static void __page_table_free_rcu(void *table, unsigned bit)
628 {
629 struct page *page;
630
631 if (bit == FRAG_MASK)
632 return page_table_free_pgste(table);
633 /* Free 1K/2K page table fragment of a 4K page */
634 page = pfn_to_page(__pa(table) >> PAGE_SHIFT);
635 if (atomic_xor_bits(&page->_mapcount, bit) == 0) {
636 pgtable_page_dtor(page);
637 atomic_set(&page->_mapcount, -1);
638 __free_page(page);
639 }
640 }
641
642 void page_table_free_rcu(struct mmu_gather *tlb, unsigned long *table)
643 {
644 struct mm_struct *mm;
645 struct page *page;
646 unsigned int bit, mask;
647
648 mm = tlb->mm;
649 if (mm_has_pgste(mm)) {
650 gmap_unmap_notifier(mm, table);
651 table = (unsigned long *) (__pa(table) | FRAG_MASK);
652 tlb_remove_table(tlb, table);
653 return;
654 }
655 bit = 1 << ((__pa(table) & ~PAGE_MASK) / (PTRS_PER_PTE*sizeof(pte_t)));
656 page = pfn_to_page(__pa(table) >> PAGE_SHIFT);
657 spin_lock_bh(&mm->context.list_lock);
658 if ((atomic_read(&page->_mapcount) & FRAG_MASK) != FRAG_MASK)
659 list_del(&page->lru);
660 mask = atomic_xor_bits(&page->_mapcount, bit | (bit << 4));
661 if (mask & FRAG_MASK)
662 list_add_tail(&page->lru, &mm->context.pgtable_list);
663 spin_unlock_bh(&mm->context.list_lock);
664 table = (unsigned long *) (__pa(table) | (bit << 4));
665 tlb_remove_table(tlb, table);
666 }
667
668 void __tlb_remove_table(void *_table)
669 {
670 void *table = (void *)((unsigned long) _table & PAGE_MASK);
671 unsigned type = (unsigned long) _table & ~PAGE_MASK;
672
673 if (type)
674 __page_table_free_rcu(table, type);
675 else
676 free_pages((unsigned long) table, ALLOC_ORDER);
677 }
678
679 #endif
680
681 /*
682 * switch on pgstes for its userspace process (for kvm)
683 */
684 int s390_enable_sie(void)
685 {
686 struct task_struct *tsk = current;
687 struct mm_struct *mm, *old_mm;
688
689 /* Do we have switched amode? If no, we cannot do sie */
690 if (user_mode == HOME_SPACE_MODE)
691 return -EINVAL;
692
693 /* Do we have pgstes? if yes, we are done */
694 if (mm_has_pgste(tsk->mm))
695 return 0;
696
697 /* lets check if we are allowed to replace the mm */
698 task_lock(tsk);
699 if (!tsk->mm || atomic_read(&tsk->mm->mm_users) > 1 ||
700 #ifdef CONFIG_AIO
701 !hlist_empty(&tsk->mm->ioctx_list) ||
702 #endif
703 tsk->mm != tsk->active_mm) {
704 task_unlock(tsk);
705 return -EINVAL;
706 }
707 task_unlock(tsk);
708
709 /* we copy the mm and let dup_mm create the page tables with_pgstes */
710 tsk->mm->context.alloc_pgste = 1;
711 mm = dup_mm(tsk);
712 tsk->mm->context.alloc_pgste = 0;
713 if (!mm)
714 return -ENOMEM;
715
716 /* Now lets check again if something happened */
717 task_lock(tsk);
718 if (!tsk->mm || atomic_read(&tsk->mm->mm_users) > 1 ||
719 #ifdef CONFIG_AIO
720 !hlist_empty(&tsk->mm->ioctx_list) ||
721 #endif
722 tsk->mm != tsk->active_mm) {
723 mmput(mm);
724 task_unlock(tsk);
725 return -EINVAL;
726 }
727
728 /* ok, we are alone. No ptrace, no threads, etc. */
729 old_mm = tsk->mm;
730 tsk->mm = tsk->active_mm = mm;
731 preempt_disable();
732 update_mm(mm, tsk);
733 atomic_inc(&mm->context.attach_count);
734 atomic_dec(&old_mm->context.attach_count);
735 cpumask_set_cpu(smp_processor_id(), mm_cpumask(mm));
736 preempt_enable();
737 task_unlock(tsk);
738 mmput(old_mm);
739 return 0;
740 }
741 EXPORT_SYMBOL_GPL(s390_enable_sie);
742
743 #if defined(CONFIG_DEBUG_PAGEALLOC) && defined(CONFIG_HIBERNATION)
744 bool kernel_page_present(struct page *page)
745 {
746 unsigned long addr;
747 int cc;
748
749 addr = page_to_phys(page);
750 asm volatile(
751 " lra %1,0(%1)\n"
752 " ipm %0\n"
753 " srl %0,28"
754 : "=d" (cc), "+a" (addr) : : "cc");
755 return cc == 0;
756 }
757 #endif /* CONFIG_HIBERNATION && CONFIG_DEBUG_PAGEALLOC */
Linux Btrfs Development