arch/s390/mm/pgtable.c

   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/pgtable.h>
  22 #include <asm/pgalloc.h>
  23 #include <asm/tlb.h>
  24 #include <asm/tlbflush.h>
  25 #include <asm/mmu_context.h>
  26
  27 #ifndef CONFIG_64BIT
  28 #define ALLOC_ORDER     1
  29 #define FRAG_MASK       0x0f
  30 #else
  31 #define ALLOC_ORDER     2
  32 #define FRAG_MASK       0x03
  33 #endif
  34
  35
  36 unsigned long *crst_table_alloc(struct mm_struct *mm)
  37 {
  38         struct page *page = alloc_pages(GFP_KERNEL, ALLOC_ORDER);
  39
  40         if (!page)
  41                 return NULL;
  42         return (unsigned long *) page_to_phys(page);
  43 }
  44
  45 void crst_table_free(struct mm_struct *mm, unsigned long *table)
  46 {
  47         free_pages((unsigned long) table, ALLOC_ORDER);
  48 }
  49
  50 #ifdef CONFIG_64BIT
  51 int crst_table_upgrade(struct mm_struct *mm, unsigned long limit)
  52 {
  53         unsigned long *table, *pgd;
  54         unsigned long entry;
  55
  56         BUG_ON(limit > (1UL << 53));
  57 repeat:
  58         table = crst_table_alloc(mm);
  59         if (!table)
  60                 return -ENOMEM;
  61         spin_lock_bh(&mm->page_table_lock);
  62         if (mm->context.asce_limit < limit) {
  63                 pgd = (unsigned long *) mm->pgd;
  64                 if (mm->context.asce_limit <= (1UL << 31)) {
  65                         entry = _REGION3_ENTRY_EMPTY;
  66                         mm->context.asce_limit = 1UL << 42;
  67                         mm->context.asce_bits = _ASCE_TABLE_LENGTH |
  68                                                 _ASCE_USER_BITS |
  69                                                 _ASCE_TYPE_REGION3;
  70                 } else {
  71                         entry = _REGION2_ENTRY_EMPTY;
  72                         mm->context.asce_limit = 1UL << 53;
  73                         mm->context.asce_bits = _ASCE_TABLE_LENGTH |
  74                                                 _ASCE_USER_BITS |
  75                                                 _ASCE_TYPE_REGION2;
  76                 }
  77                 crst_table_init(table, entry);
  78                 pgd_populate(mm, (pgd_t *) table, (pud_t *) pgd);
  79                 mm->pgd = (pgd_t *) table;
  80                 mm->task_size = mm->context.asce_limit;
  81                 table = NULL;
  82         }
  83         spin_unlock_bh(&mm->page_table_lock);
  84         if (table)
  85                 crst_table_free(mm, table);
  86         if (mm->context.asce_limit < limit)
  87                 goto repeat;
  88         return 0;
  89 }
  90
  91 void crst_table_downgrade(struct mm_struct *mm, unsigned long limit)
  92 {
  93         pgd_t *pgd;
  94
  95         while (mm->context.asce_limit > limit) {
  96                 pgd = mm->pgd;
  97                 switch (pgd_val(*pgd) & _REGION_ENTRY_TYPE_MASK) {
  98                 case _REGION_ENTRY_TYPE_R2:
  99                         mm->context.asce_limit = 1UL << 42;
 100                         mm->context.asce_bits = _ASCE_TABLE_LENGTH |
 101                                                 _ASCE_USER_BITS |
 102                                                 _ASCE_TYPE_REGION3;
 103                         break;
 104                 case _REGION_ENTRY_TYPE_R3:
 105                         mm->context.asce_limit = 1UL << 31;
 106                         mm->context.asce_bits = _ASCE_TABLE_LENGTH |
 107                                                 _ASCE_USER_BITS |
 108                                                 _ASCE_TYPE_SEGMENT;
 109                         break;
 110                 default:
 111                         BUG();
 112                 }
 113                 mm->pgd = (pgd_t *) (pgd_val(*pgd) & _REGION_ENTRY_ORIGIN);
 114                 mm->task_size = mm->context.asce_limit;
 115                 crst_table_free(mm, (unsigned long *) pgd);
 116         }
 117 }
 118 #endif
 119
 120 #ifdef CONFIG_PGSTE
 121
 122 /**
 123  * gmap_alloc - allocate a guest address space
 124  * @mm: pointer to the parent mm_struct
 125  *
 126  * Returns a guest address space structure.
 127  */
 128 struct gmap *gmap_alloc(struct mm_struct *mm)
 129 {
 130         struct gmap *gmap;
 131         struct page *page;
 132         unsigned long *table;
 133
 134         gmap = kzalloc(sizeof(struct gmap), GFP_KERNEL);
 135         if (!gmap)
 136                 goto out;
 137         INIT_LIST_HEAD(&gmap->crst_list);
 138         gmap->mm = mm;
 139         page = alloc_pages(GFP_KERNEL, ALLOC_ORDER);
 140         if (!page)
 141                 goto out_free;
 142         list_add(&page->lru, &gmap->crst_list);
 143         table = (unsigned long *) page_to_phys(page);
 144         crst_table_init(table, _REGION1_ENTRY_EMPTY);
 145         gmap->table = table;
 146         gmap->asce = _ASCE_TYPE_REGION1 | _ASCE_TABLE_LENGTH |
 147                      _ASCE_USER_BITS | __pa(table);
 148         list_add(&gmap->list, &mm->context.gmap_list);
 149         return gmap;
 150
 151 out_free:
 152         kfree(gmap);
 153 out:
 154         return NULL;
 155 }
 156 EXPORT_SYMBOL_GPL(gmap_alloc);
 157
 158 static int gmap_unlink_segment(struct gmap *gmap, unsigned long *table)
 159 {
 160         struct gmap_pgtable *mp;
 161         struct gmap_rmap *rmap;
 162         struct page *page;
 163
 164         if (*table & _SEGMENT_ENTRY_INV)
 165                 return 0;
 166         page = pfn_to_page(*table >> PAGE_SHIFT);
 167         mp = (struct gmap_pgtable *) page->index;
 168         list_for_each_entry(rmap, &mp->mapper, list) {
 169                 if (rmap->entry != table)
 170                         continue;
 171                 list_del(&rmap->list);
 172                 kfree(rmap);
 173                 break;
 174         }
 175         *table = _SEGMENT_ENTRY_INV | _SEGMENT_ENTRY_RO | mp->vmaddr;
 176         return 1;
 177 }
 178
 179 static void gmap_flush_tlb(struct gmap *gmap)
 180 {
 181         if (MACHINE_HAS_IDTE)
 182                 __tlb_flush_idte((unsigned long) gmap->table |
 183                                  _ASCE_TYPE_REGION1);
 184         else
 185                 __tlb_flush_global();
 186 }
 187
 188 /**
 189  * gmap_free - free a guest address space
 190  * @gmap: pointer to the guest address space structure
 191  */
 192 void gmap_free(struct gmap *gmap)
 193 {
 194         struct page *page, *next;
 195         unsigned long *table;
 196         int i;
 197
 198
 199         /* Flush tlb. */
 200         if (MACHINE_HAS_IDTE)
 201                 __tlb_flush_idte((unsigned long) gmap->table |
 202                                  _ASCE_TYPE_REGION1);
 203         else
 204                 __tlb_flush_global();
 205
 206         /* Free all segment & region tables. */
 207         down_read(&gmap->mm->mmap_sem);
 208         spin_lock(&gmap->mm->page_table_lock);
 209         list_for_each_entry_safe(page, next, &gmap->crst_list, lru) {
 210                 table = (unsigned long *) page_to_phys(page);
 211                 if ((*table & _REGION_ENTRY_TYPE_MASK) == 0)
 212                         /* Remove gmap rmap structures for segment table. */
 213                         for (i = 0; i < PTRS_PER_PMD; i++, table++)
 214                                 gmap_unlink_segment(gmap, table);
 215                 __free_pages(page, ALLOC_ORDER);
 216         }
 217         spin_unlock(&gmap->mm->page_table_lock);
 218         up_read(&gmap->mm->mmap_sem);
 219         list_del(&gmap->list);
 220         kfree(gmap);
 221 }
 222 EXPORT_SYMBOL_GPL(gmap_free);
 223
 224 /**
 225  * gmap_enable - switch primary space to the guest address space
 226  * @gmap: pointer to the guest address space structure
 227  */
 228 void gmap_enable(struct gmap *gmap)
 229 {
 230         S390_lowcore.gmap = (unsigned long) gmap;
 231 }
 232 EXPORT_SYMBOL_GPL(gmap_enable);
 233
 234 /**
 235  * gmap_disable - switch back to the standard primary address space
 236  * @gmap: pointer to the guest address space structure
 237  */
 238 void gmap_disable(struct gmap *gmap)
 239 {
 240         S390_lowcore.gmap = 0UL;
 241 }
 242 EXPORT_SYMBOL_GPL(gmap_disable);
 243
 244 /*
 245  * gmap_alloc_table is assumed to be called with mmap_sem held
 246  */
 247 static int gmap_alloc_table(struct gmap *gmap,
 248                                unsigned long *table, unsigned long init)
 249 {
 250         struct page *page;
 251         unsigned long *new;
 252
 253         /* since we dont free the gmap table until gmap_free we can unlock */
 254         spin_unlock(&gmap->mm->page_table_lock);
 255         page = alloc_pages(GFP_KERNEL, ALLOC_ORDER);
 256         spin_lock(&gmap->mm->page_table_lock);
 257         if (!page)
 258                 return -ENOMEM;
 259         new = (unsigned long *) page_to_phys(page);
 260         crst_table_init(new, init);
 261         if (*table & _REGION_ENTRY_INV) {
 262                 list_add(&page->lru, &gmap->crst_list);
 263                 *table = (unsigned long) new | _REGION_ENTRY_LENGTH |
 264                         (*table & _REGION_ENTRY_TYPE_MASK);
 265         } else
 266                 __free_pages(page, ALLOC_ORDER);
 267         return 0;
 268 }
 269
 270 /**
 271  * gmap_unmap_segment - unmap segment from the guest address space
 272  * @gmap: pointer to the guest address space structure
 273  * @addr: address in the guest address space
 274  * @len: length of the memory area to unmap
 275  *
 276  * Returns 0 if the unmap succeded, -EINVAL if not.
 277  */
 278 int gmap_unmap_segment(struct gmap *gmap, unsigned long to, unsigned long len)
 279 {
 280         unsigned long *table;
 281         unsigned long off;
 282         int flush;
 283
 284         if ((to | len) & (PMD_SIZE - 1))
 285                 return -EINVAL;
 286         if (len == 0 || to + len < to)
 287                 return -EINVAL;
 288
 289         flush = 0;
 290         down_read(&gmap->mm->mmap_sem);
 291         spin_lock(&gmap->mm->page_table_lock);
 292         for (off = 0; off < len; off += PMD_SIZE) {
 293                 /* Walk the guest addr space page table */
 294                 table = gmap->table + (((to + off) >> 53) & 0x7ff);
 295                 if (*table & _REGION_ENTRY_INV)
 296                         goto out;
 297                 table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
 298                 table = table + (((to + off) >> 42) & 0x7ff);
 299                 if (*table & _REGION_ENTRY_INV)
 300                         goto out;
 301                 table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
 302                 table = table + (((to + off) >> 31) & 0x7ff);
 303                 if (*table & _REGION_ENTRY_INV)
 304                         goto out;
 305                 table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
 306                 table = table + (((to + off) >> 20) & 0x7ff);
 307
 308                 /* Clear segment table entry in guest address space. */
 309                 flush |= gmap_unlink_segment(gmap, table);
 310                 *table = _SEGMENT_ENTRY_INV;
 311         }
 312 out:
 313         spin_unlock(&gmap->mm->page_table_lock);
 314         up_read(&gmap->mm->mmap_sem);
 315         if (flush)
 316                 gmap_flush_tlb(gmap);
 317         return 0;
 318 }
 319 EXPORT_SYMBOL_GPL(gmap_unmap_segment);
 320
 321 /**
 322  * gmap_mmap_segment - map a segment to the guest address space
 323  * @gmap: pointer to the guest address space structure
 324  * @from: source address in the parent address space
 325  * @to: target address in the guest address space
 326  *
 327  * Returns 0 if the mmap succeded, -EINVAL or -ENOMEM if not.
 328  */
 329 int gmap_map_segment(struct gmap *gmap, unsigned long from,
 330                      unsigned long to, unsigned long len)
 331 {
 332         unsigned long *table;
 333         unsigned long off;
 334         int flush;
 335
 336         if ((from | to | len) & (PMD_SIZE - 1))
 337                 return -EINVAL;
 338         if (len == 0 || from + len > PGDIR_SIZE ||
 339             from + len < from || to + len < to)
 340                 return -EINVAL;
 341
 342         flush = 0;
 343         down_read(&gmap->mm->mmap_sem);
 344         spin_lock(&gmap->mm->page_table_lock);
 345         for (off = 0; off < len; off += PMD_SIZE) {
 346                 /* Walk the gmap address space page table */
 347                 table = gmap->table + (((to + off) >> 53) & 0x7ff);
 348                 if ((*table & _REGION_ENTRY_INV) &&
 349                     gmap_alloc_table(gmap, table, _REGION2_ENTRY_EMPTY))
 350                         goto out_unmap;
 351                 table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
 352                 table = table + (((to + off) >> 42) & 0x7ff);
 353                 if ((*table & _REGION_ENTRY_INV) &&
 354                     gmap_alloc_table(gmap, table, _REGION3_ENTRY_EMPTY))
 355                         goto out_unmap;
 356                 table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
 357                 table = table + (((to + off) >> 31) & 0x7ff);
 358                 if ((*table & _REGION_ENTRY_INV) &&
 359                     gmap_alloc_table(gmap, table, _SEGMENT_ENTRY_EMPTY))
 360                         goto out_unmap;
 361                 table = (unsigned long *) (*table & _REGION_ENTRY_ORIGIN);
 362                 table = table + (((to + off) >> 20) & 0x7ff);
 363
 364                 /* Store 'from' address in an invalid segment table entry. */
 365                 flush |= gmap_unlink_segment(gmap, table);
 366                 *table = _SEGMENT_ENTRY_INV | _SEGMENT_ENTRY_RO | (from + off);
 367         }
 368         spin_unlock(&gmap->mm->page_table_lock);
 369         up_read(&gmap->mm->mmap_sem);
 370         if (flush)
 371                 gmap_flush_tlb(gmap);
 372         return 0;
 373
 374 out_unmap:
 375         spin_unlock(&gmap->mm->page_table_lock);
 376         up_read(&gmap->mm->mmap_sem);
 377         gmap_unmap_segment(gmap, to, len);
 378         return -ENOMEM;
 379 }
 380 EXPORT_SYMBOL_GPL(gmap_map_segment);
 381
 382 /*
 383  * this function is assumed to be called with mmap_sem held
 384  */
 385 unsigned long __gmap_fault(unsigned long address, struct gmap *gmap)
 386 {
 387         unsigned long *table, vmaddr, segment;
 388         struct mm_struct *mm;
 389         struct gmap_pgtable *mp;
 390         struct gmap_rmap *rmap;
 391         struct vm_area_struct *vma;
 392         struct page *page;
 393         pgd_t *pgd;
 394         pud_t *pud;
 395         pmd_t *pmd;
 396
 397         current->thread.gmap_addr = address;
 398         mm = gmap->mm;
 399         /* Walk the gmap address space page table */
 400         table = gmap->table + ((address >> 53) & 0x7ff);
 401         if (unlikely(*table & _REGION_ENTRY_INV))
 402                 return -EFAULT;
 403         table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
 404         table = table + ((address >> 42) & 0x7ff);
 405         if (unlikely(*table & _REGION_ENTRY_INV))
 406                 return -EFAULT;
 407         table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
 408         table = table + ((address >> 31) & 0x7ff);
 409         if (unlikely(*table & _REGION_ENTRY_INV))
 410                 return -EFAULT;
 411         table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
 412         table = table + ((address >> 20) & 0x7ff);
 413
 414         /* Convert the gmap address to an mm address. */
 415         segment = *table;
 416         if (likely(!(segment & _SEGMENT_ENTRY_INV))) {
 417                 page = pfn_to_page(segment >> PAGE_SHIFT);
 418                 mp = (struct gmap_pgtable *) page->index;
 419                 return mp->vmaddr | (address & ~PMD_MASK);
 420         } else if (segment & _SEGMENT_ENTRY_RO) {
 421                 vmaddr = segment & _SEGMENT_ENTRY_ORIGIN;
 422                 vma = find_vma(mm, vmaddr);
 423                 if (!vma || vma->vm_start > vmaddr)
 424                         return -EFAULT;
 425
 426                 /* Walk the parent mm page table */
 427                 pgd = pgd_offset(mm, vmaddr);
 428                 pud = pud_alloc(mm, pgd, vmaddr);
 429                 if (!pud)
 430                         return -ENOMEM;
 431                 pmd = pmd_alloc(mm, pud, vmaddr);
 432                 if (!pmd)
 433                         return -ENOMEM;
 434                 if (!pmd_present(*pmd) &&
 435                     __pte_alloc(mm, vma, pmd, vmaddr))
 436                         return -ENOMEM;
 437                 /* pmd now points to a valid segment table entry. */
 438                 rmap = kmalloc(sizeof(*rmap), GFP_KERNEL|__GFP_REPEAT);
 439                 if (!rmap)
 440                         return -ENOMEM;
 441                 /* Link gmap segment table entry location to page table. */
 442                 page = pmd_page(*pmd);
 443                 mp = (struct gmap_pgtable *) page->index;
 444                 rmap->entry = table;
 445                 spin_lock(&mm->page_table_lock);
 446                 list_add(&rmap->list, &mp->mapper);
 447                 spin_unlock(&mm->page_table_lock);
 448                 /* Set gmap segment table entry to page table. */
 449                 *table = pmd_val(*pmd) & PAGE_MASK;
 450                 return vmaddr | (address & ~PMD_MASK);
 451         }
 452         return -EFAULT;
 453 }
 454
 455 unsigned long gmap_fault(unsigned long address, struct gmap *gmap)
 456 {
 457         unsigned long rc;
 458
 459         down_read(&gmap->mm->mmap_sem);
 460         rc = __gmap_fault(address, gmap);
 461         up_read(&gmap->mm->mmap_sem);
 462
 463         return rc;
 464 }
 465 EXPORT_SYMBOL_GPL(gmap_fault);
 466
 467 void gmap_discard(unsigned long from, unsigned long to, struct gmap *gmap)
 468 {
 469
 470         unsigned long *table, address, size;
 471         struct vm_area_struct *vma;
 472         struct gmap_pgtable *mp;
 473         struct page *page;
 474
 475         down_read(&gmap->mm->mmap_sem);
 476         address = from;
 477         while (address < to) {
 478                 /* Walk the gmap address space page table */
 479                 table = gmap->table + ((address >> 53) & 0x7ff);
 480                 if (unlikely(*table & _REGION_ENTRY_INV)) {
 481                         address = (address + PMD_SIZE) & PMD_MASK;
 482                         continue;
 483                 }
 484                 table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
 485                 table = table + ((address >> 42) & 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 >> 31) & 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 >> 20) & 0x7ff);
 498                 if (unlikely(*table & _SEGMENT_ENTRY_INV)) {
 499                         address = (address + PMD_SIZE) & PMD_MASK;
 500                         continue;
 501                 }
 502                 page = pfn_to_page(*table >> PAGE_SHIFT);
 503                 mp = (struct gmap_pgtable *) page->index;
 504                 vma = find_vma(gmap->mm, mp->vmaddr);
 505                 size = min(to - address, PMD_SIZE - (address & ~PMD_MASK));
 506                 zap_page_range(vma, mp->vmaddr | (address & ~PMD_MASK),
 507                                size, NULL);
 508                 address = (address + PMD_SIZE) & PMD_MASK;
 509         }
 510         up_read(&gmap->mm->mmap_sem);
 511 }
 512 EXPORT_SYMBOL_GPL(gmap_discard);
 513
 514 void gmap_unmap_notifier(struct mm_struct *mm, unsigned long *table)
 515 {
 516         struct gmap_rmap *rmap, *next;
 517         struct gmap_pgtable *mp;
 518         struct page *page;
 519         int flush;
 520
 521         flush = 0;
 522         spin_lock(&mm->page_table_lock);
 523         page = pfn_to_page(__pa(table) >> PAGE_SHIFT);
 524         mp = (struct gmap_pgtable *) page->index;
 525         list_for_each_entry_safe(rmap, next, &mp->mapper, list) {
 526                 *rmap->entry =
 527                         _SEGMENT_ENTRY_INV | _SEGMENT_ENTRY_RO | mp->vmaddr;
 528                 list_del(&rmap->list);
 529                 kfree(rmap);
 530                 flush = 1;
 531         }
 532         spin_unlock(&mm->page_table_lock);
 533         if (flush)
 534                 __tlb_flush_global();
 535 }
 536
 537 static inline unsigned long *page_table_alloc_pgste(struct mm_struct *mm,
 538                                                     unsigned long vmaddr)
 539 {
 540         struct page *page;
 541         unsigned long *table;
 542         struct gmap_pgtable *mp;
 543
 544         page = alloc_page(GFP_KERNEL|__GFP_REPEAT);
 545         if (!page)
 546                 return NULL;
 547         mp = kmalloc(sizeof(*mp), GFP_KERNEL|__GFP_REPEAT);
 548         if (!mp) {
 549                 __free_page(page);
 550                 return NULL;
 551         }
 552         pgtable_page_ctor(page);
 553         mp->vmaddr = vmaddr & PMD_MASK;
 554         INIT_LIST_HEAD(&mp->mapper);
 555         page->index = (unsigned long) mp;
 556         atomic_set(&page->_mapcount, 3);
 557         table = (unsigned long *) page_to_phys(page);
 558         clear_table(table, _PAGE_TYPE_EMPTY, PAGE_SIZE/2);
 559         clear_table(table + PTRS_PER_PTE, 0, PAGE_SIZE/2);
 560         return table;
 561 }
 562
 563 static inline void page_table_free_pgste(unsigned long *table)
 564 {
 565         struct page *page;
 566         struct gmap_pgtable *mp;
 567
 568         page = pfn_to_page(__pa(table) >> PAGE_SHIFT);
 569         mp = (struct gmap_pgtable *) page->index;
 570         BUG_ON(!list_empty(&mp->mapper));
 571         pgtable_page_dtor(page);
 572         atomic_set(&page->_mapcount, -1);
 573         kfree(mp);
 574         __free_page(page);
 575 }
 576
 577 #else /* CONFIG_PGSTE */
 578
 579 static inline unsigned long *page_table_alloc_pgste(struct mm_struct *mm,
 580                                                     unsigned long vmaddr)
 581 {
 582         return NULL;
 583 }
 584
 585 static inline void page_table_free_pgste(unsigned long *table)
 586 {
 587 }
 588
 589 static inline void gmap_unmap_notifier(struct mm_struct *mm,
 590                                           unsigned long *table)
 591 {
 592 }
 593
 594 #endif /* CONFIG_PGSTE */
 595
 596 static inline unsigned int atomic_xor_bits(atomic_t *v, unsigned int bits)
 597 {
 598         unsigned int old, new;
 599
 600         do {
 601                 old = atomic_read(v);
 602                 new = old ^ bits;
 603         } while (atomic_cmpxchg(v, old, new) != old);
 604         return new;
 605 }
 606
 607 /*
 608  * page table entry allocation/free routines.
 609  */
 610 unsigned long *page_table_alloc(struct mm_struct *mm, unsigned long vmaddr)
 611 {
 612         unsigned long *uninitialized_var(table);
 613         struct page *uninitialized_var(page);
 614         unsigned int mask, bit;
 615
 616         if (mm_has_pgste(mm))
 617                 return page_table_alloc_pgste(mm, vmaddr);
 618         /* Allocate fragments of a 4K page as 1K/2K page table */
 619         spin_lock_bh(&mm->context.list_lock);
 620         mask = FRAG_MASK;
 621         if (!list_empty(&mm->context.pgtable_list)) {
 622                 page = list_first_entry(&mm->context.pgtable_list,
 623                                         struct page, lru);
 624                 table = (unsigned long *) page_to_phys(page);
 625                 mask = atomic_read(&page->_mapcount);
 626                 mask = mask | (mask >> 4);
 627         }
 628         if ((mask & FRAG_MASK) == FRAG_MASK) {
 629                 spin_unlock_bh(&mm->context.list_lock);
 630                 page = alloc_page(GFP_KERNEL|__GFP_REPEAT);
 631                 if (!page)
 632                         return NULL;
 633                 pgtable_page_ctor(page);
 634                 atomic_set(&page->_mapcount, 1);
 635                 table = (unsigned long *) page_to_phys(page);
 636                 clear_table(table, _PAGE_TYPE_EMPTY, PAGE_SIZE);
 637                 spin_lock_bh(&mm->context.list_lock);
 638                 list_add(&page->lru, &mm->context.pgtable_list);
 639         } else {
 640                 for (bit = 1; mask & bit; bit <<= 1)
 641                         table += PTRS_PER_PTE;
 642                 mask = atomic_xor_bits(&page->_mapcount, bit);
 643                 if ((mask & FRAG_MASK) == FRAG_MASK)
 644                         list_del(&page->lru);
 645         }
 646         spin_unlock_bh(&mm->context.list_lock);
 647         return table;
 648 }
 649
 650 void page_table_free(struct mm_struct *mm, unsigned long *table)
 651 {
 652         struct page *page;
 653         unsigned int bit, mask;
 654
 655         if (mm_has_pgste(mm)) {
 656                 gmap_unmap_notifier(mm, table);
 657                 return page_table_free_pgste(table);
 658         }
 659         /* Free 1K/2K page table fragment of a 4K page */
 660         page = pfn_to_page(__pa(table) >> PAGE_SHIFT);
 661         bit = 1 << ((__pa(table) & ~PAGE_MASK)/(PTRS_PER_PTE*sizeof(pte_t)));
 662         spin_lock_bh(&mm->context.list_lock);
 663         if ((atomic_read(&page->_mapcount) & FRAG_MASK) != FRAG_MASK)
 664                 list_del(&page->lru);
 665         mask = atomic_xor_bits(&page->_mapcount, bit);
 666         if (mask & FRAG_MASK)
 667                 list_add(&page->lru, &mm->context.pgtable_list);
 668         spin_unlock_bh(&mm->context.list_lock);
 669         if (mask == 0) {
 670                 pgtable_page_dtor(page);
 671                 atomic_set(&page->_mapcount, -1);
 672                 __free_page(page);
 673         }
 674 }
 675
 676 static void __page_table_free_rcu(void *table, unsigned bit)
 677 {
 678         struct page *page;
 679
 680         if (bit == FRAG_MASK)
 681                 return page_table_free_pgste(table);
 682         /* Free 1K/2K page table fragment of a 4K page */
 683         page = pfn_to_page(__pa(table) >> PAGE_SHIFT);
 684         if (atomic_xor_bits(&page->_mapcount, bit) == 0) {
 685                 pgtable_page_dtor(page);
 686                 atomic_set(&page->_mapcount, -1);
 687                 __free_page(page);
 688         }
 689 }
 690
 691 void page_table_free_rcu(struct mmu_gather *tlb, unsigned long *table)
 692 {
 693         struct mm_struct *mm;
 694         struct page *page;
 695         unsigned int bit, mask;
 696
 697         mm = tlb->mm;
 698         if (mm_has_pgste(mm)) {
 699                 gmap_unmap_notifier(mm, table);
 700                 table = (unsigned long *) (__pa(table) | FRAG_MASK);
 701                 tlb_remove_table(tlb, table);
 702                 return;
 703         }
 704         bit = 1 << ((__pa(table) & ~PAGE_MASK) / (PTRS_PER_PTE*sizeof(pte_t)));
 705         page = pfn_to_page(__pa(table) >> PAGE_SHIFT);
 706         spin_lock_bh(&mm->context.list_lock);
 707         if ((atomic_read(&page->_mapcount) & FRAG_MASK) != FRAG_MASK)
 708                 list_del(&page->lru);
 709         mask = atomic_xor_bits(&page->_mapcount, bit | (bit << 4));
 710         if (mask & FRAG_MASK)
 711                 list_add_tail(&page->lru, &mm->context.pgtable_list);
 712         spin_unlock_bh(&mm->context.list_lock);
 713         table = (unsigned long *) (__pa(table) | (bit << 4));
 714         tlb_remove_table(tlb, table);
 715 }
 716
 717 void __tlb_remove_table(void *_table)
 718 {
 719         const unsigned long mask = (FRAG_MASK << 4) | FRAG_MASK;
 720         void *table = (void *)((unsigned long) _table & ~mask);
 721         unsigned type = (unsigned long) _table & mask;
 722
 723         if (type)
 724                 __page_table_free_rcu(table, type);
 725         else
 726                 free_pages((unsigned long) table, ALLOC_ORDER);
 727 }
 728
 729 static void tlb_remove_table_smp_sync(void *arg)
 730 {
 731         /* Simply deliver the interrupt */
 732 }
 733
 734 static void tlb_remove_table_one(void *table)
 735 {
 736         /*
 737          * This isn't an RCU grace period and hence the page-tables cannot be
 738          * assumed to be actually RCU-freed.
 739          *
 740          * It is however sufficient for software page-table walkers that rely
 741          * on IRQ disabling. See the comment near struct mmu_table_batch.
 742          */
 743         smp_call_function(tlb_remove_table_smp_sync, NULL, 1);
 744         __tlb_remove_table(table);
 745 }
 746
 747 static void tlb_remove_table_rcu(struct rcu_head *head)
 748 {
 749         struct mmu_table_batch *batch;
 750         int i;
 751
 752         batch = container_of(head, struct mmu_table_batch, rcu);
 753
 754         for (i = 0; i < batch->nr; i++)
 755                 __tlb_remove_table(batch->tables[i]);
 756
 757         free_page((unsigned long)batch);
 758 }
 759
 760 void tlb_table_flush(struct mmu_gather *tlb)
 761 {
 762         struct mmu_table_batch **batch = &tlb->batch;
 763
 764         if (*batch) {
 765                 __tlb_flush_mm(tlb->mm);
 766                 call_rcu_sched(&(*batch)->rcu, tlb_remove_table_rcu);
 767                 *batch = NULL;
 768         }
 769 }
 770
 771 void tlb_remove_table(struct mmu_gather *tlb, void *table)
 772 {
 773         struct mmu_table_batch **batch = &tlb->batch;
 774
 775         if (*batch == NULL) {
 776                 *batch = (struct mmu_table_batch *)
 777                         __get_free_page(GFP_NOWAIT | __GFP_NOWARN);
 778                 if (*batch == NULL) {
 779                         __tlb_flush_mm(tlb->mm);
 780                         tlb_remove_table_one(table);
 781                         return;
 782                 }
 783                 (*batch)->nr = 0;
 784         }
 785         (*batch)->tables[(*batch)->nr++] = table;
 786         if ((*batch)->nr == MAX_TABLE_BATCH)
 787                 tlb_table_flush(tlb);
 788 }
 789
 790 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 791 void thp_split_vma(struct vm_area_struct *vma)
 792 {
 793         unsigned long addr;
 794         struct page *page;
 795
 796         for (addr = vma->vm_start; addr < vma->vm_end; addr += PAGE_SIZE) {
 797                 page = follow_page(vma, addr, FOLL_SPLIT);
 798         }
 799 }
 800
 801 void thp_split_mm(struct mm_struct *mm)
 802 {
 803         struct vm_area_struct *vma = mm->mmap;
 804
 805         while (vma != NULL) {
 806                 thp_split_vma(vma);
 807                 vma->vm_flags &= ~VM_HUGEPAGE;
 808                 vma->vm_flags |= VM_NOHUGEPAGE;
 809                 vma = vma->vm_next;
 810         }
 811 }
 812 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 813
 814 /*
 815  * switch on pgstes for its userspace process (for kvm)
 816  */
 817 int s390_enable_sie(void)
 818 {
 819         struct task_struct *tsk = current;
 820         struct mm_struct *mm, *old_mm;
 821
 822         /* Do we have switched amode? If no, we cannot do sie */
 823         if (s390_user_mode == HOME_SPACE_MODE)
 824                 return -EINVAL;
 825
 826         /* Do we have pgstes? if yes, we are done */
 827         if (mm_has_pgste(tsk->mm))
 828                 return 0;
 829
 830         /* lets check if we are allowed to replace the mm */
 831         task_lock(tsk);
 832         if (!tsk->mm || atomic_read(&tsk->mm->mm_users) > 1 ||
 833 #ifdef CONFIG_AIO
 834             !hlist_empty(&tsk->mm->ioctx_list) ||
 835 #endif
 836             tsk->mm != tsk->active_mm) {
 837                 task_unlock(tsk);
 838                 return -EINVAL;
 839         }
 840         task_unlock(tsk);
 841
 842         /* we copy the mm and let dup_mm create the page tables with_pgstes */
 843         tsk->mm->context.alloc_pgste = 1;
 844         /* make sure that both mms have a correct rss state */
 845         sync_mm_rss(tsk->mm);
 846         mm = dup_mm(tsk);
 847         tsk->mm->context.alloc_pgste = 0;
 848         if (!mm)
 849                 return -ENOMEM;
 850
 851 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 852         /* split thp mappings and disable thp for future mappings */
 853         thp_split_mm(mm);
 854         mm->def_flags |= VM_NOHUGEPAGE;
 855 #endif
 856
 857         /* Now lets check again if something happened */
 858         task_lock(tsk);
 859         if (!tsk->mm || atomic_read(&tsk->mm->mm_users) > 1 ||
 860 #ifdef CONFIG_AIO
 861             !hlist_empty(&tsk->mm->ioctx_list) ||
 862 #endif
 863             tsk->mm != tsk->active_mm) {
 864                 mmput(mm);
 865                 task_unlock(tsk);
 866                 return -EINVAL;
 867         }
 868
 869         /* ok, we are alone. No ptrace, no threads, etc. */
 870         old_mm = tsk->mm;
 871         tsk->mm = tsk->active_mm = mm;
 872         preempt_disable();
 873         update_mm(mm, tsk);
 874         atomic_inc(&mm->context.attach_count);
 875         atomic_dec(&old_mm->context.attach_count);
 876         cpumask_set_cpu(smp_processor_id(), mm_cpumask(mm));
 877         preempt_enable();
 878         task_unlock(tsk);
 879         mmput(old_mm);
 880         return 0;
 881 }
 882 EXPORT_SYMBOL_GPL(s390_enable_sie);
 883
 884 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 885 int pmdp_clear_flush_young(struct vm_area_struct *vma, unsigned long address,
 886                            pmd_t *pmdp)
 887 {
 888         VM_BUG_ON(address & ~HPAGE_PMD_MASK);
 889         /* No need to flush TLB
 890          * On s390 reference bits are in storage key and never in TLB */
 891         return pmdp_test_and_clear_young(vma, address, pmdp);
 892 }
 893
 894 int pmdp_set_access_flags(struct vm_area_struct *vma,
 895                           unsigned long address, pmd_t *pmdp,
 896                           pmd_t entry, int dirty)
 897 {
 898         VM_BUG_ON(address & ~HPAGE_PMD_MASK);
 899
 900         if (pmd_same(*pmdp, entry))
 901                 return 0;
 902         pmdp_invalidate(vma, address, pmdp);
 903         set_pmd_at(vma->vm_mm, address, pmdp, entry);
 904         return 1;
 905 }
 906
 907 static void pmdp_splitting_flush_sync(void *arg)
 908 {
 909         /* Simply deliver the interrupt */
 910 }
 911
 912 void pmdp_splitting_flush(struct vm_area_struct *vma, unsigned long address,
 913                           pmd_t *pmdp)
 914 {
 915         VM_BUG_ON(address & ~HPAGE_PMD_MASK);
 916         if (!test_and_set_bit(_SEGMENT_ENTRY_SPLIT_BIT,
 917                               (unsigned long *) pmdp)) {
 918                 /* need to serialize against gup-fast (IRQ disabled) */
 919                 smp_call_function(pmdp_splitting_flush_sync, NULL, 1);
 920         }
 921 }
 922
 923 void pgtable_trans_huge_deposit(struct mm_struct *mm, pgtable_t pgtable)
 924 {
 925         struct list_head *lh = (struct list_head *) pgtable;
 926
 927         assert_spin_locked(&mm->page_table_lock);
 928
 929         /* FIFO */
 930         if (!mm->pmd_huge_pte)
 931                 INIT_LIST_HEAD(lh);
 932         else
 933                 list_add(lh, (struct list_head *) mm->pmd_huge_pte);
 934         mm->pmd_huge_pte = pgtable;
 935 }
 936
 937 pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm)
 938 {
 939         struct list_head *lh;
 940         pgtable_t pgtable;
 941         pte_t *ptep;
 942
 943         assert_spin_locked(&mm->page_table_lock);
 944
 945         /* FIFO */
 946         pgtable = mm->pmd_huge_pte;
 947         lh = (struct list_head *) pgtable;
 948         if (list_empty(lh))
 949                 mm->pmd_huge_pte = NULL;
 950         else {
 951                 mm->pmd_huge_pte = (pgtable_t) lh->next;
 952                 list_del(lh);
 953         }
 954         ptep = (pte_t *) pgtable;
 955         pte_val(*ptep) = _PAGE_TYPE_EMPTY;
 956         ptep++;
 957         pte_val(*ptep) = _PAGE_TYPE_EMPTY;
 958         return pgtable;
 959 }
 960 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */