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/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         gmap->asce = _ASCE_TYPE_REGION1 | _ASCE_TABLE_LENGTH |
 164                      _ASCE_USER_BITS | __pa(table);
 165         list_add(&gmap->list, &mm->context.gmap_list);
 166         return gmap;
 167
 168 out_free:
 169         kfree(gmap);
 170 out:
 171         return NULL;
 172 }
 173 EXPORT_SYMBOL_GPL(gmap_alloc);
 174
 175 static int gmap_unlink_segment(struct gmap *gmap, unsigned long *table)
 176 {
 177         struct gmap_pgtable *mp;
 178         struct gmap_rmap *rmap;
 179         struct page *page;
 180
 181         if (*table & _SEGMENT_ENTRY_INV)
 182                 return 0;
 183         page = pfn_to_page(*table >> PAGE_SHIFT);
 184         mp = (struct gmap_pgtable *) page->index;
 185         list_for_each_entry(rmap, &mp->mapper, list) {
 186                 if (rmap->entry != table)
 187                         continue;
 188                 list_del(&rmap->list);
 189                 kfree(rmap);
 190                 break;
 191         }
 192         *table = _SEGMENT_ENTRY_INV | _SEGMENT_ENTRY_RO | mp->vmaddr;
 193         return 1;
 194 }
 195
 196 static void gmap_flush_tlb(struct gmap *gmap)
 197 {
 198         if (MACHINE_HAS_IDTE)
 199                 __tlb_flush_idte((unsigned long) gmap->table |
 200                                  _ASCE_TYPE_REGION1);
 201         else
 202                 __tlb_flush_global();
 203 }
 204
 205 /**
 206  * gmap_free - free a guest address space
 207  * @gmap: pointer to the guest address space structure
 208  */
 209 void gmap_free(struct gmap *gmap)
 210 {
 211         struct page *page, *next;
 212         unsigned long *table;
 213         int i;
 214
 215
 216         /* Flush tlb. */
 217         if (MACHINE_HAS_IDTE)
 218                 __tlb_flush_idte((unsigned long) gmap->table |
 219                                  _ASCE_TYPE_REGION1);
 220         else
 221                 __tlb_flush_global();
 222
 223         /* Free all segment & region tables. */
 224         down_read(&gmap->mm->mmap_sem);
 225         spin_lock(&gmap->mm->page_table_lock);
 226         list_for_each_entry_safe(page, next, &gmap->crst_list, lru) {
 227                 table = (unsigned long *) page_to_phys(page);
 228                 if ((*table & _REGION_ENTRY_TYPE_MASK) == 0)
 229                         /* Remove gmap rmap structures for segment table. */
 230                         for (i = 0; i < PTRS_PER_PMD; i++, table++)
 231                                 gmap_unlink_segment(gmap, table);
 232                 __free_pages(page, ALLOC_ORDER);
 233         }
 234         spin_unlock(&gmap->mm->page_table_lock);
 235         up_read(&gmap->mm->mmap_sem);
 236         list_del(&gmap->list);
 237         kfree(gmap);
 238 }
 239 EXPORT_SYMBOL_GPL(gmap_free);
 240
 241 /**
 242  * gmap_enable - switch primary space to the guest address space
 243  * @gmap: pointer to the guest address space structure
 244  */
 245 void gmap_enable(struct gmap *gmap)
 246 {
 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         S390_lowcore.gmap = 0UL;
 258 }
 259 EXPORT_SYMBOL_GPL(gmap_disable);
 260
 261 /*
 262  * gmap_alloc_table is assumed to be called with mmap_sem held
 263  */
 264 static int gmap_alloc_table(struct gmap *gmap,
 265                                unsigned long *table, unsigned long init)
 266 {
 267         struct page *page;
 268         unsigned long *new;
 269
 270         page = alloc_pages(GFP_KERNEL, ALLOC_ORDER);
 271         if (!page)
 272                 return -ENOMEM;
 273         new = (unsigned long *) page_to_phys(page);
 274         crst_table_init(new, init);
 275         if (*table & _REGION_ENTRY_INV) {
 276                 list_add(&page->lru, &gmap->crst_list);
 277                 *table = (unsigned long) new | _REGION_ENTRY_LENGTH |
 278                         (*table & _REGION_ENTRY_TYPE_MASK);
 279         } else
 280                 __free_pages(page, ALLOC_ORDER);
 281         return 0;
 282 }
 283
 284 /**
 285  * gmap_unmap_segment - unmap segment from the guest address space
 286  * @gmap: pointer to the guest address space structure
 287  * @addr: address in the guest address space
 288  * @len: length of the memory area to unmap
 289  *
 290  * Returns 0 if the unmap succeded, -EINVAL if not.
 291  */
 292 int gmap_unmap_segment(struct gmap *gmap, unsigned long to, unsigned long len)
 293 {
 294         unsigned long *table;
 295         unsigned long off;
 296         int flush;
 297
 298         if ((to | len) & (PMD_SIZE - 1))
 299                 return -EINVAL;
 300         if (len == 0 || to + len < to)
 301                 return -EINVAL;
 302
 303         flush = 0;
 304         down_read(&gmap->mm->mmap_sem);
 305         spin_lock(&gmap->mm->page_table_lock);
 306         for (off = 0; off < len; off += PMD_SIZE) {
 307                 /* Walk the guest addr space page table */
 308                 table = gmap->table + (((to + off) >> 53) & 0x7ff);
 309                 if (*table & _REGION_ENTRY_INV)
 310                         goto out;
 311                 table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
 312                 table = table + (((to + off) >> 42) & 0x7ff);
 313                 if (*table & _REGION_ENTRY_INV)
 314                         goto out;
 315                 table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
 316                 table = table + (((to + off) >> 31) & 0x7ff);
 317                 if (*table & _REGION_ENTRY_INV)
 318                         goto out;
 319                 table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
 320                 table = table + (((to + off) >> 20) & 0x7ff);
 321
 322                 /* Clear segment table entry in guest address space. */
 323                 flush |= gmap_unlink_segment(gmap, table);
 324                 *table = _SEGMENT_ENTRY_INV;
 325         }
 326 out:
 327         spin_unlock(&gmap->mm->page_table_lock);
 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         spin_lock(&gmap->mm->page_table_lock);
 359         for (off = 0; off < len; off += PMD_SIZE) {
 360                 /* Walk the gmap address space page table */
 361                 table = gmap->table + (((to + off) >> 53) & 0x7ff);
 362                 if ((*table & _REGION_ENTRY_INV) &&
 363                     gmap_alloc_table(gmap, table, _REGION2_ENTRY_EMPTY))
 364                         goto out_unmap;
 365                 table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
 366                 table = table + (((to + off) >> 42) & 0x7ff);
 367                 if ((*table & _REGION_ENTRY_INV) &&
 368                     gmap_alloc_table(gmap, table, _REGION3_ENTRY_EMPTY))
 369                         goto out_unmap;
 370                 table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
 371                 table = table + (((to + off) >> 31) & 0x7ff);
 372                 if ((*table & _REGION_ENTRY_INV) &&
 373                     gmap_alloc_table(gmap, table, _SEGMENT_ENTRY_EMPTY))
 374                         goto out_unmap;
 375                 table = (unsigned long *) (*table & _REGION_ENTRY_ORIGIN);
 376                 table = table + (((to + off) >> 20) & 0x7ff);
 377
 378                 /* Store 'from' address in an invalid segment table entry. */
 379                 flush |= gmap_unlink_segment(gmap, table);
 380                 *table = _SEGMENT_ENTRY_INV | _SEGMENT_ENTRY_RO | (from + off);
 381         }
 382         spin_unlock(&gmap->mm->page_table_lock);
 383         up_read(&gmap->mm->mmap_sem);
 384         if (flush)
 385                 gmap_flush_tlb(gmap);
 386         return 0;
 387
 388 out_unmap:
 389         spin_unlock(&gmap->mm->page_table_lock);
 390         up_read(&gmap->mm->mmap_sem);
 391         gmap_unmap_segment(gmap, to, len);
 392         return -ENOMEM;
 393 }
 394 EXPORT_SYMBOL_GPL(gmap_map_segment);
 395
 396 /*
 397  * this function is assumed to be called with mmap_sem held
 398  */
 399 unsigned long __gmap_fault(unsigned long address, struct gmap *gmap)
 400 {
 401         unsigned long *table, vmaddr, segment;
 402         struct mm_struct *mm;
 403         struct gmap_pgtable *mp;
 404         struct gmap_rmap *rmap;
 405         struct vm_area_struct *vma;
 406         struct page *page;
 407         pgd_t *pgd;
 408         pud_t *pud;
 409         pmd_t *pmd;
 410
 411         current->thread.gmap_addr = address;
 412         mm = gmap->mm;
 413         /* Walk the gmap address space page table */
 414         table = gmap->table + ((address >> 53) & 0x7ff);
 415         if (unlikely(*table & _REGION_ENTRY_INV))
 416                 return -EFAULT;
 417         table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
 418         table = table + ((address >> 42) & 0x7ff);
 419         if (unlikely(*table & _REGION_ENTRY_INV))
 420                 return -EFAULT;
 421         table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
 422         table = table + ((address >> 31) & 0x7ff);
 423         if (unlikely(*table & _REGION_ENTRY_INV))
 424                 return -EFAULT;
 425         table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
 426         table = table + ((address >> 20) & 0x7ff);
 427
 428         /* Convert the gmap address to an mm address. */
 429         segment = *table;
 430         if (likely(!(segment & _SEGMENT_ENTRY_INV))) {
 431                 page = pfn_to_page(segment >> PAGE_SHIFT);
 432                 mp = (struct gmap_pgtable *) page->index;
 433                 return mp->vmaddr | (address & ~PMD_MASK);
 434         } else if (segment & _SEGMENT_ENTRY_RO) {
 435                 vmaddr = segment & _SEGMENT_ENTRY_ORIGIN;
 436                 vma = find_vma(mm, vmaddr);
 437                 if (!vma || vma->vm_start > vmaddr)
 438                         return -EFAULT;
 439
 440                 /* Walk the parent mm page table */
 441                 pgd = pgd_offset(mm, vmaddr);
 442                 pud = pud_alloc(mm, pgd, vmaddr);
 443                 if (!pud)
 444                         return -ENOMEM;
 445                 pmd = pmd_alloc(mm, pud, vmaddr);
 446                 if (!pmd)
 447                         return -ENOMEM;
 448                 if (!pmd_present(*pmd) &&
 449                     __pte_alloc(mm, vma, pmd, vmaddr))
 450                         return -ENOMEM;
 451                 /* pmd now points to a valid segment table entry. */
 452                 rmap = kmalloc(sizeof(*rmap), GFP_KERNEL|__GFP_REPEAT);
 453                 if (!rmap)
 454                         return -ENOMEM;
 455                 /* Link gmap segment table entry location to page table. */
 456                 page = pmd_page(*pmd);
 457                 mp = (struct gmap_pgtable *) page->index;
 458                 rmap->entry = table;
 459                 spin_lock(&mm->page_table_lock);
 460                 list_add(&rmap->list, &mp->mapper);
 461                 spin_unlock(&mm->page_table_lock);
 462                 /* Set gmap segment table entry to page table. */
 463                 *table = pmd_val(*pmd) & PAGE_MASK;
 464                 return vmaddr | (address & ~PMD_MASK);
 465         }
 466         return -EFAULT;
 467 }
 468
 469 unsigned long gmap_fault(unsigned long address, struct gmap *gmap)
 470 {
 471         unsigned long rc;
 472
 473         down_read(&gmap->mm->mmap_sem);
 474         rc = __gmap_fault(address, gmap);
 475         up_read(&gmap->mm->mmap_sem);
 476
 477         return rc;
 478 }
 479 EXPORT_SYMBOL_GPL(gmap_fault);
 480
 481 void gmap_discard(unsigned long from, unsigned long to, struct gmap *gmap)
 482 {
 483
 484         unsigned long *table, address, size;
 485         struct vm_area_struct *vma;
 486         struct gmap_pgtable *mp;
 487         struct page *page;
 488
 489         down_read(&gmap->mm->mmap_sem);
 490         address = from;
 491         while (address < to) {
 492                 /* Walk the gmap address space page table */
 493                 table = gmap->table + ((address >> 53) & 0x7ff);
 494                 if (unlikely(*table & _REGION_ENTRY_INV)) {
 495                         address = (address + PMD_SIZE) & PMD_MASK;
 496                         continue;
 497                 }
 498                 table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
 499                 table = table + ((address >> 42) & 0x7ff);
 500                 if (unlikely(*table & _REGION_ENTRY_INV)) {
 501                         address = (address + PMD_SIZE) & PMD_MASK;
 502                         continue;
 503                 }
 504                 table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
 505                 table = table + ((address >> 31) & 0x7ff);
 506                 if (unlikely(*table & _REGION_ENTRY_INV)) {
 507                         address = (address + PMD_SIZE) & PMD_MASK;
 508                         continue;
 509                 }
 510                 table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
 511                 table = table + ((address >> 20) & 0x7ff);
 512                 if (unlikely(*table & _SEGMENT_ENTRY_INV)) {
 513                         address = (address + PMD_SIZE) & PMD_MASK;
 514                         continue;
 515                 }
 516                 page = pfn_to_page(*table >> PAGE_SHIFT);
 517                 mp = (struct gmap_pgtable *) page->index;
 518                 vma = find_vma(gmap->mm, mp->vmaddr);
 519                 size = min(to - address, PMD_SIZE - (address & ~PMD_MASK));
 520                 zap_page_range(vma, mp->vmaddr | (address & ~PMD_MASK),
 521                                size, NULL);
 522                 address = (address + PMD_SIZE) & PMD_MASK;
 523         }
 524         up_read(&gmap->mm->mmap_sem);
 525 }
 526 EXPORT_SYMBOL_GPL(gmap_discard);
 527
 528 void gmap_unmap_notifier(struct mm_struct *mm, unsigned long *table)
 529 {
 530         struct gmap_rmap *rmap, *next;
 531         struct gmap_pgtable *mp;
 532         struct page *page;
 533         int flush;
 534
 535         flush = 0;
 536         spin_lock(&mm->page_table_lock);
 537         page = pfn_to_page(__pa(table) >> PAGE_SHIFT);
 538         mp = (struct gmap_pgtable *) page->index;
 539         list_for_each_entry_safe(rmap, next, &mp->mapper, list) {
 540                 *rmap->entry =
 541                         _SEGMENT_ENTRY_INV | _SEGMENT_ENTRY_RO | mp->vmaddr;
 542                 list_del(&rmap->list);
 543                 kfree(rmap);
 544                 flush = 1;
 545         }
 546         spin_unlock(&mm->page_table_lock);
 547         if (flush)
 548                 __tlb_flush_global();
 549 }
 550
 551 static inline unsigned long *page_table_alloc_pgste(struct mm_struct *mm,
 552                                                     unsigned long vmaddr)
 553 {
 554         struct page *page;
 555         unsigned long *table;
 556         struct gmap_pgtable *mp;
 557
 558         page = alloc_page(GFP_KERNEL|__GFP_REPEAT);
 559         if (!page)
 560                 return NULL;
 561         mp = kmalloc(sizeof(*mp), GFP_KERNEL|__GFP_REPEAT);
 562         if (!mp) {
 563                 __free_page(page);
 564                 return NULL;
 565         }
 566         pgtable_page_ctor(page);
 567         mp->vmaddr = vmaddr & PMD_MASK;
 568         INIT_LIST_HEAD(&mp->mapper);
 569         page->index = (unsigned long) mp;
 570         atomic_set(&page->_mapcount, 3);
 571         table = (unsigned long *) page_to_phys(page);
 572         clear_table(table, _PAGE_TYPE_EMPTY, PAGE_SIZE/2);
 573         clear_table(table + PTRS_PER_PTE, 0, PAGE_SIZE/2);
 574         return table;
 575 }
 576
 577 static inline void page_table_free_pgste(unsigned long *table)
 578 {
 579         struct page *page;
 580         struct gmap_pgtable *mp;
 581
 582         page = pfn_to_page(__pa(table) >> PAGE_SHIFT);
 583         mp = (struct gmap_pgtable *) page->index;
 584         BUG_ON(!list_empty(&mp->mapper));
 585         pgtable_page_ctor(page);
 586         atomic_set(&page->_mapcount, -1);
 587         kfree(mp);
 588         __free_page(page);
 589 }
 590
 591 #else /* CONFIG_PGSTE */
 592
 593 static inline unsigned long *page_table_alloc_pgste(struct mm_struct *mm,
 594                                                     unsigned long vmaddr)
 595 {
 596         return NULL;
 597 }
 598
 599 static inline void page_table_free_pgste(unsigned long *table)
 600 {
 601 }
 602
 603 static inline void gmap_unmap_notifier(struct mm_struct *mm,
 604                                           unsigned long *table)
 605 {
 606 }
 607
 608 #endif /* CONFIG_PGSTE */
 609
 610 static inline unsigned int atomic_xor_bits(atomic_t *v, unsigned int bits)
 611 {
 612         unsigned int old, new;
 613
 614         do {
 615                 old = atomic_read(v);
 616                 new = old ^ bits;
 617         } while (atomic_cmpxchg(v, old, new) != old);
 618         return new;
 619 }
 620
 621 /*
 622  * page table entry allocation/free routines.
 623  */
 624 unsigned long *page_table_alloc(struct mm_struct *mm, unsigned long vmaddr)
 625 {
 626         struct page *page;
 627         unsigned long *table;
 628         unsigned int mask, bit;
 629
 630         if (mm_has_pgste(mm))
 631                 return page_table_alloc_pgste(mm, vmaddr);
 632         /* Allocate fragments of a 4K page as 1K/2K page table */
 633         spin_lock_bh(&mm->context.list_lock);
 634         mask = FRAG_MASK;
 635         if (!list_empty(&mm->context.pgtable_list)) {
 636                 page = list_first_entry(&mm->context.pgtable_list,
 637                                         struct page, lru);
 638                 table = (unsigned long *) page_to_phys(page);
 639                 mask = atomic_read(&page->_mapcount);
 640                 mask = mask | (mask >> 4);
 641         }
 642         if ((mask & FRAG_MASK) == FRAG_MASK) {
 643                 spin_unlock_bh(&mm->context.list_lock);
 644                 page = alloc_page(GFP_KERNEL|__GFP_REPEAT);
 645                 if (!page)
 646                         return NULL;
 647                 pgtable_page_ctor(page);
 648                 atomic_set(&page->_mapcount, 1);
 649                 table = (unsigned long *) page_to_phys(page);
 650                 clear_table(table, _PAGE_TYPE_EMPTY, PAGE_SIZE);
 651                 spin_lock_bh(&mm->context.list_lock);
 652                 list_add(&page->lru, &mm->context.pgtable_list);
 653         } else {
 654                 for (bit = 1; mask & bit; bit <<= 1)
 655                         table += PTRS_PER_PTE;
 656                 mask = atomic_xor_bits(&page->_mapcount, bit);
 657                 if ((mask & FRAG_MASK) == FRAG_MASK)
 658                         list_del(&page->lru);
 659         }
 660         spin_unlock_bh(&mm->context.list_lock);
 661         return table;
 662 }
 663
 664 void page_table_free(struct mm_struct *mm, unsigned long *table)
 665 {
 666         struct page *page;
 667         unsigned int bit, mask;
 668
 669         if (mm_has_pgste(mm)) {
 670                 gmap_unmap_notifier(mm, table);
 671                 return page_table_free_pgste(table);
 672         }
 673         /* Free 1K/2K page table fragment of a 4K page */
 674         page = pfn_to_page(__pa(table) >> PAGE_SHIFT);
 675         bit = 1 << ((__pa(table) & ~PAGE_MASK)/(PTRS_PER_PTE*sizeof(pte_t)));
 676         spin_lock_bh(&mm->context.list_lock);
 677         if ((atomic_read(&page->_mapcount) & FRAG_MASK) != FRAG_MASK)
 678                 list_del(&page->lru);
 679         mask = atomic_xor_bits(&page->_mapcount, bit);
 680         if (mask & FRAG_MASK)
 681                 list_add(&page->lru, &mm->context.pgtable_list);
 682         spin_unlock_bh(&mm->context.list_lock);
 683         if (mask == 0) {
 684                 pgtable_page_dtor(page);
 685                 atomic_set(&page->_mapcount, -1);
 686                 __free_page(page);
 687         }
 688 }
 689
 690 #ifdef CONFIG_HAVE_RCU_TABLE_FREE
 691
 692 static void __page_table_free_rcu(void *table, unsigned bit)
 693 {
 694         struct page *page;
 695
 696         if (bit == FRAG_MASK)
 697                 return page_table_free_pgste(table);
 698         /* Free 1K/2K page table fragment of a 4K page */
 699         page = pfn_to_page(__pa(table) >> PAGE_SHIFT);
 700         if (atomic_xor_bits(&page->_mapcount, bit) == 0) {
 701                 pgtable_page_dtor(page);
 702                 atomic_set(&page->_mapcount, -1);
 703                 __free_page(page);
 704         }
 705 }
 706
 707 void page_table_free_rcu(struct mmu_gather *tlb, unsigned long *table)
 708 {
 709         struct mm_struct *mm;
 710         struct page *page;
 711         unsigned int bit, mask;
 712
 713         mm = tlb->mm;
 714         if (mm_has_pgste(mm)) {
 715                 gmap_unmap_notifier(mm, table);
 716                 table = (unsigned long *) (__pa(table) | FRAG_MASK);
 717                 tlb_remove_table(tlb, table);
 718                 return;
 719         }
 720         bit = 1 << ((__pa(table) & ~PAGE_MASK) / (PTRS_PER_PTE*sizeof(pte_t)));
 721         page = pfn_to_page(__pa(table) >> PAGE_SHIFT);
 722         spin_lock_bh(&mm->context.list_lock);
 723         if ((atomic_read(&page->_mapcount) & FRAG_MASK) != FRAG_MASK)
 724                 list_del(&page->lru);
 725         mask = atomic_xor_bits(&page->_mapcount, bit | (bit << 4));
 726         if (mask & FRAG_MASK)
 727                 list_add_tail(&page->lru, &mm->context.pgtable_list);
 728         spin_unlock_bh(&mm->context.list_lock);
 729         table = (unsigned long *) (__pa(table) | (bit << 4));
 730         tlb_remove_table(tlb, table);
 731 }
 732
 733 void __tlb_remove_table(void *_table)
 734 {
 735         const unsigned long mask = (FRAG_MASK << 4) | FRAG_MASK;
 736         void *table = (void *)((unsigned long) _table & ~mask);
 737         unsigned type = (unsigned long) _table & mask;
 738
 739         if (type)
 740                 __page_table_free_rcu(table, type);
 741         else
 742                 free_pages((unsigned long) table, ALLOC_ORDER);
 743 }
 744
 745 #endif
 746
 747 /*
 748  * switch on pgstes for its userspace process (for kvm)
 749  */
 750 int s390_enable_sie(void)
 751 {
 752         struct task_struct *tsk = current;
 753         struct mm_struct *mm, *old_mm;
 754
 755         /* Do we have switched amode? If no, we cannot do sie */
 756         if (user_mode == HOME_SPACE_MODE)
 757                 return -EINVAL;
 758
 759         /* Do we have pgstes? if yes, we are done */
 760         if (mm_has_pgste(tsk->mm))
 761                 return 0;
 762
 763         /* lets check if we are allowed to replace the mm */
 764         task_lock(tsk);
 765         if (!tsk->mm || atomic_read(&tsk->mm->mm_users) > 1 ||
 766 #ifdef CONFIG_AIO
 767             !hlist_empty(&tsk->mm->ioctx_list) ||
 768 #endif
 769             tsk->mm != tsk->active_mm) {
 770                 task_unlock(tsk);
 771                 return -EINVAL;
 772         }
 773         task_unlock(tsk);
 774
 775         /* we copy the mm and let dup_mm create the page tables with_pgstes */
 776         tsk->mm->context.alloc_pgste = 1;
 777         mm = dup_mm(tsk);
 778         tsk->mm->context.alloc_pgste = 0;
 779         if (!mm)
 780                 return -ENOMEM;
 781
 782         /* Now lets check again if something happened */
 783         task_lock(tsk);
 784         if (!tsk->mm || atomic_read(&tsk->mm->mm_users) > 1 ||
 785 #ifdef CONFIG_AIO
 786             !hlist_empty(&tsk->mm->ioctx_list) ||
 787 #endif
 788             tsk->mm != tsk->active_mm) {
 789                 mmput(mm);
 790                 task_unlock(tsk);
 791                 return -EINVAL;
 792         }
 793
 794         /* ok, we are alone. No ptrace, no threads, etc. */
 795         old_mm = tsk->mm;
 796         tsk->mm = tsk->active_mm = mm;
 797         preempt_disable();
 798         update_mm(mm, tsk);
 799         atomic_inc(&mm->context.attach_count);
 800         atomic_dec(&old_mm->context.attach_count);
 801         cpumask_set_cpu(smp_processor_id(), mm_cpumask(mm));
 802         preempt_enable();
 803         task_unlock(tsk);
 804         mmput(old_mm);
 805         return 0;
 806 }
 807 EXPORT_SYMBOL_GPL(s390_enable_sie);
 808
 809 #if defined(CONFIG_DEBUG_PAGEALLOC) && defined(CONFIG_HIBERNATION)
 810 bool kernel_page_present(struct page *page)
 811 {
 812         unsigned long addr;
 813         int cc;
 814
 815         addr = page_to_phys(page);
 816         asm volatile(
 817                 "       lra     %1,0(%1)\n"
 818                 "       ipm     %0\n"
 819                 "       srl     %0,28"
 820                 : "=d" (cc), "+a" (addr) : : "cc");
 821         return cc == 0;
 822 }
 823 #endif /* CONFIG_HIBERNATION && CONFIG_DEBUG_PAGEALLOC */