arch/sparc/mm/hugetlbpage.c

   1 /*
   2  * SPARC64 Huge TLB page support.
   3  *
   4  * Copyright (C) 2002, 2003, 2006 David S. Miller (davem@davemloft.net)
   5  */
   6
   7 #include <linux/fs.h>
   8 #include <linux/mm.h>
   9 #include <linux/sched/mm.h>
  10 #include <linux/hugetlb.h>
  11 #include <linux/pagemap.h>
  12 #include <linux/sysctl.h>
  13
  14 #include <asm/mman.h>
  15 #include <asm/pgalloc.h>
  16 #include <asm/pgtable.h>
  17 #include <asm/tlb.h>
  18 #include <asm/tlbflush.h>
  19 #include <asm/cacheflush.h>
  20 #include <asm/mmu_context.h>
  21
  22 /* Slightly simplified from the non-hugepage variant because by
  23  * definition we don't have to worry about any page coloring stuff
  24  */
  25
  26 static unsigned long hugetlb_get_unmapped_area_bottomup(struct file *filp,
  27                                                         unsigned long addr,
  28                                                         unsigned long len,
  29                                                         unsigned long pgoff,
  30                                                         unsigned long flags)
  31 {
  32         struct hstate *h = hstate_file(filp);
  33         unsigned long task_size = TASK_SIZE;
  34         struct vm_unmapped_area_info info;
  35
  36         if (test_thread_flag(TIF_32BIT))
  37                 task_size = STACK_TOP32;
  38
  39         info.flags = 0;
  40         info.length = len;
  41         info.low_limit = TASK_UNMAPPED_BASE;
  42         info.high_limit = min(task_size, VA_EXCLUDE_START);
  43         info.align_mask = PAGE_MASK & ~huge_page_mask(h);
  44         info.align_offset = 0;
  45         addr = vm_unmapped_area(&info);
  46
  47         if ((addr & ~PAGE_MASK) && task_size > VA_EXCLUDE_END) {
  48                 VM_BUG_ON(addr != -ENOMEM);
  49                 info.low_limit = VA_EXCLUDE_END;
  50                 info.high_limit = task_size;
  51                 addr = vm_unmapped_area(&info);
  52         }
  53
  54         return addr;
  55 }
  56
  57 static unsigned long
  58 hugetlb_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
  59                                   const unsigned long len,
  60                                   const unsigned long pgoff,
  61                                   const unsigned long flags)
  62 {
  63         struct hstate *h = hstate_file(filp);
  64         struct mm_struct *mm = current->mm;
  65         unsigned long addr = addr0;
  66         struct vm_unmapped_area_info info;
  67
  68         /* This should only ever run for 32-bit processes.  */
  69         BUG_ON(!test_thread_flag(TIF_32BIT));
  70
  71         info.flags = VM_UNMAPPED_AREA_TOPDOWN;
  72         info.length = len;
  73         info.low_limit = PAGE_SIZE;
  74         info.high_limit = mm->mmap_base;
  75         info.align_mask = PAGE_MASK & ~huge_page_mask(h);
  76         info.align_offset = 0;
  77         addr = vm_unmapped_area(&info);
  78
  79         /*
  80          * A failed mmap() very likely causes application failure,
  81          * so fall back to the bottom-up function here. This scenario
  82          * can happen with large stack limits and large mmap()
  83          * allocations.
  84          */
  85         if (addr & ~PAGE_MASK) {
  86                 VM_BUG_ON(addr != -ENOMEM);
  87                 info.flags = 0;
  88                 info.low_limit = TASK_UNMAPPED_BASE;
  89                 info.high_limit = STACK_TOP32;
  90                 addr = vm_unmapped_area(&info);
  91         }
  92
  93         return addr;
  94 }
  95
  96 unsigned long
  97 hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
  98                 unsigned long len, unsigned long pgoff, unsigned long flags)
  99 {
 100         struct hstate *h = hstate_file(file);
 101         struct mm_struct *mm = current->mm;
 102         struct vm_area_struct *vma;
 103         unsigned long task_size = TASK_SIZE;
 104
 105         if (test_thread_flag(TIF_32BIT))
 106                 task_size = STACK_TOP32;
 107
 108         if (len & ~huge_page_mask(h))
 109                 return -EINVAL;
 110         if (len > task_size)
 111                 return -ENOMEM;
 112
 113         if (flags & MAP_FIXED) {
 114                 if (prepare_hugepage_range(file, addr, len))
 115                         return -EINVAL;
 116                 return addr;
 117         }
 118
 119         if (addr) {
 120                 addr = ALIGN(addr, huge_page_size(h));
 121                 vma = find_vma(mm, addr);
 122                 if (task_size - len >= addr &&
 123                     (!vma || addr + len <= vma->vm_start))
 124                         return addr;
 125         }
 126         if (mm->get_unmapped_area == arch_get_unmapped_area)
 127                 return hugetlb_get_unmapped_area_bottomup(file, addr, len,
 128                                 pgoff, flags);
 129         else
 130                 return hugetlb_get_unmapped_area_topdown(file, addr, len,
 131                                 pgoff, flags);
 132 }
 133
 134 static pte_t sun4u_hugepage_shift_to_tte(pte_t entry, unsigned int shift)
 135 {
 136         return entry;
 137 }
 138
 139 static pte_t sun4v_hugepage_shift_to_tte(pte_t entry, unsigned int shift)
 140 {
 141         unsigned long hugepage_size = _PAGE_SZ4MB_4V;
 142
 143         pte_val(entry) = pte_val(entry) & ~_PAGE_SZALL_4V;
 144
 145         switch (shift) {
 146         case HPAGE_2GB_SHIFT:
 147                 hugepage_size = _PAGE_SZ2GB_4V;
 148                 pte_val(entry) |= _PAGE_PMD_HUGE;
 149                 break;
 150         case HPAGE_256MB_SHIFT:
 151                 hugepage_size = _PAGE_SZ256MB_4V;
 152                 pte_val(entry) |= _PAGE_PMD_HUGE;
 153                 break;
 154         case HPAGE_SHIFT:
 155                 pte_val(entry) |= _PAGE_PMD_HUGE;
 156                 break;
 157         case HPAGE_64K_SHIFT:
 158                 hugepage_size = _PAGE_SZ64K_4V;
 159                 break;
 160         default:
 161                 WARN_ONCE(1, "unsupported hugepage shift=%u\n", shift);
 162         }
 163
 164         pte_val(entry) = pte_val(entry) | hugepage_size;
 165         return entry;
 166 }
 167
 168 static pte_t hugepage_shift_to_tte(pte_t entry, unsigned int shift)
 169 {
 170         if (tlb_type == hypervisor)
 171                 return sun4v_hugepage_shift_to_tte(entry, shift);
 172         else
 173                 return sun4u_hugepage_shift_to_tte(entry, shift);
 174 }
 175
 176 pte_t arch_make_huge_pte(pte_t entry, struct vm_area_struct *vma,
 177                          struct page *page, int writeable)
 178 {
 179         unsigned int shift = huge_page_shift(hstate_vma(vma));
 180
 181         return hugepage_shift_to_tte(entry, shift);
 182 }
 183
 184 static unsigned int sun4v_huge_tte_to_shift(pte_t entry)
 185 {
 186         unsigned long tte_szbits = pte_val(entry) & _PAGE_SZALL_4V;
 187         unsigned int shift;
 188
 189         switch (tte_szbits) {
 190         case _PAGE_SZ2GB_4V:
 191                 shift = HPAGE_2GB_SHIFT;
 192                 break;
 193         case _PAGE_SZ256MB_4V:
 194                 shift = HPAGE_256MB_SHIFT;
 195                 break;
 196         case _PAGE_SZ4MB_4V:
 197                 shift = REAL_HPAGE_SHIFT;
 198                 break;
 199         case _PAGE_SZ64K_4V:
 200                 shift = HPAGE_64K_SHIFT;
 201                 break;
 202         default:
 203                 shift = PAGE_SHIFT;
 204                 break;
 205         }
 206         return shift;
 207 }
 208
 209 static unsigned int sun4u_huge_tte_to_shift(pte_t entry)
 210 {
 211         unsigned long tte_szbits = pte_val(entry) & _PAGE_SZALL_4U;
 212         unsigned int shift;
 213
 214         switch (tte_szbits) {
 215         case _PAGE_SZ256MB_4U:
 216                 shift = HPAGE_256MB_SHIFT;
 217                 break;
 218         case _PAGE_SZ4MB_4U:
 219                 shift = REAL_HPAGE_SHIFT;
 220                 break;
 221         case _PAGE_SZ64K_4U:
 222                 shift = HPAGE_64K_SHIFT;
 223                 break;
 224         default:
 225                 shift = PAGE_SHIFT;
 226                 break;
 227         }
 228         return shift;
 229 }
 230
 231 static unsigned int huge_tte_to_shift(pte_t entry)
 232 {
 233         unsigned long shift;
 234
 235         if (tlb_type == hypervisor)
 236                 shift = sun4v_huge_tte_to_shift(entry);
 237         else
 238                 shift = sun4u_huge_tte_to_shift(entry);
 239
 240         if (shift == PAGE_SHIFT)
 241                 WARN_ONCE(1, "tto_to_shift: invalid hugepage tte=0x%lx\n",
 242                           pte_val(entry));
 243
 244         return shift;
 245 }
 246
 247 static unsigned long huge_tte_to_size(pte_t pte)
 248 {
 249         unsigned long size = 1UL << huge_tte_to_shift(pte);
 250
 251         if (size == REAL_HPAGE_SIZE)
 252                 size = HPAGE_SIZE;
 253         return size;
 254 }
 255
 256 pte_t *huge_pte_alloc(struct mm_struct *mm,
 257                         unsigned long addr, unsigned long sz)
 258 {
 259         pgd_t *pgd;
 260         pud_t *pud;
 261         pmd_t *pmd;
 262         pte_t *pte = NULL;
 263
 264         pgd = pgd_offset(mm, addr);
 265         pud = pud_alloc(mm, pgd, addr);
 266         if (pud) {
 267                 pmd = pmd_alloc(mm, pud, addr);
 268                 if (!pmd)
 269                         return NULL;
 270
 271                 if (sz >= PMD_SIZE)
 272                         pte = (pte_t *)pmd;
 273                 else
 274                         pte = pte_alloc_map(mm, pmd, addr);
 275         }
 276
 277         return pte;
 278 }
 279
 280 pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
 281 {
 282         pgd_t *pgd;
 283         pud_t *pud;
 284         pmd_t *pmd;
 285         pte_t *pte = NULL;
 286
 287         pgd = pgd_offset(mm, addr);
 288         if (!pgd_none(*pgd)) {
 289                 pud = pud_offset(pgd, addr);
 290                 if (!pud_none(*pud)) {
 291                         pmd = pmd_offset(pud, addr);
 292                         if (!pmd_none(*pmd)) {
 293                                 if (is_hugetlb_pmd(*pmd))
 294                                         pte = (pte_t *)pmd;
 295                                 else
 296                                         pte = pte_offset_map(pmd, addr);
 297                         }
 298                 }
 299         }
 300
 301         return pte;
 302 }
 303
 304 void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
 305                      pte_t *ptep, pte_t entry)
 306 {
 307         unsigned int i, nptes, orig_shift, shift;
 308         unsigned long size;
 309         pte_t orig;
 310
 311         size = huge_tte_to_size(entry);
 312         shift = size >= HPAGE_SIZE ? PMD_SHIFT : PAGE_SHIFT;
 313         nptes = size >> shift;
 314
 315         if (!pte_present(*ptep) && pte_present(entry))
 316                 mm->context.hugetlb_pte_count += nptes;
 317
 318         addr &= ~(size - 1);
 319         orig = *ptep;
 320         orig_shift = pte_none(orig) ? PAGE_SHIFT : huge_tte_to_shift(orig);
 321
 322         for (i = 0; i < nptes; i++)
 323                 ptep[i] = __pte(pte_val(entry) + (i << shift));
 324
 325         maybe_tlb_batch_add(mm, addr, ptep, orig, 0, orig_shift);
 326         /* An HPAGE_SIZE'ed page is composed of two REAL_HPAGE_SIZE'ed pages */
 327         if (size == HPAGE_SIZE)
 328                 maybe_tlb_batch_add(mm, addr + REAL_HPAGE_SIZE, ptep, orig, 0,
 329                                     orig_shift);
 330 }
 331
 332 pte_t huge_ptep_get_and_clear(struct mm_struct *mm, unsigned long addr,
 333                               pte_t *ptep)
 334 {
 335         unsigned int i, nptes, hugepage_shift;
 336         unsigned long size;
 337         pte_t entry;
 338
 339         entry = *ptep;
 340         size = huge_tte_to_size(entry);
 341         if (size >= HPAGE_SIZE)
 342                 nptes = size >> PMD_SHIFT;
 343         else
 344                 nptes = size >> PAGE_SHIFT;
 345
 346         hugepage_shift = pte_none(entry) ? PAGE_SHIFT :
 347                 huge_tte_to_shift(entry);
 348
 349         if (pte_present(entry))
 350                 mm->context.hugetlb_pte_count -= nptes;
 351
 352         addr &= ~(size - 1);
 353         for (i = 0; i < nptes; i++)
 354                 ptep[i] = __pte(0UL);
 355
 356         maybe_tlb_batch_add(mm, addr, ptep, entry, 0, hugepage_shift);
 357         /* An HPAGE_SIZE'ed page is composed of two REAL_HPAGE_SIZE'ed pages */
 358         if (size == HPAGE_SIZE)
 359                 maybe_tlb_batch_add(mm, addr + REAL_HPAGE_SIZE, ptep, entry, 0,
 360                                     hugepage_shift);
 361
 362         return entry;
 363 }
 364
 365 int pmd_huge(pmd_t pmd)
 366 {
 367         return !pmd_none(pmd) &&
 368                 (pmd_val(pmd) & (_PAGE_VALID|_PAGE_PMD_HUGE)) != _PAGE_VALID;
 369 }
 370
 371 int pud_huge(pud_t pud)
 372 {
 373         return 0;
 374 }
 375
 376 static void hugetlb_free_pte_range(struct mmu_gather *tlb, pmd_t *pmd,
 377                            unsigned long addr)
 378 {
 379         pgtable_t token = pmd_pgtable(*pmd);
 380
 381         pmd_clear(pmd);
 382         pte_free_tlb(tlb, token, addr);
 383         atomic_long_dec(&tlb->mm->nr_ptes);
 384 }
 385
 386 static void hugetlb_free_pmd_range(struct mmu_gather *tlb, pud_t *pud,
 387                                    unsigned long addr, unsigned long end,
 388                                    unsigned long floor, unsigned long ceiling)
 389 {
 390         pmd_t *pmd;
 391         unsigned long next;
 392         unsigned long start;
 393
 394         start = addr;
 395         pmd = pmd_offset(pud, addr);
 396         do {
 397                 next = pmd_addr_end(addr, end);
 398                 if (pmd_none(*pmd))
 399                         continue;
 400                 if (is_hugetlb_pmd(*pmd))
 401                         pmd_clear(pmd);
 402                 else
 403                         hugetlb_free_pte_range(tlb, pmd, addr);
 404         } while (pmd++, addr = next, addr != end);
 405
 406         start &= PUD_MASK;
 407         if (start < floor)
 408                 return;
 409         if (ceiling) {
 410                 ceiling &= PUD_MASK;
 411                 if (!ceiling)
 412                         return;
 413         }
 414         if (end - 1 > ceiling - 1)
 415                 return;
 416
 417         pmd = pmd_offset(pud, start);
 418         pud_clear(pud);
 419         pmd_free_tlb(tlb, pmd, start);
 420         mm_dec_nr_pmds(tlb->mm);
 421 }
 422
 423 static void hugetlb_free_pud_range(struct mmu_gather *tlb, pgd_t *pgd,
 424                                    unsigned long addr, unsigned long end,
 425                                    unsigned long floor, unsigned long ceiling)
 426 {
 427         pud_t *pud;
 428         unsigned long next;
 429         unsigned long start;
 430
 431         start = addr;
 432         pud = pud_offset(pgd, addr);
 433         do {
 434                 next = pud_addr_end(addr, end);
 435                 if (pud_none_or_clear_bad(pud))
 436                         continue;
 437                 hugetlb_free_pmd_range(tlb, pud, addr, next, floor,
 438                                        ceiling);
 439         } while (pud++, addr = next, addr != end);
 440
 441         start &= PGDIR_MASK;
 442         if (start < floor)
 443                 return;
 444         if (ceiling) {
 445                 ceiling &= PGDIR_MASK;
 446                 if (!ceiling)
 447                         return;
 448         }
 449         if (end - 1 > ceiling - 1)
 450                 return;
 451
 452         pud = pud_offset(pgd, start);
 453         pgd_clear(pgd);
 454         pud_free_tlb(tlb, pud, start);
 455 }
 456
 457 void hugetlb_free_pgd_range(struct mmu_gather *tlb,
 458                             unsigned long addr, unsigned long end,
 459                             unsigned long floor, unsigned long ceiling)
 460 {
 461         pgd_t *pgd;
 462         unsigned long next;
 463
 464         addr &= PMD_MASK;
 465         if (addr < floor) {
 466                 addr += PMD_SIZE;
 467                 if (!addr)
 468                         return;
 469         }
 470         if (ceiling) {
 471                 ceiling &= PMD_MASK;
 472                 if (!ceiling)
 473                         return;
 474         }
 475         if (end - 1 > ceiling - 1)
 476                 end -= PMD_SIZE;
 477         if (addr > end - 1)
 478                 return;
 479
 480         pgd = pgd_offset(tlb->mm, addr);
 481         do {
 482                 next = pgd_addr_end(addr, end);
 483                 if (pgd_none_or_clear_bad(pgd))
 484                         continue;
 485                 hugetlb_free_pud_range(tlb, pgd, addr, next, floor, ceiling);
 486         } while (pgd++, addr = next, addr != end);
 487 }