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_256MB_SHIFT:
 147                 hugepage_size = _PAGE_SZ256MB_4V;
 148                 pte_val(entry) |= _PAGE_PMD_HUGE;
 149                 break;
 150         case HPAGE_SHIFT:
 151                 pte_val(entry) |= _PAGE_PMD_HUGE;
 152                 break;
 153         case HPAGE_64K_SHIFT:
 154                 hugepage_size = _PAGE_SZ64K_4V;
 155                 break;
 156         default:
 157                 WARN_ONCE(1, "unsupported hugepage shift=%u\n", shift);
 158         }
 159
 160         pte_val(entry) = pte_val(entry) | hugepage_size;
 161         return entry;
 162 }
 163
 164 static pte_t hugepage_shift_to_tte(pte_t entry, unsigned int shift)
 165 {
 166         if (tlb_type == hypervisor)
 167                 return sun4v_hugepage_shift_to_tte(entry, shift);
 168         else
 169                 return sun4u_hugepage_shift_to_tte(entry, shift);
 170 }
 171
 172 pte_t arch_make_huge_pte(pte_t entry, struct vm_area_struct *vma,
 173                          struct page *page, int writeable)
 174 {
 175         unsigned int shift = huge_page_shift(hstate_vma(vma));
 176
 177         return hugepage_shift_to_tte(entry, shift);
 178 }
 179
 180 static unsigned int sun4v_huge_tte_to_shift(pte_t entry)
 181 {
 182         unsigned long tte_szbits = pte_val(entry) & _PAGE_SZALL_4V;
 183         unsigned int shift;
 184
 185         switch (tte_szbits) {
 186         case _PAGE_SZ256MB_4V:
 187                 shift = HPAGE_256MB_SHIFT;
 188                 break;
 189         case _PAGE_SZ4MB_4V:
 190                 shift = REAL_HPAGE_SHIFT;
 191                 break;
 192         case _PAGE_SZ64K_4V:
 193                 shift = HPAGE_64K_SHIFT;
 194                 break;
 195         default:
 196                 shift = PAGE_SHIFT;
 197                 break;
 198         }
 199         return shift;
 200 }
 201
 202 static unsigned int sun4u_huge_tte_to_shift(pte_t entry)
 203 {
 204         unsigned long tte_szbits = pte_val(entry) & _PAGE_SZALL_4U;
 205         unsigned int shift;
 206
 207         switch (tte_szbits) {
 208         case _PAGE_SZ256MB_4U:
 209                 shift = HPAGE_256MB_SHIFT;
 210                 break;
 211         case _PAGE_SZ4MB_4U:
 212                 shift = REAL_HPAGE_SHIFT;
 213                 break;
 214         case _PAGE_SZ64K_4U:
 215                 shift = HPAGE_64K_SHIFT;
 216                 break;
 217         default:
 218                 shift = PAGE_SHIFT;
 219                 break;
 220         }
 221         return shift;
 222 }
 223
 224 static unsigned int huge_tte_to_shift(pte_t entry)
 225 {
 226         unsigned long shift;
 227
 228         if (tlb_type == hypervisor)
 229                 shift = sun4v_huge_tte_to_shift(entry);
 230         else
 231                 shift = sun4u_huge_tte_to_shift(entry);
 232
 233         if (shift == PAGE_SHIFT)
 234                 WARN_ONCE(1, "tto_to_shift: invalid hugepage tte=0x%lx\n",
 235                           pte_val(entry));
 236
 237         return shift;
 238 }
 239
 240 static unsigned long huge_tte_to_size(pte_t pte)
 241 {
 242         unsigned long size = 1UL << huge_tte_to_shift(pte);
 243
 244         if (size == REAL_HPAGE_SIZE)
 245                 size = HPAGE_SIZE;
 246         return size;
 247 }
 248
 249 pte_t *huge_pte_alloc(struct mm_struct *mm,
 250                         unsigned long addr, unsigned long sz)
 251 {
 252         pgd_t *pgd;
 253         pud_t *pud;
 254         pmd_t *pmd;
 255         pte_t *pte = NULL;
 256
 257         pgd = pgd_offset(mm, addr);
 258         pud = pud_alloc(mm, pgd, addr);
 259         if (pud) {
 260                 pmd = pmd_alloc(mm, pud, addr);
 261                 if (!pmd)
 262                         return NULL;
 263
 264                 if (sz == PMD_SHIFT)
 265                         pte = (pte_t *)pmd;
 266                 else
 267                         pte = pte_alloc_map(mm, pmd, addr);
 268         }
 269
 270         return pte;
 271 }
 272
 273 pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
 274 {
 275         pgd_t *pgd;
 276         pud_t *pud;
 277         pmd_t *pmd;
 278         pte_t *pte = NULL;
 279
 280         pgd = pgd_offset(mm, addr);
 281         if (!pgd_none(*pgd)) {
 282                 pud = pud_offset(pgd, addr);
 283                 if (!pud_none(*pud)) {
 284                         pmd = pmd_offset(pud, addr);
 285                         if (!pmd_none(*pmd)) {
 286                                 if (is_hugetlb_pmd(*pmd))
 287                                         pte = (pte_t *)pmd;
 288                                 else
 289                                         pte = pte_offset_map(pmd, addr);
 290                         }
 291                 }
 292         }
 293
 294         return pte;
 295 }
 296
 297 void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
 298                      pte_t *ptep, pte_t entry)
 299 {
 300         unsigned int i, nptes, orig_shift, shift;
 301         unsigned long size;
 302         pte_t orig;
 303
 304         size = huge_tte_to_size(entry);
 305         shift = size >= HPAGE_SIZE ? PMD_SHIFT : PAGE_SHIFT;
 306         nptes = size >> shift;
 307
 308         if (!pte_present(*ptep) && pte_present(entry))
 309                 mm->context.hugetlb_pte_count += nptes;
 310
 311         addr &= ~(size - 1);
 312         orig = *ptep;
 313         orig_shift = pte_none(orig) ? PAGE_SHIFT : huge_tte_to_shift(orig);
 314
 315         for (i = 0; i < nptes; i++)
 316                 ptep[i] = __pte(pte_val(entry) + (i << shift));
 317
 318         maybe_tlb_batch_add(mm, addr, ptep, orig, 0, orig_shift);
 319         /* An HPAGE_SIZE'ed page is composed of two REAL_HPAGE_SIZE'ed pages */
 320         if (size == HPAGE_SIZE)
 321                 maybe_tlb_batch_add(mm, addr + REAL_HPAGE_SIZE, ptep, orig, 0,
 322                                     orig_shift);
 323 }
 324
 325 pte_t huge_ptep_get_and_clear(struct mm_struct *mm, unsigned long addr,
 326                               pte_t *ptep)
 327 {
 328         unsigned int i, nptes, hugepage_shift;
 329         unsigned long size;
 330         pte_t entry;
 331
 332         entry = *ptep;
 333         size = huge_tte_to_size(entry);
 334         if (size >= HPAGE_SIZE)
 335                 nptes = size >> PMD_SHIFT;
 336         else
 337                 nptes = size >> PAGE_SHIFT;
 338
 339         hugepage_shift = pte_none(entry) ? PAGE_SHIFT :
 340                 huge_tte_to_shift(entry);
 341
 342         if (pte_present(entry))
 343                 mm->context.hugetlb_pte_count -= nptes;
 344
 345         addr &= ~(size - 1);
 346         for (i = 0; i < nptes; i++)
 347                 ptep[i] = __pte(0UL);
 348
 349         maybe_tlb_batch_add(mm, addr, ptep, entry, 0, hugepage_shift);
 350         /* An HPAGE_SIZE'ed page is composed of two REAL_HPAGE_SIZE'ed pages */
 351         if (size == HPAGE_SIZE)
 352                 maybe_tlb_batch_add(mm, addr + REAL_HPAGE_SIZE, ptep, entry, 0,
 353                                     hugepage_shift);
 354
 355         return entry;
 356 }
 357
 358 int pmd_huge(pmd_t pmd)
 359 {
 360         return !pmd_none(pmd) &&
 361                 (pmd_val(pmd) & (_PAGE_VALID|_PAGE_PMD_HUGE)) != _PAGE_VALID;
 362 }
 363
 364 int pud_huge(pud_t pud)
 365 {
 366         return 0;
 367 }
 368
 369 static void hugetlb_free_pte_range(struct mmu_gather *tlb, pmd_t *pmd,
 370                            unsigned long addr)
 371 {
 372         pgtable_t token = pmd_pgtable(*pmd);
 373
 374         pmd_clear(pmd);
 375         pte_free_tlb(tlb, token, addr);
 376         atomic_long_dec(&tlb->mm->nr_ptes);
 377 }
 378
 379 static void hugetlb_free_pmd_range(struct mmu_gather *tlb, pud_t *pud,
 380                                    unsigned long addr, unsigned long end,
 381                                    unsigned long floor, unsigned long ceiling)
 382 {
 383         pmd_t *pmd;
 384         unsigned long next;
 385         unsigned long start;
 386
 387         start = addr;
 388         pmd = pmd_offset(pud, addr);
 389         do {
 390                 next = pmd_addr_end(addr, end);
 391                 if (pmd_none(*pmd))
 392                         continue;
 393                 if (is_hugetlb_pmd(*pmd))
 394                         pmd_clear(pmd);
 395                 else
 396                         hugetlb_free_pte_range(tlb, pmd, addr);
 397         } while (pmd++, addr = next, addr != end);
 398
 399         start &= PUD_MASK;
 400         if (start < floor)
 401                 return;
 402         if (ceiling) {
 403                 ceiling &= PUD_MASK;
 404                 if (!ceiling)
 405                         return;
 406         }
 407         if (end - 1 > ceiling - 1)
 408                 return;
 409
 410         pmd = pmd_offset(pud, start);
 411         pud_clear(pud);
 412         pmd_free_tlb(tlb, pmd, start);
 413         mm_dec_nr_pmds(tlb->mm);
 414 }
 415
 416 static void hugetlb_free_pud_range(struct mmu_gather *tlb, pgd_t *pgd,
 417                                    unsigned long addr, unsigned long end,
 418                                    unsigned long floor, unsigned long ceiling)
 419 {
 420         pud_t *pud;
 421         unsigned long next;
 422         unsigned long start;
 423
 424         start = addr;
 425         pud = pud_offset(pgd, addr);
 426         do {
 427                 next = pud_addr_end(addr, end);
 428                 if (pud_none_or_clear_bad(pud))
 429                         continue;
 430                 hugetlb_free_pmd_range(tlb, pud, addr, next, floor,
 431                                        ceiling);
 432         } while (pud++, addr = next, addr != end);
 433
 434         start &= PGDIR_MASK;
 435         if (start < floor)
 436                 return;
 437         if (ceiling) {
 438                 ceiling &= PGDIR_MASK;
 439                 if (!ceiling)
 440                         return;
 441         }
 442         if (end - 1 > ceiling - 1)
 443                 return;
 444
 445         pud = pud_offset(pgd, start);
 446         pgd_clear(pgd);
 447         pud_free_tlb(tlb, pud, start);
 448 }
 449
 450 void hugetlb_free_pgd_range(struct mmu_gather *tlb,
 451                             unsigned long addr, unsigned long end,
 452                             unsigned long floor, unsigned long ceiling)
 453 {
 454         pgd_t *pgd;
 455         unsigned long next;
 456
 457         pgd = pgd_offset(tlb->mm, addr);
 458         do {
 459                 next = pgd_addr_end(addr, end);
 460                 if (pgd_none_or_clear_bad(pgd))
 461                         continue;
 462                 hugetlb_free_pud_range(tlb, pgd, addr, next, floor, ceiling);
 463         } while (pgd++, addr = next, addr != end);
 464 }