arch/riscv/mm/hugetlbpage.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <linux/hugetlb.h>
   3 #include <linux/err.h>
   4
   5 #ifdef CONFIG_RISCV_ISA_SVNAPOT
   6 pte_t huge_ptep_get(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
   7 {
   8         unsigned long pte_num;
   9         int i;
  10         pte_t orig_pte = ptep_get(ptep);
  11
  12         if (!pte_present(orig_pte) || !pte_napot(orig_pte))
  13                 return orig_pte;
  14
  15         pte_num = napot_pte_num(napot_cont_order(orig_pte));
  16
  17         for (i = 0; i < pte_num; i++, ptep++) {
  18                 pte_t pte = ptep_get(ptep);
  19
  20                 if (pte_dirty(pte))
  21                         orig_pte = pte_mkdirty(orig_pte);
  22
  23                 if (pte_young(pte))
  24                         orig_pte = pte_mkyoung(orig_pte);
  25         }
  26
  27         return orig_pte;
  28 }
  29
  30 pte_t *huge_pte_alloc(struct mm_struct *mm,
  31                       struct vm_area_struct *vma,
  32                       unsigned long addr,
  33                       unsigned long sz)
  34 {
  35         unsigned long order;
  36         pte_t *pte = NULL;
  37         pgd_t *pgd;
  38         p4d_t *p4d;
  39         pud_t *pud;
  40         pmd_t *pmd;
  41
  42         pgd = pgd_offset(mm, addr);
  43         p4d = p4d_alloc(mm, pgd, addr);
  44         if (!p4d)
  45                 return NULL;
  46
  47         pud = pud_alloc(mm, p4d, addr);
  48         if (!pud)
  49                 return NULL;
  50
  51         if (sz == PUD_SIZE) {
  52                 pte = (pte_t *)pud;
  53                 goto out;
  54         }
  55
  56         if (sz == PMD_SIZE) {
  57                 if (want_pmd_share(vma, addr) && pud_none(pudp_get(pud)))
  58                         pte = huge_pmd_share(mm, vma, addr, pud);
  59                 else
  60                         pte = (pte_t *)pmd_alloc(mm, pud, addr);
  61                 goto out;
  62         }
  63
  64         pmd = pmd_alloc(mm, pud, addr);
  65         if (!pmd)
  66                 return NULL;
  67
  68         for_each_napot_order(order) {
  69                 if (napot_cont_size(order) == sz) {
  70                         pte = pte_alloc_huge(mm, pmd, addr & napot_cont_mask(order));
  71                         break;
  72                 }
  73         }
  74
  75 out:
  76         if (pte) {
  77                 pte_t pteval = ptep_get_lockless(pte);
  78
  79                 WARN_ON_ONCE(pte_present(pteval) && !pte_huge(pteval));
  80         }
  81         return pte;
  82 }
  83
  84 pte_t *huge_pte_offset(struct mm_struct *mm,
  85                        unsigned long addr,
  86                        unsigned long sz)
  87 {
  88         unsigned long order;
  89         pte_t *pte = NULL;
  90         pgd_t *pgd;
  91         p4d_t *p4d;
  92         pud_t *pud;
  93         pmd_t *pmd;
  94
  95         pgd = pgd_offset(mm, addr);
  96         if (!pgd_present(pgdp_get(pgd)))
  97                 return NULL;
  98
  99         p4d = p4d_offset(pgd, addr);
 100         if (!p4d_present(p4dp_get(p4d)))
 101                 return NULL;
 102
 103         pud = pud_offset(p4d, addr);
 104         if (sz == PUD_SIZE)
 105                 /* must be pud huge, non-present or none */
 106                 return (pte_t *)pud;
 107
 108         if (!pud_present(pudp_get(pud)))
 109                 return NULL;
 110
 111         pmd = pmd_offset(pud, addr);
 112         if (sz == PMD_SIZE)
 113                 /* must be pmd huge, non-present or none */
 114                 return (pte_t *)pmd;
 115
 116         if (!pmd_present(pmdp_get(pmd)))
 117                 return NULL;
 118
 119         for_each_napot_order(order) {
 120                 if (napot_cont_size(order) == sz) {
 121                         pte = pte_offset_huge(pmd, addr & napot_cont_mask(order));
 122                         break;
 123                 }
 124         }
 125         return pte;
 126 }
 127
 128 unsigned long hugetlb_mask_last_page(struct hstate *h)
 129 {
 130         unsigned long hp_size = huge_page_size(h);
 131
 132         switch (hp_size) {
 133 #ifndef __PAGETABLE_PMD_FOLDED
 134         case PUD_SIZE:
 135                 return P4D_SIZE - PUD_SIZE;
 136 #endif
 137         case PMD_SIZE:
 138                 return PUD_SIZE - PMD_SIZE;
 139         case napot_cont_size(NAPOT_CONT64KB_ORDER):
 140                 return PMD_SIZE - napot_cont_size(NAPOT_CONT64KB_ORDER);
 141         default:
 142                 break;
 143         }
 144
 145         return 0UL;
 146 }
 147
 148 static pte_t get_clear_contig(struct mm_struct *mm,
 149                               unsigned long addr,
 150                               pte_t *ptep,
 151                               unsigned long pte_num)
 152 {
 153         pte_t orig_pte = ptep_get(ptep);
 154         unsigned long i;
 155
 156         for (i = 0; i < pte_num; i++, addr += PAGE_SIZE, ptep++) {
 157                 pte_t pte = ptep_get_and_clear(mm, addr, ptep);
 158
 159                 if (pte_dirty(pte))
 160                         orig_pte = pte_mkdirty(orig_pte);
 161
 162                 if (pte_young(pte))
 163                         orig_pte = pte_mkyoung(orig_pte);
 164         }
 165
 166         return orig_pte;
 167 }
 168
 169 static pte_t get_clear_contig_flush(struct mm_struct *mm,
 170                                     unsigned long addr,
 171                                     pte_t *ptep,
 172                                     unsigned long pte_num)
 173 {
 174         pte_t orig_pte = get_clear_contig(mm, addr, ptep, pte_num);
 175         struct vm_area_struct vma = TLB_FLUSH_VMA(mm, 0);
 176         bool valid = !pte_none(orig_pte);
 177
 178         if (valid)
 179                 flush_tlb_range(&vma, addr, addr + (PAGE_SIZE * pte_num));
 180
 181         return orig_pte;
 182 }
 183
 184 pte_t arch_make_huge_pte(pte_t entry, unsigned int shift, vm_flags_t flags)
 185 {
 186         unsigned long order;
 187
 188         for_each_napot_order(order) {
 189                 if (shift == napot_cont_shift(order)) {
 190                         entry = pte_mknapot(entry, order);
 191                         break;
 192                 }
 193         }
 194         if (order == NAPOT_ORDER_MAX)
 195                 entry = pte_mkhuge(entry);
 196
 197         return entry;
 198 }
 199
 200 static void clear_flush(struct mm_struct *mm,
 201                         unsigned long addr,
 202                         pte_t *ptep,
 203                         unsigned long pgsize,
 204                         unsigned long ncontig)
 205 {
 206         struct vm_area_struct vma = TLB_FLUSH_VMA(mm, 0);
 207         unsigned long i, saddr = addr;
 208
 209         for (i = 0; i < ncontig; i++, addr += pgsize, ptep++)
 210                 ptep_get_and_clear(mm, addr, ptep);
 211
 212         flush_tlb_range(&vma, saddr, addr);
 213 }
 214
 215 /*
 216  * When dealing with NAPOT mappings, the privileged specification indicates that
 217  * "if an update needs to be made, the OS generally should first mark all of the
 218  * PTEs invalid, then issue SFENCE.VMA instruction(s) covering all 4 KiB regions
 219  * within the range, [...] then update the PTE(s), as described in Section
 220  * 4.2.1.". That's the equivalent of the Break-Before-Make approach used by
 221  * arm64.
 222  */
 223 void set_huge_pte_at(struct mm_struct *mm,
 224                      unsigned long addr,
 225                      pte_t *ptep,
 226                      pte_t pte,
 227                      unsigned long sz)
 228 {
 229         unsigned long hugepage_shift, pgsize;
 230         int i, pte_num;
 231
 232         if (sz >= PGDIR_SIZE)
 233                 hugepage_shift = PGDIR_SHIFT;
 234         else if (sz >= P4D_SIZE)
 235                 hugepage_shift = P4D_SHIFT;
 236         else if (sz >= PUD_SIZE)
 237                 hugepage_shift = PUD_SHIFT;
 238         else if (sz >= PMD_SIZE)
 239                 hugepage_shift = PMD_SHIFT;
 240         else
 241                 hugepage_shift = PAGE_SHIFT;
 242
 243         pte_num = sz >> hugepage_shift;
 244         pgsize = 1 << hugepage_shift;
 245
 246         if (!pte_present(pte)) {
 247                 for (i = 0; i < pte_num; i++, ptep++, addr += pgsize)
 248                         set_ptes(mm, addr, ptep, pte, 1);
 249                 return;
 250         }
 251
 252         if (!pte_napot(pte)) {
 253                 set_ptes(mm, addr, ptep, pte, 1);
 254                 return;
 255         }
 256
 257         clear_flush(mm, addr, ptep, pgsize, pte_num);
 258
 259         for (i = 0; i < pte_num; i++, ptep++, addr += pgsize)
 260                 set_pte_at(mm, addr, ptep, pte);
 261 }
 262
 263 int huge_ptep_set_access_flags(struct vm_area_struct *vma,
 264                                unsigned long addr,
 265                                pte_t *ptep,
 266                                pte_t pte,
 267                                int dirty)
 268 {
 269         struct mm_struct *mm = vma->vm_mm;
 270         unsigned long order;
 271         pte_t orig_pte;
 272         int i, pte_num;
 273
 274         if (!pte_napot(pte))
 275                 return ptep_set_access_flags(vma, addr, ptep, pte, dirty);
 276
 277         order = napot_cont_order(pte);
 278         pte_num = napot_pte_num(order);
 279         ptep = huge_pte_offset(mm, addr, napot_cont_size(order));
 280         orig_pte = get_clear_contig_flush(mm, addr, ptep, pte_num);
 281
 282         if (pte_dirty(orig_pte))
 283                 pte = pte_mkdirty(pte);
 284
 285         if (pte_young(orig_pte))
 286                 pte = pte_mkyoung(pte);
 287
 288         for (i = 0; i < pte_num; i++, addr += PAGE_SIZE, ptep++)
 289                 set_pte_at(mm, addr, ptep, pte);
 290
 291         return true;
 292 }
 293
 294 pte_t huge_ptep_get_and_clear(struct mm_struct *mm,
 295                               unsigned long addr,
 296                               pte_t *ptep)
 297 {
 298         pte_t orig_pte = ptep_get(ptep);
 299         int pte_num;
 300
 301         if (!pte_napot(orig_pte))
 302                 return ptep_get_and_clear(mm, addr, ptep);
 303
 304         pte_num = napot_pte_num(napot_cont_order(orig_pte));
 305
 306         return get_clear_contig(mm, addr, ptep, pte_num);
 307 }
 308
 309 void huge_ptep_set_wrprotect(struct mm_struct *mm,
 310                              unsigned long addr,
 311                              pte_t *ptep)
 312 {
 313         pte_t pte = ptep_get(ptep);
 314         unsigned long order;
 315         pte_t orig_pte;
 316         int i, pte_num;
 317
 318         if (!pte_napot(pte)) {
 319                 ptep_set_wrprotect(mm, addr, ptep);
 320                 return;
 321         }
 322
 323         order = napot_cont_order(pte);
 324         pte_num = napot_pte_num(order);
 325         ptep = huge_pte_offset(mm, addr, napot_cont_size(order));
 326         orig_pte = get_clear_contig_flush(mm, addr, ptep, pte_num);
 327
 328         orig_pte = pte_wrprotect(orig_pte);
 329
 330         for (i = 0; i < pte_num; i++, addr += PAGE_SIZE, ptep++)
 331                 set_pte_at(mm, addr, ptep, orig_pte);
 332 }
 333
 334 pte_t huge_ptep_clear_flush(struct vm_area_struct *vma,
 335                             unsigned long addr,
 336                             pte_t *ptep)
 337 {
 338         pte_t pte = ptep_get(ptep);
 339         int pte_num;
 340
 341         if (!pte_napot(pte))
 342                 return ptep_clear_flush(vma, addr, ptep);
 343
 344         pte_num = napot_pte_num(napot_cont_order(pte));
 345
 346         return get_clear_contig_flush(vma->vm_mm, addr, ptep, pte_num);
 347 }
 348
 349 void huge_pte_clear(struct mm_struct *mm,
 350                     unsigned long addr,
 351                     pte_t *ptep,
 352                     unsigned long sz)
 353 {
 354         pte_t pte = ptep_get(ptep);
 355         int i, pte_num;
 356
 357         if (!pte_napot(pte)) {
 358                 pte_clear(mm, addr, ptep);
 359                 return;
 360         }
 361
 362         pte_num = napot_pte_num(napot_cont_order(pte));
 363         for (i = 0; i < pte_num; i++, addr += PAGE_SIZE, ptep++)
 364                 pte_clear(mm, addr, ptep);
 365 }
 366
 367 static bool is_napot_size(unsigned long size)
 368 {
 369         unsigned long order;
 370
 371         if (!has_svnapot())
 372                 return false;
 373
 374         for_each_napot_order(order) {
 375                 if (size == napot_cont_size(order))
 376                         return true;
 377         }
 378         return false;
 379 }
 380
 381 static __init int napot_hugetlbpages_init(void)
 382 {
 383         if (has_svnapot()) {
 384                 unsigned long order;
 385
 386                 for_each_napot_order(order)
 387                         hugetlb_add_hstate(order);
 388         }
 389         return 0;
 390 }
 391 arch_initcall(napot_hugetlbpages_init);
 392
 393 #else
 394
 395 static bool is_napot_size(unsigned long size)
 396 {
 397         return false;
 398 }
 399
 400 #endif /*CONFIG_RISCV_ISA_SVNAPOT*/
 401
 402 static bool __hugetlb_valid_size(unsigned long size)
 403 {
 404         if (size == HPAGE_SIZE)
 405                 return true;
 406         else if (IS_ENABLED(CONFIG_64BIT) && size == PUD_SIZE)
 407                 return true;
 408         else if (is_napot_size(size))
 409                 return true;
 410         else
 411                 return false;
 412 }
 413
 414 bool __init arch_hugetlb_valid_size(unsigned long size)
 415 {
 416         return __hugetlb_valid_size(size);
 417 }
 418
 419 #ifdef CONFIG_ARCH_ENABLE_HUGEPAGE_MIGRATION
 420 bool arch_hugetlb_migration_supported(struct hstate *h)
 421 {
 422         return __hugetlb_valid_size(huge_page_size(h));
 423 }
 424 #endif
 425
 426 #ifdef CONFIG_CONTIG_ALLOC
 427 static __init int gigantic_pages_init(void)
 428 {
 429         /* With CONTIG_ALLOC, we can allocate gigantic pages at runtime */
 430         if (IS_ENABLED(CONFIG_64BIT))
 431                 hugetlb_add_hstate(PUD_SHIFT - PAGE_SHIFT);
 432         return 0;
 433 }
 434 arch_initcall(gigantic_pages_init);
 435 #endif