arch/s390/mm/hugetlbpage.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  IBM System z Huge TLB Page Support for Kernel.
   4  *
   5  *    Copyright IBM Corp. 2007,2020
   6  *    Author(s): Gerald Schaefer <gerald.schaefer@de.ibm.com>
   7  */
   8
   9 #define KMSG_COMPONENT "hugetlb"
  10 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
  11
  12 #include <linux/mm.h>
  13 #include <linux/hugetlb.h>
  14 #include <linux/mman.h>
  15 #include <linux/sched/mm.h>
  16 #include <linux/security.h>
  17
  18 /*
  19  * If the bit selected by single-bit bitmask "a" is set within "x", move
  20  * it to the position indicated by single-bit bitmask "b".
  21  */
  22 #define move_set_bit(x, a, b)   (((x) & (a)) >> ilog2(a) << ilog2(b))
  23
  24 static inline unsigned long __pte_to_rste(pte_t pte)
  25 {
  26         unsigned long rste;
  27
  28         /*
  29          * Convert encoding               pte bits      pmd / pud bits
  30          *                              lIR.uswrdy.p    dy..R...I...wr
  31          * empty                        010.000000.0 -> 00..0...1...00
  32          * prot-none, clean, old        111.000000.1 -> 00..1...1...00
  33          * prot-none, clean, young      111.000001.1 -> 01..1...1...00
  34          * prot-none, dirty, old        111.000010.1 -> 10..1...1...00
  35          * prot-none, dirty, young      111.000011.1 -> 11..1...1...00
  36          * read-only, clean, old        111.000100.1 -> 00..1...1...01
  37          * read-only, clean, young      101.000101.1 -> 01..1...0...01
  38          * read-only, dirty, old        111.000110.1 -> 10..1...1...01
  39          * read-only, dirty, young      101.000111.1 -> 11..1...0...01
  40          * read-write, clean, old       111.001100.1 -> 00..1...1...11
  41          * read-write, clean, young     101.001101.1 -> 01..1...0...11
  42          * read-write, dirty, old       110.001110.1 -> 10..0...1...11
  43          * read-write, dirty, young     100.001111.1 -> 11..0...0...11
  44          * HW-bits: R read-only, I invalid
  45          * SW-bits: p present, y young, d dirty, r read, w write, s special,
  46          *          u unused, l large
  47          */
  48         if (pte_present(pte)) {
  49                 rste = pte_val(pte) & PAGE_MASK;
  50                 rste |= move_set_bit(pte_val(pte), _PAGE_READ,
  51                                      _SEGMENT_ENTRY_READ);
  52                 rste |= move_set_bit(pte_val(pte), _PAGE_WRITE,
  53                                      _SEGMENT_ENTRY_WRITE);
  54                 rste |= move_set_bit(pte_val(pte), _PAGE_INVALID,
  55                                      _SEGMENT_ENTRY_INVALID);
  56                 rste |= move_set_bit(pte_val(pte), _PAGE_PROTECT,
  57                                      _SEGMENT_ENTRY_PROTECT);
  58                 rste |= move_set_bit(pte_val(pte), _PAGE_DIRTY,
  59                                      _SEGMENT_ENTRY_DIRTY);
  60                 rste |= move_set_bit(pte_val(pte), _PAGE_YOUNG,
  61                                      _SEGMENT_ENTRY_YOUNG);
  62 #ifdef CONFIG_MEM_SOFT_DIRTY
  63                 rste |= move_set_bit(pte_val(pte), _PAGE_SOFT_DIRTY,
  64                                      _SEGMENT_ENTRY_SOFT_DIRTY);
  65 #endif
  66                 rste |= move_set_bit(pte_val(pte), _PAGE_NOEXEC,
  67                                      _SEGMENT_ENTRY_NOEXEC);
  68         } else
  69                 rste = _SEGMENT_ENTRY_EMPTY;
  70         return rste;
  71 }
  72
  73 static inline pte_t __rste_to_pte(unsigned long rste)
  74 {
  75         int present;
  76         pte_t pte;
  77
  78         if ((rste & _REGION_ENTRY_TYPE_MASK) == _REGION_ENTRY_TYPE_R3)
  79                 present = pud_present(__pud(rste));
  80         else
  81                 present = pmd_present(__pmd(rste));
  82
  83         /*
  84          * Convert encoding             pmd / pud bits      pte bits
  85          *                              dy..R...I...wr    lIR.uswrdy.p
  86          * empty                        00..0...1...00 -> 010.000000.0
  87          * prot-none, clean, old        00..1...1...00 -> 111.000000.1
  88          * prot-none, clean, young      01..1...1...00 -> 111.000001.1
  89          * prot-none, dirty, old        10..1...1...00 -> 111.000010.1
  90          * prot-none, dirty, young      11..1...1...00 -> 111.000011.1
  91          * read-only, clean, old        00..1...1...01 -> 111.000100.1
  92          * read-only, clean, young      01..1...0...01 -> 101.000101.1
  93          * read-only, dirty, old        10..1...1...01 -> 111.000110.1
  94          * read-only, dirty, young      11..1...0...01 -> 101.000111.1
  95          * read-write, clean, old       00..1...1...11 -> 111.001100.1
  96          * read-write, clean, young     01..1...0...11 -> 101.001101.1
  97          * read-write, dirty, old       10..0...1...11 -> 110.001110.1
  98          * read-write, dirty, young     11..0...0...11 -> 100.001111.1
  99          * HW-bits: R read-only, I invalid
 100          * SW-bits: p present, y young, d dirty, r read, w write, s special,
 101          *          u unused, l large
 102          */
 103         if (present) {
 104                 pte_val(pte) = rste & _SEGMENT_ENTRY_ORIGIN_LARGE;
 105                 pte_val(pte) |= _PAGE_LARGE | _PAGE_PRESENT;
 106                 pte_val(pte) |= move_set_bit(rste, _SEGMENT_ENTRY_READ,
 107                                              _PAGE_READ);
 108                 pte_val(pte) |= move_set_bit(rste, _SEGMENT_ENTRY_WRITE,
 109                                              _PAGE_WRITE);
 110                 pte_val(pte) |= move_set_bit(rste, _SEGMENT_ENTRY_INVALID,
 111                                              _PAGE_INVALID);
 112                 pte_val(pte) |= move_set_bit(rste, _SEGMENT_ENTRY_PROTECT,
 113                                              _PAGE_PROTECT);
 114                 pte_val(pte) |= move_set_bit(rste, _SEGMENT_ENTRY_DIRTY,
 115                                              _PAGE_DIRTY);
 116                 pte_val(pte) |= move_set_bit(rste, _SEGMENT_ENTRY_YOUNG,
 117                                              _PAGE_YOUNG);
 118 #ifdef CONFIG_MEM_SOFT_DIRTY
 119                 pte_val(pte) |= move_set_bit(rste, _SEGMENT_ENTRY_SOFT_DIRTY,
 120                                              _PAGE_DIRTY);
 121 #endif
 122                 pte_val(pte) |= move_set_bit(rste, _SEGMENT_ENTRY_NOEXEC,
 123                                              _PAGE_NOEXEC);
 124         } else
 125                 pte_val(pte) = _PAGE_INVALID;
 126         return pte;
 127 }
 128
 129 static void clear_huge_pte_skeys(struct mm_struct *mm, unsigned long rste)
 130 {
 131         struct page *page;
 132         unsigned long size, paddr;
 133
 134         if (!mm_uses_skeys(mm) ||
 135             rste & _SEGMENT_ENTRY_INVALID)
 136                 return;
 137
 138         if ((rste & _REGION_ENTRY_TYPE_MASK) == _REGION_ENTRY_TYPE_R3) {
 139                 page = pud_page(__pud(rste));
 140                 size = PUD_SIZE;
 141                 paddr = rste & PUD_MASK;
 142         } else {
 143                 page = pmd_page(__pmd(rste));
 144                 size = PMD_SIZE;
 145                 paddr = rste & PMD_MASK;
 146         }
 147
 148         if (!test_and_set_bit(PG_arch_1, &page->flags))
 149                 __storage_key_init_range(paddr, paddr + size - 1);
 150 }
 151
 152 void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
 153                      pte_t *ptep, pte_t pte)
 154 {
 155         unsigned long rste;
 156
 157         rste = __pte_to_rste(pte);
 158         if (!MACHINE_HAS_NX)
 159                 rste &= ~_SEGMENT_ENTRY_NOEXEC;
 160
 161         /* Set correct table type for 2G hugepages */
 162         if ((pte_val(*ptep) & _REGION_ENTRY_TYPE_MASK) == _REGION_ENTRY_TYPE_R3) {
 163                 if (likely(pte_present(pte)))
 164                         rste |= _REGION3_ENTRY_LARGE;
 165                 rste |= _REGION_ENTRY_TYPE_R3;
 166         } else if (likely(pte_present(pte)))
 167                 rste |= _SEGMENT_ENTRY_LARGE;
 168
 169         clear_huge_pte_skeys(mm, rste);
 170         pte_val(*ptep) = rste;
 171 }
 172
 173 pte_t huge_ptep_get(pte_t *ptep)
 174 {
 175         return __rste_to_pte(pte_val(*ptep));
 176 }
 177
 178 pte_t huge_ptep_get_and_clear(struct mm_struct *mm,
 179                               unsigned long addr, pte_t *ptep)
 180 {
 181         pte_t pte = huge_ptep_get(ptep);
 182         pmd_t *pmdp = (pmd_t *) ptep;
 183         pud_t *pudp = (pud_t *) ptep;
 184
 185         if ((pte_val(*ptep) & _REGION_ENTRY_TYPE_MASK) == _REGION_ENTRY_TYPE_R3)
 186                 pudp_xchg_direct(mm, addr, pudp, __pud(_REGION3_ENTRY_EMPTY));
 187         else
 188                 pmdp_xchg_direct(mm, addr, pmdp, __pmd(_SEGMENT_ENTRY_EMPTY));
 189         return pte;
 190 }
 191
 192 pte_t *huge_pte_alloc(struct mm_struct *mm,
 193                         unsigned long addr, unsigned long sz)
 194 {
 195         pgd_t *pgdp;
 196         p4d_t *p4dp;
 197         pud_t *pudp;
 198         pmd_t *pmdp = NULL;
 199
 200         pgdp = pgd_offset(mm, addr);
 201         p4dp = p4d_alloc(mm, pgdp, addr);
 202         if (p4dp) {
 203                 pudp = pud_alloc(mm, p4dp, addr);
 204                 if (pudp) {
 205                         if (sz == PUD_SIZE)
 206                                 return (pte_t *) pudp;
 207                         else if (sz == PMD_SIZE)
 208                                 pmdp = pmd_alloc(mm, pudp, addr);
 209                 }
 210         }
 211         return (pte_t *) pmdp;
 212 }
 213
 214 pte_t *huge_pte_offset(struct mm_struct *mm,
 215                        unsigned long addr, unsigned long sz)
 216 {
 217         pgd_t *pgdp;
 218         p4d_t *p4dp;
 219         pud_t *pudp;
 220         pmd_t *pmdp = NULL;
 221
 222         pgdp = pgd_offset(mm, addr);
 223         if (pgd_present(*pgdp)) {
 224                 p4dp = p4d_offset(pgdp, addr);
 225                 if (p4d_present(*p4dp)) {
 226                         pudp = pud_offset(p4dp, addr);
 227                         if (pud_present(*pudp)) {
 228                                 if (pud_large(*pudp))
 229                                         return (pte_t *) pudp;
 230                                 pmdp = pmd_offset(pudp, addr);
 231                         }
 232                 }
 233         }
 234         return (pte_t *) pmdp;
 235 }
 236
 237 int pmd_huge(pmd_t pmd)
 238 {
 239         return pmd_large(pmd);
 240 }
 241
 242 int pud_huge(pud_t pud)
 243 {
 244         return pud_large(pud);
 245 }
 246
 247 struct page *
 248 follow_huge_pud(struct mm_struct *mm, unsigned long address,
 249                 pud_t *pud, int flags)
 250 {
 251         if (flags & FOLL_GET)
 252                 return NULL;
 253
 254         return pud_page(*pud) + ((address & ~PUD_MASK) >> PAGE_SHIFT);
 255 }
 256
 257 static __init int setup_hugepagesz(char *opt)
 258 {
 259         unsigned long size;
 260         char *string = opt;
 261
 262         size = memparse(opt, &opt);
 263         if (MACHINE_HAS_EDAT1 && size == PMD_SIZE) {
 264                 hugetlb_add_hstate(PMD_SHIFT - PAGE_SHIFT);
 265         } else if (MACHINE_HAS_EDAT2 && size == PUD_SIZE) {
 266                 hugetlb_add_hstate(PUD_SHIFT - PAGE_SHIFT);
 267         } else {
 268                 hugetlb_bad_size();
 269                 pr_err("hugepagesz= specifies an unsupported page size %s\n",
 270                         string);
 271                 return 0;
 272         }
 273         return 1;
 274 }
 275 __setup("hugepagesz=", setup_hugepagesz);
 276
 277 static unsigned long hugetlb_get_unmapped_area_bottomup(struct file *file,
 278                 unsigned long addr, unsigned long len,
 279                 unsigned long pgoff, unsigned long flags)
 280 {
 281         struct hstate *h = hstate_file(file);
 282         struct vm_unmapped_area_info info;
 283
 284         info.flags = 0;
 285         info.length = len;
 286         info.low_limit = current->mm->mmap_base;
 287         info.high_limit = TASK_SIZE;
 288         info.align_mask = PAGE_MASK & ~huge_page_mask(h);
 289         info.align_offset = 0;
 290         return vm_unmapped_area(&info);
 291 }
 292
 293 static unsigned long hugetlb_get_unmapped_area_topdown(struct file *file,
 294                 unsigned long addr0, unsigned long len,
 295                 unsigned long pgoff, unsigned long flags)
 296 {
 297         struct hstate *h = hstate_file(file);
 298         struct vm_unmapped_area_info info;
 299         unsigned long addr;
 300
 301         info.flags = VM_UNMAPPED_AREA_TOPDOWN;
 302         info.length = len;
 303         info.low_limit = max(PAGE_SIZE, mmap_min_addr);
 304         info.high_limit = current->mm->mmap_base;
 305         info.align_mask = PAGE_MASK & ~huge_page_mask(h);
 306         info.align_offset = 0;
 307         addr = vm_unmapped_area(&info);
 308
 309         /*
 310          * A failed mmap() very likely causes application failure,
 311          * so fall back to the bottom-up function here. This scenario
 312          * can happen with large stack limits and large mmap()
 313          * allocations.
 314          */
 315         if (addr & ~PAGE_MASK) {
 316                 VM_BUG_ON(addr != -ENOMEM);
 317                 info.flags = 0;
 318                 info.low_limit = TASK_UNMAPPED_BASE;
 319                 info.high_limit = TASK_SIZE;
 320                 addr = vm_unmapped_area(&info);
 321         }
 322
 323         return addr;
 324 }
 325
 326 unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
 327                 unsigned long len, unsigned long pgoff, unsigned long flags)
 328 {
 329         struct hstate *h = hstate_file(file);
 330         struct mm_struct *mm = current->mm;
 331         struct vm_area_struct *vma;
 332
 333         if (len & ~huge_page_mask(h))
 334                 return -EINVAL;
 335         if (len > TASK_SIZE - mmap_min_addr)
 336                 return -ENOMEM;
 337
 338         if (flags & MAP_FIXED) {
 339                 if (prepare_hugepage_range(file, addr, len))
 340                         return -EINVAL;
 341                 goto check_asce_limit;
 342         }
 343
 344         if (addr) {
 345                 addr = ALIGN(addr, huge_page_size(h));
 346                 vma = find_vma(mm, addr);
 347                 if (TASK_SIZE - len >= addr && addr >= mmap_min_addr &&
 348                     (!vma || addr + len <= vm_start_gap(vma)))
 349                         goto check_asce_limit;
 350         }
 351
 352         if (mm->get_unmapped_area == arch_get_unmapped_area)
 353                 addr = hugetlb_get_unmapped_area_bottomup(file, addr, len,
 354                                 pgoff, flags);
 355         else
 356                 addr = hugetlb_get_unmapped_area_topdown(file, addr, len,
 357                                 pgoff, flags);
 358         if (offset_in_page(addr))
 359                 return addr;
 360
 361 check_asce_limit:
 362         return check_asce_limit(mm, addr, len);
 363 }