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_SOFT_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 void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
 130                      pte_t *ptep, pte_t pte)
 131 {
 132         unsigned long rste;
 133
 134         rste = __pte_to_rste(pte);
 135         if (!MACHINE_HAS_NX)
 136                 rste &= ~_SEGMENT_ENTRY_NOEXEC;
 137
 138         /* Set correct table type for 2G hugepages */
 139         if ((pte_val(*ptep) & _REGION_ENTRY_TYPE_MASK) == _REGION_ENTRY_TYPE_R3)
 140                 rste |= _REGION_ENTRY_TYPE_R3 | _REGION3_ENTRY_LARGE;
 141         else
 142                 rste |= _SEGMENT_ENTRY_LARGE;
 143         pte_val(*ptep) = rste;
 144 }
 145
 146 pte_t huge_ptep_get(pte_t *ptep)
 147 {
 148         return __rste_to_pte(pte_val(*ptep));
 149 }
 150
 151 pte_t huge_ptep_get_and_clear(struct mm_struct *mm,
 152                               unsigned long addr, pte_t *ptep)
 153 {
 154         pte_t pte = huge_ptep_get(ptep);
 155         pmd_t *pmdp = (pmd_t *) ptep;
 156         pud_t *pudp = (pud_t *) ptep;
 157
 158         if ((pte_val(*ptep) & _REGION_ENTRY_TYPE_MASK) == _REGION_ENTRY_TYPE_R3)
 159                 pudp_xchg_direct(mm, addr, pudp, __pud(_REGION3_ENTRY_EMPTY));
 160         else
 161                 pmdp_xchg_direct(mm, addr, pmdp, __pmd(_SEGMENT_ENTRY_EMPTY));
 162         return pte;
 163 }
 164
 165 pte_t *huge_pte_alloc(struct mm_struct *mm,
 166                         unsigned long addr, unsigned long sz)
 167 {
 168         pgd_t *pgdp;
 169         p4d_t *p4dp;
 170         pud_t *pudp;
 171         pmd_t *pmdp = NULL;
 172
 173         pgdp = pgd_offset(mm, addr);
 174         p4dp = p4d_alloc(mm, pgdp, addr);
 175         if (p4dp) {
 176                 pudp = pud_alloc(mm, p4dp, addr);
 177                 if (pudp) {
 178                         if (sz == PUD_SIZE)
 179                                 return (pte_t *) pudp;
 180                         else if (sz == PMD_SIZE)
 181                                 pmdp = pmd_alloc(mm, pudp, addr);
 182                 }
 183         }
 184         return (pte_t *) pmdp;
 185 }
 186
 187 pte_t *huge_pte_offset(struct mm_struct *mm,
 188                        unsigned long addr, unsigned long sz)
 189 {
 190         pgd_t *pgdp;
 191         p4d_t *p4dp;
 192         pud_t *pudp;
 193         pmd_t *pmdp = NULL;
 194
 195         pgdp = pgd_offset(mm, addr);
 196         if (pgd_present(*pgdp)) {
 197                 p4dp = p4d_offset(pgdp, addr);
 198                 if (p4d_present(*p4dp)) {
 199                         pudp = pud_offset(p4dp, addr);
 200                         if (pud_present(*pudp)) {
 201                                 if (pud_large(*pudp))
 202                                         return (pte_t *) pudp;
 203                                 pmdp = pmd_offset(pudp, addr);
 204                         }
 205                 }
 206         }
 207         return (pte_t *) pmdp;
 208 }
 209
 210 int pmd_huge(pmd_t pmd)
 211 {
 212         return pmd_large(pmd);
 213 }
 214
 215 int pud_huge(pud_t pud)
 216 {
 217         return pud_large(pud);
 218 }
 219
 220 struct page *
 221 follow_huge_pud(struct mm_struct *mm, unsigned long address,
 222                 pud_t *pud, int flags)
 223 {
 224         if (flags & FOLL_GET)
 225                 return NULL;
 226
 227         return pud_page(*pud) + ((address & ~PUD_MASK) >> PAGE_SHIFT);
 228 }
 229
 230 static __init int setup_hugepagesz(char *opt)
 231 {
 232         unsigned long size;
 233         char *string = opt;
 234
 235         size = memparse(opt, &opt);
 236         if (MACHINE_HAS_EDAT1 && size == PMD_SIZE) {
 237                 hugetlb_add_hstate(PMD_SHIFT - PAGE_SHIFT);
 238         } else if (MACHINE_HAS_EDAT2 && size == PUD_SIZE) {
 239                 hugetlb_add_hstate(PUD_SHIFT - PAGE_SHIFT);
 240         } else {
 241                 hugetlb_bad_size();
 242                 pr_err("hugepagesz= specifies an unsupported page size %s\n",
 243                         string);
 244                 return 0;
 245         }
 246         return 1;
 247 }
 248 __setup("hugepagesz=", setup_hugepagesz);
 249
 250 static unsigned long hugetlb_get_unmapped_area_bottomup(struct file *file,
 251                 unsigned long addr, unsigned long len,
 252                 unsigned long pgoff, unsigned long flags)
 253 {
 254         struct hstate *h = hstate_file(file);
 255         struct vm_unmapped_area_info info;
 256
 257         info.flags = 0;
 258         info.length = len;
 259         info.low_limit = current->mm->mmap_base;
 260         info.high_limit = TASK_SIZE;
 261         info.align_mask = PAGE_MASK & ~huge_page_mask(h);
 262         info.align_offset = 0;
 263         return vm_unmapped_area(&info);
 264 }
 265
 266 static unsigned long hugetlb_get_unmapped_area_topdown(struct file *file,
 267                 unsigned long addr0, unsigned long len,
 268                 unsigned long pgoff, unsigned long flags)
 269 {
 270         struct hstate *h = hstate_file(file);
 271         struct vm_unmapped_area_info info;
 272         unsigned long addr;
 273
 274         info.flags = VM_UNMAPPED_AREA_TOPDOWN;
 275         info.length = len;
 276         info.low_limit = max(PAGE_SIZE, mmap_min_addr);
 277         info.high_limit = current->mm->mmap_base;
 278         info.align_mask = PAGE_MASK & ~huge_page_mask(h);
 279         info.align_offset = 0;
 280         addr = vm_unmapped_area(&info);
 281
 282         /*
 283          * A failed mmap() very likely causes application failure,
 284          * so fall back to the bottom-up function here. This scenario
 285          * can happen with large stack limits and large mmap()
 286          * allocations.
 287          */
 288         if (addr & ~PAGE_MASK) {
 289                 VM_BUG_ON(addr != -ENOMEM);
 290                 info.flags = 0;
 291                 info.low_limit = TASK_UNMAPPED_BASE;
 292                 info.high_limit = TASK_SIZE;
 293                 addr = vm_unmapped_area(&info);
 294         }
 295
 296         return addr;
 297 }
 298
 299 unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
 300                 unsigned long len, unsigned long pgoff, unsigned long flags)
 301 {
 302         struct hstate *h = hstate_file(file);
 303         struct mm_struct *mm = current->mm;
 304         struct vm_area_struct *vma;
 305         int rc;
 306
 307         if (len & ~huge_page_mask(h))
 308                 return -EINVAL;
 309         if (len > TASK_SIZE - mmap_min_addr)
 310                 return -ENOMEM;
 311
 312         if (flags & MAP_FIXED) {
 313                 if (prepare_hugepage_range(file, addr, len))
 314                         return -EINVAL;
 315                 goto check_asce_limit;
 316         }
 317
 318         if (addr) {
 319                 addr = ALIGN(addr, huge_page_size(h));
 320                 vma = find_vma(mm, addr);
 321                 if (TASK_SIZE - len >= addr && addr >= mmap_min_addr &&
 322                     (!vma || addr + len <= vm_start_gap(vma)))
 323                         goto check_asce_limit;
 324         }
 325
 326         if (mm->get_unmapped_area == arch_get_unmapped_area)
 327                 addr = hugetlb_get_unmapped_area_bottomup(file, addr, len,
 328                                 pgoff, flags);
 329         else
 330                 addr = hugetlb_get_unmapped_area_topdown(file, addr, len,
 331                                 pgoff, flags);
 332         if (addr & ~PAGE_MASK)
 333                 return addr;
 334
 335 check_asce_limit:
 336         if (addr + len > current->mm->context.asce_limit &&
 337             addr + len <= TASK_SIZE) {
 338                 rc = crst_table_upgrade(mm, addr + len);
 339                 if (rc)
 340                         return (unsigned long) rc;
 341         }
 342         return addr;
 343 }