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