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 pte_t huge_ptep_get(pte_t *ptep)
 167 {
 168         return __rste_to_pte(pte_val(*ptep));
 169 }
 170
 171 pte_t huge_ptep_get_and_clear(struct mm_struct *mm,
 172                               unsigned long addr, pte_t *ptep)
 173 {
 174         pte_t pte = huge_ptep_get(ptep);
 175         pmd_t *pmdp = (pmd_t *) ptep;
 176         pud_t *pudp = (pud_t *) ptep;
 177
 178         if ((pte_val(*ptep) & _REGION_ENTRY_TYPE_MASK) == _REGION_ENTRY_TYPE_R3)
 179                 pudp_xchg_direct(mm, addr, pudp, __pud(_REGION3_ENTRY_EMPTY));
 180         else
 181                 pmdp_xchg_direct(mm, addr, pmdp, __pmd(_SEGMENT_ENTRY_EMPTY));
 182         return pte;
 183 }
 184
 185 pte_t *huge_pte_alloc(struct mm_struct *mm, struct vm_area_struct *vma,
 186                         unsigned long addr, unsigned long sz)
 187 {
 188         pgd_t *pgdp;
 189         p4d_t *p4dp;
 190         pud_t *pudp;
 191         pmd_t *pmdp = NULL;
 192
 193         pgdp = pgd_offset(mm, addr);
 194         p4dp = p4d_alloc(mm, pgdp, addr);
 195         if (p4dp) {
 196                 pudp = pud_alloc(mm, p4dp, addr);
 197                 if (pudp) {
 198                         if (sz == PUD_SIZE)
 199                                 return (pte_t *) pudp;
 200                         else if (sz == PMD_SIZE)
 201                                 pmdp = pmd_alloc(mm, pudp, addr);
 202                 }
 203         }
 204         return (pte_t *) pmdp;
 205 }
 206
 207 pte_t *huge_pte_offset(struct mm_struct *mm,
 208                        unsigned long addr, unsigned long sz)
 209 {
 210         pgd_t *pgdp;
 211         p4d_t *p4dp;
 212         pud_t *pudp;
 213         pmd_t *pmdp = NULL;
 214
 215         pgdp = pgd_offset(mm, addr);
 216         if (pgd_present(*pgdp)) {
 217                 p4dp = p4d_offset(pgdp, addr);
 218                 if (p4d_present(*p4dp)) {
 219                         pudp = pud_offset(p4dp, addr);
 220                         if (pud_present(*pudp)) {
 221                                 if (pud_large(*pudp))
 222                                         return (pte_t *) pudp;
 223                                 pmdp = pmd_offset(pudp, addr);
 224                         }
 225                 }
 226         }
 227         return (pte_t *) pmdp;
 228 }
 229
 230 int pmd_huge(pmd_t pmd)
 231 {
 232         return pmd_large(pmd);
 233 }
 234
 235 int pud_huge(pud_t pud)
 236 {
 237         return pud_large(pud);
 238 }
 239
 240 bool __init arch_hugetlb_valid_size(unsigned long size)
 241 {
 242         if (MACHINE_HAS_EDAT1 && size == PMD_SIZE)
 243                 return true;
 244         else if (MACHINE_HAS_EDAT2 && size == PUD_SIZE)
 245                 return true;
 246         else
 247                 return false;
 248 }
 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
 306         if (len & ~huge_page_mask(h))
 307                 return -EINVAL;
 308         if (len > TASK_SIZE - mmap_min_addr)
 309                 return -ENOMEM;
 310
 311         if (flags & MAP_FIXED) {
 312                 if (prepare_hugepage_range(file, addr, len))
 313                         return -EINVAL;
 314                 goto check_asce_limit;
 315         }
 316
 317         if (addr) {
 318                 addr = ALIGN(addr, huge_page_size(h));
 319                 vma = find_vma(mm, addr);
 320                 if (TASK_SIZE - len >= addr && addr >= mmap_min_addr &&
 321                     (!vma || addr + len <= vm_start_gap(vma)))
 322                         goto check_asce_limit;
 323         }
 324
 325         if (mm->get_unmapped_area == arch_get_unmapped_area)
 326                 addr = hugetlb_get_unmapped_area_bottomup(file, addr, len,
 327                                 pgoff, flags);
 328         else
 329                 addr = hugetlb_get_unmapped_area_topdown(file, addr, len,
 330                                 pgoff, flags);
 331         if (offset_in_page(addr))
 332                 return addr;
 333
 334 check_asce_limit:
 335         return check_asce_limit(mm, addr, len);
 336 }