arch/metag/mm/hugetlbpage.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * arch/metag/mm/hugetlbpage.c
   4  *
   5  * METAG HugeTLB page support.
   6  *
   7  * Cloned from SuperH
   8  *
   9  * Cloned from sparc64 by Paul Mundt.
  10  *
  11  * Copyright (C) 2002, 2003 David S. Miller (davem@redhat.com)
  12  */
  13
  14 #include <linux/init.h>
  15 #include <linux/fs.h>
  16 #include <linux/mm.h>
  17 #include <linux/hugetlb.h>
  18 #include <linux/pagemap.h>
  19 #include <linux/sysctl.h>
  20
  21 #include <asm/mman.h>
  22 #include <asm/pgalloc.h>
  23 #include <asm/tlb.h>
  24 #include <asm/tlbflush.h>
  25 #include <asm/cacheflush.h>
  26
  27 /*
  28  * If the arch doesn't supply something else, assume that hugepage
  29  * size aligned regions are ok without further preparation.
  30  */
  31 int prepare_hugepage_range(struct file *file, unsigned long addr,
  32                                                 unsigned long len)
  33 {
  34         struct mm_struct *mm = current->mm;
  35         struct hstate *h = hstate_file(file);
  36         struct vm_area_struct *vma;
  37
  38         if (len & ~huge_page_mask(h))
  39                 return -EINVAL;
  40         if (addr & ~huge_page_mask(h))
  41                 return -EINVAL;
  42         if (TASK_SIZE - len < addr)
  43                 return -EINVAL;
  44
  45         vma = find_vma(mm, ALIGN_HUGEPT(addr));
  46         if (vma && !(vma->vm_flags & MAP_HUGETLB))
  47                 return -EINVAL;
  48
  49         vma = find_vma(mm, addr);
  50         if (vma) {
  51                 if (addr + len > vma->vm_start)
  52                         return -EINVAL;
  53                 if (!(vma->vm_flags & MAP_HUGETLB) &&
  54                     (ALIGN_HUGEPT(addr + len) > vma->vm_start))
  55                         return -EINVAL;
  56         }
  57         return 0;
  58 }
  59
  60 pte_t *huge_pte_alloc(struct mm_struct *mm,
  61                         unsigned long addr, unsigned long sz)
  62 {
  63         pgd_t *pgd;
  64         pud_t *pud;
  65         pmd_t *pmd;
  66         pte_t *pte;
  67
  68         pgd = pgd_offset(mm, addr);
  69         pud = pud_offset(pgd, addr);
  70         pmd = pmd_offset(pud, addr);
  71         pte = pte_alloc_map(mm, pmd, addr);
  72         pgd->pgd &= ~_PAGE_SZ_MASK;
  73         pgd->pgd |= _PAGE_SZHUGE;
  74
  75         return pte;
  76 }
  77
  78 pte_t *huge_pte_offset(struct mm_struct *mm,
  79                        unsigned long addr, unsigned long sz)
  80 {
  81         pgd_t *pgd;
  82         pud_t *pud;
  83         pmd_t *pmd;
  84         pte_t *pte = NULL;
  85
  86         pgd = pgd_offset(mm, addr);
  87         pud = pud_offset(pgd, addr);
  88         pmd = pmd_offset(pud, addr);
  89         pte = pte_offset_kernel(pmd, addr);
  90
  91         return pte;
  92 }
  93
  94 int pmd_huge(pmd_t pmd)
  95 {
  96         return pmd_page_shift(pmd) > PAGE_SHIFT;
  97 }
  98
  99 int pud_huge(pud_t pud)
 100 {
 101         return 0;
 102 }
 103
 104 struct page *follow_huge_pmd(struct mm_struct *mm, unsigned long address,
 105                              pmd_t *pmd, int write)
 106 {
 107         return NULL;
 108 }
 109
 110 #ifdef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
 111
 112 /*
 113  * Look for an unmapped area starting after another hugetlb vma.
 114  * There are guaranteed to be no huge pte's spare if all the huge pages are
 115  * full size (4MB), so in that case compile out this search.
 116  */
 117 #if HPAGE_SHIFT == HUGEPT_SHIFT
 118 static inline unsigned long
 119 hugetlb_get_unmapped_area_existing(unsigned long len)
 120 {
 121         return 0;
 122 }
 123 #else
 124 static unsigned long
 125 hugetlb_get_unmapped_area_existing(unsigned long len)
 126 {
 127         struct mm_struct *mm = current->mm;
 128         struct vm_area_struct *vma;
 129         unsigned long start_addr, addr;
 130         int after_huge;
 131
 132         if (mm->context.part_huge) {
 133                 start_addr = mm->context.part_huge;
 134                 after_huge = 1;
 135         } else {
 136                 start_addr = TASK_UNMAPPED_BASE;
 137                 after_huge = 0;
 138         }
 139 new_search:
 140         addr = start_addr;
 141
 142         for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
 143                 if ((!vma && !after_huge) || TASK_SIZE - len < addr) {
 144                         /*
 145                          * Start a new search - just in case we missed
 146                          * some holes.
 147                          */
 148                         if (start_addr != TASK_UNMAPPED_BASE) {
 149                                 start_addr = TASK_UNMAPPED_BASE;
 150                                 goto new_search;
 151                         }
 152                         return 0;
 153                 }
 154                 /* skip ahead if we've aligned right over some vmas */
 155                 if (vma && vma->vm_end <= addr)
 156                         continue;
 157                 /* space before the next vma? */
 158                 if (after_huge && (!vma || ALIGN_HUGEPT(addr + len)
 159                             <= vma->vm_start)) {
 160                         unsigned long end = addr + len;
 161                         if (end & HUGEPT_MASK)
 162                                 mm->context.part_huge = end;
 163                         else if (addr == mm->context.part_huge)
 164                                 mm->context.part_huge = 0;
 165                         return addr;
 166                 }
 167                 if (vma->vm_flags & MAP_HUGETLB) {
 168                         /* space after a huge vma in 2nd level page table? */
 169                         if (vma->vm_end & HUGEPT_MASK) {
 170                                 after_huge = 1;
 171                                 /* no need to align to the next PT block */
 172                                 addr = vma->vm_end;
 173                                 continue;
 174                         }
 175                 }
 176                 after_huge = 0;
 177                 addr = ALIGN_HUGEPT(vma->vm_end);
 178         }
 179 }
 180 #endif
 181
 182 /* Do a full search to find an area without any nearby normal pages. */
 183 static unsigned long
 184 hugetlb_get_unmapped_area_new_pmd(unsigned long len)
 185 {
 186         struct vm_unmapped_area_info info;
 187
 188         info.flags = 0;
 189         info.length = len;
 190         info.low_limit = TASK_UNMAPPED_BASE;
 191         info.high_limit = TASK_SIZE;
 192         info.align_mask = PAGE_MASK & HUGEPT_MASK;
 193         info.align_offset = 0;
 194         return vm_unmapped_area(&info);
 195 }
 196
 197 unsigned long
 198 hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
 199                 unsigned long len, unsigned long pgoff, unsigned long flags)
 200 {
 201         struct hstate *h = hstate_file(file);
 202
 203         if (len & ~huge_page_mask(h))
 204                 return -EINVAL;
 205         if (len > TASK_SIZE)
 206                 return -ENOMEM;
 207
 208         if (flags & MAP_FIXED) {
 209                 if (prepare_hugepage_range(file, addr, len))
 210                         return -EINVAL;
 211                 return addr;
 212         }
 213
 214         if (addr) {
 215                 addr = ALIGN(addr, huge_page_size(h));
 216                 if (!prepare_hugepage_range(file, addr, len))
 217                         return addr;
 218         }
 219
 220         /*
 221          * Look for an existing hugetlb vma with space after it (this is to to
 222          * minimise fragmentation caused by huge pages.
 223          */
 224         addr = hugetlb_get_unmapped_area_existing(len);
 225         if (addr)
 226                 return addr;
 227
 228         /*
 229          * Find an unmapped naturally aligned set of 4MB blocks that we can use
 230          * for huge pages.
 231          */
 232         return hugetlb_get_unmapped_area_new_pmd(len);
 233 }
 234
 235 #endif /*HAVE_ARCH_HUGETLB_UNMAPPED_AREA*/
 236
 237 /* necessary for boot time 4MB huge page allocation */
 238 static __init int setup_hugepagesz(char *opt)
 239 {
 240         unsigned long ps = memparse(opt, &opt);
 241         if (ps == (1 << HPAGE_SHIFT)) {
 242                 hugetlb_add_hstate(HPAGE_SHIFT - PAGE_SHIFT);
 243         } else {
 244                 hugetlb_bad_size();
 245                 pr_err("hugepagesz: Unsupported page size %lu M\n",
 246                        ps >> 20);
 247                 return 0;
 248         }
 249         return 1;
 250 }
 251 __setup("hugepagesz=", setup_hugepagesz);