arch/metag/mm/hugetlbpage.c

   1 /*
   2  * arch/metag/mm/hugetlbpage.c
   3  *
   4  * METAG HugeTLB page support.
   5  *
   6  * Cloned from SuperH
   7  *
   8  * Cloned from sparc64 by Paul Mundt.
   9  *
  10  * Copyright (C) 2002, 2003 David S. Miller (davem@redhat.com)
  11  */
  12
  13 #include <linux/init.h>
  14 #include <linux/fs.h>
  15 #include <linux/mm.h>
  16 #include <linux/hugetlb.h>
  17 #include <linux/pagemap.h>
  18 #include <linux/sysctl.h>
  19
  20 #include <asm/mman.h>
  21 #include <asm/pgalloc.h>
  22 #include <asm/tlb.h>
  23 #include <asm/tlbflush.h>
  24 #include <asm/cacheflush.h>
  25
  26 /*
  27  * If the arch doesn't supply something else, assume that hugepage
  28  * size aligned regions are ok without further preparation.
  29  */
  30 int prepare_hugepage_range(struct file *file, unsigned long addr,
  31                                                 unsigned long len)
  32 {
  33         struct mm_struct *mm = current->mm;
  34         struct hstate *h = hstate_file(file);
  35         struct vm_area_struct *vma;
  36
  37         if (len & ~huge_page_mask(h))
  38                 return -EINVAL;
  39         if (addr & ~huge_page_mask(h))
  40                 return -EINVAL;
  41         if (TASK_SIZE - len < addr)
  42                 return -EINVAL;
  43
  44         vma = find_vma(mm, ALIGN_HUGEPT(addr));
  45         if (vma && !(vma->vm_flags & MAP_HUGETLB))
  46                 return -EINVAL;
  47
  48         vma = find_vma(mm, addr);
  49         if (vma) {
  50                 if (addr + len > vma->vm_start)
  51                         return -EINVAL;
  52                 if (!(vma->vm_flags & MAP_HUGETLB) &&
  53                     (ALIGN_HUGEPT(addr + len) > vma->vm_start))
  54                         return -EINVAL;
  55         }
  56         return 0;
  57 }
  58
  59 pte_t *huge_pte_alloc(struct mm_struct *mm,
  60                         unsigned long addr, unsigned long sz)
  61 {
  62         pgd_t *pgd;
  63         pud_t *pud;
  64         pmd_t *pmd;
  65         pte_t *pte;
  66
  67         pgd = pgd_offset(mm, addr);
  68         pud = pud_offset(pgd, addr);
  69         pmd = pmd_offset(pud, addr);
  70         pte = pte_alloc_map(mm, NULL, pmd, addr);
  71         pgd->pgd &= ~_PAGE_SZ_MASK;
  72         pgd->pgd |= _PAGE_SZHUGE;
  73
  74         return pte;
  75 }
  76
  77 pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
  78 {
  79         pgd_t *pgd;
  80         pud_t *pud;
  81         pmd_t *pmd;
  82         pte_t *pte = NULL;
  83
  84         pgd = pgd_offset(mm, addr);
  85         pud = pud_offset(pgd, addr);
  86         pmd = pmd_offset(pud, addr);
  87         pte = pte_offset_kernel(pmd, addr);
  88
  89         return pte;
  90 }
  91
  92 int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
  93 {
  94         return 0;
  95 }
  96
  97 struct page *follow_huge_addr(struct mm_struct *mm,
  98                               unsigned long address, int write)
  99 {
 100         return ERR_PTR(-EINVAL);
 101 }
 102
 103 int pmd_huge(pmd_t pmd)
 104 {
 105         return pmd_page_shift(pmd) > PAGE_SHIFT;
 106 }
 107
 108 int pud_huge(pud_t pud)
 109 {
 110         return 0;
 111 }
 112
 113 struct page *follow_huge_pmd(struct mm_struct *mm, unsigned long address,
 114                              pmd_t *pmd, int write)
 115 {
 116         return NULL;
 117 }
 118
 119 #ifdef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
 120
 121 /*
 122  * Look for an unmapped area starting after another hugetlb vma.
 123  * There are guaranteed to be no huge pte's spare if all the huge pages are
 124  * full size (4MB), so in that case compile out this search.
 125  */
 126 #if HPAGE_SHIFT == HUGEPT_SHIFT
 127 static inline unsigned long
 128 hugetlb_get_unmapped_area_existing(unsigned long len)
 129 {
 130         return 0;
 131 }
 132 #else
 133 static unsigned long
 134 hugetlb_get_unmapped_area_existing(unsigned long len)
 135 {
 136         struct mm_struct *mm = current->mm;
 137         struct vm_area_struct *vma;
 138         unsigned long start_addr, addr;
 139         int after_huge;
 140
 141         if (mm->context.part_huge) {
 142                 start_addr = mm->context.part_huge;
 143                 after_huge = 1;
 144         } else {
 145                 start_addr = TASK_UNMAPPED_BASE;
 146                 after_huge = 0;
 147         }
 148 new_search:
 149         addr = start_addr;
 150
 151         for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
 152                 if ((!vma && !after_huge) || TASK_SIZE - len < addr) {
 153                         /*
 154                          * Start a new search - just in case we missed
 155                          * some holes.
 156                          */
 157                         if (start_addr != TASK_UNMAPPED_BASE) {
 158                                 start_addr = TASK_UNMAPPED_BASE;
 159                                 goto new_search;
 160                         }
 161                         return 0;
 162                 }
 163                 /* skip ahead if we've aligned right over some vmas */
 164                 if (vma && vma->vm_end <= addr)
 165                         continue;
 166                 /* space before the next vma? */
 167                 if (after_huge && (!vma || ALIGN_HUGEPT(addr + len)
 168                             <= vma->vm_start)) {
 169                         unsigned long end = addr + len;
 170                         if (end & HUGEPT_MASK)
 171                                 mm->context.part_huge = end;
 172                         else if (addr == mm->context.part_huge)
 173                                 mm->context.part_huge = 0;
 174                         return addr;
 175                 }
 176                 if (vma && (vma->vm_flags & MAP_HUGETLB)) {
 177                         /* space after a huge vma in 2nd level page table? */
 178                         if (vma->vm_end & HUGEPT_MASK) {
 179                                 after_huge = 1;
 180                                 /* no need to align to the next PT block */
 181                                 addr = vma->vm_end;
 182                                 continue;
 183                         }
 184                 }
 185                 after_huge = 0;
 186                 addr = ALIGN_HUGEPT(vma->vm_end);
 187         }
 188 }
 189 #endif
 190
 191 /* Do a full search to find an area without any nearby normal pages. */
 192 static unsigned long
 193 hugetlb_get_unmapped_area_new_pmd(unsigned long len)
 194 {
 195         struct mm_struct *mm = current->mm;
 196         struct vm_area_struct *vma;
 197         unsigned long start_addr, addr;
 198
 199         if (ALIGN_HUGEPT(len) > mm->cached_hole_size)
 200                 start_addr = mm->free_area_cache;
 201         else
 202                 start_addr = TASK_UNMAPPED_BASE;
 203
 204 new_search:
 205         addr = ALIGN_HUGEPT(start_addr);
 206
 207         for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
 208                 if (TASK_SIZE - len < addr) {
 209                         /*
 210                          * Start a new search - just in case we missed
 211                          * some holes.
 212                          */
 213                         if (start_addr != TASK_UNMAPPED_BASE) {
 214                                 start_addr = TASK_UNMAPPED_BASE;
 215                                 mm->cached_hole_size = 0;
 216                                 goto new_search;
 217                         }
 218                         return 0;
 219                 }
 220                 /* skip ahead if we've aligned right over some vmas */
 221                 if (vma && vma->vm_end <= addr)
 222                         continue;
 223                 if (!vma || ALIGN_HUGEPT(addr + len) <= vma->vm_start) {
 224 #if HPAGE_SHIFT < HUGEPT_SHIFT
 225                         if (len & HUGEPT_MASK)
 226                                 mm->context.part_huge = addr + len;
 227 #endif
 228                         return addr;
 229                 }
 230                 addr = ALIGN_HUGEPT(vma->vm_end);
 231         }
 232 }
 233
 234 unsigned long
 235 hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
 236                 unsigned long len, unsigned long pgoff, unsigned long flags)
 237 {
 238         struct hstate *h = hstate_file(file);
 239
 240         if (len & ~huge_page_mask(h))
 241                 return -EINVAL;
 242         if (len > TASK_SIZE)
 243                 return -ENOMEM;
 244
 245         if (flags & MAP_FIXED) {
 246                 if (prepare_hugepage_range(file, addr, len))
 247                         return -EINVAL;
 248                 return addr;
 249         }
 250
 251         if (addr) {
 252                 addr = ALIGN(addr, huge_page_size(h));
 253                 if (!prepare_hugepage_range(file, addr, len))
 254                         return addr;
 255         }
 256
 257         /*
 258          * Look for an existing hugetlb vma with space after it (this is to to
 259          * minimise fragmentation caused by huge pages.
 260          */
 261         addr = hugetlb_get_unmapped_area_existing(len);
 262         if (addr)
 263                 return addr;
 264
 265         /*
 266          * Find an unmapped naturally aligned set of 4MB blocks that we can use
 267          * for huge pages.
 268          */
 269         addr = hugetlb_get_unmapped_area_new_pmd(len);
 270         if (likely(addr))
 271                 return addr;
 272
 273         return -EINVAL;
 274 }
 275
 276 #endif /*HAVE_ARCH_HUGETLB_UNMAPPED_AREA*/
 277
 278 /* necessary for boot time 4MB huge page allocation */
 279 static __init int setup_hugepagesz(char *opt)
 280 {
 281         unsigned long ps = memparse(opt, &opt);
 282         if (ps == (1 << HPAGE_SHIFT)) {
 283                 hugetlb_add_hstate(HPAGE_SHIFT - PAGE_SHIFT);
 284         } else {
 285                 pr_err("hugepagesz: Unsupported page size %lu M\n",
 286                        ps >> 20);
 287                 return 0;
 288         }
 289         return 1;
 290 }
 291 __setup("hugepagesz=", setup_hugepagesz);