kernel/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 int pmd_huge(pmd_t pmd)
  98 {
  99         return pmd_page_shift(pmd) > PAGE_SHIFT;
 100 }
 101
 102 int pud_huge(pud_t pud)
 103 {
 104         return 0;
 105 }
 106
 107 struct page *follow_huge_pmd(struct mm_struct *mm, unsigned long address,
 108                              pmd_t *pmd, int write)
 109 {
 110         return NULL;
 111 }
 112
 113 #ifdef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
 114
 115 /*
 116  * Look for an unmapped area starting after another hugetlb vma.
 117  * There are guaranteed to be no huge pte's spare if all the huge pages are
 118  * full size (4MB), so in that case compile out this search.
 119  */
 120 #if HPAGE_SHIFT == HUGEPT_SHIFT
 121 static inline unsigned long
 122 hugetlb_get_unmapped_area_existing(unsigned long len)
 123 {
 124         return 0;
 125 }
 126 #else
 127 static unsigned long
 128 hugetlb_get_unmapped_area_existing(unsigned long len)
 129 {
 130         struct mm_struct *mm = current->mm;
 131         struct vm_area_struct *vma;
 132         unsigned long start_addr, addr;
 133         int after_huge;
 134
 135         if (mm->context.part_huge) {
 136                 start_addr = mm->context.part_huge;
 137                 after_huge = 1;
 138         } else {
 139                 start_addr = TASK_UNMAPPED_BASE;
 140                 after_huge = 0;
 141         }
 142 new_search:
 143         addr = start_addr;
 144
 145         for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
 146                 if ((!vma && !after_huge) || TASK_SIZE - len < addr) {
 147                         /*
 148                          * Start a new search - just in case we missed
 149                          * some holes.
 150                          */
 151                         if (start_addr != TASK_UNMAPPED_BASE) {
 152                                 start_addr = TASK_UNMAPPED_BASE;
 153                                 goto new_search;
 154                         }
 155                         return 0;
 156                 }
 157                 /* skip ahead if we've aligned right over some vmas */
 158                 if (vma && vma->vm_end <= addr)
 159                         continue;
 160                 /* space before the next vma? */
 161                 if (after_huge && (!vma || ALIGN_HUGEPT(addr + len)
 162                             <= vma->vm_start)) {
 163                         unsigned long end = addr + len;
 164                         if (end & HUGEPT_MASK)
 165                                 mm->context.part_huge = end;
 166                         else if (addr == mm->context.part_huge)
 167                                 mm->context.part_huge = 0;
 168                         return addr;
 169                 }
 170                 if (vma->vm_flags & MAP_HUGETLB) {
 171                         /* space after a huge vma in 2nd level page table? */
 172                         if (vma->vm_end & HUGEPT_MASK) {
 173                                 after_huge = 1;
 174                                 /* no need to align to the next PT block */
 175                                 addr = vma->vm_end;
 176                                 continue;
 177                         }
 178                 }
 179                 after_huge = 0;
 180                 addr = ALIGN_HUGEPT(vma->vm_end);
 181         }
 182 }
 183 #endif
 184
 185 /* Do a full search to find an area without any nearby normal pages. */
 186 static unsigned long
 187 hugetlb_get_unmapped_area_new_pmd(unsigned long len)
 188 {
 189         struct vm_unmapped_area_info info;
 190
 191         info.flags = 0;
 192         info.length = len;
 193         info.low_limit = TASK_UNMAPPED_BASE;
 194         info.high_limit = TASK_SIZE;
 195         info.align_mask = PAGE_MASK & HUGEPT_MASK;
 196         info.align_offset = 0;
 197         return vm_unmapped_area(&info);
 198 }
 199
 200 unsigned long
 201 hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
 202                 unsigned long len, unsigned long pgoff, unsigned long flags)
 203 {
 204         struct hstate *h = hstate_file(file);
 205
 206         if (len & ~huge_page_mask(h))
 207                 return -EINVAL;
 208         if (len > TASK_SIZE)
 209                 return -ENOMEM;
 210
 211         if (flags & MAP_FIXED) {
 212                 if (prepare_hugepage_range(file, addr, len))
 213                         return -EINVAL;
 214                 return addr;
 215         }
 216
 217         if (addr) {
 218                 addr = ALIGN(addr, huge_page_size(h));
 219                 if (!prepare_hugepage_range(file, addr, len))
 220                         return addr;
 221         }
 222
 223         /*
 224          * Look for an existing hugetlb vma with space after it (this is to to
 225          * minimise fragmentation caused by huge pages.
 226          */
 227         addr = hugetlb_get_unmapped_area_existing(len);
 228         if (addr)
 229                 return addr;
 230
 231         /*
 232          * Find an unmapped naturally aligned set of 4MB blocks that we can use
 233          * for huge pages.
 234          */
 235         return hugetlb_get_unmapped_area_new_pmd(len);
 236 }
 237
 238 #endif /*HAVE_ARCH_HUGETLB_UNMAPPED_AREA*/
 239
 240 /* necessary for boot time 4MB huge page allocation */
 241 static __init int setup_hugepagesz(char *opt)
 242 {
 243         unsigned long ps = memparse(opt, &opt);
 244         if (ps == (1 << HPAGE_SHIFT)) {
 245                 hugetlb_add_hstate(HPAGE_SHIFT - PAGE_SHIFT);
 246         } else {
 247                 pr_err("hugepagesz: Unsupported page size %lu M\n",
 248                        ps >> 20);
 249                 return 0;
 250         }
 251         return 1;
 252 }
 253 __setup("hugepagesz=", setup_hugepagesz);