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, 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,
  78                        unsigned long addr, unsigned long sz)
  79 {
  80         pgd_t *pgd;
  81         pud_t *pud;
  82         pmd_t *pmd;
  83         pte_t *pte = NULL;
  84
  85         pgd = pgd_offset(mm, addr);
  86         pud = pud_offset(pgd, addr);
  87         pmd = pmd_offset(pud, addr);
  88         pte = pte_offset_kernel(pmd, addr);
  89
  90         return pte;
  91 }
  92
  93 int pmd_huge(pmd_t pmd)
  94 {
  95         return pmd_page_shift(pmd) > PAGE_SHIFT;
  96 }
  97
  98 int pud_huge(pud_t pud)
  99 {
 100         return 0;
 101 }
 102
 103 struct page *follow_huge_pmd(struct mm_struct *mm, unsigned long address,
 104                              pmd_t *pmd, int write)
 105 {
 106         return NULL;
 107 }
 108
 109 #ifdef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
 110
 111 /*
 112  * Look for an unmapped area starting after another hugetlb vma.
 113  * There are guaranteed to be no huge pte's spare if all the huge pages are
 114  * full size (4MB), so in that case compile out this search.
 115  */
 116 #if HPAGE_SHIFT == HUGEPT_SHIFT
 117 static inline unsigned long
 118 hugetlb_get_unmapped_area_existing(unsigned long len)
 119 {
 120         return 0;
 121 }
 122 #else
 123 static unsigned long
 124 hugetlb_get_unmapped_area_existing(unsigned long len)
 125 {
 126         struct mm_struct *mm = current->mm;
 127         struct vm_area_struct *vma;
 128         unsigned long start_addr, addr;
 129         int after_huge;
 130
 131         if (mm->context.part_huge) {
 132                 start_addr = mm->context.part_huge;
 133                 after_huge = 1;
 134         } else {
 135                 start_addr = TASK_UNMAPPED_BASE;
 136                 after_huge = 0;
 137         }
 138 new_search:
 139         addr = start_addr;
 140
 141         for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
 142                 if ((!vma && !after_huge) || TASK_SIZE - len < addr) {
 143                         /*
 144                          * Start a new search - just in case we missed
 145                          * some holes.
 146                          */
 147                         if (start_addr != TASK_UNMAPPED_BASE) {
 148                                 start_addr = TASK_UNMAPPED_BASE;
 149                                 goto new_search;
 150                         }
 151                         return 0;
 152                 }
 153                 /* skip ahead if we've aligned right over some vmas */
 154                 if (vma && vma->vm_end <= addr)
 155                         continue;
 156                 /* space before the next vma? */
 157                 if (after_huge && (!vma || ALIGN_HUGEPT(addr + len)
 158                             <= vma->vm_start)) {
 159                         unsigned long end = addr + len;
 160                         if (end & HUGEPT_MASK)
 161                                 mm->context.part_huge = end;
 162                         else if (addr == mm->context.part_huge)
 163                                 mm->context.part_huge = 0;
 164                         return addr;
 165                 }
 166                 if (vma->vm_flags & MAP_HUGETLB) {
 167                         /* space after a huge vma in 2nd level page table? */
 168                         if (vma->vm_end & HUGEPT_MASK) {
 169                                 after_huge = 1;
 170                                 /* no need to align to the next PT block */
 171                                 addr = vma->vm_end;
 172                                 continue;
 173                         }
 174                 }
 175                 after_huge = 0;
 176                 addr = ALIGN_HUGEPT(vma->vm_end);
 177         }
 178 }
 179 #endif
 180
 181 /* Do a full search to find an area without any nearby normal pages. */
 182 static unsigned long
 183 hugetlb_get_unmapped_area_new_pmd(unsigned long len)
 184 {
 185         struct vm_unmapped_area_info info;
 186
 187         info.flags = 0;
 188         info.length = len;
 189         info.low_limit = TASK_UNMAPPED_BASE;
 190         info.high_limit = TASK_SIZE;
 191         info.align_mask = PAGE_MASK & HUGEPT_MASK;
 192         info.align_offset = 0;
 193         return vm_unmapped_area(&info);
 194 }
 195
 196 unsigned long
 197 hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
 198                 unsigned long len, unsigned long pgoff, unsigned long flags)
 199 {
 200         struct hstate *h = hstate_file(file);
 201
 202         if (len & ~huge_page_mask(h))
 203                 return -EINVAL;
 204         if (len > TASK_SIZE)
 205                 return -ENOMEM;
 206
 207         if (flags & MAP_FIXED) {
 208                 if (prepare_hugepage_range(file, addr, len))
 209                         return -EINVAL;
 210                 return addr;
 211         }
 212
 213         if (addr) {
 214                 addr = ALIGN(addr, huge_page_size(h));
 215                 if (!prepare_hugepage_range(file, addr, len))
 216                         return addr;
 217         }
 218
 219         /*
 220          * Look for an existing hugetlb vma with space after it (this is to to
 221          * minimise fragmentation caused by huge pages.
 222          */
 223         addr = hugetlb_get_unmapped_area_existing(len);
 224         if (addr)
 225                 return addr;
 226
 227         /*
 228          * Find an unmapped naturally aligned set of 4MB blocks that we can use
 229          * for huge pages.
 230          */
 231         return hugetlb_get_unmapped_area_new_pmd(len);
 232 }
 233
 234 #endif /*HAVE_ARCH_HUGETLB_UNMAPPED_AREA*/
 235
 236 /* necessary for boot time 4MB huge page allocation */
 237 static __init int setup_hugepagesz(char *opt)
 238 {
 239         unsigned long ps = memparse(opt, &opt);
 240         if (ps == (1 << HPAGE_SHIFT)) {
 241                 hugetlb_add_hstate(HPAGE_SHIFT - PAGE_SHIFT);
 242         } else {
 243                 hugetlb_bad_size();
 244                 pr_err("hugepagesz: Unsupported page size %lu M\n",
 245                        ps >> 20);
 246                 return 0;
 247         }
 248         return 1;
 249 }
 250 __setup("hugepagesz=", setup_hugepagesz);