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 int pmd_huge_support(void)
 114 {
 115         return 1;
 116 }
 117
 118 struct page *follow_huge_pmd(struct mm_struct *mm, unsigned long address,
 119                              pmd_t *pmd, int write)
 120 {
 121         return NULL;
 122 }
 123
 124 #ifdef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
 125
 126 /*
 127  * Look for an unmapped area starting after another hugetlb vma.
 128  * There are guaranteed to be no huge pte's spare if all the huge pages are
 129  * full size (4MB), so in that case compile out this search.
 130  */
 131 #if HPAGE_SHIFT == HUGEPT_SHIFT
 132 static inline unsigned long
 133 hugetlb_get_unmapped_area_existing(unsigned long len)
 134 {
 135         return 0;
 136 }
 137 #else
 138 static unsigned long
 139 hugetlb_get_unmapped_area_existing(unsigned long len)
 140 {
 141         struct mm_struct *mm = current->mm;
 142         struct vm_area_struct *vma;
 143         unsigned long start_addr, addr;
 144         int after_huge;
 145
 146         if (mm->context.part_huge) {
 147                 start_addr = mm->context.part_huge;
 148                 after_huge = 1;
 149         } else {
 150                 start_addr = TASK_UNMAPPED_BASE;
 151                 after_huge = 0;
 152         }
 153 new_search:
 154         addr = start_addr;
 155
 156         for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
 157                 if ((!vma && !after_huge) || TASK_SIZE - len < addr) {
 158                         /*
 159                          * Start a new search - just in case we missed
 160                          * some holes.
 161                          */
 162                         if (start_addr != TASK_UNMAPPED_BASE) {
 163                                 start_addr = TASK_UNMAPPED_BASE;
 164                                 goto new_search;
 165                         }
 166                         return 0;
 167                 }
 168                 /* skip ahead if we've aligned right over some vmas */
 169                 if (vma && vma->vm_end <= addr)
 170                         continue;
 171                 /* space before the next vma? */
 172                 if (after_huge && (!vma || ALIGN_HUGEPT(addr + len)
 173                             <= vma->vm_start)) {
 174                         unsigned long end = addr + len;
 175                         if (end & HUGEPT_MASK)
 176                                 mm->context.part_huge = end;
 177                         else if (addr == mm->context.part_huge)
 178                                 mm->context.part_huge = 0;
 179                         return addr;
 180                 }
 181                 if (vma && (vma->vm_flags & MAP_HUGETLB)) {
 182                         /* space after a huge vma in 2nd level page table? */
 183                         if (vma->vm_end & HUGEPT_MASK) {
 184                                 after_huge = 1;
 185                                 /* no need to align to the next PT block */
 186                                 addr = vma->vm_end;
 187                                 continue;
 188                         }
 189                 }
 190                 after_huge = 0;
 191                 addr = ALIGN_HUGEPT(vma->vm_end);
 192         }
 193 }
 194 #endif
 195
 196 /* Do a full search to find an area without any nearby normal pages. */
 197 static unsigned long
 198 hugetlb_get_unmapped_area_new_pmd(unsigned long len)
 199 {
 200         struct vm_unmapped_area_info info;
 201
 202         info.flags = 0;
 203         info.length = len;
 204         info.low_limit = TASK_UNMAPPED_BASE;
 205         info.high_limit = TASK_SIZE;
 206         info.align_mask = PAGE_MASK & HUGEPT_MASK;
 207         info.align_offset = 0;
 208         return vm_unmapped_area(&info);
 209 }
 210
 211 unsigned long
 212 hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
 213                 unsigned long len, unsigned long pgoff, unsigned long flags)
 214 {
 215         struct hstate *h = hstate_file(file);
 216
 217         if (len & ~huge_page_mask(h))
 218                 return -EINVAL;
 219         if (len > TASK_SIZE)
 220                 return -ENOMEM;
 221
 222         if (flags & MAP_FIXED) {
 223                 if (prepare_hugepage_range(file, addr, len))
 224                         return -EINVAL;
 225                 return addr;
 226         }
 227
 228         if (addr) {
 229                 addr = ALIGN(addr, huge_page_size(h));
 230                 if (!prepare_hugepage_range(file, addr, len))
 231                         return addr;
 232         }
 233
 234         /*
 235          * Look for an existing hugetlb vma with space after it (this is to to
 236          * minimise fragmentation caused by huge pages.
 237          */
 238         addr = hugetlb_get_unmapped_area_existing(len);
 239         if (addr)
 240                 return addr;
 241
 242         /*
 243          * Find an unmapped naturally aligned set of 4MB blocks that we can use
 244          * for huge pages.
 245          */
 246         return hugetlb_get_unmapped_area_new_pmd(len);
 247 }
 248
 249 #endif /*HAVE_ARCH_HUGETLB_UNMAPPED_AREA*/
 250
 251 /* necessary for boot time 4MB huge page allocation */
 252 static __init int setup_hugepagesz(char *opt)
 253 {
 254         unsigned long ps = memparse(opt, &opt);
 255         if (ps == (1 << HPAGE_SHIFT)) {
 256                 hugetlb_add_hstate(HPAGE_SHIFT - PAGE_SHIFT);
 257         } else {
 258                 pr_err("hugepagesz: Unsupported page size %lu M\n",
 259                        ps >> 20);
 260                 return 0;
 261         }
 262         return 1;
 263 }
 264 __setup("hugepagesz=", setup_hugepagesz);