arch/sh/mm/hugetlbpage.c

   1 /*
   2  * arch/sh/mm/hugetlbpage.c
   3  *
   4  * SuperH HugeTLB page support.
   5  *
   6  * Cloned from sparc64 by Paul Mundt.
   7  *
   8  * Copyright (C) 2002, 2003 David S. Miller (davem@redhat.com)
   9  */
  10
  11 #include <linux/config.h>
  12 #include <linux/init.h>
  13 #include <linux/fs.h>
  14 #include <linux/mm.h>
  15 #include <linux/hugetlb.h>
  16 #include <linux/pagemap.h>
  17 #include <linux/smp_lock.h>
  18 #include <linux/slab.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 static pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr)
  28 {
  29         pgd_t *pgd;
  30         pmd_t *pmd;
  31         pte_t *pte = NULL;
  32
  33         pgd = pgd_offset(mm, addr);
  34         if (pgd) {
  35                 pmd = pmd_alloc(mm, pgd, addr);
  36                 if (pmd)
  37                         pte = pte_alloc_map(mm, pmd, addr);
  38         }
  39         return pte;
  40 }
  41
  42 static pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
  43 {
  44         pgd_t *pgd;
  45         pmd_t *pmd;
  46         pte_t *pte = NULL;
  47
  48         pgd = pgd_offset(mm, addr);
  49         if (pgd) {
  50                 pmd = pmd_offset(pgd, addr);
  51                 if (pmd)
  52                         pte = pte_offset_map(pmd, addr);
  53         }
  54         return pte;
  55 }
  56
  57 #define mk_pte_huge(entry) do { pte_val(entry) |= _PAGE_SZHUGE; } while (0)
  58
  59 static void set_huge_pte(struct mm_struct *mm, struct vm_area_struct *vma,
  60                          struct page *page, pte_t * page_table, int write_access)
  61 {
  62         unsigned long i;
  63         pte_t entry;
  64
  65         mm->rss += (HPAGE_SIZE / PAGE_SIZE);
  66
  67         if (write_access)
  68                 entry = pte_mkwrite(pte_mkdirty(mk_pte(page,
  69                                                        vma->vm_page_prot)));
  70         else
  71                 entry = pte_wrprotect(mk_pte(page, vma->vm_page_prot));
  72         entry = pte_mkyoung(entry);
  73         mk_pte_huge(entry);
  74
  75         for (i = 0; i < (1 << HUGETLB_PAGE_ORDER); i++) {
  76                 set_pte(page_table, entry);
  77                 page_table++;
  78
  79                 pte_val(entry) += PAGE_SIZE;
  80         }
  81 }
  82
  83 /*
  84  * This function checks for proper alignment of input addr and len parameters.
  85  */
  86 int is_aligned_hugepage_range(unsigned long addr, unsigned long len)
  87 {
  88         if (len & ~HPAGE_MASK)
  89                 return -EINVAL;
  90         if (addr & ~HPAGE_MASK)
  91                 return -EINVAL;
  92         return 0;
  93 }
  94
  95 int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
  96                             struct vm_area_struct *vma)
  97 {
  98         pte_t *src_pte, *dst_pte, entry;
  99         struct page *ptepage;
 100         unsigned long addr = vma->vm_start;
 101         unsigned long end = vma->vm_end;
 102         int i;
 103
 104         while (addr < end) {
 105                 dst_pte = huge_pte_alloc(dst, addr);
 106                 if (!dst_pte)
 107                         goto nomem;
 108                 src_pte = huge_pte_offset(src, addr);
 109                 BUG_ON(!src_pte || pte_none(*src_pte));
 110                 entry = *src_pte;
 111                 ptepage = pte_page(entry);
 112                 get_page(ptepage);
 113                 for (i = 0; i < (1 << HUGETLB_PAGE_ORDER); i++) {
 114                         set_pte(dst_pte, entry);
 115                         pte_val(entry) += PAGE_SIZE;
 116                         dst_pte++;
 117                 }
 118                 dst->rss += (HPAGE_SIZE / PAGE_SIZE);
 119                 addr += HPAGE_SIZE;
 120         }
 121         return 0;
 122
 123 nomem:
 124         return -ENOMEM;
 125 }
 126
 127 int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
 128                         struct page **pages, struct vm_area_struct **vmas,
 129                         unsigned long *position, int *length, int i)
 130 {
 131         unsigned long vaddr = *position;
 132         int remainder = *length;
 133
 134         WARN_ON(!is_vm_hugetlb_page(vma));
 135
 136         while (vaddr < vma->vm_end && remainder) {
 137                 if (pages) {
 138                         pte_t *pte;
 139                         struct page *page;
 140
 141                         pte = huge_pte_offset(mm, vaddr);
 142
 143                         /* hugetlb should be locked, and hence, prefaulted */
 144                         BUG_ON(!pte || pte_none(*pte));
 145
 146                         page = pte_page(*pte);
 147
 148                         WARN_ON(!PageCompound(page));
 149
 150                         get_page(page);
 151                         pages[i] = page;
 152                 }
 153
 154                 if (vmas)
 155                         vmas[i] = vma;
 156
 157                 vaddr += PAGE_SIZE;
 158                 --remainder;
 159                 ++i;
 160         }
 161
 162         *length = remainder;
 163         *position = vaddr;
 164
 165         return i;
 166 }
 167
 168 struct page *follow_huge_addr(struct mm_struct *mm,
 169                               unsigned long address, int write)
 170 {
 171         return ERR_PTR(-EINVAL);
 172 }
 173
 174 int pmd_huge(pmd_t pmd)
 175 {
 176         return 0;
 177 }
 178
 179 struct page *follow_huge_pmd(struct mm_struct *mm, unsigned long address,
 180                              pmd_t *pmd, int write)
 181 {
 182         return NULL;
 183 }
 184
 185 void unmap_hugepage_range(struct vm_area_struct *vma,
 186                           unsigned long start, unsigned long end)
 187 {
 188         struct mm_struct *mm = vma->vm_mm;
 189         unsigned long address;
 190         pte_t *pte;
 191         struct page *page;
 192         int i;
 193
 194         BUG_ON(start & (HPAGE_SIZE - 1));
 195         BUG_ON(end & (HPAGE_SIZE - 1));
 196
 197         for (address = start; address < end; address += HPAGE_SIZE) {
 198                 pte = huge_pte_offset(mm, address);
 199                 BUG_ON(!pte);
 200                 if (pte_none(*pte))
 201                         continue;
 202                 page = pte_page(*pte);
 203                 put_page(page);
 204                 for (i = 0; i < (1 << HUGETLB_PAGE_ORDER); i++) {
 205                         pte_clear(pte);
 206                         pte++;
 207                 }
 208         }
 209         mm->rss -= (end - start) >> PAGE_SHIFT;
 210         flush_tlb_range(vma, start, end);
 211 }
 212
 213 int hugetlb_prefault(struct address_space *mapping, struct vm_area_struct *vma)
 214 {
 215         struct mm_struct *mm = current->mm;
 216         unsigned long addr;
 217         int ret = 0;
 218
 219         BUG_ON(vma->vm_start & ~HPAGE_MASK);
 220         BUG_ON(vma->vm_end & ~HPAGE_MASK);
 221
 222         spin_lock(&mm->page_table_lock);
 223         for (addr = vma->vm_start; addr < vma->vm_end; addr += HPAGE_SIZE) {
 224                 unsigned long idx;
 225                 pte_t *pte = huge_pte_alloc(mm, addr);
 226                 struct page *page;
 227
 228                 if (!pte) {
 229                         ret = -ENOMEM;
 230                         goto out;
 231                 }
 232                 if (!pte_none(*pte))
 233                         continue;
 234
 235                 idx = ((addr - vma->vm_start) >> HPAGE_SHIFT)
 236                         + (vma->vm_pgoff >> (HPAGE_SHIFT - PAGE_SHIFT));
 237                 page = find_get_page(mapping, idx);
 238                 if (!page) {
 239                         /* charge the fs quota first */
 240                         if (hugetlb_get_quota(mapping)) {
 241                                 ret = -ENOMEM;
 242                                 goto out;
 243                         }
 244                         page = alloc_huge_page();
 245                         if (!page) {
 246                                 hugetlb_put_quota(mapping);
 247                                 ret = -ENOMEM;
 248                                 goto out;
 249                         }
 250                         ret = add_to_page_cache(page, mapping, idx, GFP_ATOMIC);
 251                         if (! ret) {
 252                                 unlock_page(page);
 253                         } else {
 254                                 hugetlb_put_quota(mapping);
 255                                 free_huge_page(page);
 256                                 goto out;
 257                         }
 258                 }
 259                 set_huge_pte(mm, vma, page, pte, vma->vm_flags & VM_WRITE);
 260         }
 261 out:
 262         spin_unlock(&mm->page_table_lock);
 263         return ret;
 264 }