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   1 /*
   2  * arch/sh64/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 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 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         add_mm_counter(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 pte_t huge_ptep_get_and_clear(pte_t *ptep)
  84 {
  85         pte_t entry;
  86
  87         entry = *ptep;
  88
  89         for (i = 0; i < (1 << HUGETLB_PAGE_ORDER); i++) {
  90                 pte_clear(pte);
  91                 pte++;
  92         }
  93
  94         return entry;
  95 }
  96
  97 /*
  98  * This function checks for proper alignment of input addr and len parameters.
  99  */
 100 int is_aligned_hugepage_range(unsigned long addr, unsigned long len)
 101 {
 102         if (len & ~HPAGE_MASK)
 103                 return -EINVAL;
 104         if (addr & ~HPAGE_MASK)
 105                 return -EINVAL;
 106         return 0;
 107 }
 108
 109 int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
 110                             struct vm_area_struct *vma)
 111 {
 112         pte_t *src_pte, *dst_pte, entry;
 113         struct page *ptepage;
 114         unsigned long addr = vma->vm_start;
 115         unsigned long end = vma->vm_end;
 116         int i;
 117
 118         while (addr < end) {
 119                 dst_pte = huge_pte_alloc(dst, addr);
 120                 if (!dst_pte)
 121                         goto nomem;
 122                 src_pte = huge_pte_offset(src, addr);
 123                 BUG_ON(!src_pte || pte_none(*src_pte));
 124                 entry = *src_pte;
 125                 ptepage = pte_page(entry);
 126                 get_page(ptepage);
 127                 for (i = 0; i < (1 << HUGETLB_PAGE_ORDER); i++) {
 128                         set_pte(dst_pte, entry);
 129                         pte_val(entry) += PAGE_SIZE;
 130                         dst_pte++;
 131                 }
 132                 add_mm_counter(dst, rss, HPAGE_SIZE / PAGE_SIZE);
 133                 addr += HPAGE_SIZE;
 134         }
 135         return 0;
 136
 137 nomem:
 138         return -ENOMEM;
 139 }
 140
 141 int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
 142                         struct page **pages, struct vm_area_struct **vmas,
 143                         unsigned long *position, int *length, int i)
 144 {
 145         unsigned long vaddr = *position;
 146         int remainder = *length;
 147
 148         WARN_ON(!is_vm_hugetlb_page(vma));
 149
 150         while (vaddr < vma->vm_end && remainder) {
 151                 if (pages) {
 152                         pte_t *pte;
 153                         struct page *page;
 154
 155                         pte = huge_pte_offset(mm, vaddr);
 156
 157                         /* hugetlb should be locked, and hence, prefaulted */
 158                         BUG_ON(!pte || pte_none(*pte));
 159
 160                         page = pte_page(*pte);
 161
 162                         WARN_ON(!PageCompound(page));
 163
 164                         get_page(page);
 165                         pages[i] = page;
 166                 }
 167
 168                 if (vmas)
 169                         vmas[i] = vma;
 170
 171                 vaddr += PAGE_SIZE;
 172                 --remainder;
 173                 ++i;
 174         }
 175
 176         *length = remainder;
 177         *position = vaddr;
 178
 179         return i;
 180 }
 181
 182 struct page *follow_huge_addr(struct mm_struct *mm,
 183                               unsigned long address, int write)
 184 {
 185         return ERR_PTR(-EINVAL);
 186 }
 187
 188 int pmd_huge(pmd_t pmd)
 189 {
 190         return 0;
 191 }
 192
 193 struct page *follow_huge_pmd(struct mm_struct *mm, unsigned long address,
 194                              pmd_t *pmd, int write)
 195 {
 196         return NULL;
 197 }
 198
 199 void unmap_hugepage_range(struct vm_area_struct *vma,
 200                           unsigned long start, unsigned long end)
 201 {
 202         struct mm_struct *mm = vma->vm_mm;
 203         unsigned long address;
 204         pte_t *pte;
 205         struct page *page;
 206         int i;
 207
 208         BUG_ON(start & (HPAGE_SIZE - 1));
 209         BUG_ON(end & (HPAGE_SIZE - 1));
 210
 211         for (address = start; address < end; address += HPAGE_SIZE) {
 212                 pte = huge_pte_offset(mm, address);
 213                 BUG_ON(!pte);
 214                 if (pte_none(*pte))
 215                         continue;
 216                 page = pte_page(*pte);
 217                 put_page(page);
 218                 for (i = 0; i < (1 << HUGETLB_PAGE_ORDER); i++) {
 219                         pte_clear(mm, address+(i*PAGE_SIZE), pte);
 220                         pte++;
 221                 }
 222         }
 223         add_mm_counter(mm, rss, -((end - start) >> PAGE_SHIFT));
 224         flush_tlb_range(vma, start, end);
 225 }
 226
 227 int hugetlb_prefault(struct address_space *mapping, struct vm_area_struct *vma)
 228 {
 229         struct mm_struct *mm = current->mm;
 230         unsigned long addr;
 231         int ret = 0;
 232
 233         BUG_ON(vma->vm_start & ~HPAGE_MASK);
 234         BUG_ON(vma->vm_end & ~HPAGE_MASK);
 235
 236         spin_lock(&mm->page_table_lock);
 237         for (addr = vma->vm_start; addr < vma->vm_end; addr += HPAGE_SIZE) {
 238                 unsigned long idx;
 239                 pte_t *pte = huge_pte_alloc(mm, addr);
 240                 struct page *page;
 241
 242                 if (!pte) {
 243                         ret = -ENOMEM;
 244                         goto out;
 245                 }
 246                 if (!pte_none(*pte))
 247                         continue;
 248
 249                 idx = ((addr - vma->vm_start) >> HPAGE_SHIFT)
 250                         + (vma->vm_pgoff >> (HPAGE_SHIFT - PAGE_SHIFT));
 251                 page = find_get_page(mapping, idx);
 252                 if (!page) {
 253                         /* charge the fs quota first */
 254                         if (hugetlb_get_quota(mapping)) {
 255                                 ret = -ENOMEM;
 256                                 goto out;
 257                         }
 258                         page = alloc_huge_page();
 259                         if (!page) {
 260                                 hugetlb_put_quota(mapping);
 261                                 ret = -ENOMEM;
 262                                 goto out;
 263                         }
 264                         ret = add_to_page_cache(page, mapping, idx, GFP_ATOMIC);
 265                         if (! ret) {
 266                                 unlock_page(page);
 267                         } else {
 268                                 hugetlb_put_quota(mapping);
 269                                 free_huge_page(page);
 270                                 goto out;
 271                         }
 272                 }
 273                 set_huge_pte(mm, vma, page, pte, vma->vm_flags & VM_WRITE);
 274         }
 275 out:
 276         spin_unlock(&mm->page_table_lock);
 277         return ret;
 278 }