arch/i386/mm/hugetlbpage.c

   1 /*
   2  * IA-32 Huge TLB Page Support for Kernel.
   3  *
   4  * Copyright (C) 2002, Rohit Seth <rohit.seth@intel.com>
   5  */
   6
   7 #include <linux/config.h>
   8 #include <linux/init.h>
   9 #include <linux/fs.h>
  10 #include <linux/mm.h>
  11 #include <linux/hugetlb.h>
  12 #include <linux/pagemap.h>
  13 #include <linux/smp_lock.h>
  14 #include <linux/slab.h>
  15 #include <linux/err.h>
  16 #include <linux/sysctl.h>
  17 #include <asm/mman.h>
  18 #include <asm/tlb.h>
  19 #include <asm/tlbflush.h>
  20
  21 static pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr)
  22 {
  23         pgd_t *pgd;
  24         pmd_t *pmd = NULL;
  25
  26         pgd = pgd_offset(mm, addr);
  27         pmd = pmd_alloc(mm, pgd, addr);
  28         return (pte_t *) pmd;
  29 }
  30
  31 static pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
  32 {
  33         pgd_t *pgd;
  34         pmd_t *pmd = NULL;
  35
  36         pgd = pgd_offset(mm, addr);
  37         pmd = pmd_offset(pgd, addr);
  38         return (pte_t *) pmd;
  39 }
  40
  41 static void set_huge_pte(struct mm_struct *mm, struct vm_area_struct *vma, struct page *page, pte_t * page_table, int write_access)
  42 {
  43         pte_t entry;
  44
  45         // mm->rss += (HPAGE_SIZE / PAGE_SIZE);
  46         vx_rsspages_add(mm, HPAGE_SIZE / PAGE_SIZE);
  47         if (write_access) {
  48                 entry =
  49                     pte_mkwrite(pte_mkdirty(mk_pte(page, vma->vm_page_prot)));
  50         } else
  51                 entry = pte_wrprotect(mk_pte(page, vma->vm_page_prot));
  52         entry = pte_mkyoung(entry);
  53         mk_pte_huge(entry);
  54         set_pte(page_table, entry);
  55 }
  56
  57 /*
  58  * This function checks for proper alignment of input addr and len parameters.
  59  */
  60 int is_aligned_hugepage_range(unsigned long addr, unsigned long len)
  61 {
  62         if (len & ~HPAGE_MASK)
  63                 return -EINVAL;
  64         if (addr & ~HPAGE_MASK)
  65                 return -EINVAL;
  66         return 0;
  67 }
  68
  69 int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
  70                         struct vm_area_struct *vma)
  71 {
  72         pte_t *src_pte, *dst_pte, entry;
  73         struct page *ptepage;
  74         unsigned long addr = vma->vm_start;
  75         unsigned long end = vma->vm_end;
  76
  77         while (addr < end) {
  78                 dst_pte = huge_pte_alloc(dst, addr);
  79                 if (!dst_pte)
  80                         goto nomem;
  81                 src_pte = huge_pte_offset(src, addr);
  82                 entry = *src_pte;
  83                 ptepage = pte_page(entry);
  84                 get_page(ptepage);
  85                 set_pte(dst_pte, entry);
  86                 // dst->rss += (HPAGE_SIZE / PAGE_SIZE);
  87                 vx_rsspages_add(dst, HPAGE_SIZE / PAGE_SIZE);
  88                 addr += HPAGE_SIZE;
  89         }
  90         return 0;
  91
  92 nomem:
  93         return -ENOMEM;
  94 }
  95
  96 int
  97 follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
  98                     struct page **pages, struct vm_area_struct **vmas,
  99                     unsigned long *position, int *length, int i)
 100 {
 101         unsigned long vpfn, vaddr = *position;
 102         int remainder = *length;
 103
 104         WARN_ON(!is_vm_hugetlb_page(vma));
 105
 106         vpfn = vaddr/PAGE_SIZE;
 107         while (vaddr < vma->vm_end && remainder) {
 108
 109                 if (pages) {
 110                         pte_t *pte;
 111                         struct page *page;
 112
 113                         pte = huge_pte_offset(mm, vaddr);
 114
 115                         /* hugetlb should be locked, and hence, prefaulted */
 116                         WARN_ON(!pte || pte_none(*pte));
 117
 118                         page = &pte_page(*pte)[vpfn % (HPAGE_SIZE/PAGE_SIZE)];
 119
 120                         WARN_ON(!PageCompound(page));
 121
 122                         get_page(page);
 123                         pages[i] = page;
 124                 }
 125
 126                 if (vmas)
 127                         vmas[i] = vma;
 128
 129                 vaddr += PAGE_SIZE;
 130                 ++vpfn;
 131                 --remainder;
 132                 ++i;
 133         }
 134
 135         *length = remainder;
 136         *position = vaddr;
 137
 138         return i;
 139 }
 140
 141 #if 0   /* This is just for testing */
 142 struct page *
 143 follow_huge_addr(struct mm_struct *mm, unsigned long address, int write)
 144 {
 145         unsigned long start = address;
 146         int length = 1;
 147         int nr;
 148         struct page *page;
 149         struct vm_area_struct *vma;
 150
 151         vma = find_vma(mm, addr);
 152         if (!vma || !is_vm_hugetlb_page(vma))
 153                 return ERR_PTR(-EINVAL);
 154
 155         pte = huge_pte_offset(mm, address);
 156
 157         /* hugetlb should be locked, and hence, prefaulted */
 158         WARN_ON(!pte || pte_none(*pte));
 159
 160         page = &pte_page(*pte)[vpfn % (HPAGE_SIZE/PAGE_SIZE)];
 161
 162         WARN_ON(!PageCompound(page));
 163
 164         return page;
 165 }
 166
 167 int pmd_huge(pmd_t pmd)
 168 {
 169         return 0;
 170 }
 171
 172 struct page *
 173 follow_huge_pmd(struct mm_struct *mm, unsigned long address,
 174                 pmd_t *pmd, int write)
 175 {
 176         return NULL;
 177 }
 178
 179 #else
 180
 181 struct page *
 182 follow_huge_addr(struct mm_struct *mm, unsigned long address, int write)
 183 {
 184         return ERR_PTR(-EINVAL);
 185 }
 186
 187 int pmd_huge(pmd_t pmd)
 188 {
 189         return !!(pmd_val(pmd) & _PAGE_PSE);
 190 }
 191
 192 struct page *
 193 follow_huge_pmd(struct mm_struct *mm, unsigned long address,
 194                 pmd_t *pmd, int write)
 195 {
 196         struct page *page;
 197
 198         page = pte_page(*(pte_t *)pmd);
 199         if (page)
 200                 page += ((address & ~HPAGE_MASK) >> PAGE_SHIFT);
 201         return page;
 202 }
 203 #endif
 204
 205 void unmap_hugepage_range(struct vm_area_struct *vma,
 206                 unsigned long start, unsigned long end)
 207 {
 208         struct mm_struct *mm = vma->vm_mm;
 209         unsigned long address;
 210         pte_t pte;
 211         struct page *page;
 212
 213         BUG_ON(start & (HPAGE_SIZE - 1));
 214         BUG_ON(end & (HPAGE_SIZE - 1));
 215
 216         for (address = start; address < end; address += HPAGE_SIZE) {
 217                 pte = ptep_get_and_clear(huge_pte_offset(mm, address));
 218                 if (pte_none(pte))
 219                         continue;
 220                 page = pte_page(pte);
 221                 put_page(page);
 222         }
 223         // mm->rss -= (end - start) >> PAGE_SHIFT;
 224         vx_rsspages_sub(mm, (end - start) >> PAGE_SHIFT);
 225         flush_tlb_range(vma, start, end);
 226 }
 227
 228 int hugetlb_prefault(struct address_space *mapping, struct vm_area_struct *vma)
 229 {
 230         struct mm_struct *mm = current->mm;
 231         unsigned long addr;
 232         int ret = 0;
 233
 234         BUG_ON(vma->vm_start & ~HPAGE_MASK);
 235         BUG_ON(vma->vm_end & ~HPAGE_MASK);
 236
 237         spin_lock(&mm->page_table_lock);
 238         for (addr = vma->vm_start; addr < vma->vm_end; addr += HPAGE_SIZE) {
 239                 unsigned long idx;
 240                 pte_t *pte = huge_pte_alloc(mm, addr);
 241                 struct page *page;
 242
 243                 if (!pte) {
 244                         ret = -ENOMEM;
 245                         goto out;
 246                 }
 247
 248                 if (!pte_none(*pte)) {
 249                         pmd_t *pmd = (pmd_t *) pte;
 250
 251                         page = pmd_page(*pmd);
 252                         pmd_clear(pmd);
 253                         dec_page_state(nr_page_table_pages);
 254                         page_cache_release(page);
 255                 }
 256
 257                 idx = ((addr - vma->vm_start) >> HPAGE_SHIFT)
 258                         + (vma->vm_pgoff >> (HPAGE_SHIFT - PAGE_SHIFT));
 259                 page = find_get_page(mapping, idx);
 260                 if (!page) {
 261                         /* charge the fs quota first */
 262                         if (hugetlb_get_quota(mapping)) {
 263                                 ret = -ENOMEM;
 264                                 goto out;
 265                         }
 266                         page = alloc_huge_page();
 267                         if (!page) {
 268                                 hugetlb_put_quota(mapping);
 269                                 ret = -ENOMEM;
 270                                 goto out;
 271                         }
 272                         ret = add_to_page_cache(page, mapping, idx, GFP_ATOMIC);
 273                         if (! ret) {
 274                                 unlock_page(page);
 275                         } else {
 276                                 hugetlb_put_quota(mapping);
 277                                 free_huge_page(page);
 278                                 goto out;
 279                         }
 280                 }
 281                 set_huge_pte(mm, vma, page, pte, vma->vm_flags & VM_WRITE);
 282         }
 283 out:
 284         spin_unlock(&mm->page_table_lock);
 285         return ret;
 286 }