arch/sparc/mm/hugetlbpage.c

   1 /*
   2  * SPARC64 Huge TLB page support.
   3  *
   4  * Copyright (C) 2002, 2003, 2006 David S. Miller (davem@davemloft.net)
   5  */
   6
   7 #include <linux/fs.h>
   8 #include <linux/mm.h>
   9 #include <linux/hugetlb.h>
  10 #include <linux/pagemap.h>
  11 #include <linux/sysctl.h>
  12
  13 #include <asm/mman.h>
  14 #include <asm/pgalloc.h>
  15 #include <asm/tlb.h>
  16 #include <asm/tlbflush.h>
  17 #include <asm/cacheflush.h>
  18 #include <asm/mmu_context.h>
  19
  20 /* Slightly simplified from the non-hugepage variant because by
  21  * definition we don't have to worry about any page coloring stuff
  22  */
  23
  24 static unsigned long hugetlb_get_unmapped_area_bottomup(struct file *filp,
  25                                                         unsigned long addr,
  26                                                         unsigned long len,
  27                                                         unsigned long pgoff,
  28                                                         unsigned long flags)
  29 {
  30         unsigned long task_size = TASK_SIZE;
  31         struct vm_unmapped_area_info info;
  32
  33         if (test_thread_flag(TIF_32BIT))
  34                 task_size = STACK_TOP32;
  35
  36         info.flags = 0;
  37         info.length = len;
  38         info.low_limit = TASK_UNMAPPED_BASE;
  39         info.high_limit = min(task_size, VA_EXCLUDE_START);
  40         info.align_mask = PAGE_MASK & ~HPAGE_MASK;
  41         info.align_offset = 0;
  42         addr = vm_unmapped_area(&info);
  43
  44         if ((addr & ~PAGE_MASK) && task_size > VA_EXCLUDE_END) {
  45                 VM_BUG_ON(addr != -ENOMEM);
  46                 info.low_limit = VA_EXCLUDE_END;
  47                 info.high_limit = task_size;
  48                 addr = vm_unmapped_area(&info);
  49         }
  50
  51         return addr;
  52 }
  53
  54 static unsigned long
  55 hugetlb_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
  56                                   const unsigned long len,
  57                                   const unsigned long pgoff,
  58                                   const unsigned long flags)
  59 {
  60         struct mm_struct *mm = current->mm;
  61         unsigned long addr = addr0;
  62         struct vm_unmapped_area_info info;
  63
  64         /* This should only ever run for 32-bit processes.  */
  65         BUG_ON(!test_thread_flag(TIF_32BIT));
  66
  67         info.flags = VM_UNMAPPED_AREA_TOPDOWN;
  68         info.length = len;
  69         info.low_limit = PAGE_SIZE;
  70         info.high_limit = mm->mmap_base;
  71         info.align_mask = PAGE_MASK & ~HPAGE_MASK;
  72         info.align_offset = 0;
  73         addr = vm_unmapped_area(&info);
  74
  75         /*
  76          * A failed mmap() very likely causes application failure,
  77          * so fall back to the bottom-up function here. This scenario
  78          * can happen with large stack limits and large mmap()
  79          * allocations.
  80          */
  81         if (addr & ~PAGE_MASK) {
  82                 VM_BUG_ON(addr != -ENOMEM);
  83                 info.flags = 0;
  84                 info.low_limit = TASK_UNMAPPED_BASE;
  85                 info.high_limit = STACK_TOP32;
  86                 addr = vm_unmapped_area(&info);
  87         }
  88
  89         return addr;
  90 }
  91
  92 unsigned long
  93 hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
  94                 unsigned long len, unsigned long pgoff, unsigned long flags)
  95 {
  96         struct mm_struct *mm = current->mm;
  97         struct vm_area_struct *vma;
  98         unsigned long task_size = TASK_SIZE;
  99
 100         if (test_thread_flag(TIF_32BIT))
 101                 task_size = STACK_TOP32;
 102
 103         if (len & ~HPAGE_MASK)
 104                 return -EINVAL;
 105         if (len > task_size)
 106                 return -ENOMEM;
 107
 108         if (flags & MAP_FIXED) {
 109                 if (prepare_hugepage_range(file, addr, len))
 110                         return -EINVAL;
 111                 return addr;
 112         }
 113
 114         if (addr) {
 115                 addr = ALIGN(addr, HPAGE_SIZE);
 116                 vma = find_vma(mm, addr);
 117                 if (task_size - len >= addr &&
 118                     (!vma || addr + len <= vma->vm_start))
 119                         return addr;
 120         }
 121         if (mm->get_unmapped_area == arch_get_unmapped_area)
 122                 return hugetlb_get_unmapped_area_bottomup(file, addr, len,
 123                                 pgoff, flags);
 124         else
 125                 return hugetlb_get_unmapped_area_topdown(file, addr, len,
 126                                 pgoff, flags);
 127 }
 128
 129 pte_t *huge_pte_alloc(struct mm_struct *mm,
 130                         unsigned long addr, unsigned long sz)
 131 {
 132         pgd_t *pgd;
 133         pud_t *pud;
 134         pmd_t *pmd;
 135         pte_t *pte = NULL;
 136
 137         /* We must align the address, because our caller will run
 138          * set_huge_pte_at() on whatever we return, which writes out
 139          * all of the sub-ptes for the hugepage range.  So we have
 140          * to give it the first such sub-pte.
 141          */
 142         addr &= HPAGE_MASK;
 143
 144         pgd = pgd_offset(mm, addr);
 145         pud = pud_alloc(mm, pgd, addr);
 146         if (pud) {
 147                 pmd = pmd_alloc(mm, pud, addr);
 148                 if (pmd)
 149                         pte = pte_alloc_map(mm, NULL, pmd, addr);
 150         }
 151         return pte;
 152 }
 153
 154 pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
 155 {
 156         pgd_t *pgd;
 157         pud_t *pud;
 158         pmd_t *pmd;
 159         pte_t *pte = NULL;
 160
 161         addr &= HPAGE_MASK;
 162
 163         pgd = pgd_offset(mm, addr);
 164         if (!pgd_none(*pgd)) {
 165                 pud = pud_offset(pgd, addr);
 166                 if (!pud_none(*pud)) {
 167                         pmd = pmd_offset(pud, addr);
 168                         if (!pmd_none(*pmd))
 169                                 pte = pte_offset_map(pmd, addr);
 170                 }
 171         }
 172         return pte;
 173 }
 174
 175 int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
 176 {
 177         return 0;
 178 }
 179
 180 void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
 181                      pte_t *ptep, pte_t entry)
 182 {
 183         int i;
 184
 185         if (!pte_present(*ptep) && pte_present(entry))
 186                 mm->context.huge_pte_count++;
 187
 188         addr &= HPAGE_MASK;
 189         for (i = 0; i < (1 << HUGETLB_PAGE_ORDER); i++) {
 190                 set_pte_at(mm, addr, ptep, entry);
 191                 ptep++;
 192                 addr += PAGE_SIZE;
 193                 pte_val(entry) += PAGE_SIZE;
 194         }
 195 }
 196
 197 pte_t huge_ptep_get_and_clear(struct mm_struct *mm, unsigned long addr,
 198                               pte_t *ptep)
 199 {
 200         pte_t entry;
 201         int i;
 202
 203         entry = *ptep;
 204         if (pte_present(entry))
 205                 mm->context.huge_pte_count--;
 206
 207         addr &= HPAGE_MASK;
 208
 209         for (i = 0; i < (1 << HUGETLB_PAGE_ORDER); i++) {
 210                 pte_clear(mm, addr, ptep);
 211                 addr += PAGE_SIZE;
 212                 ptep++;
 213         }
 214
 215         return entry;
 216 }
 217
 218 struct page *follow_huge_addr(struct mm_struct *mm,
 219                               unsigned long address, int write)
 220 {
 221         return ERR_PTR(-EINVAL);
 222 }
 223
 224 int pmd_huge(pmd_t pmd)
 225 {
 226         return 0;
 227 }
 228
 229 int pud_huge(pud_t pud)
 230 {
 231         return 0;
 232 }
 233
 234 int pmd_huge_support(void)
 235 {
 236         return 0;
 237 }
 238
 239 struct page *follow_huge_pmd(struct mm_struct *mm, unsigned long address,
 240                              pmd_t *pmd, int write)
 241 {
 242         return NULL;
 243 }