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/init.h>
   8 #include <linux/fs.h>
   9 #include <linux/mm.h>
  10 #include <linux/hugetlb.h>
  11 #include <linux/pagemap.h>
  12 #include <linux/sysctl.h>
  13
  14 #include <asm/mman.h>
  15 #include <asm/pgalloc.h>
  16 #include <asm/tlb.h>
  17 #include <asm/tlbflush.h>
  18 #include <asm/cacheflush.h>
  19 #include <asm/mmu_context.h>
  20
  21 /* Slightly simplified from the non-hugepage variant because by
  22  * definition we don't have to worry about any page coloring stuff
  23  */
  24 #define VA_EXCLUDE_START (0x0000080000000000UL - (1UL << 32UL))
  25 #define VA_EXCLUDE_END   (0xfffff80000000000UL + (1UL << 32UL))
  26
  27 static unsigned long hugetlb_get_unmapped_area_bottomup(struct file *filp,
  28                                                         unsigned long addr,
  29                                                         unsigned long len,
  30                                                         unsigned long pgoff,
  31                                                         unsigned long flags)
  32 {
  33         unsigned long task_size = TASK_SIZE;
  34         struct vm_unmapped_area_info info;
  35
  36         if (test_thread_flag(TIF_32BIT))
  37                 task_size = STACK_TOP32;
  38
  39         info.flags = 0;
  40         info.length = len;
  41         info.low_limit = TASK_UNMAPPED_BASE;
  42         info.high_limit = min(task_size, VA_EXCLUDE_START);
  43         info.align_mask = PAGE_MASK & ~HPAGE_MASK;
  44         info.align_offset = 0;
  45         addr = vm_unmapped_area(&info);
  46
  47         if ((addr & ~PAGE_MASK) && task_size > VA_EXCLUDE_END) {
  48                 VM_BUG_ON(addr != -ENOMEM);
  49                 info.low_limit = VA_EXCLUDE_END;
  50                 info.high_limit = task_size;
  51                 addr = vm_unmapped_area(&info);
  52         }
  53
  54         return addr;
  55 }
  56
  57 static unsigned long
  58 hugetlb_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
  59                                   const unsigned long len,
  60                                   const unsigned long pgoff,
  61                                   const unsigned long flags)
  62 {
  63         struct mm_struct *mm = current->mm;
  64         unsigned long addr = addr0;
  65         struct vm_unmapped_area_info info;
  66
  67         /* This should only ever run for 32-bit processes.  */
  68         BUG_ON(!test_thread_flag(TIF_32BIT));
  69
  70         info.flags = VM_UNMAPPED_AREA_TOPDOWN;
  71         info.length = len;
  72         info.low_limit = PAGE_SIZE;
  73         info.high_limit = mm->mmap_base;
  74         info.align_mask = PAGE_MASK & ~HPAGE_MASK;
  75         info.align_offset = 0;
  76         addr = vm_unmapped_area(&info);
  77
  78         /*
  79          * A failed mmap() very likely causes application failure,
  80          * so fall back to the bottom-up function here. This scenario
  81          * can happen with large stack limits and large mmap()
  82          * allocations.
  83          */
  84         if (addr & ~PAGE_MASK) {
  85                 VM_BUG_ON(addr != -ENOMEM);
  86                 info.flags = 0;
  87                 info.low_limit = TASK_UNMAPPED_BASE;
  88                 info.high_limit = STACK_TOP32;
  89                 addr = vm_unmapped_area(&info);
  90         }
  91
  92         return addr;
  93 }
  94
  95 unsigned long
  96 hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
  97                 unsigned long len, unsigned long pgoff, unsigned long flags)
  98 {
  99         struct mm_struct *mm = current->mm;
 100         struct vm_area_struct *vma;
 101         unsigned long task_size = TASK_SIZE;
 102
 103         if (test_thread_flag(TIF_32BIT))
 104                 task_size = STACK_TOP32;
 105
 106         if (len & ~HPAGE_MASK)
 107                 return -EINVAL;
 108         if (len > task_size)
 109                 return -ENOMEM;
 110
 111         if (flags & MAP_FIXED) {
 112                 if (prepare_hugepage_range(file, addr, len))
 113                         return -EINVAL;
 114                 return addr;
 115         }
 116
 117         if (addr) {
 118                 addr = ALIGN(addr, HPAGE_SIZE);
 119                 vma = find_vma(mm, addr);
 120                 if (task_size - len >= addr &&
 121                     (!vma || addr + len <= vma->vm_start))
 122                         return addr;
 123         }
 124         if (mm->get_unmapped_area == arch_get_unmapped_area)
 125                 return hugetlb_get_unmapped_area_bottomup(file, addr, len,
 126                                 pgoff, flags);
 127         else
 128                 return hugetlb_get_unmapped_area_topdown(file, addr, len,
 129                                 pgoff, flags);
 130 }
 131
 132 pte_t *huge_pte_alloc(struct mm_struct *mm,
 133                         unsigned long addr, unsigned long sz)
 134 {
 135         pgd_t *pgd;
 136         pud_t *pud;
 137         pmd_t *pmd;
 138         pte_t *pte = NULL;
 139
 140         /* We must align the address, because our caller will run
 141          * set_huge_pte_at() on whatever we return, which writes out
 142          * all of the sub-ptes for the hugepage range.  So we have
 143          * to give it the first such sub-pte.
 144          */
 145         addr &= HPAGE_MASK;
 146
 147         pgd = pgd_offset(mm, addr);
 148         pud = pud_alloc(mm, pgd, addr);
 149         if (pud) {
 150                 pmd = pmd_alloc(mm, pud, addr);
 151                 if (pmd)
 152                         pte = pte_alloc_map(mm, NULL, pmd, addr);
 153         }
 154         return pte;
 155 }
 156
 157 pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
 158 {
 159         pgd_t *pgd;
 160         pud_t *pud;
 161         pmd_t *pmd;
 162         pte_t *pte = NULL;
 163
 164         addr &= HPAGE_MASK;
 165
 166         pgd = pgd_offset(mm, addr);
 167         if (!pgd_none(*pgd)) {
 168                 pud = pud_offset(pgd, addr);
 169                 if (!pud_none(*pud)) {
 170                         pmd = pmd_offset(pud, addr);
 171                         if (!pmd_none(*pmd))
 172                                 pte = pte_offset_map(pmd, addr);
 173                 }
 174         }
 175         return pte;
 176 }
 177
 178 int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
 179 {
 180         return 0;
 181 }
 182
 183 void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
 184                      pte_t *ptep, pte_t entry)
 185 {
 186         int i;
 187
 188         if (!pte_present(*ptep) && pte_present(entry))
 189                 mm->context.huge_pte_count++;
 190
 191         addr &= HPAGE_MASK;
 192         for (i = 0; i < (1 << HUGETLB_PAGE_ORDER); i++) {
 193                 set_pte_at(mm, addr, ptep, entry);
 194                 ptep++;
 195                 addr += PAGE_SIZE;
 196                 pte_val(entry) += PAGE_SIZE;
 197         }
 198 }
 199
 200 pte_t huge_ptep_get_and_clear(struct mm_struct *mm, unsigned long addr,
 201                               pte_t *ptep)
 202 {
 203         pte_t entry;
 204         int i;
 205
 206         entry = *ptep;
 207         if (pte_present(entry))
 208                 mm->context.huge_pte_count--;
 209
 210         addr &= HPAGE_MASK;
 211
 212         for (i = 0; i < (1 << HUGETLB_PAGE_ORDER); i++) {
 213                 pte_clear(mm, addr, ptep);
 214                 addr += PAGE_SIZE;
 215                 ptep++;
 216         }
 217
 218         return entry;
 219 }
 220
 221 struct page *follow_huge_addr(struct mm_struct *mm,
 222                               unsigned long address, int write)
 223 {
 224         return ERR_PTR(-EINVAL);
 225 }
 226
 227 int pmd_huge(pmd_t pmd)
 228 {
 229         return 0;
 230 }
 231
 232 int pud_huge(pud_t pud)
 233 {
 234         return 0;
 235 }
 236
 237 int pmd_huge_support(void)
 238 {
 239         return 0;
 240 }
 241
 242 struct page *follow_huge_pmd(struct mm_struct *mm, unsigned long address,
 243                              pmd_t *pmd, int write)
 244 {
 245         return NULL;
 246 }