arch/x86/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/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/err.h>
  13 #include <linux/sysctl.h>
  14 #include <asm/mman.h>
  15 #include <asm/tlb.h>
  16 #include <asm/tlbflush.h>
  17 #include <asm/pgalloc.h>
  18
  19 #if 0   /* This is just for testing */
  20 struct page *
  21 follow_huge_addr(struct mm_struct *mm, unsigned long address, int write)
  22 {
  23         unsigned long start = address;
  24         int length = 1;
  25         int nr;
  26         struct page *page;
  27         struct vm_area_struct *vma;
  28
  29         vma = find_vma(mm, addr);
  30         if (!vma || !is_vm_hugetlb_page(vma))
  31                 return ERR_PTR(-EINVAL);
  32
  33         pte = huge_pte_offset(mm, address);
  34
  35         /* hugetlb should be locked, and hence, prefaulted */
  36         WARN_ON(!pte || pte_none(*pte));
  37
  38         page = &pte_page(*pte)[vpfn % (HPAGE_SIZE/PAGE_SIZE)];
  39
  40         WARN_ON(!PageHead(page));
  41
  42         return page;
  43 }
  44
  45 int pmd_huge(pmd_t pmd)
  46 {
  47         return 0;
  48 }
  49
  50 int pud_huge(pud_t pud)
  51 {
  52         return 0;
  53 }
  54
  55 struct page *
  56 follow_huge_pmd(struct mm_struct *mm, unsigned long address,
  57                 pmd_t *pmd, int write)
  58 {
  59         return NULL;
  60 }
  61
  62 int pmd_huge_support(void)
  63 {
  64         return 0;
  65 }
  66 #else
  67
  68 struct page *
  69 follow_huge_addr(struct mm_struct *mm, unsigned long address, int write)
  70 {
  71         return ERR_PTR(-EINVAL);
  72 }
  73
  74 int pmd_huge(pmd_t pmd)
  75 {
  76         return !!(pmd_val(pmd) & _PAGE_PSE);
  77 }
  78
  79 int pud_huge(pud_t pud)
  80 {
  81         return !!(pud_val(pud) & _PAGE_PSE);
  82 }
  83
  84 int pmd_huge_support(void)
  85 {
  86         return 1;
  87 }
  88 #endif
  89
  90 #ifdef CONFIG_HUGETLB_PAGE
  91 static unsigned long hugetlb_get_unmapped_area_bottomup(struct file *file,
  92                 unsigned long addr, unsigned long len,
  93                 unsigned long pgoff, unsigned long flags)
  94 {
  95         struct hstate *h = hstate_file(file);
  96         struct vm_unmapped_area_info info;
  97
  98         info.flags = 0;
  99         info.length = len;
 100         info.low_limit = current->mm->mmap_legacy_base;
 101         info.high_limit = TASK_SIZE;
 102         info.align_mask = PAGE_MASK & ~huge_page_mask(h);
 103         info.align_offset = 0;
 104         return vm_unmapped_area(&info);
 105 }
 106
 107 static unsigned long hugetlb_get_unmapped_area_topdown(struct file *file,
 108                 unsigned long addr0, unsigned long len,
 109                 unsigned long pgoff, unsigned long flags)
 110 {
 111         struct hstate *h = hstate_file(file);
 112         struct vm_unmapped_area_info info;
 113         unsigned long addr;
 114
 115         info.flags = VM_UNMAPPED_AREA_TOPDOWN;
 116         info.length = len;
 117         info.low_limit = PAGE_SIZE;
 118         info.high_limit = current->mm->mmap_base;
 119         info.align_mask = PAGE_MASK & ~huge_page_mask(h);
 120         info.align_offset = 0;
 121         addr = vm_unmapped_area(&info);
 122
 123         /*
 124          * A failed mmap() very likely causes application failure,
 125          * so fall back to the bottom-up function here. This scenario
 126          * can happen with large stack limits and large mmap()
 127          * allocations.
 128          */
 129         if (addr & ~PAGE_MASK) {
 130                 VM_BUG_ON(addr != -ENOMEM);
 131                 info.flags = 0;
 132                 info.low_limit = TASK_UNMAPPED_BASE;
 133                 info.high_limit = TASK_SIZE;
 134                 addr = vm_unmapped_area(&info);
 135         }
 136
 137         return addr;
 138 }
 139
 140 unsigned long
 141 hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
 142                 unsigned long len, unsigned long pgoff, unsigned long flags)
 143 {
 144         struct hstate *h = hstate_file(file);
 145         struct mm_struct *mm = current->mm;
 146         struct vm_area_struct *vma;
 147
 148         if (len & ~huge_page_mask(h))
 149                 return -EINVAL;
 150         if (len > TASK_SIZE)
 151                 return -ENOMEM;
 152
 153         if (flags & MAP_FIXED) {
 154                 if (prepare_hugepage_range(file, addr, len))
 155                         return -EINVAL;
 156                 return addr;
 157         }
 158
 159         if (addr) {
 160                 addr = ALIGN(addr, huge_page_size(h));
 161                 vma = find_vma(mm, addr);
 162                 if (TASK_SIZE - len >= addr &&
 163                     (!vma || addr + len <= vma->vm_start))
 164                         return addr;
 165         }
 166         if (mm->get_unmapped_area == arch_get_unmapped_area)
 167                 return hugetlb_get_unmapped_area_bottomup(file, addr, len,
 168                                 pgoff, flags);
 169         else
 170                 return hugetlb_get_unmapped_area_topdown(file, addr, len,
 171                                 pgoff, flags);
 172 }
 173 #endif /* CONFIG_HUGETLB_PAGE */
 174
 175 #ifdef CONFIG_X86_64
 176 static __init int setup_hugepagesz(char *opt)
 177 {
 178         unsigned long ps = memparse(opt, &opt);
 179         if (ps == PMD_SIZE) {
 180                 hugetlb_add_hstate(PMD_SHIFT - PAGE_SHIFT);
 181         } else if (ps == PUD_SIZE && cpu_has_gbpages) {
 182                 hugetlb_add_hstate(PUD_SHIFT - PAGE_SHIFT);
 183         } else {
 184                 printk(KERN_ERR "hugepagesz: Unsupported page size %lu M\n",
 185                         ps >> 20);
 186                 return 0;
 187         }
 188         return 1;
 189 }
 190 __setup("hugepagesz=", setup_hugepagesz);
 191 #endif