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 #else
  63
  64 struct page *
  65 follow_huge_addr(struct mm_struct *mm, unsigned long address, int write)
  66 {
  67         return ERR_PTR(-EINVAL);
  68 }
  69
  70 int pmd_huge(pmd_t pmd)
  71 {
  72         return !!(pmd_val(pmd) & _PAGE_PSE);
  73 }
  74
  75 int pud_huge(pud_t pud)
  76 {
  77         return !!(pud_val(pud) & _PAGE_PSE);
  78 }
  79
  80 #endif
  81
  82 /* x86_64 also uses this file */
  83
  84 #ifdef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
  85 static unsigned long hugetlb_get_unmapped_area_bottomup(struct file *file,
  86                 unsigned long addr, unsigned long len,
  87                 unsigned long pgoff, unsigned long flags)
  88 {
  89         struct hstate *h = hstate_file(file);
  90         struct vm_unmapped_area_info info;
  91
  92         info.flags = 0;
  93         info.length = len;
  94         info.low_limit = TASK_UNMAPPED_BASE;
  95         info.high_limit = TASK_SIZE;
  96         info.align_mask = PAGE_MASK & ~huge_page_mask(h);
  97         info.align_offset = 0;
  98         return vm_unmapped_area(&info);
  99 }
 100
 101 static unsigned long hugetlb_get_unmapped_area_topdown(struct file *file,
 102                 unsigned long addr0, unsigned long len,
 103                 unsigned long pgoff, unsigned long flags)
 104 {
 105         struct hstate *h = hstate_file(file);
 106         struct vm_unmapped_area_info info;
 107         unsigned long addr;
 108
 109         info.flags = VM_UNMAPPED_AREA_TOPDOWN;
 110         info.length = len;
 111         info.low_limit = PAGE_SIZE;
 112         info.high_limit = current->mm->mmap_base;
 113         info.align_mask = PAGE_MASK & ~huge_page_mask(h);
 114         info.align_offset = 0;
 115         addr = vm_unmapped_area(&info);
 116
 117         /*
 118          * A failed mmap() very likely causes application failure,
 119          * so fall back to the bottom-up function here. This scenario
 120          * can happen with large stack limits and large mmap()
 121          * allocations.
 122          */
 123         if (addr & ~PAGE_MASK) {
 124                 VM_BUG_ON(addr != -ENOMEM);
 125                 info.flags = 0;
 126                 info.low_limit = TASK_UNMAPPED_BASE;
 127                 info.high_limit = TASK_SIZE;
 128                 addr = vm_unmapped_area(&info);
 129         }
 130
 131         return addr;
 132 }
 133
 134 unsigned long
 135 hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
 136                 unsigned long len, unsigned long pgoff, unsigned long flags)
 137 {
 138         struct hstate *h = hstate_file(file);
 139         struct mm_struct *mm = current->mm;
 140         struct vm_area_struct *vma;
 141
 142         if (len & ~huge_page_mask(h))
 143                 return -EINVAL;
 144         if (len > TASK_SIZE)
 145                 return -ENOMEM;
 146
 147         if (flags & MAP_FIXED) {
 148                 if (prepare_hugepage_range(file, addr, len))
 149                         return -EINVAL;
 150                 return addr;
 151         }
 152
 153         if (addr) {
 154                 addr = ALIGN(addr, huge_page_size(h));
 155                 vma = find_vma(mm, addr);
 156                 if (TASK_SIZE - len >= addr &&
 157                     (!vma || addr + len <= vma->vm_start))
 158                         return addr;
 159         }
 160         if (mm->get_unmapped_area == arch_get_unmapped_area)
 161                 return hugetlb_get_unmapped_area_bottomup(file, addr, len,
 162                                 pgoff, flags);
 163         else
 164                 return hugetlb_get_unmapped_area_topdown(file, addr, len,
 165                                 pgoff, flags);
 166 }
 167
 168 #endif /*HAVE_ARCH_HUGETLB_UNMAPPED_AREA*/
 169
 170 #ifdef CONFIG_X86_64
 171 static __init int setup_hugepagesz(char *opt)
 172 {
 173         unsigned long ps = memparse(opt, &opt);
 174         if (ps == PMD_SIZE) {
 175                 hugetlb_add_hstate(PMD_SHIFT - PAGE_SHIFT);
 176         } else if (ps == PUD_SIZE && cpu_has_gbpages) {
 177                 hugetlb_add_hstate(PUD_SHIFT - PAGE_SHIFT);
 178         } else {
 179                 printk(KERN_ERR "hugepagesz: Unsupported page size %lu M\n",
 180                         ps >> 20);
 181                 return 0;
 182         }
 183         return 1;
 184 }
 185 __setup("hugepagesz=", setup_hugepagesz);
 186 #endif