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 /* x86_64 also uses this file */
  91
  92 #ifdef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
  93 static unsigned long hugetlb_get_unmapped_area_bottomup(struct file *file,
  94                 unsigned long addr, unsigned long len,
  95                 unsigned long pgoff, unsigned long flags)
  96 {
  97         struct hstate *h = hstate_file(file);
  98         struct vm_unmapped_area_info info;
  99
 100         info.flags = 0;
 101         info.length = len;
 102         info.low_limit = TASK_UNMAPPED_BASE;
 103         info.high_limit = TASK_SIZE;
 104         info.align_mask = PAGE_MASK & ~huge_page_mask(h);
 105         info.align_offset = 0;
 106         return vm_unmapped_area(&info);
 107 }
 108
 109 static unsigned long hugetlb_get_unmapped_area_topdown(struct file *file,
 110                 unsigned long addr0, unsigned long len,
 111                 unsigned long pgoff, unsigned long flags)
 112 {
 113         struct hstate *h = hstate_file(file);
 114         struct vm_unmapped_area_info info;
 115         unsigned long addr;
 116
 117         info.flags = VM_UNMAPPED_AREA_TOPDOWN;
 118         info.length = len;
 119         info.low_limit = PAGE_SIZE;
 120         info.high_limit = current->mm->mmap_base;
 121         info.align_mask = PAGE_MASK & ~huge_page_mask(h);
 122         info.align_offset = 0;
 123         addr = vm_unmapped_area(&info);
 124
 125         /*
 126          * A failed mmap() very likely causes application failure,
 127          * so fall back to the bottom-up function here. This scenario
 128          * can happen with large stack limits and large mmap()
 129          * allocations.
 130          */
 131         if (addr & ~PAGE_MASK) {
 132                 VM_BUG_ON(addr != -ENOMEM);
 133                 info.flags = 0;
 134                 info.low_limit = TASK_UNMAPPED_BASE;
 135                 info.high_limit = TASK_SIZE;
 136                 addr = vm_unmapped_area(&info);
 137         }
 138
 139         return addr;
 140 }
 141
 142 unsigned long
 143 hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
 144                 unsigned long len, unsigned long pgoff, unsigned long flags)
 145 {
 146         struct hstate *h = hstate_file(file);
 147         struct mm_struct *mm = current->mm;
 148         struct vm_area_struct *vma;
 149
 150         if (len & ~huge_page_mask(h))
 151                 return -EINVAL;
 152         if (len > TASK_SIZE)
 153                 return -ENOMEM;
 154
 155         if (flags & MAP_FIXED) {
 156                 if (prepare_hugepage_range(file, addr, len))
 157                         return -EINVAL;
 158                 return addr;
 159         }
 160
 161         if (addr) {
 162                 addr = ALIGN(addr, huge_page_size(h));
 163                 vma = find_vma(mm, addr);
 164                 if (TASK_SIZE - len >= addr &&
 165                     (!vma || addr + len <= vma->vm_start))
 166                         return addr;
 167         }
 168         if (mm->get_unmapped_area == arch_get_unmapped_area)
 169                 return hugetlb_get_unmapped_area_bottomup(file, addr, len,
 170                                 pgoff, flags);
 171         else
 172                 return hugetlb_get_unmapped_area_topdown(file, addr, len,
 173                                 pgoff, flags);
 174 }
 175
 176 #endif /*HAVE_ARCH_HUGETLB_UNMAPPED_AREA*/
 177
 178 #ifdef CONFIG_X86_64
 179 static __init int setup_hugepagesz(char *opt)
 180 {
 181         unsigned long ps = memparse(opt, &opt);
 182         if (ps == PMD_SIZE) {
 183                 hugetlb_add_hstate(PMD_SHIFT - PAGE_SHIFT);
 184         } else if (ps == PUD_SIZE && cpu_has_gbpages) {
 185                 hugetlb_add_hstate(PUD_SHIFT - PAGE_SHIFT);
 186         } else {
 187                 printk(KERN_ERR "hugepagesz: Unsupported page size %lu M\n",
 188                         ps >> 20);
 189                 return 0;
 190         }
 191         return 1;
 192 }
 193 __setup("hugepagesz=", setup_hugepagesz);
 194 #endif