kernel/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 #else
  56
  57 /*
  58  * pmd_huge() returns 1 if @pmd is hugetlb related entry, that is normal
  59  * hugetlb entry or non-present (migration or hwpoisoned) hugetlb entry.
  60  * Otherwise, returns 0.
  61  */
  62 int pmd_huge(pmd_t pmd)
  63 {
  64         return !pmd_none(pmd) &&
  65                 (pmd_val(pmd) & (_PAGE_PRESENT|_PAGE_PSE)) != _PAGE_PRESENT;
  66 }
  67
  68 int pud_huge(pud_t pud)
  69 {
  70         return !!(pud_val(pud) & _PAGE_PSE);
  71 }
  72 #endif
  73
  74 #ifdef CONFIG_HUGETLB_PAGE
  75 static unsigned long hugetlb_get_unmapped_area_bottomup(struct file *file,
  76                 unsigned long addr, unsigned long len,
  77                 unsigned long pgoff, unsigned long flags)
  78 {
  79         struct hstate *h = hstate_file(file);
  80         struct vm_unmapped_area_info info;
  81
  82         info.flags = 0;
  83         info.length = len;
  84         info.low_limit = current->mm->mmap_legacy_base;
  85         info.high_limit = TASK_SIZE;
  86         info.align_mask = PAGE_MASK & ~huge_page_mask(h);
  87         info.align_offset = 0;
  88         return vm_unmapped_area(&info);
  89 }
  90
  91 static unsigned long hugetlb_get_unmapped_area_topdown(struct file *file,
  92                 unsigned long addr0, 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         unsigned long addr;
  98
  99         info.flags = VM_UNMAPPED_AREA_TOPDOWN;
 100         info.length = len;
 101         info.low_limit = PAGE_SIZE;
 102         info.high_limit = current->mm->mmap_base;
 103         info.align_mask = PAGE_MASK & ~huge_page_mask(h);
 104         info.align_offset = 0;
 105         addr = vm_unmapped_area(&info);
 106
 107         /*
 108          * A failed mmap() very likely causes application failure,
 109          * so fall back to the bottom-up function here. This scenario
 110          * can happen with large stack limits and large mmap()
 111          * allocations.
 112          */
 113         if (addr & ~PAGE_MASK) {
 114                 VM_BUG_ON(addr != -ENOMEM);
 115                 info.flags = 0;
 116                 info.low_limit = TASK_UNMAPPED_BASE;
 117                 info.high_limit = TASK_SIZE;
 118                 addr = vm_unmapped_area(&info);
 119         }
 120
 121         return addr;
 122 }
 123
 124 unsigned long
 125 hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
 126                 unsigned long len, unsigned long pgoff, unsigned long flags)
 127 {
 128         struct hstate *h = hstate_file(file);
 129         struct mm_struct *mm = current->mm;
 130         struct vm_area_struct *vma;
 131
 132         if (len & ~huge_page_mask(h))
 133                 return -EINVAL;
 134         if (len > TASK_SIZE)
 135                 return -ENOMEM;
 136
 137         if (flags & MAP_FIXED) {
 138                 if (prepare_hugepage_range(file, addr, len))
 139                         return -EINVAL;
 140                 return addr;
 141         }
 142
 143         if (addr) {
 144                 addr = ALIGN(addr, huge_page_size(h));
 145                 vma = find_vma(mm, addr);
 146                 if (TASK_SIZE - len >= addr &&
 147                     (!vma || addr + len <= vma->vm_start))
 148                         return addr;
 149         }
 150         if (mm->get_unmapped_area == arch_get_unmapped_area)
 151                 return hugetlb_get_unmapped_area_bottomup(file, addr, len,
 152                                 pgoff, flags);
 153         else
 154                 return hugetlb_get_unmapped_area_topdown(file, addr, len,
 155                                 pgoff, flags);
 156 }
 157 #endif /* CONFIG_HUGETLB_PAGE */
 158
 159 #ifdef CONFIG_X86_64
 160 static __init int setup_hugepagesz(char *opt)
 161 {
 162         unsigned long ps = memparse(opt, &opt);
 163         if (ps == PMD_SIZE) {
 164                 hugetlb_add_hstate(PMD_SHIFT - PAGE_SHIFT);
 165         } else if (ps == PUD_SIZE && cpu_has_gbpages) {
 166                 hugetlb_add_hstate(PUD_SHIFT - PAGE_SHIFT);
 167         } else {
 168                 printk(KERN_ERR "hugepagesz: Unsupported page size %lu M\n",
 169                         ps >> 20);
 170                 return 0;
 171         }
 172         return 1;
 173 }
 174 __setup("hugepagesz=", setup_hugepagesz);
 175
 176 #ifdef CONFIG_CMA
 177 static __init int gigantic_pages_init(void)
 178 {
 179         /* With CMA we can allocate gigantic pages at runtime */
 180         if (cpu_has_gbpages && !size_to_hstate(1UL << PUD_SHIFT))
 181                 hugetlb_add_hstate(PUD_SHIFT - PAGE_SHIFT);
 182         return 0;
 183 }
 184 arch_initcall(gigantic_pages_init);
 185 #endif
 186 #endif