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