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/sched/mm.h>
  11 #include <linux/hugetlb.h>
  12 #include <linux/pagemap.h>
  13 #include <linux/err.h>
  14 #include <linux/sysctl.h>
  15 #include <asm/mman.h>
  16 #include <asm/tlb.h>
  17 #include <asm/tlbflush.h>
  18 #include <asm/pgalloc.h>
  19
  20 #if 0   /* This is just for testing */
  21 struct page *
  22 follow_huge_addr(struct mm_struct *mm, unsigned long address, int write)
  23 {
  24         unsigned long start = address;
  25         int length = 1;
  26         int nr;
  27         struct page *page;
  28         struct vm_area_struct *vma;
  29
  30         vma = find_vma(mm, addr);
  31         if (!vma || !is_vm_hugetlb_page(vma))
  32                 return ERR_PTR(-EINVAL);
  33
  34         pte = huge_pte_offset(mm, address);
  35
  36         /* hugetlb should be locked, and hence, prefaulted */
  37         WARN_ON(!pte || pte_none(*pte));
  38
  39         page = &pte_page(*pte)[vpfn % (HPAGE_SIZE/PAGE_SIZE)];
  40
  41         WARN_ON(!PageHead(page));
  42
  43         return page;
  44 }
  45
  46 int pmd_huge(pmd_t pmd)
  47 {
  48         return 0;
  49 }
  50
  51 int pud_huge(pud_t pud)
  52 {
  53         return 0;
  54 }
  55
  56 #else
  57
  58 /*
  59  * pmd_huge() returns 1 if @pmd is hugetlb related entry, that is normal
  60  * hugetlb entry or non-present (migration or hwpoisoned) hugetlb entry.
  61  * Otherwise, returns 0.
  62  */
  63 int pmd_huge(pmd_t pmd)
  64 {
  65         return !pmd_none(pmd) &&
  66                 (pmd_val(pmd) & (_PAGE_PRESENT|_PAGE_PSE)) != _PAGE_PRESENT;
  67 }
  68
  69 int pud_huge(pud_t pud)
  70 {
  71         return !!(pud_val(pud) & _PAGE_PSE);
  72 }
  73 #endif
  74
  75 #ifdef CONFIG_HUGETLB_PAGE
  76 static unsigned long hugetlb_get_unmapped_area_bottomup(struct file *file,
  77                 unsigned long addr, unsigned long len,
  78                 unsigned long pgoff, unsigned long flags)
  79 {
  80         struct hstate *h = hstate_file(file);
  81         struct vm_unmapped_area_info info;
  82
  83         info.flags = 0;
  84         info.length = len;
  85         info.low_limit = current->mm->mmap_legacy_base;
  86         info.high_limit = TASK_SIZE;
  87         info.align_mask = PAGE_MASK & ~huge_page_mask(h);
  88         info.align_offset = 0;
  89         return vm_unmapped_area(&info);
  90 }
  91
  92 static unsigned long hugetlb_get_unmapped_area_topdown(struct file *file,
  93                 unsigned long addr0, unsigned long len,
  94                 unsigned long pgoff, unsigned long flags)
  95 {
  96         struct hstate *h = hstate_file(file);
  97         struct vm_unmapped_area_info info;
  98         unsigned long addr;
  99
 100         info.flags = VM_UNMAPPED_AREA_TOPDOWN;
 101         info.length = len;
 102         info.low_limit = PAGE_SIZE;
 103         info.high_limit = current->mm->mmap_base;
 104         info.align_mask = PAGE_MASK & ~huge_page_mask(h);
 105         info.align_offset = 0;
 106         addr = vm_unmapped_area(&info);
 107
 108         /*
 109          * A failed mmap() very likely causes application failure,
 110          * so fall back to the bottom-up function here. This scenario
 111          * can happen with large stack limits and large mmap()
 112          * allocations.
 113          */
 114         if (addr & ~PAGE_MASK) {
 115                 VM_BUG_ON(addr != -ENOMEM);
 116                 info.flags = 0;
 117                 info.low_limit = TASK_UNMAPPED_BASE;
 118                 info.high_limit = TASK_SIZE;
 119                 addr = vm_unmapped_area(&info);
 120         }
 121
 122         return addr;
 123 }
 124
 125 unsigned long
 126 hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
 127                 unsigned long len, unsigned long pgoff, unsigned long flags)
 128 {
 129         struct hstate *h = hstate_file(file);
 130         struct mm_struct *mm = current->mm;
 131         struct vm_area_struct *vma;
 132
 133         if (len & ~huge_page_mask(h))
 134                 return -EINVAL;
 135         if (len > TASK_SIZE)
 136                 return -ENOMEM;
 137
 138         if (flags & MAP_FIXED) {
 139                 if (prepare_hugepage_range(file, addr, len))
 140                         return -EINVAL;
 141                 return addr;
 142         }
 143
 144         if (addr) {
 145                 addr = ALIGN(addr, huge_page_size(h));
 146                 vma = find_vma(mm, addr);
 147                 if (TASK_SIZE - len >= addr &&
 148                     (!vma || addr + len <= vma->vm_start))
 149                         return addr;
 150         }
 151         if (mm->get_unmapped_area == arch_get_unmapped_area)
 152                 return hugetlb_get_unmapped_area_bottomup(file, addr, len,
 153                                 pgoff, flags);
 154         else
 155                 return hugetlb_get_unmapped_area_topdown(file, addr, len,
 156                                 pgoff, flags);
 157 }
 158 #endif /* CONFIG_HUGETLB_PAGE */
 159
 160 #ifdef CONFIG_X86_64
 161 static __init int setup_hugepagesz(char *opt)
 162 {
 163         unsigned long ps = memparse(opt, &opt);
 164         if (ps == PMD_SIZE) {
 165                 hugetlb_add_hstate(PMD_SHIFT - PAGE_SHIFT);
 166         } else if (ps == PUD_SIZE && boot_cpu_has(X86_FEATURE_GBPAGES)) {
 167                 hugetlb_add_hstate(PUD_SHIFT - PAGE_SHIFT);
 168         } else {
 169                 hugetlb_bad_size();
 170                 printk(KERN_ERR "hugepagesz: Unsupported page size %lu M\n",
 171                         ps >> 20);
 172                 return 0;
 173         }
 174         return 1;
 175 }
 176 __setup("hugepagesz=", setup_hugepagesz);
 177
 178 #if (defined(CONFIG_MEMORY_ISOLATION) && defined(CONFIG_COMPACTION)) || defined(CONFIG_CMA)
 179 static __init int gigantic_pages_init(void)
 180 {
 181         /* With compaction or CMA we can allocate gigantic pages at runtime */
 182         if (boot_cpu_has(X86_FEATURE_GBPAGES) && !size_to_hstate(1UL << PUD_SHIFT))
 183                 hugetlb_add_hstate(PUD_SHIFT - PAGE_SHIFT);
 184         return 0;
 185 }
 186 arch_initcall(gigantic_pages_init);
 187 #endif
 188 #endif