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 <linux/compat.h>
  16 #include <asm/mman.h>
  17 #include <asm/tlb.h>
  18 #include <asm/tlbflush.h>
  19 #include <asm/pgalloc.h>
  20 #include <asm/elf.h>
  21
  22 #if 0   /* This is just for testing */
  23 struct page *
  24 follow_huge_addr(struct mm_struct *mm, unsigned long address, int write)
  25 {
  26         unsigned long start = address;
  27         int length = 1;
  28         int nr;
  29         struct page *page;
  30         struct vm_area_struct *vma;
  31
  32         vma = find_vma(mm, addr);
  33         if (!vma || !is_vm_hugetlb_page(vma))
  34                 return ERR_PTR(-EINVAL);
  35
  36         pte = huge_pte_offset(mm, address);
  37
  38         /* hugetlb should be locked, and hence, prefaulted */
  39         WARN_ON(!pte || pte_none(*pte));
  40
  41         page = &pte_page(*pte)[vpfn % (HPAGE_SIZE/PAGE_SIZE)];
  42
  43         WARN_ON(!PageHead(page));
  44
  45         return page;
  46 }
  47
  48 int pmd_huge(pmd_t pmd)
  49 {
  50         return 0;
  51 }
  52
  53 int pud_huge(pud_t pud)
  54 {
  55         return 0;
  56 }
  57
  58 #else
  59
  60 /*
  61  * pmd_huge() returns 1 if @pmd is hugetlb related entry, that is normal
  62  * hugetlb entry or non-present (migration or hwpoisoned) hugetlb entry.
  63  * Otherwise, returns 0.
  64  */
  65 int pmd_huge(pmd_t pmd)
  66 {
  67         return !pmd_none(pmd) &&
  68                 (pmd_val(pmd) & (_PAGE_PRESENT|_PAGE_PSE)) != _PAGE_PRESENT;
  69 }
  70
  71 int pud_huge(pud_t pud)
  72 {
  73         return !!(pud_val(pud) & _PAGE_PSE);
  74 }
  75 #endif
  76
  77 #ifdef CONFIG_HUGETLB_PAGE
  78 static unsigned long hugetlb_get_unmapped_area_bottomup(struct file *file,
  79                 unsigned long addr, unsigned long len,
  80                 unsigned long pgoff, unsigned long flags)
  81 {
  82         struct hstate *h = hstate_file(file);
  83         struct vm_unmapped_area_info info;
  84
  85         info.flags = 0;
  86         info.length = len;
  87         info.low_limit = get_mmap_base(1);
  88         info.high_limit = in_compat_syscall() ?
  89                 tasksize_32bit() : tasksize_64bit();
  90         info.align_mask = PAGE_MASK & ~huge_page_mask(h);
  91         info.align_offset = 0;
  92         return vm_unmapped_area(&info);
  93 }
  94
  95 static unsigned long hugetlb_get_unmapped_area_topdown(struct file *file,
  96                 unsigned long addr0, unsigned long len,
  97                 unsigned long pgoff, unsigned long flags)
  98 {
  99         struct hstate *h = hstate_file(file);
 100         struct vm_unmapped_area_info info;
 101         unsigned long addr;
 102
 103         info.flags = VM_UNMAPPED_AREA_TOPDOWN;
 104         info.length = len;
 105         info.low_limit = PAGE_SIZE;
 106         info.high_limit = get_mmap_base(0);
 107         info.align_mask = PAGE_MASK & ~huge_page_mask(h);
 108         info.align_offset = 0;
 109         addr = vm_unmapped_area(&info);
 110
 111         /*
 112          * A failed mmap() very likely causes application failure,
 113          * so fall back to the bottom-up function here. This scenario
 114          * can happen with large stack limits and large mmap()
 115          * allocations.
 116          */
 117         if (addr & ~PAGE_MASK) {
 118                 VM_BUG_ON(addr != -ENOMEM);
 119                 info.flags = 0;
 120                 info.low_limit = TASK_UNMAPPED_BASE;
 121                 info.high_limit = TASK_SIZE;
 122                 addr = vm_unmapped_area(&info);
 123         }
 124
 125         return addr;
 126 }
 127
 128 unsigned long
 129 hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
 130                 unsigned long len, unsigned long pgoff, unsigned long flags)
 131 {
 132         struct hstate *h = hstate_file(file);
 133         struct mm_struct *mm = current->mm;
 134         struct vm_area_struct *vma;
 135
 136         if (len & ~huge_page_mask(h))
 137                 return -EINVAL;
 138         if (len > TASK_SIZE)
 139                 return -ENOMEM;
 140
 141         if (flags & MAP_FIXED) {
 142                 if (prepare_hugepage_range(file, addr, len))
 143                         return -EINVAL;
 144                 return addr;
 145         }
 146
 147         if (addr) {
 148                 addr = ALIGN(addr, huge_page_size(h));
 149                 vma = find_vma(mm, addr);
 150                 if (TASK_SIZE - len >= addr &&
 151                     (!vma || addr + len <= vma->vm_start))
 152                         return addr;
 153         }
 154         if (mm->get_unmapped_area == arch_get_unmapped_area)
 155                 return hugetlb_get_unmapped_area_bottomup(file, addr, len,
 156                                 pgoff, flags);
 157         else
 158                 return hugetlb_get_unmapped_area_topdown(file, addr, len,
 159                                 pgoff, flags);
 160 }
 161 #endif /* CONFIG_HUGETLB_PAGE */
 162
 163 #ifdef CONFIG_X86_64
 164 static __init int setup_hugepagesz(char *opt)
 165 {
 166         unsigned long ps = memparse(opt, &opt);
 167         if (ps == PMD_SIZE) {
 168                 hugetlb_add_hstate(PMD_SHIFT - PAGE_SHIFT);
 169         } else if (ps == PUD_SIZE && boot_cpu_has(X86_FEATURE_GBPAGES)) {
 170                 hugetlb_add_hstate(PUD_SHIFT - PAGE_SHIFT);
 171         } else {
 172                 hugetlb_bad_size();
 173                 printk(KERN_ERR "hugepagesz: Unsupported page size %lu M\n",
 174                         ps >> 20);
 175                 return 0;
 176         }
 177         return 1;
 178 }
 179 __setup("hugepagesz=", setup_hugepagesz);
 180
 181 #if (defined(CONFIG_MEMORY_ISOLATION) && defined(CONFIG_COMPACTION)) || defined(CONFIG_CMA)
 182 static __init int gigantic_pages_init(void)
 183 {
 184         /* With compaction or CMA we can allocate gigantic pages at runtime */
 185         if (boot_cpu_has(X86_FEATURE_GBPAGES) && !size_to_hstate(1UL << PUD_SHIFT))
 186                 hugetlb_add_hstate(PUD_SHIFT - PAGE_SHIFT);
 187         return 0;
 188 }
 189 arch_initcall(gigantic_pages_init);
 190 #endif
 191 #endif