arch/x86/mm/hugetlbpage.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * IA-32 Huge TLB Page Support for Kernel.
   4  *
   5  * Copyright (C) 2002, Rohit Seth <rohit.seth@intel.com>
   6  */
   7
   8 #include <linux/init.h>
   9 #include <linux/fs.h>
  10 #include <linux/mm.h>
  11 #include <linux/sched/mm.h>
  12 #include <linux/hugetlb.h>
  13 #include <linux/pagemap.h>
  14 #include <linux/err.h>
  15 #include <linux/sysctl.h>
  16 #include <linux/compat.h>
  17 #include <asm/mman.h>
  18 #include <asm/tlb.h>
  19 #include <asm/tlbflush.h>
  20 #include <asm/elf.h>
  21
  22 /*
  23  * pmd_huge() returns 1 if @pmd is hugetlb related entry, that is normal
  24  * hugetlb entry or non-present (migration or hwpoisoned) hugetlb entry.
  25  * Otherwise, returns 0.
  26  */
  27 int pmd_huge(pmd_t pmd)
  28 {
  29         return !pmd_none(pmd) &&
  30                 (pmd_val(pmd) & (_PAGE_PRESENT|_PAGE_PSE)) != _PAGE_PRESENT;
  31 }
  32
  33 /*
  34  * pud_huge() returns 1 if @pud is hugetlb related entry, that is normal
  35  * hugetlb entry or non-present (migration or hwpoisoned) hugetlb entry.
  36  * Otherwise, returns 0.
  37  */
  38 int pud_huge(pud_t pud)
  39 {
  40 #if CONFIG_PGTABLE_LEVELS > 2
  41         return !pud_none(pud) &&
  42                 (pud_val(pud) & (_PAGE_PRESENT|_PAGE_PSE)) != _PAGE_PRESENT;
  43 #else
  44         return 0;
  45 #endif
  46 }
  47
  48 #ifdef CONFIG_HUGETLB_PAGE
  49 static unsigned long hugetlb_get_unmapped_area_bottomup(struct file *file,
  50                 unsigned long addr, unsigned long len,
  51                 unsigned long pgoff, unsigned long flags)
  52 {
  53         struct hstate *h = hstate_file(file);
  54         struct vm_unmapped_area_info info;
  55
  56         info.flags = 0;
  57         info.length = len;
  58         info.low_limit = get_mmap_base(1);
  59
  60         /*
  61          * If hint address is above DEFAULT_MAP_WINDOW, look for unmapped area
  62          * in the full address space.
  63          */
  64         info.high_limit = in_32bit_syscall() ?
  65                 task_size_32bit() : task_size_64bit(addr > DEFAULT_MAP_WINDOW);
  66
  67         info.align_mask = PAGE_MASK & ~huge_page_mask(h);
  68         info.align_offset = 0;
  69         return vm_unmapped_area(&info);
  70 }
  71
  72 static unsigned long hugetlb_get_unmapped_area_topdown(struct file *file,
  73                 unsigned long addr, unsigned long len,
  74                 unsigned long pgoff, unsigned long flags)
  75 {
  76         struct hstate *h = hstate_file(file);
  77         struct vm_unmapped_area_info info;
  78
  79         info.flags = VM_UNMAPPED_AREA_TOPDOWN;
  80         info.length = len;
  81         info.low_limit = PAGE_SIZE;
  82         info.high_limit = get_mmap_base(0);
  83
  84         /*
  85          * If hint address is above DEFAULT_MAP_WINDOW, look for unmapped area
  86          * in the full address space.
  87          */
  88         if (addr > DEFAULT_MAP_WINDOW && !in_32bit_syscall())
  89                 info.high_limit += TASK_SIZE_MAX - DEFAULT_MAP_WINDOW;
  90
  91         info.align_mask = PAGE_MASK & ~huge_page_mask(h);
  92         info.align_offset = 0;
  93         addr = vm_unmapped_area(&info);
  94
  95         /*
  96          * A failed mmap() very likely causes application failure,
  97          * so fall back to the bottom-up function here. This scenario
  98          * can happen with large stack limits and large mmap()
  99          * allocations.
 100          */
 101         if (addr & ~PAGE_MASK) {
 102                 VM_BUG_ON(addr != -ENOMEM);
 103                 info.flags = 0;
 104                 info.low_limit = TASK_UNMAPPED_BASE;
 105                 info.high_limit = TASK_SIZE_LOW;
 106                 addr = vm_unmapped_area(&info);
 107         }
 108
 109         return addr;
 110 }
 111
 112 unsigned long
 113 hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
 114                 unsigned long len, unsigned long pgoff, unsigned long flags)
 115 {
 116         struct hstate *h = hstate_file(file);
 117         struct mm_struct *mm = current->mm;
 118         struct vm_area_struct *vma;
 119
 120         if (len & ~huge_page_mask(h))
 121                 return -EINVAL;
 122
 123         if (len > TASK_SIZE)
 124                 return -ENOMEM;
 125
 126         /* No address checking. See comment at mmap_address_hint_valid() */
 127         if (flags & MAP_FIXED) {
 128                 if (prepare_hugepage_range(file, addr, len))
 129                         return -EINVAL;
 130                 return addr;
 131         }
 132
 133         if (addr) {
 134                 addr &= huge_page_mask(h);
 135                 if (!mmap_address_hint_valid(addr, len))
 136                         goto get_unmapped_area;
 137
 138                 vma = find_vma(mm, addr);
 139                 if (!vma || addr + len <= vm_start_gap(vma))
 140                         return addr;
 141         }
 142
 143 get_unmapped_area:
 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 bool __init arch_hugetlb_valid_size(unsigned long size)
 155 {
 156         if (size == PMD_SIZE)
 157                 return true;
 158         else if (size == PUD_SIZE && boot_cpu_has(X86_FEATURE_GBPAGES))
 159                 return true;
 160         else
 161                 return false;
 162 }
 163
 164 #ifdef CONFIG_CONTIG_ALLOC
 165 static __init int gigantic_pages_init(void)
 166 {
 167         /* With compaction or CMA we can allocate gigantic pages at runtime */
 168         if (boot_cpu_has(X86_FEATURE_GBPAGES))
 169                 hugetlb_add_hstate(PUD_SHIFT - PAGE_SHIFT);
 170         return 0;
 171 }
 172 arch_initcall(gigantic_pages_init);
 173 #endif
 174 #endif