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         return !pud_none(pud) &&
  41                 (pud_val(pud) & (_PAGE_PRESENT|_PAGE_PSE)) != _PAGE_PRESENT;
  42 }
  43
  44 #ifdef CONFIG_HUGETLB_PAGE
  45 static unsigned long hugetlb_get_unmapped_area_bottomup(struct file *file,
  46                 unsigned long addr, unsigned long len,
  47                 unsigned long pgoff, unsigned long flags)
  48 {
  49         struct hstate *h = hstate_file(file);
  50         struct vm_unmapped_area_info info;
  51
  52         info.flags = 0;
  53         info.length = len;
  54         info.low_limit = get_mmap_base(1);
  55
  56         /*
  57          * If hint address is above DEFAULT_MAP_WINDOW, look for unmapped area
  58          * in the full address space.
  59          */
  60         info.high_limit = in_32bit_syscall() ?
  61                 task_size_32bit() : task_size_64bit(addr > DEFAULT_MAP_WINDOW);
  62
  63         info.align_mask = PAGE_MASK & ~huge_page_mask(h);
  64         info.align_offset = 0;
  65         return vm_unmapped_area(&info);
  66 }
  67
  68 static unsigned long hugetlb_get_unmapped_area_topdown(struct file *file,
  69                 unsigned long addr, unsigned long len,
  70                 unsigned long pgoff, unsigned long flags)
  71 {
  72         struct hstate *h = hstate_file(file);
  73         struct vm_unmapped_area_info info;
  74
  75         info.flags = VM_UNMAPPED_AREA_TOPDOWN;
  76         info.length = len;
  77         info.low_limit = PAGE_SIZE;
  78         info.high_limit = get_mmap_base(0);
  79
  80         /*
  81          * If hint address is above DEFAULT_MAP_WINDOW, look for unmapped area
  82          * in the full address space.
  83          */
  84         if (addr > DEFAULT_MAP_WINDOW && !in_32bit_syscall())
  85                 info.high_limit += TASK_SIZE_MAX - DEFAULT_MAP_WINDOW;
  86
  87         info.align_mask = PAGE_MASK & ~huge_page_mask(h);
  88         info.align_offset = 0;
  89         addr = vm_unmapped_area(&info);
  90
  91         /*
  92          * A failed mmap() very likely causes application failure,
  93          * so fall back to the bottom-up function here. This scenario
  94          * can happen with large stack limits and large mmap()
  95          * allocations.
  96          */
  97         if (addr & ~PAGE_MASK) {
  98                 VM_BUG_ON(addr != -ENOMEM);
  99                 info.flags = 0;
 100                 info.low_limit = TASK_UNMAPPED_BASE;
 101                 info.high_limit = TASK_SIZE_LOW;
 102                 addr = vm_unmapped_area(&info);
 103         }
 104
 105         return addr;
 106 }
 107
 108 unsigned long
 109 hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
 110                 unsigned long len, unsigned long pgoff, unsigned long flags)
 111 {
 112         struct hstate *h = hstate_file(file);
 113         struct mm_struct *mm = current->mm;
 114         struct vm_area_struct *vma;
 115
 116         if (len & ~huge_page_mask(h))
 117                 return -EINVAL;
 118
 119         if (len > TASK_SIZE)
 120                 return -ENOMEM;
 121
 122         /* No address checking. See comment at mmap_address_hint_valid() */
 123         if (flags & MAP_FIXED) {
 124                 if (prepare_hugepage_range(file, addr, len))
 125                         return -EINVAL;
 126                 return addr;
 127         }
 128
 129         if (addr) {
 130                 addr &= huge_page_mask(h);
 131                 if (!mmap_address_hint_valid(addr, len))
 132                         goto get_unmapped_area;
 133
 134                 vma = find_vma(mm, addr);
 135                 if (!vma || addr + len <= vm_start_gap(vma))
 136                         return addr;
 137         }
 138
 139 get_unmapped_area:
 140         if (mm->get_unmapped_area == arch_get_unmapped_area)
 141                 return hugetlb_get_unmapped_area_bottomup(file, addr, len,
 142                                 pgoff, flags);
 143         else
 144                 return hugetlb_get_unmapped_area_topdown(file, addr, len,
 145                                 pgoff, flags);
 146 }
 147 #endif /* CONFIG_HUGETLB_PAGE */
 148
 149 #ifdef CONFIG_X86_64
 150 bool __init arch_hugetlb_valid_size(unsigned long size)
 151 {
 152         if (size == PMD_SIZE)
 153                 return true;
 154         else if (size == PUD_SIZE && boot_cpu_has(X86_FEATURE_GBPAGES))
 155                 return true;
 156         else
 157                 return false;
 158 }
 159
 160 #ifdef CONFIG_CONTIG_ALLOC
 161 static __init int gigantic_pages_init(void)
 162 {
 163         /* With compaction or CMA we can allocate gigantic pages at runtime */
 164         if (boot_cpu_has(X86_FEATURE_GBPAGES))
 165                 hugetlb_add_hstate(PUD_SHIFT - PAGE_SHIFT);
 166         return 0;
 167 }
 168 arch_initcall(gigantic_pages_init);
 169 #endif
 170 #endif