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 int pud_huge(pud_t pud)
  34 {
  35         return !!(pud_val(pud) & _PAGE_PSE);
  36 }
  37
  38 #ifdef CONFIG_HUGETLB_PAGE
  39 static unsigned long hugetlb_get_unmapped_area_bottomup(struct file *file,
  40                 unsigned long addr, unsigned long len,
  41                 unsigned long pgoff, unsigned long flags)
  42 {
  43         struct hstate *h = hstate_file(file);
  44         struct vm_unmapped_area_info info;
  45
  46         info.flags = 0;
  47         info.length = len;
  48         info.low_limit = get_mmap_base(1);
  49
  50         /*
  51          * If hint address is above DEFAULT_MAP_WINDOW, look for unmapped area
  52          * in the full address space.
  53          */
  54         info.high_limit = in_32bit_syscall() ?
  55                 task_size_32bit() : task_size_64bit(addr > DEFAULT_MAP_WINDOW);
  56
  57         info.align_mask = PAGE_MASK & ~huge_page_mask(h);
  58         info.align_offset = 0;
  59         return vm_unmapped_area(&info);
  60 }
  61
  62 static unsigned long hugetlb_get_unmapped_area_topdown(struct file *file,
  63                 unsigned long addr, unsigned long len,
  64                 unsigned long pgoff, unsigned long flags)
  65 {
  66         struct hstate *h = hstate_file(file);
  67         struct vm_unmapped_area_info info;
  68
  69         info.flags = VM_UNMAPPED_AREA_TOPDOWN;
  70         info.length = len;
  71         info.low_limit = PAGE_SIZE;
  72         info.high_limit = get_mmap_base(0);
  73
  74         /*
  75          * If hint address is above DEFAULT_MAP_WINDOW, look for unmapped area
  76          * in the full address space.
  77          */
  78         if (addr > DEFAULT_MAP_WINDOW && !in_32bit_syscall())
  79                 info.high_limit += TASK_SIZE_MAX - DEFAULT_MAP_WINDOW;
  80
  81         info.align_mask = PAGE_MASK & ~huge_page_mask(h);
  82         info.align_offset = 0;
  83         addr = vm_unmapped_area(&info);
  84
  85         /*
  86          * A failed mmap() very likely causes application failure,
  87          * so fall back to the bottom-up function here. This scenario
  88          * can happen with large stack limits and large mmap()
  89          * allocations.
  90          */
  91         if (addr & ~PAGE_MASK) {
  92                 VM_BUG_ON(addr != -ENOMEM);
  93                 info.flags = 0;
  94                 info.low_limit = TASK_UNMAPPED_BASE;
  95                 info.high_limit = TASK_SIZE_LOW;
  96                 addr = vm_unmapped_area(&info);
  97         }
  98
  99         return addr;
 100 }
 101
 102 unsigned long
 103 hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
 104                 unsigned long len, unsigned long pgoff, unsigned long flags)
 105 {
 106         struct hstate *h = hstate_file(file);
 107         struct mm_struct *mm = current->mm;
 108         struct vm_area_struct *vma;
 109
 110         if (len & ~huge_page_mask(h))
 111                 return -EINVAL;
 112
 113         if (len > TASK_SIZE)
 114                 return -ENOMEM;
 115
 116         /* No address checking. See comment at mmap_address_hint_valid() */
 117         if (flags & MAP_FIXED) {
 118                 if (prepare_hugepage_range(file, addr, len))
 119                         return -EINVAL;
 120                 return addr;
 121         }
 122
 123         if (addr) {
 124                 addr &= huge_page_mask(h);
 125                 if (!mmap_address_hint_valid(addr, len))
 126                         goto get_unmapped_area;
 127
 128                 vma = find_vma(mm, addr);
 129                 if (!vma || addr + len <= vm_start_gap(vma))
 130                         return addr;
 131         }
 132
 133 get_unmapped_area:
 134         if (mm->get_unmapped_area == arch_get_unmapped_area)
 135                 return hugetlb_get_unmapped_area_bottomup(file, addr, len,
 136                                 pgoff, flags);
 137         else
 138                 return hugetlb_get_unmapped_area_topdown(file, addr, len,
 139                                 pgoff, flags);
 140 }
 141 #endif /* CONFIG_HUGETLB_PAGE */
 142
 143 #ifdef CONFIG_X86_64
 144 bool __init arch_hugetlb_valid_size(unsigned long size)
 145 {
 146         if (size == PMD_SIZE)
 147                 return true;
 148         else if (size == PUD_SIZE && boot_cpu_has(X86_FEATURE_GBPAGES))
 149                 return true;
 150         else
 151                 return false;
 152 }
 153
 154 #ifdef CONFIG_CONTIG_ALLOC
 155 static __init int gigantic_pages_init(void)
 156 {
 157         /* With compaction or CMA we can allocate gigantic pages at runtime */
 158         if (boot_cpu_has(X86_FEATURE_GBPAGES))
 159                 hugetlb_add_hstate(PUD_SHIFT - PAGE_SHIFT);
 160         return 0;
 161 }
 162 arch_initcall(gigantic_pages_init);
 163 #endif
 164 #endif