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 #ifdef CONFIG_HUGETLB_PAGE
  23 static unsigned long hugetlb_get_unmapped_area_bottomup(struct file *file,
  24                 unsigned long addr, unsigned long len,
  25                 unsigned long pgoff, unsigned long flags)
  26 {
  27         struct hstate *h = hstate_file(file);
  28         struct vm_unmapped_area_info info = {};
  29
  30         info.length = len;
  31         info.low_limit = get_mmap_base(1);
  32
  33         /*
  34          * If hint address is above DEFAULT_MAP_WINDOW, look for unmapped area
  35          * in the full address space.
  36          */
  37         info.high_limit = in_32bit_syscall() ?
  38                 task_size_32bit() : task_size_64bit(addr > DEFAULT_MAP_WINDOW);
  39
  40         info.align_mask = PAGE_MASK & ~huge_page_mask(h);
  41         return vm_unmapped_area(&info);
  42 }
  43
  44 static unsigned long hugetlb_get_unmapped_area_topdown(struct file *file,
  45                 unsigned long addr, unsigned long len,
  46                 unsigned long pgoff, unsigned long flags)
  47 {
  48         struct hstate *h = hstate_file(file);
  49         struct vm_unmapped_area_info info = {};
  50
  51         info.flags = VM_UNMAPPED_AREA_TOPDOWN;
  52         info.length = len;
  53         info.low_limit = PAGE_SIZE;
  54         info.high_limit = get_mmap_base(0);
  55
  56         /*
  57          * If hint address is above DEFAULT_MAP_WINDOW, look for unmapped area
  58          * in the full address space.
  59          */
  60         if (addr > DEFAULT_MAP_WINDOW && !in_32bit_syscall())
  61                 info.high_limit += TASK_SIZE_MAX - DEFAULT_MAP_WINDOW;
  62
  63         info.align_mask = PAGE_MASK & ~huge_page_mask(h);
  64         addr = vm_unmapped_area(&info);
  65
  66         /*
  67          * A failed mmap() very likely causes application failure,
  68          * so fall back to the bottom-up function here. This scenario
  69          * can happen with large stack limits and large mmap()
  70          * allocations.
  71          */
  72         if (addr & ~PAGE_MASK) {
  73                 VM_BUG_ON(addr != -ENOMEM);
  74                 info.flags = 0;
  75                 info.low_limit = TASK_UNMAPPED_BASE;
  76                 info.high_limit = TASK_SIZE_LOW;
  77                 addr = vm_unmapped_area(&info);
  78         }
  79
  80         return addr;
  81 }
  82
  83 unsigned long
  84 hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
  85                 unsigned long len, unsigned long pgoff, unsigned long flags)
  86 {
  87         struct hstate *h = hstate_file(file);
  88         struct mm_struct *mm = current->mm;
  89         struct vm_area_struct *vma;
  90
  91         if (len & ~huge_page_mask(h))
  92                 return -EINVAL;
  93
  94         if (len > TASK_SIZE)
  95                 return -ENOMEM;
  96
  97         /* No address checking. See comment at mmap_address_hint_valid() */
  98         if (flags & MAP_FIXED) {
  99                 if (prepare_hugepage_range(file, addr, len))
 100                         return -EINVAL;
 101                 return addr;
 102         }
 103
 104         if (addr) {
 105                 addr &= huge_page_mask(h);
 106                 if (!mmap_address_hint_valid(addr, len))
 107                         goto get_unmapped_area;
 108
 109                 vma = find_vma(mm, addr);
 110                 if (!vma || addr + len <= vm_start_gap(vma))
 111                         return addr;
 112         }
 113
 114 get_unmapped_area:
 115         if (!test_bit(MMF_TOPDOWN, &mm->flags))
 116                 return hugetlb_get_unmapped_area_bottomup(file, addr, len,
 117                                 pgoff, flags);
 118         else
 119                 return hugetlb_get_unmapped_area_topdown(file, addr, len,
 120                                 pgoff, flags);
 121 }
 122 #endif /* CONFIG_HUGETLB_PAGE */
 123
 124 #ifdef CONFIG_X86_64
 125 bool __init arch_hugetlb_valid_size(unsigned long size)
 126 {
 127         if (size == PMD_SIZE)
 128                 return true;
 129         else if (size == PUD_SIZE && boot_cpu_has(X86_FEATURE_GBPAGES))
 130                 return true;
 131         else
 132                 return false;
 133 }
 134
 135 #ifdef CONFIG_CONTIG_ALLOC
 136 static __init int gigantic_pages_init(void)
 137 {
 138         /* With compaction or CMA we can allocate gigantic pages at runtime */
 139         if (boot_cpu_has(X86_FEATURE_GBPAGES))
 140                 hugetlb_add_hstate(PUD_SHIFT - PAGE_SHIFT);
 141         return 0;
 142 }
 143 arch_initcall(gigantic_pages_init);
 144 #endif
 145 #endif