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 #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, vma_mmu_pagesize(vma)); 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 89 /* 90 * If hint address is above DEFAULT_MAP_WINDOW, look for unmapped area 91 * in the full address space. 92 */ 93 info.high_limit = in_32bit_syscall() ? 94 task_size_32bit() : task_size_64bit(addr > DEFAULT_MAP_WINDOW); 95 96 info.align_mask = PAGE_MASK & ~huge_page_mask(h); 97 info.align_offset = 0; 98 return vm_unmapped_area(&info); 99 } 100 101 static unsigned long hugetlb_get_unmapped_area_topdown(struct file *file, 102 unsigned long addr, unsigned long len, 103 unsigned long pgoff, unsigned long flags) 104 { 105 struct hstate *h = hstate_file(file); 106 struct vm_unmapped_area_info info; 107 108 info.flags = VM_UNMAPPED_AREA_TOPDOWN; 109 info.length = len; 110 info.low_limit = PAGE_SIZE; 111 info.high_limit = get_mmap_base(0); 112 113 /* 114 * If hint address is above DEFAULT_MAP_WINDOW, look for unmapped area 115 * in the full address space. 116 */ 117 if (addr > DEFAULT_MAP_WINDOW && !in_32bit_syscall()) 118 info.high_limit += TASK_SIZE_MAX - DEFAULT_MAP_WINDOW; 119 120 info.align_mask = PAGE_MASK & ~huge_page_mask(h); 121 info.align_offset = 0; 122 addr = vm_unmapped_area(&info); 123 124 /* 125 * A failed mmap() very likely causes application failure, 126 * so fall back to the bottom-up function here. This scenario 127 * can happen with large stack limits and large mmap() 128 * allocations. 129 */ 130 if (addr & ~PAGE_MASK) { 131 VM_BUG_ON(addr != -ENOMEM); 132 info.flags = 0; 133 info.low_limit = TASK_UNMAPPED_BASE; 134 info.high_limit = TASK_SIZE_LOW; 135 addr = vm_unmapped_area(&info); 136 } 137 138 return addr; 139 } 140 141 unsigned long 142 hugetlb_get_unmapped_area(struct file *file, unsigned long addr, 143 unsigned long len, unsigned long pgoff, unsigned long flags) 144 { 145 struct hstate *h = hstate_file(file); 146 struct mm_struct *mm = current->mm; 147 struct vm_area_struct *vma; 148 149 if (len & ~huge_page_mask(h)) 150 return -EINVAL; 151 152 if (len > TASK_SIZE) 153 return -ENOMEM; 154 155 /* No address checking. See comment at mmap_address_hint_valid() */ 156 if (flags & MAP_FIXED) { 157 if (prepare_hugepage_range(file, addr, len)) 158 return -EINVAL; 159 return addr; 160 } 161 162 if (addr) { 163 addr &= huge_page_mask(h); 164 if (!mmap_address_hint_valid(addr, len)) 165 goto get_unmapped_area; 166 167 vma = find_vma(mm, addr); 168 if (!vma || addr + len <= vm_start_gap(vma)) 169 return addr; 170 } 171 172 get_unmapped_area: 173 if (mm->get_unmapped_area == arch_get_unmapped_area) 174 return hugetlb_get_unmapped_area_bottomup(file, addr, len, 175 pgoff, flags); 176 else 177 return hugetlb_get_unmapped_area_topdown(file, addr, len, 178 pgoff, flags); 179 } 180 #endif /* CONFIG_HUGETLB_PAGE */ 181 182 #ifdef CONFIG_X86_64 183 bool __init arch_hugetlb_valid_size(unsigned long size) 184 { 185 if (size == PMD_SIZE) 186 return true; 187 else if (size == PUD_SIZE && boot_cpu_has(X86_FEATURE_GBPAGES)) 188 return true; 189 else 190 return false; 191 } 192 193 #ifdef CONFIG_CONTIG_ALLOC 194 static __init int gigantic_pages_init(void) 195 { 196 /* With compaction or CMA we can allocate gigantic pages at runtime */ 197 if (boot_cpu_has(X86_FEATURE_GBPAGES)) 198 hugetlb_add_hstate(PUD_SHIFT - PAGE_SHIFT); 199 return 0; 200 } 201 arch_initcall(gigantic_pages_init); 202 #endif 203 #endif 204