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/pgalloc.h> 21 #include <asm/elf.h> 22 23 #if 0 /* This is just for testing */ 24 struct page * 25 follow_huge_addr(struct mm_struct *mm, unsigned long address, int write) 26 { 27 unsigned long start = address; 28 int length = 1; 29 int nr; 30 struct page *page; 31 struct vm_area_struct *vma; 32 33 vma = find_vma(mm, addr); 34 if (!vma || !is_vm_hugetlb_page(vma)) 35 return ERR_PTR(-EINVAL); 36 37 pte = huge_pte_offset(mm, address, vma_mmu_pagesize(vma)); 38 39 /* hugetlb should be locked, and hence, prefaulted */ 40 WARN_ON(!pte || pte_none(*pte)); 41 42 page = &pte_page(*pte)[vpfn % (HPAGE_SIZE/PAGE_SIZE)]; 43 44 WARN_ON(!PageHead(page)); 45 46 return page; 47 } 48 49 int pmd_huge(pmd_t pmd) 50 { 51 return 0; 52 } 53 54 int pud_huge(pud_t pud) 55 { 56 return 0; 57 } 58 59 #else 60 61 /* 62 * pmd_huge() returns 1 if @pmd is hugetlb related entry, that is normal 63 * hugetlb entry or non-present (migration or hwpoisoned) hugetlb entry. 64 * Otherwise, returns 0. 65 */ 66 int pmd_huge(pmd_t pmd) 67 { 68 return !pmd_none(pmd) && 69 (pmd_val(pmd) & (_PAGE_PRESENT|_PAGE_PSE)) != _PAGE_PRESENT; 70 } 71 72 int pud_huge(pud_t pud) 73 { 74 return !!(pud_val(pud) & _PAGE_PSE); 75 } 76 #endif 77 78 #ifdef CONFIG_HUGETLB_PAGE 79 static unsigned long hugetlb_get_unmapped_area_bottomup(struct file *file, 80 unsigned long addr, unsigned long len, 81 unsigned long pgoff, unsigned long flags) 82 { 83 struct hstate *h = hstate_file(file); 84 struct vm_unmapped_area_info info; 85 86 info.flags = 0; 87 info.length = len; 88 info.low_limit = get_mmap_base(1); 89 90 /* 91 * If hint address is above DEFAULT_MAP_WINDOW, look for unmapped area 92 * in the full address space. 93 */ 94 info.high_limit = in_32bit_syscall() ? 95 task_size_32bit() : task_size_64bit(addr > DEFAULT_MAP_WINDOW); 96 97 info.align_mask = PAGE_MASK & ~huge_page_mask(h); 98 info.align_offset = 0; 99 return vm_unmapped_area(&info); 100 } 101 102 static unsigned long hugetlb_get_unmapped_area_topdown(struct file *file, 103 unsigned long addr, unsigned long len, 104 unsigned long pgoff, unsigned long flags) 105 { 106 struct hstate *h = hstate_file(file); 107 struct vm_unmapped_area_info info; 108 109 info.flags = VM_UNMAPPED_AREA_TOPDOWN; 110 info.length = len; 111 info.low_limit = PAGE_SIZE; 112 info.high_limit = get_mmap_base(0); 113 114 /* 115 * If hint address is above DEFAULT_MAP_WINDOW, look for unmapped area 116 * in the full address space. 117 */ 118 if (addr > DEFAULT_MAP_WINDOW && !in_32bit_syscall()) 119 info.high_limit += TASK_SIZE_MAX - DEFAULT_MAP_WINDOW; 120 121 info.align_mask = PAGE_MASK & ~huge_page_mask(h); 122 info.align_offset = 0; 123 addr = vm_unmapped_area(&info); 124 125 /* 126 * A failed mmap() very likely causes application failure, 127 * so fall back to the bottom-up function here. This scenario 128 * can happen with large stack limits and large mmap() 129 * allocations. 130 */ 131 if (addr & ~PAGE_MASK) { 132 VM_BUG_ON(addr != -ENOMEM); 133 info.flags = 0; 134 info.low_limit = TASK_UNMAPPED_BASE; 135 info.high_limit = TASK_SIZE_LOW; 136 addr = vm_unmapped_area(&info); 137 } 138 139 return addr; 140 } 141 142 unsigned long 143 hugetlb_get_unmapped_area(struct file *file, unsigned long addr, 144 unsigned long len, unsigned long pgoff, unsigned long flags) 145 { 146 struct hstate *h = hstate_file(file); 147 struct mm_struct *mm = current->mm; 148 struct vm_area_struct *vma; 149 150 if (len & ~huge_page_mask(h)) 151 return -EINVAL; 152 153 if (len > TASK_SIZE) 154 return -ENOMEM; 155 156 /* No address checking. See comment at mmap_address_hint_valid() */ 157 if (flags & MAP_FIXED) { 158 if (prepare_hugepage_range(file, addr, len)) 159 return -EINVAL; 160 return addr; 161 } 162 163 if (addr) { 164 addr &= huge_page_mask(h); 165 if (!mmap_address_hint_valid(addr, len)) 166 goto get_unmapped_area; 167 168 vma = find_vma(mm, addr); 169 if (!vma || addr + len <= vm_start_gap(vma)) 170 return addr; 171 } 172 173 get_unmapped_area: 174 if (mm->get_unmapped_area == arch_get_unmapped_area) 175 return hugetlb_get_unmapped_area_bottomup(file, addr, len, 176 pgoff, flags); 177 else 178 return hugetlb_get_unmapped_area_topdown(file, addr, len, 179 pgoff, flags); 180 } 181 #endif /* CONFIG_HUGETLB_PAGE */ 182 183 #ifdef CONFIG_X86_64 184 static __init int setup_hugepagesz(char *opt) 185 { 186 unsigned long ps = memparse(opt, &opt); 187 if (ps == PMD_SIZE) { 188 hugetlb_add_hstate(PMD_SHIFT - PAGE_SHIFT); 189 } else if (ps == PUD_SIZE && boot_cpu_has(X86_FEATURE_GBPAGES)) { 190 hugetlb_add_hstate(PUD_SHIFT - PAGE_SHIFT); 191 } else { 192 hugetlb_bad_size(); 193 printk(KERN_ERR "hugepagesz: Unsupported page size %lu M\n", 194 ps >> 20); 195 return 0; 196 } 197 return 1; 198 } 199 __setup("hugepagesz=", setup_hugepagesz); 200 201 #ifdef CONFIG_CONTIG_ALLOC 202 static __init int gigantic_pages_init(void) 203 { 204 /* With compaction or CMA we can allocate gigantic pages at runtime */ 205 if (boot_cpu_has(X86_FEATURE_GBPAGES) && !size_to_hstate(1UL << PUD_SHIFT)) 206 hugetlb_add_hstate(PUD_SHIFT - PAGE_SHIFT); 207 return 0; 208 } 209 arch_initcall(gigantic_pages_init); 210 #endif 211 #endif 212