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 #include <asm/mpx.h> 23 24 #if 0 /* This is just for testing */ 25 struct page * 26 follow_huge_addr(struct mm_struct *mm, unsigned long address, int write) 27 { 28 unsigned long start = address; 29 int length = 1; 30 int nr; 31 struct page *page; 32 struct vm_area_struct *vma; 33 34 vma = find_vma(mm, addr); 35 if (!vma || !is_vm_hugetlb_page(vma)) 36 return ERR_PTR(-EINVAL); 37 38 pte = huge_pte_offset(mm, address, vma_mmu_pagesize(vma)); 39 40 /* hugetlb should be locked, and hence, prefaulted */ 41 WARN_ON(!pte || pte_none(*pte)); 42 43 page = &pte_page(*pte)[vpfn % (HPAGE_SIZE/PAGE_SIZE)]; 44 45 WARN_ON(!PageHead(page)); 46 47 return page; 48 } 49 50 int pmd_huge(pmd_t pmd) 51 { 52 return 0; 53 } 54 55 int pud_huge(pud_t pud) 56 { 57 return 0; 58 } 59 60 #else 61 62 /* 63 * pmd_huge() returns 1 if @pmd is hugetlb related entry, that is normal 64 * hugetlb entry or non-present (migration or hwpoisoned) hugetlb entry. 65 * Otherwise, returns 0. 66 */ 67 int pmd_huge(pmd_t pmd) 68 { 69 return !pmd_none(pmd) && 70 (pmd_val(pmd) & (_PAGE_PRESENT|_PAGE_PSE)) != _PAGE_PRESENT; 71 } 72 73 int pud_huge(pud_t pud) 74 { 75 return !!(pud_val(pud) & _PAGE_PSE); 76 } 77 #endif 78 79 #ifdef CONFIG_HUGETLB_PAGE 80 static unsigned long hugetlb_get_unmapped_area_bottomup(struct file *file, 81 unsigned long addr, unsigned long len, 82 unsigned long pgoff, unsigned long flags) 83 { 84 struct hstate *h = hstate_file(file); 85 struct vm_unmapped_area_info info; 86 87 info.flags = 0; 88 info.length = len; 89 info.low_limit = get_mmap_base(1); 90 91 /* 92 * If hint address is above DEFAULT_MAP_WINDOW, look for unmapped area 93 * in the full address space. 94 */ 95 info.high_limit = in_compat_syscall() ? 96 task_size_32bit() : task_size_64bit(addr > DEFAULT_MAP_WINDOW); 97 98 info.align_mask = PAGE_MASK & ~huge_page_mask(h); 99 info.align_offset = 0; 100 return vm_unmapped_area(&info); 101 } 102 103 static unsigned long hugetlb_get_unmapped_area_topdown(struct file *file, 104 unsigned long addr, unsigned long len, 105 unsigned long pgoff, unsigned long flags) 106 { 107 struct hstate *h = hstate_file(file); 108 struct vm_unmapped_area_info info; 109 110 info.flags = VM_UNMAPPED_AREA_TOPDOWN; 111 info.length = len; 112 info.low_limit = PAGE_SIZE; 113 info.high_limit = get_mmap_base(0); 114 115 /* 116 * If hint address is above DEFAULT_MAP_WINDOW, look for unmapped area 117 * in the full address space. 118 */ 119 if (addr > DEFAULT_MAP_WINDOW && !in_compat_syscall()) 120 info.high_limit += TASK_SIZE_MAX - DEFAULT_MAP_WINDOW; 121 122 info.align_mask = PAGE_MASK & ~huge_page_mask(h); 123 info.align_offset = 0; 124 addr = vm_unmapped_area(&info); 125 126 /* 127 * A failed mmap() very likely causes application failure, 128 * so fall back to the bottom-up function here. This scenario 129 * can happen with large stack limits and large mmap() 130 * allocations. 131 */ 132 if (addr & ~PAGE_MASK) { 133 VM_BUG_ON(addr != -ENOMEM); 134 info.flags = 0; 135 info.low_limit = TASK_UNMAPPED_BASE; 136 info.high_limit = TASK_SIZE_LOW; 137 addr = vm_unmapped_area(&info); 138 } 139 140 return addr; 141 } 142 143 unsigned long 144 hugetlb_get_unmapped_area(struct file *file, unsigned long addr, 145 unsigned long len, unsigned long pgoff, unsigned long flags) 146 { 147 struct hstate *h = hstate_file(file); 148 struct mm_struct *mm = current->mm; 149 struct vm_area_struct *vma; 150 151 if (len & ~huge_page_mask(h)) 152 return -EINVAL; 153 154 addr = mpx_unmapped_area_check(addr, len, flags); 155 if (IS_ERR_VALUE(addr)) 156 return addr; 157 158 if (len > TASK_SIZE) 159 return -ENOMEM; 160 161 if (flags & MAP_FIXED) { 162 if (prepare_hugepage_range(file, addr, len)) 163 return -EINVAL; 164 return addr; 165 } 166 167 if (addr) { 168 addr = ALIGN(addr, huge_page_size(h)); 169 vma = find_vma(mm, addr); 170 if (TASK_SIZE - len >= addr && 171 (!vma || addr + len <= vm_start_gap(vma))) 172 return addr; 173 } 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 #if (defined(CONFIG_MEMORY_ISOLATION) && defined(CONFIG_COMPACTION)) || defined(CONFIG_CMA) 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