1 /* 2 * IA-32 Huge TLB Page Support for Kernel. 3 * 4 * Copyright (C) 2002, Rohit Seth <rohit.seth@intel.com> 5 */ 6 7 #include <linux/init.h> 8 #include <linux/fs.h> 9 #include <linux/mm.h> 10 #include <linux/sched/mm.h> 11 #include <linux/hugetlb.h> 12 #include <linux/pagemap.h> 13 #include <linux/err.h> 14 #include <linux/sysctl.h> 15 #include <asm/mman.h> 16 #include <asm/tlb.h> 17 #include <asm/tlbflush.h> 18 #include <asm/pgalloc.h> 19 20 #if 0 /* This is just for testing */ 21 struct page * 22 follow_huge_addr(struct mm_struct *mm, unsigned long address, int write) 23 { 24 unsigned long start = address; 25 int length = 1; 26 int nr; 27 struct page *page; 28 struct vm_area_struct *vma; 29 30 vma = find_vma(mm, addr); 31 if (!vma || !is_vm_hugetlb_page(vma)) 32 return ERR_PTR(-EINVAL); 33 34 pte = huge_pte_offset(mm, address); 35 36 /* hugetlb should be locked, and hence, prefaulted */ 37 WARN_ON(!pte || pte_none(*pte)); 38 39 page = &pte_page(*pte)[vpfn % (HPAGE_SIZE/PAGE_SIZE)]; 40 41 WARN_ON(!PageHead(page)); 42 43 return page; 44 } 45 46 int pmd_huge(pmd_t pmd) 47 { 48 return 0; 49 } 50 51 int pud_huge(pud_t pud) 52 { 53 return 0; 54 } 55 56 #else 57 58 /* 59 * pmd_huge() returns 1 if @pmd is hugetlb related entry, that is normal 60 * hugetlb entry or non-present (migration or hwpoisoned) hugetlb entry. 61 * Otherwise, returns 0. 62 */ 63 int pmd_huge(pmd_t pmd) 64 { 65 return !pmd_none(pmd) && 66 (pmd_val(pmd) & (_PAGE_PRESENT|_PAGE_PSE)) != _PAGE_PRESENT; 67 } 68 69 int pud_huge(pud_t pud) 70 { 71 return !!(pud_val(pud) & _PAGE_PSE); 72 } 73 #endif 74 75 #ifdef CONFIG_HUGETLB_PAGE 76 static unsigned long hugetlb_get_unmapped_area_bottomup(struct file *file, 77 unsigned long addr, unsigned long len, 78 unsigned long pgoff, unsigned long flags) 79 { 80 struct hstate *h = hstate_file(file); 81 struct vm_unmapped_area_info info; 82 83 info.flags = 0; 84 info.length = len; 85 info.low_limit = current->mm->mmap_legacy_base; 86 info.high_limit = TASK_SIZE; 87 info.align_mask = PAGE_MASK & ~huge_page_mask(h); 88 info.align_offset = 0; 89 return vm_unmapped_area(&info); 90 } 91 92 static unsigned long hugetlb_get_unmapped_area_topdown(struct file *file, 93 unsigned long addr0, unsigned long len, 94 unsigned long pgoff, unsigned long flags) 95 { 96 struct hstate *h = hstate_file(file); 97 struct vm_unmapped_area_info info; 98 unsigned long addr; 99 100 info.flags = VM_UNMAPPED_AREA_TOPDOWN; 101 info.length = len; 102 info.low_limit = PAGE_SIZE; 103 info.high_limit = current->mm->mmap_base; 104 info.align_mask = PAGE_MASK & ~huge_page_mask(h); 105 info.align_offset = 0; 106 addr = vm_unmapped_area(&info); 107 108 /* 109 * A failed mmap() very likely causes application failure, 110 * so fall back to the bottom-up function here. This scenario 111 * can happen with large stack limits and large mmap() 112 * allocations. 113 */ 114 if (addr & ~PAGE_MASK) { 115 VM_BUG_ON(addr != -ENOMEM); 116 info.flags = 0; 117 info.low_limit = TASK_UNMAPPED_BASE; 118 info.high_limit = TASK_SIZE; 119 addr = vm_unmapped_area(&info); 120 } 121 122 return addr; 123 } 124 125 unsigned long 126 hugetlb_get_unmapped_area(struct file *file, unsigned long addr, 127 unsigned long len, unsigned long pgoff, unsigned long flags) 128 { 129 struct hstate *h = hstate_file(file); 130 struct mm_struct *mm = current->mm; 131 struct vm_area_struct *vma; 132 133 if (len & ~huge_page_mask(h)) 134 return -EINVAL; 135 if (len > TASK_SIZE) 136 return -ENOMEM; 137 138 if (flags & MAP_FIXED) { 139 if (prepare_hugepage_range(file, addr, len)) 140 return -EINVAL; 141 return addr; 142 } 143 144 if (addr) { 145 addr = ALIGN(addr, huge_page_size(h)); 146 vma = find_vma(mm, addr); 147 if (TASK_SIZE - len >= addr && 148 (!vma || addr + len <= vma->vm_start)) 149 return addr; 150 } 151 if (mm->get_unmapped_area == arch_get_unmapped_area) 152 return hugetlb_get_unmapped_area_bottomup(file, addr, len, 153 pgoff, flags); 154 else 155 return hugetlb_get_unmapped_area_topdown(file, addr, len, 156 pgoff, flags); 157 } 158 #endif /* CONFIG_HUGETLB_PAGE */ 159 160 #ifdef CONFIG_X86_64 161 static __init int setup_hugepagesz(char *opt) 162 { 163 unsigned long ps = memparse(opt, &opt); 164 if (ps == PMD_SIZE) { 165 hugetlb_add_hstate(PMD_SHIFT - PAGE_SHIFT); 166 } else if (ps == PUD_SIZE && boot_cpu_has(X86_FEATURE_GBPAGES)) { 167 hugetlb_add_hstate(PUD_SHIFT - PAGE_SHIFT); 168 } else { 169 hugetlb_bad_size(); 170 printk(KERN_ERR "hugepagesz: Unsupported page size %lu M\n", 171 ps >> 20); 172 return 0; 173 } 174 return 1; 175 } 176 __setup("hugepagesz=", setup_hugepagesz); 177 178 #if (defined(CONFIG_MEMORY_ISOLATION) && defined(CONFIG_COMPACTION)) || defined(CONFIG_CMA) 179 static __init int gigantic_pages_init(void) 180 { 181 /* With compaction or CMA we can allocate gigantic pages at runtime */ 182 if (boot_cpu_has(X86_FEATURE_GBPAGES) && !size_to_hstate(1UL << PUD_SHIFT)) 183 hugetlb_add_hstate(PUD_SHIFT - PAGE_SHIFT); 184 return 0; 185 } 186 arch_initcall(gigantic_pages_init); 187 #endif 188 #endif 189