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/hugetlb.h> 11 #include <linux/pagemap.h> 12 #include <linux/err.h> 13 #include <linux/sysctl.h> 14 #include <asm/mman.h> 15 #include <asm/tlb.h> 16 #include <asm/tlbflush.h> 17 #include <asm/pgalloc.h> 18 19 #if 0 /* This is just for testing */ 20 struct page * 21 follow_huge_addr(struct mm_struct *mm, unsigned long address, int write) 22 { 23 unsigned long start = address; 24 int length = 1; 25 int nr; 26 struct page *page; 27 struct vm_area_struct *vma; 28 29 vma = find_vma(mm, addr); 30 if (!vma || !is_vm_hugetlb_page(vma)) 31 return ERR_PTR(-EINVAL); 32 33 pte = huge_pte_offset(mm, address); 34 35 /* hugetlb should be locked, and hence, prefaulted */ 36 WARN_ON(!pte || pte_none(*pte)); 37 38 page = &pte_page(*pte)[vpfn % (HPAGE_SIZE/PAGE_SIZE)]; 39 40 WARN_ON(!PageHead(page)); 41 42 return page; 43 } 44 45 int pmd_huge(pmd_t pmd) 46 { 47 return 0; 48 } 49 50 int pud_huge(pud_t pud) 51 { 52 return 0; 53 } 54 55 struct page * 56 follow_huge_pmd(struct mm_struct *mm, unsigned long address, 57 pmd_t *pmd, int write) 58 { 59 return NULL; 60 } 61 62 int pmd_huge_support(void) 63 { 64 return 0; 65 } 66 #else 67 68 struct page * 69 follow_huge_addr(struct mm_struct *mm, unsigned long address, int write) 70 { 71 return ERR_PTR(-EINVAL); 72 } 73 74 int pmd_huge(pmd_t pmd) 75 { 76 return !!(pmd_val(pmd) & _PAGE_PSE); 77 } 78 79 int pud_huge(pud_t pud) 80 { 81 return !!(pud_val(pud) & _PAGE_PSE); 82 } 83 84 int pmd_huge_support(void) 85 { 86 return 1; 87 } 88 #endif 89 90 #ifdef CONFIG_HUGETLB_PAGE 91 static unsigned long hugetlb_get_unmapped_area_bottomup(struct file *file, 92 unsigned long addr, unsigned long len, 93 unsigned long pgoff, unsigned long flags) 94 { 95 struct hstate *h = hstate_file(file); 96 struct vm_unmapped_area_info info; 97 98 info.flags = 0; 99 info.length = len; 100 info.low_limit = current->mm->mmap_legacy_base; 101 info.high_limit = TASK_SIZE; 102 info.align_mask = PAGE_MASK & ~huge_page_mask(h); 103 info.align_offset = 0; 104 return vm_unmapped_area(&info); 105 } 106 107 static unsigned long hugetlb_get_unmapped_area_topdown(struct file *file, 108 unsigned long addr0, unsigned long len, 109 unsigned long pgoff, unsigned long flags) 110 { 111 struct hstate *h = hstate_file(file); 112 struct vm_unmapped_area_info info; 113 unsigned long addr; 114 115 info.flags = VM_UNMAPPED_AREA_TOPDOWN; 116 info.length = len; 117 info.low_limit = PAGE_SIZE; 118 info.high_limit = current->mm->mmap_base; 119 info.align_mask = PAGE_MASK & ~huge_page_mask(h); 120 info.align_offset = 0; 121 addr = vm_unmapped_area(&info); 122 123 /* 124 * A failed mmap() very likely causes application failure, 125 * so fall back to the bottom-up function here. This scenario 126 * can happen with large stack limits and large mmap() 127 * allocations. 128 */ 129 if (addr & ~PAGE_MASK) { 130 VM_BUG_ON(addr != -ENOMEM); 131 info.flags = 0; 132 info.low_limit = TASK_UNMAPPED_BASE; 133 info.high_limit = TASK_SIZE; 134 addr = vm_unmapped_area(&info); 135 } 136 137 return addr; 138 } 139 140 unsigned long 141 hugetlb_get_unmapped_area(struct file *file, unsigned long addr, 142 unsigned long len, unsigned long pgoff, unsigned long flags) 143 { 144 struct hstate *h = hstate_file(file); 145 struct mm_struct *mm = current->mm; 146 struct vm_area_struct *vma; 147 148 if (len & ~huge_page_mask(h)) 149 return -EINVAL; 150 if (len > TASK_SIZE) 151 return -ENOMEM; 152 153 if (flags & MAP_FIXED) { 154 if (prepare_hugepage_range(file, addr, len)) 155 return -EINVAL; 156 return addr; 157 } 158 159 if (addr) { 160 addr = ALIGN(addr, huge_page_size(h)); 161 vma = find_vma(mm, addr); 162 if (TASK_SIZE - len >= addr && 163 (!vma || addr + len <= vma->vm_start)) 164 return addr; 165 } 166 if (mm->get_unmapped_area == arch_get_unmapped_area) 167 return hugetlb_get_unmapped_area_bottomup(file, addr, len, 168 pgoff, flags); 169 else 170 return hugetlb_get_unmapped_area_topdown(file, addr, len, 171 pgoff, flags); 172 } 173 #endif /* CONFIG_HUGETLB_PAGE */ 174 175 #ifdef CONFIG_X86_64 176 static __init int setup_hugepagesz(char *opt) 177 { 178 unsigned long ps = memparse(opt, &opt); 179 if (ps == PMD_SIZE) { 180 hugetlb_add_hstate(PMD_SHIFT - PAGE_SHIFT); 181 } else if (ps == PUD_SIZE && cpu_has_gbpages) { 182 hugetlb_add_hstate(PUD_SHIFT - PAGE_SHIFT); 183 } else { 184 printk(KERN_ERR "hugepagesz: Unsupported page size %lu M\n", 185 ps >> 20); 186 return 0; 187 } 188 return 1; 189 } 190 __setup("hugepagesz=", setup_hugepagesz); 191 #endif 192