1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * IA-64 Huge TLB Page Support for Kernel. 4 * 5 * Copyright (C) 2002-2004 Rohit Seth <rohit.seth@intel.com> 6 * Copyright (C) 2003-2004 Ken Chen <kenneth.w.chen@intel.com> 7 * 8 * Sep, 2003: add numa support 9 * Feb, 2004: dynamic hugetlb page size via boot parameter 10 */ 11 12 #include <linux/init.h> 13 #include <linux/fs.h> 14 #include <linux/mm.h> 15 #include <linux/hugetlb.h> 16 #include <linux/pagemap.h> 17 #include <linux/module.h> 18 #include <linux/sysctl.h> 19 #include <linux/log2.h> 20 #include <asm/mman.h> 21 #include <asm/tlb.h> 22 #include <asm/tlbflush.h> 23 24 unsigned int hpage_shift = HPAGE_SHIFT_DEFAULT; 25 EXPORT_SYMBOL(hpage_shift); 26 27 pte_t * 28 huge_pte_alloc(struct mm_struct *mm, unsigned long addr, unsigned long sz) 29 { 30 unsigned long taddr = htlbpage_to_page(addr); 31 pgd_t *pgd; 32 p4d_t *p4d; 33 pud_t *pud; 34 pmd_t *pmd; 35 pte_t *pte = NULL; 36 37 pgd = pgd_offset(mm, taddr); 38 p4d = p4d_offset(pgd, taddr); 39 pud = pud_alloc(mm, p4d, taddr); 40 if (pud) { 41 pmd = pmd_alloc(mm, pud, taddr); 42 if (pmd) 43 pte = pte_alloc_map(mm, pmd, taddr); 44 } 45 return pte; 46 } 47 48 pte_t * 49 huge_pte_offset (struct mm_struct *mm, unsigned long addr, unsigned long sz) 50 { 51 unsigned long taddr = htlbpage_to_page(addr); 52 pgd_t *pgd; 53 p4d_t *p4d; 54 pud_t *pud; 55 pmd_t *pmd; 56 pte_t *pte = NULL; 57 58 pgd = pgd_offset(mm, taddr); 59 if (pgd_present(*pgd)) { 60 p4d = p4d_offset(pgd, addr); 61 if (p4d_present(*p4d)) { 62 pud = pud_offset(p4d, taddr); 63 if (pud_present(*pud)) { 64 pmd = pmd_offset(pud, taddr); 65 if (pmd_present(*pmd)) 66 pte = pte_offset_map(pmd, taddr); 67 } 68 } 69 } 70 71 return pte; 72 } 73 74 #define mk_pte_huge(entry) { pte_val(entry) |= _PAGE_P; } 75 76 /* 77 * Don't actually need to do any preparation, but need to make sure 78 * the address is in the right region. 79 */ 80 int prepare_hugepage_range(struct file *file, 81 unsigned long addr, unsigned long len) 82 { 83 if (len & ~HPAGE_MASK) 84 return -EINVAL; 85 if (addr & ~HPAGE_MASK) 86 return -EINVAL; 87 if (REGION_NUMBER(addr) != RGN_HPAGE) 88 return -EINVAL; 89 90 return 0; 91 } 92 93 struct page *follow_huge_addr(struct mm_struct *mm, unsigned long addr, int write) 94 { 95 struct page *page; 96 pte_t *ptep; 97 98 if (REGION_NUMBER(addr) != RGN_HPAGE) 99 return ERR_PTR(-EINVAL); 100 101 ptep = huge_pte_offset(mm, addr, HPAGE_SIZE); 102 if (!ptep || pte_none(*ptep)) 103 return NULL; 104 page = pte_page(*ptep); 105 page += ((addr & ~HPAGE_MASK) >> PAGE_SHIFT); 106 return page; 107 } 108 int pmd_huge(pmd_t pmd) 109 { 110 return 0; 111 } 112 113 int pud_huge(pud_t pud) 114 { 115 return 0; 116 } 117 118 void hugetlb_free_pgd_range(struct mmu_gather *tlb, 119 unsigned long addr, unsigned long end, 120 unsigned long floor, unsigned long ceiling) 121 { 122 /* 123 * This is called to free hugetlb page tables. 124 * 125 * The offset of these addresses from the base of the hugetlb 126 * region must be scaled down by HPAGE_SIZE/PAGE_SIZE so that 127 * the standard free_pgd_range will free the right page tables. 128 * 129 * If floor and ceiling are also in the hugetlb region, they 130 * must likewise be scaled down; but if outside, left unchanged. 131 */ 132 133 addr = htlbpage_to_page(addr); 134 end = htlbpage_to_page(end); 135 if (REGION_NUMBER(floor) == RGN_HPAGE) 136 floor = htlbpage_to_page(floor); 137 if (REGION_NUMBER(ceiling) == RGN_HPAGE) 138 ceiling = htlbpage_to_page(ceiling); 139 140 free_pgd_range(tlb, addr, end, floor, ceiling); 141 } 142 143 unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr, unsigned long len, 144 unsigned long pgoff, unsigned long flags) 145 { 146 struct vm_unmapped_area_info info; 147 148 if (len > RGN_MAP_LIMIT) 149 return -ENOMEM; 150 if (len & ~HPAGE_MASK) 151 return -EINVAL; 152 153 /* Handle MAP_FIXED */ 154 if (flags & MAP_FIXED) { 155 if (prepare_hugepage_range(file, addr, len)) 156 return -EINVAL; 157 return addr; 158 } 159 160 /* This code assumes that RGN_HPAGE != 0. */ 161 if ((REGION_NUMBER(addr) != RGN_HPAGE) || (addr & (HPAGE_SIZE - 1))) 162 addr = HPAGE_REGION_BASE; 163 164 info.flags = 0; 165 info.length = len; 166 info.low_limit = addr; 167 info.high_limit = HPAGE_REGION_BASE + RGN_MAP_LIMIT; 168 info.align_mask = PAGE_MASK & (HPAGE_SIZE - 1); 169 info.align_offset = 0; 170 return vm_unmapped_area(&info); 171 } 172 173 static int __init hugetlb_setup_sz(char *str) 174 { 175 u64 tr_pages; 176 unsigned long long size; 177 178 if (ia64_pal_vm_page_size(&tr_pages, NULL) != 0) 179 /* 180 * shouldn't happen, but just in case. 181 */ 182 tr_pages = 0x15557000UL; 183 184 size = memparse(str, &str); 185 if (*str || !is_power_of_2(size) || !(tr_pages & size) || 186 size <= PAGE_SIZE || 187 size >= (1UL << PAGE_SHIFT << MAX_ORDER)) { 188 printk(KERN_WARNING "Invalid huge page size specified\n"); 189 return 1; 190 } 191 192 hpage_shift = __ffs(size); 193 /* 194 * boot cpu already executed ia64_mmu_init, and has HPAGE_SHIFT_DEFAULT 195 * override here with new page shift. 196 */ 197 ia64_set_rr(HPAGE_REGION_BASE, hpage_shift << 2); 198 return 0; 199 } 200 early_param("hugepagesz", hugetlb_setup_sz); 201