1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * IBM System z Huge TLB Page Support for Kernel. 4 * 5 * Copyright IBM Corp. 2007,2020 6 * Author(s): Gerald Schaefer <gerald.schaefer@de.ibm.com> 7 */ 8 9 #define KMSG_COMPONENT "hugetlb" 10 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt 11 12 #include <asm/pgalloc.h> 13 #include <linux/mm.h> 14 #include <linux/hugetlb.h> 15 #include <linux/mman.h> 16 #include <linux/sched/mm.h> 17 #include <linux/security.h> 18 19 /* 20 * If the bit selected by single-bit bitmask "a" is set within "x", move 21 * it to the position indicated by single-bit bitmask "b". 22 */ 23 #define move_set_bit(x, a, b) (((x) & (a)) >> ilog2(a) << ilog2(b)) 24 25 static inline unsigned long __pte_to_rste(pte_t pte) 26 { 27 unsigned long rste; 28 29 /* 30 * Convert encoding pte bits pmd / pud bits 31 * lIR.uswrdy.p dy..R...I...wr 32 * empty 010.000000.0 -> 00..0...1...00 33 * prot-none, clean, old 111.000000.1 -> 00..1...1...00 34 * prot-none, clean, young 111.000001.1 -> 01..1...1...00 35 * prot-none, dirty, old 111.000010.1 -> 10..1...1...00 36 * prot-none, dirty, young 111.000011.1 -> 11..1...1...00 37 * read-only, clean, old 111.000100.1 -> 00..1...1...01 38 * read-only, clean, young 101.000101.1 -> 01..1...0...01 39 * read-only, dirty, old 111.000110.1 -> 10..1...1...01 40 * read-only, dirty, young 101.000111.1 -> 11..1...0...01 41 * read-write, clean, old 111.001100.1 -> 00..1...1...11 42 * read-write, clean, young 101.001101.1 -> 01..1...0...11 43 * read-write, dirty, old 110.001110.1 -> 10..0...1...11 44 * read-write, dirty, young 100.001111.1 -> 11..0...0...11 45 * HW-bits: R read-only, I invalid 46 * SW-bits: p present, y young, d dirty, r read, w write, s special, 47 * u unused, l large 48 */ 49 if (pte_present(pte)) { 50 rste = pte_val(pte) & PAGE_MASK; 51 rste |= move_set_bit(pte_val(pte), _PAGE_READ, 52 _SEGMENT_ENTRY_READ); 53 rste |= move_set_bit(pte_val(pte), _PAGE_WRITE, 54 _SEGMENT_ENTRY_WRITE); 55 rste |= move_set_bit(pte_val(pte), _PAGE_INVALID, 56 _SEGMENT_ENTRY_INVALID); 57 rste |= move_set_bit(pte_val(pte), _PAGE_PROTECT, 58 _SEGMENT_ENTRY_PROTECT); 59 rste |= move_set_bit(pte_val(pte), _PAGE_DIRTY, 60 _SEGMENT_ENTRY_DIRTY); 61 rste |= move_set_bit(pte_val(pte), _PAGE_YOUNG, 62 _SEGMENT_ENTRY_YOUNG); 63 #ifdef CONFIG_MEM_SOFT_DIRTY 64 rste |= move_set_bit(pte_val(pte), _PAGE_SOFT_DIRTY, 65 _SEGMENT_ENTRY_SOFT_DIRTY); 66 #endif 67 rste |= move_set_bit(pte_val(pte), _PAGE_NOEXEC, 68 _SEGMENT_ENTRY_NOEXEC); 69 } else 70 rste = _SEGMENT_ENTRY_EMPTY; 71 return rste; 72 } 73 74 static inline pte_t __rste_to_pte(unsigned long rste) 75 { 76 unsigned long pteval; 77 int present; 78 79 if ((rste & _REGION_ENTRY_TYPE_MASK) == _REGION_ENTRY_TYPE_R3) 80 present = pud_present(__pud(rste)); 81 else 82 present = pmd_present(__pmd(rste)); 83 84 /* 85 * Convert encoding pmd / pud bits pte bits 86 * dy..R...I...wr lIR.uswrdy.p 87 * empty 00..0...1...00 -> 010.000000.0 88 * prot-none, clean, old 00..1...1...00 -> 111.000000.1 89 * prot-none, clean, young 01..1...1...00 -> 111.000001.1 90 * prot-none, dirty, old 10..1...1...00 -> 111.000010.1 91 * prot-none, dirty, young 11..1...1...00 -> 111.000011.1 92 * read-only, clean, old 00..1...1...01 -> 111.000100.1 93 * read-only, clean, young 01..1...0...01 -> 101.000101.1 94 * read-only, dirty, old 10..1...1...01 -> 111.000110.1 95 * read-only, dirty, young 11..1...0...01 -> 101.000111.1 96 * read-write, clean, old 00..1...1...11 -> 111.001100.1 97 * read-write, clean, young 01..1...0...11 -> 101.001101.1 98 * read-write, dirty, old 10..0...1...11 -> 110.001110.1 99 * read-write, dirty, young 11..0...0...11 -> 100.001111.1 100 * HW-bits: R read-only, I invalid 101 * SW-bits: p present, y young, d dirty, r read, w write, s special, 102 * u unused, l large 103 */ 104 if (present) { 105 pteval = rste & _SEGMENT_ENTRY_ORIGIN_LARGE; 106 pteval |= _PAGE_LARGE | _PAGE_PRESENT; 107 pteval |= move_set_bit(rste, _SEGMENT_ENTRY_READ, _PAGE_READ); 108 pteval |= move_set_bit(rste, _SEGMENT_ENTRY_WRITE, _PAGE_WRITE); 109 pteval |= move_set_bit(rste, _SEGMENT_ENTRY_INVALID, _PAGE_INVALID); 110 pteval |= move_set_bit(rste, _SEGMENT_ENTRY_PROTECT, _PAGE_PROTECT); 111 pteval |= move_set_bit(rste, _SEGMENT_ENTRY_DIRTY, _PAGE_DIRTY); 112 pteval |= move_set_bit(rste, _SEGMENT_ENTRY_YOUNG, _PAGE_YOUNG); 113 #ifdef CONFIG_MEM_SOFT_DIRTY 114 pteval |= move_set_bit(rste, _SEGMENT_ENTRY_SOFT_DIRTY, _PAGE_SOFT_DIRTY); 115 #endif 116 pteval |= move_set_bit(rste, _SEGMENT_ENTRY_NOEXEC, _PAGE_NOEXEC); 117 } else 118 pteval = _PAGE_INVALID; 119 return __pte(pteval); 120 } 121 122 static void clear_huge_pte_skeys(struct mm_struct *mm, unsigned long rste) 123 { 124 struct page *page; 125 unsigned long size, paddr; 126 127 if (!mm_uses_skeys(mm) || 128 rste & _SEGMENT_ENTRY_INVALID) 129 return; 130 131 if ((rste & _REGION_ENTRY_TYPE_MASK) == _REGION_ENTRY_TYPE_R3) { 132 page = pud_page(__pud(rste)); 133 size = PUD_SIZE; 134 paddr = rste & PUD_MASK; 135 } else { 136 page = pmd_page(__pmd(rste)); 137 size = PMD_SIZE; 138 paddr = rste & PMD_MASK; 139 } 140 141 if (!test_and_set_bit(PG_arch_1, &page->flags)) 142 __storage_key_init_range(paddr, paddr + size - 1); 143 } 144 145 void set_huge_pte_at(struct mm_struct *mm, unsigned long addr, 146 pte_t *ptep, pte_t pte) 147 { 148 unsigned long rste; 149 150 rste = __pte_to_rste(pte); 151 if (!MACHINE_HAS_NX) 152 rste &= ~_SEGMENT_ENTRY_NOEXEC; 153 154 /* Set correct table type for 2G hugepages */ 155 if ((pte_val(*ptep) & _REGION_ENTRY_TYPE_MASK) == _REGION_ENTRY_TYPE_R3) { 156 if (likely(pte_present(pte))) 157 rste |= _REGION3_ENTRY_LARGE; 158 rste |= _REGION_ENTRY_TYPE_R3; 159 } else if (likely(pte_present(pte))) 160 rste |= _SEGMENT_ENTRY_LARGE; 161 162 clear_huge_pte_skeys(mm, rste); 163 set_pte(ptep, __pte(rste)); 164 } 165 166 pte_t huge_ptep_get(pte_t *ptep) 167 { 168 return __rste_to_pte(pte_val(*ptep)); 169 } 170 171 pte_t huge_ptep_get_and_clear(struct mm_struct *mm, 172 unsigned long addr, pte_t *ptep) 173 { 174 pte_t pte = huge_ptep_get(ptep); 175 pmd_t *pmdp = (pmd_t *) ptep; 176 pud_t *pudp = (pud_t *) ptep; 177 178 if ((pte_val(*ptep) & _REGION_ENTRY_TYPE_MASK) == _REGION_ENTRY_TYPE_R3) 179 pudp_xchg_direct(mm, addr, pudp, __pud(_REGION3_ENTRY_EMPTY)); 180 else 181 pmdp_xchg_direct(mm, addr, pmdp, __pmd(_SEGMENT_ENTRY_EMPTY)); 182 return pte; 183 } 184 185 pte_t *huge_pte_alloc(struct mm_struct *mm, struct vm_area_struct *vma, 186 unsigned long addr, unsigned long sz) 187 { 188 pgd_t *pgdp; 189 p4d_t *p4dp; 190 pud_t *pudp; 191 pmd_t *pmdp = NULL; 192 193 pgdp = pgd_offset(mm, addr); 194 p4dp = p4d_alloc(mm, pgdp, addr); 195 if (p4dp) { 196 pudp = pud_alloc(mm, p4dp, addr); 197 if (pudp) { 198 if (sz == PUD_SIZE) 199 return (pte_t *) pudp; 200 else if (sz == PMD_SIZE) 201 pmdp = pmd_alloc(mm, pudp, addr); 202 } 203 } 204 return (pte_t *) pmdp; 205 } 206 207 pte_t *huge_pte_offset(struct mm_struct *mm, 208 unsigned long addr, unsigned long sz) 209 { 210 pgd_t *pgdp; 211 p4d_t *p4dp; 212 pud_t *pudp; 213 pmd_t *pmdp = NULL; 214 215 pgdp = pgd_offset(mm, addr); 216 if (pgd_present(*pgdp)) { 217 p4dp = p4d_offset(pgdp, addr); 218 if (p4d_present(*p4dp)) { 219 pudp = pud_offset(p4dp, addr); 220 if (pud_present(*pudp)) { 221 if (pud_large(*pudp)) 222 return (pte_t *) pudp; 223 pmdp = pmd_offset(pudp, addr); 224 } 225 } 226 } 227 return (pte_t *) pmdp; 228 } 229 230 int pmd_huge(pmd_t pmd) 231 { 232 return pmd_large(pmd); 233 } 234 235 int pud_huge(pud_t pud) 236 { 237 return pud_large(pud); 238 } 239 240 bool __init arch_hugetlb_valid_size(unsigned long size) 241 { 242 if (MACHINE_HAS_EDAT1 && size == PMD_SIZE) 243 return true; 244 else if (MACHINE_HAS_EDAT2 && size == PUD_SIZE) 245 return true; 246 else 247 return false; 248 } 249 250 static unsigned long hugetlb_get_unmapped_area_bottomup(struct file *file, 251 unsigned long addr, unsigned long len, 252 unsigned long pgoff, unsigned long flags) 253 { 254 struct hstate *h = hstate_file(file); 255 struct vm_unmapped_area_info info; 256 257 info.flags = 0; 258 info.length = len; 259 info.low_limit = current->mm->mmap_base; 260 info.high_limit = TASK_SIZE; 261 info.align_mask = PAGE_MASK & ~huge_page_mask(h); 262 info.align_offset = 0; 263 return vm_unmapped_area(&info); 264 } 265 266 static unsigned long hugetlb_get_unmapped_area_topdown(struct file *file, 267 unsigned long addr0, unsigned long len, 268 unsigned long pgoff, unsigned long flags) 269 { 270 struct hstate *h = hstate_file(file); 271 struct vm_unmapped_area_info info; 272 unsigned long addr; 273 274 info.flags = VM_UNMAPPED_AREA_TOPDOWN; 275 info.length = len; 276 info.low_limit = PAGE_SIZE; 277 info.high_limit = current->mm->mmap_base; 278 info.align_mask = PAGE_MASK & ~huge_page_mask(h); 279 info.align_offset = 0; 280 addr = vm_unmapped_area(&info); 281 282 /* 283 * A failed mmap() very likely causes application failure, 284 * so fall back to the bottom-up function here. This scenario 285 * can happen with large stack limits and large mmap() 286 * allocations. 287 */ 288 if (addr & ~PAGE_MASK) { 289 VM_BUG_ON(addr != -ENOMEM); 290 info.flags = 0; 291 info.low_limit = TASK_UNMAPPED_BASE; 292 info.high_limit = TASK_SIZE; 293 addr = vm_unmapped_area(&info); 294 } 295 296 return addr; 297 } 298 299 unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr, 300 unsigned long len, unsigned long pgoff, unsigned long flags) 301 { 302 struct hstate *h = hstate_file(file); 303 struct mm_struct *mm = current->mm; 304 struct vm_area_struct *vma; 305 306 if (len & ~huge_page_mask(h)) 307 return -EINVAL; 308 if (len > TASK_SIZE - mmap_min_addr) 309 return -ENOMEM; 310 311 if (flags & MAP_FIXED) { 312 if (prepare_hugepage_range(file, addr, len)) 313 return -EINVAL; 314 goto check_asce_limit; 315 } 316 317 if (addr) { 318 addr = ALIGN(addr, huge_page_size(h)); 319 vma = find_vma(mm, addr); 320 if (TASK_SIZE - len >= addr && addr >= mmap_min_addr && 321 (!vma || addr + len <= vm_start_gap(vma))) 322 goto check_asce_limit; 323 } 324 325 if (mm->get_unmapped_area == arch_get_unmapped_area) 326 addr = hugetlb_get_unmapped_area_bottomup(file, addr, len, 327 pgoff, flags); 328 else 329 addr = hugetlb_get_unmapped_area_topdown(file, addr, len, 330 pgoff, flags); 331 if (offset_in_page(addr)) 332 return addr; 333 334 check_asce_limit: 335 return check_asce_limit(mm, addr, len); 336 } 337