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 void set_huge_pte_at(struct mm_struct *mm, unsigned long addr, 167 pte_t *ptep, pte_t pte, unsigned long sz) 168 { 169 __set_huge_pte_at(mm, addr, ptep, pte); 170 } 171 172 pte_t huge_ptep_get(pte_t *ptep) 173 { 174 return __rste_to_pte(pte_val(*ptep)); 175 } 176 177 pte_t huge_ptep_get_and_clear(struct mm_struct *mm, 178 unsigned long addr, pte_t *ptep) 179 { 180 pte_t pte = huge_ptep_get(ptep); 181 pmd_t *pmdp = (pmd_t *) ptep; 182 pud_t *pudp = (pud_t *) ptep; 183 184 if ((pte_val(*ptep) & _REGION_ENTRY_TYPE_MASK) == _REGION_ENTRY_TYPE_R3) 185 pudp_xchg_direct(mm, addr, pudp, __pud(_REGION3_ENTRY_EMPTY)); 186 else 187 pmdp_xchg_direct(mm, addr, pmdp, __pmd(_SEGMENT_ENTRY_EMPTY)); 188 return pte; 189 } 190 191 pte_t *huge_pte_alloc(struct mm_struct *mm, struct vm_area_struct *vma, 192 unsigned long addr, unsigned long sz) 193 { 194 pgd_t *pgdp; 195 p4d_t *p4dp; 196 pud_t *pudp; 197 pmd_t *pmdp = NULL; 198 199 pgdp = pgd_offset(mm, addr); 200 p4dp = p4d_alloc(mm, pgdp, addr); 201 if (p4dp) { 202 pudp = pud_alloc(mm, p4dp, addr); 203 if (pudp) { 204 if (sz == PUD_SIZE) 205 return (pte_t *) pudp; 206 else if (sz == PMD_SIZE) 207 pmdp = pmd_alloc(mm, pudp, addr); 208 } 209 } 210 return (pte_t *) pmdp; 211 } 212 213 pte_t *huge_pte_offset(struct mm_struct *mm, 214 unsigned long addr, unsigned long sz) 215 { 216 pgd_t *pgdp; 217 p4d_t *p4dp; 218 pud_t *pudp; 219 pmd_t *pmdp = NULL; 220 221 pgdp = pgd_offset(mm, addr); 222 if (pgd_present(*pgdp)) { 223 p4dp = p4d_offset(pgdp, addr); 224 if (p4d_present(*p4dp)) { 225 pudp = pud_offset(p4dp, addr); 226 if (pud_present(*pudp)) { 227 if (pud_leaf(*pudp)) 228 return (pte_t *) pudp; 229 pmdp = pmd_offset(pudp, addr); 230 } 231 } 232 } 233 return (pte_t *) pmdp; 234 } 235 236 int pmd_huge(pmd_t pmd) 237 { 238 return pmd_leaf(pmd); 239 } 240 241 int pud_huge(pud_t pud) 242 { 243 return pud_leaf(pud); 244 } 245 246 bool __init arch_hugetlb_valid_size(unsigned long size) 247 { 248 if (MACHINE_HAS_EDAT1 && size == PMD_SIZE) 249 return true; 250 else if (MACHINE_HAS_EDAT2 && size == PUD_SIZE) 251 return true; 252 else 253 return false; 254 } 255 256 static unsigned long hugetlb_get_unmapped_area_bottomup(struct file *file, 257 unsigned long addr, unsigned long len, 258 unsigned long pgoff, unsigned long flags) 259 { 260 struct hstate *h = hstate_file(file); 261 struct vm_unmapped_area_info info; 262 263 info.flags = 0; 264 info.length = len; 265 info.low_limit = current->mm->mmap_base; 266 info.high_limit = TASK_SIZE; 267 info.align_mask = PAGE_MASK & ~huge_page_mask(h); 268 info.align_offset = 0; 269 return vm_unmapped_area(&info); 270 } 271 272 static unsigned long hugetlb_get_unmapped_area_topdown(struct file *file, 273 unsigned long addr0, unsigned long len, 274 unsigned long pgoff, unsigned long flags) 275 { 276 struct hstate *h = hstate_file(file); 277 struct vm_unmapped_area_info info; 278 unsigned long addr; 279 280 info.flags = VM_UNMAPPED_AREA_TOPDOWN; 281 info.length = len; 282 info.low_limit = PAGE_SIZE; 283 info.high_limit = current->mm->mmap_base; 284 info.align_mask = PAGE_MASK & ~huge_page_mask(h); 285 info.align_offset = 0; 286 addr = vm_unmapped_area(&info); 287 288 /* 289 * A failed mmap() very likely causes application failure, 290 * so fall back to the bottom-up function here. This scenario 291 * can happen with large stack limits and large mmap() 292 * allocations. 293 */ 294 if (addr & ~PAGE_MASK) { 295 VM_BUG_ON(addr != -ENOMEM); 296 info.flags = 0; 297 info.low_limit = TASK_UNMAPPED_BASE; 298 info.high_limit = TASK_SIZE; 299 addr = vm_unmapped_area(&info); 300 } 301 302 return addr; 303 } 304 305 unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr, 306 unsigned long len, unsigned long pgoff, unsigned long flags) 307 { 308 struct hstate *h = hstate_file(file); 309 struct mm_struct *mm = current->mm; 310 struct vm_area_struct *vma; 311 312 if (len & ~huge_page_mask(h)) 313 return -EINVAL; 314 if (len > TASK_SIZE - mmap_min_addr) 315 return -ENOMEM; 316 317 if (flags & MAP_FIXED) { 318 if (prepare_hugepage_range(file, addr, len)) 319 return -EINVAL; 320 goto check_asce_limit; 321 } 322 323 if (addr) { 324 addr = ALIGN(addr, huge_page_size(h)); 325 vma = find_vma(mm, addr); 326 if (TASK_SIZE - len >= addr && addr >= mmap_min_addr && 327 (!vma || addr + len <= vm_start_gap(vma))) 328 goto check_asce_limit; 329 } 330 331 if (mm->get_unmapped_area == arch_get_unmapped_area) 332 addr = hugetlb_get_unmapped_area_bottomup(file, addr, len, 333 pgoff, flags); 334 else 335 addr = hugetlb_get_unmapped_area_topdown(file, addr, len, 336 pgoff, flags); 337 if (offset_in_page(addr)) 338 return addr; 339 340 check_asce_limit: 341 return check_asce_limit(mm, addr, len); 342 } 343