1 // SPDX-License-Identifier: GPL-2.0 2 #include <linux/sched/task.h> 3 #include <linux/pgtable.h> 4 #include <linux/kasan.h> 5 #include <asm/pgalloc.h> 6 #include <asm/facility.h> 7 #include <asm/sections.h> 8 #include <asm/physmem_info.h> 9 #include <asm/maccess.h> 10 #include <asm/abs_lowcore.h> 11 #include "decompressor.h" 12 #include "boot.h" 13 14 unsigned long __bootdata_preserved(s390_invalid_asce); 15 16 #ifdef CONFIG_PROC_FS 17 atomic_long_t __bootdata_preserved(direct_pages_count[PG_DIRECT_MAP_MAX]); 18 #endif 19 20 #define init_mm (*(struct mm_struct *)vmlinux.init_mm_off) 21 #define swapper_pg_dir vmlinux.swapper_pg_dir_off 22 #define invalid_pg_dir vmlinux.invalid_pg_dir_off 23 24 enum populate_mode { 25 POPULATE_NONE, 26 POPULATE_DIRECT, 27 POPULATE_ABS_LOWCORE, 28 #ifdef CONFIG_KASAN 29 POPULATE_KASAN_MAP_SHADOW, 30 POPULATE_KASAN_ZERO_SHADOW, 31 POPULATE_KASAN_SHALLOW 32 #endif 33 }; 34 35 static void pgtable_populate(unsigned long addr, unsigned long end, enum populate_mode mode); 36 37 #ifdef CONFIG_KASAN 38 39 #define kasan_early_shadow_page vmlinux.kasan_early_shadow_page_off 40 #define kasan_early_shadow_pte ((pte_t *)vmlinux.kasan_early_shadow_pte_off) 41 #define kasan_early_shadow_pmd ((pmd_t *)vmlinux.kasan_early_shadow_pmd_off) 42 #define kasan_early_shadow_pud ((pud_t *)vmlinux.kasan_early_shadow_pud_off) 43 #define kasan_early_shadow_p4d ((p4d_t *)vmlinux.kasan_early_shadow_p4d_off) 44 #define __sha(x) ((unsigned long)kasan_mem_to_shadow((void *)x)) 45 46 static pte_t pte_z; 47 48 static inline void kasan_populate(unsigned long start, unsigned long end, enum populate_mode mode) 49 { 50 start = PAGE_ALIGN_DOWN(__sha(start)); 51 end = PAGE_ALIGN(__sha(end)); 52 pgtable_populate(start, end, mode); 53 } 54 55 static void kasan_populate_shadow(void) 56 { 57 pmd_t pmd_z = __pmd(__pa(kasan_early_shadow_pte) | _SEGMENT_ENTRY); 58 pud_t pud_z = __pud(__pa(kasan_early_shadow_pmd) | _REGION3_ENTRY); 59 p4d_t p4d_z = __p4d(__pa(kasan_early_shadow_pud) | _REGION2_ENTRY); 60 unsigned long untracked_end; 61 unsigned long start, end; 62 int i; 63 64 pte_z = __pte(__pa(kasan_early_shadow_page) | pgprot_val(PAGE_KERNEL_RO)); 65 if (!machine.has_nx) 66 pte_z = clear_pte_bit(pte_z, __pgprot(_PAGE_NOEXEC)); 67 crst_table_init((unsigned long *)kasan_early_shadow_p4d, p4d_val(p4d_z)); 68 crst_table_init((unsigned long *)kasan_early_shadow_pud, pud_val(pud_z)); 69 crst_table_init((unsigned long *)kasan_early_shadow_pmd, pmd_val(pmd_z)); 70 memset64((u64 *)kasan_early_shadow_pte, pte_val(pte_z), PTRS_PER_PTE); 71 72 /* 73 * Current memory layout: 74 * +- 0 -------------+ +- shadow start -+ 75 * |1:1 ident mapping| /|1/8 of ident map| 76 * | | / | | 77 * +-end of ident map+ / +----------------+ 78 * | ... gap ... | / | kasan | 79 * | | / | zero page | 80 * +- vmalloc area -+ / | mapping | 81 * | vmalloc_size | / | (untracked) | 82 * +- modules vaddr -+ / +----------------+ 83 * | 2Gb |/ | unmapped | allocated per module 84 * +- shadow start -+ +----------------+ 85 * | 1/8 addr space | | zero pg mapping| (untracked) 86 * +- shadow end ----+---------+- shadow end ---+ 87 * 88 * Current memory layout (KASAN_VMALLOC): 89 * +- 0 -------------+ +- shadow start -+ 90 * |1:1 ident mapping| /|1/8 of ident map| 91 * | | / | | 92 * +-end of ident map+ / +----------------+ 93 * | ... gap ... | / | kasan zero page| (untracked) 94 * | | / | mapping | 95 * +- vmalloc area -+ / +----------------+ 96 * | vmalloc_size | / |shallow populate| 97 * +- modules vaddr -+ / +----------------+ 98 * | 2Gb |/ |shallow populate| 99 * +- shadow start -+ +----------------+ 100 * | 1/8 addr space | | zero pg mapping| (untracked) 101 * +- shadow end ----+---------+- shadow end ---+ 102 */ 103 104 for_each_physmem_usable_range(i, &start, &end) 105 kasan_populate(start, end, POPULATE_KASAN_MAP_SHADOW); 106 if (IS_ENABLED(CONFIG_KASAN_VMALLOC)) { 107 untracked_end = VMALLOC_START; 108 /* shallowly populate kasan shadow for vmalloc and modules */ 109 kasan_populate(VMALLOC_START, MODULES_END, POPULATE_KASAN_SHALLOW); 110 } else { 111 untracked_end = MODULES_VADDR; 112 } 113 /* populate kasan shadow for untracked memory */ 114 kasan_populate(ident_map_size, untracked_end, POPULATE_KASAN_ZERO_SHADOW); 115 kasan_populate(MODULES_END, _REGION1_SIZE, POPULATE_KASAN_ZERO_SHADOW); 116 } 117 118 static bool kasan_pgd_populate_zero_shadow(pgd_t *pgd, unsigned long addr, 119 unsigned long end, enum populate_mode mode) 120 { 121 if (mode == POPULATE_KASAN_ZERO_SHADOW && 122 IS_ALIGNED(addr, PGDIR_SIZE) && end - addr >= PGDIR_SIZE) { 123 pgd_populate(&init_mm, pgd, kasan_early_shadow_p4d); 124 return true; 125 } 126 return false; 127 } 128 129 static bool kasan_p4d_populate_zero_shadow(p4d_t *p4d, unsigned long addr, 130 unsigned long end, enum populate_mode mode) 131 { 132 if (mode == POPULATE_KASAN_ZERO_SHADOW && 133 IS_ALIGNED(addr, P4D_SIZE) && end - addr >= P4D_SIZE) { 134 p4d_populate(&init_mm, p4d, kasan_early_shadow_pud); 135 return true; 136 } 137 return false; 138 } 139 140 static bool kasan_pud_populate_zero_shadow(pud_t *pud, unsigned long addr, 141 unsigned long end, enum populate_mode mode) 142 { 143 if (mode == POPULATE_KASAN_ZERO_SHADOW && 144 IS_ALIGNED(addr, PUD_SIZE) && end - addr >= PUD_SIZE) { 145 pud_populate(&init_mm, pud, kasan_early_shadow_pmd); 146 return true; 147 } 148 return false; 149 } 150 151 static bool kasan_pmd_populate_zero_shadow(pmd_t *pmd, unsigned long addr, 152 unsigned long end, enum populate_mode mode) 153 { 154 if (mode == POPULATE_KASAN_ZERO_SHADOW && 155 IS_ALIGNED(addr, PMD_SIZE) && end - addr >= PMD_SIZE) { 156 pmd_populate(&init_mm, pmd, kasan_early_shadow_pte); 157 return true; 158 } 159 return false; 160 } 161 162 static bool kasan_pte_populate_zero_shadow(pte_t *pte, enum populate_mode mode) 163 { 164 pte_t entry; 165 166 if (mode == POPULATE_KASAN_ZERO_SHADOW) { 167 set_pte(pte, pte_z); 168 return true; 169 } 170 return false; 171 } 172 #else 173 174 static inline void kasan_populate_shadow(void) {} 175 176 static inline bool kasan_pgd_populate_zero_shadow(pgd_t *pgd, unsigned long addr, 177 unsigned long end, enum populate_mode mode) 178 { 179 return false; 180 } 181 182 static inline bool kasan_p4d_populate_zero_shadow(p4d_t *p4d, unsigned long addr, 183 unsigned long end, enum populate_mode mode) 184 { 185 return false; 186 } 187 188 static inline bool kasan_pud_populate_zero_shadow(pud_t *pud, unsigned long addr, 189 unsigned long end, enum populate_mode mode) 190 { 191 return false; 192 } 193 194 static inline bool kasan_pmd_populate_zero_shadow(pmd_t *pmd, unsigned long addr, 195 unsigned long end, enum populate_mode mode) 196 { 197 return false; 198 } 199 200 static bool kasan_pte_populate_zero_shadow(pte_t *pte, enum populate_mode mode) 201 { 202 return false; 203 } 204 205 #endif 206 207 /* 208 * Mimic virt_to_kpte() in lack of init_mm symbol. Skip pmd NULL check though. 209 */ 210 static inline pte_t *__virt_to_kpte(unsigned long va) 211 { 212 return pte_offset_kernel(pmd_offset(pud_offset(p4d_offset(pgd_offset_k(va), va), va), va), va); 213 } 214 215 static void *boot_crst_alloc(unsigned long val) 216 { 217 unsigned long size = PAGE_SIZE << CRST_ALLOC_ORDER; 218 unsigned long *table; 219 220 table = (unsigned long *)physmem_alloc_top_down(RR_VMEM, size, size); 221 crst_table_init(table, val); 222 return table; 223 } 224 225 static pte_t *boot_pte_alloc(void) 226 { 227 static void *pte_leftover; 228 pte_t *pte; 229 230 /* 231 * handling pte_leftovers this way helps to avoid memory fragmentation 232 * during POPULATE_KASAN_MAP_SHADOW when EDAT is off 233 */ 234 if (!pte_leftover) { 235 pte_leftover = (void *)physmem_alloc_top_down(RR_VMEM, PAGE_SIZE, PAGE_SIZE); 236 pte = pte_leftover + _PAGE_TABLE_SIZE; 237 } else { 238 pte = pte_leftover; 239 pte_leftover = NULL; 240 } 241 242 memset64((u64 *)pte, _PAGE_INVALID, PTRS_PER_PTE); 243 return pte; 244 } 245 246 static unsigned long _pa(unsigned long addr, unsigned long size, enum populate_mode mode) 247 { 248 switch (mode) { 249 case POPULATE_NONE: 250 return -1; 251 case POPULATE_DIRECT: 252 return addr; 253 case POPULATE_ABS_LOWCORE: 254 return __abs_lowcore_pa(addr); 255 #ifdef CONFIG_KASAN 256 case POPULATE_KASAN_MAP_SHADOW: 257 addr = physmem_alloc_top_down(RR_VMEM, size, size); 258 memset((void *)addr, 0, size); 259 return addr; 260 #endif 261 default: 262 return -1; 263 } 264 } 265 266 static bool can_large_pud(pud_t *pu_dir, unsigned long addr, unsigned long end) 267 { 268 return machine.has_edat2 && 269 IS_ALIGNED(addr, PUD_SIZE) && (end - addr) >= PUD_SIZE; 270 } 271 272 static bool can_large_pmd(pmd_t *pm_dir, unsigned long addr, unsigned long end) 273 { 274 return machine.has_edat1 && 275 IS_ALIGNED(addr, PMD_SIZE) && (end - addr) >= PMD_SIZE; 276 } 277 278 static void pgtable_pte_populate(pmd_t *pmd, unsigned long addr, unsigned long end, 279 enum populate_mode mode) 280 { 281 unsigned long pages = 0; 282 pte_t *pte, entry; 283 284 pte = pte_offset_kernel(pmd, addr); 285 for (; addr < end; addr += PAGE_SIZE, pte++) { 286 if (pte_none(*pte)) { 287 if (kasan_pte_populate_zero_shadow(pte, mode)) 288 continue; 289 entry = __pte(_pa(addr, PAGE_SIZE, mode)); 290 entry = set_pte_bit(entry, PAGE_KERNEL_EXEC); 291 set_pte(pte, entry); 292 pages++; 293 } 294 } 295 if (mode == POPULATE_DIRECT) 296 update_page_count(PG_DIRECT_MAP_4K, pages); 297 } 298 299 static void pgtable_pmd_populate(pud_t *pud, unsigned long addr, unsigned long end, 300 enum populate_mode mode) 301 { 302 unsigned long next, pages = 0; 303 pmd_t *pmd, entry; 304 pte_t *pte; 305 306 pmd = pmd_offset(pud, addr); 307 for (; addr < end; addr = next, pmd++) { 308 next = pmd_addr_end(addr, end); 309 if (pmd_none(*pmd)) { 310 if (kasan_pmd_populate_zero_shadow(pmd, addr, next, mode)) 311 continue; 312 if (can_large_pmd(pmd, addr, next)) { 313 entry = __pmd(_pa(addr, _SEGMENT_SIZE, mode)); 314 entry = set_pmd_bit(entry, SEGMENT_KERNEL_EXEC); 315 set_pmd(pmd, entry); 316 pages++; 317 continue; 318 } 319 pte = boot_pte_alloc(); 320 pmd_populate(&init_mm, pmd, pte); 321 } else if (pmd_large(*pmd)) { 322 continue; 323 } 324 pgtable_pte_populate(pmd, addr, next, mode); 325 } 326 if (mode == POPULATE_DIRECT) 327 update_page_count(PG_DIRECT_MAP_1M, pages); 328 } 329 330 static void pgtable_pud_populate(p4d_t *p4d, unsigned long addr, unsigned long end, 331 enum populate_mode mode) 332 { 333 unsigned long next, pages = 0; 334 pud_t *pud, entry; 335 pmd_t *pmd; 336 337 pud = pud_offset(p4d, addr); 338 for (; addr < end; addr = next, pud++) { 339 next = pud_addr_end(addr, end); 340 if (pud_none(*pud)) { 341 if (kasan_pud_populate_zero_shadow(pud, addr, next, mode)) 342 continue; 343 if (can_large_pud(pud, addr, next)) { 344 entry = __pud(_pa(addr, _REGION3_SIZE, mode)); 345 entry = set_pud_bit(entry, REGION3_KERNEL_EXEC); 346 set_pud(pud, entry); 347 pages++; 348 continue; 349 } 350 pmd = boot_crst_alloc(_SEGMENT_ENTRY_EMPTY); 351 pud_populate(&init_mm, pud, pmd); 352 } else if (pud_large(*pud)) { 353 continue; 354 } 355 pgtable_pmd_populate(pud, addr, next, mode); 356 } 357 if (mode == POPULATE_DIRECT) 358 update_page_count(PG_DIRECT_MAP_2G, pages); 359 } 360 361 static void pgtable_p4d_populate(pgd_t *pgd, unsigned long addr, unsigned long end, 362 enum populate_mode mode) 363 { 364 unsigned long next; 365 p4d_t *p4d; 366 pud_t *pud; 367 368 p4d = p4d_offset(pgd, addr); 369 for (; addr < end; addr = next, p4d++) { 370 next = p4d_addr_end(addr, end); 371 if (p4d_none(*p4d)) { 372 if (kasan_p4d_populate_zero_shadow(p4d, addr, next, mode)) 373 continue; 374 pud = boot_crst_alloc(_REGION3_ENTRY_EMPTY); 375 p4d_populate(&init_mm, p4d, pud); 376 } 377 pgtable_pud_populate(p4d, addr, next, mode); 378 } 379 } 380 381 static void pgtable_populate(unsigned long addr, unsigned long end, enum populate_mode mode) 382 { 383 unsigned long next; 384 pgd_t *pgd; 385 p4d_t *p4d; 386 387 pgd = pgd_offset(&init_mm, addr); 388 for (; addr < end; addr = next, pgd++) { 389 next = pgd_addr_end(addr, end); 390 if (pgd_none(*pgd)) { 391 if (kasan_pgd_populate_zero_shadow(pgd, addr, next, mode)) 392 continue; 393 p4d = boot_crst_alloc(_REGION2_ENTRY_EMPTY); 394 pgd_populate(&init_mm, pgd, p4d); 395 } 396 #ifdef CONFIG_KASAN 397 if (mode == POPULATE_KASAN_SHALLOW) 398 continue; 399 #endif 400 pgtable_p4d_populate(pgd, addr, next, mode); 401 } 402 } 403 404 void setup_vmem(unsigned long asce_limit) 405 { 406 unsigned long start, end; 407 unsigned long asce_type; 408 unsigned long asce_bits; 409 int i; 410 411 if (asce_limit == _REGION1_SIZE) { 412 asce_type = _REGION2_ENTRY_EMPTY; 413 asce_bits = _ASCE_TYPE_REGION2 | _ASCE_TABLE_LENGTH; 414 } else { 415 asce_type = _REGION3_ENTRY_EMPTY; 416 asce_bits = _ASCE_TYPE_REGION3 | _ASCE_TABLE_LENGTH; 417 } 418 s390_invalid_asce = invalid_pg_dir | _ASCE_TYPE_REGION3 | _ASCE_TABLE_LENGTH; 419 420 crst_table_init((unsigned long *)swapper_pg_dir, asce_type); 421 crst_table_init((unsigned long *)invalid_pg_dir, _REGION3_ENTRY_EMPTY); 422 423 /* 424 * To allow prefixing the lowcore must be mapped with 4KB pages. 425 * To prevent creation of a large page at address 0 first map 426 * the lowcore and create the identity mapping only afterwards. 427 */ 428 pgtable_populate(0, sizeof(struct lowcore), POPULATE_DIRECT); 429 for_each_physmem_usable_range(i, &start, &end) 430 pgtable_populate(start, end, POPULATE_DIRECT); 431 pgtable_populate(__abs_lowcore, __abs_lowcore + sizeof(struct lowcore), 432 POPULATE_ABS_LOWCORE); 433 pgtable_populate(__memcpy_real_area, __memcpy_real_area + PAGE_SIZE, 434 POPULATE_NONE); 435 memcpy_real_ptep = __virt_to_kpte(__memcpy_real_area); 436 437 kasan_populate_shadow(); 438 439 S390_lowcore.kernel_asce = swapper_pg_dir | asce_bits; 440 S390_lowcore.user_asce = s390_invalid_asce; 441 442 __ctl_load(S390_lowcore.kernel_asce, 1, 1); 443 __ctl_load(S390_lowcore.user_asce, 7, 7); 444 __ctl_load(S390_lowcore.kernel_asce, 13, 13); 445 446 init_mm.context.asce = S390_lowcore.kernel_asce; 447 } 448