1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Page table allocation functions 4 * 5 * Copyright IBM Corp. 2016 6 * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com> 7 */ 8 9 #include <linux/sysctl.h> 10 #include <linux/slab.h> 11 #include <linux/mm.h> 12 #include <asm/mmu_context.h> 13 #include <asm/page-states.h> 14 #include <asm/pgalloc.h> 15 #include <asm/tlbflush.h> 16 17 unsigned long *crst_table_alloc_noprof(struct mm_struct *mm) 18 { 19 gfp_t gfp = GFP_KERNEL_ACCOUNT; 20 struct ptdesc *ptdesc; 21 unsigned long *table; 22 23 if (mm == &init_mm) 24 gfp &= ~__GFP_ACCOUNT; 25 ptdesc = pagetable_alloc_noprof(gfp, CRST_ALLOC_ORDER); 26 if (!ptdesc) 27 return NULL; 28 table = ptdesc_address(ptdesc); 29 __arch_set_page_dat(table, 1UL << CRST_ALLOC_ORDER); 30 return table; 31 } 32 33 void crst_table_free(struct mm_struct *mm, unsigned long *table) 34 { 35 if (!table) 36 return; 37 pagetable_free(virt_to_ptdesc(table)); 38 } 39 40 static void __crst_table_upgrade(void *arg) 41 { 42 struct mm_struct *mm = arg; 43 struct ctlreg asce; 44 45 /* change all active ASCEs to avoid the creation of new TLBs */ 46 if (current->active_mm == mm) { 47 asce.val = mm->context.asce; 48 get_lowcore()->user_asce = asce; 49 local_ctl_load(7, &asce); 50 if (!test_thread_flag(TIF_ASCE_PRIMARY)) 51 local_ctl_load(1, &asce); 52 } 53 __tlb_flush_local(); 54 } 55 56 int crst_table_upgrade(struct mm_struct *mm, unsigned long end) 57 { 58 unsigned long *pgd = NULL, *p4d = NULL, *__pgd; 59 unsigned long asce_limit = mm->context.asce_limit; 60 61 mmap_assert_write_locked(mm); 62 63 /* upgrade should only happen from 3 to 4, 3 to 5, or 4 to 5 levels */ 64 VM_BUG_ON(asce_limit < _REGION2_SIZE); 65 66 if (end <= asce_limit) 67 return 0; 68 69 if (asce_limit == _REGION2_SIZE) { 70 p4d = crst_table_alloc(mm); 71 if (unlikely(!p4d)) 72 goto err_p4d; 73 crst_table_init(p4d, _REGION2_ENTRY_EMPTY); 74 pagetable_p4d_ctor(virt_to_ptdesc(p4d)); 75 } 76 if (end > _REGION1_SIZE) { 77 pgd = crst_table_alloc(mm); 78 if (unlikely(!pgd)) 79 goto err_pgd; 80 crst_table_init(pgd, _REGION1_ENTRY_EMPTY); 81 pagetable_pgd_ctor(virt_to_ptdesc(pgd)); 82 } 83 84 spin_lock_bh(&mm->page_table_lock); 85 86 if (p4d) { 87 __pgd = (unsigned long *) mm->pgd; 88 p4d_populate(mm, (p4d_t *) p4d, (pud_t *) __pgd); 89 mm->pgd = (pgd_t *) p4d; 90 mm->context.asce_limit = _REGION1_SIZE; 91 mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH | 92 _ASCE_USER_BITS | _ASCE_TYPE_REGION2; 93 mm_inc_nr_puds(mm); 94 } 95 if (pgd) { 96 __pgd = (unsigned long *) mm->pgd; 97 pgd_populate(mm, (pgd_t *) pgd, (p4d_t *) __pgd); 98 mm->pgd = (pgd_t *) pgd; 99 mm->context.asce_limit = TASK_SIZE_MAX; 100 mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH | 101 _ASCE_USER_BITS | _ASCE_TYPE_REGION1; 102 } 103 104 spin_unlock_bh(&mm->page_table_lock); 105 106 on_each_cpu(__crst_table_upgrade, mm, 0); 107 108 return 0; 109 110 err_pgd: 111 pagetable_dtor(virt_to_ptdesc(p4d)); 112 crst_table_free(mm, p4d); 113 err_p4d: 114 return -ENOMEM; 115 } 116 117 #ifdef CONFIG_PGSTE 118 119 struct ptdesc *page_table_alloc_pgste_noprof(struct mm_struct *mm) 120 { 121 struct ptdesc *ptdesc; 122 u64 *table; 123 124 ptdesc = pagetable_alloc_noprof(GFP_KERNEL_ACCOUNT, 0); 125 if (ptdesc) { 126 table = (u64 *)ptdesc_address(ptdesc); 127 __arch_set_page_dat(table, 1); 128 memset64(table, _PAGE_INVALID, PTRS_PER_PTE); 129 memset64(table + PTRS_PER_PTE, 0, PTRS_PER_PTE); 130 } 131 return ptdesc; 132 } 133 134 void page_table_free_pgste(struct ptdesc *ptdesc) 135 { 136 pagetable_free(ptdesc); 137 } 138 139 #endif /* CONFIG_PGSTE */ 140 141 unsigned long *page_table_alloc_noprof(struct mm_struct *mm) 142 { 143 gfp_t gfp = GFP_KERNEL_ACCOUNT; 144 struct ptdesc *ptdesc; 145 unsigned long *table; 146 147 if (mm == &init_mm) 148 gfp &= ~__GFP_ACCOUNT; 149 ptdesc = pagetable_alloc_noprof(gfp, 0); 150 if (!ptdesc) 151 return NULL; 152 if (!pagetable_pte_ctor(mm, ptdesc)) { 153 pagetable_free(ptdesc); 154 return NULL; 155 } 156 table = ptdesc_address(ptdesc); 157 __arch_set_page_dat(table, 1); 158 memset64((u64 *)table, _PAGE_INVALID, PTRS_PER_PTE); 159 memset64((u64 *)table + PTRS_PER_PTE, 0, PTRS_PER_PTE); 160 return table; 161 } 162 163 void page_table_free(struct mm_struct *mm, unsigned long *table) 164 { 165 struct ptdesc *ptdesc = virt_to_ptdesc(table); 166 167 if (pagetable_is_reserved(ptdesc)) 168 return free_reserved_ptdesc(ptdesc); 169 pagetable_dtor_free(ptdesc); 170 } 171 172 #ifdef CONFIG_TRANSPARENT_HUGEPAGE 173 static void pte_free_now(struct rcu_head *head) 174 { 175 struct ptdesc *ptdesc = container_of(head, struct ptdesc, pt_rcu_head); 176 177 pagetable_dtor_free(ptdesc); 178 } 179 180 void pte_free_defer(struct mm_struct *mm, pgtable_t pgtable) 181 { 182 struct ptdesc *ptdesc = virt_to_ptdesc(pgtable); 183 184 call_rcu(&ptdesc->pt_rcu_head, pte_free_now); 185 } 186 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ 187 188 /* 189 * Base infrastructure required to generate basic asces, region, segment, 190 * and page tables that do not make use of enhanced features like EDAT1. 191 */ 192 193 static struct kmem_cache *base_pgt_cache; 194 195 static unsigned long *base_pgt_alloc(void) 196 { 197 unsigned long *table; 198 199 table = kmem_cache_alloc(base_pgt_cache, GFP_KERNEL); 200 if (table) 201 memset64((u64 *)table, _PAGE_INVALID, PTRS_PER_PTE); 202 return table; 203 } 204 205 static void base_pgt_free(unsigned long *table) 206 { 207 kmem_cache_free(base_pgt_cache, table); 208 } 209 210 static unsigned long *base_crst_alloc(unsigned long val) 211 { 212 unsigned long *table; 213 struct ptdesc *ptdesc; 214 215 ptdesc = pagetable_alloc(GFP_KERNEL, CRST_ALLOC_ORDER); 216 if (!ptdesc) 217 return NULL; 218 table = ptdesc_address(ptdesc); 219 crst_table_init(table, val); 220 return table; 221 } 222 223 static void base_crst_free(unsigned long *table) 224 { 225 if (!table) 226 return; 227 pagetable_free(virt_to_ptdesc(table)); 228 } 229 230 #define BASE_ADDR_END_FUNC(NAME, SIZE) \ 231 static inline unsigned long base_##NAME##_addr_end(unsigned long addr, \ 232 unsigned long end) \ 233 { \ 234 unsigned long next = (addr + (SIZE)) & ~((SIZE) - 1); \ 235 \ 236 return (next - 1) < (end - 1) ? next : end; \ 237 } 238 239 BASE_ADDR_END_FUNC(page, PAGE_SIZE) 240 BASE_ADDR_END_FUNC(segment, _SEGMENT_SIZE) 241 BASE_ADDR_END_FUNC(region3, _REGION3_SIZE) 242 BASE_ADDR_END_FUNC(region2, _REGION2_SIZE) 243 BASE_ADDR_END_FUNC(region1, _REGION1_SIZE) 244 245 static inline unsigned long base_lra(unsigned long address) 246 { 247 unsigned long real; 248 249 asm volatile( 250 " lra %0,0(%1)" 251 : "=d" (real) : "a" (address) : "cc"); 252 return real; 253 } 254 255 static int base_page_walk(unsigned long *origin, unsigned long addr, 256 unsigned long end, int alloc) 257 { 258 unsigned long *pte, next; 259 260 if (!alloc) 261 return 0; 262 pte = origin; 263 pte += (addr & _PAGE_INDEX) >> PAGE_SHIFT; 264 do { 265 next = base_page_addr_end(addr, end); 266 *pte = base_lra(addr); 267 } while (pte++, addr = next, addr < end); 268 return 0; 269 } 270 271 static int base_segment_walk(unsigned long *origin, unsigned long addr, 272 unsigned long end, int alloc) 273 { 274 unsigned long *ste, next, *table; 275 int rc; 276 277 ste = origin; 278 ste += (addr & _SEGMENT_INDEX) >> _SEGMENT_SHIFT; 279 do { 280 next = base_segment_addr_end(addr, end); 281 if (*ste & _SEGMENT_ENTRY_INVALID) { 282 if (!alloc) 283 continue; 284 table = base_pgt_alloc(); 285 if (!table) 286 return -ENOMEM; 287 *ste = __pa(table) | _SEGMENT_ENTRY; 288 } 289 table = __va(*ste & _SEGMENT_ENTRY_ORIGIN); 290 rc = base_page_walk(table, addr, next, alloc); 291 if (rc) 292 return rc; 293 if (!alloc) 294 base_pgt_free(table); 295 cond_resched(); 296 } while (ste++, addr = next, addr < end); 297 return 0; 298 } 299 300 static int base_region3_walk(unsigned long *origin, unsigned long addr, 301 unsigned long end, int alloc) 302 { 303 unsigned long *rtte, next, *table; 304 int rc; 305 306 rtte = origin; 307 rtte += (addr & _REGION3_INDEX) >> _REGION3_SHIFT; 308 do { 309 next = base_region3_addr_end(addr, end); 310 if (*rtte & _REGION_ENTRY_INVALID) { 311 if (!alloc) 312 continue; 313 table = base_crst_alloc(_SEGMENT_ENTRY_EMPTY); 314 if (!table) 315 return -ENOMEM; 316 *rtte = __pa(table) | _REGION3_ENTRY; 317 } 318 table = __va(*rtte & _REGION_ENTRY_ORIGIN); 319 rc = base_segment_walk(table, addr, next, alloc); 320 if (rc) 321 return rc; 322 if (!alloc) 323 base_crst_free(table); 324 } while (rtte++, addr = next, addr < end); 325 return 0; 326 } 327 328 static int base_region2_walk(unsigned long *origin, unsigned long addr, 329 unsigned long end, int alloc) 330 { 331 unsigned long *rste, next, *table; 332 int rc; 333 334 rste = origin; 335 rste += (addr & _REGION2_INDEX) >> _REGION2_SHIFT; 336 do { 337 next = base_region2_addr_end(addr, end); 338 if (*rste & _REGION_ENTRY_INVALID) { 339 if (!alloc) 340 continue; 341 table = base_crst_alloc(_REGION3_ENTRY_EMPTY); 342 if (!table) 343 return -ENOMEM; 344 *rste = __pa(table) | _REGION2_ENTRY; 345 } 346 table = __va(*rste & _REGION_ENTRY_ORIGIN); 347 rc = base_region3_walk(table, addr, next, alloc); 348 if (rc) 349 return rc; 350 if (!alloc) 351 base_crst_free(table); 352 } while (rste++, addr = next, addr < end); 353 return 0; 354 } 355 356 static int base_region1_walk(unsigned long *origin, unsigned long addr, 357 unsigned long end, int alloc) 358 { 359 unsigned long *rfte, next, *table; 360 int rc; 361 362 rfte = origin; 363 rfte += (addr & _REGION1_INDEX) >> _REGION1_SHIFT; 364 do { 365 next = base_region1_addr_end(addr, end); 366 if (*rfte & _REGION_ENTRY_INVALID) { 367 if (!alloc) 368 continue; 369 table = base_crst_alloc(_REGION2_ENTRY_EMPTY); 370 if (!table) 371 return -ENOMEM; 372 *rfte = __pa(table) | _REGION1_ENTRY; 373 } 374 table = __va(*rfte & _REGION_ENTRY_ORIGIN); 375 rc = base_region2_walk(table, addr, next, alloc); 376 if (rc) 377 return rc; 378 if (!alloc) 379 base_crst_free(table); 380 } while (rfte++, addr = next, addr < end); 381 return 0; 382 } 383 384 /** 385 * base_asce_free - free asce and tables returned from base_asce_alloc() 386 * @asce: asce to be freed 387 * 388 * Frees all region, segment, and page tables that were allocated with a 389 * corresponding base_asce_alloc() call. 390 */ 391 void base_asce_free(unsigned long asce) 392 { 393 unsigned long *table = __va(asce & _ASCE_ORIGIN); 394 395 if (!asce) 396 return; 397 switch (asce & _ASCE_TYPE_MASK) { 398 case _ASCE_TYPE_SEGMENT: 399 base_segment_walk(table, 0, _REGION3_SIZE, 0); 400 break; 401 case _ASCE_TYPE_REGION3: 402 base_region3_walk(table, 0, _REGION2_SIZE, 0); 403 break; 404 case _ASCE_TYPE_REGION2: 405 base_region2_walk(table, 0, _REGION1_SIZE, 0); 406 break; 407 case _ASCE_TYPE_REGION1: 408 base_region1_walk(table, 0, TASK_SIZE_MAX, 0); 409 break; 410 } 411 base_crst_free(table); 412 } 413 414 static int base_pgt_cache_init(void) 415 { 416 static DEFINE_MUTEX(base_pgt_cache_mutex); 417 unsigned long sz = _PAGE_TABLE_SIZE; 418 419 if (base_pgt_cache) 420 return 0; 421 mutex_lock(&base_pgt_cache_mutex); 422 if (!base_pgt_cache) 423 base_pgt_cache = kmem_cache_create("base_pgt", sz, sz, 0, NULL); 424 mutex_unlock(&base_pgt_cache_mutex); 425 return base_pgt_cache ? 0 : -ENOMEM; 426 } 427 428 /** 429 * base_asce_alloc - create kernel mapping without enhanced DAT features 430 * @addr: virtual start address of kernel mapping 431 * @num_pages: number of consecutive pages 432 * 433 * Generate an asce, including all required region, segment and page tables, 434 * that can be used to access the virtual kernel mapping. The difference is 435 * that the returned asce does not make use of any enhanced DAT features like 436 * e.g. large pages. This is required for some I/O functions that pass an 437 * asce, like e.g. some service call requests. 438 * 439 * Note: the returned asce may NEVER be attached to any cpu. It may only be 440 * used for I/O requests. tlb entries that might result because the 441 * asce was attached to a cpu won't be cleared. 442 */ 443 unsigned long base_asce_alloc(unsigned long addr, unsigned long num_pages) 444 { 445 unsigned long asce, *table, end; 446 int rc; 447 448 if (base_pgt_cache_init()) 449 return 0; 450 end = addr + num_pages * PAGE_SIZE; 451 if (end <= _REGION3_SIZE) { 452 table = base_crst_alloc(_SEGMENT_ENTRY_EMPTY); 453 if (!table) 454 return 0; 455 rc = base_segment_walk(table, addr, end, 1); 456 asce = __pa(table) | _ASCE_TYPE_SEGMENT | _ASCE_TABLE_LENGTH; 457 } else if (end <= _REGION2_SIZE) { 458 table = base_crst_alloc(_REGION3_ENTRY_EMPTY); 459 if (!table) 460 return 0; 461 rc = base_region3_walk(table, addr, end, 1); 462 asce = __pa(table) | _ASCE_TYPE_REGION3 | _ASCE_TABLE_LENGTH; 463 } else if (end <= _REGION1_SIZE) { 464 table = base_crst_alloc(_REGION2_ENTRY_EMPTY); 465 if (!table) 466 return 0; 467 rc = base_region2_walk(table, addr, end, 1); 468 asce = __pa(table) | _ASCE_TYPE_REGION2 | _ASCE_TABLE_LENGTH; 469 } else { 470 table = base_crst_alloc(_REGION1_ENTRY_EMPTY); 471 if (!table) 472 return 0; 473 rc = base_region1_walk(table, addr, end, 1); 474 asce = __pa(table) | _ASCE_TYPE_REGION1 | _ASCE_TABLE_LENGTH; 475 } 476 if (rc) { 477 base_asce_free(asce); 478 asce = 0; 479 } 480 return asce; 481 } 482