1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright IBM Corp. 2006 4 * Author(s): Heiko Carstens <heiko.carstens@de.ibm.com> 5 */ 6 7 #include <linux/memblock.h> 8 #include <linux/pfn.h> 9 #include <linux/mm.h> 10 #include <linux/init.h> 11 #include <linux/list.h> 12 #include <linux/hugetlb.h> 13 #include <linux/slab.h> 14 #include <asm/cacheflush.h> 15 #include <asm/pgalloc.h> 16 #include <asm/setup.h> 17 #include <asm/tlbflush.h> 18 #include <asm/sections.h> 19 #include <asm/set_memory.h> 20 21 static DEFINE_MUTEX(vmem_mutex); 22 23 static void __ref *vmem_alloc_pages(unsigned int order) 24 { 25 unsigned long size = PAGE_SIZE << order; 26 27 if (slab_is_available()) 28 return (void *)__get_free_pages(GFP_KERNEL, order); 29 return (void *) memblock_phys_alloc(size, size); 30 } 31 32 static void vmem_free_pages(unsigned long addr, int order) 33 { 34 /* We don't expect boot memory to be removed ever. */ 35 if (!slab_is_available() || 36 WARN_ON_ONCE(PageReserved(phys_to_page(addr)))) 37 return; 38 free_pages(addr, order); 39 } 40 41 void *vmem_crst_alloc(unsigned long val) 42 { 43 unsigned long *table; 44 45 table = vmem_alloc_pages(CRST_ALLOC_ORDER); 46 if (table) 47 crst_table_init(table, val); 48 return table; 49 } 50 51 pte_t __ref *vmem_pte_alloc(void) 52 { 53 unsigned long size = PTRS_PER_PTE * sizeof(pte_t); 54 pte_t *pte; 55 56 if (slab_is_available()) 57 pte = (pte_t *) page_table_alloc(&init_mm); 58 else 59 pte = (pte_t *) memblock_phys_alloc(size, size); 60 if (!pte) 61 return NULL; 62 memset64((u64 *)pte, _PAGE_INVALID, PTRS_PER_PTE); 63 return pte; 64 } 65 66 static void vmem_pte_free(unsigned long *table) 67 { 68 /* We don't expect boot memory to be removed ever. */ 69 if (!slab_is_available() || 70 WARN_ON_ONCE(PageReserved(virt_to_page(table)))) 71 return; 72 page_table_free(&init_mm, table); 73 } 74 75 #define PAGE_UNUSED 0xFD 76 77 /* 78 * The unused vmemmap range, which was not yet memset(PAGE_UNUSED) ranges 79 * from unused_pmd_start to next PMD_SIZE boundary. 80 */ 81 static unsigned long unused_pmd_start; 82 83 static void vmemmap_flush_unused_pmd(void) 84 { 85 if (!unused_pmd_start) 86 return; 87 memset(__va(unused_pmd_start), PAGE_UNUSED, 88 ALIGN(unused_pmd_start, PMD_SIZE) - unused_pmd_start); 89 unused_pmd_start = 0; 90 } 91 92 static void __vmemmap_use_sub_pmd(unsigned long start, unsigned long end) 93 { 94 /* 95 * As we expect to add in the same granularity as we remove, it's 96 * sufficient to mark only some piece used to block the memmap page from 97 * getting removed (just in case the memmap never gets initialized, 98 * e.g., because the memory block never gets onlined). 99 */ 100 memset(__va(start), 0, sizeof(struct page)); 101 } 102 103 static void vmemmap_use_sub_pmd(unsigned long start, unsigned long end) 104 { 105 /* 106 * We only optimize if the new used range directly follows the 107 * previously unused range (esp., when populating consecutive sections). 108 */ 109 if (unused_pmd_start == start) { 110 unused_pmd_start = end; 111 if (likely(IS_ALIGNED(unused_pmd_start, PMD_SIZE))) 112 unused_pmd_start = 0; 113 return; 114 } 115 vmemmap_flush_unused_pmd(); 116 __vmemmap_use_sub_pmd(start, end); 117 } 118 119 static void vmemmap_use_new_sub_pmd(unsigned long start, unsigned long end) 120 { 121 void *page = __va(ALIGN_DOWN(start, PMD_SIZE)); 122 123 vmemmap_flush_unused_pmd(); 124 125 /* Could be our memmap page is filled with PAGE_UNUSED already ... */ 126 __vmemmap_use_sub_pmd(start, end); 127 128 /* Mark the unused parts of the new memmap page PAGE_UNUSED. */ 129 if (!IS_ALIGNED(start, PMD_SIZE)) 130 memset(page, PAGE_UNUSED, start - __pa(page)); 131 /* 132 * We want to avoid memset(PAGE_UNUSED) when populating the vmemmap of 133 * consecutive sections. Remember for the last added PMD the last 134 * unused range in the populated PMD. 135 */ 136 if (!IS_ALIGNED(end, PMD_SIZE)) 137 unused_pmd_start = end; 138 } 139 140 /* Returns true if the PMD is completely unused and can be freed. */ 141 static bool vmemmap_unuse_sub_pmd(unsigned long start, unsigned long end) 142 { 143 void *page = __va(ALIGN_DOWN(start, PMD_SIZE)); 144 145 vmemmap_flush_unused_pmd(); 146 memset(__va(start), PAGE_UNUSED, end - start); 147 return !memchr_inv(page, PAGE_UNUSED, PMD_SIZE); 148 } 149 150 /* __ref: we'll only call vmemmap_alloc_block() via vmemmap_populate() */ 151 static int __ref modify_pte_table(pmd_t *pmd, unsigned long addr, 152 unsigned long end, bool add, bool direct) 153 { 154 unsigned long prot, pages = 0; 155 int ret = -ENOMEM; 156 pte_t *pte; 157 158 prot = pgprot_val(PAGE_KERNEL); 159 if (!MACHINE_HAS_NX) 160 prot &= ~_PAGE_NOEXEC; 161 162 pte = pte_offset_kernel(pmd, addr); 163 for (; addr < end; addr += PAGE_SIZE, pte++) { 164 if (!add) { 165 if (pte_none(*pte)) 166 continue; 167 if (!direct) 168 vmem_free_pages(pfn_to_phys(pte_pfn(*pte)), 0); 169 pte_clear(&init_mm, addr, pte); 170 } else if (pte_none(*pte)) { 171 if (!direct) { 172 void *new_page = vmemmap_alloc_block(PAGE_SIZE, NUMA_NO_NODE); 173 174 if (!new_page) 175 goto out; 176 pte_val(*pte) = __pa(new_page) | prot; 177 } else { 178 pte_val(*pte) = addr | prot; 179 } 180 } else { 181 continue; 182 } 183 pages++; 184 } 185 ret = 0; 186 out: 187 if (direct) 188 update_page_count(PG_DIRECT_MAP_4K, add ? pages : -pages); 189 return ret; 190 } 191 192 static void try_free_pte_table(pmd_t *pmd, unsigned long start) 193 { 194 pte_t *pte; 195 int i; 196 197 /* We can safely assume this is fully in 1:1 mapping & vmemmap area */ 198 pte = pte_offset_kernel(pmd, start); 199 for (i = 0; i < PTRS_PER_PTE; i++, pte++) { 200 if (!pte_none(*pte)) 201 return; 202 } 203 vmem_pte_free(__va(pmd_deref(*pmd))); 204 pmd_clear(pmd); 205 } 206 207 /* __ref: we'll only call vmemmap_alloc_block() via vmemmap_populate() */ 208 static int __ref modify_pmd_table(pud_t *pud, unsigned long addr, 209 unsigned long end, bool add, bool direct) 210 { 211 unsigned long next, prot, pages = 0; 212 int ret = -ENOMEM; 213 pmd_t *pmd; 214 pte_t *pte; 215 216 prot = pgprot_val(SEGMENT_KERNEL); 217 if (!MACHINE_HAS_NX) 218 prot &= ~_SEGMENT_ENTRY_NOEXEC; 219 220 pmd = pmd_offset(pud, addr); 221 for (; addr < end; addr = next, pmd++) { 222 next = pmd_addr_end(addr, end); 223 if (!add) { 224 if (pmd_none(*pmd)) 225 continue; 226 if (pmd_large(*pmd) && !add) { 227 if (IS_ALIGNED(addr, PMD_SIZE) && 228 IS_ALIGNED(next, PMD_SIZE)) { 229 if (!direct) 230 vmem_free_pages(pmd_deref(*pmd), get_order(PMD_SIZE)); 231 pmd_clear(pmd); 232 pages++; 233 } else if (!direct && vmemmap_unuse_sub_pmd(addr, next)) { 234 vmem_free_pages(pmd_deref(*pmd), get_order(PMD_SIZE)); 235 pmd_clear(pmd); 236 } 237 continue; 238 } 239 } else if (pmd_none(*pmd)) { 240 if (IS_ALIGNED(addr, PMD_SIZE) && 241 IS_ALIGNED(next, PMD_SIZE) && 242 MACHINE_HAS_EDAT1 && addr && direct && 243 !debug_pagealloc_enabled()) { 244 pmd_val(*pmd) = addr | prot; 245 pages++; 246 continue; 247 } else if (!direct && MACHINE_HAS_EDAT1) { 248 void *new_page; 249 250 /* 251 * Use 1MB frames for vmemmap if available. We 252 * always use large frames even if they are only 253 * partially used. Otherwise we would have also 254 * page tables since vmemmap_populate gets 255 * called for each section separately. 256 */ 257 new_page = vmemmap_alloc_block(PMD_SIZE, NUMA_NO_NODE); 258 if (new_page) { 259 pmd_val(*pmd) = __pa(new_page) | prot; 260 if (!IS_ALIGNED(addr, PMD_SIZE) || 261 !IS_ALIGNED(next, PMD_SIZE)) { 262 vmemmap_use_new_sub_pmd(addr, next); 263 } 264 continue; 265 } 266 } 267 pte = vmem_pte_alloc(); 268 if (!pte) 269 goto out; 270 pmd_populate(&init_mm, pmd, pte); 271 } else if (pmd_large(*pmd)) { 272 if (!direct) 273 vmemmap_use_sub_pmd(addr, next); 274 continue; 275 } 276 ret = modify_pte_table(pmd, addr, next, add, direct); 277 if (ret) 278 goto out; 279 if (!add) 280 try_free_pte_table(pmd, addr & PMD_MASK); 281 } 282 ret = 0; 283 out: 284 if (direct) 285 update_page_count(PG_DIRECT_MAP_1M, add ? pages : -pages); 286 return ret; 287 } 288 289 static void try_free_pmd_table(pud_t *pud, unsigned long start) 290 { 291 const unsigned long end = start + PUD_SIZE; 292 pmd_t *pmd; 293 int i; 294 295 /* Don't mess with any tables not fully in 1:1 mapping & vmemmap area */ 296 if (end > VMALLOC_START) 297 return; 298 #ifdef CONFIG_KASAN 299 if (start < KASAN_SHADOW_END && KASAN_SHADOW_START > end) 300 return; 301 #endif 302 pmd = pmd_offset(pud, start); 303 for (i = 0; i < PTRS_PER_PMD; i++, pmd++) 304 if (!pmd_none(*pmd)) 305 return; 306 vmem_free_pages(pud_deref(*pud), CRST_ALLOC_ORDER); 307 pud_clear(pud); 308 } 309 310 static int modify_pud_table(p4d_t *p4d, unsigned long addr, unsigned long end, 311 bool add, bool direct) 312 { 313 unsigned long next, prot, pages = 0; 314 int ret = -ENOMEM; 315 pud_t *pud; 316 pmd_t *pmd; 317 318 prot = pgprot_val(REGION3_KERNEL); 319 if (!MACHINE_HAS_NX) 320 prot &= ~_REGION_ENTRY_NOEXEC; 321 pud = pud_offset(p4d, addr); 322 for (; addr < end; addr = next, pud++) { 323 next = pud_addr_end(addr, end); 324 if (!add) { 325 if (pud_none(*pud)) 326 continue; 327 if (pud_large(*pud)) { 328 if (IS_ALIGNED(addr, PUD_SIZE) && 329 IS_ALIGNED(next, PUD_SIZE)) { 330 pud_clear(pud); 331 pages++; 332 } 333 continue; 334 } 335 } else if (pud_none(*pud)) { 336 if (IS_ALIGNED(addr, PUD_SIZE) && 337 IS_ALIGNED(next, PUD_SIZE) && 338 MACHINE_HAS_EDAT2 && addr && direct && 339 !debug_pagealloc_enabled()) { 340 pud_val(*pud) = addr | prot; 341 pages++; 342 continue; 343 } 344 pmd = vmem_crst_alloc(_SEGMENT_ENTRY_EMPTY); 345 if (!pmd) 346 goto out; 347 pud_populate(&init_mm, pud, pmd); 348 } else if (pud_large(*pud)) { 349 continue; 350 } 351 ret = modify_pmd_table(pud, addr, next, add, direct); 352 if (ret) 353 goto out; 354 if (!add) 355 try_free_pmd_table(pud, addr & PUD_MASK); 356 } 357 ret = 0; 358 out: 359 if (direct) 360 update_page_count(PG_DIRECT_MAP_2G, add ? pages : -pages); 361 return ret; 362 } 363 364 static void try_free_pud_table(p4d_t *p4d, unsigned long start) 365 { 366 const unsigned long end = start + P4D_SIZE; 367 pud_t *pud; 368 int i; 369 370 /* Don't mess with any tables not fully in 1:1 mapping & vmemmap area */ 371 if (end > VMALLOC_START) 372 return; 373 #ifdef CONFIG_KASAN 374 if (start < KASAN_SHADOW_END && KASAN_SHADOW_START > end) 375 return; 376 #endif 377 378 pud = pud_offset(p4d, start); 379 for (i = 0; i < PTRS_PER_PUD; i++, pud++) { 380 if (!pud_none(*pud)) 381 return; 382 } 383 vmem_free_pages(p4d_deref(*p4d), CRST_ALLOC_ORDER); 384 p4d_clear(p4d); 385 } 386 387 static int modify_p4d_table(pgd_t *pgd, unsigned long addr, unsigned long end, 388 bool add, bool direct) 389 { 390 unsigned long next; 391 int ret = -ENOMEM; 392 p4d_t *p4d; 393 pud_t *pud; 394 395 p4d = p4d_offset(pgd, addr); 396 for (; addr < end; addr = next, p4d++) { 397 next = p4d_addr_end(addr, end); 398 if (!add) { 399 if (p4d_none(*p4d)) 400 continue; 401 } else if (p4d_none(*p4d)) { 402 pud = vmem_crst_alloc(_REGION3_ENTRY_EMPTY); 403 if (!pud) 404 goto out; 405 } 406 ret = modify_pud_table(p4d, addr, next, add, direct); 407 if (ret) 408 goto out; 409 if (!add) 410 try_free_pud_table(p4d, addr & P4D_MASK); 411 } 412 ret = 0; 413 out: 414 return ret; 415 } 416 417 static void try_free_p4d_table(pgd_t *pgd, unsigned long start) 418 { 419 const unsigned long end = start + PGDIR_SIZE; 420 p4d_t *p4d; 421 int i; 422 423 /* Don't mess with any tables not fully in 1:1 mapping & vmemmap area */ 424 if (end > VMALLOC_START) 425 return; 426 #ifdef CONFIG_KASAN 427 if (start < KASAN_SHADOW_END && KASAN_SHADOW_START > end) 428 return; 429 #endif 430 431 p4d = p4d_offset(pgd, start); 432 for (i = 0; i < PTRS_PER_P4D; i++, p4d++) { 433 if (!p4d_none(*p4d)) 434 return; 435 } 436 vmem_free_pages(pgd_deref(*pgd), CRST_ALLOC_ORDER); 437 pgd_clear(pgd); 438 } 439 440 static int modify_pagetable(unsigned long start, unsigned long end, bool add, 441 bool direct) 442 { 443 unsigned long addr, next; 444 int ret = -ENOMEM; 445 pgd_t *pgd; 446 p4d_t *p4d; 447 448 if (WARN_ON_ONCE(!PAGE_ALIGNED(start | end))) 449 return -EINVAL; 450 for (addr = start; addr < end; addr = next) { 451 next = pgd_addr_end(addr, end); 452 pgd = pgd_offset_k(addr); 453 454 if (!add) { 455 if (pgd_none(*pgd)) 456 continue; 457 } else if (pgd_none(*pgd)) { 458 p4d = vmem_crst_alloc(_REGION2_ENTRY_EMPTY); 459 if (!p4d) 460 goto out; 461 pgd_populate(&init_mm, pgd, p4d); 462 } 463 ret = modify_p4d_table(pgd, addr, next, add, direct); 464 if (ret) 465 goto out; 466 if (!add) 467 try_free_p4d_table(pgd, addr & PGDIR_MASK); 468 } 469 ret = 0; 470 out: 471 if (!add) 472 flush_tlb_kernel_range(start, end); 473 return ret; 474 } 475 476 static int add_pagetable(unsigned long start, unsigned long end, bool direct) 477 { 478 return modify_pagetable(start, end, true, direct); 479 } 480 481 static int remove_pagetable(unsigned long start, unsigned long end, bool direct) 482 { 483 return modify_pagetable(start, end, false, direct); 484 } 485 486 /* 487 * Add a physical memory range to the 1:1 mapping. 488 */ 489 static int vmem_add_range(unsigned long start, unsigned long size) 490 { 491 return add_pagetable(start, start + size, true); 492 } 493 494 /* 495 * Remove a physical memory range from the 1:1 mapping. 496 */ 497 static void vmem_remove_range(unsigned long start, unsigned long size) 498 { 499 remove_pagetable(start, start + size, true); 500 } 501 502 /* 503 * Add a backed mem_map array to the virtual mem_map array. 504 */ 505 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node, 506 struct vmem_altmap *altmap) 507 { 508 int ret; 509 510 mutex_lock(&vmem_mutex); 511 /* We don't care about the node, just use NUMA_NO_NODE on allocations */ 512 ret = add_pagetable(start, end, false); 513 if (ret) 514 remove_pagetable(start, end, false); 515 mutex_unlock(&vmem_mutex); 516 return ret; 517 } 518 519 void vmemmap_free(unsigned long start, unsigned long end, 520 struct vmem_altmap *altmap) 521 { 522 mutex_lock(&vmem_mutex); 523 remove_pagetable(start, end, false); 524 mutex_unlock(&vmem_mutex); 525 } 526 527 void vmem_remove_mapping(unsigned long start, unsigned long size) 528 { 529 mutex_lock(&vmem_mutex); 530 vmem_remove_range(start, size); 531 mutex_unlock(&vmem_mutex); 532 } 533 534 int vmem_add_mapping(unsigned long start, unsigned long size) 535 { 536 int ret; 537 538 if (start + size > VMEM_MAX_PHYS || 539 start + size < start) 540 return -ERANGE; 541 542 mutex_lock(&vmem_mutex); 543 ret = vmem_add_range(start, size); 544 if (ret) 545 vmem_remove_range(start, size); 546 mutex_unlock(&vmem_mutex); 547 return ret; 548 } 549 550 /* 551 * map whole physical memory to virtual memory (identity mapping) 552 * we reserve enough space in the vmalloc area for vmemmap to hotplug 553 * additional memory segments. 554 */ 555 void __init vmem_map_init(void) 556 { 557 struct memblock_region *reg; 558 559 for_each_memblock(memory, reg) 560 vmem_add_range(reg->base, reg->size); 561 __set_memory((unsigned long)_stext, 562 (unsigned long)(_etext - _stext) >> PAGE_SHIFT, 563 SET_MEMORY_RO | SET_MEMORY_X); 564 __set_memory((unsigned long)_etext, 565 (unsigned long)(__end_rodata - _etext) >> PAGE_SHIFT, 566 SET_MEMORY_RO); 567 __set_memory((unsigned long)_sinittext, 568 (unsigned long)(_einittext - _sinittext) >> PAGE_SHIFT, 569 SET_MEMORY_RO | SET_MEMORY_X); 570 __set_memory(__stext_dma, (__etext_dma - __stext_dma) >> PAGE_SHIFT, 571 SET_MEMORY_RO | SET_MEMORY_X); 572 573 /* we need lowcore executable for our LPSWE instructions */ 574 set_memory_x(0, 1); 575 576 pr_info("Write protected kernel read-only data: %luk\n", 577 (unsigned long)(__end_rodata - _stext) >> 10); 578 } 579