1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * 4 * Copyright (C) 1995 Linus Torvalds 5 * 6 * Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999 7 */ 8 9 #include <linux/signal.h> 10 #include <linux/sched.h> 11 #include <linux/kernel.h> 12 #include <linux/errno.h> 13 #include <linux/string.h> 14 #include <linux/types.h> 15 #include <linux/ptrace.h> 16 #include <linux/mman.h> 17 #include <linux/mm.h> 18 #include <linux/hugetlb.h> 19 #include <linux/swap.h> 20 #include <linux/smp.h> 21 #include <linux/init.h> 22 #include <linux/highmem.h> 23 #include <linux/pagemap.h> 24 #include <linux/pci.h> 25 #include <linux/pfn.h> 26 #include <linux/poison.h> 27 #include <linux/memblock.h> 28 #include <linux/proc_fs.h> 29 #include <linux/memory_hotplug.h> 30 #include <linux/initrd.h> 31 #include <linux/cpumask.h> 32 #include <linux/gfp.h> 33 34 #include <asm/asm.h> 35 #include <asm/bios_ebda.h> 36 #include <asm/processor.h> 37 #include <linux/uaccess.h> 38 #include <asm/pgtable.h> 39 #include <asm/dma.h> 40 #include <asm/fixmap.h> 41 #include <asm/e820/api.h> 42 #include <asm/apic.h> 43 #include <asm/bugs.h> 44 #include <asm/tlb.h> 45 #include <asm/tlbflush.h> 46 #include <asm/olpc_ofw.h> 47 #include <asm/pgalloc.h> 48 #include <asm/sections.h> 49 #include <asm/paravirt.h> 50 #include <asm/setup.h> 51 #include <asm/set_memory.h> 52 #include <asm/page_types.h> 53 #include <asm/cpu_entry_area.h> 54 #include <asm/init.h> 55 56 #include "mm_internal.h" 57 58 unsigned long highstart_pfn, highend_pfn; 59 60 bool __read_mostly __vmalloc_start_set = false; 61 62 /* 63 * Creates a middle page table and puts a pointer to it in the 64 * given global directory entry. This only returns the gd entry 65 * in non-PAE compilation mode, since the middle layer is folded. 66 */ 67 static pmd_t * __init one_md_table_init(pgd_t *pgd) 68 { 69 p4d_t *p4d; 70 pud_t *pud; 71 pmd_t *pmd_table; 72 73 #ifdef CONFIG_X86_PAE 74 if (!(pgd_val(*pgd) & _PAGE_PRESENT)) { 75 pmd_table = (pmd_t *)alloc_low_page(); 76 paravirt_alloc_pmd(&init_mm, __pa(pmd_table) >> PAGE_SHIFT); 77 set_pgd(pgd, __pgd(__pa(pmd_table) | _PAGE_PRESENT)); 78 p4d = p4d_offset(pgd, 0); 79 pud = pud_offset(p4d, 0); 80 BUG_ON(pmd_table != pmd_offset(pud, 0)); 81 82 return pmd_table; 83 } 84 #endif 85 p4d = p4d_offset(pgd, 0); 86 pud = pud_offset(p4d, 0); 87 pmd_table = pmd_offset(pud, 0); 88 89 return pmd_table; 90 } 91 92 /* 93 * Create a page table and place a pointer to it in a middle page 94 * directory entry: 95 */ 96 static pte_t * __init one_page_table_init(pmd_t *pmd) 97 { 98 if (!(pmd_val(*pmd) & _PAGE_PRESENT)) { 99 pte_t *page_table = (pte_t *)alloc_low_page(); 100 101 paravirt_alloc_pte(&init_mm, __pa(page_table) >> PAGE_SHIFT); 102 set_pmd(pmd, __pmd(__pa(page_table) | _PAGE_TABLE)); 103 BUG_ON(page_table != pte_offset_kernel(pmd, 0)); 104 } 105 106 return pte_offset_kernel(pmd, 0); 107 } 108 109 pmd_t * __init populate_extra_pmd(unsigned long vaddr) 110 { 111 int pgd_idx = pgd_index(vaddr); 112 int pmd_idx = pmd_index(vaddr); 113 114 return one_md_table_init(swapper_pg_dir + pgd_idx) + pmd_idx; 115 } 116 117 pte_t * __init populate_extra_pte(unsigned long vaddr) 118 { 119 int pte_idx = pte_index(vaddr); 120 pmd_t *pmd; 121 122 pmd = populate_extra_pmd(vaddr); 123 return one_page_table_init(pmd) + pte_idx; 124 } 125 126 static unsigned long __init 127 page_table_range_init_count(unsigned long start, unsigned long end) 128 { 129 unsigned long count = 0; 130 #ifdef CONFIG_HIGHMEM 131 int pmd_idx_kmap_begin = fix_to_virt(FIX_KMAP_END) >> PMD_SHIFT; 132 int pmd_idx_kmap_end = fix_to_virt(FIX_KMAP_BEGIN) >> PMD_SHIFT; 133 int pgd_idx, pmd_idx; 134 unsigned long vaddr; 135 136 if (pmd_idx_kmap_begin == pmd_idx_kmap_end) 137 return 0; 138 139 vaddr = start; 140 pgd_idx = pgd_index(vaddr); 141 pmd_idx = pmd_index(vaddr); 142 143 for ( ; (pgd_idx < PTRS_PER_PGD) && (vaddr != end); pgd_idx++) { 144 for (; (pmd_idx < PTRS_PER_PMD) && (vaddr != end); 145 pmd_idx++) { 146 if ((vaddr >> PMD_SHIFT) >= pmd_idx_kmap_begin && 147 (vaddr >> PMD_SHIFT) <= pmd_idx_kmap_end) 148 count++; 149 vaddr += PMD_SIZE; 150 } 151 pmd_idx = 0; 152 } 153 #endif 154 return count; 155 } 156 157 static pte_t *__init page_table_kmap_check(pte_t *pte, pmd_t *pmd, 158 unsigned long vaddr, pte_t *lastpte, 159 void **adr) 160 { 161 #ifdef CONFIG_HIGHMEM 162 /* 163 * Something (early fixmap) may already have put a pte 164 * page here, which causes the page table allocation 165 * to become nonlinear. Attempt to fix it, and if it 166 * is still nonlinear then we have to bug. 167 */ 168 int pmd_idx_kmap_begin = fix_to_virt(FIX_KMAP_END) >> PMD_SHIFT; 169 int pmd_idx_kmap_end = fix_to_virt(FIX_KMAP_BEGIN) >> PMD_SHIFT; 170 171 if (pmd_idx_kmap_begin != pmd_idx_kmap_end 172 && (vaddr >> PMD_SHIFT) >= pmd_idx_kmap_begin 173 && (vaddr >> PMD_SHIFT) <= pmd_idx_kmap_end) { 174 pte_t *newpte; 175 int i; 176 177 BUG_ON(after_bootmem); 178 newpte = *adr; 179 for (i = 0; i < PTRS_PER_PTE; i++) 180 set_pte(newpte + i, pte[i]); 181 *adr = (void *)(((unsigned long)(*adr)) + PAGE_SIZE); 182 183 paravirt_alloc_pte(&init_mm, __pa(newpte) >> PAGE_SHIFT); 184 set_pmd(pmd, __pmd(__pa(newpte)|_PAGE_TABLE)); 185 BUG_ON(newpte != pte_offset_kernel(pmd, 0)); 186 __flush_tlb_all(); 187 188 paravirt_release_pte(__pa(pte) >> PAGE_SHIFT); 189 pte = newpte; 190 } 191 BUG_ON(vaddr < fix_to_virt(FIX_KMAP_BEGIN - 1) 192 && vaddr > fix_to_virt(FIX_KMAP_END) 193 && lastpte && lastpte + PTRS_PER_PTE != pte); 194 #endif 195 return pte; 196 } 197 198 /* 199 * This function initializes a certain range of kernel virtual memory 200 * with new bootmem page tables, everywhere page tables are missing in 201 * the given range. 202 * 203 * NOTE: The pagetables are allocated contiguous on the physical space 204 * so we can cache the place of the first one and move around without 205 * checking the pgd every time. 206 */ 207 static void __init 208 page_table_range_init(unsigned long start, unsigned long end, pgd_t *pgd_base) 209 { 210 int pgd_idx, pmd_idx; 211 unsigned long vaddr; 212 pgd_t *pgd; 213 pmd_t *pmd; 214 pte_t *pte = NULL; 215 unsigned long count = page_table_range_init_count(start, end); 216 void *adr = NULL; 217 218 if (count) 219 adr = alloc_low_pages(count); 220 221 vaddr = start; 222 pgd_idx = pgd_index(vaddr); 223 pmd_idx = pmd_index(vaddr); 224 pgd = pgd_base + pgd_idx; 225 226 for ( ; (pgd_idx < PTRS_PER_PGD) && (vaddr != end); pgd++, pgd_idx++) { 227 pmd = one_md_table_init(pgd); 228 pmd = pmd + pmd_index(vaddr); 229 for (; (pmd_idx < PTRS_PER_PMD) && (vaddr != end); 230 pmd++, pmd_idx++) { 231 pte = page_table_kmap_check(one_page_table_init(pmd), 232 pmd, vaddr, pte, &adr); 233 234 vaddr += PMD_SIZE; 235 } 236 pmd_idx = 0; 237 } 238 } 239 240 static inline int is_kernel_text(unsigned long addr) 241 { 242 if (addr >= (unsigned long)_text && addr <= (unsigned long)__init_end) 243 return 1; 244 return 0; 245 } 246 247 /* 248 * This maps the physical memory to kernel virtual address space, a total 249 * of max_low_pfn pages, by creating page tables starting from address 250 * PAGE_OFFSET: 251 */ 252 unsigned long __init 253 kernel_physical_mapping_init(unsigned long start, 254 unsigned long end, 255 unsigned long page_size_mask) 256 { 257 int use_pse = page_size_mask == (1<<PG_LEVEL_2M); 258 unsigned long last_map_addr = end; 259 unsigned long start_pfn, end_pfn; 260 pgd_t *pgd_base = swapper_pg_dir; 261 int pgd_idx, pmd_idx, pte_ofs; 262 unsigned long pfn; 263 pgd_t *pgd; 264 pmd_t *pmd; 265 pte_t *pte; 266 unsigned pages_2m, pages_4k; 267 int mapping_iter; 268 269 start_pfn = start >> PAGE_SHIFT; 270 end_pfn = end >> PAGE_SHIFT; 271 272 /* 273 * First iteration will setup identity mapping using large/small pages 274 * based on use_pse, with other attributes same as set by 275 * the early code in head_32.S 276 * 277 * Second iteration will setup the appropriate attributes (NX, GLOBAL..) 278 * as desired for the kernel identity mapping. 279 * 280 * This two pass mechanism conforms to the TLB app note which says: 281 * 282 * "Software should not write to a paging-structure entry in a way 283 * that would change, for any linear address, both the page size 284 * and either the page frame or attributes." 285 */ 286 mapping_iter = 1; 287 288 if (!boot_cpu_has(X86_FEATURE_PSE)) 289 use_pse = 0; 290 291 repeat: 292 pages_2m = pages_4k = 0; 293 pfn = start_pfn; 294 pgd_idx = pgd_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET); 295 pgd = pgd_base + pgd_idx; 296 for (; pgd_idx < PTRS_PER_PGD; pgd++, pgd_idx++) { 297 pmd = one_md_table_init(pgd); 298 299 if (pfn >= end_pfn) 300 continue; 301 #ifdef CONFIG_X86_PAE 302 pmd_idx = pmd_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET); 303 pmd += pmd_idx; 304 #else 305 pmd_idx = 0; 306 #endif 307 for (; pmd_idx < PTRS_PER_PMD && pfn < end_pfn; 308 pmd++, pmd_idx++) { 309 unsigned int addr = pfn * PAGE_SIZE + PAGE_OFFSET; 310 311 /* 312 * Map with big pages if possible, otherwise 313 * create normal page tables: 314 */ 315 if (use_pse) { 316 unsigned int addr2; 317 pgprot_t prot = PAGE_KERNEL_LARGE; 318 /* 319 * first pass will use the same initial 320 * identity mapping attribute + _PAGE_PSE. 321 */ 322 pgprot_t init_prot = 323 __pgprot(PTE_IDENT_ATTR | 324 _PAGE_PSE); 325 326 pfn &= PMD_MASK >> PAGE_SHIFT; 327 addr2 = (pfn + PTRS_PER_PTE-1) * PAGE_SIZE + 328 PAGE_OFFSET + PAGE_SIZE-1; 329 330 if (is_kernel_text(addr) || 331 is_kernel_text(addr2)) 332 prot = PAGE_KERNEL_LARGE_EXEC; 333 334 pages_2m++; 335 if (mapping_iter == 1) 336 set_pmd(pmd, pfn_pmd(pfn, init_prot)); 337 else 338 set_pmd(pmd, pfn_pmd(pfn, prot)); 339 340 pfn += PTRS_PER_PTE; 341 continue; 342 } 343 pte = one_page_table_init(pmd); 344 345 pte_ofs = pte_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET); 346 pte += pte_ofs; 347 for (; pte_ofs < PTRS_PER_PTE && pfn < end_pfn; 348 pte++, pfn++, pte_ofs++, addr += PAGE_SIZE) { 349 pgprot_t prot = PAGE_KERNEL; 350 /* 351 * first pass will use the same initial 352 * identity mapping attribute. 353 */ 354 pgprot_t init_prot = __pgprot(PTE_IDENT_ATTR); 355 356 if (is_kernel_text(addr)) 357 prot = PAGE_KERNEL_EXEC; 358 359 pages_4k++; 360 if (mapping_iter == 1) { 361 set_pte(pte, pfn_pte(pfn, init_prot)); 362 last_map_addr = (pfn << PAGE_SHIFT) + PAGE_SIZE; 363 } else 364 set_pte(pte, pfn_pte(pfn, prot)); 365 } 366 } 367 } 368 if (mapping_iter == 1) { 369 /* 370 * update direct mapping page count only in the first 371 * iteration. 372 */ 373 update_page_count(PG_LEVEL_2M, pages_2m); 374 update_page_count(PG_LEVEL_4K, pages_4k); 375 376 /* 377 * local global flush tlb, which will flush the previous 378 * mappings present in both small and large page TLB's. 379 */ 380 __flush_tlb_all(); 381 382 /* 383 * Second iteration will set the actual desired PTE attributes. 384 */ 385 mapping_iter = 2; 386 goto repeat; 387 } 388 return last_map_addr; 389 } 390 391 pte_t *kmap_pte; 392 393 static inline pte_t *kmap_get_fixmap_pte(unsigned long vaddr) 394 { 395 pgd_t *pgd = pgd_offset_k(vaddr); 396 p4d_t *p4d = p4d_offset(pgd, vaddr); 397 pud_t *pud = pud_offset(p4d, vaddr); 398 pmd_t *pmd = pmd_offset(pud, vaddr); 399 return pte_offset_kernel(pmd, vaddr); 400 } 401 402 static void __init kmap_init(void) 403 { 404 unsigned long kmap_vstart; 405 406 /* 407 * Cache the first kmap pte: 408 */ 409 kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN); 410 kmap_pte = kmap_get_fixmap_pte(kmap_vstart); 411 } 412 413 #ifdef CONFIG_HIGHMEM 414 static void __init permanent_kmaps_init(pgd_t *pgd_base) 415 { 416 unsigned long vaddr; 417 pgd_t *pgd; 418 p4d_t *p4d; 419 pud_t *pud; 420 pmd_t *pmd; 421 pte_t *pte; 422 423 vaddr = PKMAP_BASE; 424 page_table_range_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, pgd_base); 425 426 pgd = swapper_pg_dir + pgd_index(vaddr); 427 p4d = p4d_offset(pgd, vaddr); 428 pud = pud_offset(p4d, vaddr); 429 pmd = pmd_offset(pud, vaddr); 430 pte = pte_offset_kernel(pmd, vaddr); 431 pkmap_page_table = pte; 432 } 433 434 void __init add_highpages_with_active_regions(int nid, 435 unsigned long start_pfn, unsigned long end_pfn) 436 { 437 phys_addr_t start, end; 438 u64 i; 439 440 for_each_free_mem_range(i, nid, MEMBLOCK_NONE, &start, &end, NULL) { 441 unsigned long pfn = clamp_t(unsigned long, PFN_UP(start), 442 start_pfn, end_pfn); 443 unsigned long e_pfn = clamp_t(unsigned long, PFN_DOWN(end), 444 start_pfn, end_pfn); 445 for ( ; pfn < e_pfn; pfn++) 446 if (pfn_valid(pfn)) 447 free_highmem_page(pfn_to_page(pfn)); 448 } 449 } 450 #else 451 static inline void permanent_kmaps_init(pgd_t *pgd_base) 452 { 453 } 454 #endif /* CONFIG_HIGHMEM */ 455 456 void __init sync_initial_page_table(void) 457 { 458 clone_pgd_range(initial_page_table + KERNEL_PGD_BOUNDARY, 459 swapper_pg_dir + KERNEL_PGD_BOUNDARY, 460 KERNEL_PGD_PTRS); 461 462 /* 463 * sync back low identity map too. It is used for example 464 * in the 32-bit EFI stub. 465 */ 466 clone_pgd_range(initial_page_table, 467 swapper_pg_dir + KERNEL_PGD_BOUNDARY, 468 min(KERNEL_PGD_PTRS, KERNEL_PGD_BOUNDARY)); 469 } 470 471 void __init native_pagetable_init(void) 472 { 473 unsigned long pfn, va; 474 pgd_t *pgd, *base = swapper_pg_dir; 475 p4d_t *p4d; 476 pud_t *pud; 477 pmd_t *pmd; 478 pte_t *pte; 479 480 /* 481 * Remove any mappings which extend past the end of physical 482 * memory from the boot time page table. 483 * In virtual address space, we should have at least two pages 484 * from VMALLOC_END to pkmap or fixmap according to VMALLOC_END 485 * definition. And max_low_pfn is set to VMALLOC_END physical 486 * address. If initial memory mapping is doing right job, we 487 * should have pte used near max_low_pfn or one pmd is not present. 488 */ 489 for (pfn = max_low_pfn; pfn < 1<<(32-PAGE_SHIFT); pfn++) { 490 va = PAGE_OFFSET + (pfn<<PAGE_SHIFT); 491 pgd = base + pgd_index(va); 492 if (!pgd_present(*pgd)) 493 break; 494 495 p4d = p4d_offset(pgd, va); 496 pud = pud_offset(p4d, va); 497 pmd = pmd_offset(pud, va); 498 if (!pmd_present(*pmd)) 499 break; 500 501 /* should not be large page here */ 502 if (pmd_large(*pmd)) { 503 pr_warn("try to clear pte for ram above max_low_pfn: pfn: %lx pmd: %p pmd phys: %lx, but pmd is big page and is not using pte !\n", 504 pfn, pmd, __pa(pmd)); 505 BUG_ON(1); 506 } 507 508 pte = pte_offset_kernel(pmd, va); 509 if (!pte_present(*pte)) 510 break; 511 512 printk(KERN_DEBUG "clearing pte for ram above max_low_pfn: pfn: %lx pmd: %p pmd phys: %lx pte: %p pte phys: %lx\n", 513 pfn, pmd, __pa(pmd), pte, __pa(pte)); 514 pte_clear(NULL, va, pte); 515 } 516 paravirt_alloc_pmd(&init_mm, __pa(base) >> PAGE_SHIFT); 517 paging_init(); 518 } 519 520 /* 521 * Build a proper pagetable for the kernel mappings. Up until this 522 * point, we've been running on some set of pagetables constructed by 523 * the boot process. 524 * 525 * If we're booting on native hardware, this will be a pagetable 526 * constructed in arch/x86/kernel/head_32.S. The root of the 527 * pagetable will be swapper_pg_dir. 528 * 529 * If we're booting paravirtualized under a hypervisor, then there are 530 * more options: we may already be running PAE, and the pagetable may 531 * or may not be based in swapper_pg_dir. In any case, 532 * paravirt_pagetable_init() will set up swapper_pg_dir 533 * appropriately for the rest of the initialization to work. 534 * 535 * In general, pagetable_init() assumes that the pagetable may already 536 * be partially populated, and so it avoids stomping on any existing 537 * mappings. 538 */ 539 void __init early_ioremap_page_table_range_init(void) 540 { 541 pgd_t *pgd_base = swapper_pg_dir; 542 unsigned long vaddr, end; 543 544 /* 545 * Fixed mappings, only the page table structure has to be 546 * created - mappings will be set by set_fixmap(): 547 */ 548 vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK; 549 end = (FIXADDR_TOP + PMD_SIZE - 1) & PMD_MASK; 550 page_table_range_init(vaddr, end, pgd_base); 551 early_ioremap_reset(); 552 } 553 554 static void __init pagetable_init(void) 555 { 556 pgd_t *pgd_base = swapper_pg_dir; 557 558 permanent_kmaps_init(pgd_base); 559 } 560 561 #define DEFAULT_PTE_MASK ~(_PAGE_NX | _PAGE_GLOBAL) 562 /* Bits supported by the hardware: */ 563 pteval_t __supported_pte_mask __read_mostly = DEFAULT_PTE_MASK; 564 /* Bits allowed in normal kernel mappings: */ 565 pteval_t __default_kernel_pte_mask __read_mostly = DEFAULT_PTE_MASK; 566 EXPORT_SYMBOL_GPL(__supported_pte_mask); 567 /* Used in PAGE_KERNEL_* macros which are reasonably used out-of-tree: */ 568 EXPORT_SYMBOL(__default_kernel_pte_mask); 569 570 /* user-defined highmem size */ 571 static unsigned int highmem_pages = -1; 572 573 /* 574 * highmem=size forces highmem to be exactly 'size' bytes. 575 * This works even on boxes that have no highmem otherwise. 576 * This also works to reduce highmem size on bigger boxes. 577 */ 578 static int __init parse_highmem(char *arg) 579 { 580 if (!arg) 581 return -EINVAL; 582 583 highmem_pages = memparse(arg, &arg) >> PAGE_SHIFT; 584 return 0; 585 } 586 early_param("highmem", parse_highmem); 587 588 #define MSG_HIGHMEM_TOO_BIG \ 589 "highmem size (%luMB) is bigger than pages available (%luMB)!\n" 590 591 #define MSG_LOWMEM_TOO_SMALL \ 592 "highmem size (%luMB) results in <64MB lowmem, ignoring it!\n" 593 /* 594 * All of RAM fits into lowmem - but if user wants highmem 595 * artificially via the highmem=x boot parameter then create 596 * it: 597 */ 598 static void __init lowmem_pfn_init(void) 599 { 600 /* max_low_pfn is 0, we already have early_res support */ 601 max_low_pfn = max_pfn; 602 603 if (highmem_pages == -1) 604 highmem_pages = 0; 605 #ifdef CONFIG_HIGHMEM 606 if (highmem_pages >= max_pfn) { 607 printk(KERN_ERR MSG_HIGHMEM_TOO_BIG, 608 pages_to_mb(highmem_pages), pages_to_mb(max_pfn)); 609 highmem_pages = 0; 610 } 611 if (highmem_pages) { 612 if (max_low_pfn - highmem_pages < 64*1024*1024/PAGE_SIZE) { 613 printk(KERN_ERR MSG_LOWMEM_TOO_SMALL, 614 pages_to_mb(highmem_pages)); 615 highmem_pages = 0; 616 } 617 max_low_pfn -= highmem_pages; 618 } 619 #else 620 if (highmem_pages) 621 printk(KERN_ERR "ignoring highmem size on non-highmem kernel!\n"); 622 #endif 623 } 624 625 #define MSG_HIGHMEM_TOO_SMALL \ 626 "only %luMB highmem pages available, ignoring highmem size of %luMB!\n" 627 628 #define MSG_HIGHMEM_TRIMMED \ 629 "Warning: only 4GB will be used. Use a HIGHMEM64G enabled kernel!\n" 630 /* 631 * We have more RAM than fits into lowmem - we try to put it into 632 * highmem, also taking the highmem=x boot parameter into account: 633 */ 634 static void __init highmem_pfn_init(void) 635 { 636 max_low_pfn = MAXMEM_PFN; 637 638 if (highmem_pages == -1) 639 highmem_pages = max_pfn - MAXMEM_PFN; 640 641 if (highmem_pages + MAXMEM_PFN < max_pfn) 642 max_pfn = MAXMEM_PFN + highmem_pages; 643 644 if (highmem_pages + MAXMEM_PFN > max_pfn) { 645 printk(KERN_WARNING MSG_HIGHMEM_TOO_SMALL, 646 pages_to_mb(max_pfn - MAXMEM_PFN), 647 pages_to_mb(highmem_pages)); 648 highmem_pages = 0; 649 } 650 #ifndef CONFIG_HIGHMEM 651 /* Maximum memory usable is what is directly addressable */ 652 printk(KERN_WARNING "Warning only %ldMB will be used.\n", MAXMEM>>20); 653 if (max_pfn > MAX_NONPAE_PFN) 654 printk(KERN_WARNING "Use a HIGHMEM64G enabled kernel.\n"); 655 else 656 printk(KERN_WARNING "Use a HIGHMEM enabled kernel.\n"); 657 max_pfn = MAXMEM_PFN; 658 #else /* !CONFIG_HIGHMEM */ 659 #ifndef CONFIG_HIGHMEM64G 660 if (max_pfn > MAX_NONPAE_PFN) { 661 max_pfn = MAX_NONPAE_PFN; 662 printk(KERN_WARNING MSG_HIGHMEM_TRIMMED); 663 } 664 #endif /* !CONFIG_HIGHMEM64G */ 665 #endif /* !CONFIG_HIGHMEM */ 666 } 667 668 /* 669 * Determine low and high memory ranges: 670 */ 671 void __init find_low_pfn_range(void) 672 { 673 /* it could update max_pfn */ 674 675 if (max_pfn <= MAXMEM_PFN) 676 lowmem_pfn_init(); 677 else 678 highmem_pfn_init(); 679 } 680 681 #ifndef CONFIG_NEED_MULTIPLE_NODES 682 void __init initmem_init(void) 683 { 684 #ifdef CONFIG_HIGHMEM 685 highstart_pfn = highend_pfn = max_pfn; 686 if (max_pfn > max_low_pfn) 687 highstart_pfn = max_low_pfn; 688 printk(KERN_NOTICE "%ldMB HIGHMEM available.\n", 689 pages_to_mb(highend_pfn - highstart_pfn)); 690 high_memory = (void *) __va(highstart_pfn * PAGE_SIZE - 1) + 1; 691 #else 692 high_memory = (void *) __va(max_low_pfn * PAGE_SIZE - 1) + 1; 693 #endif 694 695 memblock_set_node(0, PHYS_ADDR_MAX, &memblock.memory, 0); 696 sparse_memory_present_with_active_regions(0); 697 698 #ifdef CONFIG_FLATMEM 699 max_mapnr = IS_ENABLED(CONFIG_HIGHMEM) ? highend_pfn : max_low_pfn; 700 #endif 701 __vmalloc_start_set = true; 702 703 printk(KERN_NOTICE "%ldMB LOWMEM available.\n", 704 pages_to_mb(max_low_pfn)); 705 706 setup_bootmem_allocator(); 707 } 708 #endif /* !CONFIG_NEED_MULTIPLE_NODES */ 709 710 void __init setup_bootmem_allocator(void) 711 { 712 printk(KERN_INFO " mapped low ram: 0 - %08lx\n", 713 max_pfn_mapped<<PAGE_SHIFT); 714 printk(KERN_INFO " low ram: 0 - %08lx\n", max_low_pfn<<PAGE_SHIFT); 715 } 716 717 /* 718 * paging_init() sets up the page tables - note that the first 8MB are 719 * already mapped by head.S. 720 * 721 * This routines also unmaps the page at virtual kernel address 0, so 722 * that we can trap those pesky NULL-reference errors in the kernel. 723 */ 724 void __init paging_init(void) 725 { 726 pagetable_init(); 727 728 __flush_tlb_all(); 729 730 kmap_init(); 731 732 /* 733 * NOTE: at this point the bootmem allocator is fully available. 734 */ 735 olpc_dt_build_devicetree(); 736 sparse_memory_present_with_active_regions(MAX_NUMNODES); 737 sparse_init(); 738 zone_sizes_init(); 739 } 740 741 /* 742 * Test if the WP bit works in supervisor mode. It isn't supported on 386's 743 * and also on some strange 486's. All 586+'s are OK. This used to involve 744 * black magic jumps to work around some nasty CPU bugs, but fortunately the 745 * switch to using exceptions got rid of all that. 746 */ 747 static void __init test_wp_bit(void) 748 { 749 char z = 0; 750 751 printk(KERN_INFO "Checking if this processor honours the WP bit even in supervisor mode..."); 752 753 __set_fixmap(FIX_WP_TEST, __pa_symbol(empty_zero_page), PAGE_KERNEL_RO); 754 755 if (probe_kernel_write((char *)fix_to_virt(FIX_WP_TEST), &z, 1)) { 756 clear_fixmap(FIX_WP_TEST); 757 printk(KERN_CONT "Ok.\n"); 758 return; 759 } 760 761 printk(KERN_CONT "No.\n"); 762 panic("Linux doesn't support CPUs with broken WP."); 763 } 764 765 void __init mem_init(void) 766 { 767 pci_iommu_alloc(); 768 769 #ifdef CONFIG_FLATMEM 770 BUG_ON(!mem_map); 771 #endif 772 /* 773 * With CONFIG_DEBUG_PAGEALLOC initialization of highmem pages has to 774 * be done before memblock_free_all(). Memblock use free low memory for 775 * temporary data (see find_range_array()) and for this purpose can use 776 * pages that was already passed to the buddy allocator, hence marked as 777 * not accessible in the page tables when compiled with 778 * CONFIG_DEBUG_PAGEALLOC. Otherwise order of initialization is not 779 * important here. 780 */ 781 set_highmem_pages_init(); 782 783 /* this will put all low memory onto the freelists */ 784 memblock_free_all(); 785 786 after_bootmem = 1; 787 x86_init.hyper.init_after_bootmem(); 788 789 mem_init_print_info(NULL); 790 printk(KERN_INFO "virtual kernel memory layout:\n" 791 " fixmap : 0x%08lx - 0x%08lx (%4ld kB)\n" 792 " cpu_entry : 0x%08lx - 0x%08lx (%4ld kB)\n" 793 #ifdef CONFIG_HIGHMEM 794 " pkmap : 0x%08lx - 0x%08lx (%4ld kB)\n" 795 #endif 796 " vmalloc : 0x%08lx - 0x%08lx (%4ld MB)\n" 797 " lowmem : 0x%08lx - 0x%08lx (%4ld MB)\n" 798 " .init : 0x%08lx - 0x%08lx (%4ld kB)\n" 799 " .data : 0x%08lx - 0x%08lx (%4ld kB)\n" 800 " .text : 0x%08lx - 0x%08lx (%4ld kB)\n", 801 FIXADDR_START, FIXADDR_TOP, 802 (FIXADDR_TOP - FIXADDR_START) >> 10, 803 804 CPU_ENTRY_AREA_BASE, 805 CPU_ENTRY_AREA_BASE + CPU_ENTRY_AREA_MAP_SIZE, 806 CPU_ENTRY_AREA_MAP_SIZE >> 10, 807 808 #ifdef CONFIG_HIGHMEM 809 PKMAP_BASE, PKMAP_BASE+LAST_PKMAP*PAGE_SIZE, 810 (LAST_PKMAP*PAGE_SIZE) >> 10, 811 #endif 812 813 VMALLOC_START, VMALLOC_END, 814 (VMALLOC_END - VMALLOC_START) >> 20, 815 816 (unsigned long)__va(0), (unsigned long)high_memory, 817 ((unsigned long)high_memory - (unsigned long)__va(0)) >> 20, 818 819 (unsigned long)&__init_begin, (unsigned long)&__init_end, 820 ((unsigned long)&__init_end - 821 (unsigned long)&__init_begin) >> 10, 822 823 (unsigned long)&_etext, (unsigned long)&_edata, 824 ((unsigned long)&_edata - (unsigned long)&_etext) >> 10, 825 826 (unsigned long)&_text, (unsigned long)&_etext, 827 ((unsigned long)&_etext - (unsigned long)&_text) >> 10); 828 829 /* 830 * Check boundaries twice: Some fundamental inconsistencies can 831 * be detected at build time already. 832 */ 833 #define __FIXADDR_TOP (-PAGE_SIZE) 834 #ifdef CONFIG_HIGHMEM 835 BUILD_BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE > FIXADDR_START); 836 BUILD_BUG_ON(VMALLOC_END > PKMAP_BASE); 837 #endif 838 #define high_memory (-128UL << 20) 839 BUILD_BUG_ON(VMALLOC_START >= VMALLOC_END); 840 #undef high_memory 841 #undef __FIXADDR_TOP 842 843 #ifdef CONFIG_HIGHMEM 844 BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE > FIXADDR_START); 845 BUG_ON(VMALLOC_END > PKMAP_BASE); 846 #endif 847 BUG_ON(VMALLOC_START >= VMALLOC_END); 848 BUG_ON((unsigned long)high_memory > VMALLOC_START); 849 850 test_wp_bit(); 851 } 852 853 #ifdef CONFIG_MEMORY_HOTPLUG 854 int arch_add_memory(int nid, u64 start, u64 size, 855 struct mhp_restrictions *restrictions) 856 { 857 unsigned long start_pfn = start >> PAGE_SHIFT; 858 unsigned long nr_pages = size >> PAGE_SHIFT; 859 860 return __add_pages(nid, start_pfn, nr_pages, restrictions); 861 } 862 863 void arch_remove_memory(int nid, u64 start, u64 size, 864 struct vmem_altmap *altmap) 865 { 866 unsigned long start_pfn = start >> PAGE_SHIFT; 867 unsigned long nr_pages = size >> PAGE_SHIFT; 868 struct zone *zone; 869 870 zone = page_zone(pfn_to_page(start_pfn)); 871 __remove_pages(zone, start_pfn, nr_pages, altmap); 872 } 873 #endif 874 875 int kernel_set_to_readonly __read_mostly; 876 877 static void mark_nxdata_nx(void) 878 { 879 /* 880 * When this called, init has already been executed and released, 881 * so everything past _etext should be NX. 882 */ 883 unsigned long start = PFN_ALIGN(_etext); 884 /* 885 * This comes from is_kernel_text upper limit. Also HPAGE where used: 886 */ 887 unsigned long size = (((unsigned long)__init_end + HPAGE_SIZE) & HPAGE_MASK) - start; 888 889 if (__supported_pte_mask & _PAGE_NX) 890 printk(KERN_INFO "NX-protecting the kernel data: %luk\n", size >> 10); 891 set_memory_nx(start, size >> PAGE_SHIFT); 892 } 893 894 void mark_rodata_ro(void) 895 { 896 unsigned long start = PFN_ALIGN(_text); 897 unsigned long size = (unsigned long)__end_rodata - start; 898 899 set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT); 900 pr_info("Write protecting kernel text and read-only data: %luk\n", 901 size >> 10); 902 903 kernel_set_to_readonly = 1; 904 905 #ifdef CONFIG_CPA_DEBUG 906 pr_info("Testing CPA: Reverting %lx-%lx\n", start, start + size); 907 set_pages_rw(virt_to_page(start), size >> PAGE_SHIFT); 908 909 pr_info("Testing CPA: write protecting again\n"); 910 set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT); 911 #endif 912 mark_nxdata_nx(); 913 if (__supported_pte_mask & _PAGE_NX) 914 debug_checkwx(); 915 } 916