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 #include <asm/pgtable_areas.h> 56 57 #include "mm_internal.h" 58 59 unsigned long highstart_pfn, highend_pfn; 60 61 bool __read_mostly __vmalloc_start_set = false; 62 63 /* 64 * Creates a middle page table and puts a pointer to it in the 65 * given global directory entry. This only returns the gd entry 66 * in non-PAE compilation mode, since the middle layer is folded. 67 */ 68 static pmd_t * __init one_md_table_init(pgd_t *pgd) 69 { 70 p4d_t *p4d; 71 pud_t *pud; 72 pmd_t *pmd_table; 73 74 #ifdef CONFIG_X86_PAE 75 if (!(pgd_val(*pgd) & _PAGE_PRESENT)) { 76 pmd_table = (pmd_t *)alloc_low_page(); 77 paravirt_alloc_pmd(&init_mm, __pa(pmd_table) >> PAGE_SHIFT); 78 set_pgd(pgd, __pgd(__pa(pmd_table) | _PAGE_PRESENT)); 79 p4d = p4d_offset(pgd, 0); 80 pud = pud_offset(p4d, 0); 81 BUG_ON(pmd_table != pmd_offset(pud, 0)); 82 83 return pmd_table; 84 } 85 #endif 86 p4d = p4d_offset(pgd, 0); 87 pud = pud_offset(p4d, 0); 88 pmd_table = pmd_offset(pud, 0); 89 90 return pmd_table; 91 } 92 93 /* 94 * Create a page table and place a pointer to it in a middle page 95 * directory entry: 96 */ 97 static pte_t * __init one_page_table_init(pmd_t *pmd) 98 { 99 if (!(pmd_val(*pmd) & _PAGE_PRESENT)) { 100 pte_t *page_table = (pte_t *)alloc_low_page(); 101 102 paravirt_alloc_pte(&init_mm, __pa(page_table) >> PAGE_SHIFT); 103 set_pmd(pmd, __pmd(__pa(page_table) | _PAGE_TABLE)); 104 BUG_ON(page_table != pte_offset_kernel(pmd, 0)); 105 } 106 107 return pte_offset_kernel(pmd, 0); 108 } 109 110 pmd_t * __init populate_extra_pmd(unsigned long vaddr) 111 { 112 int pgd_idx = pgd_index(vaddr); 113 int pmd_idx = pmd_index(vaddr); 114 115 return one_md_table_init(swapper_pg_dir + pgd_idx) + pmd_idx; 116 } 117 118 pte_t * __init populate_extra_pte(unsigned long vaddr) 119 { 120 int pte_idx = pte_index(vaddr); 121 pmd_t *pmd; 122 123 pmd = populate_extra_pmd(vaddr); 124 return one_page_table_init(pmd) + pte_idx; 125 } 126 127 static unsigned long __init 128 page_table_range_init_count(unsigned long start, unsigned long end) 129 { 130 unsigned long count = 0; 131 #ifdef CONFIG_HIGHMEM 132 int pmd_idx_kmap_begin = fix_to_virt(FIX_KMAP_END) >> PMD_SHIFT; 133 int pmd_idx_kmap_end = fix_to_virt(FIX_KMAP_BEGIN) >> PMD_SHIFT; 134 int pgd_idx, pmd_idx; 135 unsigned long vaddr; 136 137 if (pmd_idx_kmap_begin == pmd_idx_kmap_end) 138 return 0; 139 140 vaddr = start; 141 pgd_idx = pgd_index(vaddr); 142 pmd_idx = pmd_index(vaddr); 143 144 for ( ; (pgd_idx < PTRS_PER_PGD) && (vaddr != end); pgd_idx++) { 145 for (; (pmd_idx < PTRS_PER_PMD) && (vaddr != end); 146 pmd_idx++) { 147 if ((vaddr >> PMD_SHIFT) >= pmd_idx_kmap_begin && 148 (vaddr >> PMD_SHIFT) <= pmd_idx_kmap_end) 149 count++; 150 vaddr += PMD_SIZE; 151 } 152 pmd_idx = 0; 153 } 154 #endif 155 return count; 156 } 157 158 static pte_t *__init page_table_kmap_check(pte_t *pte, pmd_t *pmd, 159 unsigned long vaddr, pte_t *lastpte, 160 void **adr) 161 { 162 #ifdef CONFIG_HIGHMEM 163 /* 164 * Something (early fixmap) may already have put a pte 165 * page here, which causes the page table allocation 166 * to become nonlinear. Attempt to fix it, and if it 167 * is still nonlinear then we have to bug. 168 */ 169 int pmd_idx_kmap_begin = fix_to_virt(FIX_KMAP_END) >> PMD_SHIFT; 170 int pmd_idx_kmap_end = fix_to_virt(FIX_KMAP_BEGIN) >> PMD_SHIFT; 171 172 if (pmd_idx_kmap_begin != pmd_idx_kmap_end 173 && (vaddr >> PMD_SHIFT) >= pmd_idx_kmap_begin 174 && (vaddr >> PMD_SHIFT) <= pmd_idx_kmap_end) { 175 pte_t *newpte; 176 int i; 177 178 BUG_ON(after_bootmem); 179 newpte = *adr; 180 for (i = 0; i < PTRS_PER_PTE; i++) 181 set_pte(newpte + i, pte[i]); 182 *adr = (void *)(((unsigned long)(*adr)) + PAGE_SIZE); 183 184 paravirt_alloc_pte(&init_mm, __pa(newpte) >> PAGE_SHIFT); 185 set_pmd(pmd, __pmd(__pa(newpte)|_PAGE_TABLE)); 186 BUG_ON(newpte != pte_offset_kernel(pmd, 0)); 187 __flush_tlb_all(); 188 189 paravirt_release_pte(__pa(pte) >> PAGE_SHIFT); 190 pte = newpte; 191 } 192 BUG_ON(vaddr < fix_to_virt(FIX_KMAP_BEGIN - 1) 193 && vaddr > fix_to_virt(FIX_KMAP_END) 194 && lastpte && lastpte + PTRS_PER_PTE != pte); 195 #endif 196 return pte; 197 } 198 199 /* 200 * This function initializes a certain range of kernel virtual memory 201 * with new bootmem page tables, everywhere page tables are missing in 202 * the given range. 203 * 204 * NOTE: The pagetables are allocated contiguous on the physical space 205 * so we can cache the place of the first one and move around without 206 * checking the pgd every time. 207 */ 208 static void __init 209 page_table_range_init(unsigned long start, unsigned long end, pgd_t *pgd_base) 210 { 211 int pgd_idx, pmd_idx; 212 unsigned long vaddr; 213 pgd_t *pgd; 214 pmd_t *pmd; 215 pte_t *pte = NULL; 216 unsigned long count = page_table_range_init_count(start, end); 217 void *adr = NULL; 218 219 if (count) 220 adr = alloc_low_pages(count); 221 222 vaddr = start; 223 pgd_idx = pgd_index(vaddr); 224 pmd_idx = pmd_index(vaddr); 225 pgd = pgd_base + pgd_idx; 226 227 for ( ; (pgd_idx < PTRS_PER_PGD) && (vaddr != end); pgd++, pgd_idx++) { 228 pmd = one_md_table_init(pgd); 229 pmd = pmd + pmd_index(vaddr); 230 for (; (pmd_idx < PTRS_PER_PMD) && (vaddr != end); 231 pmd++, pmd_idx++) { 232 pte = page_table_kmap_check(one_page_table_init(pmd), 233 pmd, vaddr, pte, &adr); 234 235 vaddr += PMD_SIZE; 236 } 237 pmd_idx = 0; 238 } 239 } 240 241 /* 242 * The <linux/kallsyms.h> already defines is_kernel_text, 243 * using '__' prefix not to get in conflict. 244 */ 245 static inline int __is_kernel_text(unsigned long addr) 246 { 247 if (addr >= (unsigned long)_text && addr <= (unsigned long)__init_end) 248 return 1; 249 return 0; 250 } 251 252 /* 253 * This maps the physical memory to kernel virtual address space, a total 254 * of max_low_pfn pages, by creating page tables starting from address 255 * PAGE_OFFSET: 256 */ 257 unsigned long __init 258 kernel_physical_mapping_init(unsigned long start, 259 unsigned long end, 260 unsigned long page_size_mask) 261 { 262 int use_pse = page_size_mask == (1<<PG_LEVEL_2M); 263 unsigned long last_map_addr = end; 264 unsigned long start_pfn, end_pfn; 265 pgd_t *pgd_base = swapper_pg_dir; 266 int pgd_idx, pmd_idx, pte_ofs; 267 unsigned long pfn; 268 pgd_t *pgd; 269 pmd_t *pmd; 270 pte_t *pte; 271 unsigned pages_2m, pages_4k; 272 int mapping_iter; 273 274 start_pfn = start >> PAGE_SHIFT; 275 end_pfn = end >> PAGE_SHIFT; 276 277 /* 278 * First iteration will setup identity mapping using large/small pages 279 * based on use_pse, with other attributes same as set by 280 * the early code in head_32.S 281 * 282 * Second iteration will setup the appropriate attributes (NX, GLOBAL..) 283 * as desired for the kernel identity mapping. 284 * 285 * This two pass mechanism conforms to the TLB app note which says: 286 * 287 * "Software should not write to a paging-structure entry in a way 288 * that would change, for any linear address, both the page size 289 * and either the page frame or attributes." 290 */ 291 mapping_iter = 1; 292 293 if (!boot_cpu_has(X86_FEATURE_PSE)) 294 use_pse = 0; 295 296 repeat: 297 pages_2m = pages_4k = 0; 298 pfn = start_pfn; 299 pgd_idx = pgd_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET); 300 pgd = pgd_base + pgd_idx; 301 for (; pgd_idx < PTRS_PER_PGD; pgd++, pgd_idx++) { 302 pmd = one_md_table_init(pgd); 303 304 if (pfn >= end_pfn) 305 continue; 306 #ifdef CONFIG_X86_PAE 307 pmd_idx = pmd_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET); 308 pmd += pmd_idx; 309 #else 310 pmd_idx = 0; 311 #endif 312 for (; pmd_idx < PTRS_PER_PMD && pfn < end_pfn; 313 pmd++, pmd_idx++) { 314 unsigned int addr = pfn * PAGE_SIZE + PAGE_OFFSET; 315 316 /* 317 * Map with big pages if possible, otherwise 318 * create normal page tables: 319 */ 320 if (use_pse) { 321 unsigned int addr2; 322 pgprot_t prot = PAGE_KERNEL_LARGE; 323 /* 324 * first pass will use the same initial 325 * identity mapping attribute + _PAGE_PSE. 326 */ 327 pgprot_t init_prot = 328 __pgprot(PTE_IDENT_ATTR | 329 _PAGE_PSE); 330 331 pfn &= PMD_MASK >> PAGE_SHIFT; 332 addr2 = (pfn + PTRS_PER_PTE-1) * PAGE_SIZE + 333 PAGE_OFFSET + PAGE_SIZE-1; 334 335 if (__is_kernel_text(addr) || 336 __is_kernel_text(addr2)) 337 prot = PAGE_KERNEL_LARGE_EXEC; 338 339 pages_2m++; 340 if (mapping_iter == 1) 341 set_pmd(pmd, pfn_pmd(pfn, init_prot)); 342 else 343 set_pmd(pmd, pfn_pmd(pfn, prot)); 344 345 pfn += PTRS_PER_PTE; 346 continue; 347 } 348 pte = one_page_table_init(pmd); 349 350 pte_ofs = pte_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET); 351 pte += pte_ofs; 352 for (; pte_ofs < PTRS_PER_PTE && pfn < end_pfn; 353 pte++, pfn++, pte_ofs++, addr += PAGE_SIZE) { 354 pgprot_t prot = PAGE_KERNEL; 355 /* 356 * first pass will use the same initial 357 * identity mapping attribute. 358 */ 359 pgprot_t init_prot = __pgprot(PTE_IDENT_ATTR); 360 361 if (__is_kernel_text(addr)) 362 prot = PAGE_KERNEL_EXEC; 363 364 pages_4k++; 365 if (mapping_iter == 1) { 366 set_pte(pte, pfn_pte(pfn, init_prot)); 367 last_map_addr = (pfn << PAGE_SHIFT) + PAGE_SIZE; 368 } else 369 set_pte(pte, pfn_pte(pfn, prot)); 370 } 371 } 372 } 373 if (mapping_iter == 1) { 374 /* 375 * update direct mapping page count only in the first 376 * iteration. 377 */ 378 update_page_count(PG_LEVEL_2M, pages_2m); 379 update_page_count(PG_LEVEL_4K, pages_4k); 380 381 /* 382 * local global flush tlb, which will flush the previous 383 * mappings present in both small and large page TLB's. 384 */ 385 __flush_tlb_all(); 386 387 /* 388 * Second iteration will set the actual desired PTE attributes. 389 */ 390 mapping_iter = 2; 391 goto repeat; 392 } 393 return last_map_addr; 394 } 395 396 pte_t *kmap_pte; 397 398 static inline pte_t *kmap_get_fixmap_pte(unsigned long vaddr) 399 { 400 pgd_t *pgd = pgd_offset_k(vaddr); 401 p4d_t *p4d = p4d_offset(pgd, vaddr); 402 pud_t *pud = pud_offset(p4d, vaddr); 403 pmd_t *pmd = pmd_offset(pud, vaddr); 404 return pte_offset_kernel(pmd, vaddr); 405 } 406 407 static void __init kmap_init(void) 408 { 409 unsigned long kmap_vstart; 410 411 /* 412 * Cache the first kmap pte: 413 */ 414 kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN); 415 kmap_pte = kmap_get_fixmap_pte(kmap_vstart); 416 } 417 418 #ifdef CONFIG_HIGHMEM 419 static void __init permanent_kmaps_init(pgd_t *pgd_base) 420 { 421 unsigned long vaddr; 422 pgd_t *pgd; 423 p4d_t *p4d; 424 pud_t *pud; 425 pmd_t *pmd; 426 pte_t *pte; 427 428 vaddr = PKMAP_BASE; 429 page_table_range_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, pgd_base); 430 431 pgd = swapper_pg_dir + pgd_index(vaddr); 432 p4d = p4d_offset(pgd, vaddr); 433 pud = pud_offset(p4d, vaddr); 434 pmd = pmd_offset(pud, vaddr); 435 pte = pte_offset_kernel(pmd, vaddr); 436 pkmap_page_table = pte; 437 } 438 439 void __init add_highpages_with_active_regions(int nid, 440 unsigned long start_pfn, unsigned long end_pfn) 441 { 442 phys_addr_t start, end; 443 u64 i; 444 445 for_each_free_mem_range(i, nid, MEMBLOCK_NONE, &start, &end, NULL) { 446 unsigned long pfn = clamp_t(unsigned long, PFN_UP(start), 447 start_pfn, end_pfn); 448 unsigned long e_pfn = clamp_t(unsigned long, PFN_DOWN(end), 449 start_pfn, end_pfn); 450 for ( ; pfn < e_pfn; pfn++) 451 if (pfn_valid(pfn)) 452 free_highmem_page(pfn_to_page(pfn)); 453 } 454 } 455 #else 456 static inline void permanent_kmaps_init(pgd_t *pgd_base) 457 { 458 } 459 #endif /* CONFIG_HIGHMEM */ 460 461 void __init sync_initial_page_table(void) 462 { 463 clone_pgd_range(initial_page_table + KERNEL_PGD_BOUNDARY, 464 swapper_pg_dir + KERNEL_PGD_BOUNDARY, 465 KERNEL_PGD_PTRS); 466 467 /* 468 * sync back low identity map too. It is used for example 469 * in the 32-bit EFI stub. 470 */ 471 clone_pgd_range(initial_page_table, 472 swapper_pg_dir + KERNEL_PGD_BOUNDARY, 473 min(KERNEL_PGD_PTRS, KERNEL_PGD_BOUNDARY)); 474 } 475 476 void __init native_pagetable_init(void) 477 { 478 unsigned long pfn, va; 479 pgd_t *pgd, *base = swapper_pg_dir; 480 p4d_t *p4d; 481 pud_t *pud; 482 pmd_t *pmd; 483 pte_t *pte; 484 485 /* 486 * Remove any mappings which extend past the end of physical 487 * memory from the boot time page table. 488 * In virtual address space, we should have at least two pages 489 * from VMALLOC_END to pkmap or fixmap according to VMALLOC_END 490 * definition. And max_low_pfn is set to VMALLOC_END physical 491 * address. If initial memory mapping is doing right job, we 492 * should have pte used near max_low_pfn or one pmd is not present. 493 */ 494 for (pfn = max_low_pfn; pfn < 1<<(32-PAGE_SHIFT); pfn++) { 495 va = PAGE_OFFSET + (pfn<<PAGE_SHIFT); 496 pgd = base + pgd_index(va); 497 if (!pgd_present(*pgd)) 498 break; 499 500 p4d = p4d_offset(pgd, va); 501 pud = pud_offset(p4d, va); 502 pmd = pmd_offset(pud, va); 503 if (!pmd_present(*pmd)) 504 break; 505 506 /* should not be large page here */ 507 if (pmd_large(*pmd)) { 508 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", 509 pfn, pmd, __pa(pmd)); 510 BUG_ON(1); 511 } 512 513 pte = pte_offset_kernel(pmd, va); 514 if (!pte_present(*pte)) 515 break; 516 517 printk(KERN_DEBUG "clearing pte for ram above max_low_pfn: pfn: %lx pmd: %p pmd phys: %lx pte: %p pte phys: %lx\n", 518 pfn, pmd, __pa(pmd), pte, __pa(pte)); 519 pte_clear(NULL, va, pte); 520 } 521 paravirt_alloc_pmd(&init_mm, __pa(base) >> PAGE_SHIFT); 522 paging_init(); 523 } 524 525 /* 526 * Build a proper pagetable for the kernel mappings. Up until this 527 * point, we've been running on some set of pagetables constructed by 528 * the boot process. 529 * 530 * If we're booting on native hardware, this will be a pagetable 531 * constructed in arch/x86/kernel/head_32.S. The root of the 532 * pagetable will be swapper_pg_dir. 533 * 534 * If we're booting paravirtualized under a hypervisor, then there are 535 * more options: we may already be running PAE, and the pagetable may 536 * or may not be based in swapper_pg_dir. In any case, 537 * paravirt_pagetable_init() will set up swapper_pg_dir 538 * appropriately for the rest of the initialization to work. 539 * 540 * In general, pagetable_init() assumes that the pagetable may already 541 * be partially populated, and so it avoids stomping on any existing 542 * mappings. 543 */ 544 void __init early_ioremap_page_table_range_init(void) 545 { 546 pgd_t *pgd_base = swapper_pg_dir; 547 unsigned long vaddr, end; 548 549 /* 550 * Fixed mappings, only the page table structure has to be 551 * created - mappings will be set by set_fixmap(): 552 */ 553 vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK; 554 end = (FIXADDR_TOP + PMD_SIZE - 1) & PMD_MASK; 555 page_table_range_init(vaddr, end, pgd_base); 556 early_ioremap_reset(); 557 } 558 559 static void __init pagetable_init(void) 560 { 561 pgd_t *pgd_base = swapper_pg_dir; 562 563 permanent_kmaps_init(pgd_base); 564 } 565 566 #define DEFAULT_PTE_MASK ~(_PAGE_NX | _PAGE_GLOBAL) 567 /* Bits supported by the hardware: */ 568 pteval_t __supported_pte_mask __read_mostly = DEFAULT_PTE_MASK; 569 /* Bits allowed in normal kernel mappings: */ 570 pteval_t __default_kernel_pte_mask __read_mostly = DEFAULT_PTE_MASK; 571 EXPORT_SYMBOL_GPL(__supported_pte_mask); 572 /* Used in PAGE_KERNEL_* macros which are reasonably used out-of-tree: */ 573 EXPORT_SYMBOL(__default_kernel_pte_mask); 574 575 /* user-defined highmem size */ 576 static unsigned int highmem_pages = -1; 577 578 /* 579 * highmem=size forces highmem to be exactly 'size' bytes. 580 * This works even on boxes that have no highmem otherwise. 581 * This also works to reduce highmem size on bigger boxes. 582 */ 583 static int __init parse_highmem(char *arg) 584 { 585 if (!arg) 586 return -EINVAL; 587 588 highmem_pages = memparse(arg, &arg) >> PAGE_SHIFT; 589 return 0; 590 } 591 early_param("highmem", parse_highmem); 592 593 #define MSG_HIGHMEM_TOO_BIG \ 594 "highmem size (%luMB) is bigger than pages available (%luMB)!\n" 595 596 #define MSG_LOWMEM_TOO_SMALL \ 597 "highmem size (%luMB) results in <64MB lowmem, ignoring it!\n" 598 /* 599 * All of RAM fits into lowmem - but if user wants highmem 600 * artificially via the highmem=x boot parameter then create 601 * it: 602 */ 603 static void __init lowmem_pfn_init(void) 604 { 605 /* max_low_pfn is 0, we already have early_res support */ 606 max_low_pfn = max_pfn; 607 608 if (highmem_pages == -1) 609 highmem_pages = 0; 610 #ifdef CONFIG_HIGHMEM 611 if (highmem_pages >= max_pfn) { 612 printk(KERN_ERR MSG_HIGHMEM_TOO_BIG, 613 pages_to_mb(highmem_pages), pages_to_mb(max_pfn)); 614 highmem_pages = 0; 615 } 616 if (highmem_pages) { 617 if (max_low_pfn - highmem_pages < 64*1024*1024/PAGE_SIZE) { 618 printk(KERN_ERR MSG_LOWMEM_TOO_SMALL, 619 pages_to_mb(highmem_pages)); 620 highmem_pages = 0; 621 } 622 max_low_pfn -= highmem_pages; 623 } 624 #else 625 if (highmem_pages) 626 printk(KERN_ERR "ignoring highmem size on non-highmem kernel!\n"); 627 #endif 628 } 629 630 #define MSG_HIGHMEM_TOO_SMALL \ 631 "only %luMB highmem pages available, ignoring highmem size of %luMB!\n" 632 633 #define MSG_HIGHMEM_TRIMMED \ 634 "Warning: only 4GB will be used. Use a HIGHMEM64G enabled kernel!\n" 635 /* 636 * We have more RAM than fits into lowmem - we try to put it into 637 * highmem, also taking the highmem=x boot parameter into account: 638 */ 639 static void __init highmem_pfn_init(void) 640 { 641 max_low_pfn = MAXMEM_PFN; 642 643 if (highmem_pages == -1) 644 highmem_pages = max_pfn - MAXMEM_PFN; 645 646 if (highmem_pages + MAXMEM_PFN < max_pfn) 647 max_pfn = MAXMEM_PFN + highmem_pages; 648 649 if (highmem_pages + MAXMEM_PFN > max_pfn) { 650 printk(KERN_WARNING MSG_HIGHMEM_TOO_SMALL, 651 pages_to_mb(max_pfn - MAXMEM_PFN), 652 pages_to_mb(highmem_pages)); 653 highmem_pages = 0; 654 } 655 #ifndef CONFIG_HIGHMEM 656 /* Maximum memory usable is what is directly addressable */ 657 printk(KERN_WARNING "Warning only %ldMB will be used.\n", MAXMEM>>20); 658 if (max_pfn > MAX_NONPAE_PFN) 659 printk(KERN_WARNING "Use a HIGHMEM64G enabled kernel.\n"); 660 else 661 printk(KERN_WARNING "Use a HIGHMEM enabled kernel.\n"); 662 max_pfn = MAXMEM_PFN; 663 #else /* !CONFIG_HIGHMEM */ 664 #ifndef CONFIG_HIGHMEM64G 665 if (max_pfn > MAX_NONPAE_PFN) { 666 max_pfn = MAX_NONPAE_PFN; 667 printk(KERN_WARNING MSG_HIGHMEM_TRIMMED); 668 } 669 #endif /* !CONFIG_HIGHMEM64G */ 670 #endif /* !CONFIG_HIGHMEM */ 671 } 672 673 /* 674 * Determine low and high memory ranges: 675 */ 676 void __init find_low_pfn_range(void) 677 { 678 /* it could update max_pfn */ 679 680 if (max_pfn <= MAXMEM_PFN) 681 lowmem_pfn_init(); 682 else 683 highmem_pfn_init(); 684 } 685 686 #ifndef CONFIG_NEED_MULTIPLE_NODES 687 void __init initmem_init(void) 688 { 689 #ifdef CONFIG_HIGHMEM 690 highstart_pfn = highend_pfn = max_pfn; 691 if (max_pfn > max_low_pfn) 692 highstart_pfn = max_low_pfn; 693 printk(KERN_NOTICE "%ldMB HIGHMEM available.\n", 694 pages_to_mb(highend_pfn - highstart_pfn)); 695 high_memory = (void *) __va(highstart_pfn * PAGE_SIZE - 1) + 1; 696 #else 697 high_memory = (void *) __va(max_low_pfn * PAGE_SIZE - 1) + 1; 698 #endif 699 700 memblock_set_node(0, PHYS_ADDR_MAX, &memblock.memory, 0); 701 sparse_memory_present_with_active_regions(0); 702 703 #ifdef CONFIG_FLATMEM 704 max_mapnr = IS_ENABLED(CONFIG_HIGHMEM) ? highend_pfn : max_low_pfn; 705 #endif 706 __vmalloc_start_set = true; 707 708 printk(KERN_NOTICE "%ldMB LOWMEM available.\n", 709 pages_to_mb(max_low_pfn)); 710 711 setup_bootmem_allocator(); 712 } 713 #endif /* !CONFIG_NEED_MULTIPLE_NODES */ 714 715 void __init setup_bootmem_allocator(void) 716 { 717 printk(KERN_INFO " mapped low ram: 0 - %08lx\n", 718 max_pfn_mapped<<PAGE_SHIFT); 719 printk(KERN_INFO " low ram: 0 - %08lx\n", max_low_pfn<<PAGE_SHIFT); 720 } 721 722 /* 723 * paging_init() sets up the page tables - note that the first 8MB are 724 * already mapped by head.S. 725 * 726 * This routines also unmaps the page at virtual kernel address 0, so 727 * that we can trap those pesky NULL-reference errors in the kernel. 728 */ 729 void __init paging_init(void) 730 { 731 pagetable_init(); 732 733 __flush_tlb_all(); 734 735 kmap_init(); 736 737 /* 738 * NOTE: at this point the bootmem allocator is fully available. 739 */ 740 olpc_dt_build_devicetree(); 741 sparse_memory_present_with_active_regions(MAX_NUMNODES); 742 sparse_init(); 743 zone_sizes_init(); 744 } 745 746 /* 747 * Test if the WP bit works in supervisor mode. It isn't supported on 386's 748 * and also on some strange 486's. All 586+'s are OK. This used to involve 749 * black magic jumps to work around some nasty CPU bugs, but fortunately the 750 * switch to using exceptions got rid of all that. 751 */ 752 static void __init test_wp_bit(void) 753 { 754 char z = 0; 755 756 printk(KERN_INFO "Checking if this processor honours the WP bit even in supervisor mode..."); 757 758 __set_fixmap(FIX_WP_TEST, __pa_symbol(empty_zero_page), PAGE_KERNEL_RO); 759 760 if (probe_kernel_write((char *)fix_to_virt(FIX_WP_TEST), &z, 1)) { 761 clear_fixmap(FIX_WP_TEST); 762 printk(KERN_CONT "Ok.\n"); 763 return; 764 } 765 766 printk(KERN_CONT "No.\n"); 767 panic("Linux doesn't support CPUs with broken WP."); 768 } 769 770 void __init mem_init(void) 771 { 772 pci_iommu_alloc(); 773 774 #ifdef CONFIG_FLATMEM 775 BUG_ON(!mem_map); 776 #endif 777 /* 778 * With CONFIG_DEBUG_PAGEALLOC initialization of highmem pages has to 779 * be done before memblock_free_all(). Memblock use free low memory for 780 * temporary data (see find_range_array()) and for this purpose can use 781 * pages that was already passed to the buddy allocator, hence marked as 782 * not accessible in the page tables when compiled with 783 * CONFIG_DEBUG_PAGEALLOC. Otherwise order of initialization is not 784 * important here. 785 */ 786 set_highmem_pages_init(); 787 788 /* this will put all low memory onto the freelists */ 789 memblock_free_all(); 790 791 after_bootmem = 1; 792 x86_init.hyper.init_after_bootmem(); 793 794 mem_init_print_info(NULL); 795 printk(KERN_INFO "virtual kernel memory layout:\n" 796 " fixmap : 0x%08lx - 0x%08lx (%4ld kB)\n" 797 " cpu_entry : 0x%08lx - 0x%08lx (%4ld kB)\n" 798 #ifdef CONFIG_HIGHMEM 799 " pkmap : 0x%08lx - 0x%08lx (%4ld kB)\n" 800 #endif 801 " vmalloc : 0x%08lx - 0x%08lx (%4ld MB)\n" 802 " lowmem : 0x%08lx - 0x%08lx (%4ld MB)\n" 803 " .init : 0x%08lx - 0x%08lx (%4ld kB)\n" 804 " .data : 0x%08lx - 0x%08lx (%4ld kB)\n" 805 " .text : 0x%08lx - 0x%08lx (%4ld kB)\n", 806 FIXADDR_START, FIXADDR_TOP, 807 (FIXADDR_TOP - FIXADDR_START) >> 10, 808 809 CPU_ENTRY_AREA_BASE, 810 CPU_ENTRY_AREA_BASE + CPU_ENTRY_AREA_MAP_SIZE, 811 CPU_ENTRY_AREA_MAP_SIZE >> 10, 812 813 #ifdef CONFIG_HIGHMEM 814 PKMAP_BASE, PKMAP_BASE+LAST_PKMAP*PAGE_SIZE, 815 (LAST_PKMAP*PAGE_SIZE) >> 10, 816 #endif 817 818 VMALLOC_START, VMALLOC_END, 819 (VMALLOC_END - VMALLOC_START) >> 20, 820 821 (unsigned long)__va(0), (unsigned long)high_memory, 822 ((unsigned long)high_memory - (unsigned long)__va(0)) >> 20, 823 824 (unsigned long)&__init_begin, (unsigned long)&__init_end, 825 ((unsigned long)&__init_end - 826 (unsigned long)&__init_begin) >> 10, 827 828 (unsigned long)&_etext, (unsigned long)&_edata, 829 ((unsigned long)&_edata - (unsigned long)&_etext) >> 10, 830 831 (unsigned long)&_text, (unsigned long)&_etext, 832 ((unsigned long)&_etext - (unsigned long)&_text) >> 10); 833 834 /* 835 * Check boundaries twice: Some fundamental inconsistencies can 836 * be detected at build time already. 837 */ 838 #define __FIXADDR_TOP (-PAGE_SIZE) 839 #ifdef CONFIG_HIGHMEM 840 BUILD_BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE > FIXADDR_START); 841 BUILD_BUG_ON(VMALLOC_END > PKMAP_BASE); 842 #endif 843 #define high_memory (-128UL << 20) 844 BUILD_BUG_ON(VMALLOC_START >= VMALLOC_END); 845 #undef high_memory 846 #undef __FIXADDR_TOP 847 848 #ifdef CONFIG_HIGHMEM 849 BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE > FIXADDR_START); 850 BUG_ON(VMALLOC_END > PKMAP_BASE); 851 #endif 852 BUG_ON(VMALLOC_START >= VMALLOC_END); 853 BUG_ON((unsigned long)high_memory > VMALLOC_START); 854 855 test_wp_bit(); 856 } 857 858 #ifdef CONFIG_MEMORY_HOTPLUG 859 int arch_add_memory(int nid, u64 start, u64 size, 860 struct mhp_restrictions *restrictions) 861 { 862 unsigned long start_pfn = start >> PAGE_SHIFT; 863 unsigned long nr_pages = size >> PAGE_SHIFT; 864 865 return __add_pages(nid, start_pfn, nr_pages, restrictions); 866 } 867 868 void arch_remove_memory(int nid, u64 start, u64 size, 869 struct vmem_altmap *altmap) 870 { 871 unsigned long start_pfn = start >> PAGE_SHIFT; 872 unsigned long nr_pages = size >> PAGE_SHIFT; 873 874 __remove_pages(start_pfn, nr_pages, altmap); 875 } 876 #endif 877 878 int kernel_set_to_readonly __read_mostly; 879 880 static void mark_nxdata_nx(void) 881 { 882 /* 883 * When this called, init has already been executed and released, 884 * so everything past _etext should be NX. 885 */ 886 unsigned long start = PFN_ALIGN(_etext); 887 /* 888 * This comes from __is_kernel_text upper limit. Also HPAGE where used: 889 */ 890 unsigned long size = (((unsigned long)__init_end + HPAGE_SIZE) & HPAGE_MASK) - start; 891 892 if (__supported_pte_mask & _PAGE_NX) 893 printk(KERN_INFO "NX-protecting the kernel data: %luk\n", size >> 10); 894 set_memory_nx(start, size >> PAGE_SHIFT); 895 } 896 897 void mark_rodata_ro(void) 898 { 899 unsigned long start = PFN_ALIGN(_text); 900 unsigned long size = (unsigned long)__end_rodata - start; 901 902 set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT); 903 pr_info("Write protecting kernel text and read-only data: %luk\n", 904 size >> 10); 905 906 kernel_set_to_readonly = 1; 907 908 #ifdef CONFIG_CPA_DEBUG 909 pr_info("Testing CPA: Reverting %lx-%lx\n", start, start + size); 910 set_pages_rw(virt_to_page(start), size >> PAGE_SHIFT); 911 912 pr_info("Testing CPA: write protecting again\n"); 913 set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT); 914 #endif 915 mark_nxdata_nx(); 916 if (__supported_pte_mask & _PAGE_NX) 917 debug_checkwx(); 918 } 919