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 pgprot_t prot) 262 { 263 int use_pse = page_size_mask == (1<<PG_LEVEL_2M); 264 unsigned long last_map_addr = end; 265 unsigned long start_pfn, end_pfn; 266 pgd_t *pgd_base = swapper_pg_dir; 267 int pgd_idx, pmd_idx, pte_ofs; 268 unsigned long pfn; 269 pgd_t *pgd; 270 pmd_t *pmd; 271 pte_t *pte; 272 unsigned pages_2m, pages_4k; 273 int mapping_iter; 274 275 start_pfn = start >> PAGE_SHIFT; 276 end_pfn = end >> PAGE_SHIFT; 277 278 /* 279 * First iteration will setup identity mapping using large/small pages 280 * based on use_pse, with other attributes same as set by 281 * the early code in head_32.S 282 * 283 * Second iteration will setup the appropriate attributes (NX, GLOBAL..) 284 * as desired for the kernel identity mapping. 285 * 286 * This two pass mechanism conforms to the TLB app note which says: 287 * 288 * "Software should not write to a paging-structure entry in a way 289 * that would change, for any linear address, both the page size 290 * and either the page frame or attributes." 291 */ 292 mapping_iter = 1; 293 294 if (!boot_cpu_has(X86_FEATURE_PSE)) 295 use_pse = 0; 296 297 repeat: 298 pages_2m = pages_4k = 0; 299 pfn = start_pfn; 300 pgd_idx = pgd_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET); 301 pgd = pgd_base + pgd_idx; 302 for (; pgd_idx < PTRS_PER_PGD; pgd++, pgd_idx++) { 303 pmd = one_md_table_init(pgd); 304 305 if (pfn >= end_pfn) 306 continue; 307 #ifdef CONFIG_X86_PAE 308 pmd_idx = pmd_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET); 309 pmd += pmd_idx; 310 #else 311 pmd_idx = 0; 312 #endif 313 for (; pmd_idx < PTRS_PER_PMD && pfn < end_pfn; 314 pmd++, pmd_idx++) { 315 unsigned int addr = pfn * PAGE_SIZE + PAGE_OFFSET; 316 317 /* 318 * Map with big pages if possible, otherwise 319 * create normal page tables: 320 */ 321 if (use_pse) { 322 unsigned int addr2; 323 pgprot_t prot = PAGE_KERNEL_LARGE; 324 /* 325 * first pass will use the same initial 326 * identity mapping attribute + _PAGE_PSE. 327 */ 328 pgprot_t init_prot = 329 __pgprot(PTE_IDENT_ATTR | 330 _PAGE_PSE); 331 332 pfn &= PMD_MASK >> PAGE_SHIFT; 333 addr2 = (pfn + PTRS_PER_PTE-1) * PAGE_SIZE + 334 PAGE_OFFSET + PAGE_SIZE-1; 335 336 if (__is_kernel_text(addr) || 337 __is_kernel_text(addr2)) 338 prot = PAGE_KERNEL_LARGE_EXEC; 339 340 pages_2m++; 341 if (mapping_iter == 1) 342 set_pmd(pmd, pfn_pmd(pfn, init_prot)); 343 else 344 set_pmd(pmd, pfn_pmd(pfn, prot)); 345 346 pfn += PTRS_PER_PTE; 347 continue; 348 } 349 pte = one_page_table_init(pmd); 350 351 pte_ofs = pte_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET); 352 pte += pte_ofs; 353 for (; pte_ofs < PTRS_PER_PTE && pfn < end_pfn; 354 pte++, pfn++, pte_ofs++, addr += PAGE_SIZE) { 355 pgprot_t prot = PAGE_KERNEL; 356 /* 357 * first pass will use the same initial 358 * identity mapping attribute. 359 */ 360 pgprot_t init_prot = __pgprot(PTE_IDENT_ATTR); 361 362 if (__is_kernel_text(addr)) 363 prot = PAGE_KERNEL_EXEC; 364 365 pages_4k++; 366 if (mapping_iter == 1) { 367 set_pte(pte, pfn_pte(pfn, init_prot)); 368 last_map_addr = (pfn << PAGE_SHIFT) + PAGE_SIZE; 369 } else 370 set_pte(pte, pfn_pte(pfn, prot)); 371 } 372 } 373 } 374 if (mapping_iter == 1) { 375 /* 376 * update direct mapping page count only in the first 377 * iteration. 378 */ 379 update_page_count(PG_LEVEL_2M, pages_2m); 380 update_page_count(PG_LEVEL_4K, pages_4k); 381 382 /* 383 * local global flush tlb, which will flush the previous 384 * mappings present in both small and large page TLB's. 385 */ 386 __flush_tlb_all(); 387 388 /* 389 * Second iteration will set the actual desired PTE attributes. 390 */ 391 mapping_iter = 2; 392 goto repeat; 393 } 394 return last_map_addr; 395 } 396 397 pte_t *kmap_pte; 398 399 static inline pte_t *kmap_get_fixmap_pte(unsigned long vaddr) 400 { 401 pgd_t *pgd = pgd_offset_k(vaddr); 402 p4d_t *p4d = p4d_offset(pgd, vaddr); 403 pud_t *pud = pud_offset(p4d, vaddr); 404 pmd_t *pmd = pmd_offset(pud, vaddr); 405 return pte_offset_kernel(pmd, vaddr); 406 } 407 408 static void __init kmap_init(void) 409 { 410 unsigned long kmap_vstart; 411 412 /* 413 * Cache the first kmap pte: 414 */ 415 kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN); 416 kmap_pte = kmap_get_fixmap_pte(kmap_vstart); 417 } 418 419 #ifdef CONFIG_HIGHMEM 420 static void __init permanent_kmaps_init(pgd_t *pgd_base) 421 { 422 unsigned long vaddr; 423 pgd_t *pgd; 424 p4d_t *p4d; 425 pud_t *pud; 426 pmd_t *pmd; 427 pte_t *pte; 428 429 vaddr = PKMAP_BASE; 430 page_table_range_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, pgd_base); 431 432 pgd = swapper_pg_dir + pgd_index(vaddr); 433 p4d = p4d_offset(pgd, vaddr); 434 pud = pud_offset(p4d, vaddr); 435 pmd = pmd_offset(pud, vaddr); 436 pte = pte_offset_kernel(pmd, vaddr); 437 pkmap_page_table = pte; 438 } 439 440 void __init add_highpages_with_active_regions(int nid, 441 unsigned long start_pfn, unsigned long end_pfn) 442 { 443 phys_addr_t start, end; 444 u64 i; 445 446 for_each_free_mem_range(i, nid, MEMBLOCK_NONE, &start, &end, NULL) { 447 unsigned long pfn = clamp_t(unsigned long, PFN_UP(start), 448 start_pfn, end_pfn); 449 unsigned long e_pfn = clamp_t(unsigned long, PFN_DOWN(end), 450 start_pfn, end_pfn); 451 for ( ; pfn < e_pfn; pfn++) 452 if (pfn_valid(pfn)) 453 free_highmem_page(pfn_to_page(pfn)); 454 } 455 } 456 #else 457 static inline void permanent_kmaps_init(pgd_t *pgd_base) 458 { 459 } 460 #endif /* CONFIG_HIGHMEM */ 461 462 void __init sync_initial_page_table(void) 463 { 464 clone_pgd_range(initial_page_table + KERNEL_PGD_BOUNDARY, 465 swapper_pg_dir + KERNEL_PGD_BOUNDARY, 466 KERNEL_PGD_PTRS); 467 468 /* 469 * sync back low identity map too. It is used for example 470 * in the 32-bit EFI stub. 471 */ 472 clone_pgd_range(initial_page_table, 473 swapper_pg_dir + KERNEL_PGD_BOUNDARY, 474 min(KERNEL_PGD_PTRS, KERNEL_PGD_BOUNDARY)); 475 } 476 477 void __init native_pagetable_init(void) 478 { 479 unsigned long pfn, va; 480 pgd_t *pgd, *base = swapper_pg_dir; 481 p4d_t *p4d; 482 pud_t *pud; 483 pmd_t *pmd; 484 pte_t *pte; 485 486 /* 487 * Remove any mappings which extend past the end of physical 488 * memory from the boot time page table. 489 * In virtual address space, we should have at least two pages 490 * from VMALLOC_END to pkmap or fixmap according to VMALLOC_END 491 * definition. And max_low_pfn is set to VMALLOC_END physical 492 * address. If initial memory mapping is doing right job, we 493 * should have pte used near max_low_pfn or one pmd is not present. 494 */ 495 for (pfn = max_low_pfn; pfn < 1<<(32-PAGE_SHIFT); pfn++) { 496 va = PAGE_OFFSET + (pfn<<PAGE_SHIFT); 497 pgd = base + pgd_index(va); 498 if (!pgd_present(*pgd)) 499 break; 500 501 p4d = p4d_offset(pgd, va); 502 pud = pud_offset(p4d, va); 503 pmd = pmd_offset(pud, va); 504 if (!pmd_present(*pmd)) 505 break; 506 507 /* should not be large page here */ 508 if (pmd_large(*pmd)) { 509 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", 510 pfn, pmd, __pa(pmd)); 511 BUG_ON(1); 512 } 513 514 pte = pte_offset_kernel(pmd, va); 515 if (!pte_present(*pte)) 516 break; 517 518 printk(KERN_DEBUG "clearing pte for ram above max_low_pfn: pfn: %lx pmd: %p pmd phys: %lx pte: %p pte phys: %lx\n", 519 pfn, pmd, __pa(pmd), pte, __pa(pte)); 520 pte_clear(NULL, va, pte); 521 } 522 paravirt_alloc_pmd(&init_mm, __pa(base) >> PAGE_SHIFT); 523 paging_init(); 524 } 525 526 /* 527 * Build a proper pagetable for the kernel mappings. Up until this 528 * point, we've been running on some set of pagetables constructed by 529 * the boot process. 530 * 531 * If we're booting on native hardware, this will be a pagetable 532 * constructed in arch/x86/kernel/head_32.S. The root of the 533 * pagetable will be swapper_pg_dir. 534 * 535 * If we're booting paravirtualized under a hypervisor, then there are 536 * more options: we may already be running PAE, and the pagetable may 537 * or may not be based in swapper_pg_dir. In any case, 538 * paravirt_pagetable_init() will set up swapper_pg_dir 539 * appropriately for the rest of the initialization to work. 540 * 541 * In general, pagetable_init() assumes that the pagetable may already 542 * be partially populated, and so it avoids stomping on any existing 543 * mappings. 544 */ 545 void __init early_ioremap_page_table_range_init(void) 546 { 547 pgd_t *pgd_base = swapper_pg_dir; 548 unsigned long vaddr, end; 549 550 /* 551 * Fixed mappings, only the page table structure has to be 552 * created - mappings will be set by set_fixmap(): 553 */ 554 vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK; 555 end = (FIXADDR_TOP + PMD_SIZE - 1) & PMD_MASK; 556 page_table_range_init(vaddr, end, pgd_base); 557 early_ioremap_reset(); 558 } 559 560 static void __init pagetable_init(void) 561 { 562 pgd_t *pgd_base = swapper_pg_dir; 563 564 permanent_kmaps_init(pgd_base); 565 } 566 567 #define DEFAULT_PTE_MASK ~(_PAGE_NX | _PAGE_GLOBAL) 568 /* Bits supported by the hardware: */ 569 pteval_t __supported_pte_mask __read_mostly = DEFAULT_PTE_MASK; 570 /* Bits allowed in normal kernel mappings: */ 571 pteval_t __default_kernel_pte_mask __read_mostly = DEFAULT_PTE_MASK; 572 EXPORT_SYMBOL_GPL(__supported_pte_mask); 573 /* Used in PAGE_KERNEL_* macros which are reasonably used out-of-tree: */ 574 EXPORT_SYMBOL(__default_kernel_pte_mask); 575 576 /* user-defined highmem size */ 577 static unsigned int highmem_pages = -1; 578 579 /* 580 * highmem=size forces highmem to be exactly 'size' bytes. 581 * This works even on boxes that have no highmem otherwise. 582 * This also works to reduce highmem size on bigger boxes. 583 */ 584 static int __init parse_highmem(char *arg) 585 { 586 if (!arg) 587 return -EINVAL; 588 589 highmem_pages = memparse(arg, &arg) >> PAGE_SHIFT; 590 return 0; 591 } 592 early_param("highmem", parse_highmem); 593 594 #define MSG_HIGHMEM_TOO_BIG \ 595 "highmem size (%luMB) is bigger than pages available (%luMB)!\n" 596 597 #define MSG_LOWMEM_TOO_SMALL \ 598 "highmem size (%luMB) results in <64MB lowmem, ignoring it!\n" 599 /* 600 * All of RAM fits into lowmem - but if user wants highmem 601 * artificially via the highmem=x boot parameter then create 602 * it: 603 */ 604 static void __init lowmem_pfn_init(void) 605 { 606 /* max_low_pfn is 0, we already have early_res support */ 607 max_low_pfn = max_pfn; 608 609 if (highmem_pages == -1) 610 highmem_pages = 0; 611 #ifdef CONFIG_HIGHMEM 612 if (highmem_pages >= max_pfn) { 613 printk(KERN_ERR MSG_HIGHMEM_TOO_BIG, 614 pages_to_mb(highmem_pages), pages_to_mb(max_pfn)); 615 highmem_pages = 0; 616 } 617 if (highmem_pages) { 618 if (max_low_pfn - highmem_pages < 64*1024*1024/PAGE_SIZE) { 619 printk(KERN_ERR MSG_LOWMEM_TOO_SMALL, 620 pages_to_mb(highmem_pages)); 621 highmem_pages = 0; 622 } 623 max_low_pfn -= highmem_pages; 624 } 625 #else 626 if (highmem_pages) 627 printk(KERN_ERR "ignoring highmem size on non-highmem kernel!\n"); 628 #endif 629 } 630 631 #define MSG_HIGHMEM_TOO_SMALL \ 632 "only %luMB highmem pages available, ignoring highmem size of %luMB!\n" 633 634 #define MSG_HIGHMEM_TRIMMED \ 635 "Warning: only 4GB will be used. Use a HIGHMEM64G enabled kernel!\n" 636 /* 637 * We have more RAM than fits into lowmem - we try to put it into 638 * highmem, also taking the highmem=x boot parameter into account: 639 */ 640 static void __init highmem_pfn_init(void) 641 { 642 max_low_pfn = MAXMEM_PFN; 643 644 if (highmem_pages == -1) 645 highmem_pages = max_pfn - MAXMEM_PFN; 646 647 if (highmem_pages + MAXMEM_PFN < max_pfn) 648 max_pfn = MAXMEM_PFN + highmem_pages; 649 650 if (highmem_pages + MAXMEM_PFN > max_pfn) { 651 printk(KERN_WARNING MSG_HIGHMEM_TOO_SMALL, 652 pages_to_mb(max_pfn - MAXMEM_PFN), 653 pages_to_mb(highmem_pages)); 654 highmem_pages = 0; 655 } 656 #ifndef CONFIG_HIGHMEM 657 /* Maximum memory usable is what is directly addressable */ 658 printk(KERN_WARNING "Warning only %ldMB will be used.\n", MAXMEM>>20); 659 if (max_pfn > MAX_NONPAE_PFN) 660 printk(KERN_WARNING "Use a HIGHMEM64G enabled kernel.\n"); 661 else 662 printk(KERN_WARNING "Use a HIGHMEM enabled kernel.\n"); 663 max_pfn = MAXMEM_PFN; 664 #else /* !CONFIG_HIGHMEM */ 665 #ifndef CONFIG_HIGHMEM64G 666 if (max_pfn > MAX_NONPAE_PFN) { 667 max_pfn = MAX_NONPAE_PFN; 668 printk(KERN_WARNING MSG_HIGHMEM_TRIMMED); 669 } 670 #endif /* !CONFIG_HIGHMEM64G */ 671 #endif /* !CONFIG_HIGHMEM */ 672 } 673 674 /* 675 * Determine low and high memory ranges: 676 */ 677 void __init find_low_pfn_range(void) 678 { 679 /* it could update max_pfn */ 680 681 if (max_pfn <= MAXMEM_PFN) 682 lowmem_pfn_init(); 683 else 684 highmem_pfn_init(); 685 } 686 687 #ifndef CONFIG_NEED_MULTIPLE_NODES 688 void __init initmem_init(void) 689 { 690 #ifdef CONFIG_HIGHMEM 691 highstart_pfn = highend_pfn = max_pfn; 692 if (max_pfn > max_low_pfn) 693 highstart_pfn = max_low_pfn; 694 printk(KERN_NOTICE "%ldMB HIGHMEM available.\n", 695 pages_to_mb(highend_pfn - highstart_pfn)); 696 high_memory = (void *) __va(highstart_pfn * PAGE_SIZE - 1) + 1; 697 #else 698 high_memory = (void *) __va(max_low_pfn * PAGE_SIZE - 1) + 1; 699 #endif 700 701 memblock_set_node(0, PHYS_ADDR_MAX, &memblock.memory, 0); 702 sparse_memory_present_with_active_regions(0); 703 704 #ifdef CONFIG_FLATMEM 705 max_mapnr = IS_ENABLED(CONFIG_HIGHMEM) ? highend_pfn : max_low_pfn; 706 #endif 707 __vmalloc_start_set = true; 708 709 printk(KERN_NOTICE "%ldMB LOWMEM available.\n", 710 pages_to_mb(max_low_pfn)); 711 712 setup_bootmem_allocator(); 713 } 714 #endif /* !CONFIG_NEED_MULTIPLE_NODES */ 715 716 void __init setup_bootmem_allocator(void) 717 { 718 printk(KERN_INFO " mapped low ram: 0 - %08lx\n", 719 max_pfn_mapped<<PAGE_SHIFT); 720 printk(KERN_INFO " low ram: 0 - %08lx\n", max_low_pfn<<PAGE_SHIFT); 721 } 722 723 /* 724 * paging_init() sets up the page tables - note that the first 8MB are 725 * already mapped by head.S. 726 * 727 * This routines also unmaps the page at virtual kernel address 0, so 728 * that we can trap those pesky NULL-reference errors in the kernel. 729 */ 730 void __init paging_init(void) 731 { 732 pagetable_init(); 733 734 __flush_tlb_all(); 735 736 kmap_init(); 737 738 /* 739 * NOTE: at this point the bootmem allocator is fully available. 740 */ 741 olpc_dt_build_devicetree(); 742 sparse_memory_present_with_active_regions(MAX_NUMNODES); 743 sparse_init(); 744 zone_sizes_init(); 745 } 746 747 /* 748 * Test if the WP bit works in supervisor mode. It isn't supported on 386's 749 * and also on some strange 486's. All 586+'s are OK. This used to involve 750 * black magic jumps to work around some nasty CPU bugs, but fortunately the 751 * switch to using exceptions got rid of all that. 752 */ 753 static void __init test_wp_bit(void) 754 { 755 char z = 0; 756 757 printk(KERN_INFO "Checking if this processor honours the WP bit even in supervisor mode..."); 758 759 __set_fixmap(FIX_WP_TEST, __pa_symbol(empty_zero_page), PAGE_KERNEL_RO); 760 761 if (probe_kernel_write((char *)fix_to_virt(FIX_WP_TEST), &z, 1)) { 762 clear_fixmap(FIX_WP_TEST); 763 printk(KERN_CONT "Ok.\n"); 764 return; 765 } 766 767 printk(KERN_CONT "No.\n"); 768 panic("Linux doesn't support CPUs with broken WP."); 769 } 770 771 void __init mem_init(void) 772 { 773 pci_iommu_alloc(); 774 775 #ifdef CONFIG_FLATMEM 776 BUG_ON(!mem_map); 777 #endif 778 /* 779 * With CONFIG_DEBUG_PAGEALLOC initialization of highmem pages has to 780 * be done before memblock_free_all(). Memblock use free low memory for 781 * temporary data (see find_range_array()) and for this purpose can use 782 * pages that was already passed to the buddy allocator, hence marked as 783 * not accessible in the page tables when compiled with 784 * CONFIG_DEBUG_PAGEALLOC. Otherwise order of initialization is not 785 * important here. 786 */ 787 set_highmem_pages_init(); 788 789 /* this will put all low memory onto the freelists */ 790 memblock_free_all(); 791 792 after_bootmem = 1; 793 x86_init.hyper.init_after_bootmem(); 794 795 mem_init_print_info(NULL); 796 797 /* 798 * Check boundaries twice: Some fundamental inconsistencies can 799 * be detected at build time already. 800 */ 801 #define __FIXADDR_TOP (-PAGE_SIZE) 802 #ifdef CONFIG_HIGHMEM 803 BUILD_BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE > FIXADDR_START); 804 BUILD_BUG_ON(VMALLOC_END > PKMAP_BASE); 805 #endif 806 #define high_memory (-128UL << 20) 807 BUILD_BUG_ON(VMALLOC_START >= VMALLOC_END); 808 #undef high_memory 809 #undef __FIXADDR_TOP 810 811 #ifdef CONFIG_HIGHMEM 812 BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE > FIXADDR_START); 813 BUG_ON(VMALLOC_END > PKMAP_BASE); 814 #endif 815 BUG_ON(VMALLOC_START >= VMALLOC_END); 816 BUG_ON((unsigned long)high_memory > VMALLOC_START); 817 818 test_wp_bit(); 819 } 820 821 #ifdef CONFIG_MEMORY_HOTPLUG 822 int arch_add_memory(int nid, u64 start, u64 size, 823 struct mhp_params *params) 824 { 825 unsigned long start_pfn = start >> PAGE_SHIFT; 826 unsigned long nr_pages = size >> PAGE_SHIFT; 827 int ret; 828 829 /* 830 * The page tables were already mapped at boot so if the caller 831 * requests a different mapping type then we must change all the 832 * pages with __set_memory_prot(). 833 */ 834 if (params->pgprot.pgprot != PAGE_KERNEL.pgprot) { 835 ret = __set_memory_prot(start, nr_pages, params->pgprot); 836 if (ret) 837 return ret; 838 } 839 840 return __add_pages(nid, start_pfn, nr_pages, params); 841 } 842 843 void arch_remove_memory(int nid, u64 start, u64 size, 844 struct vmem_altmap *altmap) 845 { 846 unsigned long start_pfn = start >> PAGE_SHIFT; 847 unsigned long nr_pages = size >> PAGE_SHIFT; 848 849 __remove_pages(start_pfn, nr_pages, altmap); 850 } 851 #endif 852 853 int kernel_set_to_readonly __read_mostly; 854 855 static void mark_nxdata_nx(void) 856 { 857 /* 858 * When this called, init has already been executed and released, 859 * so everything past _etext should be NX. 860 */ 861 unsigned long start = PFN_ALIGN(_etext); 862 /* 863 * This comes from __is_kernel_text upper limit. Also HPAGE where used: 864 */ 865 unsigned long size = (((unsigned long)__init_end + HPAGE_SIZE) & HPAGE_MASK) - start; 866 867 if (__supported_pte_mask & _PAGE_NX) 868 printk(KERN_INFO "NX-protecting the kernel data: %luk\n", size >> 10); 869 set_memory_nx(start, size >> PAGE_SHIFT); 870 } 871 872 void mark_rodata_ro(void) 873 { 874 unsigned long start = PFN_ALIGN(_text); 875 unsigned long size = (unsigned long)__end_rodata - start; 876 877 set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT); 878 pr_info("Write protecting kernel text and read-only data: %luk\n", 879 size >> 10); 880 881 kernel_set_to_readonly = 1; 882 883 #ifdef CONFIG_CPA_DEBUG 884 pr_info("Testing CPA: Reverting %lx-%lx\n", start, start + size); 885 set_pages_rw(virt_to_page(start), size >> PAGE_SHIFT); 886 887 pr_info("Testing CPA: write protecting again\n"); 888 set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT); 889 #endif 890 mark_nxdata_nx(); 891 if (__supported_pte_mask & _PAGE_NX) 892 debug_checkwx(); 893 } 894