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/dma.h> 39 #include <asm/fixmap.h> 40 #include <asm/e820/api.h> 41 #include <asm/apic.h> 42 #include <asm/bugs.h> 43 #include <asm/tlb.h> 44 #include <asm/tlbflush.h> 45 #include <asm/olpc_ofw.h> 46 #include <asm/pgalloc.h> 47 #include <asm/sections.h> 48 #include <asm/paravirt.h> 49 #include <asm/setup.h> 50 #include <asm/set_memory.h> 51 #include <asm/page_types.h> 52 #include <asm/cpu_entry_area.h> 53 #include <asm/init.h> 54 #include <asm/pgtable_areas.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 /* 241 * The <linux/kallsyms.h> already defines is_kernel_text, 242 * using '__' prefix not to get in conflict. 243 */ 244 static inline int __is_kernel_text(unsigned long addr) 245 { 246 if (addr >= (unsigned long)_text && addr <= (unsigned long)__init_end) 247 return 1; 248 return 0; 249 } 250 251 /* 252 * This maps the physical memory to kernel virtual address space, a total 253 * of max_low_pfn pages, by creating page tables starting from address 254 * PAGE_OFFSET: 255 */ 256 unsigned long __init 257 kernel_physical_mapping_init(unsigned long start, 258 unsigned long end, 259 unsigned long page_size_mask, 260 pgprot_t prot) 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 void __init kmap_init(void) 399 { 400 unsigned long kmap_vstart; 401 402 /* 403 * Cache the first kmap pte: 404 */ 405 kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN); 406 kmap_pte = virt_to_kpte(kmap_vstart); 407 } 408 409 #ifdef CONFIG_HIGHMEM 410 static void __init permanent_kmaps_init(pgd_t *pgd_base) 411 { 412 unsigned long vaddr = PKMAP_BASE; 413 414 page_table_range_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, pgd_base); 415 416 pkmap_page_table = virt_to_kpte(vaddr); 417 } 418 419 void __init add_highpages_with_active_regions(int nid, 420 unsigned long start_pfn, unsigned long end_pfn) 421 { 422 phys_addr_t start, end; 423 u64 i; 424 425 for_each_free_mem_range(i, nid, MEMBLOCK_NONE, &start, &end, NULL) { 426 unsigned long pfn = clamp_t(unsigned long, PFN_UP(start), 427 start_pfn, end_pfn); 428 unsigned long e_pfn = clamp_t(unsigned long, PFN_DOWN(end), 429 start_pfn, end_pfn); 430 for ( ; pfn < e_pfn; pfn++) 431 if (pfn_valid(pfn)) 432 free_highmem_page(pfn_to_page(pfn)); 433 } 434 } 435 #else 436 static inline void permanent_kmaps_init(pgd_t *pgd_base) 437 { 438 } 439 #endif /* CONFIG_HIGHMEM */ 440 441 void __init sync_initial_page_table(void) 442 { 443 clone_pgd_range(initial_page_table + KERNEL_PGD_BOUNDARY, 444 swapper_pg_dir + KERNEL_PGD_BOUNDARY, 445 KERNEL_PGD_PTRS); 446 447 /* 448 * sync back low identity map too. It is used for example 449 * in the 32-bit EFI stub. 450 */ 451 clone_pgd_range(initial_page_table, 452 swapper_pg_dir + KERNEL_PGD_BOUNDARY, 453 min(KERNEL_PGD_PTRS, KERNEL_PGD_BOUNDARY)); 454 } 455 456 void __init native_pagetable_init(void) 457 { 458 unsigned long pfn, va; 459 pgd_t *pgd, *base = swapper_pg_dir; 460 p4d_t *p4d; 461 pud_t *pud; 462 pmd_t *pmd; 463 pte_t *pte; 464 465 /* 466 * Remove any mappings which extend past the end of physical 467 * memory from the boot time page table. 468 * In virtual address space, we should have at least two pages 469 * from VMALLOC_END to pkmap or fixmap according to VMALLOC_END 470 * definition. And max_low_pfn is set to VMALLOC_END physical 471 * address. If initial memory mapping is doing right job, we 472 * should have pte used near max_low_pfn or one pmd is not present. 473 */ 474 for (pfn = max_low_pfn; pfn < 1<<(32-PAGE_SHIFT); pfn++) { 475 va = PAGE_OFFSET + (pfn<<PAGE_SHIFT); 476 pgd = base + pgd_index(va); 477 if (!pgd_present(*pgd)) 478 break; 479 480 p4d = p4d_offset(pgd, va); 481 pud = pud_offset(p4d, va); 482 pmd = pmd_offset(pud, va); 483 if (!pmd_present(*pmd)) 484 break; 485 486 /* should not be large page here */ 487 if (pmd_large(*pmd)) { 488 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", 489 pfn, pmd, __pa(pmd)); 490 BUG_ON(1); 491 } 492 493 pte = pte_offset_kernel(pmd, va); 494 if (!pte_present(*pte)) 495 break; 496 497 printk(KERN_DEBUG "clearing pte for ram above max_low_pfn: pfn: %lx pmd: %p pmd phys: %lx pte: %p pte phys: %lx\n", 498 pfn, pmd, __pa(pmd), pte, __pa(pte)); 499 pte_clear(NULL, va, pte); 500 } 501 paravirt_alloc_pmd(&init_mm, __pa(base) >> PAGE_SHIFT); 502 paging_init(); 503 } 504 505 /* 506 * Build a proper pagetable for the kernel mappings. Up until this 507 * point, we've been running on some set of pagetables constructed by 508 * the boot process. 509 * 510 * If we're booting on native hardware, this will be a pagetable 511 * constructed in arch/x86/kernel/head_32.S. The root of the 512 * pagetable will be swapper_pg_dir. 513 * 514 * If we're booting paravirtualized under a hypervisor, then there are 515 * more options: we may already be running PAE, and the pagetable may 516 * or may not be based in swapper_pg_dir. In any case, 517 * paravirt_pagetable_init() will set up swapper_pg_dir 518 * appropriately for the rest of the initialization to work. 519 * 520 * In general, pagetable_init() assumes that the pagetable may already 521 * be partially populated, and so it avoids stomping on any existing 522 * mappings. 523 */ 524 void __init early_ioremap_page_table_range_init(void) 525 { 526 pgd_t *pgd_base = swapper_pg_dir; 527 unsigned long vaddr, end; 528 529 /* 530 * Fixed mappings, only the page table structure has to be 531 * created - mappings will be set by set_fixmap(): 532 */ 533 vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK; 534 end = (FIXADDR_TOP + PMD_SIZE - 1) & PMD_MASK; 535 page_table_range_init(vaddr, end, pgd_base); 536 early_ioremap_reset(); 537 } 538 539 static void __init pagetable_init(void) 540 { 541 pgd_t *pgd_base = swapper_pg_dir; 542 543 permanent_kmaps_init(pgd_base); 544 } 545 546 #define DEFAULT_PTE_MASK ~(_PAGE_NX | _PAGE_GLOBAL) 547 /* Bits supported by the hardware: */ 548 pteval_t __supported_pte_mask __read_mostly = DEFAULT_PTE_MASK; 549 /* Bits allowed in normal kernel mappings: */ 550 pteval_t __default_kernel_pte_mask __read_mostly = DEFAULT_PTE_MASK; 551 EXPORT_SYMBOL_GPL(__supported_pte_mask); 552 /* Used in PAGE_KERNEL_* macros which are reasonably used out-of-tree: */ 553 EXPORT_SYMBOL(__default_kernel_pte_mask); 554 555 /* user-defined highmem size */ 556 static unsigned int highmem_pages = -1; 557 558 /* 559 * highmem=size forces highmem to be exactly 'size' bytes. 560 * This works even on boxes that have no highmem otherwise. 561 * This also works to reduce highmem size on bigger boxes. 562 */ 563 static int __init parse_highmem(char *arg) 564 { 565 if (!arg) 566 return -EINVAL; 567 568 highmem_pages = memparse(arg, &arg) >> PAGE_SHIFT; 569 return 0; 570 } 571 early_param("highmem", parse_highmem); 572 573 #define MSG_HIGHMEM_TOO_BIG \ 574 "highmem size (%luMB) is bigger than pages available (%luMB)!\n" 575 576 #define MSG_LOWMEM_TOO_SMALL \ 577 "highmem size (%luMB) results in <64MB lowmem, ignoring it!\n" 578 /* 579 * All of RAM fits into lowmem - but if user wants highmem 580 * artificially via the highmem=x boot parameter then create 581 * it: 582 */ 583 static void __init lowmem_pfn_init(void) 584 { 585 /* max_low_pfn is 0, we already have early_res support */ 586 max_low_pfn = max_pfn; 587 588 if (highmem_pages == -1) 589 highmem_pages = 0; 590 #ifdef CONFIG_HIGHMEM 591 if (highmem_pages >= max_pfn) { 592 printk(KERN_ERR MSG_HIGHMEM_TOO_BIG, 593 pages_to_mb(highmem_pages), pages_to_mb(max_pfn)); 594 highmem_pages = 0; 595 } 596 if (highmem_pages) { 597 if (max_low_pfn - highmem_pages < 64*1024*1024/PAGE_SIZE) { 598 printk(KERN_ERR MSG_LOWMEM_TOO_SMALL, 599 pages_to_mb(highmem_pages)); 600 highmem_pages = 0; 601 } 602 max_low_pfn -= highmem_pages; 603 } 604 #else 605 if (highmem_pages) 606 printk(KERN_ERR "ignoring highmem size on non-highmem kernel!\n"); 607 #endif 608 } 609 610 #define MSG_HIGHMEM_TOO_SMALL \ 611 "only %luMB highmem pages available, ignoring highmem size of %luMB!\n" 612 613 #define MSG_HIGHMEM_TRIMMED \ 614 "Warning: only 4GB will be used. Use a HIGHMEM64G enabled kernel!\n" 615 /* 616 * We have more RAM than fits into lowmem - we try to put it into 617 * highmem, also taking the highmem=x boot parameter into account: 618 */ 619 static void __init highmem_pfn_init(void) 620 { 621 max_low_pfn = MAXMEM_PFN; 622 623 if (highmem_pages == -1) 624 highmem_pages = max_pfn - MAXMEM_PFN; 625 626 if (highmem_pages + MAXMEM_PFN < max_pfn) 627 max_pfn = MAXMEM_PFN + highmem_pages; 628 629 if (highmem_pages + MAXMEM_PFN > max_pfn) { 630 printk(KERN_WARNING MSG_HIGHMEM_TOO_SMALL, 631 pages_to_mb(max_pfn - MAXMEM_PFN), 632 pages_to_mb(highmem_pages)); 633 highmem_pages = 0; 634 } 635 #ifndef CONFIG_HIGHMEM 636 /* Maximum memory usable is what is directly addressable */ 637 printk(KERN_WARNING "Warning only %ldMB will be used.\n", MAXMEM>>20); 638 if (max_pfn > MAX_NONPAE_PFN) 639 printk(KERN_WARNING "Use a HIGHMEM64G enabled kernel.\n"); 640 else 641 printk(KERN_WARNING "Use a HIGHMEM enabled kernel.\n"); 642 max_pfn = MAXMEM_PFN; 643 #else /* !CONFIG_HIGHMEM */ 644 #ifndef CONFIG_HIGHMEM64G 645 if (max_pfn > MAX_NONPAE_PFN) { 646 max_pfn = MAX_NONPAE_PFN; 647 printk(KERN_WARNING MSG_HIGHMEM_TRIMMED); 648 } 649 #endif /* !CONFIG_HIGHMEM64G */ 650 #endif /* !CONFIG_HIGHMEM */ 651 } 652 653 /* 654 * Determine low and high memory ranges: 655 */ 656 void __init find_low_pfn_range(void) 657 { 658 /* it could update max_pfn */ 659 660 if (max_pfn <= MAXMEM_PFN) 661 lowmem_pfn_init(); 662 else 663 highmem_pfn_init(); 664 } 665 666 #ifndef CONFIG_NEED_MULTIPLE_NODES 667 void __init initmem_init(void) 668 { 669 #ifdef CONFIG_HIGHMEM 670 highstart_pfn = highend_pfn = max_pfn; 671 if (max_pfn > max_low_pfn) 672 highstart_pfn = max_low_pfn; 673 printk(KERN_NOTICE "%ldMB HIGHMEM available.\n", 674 pages_to_mb(highend_pfn - highstart_pfn)); 675 high_memory = (void *) __va(highstart_pfn * PAGE_SIZE - 1) + 1; 676 #else 677 high_memory = (void *) __va(max_low_pfn * PAGE_SIZE - 1) + 1; 678 #endif 679 680 memblock_set_node(0, PHYS_ADDR_MAX, &memblock.memory, 0); 681 sparse_memory_present_with_active_regions(0); 682 683 #ifdef CONFIG_FLATMEM 684 max_mapnr = IS_ENABLED(CONFIG_HIGHMEM) ? highend_pfn : max_low_pfn; 685 #endif 686 __vmalloc_start_set = true; 687 688 printk(KERN_NOTICE "%ldMB LOWMEM available.\n", 689 pages_to_mb(max_low_pfn)); 690 691 setup_bootmem_allocator(); 692 } 693 #endif /* !CONFIG_NEED_MULTIPLE_NODES */ 694 695 void __init setup_bootmem_allocator(void) 696 { 697 printk(KERN_INFO " mapped low ram: 0 - %08lx\n", 698 max_pfn_mapped<<PAGE_SHIFT); 699 printk(KERN_INFO " low ram: 0 - %08lx\n", max_low_pfn<<PAGE_SHIFT); 700 } 701 702 /* 703 * paging_init() sets up the page tables - note that the first 8MB are 704 * already mapped by head.S. 705 * 706 * This routines also unmaps the page at virtual kernel address 0, so 707 * that we can trap those pesky NULL-reference errors in the kernel. 708 */ 709 void __init paging_init(void) 710 { 711 pagetable_init(); 712 713 __flush_tlb_all(); 714 715 kmap_init(); 716 717 /* 718 * NOTE: at this point the bootmem allocator is fully available. 719 */ 720 olpc_dt_build_devicetree(); 721 sparse_memory_present_with_active_regions(MAX_NUMNODES); 722 sparse_init(); 723 zone_sizes_init(); 724 } 725 726 /* 727 * Test if the WP bit works in supervisor mode. It isn't supported on 386's 728 * and also on some strange 486's. All 586+'s are OK. This used to involve 729 * black magic jumps to work around some nasty CPU bugs, but fortunately the 730 * switch to using exceptions got rid of all that. 731 */ 732 static void __init test_wp_bit(void) 733 { 734 char z = 0; 735 736 printk(KERN_INFO "Checking if this processor honours the WP bit even in supervisor mode..."); 737 738 __set_fixmap(FIX_WP_TEST, __pa_symbol(empty_zero_page), PAGE_KERNEL_RO); 739 740 if (probe_kernel_write((char *)fix_to_virt(FIX_WP_TEST), &z, 1)) { 741 clear_fixmap(FIX_WP_TEST); 742 printk(KERN_CONT "Ok.\n"); 743 return; 744 } 745 746 printk(KERN_CONT "No.\n"); 747 panic("Linux doesn't support CPUs with broken WP."); 748 } 749 750 void __init mem_init(void) 751 { 752 pci_iommu_alloc(); 753 754 #ifdef CONFIG_FLATMEM 755 BUG_ON(!mem_map); 756 #endif 757 /* 758 * With CONFIG_DEBUG_PAGEALLOC initialization of highmem pages has to 759 * be done before memblock_free_all(). Memblock use free low memory for 760 * temporary data (see find_range_array()) and for this purpose can use 761 * pages that was already passed to the buddy allocator, hence marked as 762 * not accessible in the page tables when compiled with 763 * CONFIG_DEBUG_PAGEALLOC. Otherwise order of initialization is not 764 * important here. 765 */ 766 set_highmem_pages_init(); 767 768 /* this will put all low memory onto the freelists */ 769 memblock_free_all(); 770 771 after_bootmem = 1; 772 x86_init.hyper.init_after_bootmem(); 773 774 mem_init_print_info(NULL); 775 776 /* 777 * Check boundaries twice: Some fundamental inconsistencies can 778 * be detected at build time already. 779 */ 780 #define __FIXADDR_TOP (-PAGE_SIZE) 781 #ifdef CONFIG_HIGHMEM 782 BUILD_BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE > FIXADDR_START); 783 BUILD_BUG_ON(VMALLOC_END > PKMAP_BASE); 784 #endif 785 #define high_memory (-128UL << 20) 786 BUILD_BUG_ON(VMALLOC_START >= VMALLOC_END); 787 #undef high_memory 788 #undef __FIXADDR_TOP 789 790 #ifdef CONFIG_HIGHMEM 791 BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE > FIXADDR_START); 792 BUG_ON(VMALLOC_END > PKMAP_BASE); 793 #endif 794 BUG_ON(VMALLOC_START >= VMALLOC_END); 795 BUG_ON((unsigned long)high_memory > VMALLOC_START); 796 797 test_wp_bit(); 798 } 799 800 #ifdef CONFIG_MEMORY_HOTPLUG 801 int arch_add_memory(int nid, u64 start, u64 size, 802 struct mhp_params *params) 803 { 804 unsigned long start_pfn = start >> PAGE_SHIFT; 805 unsigned long nr_pages = size >> PAGE_SHIFT; 806 int ret; 807 808 /* 809 * The page tables were already mapped at boot so if the caller 810 * requests a different mapping type then we must change all the 811 * pages with __set_memory_prot(). 812 */ 813 if (params->pgprot.pgprot != PAGE_KERNEL.pgprot) { 814 ret = __set_memory_prot(start, nr_pages, params->pgprot); 815 if (ret) 816 return ret; 817 } 818 819 return __add_pages(nid, start_pfn, nr_pages, params); 820 } 821 822 void arch_remove_memory(int nid, u64 start, u64 size, 823 struct vmem_altmap *altmap) 824 { 825 unsigned long start_pfn = start >> PAGE_SHIFT; 826 unsigned long nr_pages = size >> PAGE_SHIFT; 827 828 __remove_pages(start_pfn, nr_pages, altmap); 829 } 830 #endif 831 832 int kernel_set_to_readonly __read_mostly; 833 834 static void mark_nxdata_nx(void) 835 { 836 /* 837 * When this called, init has already been executed and released, 838 * so everything past _etext should be NX. 839 */ 840 unsigned long start = PFN_ALIGN(_etext); 841 /* 842 * This comes from __is_kernel_text upper limit. Also HPAGE where used: 843 */ 844 unsigned long size = (((unsigned long)__init_end + HPAGE_SIZE) & HPAGE_MASK) - start; 845 846 if (__supported_pte_mask & _PAGE_NX) 847 printk(KERN_INFO "NX-protecting the kernel data: %luk\n", size >> 10); 848 set_memory_nx(start, size >> PAGE_SHIFT); 849 } 850 851 void mark_rodata_ro(void) 852 { 853 unsigned long start = PFN_ALIGN(_text); 854 unsigned long size = (unsigned long)__end_rodata - start; 855 856 set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT); 857 pr_info("Write protecting kernel text and read-only data: %luk\n", 858 size >> 10); 859 860 kernel_set_to_readonly = 1; 861 862 #ifdef CONFIG_CPA_DEBUG 863 pr_info("Testing CPA: Reverting %lx-%lx\n", start, start + size); 864 set_pages_rw(virt_to_page(start), size >> PAGE_SHIFT); 865 866 pr_info("Testing CPA: write protecting again\n"); 867 set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT); 868 #endif 869 mark_nxdata_nx(); 870 if (__supported_pte_mask & _PAGE_NX) 871 debug_checkwx(); 872 } 873