1 /* 2 * 3 * Copyright (C) 1995 Linus Torvalds 4 * 5 * Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999 6 */ 7 8 #include <linux/module.h> 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/bootmem.h> 28 #include <linux/memblock.h> 29 #include <linux/proc_fs.h> 30 #include <linux/memory_hotplug.h> 31 #include <linux/initrd.h> 32 #include <linux/cpumask.h> 33 #include <linux/gfp.h> 34 35 #include <asm/asm.h> 36 #include <asm/bios_ebda.h> 37 #include <asm/processor.h> 38 #include <asm/uaccess.h> 39 #include <asm/pgtable.h> 40 #include <asm/dma.h> 41 #include <asm/fixmap.h> 42 #include <asm/e820.h> 43 #include <asm/apic.h> 44 #include <asm/bugs.h> 45 #include <asm/tlb.h> 46 #include <asm/tlbflush.h> 47 #include <asm/olpc_ofw.h> 48 #include <asm/pgalloc.h> 49 #include <asm/sections.h> 50 #include <asm/paravirt.h> 51 #include <asm/setup.h> 52 #include <asm/cacheflush.h> 53 #include <asm/page_types.h> 54 #include <asm/init.h> 55 56 #include "mm_internal.h" 57 58 unsigned long highstart_pfn, highend_pfn; 59 60 static noinline int do_test_wp_bit(void); 61 62 bool __read_mostly __vmalloc_start_set = false; 63 64 /* 65 * Creates a middle page table and puts a pointer to it in the 66 * given global directory entry. This only returns the gd entry 67 * in non-PAE compilation mode, since the middle layer is folded. 68 */ 69 static pmd_t * __init one_md_table_init(pgd_t *pgd) 70 { 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 pud = pud_offset(pgd, 0); 80 BUG_ON(pmd_table != pmd_offset(pud, 0)); 81 82 return pmd_table; 83 } 84 #endif 85 pud = pud_offset(pgd, 0); 86 pmd_table = pmd_offset(pud, 0); 87 88 return pmd_table; 89 } 90 91 /* 92 * Create a page table and place a pointer to it in a middle page 93 * directory entry: 94 */ 95 static pte_t * __init one_page_table_init(pmd_t *pmd) 96 { 97 if (!(pmd_val(*pmd) & _PAGE_PRESENT)) { 98 pte_t *page_table = (pte_t *)alloc_low_page(); 99 100 paravirt_alloc_pte(&init_mm, __pa(page_table) >> PAGE_SHIFT); 101 set_pmd(pmd, __pmd(__pa(page_table) | _PAGE_TABLE)); 102 BUG_ON(page_table != pte_offset_kernel(pmd, 0)); 103 } 104 105 return pte_offset_kernel(pmd, 0); 106 } 107 108 pmd_t * __init populate_extra_pmd(unsigned long vaddr) 109 { 110 int pgd_idx = pgd_index(vaddr); 111 int pmd_idx = pmd_index(vaddr); 112 113 return one_md_table_init(swapper_pg_dir + pgd_idx) + pmd_idx; 114 } 115 116 pte_t * __init populate_extra_pte(unsigned long vaddr) 117 { 118 int pte_idx = pte_index(vaddr); 119 pmd_t *pmd; 120 121 pmd = populate_extra_pmd(vaddr); 122 return one_page_table_init(pmd) + pte_idx; 123 } 124 125 static unsigned long __init 126 page_table_range_init_count(unsigned long start, unsigned long end) 127 { 128 unsigned long count = 0; 129 #ifdef CONFIG_HIGHMEM 130 int pmd_idx_kmap_begin = fix_to_virt(FIX_KMAP_END) >> PMD_SHIFT; 131 int pmd_idx_kmap_end = fix_to_virt(FIX_KMAP_BEGIN) >> PMD_SHIFT; 132 int pgd_idx, pmd_idx; 133 unsigned long vaddr; 134 135 if (pmd_idx_kmap_begin == pmd_idx_kmap_end) 136 return 0; 137 138 vaddr = start; 139 pgd_idx = pgd_index(vaddr); 140 141 for ( ; (pgd_idx < PTRS_PER_PGD) && (vaddr != end); pgd_idx++) { 142 for (; (pmd_idx < PTRS_PER_PMD) && (vaddr != end); 143 pmd_idx++) { 144 if ((vaddr >> PMD_SHIFT) >= pmd_idx_kmap_begin && 145 (vaddr >> PMD_SHIFT) <= pmd_idx_kmap_end) 146 count++; 147 vaddr += PMD_SIZE; 148 } 149 pmd_idx = 0; 150 } 151 #endif 152 return count; 153 } 154 155 static pte_t *__init page_table_kmap_check(pte_t *pte, pmd_t *pmd, 156 unsigned long vaddr, pte_t *lastpte, 157 void **adr) 158 { 159 #ifdef CONFIG_HIGHMEM 160 /* 161 * Something (early fixmap) may already have put a pte 162 * page here, which causes the page table allocation 163 * to become nonlinear. Attempt to fix it, and if it 164 * is still nonlinear then we have to bug. 165 */ 166 int pmd_idx_kmap_begin = fix_to_virt(FIX_KMAP_END) >> PMD_SHIFT; 167 int pmd_idx_kmap_end = fix_to_virt(FIX_KMAP_BEGIN) >> PMD_SHIFT; 168 169 if (pmd_idx_kmap_begin != pmd_idx_kmap_end 170 && (vaddr >> PMD_SHIFT) >= pmd_idx_kmap_begin 171 && (vaddr >> PMD_SHIFT) <= pmd_idx_kmap_end) { 172 pte_t *newpte; 173 int i; 174 175 BUG_ON(after_bootmem); 176 newpte = *adr; 177 for (i = 0; i < PTRS_PER_PTE; i++) 178 set_pte(newpte + i, pte[i]); 179 *adr = (void *)(((unsigned long)(*adr)) + PAGE_SIZE); 180 181 paravirt_alloc_pte(&init_mm, __pa(newpte) >> PAGE_SHIFT); 182 set_pmd(pmd, __pmd(__pa(newpte)|_PAGE_TABLE)); 183 BUG_ON(newpte != pte_offset_kernel(pmd, 0)); 184 __flush_tlb_all(); 185 186 paravirt_release_pte(__pa(pte) >> PAGE_SHIFT); 187 pte = newpte; 188 } 189 BUG_ON(vaddr < fix_to_virt(FIX_KMAP_BEGIN - 1) 190 && vaddr > fix_to_virt(FIX_KMAP_END) 191 && lastpte && lastpte + PTRS_PER_PTE != pte); 192 #endif 193 return pte; 194 } 195 196 /* 197 * This function initializes a certain range of kernel virtual memory 198 * with new bootmem page tables, everywhere page tables are missing in 199 * the given range. 200 * 201 * NOTE: The pagetables are allocated contiguous on the physical space 202 * so we can cache the place of the first one and move around without 203 * checking the pgd every time. 204 */ 205 static void __init 206 page_table_range_init(unsigned long start, unsigned long end, pgd_t *pgd_base) 207 { 208 int pgd_idx, pmd_idx; 209 unsigned long vaddr; 210 pgd_t *pgd; 211 pmd_t *pmd; 212 pte_t *pte = NULL; 213 unsigned long count = page_table_range_init_count(start, end); 214 void *adr = NULL; 215 216 if (count) 217 adr = alloc_low_pages(count); 218 219 vaddr = start; 220 pgd_idx = pgd_index(vaddr); 221 pmd_idx = pmd_index(vaddr); 222 pgd = pgd_base + pgd_idx; 223 224 for ( ; (pgd_idx < PTRS_PER_PGD) && (vaddr != end); pgd++, pgd_idx++) { 225 pmd = one_md_table_init(pgd); 226 pmd = pmd + pmd_index(vaddr); 227 for (; (pmd_idx < PTRS_PER_PMD) && (vaddr != end); 228 pmd++, pmd_idx++) { 229 pte = page_table_kmap_check(one_page_table_init(pmd), 230 pmd, vaddr, pte, &adr); 231 232 vaddr += PMD_SIZE; 233 } 234 pmd_idx = 0; 235 } 236 } 237 238 static inline int is_kernel_text(unsigned long addr) 239 { 240 if (addr >= (unsigned long)_text && addr <= (unsigned long)__init_end) 241 return 1; 242 return 0; 243 } 244 245 /* 246 * This maps the physical memory to kernel virtual address space, a total 247 * of max_low_pfn pages, by creating page tables starting from address 248 * PAGE_OFFSET: 249 */ 250 unsigned long __init 251 kernel_physical_mapping_init(unsigned long start, 252 unsigned long end, 253 unsigned long page_size_mask) 254 { 255 int use_pse = page_size_mask == (1<<PG_LEVEL_2M); 256 unsigned long last_map_addr = end; 257 unsigned long start_pfn, end_pfn; 258 pgd_t *pgd_base = swapper_pg_dir; 259 int pgd_idx, pmd_idx, pte_ofs; 260 unsigned long pfn; 261 pgd_t *pgd; 262 pmd_t *pmd; 263 pte_t *pte; 264 unsigned pages_2m, pages_4k; 265 int mapping_iter; 266 267 start_pfn = start >> PAGE_SHIFT; 268 end_pfn = end >> PAGE_SHIFT; 269 270 /* 271 * First iteration will setup identity mapping using large/small pages 272 * based on use_pse, with other attributes same as set by 273 * the early code in head_32.S 274 * 275 * Second iteration will setup the appropriate attributes (NX, GLOBAL..) 276 * as desired for the kernel identity mapping. 277 * 278 * This two pass mechanism conforms to the TLB app note which says: 279 * 280 * "Software should not write to a paging-structure entry in a way 281 * that would change, for any linear address, both the page size 282 * and either the page frame or attributes." 283 */ 284 mapping_iter = 1; 285 286 if (!cpu_has_pse) 287 use_pse = 0; 288 289 repeat: 290 pages_2m = pages_4k = 0; 291 pfn = start_pfn; 292 pgd_idx = pgd_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET); 293 pgd = pgd_base + pgd_idx; 294 for (; pgd_idx < PTRS_PER_PGD; pgd++, pgd_idx++) { 295 pmd = one_md_table_init(pgd); 296 297 if (pfn >= end_pfn) 298 continue; 299 #ifdef CONFIG_X86_PAE 300 pmd_idx = pmd_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET); 301 pmd += pmd_idx; 302 #else 303 pmd_idx = 0; 304 #endif 305 for (; pmd_idx < PTRS_PER_PMD && pfn < end_pfn; 306 pmd++, pmd_idx++) { 307 unsigned int addr = pfn * PAGE_SIZE + PAGE_OFFSET; 308 309 /* 310 * Map with big pages if possible, otherwise 311 * create normal page tables: 312 */ 313 if (use_pse) { 314 unsigned int addr2; 315 pgprot_t prot = PAGE_KERNEL_LARGE; 316 /* 317 * first pass will use the same initial 318 * identity mapping attribute + _PAGE_PSE. 319 */ 320 pgprot_t init_prot = 321 __pgprot(PTE_IDENT_ATTR | 322 _PAGE_PSE); 323 324 pfn &= PMD_MASK >> PAGE_SHIFT; 325 addr2 = (pfn + PTRS_PER_PTE-1) * PAGE_SIZE + 326 PAGE_OFFSET + PAGE_SIZE-1; 327 328 if (is_kernel_text(addr) || 329 is_kernel_text(addr2)) 330 prot = PAGE_KERNEL_LARGE_EXEC; 331 332 pages_2m++; 333 if (mapping_iter == 1) 334 set_pmd(pmd, pfn_pmd(pfn, init_prot)); 335 else 336 set_pmd(pmd, pfn_pmd(pfn, prot)); 337 338 pfn += PTRS_PER_PTE; 339 continue; 340 } 341 pte = one_page_table_init(pmd); 342 343 pte_ofs = pte_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET); 344 pte += pte_ofs; 345 for (; pte_ofs < PTRS_PER_PTE && pfn < end_pfn; 346 pte++, pfn++, pte_ofs++, addr += PAGE_SIZE) { 347 pgprot_t prot = PAGE_KERNEL; 348 /* 349 * first pass will use the same initial 350 * identity mapping attribute. 351 */ 352 pgprot_t init_prot = __pgprot(PTE_IDENT_ATTR); 353 354 if (is_kernel_text(addr)) 355 prot = PAGE_KERNEL_EXEC; 356 357 pages_4k++; 358 if (mapping_iter == 1) { 359 set_pte(pte, pfn_pte(pfn, init_prot)); 360 last_map_addr = (pfn << PAGE_SHIFT) + PAGE_SIZE; 361 } else 362 set_pte(pte, pfn_pte(pfn, prot)); 363 } 364 } 365 } 366 if (mapping_iter == 1) { 367 /* 368 * update direct mapping page count only in the first 369 * iteration. 370 */ 371 update_page_count(PG_LEVEL_2M, pages_2m); 372 update_page_count(PG_LEVEL_4K, pages_4k); 373 374 /* 375 * local global flush tlb, which will flush the previous 376 * mappings present in both small and large page TLB's. 377 */ 378 __flush_tlb_all(); 379 380 /* 381 * Second iteration will set the actual desired PTE attributes. 382 */ 383 mapping_iter = 2; 384 goto repeat; 385 } 386 return last_map_addr; 387 } 388 389 pte_t *kmap_pte; 390 pgprot_t kmap_prot; 391 392 static inline pte_t *kmap_get_fixmap_pte(unsigned long vaddr) 393 { 394 return pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr), 395 vaddr), vaddr), vaddr); 396 } 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 = kmap_get_fixmap_pte(kmap_vstart); 407 408 kmap_prot = PAGE_KERNEL; 409 } 410 411 #ifdef CONFIG_HIGHMEM 412 static void __init permanent_kmaps_init(pgd_t *pgd_base) 413 { 414 unsigned long vaddr; 415 pgd_t *pgd; 416 pud_t *pud; 417 pmd_t *pmd; 418 pte_t *pte; 419 420 vaddr = PKMAP_BASE; 421 page_table_range_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, pgd_base); 422 423 pgd = swapper_pg_dir + pgd_index(vaddr); 424 pud = pud_offset(pgd, vaddr); 425 pmd = pmd_offset(pud, vaddr); 426 pte = pte_offset_kernel(pmd, vaddr); 427 pkmap_page_table = pte; 428 } 429 430 void __init add_highpages_with_active_regions(int nid, 431 unsigned long start_pfn, unsigned long end_pfn) 432 { 433 phys_addr_t start, end; 434 u64 i; 435 436 for_each_free_mem_range(i, nid, &start, &end, NULL) { 437 unsigned long pfn = clamp_t(unsigned long, PFN_UP(start), 438 start_pfn, end_pfn); 439 unsigned long e_pfn = clamp_t(unsigned long, PFN_DOWN(end), 440 start_pfn, end_pfn); 441 for ( ; pfn < e_pfn; pfn++) 442 if (pfn_valid(pfn)) 443 free_highmem_page(pfn_to_page(pfn)); 444 } 445 } 446 #else 447 static inline void permanent_kmaps_init(pgd_t *pgd_base) 448 { 449 } 450 #endif /* CONFIG_HIGHMEM */ 451 452 void __init native_pagetable_init(void) 453 { 454 unsigned long pfn, va; 455 pgd_t *pgd, *base = swapper_pg_dir; 456 pud_t *pud; 457 pmd_t *pmd; 458 pte_t *pte; 459 460 /* 461 * Remove any mappings which extend past the end of physical 462 * memory from the boot time page table. 463 * In virtual address space, we should have at least two pages 464 * from VMALLOC_END to pkmap or fixmap according to VMALLOC_END 465 * definition. And max_low_pfn is set to VMALLOC_END physical 466 * address. If initial memory mapping is doing right job, we 467 * should have pte used near max_low_pfn or one pmd is not present. 468 */ 469 for (pfn = max_low_pfn; pfn < 1<<(32-PAGE_SHIFT); pfn++) { 470 va = PAGE_OFFSET + (pfn<<PAGE_SHIFT); 471 pgd = base + pgd_index(va); 472 if (!pgd_present(*pgd)) 473 break; 474 475 pud = pud_offset(pgd, va); 476 pmd = pmd_offset(pud, va); 477 if (!pmd_present(*pmd)) 478 break; 479 480 /* should not be large page here */ 481 if (pmd_large(*pmd)) { 482 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", 483 pfn, pmd, __pa(pmd)); 484 BUG_ON(1); 485 } 486 487 pte = pte_offset_kernel(pmd, va); 488 if (!pte_present(*pte)) 489 break; 490 491 printk(KERN_DEBUG "clearing pte for ram above max_low_pfn: pfn: %lx pmd: %p pmd phys: %lx pte: %p pte phys: %lx\n", 492 pfn, pmd, __pa(pmd), pte, __pa(pte)); 493 pte_clear(NULL, va, pte); 494 } 495 paravirt_alloc_pmd(&init_mm, __pa(base) >> PAGE_SHIFT); 496 paging_init(); 497 } 498 499 /* 500 * Build a proper pagetable for the kernel mappings. Up until this 501 * point, we've been running on some set of pagetables constructed by 502 * the boot process. 503 * 504 * If we're booting on native hardware, this will be a pagetable 505 * constructed in arch/x86/kernel/head_32.S. The root of the 506 * pagetable will be swapper_pg_dir. 507 * 508 * If we're booting paravirtualized under a hypervisor, then there are 509 * more options: we may already be running PAE, and the pagetable may 510 * or may not be based in swapper_pg_dir. In any case, 511 * paravirt_pagetable_init() will set up swapper_pg_dir 512 * appropriately for the rest of the initialization to work. 513 * 514 * In general, pagetable_init() assumes that the pagetable may already 515 * be partially populated, and so it avoids stomping on any existing 516 * mappings. 517 */ 518 void __init early_ioremap_page_table_range_init(void) 519 { 520 pgd_t *pgd_base = swapper_pg_dir; 521 unsigned long vaddr, end; 522 523 /* 524 * Fixed mappings, only the page table structure has to be 525 * created - mappings will be set by set_fixmap(): 526 */ 527 vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK; 528 end = (FIXADDR_TOP + PMD_SIZE - 1) & PMD_MASK; 529 page_table_range_init(vaddr, end, pgd_base); 530 early_ioremap_reset(); 531 } 532 533 static void __init pagetable_init(void) 534 { 535 pgd_t *pgd_base = swapper_pg_dir; 536 537 permanent_kmaps_init(pgd_base); 538 } 539 540 pteval_t __supported_pte_mask __read_mostly = ~(_PAGE_NX | _PAGE_GLOBAL | _PAGE_IOMAP); 541 EXPORT_SYMBOL_GPL(__supported_pte_mask); 542 543 /* user-defined highmem size */ 544 static unsigned int highmem_pages = -1; 545 546 /* 547 * highmem=size forces highmem to be exactly 'size' bytes. 548 * This works even on boxes that have no highmem otherwise. 549 * This also works to reduce highmem size on bigger boxes. 550 */ 551 static int __init parse_highmem(char *arg) 552 { 553 if (!arg) 554 return -EINVAL; 555 556 highmem_pages = memparse(arg, &arg) >> PAGE_SHIFT; 557 return 0; 558 } 559 early_param("highmem", parse_highmem); 560 561 #define MSG_HIGHMEM_TOO_BIG \ 562 "highmem size (%luMB) is bigger than pages available (%luMB)!\n" 563 564 #define MSG_LOWMEM_TOO_SMALL \ 565 "highmem size (%luMB) results in <64MB lowmem, ignoring it!\n" 566 /* 567 * All of RAM fits into lowmem - but if user wants highmem 568 * artificially via the highmem=x boot parameter then create 569 * it: 570 */ 571 static void __init lowmem_pfn_init(void) 572 { 573 /* max_low_pfn is 0, we already have early_res support */ 574 max_low_pfn = max_pfn; 575 576 if (highmem_pages == -1) 577 highmem_pages = 0; 578 #ifdef CONFIG_HIGHMEM 579 if (highmem_pages >= max_pfn) { 580 printk(KERN_ERR MSG_HIGHMEM_TOO_BIG, 581 pages_to_mb(highmem_pages), pages_to_mb(max_pfn)); 582 highmem_pages = 0; 583 } 584 if (highmem_pages) { 585 if (max_low_pfn - highmem_pages < 64*1024*1024/PAGE_SIZE) { 586 printk(KERN_ERR MSG_LOWMEM_TOO_SMALL, 587 pages_to_mb(highmem_pages)); 588 highmem_pages = 0; 589 } 590 max_low_pfn -= highmem_pages; 591 } 592 #else 593 if (highmem_pages) 594 printk(KERN_ERR "ignoring highmem size on non-highmem kernel!\n"); 595 #endif 596 } 597 598 #define MSG_HIGHMEM_TOO_SMALL \ 599 "only %luMB highmem pages available, ignoring highmem size of %luMB!\n" 600 601 #define MSG_HIGHMEM_TRIMMED \ 602 "Warning: only 4GB will be used. Use a HIGHMEM64G enabled kernel!\n" 603 /* 604 * We have more RAM than fits into lowmem - we try to put it into 605 * highmem, also taking the highmem=x boot parameter into account: 606 */ 607 static void __init highmem_pfn_init(void) 608 { 609 max_low_pfn = MAXMEM_PFN; 610 611 if (highmem_pages == -1) 612 highmem_pages = max_pfn - MAXMEM_PFN; 613 614 if (highmem_pages + MAXMEM_PFN < max_pfn) 615 max_pfn = MAXMEM_PFN + highmem_pages; 616 617 if (highmem_pages + MAXMEM_PFN > max_pfn) { 618 printk(KERN_WARNING MSG_HIGHMEM_TOO_SMALL, 619 pages_to_mb(max_pfn - MAXMEM_PFN), 620 pages_to_mb(highmem_pages)); 621 highmem_pages = 0; 622 } 623 #ifndef CONFIG_HIGHMEM 624 /* Maximum memory usable is what is directly addressable */ 625 printk(KERN_WARNING "Warning only %ldMB will be used.\n", MAXMEM>>20); 626 if (max_pfn > MAX_NONPAE_PFN) 627 printk(KERN_WARNING "Use a HIGHMEM64G enabled kernel.\n"); 628 else 629 printk(KERN_WARNING "Use a HIGHMEM enabled kernel.\n"); 630 max_pfn = MAXMEM_PFN; 631 #else /* !CONFIG_HIGHMEM */ 632 #ifndef CONFIG_HIGHMEM64G 633 if (max_pfn > MAX_NONPAE_PFN) { 634 max_pfn = MAX_NONPAE_PFN; 635 printk(KERN_WARNING MSG_HIGHMEM_TRIMMED); 636 } 637 #endif /* !CONFIG_HIGHMEM64G */ 638 #endif /* !CONFIG_HIGHMEM */ 639 } 640 641 /* 642 * Determine low and high memory ranges: 643 */ 644 void __init find_low_pfn_range(void) 645 { 646 /* it could update max_pfn */ 647 648 if (max_pfn <= MAXMEM_PFN) 649 lowmem_pfn_init(); 650 else 651 highmem_pfn_init(); 652 } 653 654 #ifndef CONFIG_NEED_MULTIPLE_NODES 655 void __init initmem_init(void) 656 { 657 #ifdef CONFIG_HIGHMEM 658 highstart_pfn = highend_pfn = max_pfn; 659 if (max_pfn > max_low_pfn) 660 highstart_pfn = max_low_pfn; 661 printk(KERN_NOTICE "%ldMB HIGHMEM available.\n", 662 pages_to_mb(highend_pfn - highstart_pfn)); 663 high_memory = (void *) __va(highstart_pfn * PAGE_SIZE - 1) + 1; 664 #else 665 high_memory = (void *) __va(max_low_pfn * PAGE_SIZE - 1) + 1; 666 #endif 667 668 memblock_set_node(0, (phys_addr_t)ULLONG_MAX, 0); 669 sparse_memory_present_with_active_regions(0); 670 671 #ifdef CONFIG_FLATMEM 672 max_mapnr = IS_ENABLED(CONFIG_HIGHMEM) ? highend_pfn : max_low_pfn; 673 #endif 674 __vmalloc_start_set = true; 675 676 printk(KERN_NOTICE "%ldMB LOWMEM available.\n", 677 pages_to_mb(max_low_pfn)); 678 679 setup_bootmem_allocator(); 680 } 681 #endif /* !CONFIG_NEED_MULTIPLE_NODES */ 682 683 void __init setup_bootmem_allocator(void) 684 { 685 printk(KERN_INFO " mapped low ram: 0 - %08lx\n", 686 max_pfn_mapped<<PAGE_SHIFT); 687 printk(KERN_INFO " low ram: 0 - %08lx\n", max_low_pfn<<PAGE_SHIFT); 688 } 689 690 /* 691 * paging_init() sets up the page tables - note that the first 8MB are 692 * already mapped by head.S. 693 * 694 * This routines also unmaps the page at virtual kernel address 0, so 695 * that we can trap those pesky NULL-reference errors in the kernel. 696 */ 697 void __init paging_init(void) 698 { 699 pagetable_init(); 700 701 __flush_tlb_all(); 702 703 kmap_init(); 704 705 /* 706 * NOTE: at this point the bootmem allocator is fully available. 707 */ 708 olpc_dt_build_devicetree(); 709 sparse_memory_present_with_active_regions(MAX_NUMNODES); 710 sparse_init(); 711 zone_sizes_init(); 712 } 713 714 /* 715 * Test if the WP bit works in supervisor mode. It isn't supported on 386's 716 * and also on some strange 486's. All 586+'s are OK. This used to involve 717 * black magic jumps to work around some nasty CPU bugs, but fortunately the 718 * switch to using exceptions got rid of all that. 719 */ 720 static void __init test_wp_bit(void) 721 { 722 printk(KERN_INFO 723 "Checking if this processor honours the WP bit even in supervisor mode..."); 724 725 /* Any page-aligned address will do, the test is non-destructive */ 726 __set_fixmap(FIX_WP_TEST, __pa(&swapper_pg_dir), PAGE_KERNEL_RO); 727 boot_cpu_data.wp_works_ok = do_test_wp_bit(); 728 clear_fixmap(FIX_WP_TEST); 729 730 if (!boot_cpu_data.wp_works_ok) { 731 printk(KERN_CONT "No.\n"); 732 panic("Linux doesn't support CPUs with broken WP."); 733 } else { 734 printk(KERN_CONT "Ok.\n"); 735 } 736 } 737 738 void __init mem_init(void) 739 { 740 pci_iommu_alloc(); 741 742 #ifdef CONFIG_FLATMEM 743 BUG_ON(!mem_map); 744 #endif 745 /* 746 * With CONFIG_DEBUG_PAGEALLOC initialization of highmem pages has to 747 * be done before free_all_bootmem(). Memblock use free low memory for 748 * temporary data (see find_range_array()) and for this purpose can use 749 * pages that was already passed to the buddy allocator, hence marked as 750 * not accessible in the page tables when compiled with 751 * CONFIG_DEBUG_PAGEALLOC. Otherwise order of initialization is not 752 * important here. 753 */ 754 set_highmem_pages_init(); 755 756 /* this will put all low memory onto the freelists */ 757 free_all_bootmem(); 758 759 after_bootmem = 1; 760 761 mem_init_print_info(NULL); 762 printk(KERN_INFO "virtual kernel memory layout:\n" 763 " fixmap : 0x%08lx - 0x%08lx (%4ld kB)\n" 764 #ifdef CONFIG_HIGHMEM 765 " pkmap : 0x%08lx - 0x%08lx (%4ld kB)\n" 766 #endif 767 " vmalloc : 0x%08lx - 0x%08lx (%4ld MB)\n" 768 " lowmem : 0x%08lx - 0x%08lx (%4ld MB)\n" 769 " .init : 0x%08lx - 0x%08lx (%4ld kB)\n" 770 " .data : 0x%08lx - 0x%08lx (%4ld kB)\n" 771 " .text : 0x%08lx - 0x%08lx (%4ld kB)\n", 772 FIXADDR_START, FIXADDR_TOP, 773 (FIXADDR_TOP - FIXADDR_START) >> 10, 774 775 #ifdef CONFIG_HIGHMEM 776 PKMAP_BASE, PKMAP_BASE+LAST_PKMAP*PAGE_SIZE, 777 (LAST_PKMAP*PAGE_SIZE) >> 10, 778 #endif 779 780 VMALLOC_START, VMALLOC_END, 781 (VMALLOC_END - VMALLOC_START) >> 20, 782 783 (unsigned long)__va(0), (unsigned long)high_memory, 784 ((unsigned long)high_memory - (unsigned long)__va(0)) >> 20, 785 786 (unsigned long)&__init_begin, (unsigned long)&__init_end, 787 ((unsigned long)&__init_end - 788 (unsigned long)&__init_begin) >> 10, 789 790 (unsigned long)&_etext, (unsigned long)&_edata, 791 ((unsigned long)&_edata - (unsigned long)&_etext) >> 10, 792 793 (unsigned long)&_text, (unsigned long)&_etext, 794 ((unsigned long)&_etext - (unsigned long)&_text) >> 10); 795 796 /* 797 * Check boundaries twice: Some fundamental inconsistencies can 798 * be detected at build time already. 799 */ 800 #define __FIXADDR_TOP (-PAGE_SIZE) 801 #ifdef CONFIG_HIGHMEM 802 BUILD_BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE > FIXADDR_START); 803 BUILD_BUG_ON(VMALLOC_END > PKMAP_BASE); 804 #endif 805 #define high_memory (-128UL << 20) 806 BUILD_BUG_ON(VMALLOC_START >= VMALLOC_END); 807 #undef high_memory 808 #undef __FIXADDR_TOP 809 810 #ifdef CONFIG_HIGHMEM 811 BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE > FIXADDR_START); 812 BUG_ON(VMALLOC_END > PKMAP_BASE); 813 #endif 814 BUG_ON(VMALLOC_START >= VMALLOC_END); 815 BUG_ON((unsigned long)high_memory > VMALLOC_START); 816 817 if (boot_cpu_data.wp_works_ok < 0) 818 test_wp_bit(); 819 } 820 821 #ifdef CONFIG_MEMORY_HOTPLUG 822 int arch_add_memory(int nid, u64 start, u64 size) 823 { 824 struct pglist_data *pgdata = NODE_DATA(nid); 825 struct zone *zone = pgdata->node_zones + ZONE_HIGHMEM; 826 unsigned long start_pfn = start >> PAGE_SHIFT; 827 unsigned long nr_pages = size >> PAGE_SHIFT; 828 829 return __add_pages(nid, zone, start_pfn, nr_pages); 830 } 831 832 #ifdef CONFIG_MEMORY_HOTREMOVE 833 int arch_remove_memory(u64 start, u64 size) 834 { 835 unsigned long start_pfn = start >> PAGE_SHIFT; 836 unsigned long nr_pages = size >> PAGE_SHIFT; 837 struct zone *zone; 838 839 zone = page_zone(pfn_to_page(start_pfn)); 840 return __remove_pages(zone, start_pfn, nr_pages); 841 } 842 #endif 843 #endif 844 845 /* 846 * This function cannot be __init, since exceptions don't work in that 847 * section. Put this after the callers, so that it cannot be inlined. 848 */ 849 static noinline int do_test_wp_bit(void) 850 { 851 char tmp_reg; 852 int flag; 853 854 __asm__ __volatile__( 855 " movb %0, %1 \n" 856 "1: movb %1, %0 \n" 857 " xorl %2, %2 \n" 858 "2: \n" 859 _ASM_EXTABLE(1b,2b) 860 :"=m" (*(char *)fix_to_virt(FIX_WP_TEST)), 861 "=q" (tmp_reg), 862 "=r" (flag) 863 :"2" (1) 864 :"memory"); 865 866 return flag; 867 } 868 869 #ifdef CONFIG_DEBUG_RODATA 870 const int rodata_test_data = 0xC3; 871 EXPORT_SYMBOL_GPL(rodata_test_data); 872 873 int kernel_set_to_readonly __read_mostly; 874 875 void set_kernel_text_rw(void) 876 { 877 unsigned long start = PFN_ALIGN(_text); 878 unsigned long size = PFN_ALIGN(_etext) - start; 879 880 if (!kernel_set_to_readonly) 881 return; 882 883 pr_debug("Set kernel text: %lx - %lx for read write\n", 884 start, start+size); 885 886 set_pages_rw(virt_to_page(start), size >> PAGE_SHIFT); 887 } 888 889 void set_kernel_text_ro(void) 890 { 891 unsigned long start = PFN_ALIGN(_text); 892 unsigned long size = PFN_ALIGN(_etext) - start; 893 894 if (!kernel_set_to_readonly) 895 return; 896 897 pr_debug("Set kernel text: %lx - %lx for read only\n", 898 start, start+size); 899 900 set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT); 901 } 902 903 static void mark_nxdata_nx(void) 904 { 905 /* 906 * When this called, init has already been executed and released, 907 * so everything past _etext should be NX. 908 */ 909 unsigned long start = PFN_ALIGN(_etext); 910 /* 911 * This comes from is_kernel_text upper limit. Also HPAGE where used: 912 */ 913 unsigned long size = (((unsigned long)__init_end + HPAGE_SIZE) & HPAGE_MASK) - start; 914 915 if (__supported_pte_mask & _PAGE_NX) 916 printk(KERN_INFO "NX-protecting the kernel data: %luk\n", size >> 10); 917 set_pages_nx(virt_to_page(start), size >> PAGE_SHIFT); 918 } 919 920 void mark_rodata_ro(void) 921 { 922 unsigned long start = PFN_ALIGN(_text); 923 unsigned long size = PFN_ALIGN(_etext) - start; 924 925 set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT); 926 printk(KERN_INFO "Write protecting the kernel text: %luk\n", 927 size >> 10); 928 929 kernel_set_to_readonly = 1; 930 931 #ifdef CONFIG_CPA_DEBUG 932 printk(KERN_INFO "Testing CPA: Reverting %lx-%lx\n", 933 start, start+size); 934 set_pages_rw(virt_to_page(start), size>>PAGE_SHIFT); 935 936 printk(KERN_INFO "Testing CPA: write protecting again\n"); 937 set_pages_ro(virt_to_page(start), size>>PAGE_SHIFT); 938 #endif 939 940 start += size; 941 size = (unsigned long)__end_rodata - start; 942 set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT); 943 printk(KERN_INFO "Write protecting the kernel read-only data: %luk\n", 944 size >> 10); 945 rodata_test(); 946 947 #ifdef CONFIG_CPA_DEBUG 948 printk(KERN_INFO "Testing CPA: undo %lx-%lx\n", start, start + size); 949 set_pages_rw(virt_to_page(start), size >> PAGE_SHIFT); 950 951 printk(KERN_INFO "Testing CPA: write protecting again\n"); 952 set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT); 953 #endif 954 mark_nxdata_nx(); 955 } 956 #endif 957 958