1 /* 2 * linux/arch/i386/mm/init.c 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/module.h> 10 #include <linux/signal.h> 11 #include <linux/sched.h> 12 #include <linux/kernel.h> 13 #include <linux/errno.h> 14 #include <linux/string.h> 15 #include <linux/types.h> 16 #include <linux/ptrace.h> 17 #include <linux/mman.h> 18 #include <linux/mm.h> 19 #include <linux/hugetlb.h> 20 #include <linux/swap.h> 21 #include <linux/smp.h> 22 #include <linux/init.h> 23 #include <linux/highmem.h> 24 #include <linux/pagemap.h> 25 #include <linux/pfn.h> 26 #include <linux/poison.h> 27 #include <linux/bootmem.h> 28 #include <linux/slab.h> 29 #include <linux/proc_fs.h> 30 #include <linux/memory_hotplug.h> 31 #include <linux/initrd.h> 32 #include <linux/cpumask.h> 33 34 #include <asm/processor.h> 35 #include <asm/system.h> 36 #include <asm/uaccess.h> 37 #include <asm/pgtable.h> 38 #include <asm/dma.h> 39 #include <asm/fixmap.h> 40 #include <asm/e820.h> 41 #include <asm/apic.h> 42 #include <asm/bugs.h> 43 #include <asm/tlb.h> 44 #include <asm/tlbflush.h> 45 #include <asm/pgalloc.h> 46 #include <asm/sections.h> 47 #include <asm/paravirt.h> 48 49 unsigned int __VMALLOC_RESERVE = 128 << 20; 50 51 DEFINE_PER_CPU(struct mmu_gather, mmu_gathers); 52 unsigned long highstart_pfn, highend_pfn; 53 54 static noinline int do_test_wp_bit(void); 55 56 /* 57 * Creates a middle page table and puts a pointer to it in the 58 * given global directory entry. This only returns the gd entry 59 * in non-PAE compilation mode, since the middle layer is folded. 60 */ 61 static pmd_t * __init one_md_table_init(pgd_t *pgd) 62 { 63 pud_t *pud; 64 pmd_t *pmd_table; 65 66 #ifdef CONFIG_X86_PAE 67 if (!(pgd_val(*pgd) & _PAGE_PRESENT)) { 68 pmd_table = (pmd_t *) alloc_bootmem_low_pages(PAGE_SIZE); 69 70 paravirt_alloc_pd(&init_mm, __pa(pmd_table) >> PAGE_SHIFT); 71 set_pgd(pgd, __pgd(__pa(pmd_table) | _PAGE_PRESENT)); 72 pud = pud_offset(pgd, 0); 73 BUG_ON(pmd_table != pmd_offset(pud, 0)); 74 } 75 #endif 76 pud = pud_offset(pgd, 0); 77 pmd_table = pmd_offset(pud, 0); 78 79 return pmd_table; 80 } 81 82 /* 83 * Create a page table and place a pointer to it in a middle page 84 * directory entry: 85 */ 86 static pte_t * __init one_page_table_init(pmd_t *pmd) 87 { 88 if (!(pmd_val(*pmd) & _PAGE_PRESENT)) { 89 pte_t *page_table = NULL; 90 91 #ifdef CONFIG_DEBUG_PAGEALLOC 92 page_table = (pte_t *) alloc_bootmem_pages(PAGE_SIZE); 93 #endif 94 if (!page_table) { 95 page_table = 96 (pte_t *)alloc_bootmem_low_pages(PAGE_SIZE); 97 } 98 99 paravirt_alloc_pt(&init_mm, __pa(page_table) >> PAGE_SHIFT); 100 set_pmd(pmd, __pmd(__pa(page_table) | _PAGE_TABLE)); 101 BUG_ON(page_table != pte_offset_kernel(pmd, 0)); 102 } 103 104 return pte_offset_kernel(pmd, 0); 105 } 106 107 /* 108 * This function initializes a certain range of kernel virtual memory 109 * with new bootmem page tables, everywhere page tables are missing in 110 * the given range. 111 * 112 * NOTE: The pagetables are allocated contiguous on the physical space 113 * so we can cache the place of the first one and move around without 114 * checking the pgd every time. 115 */ 116 static void __init 117 page_table_range_init(unsigned long start, unsigned long end, pgd_t *pgd_base) 118 { 119 int pgd_idx, pmd_idx; 120 unsigned long vaddr; 121 pgd_t *pgd; 122 pmd_t *pmd; 123 124 vaddr = start; 125 pgd_idx = pgd_index(vaddr); 126 pmd_idx = pmd_index(vaddr); 127 pgd = pgd_base + pgd_idx; 128 129 for ( ; (pgd_idx < PTRS_PER_PGD) && (vaddr != end); pgd++, pgd_idx++) { 130 pmd = one_md_table_init(pgd); 131 pmd = pmd + pmd_index(vaddr); 132 for (; (pmd_idx < PTRS_PER_PMD) && (vaddr != end); 133 pmd++, pmd_idx++) { 134 one_page_table_init(pmd); 135 136 vaddr += PMD_SIZE; 137 } 138 pmd_idx = 0; 139 } 140 } 141 142 static inline int is_kernel_text(unsigned long addr) 143 { 144 if (addr >= PAGE_OFFSET && addr <= (unsigned long)__init_end) 145 return 1; 146 return 0; 147 } 148 149 /* 150 * This maps the physical memory to kernel virtual address space, a total 151 * of max_low_pfn pages, by creating page tables starting from address 152 * PAGE_OFFSET: 153 */ 154 static void __init kernel_physical_mapping_init(pgd_t *pgd_base) 155 { 156 int pgd_idx, pmd_idx, pte_ofs; 157 unsigned long pfn; 158 pgd_t *pgd; 159 pmd_t *pmd; 160 pte_t *pte; 161 162 pgd_idx = pgd_index(PAGE_OFFSET); 163 pgd = pgd_base + pgd_idx; 164 pfn = 0; 165 166 for (; pgd_idx < PTRS_PER_PGD; pgd++, pgd_idx++) { 167 pmd = one_md_table_init(pgd); 168 if (pfn >= max_low_pfn) 169 continue; 170 171 for (pmd_idx = 0; 172 pmd_idx < PTRS_PER_PMD && pfn < max_low_pfn; 173 pmd++, pmd_idx++) { 174 unsigned int addr = pfn * PAGE_SIZE + PAGE_OFFSET; 175 176 /* 177 * Map with big pages if possible, otherwise 178 * create normal page tables: 179 */ 180 if (cpu_has_pse) { 181 unsigned int addr2; 182 pgprot_t prot = PAGE_KERNEL_LARGE; 183 184 addr2 = (pfn + PTRS_PER_PTE-1) * PAGE_SIZE + 185 PAGE_OFFSET + PAGE_SIZE-1; 186 187 if (is_kernel_text(addr) || 188 is_kernel_text(addr2)) 189 prot = PAGE_KERNEL_LARGE_EXEC; 190 191 set_pmd(pmd, pfn_pmd(pfn, prot)); 192 193 pfn += PTRS_PER_PTE; 194 continue; 195 } 196 pte = one_page_table_init(pmd); 197 198 for (pte_ofs = 0; 199 pte_ofs < PTRS_PER_PTE && pfn < max_low_pfn; 200 pte++, pfn++, pte_ofs++, addr += PAGE_SIZE) { 201 pgprot_t prot = PAGE_KERNEL; 202 203 if (is_kernel_text(addr)) 204 prot = PAGE_KERNEL_EXEC; 205 206 set_pte(pte, pfn_pte(pfn, prot)); 207 } 208 } 209 } 210 } 211 212 static inline int page_kills_ppro(unsigned long pagenr) 213 { 214 if (pagenr >= 0x70000 && pagenr <= 0x7003F) 215 return 1; 216 return 0; 217 } 218 219 #ifdef CONFIG_HIGHMEM 220 pte_t *kmap_pte; 221 pgprot_t kmap_prot; 222 223 static inline pte_t *kmap_get_fixmap_pte(unsigned long vaddr) 224 { 225 return pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr), 226 vaddr), vaddr), vaddr); 227 } 228 229 static void __init kmap_init(void) 230 { 231 unsigned long kmap_vstart; 232 233 /* 234 * Cache the first kmap pte: 235 */ 236 kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN); 237 kmap_pte = kmap_get_fixmap_pte(kmap_vstart); 238 239 kmap_prot = PAGE_KERNEL; 240 } 241 242 static void __init permanent_kmaps_init(pgd_t *pgd_base) 243 { 244 unsigned long vaddr; 245 pgd_t *pgd; 246 pud_t *pud; 247 pmd_t *pmd; 248 pte_t *pte; 249 250 vaddr = PKMAP_BASE; 251 page_table_range_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, pgd_base); 252 253 pgd = swapper_pg_dir + pgd_index(vaddr); 254 pud = pud_offset(pgd, vaddr); 255 pmd = pmd_offset(pud, vaddr); 256 pte = pte_offset_kernel(pmd, vaddr); 257 pkmap_page_table = pte; 258 } 259 260 static void __meminit free_new_highpage(struct page *page) 261 { 262 init_page_count(page); 263 __free_page(page); 264 totalhigh_pages++; 265 } 266 267 void __init add_one_highpage_init(struct page *page, int pfn, int bad_ppro) 268 { 269 if (page_is_ram(pfn) && !(bad_ppro && page_kills_ppro(pfn))) { 270 ClearPageReserved(page); 271 free_new_highpage(page); 272 } else 273 SetPageReserved(page); 274 } 275 276 static int __meminit 277 add_one_highpage_hotplug(struct page *page, unsigned long pfn) 278 { 279 free_new_highpage(page); 280 totalram_pages++; 281 #ifdef CONFIG_FLATMEM 282 max_mapnr = max(pfn, max_mapnr); 283 #endif 284 num_physpages++; 285 286 return 0; 287 } 288 289 /* 290 * Not currently handling the NUMA case. 291 * Assuming single node and all memory that 292 * has been added dynamically that would be 293 * onlined here is in HIGHMEM. 294 */ 295 void __meminit online_page(struct page *page) 296 { 297 ClearPageReserved(page); 298 add_one_highpage_hotplug(page, page_to_pfn(page)); 299 } 300 301 #ifndef CONFIG_NUMA 302 static void __init set_highmem_pages_init(int bad_ppro) 303 { 304 int pfn; 305 306 for (pfn = highstart_pfn; pfn < highend_pfn; pfn++) { 307 /* 308 * Holes under sparsemem might not have no mem_map[]: 309 */ 310 if (pfn_valid(pfn)) 311 add_one_highpage_init(pfn_to_page(pfn), pfn, bad_ppro); 312 } 313 totalram_pages += totalhigh_pages; 314 } 315 #endif /* !CONFIG_NUMA */ 316 317 #else 318 # define kmap_init() do { } while (0) 319 # define permanent_kmaps_init(pgd_base) do { } while (0) 320 # define set_highmem_pages_init(bad_ppro) do { } while (0) 321 #endif /* CONFIG_HIGHMEM */ 322 323 pteval_t __PAGE_KERNEL = _PAGE_KERNEL; 324 EXPORT_SYMBOL(__PAGE_KERNEL); 325 326 pteval_t __PAGE_KERNEL_EXEC = _PAGE_KERNEL_EXEC; 327 328 void __init native_pagetable_setup_start(pgd_t *base) 329 { 330 #ifdef CONFIG_X86_PAE 331 int i; 332 333 /* 334 * Init entries of the first-level page table to the 335 * zero page, if they haven't already been set up. 336 * 337 * In a normal native boot, we'll be running on a 338 * pagetable rooted in swapper_pg_dir, but not in PAE 339 * mode, so this will end up clobbering the mappings 340 * for the lower 24Mbytes of the address space, 341 * without affecting the kernel address space. 342 */ 343 for (i = 0; i < USER_PTRS_PER_PGD; i++) 344 set_pgd(&base[i], 345 __pgd(__pa(empty_zero_page) | _PAGE_PRESENT)); 346 347 /* Make sure kernel address space is empty so that a pagetable 348 will be allocated for it. */ 349 memset(&base[USER_PTRS_PER_PGD], 0, 350 KERNEL_PGD_PTRS * sizeof(pgd_t)); 351 #else 352 paravirt_alloc_pd(&init_mm, __pa(base) >> PAGE_SHIFT); 353 #endif 354 } 355 356 void __init native_pagetable_setup_done(pgd_t *base) 357 { 358 #ifdef CONFIG_X86_PAE 359 /* 360 * Add low memory identity-mappings - SMP needs it when 361 * starting up on an AP from real-mode. In the non-PAE 362 * case we already have these mappings through head.S. 363 * All user-space mappings are explicitly cleared after 364 * SMP startup. 365 */ 366 set_pgd(&base[0], base[USER_PTRS_PER_PGD]); 367 #endif 368 } 369 370 /* 371 * Build a proper pagetable for the kernel mappings. Up until this 372 * point, we've been running on some set of pagetables constructed by 373 * the boot process. 374 * 375 * If we're booting on native hardware, this will be a pagetable 376 * constructed in arch/i386/kernel/head.S, and not running in PAE mode 377 * (even if we'll end up running in PAE). The root of the pagetable 378 * will be swapper_pg_dir. 379 * 380 * If we're booting paravirtualized under a hypervisor, then there are 381 * more options: we may already be running PAE, and the pagetable may 382 * or may not be based in swapper_pg_dir. In any case, 383 * paravirt_pagetable_setup_start() will set up swapper_pg_dir 384 * appropriately for the rest of the initialization to work. 385 * 386 * In general, pagetable_init() assumes that the pagetable may already 387 * be partially populated, and so it avoids stomping on any existing 388 * mappings. 389 */ 390 static void __init pagetable_init(void) 391 { 392 pgd_t *pgd_base = swapper_pg_dir; 393 unsigned long vaddr, end; 394 395 paravirt_pagetable_setup_start(pgd_base); 396 397 /* Enable PSE if available */ 398 if (cpu_has_pse) 399 set_in_cr4(X86_CR4_PSE); 400 401 /* Enable PGE if available */ 402 if (cpu_has_pge) { 403 set_in_cr4(X86_CR4_PGE); 404 __PAGE_KERNEL |= _PAGE_GLOBAL; 405 __PAGE_KERNEL_EXEC |= _PAGE_GLOBAL; 406 } 407 408 kernel_physical_mapping_init(pgd_base); 409 remap_numa_kva(); 410 411 /* 412 * Fixed mappings, only the page table structure has to be 413 * created - mappings will be set by set_fixmap(): 414 */ 415 early_ioremap_clear(); 416 vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK; 417 end = (FIXADDR_TOP + PMD_SIZE - 1) & PMD_MASK; 418 page_table_range_init(vaddr, end, pgd_base); 419 early_ioremap_reset(); 420 421 permanent_kmaps_init(pgd_base); 422 423 paravirt_pagetable_setup_done(pgd_base); 424 } 425 426 #ifdef CONFIG_ACPI_SLEEP 427 /* 428 * ACPI suspend needs this for resume, because things like the intel-agp 429 * driver might have split up a kernel 4MB mapping. 430 */ 431 char swsusp_pg_dir[PAGE_SIZE] 432 __attribute__ ((aligned(PAGE_SIZE))); 433 434 static inline void save_pg_dir(void) 435 { 436 memcpy(swsusp_pg_dir, swapper_pg_dir, PAGE_SIZE); 437 } 438 #else /* !CONFIG_ACPI_SLEEP */ 439 static inline void save_pg_dir(void) 440 { 441 } 442 #endif /* !CONFIG_ACPI_SLEEP */ 443 444 void zap_low_mappings(void) 445 { 446 int i; 447 448 save_pg_dir(); 449 450 /* 451 * Zap initial low-memory mappings. 452 * 453 * Note that "pgd_clear()" doesn't do it for 454 * us, because pgd_clear() is a no-op on i386. 455 */ 456 for (i = 0; i < USER_PTRS_PER_PGD; i++) { 457 #ifdef CONFIG_X86_PAE 458 set_pgd(swapper_pg_dir+i, __pgd(1 + __pa(empty_zero_page))); 459 #else 460 set_pgd(swapper_pg_dir+i, __pgd(0)); 461 #endif 462 } 463 flush_tlb_all(); 464 } 465 466 int nx_enabled; 467 468 pteval_t __supported_pte_mask __read_mostly = ~_PAGE_NX; 469 EXPORT_SYMBOL_GPL(__supported_pte_mask); 470 471 #ifdef CONFIG_X86_PAE 472 473 static int disable_nx __initdata; 474 475 /* 476 * noexec = on|off 477 * 478 * Control non executable mappings. 479 * 480 * on Enable 481 * off Disable 482 */ 483 static int __init noexec_setup(char *str) 484 { 485 if (!str || !strcmp(str, "on")) { 486 if (cpu_has_nx) { 487 __supported_pte_mask |= _PAGE_NX; 488 disable_nx = 0; 489 } 490 } else { 491 if (!strcmp(str, "off")) { 492 disable_nx = 1; 493 __supported_pte_mask &= ~_PAGE_NX; 494 } else { 495 return -EINVAL; 496 } 497 } 498 499 return 0; 500 } 501 early_param("noexec", noexec_setup); 502 503 static void __init set_nx(void) 504 { 505 unsigned int v[4], l, h; 506 507 if (cpu_has_pae && (cpuid_eax(0x80000000) > 0x80000001)) { 508 cpuid(0x80000001, &v[0], &v[1], &v[2], &v[3]); 509 510 if ((v[3] & (1 << 20)) && !disable_nx) { 511 rdmsr(MSR_EFER, l, h); 512 l |= EFER_NX; 513 wrmsr(MSR_EFER, l, h); 514 nx_enabled = 1; 515 __supported_pte_mask |= _PAGE_NX; 516 } 517 } 518 } 519 #endif 520 521 /* 522 * paging_init() sets up the page tables - note that the first 8MB are 523 * already mapped by head.S. 524 * 525 * This routines also unmaps the page at virtual kernel address 0, so 526 * that we can trap those pesky NULL-reference errors in the kernel. 527 */ 528 void __init paging_init(void) 529 { 530 #ifdef CONFIG_X86_PAE 531 set_nx(); 532 if (nx_enabled) 533 printk(KERN_INFO "NX (Execute Disable) protection: active\n"); 534 #endif 535 pagetable_init(); 536 537 load_cr3(swapper_pg_dir); 538 539 #ifdef CONFIG_X86_PAE 540 /* 541 * We will bail out later - printk doesn't work right now so 542 * the user would just see a hanging kernel. 543 */ 544 if (cpu_has_pae) 545 set_in_cr4(X86_CR4_PAE); 546 #endif 547 __flush_tlb_all(); 548 549 kmap_init(); 550 } 551 552 /* 553 * Test if the WP bit works in supervisor mode. It isn't supported on 386's 554 * and also on some strange 486's (NexGen etc.). All 586+'s are OK. This 555 * used to involve black magic jumps to work around some nasty CPU bugs, 556 * but fortunately the switch to using exceptions got rid of all that. 557 */ 558 static void __init test_wp_bit(void) 559 { 560 printk(KERN_INFO 561 "Checking if this processor honours the WP bit even in supervisor mode..."); 562 563 /* Any page-aligned address will do, the test is non-destructive */ 564 __set_fixmap(FIX_WP_TEST, __pa(&swapper_pg_dir), PAGE_READONLY); 565 boot_cpu_data.wp_works_ok = do_test_wp_bit(); 566 clear_fixmap(FIX_WP_TEST); 567 568 if (!boot_cpu_data.wp_works_ok) { 569 printk(KERN_CONT "No.\n"); 570 #ifdef CONFIG_X86_WP_WORKS_OK 571 panic( 572 "This kernel doesn't support CPU's with broken WP. Recompile it for a 386!"); 573 #endif 574 } else { 575 printk(KERN_CONT "Ok.\n"); 576 } 577 } 578 579 static struct kcore_list kcore_mem, kcore_vmalloc; 580 581 void __init mem_init(void) 582 { 583 int codesize, reservedpages, datasize, initsize; 584 int tmp, bad_ppro; 585 586 #ifdef CONFIG_FLATMEM 587 BUG_ON(!mem_map); 588 #endif 589 bad_ppro = ppro_with_ram_bug(); 590 591 #ifdef CONFIG_HIGHMEM 592 /* check that fixmap and pkmap do not overlap */ 593 if (PKMAP_BASE + LAST_PKMAP*PAGE_SIZE >= FIXADDR_START) { 594 printk(KERN_ERR 595 "fixmap and kmap areas overlap - this will crash\n"); 596 printk(KERN_ERR "pkstart: %lxh pkend: %lxh fixstart %lxh\n", 597 PKMAP_BASE, PKMAP_BASE + LAST_PKMAP*PAGE_SIZE, 598 FIXADDR_START); 599 BUG(); 600 } 601 #endif 602 /* this will put all low memory onto the freelists */ 603 totalram_pages += free_all_bootmem(); 604 605 reservedpages = 0; 606 for (tmp = 0; tmp < max_low_pfn; tmp++) 607 /* 608 * Only count reserved RAM pages: 609 */ 610 if (page_is_ram(tmp) && PageReserved(pfn_to_page(tmp))) 611 reservedpages++; 612 613 set_highmem_pages_init(bad_ppro); 614 615 codesize = (unsigned long) &_etext - (unsigned long) &_text; 616 datasize = (unsigned long) &_edata - (unsigned long) &_etext; 617 initsize = (unsigned long) &__init_end - (unsigned long) &__init_begin; 618 619 kclist_add(&kcore_mem, __va(0), max_low_pfn << PAGE_SHIFT); 620 kclist_add(&kcore_vmalloc, (void *)VMALLOC_START, 621 VMALLOC_END-VMALLOC_START); 622 623 printk(KERN_INFO "Memory: %luk/%luk available (%dk kernel code, " 624 "%dk reserved, %dk data, %dk init, %ldk highmem)\n", 625 (unsigned long) nr_free_pages() << (PAGE_SHIFT-10), 626 num_physpages << (PAGE_SHIFT-10), 627 codesize >> 10, 628 reservedpages << (PAGE_SHIFT-10), 629 datasize >> 10, 630 initsize >> 10, 631 (unsigned long) (totalhigh_pages << (PAGE_SHIFT-10)) 632 ); 633 634 #if 1 /* double-sanity-check paranoia */ 635 printk(KERN_INFO "virtual kernel memory layout:\n" 636 " fixmap : 0x%08lx - 0x%08lx (%4ld kB)\n" 637 #ifdef CONFIG_HIGHMEM 638 " pkmap : 0x%08lx - 0x%08lx (%4ld kB)\n" 639 #endif 640 " vmalloc : 0x%08lx - 0x%08lx (%4ld MB)\n" 641 " lowmem : 0x%08lx - 0x%08lx (%4ld MB)\n" 642 " .init : 0x%08lx - 0x%08lx (%4ld kB)\n" 643 " .data : 0x%08lx - 0x%08lx (%4ld kB)\n" 644 " .text : 0x%08lx - 0x%08lx (%4ld kB)\n", 645 FIXADDR_START, FIXADDR_TOP, 646 (FIXADDR_TOP - FIXADDR_START) >> 10, 647 648 #ifdef CONFIG_HIGHMEM 649 PKMAP_BASE, PKMAP_BASE+LAST_PKMAP*PAGE_SIZE, 650 (LAST_PKMAP*PAGE_SIZE) >> 10, 651 #endif 652 653 VMALLOC_START, VMALLOC_END, 654 (VMALLOC_END - VMALLOC_START) >> 20, 655 656 (unsigned long)__va(0), (unsigned long)high_memory, 657 ((unsigned long)high_memory - (unsigned long)__va(0)) >> 20, 658 659 (unsigned long)&__init_begin, (unsigned long)&__init_end, 660 ((unsigned long)&__init_end - 661 (unsigned long)&__init_begin) >> 10, 662 663 (unsigned long)&_etext, (unsigned long)&_edata, 664 ((unsigned long)&_edata - (unsigned long)&_etext) >> 10, 665 666 (unsigned long)&_text, (unsigned long)&_etext, 667 ((unsigned long)&_etext - (unsigned long)&_text) >> 10); 668 669 #ifdef CONFIG_HIGHMEM 670 BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE > FIXADDR_START); 671 BUG_ON(VMALLOC_END > PKMAP_BASE); 672 #endif 673 BUG_ON(VMALLOC_START > VMALLOC_END); 674 BUG_ON((unsigned long)high_memory > VMALLOC_START); 675 #endif /* double-sanity-check paranoia */ 676 677 #ifdef CONFIG_X86_PAE 678 if (!cpu_has_pae) 679 panic("cannot execute a PAE-enabled kernel on a PAE-less CPU!"); 680 #endif 681 if (boot_cpu_data.wp_works_ok < 0) 682 test_wp_bit(); 683 684 /* 685 * Subtle. SMP is doing it's boot stuff late (because it has to 686 * fork idle threads) - but it also needs low mappings for the 687 * protected-mode entry to work. We zap these entries only after 688 * the WP-bit has been tested. 689 */ 690 #ifndef CONFIG_SMP 691 zap_low_mappings(); 692 #endif 693 } 694 695 #ifdef CONFIG_MEMORY_HOTPLUG 696 int arch_add_memory(int nid, u64 start, u64 size) 697 { 698 struct pglist_data *pgdata = NODE_DATA(nid); 699 struct zone *zone = pgdata->node_zones + ZONE_HIGHMEM; 700 unsigned long start_pfn = start >> PAGE_SHIFT; 701 unsigned long nr_pages = size >> PAGE_SHIFT; 702 703 return __add_pages(zone, start_pfn, nr_pages); 704 } 705 #endif 706 707 /* 708 * This function cannot be __init, since exceptions don't work in that 709 * section. Put this after the callers, so that it cannot be inlined. 710 */ 711 static noinline int do_test_wp_bit(void) 712 { 713 char tmp_reg; 714 int flag; 715 716 __asm__ __volatile__( 717 " movb %0, %1 \n" 718 "1: movb %1, %0 \n" 719 " xorl %2, %2 \n" 720 "2: \n" 721 ".section __ex_table, \"a\"\n" 722 " .align 4 \n" 723 " .long 1b, 2b \n" 724 ".previous \n" 725 :"=m" (*(char *)fix_to_virt(FIX_WP_TEST)), 726 "=q" (tmp_reg), 727 "=r" (flag) 728 :"2" (1) 729 :"memory"); 730 731 return flag; 732 } 733 734 #ifdef CONFIG_DEBUG_RODATA 735 const int rodata_test_data = 0xC3; 736 EXPORT_SYMBOL_GPL(rodata_test_data); 737 738 void mark_rodata_ro(void) 739 { 740 unsigned long start = PFN_ALIGN(_text); 741 unsigned long size = PFN_ALIGN(_etext) - start; 742 743 #ifndef CONFIG_KPROBES 744 #ifdef CONFIG_HOTPLUG_CPU 745 /* It must still be possible to apply SMP alternatives. */ 746 if (num_possible_cpus() <= 1) 747 #endif 748 { 749 set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT); 750 printk(KERN_INFO "Write protecting the kernel text: %luk\n", 751 size >> 10); 752 753 #ifdef CONFIG_CPA_DEBUG 754 printk(KERN_INFO "Testing CPA: Reverting %lx-%lx\n", 755 start, start+size); 756 set_pages_rw(virt_to_page(start), size>>PAGE_SHIFT); 757 758 printk(KERN_INFO "Testing CPA: write protecting again\n"); 759 set_pages_ro(virt_to_page(start), size>>PAGE_SHIFT); 760 #endif 761 } 762 #endif 763 start += size; 764 size = (unsigned long)__end_rodata - start; 765 set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT); 766 printk(KERN_INFO "Write protecting the kernel read-only data: %luk\n", 767 size >> 10); 768 rodata_test(); 769 770 #ifdef CONFIG_CPA_DEBUG 771 printk(KERN_INFO "Testing CPA: undo %lx-%lx\n", start, start + size); 772 set_pages_rw(virt_to_page(start), size >> PAGE_SHIFT); 773 774 printk(KERN_INFO "Testing CPA: write protecting again\n"); 775 set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT); 776 #endif 777 } 778 #endif 779 780 void free_init_pages(char *what, unsigned long begin, unsigned long end) 781 { 782 #ifdef CONFIG_DEBUG_PAGEALLOC 783 /* 784 * If debugging page accesses then do not free this memory but 785 * mark them not present - any buggy init-section access will 786 * create a kernel page fault: 787 */ 788 printk(KERN_INFO "debug: unmapping init memory %08lx..%08lx\n", 789 begin, PAGE_ALIGN(end)); 790 set_memory_np(begin, (end - begin) >> PAGE_SHIFT); 791 #else 792 unsigned long addr; 793 794 /* 795 * We just marked the kernel text read only above, now that 796 * we are going to free part of that, we need to make that 797 * writeable first. 798 */ 799 set_memory_rw(begin, (end - begin) >> PAGE_SHIFT); 800 801 for (addr = begin; addr < end; addr += PAGE_SIZE) { 802 ClearPageReserved(virt_to_page(addr)); 803 init_page_count(virt_to_page(addr)); 804 memset((void *)addr, POISON_FREE_INITMEM, PAGE_SIZE); 805 free_page(addr); 806 totalram_pages++; 807 } 808 printk(KERN_INFO "Freeing %s: %luk freed\n", what, (end - begin) >> 10); 809 #endif 810 } 811 812 void free_initmem(void) 813 { 814 free_init_pages("unused kernel memory", 815 (unsigned long)(&__init_begin), 816 (unsigned long)(&__init_end)); 817 } 818 819 #ifdef CONFIG_BLK_DEV_INITRD 820 void free_initrd_mem(unsigned long start, unsigned long end) 821 { 822 free_init_pages("initrd memory", start, end); 823 } 824 #endif 825