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/asm.h> 35 #include <asm/processor.h> 36 #include <asm/system.h> 37 #include <asm/uaccess.h> 38 #include <asm/pgtable.h> 39 #include <asm/dma.h> 40 #include <asm/fixmap.h> 41 #include <asm/e820.h> 42 #include <asm/apic.h> 43 #include <asm/bugs.h> 44 #include <asm/tlb.h> 45 #include <asm/tlbflush.h> 46 #include <asm/pgalloc.h> 47 #include <asm/sections.h> 48 #include <asm/paravirt.h> 49 #include <asm/setup.h> 50 #include <asm/cacheflush.h> 51 52 unsigned int __VMALLOC_RESERVE = 128 << 20; 53 54 unsigned long max_pfn_mapped; 55 56 DEFINE_PER_CPU(struct mmu_gather, mmu_gathers); 57 unsigned long highstart_pfn, highend_pfn; 58 59 static noinline int do_test_wp_bit(void); 60 61 /* 62 * Creates a middle page table and puts a pointer to it in the 63 * given global directory entry. This only returns the gd entry 64 * in non-PAE compilation mode, since the middle layer is folded. 65 */ 66 static pmd_t * __init one_md_table_init(pgd_t *pgd) 67 { 68 pud_t *pud; 69 pmd_t *pmd_table; 70 71 #ifdef CONFIG_X86_PAE 72 if (!(pgd_val(*pgd) & _PAGE_PRESENT)) { 73 pmd_table = (pmd_t *) alloc_bootmem_low_pages(PAGE_SIZE); 74 75 paravirt_alloc_pd(&init_mm, __pa(pmd_table) >> PAGE_SHIFT); 76 set_pgd(pgd, __pgd(__pa(pmd_table) | _PAGE_PRESENT)); 77 pud = pud_offset(pgd, 0); 78 BUG_ON(pmd_table != pmd_offset(pud, 0)); 79 } 80 #endif 81 pud = pud_offset(pgd, 0); 82 pmd_table = pmd_offset(pud, 0); 83 84 return pmd_table; 85 } 86 87 /* 88 * Create a page table and place a pointer to it in a middle page 89 * directory entry: 90 */ 91 static pte_t * __init one_page_table_init(pmd_t *pmd) 92 { 93 if (!(pmd_val(*pmd) & _PAGE_PRESENT)) { 94 pte_t *page_table = NULL; 95 96 #ifdef CONFIG_DEBUG_PAGEALLOC 97 page_table = (pte_t *) alloc_bootmem_pages(PAGE_SIZE); 98 #endif 99 if (!page_table) { 100 page_table = 101 (pte_t *)alloc_bootmem_low_pages(PAGE_SIZE); 102 } 103 104 paravirt_alloc_pt(&init_mm, __pa(page_table) >> PAGE_SHIFT); 105 set_pmd(pmd, __pmd(__pa(page_table) | _PAGE_TABLE)); 106 BUG_ON(page_table != pte_offset_kernel(pmd, 0)); 107 } 108 109 return pte_offset_kernel(pmd, 0); 110 } 111 112 /* 113 * This function initializes a certain range of kernel virtual memory 114 * with new bootmem page tables, everywhere page tables are missing in 115 * the given range. 116 * 117 * NOTE: The pagetables are allocated contiguous on the physical space 118 * so we can cache the place of the first one and move around without 119 * checking the pgd every time. 120 */ 121 static void __init 122 page_table_range_init(unsigned long start, unsigned long end, pgd_t *pgd_base) 123 { 124 int pgd_idx, pmd_idx; 125 unsigned long vaddr; 126 pgd_t *pgd; 127 pmd_t *pmd; 128 129 vaddr = start; 130 pgd_idx = pgd_index(vaddr); 131 pmd_idx = pmd_index(vaddr); 132 pgd = pgd_base + pgd_idx; 133 134 for ( ; (pgd_idx < PTRS_PER_PGD) && (vaddr != end); pgd++, pgd_idx++) { 135 pmd = one_md_table_init(pgd); 136 pmd = pmd + pmd_index(vaddr); 137 for (; (pmd_idx < PTRS_PER_PMD) && (vaddr != end); 138 pmd++, pmd_idx++) { 139 one_page_table_init(pmd); 140 141 vaddr += PMD_SIZE; 142 } 143 pmd_idx = 0; 144 } 145 } 146 147 static inline int is_kernel_text(unsigned long addr) 148 { 149 if (addr >= PAGE_OFFSET && addr <= (unsigned long)__init_end) 150 return 1; 151 return 0; 152 } 153 154 /* 155 * This maps the physical memory to kernel virtual address space, a total 156 * of max_low_pfn pages, by creating page tables starting from address 157 * PAGE_OFFSET: 158 */ 159 static void __init kernel_physical_mapping_init(pgd_t *pgd_base) 160 { 161 int pgd_idx, pmd_idx, pte_ofs; 162 unsigned long pfn; 163 pgd_t *pgd; 164 pmd_t *pmd; 165 pte_t *pte; 166 167 pgd_idx = pgd_index(PAGE_OFFSET); 168 pgd = pgd_base + pgd_idx; 169 pfn = 0; 170 171 for (; pgd_idx < PTRS_PER_PGD; pgd++, pgd_idx++) { 172 pmd = one_md_table_init(pgd); 173 if (pfn >= max_low_pfn) 174 continue; 175 176 for (pmd_idx = 0; 177 pmd_idx < PTRS_PER_PMD && pfn < max_low_pfn; 178 pmd++, pmd_idx++) { 179 unsigned int addr = pfn * PAGE_SIZE + PAGE_OFFSET; 180 181 /* 182 * Map with big pages if possible, otherwise 183 * create normal page tables: 184 * 185 * Don't use a large page for the first 2/4MB of memory 186 * because there are often fixed size MTRRs in there 187 * and overlapping MTRRs into large pages can cause 188 * slowdowns. 189 */ 190 if (cpu_has_pse && !(pgd_idx == 0 && pmd_idx == 0)) { 191 unsigned int addr2; 192 pgprot_t prot = PAGE_KERNEL_LARGE; 193 194 addr2 = (pfn + PTRS_PER_PTE-1) * PAGE_SIZE + 195 PAGE_OFFSET + PAGE_SIZE-1; 196 197 if (is_kernel_text(addr) || 198 is_kernel_text(addr2)) 199 prot = PAGE_KERNEL_LARGE_EXEC; 200 201 set_pmd(pmd, pfn_pmd(pfn, prot)); 202 203 pfn += PTRS_PER_PTE; 204 max_pfn_mapped = pfn; 205 continue; 206 } 207 pte = one_page_table_init(pmd); 208 209 for (pte_ofs = 0; 210 pte_ofs < PTRS_PER_PTE && pfn < max_low_pfn; 211 pte++, pfn++, pte_ofs++, addr += PAGE_SIZE) { 212 pgprot_t prot = PAGE_KERNEL; 213 214 if (is_kernel_text(addr)) 215 prot = PAGE_KERNEL_EXEC; 216 217 set_pte(pte, pfn_pte(pfn, prot)); 218 } 219 max_pfn_mapped = pfn; 220 } 221 } 222 } 223 224 static inline int page_kills_ppro(unsigned long pagenr) 225 { 226 if (pagenr >= 0x70000 && pagenr <= 0x7003F) 227 return 1; 228 return 0; 229 } 230 231 #ifdef CONFIG_HIGHMEM 232 pte_t *kmap_pte; 233 pgprot_t kmap_prot; 234 235 static inline pte_t *kmap_get_fixmap_pte(unsigned long vaddr) 236 { 237 return pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr), 238 vaddr), vaddr), vaddr); 239 } 240 241 static void __init kmap_init(void) 242 { 243 unsigned long kmap_vstart; 244 245 /* 246 * Cache the first kmap pte: 247 */ 248 kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN); 249 kmap_pte = kmap_get_fixmap_pte(kmap_vstart); 250 251 kmap_prot = PAGE_KERNEL; 252 } 253 254 static void __init permanent_kmaps_init(pgd_t *pgd_base) 255 { 256 unsigned long vaddr; 257 pgd_t *pgd; 258 pud_t *pud; 259 pmd_t *pmd; 260 pte_t *pte; 261 262 vaddr = PKMAP_BASE; 263 page_table_range_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, pgd_base); 264 265 pgd = swapper_pg_dir + pgd_index(vaddr); 266 pud = pud_offset(pgd, vaddr); 267 pmd = pmd_offset(pud, vaddr); 268 pte = pte_offset_kernel(pmd, vaddr); 269 pkmap_page_table = pte; 270 } 271 272 static void __meminit free_new_highpage(struct page *page) 273 { 274 init_page_count(page); 275 __free_page(page); 276 totalhigh_pages++; 277 } 278 279 void __init add_one_highpage_init(struct page *page, int pfn, int bad_ppro) 280 { 281 if (page_is_ram(pfn) && !(bad_ppro && page_kills_ppro(pfn))) { 282 ClearPageReserved(page); 283 free_new_highpage(page); 284 } else 285 SetPageReserved(page); 286 } 287 288 static int __meminit 289 add_one_highpage_hotplug(struct page *page, unsigned long pfn) 290 { 291 free_new_highpage(page); 292 totalram_pages++; 293 #ifdef CONFIG_FLATMEM 294 max_mapnr = max(pfn, max_mapnr); 295 #endif 296 num_physpages++; 297 298 return 0; 299 } 300 301 /* 302 * Not currently handling the NUMA case. 303 * Assuming single node and all memory that 304 * has been added dynamically that would be 305 * onlined here is in HIGHMEM. 306 */ 307 void __meminit online_page(struct page *page) 308 { 309 ClearPageReserved(page); 310 add_one_highpage_hotplug(page, page_to_pfn(page)); 311 } 312 313 #ifndef CONFIG_NUMA 314 static void __init set_highmem_pages_init(int bad_ppro) 315 { 316 int pfn; 317 318 for (pfn = highstart_pfn; pfn < highend_pfn; pfn++) { 319 /* 320 * Holes under sparsemem might not have no mem_map[]: 321 */ 322 if (pfn_valid(pfn)) 323 add_one_highpage_init(pfn_to_page(pfn), pfn, bad_ppro); 324 } 325 totalram_pages += totalhigh_pages; 326 } 327 #endif /* !CONFIG_NUMA */ 328 329 #else 330 # define kmap_init() do { } while (0) 331 # define permanent_kmaps_init(pgd_base) do { } while (0) 332 # define set_highmem_pages_init(bad_ppro) do { } while (0) 333 #endif /* CONFIG_HIGHMEM */ 334 335 pteval_t __PAGE_KERNEL = _PAGE_KERNEL; 336 EXPORT_SYMBOL(__PAGE_KERNEL); 337 338 pteval_t __PAGE_KERNEL_EXEC = _PAGE_KERNEL_EXEC; 339 340 void __init native_pagetable_setup_start(pgd_t *base) 341 { 342 unsigned long pfn, va; 343 pgd_t *pgd; 344 pud_t *pud; 345 pmd_t *pmd; 346 pte_t *pte; 347 348 /* 349 * Remove any mappings which extend past the end of physical 350 * memory from the boot time page table: 351 */ 352 for (pfn = max_low_pfn + 1; pfn < 1<<(32-PAGE_SHIFT); pfn++) { 353 va = PAGE_OFFSET + (pfn<<PAGE_SHIFT); 354 pgd = base + pgd_index(va); 355 if (!pgd_present(*pgd)) 356 break; 357 358 pud = pud_offset(pgd, va); 359 pmd = pmd_offset(pud, va); 360 if (!pmd_present(*pmd)) 361 break; 362 363 pte = pte_offset_kernel(pmd, va); 364 if (!pte_present(*pte)) 365 break; 366 367 pte_clear(NULL, va, pte); 368 } 369 paravirt_alloc_pd(&init_mm, __pa(base) >> PAGE_SHIFT); 370 } 371 372 void __init native_pagetable_setup_done(pgd_t *base) 373 { 374 } 375 376 /* 377 * Build a proper pagetable for the kernel mappings. Up until this 378 * point, we've been running on some set of pagetables constructed by 379 * the boot process. 380 * 381 * If we're booting on native hardware, this will be a pagetable 382 * constructed in arch/x86/kernel/head_32.S. The root of the 383 * pagetable will be swapper_pg_dir. 384 * 385 * If we're booting paravirtualized under a hypervisor, then there are 386 * more options: we may already be running PAE, and the pagetable may 387 * or may not be based in swapper_pg_dir. In any case, 388 * paravirt_pagetable_setup_start() will set up swapper_pg_dir 389 * appropriately for the rest of the initialization to work. 390 * 391 * In general, pagetable_init() assumes that the pagetable may already 392 * be partially populated, and so it avoids stomping on any existing 393 * mappings. 394 */ 395 static void __init pagetable_init(void) 396 { 397 pgd_t *pgd_base = swapper_pg_dir; 398 unsigned long vaddr, end; 399 400 paravirt_pagetable_setup_start(pgd_base); 401 402 /* Enable PSE if available */ 403 if (cpu_has_pse) 404 set_in_cr4(X86_CR4_PSE); 405 406 /* Enable PGE if available */ 407 if (cpu_has_pge) { 408 set_in_cr4(X86_CR4_PGE); 409 __PAGE_KERNEL |= _PAGE_GLOBAL; 410 __PAGE_KERNEL_EXEC |= _PAGE_GLOBAL; 411 } 412 413 kernel_physical_mapping_init(pgd_base); 414 remap_numa_kva(); 415 416 /* 417 * Fixed mappings, only the page table structure has to be 418 * created - mappings will be set by set_fixmap(): 419 */ 420 early_ioremap_clear(); 421 vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK; 422 end = (FIXADDR_TOP + PMD_SIZE - 1) & PMD_MASK; 423 page_table_range_init(vaddr, end, pgd_base); 424 early_ioremap_reset(); 425 426 permanent_kmaps_init(pgd_base); 427 428 paravirt_pagetable_setup_done(pgd_base); 429 } 430 431 #ifdef CONFIG_ACPI_SLEEP 432 /* 433 * ACPI suspend needs this for resume, because things like the intel-agp 434 * driver might have split up a kernel 4MB mapping. 435 */ 436 char swsusp_pg_dir[PAGE_SIZE] 437 __attribute__ ((aligned(PAGE_SIZE))); 438 439 static inline void save_pg_dir(void) 440 { 441 memcpy(swsusp_pg_dir, swapper_pg_dir, PAGE_SIZE); 442 } 443 #else /* !CONFIG_ACPI_SLEEP */ 444 static inline void save_pg_dir(void) 445 { 446 } 447 #endif /* !CONFIG_ACPI_SLEEP */ 448 449 void zap_low_mappings(void) 450 { 451 int i; 452 453 save_pg_dir(); 454 455 /* 456 * Zap initial low-memory mappings. 457 * 458 * Note that "pgd_clear()" doesn't do it for 459 * us, because pgd_clear() is a no-op on i386. 460 */ 461 for (i = 0; i < USER_PTRS_PER_PGD; i++) { 462 #ifdef CONFIG_X86_PAE 463 set_pgd(swapper_pg_dir+i, __pgd(1 + __pa(empty_zero_page))); 464 #else 465 set_pgd(swapper_pg_dir+i, __pgd(0)); 466 #endif 467 } 468 flush_tlb_all(); 469 } 470 471 int nx_enabled; 472 473 pteval_t __supported_pte_mask __read_mostly = ~_PAGE_NX; 474 EXPORT_SYMBOL_GPL(__supported_pte_mask); 475 476 #ifdef CONFIG_X86_PAE 477 478 static int disable_nx __initdata; 479 480 /* 481 * noexec = on|off 482 * 483 * Control non executable mappings. 484 * 485 * on Enable 486 * off Disable 487 */ 488 static int __init noexec_setup(char *str) 489 { 490 if (!str || !strcmp(str, "on")) { 491 if (cpu_has_nx) { 492 __supported_pte_mask |= _PAGE_NX; 493 disable_nx = 0; 494 } 495 } else { 496 if (!strcmp(str, "off")) { 497 disable_nx = 1; 498 __supported_pte_mask &= ~_PAGE_NX; 499 } else { 500 return -EINVAL; 501 } 502 } 503 504 return 0; 505 } 506 early_param("noexec", noexec_setup); 507 508 static void __init set_nx(void) 509 { 510 unsigned int v[4], l, h; 511 512 if (cpu_has_pae && (cpuid_eax(0x80000000) > 0x80000001)) { 513 cpuid(0x80000001, &v[0], &v[1], &v[2], &v[3]); 514 515 if ((v[3] & (1 << 20)) && !disable_nx) { 516 rdmsr(MSR_EFER, l, h); 517 l |= EFER_NX; 518 wrmsr(MSR_EFER, l, h); 519 nx_enabled = 1; 520 __supported_pte_mask |= _PAGE_NX; 521 } 522 } 523 } 524 #endif 525 526 /* 527 * paging_init() sets up the page tables - note that the first 8MB are 528 * already mapped by head.S. 529 * 530 * This routines also unmaps the page at virtual kernel address 0, so 531 * that we can trap those pesky NULL-reference errors in the kernel. 532 */ 533 void __init paging_init(void) 534 { 535 #ifdef CONFIG_X86_PAE 536 set_nx(); 537 if (nx_enabled) 538 printk(KERN_INFO "NX (Execute Disable) protection: active\n"); 539 #endif 540 pagetable_init(); 541 542 load_cr3(swapper_pg_dir); 543 544 __flush_tlb_all(); 545 546 kmap_init(); 547 } 548 549 /* 550 * Test if the WP bit works in supervisor mode. It isn't supported on 386's 551 * and also on some strange 486's (NexGen etc.). All 586+'s are OK. This 552 * used to involve black magic jumps to work around some nasty CPU bugs, 553 * but fortunately the switch to using exceptions got rid of all that. 554 */ 555 static void __init test_wp_bit(void) 556 { 557 printk(KERN_INFO 558 "Checking if this processor honours the WP bit even in supervisor mode..."); 559 560 /* Any page-aligned address will do, the test is non-destructive */ 561 __set_fixmap(FIX_WP_TEST, __pa(&swapper_pg_dir), PAGE_READONLY); 562 boot_cpu_data.wp_works_ok = do_test_wp_bit(); 563 clear_fixmap(FIX_WP_TEST); 564 565 if (!boot_cpu_data.wp_works_ok) { 566 printk(KERN_CONT "No.\n"); 567 #ifdef CONFIG_X86_WP_WORKS_OK 568 panic( 569 "This kernel doesn't support CPU's with broken WP. Recompile it for a 386!"); 570 #endif 571 } else { 572 printk(KERN_CONT "Ok.\n"); 573 } 574 } 575 576 static struct kcore_list kcore_mem, kcore_vmalloc; 577 578 void __init mem_init(void) 579 { 580 int codesize, reservedpages, datasize, initsize; 581 int tmp, bad_ppro; 582 583 #ifdef CONFIG_FLATMEM 584 BUG_ON(!mem_map); 585 #endif 586 bad_ppro = ppro_with_ram_bug(); 587 588 #ifdef CONFIG_HIGHMEM 589 /* check that fixmap and pkmap do not overlap */ 590 if (PKMAP_BASE + LAST_PKMAP*PAGE_SIZE >= FIXADDR_START) { 591 printk(KERN_ERR 592 "fixmap and kmap areas overlap - this will crash\n"); 593 printk(KERN_ERR "pkstart: %lxh pkend: %lxh fixstart %lxh\n", 594 PKMAP_BASE, PKMAP_BASE + LAST_PKMAP*PAGE_SIZE, 595 FIXADDR_START); 596 BUG(); 597 } 598 #endif 599 /* this will put all low memory onto the freelists */ 600 totalram_pages += free_all_bootmem(); 601 602 reservedpages = 0; 603 for (tmp = 0; tmp < max_low_pfn; tmp++) 604 /* 605 * Only count reserved RAM pages: 606 */ 607 if (page_is_ram(tmp) && PageReserved(pfn_to_page(tmp))) 608 reservedpages++; 609 610 set_highmem_pages_init(bad_ppro); 611 612 codesize = (unsigned long) &_etext - (unsigned long) &_text; 613 datasize = (unsigned long) &_edata - (unsigned long) &_etext; 614 initsize = (unsigned long) &__init_end - (unsigned long) &__init_begin; 615 616 kclist_add(&kcore_mem, __va(0), max_low_pfn << PAGE_SHIFT); 617 kclist_add(&kcore_vmalloc, (void *)VMALLOC_START, 618 VMALLOC_END-VMALLOC_START); 619 620 printk(KERN_INFO "Memory: %luk/%luk available (%dk kernel code, " 621 "%dk reserved, %dk data, %dk init, %ldk highmem)\n", 622 (unsigned long) nr_free_pages() << (PAGE_SHIFT-10), 623 num_physpages << (PAGE_SHIFT-10), 624 codesize >> 10, 625 reservedpages << (PAGE_SHIFT-10), 626 datasize >> 10, 627 initsize >> 10, 628 (unsigned long) (totalhigh_pages << (PAGE_SHIFT-10)) 629 ); 630 631 #if 1 /* double-sanity-check paranoia */ 632 printk(KERN_INFO "virtual kernel memory layout:\n" 633 " fixmap : 0x%08lx - 0x%08lx (%4ld kB)\n" 634 #ifdef CONFIG_HIGHMEM 635 " pkmap : 0x%08lx - 0x%08lx (%4ld kB)\n" 636 #endif 637 " vmalloc : 0x%08lx - 0x%08lx (%4ld MB)\n" 638 " lowmem : 0x%08lx - 0x%08lx (%4ld MB)\n" 639 " .init : 0x%08lx - 0x%08lx (%4ld kB)\n" 640 " .data : 0x%08lx - 0x%08lx (%4ld kB)\n" 641 " .text : 0x%08lx - 0x%08lx (%4ld kB)\n", 642 FIXADDR_START, FIXADDR_TOP, 643 (FIXADDR_TOP - FIXADDR_START) >> 10, 644 645 #ifdef CONFIG_HIGHMEM 646 PKMAP_BASE, PKMAP_BASE+LAST_PKMAP*PAGE_SIZE, 647 (LAST_PKMAP*PAGE_SIZE) >> 10, 648 #endif 649 650 VMALLOC_START, VMALLOC_END, 651 (VMALLOC_END - VMALLOC_START) >> 20, 652 653 (unsigned long)__va(0), (unsigned long)high_memory, 654 ((unsigned long)high_memory - (unsigned long)__va(0)) >> 20, 655 656 (unsigned long)&__init_begin, (unsigned long)&__init_end, 657 ((unsigned long)&__init_end - 658 (unsigned long)&__init_begin) >> 10, 659 660 (unsigned long)&_etext, (unsigned long)&_edata, 661 ((unsigned long)&_edata - (unsigned long)&_etext) >> 10, 662 663 (unsigned long)&_text, (unsigned long)&_etext, 664 ((unsigned long)&_etext - (unsigned long)&_text) >> 10); 665 666 #ifdef CONFIG_HIGHMEM 667 BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE > FIXADDR_START); 668 BUG_ON(VMALLOC_END > PKMAP_BASE); 669 #endif 670 BUG_ON(VMALLOC_START > VMALLOC_END); 671 BUG_ON((unsigned long)high_memory > VMALLOC_START); 672 #endif /* double-sanity-check paranoia */ 673 674 if (boot_cpu_data.wp_works_ok < 0) 675 test_wp_bit(); 676 677 cpa_init(); 678 679 /* 680 * Subtle. SMP is doing it's boot stuff late (because it has to 681 * fork idle threads) - but it also needs low mappings for the 682 * protected-mode entry to work. We zap these entries only after 683 * the WP-bit has been tested. 684 */ 685 #ifndef CONFIG_SMP 686 zap_low_mappings(); 687 #endif 688 } 689 690 #ifdef CONFIG_MEMORY_HOTPLUG 691 int arch_add_memory(int nid, u64 start, u64 size) 692 { 693 struct pglist_data *pgdata = NODE_DATA(nid); 694 struct zone *zone = pgdata->node_zones + ZONE_HIGHMEM; 695 unsigned long start_pfn = start >> PAGE_SHIFT; 696 unsigned long nr_pages = size >> PAGE_SHIFT; 697 698 return __add_pages(zone, start_pfn, nr_pages); 699 } 700 #endif 701 702 /* 703 * This function cannot be __init, since exceptions don't work in that 704 * section. Put this after the callers, so that it cannot be inlined. 705 */ 706 static noinline int do_test_wp_bit(void) 707 { 708 char tmp_reg; 709 int flag; 710 711 __asm__ __volatile__( 712 " movb %0, %1 \n" 713 "1: movb %1, %0 \n" 714 " xorl %2, %2 \n" 715 "2: \n" 716 _ASM_EXTABLE(1b,2b) 717 :"=m" (*(char *)fix_to_virt(FIX_WP_TEST)), 718 "=q" (tmp_reg), 719 "=r" (flag) 720 :"2" (1) 721 :"memory"); 722 723 return flag; 724 } 725 726 #ifdef CONFIG_DEBUG_RODATA 727 const int rodata_test_data = 0xC3; 728 EXPORT_SYMBOL_GPL(rodata_test_data); 729 730 void mark_rodata_ro(void) 731 { 732 unsigned long start = PFN_ALIGN(_text); 733 unsigned long size = PFN_ALIGN(_etext) - start; 734 735 set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT); 736 printk(KERN_INFO "Write protecting the kernel text: %luk\n", 737 size >> 10); 738 739 #ifdef CONFIG_CPA_DEBUG 740 printk(KERN_INFO "Testing CPA: Reverting %lx-%lx\n", 741 start, start+size); 742 set_pages_rw(virt_to_page(start), size>>PAGE_SHIFT); 743 744 printk(KERN_INFO "Testing CPA: write protecting again\n"); 745 set_pages_ro(virt_to_page(start), size>>PAGE_SHIFT); 746 #endif 747 start += size; 748 size = (unsigned long)__end_rodata - start; 749 set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT); 750 printk(KERN_INFO "Write protecting the kernel read-only data: %luk\n", 751 size >> 10); 752 rodata_test(); 753 754 #ifdef CONFIG_CPA_DEBUG 755 printk(KERN_INFO "Testing CPA: undo %lx-%lx\n", 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 763 764 void free_init_pages(char *what, unsigned long begin, unsigned long end) 765 { 766 #ifdef CONFIG_DEBUG_PAGEALLOC 767 /* 768 * If debugging page accesses then do not free this memory but 769 * mark them not present - any buggy init-section access will 770 * create a kernel page fault: 771 */ 772 printk(KERN_INFO "debug: unmapping init memory %08lx..%08lx\n", 773 begin, PAGE_ALIGN(end)); 774 set_memory_np(begin, (end - begin) >> PAGE_SHIFT); 775 #else 776 unsigned long addr; 777 778 /* 779 * We just marked the kernel text read only above, now that 780 * we are going to free part of that, we need to make that 781 * writeable first. 782 */ 783 set_memory_rw(begin, (end - begin) >> PAGE_SHIFT); 784 785 for (addr = begin; addr < end; addr += PAGE_SIZE) { 786 ClearPageReserved(virt_to_page(addr)); 787 init_page_count(virt_to_page(addr)); 788 memset((void *)addr, POISON_FREE_INITMEM, PAGE_SIZE); 789 free_page(addr); 790 totalram_pages++; 791 } 792 printk(KERN_INFO "Freeing %s: %luk freed\n", what, (end - begin) >> 10); 793 #endif 794 } 795 796 void free_initmem(void) 797 { 798 free_init_pages("unused kernel memory", 799 (unsigned long)(&__init_begin), 800 (unsigned long)(&__init_end)); 801 } 802 803 #ifdef CONFIG_BLK_DEV_INITRD 804 void free_initrd_mem(unsigned long start, unsigned long end) 805 { 806 free_init_pages("initrd memory", start, end); 807 } 808 #endif 809