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 static void __init add_one_highpage_init(struct page *page) 431 { 432 ClearPageReserved(page); 433 init_page_count(page); 434 __free_page(page); 435 totalhigh_pages++; 436 } 437 438 void __init add_highpages_with_active_regions(int nid, 439 unsigned long start_pfn, unsigned long end_pfn) 440 { 441 phys_addr_t start, end; 442 u64 i; 443 444 for_each_free_mem_range(i, nid, &start, &end, NULL) { 445 unsigned long pfn = clamp_t(unsigned long, PFN_UP(start), 446 start_pfn, end_pfn); 447 unsigned long e_pfn = clamp_t(unsigned long, PFN_DOWN(end), 448 start_pfn, end_pfn); 449 for ( ; pfn < e_pfn; pfn++) 450 if (pfn_valid(pfn)) 451 add_one_highpage_init(pfn_to_page(pfn)); 452 } 453 } 454 #else 455 static inline void permanent_kmaps_init(pgd_t *pgd_base) 456 { 457 } 458 #endif /* CONFIG_HIGHMEM */ 459 460 void __init native_pagetable_init(void) 461 { 462 unsigned long pfn, va; 463 pgd_t *pgd, *base = swapper_pg_dir; 464 pud_t *pud; 465 pmd_t *pmd; 466 pte_t *pte; 467 468 /* 469 * Remove any mappings which extend past the end of physical 470 * memory from the boot time page table. 471 * In virtual address space, we should have at least two pages 472 * from VMALLOC_END to pkmap or fixmap according to VMALLOC_END 473 * definition. And max_low_pfn is set to VMALLOC_END physical 474 * address. If initial memory mapping is doing right job, we 475 * should have pte used near max_low_pfn or one pmd is not present. 476 */ 477 for (pfn = max_low_pfn; pfn < 1<<(32-PAGE_SHIFT); pfn++) { 478 va = PAGE_OFFSET + (pfn<<PAGE_SHIFT); 479 pgd = base + pgd_index(va); 480 if (!pgd_present(*pgd)) 481 break; 482 483 pud = pud_offset(pgd, va); 484 pmd = pmd_offset(pud, va); 485 if (!pmd_present(*pmd)) 486 break; 487 488 /* should not be large page here */ 489 if (pmd_large(*pmd)) { 490 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", 491 pfn, pmd, __pa(pmd)); 492 BUG_ON(1); 493 } 494 495 pte = pte_offset_kernel(pmd, va); 496 if (!pte_present(*pte)) 497 break; 498 499 printk(KERN_DEBUG "clearing pte for ram above max_low_pfn: pfn: %lx pmd: %p pmd phys: %lx pte: %p pte phys: %lx\n", 500 pfn, pmd, __pa(pmd), pte, __pa(pte)); 501 pte_clear(NULL, va, pte); 502 } 503 paravirt_alloc_pmd(&init_mm, __pa(base) >> PAGE_SHIFT); 504 paging_init(); 505 } 506 507 /* 508 * Build a proper pagetable for the kernel mappings. Up until this 509 * point, we've been running on some set of pagetables constructed by 510 * the boot process. 511 * 512 * If we're booting on native hardware, this will be a pagetable 513 * constructed in arch/x86/kernel/head_32.S. The root of the 514 * pagetable will be swapper_pg_dir. 515 * 516 * If we're booting paravirtualized under a hypervisor, then there are 517 * more options: we may already be running PAE, and the pagetable may 518 * or may not be based in swapper_pg_dir. In any case, 519 * paravirt_pagetable_init() will set up swapper_pg_dir 520 * appropriately for the rest of the initialization to work. 521 * 522 * In general, pagetable_init() assumes that the pagetable may already 523 * be partially populated, and so it avoids stomping on any existing 524 * mappings. 525 */ 526 void __init early_ioremap_page_table_range_init(void) 527 { 528 pgd_t *pgd_base = swapper_pg_dir; 529 unsigned long vaddr, end; 530 531 /* 532 * Fixed mappings, only the page table structure has to be 533 * created - mappings will be set by set_fixmap(): 534 */ 535 vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK; 536 end = (FIXADDR_TOP + PMD_SIZE - 1) & PMD_MASK; 537 page_table_range_init(vaddr, end, pgd_base); 538 early_ioremap_reset(); 539 } 540 541 static void __init pagetable_init(void) 542 { 543 pgd_t *pgd_base = swapper_pg_dir; 544 545 permanent_kmaps_init(pgd_base); 546 } 547 548 pteval_t __supported_pte_mask __read_mostly = ~(_PAGE_NX | _PAGE_GLOBAL | _PAGE_IOMAP); 549 EXPORT_SYMBOL_GPL(__supported_pte_mask); 550 551 /* user-defined highmem size */ 552 static unsigned int highmem_pages = -1; 553 554 /* 555 * highmem=size forces highmem to be exactly 'size' bytes. 556 * This works even on boxes that have no highmem otherwise. 557 * This also works to reduce highmem size on bigger boxes. 558 */ 559 static int __init parse_highmem(char *arg) 560 { 561 if (!arg) 562 return -EINVAL; 563 564 highmem_pages = memparse(arg, &arg) >> PAGE_SHIFT; 565 return 0; 566 } 567 early_param("highmem", parse_highmem); 568 569 #define MSG_HIGHMEM_TOO_BIG \ 570 "highmem size (%luMB) is bigger than pages available (%luMB)!\n" 571 572 #define MSG_LOWMEM_TOO_SMALL \ 573 "highmem size (%luMB) results in <64MB lowmem, ignoring it!\n" 574 /* 575 * All of RAM fits into lowmem - but if user wants highmem 576 * artificially via the highmem=x boot parameter then create 577 * it: 578 */ 579 static void __init lowmem_pfn_init(void) 580 { 581 /* max_low_pfn is 0, we already have early_res support */ 582 max_low_pfn = max_pfn; 583 584 if (highmem_pages == -1) 585 highmem_pages = 0; 586 #ifdef CONFIG_HIGHMEM 587 if (highmem_pages >= max_pfn) { 588 printk(KERN_ERR MSG_HIGHMEM_TOO_BIG, 589 pages_to_mb(highmem_pages), pages_to_mb(max_pfn)); 590 highmem_pages = 0; 591 } 592 if (highmem_pages) { 593 if (max_low_pfn - highmem_pages < 64*1024*1024/PAGE_SIZE) { 594 printk(KERN_ERR MSG_LOWMEM_TOO_SMALL, 595 pages_to_mb(highmem_pages)); 596 highmem_pages = 0; 597 } 598 max_low_pfn -= highmem_pages; 599 } 600 #else 601 if (highmem_pages) 602 printk(KERN_ERR "ignoring highmem size on non-highmem kernel!\n"); 603 #endif 604 } 605 606 #define MSG_HIGHMEM_TOO_SMALL \ 607 "only %luMB highmem pages available, ignoring highmem size of %luMB!\n" 608 609 #define MSG_HIGHMEM_TRIMMED \ 610 "Warning: only 4GB will be used. Use a HIGHMEM64G enabled kernel!\n" 611 /* 612 * We have more RAM than fits into lowmem - we try to put it into 613 * highmem, also taking the highmem=x boot parameter into account: 614 */ 615 static void __init highmem_pfn_init(void) 616 { 617 max_low_pfn = MAXMEM_PFN; 618 619 if (highmem_pages == -1) 620 highmem_pages = max_pfn - MAXMEM_PFN; 621 622 if (highmem_pages + MAXMEM_PFN < max_pfn) 623 max_pfn = MAXMEM_PFN + highmem_pages; 624 625 if (highmem_pages + MAXMEM_PFN > max_pfn) { 626 printk(KERN_WARNING MSG_HIGHMEM_TOO_SMALL, 627 pages_to_mb(max_pfn - MAXMEM_PFN), 628 pages_to_mb(highmem_pages)); 629 highmem_pages = 0; 630 } 631 #ifndef CONFIG_HIGHMEM 632 /* Maximum memory usable is what is directly addressable */ 633 printk(KERN_WARNING "Warning only %ldMB will be used.\n", MAXMEM>>20); 634 if (max_pfn > MAX_NONPAE_PFN) 635 printk(KERN_WARNING "Use a HIGHMEM64G enabled kernel.\n"); 636 else 637 printk(KERN_WARNING "Use a HIGHMEM enabled kernel.\n"); 638 max_pfn = MAXMEM_PFN; 639 #else /* !CONFIG_HIGHMEM */ 640 #ifndef CONFIG_HIGHMEM64G 641 if (max_pfn > MAX_NONPAE_PFN) { 642 max_pfn = MAX_NONPAE_PFN; 643 printk(KERN_WARNING MSG_HIGHMEM_TRIMMED); 644 } 645 #endif /* !CONFIG_HIGHMEM64G */ 646 #endif /* !CONFIG_HIGHMEM */ 647 } 648 649 /* 650 * Determine low and high memory ranges: 651 */ 652 void __init find_low_pfn_range(void) 653 { 654 /* it could update max_pfn */ 655 656 if (max_pfn <= MAXMEM_PFN) 657 lowmem_pfn_init(); 658 else 659 highmem_pfn_init(); 660 } 661 662 #ifndef CONFIG_NEED_MULTIPLE_NODES 663 void __init initmem_init(void) 664 { 665 #ifdef CONFIG_HIGHMEM 666 highstart_pfn = highend_pfn = max_pfn; 667 if (max_pfn > max_low_pfn) 668 highstart_pfn = max_low_pfn; 669 printk(KERN_NOTICE "%ldMB HIGHMEM available.\n", 670 pages_to_mb(highend_pfn - highstart_pfn)); 671 num_physpages = highend_pfn; 672 high_memory = (void *) __va(highstart_pfn * PAGE_SIZE - 1) + 1; 673 #else 674 num_physpages = max_low_pfn; 675 high_memory = (void *) __va(max_low_pfn * PAGE_SIZE - 1) + 1; 676 #endif 677 678 memblock_set_node(0, (phys_addr_t)ULLONG_MAX, 0); 679 sparse_memory_present_with_active_regions(0); 680 681 #ifdef CONFIG_FLATMEM 682 max_mapnr = num_physpages; 683 #endif 684 __vmalloc_start_set = true; 685 686 printk(KERN_NOTICE "%ldMB LOWMEM available.\n", 687 pages_to_mb(max_low_pfn)); 688 689 setup_bootmem_allocator(); 690 } 691 #endif /* !CONFIG_NEED_MULTIPLE_NODES */ 692 693 void __init setup_bootmem_allocator(void) 694 { 695 printk(KERN_INFO " mapped low ram: 0 - %08lx\n", 696 max_pfn_mapped<<PAGE_SHIFT); 697 printk(KERN_INFO " low ram: 0 - %08lx\n", max_low_pfn<<PAGE_SHIFT); 698 } 699 700 /* 701 * paging_init() sets up the page tables - note that the first 8MB are 702 * already mapped by head.S. 703 * 704 * This routines also unmaps the page at virtual kernel address 0, so 705 * that we can trap those pesky NULL-reference errors in the kernel. 706 */ 707 void __init paging_init(void) 708 { 709 pagetable_init(); 710 711 __flush_tlb_all(); 712 713 kmap_init(); 714 715 /* 716 * NOTE: at this point the bootmem allocator is fully available. 717 */ 718 olpc_dt_build_devicetree(); 719 sparse_memory_present_with_active_regions(MAX_NUMNODES); 720 sparse_init(); 721 zone_sizes_init(); 722 } 723 724 /* 725 * Test if the WP bit works in supervisor mode. It isn't supported on 386's 726 * and also on some strange 486's. All 586+'s are OK. This used to involve 727 * black magic jumps to work around some nasty CPU bugs, but fortunately the 728 * switch to using exceptions got rid of all that. 729 */ 730 static void __init test_wp_bit(void) 731 { 732 printk(KERN_INFO 733 "Checking if this processor honours the WP bit even in supervisor mode..."); 734 735 /* Any page-aligned address will do, the test is non-destructive */ 736 __set_fixmap(FIX_WP_TEST, __pa(&swapper_pg_dir), PAGE_KERNEL_RO); 737 boot_cpu_data.wp_works_ok = do_test_wp_bit(); 738 clear_fixmap(FIX_WP_TEST); 739 740 if (!boot_cpu_data.wp_works_ok) { 741 printk(KERN_CONT "No.\n"); 742 panic("Linux doesn't support CPUs with broken WP."); 743 } else { 744 printk(KERN_CONT "Ok.\n"); 745 } 746 } 747 748 void __init mem_init(void) 749 { 750 int codesize, reservedpages, datasize, initsize; 751 int tmp; 752 753 pci_iommu_alloc(); 754 755 #ifdef CONFIG_FLATMEM 756 BUG_ON(!mem_map); 757 #endif 758 /* 759 * With CONFIG_DEBUG_PAGEALLOC initialization of highmem pages has to 760 * be done before free_all_bootmem(). Memblock use free low memory for 761 * temporary data (see find_range_array()) and for this purpose can use 762 * pages that was already passed to the buddy allocator, hence marked as 763 * not accessible in the page tables when compiled with 764 * CONFIG_DEBUG_PAGEALLOC. Otherwise order of initialization is not 765 * important here. 766 */ 767 set_highmem_pages_init(); 768 769 /* this will put all low memory onto the freelists */ 770 totalram_pages += free_all_bootmem(); 771 772 reservedpages = 0; 773 for (tmp = 0; tmp < max_low_pfn; tmp++) 774 /* 775 * Only count reserved RAM pages: 776 */ 777 if (page_is_ram(tmp) && PageReserved(pfn_to_page(tmp))) 778 reservedpages++; 779 780 after_bootmem = 1; 781 782 codesize = (unsigned long) &_etext - (unsigned long) &_text; 783 datasize = (unsigned long) &_edata - (unsigned long) &_etext; 784 initsize = (unsigned long) &__init_end - (unsigned long) &__init_begin; 785 786 printk(KERN_INFO "Memory: %luk/%luk available (%dk kernel code, " 787 "%dk reserved, %dk data, %dk init, %ldk highmem)\n", 788 nr_free_pages() << (PAGE_SHIFT-10), 789 num_physpages << (PAGE_SHIFT-10), 790 codesize >> 10, 791 reservedpages << (PAGE_SHIFT-10), 792 datasize >> 10, 793 initsize >> 10, 794 totalhigh_pages << (PAGE_SHIFT-10)); 795 796 printk(KERN_INFO "virtual kernel memory layout:\n" 797 " fixmap : 0x%08lx - 0x%08lx (%4ld kB)\n" 798 #ifdef CONFIG_HIGHMEM 799 " pkmap : 0x%08lx - 0x%08lx (%4ld kB)\n" 800 #endif 801 " vmalloc : 0x%08lx - 0x%08lx (%4ld MB)\n" 802 " lowmem : 0x%08lx - 0x%08lx (%4ld MB)\n" 803 " .init : 0x%08lx - 0x%08lx (%4ld kB)\n" 804 " .data : 0x%08lx - 0x%08lx (%4ld kB)\n" 805 " .text : 0x%08lx - 0x%08lx (%4ld kB)\n", 806 FIXADDR_START, FIXADDR_TOP, 807 (FIXADDR_TOP - FIXADDR_START) >> 10, 808 809 #ifdef CONFIG_HIGHMEM 810 PKMAP_BASE, PKMAP_BASE+LAST_PKMAP*PAGE_SIZE, 811 (LAST_PKMAP*PAGE_SIZE) >> 10, 812 #endif 813 814 VMALLOC_START, VMALLOC_END, 815 (VMALLOC_END - VMALLOC_START) >> 20, 816 817 (unsigned long)__va(0), (unsigned long)high_memory, 818 ((unsigned long)high_memory - (unsigned long)__va(0)) >> 20, 819 820 (unsigned long)&__init_begin, (unsigned long)&__init_end, 821 ((unsigned long)&__init_end - 822 (unsigned long)&__init_begin) >> 10, 823 824 (unsigned long)&_etext, (unsigned long)&_edata, 825 ((unsigned long)&_edata - (unsigned long)&_etext) >> 10, 826 827 (unsigned long)&_text, (unsigned long)&_etext, 828 ((unsigned long)&_etext - (unsigned long)&_text) >> 10); 829 830 /* 831 * Check boundaries twice: Some fundamental inconsistencies can 832 * be detected at build time already. 833 */ 834 #define __FIXADDR_TOP (-PAGE_SIZE) 835 #ifdef CONFIG_HIGHMEM 836 BUILD_BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE > FIXADDR_START); 837 BUILD_BUG_ON(VMALLOC_END > PKMAP_BASE); 838 #endif 839 #define high_memory (-128UL << 20) 840 BUILD_BUG_ON(VMALLOC_START >= VMALLOC_END); 841 #undef high_memory 842 #undef __FIXADDR_TOP 843 844 #ifdef CONFIG_HIGHMEM 845 BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE > FIXADDR_START); 846 BUG_ON(VMALLOC_END > PKMAP_BASE); 847 #endif 848 BUG_ON(VMALLOC_START >= VMALLOC_END); 849 BUG_ON((unsigned long)high_memory > VMALLOC_START); 850 851 if (boot_cpu_data.wp_works_ok < 0) 852 test_wp_bit(); 853 } 854 855 #ifdef CONFIG_MEMORY_HOTPLUG 856 int arch_add_memory(int nid, u64 start, u64 size) 857 { 858 struct pglist_data *pgdata = NODE_DATA(nid); 859 struct zone *zone = pgdata->node_zones + ZONE_HIGHMEM; 860 unsigned long start_pfn = start >> PAGE_SHIFT; 861 unsigned long nr_pages = size >> PAGE_SHIFT; 862 863 return __add_pages(nid, zone, start_pfn, nr_pages); 864 } 865 866 #ifdef CONFIG_MEMORY_HOTREMOVE 867 int arch_remove_memory(u64 start, u64 size) 868 { 869 unsigned long start_pfn = start >> PAGE_SHIFT; 870 unsigned long nr_pages = size >> PAGE_SHIFT; 871 struct zone *zone; 872 873 zone = page_zone(pfn_to_page(start_pfn)); 874 return __remove_pages(zone, start_pfn, nr_pages); 875 } 876 #endif 877 #endif 878 879 /* 880 * This function cannot be __init, since exceptions don't work in that 881 * section. Put this after the callers, so that it cannot be inlined. 882 */ 883 static noinline int do_test_wp_bit(void) 884 { 885 char tmp_reg; 886 int flag; 887 888 __asm__ __volatile__( 889 " movb %0, %1 \n" 890 "1: movb %1, %0 \n" 891 " xorl %2, %2 \n" 892 "2: \n" 893 _ASM_EXTABLE(1b,2b) 894 :"=m" (*(char *)fix_to_virt(FIX_WP_TEST)), 895 "=q" (tmp_reg), 896 "=r" (flag) 897 :"2" (1) 898 :"memory"); 899 900 return flag; 901 } 902 903 #ifdef CONFIG_DEBUG_RODATA 904 const int rodata_test_data = 0xC3; 905 EXPORT_SYMBOL_GPL(rodata_test_data); 906 907 int kernel_set_to_readonly __read_mostly; 908 909 void set_kernel_text_rw(void) 910 { 911 unsigned long start = PFN_ALIGN(_text); 912 unsigned long size = PFN_ALIGN(_etext) - start; 913 914 if (!kernel_set_to_readonly) 915 return; 916 917 pr_debug("Set kernel text: %lx - %lx for read write\n", 918 start, start+size); 919 920 set_pages_rw(virt_to_page(start), size >> PAGE_SHIFT); 921 } 922 923 void set_kernel_text_ro(void) 924 { 925 unsigned long start = PFN_ALIGN(_text); 926 unsigned long size = PFN_ALIGN(_etext) - start; 927 928 if (!kernel_set_to_readonly) 929 return; 930 931 pr_debug("Set kernel text: %lx - %lx for read only\n", 932 start, start+size); 933 934 set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT); 935 } 936 937 static void mark_nxdata_nx(void) 938 { 939 /* 940 * When this called, init has already been executed and released, 941 * so everything past _etext should be NX. 942 */ 943 unsigned long start = PFN_ALIGN(_etext); 944 /* 945 * This comes from is_kernel_text upper limit. Also HPAGE where used: 946 */ 947 unsigned long size = (((unsigned long)__init_end + HPAGE_SIZE) & HPAGE_MASK) - start; 948 949 if (__supported_pte_mask & _PAGE_NX) 950 printk(KERN_INFO "NX-protecting the kernel data: %luk\n", size >> 10); 951 set_pages_nx(virt_to_page(start), size >> PAGE_SHIFT); 952 } 953 954 void mark_rodata_ro(void) 955 { 956 unsigned long start = PFN_ALIGN(_text); 957 unsigned long size = PFN_ALIGN(_etext) - start; 958 959 set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT); 960 printk(KERN_INFO "Write protecting the kernel text: %luk\n", 961 size >> 10); 962 963 kernel_set_to_readonly = 1; 964 965 #ifdef CONFIG_CPA_DEBUG 966 printk(KERN_INFO "Testing CPA: Reverting %lx-%lx\n", 967 start, start+size); 968 set_pages_rw(virt_to_page(start), size>>PAGE_SHIFT); 969 970 printk(KERN_INFO "Testing CPA: write protecting again\n"); 971 set_pages_ro(virt_to_page(start), size>>PAGE_SHIFT); 972 #endif 973 974 start += size; 975 size = (unsigned long)__end_rodata - start; 976 set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT); 977 printk(KERN_INFO "Write protecting the kernel read-only data: %luk\n", 978 size >> 10); 979 rodata_test(); 980 981 #ifdef CONFIG_CPA_DEBUG 982 printk(KERN_INFO "Testing CPA: undo %lx-%lx\n", start, start + size); 983 set_pages_rw(virt_to_page(start), size >> PAGE_SHIFT); 984 985 printk(KERN_INFO "Testing CPA: write protecting again\n"); 986 set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT); 987 #endif 988 mark_nxdata_nx(); 989 } 990 #endif 991 992