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/signal.h> 9 #include <linux/sched.h> 10 #include <linux/kernel.h> 11 #include <linux/errno.h> 12 #include <linux/string.h> 13 #include <linux/types.h> 14 #include <linux/ptrace.h> 15 #include <linux/mman.h> 16 #include <linux/mm.h> 17 #include <linux/hugetlb.h> 18 #include <linux/swap.h> 19 #include <linux/smp.h> 20 #include <linux/init.h> 21 #include <linux/highmem.h> 22 #include <linux/pagemap.h> 23 #include <linux/pci.h> 24 #include <linux/pfn.h> 25 #include <linux/poison.h> 26 #include <linux/memblock.h> 27 #include <linux/proc_fs.h> 28 #include <linux/memory_hotplug.h> 29 #include <linux/initrd.h> 30 #include <linux/cpumask.h> 31 #include <linux/gfp.h> 32 33 #include <asm/asm.h> 34 #include <asm/bios_ebda.h> 35 #include <asm/processor.h> 36 #include <linux/uaccess.h> 37 #include <asm/pgtable.h> 38 #include <asm/dma.h> 39 #include <asm/fixmap.h> 40 #include <asm/e820/api.h> 41 #include <asm/apic.h> 42 #include <asm/bugs.h> 43 #include <asm/tlb.h> 44 #include <asm/tlbflush.h> 45 #include <asm/olpc_ofw.h> 46 #include <asm/pgalloc.h> 47 #include <asm/sections.h> 48 #include <asm/paravirt.h> 49 #include <asm/setup.h> 50 #include <asm/set_memory.h> 51 #include <asm/page_types.h> 52 #include <asm/cpu_entry_area.h> 53 #include <asm/init.h> 54 55 #include "mm_internal.h" 56 57 unsigned long highstart_pfn, highend_pfn; 58 59 bool __read_mostly __vmalloc_start_set = false; 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 p4d_t *p4d; 69 pud_t *pud; 70 pmd_t *pmd_table; 71 72 #ifdef CONFIG_X86_PAE 73 if (!(pgd_val(*pgd) & _PAGE_PRESENT)) { 74 pmd_table = (pmd_t *)alloc_low_page(); 75 paravirt_alloc_pmd(&init_mm, __pa(pmd_table) >> PAGE_SHIFT); 76 set_pgd(pgd, __pgd(__pa(pmd_table) | _PAGE_PRESENT)); 77 p4d = p4d_offset(pgd, 0); 78 pud = pud_offset(p4d, 0); 79 BUG_ON(pmd_table != pmd_offset(pud, 0)); 80 81 return pmd_table; 82 } 83 #endif 84 p4d = p4d_offset(pgd, 0); 85 pud = pud_offset(p4d, 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 pmd_idx = pmd_index(vaddr); 141 142 for ( ; (pgd_idx < PTRS_PER_PGD) && (vaddr != end); pgd_idx++) { 143 for (; (pmd_idx < PTRS_PER_PMD) && (vaddr != end); 144 pmd_idx++) { 145 if ((vaddr >> PMD_SHIFT) >= pmd_idx_kmap_begin && 146 (vaddr >> PMD_SHIFT) <= pmd_idx_kmap_end) 147 count++; 148 vaddr += PMD_SIZE; 149 } 150 pmd_idx = 0; 151 } 152 #endif 153 return count; 154 } 155 156 static pte_t *__init page_table_kmap_check(pte_t *pte, pmd_t *pmd, 157 unsigned long vaddr, pte_t *lastpte, 158 void **adr) 159 { 160 #ifdef CONFIG_HIGHMEM 161 /* 162 * Something (early fixmap) may already have put a pte 163 * page here, which causes the page table allocation 164 * to become nonlinear. Attempt to fix it, and if it 165 * is still nonlinear then we have to bug. 166 */ 167 int pmd_idx_kmap_begin = fix_to_virt(FIX_KMAP_END) >> PMD_SHIFT; 168 int pmd_idx_kmap_end = fix_to_virt(FIX_KMAP_BEGIN) >> PMD_SHIFT; 169 170 if (pmd_idx_kmap_begin != pmd_idx_kmap_end 171 && (vaddr >> PMD_SHIFT) >= pmd_idx_kmap_begin 172 && (vaddr >> PMD_SHIFT) <= pmd_idx_kmap_end) { 173 pte_t *newpte; 174 int i; 175 176 BUG_ON(after_bootmem); 177 newpte = *adr; 178 for (i = 0; i < PTRS_PER_PTE; i++) 179 set_pte(newpte + i, pte[i]); 180 *adr = (void *)(((unsigned long)(*adr)) + PAGE_SIZE); 181 182 paravirt_alloc_pte(&init_mm, __pa(newpte) >> PAGE_SHIFT); 183 set_pmd(pmd, __pmd(__pa(newpte)|_PAGE_TABLE)); 184 BUG_ON(newpte != pte_offset_kernel(pmd, 0)); 185 __flush_tlb_all(); 186 187 paravirt_release_pte(__pa(pte) >> PAGE_SHIFT); 188 pte = newpte; 189 } 190 BUG_ON(vaddr < fix_to_virt(FIX_KMAP_BEGIN - 1) 191 && vaddr > fix_to_virt(FIX_KMAP_END) 192 && lastpte && lastpte + PTRS_PER_PTE != pte); 193 #endif 194 return pte; 195 } 196 197 /* 198 * This function initializes a certain range of kernel virtual memory 199 * with new bootmem page tables, everywhere page tables are missing in 200 * the given range. 201 * 202 * NOTE: The pagetables are allocated contiguous on the physical space 203 * so we can cache the place of the first one and move around without 204 * checking the pgd every time. 205 */ 206 static void __init 207 page_table_range_init(unsigned long start, unsigned long end, pgd_t *pgd_base) 208 { 209 int pgd_idx, pmd_idx; 210 unsigned long vaddr; 211 pgd_t *pgd; 212 pmd_t *pmd; 213 pte_t *pte = NULL; 214 unsigned long count = page_table_range_init_count(start, end); 215 void *adr = NULL; 216 217 if (count) 218 adr = alloc_low_pages(count); 219 220 vaddr = start; 221 pgd_idx = pgd_index(vaddr); 222 pmd_idx = pmd_index(vaddr); 223 pgd = pgd_base + pgd_idx; 224 225 for ( ; (pgd_idx < PTRS_PER_PGD) && (vaddr != end); pgd++, pgd_idx++) { 226 pmd = one_md_table_init(pgd); 227 pmd = pmd + pmd_index(vaddr); 228 for (; (pmd_idx < PTRS_PER_PMD) && (vaddr != end); 229 pmd++, pmd_idx++) { 230 pte = page_table_kmap_check(one_page_table_init(pmd), 231 pmd, vaddr, pte, &adr); 232 233 vaddr += PMD_SIZE; 234 } 235 pmd_idx = 0; 236 } 237 } 238 239 static inline int is_kernel_text(unsigned long addr) 240 { 241 if (addr >= (unsigned long)_text && addr <= (unsigned long)__init_end) 242 return 1; 243 return 0; 244 } 245 246 /* 247 * This maps the physical memory to kernel virtual address space, a total 248 * of max_low_pfn pages, by creating page tables starting from address 249 * PAGE_OFFSET: 250 */ 251 unsigned long __init 252 kernel_physical_mapping_init(unsigned long start, 253 unsigned long end, 254 unsigned long page_size_mask) 255 { 256 int use_pse = page_size_mask == (1<<PG_LEVEL_2M); 257 unsigned long last_map_addr = end; 258 unsigned long start_pfn, end_pfn; 259 pgd_t *pgd_base = swapper_pg_dir; 260 int pgd_idx, pmd_idx, pte_ofs; 261 unsigned long pfn; 262 pgd_t *pgd; 263 pmd_t *pmd; 264 pte_t *pte; 265 unsigned pages_2m, pages_4k; 266 int mapping_iter; 267 268 start_pfn = start >> PAGE_SHIFT; 269 end_pfn = end >> PAGE_SHIFT; 270 271 /* 272 * First iteration will setup identity mapping using large/small pages 273 * based on use_pse, with other attributes same as set by 274 * the early code in head_32.S 275 * 276 * Second iteration will setup the appropriate attributes (NX, GLOBAL..) 277 * as desired for the kernel identity mapping. 278 * 279 * This two pass mechanism conforms to the TLB app note which says: 280 * 281 * "Software should not write to a paging-structure entry in a way 282 * that would change, for any linear address, both the page size 283 * and either the page frame or attributes." 284 */ 285 mapping_iter = 1; 286 287 if (!boot_cpu_has(X86_FEATURE_PSE)) 288 use_pse = 0; 289 290 repeat: 291 pages_2m = pages_4k = 0; 292 pfn = start_pfn; 293 pgd_idx = pgd_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET); 294 pgd = pgd_base + pgd_idx; 295 for (; pgd_idx < PTRS_PER_PGD; pgd++, pgd_idx++) { 296 pmd = one_md_table_init(pgd); 297 298 if (pfn >= end_pfn) 299 continue; 300 #ifdef CONFIG_X86_PAE 301 pmd_idx = pmd_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET); 302 pmd += pmd_idx; 303 #else 304 pmd_idx = 0; 305 #endif 306 for (; pmd_idx < PTRS_PER_PMD && pfn < end_pfn; 307 pmd++, pmd_idx++) { 308 unsigned int addr = pfn * PAGE_SIZE + PAGE_OFFSET; 309 310 /* 311 * Map with big pages if possible, otherwise 312 * create normal page tables: 313 */ 314 if (use_pse) { 315 unsigned int addr2; 316 pgprot_t prot = PAGE_KERNEL_LARGE; 317 /* 318 * first pass will use the same initial 319 * identity mapping attribute + _PAGE_PSE. 320 */ 321 pgprot_t init_prot = 322 __pgprot(PTE_IDENT_ATTR | 323 _PAGE_PSE); 324 325 pfn &= PMD_MASK >> PAGE_SHIFT; 326 addr2 = (pfn + PTRS_PER_PTE-1) * PAGE_SIZE + 327 PAGE_OFFSET + PAGE_SIZE-1; 328 329 if (is_kernel_text(addr) || 330 is_kernel_text(addr2)) 331 prot = PAGE_KERNEL_LARGE_EXEC; 332 333 pages_2m++; 334 if (mapping_iter == 1) 335 set_pmd(pmd, pfn_pmd(pfn, init_prot)); 336 else 337 set_pmd(pmd, pfn_pmd(pfn, prot)); 338 339 pfn += PTRS_PER_PTE; 340 continue; 341 } 342 pte = one_page_table_init(pmd); 343 344 pte_ofs = pte_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET); 345 pte += pte_ofs; 346 for (; pte_ofs < PTRS_PER_PTE && pfn < end_pfn; 347 pte++, pfn++, pte_ofs++, addr += PAGE_SIZE) { 348 pgprot_t prot = PAGE_KERNEL; 349 /* 350 * first pass will use the same initial 351 * identity mapping attribute. 352 */ 353 pgprot_t init_prot = __pgprot(PTE_IDENT_ATTR); 354 355 if (is_kernel_text(addr)) 356 prot = PAGE_KERNEL_EXEC; 357 358 pages_4k++; 359 if (mapping_iter == 1) { 360 set_pte(pte, pfn_pte(pfn, init_prot)); 361 last_map_addr = (pfn << PAGE_SHIFT) + PAGE_SIZE; 362 } else 363 set_pte(pte, pfn_pte(pfn, prot)); 364 } 365 } 366 } 367 if (mapping_iter == 1) { 368 /* 369 * update direct mapping page count only in the first 370 * iteration. 371 */ 372 update_page_count(PG_LEVEL_2M, pages_2m); 373 update_page_count(PG_LEVEL_4K, pages_4k); 374 375 /* 376 * local global flush tlb, which will flush the previous 377 * mappings present in both small and large page TLB's. 378 */ 379 __flush_tlb_all(); 380 381 /* 382 * Second iteration will set the actual desired PTE attributes. 383 */ 384 mapping_iter = 2; 385 goto repeat; 386 } 387 return last_map_addr; 388 } 389 390 pte_t *kmap_pte; 391 392 static inline pte_t *kmap_get_fixmap_pte(unsigned long vaddr) 393 { 394 pgd_t *pgd = pgd_offset_k(vaddr); 395 p4d_t *p4d = p4d_offset(pgd, vaddr); 396 pud_t *pud = pud_offset(p4d, vaddr); 397 pmd_t *pmd = pmd_offset(pud, vaddr); 398 return pte_offset_kernel(pmd, vaddr); 399 } 400 401 static void __init kmap_init(void) 402 { 403 unsigned long kmap_vstart; 404 405 /* 406 * Cache the first kmap pte: 407 */ 408 kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN); 409 kmap_pte = kmap_get_fixmap_pte(kmap_vstart); 410 } 411 412 #ifdef CONFIG_HIGHMEM 413 static void __init permanent_kmaps_init(pgd_t *pgd_base) 414 { 415 unsigned long vaddr; 416 pgd_t *pgd; 417 p4d_t *p4d; 418 pud_t *pud; 419 pmd_t *pmd; 420 pte_t *pte; 421 422 vaddr = PKMAP_BASE; 423 page_table_range_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, pgd_base); 424 425 pgd = swapper_pg_dir + pgd_index(vaddr); 426 p4d = p4d_offset(pgd, vaddr); 427 pud = pud_offset(p4d, vaddr); 428 pmd = pmd_offset(pud, vaddr); 429 pte = pte_offset_kernel(pmd, vaddr); 430 pkmap_page_table = pte; 431 } 432 433 void __init add_highpages_with_active_regions(int nid, 434 unsigned long start_pfn, unsigned long end_pfn) 435 { 436 phys_addr_t start, end; 437 u64 i; 438 439 for_each_free_mem_range(i, nid, MEMBLOCK_NONE, &start, &end, NULL) { 440 unsigned long pfn = clamp_t(unsigned long, PFN_UP(start), 441 start_pfn, end_pfn); 442 unsigned long e_pfn = clamp_t(unsigned long, PFN_DOWN(end), 443 start_pfn, end_pfn); 444 for ( ; pfn < e_pfn; pfn++) 445 if (pfn_valid(pfn)) 446 free_highmem_page(pfn_to_page(pfn)); 447 } 448 } 449 #else 450 static inline void permanent_kmaps_init(pgd_t *pgd_base) 451 { 452 } 453 #endif /* CONFIG_HIGHMEM */ 454 455 void __init sync_initial_page_table(void) 456 { 457 clone_pgd_range(initial_page_table + KERNEL_PGD_BOUNDARY, 458 swapper_pg_dir + KERNEL_PGD_BOUNDARY, 459 KERNEL_PGD_PTRS); 460 461 /* 462 * sync back low identity map too. It is used for example 463 * in the 32-bit EFI stub. 464 */ 465 clone_pgd_range(initial_page_table, 466 swapper_pg_dir + KERNEL_PGD_BOUNDARY, 467 min(KERNEL_PGD_PTRS, KERNEL_PGD_BOUNDARY)); 468 } 469 470 void __init native_pagetable_init(void) 471 { 472 unsigned long pfn, va; 473 pgd_t *pgd, *base = swapper_pg_dir; 474 p4d_t *p4d; 475 pud_t *pud; 476 pmd_t *pmd; 477 pte_t *pte; 478 479 /* 480 * Remove any mappings which extend past the end of physical 481 * memory from the boot time page table. 482 * In virtual address space, we should have at least two pages 483 * from VMALLOC_END to pkmap or fixmap according to VMALLOC_END 484 * definition. And max_low_pfn is set to VMALLOC_END physical 485 * address. If initial memory mapping is doing right job, we 486 * should have pte used near max_low_pfn or one pmd is not present. 487 */ 488 for (pfn = max_low_pfn; pfn < 1<<(32-PAGE_SHIFT); pfn++) { 489 va = PAGE_OFFSET + (pfn<<PAGE_SHIFT); 490 pgd = base + pgd_index(va); 491 if (!pgd_present(*pgd)) 492 break; 493 494 p4d = p4d_offset(pgd, va); 495 pud = pud_offset(p4d, va); 496 pmd = pmd_offset(pud, va); 497 if (!pmd_present(*pmd)) 498 break; 499 500 /* should not be large page here */ 501 if (pmd_large(*pmd)) { 502 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", 503 pfn, pmd, __pa(pmd)); 504 BUG_ON(1); 505 } 506 507 pte = pte_offset_kernel(pmd, va); 508 if (!pte_present(*pte)) 509 break; 510 511 printk(KERN_DEBUG "clearing pte for ram above max_low_pfn: pfn: %lx pmd: %p pmd phys: %lx pte: %p pte phys: %lx\n", 512 pfn, pmd, __pa(pmd), pte, __pa(pte)); 513 pte_clear(NULL, va, pte); 514 } 515 paravirt_alloc_pmd(&init_mm, __pa(base) >> PAGE_SHIFT); 516 paging_init(); 517 } 518 519 /* 520 * Build a proper pagetable for the kernel mappings. Up until this 521 * point, we've been running on some set of pagetables constructed by 522 * the boot process. 523 * 524 * If we're booting on native hardware, this will be a pagetable 525 * constructed in arch/x86/kernel/head_32.S. The root of the 526 * pagetable will be swapper_pg_dir. 527 * 528 * If we're booting paravirtualized under a hypervisor, then there are 529 * more options: we may already be running PAE, and the pagetable may 530 * or may not be based in swapper_pg_dir. In any case, 531 * paravirt_pagetable_init() will set up swapper_pg_dir 532 * appropriately for the rest of the initialization to work. 533 * 534 * In general, pagetable_init() assumes that the pagetable may already 535 * be partially populated, and so it avoids stomping on any existing 536 * mappings. 537 */ 538 void __init early_ioremap_page_table_range_init(void) 539 { 540 pgd_t *pgd_base = swapper_pg_dir; 541 unsigned long vaddr, end; 542 543 /* 544 * Fixed mappings, only the page table structure has to be 545 * created - mappings will be set by set_fixmap(): 546 */ 547 vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK; 548 end = (FIXADDR_TOP + PMD_SIZE - 1) & PMD_MASK; 549 page_table_range_init(vaddr, end, pgd_base); 550 early_ioremap_reset(); 551 } 552 553 static void __init pagetable_init(void) 554 { 555 pgd_t *pgd_base = swapper_pg_dir; 556 557 permanent_kmaps_init(pgd_base); 558 } 559 560 #define DEFAULT_PTE_MASK ~(_PAGE_NX | _PAGE_GLOBAL) 561 /* Bits supported by the hardware: */ 562 pteval_t __supported_pte_mask __read_mostly = DEFAULT_PTE_MASK; 563 /* Bits allowed in normal kernel mappings: */ 564 pteval_t __default_kernel_pte_mask __read_mostly = DEFAULT_PTE_MASK; 565 EXPORT_SYMBOL_GPL(__supported_pte_mask); 566 /* Used in PAGE_KERNEL_* macros which are reasonably used out-of-tree: */ 567 EXPORT_SYMBOL(__default_kernel_pte_mask); 568 569 /* user-defined highmem size */ 570 static unsigned int highmem_pages = -1; 571 572 /* 573 * highmem=size forces highmem to be exactly 'size' bytes. 574 * This works even on boxes that have no highmem otherwise. 575 * This also works to reduce highmem size on bigger boxes. 576 */ 577 static int __init parse_highmem(char *arg) 578 { 579 if (!arg) 580 return -EINVAL; 581 582 highmem_pages = memparse(arg, &arg) >> PAGE_SHIFT; 583 return 0; 584 } 585 early_param("highmem", parse_highmem); 586 587 #define MSG_HIGHMEM_TOO_BIG \ 588 "highmem size (%luMB) is bigger than pages available (%luMB)!\n" 589 590 #define MSG_LOWMEM_TOO_SMALL \ 591 "highmem size (%luMB) results in <64MB lowmem, ignoring it!\n" 592 /* 593 * All of RAM fits into lowmem - but if user wants highmem 594 * artificially via the highmem=x boot parameter then create 595 * it: 596 */ 597 static void __init lowmem_pfn_init(void) 598 { 599 /* max_low_pfn is 0, we already have early_res support */ 600 max_low_pfn = max_pfn; 601 602 if (highmem_pages == -1) 603 highmem_pages = 0; 604 #ifdef CONFIG_HIGHMEM 605 if (highmem_pages >= max_pfn) { 606 printk(KERN_ERR MSG_HIGHMEM_TOO_BIG, 607 pages_to_mb(highmem_pages), pages_to_mb(max_pfn)); 608 highmem_pages = 0; 609 } 610 if (highmem_pages) { 611 if (max_low_pfn - highmem_pages < 64*1024*1024/PAGE_SIZE) { 612 printk(KERN_ERR MSG_LOWMEM_TOO_SMALL, 613 pages_to_mb(highmem_pages)); 614 highmem_pages = 0; 615 } 616 max_low_pfn -= highmem_pages; 617 } 618 #else 619 if (highmem_pages) 620 printk(KERN_ERR "ignoring highmem size on non-highmem kernel!\n"); 621 #endif 622 } 623 624 #define MSG_HIGHMEM_TOO_SMALL \ 625 "only %luMB highmem pages available, ignoring highmem size of %luMB!\n" 626 627 #define MSG_HIGHMEM_TRIMMED \ 628 "Warning: only 4GB will be used. Use a HIGHMEM64G enabled kernel!\n" 629 /* 630 * We have more RAM than fits into lowmem - we try to put it into 631 * highmem, also taking the highmem=x boot parameter into account: 632 */ 633 static void __init highmem_pfn_init(void) 634 { 635 max_low_pfn = MAXMEM_PFN; 636 637 if (highmem_pages == -1) 638 highmem_pages = max_pfn - MAXMEM_PFN; 639 640 if (highmem_pages + MAXMEM_PFN < max_pfn) 641 max_pfn = MAXMEM_PFN + highmem_pages; 642 643 if (highmem_pages + MAXMEM_PFN > max_pfn) { 644 printk(KERN_WARNING MSG_HIGHMEM_TOO_SMALL, 645 pages_to_mb(max_pfn - MAXMEM_PFN), 646 pages_to_mb(highmem_pages)); 647 highmem_pages = 0; 648 } 649 #ifndef CONFIG_HIGHMEM 650 /* Maximum memory usable is what is directly addressable */ 651 printk(KERN_WARNING "Warning only %ldMB will be used.\n", MAXMEM>>20); 652 if (max_pfn > MAX_NONPAE_PFN) 653 printk(KERN_WARNING "Use a HIGHMEM64G enabled kernel.\n"); 654 else 655 printk(KERN_WARNING "Use a HIGHMEM enabled kernel.\n"); 656 max_pfn = MAXMEM_PFN; 657 #else /* !CONFIG_HIGHMEM */ 658 #ifndef CONFIG_HIGHMEM64G 659 if (max_pfn > MAX_NONPAE_PFN) { 660 max_pfn = MAX_NONPAE_PFN; 661 printk(KERN_WARNING MSG_HIGHMEM_TRIMMED); 662 } 663 #endif /* !CONFIG_HIGHMEM64G */ 664 #endif /* !CONFIG_HIGHMEM */ 665 } 666 667 /* 668 * Determine low and high memory ranges: 669 */ 670 void __init find_low_pfn_range(void) 671 { 672 /* it could update max_pfn */ 673 674 if (max_pfn <= MAXMEM_PFN) 675 lowmem_pfn_init(); 676 else 677 highmem_pfn_init(); 678 } 679 680 #ifndef CONFIG_NEED_MULTIPLE_NODES 681 void __init initmem_init(void) 682 { 683 #ifdef CONFIG_HIGHMEM 684 highstart_pfn = highend_pfn = max_pfn; 685 if (max_pfn > max_low_pfn) 686 highstart_pfn = max_low_pfn; 687 printk(KERN_NOTICE "%ldMB HIGHMEM available.\n", 688 pages_to_mb(highend_pfn - highstart_pfn)); 689 high_memory = (void *) __va(highstart_pfn * PAGE_SIZE - 1) + 1; 690 #else 691 high_memory = (void *) __va(max_low_pfn * PAGE_SIZE - 1) + 1; 692 #endif 693 694 memblock_set_node(0, PHYS_ADDR_MAX, &memblock.memory, 0); 695 sparse_memory_present_with_active_regions(0); 696 697 #ifdef CONFIG_FLATMEM 698 max_mapnr = IS_ENABLED(CONFIG_HIGHMEM) ? highend_pfn : max_low_pfn; 699 #endif 700 __vmalloc_start_set = true; 701 702 printk(KERN_NOTICE "%ldMB LOWMEM available.\n", 703 pages_to_mb(max_low_pfn)); 704 705 setup_bootmem_allocator(); 706 } 707 #endif /* !CONFIG_NEED_MULTIPLE_NODES */ 708 709 void __init setup_bootmem_allocator(void) 710 { 711 printk(KERN_INFO " mapped low ram: 0 - %08lx\n", 712 max_pfn_mapped<<PAGE_SHIFT); 713 printk(KERN_INFO " low ram: 0 - %08lx\n", max_low_pfn<<PAGE_SHIFT); 714 } 715 716 /* 717 * paging_init() sets up the page tables - note that the first 8MB are 718 * already mapped by head.S. 719 * 720 * This routines also unmaps the page at virtual kernel address 0, so 721 * that we can trap those pesky NULL-reference errors in the kernel. 722 */ 723 void __init paging_init(void) 724 { 725 pagetable_init(); 726 727 __flush_tlb_all(); 728 729 kmap_init(); 730 731 /* 732 * NOTE: at this point the bootmem allocator is fully available. 733 */ 734 olpc_dt_build_devicetree(); 735 sparse_memory_present_with_active_regions(MAX_NUMNODES); 736 sparse_init(); 737 zone_sizes_init(); 738 } 739 740 /* 741 * Test if the WP bit works in supervisor mode. It isn't supported on 386's 742 * and also on some strange 486's. All 586+'s are OK. This used to involve 743 * black magic jumps to work around some nasty CPU bugs, but fortunately the 744 * switch to using exceptions got rid of all that. 745 */ 746 static void __init test_wp_bit(void) 747 { 748 char z = 0; 749 750 printk(KERN_INFO "Checking if this processor honours the WP bit even in supervisor mode..."); 751 752 __set_fixmap(FIX_WP_TEST, __pa_symbol(empty_zero_page), PAGE_KERNEL_RO); 753 754 if (probe_kernel_write((char *)fix_to_virt(FIX_WP_TEST), &z, 1)) { 755 clear_fixmap(FIX_WP_TEST); 756 printk(KERN_CONT "Ok.\n"); 757 return; 758 } 759 760 printk(KERN_CONT "No.\n"); 761 panic("Linux doesn't support CPUs with broken WP."); 762 } 763 764 void __init mem_init(void) 765 { 766 pci_iommu_alloc(); 767 768 #ifdef CONFIG_FLATMEM 769 BUG_ON(!mem_map); 770 #endif 771 /* 772 * With CONFIG_DEBUG_PAGEALLOC initialization of highmem pages has to 773 * be done before memblock_free_all(). Memblock use free low memory for 774 * temporary data (see find_range_array()) and for this purpose can use 775 * pages that was already passed to the buddy allocator, hence marked as 776 * not accessible in the page tables when compiled with 777 * CONFIG_DEBUG_PAGEALLOC. Otherwise order of initialization is not 778 * important here. 779 */ 780 set_highmem_pages_init(); 781 782 /* this will put all low memory onto the freelists */ 783 memblock_free_all(); 784 785 after_bootmem = 1; 786 x86_init.hyper.init_after_bootmem(); 787 788 mem_init_print_info(NULL); 789 printk(KERN_INFO "virtual kernel memory layout:\n" 790 " fixmap : 0x%08lx - 0x%08lx (%4ld kB)\n" 791 " cpu_entry : 0x%08lx - 0x%08lx (%4ld kB)\n" 792 #ifdef CONFIG_HIGHMEM 793 " pkmap : 0x%08lx - 0x%08lx (%4ld kB)\n" 794 #endif 795 " vmalloc : 0x%08lx - 0x%08lx (%4ld MB)\n" 796 " lowmem : 0x%08lx - 0x%08lx (%4ld MB)\n" 797 " .init : 0x%08lx - 0x%08lx (%4ld kB)\n" 798 " .data : 0x%08lx - 0x%08lx (%4ld kB)\n" 799 " .text : 0x%08lx - 0x%08lx (%4ld kB)\n", 800 FIXADDR_START, FIXADDR_TOP, 801 (FIXADDR_TOP - FIXADDR_START) >> 10, 802 803 CPU_ENTRY_AREA_BASE, 804 CPU_ENTRY_AREA_BASE + CPU_ENTRY_AREA_MAP_SIZE, 805 CPU_ENTRY_AREA_MAP_SIZE >> 10, 806 807 #ifdef CONFIG_HIGHMEM 808 PKMAP_BASE, PKMAP_BASE+LAST_PKMAP*PAGE_SIZE, 809 (LAST_PKMAP*PAGE_SIZE) >> 10, 810 #endif 811 812 VMALLOC_START, VMALLOC_END, 813 (VMALLOC_END - VMALLOC_START) >> 20, 814 815 (unsigned long)__va(0), (unsigned long)high_memory, 816 ((unsigned long)high_memory - (unsigned long)__va(0)) >> 20, 817 818 (unsigned long)&__init_begin, (unsigned long)&__init_end, 819 ((unsigned long)&__init_end - 820 (unsigned long)&__init_begin) >> 10, 821 822 (unsigned long)&_etext, (unsigned long)&_edata, 823 ((unsigned long)&_edata - (unsigned long)&_etext) >> 10, 824 825 (unsigned long)&_text, (unsigned long)&_etext, 826 ((unsigned long)&_etext - (unsigned long)&_text) >> 10); 827 828 /* 829 * Check boundaries twice: Some fundamental inconsistencies can 830 * be detected at build time already. 831 */ 832 #define __FIXADDR_TOP (-PAGE_SIZE) 833 #ifdef CONFIG_HIGHMEM 834 BUILD_BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE > FIXADDR_START); 835 BUILD_BUG_ON(VMALLOC_END > PKMAP_BASE); 836 #endif 837 #define high_memory (-128UL << 20) 838 BUILD_BUG_ON(VMALLOC_START >= VMALLOC_END); 839 #undef high_memory 840 #undef __FIXADDR_TOP 841 842 #ifdef CONFIG_HIGHMEM 843 BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE > FIXADDR_START); 844 BUG_ON(VMALLOC_END > PKMAP_BASE); 845 #endif 846 BUG_ON(VMALLOC_START >= VMALLOC_END); 847 BUG_ON((unsigned long)high_memory > VMALLOC_START); 848 849 test_wp_bit(); 850 } 851 852 #ifdef CONFIG_MEMORY_HOTPLUG 853 int arch_add_memory(int nid, u64 start, u64 size, struct vmem_altmap *altmap, 854 bool want_memblock) 855 { 856 unsigned long start_pfn = start >> PAGE_SHIFT; 857 unsigned long nr_pages = size >> PAGE_SHIFT; 858 859 return __add_pages(nid, start_pfn, nr_pages, altmap, want_memblock); 860 } 861 862 #ifdef CONFIG_MEMORY_HOTREMOVE 863 int arch_remove_memory(int nid, u64 start, u64 size, struct vmem_altmap *altmap) 864 { 865 unsigned long start_pfn = start >> PAGE_SHIFT; 866 unsigned long nr_pages = size >> PAGE_SHIFT; 867 struct zone *zone; 868 869 zone = page_zone(pfn_to_page(start_pfn)); 870 return __remove_pages(zone, start_pfn, nr_pages, altmap); 871 } 872 #endif 873 #endif 874 875 int kernel_set_to_readonly __read_mostly; 876 877 void set_kernel_text_rw(void) 878 { 879 unsigned long start = PFN_ALIGN(_text); 880 unsigned long size = PFN_ALIGN(_etext) - start; 881 882 if (!kernel_set_to_readonly) 883 return; 884 885 pr_debug("Set kernel text: %lx - %lx for read write\n", 886 start, start+size); 887 888 set_pages_rw(virt_to_page(start), size >> PAGE_SHIFT); 889 } 890 891 void set_kernel_text_ro(void) 892 { 893 unsigned long start = PFN_ALIGN(_text); 894 unsigned long size = PFN_ALIGN(_etext) - start; 895 896 if (!kernel_set_to_readonly) 897 return; 898 899 pr_debug("Set kernel text: %lx - %lx for read only\n", 900 start, start+size); 901 902 set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT); 903 } 904 905 static void mark_nxdata_nx(void) 906 { 907 /* 908 * When this called, init has already been executed and released, 909 * so everything past _etext should be NX. 910 */ 911 unsigned long start = PFN_ALIGN(_etext); 912 /* 913 * This comes from is_kernel_text upper limit. Also HPAGE where used: 914 */ 915 unsigned long size = (((unsigned long)__init_end + HPAGE_SIZE) & HPAGE_MASK) - start; 916 917 if (__supported_pte_mask & _PAGE_NX) 918 printk(KERN_INFO "NX-protecting the kernel data: %luk\n", size >> 10); 919 set_pages_nx(virt_to_page(start), size >> PAGE_SHIFT); 920 } 921 922 void mark_rodata_ro(void) 923 { 924 unsigned long start = PFN_ALIGN(_text); 925 unsigned long size = (unsigned long)__end_rodata - start; 926 927 set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT); 928 pr_info("Write protecting kernel text and read-only data: %luk\n", 929 size >> 10); 930 931 kernel_set_to_readonly = 1; 932 933 #ifdef CONFIG_CPA_DEBUG 934 pr_info("Testing CPA: Reverting %lx-%lx\n", start, start + size); 935 set_pages_rw(virt_to_page(start), size >> PAGE_SHIFT); 936 937 pr_info("Testing CPA: write protecting again\n"); 938 set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT); 939 #endif 940 mark_nxdata_nx(); 941 if (__supported_pte_mask & _PAGE_NX) 942 debug_checkwx(); 943 } 944