1 /* 2 * linux/init/main.c 3 * 4 * Copyright (C) 1991, 1992 Linus Torvalds 5 * 6 * GK 2/5/95 - Changed to support mounting root fs via NFS 7 * Added initrd & change_root: Werner Almesberger & Hans Lermen, Feb '96 8 * Moan early if gcc is old, avoiding bogus kernels - Paul Gortmaker, May '96 9 * Simplified starting of init: Michael A. Griffith <grif@acm.org> 10 */ 11 12 #include <linux/types.h> 13 #include <linux/module.h> 14 #include <linux/proc_fs.h> 15 #include <linux/kernel.h> 16 #include <linux/syscalls.h> 17 #include <linux/stackprotector.h> 18 #include <linux/string.h> 19 #include <linux/ctype.h> 20 #include <linux/delay.h> 21 #include <linux/ioport.h> 22 #include <linux/init.h> 23 #include <linux/initrd.h> 24 #include <linux/bootmem.h> 25 #include <linux/acpi.h> 26 #include <linux/tty.h> 27 #include <linux/percpu.h> 28 #include <linux/kmod.h> 29 #include <linux/vmalloc.h> 30 #include <linux/kernel_stat.h> 31 #include <linux/start_kernel.h> 32 #include <linux/security.h> 33 #include <linux/smp.h> 34 #include <linux/profile.h> 35 #include <linux/rcupdate.h> 36 #include <linux/moduleparam.h> 37 #include <linux/kallsyms.h> 38 #include <linux/writeback.h> 39 #include <linux/cpu.h> 40 #include <linux/cpuset.h> 41 #include <linux/cgroup.h> 42 #include <linux/efi.h> 43 #include <linux/tick.h> 44 #include <linux/interrupt.h> 45 #include <linux/taskstats_kern.h> 46 #include <linux/delayacct.h> 47 #include <linux/unistd.h> 48 #include <linux/rmap.h> 49 #include <linux/mempolicy.h> 50 #include <linux/key.h> 51 #include <linux/buffer_head.h> 52 #include <linux/page_cgroup.h> 53 #include <linux/debug_locks.h> 54 #include <linux/debugobjects.h> 55 #include <linux/lockdep.h> 56 #include <linux/kmemleak.h> 57 #include <linux/pid_namespace.h> 58 #include <linux/device.h> 59 #include <linux/kthread.h> 60 #include <linux/sched.h> 61 #include <linux/signal.h> 62 #include <linux/idr.h> 63 #include <linux/kgdb.h> 64 #include <linux/ftrace.h> 65 #include <linux/async.h> 66 #include <linux/kmemcheck.h> 67 #include <linux/sfi.h> 68 #include <linux/shmem_fs.h> 69 #include <linux/slab.h> 70 71 #include <asm/io.h> 72 #include <asm/bugs.h> 73 #include <asm/setup.h> 74 #include <asm/sections.h> 75 #include <asm/cacheflush.h> 76 77 #ifdef CONFIG_X86_LOCAL_APIC 78 #include <asm/smp.h> 79 #endif 80 81 static int kernel_init(void *); 82 83 extern void init_IRQ(void); 84 extern void fork_init(unsigned long); 85 extern void mca_init(void); 86 extern void sbus_init(void); 87 extern void prio_tree_init(void); 88 extern void radix_tree_init(void); 89 extern void free_initmem(void); 90 #ifndef CONFIG_DEBUG_RODATA 91 static inline void mark_rodata_ro(void) { } 92 #endif 93 94 #ifdef CONFIG_TC 95 extern void tc_init(void); 96 #endif 97 98 enum system_states system_state __read_mostly; 99 EXPORT_SYMBOL(system_state); 100 101 /* 102 * Boot command-line arguments 103 */ 104 #define MAX_INIT_ARGS CONFIG_INIT_ENV_ARG_LIMIT 105 #define MAX_INIT_ENVS CONFIG_INIT_ENV_ARG_LIMIT 106 107 extern void time_init(void); 108 /* Default late time init is NULL. archs can override this later. */ 109 void (*__initdata late_time_init)(void); 110 extern void softirq_init(void); 111 112 /* Untouched command line saved by arch-specific code. */ 113 char __initdata boot_command_line[COMMAND_LINE_SIZE]; 114 /* Untouched saved command line (eg. for /proc) */ 115 char *saved_command_line; 116 /* Command line for parameter parsing */ 117 static char *static_command_line; 118 119 static char *execute_command; 120 static char *ramdisk_execute_command; 121 122 #ifdef CONFIG_SMP 123 /* Setup configured maximum number of CPUs to activate */ 124 unsigned int setup_max_cpus = NR_CPUS; 125 EXPORT_SYMBOL(setup_max_cpus); 126 127 128 /* 129 * Setup routine for controlling SMP activation 130 * 131 * Command-line option of "nosmp" or "maxcpus=0" will disable SMP 132 * activation entirely (the MPS table probe still happens, though). 133 * 134 * Command-line option of "maxcpus=<NUM>", where <NUM> is an integer 135 * greater than 0, limits the maximum number of CPUs activated in 136 * SMP mode to <NUM>. 137 */ 138 139 void __weak arch_disable_smp_support(void) { } 140 141 static int __init nosmp(char *str) 142 { 143 setup_max_cpus = 0; 144 arch_disable_smp_support(); 145 146 return 0; 147 } 148 149 early_param("nosmp", nosmp); 150 151 /* this is hard limit */ 152 static int __init nrcpus(char *str) 153 { 154 int nr_cpus; 155 156 get_option(&str, &nr_cpus); 157 if (nr_cpus > 0 && nr_cpus < nr_cpu_ids) 158 nr_cpu_ids = nr_cpus; 159 160 return 0; 161 } 162 163 early_param("nr_cpus", nrcpus); 164 165 static int __init maxcpus(char *str) 166 { 167 get_option(&str, &setup_max_cpus); 168 if (setup_max_cpus == 0) 169 arch_disable_smp_support(); 170 171 return 0; 172 } 173 174 early_param("maxcpus", maxcpus); 175 #else 176 static const unsigned int setup_max_cpus = NR_CPUS; 177 #endif 178 179 /* 180 * If set, this is an indication to the drivers that reset the underlying 181 * device before going ahead with the initialization otherwise driver might 182 * rely on the BIOS and skip the reset operation. 183 * 184 * This is useful if kernel is booting in an unreliable environment. 185 * For ex. kdump situaiton where previous kernel has crashed, BIOS has been 186 * skipped and devices will be in unknown state. 187 */ 188 unsigned int reset_devices; 189 EXPORT_SYMBOL(reset_devices); 190 191 static int __init set_reset_devices(char *str) 192 { 193 reset_devices = 1; 194 return 1; 195 } 196 197 __setup("reset_devices", set_reset_devices); 198 199 static const char * argv_init[MAX_INIT_ARGS+2] = { "init", NULL, }; 200 const char * envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, }; 201 static const char *panic_later, *panic_param; 202 203 extern const struct obs_kernel_param __setup_start[], __setup_end[]; 204 205 static int __init obsolete_checksetup(char *line) 206 { 207 const struct obs_kernel_param *p; 208 int had_early_param = 0; 209 210 p = __setup_start; 211 do { 212 int n = strlen(p->str); 213 if (!strncmp(line, p->str, n)) { 214 if (p->early) { 215 /* Already done in parse_early_param? 216 * (Needs exact match on param part). 217 * Keep iterating, as we can have early 218 * params and __setups of same names 8( */ 219 if (line[n] == '\0' || line[n] == '=') 220 had_early_param = 1; 221 } else if (!p->setup_func) { 222 printk(KERN_WARNING "Parameter %s is obsolete," 223 " ignored\n", p->str); 224 return 1; 225 } else if (p->setup_func(line + n)) 226 return 1; 227 } 228 p++; 229 } while (p < __setup_end); 230 231 return had_early_param; 232 } 233 234 /* 235 * This should be approx 2 Bo*oMips to start (note initial shift), and will 236 * still work even if initially too large, it will just take slightly longer 237 */ 238 unsigned long loops_per_jiffy = (1<<12); 239 240 EXPORT_SYMBOL(loops_per_jiffy); 241 242 static int __init debug_kernel(char *str) 243 { 244 console_loglevel = 10; 245 return 0; 246 } 247 248 static int __init quiet_kernel(char *str) 249 { 250 console_loglevel = 4; 251 return 0; 252 } 253 254 early_param("debug", debug_kernel); 255 early_param("quiet", quiet_kernel); 256 257 static int __init loglevel(char *str) 258 { 259 get_option(&str, &console_loglevel); 260 return 0; 261 } 262 263 early_param("loglevel", loglevel); 264 265 /* 266 * Unknown boot options get handed to init, unless they look like 267 * unused parameters (modprobe will find them in /proc/cmdline). 268 */ 269 static int __init unknown_bootoption(char *param, char *val) 270 { 271 /* Change NUL term back to "=", to make "param" the whole string. */ 272 if (val) { 273 /* param=val or param="val"? */ 274 if (val == param+strlen(param)+1) 275 val[-1] = '='; 276 else if (val == param+strlen(param)+2) { 277 val[-2] = '='; 278 memmove(val-1, val, strlen(val)+1); 279 val--; 280 } else 281 BUG(); 282 } 283 284 /* Handle obsolete-style parameters */ 285 if (obsolete_checksetup(param)) 286 return 0; 287 288 /* Unused module parameter. */ 289 if (strchr(param, '.') && (!val || strchr(param, '.') < val)) 290 return 0; 291 292 if (panic_later) 293 return 0; 294 295 if (val) { 296 /* Environment option */ 297 unsigned int i; 298 for (i = 0; envp_init[i]; i++) { 299 if (i == MAX_INIT_ENVS) { 300 panic_later = "Too many boot env vars at `%s'"; 301 panic_param = param; 302 } 303 if (!strncmp(param, envp_init[i], val - param)) 304 break; 305 } 306 envp_init[i] = param; 307 } else { 308 /* Command line option */ 309 unsigned int i; 310 for (i = 0; argv_init[i]; i++) { 311 if (i == MAX_INIT_ARGS) { 312 panic_later = "Too many boot init vars at `%s'"; 313 panic_param = param; 314 } 315 } 316 argv_init[i] = param; 317 } 318 return 0; 319 } 320 321 #ifdef CONFIG_DEBUG_PAGEALLOC 322 int __read_mostly debug_pagealloc_enabled = 0; 323 #endif 324 325 static int __init init_setup(char *str) 326 { 327 unsigned int i; 328 329 execute_command = str; 330 /* 331 * In case LILO is going to boot us with default command line, 332 * it prepends "auto" before the whole cmdline which makes 333 * the shell think it should execute a script with such name. 334 * So we ignore all arguments entered _before_ init=... [MJ] 335 */ 336 for (i = 1; i < MAX_INIT_ARGS; i++) 337 argv_init[i] = NULL; 338 return 1; 339 } 340 __setup("init=", init_setup); 341 342 static int __init rdinit_setup(char *str) 343 { 344 unsigned int i; 345 346 ramdisk_execute_command = str; 347 /* See "auto" comment in init_setup */ 348 for (i = 1; i < MAX_INIT_ARGS; i++) 349 argv_init[i] = NULL; 350 return 1; 351 } 352 __setup("rdinit=", rdinit_setup); 353 354 #ifndef CONFIG_SMP 355 356 #ifdef CONFIG_X86_LOCAL_APIC 357 static void __init smp_init(void) 358 { 359 APIC_init_uniprocessor(); 360 } 361 #else 362 #define smp_init() do { } while (0) 363 #endif 364 365 static inline void setup_nr_cpu_ids(void) { } 366 static inline void smp_prepare_cpus(unsigned int maxcpus) { } 367 368 #else 369 370 /* Setup number of possible processor ids */ 371 int nr_cpu_ids __read_mostly = NR_CPUS; 372 EXPORT_SYMBOL(nr_cpu_ids); 373 374 /* An arch may set nr_cpu_ids earlier if needed, so this would be redundant */ 375 static void __init setup_nr_cpu_ids(void) 376 { 377 nr_cpu_ids = find_last_bit(cpumask_bits(cpu_possible_mask),NR_CPUS) + 1; 378 } 379 380 /* Called by boot processor to activate the rest. */ 381 static void __init smp_init(void) 382 { 383 unsigned int cpu; 384 385 /* FIXME: This should be done in userspace --RR */ 386 for_each_present_cpu(cpu) { 387 if (num_online_cpus() >= setup_max_cpus) 388 break; 389 if (!cpu_online(cpu)) 390 cpu_up(cpu); 391 } 392 393 /* Any cleanup work */ 394 printk(KERN_INFO "Brought up %ld CPUs\n", (long)num_online_cpus()); 395 smp_cpus_done(setup_max_cpus); 396 } 397 398 #endif 399 400 /* 401 * We need to store the untouched command line for future reference. 402 * We also need to store the touched command line since the parameter 403 * parsing is performed in place, and we should allow a component to 404 * store reference of name/value for future reference. 405 */ 406 static void __init setup_command_line(char *command_line) 407 { 408 saved_command_line = alloc_bootmem(strlen (boot_command_line)+1); 409 static_command_line = alloc_bootmem(strlen (command_line)+1); 410 strcpy (saved_command_line, boot_command_line); 411 strcpy (static_command_line, command_line); 412 } 413 414 /* 415 * We need to finalize in a non-__init function or else race conditions 416 * between the root thread and the init thread may cause start_kernel to 417 * be reaped by free_initmem before the root thread has proceeded to 418 * cpu_idle. 419 * 420 * gcc-3.4 accidentally inlines this function, so use noinline. 421 */ 422 423 static __initdata DECLARE_COMPLETION(kthreadd_done); 424 425 static noinline void __init_refok rest_init(void) 426 { 427 int pid; 428 429 rcu_scheduler_starting(); 430 /* 431 * We need to spawn init first so that it obtains pid 1, however 432 * the init task will end up wanting to create kthreads, which, if 433 * we schedule it before we create kthreadd, will OOPS. 434 */ 435 kernel_thread(kernel_init, NULL, CLONE_FS | CLONE_SIGHAND); 436 numa_default_policy(); 437 pid = kernel_thread(kthreadd, NULL, CLONE_FS | CLONE_FILES); 438 rcu_read_lock(); 439 kthreadd_task = find_task_by_pid_ns(pid, &init_pid_ns); 440 rcu_read_unlock(); 441 complete(&kthreadd_done); 442 443 /* 444 * The boot idle thread must execute schedule() 445 * at least once to get things moving: 446 */ 447 init_idle_bootup_task(current); 448 preempt_enable_no_resched(); 449 schedule(); 450 preempt_disable(); 451 452 /* Call into cpu_idle with preempt disabled */ 453 cpu_idle(); 454 } 455 456 /* Check for early params. */ 457 static int __init do_early_param(char *param, char *val) 458 { 459 const struct obs_kernel_param *p; 460 461 for (p = __setup_start; p < __setup_end; p++) { 462 if ((p->early && strcmp(param, p->str) == 0) || 463 (strcmp(param, "console") == 0 && 464 strcmp(p->str, "earlycon") == 0) 465 ) { 466 if (p->setup_func(val) != 0) 467 printk(KERN_WARNING 468 "Malformed early option '%s'\n", param); 469 } 470 } 471 /* We accept everything at this stage. */ 472 return 0; 473 } 474 475 void __init parse_early_options(char *cmdline) 476 { 477 parse_args("early options", cmdline, NULL, 0, do_early_param); 478 } 479 480 /* Arch code calls this early on, or if not, just before other parsing. */ 481 void __init parse_early_param(void) 482 { 483 static __initdata int done = 0; 484 static __initdata char tmp_cmdline[COMMAND_LINE_SIZE]; 485 486 if (done) 487 return; 488 489 /* All fall through to do_early_param. */ 490 strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE); 491 parse_early_options(tmp_cmdline); 492 done = 1; 493 } 494 495 /* 496 * Activate the first processor. 497 */ 498 499 static void __init boot_cpu_init(void) 500 { 501 int cpu = smp_processor_id(); 502 /* Mark the boot cpu "present", "online" etc for SMP and UP case */ 503 set_cpu_online(cpu, true); 504 set_cpu_active(cpu, true); 505 set_cpu_present(cpu, true); 506 set_cpu_possible(cpu, true); 507 } 508 509 void __init __weak smp_setup_processor_id(void) 510 { 511 } 512 513 void __init __weak thread_info_cache_init(void) 514 { 515 } 516 517 /* 518 * Set up kernel memory allocators 519 */ 520 static void __init mm_init(void) 521 { 522 /* 523 * page_cgroup requires countinous pages as memmap 524 * and it's bigger than MAX_ORDER unless SPARSEMEM. 525 */ 526 page_cgroup_init_flatmem(); 527 mem_init(); 528 kmem_cache_init(); 529 percpu_init_late(); 530 pgtable_cache_init(); 531 vmalloc_init(); 532 } 533 534 asmlinkage void __init start_kernel(void) 535 { 536 char * command_line; 537 extern const struct kernel_param __start___param[], __stop___param[]; 538 539 smp_setup_processor_id(); 540 541 /* 542 * Need to run as early as possible, to initialize the 543 * lockdep hash: 544 */ 545 lockdep_init(); 546 debug_objects_early_init(); 547 548 /* 549 * Set up the the initial canary ASAP: 550 */ 551 boot_init_stack_canary(); 552 553 cgroup_init_early(); 554 555 local_irq_disable(); 556 early_boot_irqs_off(); 557 558 /* 559 * Interrupts are still disabled. Do necessary setups, then 560 * enable them 561 */ 562 tick_init(); 563 boot_cpu_init(); 564 page_address_init(); 565 printk(KERN_NOTICE "%s", linux_banner); 566 setup_arch(&command_line); 567 mm_init_owner(&init_mm, &init_task); 568 setup_command_line(command_line); 569 setup_nr_cpu_ids(); 570 setup_per_cpu_areas(); 571 smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */ 572 573 build_all_zonelists(NULL); 574 page_alloc_init(); 575 576 printk(KERN_NOTICE "Kernel command line: %s\n", boot_command_line); 577 parse_early_param(); 578 parse_args("Booting kernel", static_command_line, __start___param, 579 __stop___param - __start___param, 580 &unknown_bootoption); 581 /* 582 * These use large bootmem allocations and must precede 583 * kmem_cache_init() 584 */ 585 pidhash_init(); 586 vfs_caches_init_early(); 587 sort_main_extable(); 588 trap_init(); 589 mm_init(); 590 /* 591 * Set up the scheduler prior starting any interrupts (such as the 592 * timer interrupt). Full topology setup happens at smp_init() 593 * time - but meanwhile we still have a functioning scheduler. 594 */ 595 sched_init(); 596 /* 597 * Disable preemption - early bootup scheduling is extremely 598 * fragile until we cpu_idle() for the first time. 599 */ 600 preempt_disable(); 601 if (!irqs_disabled()) { 602 printk(KERN_WARNING "start_kernel(): bug: interrupts were " 603 "enabled *very* early, fixing it\n"); 604 local_irq_disable(); 605 } 606 rcu_init(); 607 radix_tree_init(); 608 /* init some links before init_ISA_irqs() */ 609 early_irq_init(); 610 init_IRQ(); 611 prio_tree_init(); 612 init_timers(); 613 hrtimers_init(); 614 softirq_init(); 615 timekeeping_init(); 616 time_init(); 617 profile_init(); 618 if (!irqs_disabled()) 619 printk(KERN_CRIT "start_kernel(): bug: interrupts were " 620 "enabled early\n"); 621 early_boot_irqs_on(); 622 local_irq_enable(); 623 624 /* Interrupts are enabled now so all GFP allocations are safe. */ 625 gfp_allowed_mask = __GFP_BITS_MASK; 626 627 kmem_cache_init_late(); 628 629 /* 630 * HACK ALERT! This is early. We're enabling the console before 631 * we've done PCI setups etc, and console_init() must be aware of 632 * this. But we do want output early, in case something goes wrong. 633 */ 634 console_init(); 635 if (panic_later) 636 panic(panic_later, panic_param); 637 638 lockdep_info(); 639 640 /* 641 * Need to run this when irqs are enabled, because it wants 642 * to self-test [hard/soft]-irqs on/off lock inversion bugs 643 * too: 644 */ 645 locking_selftest(); 646 647 #ifdef CONFIG_BLK_DEV_INITRD 648 if (initrd_start && !initrd_below_start_ok && 649 page_to_pfn(virt_to_page((void *)initrd_start)) < min_low_pfn) { 650 printk(KERN_CRIT "initrd overwritten (0x%08lx < 0x%08lx) - " 651 "disabling it.\n", 652 page_to_pfn(virt_to_page((void *)initrd_start)), 653 min_low_pfn); 654 initrd_start = 0; 655 } 656 #endif 657 page_cgroup_init(); 658 enable_debug_pagealloc(); 659 kmemleak_init(); 660 debug_objects_mem_init(); 661 idr_init_cache(); 662 setup_per_cpu_pageset(); 663 numa_policy_init(); 664 if (late_time_init) 665 late_time_init(); 666 sched_clock_init(); 667 calibrate_delay(); 668 pidmap_init(); 669 anon_vma_init(); 670 #ifdef CONFIG_X86 671 if (efi_enabled) 672 efi_enter_virtual_mode(); 673 #endif 674 thread_info_cache_init(); 675 cred_init(); 676 fork_init(totalram_pages); 677 proc_caches_init(); 678 buffer_init(); 679 key_init(); 680 security_init(); 681 dbg_late_init(); 682 vfs_caches_init(totalram_pages); 683 signals_init(); 684 /* rootfs populating might need page-writeback */ 685 page_writeback_init(); 686 #ifdef CONFIG_PROC_FS 687 proc_root_init(); 688 #endif 689 cgroup_init(); 690 cpuset_init(); 691 taskstats_init_early(); 692 delayacct_init(); 693 694 check_bugs(); 695 696 acpi_early_init(); /* before LAPIC and SMP init */ 697 sfi_init_late(); 698 699 ftrace_init(); 700 701 /* Do the rest non-__init'ed, we're now alive */ 702 rest_init(); 703 } 704 705 /* Call all constructor functions linked into the kernel. */ 706 static void __init do_ctors(void) 707 { 708 #ifdef CONFIG_CONSTRUCTORS 709 ctor_fn_t *fn = (ctor_fn_t *) __ctors_start; 710 711 for (; fn < (ctor_fn_t *) __ctors_end; fn++) 712 (*fn)(); 713 #endif 714 } 715 716 int initcall_debug; 717 core_param(initcall_debug, initcall_debug, bool, 0644); 718 719 static char msgbuf[64]; 720 721 static int __init_or_module do_one_initcall_debug(initcall_t fn) 722 { 723 ktime_t calltime, delta, rettime; 724 unsigned long long duration; 725 int ret; 726 727 printk(KERN_DEBUG "calling %pF @ %i\n", fn, task_pid_nr(current)); 728 calltime = ktime_get(); 729 ret = fn(); 730 rettime = ktime_get(); 731 delta = ktime_sub(rettime, calltime); 732 duration = (unsigned long long) ktime_to_ns(delta) >> 10; 733 printk(KERN_DEBUG "initcall %pF returned %d after %lld usecs\n", fn, 734 ret, duration); 735 736 return ret; 737 } 738 739 int __init_or_module do_one_initcall(initcall_t fn) 740 { 741 int count = preempt_count(); 742 int ret; 743 744 if (initcall_debug) 745 ret = do_one_initcall_debug(fn); 746 else 747 ret = fn(); 748 749 msgbuf[0] = 0; 750 751 if (ret && ret != -ENODEV && initcall_debug) 752 sprintf(msgbuf, "error code %d ", ret); 753 754 if (preempt_count() != count) { 755 strlcat(msgbuf, "preemption imbalance ", sizeof(msgbuf)); 756 preempt_count() = count; 757 } 758 if (irqs_disabled()) { 759 strlcat(msgbuf, "disabled interrupts ", sizeof(msgbuf)); 760 local_irq_enable(); 761 } 762 if (msgbuf[0]) { 763 printk("initcall %pF returned with %s\n", fn, msgbuf); 764 } 765 766 return ret; 767 } 768 769 770 extern initcall_t __initcall_start[], __initcall_end[], __early_initcall_end[]; 771 772 static void __init do_initcalls(void) 773 { 774 initcall_t *fn; 775 776 for (fn = __early_initcall_end; fn < __initcall_end; fn++) 777 do_one_initcall(*fn); 778 779 /* Make sure there is no pending stuff from the initcall sequence */ 780 flush_scheduled_work(); 781 } 782 783 /* 784 * Ok, the machine is now initialized. None of the devices 785 * have been touched yet, but the CPU subsystem is up and 786 * running, and memory and process management works. 787 * 788 * Now we can finally start doing some real work.. 789 */ 790 static void __init do_basic_setup(void) 791 { 792 cpuset_init_smp(); 793 usermodehelper_init(); 794 init_tmpfs(); 795 driver_init(); 796 init_irq_proc(); 797 do_ctors(); 798 do_initcalls(); 799 } 800 801 static void __init do_pre_smp_initcalls(void) 802 { 803 initcall_t *fn; 804 805 for (fn = __initcall_start; fn < __early_initcall_end; fn++) 806 do_one_initcall(*fn); 807 } 808 809 static void run_init_process(const char *init_filename) 810 { 811 argv_init[0] = init_filename; 812 kernel_execve(init_filename, argv_init, envp_init); 813 } 814 815 /* This is a non __init function. Force it to be noinline otherwise gcc 816 * makes it inline to init() and it becomes part of init.text section 817 */ 818 static noinline int init_post(void) 819 { 820 /* need to finish all async __init code before freeing the memory */ 821 async_synchronize_full(); 822 free_initmem(); 823 mark_rodata_ro(); 824 system_state = SYSTEM_RUNNING; 825 numa_default_policy(); 826 827 828 current->signal->flags |= SIGNAL_UNKILLABLE; 829 830 if (ramdisk_execute_command) { 831 run_init_process(ramdisk_execute_command); 832 printk(KERN_WARNING "Failed to execute %s\n", 833 ramdisk_execute_command); 834 } 835 836 /* 837 * We try each of these until one succeeds. 838 * 839 * The Bourne shell can be used instead of init if we are 840 * trying to recover a really broken machine. 841 */ 842 if (execute_command) { 843 run_init_process(execute_command); 844 printk(KERN_WARNING "Failed to execute %s. Attempting " 845 "defaults...\n", execute_command); 846 } 847 run_init_process("/sbin/init"); 848 run_init_process("/etc/init"); 849 run_init_process("/bin/init"); 850 run_init_process("/bin/sh"); 851 852 panic("No init found. Try passing init= option to kernel. " 853 "See Linux Documentation/init.txt for guidance."); 854 } 855 856 static int __init kernel_init(void * unused) 857 { 858 /* 859 * Wait until kthreadd is all set-up. 860 */ 861 wait_for_completion(&kthreadd_done); 862 /* 863 * init can allocate pages on any node 864 */ 865 set_mems_allowed(node_states[N_HIGH_MEMORY]); 866 /* 867 * init can run on any cpu. 868 */ 869 set_cpus_allowed_ptr(current, cpu_all_mask); 870 /* 871 * Tell the world that we're going to be the grim 872 * reaper of innocent orphaned children. 873 * 874 * We don't want people to have to make incorrect 875 * assumptions about where in the task array this 876 * can be found. 877 */ 878 init_pid_ns.child_reaper = current; 879 880 cad_pid = task_pid(current); 881 882 smp_prepare_cpus(setup_max_cpus); 883 884 do_pre_smp_initcalls(); 885 886 smp_init(); 887 sched_init_smp(); 888 889 do_basic_setup(); 890 891 /* Open the /dev/console on the rootfs, this should never fail */ 892 if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0) 893 printk(KERN_WARNING "Warning: unable to open an initial console.\n"); 894 895 (void) sys_dup(0); 896 (void) sys_dup(0); 897 /* 898 * check if there is an early userspace init. If yes, let it do all 899 * the work 900 */ 901 902 if (!ramdisk_execute_command) 903 ramdisk_execute_command = "/init"; 904 905 if (sys_access((const char __user *) ramdisk_execute_command, 0) != 0) { 906 ramdisk_execute_command = NULL; 907 prepare_namespace(); 908 } 909 910 /* 911 * Ok, we have completed the initial bootup, and 912 * we're essentially up and running. Get rid of the 913 * initmem segments and start the user-mode stuff.. 914 */ 915 916 init_post(); 917 return 0; 918 } 919