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