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/string.h> 18 #include <linux/ctype.h> 19 #include <linux/delay.h> 20 #include <linux/utsname.h> 21 #include <linux/ioport.h> 22 #include <linux/init.h> 23 #include <linux/smp_lock.h> 24 #include <linux/initrd.h> 25 #include <linux/hdreg.h> 26 #include <linux/bootmem.h> 27 #include <linux/tty.h> 28 #include <linux/gfp.h> 29 #include <linux/percpu.h> 30 #include <linux/kmod.h> 31 #include <linux/kernel_stat.h> 32 #include <linux/start_kernel.h> 33 #include <linux/security.h> 34 #include <linux/workqueue.h> 35 #include <linux/profile.h> 36 #include <linux/rcupdate.h> 37 #include <linux/moduleparam.h> 38 #include <linux/kallsyms.h> 39 #include <linux/writeback.h> 40 #include <linux/cpu.h> 41 #include <linux/cpuset.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/unwind.h> 52 #include <linux/buffer_head.h> 53 #include <linux/debug_locks.h> 54 #include <linux/lockdep.h> 55 #include <linux/pid_namespace.h> 56 #include <linux/device.h> 57 #include <linux/kthread.h> 58 59 #include <asm/io.h> 60 #include <asm/bugs.h> 61 #include <asm/setup.h> 62 #include <asm/sections.h> 63 #include <asm/cacheflush.h> 64 65 #ifdef CONFIG_X86_LOCAL_APIC 66 #include <asm/smp.h> 67 #endif 68 69 /* 70 * This is one of the first .c files built. Error out early if we have compiler 71 * trouble. 72 * 73 * Versions of gcc older than that listed below may actually compile and link 74 * okay, but the end product can have subtle run time bugs. To avoid associated 75 * bogus bug reports, we flatly refuse to compile with a gcc that is known to be 76 * too old from the very beginning. 77 */ 78 #if (__GNUC__ < 3) || (__GNUC__ == 3 && __GNUC_MINOR__ < 2) 79 #error Sorry, your GCC is too old. It builds incorrect kernels. 80 #endif 81 82 #if __GNUC__ == 4 && __GNUC_MINOR__ == 1 && __GNUC_PATCHLEVEL__ == 0 83 #warning gcc-4.1.0 is known to miscompile the kernel. A different compiler version is recommended. 84 #endif 85 86 static int kernel_init(void *); 87 88 extern void init_IRQ(void); 89 extern void fork_init(unsigned long); 90 extern void mca_init(void); 91 extern void sbus_init(void); 92 extern void signals_init(void); 93 extern void pidhash_init(void); 94 extern void pidmap_init(void); 95 extern void prio_tree_init(void); 96 extern void radix_tree_init(void); 97 extern void free_initmem(void); 98 #ifdef CONFIG_ACPI 99 extern void acpi_early_init(void); 100 #else 101 static inline void acpi_early_init(void) { } 102 #endif 103 #ifndef CONFIG_DEBUG_RODATA 104 static inline void mark_rodata_ro(void) { } 105 #endif 106 107 #ifdef CONFIG_TC 108 extern void tc_init(void); 109 #endif 110 111 enum system_states system_state; 112 EXPORT_SYMBOL(system_state); 113 114 /* 115 * Boot command-line arguments 116 */ 117 #define MAX_INIT_ARGS CONFIG_INIT_ENV_ARG_LIMIT 118 #define MAX_INIT_ENVS CONFIG_INIT_ENV_ARG_LIMIT 119 120 extern void time_init(void); 121 /* Default late time init is NULL. archs can override this later. */ 122 void (*late_time_init)(void); 123 extern void softirq_init(void); 124 125 /* Untouched command line saved by arch-specific code. */ 126 char __initdata boot_command_line[COMMAND_LINE_SIZE]; 127 /* Untouched saved command line (eg. for /proc) */ 128 char *saved_command_line; 129 /* Command line for parameter parsing */ 130 static char *static_command_line; 131 132 static char *execute_command; 133 static char *ramdisk_execute_command; 134 135 /* Setup configured maximum number of CPUs to activate */ 136 static unsigned int max_cpus = NR_CPUS; 137 138 /* 139 * If set, this is an indication to the drivers that reset the underlying 140 * device before going ahead with the initialization otherwise driver might 141 * rely on the BIOS and skip the reset operation. 142 * 143 * This is useful if kernel is booting in an unreliable environment. 144 * For ex. kdump situaiton where previous kernel has crashed, BIOS has been 145 * skipped and devices will be in unknown state. 146 */ 147 unsigned int reset_devices; 148 EXPORT_SYMBOL(reset_devices); 149 150 /* 151 * Setup routine for controlling SMP activation 152 * 153 * Command-line option of "nosmp" or "maxcpus=0" will disable SMP 154 * activation entirely (the MPS table probe still happens, though). 155 * 156 * Command-line option of "maxcpus=<NUM>", where <NUM> is an integer 157 * greater than 0, limits the maximum number of CPUs activated in 158 * SMP mode to <NUM>. 159 */ 160 static int __init nosmp(char *str) 161 { 162 max_cpus = 0; 163 return 1; 164 } 165 166 __setup("nosmp", nosmp); 167 168 static int __init maxcpus(char *str) 169 { 170 get_option(&str, &max_cpus); 171 return 1; 172 } 173 174 __setup("maxcpus=", maxcpus); 175 176 static int __init set_reset_devices(char *str) 177 { 178 reset_devices = 1; 179 return 1; 180 } 181 182 __setup("reset_devices", set_reset_devices); 183 184 static char * argv_init[MAX_INIT_ARGS+2] = { "init", NULL, }; 185 char * envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, }; 186 static const char *panic_later, *panic_param; 187 188 extern struct obs_kernel_param __setup_start[], __setup_end[]; 189 190 static int __init obsolete_checksetup(char *line) 191 { 192 struct obs_kernel_param *p; 193 int had_early_param = 0; 194 195 p = __setup_start; 196 do { 197 int n = strlen(p->str); 198 if (!strncmp(line, p->str, n)) { 199 if (p->early) { 200 /* Already done in parse_early_param? 201 * (Needs exact match on param part). 202 * Keep iterating, as we can have early 203 * params and __setups of same names 8( */ 204 if (line[n] == '\0' || line[n] == '=') 205 had_early_param = 1; 206 } else if (!p->setup_func) { 207 printk(KERN_WARNING "Parameter %s is obsolete," 208 " ignored\n", p->str); 209 return 1; 210 } else if (p->setup_func(line + n)) 211 return 1; 212 } 213 p++; 214 } while (p < __setup_end); 215 216 return had_early_param; 217 } 218 219 /* 220 * This should be approx 2 Bo*oMips to start (note initial shift), and will 221 * still work even if initially too large, it will just take slightly longer 222 */ 223 unsigned long loops_per_jiffy = (1<<12); 224 225 EXPORT_SYMBOL(loops_per_jiffy); 226 227 static int __init debug_kernel(char *str) 228 { 229 if (*str) 230 return 0; 231 console_loglevel = 10; 232 return 1; 233 } 234 235 static int __init quiet_kernel(char *str) 236 { 237 if (*str) 238 return 0; 239 console_loglevel = 4; 240 return 1; 241 } 242 243 __setup("debug", debug_kernel); 244 __setup("quiet", quiet_kernel); 245 246 static int __init loglevel(char *str) 247 { 248 get_option(&str, &console_loglevel); 249 return 1; 250 } 251 252 __setup("loglevel=", loglevel); 253 254 /* 255 * Unknown boot options get handed to init, unless they look like 256 * failed parameters 257 */ 258 static int __init unknown_bootoption(char *param, char *val) 259 { 260 /* Change NUL term back to "=", to make "param" the whole string. */ 261 if (val) { 262 /* param=val or param="val"? */ 263 if (val == param+strlen(param)+1) 264 val[-1] = '='; 265 else if (val == param+strlen(param)+2) { 266 val[-2] = '='; 267 memmove(val-1, val, strlen(val)+1); 268 val--; 269 } else 270 BUG(); 271 } 272 273 /* Handle obsolete-style parameters */ 274 if (obsolete_checksetup(param)) 275 return 0; 276 277 /* 278 * Preemptive maintenance for "why didn't my mispelled command 279 * line work?" 280 */ 281 if (strchr(param, '.') && (!val || strchr(param, '.') < val)) { 282 printk(KERN_ERR "Unknown boot option `%s': ignoring\n", param); 283 return 0; 284 } 285 286 if (panic_later) 287 return 0; 288 289 if (val) { 290 /* Environment option */ 291 unsigned int i; 292 for (i = 0; envp_init[i]; i++) { 293 if (i == MAX_INIT_ENVS) { 294 panic_later = "Too many boot env vars at `%s'"; 295 panic_param = param; 296 } 297 if (!strncmp(param, envp_init[i], val - param)) 298 break; 299 } 300 envp_init[i] = param; 301 } else { 302 /* Command line option */ 303 unsigned int i; 304 for (i = 0; argv_init[i]; i++) { 305 if (i == MAX_INIT_ARGS) { 306 panic_later = "Too many boot init vars at `%s'"; 307 panic_param = param; 308 } 309 } 310 argv_init[i] = param; 311 } 312 return 0; 313 } 314 315 static int __init init_setup(char *str) 316 { 317 unsigned int i; 318 319 execute_command = str; 320 /* 321 * In case LILO is going to boot us with default command line, 322 * it prepends "auto" before the whole cmdline which makes 323 * the shell think it should execute a script with such name. 324 * So we ignore all arguments entered _before_ init=... [MJ] 325 */ 326 for (i = 1; i < MAX_INIT_ARGS; i++) 327 argv_init[i] = NULL; 328 return 1; 329 } 330 __setup("init=", init_setup); 331 332 static int __init rdinit_setup(char *str) 333 { 334 unsigned int i; 335 336 ramdisk_execute_command = str; 337 /* See "auto" comment in init_setup */ 338 for (i = 1; i < MAX_INIT_ARGS; i++) 339 argv_init[i] = NULL; 340 return 1; 341 } 342 __setup("rdinit=", rdinit_setup); 343 344 #ifndef CONFIG_SMP 345 346 #ifdef CONFIG_X86_LOCAL_APIC 347 static void __init smp_init(void) 348 { 349 APIC_init_uniprocessor(); 350 } 351 #else 352 #define smp_init() do { } while (0) 353 #endif 354 355 static inline void setup_per_cpu_areas(void) { } 356 static inline void smp_prepare_cpus(unsigned int maxcpus) { } 357 358 #else 359 360 #ifdef __GENERIC_PER_CPU 361 unsigned long __per_cpu_offset[NR_CPUS] __read_mostly; 362 363 EXPORT_SYMBOL(__per_cpu_offset); 364 365 static void __init setup_per_cpu_areas(void) 366 { 367 unsigned long size, i; 368 char *ptr; 369 unsigned long nr_possible_cpus = num_possible_cpus(); 370 371 /* Copy section for each CPU (we discard the original) */ 372 size = ALIGN(PERCPU_ENOUGH_ROOM, PAGE_SIZE); 373 ptr = alloc_bootmem_pages(size * nr_possible_cpus); 374 375 for_each_possible_cpu(i) { 376 __per_cpu_offset[i] = ptr - __per_cpu_start; 377 memcpy(ptr, __per_cpu_start, __per_cpu_end - __per_cpu_start); 378 ptr += size; 379 } 380 } 381 #endif /* !__GENERIC_PER_CPU */ 382 383 /* Called by boot processor to activate the rest. */ 384 static void __init smp_init(void) 385 { 386 unsigned int cpu; 387 388 /* FIXME: This should be done in userspace --RR */ 389 for_each_present_cpu(cpu) { 390 if (num_online_cpus() >= max_cpus) 391 break; 392 if (!cpu_online(cpu)) 393 cpu_up(cpu); 394 } 395 396 /* Any cleanup work */ 397 printk(KERN_INFO "Brought up %ld CPUs\n", (long)num_online_cpus()); 398 smp_cpus_done(max_cpus); 399 } 400 401 #endif 402 403 /* 404 * We need to store the untouched command line for future reference. 405 * We also need to store the touched command line since the parameter 406 * parsing is performed in place, and we should allow a component to 407 * store reference of name/value for future reference. 408 */ 409 static void __init setup_command_line(char *command_line) 410 { 411 saved_command_line = alloc_bootmem(strlen (boot_command_line)+1); 412 static_command_line = alloc_bootmem(strlen (command_line)+1); 413 strcpy (saved_command_line, boot_command_line); 414 strcpy (static_command_line, command_line); 415 } 416 417 /* 418 * We need to finalize in a non-__init function or else race conditions 419 * between the root thread and the init thread may cause start_kernel to 420 * be reaped by free_initmem before the root thread has proceeded to 421 * cpu_idle. 422 * 423 * gcc-3.4 accidentally inlines this function, so use noinline. 424 */ 425 426 static void noinline __init_refok rest_init(void) 427 __releases(kernel_lock) 428 { 429 int pid; 430 431 kernel_thread(kernel_init, NULL, CLONE_FS | CLONE_SIGHAND); 432 numa_default_policy(); 433 pid = kernel_thread(kthreadd, NULL, CLONE_FS | CLONE_FILES); 434 kthreadd_task = find_task_by_pid(pid); 435 unlock_kernel(); 436 437 /* 438 * The boot idle thread must execute schedule() 439 * at least once to get things moving: 440 */ 441 init_idle_bootup_task(current); 442 preempt_enable_no_resched(); 443 schedule(); 444 preempt_disable(); 445 446 /* Call into cpu_idle with preempt disabled */ 447 cpu_idle(); 448 } 449 450 /* Check for early params. */ 451 static int __init do_early_param(char *param, char *val) 452 { 453 struct obs_kernel_param *p; 454 455 for (p = __setup_start; p < __setup_end; p++) { 456 if (p->early && strcmp(param, p->str) == 0) { 457 if (p->setup_func(val) != 0) 458 printk(KERN_WARNING 459 "Malformed early option '%s'\n", param); 460 } 461 } 462 /* We accept everything at this stage. */ 463 return 0; 464 } 465 466 /* Arch code calls this early on, or if not, just before other parsing. */ 467 void __init parse_early_param(void) 468 { 469 static __initdata int done = 0; 470 static __initdata char tmp_cmdline[COMMAND_LINE_SIZE]; 471 472 if (done) 473 return; 474 475 /* All fall through to do_early_param. */ 476 strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE); 477 parse_args("early options", tmp_cmdline, NULL, 0, do_early_param); 478 done = 1; 479 } 480 481 /* 482 * Activate the first processor. 483 */ 484 485 static void __init boot_cpu_init(void) 486 { 487 int cpu = smp_processor_id(); 488 /* Mark the boot cpu "present", "online" etc for SMP and UP case */ 489 cpu_set(cpu, cpu_online_map); 490 cpu_set(cpu, cpu_present_map); 491 cpu_set(cpu, cpu_possible_map); 492 } 493 494 void __init __attribute__((weak)) smp_setup_processor_id(void) 495 { 496 } 497 498 asmlinkage void __init start_kernel(void) 499 { 500 char * command_line; 501 extern struct kernel_param __start___param[], __stop___param[]; 502 503 smp_setup_processor_id(); 504 505 /* 506 * Need to run as early as possible, to initialize the 507 * lockdep hash: 508 */ 509 unwind_init(); 510 lockdep_init(); 511 512 local_irq_disable(); 513 early_boot_irqs_off(); 514 early_init_irq_lock_class(); 515 516 /* 517 * Interrupts are still disabled. Do necessary setups, then 518 * enable them 519 */ 520 lock_kernel(); 521 tick_init(); 522 boot_cpu_init(); 523 page_address_init(); 524 printk(KERN_NOTICE); 525 printk(linux_banner); 526 setup_arch(&command_line); 527 setup_command_line(command_line); 528 unwind_setup(); 529 setup_per_cpu_areas(); 530 smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */ 531 532 /* 533 * Set up the scheduler prior starting any interrupts (such as the 534 * timer interrupt). Full topology setup happens at smp_init() 535 * time - but meanwhile we still have a functioning scheduler. 536 */ 537 sched_init(); 538 /* 539 * Disable preemption - early bootup scheduling is extremely 540 * fragile until we cpu_idle() for the first time. 541 */ 542 preempt_disable(); 543 build_all_zonelists(); 544 page_alloc_init(); 545 printk(KERN_NOTICE "Kernel command line: %s\n", boot_command_line); 546 parse_early_param(); 547 parse_args("Booting kernel", static_command_line, __start___param, 548 __stop___param - __start___param, 549 &unknown_bootoption); 550 if (!irqs_disabled()) { 551 printk(KERN_WARNING "start_kernel(): bug: interrupts were " 552 "enabled *very* early, fixing it\n"); 553 local_irq_disable(); 554 } 555 sort_main_extable(); 556 trap_init(); 557 rcu_init(); 558 init_IRQ(); 559 pidhash_init(); 560 init_timers(); 561 hrtimers_init(); 562 softirq_init(); 563 timekeeping_init(); 564 time_init(); 565 profile_init(); 566 if (!irqs_disabled()) 567 printk("start_kernel(): bug: interrupts were enabled early\n"); 568 early_boot_irqs_on(); 569 local_irq_enable(); 570 571 /* 572 * HACK ALERT! This is early. We're enabling the console before 573 * we've done PCI setups etc, and console_init() must be aware of 574 * this. But we do want output early, in case something goes wrong. 575 */ 576 console_init(); 577 if (panic_later) 578 panic(panic_later, panic_param); 579 580 lockdep_info(); 581 582 /* 583 * Need to run this when irqs are enabled, because it wants 584 * to self-test [hard/soft]-irqs on/off lock inversion bugs 585 * too: 586 */ 587 locking_selftest(); 588 589 #ifdef CONFIG_BLK_DEV_INITRD 590 if (initrd_start && !initrd_below_start_ok && 591 initrd_start < min_low_pfn << PAGE_SHIFT) { 592 printk(KERN_CRIT "initrd overwritten (0x%08lx < 0x%08lx) - " 593 "disabling it.\n",initrd_start,min_low_pfn << PAGE_SHIFT); 594 initrd_start = 0; 595 } 596 #endif 597 vfs_caches_init_early(); 598 cpuset_init_early(); 599 mem_init(); 600 kmem_cache_init(); 601 setup_per_cpu_pageset(); 602 numa_policy_init(); 603 if (late_time_init) 604 late_time_init(); 605 calibrate_delay(); 606 pidmap_init(); 607 pgtable_cache_init(); 608 prio_tree_init(); 609 anon_vma_init(); 610 #ifdef CONFIG_X86 611 if (efi_enabled) 612 efi_enter_virtual_mode(); 613 #endif 614 fork_init(num_physpages); 615 proc_caches_init(); 616 buffer_init(); 617 unnamed_dev_init(); 618 key_init(); 619 security_init(); 620 vfs_caches_init(num_physpages); 621 radix_tree_init(); 622 signals_init(); 623 /* rootfs populating might need page-writeback */ 624 page_writeback_init(); 625 #ifdef CONFIG_PROC_FS 626 proc_root_init(); 627 #endif 628 cpuset_init(); 629 taskstats_init_early(); 630 delayacct_init(); 631 632 check_bugs(); 633 634 acpi_early_init(); /* before LAPIC and SMP init */ 635 636 /* Do the rest non-__init'ed, we're now alive */ 637 rest_init(); 638 } 639 640 static int __initdata initcall_debug; 641 642 static int __init initcall_debug_setup(char *str) 643 { 644 initcall_debug = 1; 645 return 1; 646 } 647 __setup("initcall_debug", initcall_debug_setup); 648 649 extern initcall_t __initcall_start[], __initcall_end[]; 650 651 static void __init do_initcalls(void) 652 { 653 initcall_t *call; 654 int count = preempt_count(); 655 656 for (call = __initcall_start; call < __initcall_end; call++) { 657 ktime_t t0, t1, delta; 658 char *msg = NULL; 659 char msgbuf[40]; 660 int result; 661 662 if (initcall_debug) { 663 printk("Calling initcall 0x%p", *call); 664 print_fn_descriptor_symbol(": %s()", 665 (unsigned long) *call); 666 printk("\n"); 667 t0 = ktime_get(); 668 } 669 670 result = (*call)(); 671 672 if (initcall_debug) { 673 t1 = ktime_get(); 674 delta = ktime_sub(t1, t0); 675 676 printk("initcall 0x%p", *call); 677 print_fn_descriptor_symbol(": %s()", 678 (unsigned long) *call); 679 printk(" returned %d.\n", result); 680 681 printk("initcall 0x%p ran for %Ld msecs: ", 682 *call, (unsigned long long)delta.tv64 >> 20); 683 print_fn_descriptor_symbol("%s()\n", 684 (unsigned long) *call); 685 } 686 687 if (result && result != -ENODEV && initcall_debug) { 688 sprintf(msgbuf, "error code %d", result); 689 msg = msgbuf; 690 } 691 if (preempt_count() != count) { 692 msg = "preemption imbalance"; 693 preempt_count() = count; 694 } 695 if (irqs_disabled()) { 696 msg = "disabled interrupts"; 697 local_irq_enable(); 698 } 699 if (msg) { 700 printk(KERN_WARNING "initcall at 0x%p", *call); 701 print_fn_descriptor_symbol(": %s()", 702 (unsigned long) *call); 703 printk(": returned with %s\n", msg); 704 } 705 } 706 707 /* Make sure there is no pending stuff from the initcall sequence */ 708 flush_scheduled_work(); 709 } 710 711 /* 712 * Ok, the machine is now initialized. None of the devices 713 * have been touched yet, but the CPU subsystem is up and 714 * running, and memory and process management works. 715 * 716 * Now we can finally start doing some real work.. 717 */ 718 static void __init do_basic_setup(void) 719 { 720 /* drivers will send hotplug events */ 721 init_workqueues(); 722 usermodehelper_init(); 723 driver_init(); 724 init_irq_proc(); 725 do_initcalls(); 726 } 727 728 static void __init do_pre_smp_initcalls(void) 729 { 730 extern int spawn_ksoftirqd(void); 731 #ifdef CONFIG_SMP 732 extern int migration_init(void); 733 734 migration_init(); 735 #endif 736 spawn_ksoftirqd(); 737 spawn_softlockup_task(); 738 } 739 740 static void run_init_process(char *init_filename) 741 { 742 argv_init[0] = init_filename; 743 kernel_execve(init_filename, argv_init, envp_init); 744 } 745 746 /* This is a non __init function. Force it to be noinline otherwise gcc 747 * makes it inline to init() and it becomes part of init.text section 748 */ 749 static int noinline init_post(void) 750 { 751 free_initmem(); 752 unlock_kernel(); 753 mark_rodata_ro(); 754 system_state = SYSTEM_RUNNING; 755 numa_default_policy(); 756 757 if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0) 758 printk(KERN_WARNING "Warning: unable to open an initial console.\n"); 759 760 (void) sys_dup(0); 761 (void) sys_dup(0); 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 } 787 788 static int __init kernel_init(void * unused) 789 { 790 lock_kernel(); 791 /* 792 * init can run on any cpu. 793 */ 794 set_cpus_allowed(current, CPU_MASK_ALL); 795 /* 796 * Tell the world that we're going to be the grim 797 * reaper of innocent orphaned children. 798 * 799 * We don't want people to have to make incorrect 800 * assumptions about where in the task array this 801 * can be found. 802 */ 803 init_pid_ns.child_reaper = current; 804 805 __set_special_pids(1, 1); 806 cad_pid = task_pid(current); 807 808 smp_prepare_cpus(max_cpus); 809 810 do_pre_smp_initcalls(); 811 812 smp_init(); 813 sched_init_smp(); 814 815 cpuset_init_smp(); 816 817 do_basic_setup(); 818 819 /* 820 * check if there is an early userspace init. If yes, let it do all 821 * the work 822 */ 823 824 if (!ramdisk_execute_command) 825 ramdisk_execute_command = "/init"; 826 827 if (sys_access((const char __user *) ramdisk_execute_command, 0) != 0) { 828 ramdisk_execute_command = NULL; 829 prepare_namespace(); 830 } 831 832 /* 833 * Ok, we have completed the initial bootup, and 834 * we're essentially up and running. Get rid of the 835 * initmem segments and start the user-mode stuff.. 836 */ 837 init_post(); 838 return 0; 839 } 840