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/cgroup.h> 43 #include <linux/efi.h> 44 #include <linux/tick.h> 45 #include <linux/interrupt.h> 46 #include <linux/taskstats_kern.h> 47 #include <linux/delayacct.h> 48 #include <linux/unistd.h> 49 #include <linux/rmap.h> 50 #include <linux/mempolicy.h> 51 #include <linux/key.h> 52 #include <linux/unwind.h> 53 #include <linux/buffer_head.h> 54 #include <linux/debug_locks.h> 55 #include <linux/lockdep.h> 56 #include <linux/pid_namespace.h> 57 #include <linux/device.h> 58 #include <linux/kthread.h> 59 #include <linux/sched.h> 60 61 #include <asm/io.h> 62 #include <asm/bugs.h> 63 #include <asm/setup.h> 64 #include <asm/sections.h> 65 #include <asm/cacheflush.h> 66 67 #ifdef CONFIG_X86_LOCAL_APIC 68 #include <asm/smp.h> 69 #endif 70 71 /* 72 * This is one of the first .c files built. Error out early if we have compiler 73 * trouble. 74 */ 75 76 #if __GNUC__ == 4 && __GNUC_MINOR__ == 1 && __GNUC_PATCHLEVEL__ == 0 77 #warning gcc-4.1.0 is known to miscompile the kernel. A different compiler version is recommended. 78 #endif 79 80 static int kernel_init(void *); 81 82 extern void init_IRQ(void); 83 extern void fork_init(unsigned long); 84 extern void mca_init(void); 85 extern void sbus_init(void); 86 extern void signals_init(void); 87 extern void pidhash_init(void); 88 extern void pidmap_init(void); 89 extern void prio_tree_init(void); 90 extern void radix_tree_init(void); 91 extern void free_initmem(void); 92 #ifdef CONFIG_ACPI 93 extern void acpi_early_init(void); 94 #else 95 static inline void acpi_early_init(void) { } 96 #endif 97 #ifndef CONFIG_DEBUG_RODATA 98 static inline void mark_rodata_ro(void) { } 99 #endif 100 101 #ifdef CONFIG_TC 102 extern void tc_init(void); 103 #endif 104 105 enum system_states system_state; 106 EXPORT_SYMBOL(system_state); 107 108 /* 109 * Boot command-line arguments 110 */ 111 #define MAX_INIT_ARGS CONFIG_INIT_ENV_ARG_LIMIT 112 #define MAX_INIT_ENVS CONFIG_INIT_ENV_ARG_LIMIT 113 114 extern void time_init(void); 115 /* Default late time init is NULL. archs can override this later. */ 116 void (*late_time_init)(void); 117 extern void softirq_init(void); 118 119 /* Untouched command line saved by arch-specific code. */ 120 char __initdata boot_command_line[COMMAND_LINE_SIZE]; 121 /* Untouched saved command line (eg. for /proc) */ 122 char *saved_command_line; 123 /* Command line for parameter parsing */ 124 static char *static_command_line; 125 126 static char *execute_command; 127 static char *ramdisk_execute_command; 128 129 #ifdef CONFIG_SMP 130 /* Setup configured maximum number of CPUs to activate */ 131 unsigned int __initdata setup_max_cpus = NR_CPUS; 132 133 /* 134 * Setup routine for controlling SMP activation 135 * 136 * Command-line option of "nosmp" or "maxcpus=0" will disable SMP 137 * activation entirely (the MPS table probe still happens, though). 138 * 139 * Command-line option of "maxcpus=<NUM>", where <NUM> is an integer 140 * greater than 0, limits the maximum number of CPUs activated in 141 * SMP mode to <NUM>. 142 */ 143 #ifndef CONFIG_X86_IO_APIC 144 static inline void disable_ioapic_setup(void) {}; 145 #endif 146 147 static int __init nosmp(char *str) 148 { 149 setup_max_cpus = 0; 150 disable_ioapic_setup(); 151 return 0; 152 } 153 154 early_param("nosmp", nosmp); 155 156 static int __init maxcpus(char *str) 157 { 158 get_option(&str, &setup_max_cpus); 159 if (setup_max_cpus == 0) 160 disable_ioapic_setup(); 161 162 return 0; 163 } 164 165 early_param("maxcpus", maxcpus); 166 #else 167 #define setup_max_cpus NR_CPUS 168 #endif 169 170 /* 171 * If set, this is an indication to the drivers that reset the underlying 172 * device before going ahead with the initialization otherwise driver might 173 * rely on the BIOS and skip the reset operation. 174 * 175 * This is useful if kernel is booting in an unreliable environment. 176 * For ex. kdump situaiton where previous kernel has crashed, BIOS has been 177 * skipped and devices will be in unknown state. 178 */ 179 unsigned int reset_devices; 180 EXPORT_SYMBOL(reset_devices); 181 182 static int __init set_reset_devices(char *str) 183 { 184 reset_devices = 1; 185 return 1; 186 } 187 188 __setup("reset_devices", set_reset_devices); 189 190 static char * argv_init[MAX_INIT_ARGS+2] = { "init", NULL, }; 191 char * envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, }; 192 static const char *panic_later, *panic_param; 193 194 extern struct obs_kernel_param __setup_start[], __setup_end[]; 195 196 static int __init obsolete_checksetup(char *line) 197 { 198 struct obs_kernel_param *p; 199 int had_early_param = 0; 200 201 p = __setup_start; 202 do { 203 int n = strlen(p->str); 204 if (!strncmp(line, p->str, n)) { 205 if (p->early) { 206 /* Already done in parse_early_param? 207 * (Needs exact match on param part). 208 * Keep iterating, as we can have early 209 * params and __setups of same names 8( */ 210 if (line[n] == '\0' || line[n] == '=') 211 had_early_param = 1; 212 } else if (!p->setup_func) { 213 printk(KERN_WARNING "Parameter %s is obsolete," 214 " ignored\n", p->str); 215 return 1; 216 } else if (p->setup_func(line + n)) 217 return 1; 218 } 219 p++; 220 } while (p < __setup_end); 221 222 return had_early_param; 223 } 224 225 /* 226 * This should be approx 2 Bo*oMips to start (note initial shift), and will 227 * still work even if initially too large, it will just take slightly longer 228 */ 229 unsigned long loops_per_jiffy = (1<<12); 230 231 EXPORT_SYMBOL(loops_per_jiffy); 232 233 static int __init debug_kernel(char *str) 234 { 235 if (*str) 236 return 0; 237 console_loglevel = 10; 238 return 1; 239 } 240 241 static int __init quiet_kernel(char *str) 242 { 243 if (*str) 244 return 0; 245 console_loglevel = 4; 246 return 1; 247 } 248 249 __setup("debug", debug_kernel); 250 __setup("quiet", quiet_kernel); 251 252 static int __init loglevel(char *str) 253 { 254 get_option(&str, &console_loglevel); 255 return 1; 256 } 257 258 __setup("loglevel=", loglevel); 259 260 /* 261 * Unknown boot options get handed to init, unless they look like 262 * failed parameters 263 */ 264 static int __init unknown_bootoption(char *param, char *val) 265 { 266 /* Change NUL term back to "=", to make "param" the whole string. */ 267 if (val) { 268 /* param=val or param="val"? */ 269 if (val == param+strlen(param)+1) 270 val[-1] = '='; 271 else if (val == param+strlen(param)+2) { 272 val[-2] = '='; 273 memmove(val-1, val, strlen(val)+1); 274 val--; 275 } else 276 BUG(); 277 } 278 279 /* Handle obsolete-style parameters */ 280 if (obsolete_checksetup(param)) 281 return 0; 282 283 /* 284 * Preemptive maintenance for "why didn't my misspelled command 285 * line work?" 286 */ 287 if (strchr(param, '.') && (!val || strchr(param, '.') < val)) { 288 printk(KERN_ERR "Unknown boot option `%s': ignoring\n", param); 289 return 0; 290 } 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_per_cpu_areas(void) { } 366 static inline void smp_prepare_cpus(unsigned int maxcpus) { } 367 368 #else 369 370 #ifndef CONFIG_HAVE_SETUP_PER_CPU_AREA 371 unsigned long __per_cpu_offset[NR_CPUS] __read_mostly; 372 373 EXPORT_SYMBOL(__per_cpu_offset); 374 375 static void __init setup_per_cpu_areas(void) 376 { 377 unsigned long size, i; 378 char *ptr; 379 unsigned long nr_possible_cpus = num_possible_cpus(); 380 381 /* Copy section for each CPU (we discard the original) */ 382 size = ALIGN(PERCPU_ENOUGH_ROOM, PAGE_SIZE); 383 ptr = alloc_bootmem_pages(size * nr_possible_cpus); 384 385 for_each_possible_cpu(i) { 386 __per_cpu_offset[i] = ptr - __per_cpu_start; 387 memcpy(ptr, __per_cpu_start, __per_cpu_end - __per_cpu_start); 388 ptr += size; 389 } 390 } 391 #endif /* CONFIG_HAVE_SETUP_PER_CPU_AREA */ 392 393 /* Called by boot processor to activate the rest. */ 394 static void __init smp_init(void) 395 { 396 unsigned int cpu; 397 398 /* FIXME: This should be done in userspace --RR */ 399 for_each_present_cpu(cpu) { 400 if (num_online_cpus() >= setup_max_cpus) 401 break; 402 if (!cpu_online(cpu)) 403 cpu_up(cpu); 404 } 405 406 /* Any cleanup work */ 407 printk(KERN_INFO "Brought up %ld CPUs\n", (long)num_online_cpus()); 408 smp_cpus_done(setup_max_cpus); 409 } 410 411 #endif 412 413 /* 414 * We need to store the untouched command line for future reference. 415 * We also need to store the touched command line since the parameter 416 * parsing is performed in place, and we should allow a component to 417 * store reference of name/value for future reference. 418 */ 419 static void __init setup_command_line(char *command_line) 420 { 421 saved_command_line = alloc_bootmem(strlen (boot_command_line)+1); 422 static_command_line = alloc_bootmem(strlen (command_line)+1); 423 strcpy (saved_command_line, boot_command_line); 424 strcpy (static_command_line, command_line); 425 } 426 427 /* 428 * We need to finalize in a non-__init function or else race conditions 429 * between the root thread and the init thread may cause start_kernel to 430 * be reaped by free_initmem before the root thread has proceeded to 431 * cpu_idle. 432 * 433 * gcc-3.4 accidentally inlines this function, so use noinline. 434 */ 435 436 static void noinline __init_refok rest_init(void) 437 __releases(kernel_lock) 438 { 439 int pid; 440 441 kernel_thread(kernel_init, NULL, CLONE_FS | CLONE_SIGHAND); 442 numa_default_policy(); 443 pid = kernel_thread(kthreadd, NULL, CLONE_FS | CLONE_FILES); 444 kthreadd_task = find_task_by_pid(pid); 445 unlock_kernel(); 446 447 /* 448 * The boot idle thread must execute schedule() 449 * at least once to get things moving: 450 */ 451 init_idle_bootup_task(current); 452 preempt_enable_no_resched(); 453 schedule(); 454 preempt_disable(); 455 456 /* Call into cpu_idle with preempt disabled */ 457 cpu_idle(); 458 } 459 460 /* Check for early params. */ 461 static int __init do_early_param(char *param, char *val) 462 { 463 struct obs_kernel_param *p; 464 465 for (p = __setup_start; p < __setup_end; p++) { 466 if ((p->early && strcmp(param, p->str) == 0) || 467 (strcmp(param, "console") == 0 && 468 strcmp(p->str, "earlycon") == 0) 469 ) { 470 if (p->setup_func(val) != 0) 471 printk(KERN_WARNING 472 "Malformed early option '%s'\n", param); 473 } 474 } 475 /* We accept everything at this stage. */ 476 return 0; 477 } 478 479 /* Arch code calls this early on, or if not, just before other parsing. */ 480 void __init parse_early_param(void) 481 { 482 static __initdata int done = 0; 483 static __initdata char tmp_cmdline[COMMAND_LINE_SIZE]; 484 485 if (done) 486 return; 487 488 /* All fall through to do_early_param. */ 489 strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE); 490 parse_args("early options", tmp_cmdline, NULL, 0, do_early_param); 491 done = 1; 492 } 493 494 /* 495 * Activate the first processor. 496 */ 497 498 static void __init boot_cpu_init(void) 499 { 500 int cpu = smp_processor_id(); 501 /* Mark the boot cpu "present", "online" etc for SMP and UP case */ 502 cpu_set(cpu, cpu_online_map); 503 cpu_set(cpu, cpu_present_map); 504 cpu_set(cpu, cpu_possible_map); 505 } 506 507 void __init __attribute__((weak)) smp_setup_processor_id(void) 508 { 509 } 510 511 asmlinkage void __init start_kernel(void) 512 { 513 char * command_line; 514 extern struct kernel_param __start___param[], __stop___param[]; 515 516 smp_setup_processor_id(); 517 518 /* 519 * Need to run as early as possible, to initialize the 520 * lockdep hash: 521 */ 522 unwind_init(); 523 lockdep_init(); 524 cgroup_init_early(); 525 526 local_irq_disable(); 527 early_boot_irqs_off(); 528 early_init_irq_lock_class(); 529 530 /* 531 * Interrupts are still disabled. Do necessary setups, then 532 * enable them 533 */ 534 lock_kernel(); 535 tick_init(); 536 boot_cpu_init(); 537 page_address_init(); 538 printk(KERN_NOTICE); 539 printk(linux_banner); 540 setup_arch(&command_line); 541 setup_command_line(command_line); 542 unwind_setup(); 543 setup_per_cpu_areas(); 544 smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */ 545 546 /* 547 * Set up the scheduler prior starting any interrupts (such as the 548 * timer interrupt). Full topology setup happens at smp_init() 549 * time - but meanwhile we still have a functioning scheduler. 550 */ 551 sched_init(); 552 /* 553 * Disable preemption - early bootup scheduling is extremely 554 * fragile until we cpu_idle() for the first time. 555 */ 556 preempt_disable(); 557 build_all_zonelists(); 558 page_alloc_init(); 559 enable_debug_pagealloc(); 560 printk(KERN_NOTICE "Kernel command line: %s\n", boot_command_line); 561 parse_early_param(); 562 parse_args("Booting kernel", static_command_line, __start___param, 563 __stop___param - __start___param, 564 &unknown_bootoption); 565 if (!irqs_disabled()) { 566 printk(KERN_WARNING "start_kernel(): bug: interrupts were " 567 "enabled *very* early, fixing it\n"); 568 local_irq_disable(); 569 } 570 sort_main_extable(); 571 trap_init(); 572 rcu_init(); 573 init_IRQ(); 574 pidhash_init(); 575 init_timers(); 576 hrtimers_init(); 577 softirq_init(); 578 timekeeping_init(); 579 time_init(); 580 profile_init(); 581 if (!irqs_disabled()) 582 printk("start_kernel(): bug: interrupts were enabled early\n"); 583 early_boot_irqs_on(); 584 local_irq_enable(); 585 586 /* 587 * HACK ALERT! This is early. We're enabling the console before 588 * we've done PCI setups etc, and console_init() must be aware of 589 * this. But we do want output early, in case something goes wrong. 590 */ 591 console_init(); 592 if (panic_later) 593 panic(panic_later, panic_param); 594 595 lockdep_info(); 596 597 /* 598 * Need to run this when irqs are enabled, because it wants 599 * to self-test [hard/soft]-irqs on/off lock inversion bugs 600 * too: 601 */ 602 locking_selftest(); 603 604 #ifdef CONFIG_BLK_DEV_INITRD 605 if (initrd_start && !initrd_below_start_ok && 606 initrd_start < min_low_pfn << PAGE_SHIFT) { 607 printk(KERN_CRIT "initrd overwritten (0x%08lx < 0x%08lx) - " 608 "disabling it.\n",initrd_start,min_low_pfn << PAGE_SHIFT); 609 initrd_start = 0; 610 } 611 #endif 612 vfs_caches_init_early(); 613 cpuset_init_early(); 614 mem_init(); 615 cpu_hotplug_init(); 616 kmem_cache_init(); 617 setup_per_cpu_pageset(); 618 numa_policy_init(); 619 if (late_time_init) 620 late_time_init(); 621 calibrate_delay(); 622 pidmap_init(); 623 pgtable_cache_init(); 624 prio_tree_init(); 625 anon_vma_init(); 626 #ifdef CONFIG_X86 627 if (efi_enabled) 628 efi_enter_virtual_mode(); 629 #endif 630 fork_init(num_physpages); 631 proc_caches_init(); 632 buffer_init(); 633 unnamed_dev_init(); 634 key_init(); 635 security_init(); 636 vfs_caches_init(num_physpages); 637 radix_tree_init(); 638 signals_init(); 639 /* rootfs populating might need page-writeback */ 640 page_writeback_init(); 641 #ifdef CONFIG_PROC_FS 642 proc_root_init(); 643 #endif 644 cgroup_init(); 645 cpuset_init(); 646 taskstats_init_early(); 647 delayacct_init(); 648 649 check_bugs(); 650 651 acpi_early_init(); /* before LAPIC and SMP init */ 652 653 /* Do the rest non-__init'ed, we're now alive */ 654 rest_init(); 655 } 656 657 static int __initdata initcall_debug; 658 659 static int __init initcall_debug_setup(char *str) 660 { 661 initcall_debug = 1; 662 return 1; 663 } 664 __setup("initcall_debug", initcall_debug_setup); 665 666 extern initcall_t __initcall_start[], __initcall_end[]; 667 668 static void __init do_initcalls(void) 669 { 670 initcall_t *call; 671 int count = preempt_count(); 672 673 for (call = __initcall_start; call < __initcall_end; call++) { 674 ktime_t t0, t1, delta; 675 char *msg = NULL; 676 char msgbuf[40]; 677 int result; 678 679 if (initcall_debug) { 680 printk("Calling initcall 0x%p", *call); 681 print_fn_descriptor_symbol(": %s()", 682 (unsigned long) *call); 683 printk("\n"); 684 t0 = ktime_get(); 685 } 686 687 result = (*call)(); 688 689 if (initcall_debug) { 690 t1 = ktime_get(); 691 delta = ktime_sub(t1, t0); 692 693 printk("initcall 0x%p", *call); 694 print_fn_descriptor_symbol(": %s()", 695 (unsigned long) *call); 696 printk(" returned %d.\n", result); 697 698 printk("initcall 0x%p ran for %Ld msecs: ", 699 *call, (unsigned long long)delta.tv64 >> 20); 700 print_fn_descriptor_symbol("%s()\n", 701 (unsigned long) *call); 702 } 703 704 if (result && result != -ENODEV && initcall_debug) { 705 sprintf(msgbuf, "error code %d", result); 706 msg = msgbuf; 707 } 708 if (preempt_count() != count) { 709 msg = "preemption imbalance"; 710 preempt_count() = count; 711 } 712 if (irqs_disabled()) { 713 msg = "disabled interrupts"; 714 local_irq_enable(); 715 } 716 if (msg) { 717 printk(KERN_WARNING "initcall at 0x%p", *call); 718 print_fn_descriptor_symbol(": %s()", 719 (unsigned long) *call); 720 printk(": returned with %s\n", msg); 721 } 722 } 723 724 /* Make sure there is no pending stuff from the initcall sequence */ 725 flush_scheduled_work(); 726 } 727 728 /* 729 * Ok, the machine is now initialized. None of the devices 730 * have been touched yet, but the CPU subsystem is up and 731 * running, and memory and process management works. 732 * 733 * Now we can finally start doing some real work.. 734 */ 735 static void __init do_basic_setup(void) 736 { 737 /* drivers will send hotplug events */ 738 init_workqueues(); 739 usermodehelper_init(); 740 driver_init(); 741 init_irq_proc(); 742 do_initcalls(); 743 } 744 745 static int __initdata nosoftlockup; 746 747 static int __init nosoftlockup_setup(char *str) 748 { 749 nosoftlockup = 1; 750 return 1; 751 } 752 __setup("nosoftlockup", nosoftlockup_setup); 753 754 static void __init do_pre_smp_initcalls(void) 755 { 756 extern int spawn_ksoftirqd(void); 757 758 migration_init(); 759 spawn_ksoftirqd(); 760 if (!nosoftlockup) 761 spawn_softlockup_task(); 762 } 763 764 static void run_init_process(char *init_filename) 765 { 766 argv_init[0] = init_filename; 767 kernel_execve(init_filename, argv_init, envp_init); 768 } 769 770 /* This is a non __init function. Force it to be noinline otherwise gcc 771 * makes it inline to init() and it becomes part of init.text section 772 */ 773 static int noinline init_post(void) 774 { 775 free_initmem(); 776 unlock_kernel(); 777 mark_rodata_ro(); 778 system_state = SYSTEM_RUNNING; 779 numa_default_policy(); 780 781 if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0) 782 printk(KERN_WARNING "Warning: unable to open an initial console.\n"); 783 784 (void) sys_dup(0); 785 (void) sys_dup(0); 786 787 if (ramdisk_execute_command) { 788 run_init_process(ramdisk_execute_command); 789 printk(KERN_WARNING "Failed to execute %s\n", 790 ramdisk_execute_command); 791 } 792 793 /* 794 * We try each of these until one succeeds. 795 * 796 * The Bourne shell can be used instead of init if we are 797 * trying to recover a really broken machine. 798 */ 799 if (execute_command) { 800 run_init_process(execute_command); 801 printk(KERN_WARNING "Failed to execute %s. Attempting " 802 "defaults...\n", execute_command); 803 } 804 run_init_process("/sbin/init"); 805 run_init_process("/etc/init"); 806 run_init_process("/bin/init"); 807 run_init_process("/bin/sh"); 808 809 panic("No init found. Try passing init= option to kernel."); 810 } 811 812 static int __init kernel_init(void * unused) 813 { 814 lock_kernel(); 815 /* 816 * init can run on any cpu. 817 */ 818 set_cpus_allowed(current, CPU_MASK_ALL); 819 /* 820 * Tell the world that we're going to be the grim 821 * reaper of innocent orphaned children. 822 * 823 * We don't want people to have to make incorrect 824 * assumptions about where in the task array this 825 * can be found. 826 */ 827 init_pid_ns.child_reaper = current; 828 829 __set_special_pids(1, 1); 830 cad_pid = task_pid(current); 831 832 smp_prepare_cpus(setup_max_cpus); 833 834 do_pre_smp_initcalls(); 835 836 smp_init(); 837 sched_init_smp(); 838 839 cpuset_init_smp(); 840 841 do_basic_setup(); 842 843 /* 844 * check if there is an early userspace init. If yes, let it do all 845 * the work 846 */ 847 848 if (!ramdisk_execute_command) 849 ramdisk_execute_command = "/init"; 850 851 if (sys_access((const char __user *) ramdisk_execute_command, 0) != 0) { 852 ramdisk_execute_command = NULL; 853 prepare_namespace(); 854 } 855 856 /* 857 * Ok, we have completed the initial bootup, and 858 * we're essentially up and running. Get rid of the 859 * initmem segments and start the user-mode stuff.. 860 */ 861 init_post(); 862 return 0; 863 } 864