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 #include <linux/signal.h> 61 62 #include <asm/io.h> 63 #include <asm/bugs.h> 64 #include <asm/setup.h> 65 #include <asm/sections.h> 66 #include <asm/cacheflush.h> 67 68 #ifdef CONFIG_X86_LOCAL_APIC 69 #include <asm/smp.h> 70 #endif 71 72 /* 73 * This is one of the first .c files built. Error out early if we have compiler 74 * trouble. 75 */ 76 77 #if __GNUC__ == 4 && __GNUC_MINOR__ == 1 && __GNUC_PATCHLEVEL__ == 0 78 #warning gcc-4.1.0 is known to miscompile the kernel. A different compiler version is recommended. 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 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 #ifdef CONFIG_ACPI_CUSTOM_DSDT_INITRD 106 extern int populate_rootfs(void); 107 #else 108 static inline void populate_rootfs(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 #ifdef CONFIG_SMP 136 /* Setup configured maximum number of CPUs to activate */ 137 unsigned int __initdata setup_max_cpus = NR_CPUS; 138 139 /* 140 * Setup routine for controlling SMP activation 141 * 142 * Command-line option of "nosmp" or "maxcpus=0" will disable SMP 143 * activation entirely (the MPS table probe still happens, though). 144 * 145 * Command-line option of "maxcpus=<NUM>", where <NUM> is an integer 146 * greater than 0, limits the maximum number of CPUs activated in 147 * SMP mode to <NUM>. 148 */ 149 #ifndef CONFIG_X86_IO_APIC 150 static inline void disable_ioapic_setup(void) {}; 151 #endif 152 153 static int __init nosmp(char *str) 154 { 155 setup_max_cpus = 0; 156 disable_ioapic_setup(); 157 return 0; 158 } 159 160 early_param("nosmp", nosmp); 161 162 static int __init maxcpus(char *str) 163 { 164 get_option(&str, &setup_max_cpus); 165 if (setup_max_cpus == 0) 166 disable_ioapic_setup(); 167 168 return 0; 169 } 170 171 early_param("maxcpus", maxcpus); 172 #else 173 #define setup_max_cpus NR_CPUS 174 #endif 175 176 /* 177 * If set, this is an indication to the drivers that reset the underlying 178 * device before going ahead with the initialization otherwise driver might 179 * rely on the BIOS and skip the reset operation. 180 * 181 * This is useful if kernel is booting in an unreliable environment. 182 * For ex. kdump situaiton where previous kernel has crashed, BIOS has been 183 * skipped and devices will be in unknown state. 184 */ 185 unsigned int reset_devices; 186 EXPORT_SYMBOL(reset_devices); 187 188 static int __init set_reset_devices(char *str) 189 { 190 reset_devices = 1; 191 return 1; 192 } 193 194 __setup("reset_devices", set_reset_devices); 195 196 static char * argv_init[MAX_INIT_ARGS+2] = { "init", NULL, }; 197 char * envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, }; 198 static const char *panic_later, *panic_param; 199 200 extern struct obs_kernel_param __setup_start[], __setup_end[]; 201 202 static int __init obsolete_checksetup(char *line) 203 { 204 struct obs_kernel_param *p; 205 int had_early_param = 0; 206 207 p = __setup_start; 208 do { 209 int n = strlen(p->str); 210 if (!strncmp(line, p->str, n)) { 211 if (p->early) { 212 /* Already done in parse_early_param? 213 * (Needs exact match on param part). 214 * Keep iterating, as we can have early 215 * params and __setups of same names 8( */ 216 if (line[n] == '\0' || line[n] == '=') 217 had_early_param = 1; 218 } else if (!p->setup_func) { 219 printk(KERN_WARNING "Parameter %s is obsolete," 220 " ignored\n", p->str); 221 return 1; 222 } else if (p->setup_func(line + n)) 223 return 1; 224 } 225 p++; 226 } while (p < __setup_end); 227 228 return had_early_param; 229 } 230 231 /* 232 * This should be approx 2 Bo*oMips to start (note initial shift), and will 233 * still work even if initially too large, it will just take slightly longer 234 */ 235 unsigned long loops_per_jiffy = (1<<12); 236 237 EXPORT_SYMBOL(loops_per_jiffy); 238 239 static int __init debug_kernel(char *str) 240 { 241 console_loglevel = 10; 242 return 0; 243 } 244 245 static int __init quiet_kernel(char *str) 246 { 247 console_loglevel = 4; 248 return 0; 249 } 250 251 early_param("debug", debug_kernel); 252 early_param("quiet", quiet_kernel); 253 254 static int __init loglevel(char *str) 255 { 256 get_option(&str, &console_loglevel); 257 return 1; 258 } 259 260 early_param("loglevel", loglevel); 261 262 /* 263 * Unknown boot options get handed to init, unless they look like 264 * failed parameters 265 */ 266 static int __init unknown_bootoption(char *param, char *val) 267 { 268 /* Change NUL term back to "=", to make "param" the whole string. */ 269 if (val) { 270 /* param=val or param="val"? */ 271 if (val == param+strlen(param)+1) 272 val[-1] = '='; 273 else if (val == param+strlen(param)+2) { 274 val[-2] = '='; 275 memmove(val-1, val, strlen(val)+1); 276 val--; 277 } else 278 BUG(); 279 } 280 281 /* Handle obsolete-style parameters */ 282 if (obsolete_checksetup(param)) 283 return 0; 284 285 /* 286 * Preemptive maintenance for "why didn't my misspelled command 287 * line work?" 288 */ 289 if (strchr(param, '.') && (!val || strchr(param, '.') < val)) { 290 printk(KERN_ERR "Unknown boot option `%s': ignoring\n", param); 291 return 0; 292 } 293 294 if (panic_later) 295 return 0; 296 297 if (val) { 298 /* Environment option */ 299 unsigned int i; 300 for (i = 0; envp_init[i]; i++) { 301 if (i == MAX_INIT_ENVS) { 302 panic_later = "Too many boot env vars at `%s'"; 303 panic_param = param; 304 } 305 if (!strncmp(param, envp_init[i], val - param)) 306 break; 307 } 308 envp_init[i] = param; 309 } else { 310 /* Command line option */ 311 unsigned int i; 312 for (i = 0; argv_init[i]; i++) { 313 if (i == MAX_INIT_ARGS) { 314 panic_later = "Too many boot init vars at `%s'"; 315 panic_param = param; 316 } 317 } 318 argv_init[i] = param; 319 } 320 return 0; 321 } 322 323 #ifdef CONFIG_DEBUG_PAGEALLOC 324 int __read_mostly debug_pagealloc_enabled = 0; 325 #endif 326 327 static int __init init_setup(char *str) 328 { 329 unsigned int i; 330 331 execute_command = str; 332 /* 333 * In case LILO is going to boot us with default command line, 334 * it prepends "auto" before the whole cmdline which makes 335 * the shell think it should execute a script with such name. 336 * So we ignore all arguments entered _before_ init=... [MJ] 337 */ 338 for (i = 1; i < MAX_INIT_ARGS; i++) 339 argv_init[i] = NULL; 340 return 1; 341 } 342 __setup("init=", init_setup); 343 344 static int __init rdinit_setup(char *str) 345 { 346 unsigned int i; 347 348 ramdisk_execute_command = str; 349 /* See "auto" comment in init_setup */ 350 for (i = 1; i < MAX_INIT_ARGS; i++) 351 argv_init[i] = NULL; 352 return 1; 353 } 354 __setup("rdinit=", rdinit_setup); 355 356 #ifndef CONFIG_SMP 357 358 #ifdef CONFIG_X86_LOCAL_APIC 359 static void __init smp_init(void) 360 { 361 APIC_init_uniprocessor(); 362 } 363 #else 364 #define smp_init() do { } while (0) 365 #endif 366 367 static inline void setup_per_cpu_areas(void) { } 368 static inline void smp_prepare_cpus(unsigned int maxcpus) { } 369 370 #else 371 372 #ifndef CONFIG_HAVE_SETUP_PER_CPU_AREA 373 unsigned long __per_cpu_offset[NR_CPUS] __read_mostly; 374 375 EXPORT_SYMBOL(__per_cpu_offset); 376 377 static void __init setup_per_cpu_areas(void) 378 { 379 unsigned long size, i; 380 char *ptr; 381 unsigned long nr_possible_cpus = num_possible_cpus(); 382 383 /* Copy section for each CPU (we discard the original) */ 384 size = ALIGN(PERCPU_ENOUGH_ROOM, PAGE_SIZE); 385 ptr = alloc_bootmem_pages(size * nr_possible_cpus); 386 387 for_each_possible_cpu(i) { 388 __per_cpu_offset[i] = ptr - __per_cpu_start; 389 memcpy(ptr, __per_cpu_start, __per_cpu_end - __per_cpu_start); 390 ptr += size; 391 } 392 } 393 #endif /* CONFIG_HAVE_SETUP_PER_CPU_AREA */ 394 395 /* Called by boot processor to activate the rest. */ 396 static void __init smp_init(void) 397 { 398 unsigned int cpu; 399 400 /* FIXME: This should be done in userspace --RR */ 401 for_each_present_cpu(cpu) { 402 if (num_online_cpus() >= setup_max_cpus) 403 break; 404 if (!cpu_online(cpu)) 405 cpu_up(cpu); 406 } 407 408 /* Any cleanup work */ 409 printk(KERN_INFO "Brought up %ld CPUs\n", (long)num_online_cpus()); 410 smp_cpus_done(setup_max_cpus); 411 } 412 413 #endif 414 415 /* 416 * We need to store the untouched command line for future reference. 417 * We also need to store the touched command line since the parameter 418 * parsing is performed in place, and we should allow a component to 419 * store reference of name/value for future reference. 420 */ 421 static void __init setup_command_line(char *command_line) 422 { 423 saved_command_line = alloc_bootmem(strlen (boot_command_line)+1); 424 static_command_line = alloc_bootmem(strlen (command_line)+1); 425 strcpy (saved_command_line, boot_command_line); 426 strcpy (static_command_line, command_line); 427 } 428 429 /* 430 * We need to finalize in a non-__init function or else race conditions 431 * between the root thread and the init thread may cause start_kernel to 432 * be reaped by free_initmem before the root thread has proceeded to 433 * cpu_idle. 434 * 435 * gcc-3.4 accidentally inlines this function, so use noinline. 436 */ 437 438 static void noinline __init_refok rest_init(void) 439 __releases(kernel_lock) 440 { 441 int pid; 442 443 kernel_thread(kernel_init, NULL, CLONE_FS | CLONE_SIGHAND); 444 numa_default_policy(); 445 pid = kernel_thread(kthreadd, NULL, CLONE_FS | CLONE_FILES); 446 kthreadd_task = find_task_by_pid(pid); 447 unlock_kernel(); 448 449 /* 450 * The boot idle thread must execute schedule() 451 * at least once to get things moving: 452 */ 453 init_idle_bootup_task(current); 454 preempt_enable_no_resched(); 455 schedule(); 456 preempt_disable(); 457 458 /* Call into cpu_idle with preempt disabled */ 459 cpu_idle(); 460 } 461 462 /* Check for early params. */ 463 static int __init do_early_param(char *param, char *val) 464 { 465 struct obs_kernel_param *p; 466 467 for (p = __setup_start; p < __setup_end; p++) { 468 if ((p->early && strcmp(param, p->str) == 0) || 469 (strcmp(param, "console") == 0 && 470 strcmp(p->str, "earlycon") == 0) 471 ) { 472 if (p->setup_func(val) != 0) 473 printk(KERN_WARNING 474 "Malformed early option '%s'\n", param); 475 } 476 } 477 /* We accept everything at this stage. */ 478 return 0; 479 } 480 481 /* Arch code calls this early on, or if not, just before other parsing. */ 482 void __init parse_early_param(void) 483 { 484 static __initdata int done = 0; 485 static __initdata char tmp_cmdline[COMMAND_LINE_SIZE]; 486 487 if (done) 488 return; 489 490 /* All fall through to do_early_param. */ 491 strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE); 492 parse_args("early options", tmp_cmdline, NULL, 0, do_early_param); 493 done = 1; 494 } 495 496 /* 497 * Activate the first processor. 498 */ 499 500 static void __init boot_cpu_init(void) 501 { 502 int cpu = smp_processor_id(); 503 /* Mark the boot cpu "present", "online" etc for SMP and UP case */ 504 cpu_set(cpu, cpu_online_map); 505 cpu_set(cpu, cpu_present_map); 506 cpu_set(cpu, cpu_possible_map); 507 } 508 509 void __init __attribute__((weak)) smp_setup_processor_id(void) 510 { 511 } 512 513 asmlinkage void __init start_kernel(void) 514 { 515 char * command_line; 516 extern struct kernel_param __start___param[], __stop___param[]; 517 518 smp_setup_processor_id(); 519 520 /* 521 * Need to run as early as possible, to initialize the 522 * lockdep hash: 523 */ 524 unwind_init(); 525 lockdep_init(); 526 cgroup_init_early(); 527 528 local_irq_disable(); 529 early_boot_irqs_off(); 530 early_init_irq_lock_class(); 531 532 /* 533 * Interrupts are still disabled. Do necessary setups, then 534 * enable them 535 */ 536 lock_kernel(); 537 tick_init(); 538 boot_cpu_init(); 539 page_address_init(); 540 printk(KERN_NOTICE); 541 printk(linux_banner); 542 setup_arch(&command_line); 543 setup_command_line(command_line); 544 unwind_setup(); 545 setup_per_cpu_areas(); 546 smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */ 547 548 /* 549 * Set up the scheduler prior starting any interrupts (such as the 550 * timer interrupt). Full topology setup happens at smp_init() 551 * time - but meanwhile we still have a functioning scheduler. 552 */ 553 sched_init(); 554 /* 555 * Disable preemption - early bootup scheduling is extremely 556 * fragile until we cpu_idle() for the first time. 557 */ 558 preempt_disable(); 559 build_all_zonelists(); 560 page_alloc_init(); 561 printk(KERN_NOTICE "Kernel command line: %s\n", boot_command_line); 562 parse_early_param(); 563 parse_args("Booting kernel", static_command_line, __start___param, 564 __stop___param - __start___param, 565 &unknown_bootoption); 566 if (!irqs_disabled()) { 567 printk(KERN_WARNING "start_kernel(): bug: interrupts were " 568 "enabled *very* early, fixing it\n"); 569 local_irq_disable(); 570 } 571 sort_main_extable(); 572 trap_init(); 573 rcu_init(); 574 init_IRQ(); 575 pidhash_init(); 576 init_timers(); 577 hrtimers_init(); 578 softirq_init(); 579 timekeeping_init(); 580 time_init(); 581 profile_init(); 582 if (!irqs_disabled()) 583 printk("start_kernel(): bug: interrupts were enabled early\n"); 584 early_boot_irqs_on(); 585 local_irq_enable(); 586 587 /* 588 * HACK ALERT! This is early. We're enabling the console before 589 * we've done PCI setups etc, and console_init() must be aware of 590 * this. But we do want output early, in case something goes wrong. 591 */ 592 console_init(); 593 if (panic_later) 594 panic(panic_later, panic_param); 595 596 lockdep_info(); 597 598 /* 599 * Need to run this when irqs are enabled, because it wants 600 * to self-test [hard/soft]-irqs on/off lock inversion bugs 601 * too: 602 */ 603 locking_selftest(); 604 605 #ifdef CONFIG_BLK_DEV_INITRD 606 if (initrd_start && !initrd_below_start_ok && 607 initrd_start < min_low_pfn << PAGE_SHIFT) { 608 printk(KERN_CRIT "initrd overwritten (0x%08lx < 0x%08lx) - " 609 "disabling it.\n",initrd_start,min_low_pfn << PAGE_SHIFT); 610 initrd_start = 0; 611 } 612 #endif 613 vfs_caches_init_early(); 614 cpuset_init_early(); 615 mem_init(); 616 enable_debug_pagealloc(); 617 cpu_hotplug_init(); 618 kmem_cache_init(); 619 setup_per_cpu_pageset(); 620 numa_policy_init(); 621 if (late_time_init) 622 late_time_init(); 623 calibrate_delay(); 624 pidmap_init(); 625 pgtable_cache_init(); 626 prio_tree_init(); 627 anon_vma_init(); 628 #ifdef CONFIG_X86 629 if (efi_enabled) 630 efi_enter_virtual_mode(); 631 #endif 632 fork_init(num_physpages); 633 proc_caches_init(); 634 buffer_init(); 635 unnamed_dev_init(); 636 key_init(); 637 security_init(); 638 vfs_caches_init(num_physpages); 639 radix_tree_init(); 640 signals_init(); 641 /* rootfs populating might need page-writeback */ 642 page_writeback_init(); 643 #ifdef CONFIG_PROC_FS 644 proc_root_init(); 645 #endif 646 cgroup_init(); 647 cpuset_init(); 648 taskstats_init_early(); 649 delayacct_init(); 650 651 check_bugs(); 652 653 populate_rootfs(); /* For DSDT override from initramfs */ 654 acpi_early_init(); /* before LAPIC and SMP init */ 655 656 /* Do the rest non-__init'ed, we're now alive */ 657 rest_init(); 658 } 659 660 static int __initdata initcall_debug; 661 662 static int __init initcall_debug_setup(char *str) 663 { 664 initcall_debug = 1; 665 return 1; 666 } 667 __setup("initcall_debug", initcall_debug_setup); 668 669 extern initcall_t __initcall_start[], __initcall_end[]; 670 671 static void __init do_initcalls(void) 672 { 673 initcall_t *call; 674 int count = preempt_count(); 675 676 for (call = __initcall_start; call < __initcall_end; call++) { 677 ktime_t t0, t1, delta; 678 char *msg = NULL; 679 char msgbuf[40]; 680 int result; 681 682 if (initcall_debug) { 683 printk("Calling initcall 0x%p", *call); 684 print_fn_descriptor_symbol(": %s()", 685 (unsigned long) *call); 686 printk("\n"); 687 t0 = ktime_get(); 688 } 689 690 result = (*call)(); 691 692 if (initcall_debug) { 693 t1 = ktime_get(); 694 delta = ktime_sub(t1, t0); 695 696 printk("initcall 0x%p", *call); 697 print_fn_descriptor_symbol(": %s()", 698 (unsigned long) *call); 699 printk(" returned %d.\n", result); 700 701 printk("initcall 0x%p ran for %Ld msecs: ", 702 *call, (unsigned long long)delta.tv64 >> 20); 703 print_fn_descriptor_symbol("%s()\n", 704 (unsigned long) *call); 705 } 706 707 if (result && result != -ENODEV && initcall_debug) { 708 sprintf(msgbuf, "error code %d", result); 709 msg = msgbuf; 710 } 711 if (preempt_count() != count) { 712 msg = "preemption imbalance"; 713 preempt_count() = count; 714 } 715 if (irqs_disabled()) { 716 msg = "disabled interrupts"; 717 local_irq_enable(); 718 } 719 if (msg) { 720 printk(KERN_WARNING "initcall at 0x%p", *call); 721 print_fn_descriptor_symbol(": %s()", 722 (unsigned long) *call); 723 printk(": returned with %s\n", msg); 724 } 725 } 726 727 /* Make sure there is no pending stuff from the initcall sequence */ 728 flush_scheduled_work(); 729 } 730 731 /* 732 * Ok, the machine is now initialized. None of the devices 733 * have been touched yet, but the CPU subsystem is up and 734 * running, and memory and process management works. 735 * 736 * Now we can finally start doing some real work.. 737 */ 738 static void __init do_basic_setup(void) 739 { 740 /* drivers will send hotplug events */ 741 init_workqueues(); 742 usermodehelper_init(); 743 driver_init(); 744 init_irq_proc(); 745 do_initcalls(); 746 } 747 748 static int __initdata nosoftlockup; 749 750 static int __init nosoftlockup_setup(char *str) 751 { 752 nosoftlockup = 1; 753 return 1; 754 } 755 __setup("nosoftlockup", nosoftlockup_setup); 756 757 static void __init do_pre_smp_initcalls(void) 758 { 759 extern int spawn_ksoftirqd(void); 760 761 migration_init(); 762 spawn_ksoftirqd(); 763 if (!nosoftlockup) 764 spawn_softlockup_task(); 765 } 766 767 static void run_init_process(char *init_filename) 768 { 769 argv_init[0] = init_filename; 770 kernel_execve(init_filename, argv_init, envp_init); 771 } 772 773 /* This is a non __init function. Force it to be noinline otherwise gcc 774 * makes it inline to init() and it becomes part of init.text section 775 */ 776 static int noinline init_post(void) 777 { 778 free_initmem(); 779 unlock_kernel(); 780 mark_rodata_ro(); 781 system_state = SYSTEM_RUNNING; 782 numa_default_policy(); 783 784 if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0) 785 printk(KERN_WARNING "Warning: unable to open an initial console.\n"); 786 787 (void) sys_dup(0); 788 (void) sys_dup(0); 789 790 if (ramdisk_execute_command) { 791 run_init_process(ramdisk_execute_command); 792 printk(KERN_WARNING "Failed to execute %s\n", 793 ramdisk_execute_command); 794 } 795 796 /* 797 * We try each of these until one succeeds. 798 * 799 * The Bourne shell can be used instead of init if we are 800 * trying to recover a really broken machine. 801 */ 802 if (execute_command) { 803 run_init_process(execute_command); 804 printk(KERN_WARNING "Failed to execute %s. Attempting " 805 "defaults...\n", execute_command); 806 } 807 run_init_process("/sbin/init"); 808 run_init_process("/etc/init"); 809 run_init_process("/bin/init"); 810 run_init_process("/bin/sh"); 811 812 panic("No init found. Try passing init= option to kernel."); 813 } 814 815 static int __init kernel_init(void * unused) 816 { 817 lock_kernel(); 818 /* 819 * init can run on any cpu. 820 */ 821 set_cpus_allowed(current, CPU_MASK_ALL); 822 /* 823 * Tell the world that we're going to be the grim 824 * reaper of innocent orphaned children. 825 * 826 * We don't want people to have to make incorrect 827 * assumptions about where in the task array this 828 * can be found. 829 */ 830 init_pid_ns.child_reaper = current; 831 832 cad_pid = task_pid(current); 833 834 smp_prepare_cpus(setup_max_cpus); 835 836 do_pre_smp_initcalls(); 837 838 smp_init(); 839 sched_init_smp(); 840 841 cpuset_init_smp(); 842 843 do_basic_setup(); 844 845 /* 846 * check if there is an early userspace init. If yes, let it do all 847 * the work 848 */ 849 850 if (!ramdisk_execute_command) 851 ramdisk_execute_command = "/init"; 852 853 if (sys_access((const char __user *) ramdisk_execute_command, 0) != 0) { 854 ramdisk_execute_command = NULL; 855 prepare_namespace(); 856 } 857 858 /* 859 * Ok, we have completed the initial bootup, and 860 * we're essentially up and running. Get rid of the 861 * initmem segments and start the user-mode stuff.. 862 */ 863 init_post(); 864 return 0; 865 } 866