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 (!strncmp(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 #ifdef CONFIG_DEBUG_PAGEALLOC 286 int __read_mostly debug_pagealloc_enabled = 0; 287 #endif 288 289 static int __init init_setup(char *str) 290 { 291 unsigned int i; 292 293 execute_command = str; 294 /* 295 * In case LILO is going to boot us with default command line, 296 * it prepends "auto" before the whole cmdline which makes 297 * the shell think it should execute a script with such name. 298 * So we ignore all arguments entered _before_ init=... [MJ] 299 */ 300 for (i = 1; i < MAX_INIT_ARGS; i++) 301 argv_init[i] = NULL; 302 return 1; 303 } 304 __setup("init=", init_setup); 305 306 static int __init rdinit_setup(char *str) 307 { 308 unsigned int i; 309 310 ramdisk_execute_command = str; 311 /* See "auto" comment in init_setup */ 312 for (i = 1; i < MAX_INIT_ARGS; i++) 313 argv_init[i] = NULL; 314 return 1; 315 } 316 __setup("rdinit=", rdinit_setup); 317 318 #ifndef CONFIG_SMP 319 static const unsigned int setup_max_cpus = NR_CPUS; 320 #ifdef CONFIG_X86_LOCAL_APIC 321 static void __init smp_init(void) 322 { 323 APIC_init_uniprocessor(); 324 } 325 #else 326 #define smp_init() do { } while (0) 327 #endif 328 329 static inline void setup_nr_cpu_ids(void) { } 330 static inline void smp_prepare_cpus(unsigned int maxcpus) { } 331 #endif 332 333 /* 334 * We need to store the untouched command line for future reference. 335 * We also need to store the touched command line since the parameter 336 * parsing is performed in place, and we should allow a component to 337 * store reference of name/value for future reference. 338 */ 339 static void __init setup_command_line(char *command_line) 340 { 341 saved_command_line = alloc_bootmem(strlen (boot_command_line)+1); 342 static_command_line = alloc_bootmem(strlen (command_line)+1); 343 strcpy (saved_command_line, boot_command_line); 344 strcpy (static_command_line, command_line); 345 } 346 347 /* 348 * We need to finalize in a non-__init function or else race conditions 349 * between the root thread and the init thread may cause start_kernel to 350 * be reaped by free_initmem before the root thread has proceeded to 351 * cpu_idle. 352 * 353 * gcc-3.4 accidentally inlines this function, so use noinline. 354 */ 355 356 static __initdata DECLARE_COMPLETION(kthreadd_done); 357 358 static noinline void __init_refok rest_init(void) 359 { 360 int pid; 361 362 rcu_scheduler_starting(); 363 /* 364 * We need to spawn init first so that it obtains pid 1, however 365 * the init task will end up wanting to create kthreads, which, if 366 * we schedule it before we create kthreadd, will OOPS. 367 */ 368 kernel_thread(kernel_init, NULL, CLONE_FS | CLONE_SIGHAND); 369 numa_default_policy(); 370 pid = kernel_thread(kthreadd, NULL, CLONE_FS | CLONE_FILES); 371 rcu_read_lock(); 372 kthreadd_task = find_task_by_pid_ns(pid, &init_pid_ns); 373 rcu_read_unlock(); 374 complete(&kthreadd_done); 375 376 /* 377 * The boot idle thread must execute schedule() 378 * at least once to get things moving: 379 */ 380 init_idle_bootup_task(current); 381 preempt_enable_no_resched(); 382 schedule(); 383 384 /* Call into cpu_idle with preempt disabled */ 385 preempt_disable(); 386 cpu_idle(); 387 } 388 389 /* Check for early params. */ 390 static int __init do_early_param(char *param, char *val) 391 { 392 const struct obs_kernel_param *p; 393 394 for (p = __setup_start; p < __setup_end; p++) { 395 if ((p->early && strcmp(param, p->str) == 0) || 396 (strcmp(param, "console") == 0 && 397 strcmp(p->str, "earlycon") == 0) 398 ) { 399 if (p->setup_func(val) != 0) 400 printk(KERN_WARNING 401 "Malformed early option '%s'\n", param); 402 } 403 } 404 /* We accept everything at this stage. */ 405 return 0; 406 } 407 408 void __init parse_early_options(char *cmdline) 409 { 410 parse_args("early options", cmdline, NULL, 0, do_early_param); 411 } 412 413 /* Arch code calls this early on, or if not, just before other parsing. */ 414 void __init parse_early_param(void) 415 { 416 static __initdata int done = 0; 417 static __initdata char tmp_cmdline[COMMAND_LINE_SIZE]; 418 419 if (done) 420 return; 421 422 /* All fall through to do_early_param. */ 423 strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE); 424 parse_early_options(tmp_cmdline); 425 done = 1; 426 } 427 428 /* 429 * Activate the first processor. 430 */ 431 432 static void __init boot_cpu_init(void) 433 { 434 int cpu = smp_processor_id(); 435 /* Mark the boot cpu "present", "online" etc for SMP and UP case */ 436 set_cpu_online(cpu, true); 437 set_cpu_active(cpu, true); 438 set_cpu_present(cpu, true); 439 set_cpu_possible(cpu, true); 440 } 441 442 void __init __weak smp_setup_processor_id(void) 443 { 444 } 445 446 void __init __weak thread_info_cache_init(void) 447 { 448 } 449 450 /* 451 * Set up kernel memory allocators 452 */ 453 static void __init mm_init(void) 454 { 455 /* 456 * page_cgroup requires countinous pages as memmap 457 * and it's bigger than MAX_ORDER unless SPARSEMEM. 458 */ 459 page_cgroup_init_flatmem(); 460 mem_init(); 461 kmem_cache_init(); 462 percpu_init_late(); 463 pgtable_cache_init(); 464 vmalloc_init(); 465 } 466 467 asmlinkage void __init start_kernel(void) 468 { 469 char * command_line; 470 extern const struct kernel_param __start___param[], __stop___param[]; 471 472 smp_setup_processor_id(); 473 474 /* 475 * Need to run as early as possible, to initialize the 476 * lockdep hash: 477 */ 478 lockdep_init(); 479 debug_objects_early_init(); 480 481 /* 482 * Set up the the initial canary ASAP: 483 */ 484 boot_init_stack_canary(); 485 486 cgroup_init_early(); 487 488 local_irq_disable(); 489 early_boot_irqs_disabled = true; 490 491 /* 492 * Interrupts are still disabled. Do necessary setups, then 493 * enable them 494 */ 495 tick_init(); 496 boot_cpu_init(); 497 page_address_init(); 498 printk(KERN_NOTICE "%s", linux_banner); 499 setup_arch(&command_line); 500 mm_init_owner(&init_mm, &init_task); 501 mm_init_cpumask(&init_mm); 502 setup_command_line(command_line); 503 setup_nr_cpu_ids(); 504 setup_per_cpu_areas(); 505 smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */ 506 507 build_all_zonelists(NULL); 508 page_alloc_init(); 509 510 printk(KERN_NOTICE "Kernel command line: %s\n", boot_command_line); 511 parse_early_param(); 512 parse_args("Booting kernel", static_command_line, __start___param, 513 __stop___param - __start___param, 514 &unknown_bootoption); 515 /* 516 * These use large bootmem allocations and must precede 517 * kmem_cache_init() 518 */ 519 setup_log_buf(0); 520 pidhash_init(); 521 vfs_caches_init_early(); 522 sort_main_extable(); 523 trap_init(); 524 mm_init(); 525 526 /* 527 * Set up the scheduler prior starting any interrupts (such as the 528 * timer interrupt). Full topology setup happens at smp_init() 529 * time - but meanwhile we still have a functioning scheduler. 530 */ 531 sched_init(); 532 /* 533 * Disable preemption - early bootup scheduling is extremely 534 * fragile until we cpu_idle() for the first time. 535 */ 536 preempt_disable(); 537 if (!irqs_disabled()) { 538 printk(KERN_WARNING "start_kernel(): bug: interrupts were " 539 "enabled *very* early, fixing it\n"); 540 local_irq_disable(); 541 } 542 idr_init_cache(); 543 perf_event_init(); 544 rcu_init(); 545 radix_tree_init(); 546 /* init some links before init_ISA_irqs() */ 547 early_irq_init(); 548 init_IRQ(); 549 prio_tree_init(); 550 init_timers(); 551 hrtimers_init(); 552 softirq_init(); 553 timekeeping_init(); 554 time_init(); 555 profile_init(); 556 call_function_init(); 557 if (!irqs_disabled()) 558 printk(KERN_CRIT "start_kernel(): bug: interrupts were " 559 "enabled early\n"); 560 early_boot_irqs_disabled = false; 561 local_irq_enable(); 562 563 /* Interrupts are enabled now so all GFP allocations are safe. */ 564 gfp_allowed_mask = __GFP_BITS_MASK; 565 566 kmem_cache_init_late(); 567 568 /* 569 * HACK ALERT! This is early. We're enabling the console before 570 * we've done PCI setups etc, and console_init() must be aware of 571 * this. But we do want output early, in case something goes wrong. 572 */ 573 console_init(); 574 if (panic_later) 575 panic(panic_later, panic_param); 576 577 lockdep_info(); 578 579 /* 580 * Need to run this when irqs are enabled, because it wants 581 * to self-test [hard/soft]-irqs on/off lock inversion bugs 582 * too: 583 */ 584 locking_selftest(); 585 586 #ifdef CONFIG_BLK_DEV_INITRD 587 if (initrd_start && !initrd_below_start_ok && 588 page_to_pfn(virt_to_page((void *)initrd_start)) < min_low_pfn) { 589 printk(KERN_CRIT "initrd overwritten (0x%08lx < 0x%08lx) - " 590 "disabling it.\n", 591 page_to_pfn(virt_to_page((void *)initrd_start)), 592 min_low_pfn); 593 initrd_start = 0; 594 } 595 #endif 596 page_cgroup_init(); 597 enable_debug_pagealloc(); 598 debug_objects_mem_init(); 599 kmemleak_init(); 600 setup_per_cpu_pageset(); 601 numa_policy_init(); 602 if (late_time_init) 603 late_time_init(); 604 sched_clock_init(); 605 calibrate_delay(); 606 pidmap_init(); 607 anon_vma_init(); 608 #ifdef CONFIG_X86 609 if (efi_enabled) 610 efi_enter_virtual_mode(); 611 #endif 612 thread_info_cache_init(); 613 cred_init(); 614 fork_init(totalram_pages); 615 proc_caches_init(); 616 buffer_init(); 617 key_init(); 618 security_init(); 619 dbg_late_init(); 620 vfs_caches_init(totalram_pages); 621 signals_init(); 622 /* rootfs populating might need page-writeback */ 623 page_writeback_init(); 624 #ifdef CONFIG_PROC_FS 625 proc_root_init(); 626 #endif 627 cgroup_init(); 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 sfi_init_late(); 636 637 ftrace_init(); 638 639 /* Do the rest non-__init'ed, we're now alive */ 640 rest_init(); 641 } 642 643 /* Call all constructor functions linked into the kernel. */ 644 static void __init do_ctors(void) 645 { 646 #ifdef CONFIG_CONSTRUCTORS 647 ctor_fn_t *fn = (ctor_fn_t *) __ctors_start; 648 649 for (; fn < (ctor_fn_t *) __ctors_end; fn++) 650 (*fn)(); 651 #endif 652 } 653 654 int initcall_debug; 655 core_param(initcall_debug, initcall_debug, bool, 0644); 656 657 static char msgbuf[64]; 658 659 static int __init_or_module do_one_initcall_debug(initcall_t fn) 660 { 661 ktime_t calltime, delta, rettime; 662 unsigned long long duration; 663 int ret; 664 665 printk(KERN_DEBUG "calling %pF @ %i\n", fn, task_pid_nr(current)); 666 calltime = ktime_get(); 667 ret = fn(); 668 rettime = ktime_get(); 669 delta = ktime_sub(rettime, calltime); 670 duration = (unsigned long long) ktime_to_ns(delta) >> 10; 671 printk(KERN_DEBUG "initcall %pF returned %d after %lld usecs\n", fn, 672 ret, duration); 673 674 return ret; 675 } 676 677 int __init_or_module do_one_initcall(initcall_t fn) 678 { 679 int count = preempt_count(); 680 int ret; 681 682 if (initcall_debug) 683 ret = do_one_initcall_debug(fn); 684 else 685 ret = fn(); 686 687 msgbuf[0] = 0; 688 689 if (ret && ret != -ENODEV && initcall_debug) 690 sprintf(msgbuf, "error code %d ", ret); 691 692 if (preempt_count() != count) { 693 strlcat(msgbuf, "preemption imbalance ", sizeof(msgbuf)); 694 preempt_count() = count; 695 } 696 if (irqs_disabled()) { 697 strlcat(msgbuf, "disabled interrupts ", sizeof(msgbuf)); 698 local_irq_enable(); 699 } 700 if (msgbuf[0]) { 701 printk("initcall %pF returned with %s\n", fn, msgbuf); 702 } 703 704 return ret; 705 } 706 707 708 extern initcall_t __initcall_start[], __initcall_end[], __early_initcall_end[]; 709 710 static void __init do_initcalls(void) 711 { 712 initcall_t *fn; 713 714 for (fn = __early_initcall_end; fn < __initcall_end; fn++) 715 do_one_initcall(*fn); 716 } 717 718 /* 719 * Ok, the machine is now initialized. None of the devices 720 * have been touched yet, but the CPU subsystem is up and 721 * running, and memory and process management works. 722 * 723 * Now we can finally start doing some real work.. 724 */ 725 static void __init do_basic_setup(void) 726 { 727 cpuset_init_smp(); 728 usermodehelper_init(); 729 shmem_init(); 730 driver_init(); 731 init_irq_proc(); 732 do_ctors(); 733 usermodehelper_enable(); 734 do_initcalls(); 735 } 736 737 static void __init do_pre_smp_initcalls(void) 738 { 739 initcall_t *fn; 740 741 for (fn = __initcall_start; fn < __early_initcall_end; fn++) 742 do_one_initcall(*fn); 743 } 744 745 static void run_init_process(const char *init_filename) 746 { 747 argv_init[0] = init_filename; 748 kernel_execve(init_filename, argv_init, envp_init); 749 } 750 751 /* This is a non __init function. Force it to be noinline otherwise gcc 752 * makes it inline to init() and it becomes part of init.text section 753 */ 754 static noinline int init_post(void) 755 { 756 /* need to finish all async __init code before freeing the memory */ 757 async_synchronize_full(); 758 free_initmem(); 759 mark_rodata_ro(); 760 system_state = SYSTEM_RUNNING; 761 numa_default_policy(); 762 763 764 current->signal->flags |= SIGNAL_UNKILLABLE; 765 766 if (ramdisk_execute_command) { 767 run_init_process(ramdisk_execute_command); 768 printk(KERN_WARNING "Failed to execute %s\n", 769 ramdisk_execute_command); 770 } 771 772 /* 773 * We try each of these until one succeeds. 774 * 775 * The Bourne shell can be used instead of init if we are 776 * trying to recover a really broken machine. 777 */ 778 if (execute_command) { 779 run_init_process(execute_command); 780 printk(KERN_WARNING "Failed to execute %s. Attempting " 781 "defaults...\n", execute_command); 782 } 783 run_init_process("/sbin/init"); 784 run_init_process("/etc/init"); 785 run_init_process("/bin/init"); 786 run_init_process("/bin/sh"); 787 788 panic("No init found. Try passing init= option to kernel. " 789 "See Linux Documentation/init.txt for guidance."); 790 } 791 792 static int __init kernel_init(void * unused) 793 { 794 /* 795 * Wait until kthreadd is all set-up. 796 */ 797 wait_for_completion(&kthreadd_done); 798 /* 799 * init can allocate pages on any node 800 */ 801 set_mems_allowed(node_states[N_HIGH_MEMORY]); 802 /* 803 * init can run on any cpu. 804 */ 805 set_cpus_allowed_ptr(current, cpu_all_mask); 806 807 cad_pid = task_pid(current); 808 809 smp_prepare_cpus(setup_max_cpus); 810 811 do_pre_smp_initcalls(); 812 lockup_detector_init(); 813 814 smp_init(); 815 sched_init_smp(); 816 817 do_basic_setup(); 818 819 /* Open the /dev/console on the rootfs, this should never fail */ 820 if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0) 821 printk(KERN_WARNING "Warning: unable to open an initial console.\n"); 822 823 (void) sys_dup(0); 824 (void) sys_dup(0); 825 /* 826 * check if there is an early userspace init. If yes, let it do all 827 * the work 828 */ 829 830 if (!ramdisk_execute_command) 831 ramdisk_execute_command = "/init"; 832 833 if (sys_access((const char __user *) ramdisk_execute_command, 0) != 0) { 834 ramdisk_execute_command = NULL; 835 prepare_namespace(); 836 } 837 838 /* 839 * Ok, we have completed the initial bootup, and 840 * we're essentially up and running. Get rid of the 841 * initmem segments and start the user-mode stuff.. 842 */ 843 844 init_post(); 845 return 0; 846 } 847