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/bootmem.h> 26 #include <linux/tty.h> 27 #include <linux/gfp.h> 28 #include <linux/percpu.h> 29 #include <linux/kmod.h> 30 #include <linux/vmalloc.h> 31 #include <linux/kernel_stat.h> 32 #include <linux/start_kernel.h> 33 #include <linux/security.h> 34 #include <linux/smp.h> 35 #include <linux/workqueue.h> 36 #include <linux/profile.h> 37 #include <linux/rcupdate.h> 38 #include <linux/moduleparam.h> 39 #include <linux/kallsyms.h> 40 #include <linux/writeback.h> 41 #include <linux/cpu.h> 42 #include <linux/cpuset.h> 43 #include <linux/cgroup.h> 44 #include <linux/efi.h> 45 #include <linux/tick.h> 46 #include <linux/interrupt.h> 47 #include <linux/taskstats_kern.h> 48 #include <linux/delayacct.h> 49 #include <linux/unistd.h> 50 #include <linux/rmap.h> 51 #include <linux/mempolicy.h> 52 #include <linux/key.h> 53 #include <linux/buffer_head.h> 54 #include <linux/page_cgroup.h> 55 #include <linux/debug_locks.h> 56 #include <linux/debugobjects.h> 57 #include <linux/lockdep.h> 58 #include <linux/pid_namespace.h> 59 #include <linux/device.h> 60 #include <linux/kthread.h> 61 #include <linux/sched.h> 62 #include <linux/signal.h> 63 #include <linux/idr.h> 64 #include <linux/ftrace.h> 65 #include <trace/boot.h> 66 67 #include <asm/io.h> 68 #include <asm/bugs.h> 69 #include <asm/setup.h> 70 #include <asm/sections.h> 71 #include <asm/cacheflush.h> 72 73 #ifdef CONFIG_X86_LOCAL_APIC 74 #include <asm/smp.h> 75 #endif 76 77 static int kernel_init(void *); 78 79 extern void init_IRQ(void); 80 extern void fork_init(unsigned long); 81 extern void mca_init(void); 82 extern void sbus_init(void); 83 extern void prio_tree_init(void); 84 extern void radix_tree_init(void); 85 extern void free_initmem(void); 86 #ifdef CONFIG_ACPI 87 extern void acpi_early_init(void); 88 #else 89 static inline void acpi_early_init(void) { } 90 #endif 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 enum system_states system_state; 100 EXPORT_SYMBOL(system_state); 101 102 /* 103 * Boot command-line arguments 104 */ 105 #define MAX_INIT_ARGS CONFIG_INIT_ENV_ARG_LIMIT 106 #define MAX_INIT_ENVS CONFIG_INIT_ENV_ARG_LIMIT 107 108 extern void time_init(void); 109 /* Default late time init is NULL. archs can override this later. */ 110 void (*late_time_init)(void); 111 extern void softirq_init(void); 112 113 /* Untouched command line saved by arch-specific code. */ 114 char __initdata boot_command_line[COMMAND_LINE_SIZE]; 115 /* Untouched saved command line (eg. for /proc) */ 116 char *saved_command_line; 117 /* Command line for parameter parsing */ 118 static char *static_command_line; 119 120 static char *execute_command; 121 static char *ramdisk_execute_command; 122 123 #ifdef CONFIG_SMP 124 /* Setup configured maximum number of CPUs to activate */ 125 unsigned int __initdata setup_max_cpus = NR_CPUS; 126 127 /* 128 * Setup routine for controlling SMP activation 129 * 130 * Command-line option of "nosmp" or "maxcpus=0" will disable SMP 131 * activation entirely (the MPS table probe still happens, though). 132 * 133 * Command-line option of "maxcpus=<NUM>", where <NUM> is an integer 134 * greater than 0, limits the maximum number of CPUs activated in 135 * SMP mode to <NUM>. 136 */ 137 #ifndef CONFIG_X86_IO_APIC 138 static inline void disable_ioapic_setup(void) {}; 139 #endif 140 141 static int __init nosmp(char *str) 142 { 143 setup_max_cpus = 0; 144 disable_ioapic_setup(); 145 return 0; 146 } 147 148 early_param("nosmp", nosmp); 149 150 static int __init maxcpus(char *str) 151 { 152 get_option(&str, &setup_max_cpus); 153 if (setup_max_cpus == 0) 154 disable_ioapic_setup(); 155 156 return 0; 157 } 158 159 early_param("maxcpus", maxcpus); 160 #else 161 #define setup_max_cpus NR_CPUS 162 #endif 163 164 /* 165 * If set, this is an indication to the drivers that reset the underlying 166 * device before going ahead with the initialization otherwise driver might 167 * rely on the BIOS and skip the reset operation. 168 * 169 * This is useful if kernel is booting in an unreliable environment. 170 * For ex. kdump situaiton where previous kernel has crashed, BIOS has been 171 * skipped and devices will be in unknown state. 172 */ 173 unsigned int reset_devices; 174 EXPORT_SYMBOL(reset_devices); 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 console_loglevel = 10; 230 return 0; 231 } 232 233 static int __init quiet_kernel(char *str) 234 { 235 console_loglevel = 4; 236 return 0; 237 } 238 239 early_param("debug", debug_kernel); 240 early_param("quiet", quiet_kernel); 241 242 static int __init loglevel(char *str) 243 { 244 get_option(&str, &console_loglevel); 245 return 0; 246 } 247 248 early_param("loglevel", loglevel); 249 250 /* 251 * Unknown boot options get handed to init, unless they look like 252 * failed parameters 253 */ 254 static int __init unknown_bootoption(char *param, char *val) 255 { 256 /* Change NUL term back to "=", to make "param" the whole string. */ 257 if (val) { 258 /* param=val or param="val"? */ 259 if (val == param+strlen(param)+1) 260 val[-1] = '='; 261 else if (val == param+strlen(param)+2) { 262 val[-2] = '='; 263 memmove(val-1, val, strlen(val)+1); 264 val--; 265 } else 266 BUG(); 267 } 268 269 /* Handle obsolete-style parameters */ 270 if (obsolete_checksetup(param)) 271 return 0; 272 273 /* 274 * Preemptive maintenance for "why didn't my misspelled command 275 * line work?" 276 */ 277 if (strchr(param, '.') && (!val || strchr(param, '.') < val)) { 278 printk(KERN_ERR "Unknown boot option `%s': ignoring\n", param); 279 return 0; 280 } 281 282 if (panic_later) 283 return 0; 284 285 if (val) { 286 /* Environment option */ 287 unsigned int i; 288 for (i = 0; envp_init[i]; i++) { 289 if (i == MAX_INIT_ENVS) { 290 panic_later = "Too many boot env vars at `%s'"; 291 panic_param = param; 292 } 293 if (!strncmp(param, envp_init[i], val - param)) 294 break; 295 } 296 envp_init[i] = param; 297 } else { 298 /* Command line option */ 299 unsigned int i; 300 for (i = 0; argv_init[i]; i++) { 301 if (i == MAX_INIT_ARGS) { 302 panic_later = "Too many boot init vars at `%s'"; 303 panic_param = param; 304 } 305 } 306 argv_init[i] = param; 307 } 308 return 0; 309 } 310 311 #ifdef CONFIG_DEBUG_PAGEALLOC 312 int __read_mostly debug_pagealloc_enabled = 0; 313 #endif 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 setup_nr_cpu_ids(void) { } 357 static inline void smp_prepare_cpus(unsigned int maxcpus) { } 358 359 #else 360 361 #if NR_CPUS > BITS_PER_LONG 362 cpumask_t cpu_mask_all __read_mostly = CPU_MASK_ALL; 363 EXPORT_SYMBOL(cpu_mask_all); 364 #endif 365 366 /* Setup number of possible processor ids */ 367 int nr_cpu_ids __read_mostly = NR_CPUS; 368 EXPORT_SYMBOL(nr_cpu_ids); 369 370 /* An arch may set nr_cpu_ids earlier if needed, so this would be redundant */ 371 static void __init setup_nr_cpu_ids(void) 372 { 373 nr_cpu_ids = find_last_bit(cpumask_bits(cpu_possible_mask),NR_CPUS) + 1; 374 } 375 376 #ifndef CONFIG_HAVE_SETUP_PER_CPU_AREA 377 unsigned long __per_cpu_offset[NR_CPUS] __read_mostly; 378 379 EXPORT_SYMBOL(__per_cpu_offset); 380 381 static void __init setup_per_cpu_areas(void) 382 { 383 unsigned long size, i; 384 char *ptr; 385 unsigned long nr_possible_cpus = num_possible_cpus(); 386 387 /* Copy section for each CPU (we discard the original) */ 388 size = ALIGN(PERCPU_ENOUGH_ROOM, PAGE_SIZE); 389 ptr = alloc_bootmem_pages(size * nr_possible_cpus); 390 391 for_each_possible_cpu(i) { 392 __per_cpu_offset[i] = ptr - __per_cpu_start; 393 memcpy(ptr, __per_cpu_start, __per_cpu_end - __per_cpu_start); 394 ptr += size; 395 } 396 } 397 #endif /* CONFIG_HAVE_SETUP_PER_CPU_AREA */ 398 399 /* Called by boot processor to activate the rest. */ 400 static void __init smp_init(void) 401 { 402 unsigned int cpu; 403 404 /* 405 * Set up the current CPU as possible to migrate to. 406 * The other ones will be done by cpu_up/cpu_down() 407 */ 408 cpu = smp_processor_id(); 409 cpu_set(cpu, cpu_active_map); 410 411 /* FIXME: This should be done in userspace --RR */ 412 for_each_present_cpu(cpu) { 413 if (num_online_cpus() >= setup_max_cpus) 414 break; 415 if (!cpu_online(cpu)) 416 cpu_up(cpu); 417 } 418 419 /* Any cleanup work */ 420 printk(KERN_INFO "Brought up %ld CPUs\n", (long)num_online_cpus()); 421 smp_cpus_done(setup_max_cpus); 422 } 423 424 #endif 425 426 /* 427 * We need to store the untouched command line for future reference. 428 * We also need to store the touched command line since the parameter 429 * parsing is performed in place, and we should allow a component to 430 * store reference of name/value for future reference. 431 */ 432 static void __init setup_command_line(char *command_line) 433 { 434 saved_command_line = alloc_bootmem(strlen (boot_command_line)+1); 435 static_command_line = alloc_bootmem(strlen (command_line)+1); 436 strcpy (saved_command_line, boot_command_line); 437 strcpy (static_command_line, command_line); 438 } 439 440 /* 441 * We need to finalize in a non-__init function or else race conditions 442 * between the root thread and the init thread may cause start_kernel to 443 * be reaped by free_initmem before the root thread has proceeded to 444 * cpu_idle. 445 * 446 * gcc-3.4 accidentally inlines this function, so use noinline. 447 */ 448 449 static noinline void __init_refok rest_init(void) 450 __releases(kernel_lock) 451 { 452 int pid; 453 454 kernel_thread(kernel_init, NULL, CLONE_FS | CLONE_SIGHAND); 455 numa_default_policy(); 456 pid = kernel_thread(kthreadd, NULL, CLONE_FS | CLONE_FILES); 457 kthreadd_task = find_task_by_pid_ns(pid, &init_pid_ns); 458 unlock_kernel(); 459 460 /* 461 * The boot idle thread must execute schedule() 462 * at least once to get things moving: 463 */ 464 init_idle_bootup_task(current); 465 preempt_enable_no_resched(); 466 schedule(); 467 preempt_disable(); 468 469 /* Call into cpu_idle with preempt disabled */ 470 cpu_idle(); 471 } 472 473 /* Check for early params. */ 474 static int __init do_early_param(char *param, char *val) 475 { 476 struct obs_kernel_param *p; 477 478 for (p = __setup_start; p < __setup_end; p++) { 479 if ((p->early && strcmp(param, p->str) == 0) || 480 (strcmp(param, "console") == 0 && 481 strcmp(p->str, "earlycon") == 0) 482 ) { 483 if (p->setup_func(val) != 0) 484 printk(KERN_WARNING 485 "Malformed early option '%s'\n", param); 486 } 487 } 488 /* We accept everything at this stage. */ 489 return 0; 490 } 491 492 /* Arch code calls this early on, or if not, just before other parsing. */ 493 void __init parse_early_param(void) 494 { 495 static __initdata int done = 0; 496 static __initdata char tmp_cmdline[COMMAND_LINE_SIZE]; 497 498 if (done) 499 return; 500 501 /* All fall through to do_early_param. */ 502 strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE); 503 parse_args("early options", tmp_cmdline, NULL, 0, do_early_param); 504 done = 1; 505 } 506 507 /* 508 * Activate the first processor. 509 */ 510 511 static void __init boot_cpu_init(void) 512 { 513 int cpu = smp_processor_id(); 514 /* Mark the boot cpu "present", "online" etc for SMP and UP case */ 515 set_cpu_online(cpu, true); 516 set_cpu_present(cpu, true); 517 set_cpu_possible(cpu, true); 518 } 519 520 void __init __weak smp_setup_processor_id(void) 521 { 522 } 523 524 void __init __weak thread_info_cache_init(void) 525 { 526 } 527 528 asmlinkage void __init start_kernel(void) 529 { 530 char * command_line; 531 extern struct kernel_param __start___param[], __stop___param[]; 532 533 smp_setup_processor_id(); 534 535 /* 536 * Need to run as early as possible, to initialize the 537 * lockdep hash: 538 */ 539 lockdep_init(); 540 debug_objects_early_init(); 541 cgroup_init_early(); 542 543 local_irq_disable(); 544 early_boot_irqs_off(); 545 early_init_irq_lock_class(); 546 547 /* 548 * Interrupts are still disabled. Do necessary setups, then 549 * enable them 550 */ 551 lock_kernel(); 552 tick_init(); 553 boot_cpu_init(); 554 page_address_init(); 555 printk(KERN_NOTICE); 556 printk(linux_banner); 557 setup_arch(&command_line); 558 mm_init_owner(&init_mm, &init_task); 559 setup_command_line(command_line); 560 setup_per_cpu_areas(); 561 setup_nr_cpu_ids(); 562 smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */ 563 564 /* 565 * Set up the scheduler prior starting any interrupts (such as the 566 * timer interrupt). Full topology setup happens at smp_init() 567 * time - but meanwhile we still have a functioning scheduler. 568 */ 569 sched_init(); 570 /* 571 * Disable preemption - early bootup scheduling is extremely 572 * fragile until we cpu_idle() for the first time. 573 */ 574 preempt_disable(); 575 build_all_zonelists(); 576 page_alloc_init(); 577 printk(KERN_NOTICE "Kernel command line: %s\n", boot_command_line); 578 parse_early_param(); 579 parse_args("Booting kernel", static_command_line, __start___param, 580 __stop___param - __start___param, 581 &unknown_bootoption); 582 if (!irqs_disabled()) { 583 printk(KERN_WARNING "start_kernel(): bug: interrupts were " 584 "enabled *very* early, fixing it\n"); 585 local_irq_disable(); 586 } 587 sort_main_extable(); 588 trap_init(); 589 rcu_init(); 590 /* init some links before init_ISA_irqs() */ 591 early_irq_init(); 592 init_IRQ(); 593 pidhash_init(); 594 init_timers(); 595 hrtimers_init(); 596 softirq_init(); 597 timekeeping_init(); 598 time_init(); 599 sched_clock_init(); 600 profile_init(); 601 if (!irqs_disabled()) 602 printk("start_kernel(): bug: interrupts were enabled early\n"); 603 early_boot_irqs_on(); 604 local_irq_enable(); 605 606 /* 607 * HACK ALERT! This is early. We're enabling the console before 608 * we've done PCI setups etc, and console_init() must be aware of 609 * this. But we do want output early, in case something goes wrong. 610 */ 611 console_init(); 612 if (panic_later) 613 panic(panic_later, panic_param); 614 615 lockdep_info(); 616 617 /* 618 * Need to run this when irqs are enabled, because it wants 619 * to self-test [hard/soft]-irqs on/off lock inversion bugs 620 * too: 621 */ 622 locking_selftest(); 623 624 #ifdef CONFIG_BLK_DEV_INITRD 625 if (initrd_start && !initrd_below_start_ok && 626 page_to_pfn(virt_to_page((void *)initrd_start)) < min_low_pfn) { 627 printk(KERN_CRIT "initrd overwritten (0x%08lx < 0x%08lx) - " 628 "disabling it.\n", 629 page_to_pfn(virt_to_page((void *)initrd_start)), 630 min_low_pfn); 631 initrd_start = 0; 632 } 633 #endif 634 vmalloc_init(); 635 vfs_caches_init_early(); 636 cpuset_init_early(); 637 page_cgroup_init(); 638 mem_init(); 639 enable_debug_pagealloc(); 640 cpu_hotplug_init(); 641 kmem_cache_init(); 642 debug_objects_mem_init(); 643 idr_init_cache(); 644 setup_per_cpu_pageset(); 645 numa_policy_init(); 646 if (late_time_init) 647 late_time_init(); 648 calibrate_delay(); 649 pidmap_init(); 650 pgtable_cache_init(); 651 prio_tree_init(); 652 anon_vma_init(); 653 #ifdef CONFIG_X86 654 if (efi_enabled) 655 efi_enter_virtual_mode(); 656 #endif 657 thread_info_cache_init(); 658 cred_init(); 659 fork_init(num_physpages); 660 proc_caches_init(); 661 buffer_init(); 662 key_init(); 663 security_init(); 664 vfs_caches_init(num_physpages); 665 radix_tree_init(); 666 signals_init(); 667 /* rootfs populating might need page-writeback */ 668 page_writeback_init(); 669 #ifdef CONFIG_PROC_FS 670 proc_root_init(); 671 #endif 672 cgroup_init(); 673 cpuset_init(); 674 taskstats_init_early(); 675 delayacct_init(); 676 677 check_bugs(); 678 679 acpi_early_init(); /* before LAPIC and SMP init */ 680 681 ftrace_init(); 682 683 /* Do the rest non-__init'ed, we're now alive */ 684 rest_init(); 685 } 686 687 static int initcall_debug; 688 core_param(initcall_debug, initcall_debug, bool, 0644); 689 690 int do_one_initcall(initcall_t fn) 691 { 692 int count = preempt_count(); 693 ktime_t calltime, delta, rettime; 694 char msgbuf[64]; 695 struct boot_trace_call call; 696 struct boot_trace_ret ret; 697 698 if (initcall_debug) { 699 call.caller = task_pid_nr(current); 700 printk("calling %pF @ %i\n", fn, call.caller); 701 calltime = ktime_get(); 702 trace_boot_call(&call, fn); 703 enable_boot_trace(); 704 } 705 706 ret.result = fn(); 707 708 if (initcall_debug) { 709 disable_boot_trace(); 710 rettime = ktime_get(); 711 delta = ktime_sub(rettime, calltime); 712 ret.duration = (unsigned long long) ktime_to_ns(delta) >> 10; 713 trace_boot_ret(&ret, fn); 714 printk("initcall %pF returned %d after %Ld usecs\n", fn, 715 ret.result, ret.duration); 716 } 717 718 msgbuf[0] = 0; 719 720 if (ret.result && ret.result != -ENODEV && initcall_debug) 721 sprintf(msgbuf, "error code %d ", ret.result); 722 723 if (preempt_count() != count) { 724 strlcat(msgbuf, "preemption imbalance ", sizeof(msgbuf)); 725 preempt_count() = count; 726 } 727 if (irqs_disabled()) { 728 strlcat(msgbuf, "disabled interrupts ", sizeof(msgbuf)); 729 local_irq_enable(); 730 } 731 if (msgbuf[0]) { 732 printk("initcall %pF returned with %s\n", fn, msgbuf); 733 } 734 735 return ret.result; 736 } 737 738 739 extern initcall_t __initcall_start[], __initcall_end[], __early_initcall_end[]; 740 741 static void __init do_initcalls(void) 742 { 743 initcall_t *call; 744 745 for (call = __early_initcall_end; call < __initcall_end; call++) 746 do_one_initcall(*call); 747 748 /* Make sure there is no pending stuff from the initcall sequence */ 749 flush_scheduled_work(); 750 } 751 752 /* 753 * Ok, the machine is now initialized. None of the devices 754 * have been touched yet, but the CPU subsystem is up and 755 * running, and memory and process management works. 756 * 757 * Now we can finally start doing some real work.. 758 */ 759 static void __init do_basic_setup(void) 760 { 761 rcu_init_sched(); /* needed by module_init stage. */ 762 init_workqueues(); 763 usermodehelper_init(); 764 driver_init(); 765 init_irq_proc(); 766 do_initcalls(); 767 } 768 769 static void __init do_pre_smp_initcalls(void) 770 { 771 initcall_t *call; 772 773 for (call = __initcall_start; call < __early_initcall_end; call++) 774 do_one_initcall(*call); 775 } 776 777 static void run_init_process(char *init_filename) 778 { 779 argv_init[0] = init_filename; 780 kernel_execve(init_filename, argv_init, envp_init); 781 } 782 783 /* This is a non __init function. Force it to be noinline otherwise gcc 784 * makes it inline to init() and it becomes part of init.text section 785 */ 786 static noinline int init_post(void) 787 { 788 free_initmem(); 789 unlock_kernel(); 790 mark_rodata_ro(); 791 system_state = SYSTEM_RUNNING; 792 numa_default_policy(); 793 794 if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0) 795 printk(KERN_WARNING "Warning: unable to open an initial console.\n"); 796 797 (void) sys_dup(0); 798 (void) sys_dup(0); 799 800 current->signal->flags |= SIGNAL_UNKILLABLE; 801 802 if (ramdisk_execute_command) { 803 run_init_process(ramdisk_execute_command); 804 printk(KERN_WARNING "Failed to execute %s\n", 805 ramdisk_execute_command); 806 } 807 808 /* 809 * We try each of these until one succeeds. 810 * 811 * The Bourne shell can be used instead of init if we are 812 * trying to recover a really broken machine. 813 */ 814 if (execute_command) { 815 run_init_process(execute_command); 816 printk(KERN_WARNING "Failed to execute %s. Attempting " 817 "defaults...\n", execute_command); 818 } 819 run_init_process("/sbin/init"); 820 run_init_process("/etc/init"); 821 run_init_process("/bin/init"); 822 run_init_process("/bin/sh"); 823 824 panic("No init found. Try passing init= option to kernel."); 825 } 826 827 static int __init kernel_init(void * unused) 828 { 829 lock_kernel(); 830 /* 831 * init can run on any cpu. 832 */ 833 set_cpus_allowed_ptr(current, CPU_MASK_ALL_PTR); 834 /* 835 * Tell the world that we're going to be the grim 836 * reaper of innocent orphaned children. 837 * 838 * We don't want people to have to make incorrect 839 * assumptions about where in the task array this 840 * can be found. 841 */ 842 init_pid_ns.child_reaper = current; 843 844 cad_pid = task_pid(current); 845 846 smp_prepare_cpus(setup_max_cpus); 847 848 do_pre_smp_initcalls(); 849 start_boot_trace(); 850 851 smp_init(); 852 sched_init_smp(); 853 854 cpuset_init_smp(); 855 856 do_basic_setup(); 857 858 /* 859 * check if there is an early userspace init. If yes, let it do all 860 * the work 861 */ 862 863 if (!ramdisk_execute_command) 864 ramdisk_execute_command = "/init"; 865 866 if (sys_access((const char __user *) ramdisk_execute_command, 0) != 0) { 867 ramdisk_execute_command = NULL; 868 prepare_namespace(); 869 } 870 871 /* 872 * Ok, we have completed the initial bootup, and 873 * we're essentially up and running. Get rid of the 874 * initmem segments and start the user-mode stuff.. 875 */ 876 877 init_post(); 878 return 0; 879 } 880