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/smp_lock.h> 24 #include <linux/initrd.h> 25 #include <linux/bootmem.h> 26 #include <linux/acpi.h> 27 #include <linux/tty.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/kmemleak.h> 59 #include <linux/pid_namespace.h> 60 #include <linux/device.h> 61 #include <linux/kthread.h> 62 #include <linux/sched.h> 63 #include <linux/signal.h> 64 #include <linux/idr.h> 65 #include <linux/kgdb.h> 66 #include <linux/ftrace.h> 67 #include <linux/async.h> 68 #include <linux/kmemcheck.h> 69 #include <linux/kmemtrace.h> 70 #include <linux/sfi.h> 71 #include <linux/shmem_fs.h> 72 #include <linux/slab.h> 73 #include <trace/boot.h> 74 75 #include <asm/io.h> 76 #include <asm/bugs.h> 77 #include <asm/setup.h> 78 #include <asm/sections.h> 79 #include <asm/cacheflush.h> 80 81 #ifdef CONFIG_X86_LOCAL_APIC 82 #include <asm/smp.h> 83 #endif 84 85 static int kernel_init(void *); 86 87 extern void init_IRQ(void); 88 extern void fork_init(unsigned long); 89 extern void mca_init(void); 90 extern void sbus_init(void); 91 extern void prio_tree_init(void); 92 extern void radix_tree_init(void); 93 extern void free_initmem(void); 94 #ifndef CONFIG_DEBUG_RODATA 95 static inline void mark_rodata_ro(void) { } 96 #endif 97 98 #ifdef CONFIG_TC 99 extern void tc_init(void); 100 #endif 101 102 enum system_states system_state __read_mostly; 103 EXPORT_SYMBOL(system_state); 104 105 /* 106 * Boot command-line arguments 107 */ 108 #define MAX_INIT_ARGS CONFIG_INIT_ENV_ARG_LIMIT 109 #define MAX_INIT_ENVS CONFIG_INIT_ENV_ARG_LIMIT 110 111 extern void time_init(void); 112 /* Default late time init is NULL. archs can override this later. */ 113 void (*__initdata late_time_init)(void); 114 extern void softirq_init(void); 115 116 /* Untouched command line saved by arch-specific code. */ 117 char __initdata boot_command_line[COMMAND_LINE_SIZE]; 118 /* Untouched saved command line (eg. for /proc) */ 119 char *saved_command_line; 120 /* Command line for parameter parsing */ 121 static char *static_command_line; 122 123 static char *execute_command; 124 static char *ramdisk_execute_command; 125 126 #ifdef CONFIG_SMP 127 /* Setup configured maximum number of CPUs to activate */ 128 unsigned int setup_max_cpus = NR_CPUS; 129 EXPORT_SYMBOL(setup_max_cpus); 130 131 132 /* 133 * Setup routine for controlling SMP activation 134 * 135 * Command-line option of "nosmp" or "maxcpus=0" will disable SMP 136 * activation entirely (the MPS table probe still happens, though). 137 * 138 * Command-line option of "maxcpus=<NUM>", where <NUM> is an integer 139 * greater than 0, limits the maximum number of CPUs activated in 140 * SMP mode to <NUM>. 141 */ 142 143 void __weak arch_disable_smp_support(void) { } 144 145 static int __init nosmp(char *str) 146 { 147 setup_max_cpus = 0; 148 arch_disable_smp_support(); 149 150 return 0; 151 } 152 153 early_param("nosmp", nosmp); 154 155 /* this is hard limit */ 156 static int __init nrcpus(char *str) 157 { 158 int nr_cpus; 159 160 get_option(&str, &nr_cpus); 161 if (nr_cpus > 0 && nr_cpus < nr_cpu_ids) 162 nr_cpu_ids = nr_cpus; 163 164 return 0; 165 } 166 167 early_param("nr_cpus", nrcpus); 168 169 static int __init maxcpus(char *str) 170 { 171 get_option(&str, &setup_max_cpus); 172 if (setup_max_cpus == 0) 173 arch_disable_smp_support(); 174 175 return 0; 176 } 177 178 early_param("maxcpus", maxcpus); 179 #else 180 static const unsigned int setup_max_cpus = NR_CPUS; 181 #endif 182 183 /* 184 * If set, this is an indication to the drivers that reset the underlying 185 * device before going ahead with the initialization otherwise driver might 186 * rely on the BIOS and skip the reset operation. 187 * 188 * This is useful if kernel is booting in an unreliable environment. 189 * For ex. kdump situaiton where previous kernel has crashed, BIOS has been 190 * skipped and devices will be in unknown state. 191 */ 192 unsigned int reset_devices; 193 EXPORT_SYMBOL(reset_devices); 194 195 static int __init set_reset_devices(char *str) 196 { 197 reset_devices = 1; 198 return 1; 199 } 200 201 __setup("reset_devices", set_reset_devices); 202 203 static char * argv_init[MAX_INIT_ARGS+2] = { "init", NULL, }; 204 char * envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, }; 205 static const char *panic_later, *panic_param; 206 207 extern struct obs_kernel_param __setup_start[], __setup_end[]; 208 209 static int __init obsolete_checksetup(char *line) 210 { 211 struct obs_kernel_param *p; 212 int had_early_param = 0; 213 214 p = __setup_start; 215 do { 216 int n = strlen(p->str); 217 if (!strncmp(line, p->str, n)) { 218 if (p->early) { 219 /* Already done in parse_early_param? 220 * (Needs exact match on param part). 221 * Keep iterating, as we can have early 222 * params and __setups of same names 8( */ 223 if (line[n] == '\0' || line[n] == '=') 224 had_early_param = 1; 225 } else if (!p->setup_func) { 226 printk(KERN_WARNING "Parameter %s is obsolete," 227 " ignored\n", p->str); 228 return 1; 229 } else if (p->setup_func(line + n)) 230 return 1; 231 } 232 p++; 233 } while (p < __setup_end); 234 235 return had_early_param; 236 } 237 238 /* 239 * This should be approx 2 Bo*oMips to start (note initial shift), and will 240 * still work even if initially too large, it will just take slightly longer 241 */ 242 unsigned long loops_per_jiffy = (1<<12); 243 244 EXPORT_SYMBOL(loops_per_jiffy); 245 246 static int __init debug_kernel(char *str) 247 { 248 console_loglevel = 10; 249 return 0; 250 } 251 252 static int __init quiet_kernel(char *str) 253 { 254 console_loglevel = 4; 255 return 0; 256 } 257 258 early_param("debug", debug_kernel); 259 early_param("quiet", quiet_kernel); 260 261 static int __init loglevel(char *str) 262 { 263 get_option(&str, &console_loglevel); 264 return 0; 265 } 266 267 early_param("loglevel", loglevel); 268 269 /* 270 * Unknown boot options get handed to init, unless they look like 271 * unused parameters (modprobe will find them in /proc/cmdline). 272 */ 273 static int __init unknown_bootoption(char *param, char *val) 274 { 275 /* Change NUL term back to "=", to make "param" the whole string. */ 276 if (val) { 277 /* param=val or param="val"? */ 278 if (val == param+strlen(param)+1) 279 val[-1] = '='; 280 else if (val == param+strlen(param)+2) { 281 val[-2] = '='; 282 memmove(val-1, val, strlen(val)+1); 283 val--; 284 } else 285 BUG(); 286 } 287 288 /* Handle obsolete-style parameters */ 289 if (obsolete_checksetup(param)) 290 return 0; 291 292 /* Unused module parameter. */ 293 if (strchr(param, '.') && (!val || strchr(param, '.') < val)) 294 return 0; 295 296 if (panic_later) 297 return 0; 298 299 if (val) { 300 /* Environment option */ 301 unsigned int i; 302 for (i = 0; envp_init[i]; i++) { 303 if (i == MAX_INIT_ENVS) { 304 panic_later = "Too many boot env vars at `%s'"; 305 panic_param = param; 306 } 307 if (!strncmp(param, envp_init[i], val - param)) 308 break; 309 } 310 envp_init[i] = param; 311 } else { 312 /* Command line option */ 313 unsigned int i; 314 for (i = 0; argv_init[i]; i++) { 315 if (i == MAX_INIT_ARGS) { 316 panic_later = "Too many boot init vars at `%s'"; 317 panic_param = param; 318 } 319 } 320 argv_init[i] = param; 321 } 322 return 0; 323 } 324 325 #ifdef CONFIG_DEBUG_PAGEALLOC 326 int __read_mostly debug_pagealloc_enabled = 0; 327 #endif 328 329 static int __init init_setup(char *str) 330 { 331 unsigned int i; 332 333 execute_command = str; 334 /* 335 * In case LILO is going to boot us with default command line, 336 * it prepends "auto" before the whole cmdline which makes 337 * the shell think it should execute a script with such name. 338 * So we ignore all arguments entered _before_ init=... [MJ] 339 */ 340 for (i = 1; i < MAX_INIT_ARGS; i++) 341 argv_init[i] = NULL; 342 return 1; 343 } 344 __setup("init=", init_setup); 345 346 static int __init rdinit_setup(char *str) 347 { 348 unsigned int i; 349 350 ramdisk_execute_command = str; 351 /* See "auto" comment in init_setup */ 352 for (i = 1; i < MAX_INIT_ARGS; i++) 353 argv_init[i] = NULL; 354 return 1; 355 } 356 __setup("rdinit=", rdinit_setup); 357 358 #ifndef CONFIG_SMP 359 360 #ifdef CONFIG_X86_LOCAL_APIC 361 static void __init smp_init(void) 362 { 363 APIC_init_uniprocessor(); 364 } 365 #else 366 #define smp_init() do { } while (0) 367 #endif 368 369 static inline void setup_nr_cpu_ids(void) { } 370 static inline void smp_prepare_cpus(unsigned int maxcpus) { } 371 372 #else 373 374 /* Setup number of possible processor ids */ 375 int nr_cpu_ids __read_mostly = NR_CPUS; 376 EXPORT_SYMBOL(nr_cpu_ids); 377 378 /* An arch may set nr_cpu_ids earlier if needed, so this would be redundant */ 379 static void __init setup_nr_cpu_ids(void) 380 { 381 nr_cpu_ids = find_last_bit(cpumask_bits(cpu_possible_mask),NR_CPUS) + 1; 382 } 383 384 /* Called by boot processor to activate the rest. */ 385 static void __init smp_init(void) 386 { 387 unsigned int cpu; 388 389 /* FIXME: This should be done in userspace --RR */ 390 for_each_present_cpu(cpu) { 391 if (num_online_cpus() >= setup_max_cpus) 392 break; 393 if (!cpu_online(cpu)) 394 cpu_up(cpu); 395 } 396 397 /* Any cleanup work */ 398 printk(KERN_INFO "Brought up %ld CPUs\n", (long)num_online_cpus()); 399 smp_cpus_done(setup_max_cpus); 400 } 401 402 #endif 403 404 /* 405 * We need to store the untouched command line for future reference. 406 * We also need to store the touched command line since the parameter 407 * parsing is performed in place, and we should allow a component to 408 * store reference of name/value for future reference. 409 */ 410 static void __init setup_command_line(char *command_line) 411 { 412 saved_command_line = alloc_bootmem(strlen (boot_command_line)+1); 413 static_command_line = alloc_bootmem(strlen (command_line)+1); 414 strcpy (saved_command_line, boot_command_line); 415 strcpy (static_command_line, command_line); 416 } 417 418 /* 419 * We need to finalize in a non-__init function or else race conditions 420 * between the root thread and the init thread may cause start_kernel to 421 * be reaped by free_initmem before the root thread has proceeded to 422 * cpu_idle. 423 * 424 * gcc-3.4 accidentally inlines this function, so use noinline. 425 */ 426 427 static noinline void __init_refok rest_init(void) 428 __releases(kernel_lock) 429 { 430 int pid; 431 432 rcu_scheduler_starting(); 433 kernel_thread(kernel_init, NULL, CLONE_FS | CLONE_SIGHAND); 434 numa_default_policy(); 435 pid = kernel_thread(kthreadd, NULL, CLONE_FS | CLONE_FILES); 436 rcu_read_lock(); 437 kthreadd_task = find_task_by_pid_ns(pid, &init_pid_ns); 438 rcu_read_unlock(); 439 unlock_kernel(); 440 441 /* 442 * The boot idle thread must execute schedule() 443 * at least once to get things moving: 444 */ 445 init_idle_bootup_task(current); 446 preempt_enable_no_resched(); 447 schedule(); 448 preempt_disable(); 449 450 /* Call into cpu_idle with preempt disabled */ 451 cpu_idle(); 452 } 453 454 /* Check for early params. */ 455 static int __init do_early_param(char *param, char *val) 456 { 457 struct obs_kernel_param *p; 458 459 for (p = __setup_start; p < __setup_end; p++) { 460 if ((p->early && strcmp(param, p->str) == 0) || 461 (strcmp(param, "console") == 0 && 462 strcmp(p->str, "earlycon") == 0) 463 ) { 464 if (p->setup_func(val) != 0) 465 printk(KERN_WARNING 466 "Malformed early option '%s'\n", param); 467 } 468 } 469 /* We accept everything at this stage. */ 470 return 0; 471 } 472 473 void __init parse_early_options(char *cmdline) 474 { 475 parse_args("early options", cmdline, NULL, 0, do_early_param); 476 } 477 478 /* Arch code calls this early on, or if not, just before other parsing. */ 479 void __init parse_early_param(void) 480 { 481 static __initdata int done = 0; 482 static __initdata char tmp_cmdline[COMMAND_LINE_SIZE]; 483 484 if (done) 485 return; 486 487 /* All fall through to do_early_param. */ 488 strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE); 489 parse_early_options(tmp_cmdline); 490 done = 1; 491 } 492 493 /* 494 * Activate the first processor. 495 */ 496 497 static void __init boot_cpu_init(void) 498 { 499 int cpu = smp_processor_id(); 500 /* Mark the boot cpu "present", "online" etc for SMP and UP case */ 501 set_cpu_online(cpu, true); 502 set_cpu_active(cpu, true); 503 set_cpu_present(cpu, true); 504 set_cpu_possible(cpu, true); 505 } 506 507 void __init __weak smp_setup_processor_id(void) 508 { 509 } 510 511 void __init __weak thread_info_cache_init(void) 512 { 513 } 514 515 /* 516 * Set up kernel memory allocators 517 */ 518 static void __init mm_init(void) 519 { 520 /* 521 * page_cgroup requires countinous pages as memmap 522 * and it's bigger than MAX_ORDER unless SPARSEMEM. 523 */ 524 page_cgroup_init_flatmem(); 525 mem_init(); 526 kmem_cache_init(); 527 pgtable_cache_init(); 528 vmalloc_init(); 529 } 530 531 asmlinkage void __init start_kernel(void) 532 { 533 char * command_line; 534 extern struct kernel_param __start___param[], __stop___param[]; 535 536 smp_setup_processor_id(); 537 538 /* 539 * Need to run as early as possible, to initialize the 540 * lockdep hash: 541 */ 542 lockdep_init(); 543 debug_objects_early_init(); 544 545 /* 546 * Set up the the initial canary ASAP: 547 */ 548 boot_init_stack_canary(); 549 550 cgroup_init_early(); 551 552 local_irq_disable(); 553 early_boot_irqs_off(); 554 early_init_irq_lock_class(); 555 556 /* 557 * Interrupts are still disabled. Do necessary setups, then 558 * enable them 559 */ 560 lock_kernel(); 561 tick_init(); 562 boot_cpu_init(); 563 page_address_init(); 564 printk(KERN_NOTICE "%s", linux_banner); 565 setup_arch(&command_line); 566 mm_init_owner(&init_mm, &init_task); 567 setup_command_line(command_line); 568 setup_nr_cpu_ids(); 569 setup_per_cpu_areas(); 570 smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */ 571 572 build_all_zonelists(NULL); 573 page_alloc_init(); 574 575 printk(KERN_NOTICE "Kernel command line: %s\n", boot_command_line); 576 parse_early_param(); 577 parse_args("Booting kernel", static_command_line, __start___param, 578 __stop___param - __start___param, 579 &unknown_bootoption); 580 /* 581 * These use large bootmem allocations and must precede 582 * kmem_cache_init() 583 */ 584 pidhash_init(); 585 vfs_caches_init_early(); 586 sort_main_extable(); 587 trap_init(); 588 mm_init(); 589 /* 590 * Set up the scheduler prior starting any interrupts (such as the 591 * timer interrupt). Full topology setup happens at smp_init() 592 * time - but meanwhile we still have a functioning scheduler. 593 */ 594 sched_init(); 595 /* 596 * Disable preemption - early bootup scheduling is extremely 597 * fragile until we cpu_idle() for the first time. 598 */ 599 preempt_disable(); 600 if (!irqs_disabled()) { 601 printk(KERN_WARNING "start_kernel(): bug: interrupts were " 602 "enabled *very* early, fixing it\n"); 603 local_irq_disable(); 604 } 605 rcu_init(); 606 radix_tree_init(); 607 /* init some links before init_ISA_irqs() */ 608 early_irq_init(); 609 init_IRQ(); 610 prio_tree_init(); 611 init_timers(); 612 hrtimers_init(); 613 softirq_init(); 614 timekeeping_init(); 615 time_init(); 616 profile_init(); 617 if (!irqs_disabled()) 618 printk(KERN_CRIT "start_kernel(): bug: interrupts were " 619 "enabled early\n"); 620 early_boot_irqs_on(); 621 local_irq_enable(); 622 623 /* Interrupts are enabled now so all GFP allocations are safe. */ 624 gfp_allowed_mask = __GFP_BITS_MASK; 625 626 kmem_cache_init_late(); 627 628 /* 629 * HACK ALERT! This is early. We're enabling the console before 630 * we've done PCI setups etc, and console_init() must be aware of 631 * this. But we do want output early, in case something goes wrong. 632 */ 633 console_init(); 634 if (panic_later) 635 panic(panic_later, panic_param); 636 637 lockdep_info(); 638 639 /* 640 * Need to run this when irqs are enabled, because it wants 641 * to self-test [hard/soft]-irqs on/off lock inversion bugs 642 * too: 643 */ 644 locking_selftest(); 645 646 #ifdef CONFIG_BLK_DEV_INITRD 647 if (initrd_start && !initrd_below_start_ok && 648 page_to_pfn(virt_to_page((void *)initrd_start)) < min_low_pfn) { 649 printk(KERN_CRIT "initrd overwritten (0x%08lx < 0x%08lx) - " 650 "disabling it.\n", 651 page_to_pfn(virt_to_page((void *)initrd_start)), 652 min_low_pfn); 653 initrd_start = 0; 654 } 655 #endif 656 page_cgroup_init(); 657 enable_debug_pagealloc(); 658 kmemtrace_init(); 659 kmemleak_init(); 660 debug_objects_mem_init(); 661 idr_init_cache(); 662 setup_per_cpu_pageset(); 663 numa_policy_init(); 664 if (late_time_init) 665 late_time_init(); 666 sched_clock_init(); 667 calibrate_delay(); 668 pidmap_init(); 669 anon_vma_init(); 670 #ifdef CONFIG_X86 671 if (efi_enabled) 672 efi_enter_virtual_mode(); 673 #endif 674 thread_info_cache_init(); 675 cred_init(); 676 fork_init(totalram_pages); 677 proc_caches_init(); 678 buffer_init(); 679 key_init(); 680 security_init(); 681 dbg_late_init(); 682 vfs_caches_init(totalram_pages); 683 signals_init(); 684 /* rootfs populating might need page-writeback */ 685 page_writeback_init(); 686 #ifdef CONFIG_PROC_FS 687 proc_root_init(); 688 #endif 689 cgroup_init(); 690 cpuset_init(); 691 taskstats_init_early(); 692 delayacct_init(); 693 694 check_bugs(); 695 696 acpi_early_init(); /* before LAPIC and SMP init */ 697 sfi_init_late(); 698 699 ftrace_init(); 700 701 /* Do the rest non-__init'ed, we're now alive */ 702 rest_init(); 703 } 704 705 /* Call all constructor functions linked into the kernel. */ 706 static void __init do_ctors(void) 707 { 708 #ifdef CONFIG_CONSTRUCTORS 709 ctor_fn_t *fn = (ctor_fn_t *) __ctors_start; 710 711 for (; fn < (ctor_fn_t *) __ctors_end; fn++) 712 (*fn)(); 713 #endif 714 } 715 716 int initcall_debug; 717 core_param(initcall_debug, initcall_debug, bool, 0644); 718 719 static char msgbuf[64]; 720 static struct boot_trace_call call; 721 static struct boot_trace_ret ret; 722 723 int do_one_initcall(initcall_t fn) 724 { 725 int count = preempt_count(); 726 ktime_t calltime, delta, rettime; 727 728 if (initcall_debug) { 729 call.caller = task_pid_nr(current); 730 printk("calling %pF @ %i\n", fn, call.caller); 731 calltime = ktime_get(); 732 trace_boot_call(&call, fn); 733 enable_boot_trace(); 734 } 735 736 ret.result = fn(); 737 738 if (initcall_debug) { 739 disable_boot_trace(); 740 rettime = ktime_get(); 741 delta = ktime_sub(rettime, calltime); 742 ret.duration = (unsigned long long) ktime_to_ns(delta) >> 10; 743 trace_boot_ret(&ret, fn); 744 printk("initcall %pF returned %d after %Ld usecs\n", fn, 745 ret.result, ret.duration); 746 } 747 748 msgbuf[0] = 0; 749 750 if (ret.result && ret.result != -ENODEV && initcall_debug) 751 sprintf(msgbuf, "error code %d ", ret.result); 752 753 if (preempt_count() != count) { 754 strlcat(msgbuf, "preemption imbalance ", sizeof(msgbuf)); 755 preempt_count() = count; 756 } 757 if (irqs_disabled()) { 758 strlcat(msgbuf, "disabled interrupts ", sizeof(msgbuf)); 759 local_irq_enable(); 760 } 761 if (msgbuf[0]) { 762 printk("initcall %pF returned with %s\n", fn, msgbuf); 763 } 764 765 return ret.result; 766 } 767 768 769 extern initcall_t __initcall_start[], __initcall_end[], __early_initcall_end[]; 770 771 static void __init do_initcalls(void) 772 { 773 initcall_t *fn; 774 775 for (fn = __early_initcall_end; fn < __initcall_end; fn++) 776 do_one_initcall(*fn); 777 778 /* Make sure there is no pending stuff from the initcall sequence */ 779 flush_scheduled_work(); 780 } 781 782 /* 783 * Ok, the machine is now initialized. None of the devices 784 * have been touched yet, but the CPU subsystem is up and 785 * running, and memory and process management works. 786 * 787 * Now we can finally start doing some real work.. 788 */ 789 static void __init do_basic_setup(void) 790 { 791 init_workqueues(); 792 cpuset_init_smp(); 793 usermodehelper_init(); 794 init_tmpfs(); 795 driver_init(); 796 init_irq_proc(); 797 do_ctors(); 798 do_initcalls(); 799 } 800 801 static void __init do_pre_smp_initcalls(void) 802 { 803 initcall_t *fn; 804 805 for (fn = __initcall_start; fn < __early_initcall_end; fn++) 806 do_one_initcall(*fn); 807 } 808 809 static void run_init_process(char *init_filename) 810 { 811 argv_init[0] = init_filename; 812 kernel_execve(init_filename, argv_init, envp_init); 813 } 814 815 /* This is a non __init function. Force it to be noinline otherwise gcc 816 * makes it inline to init() and it becomes part of init.text section 817 */ 818 static noinline int init_post(void) 819 __releases(kernel_lock) 820 { 821 /* need to finish all async __init code before freeing the memory */ 822 async_synchronize_full(); 823 free_initmem(); 824 unlock_kernel(); 825 mark_rodata_ro(); 826 system_state = SYSTEM_RUNNING; 827 numa_default_policy(); 828 829 830 current->signal->flags |= SIGNAL_UNKILLABLE; 831 832 if (ramdisk_execute_command) { 833 run_init_process(ramdisk_execute_command); 834 printk(KERN_WARNING "Failed to execute %s\n", 835 ramdisk_execute_command); 836 } 837 838 /* 839 * We try each of these until one succeeds. 840 * 841 * The Bourne shell can be used instead of init if we are 842 * trying to recover a really broken machine. 843 */ 844 if (execute_command) { 845 run_init_process(execute_command); 846 printk(KERN_WARNING "Failed to execute %s. Attempting " 847 "defaults...\n", execute_command); 848 } 849 run_init_process("/sbin/init"); 850 run_init_process("/etc/init"); 851 run_init_process("/bin/init"); 852 run_init_process("/bin/sh"); 853 854 panic("No init found. Try passing init= option to kernel. " 855 "See Linux Documentation/init.txt for guidance."); 856 } 857 858 static int __init kernel_init(void * unused) 859 { 860 lock_kernel(); 861 862 /* 863 * init can allocate pages on any node 864 */ 865 set_mems_allowed(node_states[N_HIGH_MEMORY]); 866 /* 867 * init can run on any cpu. 868 */ 869 set_cpus_allowed_ptr(current, cpu_all_mask); 870 /* 871 * Tell the world that we're going to be the grim 872 * reaper of innocent orphaned children. 873 * 874 * We don't want people to have to make incorrect 875 * assumptions about where in the task array this 876 * can be found. 877 */ 878 init_pid_ns.child_reaper = current; 879 880 cad_pid = task_pid(current); 881 882 smp_prepare_cpus(setup_max_cpus); 883 884 do_pre_smp_initcalls(); 885 start_boot_trace(); 886 887 smp_init(); 888 sched_init_smp(); 889 890 do_basic_setup(); 891 892 /* Open the /dev/console on the rootfs, this should never fail */ 893 if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0) 894 printk(KERN_WARNING "Warning: unable to open an initial console.\n"); 895 896 (void) sys_dup(0); 897 (void) sys_dup(0); 898 /* 899 * check if there is an early userspace init. If yes, let it do all 900 * the work 901 */ 902 903 if (!ramdisk_execute_command) 904 ramdisk_execute_command = "/init"; 905 906 if (sys_access((const char __user *) ramdisk_execute_command, 0) != 0) { 907 ramdisk_execute_command = NULL; 908 prepare_namespace(); 909 } 910 911 /* 912 * Ok, we have completed the initial bootup, and 913 * we're essentially up and running. Get rid of the 914 * initmem segments and start the user-mode stuff.. 915 */ 916 917 init_post(); 918 return 0; 919 } 920