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/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/buffer_head.h> 53 #include <linux/page_cgroup.h> 54 #include <linux/debug_locks.h> 55 #include <linux/debugobjects.h> 56 #include <linux/lockdep.h> 57 #include <linux/kmemleak.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/kgdb.h> 65 #include <linux/ftrace.h> 66 #include <linux/async.h> 67 #include <linux/kmemcheck.h> 68 #include <linux/sfi.h> 69 #include <linux/shmem_fs.h> 70 #include <linux/slab.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 enum system_states system_state __read_mostly; 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 (*__initdata 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 setup_max_cpus = NR_CPUS; 126 EXPORT_SYMBOL(setup_max_cpus); 127 128 129 /* 130 * Setup routine for controlling SMP activation 131 * 132 * Command-line option of "nosmp" or "maxcpus=0" will disable SMP 133 * activation entirely (the MPS table probe still happens, though). 134 * 135 * Command-line option of "maxcpus=<NUM>", where <NUM> is an integer 136 * greater than 0, limits the maximum number of CPUs activated in 137 * SMP mode to <NUM>. 138 */ 139 140 void __weak arch_disable_smp_support(void) { } 141 142 static int __init nosmp(char *str) 143 { 144 setup_max_cpus = 0; 145 arch_disable_smp_support(); 146 147 return 0; 148 } 149 150 early_param("nosmp", nosmp); 151 152 /* this is hard limit */ 153 static int __init nrcpus(char *str) 154 { 155 int nr_cpus; 156 157 get_option(&str, &nr_cpus); 158 if (nr_cpus > 0 && nr_cpus < nr_cpu_ids) 159 nr_cpu_ids = nr_cpus; 160 161 return 0; 162 } 163 164 early_param("nr_cpus", nrcpus); 165 166 static int __init maxcpus(char *str) 167 { 168 get_option(&str, &setup_max_cpus); 169 if (setup_max_cpus == 0) 170 arch_disable_smp_support(); 171 172 return 0; 173 } 174 175 early_param("maxcpus", maxcpus); 176 #else 177 static const unsigned int setup_max_cpus = NR_CPUS; 178 #endif 179 180 /* 181 * If set, this is an indication to the drivers that reset the underlying 182 * device before going ahead with the initialization otherwise driver might 183 * rely on the BIOS and skip the reset operation. 184 * 185 * This is useful if kernel is booting in an unreliable environment. 186 * For ex. kdump situaiton where previous kernel has crashed, BIOS has been 187 * skipped and devices will be in unknown state. 188 */ 189 unsigned int reset_devices; 190 EXPORT_SYMBOL(reset_devices); 191 192 static int __init set_reset_devices(char *str) 193 { 194 reset_devices = 1; 195 return 1; 196 } 197 198 __setup("reset_devices", set_reset_devices); 199 200 static const char * argv_init[MAX_INIT_ARGS+2] = { "init", NULL, }; 201 const char * envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, }; 202 static const char *panic_later, *panic_param; 203 204 extern const struct obs_kernel_param __setup_start[], __setup_end[]; 205 206 static int __init obsolete_checksetup(char *line) 207 { 208 const struct obs_kernel_param *p; 209 int had_early_param = 0; 210 211 p = __setup_start; 212 do { 213 int n = strlen(p->str); 214 if (!strncmp(line, p->str, n)) { 215 if (p->early) { 216 /* Already done in parse_early_param? 217 * (Needs exact match on param part). 218 * Keep iterating, as we can have early 219 * params and __setups of same names 8( */ 220 if (line[n] == '\0' || line[n] == '=') 221 had_early_param = 1; 222 } else if (!p->setup_func) { 223 printk(KERN_WARNING "Parameter %s is obsolete," 224 " ignored\n", p->str); 225 return 1; 226 } else if (p->setup_func(line + n)) 227 return 1; 228 } 229 p++; 230 } while (p < __setup_end); 231 232 return had_early_param; 233 } 234 235 /* 236 * This should be approx 2 Bo*oMips to start (note initial shift), and will 237 * still work even if initially too large, it will just take slightly longer 238 */ 239 unsigned long loops_per_jiffy = (1<<12); 240 241 EXPORT_SYMBOL(loops_per_jiffy); 242 243 static int __init debug_kernel(char *str) 244 { 245 console_loglevel = 10; 246 return 0; 247 } 248 249 static int __init quiet_kernel(char *str) 250 { 251 console_loglevel = 4; 252 return 0; 253 } 254 255 early_param("debug", debug_kernel); 256 early_param("quiet", quiet_kernel); 257 258 static int __init loglevel(char *str) 259 { 260 get_option(&str, &console_loglevel); 261 return 0; 262 } 263 264 early_param("loglevel", loglevel); 265 266 /* 267 * Unknown boot options get handed to init, unless they look like 268 * unused parameters (modprobe will find them in /proc/cmdline). 269 */ 270 static int __init unknown_bootoption(char *param, char *val) 271 { 272 /* Change NUL term back to "=", to make "param" the whole string. */ 273 if (val) { 274 /* param=val or param="val"? */ 275 if (val == param+strlen(param)+1) 276 val[-1] = '='; 277 else if (val == param+strlen(param)+2) { 278 val[-2] = '='; 279 memmove(val-1, val, strlen(val)+1); 280 val--; 281 } else 282 BUG(); 283 } 284 285 /* Handle obsolete-style parameters */ 286 if (obsolete_checksetup(param)) 287 return 0; 288 289 /* Unused module parameter. */ 290 if (strchr(param, '.') && (!val || strchr(param, '.') < val)) 291 return 0; 292 293 if (panic_later) 294 return 0; 295 296 if (val) { 297 /* Environment option */ 298 unsigned int i; 299 for (i = 0; envp_init[i]; i++) { 300 if (i == MAX_INIT_ENVS) { 301 panic_later = "Too many boot env vars at `%s'"; 302 panic_param = param; 303 } 304 if (!strncmp(param, envp_init[i], val - param)) 305 break; 306 } 307 envp_init[i] = param; 308 } else { 309 /* Command line option */ 310 unsigned int i; 311 for (i = 0; argv_init[i]; i++) { 312 if (i == MAX_INIT_ARGS) { 313 panic_later = "Too many boot init vars at `%s'"; 314 panic_param = param; 315 } 316 } 317 argv_init[i] = param; 318 } 319 return 0; 320 } 321 322 #ifdef CONFIG_DEBUG_PAGEALLOC 323 int __read_mostly debug_pagealloc_enabled = 0; 324 #endif 325 326 static int __init init_setup(char *str) 327 { 328 unsigned int i; 329 330 execute_command = str; 331 /* 332 * In case LILO is going to boot us with default command line, 333 * it prepends "auto" before the whole cmdline which makes 334 * the shell think it should execute a script with such name. 335 * So we ignore all arguments entered _before_ init=... [MJ] 336 */ 337 for (i = 1; i < MAX_INIT_ARGS; i++) 338 argv_init[i] = NULL; 339 return 1; 340 } 341 __setup("init=", init_setup); 342 343 static int __init rdinit_setup(char *str) 344 { 345 unsigned int i; 346 347 ramdisk_execute_command = str; 348 /* See "auto" comment in init_setup */ 349 for (i = 1; i < MAX_INIT_ARGS; i++) 350 argv_init[i] = NULL; 351 return 1; 352 } 353 __setup("rdinit=", rdinit_setup); 354 355 #ifndef CONFIG_SMP 356 357 #ifdef CONFIG_X86_LOCAL_APIC 358 static void __init smp_init(void) 359 { 360 APIC_init_uniprocessor(); 361 } 362 #else 363 #define smp_init() do { } while (0) 364 #endif 365 366 static inline void setup_nr_cpu_ids(void) { } 367 static inline void smp_prepare_cpus(unsigned int maxcpus) { } 368 369 #else 370 371 /* Setup number of possible processor ids */ 372 int nr_cpu_ids __read_mostly = NR_CPUS; 373 EXPORT_SYMBOL(nr_cpu_ids); 374 375 /* An arch may set nr_cpu_ids earlier if needed, so this would be redundant */ 376 static void __init setup_nr_cpu_ids(void) 377 { 378 nr_cpu_ids = find_last_bit(cpumask_bits(cpu_possible_mask),NR_CPUS) + 1; 379 } 380 381 /* Called by boot processor to activate the rest. */ 382 static void __init smp_init(void) 383 { 384 unsigned int cpu; 385 386 /* FIXME: This should be done in userspace --RR */ 387 for_each_present_cpu(cpu) { 388 if (num_online_cpus() >= setup_max_cpus) 389 break; 390 if (!cpu_online(cpu)) 391 cpu_up(cpu); 392 } 393 394 /* Any cleanup work */ 395 printk(KERN_INFO "Brought up %ld CPUs\n", (long)num_online_cpus()); 396 smp_cpus_done(setup_max_cpus); 397 } 398 399 #endif 400 401 /* 402 * We need to store the untouched command line for future reference. 403 * We also need to store the touched command line since the parameter 404 * parsing is performed in place, and we should allow a component to 405 * store reference of name/value for future reference. 406 */ 407 static void __init setup_command_line(char *command_line) 408 { 409 saved_command_line = alloc_bootmem(strlen (boot_command_line)+1); 410 static_command_line = alloc_bootmem(strlen (command_line)+1); 411 strcpy (saved_command_line, boot_command_line); 412 strcpy (static_command_line, command_line); 413 } 414 415 /* 416 * We need to finalize in a non-__init function or else race conditions 417 * between the root thread and the init thread may cause start_kernel to 418 * be reaped by free_initmem before the root thread has proceeded to 419 * cpu_idle. 420 * 421 * gcc-3.4 accidentally inlines this function, so use noinline. 422 */ 423 424 static __initdata DECLARE_COMPLETION(kthreadd_done); 425 426 static noinline void __init_refok rest_init(void) 427 { 428 int pid; 429 430 rcu_scheduler_starting(); 431 /* 432 * We need to spawn init first so that it obtains pid 1, however 433 * the init task will end up wanting to create kthreads, which, if 434 * we schedule it before we create kthreadd, will OOPS. 435 */ 436 kernel_thread(kernel_init, NULL, CLONE_FS | CLONE_SIGHAND); 437 numa_default_policy(); 438 pid = kernel_thread(kthreadd, NULL, CLONE_FS | CLONE_FILES); 439 rcu_read_lock(); 440 kthreadd_task = find_task_by_pid_ns(pid, &init_pid_ns); 441 rcu_read_unlock(); 442 complete(&kthreadd_done); 443 444 /* 445 * The boot idle thread must execute schedule() 446 * at least once to get things moving: 447 */ 448 init_idle_bootup_task(current); 449 preempt_enable_no_resched(); 450 schedule(); 451 preempt_disable(); 452 453 /* Call into cpu_idle with preempt disabled */ 454 cpu_idle(); 455 } 456 457 /* Check for early params. */ 458 static int __init do_early_param(char *param, char *val) 459 { 460 const struct obs_kernel_param *p; 461 462 for (p = __setup_start; p < __setup_end; p++) { 463 if ((p->early && strcmp(param, p->str) == 0) || 464 (strcmp(param, "console") == 0 && 465 strcmp(p->str, "earlycon") == 0) 466 ) { 467 if (p->setup_func(val) != 0) 468 printk(KERN_WARNING 469 "Malformed early option '%s'\n", param); 470 } 471 } 472 /* We accept everything at this stage. */ 473 return 0; 474 } 475 476 void __init parse_early_options(char *cmdline) 477 { 478 parse_args("early options", cmdline, NULL, 0, do_early_param); 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_early_options(tmp_cmdline); 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 set_cpu_online(cpu, true); 505 set_cpu_active(cpu, true); 506 set_cpu_present(cpu, true); 507 set_cpu_possible(cpu, true); 508 } 509 510 void __init __weak smp_setup_processor_id(void) 511 { 512 } 513 514 void __init __weak thread_info_cache_init(void) 515 { 516 } 517 518 /* 519 * Set up kernel memory allocators 520 */ 521 static void __init mm_init(void) 522 { 523 /* 524 * page_cgroup requires countinous pages as memmap 525 * and it's bigger than MAX_ORDER unless SPARSEMEM. 526 */ 527 page_cgroup_init_flatmem(); 528 mem_init(); 529 kmem_cache_init(); 530 percpu_init_late(); 531 pgtable_cache_init(); 532 vmalloc_init(); 533 } 534 535 asmlinkage void __init start_kernel(void) 536 { 537 char * command_line; 538 extern const struct kernel_param __start___param[], __stop___param[]; 539 540 smp_setup_processor_id(); 541 542 /* 543 * Need to run as early as possible, to initialize the 544 * lockdep hash: 545 */ 546 lockdep_init(); 547 debug_objects_early_init(); 548 549 /* 550 * Set up the the initial canary ASAP: 551 */ 552 boot_init_stack_canary(); 553 554 cgroup_init_early(); 555 556 local_irq_disable(); 557 early_boot_irqs_off(); 558 559 /* 560 * Interrupts are still disabled. Do necessary setups, then 561 * enable them 562 */ 563 tick_init(); 564 boot_cpu_init(); 565 page_address_init(); 566 printk(KERN_NOTICE "%s", linux_banner); 567 setup_arch(&command_line); 568 mm_init_owner(&init_mm, &init_task); 569 setup_command_line(command_line); 570 setup_nr_cpu_ids(); 571 setup_per_cpu_areas(); 572 smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */ 573 574 build_all_zonelists(NULL); 575 page_alloc_init(); 576 577 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 /* 583 * These use large bootmem allocations and must precede 584 * kmem_cache_init() 585 */ 586 pidhash_init(); 587 vfs_caches_init_early(); 588 sort_main_extable(); 589 trap_init(); 590 mm_init(); 591 /* 592 * Set up the scheduler prior starting any interrupts (such as the 593 * timer interrupt). Full topology setup happens at smp_init() 594 * time - but meanwhile we still have a functioning scheduler. 595 */ 596 sched_init(); 597 /* 598 * Disable preemption - early bootup scheduling is extremely 599 * fragile until we cpu_idle() for the first time. 600 */ 601 preempt_disable(); 602 if (!irqs_disabled()) { 603 printk(KERN_WARNING "start_kernel(): bug: interrupts were " 604 "enabled *very* early, fixing it\n"); 605 local_irq_disable(); 606 } 607 rcu_init(); 608 radix_tree_init(); 609 /* init some links before init_ISA_irqs() */ 610 early_irq_init(); 611 init_IRQ(); 612 prio_tree_init(); 613 init_timers(); 614 hrtimers_init(); 615 softirq_init(); 616 timekeeping_init(); 617 time_init(); 618 profile_init(); 619 if (!irqs_disabled()) 620 printk(KERN_CRIT "start_kernel(): bug: interrupts were " 621 "enabled early\n"); 622 early_boot_irqs_on(); 623 local_irq_enable(); 624 625 /* Interrupts are enabled now so all GFP allocations are safe. */ 626 gfp_allowed_mask = __GFP_BITS_MASK; 627 628 kmem_cache_init_late(); 629 630 /* 631 * HACK ALERT! This is early. We're enabling the console before 632 * we've done PCI setups etc, and console_init() must be aware of 633 * this. But we do want output early, in case something goes wrong. 634 */ 635 console_init(); 636 if (panic_later) 637 panic(panic_later, panic_param); 638 639 lockdep_info(); 640 641 /* 642 * Need to run this when irqs are enabled, because it wants 643 * to self-test [hard/soft]-irqs on/off lock inversion bugs 644 * too: 645 */ 646 locking_selftest(); 647 648 #ifdef CONFIG_BLK_DEV_INITRD 649 if (initrd_start && !initrd_below_start_ok && 650 page_to_pfn(virt_to_page((void *)initrd_start)) < min_low_pfn) { 651 printk(KERN_CRIT "initrd overwritten (0x%08lx < 0x%08lx) - " 652 "disabling it.\n", 653 page_to_pfn(virt_to_page((void *)initrd_start)), 654 min_low_pfn); 655 initrd_start = 0; 656 } 657 #endif 658 page_cgroup_init(); 659 enable_debug_pagealloc(); 660 kmemleak_init(); 661 debug_objects_mem_init(); 662 idr_init_cache(); 663 setup_per_cpu_pageset(); 664 numa_policy_init(); 665 if (late_time_init) 666 late_time_init(); 667 sched_clock_init(); 668 calibrate_delay(); 669 pidmap_init(); 670 anon_vma_init(); 671 #ifdef CONFIG_X86 672 if (efi_enabled) 673 efi_enter_virtual_mode(); 674 #endif 675 thread_info_cache_init(); 676 cred_init(); 677 fork_init(totalram_pages); 678 proc_caches_init(); 679 buffer_init(); 680 key_init(); 681 security_init(); 682 dbg_late_init(); 683 vfs_caches_init(totalram_pages); 684 signals_init(); 685 /* rootfs populating might need page-writeback */ 686 page_writeback_init(); 687 #ifdef CONFIG_PROC_FS 688 proc_root_init(); 689 #endif 690 cgroup_init(); 691 cpuset_init(); 692 taskstats_init_early(); 693 delayacct_init(); 694 695 check_bugs(); 696 697 acpi_early_init(); /* before LAPIC and SMP init */ 698 sfi_init_late(); 699 700 ftrace_init(); 701 702 /* Do the rest non-__init'ed, we're now alive */ 703 rest_init(); 704 } 705 706 /* Call all constructor functions linked into the kernel. */ 707 static void __init do_ctors(void) 708 { 709 #ifdef CONFIG_CONSTRUCTORS 710 ctor_fn_t *fn = (ctor_fn_t *) __ctors_start; 711 712 for (; fn < (ctor_fn_t *) __ctors_end; fn++) 713 (*fn)(); 714 #endif 715 } 716 717 int initcall_debug; 718 core_param(initcall_debug, initcall_debug, bool, 0644); 719 720 static char msgbuf[64]; 721 722 static int __init_or_module do_one_initcall_debug(initcall_t fn) 723 { 724 ktime_t calltime, delta, rettime; 725 unsigned long long duration; 726 int ret; 727 728 printk(KERN_DEBUG "calling %pF @ %i\n", fn, task_pid_nr(current)); 729 calltime = ktime_get(); 730 ret = fn(); 731 rettime = ktime_get(); 732 delta = ktime_sub(rettime, calltime); 733 duration = (unsigned long long) ktime_to_ns(delta) >> 10; 734 printk(KERN_DEBUG "initcall %pF returned %d after %lld usecs\n", fn, 735 ret, duration); 736 737 return ret; 738 } 739 740 int __init_or_module do_one_initcall(initcall_t fn) 741 { 742 int count = preempt_count(); 743 int ret; 744 745 if (initcall_debug) 746 ret = do_one_initcall_debug(fn); 747 else 748 ret = fn(); 749 750 msgbuf[0] = 0; 751 752 if (ret && ret != -ENODEV && initcall_debug) 753 sprintf(msgbuf, "error code %d ", ret); 754 755 if (preempt_count() != count) { 756 strlcat(msgbuf, "preemption imbalance ", sizeof(msgbuf)); 757 preempt_count() = count; 758 } 759 if (irqs_disabled()) { 760 strlcat(msgbuf, "disabled interrupts ", sizeof(msgbuf)); 761 local_irq_enable(); 762 } 763 if (msgbuf[0]) { 764 printk("initcall %pF returned with %s\n", fn, msgbuf); 765 } 766 767 return ret; 768 } 769 770 771 extern initcall_t __initcall_start[], __initcall_end[], __early_initcall_end[]; 772 773 static void __init do_initcalls(void) 774 { 775 initcall_t *fn; 776 777 for (fn = __early_initcall_end; fn < __initcall_end; fn++) 778 do_one_initcall(*fn); 779 780 /* Make sure there is no pending stuff from the initcall sequence */ 781 flush_scheduled_work(); 782 } 783 784 /* 785 * Ok, the machine is now initialized. None of the devices 786 * have been touched yet, but the CPU subsystem is up and 787 * running, and memory and process management works. 788 * 789 * Now we can finally start doing some real work.. 790 */ 791 static void __init do_basic_setup(void) 792 { 793 cpuset_init_smp(); 794 usermodehelper_init(); 795 init_tmpfs(); 796 driver_init(); 797 init_irq_proc(); 798 do_ctors(); 799 do_initcalls(); 800 } 801 802 static void __init do_pre_smp_initcalls(void) 803 { 804 initcall_t *fn; 805 806 for (fn = __initcall_start; fn < __early_initcall_end; fn++) 807 do_one_initcall(*fn); 808 } 809 810 static void run_init_process(const char *init_filename) 811 { 812 argv_init[0] = init_filename; 813 kernel_execve(init_filename, argv_init, envp_init); 814 } 815 816 /* This is a non __init function. Force it to be noinline otherwise gcc 817 * makes it inline to init() and it becomes part of init.text section 818 */ 819 static noinline int init_post(void) 820 { 821 /* need to finish all async __init code before freeing the memory */ 822 async_synchronize_full(); 823 free_initmem(); 824 mark_rodata_ro(); 825 system_state = SYSTEM_RUNNING; 826 numa_default_policy(); 827 828 829 current->signal->flags |= SIGNAL_UNKILLABLE; 830 831 if (ramdisk_execute_command) { 832 run_init_process(ramdisk_execute_command); 833 printk(KERN_WARNING "Failed to execute %s\n", 834 ramdisk_execute_command); 835 } 836 837 /* 838 * We try each of these until one succeeds. 839 * 840 * The Bourne shell can be used instead of init if we are 841 * trying to recover a really broken machine. 842 */ 843 if (execute_command) { 844 run_init_process(execute_command); 845 printk(KERN_WARNING "Failed to execute %s. Attempting " 846 "defaults...\n", execute_command); 847 } 848 run_init_process("/sbin/init"); 849 run_init_process("/etc/init"); 850 run_init_process("/bin/init"); 851 run_init_process("/bin/sh"); 852 853 panic("No init found. Try passing init= option to kernel. " 854 "See Linux Documentation/init.txt for guidance."); 855 } 856 857 static int __init kernel_init(void * unused) 858 { 859 /* 860 * Wait until kthreadd is all set-up. 861 */ 862 wait_for_completion(&kthreadd_done); 863 /* 864 * init can allocate pages on any node 865 */ 866 set_mems_allowed(node_states[N_HIGH_MEMORY]); 867 /* 868 * init can run on any cpu. 869 */ 870 set_cpus_allowed_ptr(current, cpu_all_mask); 871 /* 872 * Tell the world that we're going to be the grim 873 * reaper of innocent orphaned children. 874 * 875 * We don't want people to have to make incorrect 876 * assumptions about where in the task array this 877 * can be found. 878 */ 879 init_pid_ns.child_reaper = current; 880 881 cad_pid = task_pid(current); 882 883 smp_prepare_cpus(setup_max_cpus); 884 885 do_pre_smp_initcalls(); 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