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