1 /* 2 * linux/init/main.c 3 * 4 * Copyright (C) 1991, 1992 Linus Torvalds 5 * 6 * GK 2/5/95 - Changed to support mounting root fs via NFS 7 * Added initrd & change_root: Werner Almesberger & Hans Lermen, Feb '96 8 * Moan early if gcc is old, avoiding bogus kernels - Paul Gortmaker, May '96 9 * Simplified starting of init: Michael A. Griffith <grif@acm.org> 10 */ 11 12 #include <linux/types.h> 13 #include <linux/module.h> 14 #include <linux/proc_fs.h> 15 #include <linux/kernel.h> 16 #include <linux/syscalls.h> 17 #include <linux/stackprotector.h> 18 #include <linux/string.h> 19 #include <linux/ctype.h> 20 #include <linux/delay.h> 21 #include <linux/ioport.h> 22 #include <linux/init.h> 23 #include <linux/initrd.h> 24 #include <linux/bootmem.h> 25 #include <linux/acpi.h> 26 #include <linux/tty.h> 27 #include <linux/percpu.h> 28 #include <linux/kmod.h> 29 #include <linux/vmalloc.h> 30 #include <linux/kernel_stat.h> 31 #include <linux/start_kernel.h> 32 #include <linux/security.h> 33 #include <linux/smp.h> 34 #include <linux/profile.h> 35 #include <linux/rcupdate.h> 36 #include <linux/moduleparam.h> 37 #include <linux/kallsyms.h> 38 #include <linux/writeback.h> 39 #include <linux/cpu.h> 40 #include <linux/cpuset.h> 41 #include <linux/cgroup.h> 42 #include <linux/efi.h> 43 #include <linux/tick.h> 44 #include <linux/interrupt.h> 45 #include <linux/taskstats_kern.h> 46 #include <linux/delayacct.h> 47 #include <linux/unistd.h> 48 #include <linux/rmap.h> 49 #include <linux/mempolicy.h> 50 #include <linux/key.h> 51 #include <linux/buffer_head.h> 52 #include <linux/page_cgroup.h> 53 #include <linux/debug_locks.h> 54 #include <linux/debugobjects.h> 55 #include <linux/lockdep.h> 56 #include <linux/kmemleak.h> 57 #include <linux/pid_namespace.h> 58 #include <linux/device.h> 59 #include <linux/kthread.h> 60 #include <linux/sched.h> 61 #include <linux/signal.h> 62 #include <linux/idr.h> 63 #include <linux/kgdb.h> 64 #include <linux/ftrace.h> 65 #include <linux/async.h> 66 #include <linux/kmemcheck.h> 67 #include <linux/sfi.h> 68 #include <linux/shmem_fs.h> 69 #include <linux/slab.h> 70 #include <linux/perf_event.h> 71 #include <linux/file.h> 72 #include <linux/ptrace.h> 73 74 #include <asm/io.h> 75 #include <asm/bugs.h> 76 #include <asm/setup.h> 77 #include <asm/sections.h> 78 #include <asm/cacheflush.h> 79 80 #ifdef CONFIG_X86_LOCAL_APIC 81 #include <asm/smp.h> 82 #endif 83 84 static int kernel_init(void *); 85 86 extern void init_IRQ(void); 87 extern void fork_init(unsigned long); 88 extern void mca_init(void); 89 extern void sbus_init(void); 90 extern void radix_tree_init(void); 91 #ifndef CONFIG_DEBUG_RODATA 92 static inline void mark_rodata_ro(void) { } 93 #endif 94 95 #ifdef CONFIG_TC 96 extern void tc_init(void); 97 #endif 98 99 /* 100 * Debug helper: via this flag we know that we are in 'early bootup code' 101 * where only the boot processor is running with IRQ disabled. This means 102 * two things - IRQ must not be enabled before the flag is cleared and some 103 * operations which are not allowed with IRQ disabled are allowed while the 104 * flag is set. 105 */ 106 bool early_boot_irqs_disabled __read_mostly; 107 108 enum system_states system_state __read_mostly; 109 EXPORT_SYMBOL(system_state); 110 111 /* 112 * Boot command-line arguments 113 */ 114 #define MAX_INIT_ARGS CONFIG_INIT_ENV_ARG_LIMIT 115 #define MAX_INIT_ENVS CONFIG_INIT_ENV_ARG_LIMIT 116 117 extern void time_init(void); 118 /* Default late time init is NULL. archs can override this later. */ 119 void (*__initdata late_time_init)(void); 120 extern void softirq_init(void); 121 122 /* Untouched command line saved by arch-specific code. */ 123 char __initdata boot_command_line[COMMAND_LINE_SIZE]; 124 /* Untouched saved command line (eg. for /proc) */ 125 char *saved_command_line; 126 /* Command line for parameter parsing */ 127 static char *static_command_line; 128 129 static char *execute_command; 130 static char *ramdisk_execute_command; 131 132 /* 133 * If set, this is an indication to the drivers that reset the underlying 134 * device before going ahead with the initialization otherwise driver might 135 * rely on the BIOS and skip the reset operation. 136 * 137 * This is useful if kernel is booting in an unreliable environment. 138 * For ex. kdump situaiton where previous kernel has crashed, BIOS has been 139 * skipped and devices will be in unknown state. 140 */ 141 unsigned int reset_devices; 142 EXPORT_SYMBOL(reset_devices); 143 144 static int __init set_reset_devices(char *str) 145 { 146 reset_devices = 1; 147 return 1; 148 } 149 150 __setup("reset_devices", set_reset_devices); 151 152 static const char * argv_init[MAX_INIT_ARGS+2] = { "init", NULL, }; 153 const char * envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, }; 154 static const char *panic_later, *panic_param; 155 156 extern const struct obs_kernel_param __setup_start[], __setup_end[]; 157 158 static int __init obsolete_checksetup(char *line) 159 { 160 const struct obs_kernel_param *p; 161 int had_early_param = 0; 162 163 p = __setup_start; 164 do { 165 int n = strlen(p->str); 166 if (parameqn(line, p->str, n)) { 167 if (p->early) { 168 /* Already done in parse_early_param? 169 * (Needs exact match on param part). 170 * Keep iterating, as we can have early 171 * params and __setups of same names 8( */ 172 if (line[n] == '\0' || line[n] == '=') 173 had_early_param = 1; 174 } else if (!p->setup_func) { 175 printk(KERN_WARNING "Parameter %s is obsolete," 176 " ignored\n", p->str); 177 return 1; 178 } else if (p->setup_func(line + n)) 179 return 1; 180 } 181 p++; 182 } while (p < __setup_end); 183 184 return had_early_param; 185 } 186 187 /* 188 * This should be approx 2 Bo*oMips to start (note initial shift), and will 189 * still work even if initially too large, it will just take slightly longer 190 */ 191 unsigned long loops_per_jiffy = (1<<12); 192 193 EXPORT_SYMBOL(loops_per_jiffy); 194 195 static int __init debug_kernel(char *str) 196 { 197 console_loglevel = 10; 198 return 0; 199 } 200 201 static int __init quiet_kernel(char *str) 202 { 203 console_loglevel = 4; 204 return 0; 205 } 206 207 early_param("debug", debug_kernel); 208 early_param("quiet", quiet_kernel); 209 210 static int __init loglevel(char *str) 211 { 212 int newlevel; 213 214 /* 215 * Only update loglevel value when a correct setting was passed, 216 * to prevent blind crashes (when loglevel being set to 0) that 217 * are quite hard to debug 218 */ 219 if (get_option(&str, &newlevel)) { 220 console_loglevel = newlevel; 221 return 0; 222 } 223 224 return -EINVAL; 225 } 226 227 early_param("loglevel", loglevel); 228 229 /* Change NUL term back to "=", to make "param" the whole string. */ 230 static int __init repair_env_string(char *param, char *val, const char *unused) 231 { 232 if (val) { 233 /* param=val or param="val"? */ 234 if (val == param+strlen(param)+1) 235 val[-1] = '='; 236 else if (val == param+strlen(param)+2) { 237 val[-2] = '='; 238 memmove(val-1, val, strlen(val)+1); 239 val--; 240 } else 241 BUG(); 242 } 243 return 0; 244 } 245 246 /* 247 * Unknown boot options get handed to init, unless they look like 248 * unused parameters (modprobe will find them in /proc/cmdline). 249 */ 250 static int __init unknown_bootoption(char *param, char *val, const char *unused) 251 { 252 repair_env_string(param, val, unused); 253 254 /* Handle obsolete-style parameters */ 255 if (obsolete_checksetup(param)) 256 return 0; 257 258 /* Unused module parameter. */ 259 if (strchr(param, '.') && (!val || strchr(param, '.') < val)) 260 return 0; 261 262 if (panic_later) 263 return 0; 264 265 if (val) { 266 /* Environment option */ 267 unsigned int i; 268 for (i = 0; envp_init[i]; i++) { 269 if (i == MAX_INIT_ENVS) { 270 panic_later = "Too many boot env vars at `%s'"; 271 panic_param = param; 272 } 273 if (!strncmp(param, envp_init[i], val - param)) 274 break; 275 } 276 envp_init[i] = param; 277 } else { 278 /* Command line option */ 279 unsigned int i; 280 for (i = 0; argv_init[i]; i++) { 281 if (i == MAX_INIT_ARGS) { 282 panic_later = "Too many boot init vars at `%s'"; 283 panic_param = param; 284 } 285 } 286 argv_init[i] = param; 287 } 288 return 0; 289 } 290 291 static int __init init_setup(char *str) 292 { 293 unsigned int i; 294 295 execute_command = str; 296 /* 297 * In case LILO is going to boot us with default command line, 298 * it prepends "auto" before the whole cmdline which makes 299 * the shell think it should execute a script with such name. 300 * So we ignore all arguments entered _before_ init=... [MJ] 301 */ 302 for (i = 1; i < MAX_INIT_ARGS; i++) 303 argv_init[i] = NULL; 304 return 1; 305 } 306 __setup("init=", init_setup); 307 308 static int __init rdinit_setup(char *str) 309 { 310 unsigned int i; 311 312 ramdisk_execute_command = str; 313 /* See "auto" comment in init_setup */ 314 for (i = 1; i < MAX_INIT_ARGS; i++) 315 argv_init[i] = NULL; 316 return 1; 317 } 318 __setup("rdinit=", rdinit_setup); 319 320 #ifndef CONFIG_SMP 321 static const unsigned int setup_max_cpus = NR_CPUS; 322 #ifdef CONFIG_X86_LOCAL_APIC 323 static void __init smp_init(void) 324 { 325 APIC_init_uniprocessor(); 326 } 327 #else 328 #define smp_init() do { } while (0) 329 #endif 330 331 static inline void setup_nr_cpu_ids(void) { } 332 static inline void smp_prepare_cpus(unsigned int maxcpus) { } 333 #endif 334 335 /* 336 * We need to store the untouched command line for future reference. 337 * We also need to store the touched command line since the parameter 338 * parsing is performed in place, and we should allow a component to 339 * store reference of name/value for future reference. 340 */ 341 static void __init setup_command_line(char *command_line) 342 { 343 saved_command_line = alloc_bootmem(strlen (boot_command_line)+1); 344 static_command_line = alloc_bootmem(strlen (command_line)+1); 345 strcpy (saved_command_line, boot_command_line); 346 strcpy (static_command_line, command_line); 347 } 348 349 /* 350 * We need to finalize in a non-__init function or else race conditions 351 * between the root thread and the init thread may cause start_kernel to 352 * be reaped by free_initmem before the root thread has proceeded to 353 * cpu_idle. 354 * 355 * gcc-3.4 accidentally inlines this function, so use noinline. 356 */ 357 358 static __initdata DECLARE_COMPLETION(kthreadd_done); 359 360 static noinline void __init_refok rest_init(void) 361 { 362 int pid; 363 364 rcu_scheduler_starting(); 365 /* 366 * We need to spawn init first so that it obtains pid 1, however 367 * the init task will end up wanting to create kthreads, which, if 368 * we schedule it before we create kthreadd, will OOPS. 369 */ 370 kernel_thread(kernel_init, NULL, CLONE_FS | CLONE_SIGHAND); 371 numa_default_policy(); 372 pid = kernel_thread(kthreadd, NULL, CLONE_FS | CLONE_FILES); 373 rcu_read_lock(); 374 kthreadd_task = find_task_by_pid_ns(pid, &init_pid_ns); 375 rcu_read_unlock(); 376 complete(&kthreadd_done); 377 378 /* 379 * The boot idle thread must execute schedule() 380 * at least once to get things moving: 381 */ 382 init_idle_bootup_task(current); 383 schedule_preempt_disabled(); 384 /* Call into cpu_idle with preempt disabled */ 385 cpu_idle(); 386 } 387 388 /* Check for early params. */ 389 static int __init do_early_param(char *param, char *val, const char *unused) 390 { 391 const struct obs_kernel_param *p; 392 393 for (p = __setup_start; p < __setup_end; p++) { 394 if ((p->early && parameq(param, p->str)) || 395 (strcmp(param, "console") == 0 && 396 strcmp(p->str, "earlycon") == 0) 397 ) { 398 if (p->setup_func(val) != 0) 399 printk(KERN_WARNING 400 "Malformed early option '%s'\n", param); 401 } 402 } 403 /* We accept everything at this stage. */ 404 return 0; 405 } 406 407 void __init parse_early_options(char *cmdline) 408 { 409 parse_args("early options", cmdline, NULL, 0, 0, 0, do_early_param); 410 } 411 412 /* Arch code calls this early on, or if not, just before other parsing. */ 413 void __init parse_early_param(void) 414 { 415 static __initdata int done = 0; 416 static __initdata char tmp_cmdline[COMMAND_LINE_SIZE]; 417 418 if (done) 419 return; 420 421 /* All fall through to do_early_param. */ 422 strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE); 423 parse_early_options(tmp_cmdline); 424 done = 1; 425 } 426 427 /* 428 * Activate the first processor. 429 */ 430 431 static void __init boot_cpu_init(void) 432 { 433 int cpu = smp_processor_id(); 434 /* Mark the boot cpu "present", "online" etc for SMP and UP case */ 435 set_cpu_online(cpu, true); 436 set_cpu_active(cpu, true); 437 set_cpu_present(cpu, true); 438 set_cpu_possible(cpu, true); 439 } 440 441 void __init __weak smp_setup_processor_id(void) 442 { 443 } 444 445 void __init __weak thread_info_cache_init(void) 446 { 447 } 448 449 /* 450 * Set up kernel memory allocators 451 */ 452 static void __init mm_init(void) 453 { 454 /* 455 * page_cgroup requires contiguous pages, 456 * bigger than MAX_ORDER unless SPARSEMEM. 457 */ 458 page_cgroup_init_flatmem(); 459 mem_init(); 460 kmem_cache_init(); 461 percpu_init_late(); 462 pgtable_cache_init(); 463 vmalloc_init(); 464 } 465 466 asmlinkage void __init start_kernel(void) 467 { 468 char * command_line; 469 extern const struct kernel_param __start___param[], __stop___param[]; 470 471 /* 472 * Need to run as early as possible, to initialize the 473 * lockdep hash: 474 */ 475 lockdep_init(); 476 smp_setup_processor_id(); 477 debug_objects_early_init(); 478 479 /* 480 * Set up the the initial canary ASAP: 481 */ 482 boot_init_stack_canary(); 483 484 cgroup_init_early(); 485 486 local_irq_disable(); 487 early_boot_irqs_disabled = true; 488 489 /* 490 * Interrupts are still disabled. Do necessary setups, then 491 * enable them 492 */ 493 tick_init(); 494 boot_cpu_init(); 495 page_address_init(); 496 printk(KERN_NOTICE "%s", linux_banner); 497 setup_arch(&command_line); 498 mm_init_owner(&init_mm, &init_task); 499 mm_init_cpumask(&init_mm); 500 setup_command_line(command_line); 501 setup_nr_cpu_ids(); 502 setup_per_cpu_areas(); 503 smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */ 504 505 build_all_zonelists(NULL, NULL); 506 page_alloc_init(); 507 508 printk(KERN_NOTICE "Kernel command line: %s\n", boot_command_line); 509 parse_early_param(); 510 parse_args("Booting kernel", static_command_line, __start___param, 511 __stop___param - __start___param, 512 -1, -1, &unknown_bootoption); 513 514 jump_label_init(); 515 516 /* 517 * These use large bootmem allocations and must precede 518 * kmem_cache_init() 519 */ 520 setup_log_buf(0); 521 pidhash_init(); 522 vfs_caches_init_early(); 523 sort_main_extable(); 524 trap_init(); 525 mm_init(); 526 527 /* 528 * Set up the scheduler prior starting any interrupts (such as the 529 * timer interrupt). Full topology setup happens at smp_init() 530 * time - but meanwhile we still have a functioning scheduler. 531 */ 532 sched_init(); 533 /* 534 * Disable preemption - early bootup scheduling is extremely 535 * fragile until we cpu_idle() for the first time. 536 */ 537 preempt_disable(); 538 if (!irqs_disabled()) { 539 printk(KERN_WARNING "start_kernel(): bug: interrupts were " 540 "enabled *very* early, fixing it\n"); 541 local_irq_disable(); 542 } 543 idr_init_cache(); 544 perf_event_init(); 545 rcu_init(); 546 radix_tree_init(); 547 /* init some links before init_ISA_irqs() */ 548 early_irq_init(); 549 init_IRQ(); 550 init_timers(); 551 hrtimers_init(); 552 softirq_init(); 553 timekeeping_init(); 554 time_init(); 555 profile_init(); 556 call_function_init(); 557 if (!irqs_disabled()) 558 printk(KERN_CRIT "start_kernel(): bug: interrupts were " 559 "enabled early\n"); 560 early_boot_irqs_disabled = false; 561 local_irq_enable(); 562 563 kmem_cache_init_late(); 564 565 /* 566 * HACK ALERT! This is early. We're enabling the console before 567 * we've done PCI setups etc, and console_init() must be aware of 568 * this. But we do want output early, in case something goes wrong. 569 */ 570 console_init(); 571 if (panic_later) 572 panic(panic_later, panic_param); 573 574 lockdep_info(); 575 576 /* 577 * Need to run this when irqs are enabled, because it wants 578 * to self-test [hard/soft]-irqs on/off lock inversion bugs 579 * too: 580 */ 581 locking_selftest(); 582 583 #ifdef CONFIG_BLK_DEV_INITRD 584 if (initrd_start && !initrd_below_start_ok && 585 page_to_pfn(virt_to_page((void *)initrd_start)) < min_low_pfn) { 586 printk(KERN_CRIT "initrd overwritten (0x%08lx < 0x%08lx) - " 587 "disabling it.\n", 588 page_to_pfn(virt_to_page((void *)initrd_start)), 589 min_low_pfn); 590 initrd_start = 0; 591 } 592 #endif 593 page_cgroup_init(); 594 debug_objects_mem_init(); 595 kmemleak_init(); 596 setup_per_cpu_pageset(); 597 numa_policy_init(); 598 if (late_time_init) 599 late_time_init(); 600 sched_clock_init(); 601 calibrate_delay(); 602 pidmap_init(); 603 anon_vma_init(); 604 #ifdef CONFIG_X86 605 if (efi_enabled) 606 efi_enter_virtual_mode(); 607 #endif 608 thread_info_cache_init(); 609 cred_init(); 610 fork_init(totalram_pages); 611 proc_caches_init(); 612 buffer_init(); 613 key_init(); 614 security_init(); 615 dbg_late_init(); 616 vfs_caches_init(totalram_pages); 617 signals_init(); 618 /* rootfs populating might need page-writeback */ 619 page_writeback_init(); 620 #ifdef CONFIG_PROC_FS 621 proc_root_init(); 622 #endif 623 cgroup_init(); 624 cpuset_init(); 625 taskstats_init_early(); 626 delayacct_init(); 627 628 check_bugs(); 629 630 acpi_early_init(); /* before LAPIC and SMP init */ 631 sfi_init_late(); 632 633 if (efi_enabled) { 634 efi_late_init(); 635 efi_free_boot_services(); 636 } 637 638 ftrace_init(); 639 640 /* Do the rest non-__init'ed, we're now alive */ 641 rest_init(); 642 } 643 644 /* Call all constructor functions linked into the kernel. */ 645 static void __init do_ctors(void) 646 { 647 #ifdef CONFIG_CONSTRUCTORS 648 ctor_fn_t *fn = (ctor_fn_t *) __ctors_start; 649 650 for (; fn < (ctor_fn_t *) __ctors_end; fn++) 651 (*fn)(); 652 #endif 653 } 654 655 bool initcall_debug; 656 core_param(initcall_debug, initcall_debug, bool, 0644); 657 658 static char msgbuf[64]; 659 660 static int __init_or_module do_one_initcall_debug(initcall_t fn) 661 { 662 ktime_t calltime, delta, rettime; 663 unsigned long long duration; 664 int ret; 665 666 printk(KERN_DEBUG "calling %pF @ %i\n", fn, task_pid_nr(current)); 667 calltime = ktime_get(); 668 ret = fn(); 669 rettime = ktime_get(); 670 delta = ktime_sub(rettime, calltime); 671 duration = (unsigned long long) ktime_to_ns(delta) >> 10; 672 printk(KERN_DEBUG "initcall %pF returned %d after %lld usecs\n", fn, 673 ret, duration); 674 675 return ret; 676 } 677 678 int __init_or_module do_one_initcall(initcall_t fn) 679 { 680 int count = preempt_count(); 681 int ret; 682 683 if (initcall_debug) 684 ret = do_one_initcall_debug(fn); 685 else 686 ret = fn(); 687 688 msgbuf[0] = 0; 689 690 if (ret && ret != -ENODEV && initcall_debug) 691 sprintf(msgbuf, "error code %d ", ret); 692 693 if (preempt_count() != count) { 694 strlcat(msgbuf, "preemption imbalance ", sizeof(msgbuf)); 695 preempt_count() = count; 696 } 697 if (irqs_disabled()) { 698 strlcat(msgbuf, "disabled interrupts ", sizeof(msgbuf)); 699 local_irq_enable(); 700 } 701 if (msgbuf[0]) { 702 printk("initcall %pF returned with %s\n", fn, msgbuf); 703 } 704 705 return ret; 706 } 707 708 709 extern initcall_t __initcall_start[]; 710 extern initcall_t __initcall0_start[]; 711 extern initcall_t __initcall1_start[]; 712 extern initcall_t __initcall2_start[]; 713 extern initcall_t __initcall3_start[]; 714 extern initcall_t __initcall4_start[]; 715 extern initcall_t __initcall5_start[]; 716 extern initcall_t __initcall6_start[]; 717 extern initcall_t __initcall7_start[]; 718 extern initcall_t __initcall_end[]; 719 720 static initcall_t *initcall_levels[] __initdata = { 721 __initcall0_start, 722 __initcall1_start, 723 __initcall2_start, 724 __initcall3_start, 725 __initcall4_start, 726 __initcall5_start, 727 __initcall6_start, 728 __initcall7_start, 729 __initcall_end, 730 }; 731 732 /* Keep these in sync with initcalls in include/linux/init.h */ 733 static char *initcall_level_names[] __initdata = { 734 "early", 735 "core", 736 "postcore", 737 "arch", 738 "subsys", 739 "fs", 740 "device", 741 "late", 742 }; 743 744 static void __init do_initcall_level(int level) 745 { 746 extern const struct kernel_param __start___param[], __stop___param[]; 747 initcall_t *fn; 748 749 strcpy(static_command_line, saved_command_line); 750 parse_args(initcall_level_names[level], 751 static_command_line, __start___param, 752 __stop___param - __start___param, 753 level, level, 754 &repair_env_string); 755 756 for (fn = initcall_levels[level]; fn < initcall_levels[level+1]; fn++) 757 do_one_initcall(*fn); 758 } 759 760 static void __init do_initcalls(void) 761 { 762 int level; 763 764 for (level = 0; level < ARRAY_SIZE(initcall_levels) - 1; level++) 765 do_initcall_level(level); 766 } 767 768 /* 769 * Ok, the machine is now initialized. None of the devices 770 * have been touched yet, but the CPU subsystem is up and 771 * running, and memory and process management works. 772 * 773 * Now we can finally start doing some real work.. 774 */ 775 static void __init do_basic_setup(void) 776 { 777 cpuset_init_smp(); 778 usermodehelper_init(); 779 shmem_init(); 780 driver_init(); 781 init_irq_proc(); 782 do_ctors(); 783 usermodehelper_enable(); 784 do_initcalls(); 785 } 786 787 static void __init do_pre_smp_initcalls(void) 788 { 789 initcall_t *fn; 790 791 for (fn = __initcall_start; fn < __initcall0_start; fn++) 792 do_one_initcall(*fn); 793 } 794 795 static int run_init_process(const char *init_filename) 796 { 797 argv_init[0] = init_filename; 798 return kernel_execve(init_filename, argv_init, envp_init); 799 } 800 801 static void __init kernel_init_freeable(void); 802 803 static int __ref kernel_init(void *unused) 804 { 805 kernel_init_freeable(); 806 /* need to finish all async __init code before freeing the memory */ 807 async_synchronize_full(); 808 free_initmem(); 809 mark_rodata_ro(); 810 system_state = SYSTEM_RUNNING; 811 numa_default_policy(); 812 813 current->signal->flags |= SIGNAL_UNKILLABLE; 814 flush_delayed_fput(); 815 816 if (ramdisk_execute_command) { 817 if (!run_init_process(ramdisk_execute_command)) 818 return 0; 819 printk(KERN_WARNING "Failed to execute %s\n", 820 ramdisk_execute_command); 821 } 822 823 /* 824 * We try each of these until one succeeds. 825 * 826 * The Bourne shell can be used instead of init if we are 827 * trying to recover a really broken machine. 828 */ 829 if (execute_command) { 830 if (!run_init_process(execute_command)) 831 return 0; 832 printk(KERN_WARNING "Failed to execute %s. Attempting " 833 "defaults...\n", execute_command); 834 } 835 if (!run_init_process("/sbin/init") || 836 !run_init_process("/etc/init") || 837 !run_init_process("/bin/init") || 838 !run_init_process("/bin/sh")) 839 return 0; 840 841 panic("No init found. Try passing init= option to kernel. " 842 "See Linux Documentation/init.txt for guidance."); 843 } 844 845 static void __init kernel_init_freeable(void) 846 { 847 /* 848 * Wait until kthreadd is all set-up. 849 */ 850 wait_for_completion(&kthreadd_done); 851 852 /* Now the scheduler is fully set up and can do blocking allocations */ 853 gfp_allowed_mask = __GFP_BITS_MASK; 854 855 /* 856 * init can allocate pages on any node 857 */ 858 set_mems_allowed(node_states[N_HIGH_MEMORY]); 859 /* 860 * init can run on any cpu. 861 */ 862 set_cpus_allowed_ptr(current, cpu_all_mask); 863 864 cad_pid = task_pid(current); 865 866 smp_prepare_cpus(setup_max_cpus); 867 868 do_pre_smp_initcalls(); 869 lockup_detector_init(); 870 871 smp_init(); 872 sched_init_smp(); 873 874 do_basic_setup(); 875 876 /* Open the /dev/console on the rootfs, this should never fail */ 877 if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0) 878 printk(KERN_WARNING "Warning: unable to open an initial console.\n"); 879 880 (void) sys_dup(0); 881 (void) sys_dup(0); 882 /* 883 * check if there is an early userspace init. If yes, let it do all 884 * the work 885 */ 886 887 if (!ramdisk_execute_command) 888 ramdisk_execute_command = "/init"; 889 890 if (sys_access((const char __user *) ramdisk_execute_command, 0) != 0) { 891 ramdisk_execute_command = NULL; 892 prepare_namespace(); 893 } 894 895 /* 896 * Ok, we have completed the initial bootup, and 897 * we're essentially up and running. Get rid of the 898 * initmem segments and start the user-mode stuff.. 899 */ 900 } 901