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 #define DEBUG /* Enable initcall_debug */ 13 14 #include <linux/types.h> 15 #include <linux/module.h> 16 #include <linux/proc_fs.h> 17 #include <linux/kernel.h> 18 #include <linux/syscalls.h> 19 #include <linux/stackprotector.h> 20 #include <linux/string.h> 21 #include <linux/ctype.h> 22 #include <linux/delay.h> 23 #include <linux/ioport.h> 24 #include <linux/init.h> 25 #include <linux/initrd.h> 26 #include <linux/bootmem.h> 27 #include <linux/acpi.h> 28 #include <linux/tty.h> 29 #include <linux/percpu.h> 30 #include <linux/kmod.h> 31 #include <linux/vmalloc.h> 32 #include <linux/kernel_stat.h> 33 #include <linux/start_kernel.h> 34 #include <linux/security.h> 35 #include <linux/smp.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/sfi.h> 70 #include <linux/shmem_fs.h> 71 #include <linux/slab.h> 72 #include <linux/perf_event.h> 73 #include <linux/file.h> 74 #include <linux/ptrace.h> 75 #include <linux/blkdev.h> 76 #include <linux/elevator.h> 77 #include <linux/sched_clock.h> 78 79 #include <asm/io.h> 80 #include <asm/bugs.h> 81 #include <asm/setup.h> 82 #include <asm/sections.h> 83 #include <asm/cacheflush.h> 84 85 #ifdef CONFIG_X86_LOCAL_APIC 86 #include <asm/smp.h> 87 #endif 88 89 static int kernel_init(void *); 90 91 extern void init_IRQ(void); 92 extern void fork_init(unsigned long); 93 extern void mca_init(void); 94 extern void sbus_init(void); 95 extern void radix_tree_init(void); 96 #ifndef CONFIG_DEBUG_RODATA 97 static inline void mark_rodata_ro(void) { } 98 #endif 99 100 #ifdef CONFIG_TC 101 extern void tc_init(void); 102 #endif 103 104 /* 105 * Debug helper: via this flag we know that we are in 'early bootup code' 106 * where only the boot processor is running with IRQ disabled. This means 107 * two things - IRQ must not be enabled before the flag is cleared and some 108 * operations which are not allowed with IRQ disabled are allowed while the 109 * flag is set. 110 */ 111 bool early_boot_irqs_disabled __read_mostly; 112 113 enum system_states system_state __read_mostly; 114 EXPORT_SYMBOL(system_state); 115 116 /* 117 * Boot command-line arguments 118 */ 119 #define MAX_INIT_ARGS CONFIG_INIT_ENV_ARG_LIMIT 120 #define MAX_INIT_ENVS CONFIG_INIT_ENV_ARG_LIMIT 121 122 extern void time_init(void); 123 /* Default late time init is NULL. archs can override this later. */ 124 void (*__initdata late_time_init)(void); 125 extern void softirq_init(void); 126 127 /* Untouched command line saved by arch-specific code. */ 128 char __initdata boot_command_line[COMMAND_LINE_SIZE]; 129 /* Untouched saved command line (eg. for /proc) */ 130 char *saved_command_line; 131 /* Command line for parameter parsing */ 132 static char *static_command_line; 133 134 static char *execute_command; 135 static char *ramdisk_execute_command; 136 137 /* 138 * If set, this is an indication to the drivers that reset the underlying 139 * device before going ahead with the initialization otherwise driver might 140 * rely on the BIOS and skip the reset operation. 141 * 142 * This is useful if kernel is booting in an unreliable environment. 143 * For ex. kdump situaiton where previous kernel has crashed, BIOS has been 144 * skipped and devices will be in unknown state. 145 */ 146 unsigned int reset_devices; 147 EXPORT_SYMBOL(reset_devices); 148 149 static int __init set_reset_devices(char *str) 150 { 151 reset_devices = 1; 152 return 1; 153 } 154 155 __setup("reset_devices", set_reset_devices); 156 157 static const char * argv_init[MAX_INIT_ARGS+2] = { "init", NULL, }; 158 const char * envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, }; 159 static const char *panic_later, *panic_param; 160 161 extern const struct obs_kernel_param __setup_start[], __setup_end[]; 162 163 static int __init obsolete_checksetup(char *line) 164 { 165 const struct obs_kernel_param *p; 166 int had_early_param = 0; 167 168 p = __setup_start; 169 do { 170 int n = strlen(p->str); 171 if (parameqn(line, p->str, n)) { 172 if (p->early) { 173 /* Already done in parse_early_param? 174 * (Needs exact match on param part). 175 * Keep iterating, as we can have early 176 * params and __setups of same names 8( */ 177 if (line[n] == '\0' || line[n] == '=') 178 had_early_param = 1; 179 } else if (!p->setup_func) { 180 pr_warn("Parameter %s is obsolete, ignored\n", 181 p->str); 182 return 1; 183 } else if (p->setup_func(line + n)) 184 return 1; 185 } 186 p++; 187 } while (p < __setup_end); 188 189 return had_early_param; 190 } 191 192 /* 193 * This should be approx 2 Bo*oMips to start (note initial shift), and will 194 * still work even if initially too large, it will just take slightly longer 195 */ 196 unsigned long loops_per_jiffy = (1<<12); 197 198 EXPORT_SYMBOL(loops_per_jiffy); 199 200 static int __init debug_kernel(char *str) 201 { 202 console_loglevel = 10; 203 return 0; 204 } 205 206 static int __init quiet_kernel(char *str) 207 { 208 console_loglevel = 4; 209 return 0; 210 } 211 212 early_param("debug", debug_kernel); 213 early_param("quiet", quiet_kernel); 214 215 static int __init loglevel(char *str) 216 { 217 int newlevel; 218 219 /* 220 * Only update loglevel value when a correct setting was passed, 221 * to prevent blind crashes (when loglevel being set to 0) that 222 * are quite hard to debug 223 */ 224 if (get_option(&str, &newlevel)) { 225 console_loglevel = newlevel; 226 return 0; 227 } 228 229 return -EINVAL; 230 } 231 232 early_param("loglevel", loglevel); 233 234 /* Change NUL term back to "=", to make "param" the whole string. */ 235 static int __init repair_env_string(char *param, char *val, const char *unused) 236 { 237 if (val) { 238 /* param=val or param="val"? */ 239 if (val == param+strlen(param)+1) 240 val[-1] = '='; 241 else if (val == param+strlen(param)+2) { 242 val[-2] = '='; 243 memmove(val-1, val, strlen(val)+1); 244 val--; 245 } else 246 BUG(); 247 } 248 return 0; 249 } 250 251 /* 252 * Unknown boot options get handed to init, unless they look like 253 * unused parameters (modprobe will find them in /proc/cmdline). 254 */ 255 static int __init unknown_bootoption(char *param, char *val, const char *unused) 256 { 257 repair_env_string(param, val, unused); 258 259 /* Handle obsolete-style parameters */ 260 if (obsolete_checksetup(param)) 261 return 0; 262 263 /* Unused module parameter. */ 264 if (strchr(param, '.') && (!val || strchr(param, '.') < val)) 265 return 0; 266 267 if (panic_later) 268 return 0; 269 270 if (val) { 271 /* Environment option */ 272 unsigned int i; 273 for (i = 0; envp_init[i]; i++) { 274 if (i == MAX_INIT_ENVS) { 275 panic_later = "Too many boot env vars at `%s'"; 276 panic_param = param; 277 } 278 if (!strncmp(param, envp_init[i], val - param)) 279 break; 280 } 281 envp_init[i] = param; 282 } else { 283 /* Command line option */ 284 unsigned int i; 285 for (i = 0; argv_init[i]; i++) { 286 if (i == MAX_INIT_ARGS) { 287 panic_later = "Too many boot init vars at `%s'"; 288 panic_param = param; 289 } 290 } 291 argv_init[i] = param; 292 } 293 return 0; 294 } 295 296 static int __init init_setup(char *str) 297 { 298 unsigned int i; 299 300 execute_command = str; 301 /* 302 * In case LILO is going to boot us with default command line, 303 * it prepends "auto" before the whole cmdline which makes 304 * the shell think it should execute a script with such name. 305 * So we ignore all arguments entered _before_ init=... [MJ] 306 */ 307 for (i = 1; i < MAX_INIT_ARGS; i++) 308 argv_init[i] = NULL; 309 return 1; 310 } 311 __setup("init=", init_setup); 312 313 static int __init rdinit_setup(char *str) 314 { 315 unsigned int i; 316 317 ramdisk_execute_command = str; 318 /* See "auto" comment in init_setup */ 319 for (i = 1; i < MAX_INIT_ARGS; i++) 320 argv_init[i] = NULL; 321 return 1; 322 } 323 __setup("rdinit=", rdinit_setup); 324 325 #ifndef CONFIG_SMP 326 static const unsigned int setup_max_cpus = NR_CPUS; 327 #ifdef CONFIG_X86_LOCAL_APIC 328 static void __init smp_init(void) 329 { 330 APIC_init_uniprocessor(); 331 } 332 #else 333 #define smp_init() do { } while (0) 334 #endif 335 336 static inline void setup_nr_cpu_ids(void) { } 337 static inline void smp_prepare_cpus(unsigned int maxcpus) { } 338 #endif 339 340 /* 341 * We need to store the untouched command line for future reference. 342 * We also need to store the touched command line since the parameter 343 * parsing is performed in place, and we should allow a component to 344 * store reference of name/value for future reference. 345 */ 346 static void __init setup_command_line(char *command_line) 347 { 348 saved_command_line = alloc_bootmem(strlen (boot_command_line)+1); 349 static_command_line = alloc_bootmem(strlen (command_line)+1); 350 strcpy (saved_command_line, boot_command_line); 351 strcpy (static_command_line, command_line); 352 } 353 354 /* 355 * We need to finalize in a non-__init function or else race conditions 356 * between the root thread and the init thread may cause start_kernel to 357 * be reaped by free_initmem before the root thread has proceeded to 358 * cpu_idle. 359 * 360 * gcc-3.4 accidentally inlines this function, so use noinline. 361 */ 362 363 static __initdata DECLARE_COMPLETION(kthreadd_done); 364 365 static noinline void __init_refok rest_init(void) 366 { 367 int pid; 368 369 rcu_scheduler_starting(); 370 /* 371 * We need to spawn init first so that it obtains pid 1, however 372 * the init task will end up wanting to create kthreads, which, if 373 * we schedule it before we create kthreadd, will OOPS. 374 */ 375 kernel_thread(kernel_init, NULL, CLONE_FS | CLONE_SIGHAND); 376 numa_default_policy(); 377 pid = kernel_thread(kthreadd, NULL, CLONE_FS | CLONE_FILES); 378 rcu_read_lock(); 379 kthreadd_task = find_task_by_pid_ns(pid, &init_pid_ns); 380 rcu_read_unlock(); 381 complete(&kthreadd_done); 382 383 /* 384 * The boot idle thread must execute schedule() 385 * at least once to get things moving: 386 */ 387 init_idle_bootup_task(current); 388 schedule_preempt_disabled(); 389 /* Call into cpu_idle with preempt disabled */ 390 cpu_startup_entry(CPUHP_ONLINE); 391 } 392 393 /* Check for early params. */ 394 static int __init do_early_param(char *param, char *val, const char *unused) 395 { 396 const struct obs_kernel_param *p; 397 398 for (p = __setup_start; p < __setup_end; p++) { 399 if ((p->early && parameq(param, p->str)) || 400 (strcmp(param, "console") == 0 && 401 strcmp(p->str, "earlycon") == 0) 402 ) { 403 if (p->setup_func(val) != 0) 404 pr_warn("Malformed early option '%s'\n", param); 405 } 406 } 407 /* We accept everything at this stage. */ 408 return 0; 409 } 410 411 void __init parse_early_options(char *cmdline) 412 { 413 parse_args("early options", cmdline, NULL, 0, 0, 0, do_early_param); 414 } 415 416 /* Arch code calls this early on, or if not, just before other parsing. */ 417 void __init parse_early_param(void) 418 { 419 static __initdata int done = 0; 420 static __initdata char tmp_cmdline[COMMAND_LINE_SIZE]; 421 422 if (done) 423 return; 424 425 /* All fall through to do_early_param. */ 426 strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE); 427 parse_early_options(tmp_cmdline); 428 done = 1; 429 } 430 431 /* 432 * Activate the first processor. 433 */ 434 435 static void __init boot_cpu_init(void) 436 { 437 int cpu = smp_processor_id(); 438 /* Mark the boot cpu "present", "online" etc for SMP and UP case */ 439 set_cpu_online(cpu, true); 440 set_cpu_active(cpu, true); 441 set_cpu_present(cpu, true); 442 set_cpu_possible(cpu, true); 443 } 444 445 void __init __weak smp_setup_processor_id(void) 446 { 447 } 448 449 # if THREAD_SIZE >= PAGE_SIZE 450 void __init __weak thread_info_cache_init(void) 451 { 452 } 453 #endif 454 455 /* 456 * Set up kernel memory allocators 457 */ 458 static void __init mm_init(void) 459 { 460 /* 461 * page_cgroup requires contiguous pages, 462 * bigger than MAX_ORDER unless SPARSEMEM. 463 */ 464 page_cgroup_init_flatmem(); 465 mem_init(); 466 kmem_cache_init(); 467 percpu_init_late(); 468 pgtable_cache_init(); 469 vmalloc_init(); 470 } 471 472 asmlinkage void __init start_kernel(void) 473 { 474 char * command_line; 475 extern const struct kernel_param __start___param[], __stop___param[]; 476 477 /* 478 * Need to run as early as possible, to initialize the 479 * lockdep hash: 480 */ 481 lockdep_init(); 482 smp_setup_processor_id(); 483 debug_objects_early_init(); 484 485 /* 486 * Set up the the initial canary ASAP: 487 */ 488 boot_init_stack_canary(); 489 490 cgroup_init_early(); 491 492 local_irq_disable(); 493 early_boot_irqs_disabled = true; 494 495 /* 496 * Interrupts are still disabled. Do necessary setups, then 497 * enable them 498 */ 499 boot_cpu_init(); 500 page_address_init(); 501 pr_notice("%s", linux_banner); 502 setup_arch(&command_line); 503 mm_init_owner(&init_mm, &init_task); 504 mm_init_cpumask(&init_mm); 505 setup_command_line(command_line); 506 setup_nr_cpu_ids(); 507 setup_per_cpu_areas(); 508 smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */ 509 510 build_all_zonelists(NULL, NULL); 511 page_alloc_init(); 512 513 pr_notice("Kernel command line: %s\n", boot_command_line); 514 parse_early_param(); 515 parse_args("Booting kernel", static_command_line, __start___param, 516 __stop___param - __start___param, 517 -1, -1, &unknown_bootoption); 518 519 jump_label_init(); 520 521 /* 522 * These use large bootmem allocations and must precede 523 * kmem_cache_init() 524 */ 525 setup_log_buf(0); 526 pidhash_init(); 527 vfs_caches_init_early(); 528 sort_main_extable(); 529 trap_init(); 530 mm_init(); 531 532 /* 533 * Set up the scheduler prior starting any interrupts (such as the 534 * timer interrupt). Full topology setup happens at smp_init() 535 * time - but meanwhile we still have a functioning scheduler. 536 */ 537 sched_init(); 538 /* 539 * Disable preemption - early bootup scheduling is extremely 540 * fragile until we cpu_idle() for the first time. 541 */ 542 preempt_disable(); 543 if (WARN(!irqs_disabled(), "Interrupts were enabled *very* early, fixing it\n")) 544 local_irq_disable(); 545 idr_init_cache(); 546 rcu_init(); 547 tick_nohz_init(); 548 radix_tree_init(); 549 /* init some links before init_ISA_irqs() */ 550 early_irq_init(); 551 init_IRQ(); 552 tick_init(); 553 init_timers(); 554 hrtimers_init(); 555 softirq_init(); 556 timekeeping_init(); 557 time_init(); 558 sched_clock_postinit(); 559 perf_event_init(); 560 profile_init(); 561 call_function_init(); 562 WARN(!irqs_disabled(), "Interrupts were enabled early\n"); 563 early_boot_irqs_disabled = false; 564 local_irq_enable(); 565 566 kmem_cache_init_late(); 567 568 /* 569 * HACK ALERT! This is early. We're enabling the console before 570 * we've done PCI setups etc, and console_init() must be aware of 571 * this. But we do want output early, in case something goes wrong. 572 */ 573 console_init(); 574 if (panic_later) 575 panic(panic_later, panic_param); 576 577 lockdep_info(); 578 579 /* 580 * Need to run this when irqs are enabled, because it wants 581 * to self-test [hard/soft]-irqs on/off lock inversion bugs 582 * too: 583 */ 584 locking_selftest(); 585 586 #ifdef CONFIG_BLK_DEV_INITRD 587 if (initrd_start && !initrd_below_start_ok && 588 page_to_pfn(virt_to_page((void *)initrd_start)) < min_low_pfn) { 589 pr_crit("initrd overwritten (0x%08lx < 0x%08lx) - disabling it.\n", 590 page_to_pfn(virt_to_page((void *)initrd_start)), 591 min_low_pfn); 592 initrd_start = 0; 593 } 594 #endif 595 page_cgroup_init(); 596 debug_objects_mem_init(); 597 kmemleak_init(); 598 setup_per_cpu_pageset(); 599 numa_policy_init(); 600 if (late_time_init) 601 late_time_init(); 602 sched_clock_init(); 603 calibrate_delay(); 604 pidmap_init(); 605 anon_vma_init(); 606 #ifdef CONFIG_X86 607 if (efi_enabled(EFI_RUNTIME_SERVICES)) 608 efi_enter_virtual_mode(); 609 #endif 610 thread_info_cache_init(); 611 cred_init(); 612 fork_init(totalram_pages); 613 proc_caches_init(); 614 buffer_init(); 615 key_init(); 616 security_init(); 617 dbg_late_init(); 618 vfs_caches_init(totalram_pages); 619 signals_init(); 620 /* rootfs populating might need page-writeback */ 621 page_writeback_init(); 622 #ifdef CONFIG_PROC_FS 623 proc_root_init(); 624 #endif 625 cgroup_init(); 626 cpuset_init(); 627 taskstats_init_early(); 628 delayacct_init(); 629 630 check_bugs(); 631 632 acpi_early_init(); /* before LAPIC and SMP init */ 633 sfi_init_late(); 634 635 if (efi_enabled(EFI_RUNTIME_SERVICES)) { 636 efi_late_init(); 637 efi_free_boot_services(); 638 } 639 640 ftrace_init(); 641 642 /* Do the rest non-__init'ed, we're now alive */ 643 rest_init(); 644 } 645 646 /* Call all constructor functions linked into the kernel. */ 647 static void __init do_ctors(void) 648 { 649 #ifdef CONFIG_CONSTRUCTORS 650 ctor_fn_t *fn = (ctor_fn_t *) __ctors_start; 651 652 for (; fn < (ctor_fn_t *) __ctors_end; fn++) 653 (*fn)(); 654 #endif 655 } 656 657 bool initcall_debug; 658 core_param(initcall_debug, initcall_debug, bool, 0644); 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 pr_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 pr_debug("initcall %pF returned %d after %lld usecs\n", 673 fn, 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 char msgbuf[64]; 683 684 if (initcall_debug) 685 ret = do_one_initcall_debug(fn); 686 else 687 ret = fn(); 688 689 msgbuf[0] = 0; 690 691 if (preempt_count() != count) { 692 sprintf(msgbuf, "preemption imbalance "); 693 preempt_count() = count; 694 } 695 if (irqs_disabled()) { 696 strlcat(msgbuf, "disabled interrupts ", sizeof(msgbuf)); 697 local_irq_enable(); 698 } 699 WARN(msgbuf[0], "initcall %pF returned with %s\n", fn, msgbuf); 700 701 return ret; 702 } 703 704 705 extern initcall_t __initcall_start[]; 706 extern initcall_t __initcall0_start[]; 707 extern initcall_t __initcall1_start[]; 708 extern initcall_t __initcall2_start[]; 709 extern initcall_t __initcall3_start[]; 710 extern initcall_t __initcall4_start[]; 711 extern initcall_t __initcall5_start[]; 712 extern initcall_t __initcall6_start[]; 713 extern initcall_t __initcall7_start[]; 714 extern initcall_t __initcall_end[]; 715 716 static initcall_t *initcall_levels[] __initdata = { 717 __initcall0_start, 718 __initcall1_start, 719 __initcall2_start, 720 __initcall3_start, 721 __initcall4_start, 722 __initcall5_start, 723 __initcall6_start, 724 __initcall7_start, 725 __initcall_end, 726 }; 727 728 /* Keep these in sync with initcalls in include/linux/init.h */ 729 static char *initcall_level_names[] __initdata = { 730 "early", 731 "core", 732 "postcore", 733 "arch", 734 "subsys", 735 "fs", 736 "device", 737 "late", 738 }; 739 740 static void __init do_initcall_level(int level) 741 { 742 extern const struct kernel_param __start___param[], __stop___param[]; 743 initcall_t *fn; 744 745 strcpy(static_command_line, saved_command_line); 746 parse_args(initcall_level_names[level], 747 static_command_line, __start___param, 748 __stop___param - __start___param, 749 level, level, 750 &repair_env_string); 751 752 for (fn = initcall_levels[level]; fn < initcall_levels[level+1]; fn++) 753 do_one_initcall(*fn); 754 } 755 756 static void __init do_initcalls(void) 757 { 758 int level; 759 760 for (level = 0; level < ARRAY_SIZE(initcall_levels) - 1; level++) 761 do_initcall_level(level); 762 } 763 764 /* 765 * Ok, the machine is now initialized. None of the devices 766 * have been touched yet, but the CPU subsystem is up and 767 * running, and memory and process management works. 768 * 769 * Now we can finally start doing some real work.. 770 */ 771 static void __init do_basic_setup(void) 772 { 773 cpuset_init_smp(); 774 usermodehelper_init(); 775 shmem_init(); 776 driver_init(); 777 init_irq_proc(); 778 do_ctors(); 779 usermodehelper_enable(); 780 do_initcalls(); 781 } 782 783 static void __init do_pre_smp_initcalls(void) 784 { 785 initcall_t *fn; 786 787 for (fn = __initcall_start; fn < __initcall0_start; fn++) 788 do_one_initcall(*fn); 789 } 790 791 /* 792 * This function requests modules which should be loaded by default and is 793 * called twice right after initrd is mounted and right before init is 794 * exec'd. If such modules are on either initrd or rootfs, they will be 795 * loaded before control is passed to userland. 796 */ 797 void __init load_default_modules(void) 798 { 799 load_default_elevator_module(); 800 } 801 802 static int run_init_process(const char *init_filename) 803 { 804 argv_init[0] = init_filename; 805 return do_execve(init_filename, 806 (const char __user *const __user *)argv_init, 807 (const char __user *const __user *)envp_init); 808 } 809 810 static noinline void __init kernel_init_freeable(void); 811 812 static int __ref kernel_init(void *unused) 813 { 814 kernel_init_freeable(); 815 /* need to finish all async __init code before freeing the memory */ 816 async_synchronize_full(); 817 free_initmem(); 818 mark_rodata_ro(); 819 system_state = SYSTEM_RUNNING; 820 numa_default_policy(); 821 822 flush_delayed_fput(); 823 824 if (ramdisk_execute_command) { 825 if (!run_init_process(ramdisk_execute_command)) 826 return 0; 827 pr_err("Failed to execute %s\n", ramdisk_execute_command); 828 } 829 830 /* 831 * We try each of these until one succeeds. 832 * 833 * The Bourne shell can be used instead of init if we are 834 * trying to recover a really broken machine. 835 */ 836 if (execute_command) { 837 if (!run_init_process(execute_command)) 838 return 0; 839 pr_err("Failed to execute %s. Attempting defaults...\n", 840 execute_command); 841 } 842 if (!run_init_process("/sbin/init") || 843 !run_init_process("/etc/init") || 844 !run_init_process("/bin/init") || 845 !run_init_process("/bin/sh")) 846 return 0; 847 848 panic("No init found. Try passing init= option to kernel. " 849 "See Linux Documentation/init.txt for guidance."); 850 } 851 852 static noinline void __init kernel_init_freeable(void) 853 { 854 /* 855 * Wait until kthreadd is all set-up. 856 */ 857 wait_for_completion(&kthreadd_done); 858 859 /* Now the scheduler is fully set up and can do blocking allocations */ 860 gfp_allowed_mask = __GFP_BITS_MASK; 861 862 /* 863 * init can allocate pages on any node 864 */ 865 set_mems_allowed(node_states[N_MEMORY]); 866 /* 867 * init can run on any cpu. 868 */ 869 set_cpus_allowed_ptr(current, cpu_all_mask); 870 871 cad_pid = task_pid(current); 872 873 smp_prepare_cpus(setup_max_cpus); 874 875 do_pre_smp_initcalls(); 876 lockup_detector_init(); 877 878 smp_init(); 879 sched_init_smp(); 880 881 do_basic_setup(); 882 883 /* Open the /dev/console on the rootfs, this should never fail */ 884 if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0) 885 pr_err("Warning: unable to open an initial console.\n"); 886 887 (void) sys_dup(0); 888 (void) sys_dup(0); 889 /* 890 * check if there is an early userspace init. If yes, let it do all 891 * the work 892 */ 893 894 if (!ramdisk_execute_command) 895 ramdisk_execute_command = "/init"; 896 897 if (sys_access((const char __user *) ramdisk_execute_command, 0) != 0) { 898 ramdisk_execute_command = NULL; 899 prepare_namespace(); 900 } 901 902 /* 903 * Ok, we have completed the initial bootup, and 904 * we're essentially up and running. Get rid of the 905 * initmem segments and start the user-mode stuff.. 906 */ 907 908 /* rootfs is available now, try loading default modules */ 909 load_default_modules(); 910 } 911