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 <[email protected]> 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_ext.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 #include <linux/context_tracking.h> 79 #include <linux/random.h> 80 #include <linux/list.h> 81 #include <linux/integrity.h> 82 #include <linux/proc_ns.h> 83 #include <linux/io.h> 84 85 #include <asm/io.h> 86 #include <asm/bugs.h> 87 #include <asm/setup.h> 88 #include <asm/sections.h> 89 #include <asm/cacheflush.h> 90 91 static int kernel_init(void *); 92 93 extern void init_IRQ(void); 94 extern void fork_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 /* 101 * Debug helper: via this flag we know that we are in 'early bootup code' 102 * where only the boot processor is running with IRQ disabled. This means 103 * two things - IRQ must not be enabled before the flag is cleared and some 104 * operations which are not allowed with IRQ disabled are allowed while the 105 * flag is set. 106 */ 107 bool early_boot_irqs_disabled __read_mostly; 108 109 enum system_states system_state __read_mostly; 110 EXPORT_SYMBOL(system_state); 111 112 /* 113 * Boot command-line arguments 114 */ 115 #define MAX_INIT_ARGS CONFIG_INIT_ENV_ARG_LIMIT 116 #define MAX_INIT_ENVS CONFIG_INIT_ENV_ARG_LIMIT 117 118 extern void time_init(void); 119 /* Default late time init is NULL. archs can override this later. */ 120 void (*__initdata late_time_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 /* Command line for per-initcall parameter parsing */ 129 static char *initcall_command_line; 130 131 static char *execute_command; 132 static char *ramdisk_execute_command; 133 134 /* 135 * Used to generate warnings if static_key manipulation functions are used 136 * before jump_label_init is called. 137 */ 138 bool static_key_initialized __read_mostly; 139 EXPORT_SYMBOL_GPL(static_key_initialized); 140 141 /* 142 * If set, this is an indication to the drivers that reset the underlying 143 * device before going ahead with the initialization otherwise driver might 144 * rely on the BIOS and skip the reset operation. 145 * 146 * This is useful if kernel is booting in an unreliable environment. 147 * For ex. kdump situation where previous kernel has crashed, BIOS has been 148 * skipped and devices will be in unknown state. 149 */ 150 unsigned int reset_devices; 151 EXPORT_SYMBOL(reset_devices); 152 153 static int __init set_reset_devices(char *str) 154 { 155 reset_devices = 1; 156 return 1; 157 } 158 159 __setup("reset_devices", set_reset_devices); 160 161 static const char *argv_init[MAX_INIT_ARGS+2] = { "init", NULL, }; 162 const char *envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, }; 163 static const char *panic_later, *panic_param; 164 165 extern const struct obs_kernel_param __setup_start[], __setup_end[]; 166 167 static int __init obsolete_checksetup(char *line) 168 { 169 const struct obs_kernel_param *p; 170 int had_early_param = 0; 171 172 p = __setup_start; 173 do { 174 int n = strlen(p->str); 175 if (parameqn(line, p->str, n)) { 176 if (p->early) { 177 /* Already done in parse_early_param? 178 * (Needs exact match on param part). 179 * Keep iterating, as we can have early 180 * params and __setups of same names 8( */ 181 if (line[n] == '\0' || line[n] == '=') 182 had_early_param = 1; 183 } else if (!p->setup_func) { 184 pr_warn("Parameter %s is obsolete, ignored\n", 185 p->str); 186 return 1; 187 } else if (p->setup_func(line + n)) 188 return 1; 189 } 190 p++; 191 } while (p < __setup_end); 192 193 return had_early_param; 194 } 195 196 /* 197 * This should be approx 2 Bo*oMips to start (note initial shift), and will 198 * still work even if initially too large, it will just take slightly longer 199 */ 200 unsigned long loops_per_jiffy = (1<<12); 201 EXPORT_SYMBOL(loops_per_jiffy); 202 203 static int __init debug_kernel(char *str) 204 { 205 console_loglevel = CONSOLE_LOGLEVEL_DEBUG; 206 return 0; 207 } 208 209 static int __init quiet_kernel(char *str) 210 { 211 console_loglevel = CONSOLE_LOGLEVEL_QUIET; 212 return 0; 213 } 214 215 early_param("debug", debug_kernel); 216 early_param("quiet", quiet_kernel); 217 218 static int __init loglevel(char *str) 219 { 220 int newlevel; 221 222 /* 223 * Only update loglevel value when a correct setting was passed, 224 * to prevent blind crashes (when loglevel being set to 0) that 225 * are quite hard to debug 226 */ 227 if (get_option(&str, &newlevel)) { 228 console_loglevel = newlevel; 229 return 0; 230 } 231 232 return -EINVAL; 233 } 234 235 early_param("loglevel", loglevel); 236 237 /* Change NUL term back to "=", to make "param" the whole string. */ 238 static int __init repair_env_string(char *param, char *val, const char *unused) 239 { 240 if (val) { 241 /* param=val or param="val"? */ 242 if (val == param+strlen(param)+1) 243 val[-1] = '='; 244 else if (val == param+strlen(param)+2) { 245 val[-2] = '='; 246 memmove(val-1, val, strlen(val)+1); 247 val--; 248 } else 249 BUG(); 250 } 251 return 0; 252 } 253 254 /* Anything after -- gets handed straight to init. */ 255 static int __init set_init_arg(char *param, char *val, const char *unused) 256 { 257 unsigned int i; 258 259 if (panic_later) 260 return 0; 261 262 repair_env_string(param, val, unused); 263 264 for (i = 0; argv_init[i]; i++) { 265 if (i == MAX_INIT_ARGS) { 266 panic_later = "init"; 267 panic_param = param; 268 return 0; 269 } 270 } 271 argv_init[i] = param; 272 return 0; 273 } 274 275 /* 276 * Unknown boot options get handed to init, unless they look like 277 * unused parameters (modprobe will find them in /proc/cmdline). 278 */ 279 static int __init unknown_bootoption(char *param, char *val, const char *unused) 280 { 281 repair_env_string(param, val, unused); 282 283 /* Handle obsolete-style parameters */ 284 if (obsolete_checksetup(param)) 285 return 0; 286 287 /* Unused module parameter. */ 288 if (strchr(param, '.') && (!val || strchr(param, '.') < val)) 289 return 0; 290 291 if (panic_later) 292 return 0; 293 294 if (val) { 295 /* Environment option */ 296 unsigned int i; 297 for (i = 0; envp_init[i]; i++) { 298 if (i == MAX_INIT_ENVS) { 299 panic_later = "env"; 300 panic_param = param; 301 } 302 if (!strncmp(param, envp_init[i], val - param)) 303 break; 304 } 305 envp_init[i] = param; 306 } else { 307 /* Command line option */ 308 unsigned int i; 309 for (i = 0; argv_init[i]; i++) { 310 if (i == MAX_INIT_ARGS) { 311 panic_later = "init"; 312 panic_param = param; 313 } 314 } 315 argv_init[i] = param; 316 } 317 return 0; 318 } 319 320 static int __init init_setup(char *str) 321 { 322 unsigned int i; 323 324 execute_command = str; 325 /* 326 * In case LILO is going to boot us with default command line, 327 * it prepends "auto" before the whole cmdline which makes 328 * the shell think it should execute a script with such name. 329 * So we ignore all arguments entered _before_ init=... [MJ] 330 */ 331 for (i = 1; i < MAX_INIT_ARGS; i++) 332 argv_init[i] = NULL; 333 return 1; 334 } 335 __setup("init=", init_setup); 336 337 static int __init rdinit_setup(char *str) 338 { 339 unsigned int i; 340 341 ramdisk_execute_command = str; 342 /* See "auto" comment in init_setup */ 343 for (i = 1; i < MAX_INIT_ARGS; i++) 344 argv_init[i] = NULL; 345 return 1; 346 } 347 __setup("rdinit=", rdinit_setup); 348 349 #ifndef CONFIG_SMP 350 static const unsigned int setup_max_cpus = NR_CPUS; 351 static inline void setup_nr_cpu_ids(void) { } 352 static inline void smp_prepare_cpus(unsigned int maxcpus) { } 353 #endif 354 355 /* 356 * We need to store the untouched command line for future reference. 357 * We also need to store the touched command line since the parameter 358 * parsing is performed in place, and we should allow a component to 359 * store reference of name/value for future reference. 360 */ 361 static void __init setup_command_line(char *command_line) 362 { 363 saved_command_line = 364 memblock_virt_alloc(strlen(boot_command_line) + 1, 0); 365 initcall_command_line = 366 memblock_virt_alloc(strlen(boot_command_line) + 1, 0); 367 static_command_line = memblock_virt_alloc(strlen(command_line) + 1, 0); 368 strcpy(saved_command_line, boot_command_line); 369 strcpy(static_command_line, command_line); 370 } 371 372 /* 373 * We need to finalize in a non-__init function or else race conditions 374 * between the root thread and the init thread may cause start_kernel to 375 * be reaped by free_initmem before the root thread has proceeded to 376 * cpu_idle. 377 * 378 * gcc-3.4 accidentally inlines this function, so use noinline. 379 */ 380 381 static __initdata DECLARE_COMPLETION(kthreadd_done); 382 383 static noinline void __init_refok rest_init(void) 384 { 385 int pid; 386 387 rcu_scheduler_starting(); 388 smpboot_thread_init(); 389 /* 390 * We need to spawn init first so that it obtains pid 1, however 391 * the init task will end up wanting to create kthreads, which, if 392 * we schedule it before we create kthreadd, will OOPS. 393 */ 394 kernel_thread(kernel_init, NULL, CLONE_FS); 395 numa_default_policy(); 396 pid = kernel_thread(kthreadd, NULL, CLONE_FS | CLONE_FILES); 397 rcu_read_lock(); 398 kthreadd_task = find_task_by_pid_ns(pid, &init_pid_ns); 399 rcu_read_unlock(); 400 complete(&kthreadd_done); 401 402 /* 403 * The boot idle thread must execute schedule() 404 * at least once to get things moving: 405 */ 406 init_idle_bootup_task(current); 407 schedule_preempt_disabled(); 408 /* Call into cpu_idle with preempt disabled */ 409 cpu_startup_entry(CPUHP_ONLINE); 410 } 411 412 /* Check for early params. */ 413 static int __init do_early_param(char *param, char *val, const char *unused) 414 { 415 const struct obs_kernel_param *p; 416 417 for (p = __setup_start; p < __setup_end; p++) { 418 if ((p->early && parameq(param, p->str)) || 419 (strcmp(param, "console") == 0 && 420 strcmp(p->str, "earlycon") == 0) 421 ) { 422 if (p->setup_func(val) != 0) 423 pr_warn("Malformed early option '%s'\n", param); 424 } 425 } 426 /* We accept everything at this stage. */ 427 return 0; 428 } 429 430 void __init parse_early_options(char *cmdline) 431 { 432 parse_args("early options", cmdline, NULL, 0, 0, 0, do_early_param); 433 } 434 435 /* Arch code calls this early on, or if not, just before other parsing. */ 436 void __init parse_early_param(void) 437 { 438 static int done __initdata; 439 static char tmp_cmdline[COMMAND_LINE_SIZE] __initdata; 440 441 if (done) 442 return; 443 444 /* All fall through to do_early_param. */ 445 strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE); 446 parse_early_options(tmp_cmdline); 447 done = 1; 448 } 449 450 /* 451 * Activate the first processor. 452 */ 453 454 static void __init boot_cpu_init(void) 455 { 456 int cpu = smp_processor_id(); 457 /* Mark the boot cpu "present", "online" etc for SMP and UP case */ 458 set_cpu_online(cpu, true); 459 set_cpu_active(cpu, true); 460 set_cpu_present(cpu, true); 461 set_cpu_possible(cpu, true); 462 } 463 464 void __init __weak smp_setup_processor_id(void) 465 { 466 } 467 468 # if THREAD_SIZE >= PAGE_SIZE 469 void __init __weak thread_info_cache_init(void) 470 { 471 } 472 #endif 473 474 /* 475 * Set up kernel memory allocators 476 */ 477 static void __init mm_init(void) 478 { 479 /* 480 * page_ext requires contiguous pages, 481 * bigger than MAX_ORDER unless SPARSEMEM. 482 */ 483 page_ext_init_flatmem(); 484 mem_init(); 485 kmem_cache_init(); 486 percpu_init_late(); 487 pgtable_init(); 488 vmalloc_init(); 489 ioremap_huge_init(); 490 } 491 492 asmlinkage __visible void __init start_kernel(void) 493 { 494 char *command_line; 495 char *after_dashes; 496 497 /* 498 * Need to run as early as possible, to initialize the 499 * lockdep hash: 500 */ 501 lockdep_init(); 502 set_task_stack_end_magic(&init_task); 503 smp_setup_processor_id(); 504 debug_objects_early_init(); 505 506 /* 507 * Set up the the initial canary ASAP: 508 */ 509 boot_init_stack_canary(); 510 511 cgroup_init_early(); 512 513 local_irq_disable(); 514 early_boot_irqs_disabled = true; 515 516 /* 517 * Interrupts are still disabled. Do necessary setups, then 518 * enable them 519 */ 520 boot_cpu_init(); 521 page_address_init(); 522 pr_notice("%s", linux_banner); 523 setup_arch(&command_line); 524 mm_init_cpumask(&init_mm); 525 setup_command_line(command_line); 526 setup_nr_cpu_ids(); 527 setup_per_cpu_areas(); 528 smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */ 529 530 build_all_zonelists(NULL, NULL); 531 page_alloc_init(); 532 533 pr_notice("Kernel command line: %s\n", boot_command_line); 534 parse_early_param(); 535 after_dashes = parse_args("Booting kernel", 536 static_command_line, __start___param, 537 __stop___param - __start___param, 538 -1, -1, &unknown_bootoption); 539 if (!IS_ERR_OR_NULL(after_dashes)) 540 parse_args("Setting init args", after_dashes, NULL, 0, -1, -1, 541 set_init_arg); 542 543 jump_label_init(); 544 545 /* 546 * These use large bootmem allocations and must precede 547 * kmem_cache_init() 548 */ 549 setup_log_buf(0); 550 pidhash_init(); 551 vfs_caches_init_early(); 552 sort_main_extable(); 553 trap_init(); 554 mm_init(); 555 556 /* 557 * Set up the scheduler prior starting any interrupts (such as the 558 * timer interrupt). Full topology setup happens at smp_init() 559 * time - but meanwhile we still have a functioning scheduler. 560 */ 561 sched_init(); 562 /* 563 * Disable preemption - early bootup scheduling is extremely 564 * fragile until we cpu_idle() for the first time. 565 */ 566 preempt_disable(); 567 if (WARN(!irqs_disabled(), 568 "Interrupts were enabled *very* early, fixing it\n")) 569 local_irq_disable(); 570 idr_init_cache(); 571 rcu_init(); 572 573 /* trace_printk() and trace points may be used after this */ 574 trace_init(); 575 576 context_tracking_init(); 577 radix_tree_init(); 578 /* init some links before init_ISA_irqs() */ 579 early_irq_init(); 580 init_IRQ(); 581 tick_init(); 582 rcu_init_nohz(); 583 init_timers(); 584 hrtimers_init(); 585 softirq_init(); 586 timekeeping_init(); 587 time_init(); 588 sched_clock_postinit(); 589 perf_event_init(); 590 profile_init(); 591 call_function_init(); 592 WARN(!irqs_disabled(), "Interrupts were enabled early\n"); 593 early_boot_irqs_disabled = false; 594 local_irq_enable(); 595 596 kmem_cache_init_late(); 597 598 /* 599 * HACK ALERT! This is early. We're enabling the console before 600 * we've done PCI setups etc, and console_init() must be aware of 601 * this. But we do want output early, in case something goes wrong. 602 */ 603 console_init(); 604 if (panic_later) 605 panic("Too many boot %s vars at `%s'", panic_later, 606 panic_param); 607 608 lockdep_info(); 609 610 /* 611 * Need to run this when irqs are enabled, because it wants 612 * to self-test [hard/soft]-irqs on/off lock inversion bugs 613 * too: 614 */ 615 locking_selftest(); 616 617 #ifdef CONFIG_BLK_DEV_INITRD 618 if (initrd_start && !initrd_below_start_ok && 619 page_to_pfn(virt_to_page((void *)initrd_start)) < min_low_pfn) { 620 pr_crit("initrd overwritten (0x%08lx < 0x%08lx) - disabling it.\n", 621 page_to_pfn(virt_to_page((void *)initrd_start)), 622 min_low_pfn); 623 initrd_start = 0; 624 } 625 #endif 626 page_ext_init(); 627 debug_objects_mem_init(); 628 kmemleak_init(); 629 setup_per_cpu_pageset(); 630 numa_policy_init(); 631 if (late_time_init) 632 late_time_init(); 633 sched_clock_init(); 634 calibrate_delay(); 635 pidmap_init(); 636 anon_vma_init(); 637 acpi_early_init(); 638 #ifdef CONFIG_X86 639 if (efi_enabled(EFI_RUNTIME_SERVICES)) 640 efi_enter_virtual_mode(); 641 #endif 642 #ifdef CONFIG_X86_ESPFIX64 643 /* Should be run before the first non-init thread is created */ 644 init_espfix_bsp(); 645 #endif 646 thread_info_cache_init(); 647 cred_init(); 648 fork_init(); 649 proc_caches_init(); 650 buffer_init(); 651 key_init(); 652 security_init(); 653 dbg_late_init(); 654 vfs_caches_init(totalram_pages); 655 signals_init(); 656 /* rootfs populating might need page-writeback */ 657 page_writeback_init(); 658 proc_root_init(); 659 nsfs_init(); 660 cpuset_init(); 661 cgroup_init(); 662 taskstats_init_early(); 663 delayacct_init(); 664 665 check_bugs(); 666 667 acpi_subsystem_init(); 668 sfi_init_late(); 669 670 if (efi_enabled(EFI_RUNTIME_SERVICES)) { 671 efi_late_init(); 672 efi_free_boot_services(); 673 } 674 675 ftrace_init(); 676 677 /* Do the rest non-__init'ed, we're now alive */ 678 rest_init(); 679 } 680 681 /* Call all constructor functions linked into the kernel. */ 682 static void __init do_ctors(void) 683 { 684 #ifdef CONFIG_CONSTRUCTORS 685 ctor_fn_t *fn = (ctor_fn_t *) __ctors_start; 686 687 for (; fn < (ctor_fn_t *) __ctors_end; fn++) 688 (*fn)(); 689 #endif 690 } 691 692 bool initcall_debug; 693 core_param(initcall_debug, initcall_debug, bool, 0644); 694 695 #ifdef CONFIG_KALLSYMS 696 struct blacklist_entry { 697 struct list_head next; 698 char *buf; 699 }; 700 701 static __initdata_or_module LIST_HEAD(blacklisted_initcalls); 702 703 static int __init initcall_blacklist(char *str) 704 { 705 char *str_entry; 706 struct blacklist_entry *entry; 707 708 /* str argument is a comma-separated list of functions */ 709 do { 710 str_entry = strsep(&str, ","); 711 if (str_entry) { 712 pr_debug("blacklisting initcall %s\n", str_entry); 713 entry = alloc_bootmem(sizeof(*entry)); 714 entry->buf = alloc_bootmem(strlen(str_entry) + 1); 715 strcpy(entry->buf, str_entry); 716 list_add(&entry->next, &blacklisted_initcalls); 717 } 718 } while (str_entry); 719 720 return 0; 721 } 722 723 static bool __init_or_module initcall_blacklisted(initcall_t fn) 724 { 725 struct list_head *tmp; 726 struct blacklist_entry *entry; 727 char *fn_name; 728 729 fn_name = kasprintf(GFP_KERNEL, "%pf", fn); 730 if (!fn_name) 731 return false; 732 733 list_for_each(tmp, &blacklisted_initcalls) { 734 entry = list_entry(tmp, struct blacklist_entry, next); 735 if (!strcmp(fn_name, entry->buf)) { 736 pr_debug("initcall %s blacklisted\n", fn_name); 737 kfree(fn_name); 738 return true; 739 } 740 } 741 742 kfree(fn_name); 743 return false; 744 } 745 #else 746 static int __init initcall_blacklist(char *str) 747 { 748 pr_warn("initcall_blacklist requires CONFIG_KALLSYMS\n"); 749 return 0; 750 } 751 752 static bool __init_or_module initcall_blacklisted(initcall_t fn) 753 { 754 return false; 755 } 756 #endif 757 __setup("initcall_blacklist=", initcall_blacklist); 758 759 static int __init_or_module do_one_initcall_debug(initcall_t fn) 760 { 761 ktime_t calltime, delta, rettime; 762 unsigned long long duration; 763 int ret; 764 765 printk(KERN_DEBUG "calling %pF @ %i\n", fn, task_pid_nr(current)); 766 calltime = ktime_get(); 767 ret = fn(); 768 rettime = ktime_get(); 769 delta = ktime_sub(rettime, calltime); 770 duration = (unsigned long long) ktime_to_ns(delta) >> 10; 771 printk(KERN_DEBUG "initcall %pF returned %d after %lld usecs\n", 772 fn, ret, duration); 773 774 return ret; 775 } 776 777 int __init_or_module do_one_initcall(initcall_t fn) 778 { 779 int count = preempt_count(); 780 int ret; 781 char msgbuf[64]; 782 783 if (initcall_blacklisted(fn)) 784 return -EPERM; 785 786 if (initcall_debug) 787 ret = do_one_initcall_debug(fn); 788 else 789 ret = fn(); 790 791 msgbuf[0] = 0; 792 793 if (preempt_count() != count) { 794 sprintf(msgbuf, "preemption imbalance "); 795 preempt_count_set(count); 796 } 797 if (irqs_disabled()) { 798 strlcat(msgbuf, "disabled interrupts ", sizeof(msgbuf)); 799 local_irq_enable(); 800 } 801 WARN(msgbuf[0], "initcall %pF returned with %s\n", fn, msgbuf); 802 803 return ret; 804 } 805 806 807 extern initcall_t __initcall_start[]; 808 extern initcall_t __initcall0_start[]; 809 extern initcall_t __initcall1_start[]; 810 extern initcall_t __initcall2_start[]; 811 extern initcall_t __initcall3_start[]; 812 extern initcall_t __initcall4_start[]; 813 extern initcall_t __initcall5_start[]; 814 extern initcall_t __initcall6_start[]; 815 extern initcall_t __initcall7_start[]; 816 extern initcall_t __initcall_end[]; 817 818 static initcall_t *initcall_levels[] __initdata = { 819 __initcall0_start, 820 __initcall1_start, 821 __initcall2_start, 822 __initcall3_start, 823 __initcall4_start, 824 __initcall5_start, 825 __initcall6_start, 826 __initcall7_start, 827 __initcall_end, 828 }; 829 830 /* Keep these in sync with initcalls in include/linux/init.h */ 831 static char *initcall_level_names[] __initdata = { 832 "early", 833 "core", 834 "postcore", 835 "arch", 836 "subsys", 837 "fs", 838 "device", 839 "late", 840 }; 841 842 static void __init do_initcall_level(int level) 843 { 844 initcall_t *fn; 845 846 strcpy(initcall_command_line, saved_command_line); 847 parse_args(initcall_level_names[level], 848 initcall_command_line, __start___param, 849 __stop___param - __start___param, 850 level, level, 851 &repair_env_string); 852 853 for (fn = initcall_levels[level]; fn < initcall_levels[level+1]; fn++) 854 do_one_initcall(*fn); 855 } 856 857 static void __init do_initcalls(void) 858 { 859 int level; 860 861 for (level = 0; level < ARRAY_SIZE(initcall_levels) - 1; level++) 862 do_initcall_level(level); 863 } 864 865 /* 866 * Ok, the machine is now initialized. None of the devices 867 * have been touched yet, but the CPU subsystem is up and 868 * running, and memory and process management works. 869 * 870 * Now we can finally start doing some real work.. 871 */ 872 static void __init do_basic_setup(void) 873 { 874 cpuset_init_smp(); 875 usermodehelper_init(); 876 shmem_init(); 877 driver_init(); 878 init_irq_proc(); 879 do_ctors(); 880 usermodehelper_enable(); 881 do_initcalls(); 882 random_int_secret_init(); 883 } 884 885 static void __init do_pre_smp_initcalls(void) 886 { 887 initcall_t *fn; 888 889 for (fn = __initcall_start; fn < __initcall0_start; fn++) 890 do_one_initcall(*fn); 891 } 892 893 /* 894 * This function requests modules which should be loaded by default and is 895 * called twice right after initrd is mounted and right before init is 896 * exec'd. If such modules are on either initrd or rootfs, they will be 897 * loaded before control is passed to userland. 898 */ 899 void __init load_default_modules(void) 900 { 901 load_default_elevator_module(); 902 } 903 904 static int run_init_process(const char *init_filename) 905 { 906 argv_init[0] = init_filename; 907 return do_execve(getname_kernel(init_filename), 908 (const char __user *const __user *)argv_init, 909 (const char __user *const __user *)envp_init); 910 } 911 912 static int try_to_run_init_process(const char *init_filename) 913 { 914 int ret; 915 916 ret = run_init_process(init_filename); 917 918 if (ret && ret != -ENOENT) { 919 pr_err("Starting init: %s exists but couldn't execute it (error %d)\n", 920 init_filename, ret); 921 } 922 923 return ret; 924 } 925 926 static noinline void __init kernel_init_freeable(void); 927 928 static int __ref kernel_init(void *unused) 929 { 930 int ret; 931 932 kernel_init_freeable(); 933 /* need to finish all async __init code before freeing the memory */ 934 async_synchronize_full(); 935 free_initmem(); 936 mark_rodata_ro(); 937 system_state = SYSTEM_RUNNING; 938 numa_default_policy(); 939 940 flush_delayed_fput(); 941 942 if (ramdisk_execute_command) { 943 ret = run_init_process(ramdisk_execute_command); 944 if (!ret) 945 return 0; 946 pr_err("Failed to execute %s (error %d)\n", 947 ramdisk_execute_command, ret); 948 } 949 950 /* 951 * We try each of these until one succeeds. 952 * 953 * The Bourne shell can be used instead of init if we are 954 * trying to recover a really broken machine. 955 */ 956 if (execute_command) { 957 ret = run_init_process(execute_command); 958 if (!ret) 959 return 0; 960 panic("Requested init %s failed (error %d).", 961 execute_command, ret); 962 } 963 if (!try_to_run_init_process("/sbin/init") || 964 !try_to_run_init_process("/etc/init") || 965 !try_to_run_init_process("/bin/init") || 966 !try_to_run_init_process("/bin/sh")) 967 return 0; 968 969 panic("No working init found. Try passing init= option to kernel. " 970 "See Linux Documentation/init.txt for guidance."); 971 } 972 973 static noinline void __init kernel_init_freeable(void) 974 { 975 /* 976 * Wait until kthreadd is all set-up. 977 */ 978 wait_for_completion(&kthreadd_done); 979 980 /* Now the scheduler is fully set up and can do blocking allocations */ 981 gfp_allowed_mask = __GFP_BITS_MASK; 982 983 /* 984 * init can allocate pages on any node 985 */ 986 set_mems_allowed(node_states[N_MEMORY]); 987 /* 988 * init can run on any cpu. 989 */ 990 set_cpus_allowed_ptr(current, cpu_all_mask); 991 992 cad_pid = task_pid(current); 993 994 smp_prepare_cpus(setup_max_cpus); 995 996 do_pre_smp_initcalls(); 997 lockup_detector_init(); 998 999 smp_init(); 1000 sched_init_smp(); 1001 1002 do_basic_setup(); 1003 1004 /* Open the /dev/console on the rootfs, this should never fail */ 1005 if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0) 1006 pr_err("Warning: unable to open an initial console.\n"); 1007 1008 (void) sys_dup(0); 1009 (void) sys_dup(0); 1010 /* 1011 * check if there is an early userspace init. If yes, let it do all 1012 * the work 1013 */ 1014 1015 if (!ramdisk_execute_command) 1016 ramdisk_execute_command = "/init"; 1017 1018 if (sys_access((const char __user *) ramdisk_execute_command, 0) != 0) { 1019 ramdisk_execute_command = NULL; 1020 prepare_namespace(); 1021 } 1022 1023 /* 1024 * Ok, we have completed the initial bootup, and 1025 * we're essentially up and running. Get rid of the 1026 * initmem segments and start the user-mode stuff.. 1027 * 1028 * rootfs is available now, try loading the public keys 1029 * and default modules 1030 */ 1031 1032 integrity_load_keys(); 1033 load_default_modules(); 1034 }
标签：__,Kernel,include,void,init,static,initcall,main From： https://www.cnblogs.com/kunshanpipixia/p/17779781.html