init/main.c

   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_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/pagemap.h>
  63 #include <linux/sched.h>
  64 #include <linux/signal.h>
  65 #include <linux/idr.h>
  66 #include <linux/kgdb.h>
  67 #include <linux/ftrace.h>
  68 #include <linux/async.h>
  69 #include <linux/kmemcheck.h>
  70 #include <linux/sfi.h>
  71 #include <linux/shmem_fs.h>
  72 #include <linux/slab.h>
  73 #include <linux/perf_event.h>
  74 #include <linux/file.h>
  75 #include <linux/ptrace.h>
  76 #include <linux/blkdev.h>
  77 #include <linux/elevator.h>
  78 #include <linux/sched_clock.h>
  79 #include <linux/context_tracking.h>
  80 #include <linux/random.h>
  81 #include <linux/list.h>
  82 #include <linux/integrity.h>
  83 #include <linux/proc_ns.h>
  84 #include <linux/io.h>
  85
  86 #include <asm/io.h>
  87 #include <asm/bugs.h>
  88 #include <asm/setup.h>
  89 #include <asm/sections.h>
  90 #include <asm/cacheflush.h>
  91
  92 static int kernel_init(void *);
  93
  94 extern void init_IRQ(void);
  95 extern void fork_init(void);
  96 extern void radix_tree_init(void);
  97
  98 /*
  99  * Debug helper: via this flag we know that we are in 'early bootup code'
 100  * where only the boot processor is running with IRQ disabled.  This means
 101  * two things - IRQ must not be enabled before the flag is cleared and some
 102  * operations which are not allowed with IRQ disabled are allowed while the
 103  * flag is set.
 104  */
 105 bool early_boot_irqs_disabled __read_mostly;
 106
 107 enum system_states system_state __read_mostly;
 108 EXPORT_SYMBOL(system_state);
 109
 110 /*
 111  * Boot command-line arguments
 112  */
 113 #define MAX_INIT_ARGS CONFIG_INIT_ENV_ARG_LIMIT
 114 #define MAX_INIT_ENVS CONFIG_INIT_ENV_ARG_LIMIT
 115
 116 extern void time_init(void);
 117 /* Default late time init is NULL. archs can override this later. */
 118 void (*__initdata late_time_init)(void);
 119
 120 /* Untouched command line saved by arch-specific code. */
 121 char __initdata boot_command_line[COMMAND_LINE_SIZE];
 122 /* Untouched saved command line (eg. for /proc) */
 123 char *saved_command_line;
 124 /* Command line for parameter parsing */
 125 static char *static_command_line;
 126 /* Command line for per-initcall parameter parsing */
 127 static char *initcall_command_line;
 128
 129 static char *execute_command;
 130 static char *ramdisk_execute_command;
 131
 132 /*
 133  * Used to generate warnings if static_key manipulation functions are used
 134  * before jump_label_init is called.
 135  */
 136 bool static_key_initialized __read_mostly;
 137 EXPORT_SYMBOL_GPL(static_key_initialized);
 138
 139 /*
 140  * If set, this is an indication to the drivers that reset the underlying
 141  * device before going ahead with the initialization otherwise driver might
 142  * rely on the BIOS and skip the reset operation.
 143  *
 144  * This is useful if kernel is booting in an unreliable environment.
 145  * For ex. kdump situation where previous kernel has crashed, BIOS has been
 146  * skipped and devices will be in unknown state.
 147  */
 148 unsigned int reset_devices;
 149 EXPORT_SYMBOL(reset_devices);
 150
 151 static int __init set_reset_devices(char *str)
 152 {
 153         reset_devices = 1;
 154         return 1;
 155 }
 156
 157 __setup("reset_devices", set_reset_devices);
 158
 159 static const char *argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
 160 const char *envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, };
 161 static const char *panic_later, *panic_param;
 162
 163 extern const struct obs_kernel_param __setup_start[], __setup_end[];
 164
 165 static bool __init obsolete_checksetup(char *line)
 166 {
 167         const struct obs_kernel_param *p;
 168         bool had_early_param = false;
 169
 170         p = __setup_start;
 171         do {
 172                 int n = strlen(p->str);
 173                 if (parameqn(line, p->str, n)) {
 174                         if (p->early) {
 175                                 /* Already done in parse_early_param?
 176                                  * (Needs exact match on param part).
 177                                  * Keep iterating, as we can have early
 178                                  * params and __setups of same names 8( */
 179                                 if (line[n] == '\0' || line[n] == '=')
 180                                         had_early_param = true;
 181                         } else if (!p->setup_func) {
 182                                 pr_warn("Parameter %s is obsolete, ignored\n",
 183                                         p->str);
 184                                 return true;
 185                         } else if (p->setup_func(line + n))
 186                                 return true;
 187                 }
 188                 p++;
 189         } while (p < __setup_end);
 190
 191         return had_early_param;
 192 }
 193
 194 /*
 195  * This should be approx 2 Bo*oMips to start (note initial shift), and will
 196  * still work even if initially too large, it will just take slightly longer
 197  */
 198 unsigned long loops_per_jiffy = (1<<12);
 199 EXPORT_SYMBOL(loops_per_jiffy);
 200
 201 static int __init debug_kernel(char *str)
 202 {
 203         console_loglevel = CONSOLE_LOGLEVEL_DEBUG;
 204         return 0;
 205 }
 206
 207 static int __init quiet_kernel(char *str)
 208 {
 209         console_loglevel = CONSOLE_LOGLEVEL_QUIET;
 210         return 0;
 211 }
 212
 213 early_param("debug", debug_kernel);
 214 early_param("quiet", quiet_kernel);
 215
 216 static int __init loglevel(char *str)
 217 {
 218         int newlevel;
 219
 220         /*
 221          * Only update loglevel value when a correct setting was passed,
 222          * to prevent blind crashes (when loglevel being set to 0) that
 223          * are quite hard to debug
 224          */
 225         if (get_option(&str, &newlevel)) {
 226                 console_loglevel = newlevel;
 227                 return 0;
 228         }
 229
 230         return -EINVAL;
 231 }
 232
 233 early_param("loglevel", loglevel);
 234
 235 /* Change NUL term back to "=", to make "param" the whole string. */
 236 static int __init repair_env_string(char *param, char *val,
 237                                     const char *unused, void *arg)
 238 {
 239         if (val) {
 240                 /* param=val or param="val"? */
 241                 if (val == param+strlen(param)+1)
 242                         val[-1] = '=';
 243                 else if (val == param+strlen(param)+2) {
 244                         val[-2] = '=';
 245                         memmove(val-1, val, strlen(val)+1);
 246                         val--;
 247                 } else
 248                         BUG();
 249         }
 250         return 0;
 251 }
 252
 253 /* Anything after -- gets handed straight to init. */
 254 static int __init set_init_arg(char *param, char *val,
 255                                const char *unused, void *arg)
 256 {
 257         unsigned int i;
 258
 259         if (panic_later)
 260                 return 0;
 261
 262         repair_env_string(param, val, unused, NULL);
 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,
 280                                      const char *unused, void *arg)
 281 {
 282         repair_env_string(param, val, unused, NULL);
 283
 284         /* Handle obsolete-style parameters */
 285         if (obsolete_checksetup(param))
 286                 return 0;
 287
 288         /* Unused module parameter. */
 289         if (strchr(param, '.') && (!val || strchr(param, '.') < val))
 290                 return 0;
 291
 292         if (panic_later)
 293                 return 0;
 294
 295         if (val) {
 296                 /* Environment option */
 297                 unsigned int i;
 298                 for (i = 0; envp_init[i]; i++) {
 299                         if (i == MAX_INIT_ENVS) {
 300                                 panic_later = "env";
 301                                 panic_param = param;
 302                         }
 303                         if (!strncmp(param, envp_init[i], val - param))
 304                                 break;
 305                 }
 306                 envp_init[i] = param;
 307         } else {
 308                 /* Command line option */
 309                 unsigned int i;
 310                 for (i = 0; argv_init[i]; i++) {
 311                         if (i == MAX_INIT_ARGS) {
 312                                 panic_later = "init";
 313                                 panic_param = param;
 314                         }
 315                 }
 316                 argv_init[i] = param;
 317         }
 318         return 0;
 319 }
 320
 321 static int __init init_setup(char *str)
 322 {
 323         unsigned int i;
 324
 325         execute_command = str;
 326         /*
 327          * In case LILO is going to boot us with default command line,
 328          * it prepends "auto" before the whole cmdline which makes
 329          * the shell think it should execute a script with such name.
 330          * So we ignore all arguments entered _before_ init=... [MJ]
 331          */
 332         for (i = 1; i < MAX_INIT_ARGS; i++)
 333                 argv_init[i] = NULL;
 334         return 1;
 335 }
 336 __setup("init=", init_setup);
 337
 338 static int __init rdinit_setup(char *str)
 339 {
 340         unsigned int i;
 341
 342         ramdisk_execute_command = str;
 343         /* See "auto" comment in init_setup */
 344         for (i = 1; i < MAX_INIT_ARGS; i++)
 345                 argv_init[i] = NULL;
 346         return 1;
 347 }
 348 __setup("rdinit=", rdinit_setup);
 349
 350 #ifndef CONFIG_SMP
 351 static const unsigned int setup_max_cpus = NR_CPUS;
 352 static inline void setup_nr_cpu_ids(void) { }
 353 static inline void smp_prepare_cpus(unsigned int maxcpus) { }
 354 #endif
 355
 356 /*
 357  * We need to store the untouched command line for future reference.
 358  * We also need to store the touched command line since the parameter
 359  * parsing is performed in place, and we should allow a component to
 360  * store reference of name/value for future reference.
 361  */
 362 static void __init setup_command_line(char *command_line)
 363 {
 364         saved_command_line =
 365                 memblock_virt_alloc(strlen(boot_command_line) + 1, 0);
 366         initcall_command_line =
 367                 memblock_virt_alloc(strlen(boot_command_line) + 1, 0);
 368         static_command_line = memblock_virt_alloc(strlen(command_line) + 1, 0);
 369         strcpy(saved_command_line, boot_command_line);
 370         strcpy(static_command_line, command_line);
 371 }
 372
 373 /*
 374  * We need to finalize in a non-__init function or else race conditions
 375  * between the root thread and the init thread may cause start_kernel to
 376  * be reaped by free_initmem before the root thread has proceeded to
 377  * cpu_idle.
 378  *
 379  * gcc-3.4 accidentally inlines this function, so use noinline.
 380  */
 381
 382 static __initdata DECLARE_COMPLETION(kthreadd_done);
 383
 384 static noinline void __ref rest_init(void)
 385 {
 386         int pid;
 387
 388         rcu_scheduler_starting();
 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,
 414                                  const char *unused, void *arg)
 415 {
 416         const struct obs_kernel_param *p;
 417
 418         for (p = __setup_start; p < __setup_end; p++) {
 419                 if ((p->early && parameq(param, p->str)) ||
 420                     (strcmp(param, "console") == 0 &&
 421                      strcmp(p->str, "earlycon") == 0)
 422                 ) {
 423                         if (p->setup_func(val) != 0)
 424                                 pr_warn("Malformed early option '%s'\n", param);
 425                 }
 426         }
 427         /* We accept everything at this stage. */
 428         return 0;
 429 }
 430
 431 void __init parse_early_options(char *cmdline)
 432 {
 433         parse_args("early options", cmdline, NULL, 0, 0, 0, NULL,
 434                    do_early_param);
 435 }
 436
 437 /* Arch code calls this early on, or if not, just before other parsing. */
 438 void __init parse_early_param(void)
 439 {
 440         static int done __initdata;
 441         static char tmp_cmdline[COMMAND_LINE_SIZE] __initdata;
 442
 443         if (done)
 444                 return;
 445
 446         /* All fall through to do_early_param. */
 447         strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);
 448         parse_early_options(tmp_cmdline);
 449         done = 1;
 450 }
 451
 452 void __init __weak smp_setup_processor_id(void)
 453 {
 454 }
 455
 456 # if THREAD_SIZE >= PAGE_SIZE
 457 void __init __weak thread_stack_cache_init(void)
 458 {
 459 }
 460 #endif
 461
 462 /*
 463  * Set up kernel memory allocators
 464  */
 465 static void __init mm_init(void)
 466 {
 467         /* Does address_space.flags still fit into a 32-bit ulong? */
 468         BUILD_BUG_ON(AS_LAST_FLAG > 32);
 469
 470         /*
 471          * page_ext requires contiguous pages,
 472          * bigger than MAX_ORDER unless SPARSEMEM.
 473          */
 474         page_ext_init_flatmem();
 475         mem_init();
 476         kmem_cache_init();
 477         percpu_init_late();
 478         pgtable_init();
 479         vmalloc_init();
 480         ioremap_huge_init();
 481 }
 482
 483 asmlinkage __visible void __init start_kernel(void)
 484 {
 485         char *command_line;
 486         char *after_dashes;
 487
 488         set_task_stack_end_magic(&init_task);
 489         smp_setup_processor_id();
 490         debug_objects_early_init();
 491
 492         /*
 493          * Set up the the initial canary ASAP:
 494          */
 495         boot_init_stack_canary();
 496
 497         cgroup_init_early();
 498
 499         local_irq_disable();
 500         early_boot_irqs_disabled = true;
 501
 502 /*
 503  * Interrupts are still disabled. Do necessary setups, then
 504  * enable them
 505  */
 506         boot_cpu_init();
 507         page_address_init();
 508         pr_notice("%s", linux_banner);
 509         setup_arch(&command_line);
 510         mm_init_cpumask(&init_mm);
 511         setup_command_line(command_line);
 512         setup_nr_cpu_ids();
 513         setup_per_cpu_areas();
 514         boot_cpu_state_init();
 515         smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */
 516
 517         build_all_zonelists(NULL, NULL);
 518         page_alloc_init();
 519
 520         pr_notice("Kernel command line: %s\n", boot_command_line);
 521         parse_early_param();
 522         after_dashes = parse_args("Booting kernel",
 523                                   static_command_line, __start___param,
 524                                   __stop___param - __start___param,
 525                                   -1, -1, NULL, &unknown_bootoption);
 526         if (!IS_ERR_OR_NULL(after_dashes))
 527                 parse_args("Setting init args", after_dashes, NULL, 0, -1, -1,
 528                            NULL, set_init_arg);
 529
 530         jump_label_init();
 531
 532         /*
 533          * These use large bootmem allocations and must precede
 534          * kmem_cache_init()
 535          */
 536         setup_log_buf(0);
 537         pidhash_init();
 538         vfs_caches_init_early();
 539         sort_main_extable();
 540         trap_init();
 541         mm_init();
 542
 543         /*
 544          * Set up the scheduler prior starting any interrupts (such as the
 545          * timer interrupt). Full topology setup happens at smp_init()
 546          * time - but meanwhile we still have a functioning scheduler.
 547          */
 548         sched_init();
 549         /*
 550          * Disable preemption - early bootup scheduling is extremely
 551          * fragile until we cpu_idle() for the first time.
 552          */
 553         preempt_disable();
 554         if (WARN(!irqs_disabled(),
 555                  "Interrupts were enabled *very* early, fixing it\n"))
 556                 local_irq_disable();
 557         idr_init_cache();
 558         rcu_init();
 559
 560         /* trace_printk() and trace points may be used after this */
 561         trace_init();
 562
 563         context_tracking_init();
 564         radix_tree_init();
 565         /* init some links before init_ISA_irqs() */
 566         early_irq_init();
 567         init_IRQ();
 568         tick_init();
 569         rcu_init_nohz();
 570         init_timers();
 571         hrtimers_init();
 572         softirq_init();
 573         timekeeping_init();
 574         time_init();
 575         sched_clock_postinit();
 576         printk_nmi_init();
 577         perf_event_init();
 578         profile_init();
 579         call_function_init();
 580         WARN(!irqs_disabled(), "Interrupts were enabled early\n");
 581         early_boot_irqs_disabled = false;
 582         local_irq_enable();
 583
 584         kmem_cache_init_late();
 585
 586         /*
 587          * HACK ALERT! This is early. We're enabling the console before
 588          * we've done PCI setups etc, and console_init() must be aware of
 589          * this. But we do want output early, in case something goes wrong.
 590          */
 591         console_init();
 592         if (panic_later)
 593                 panic("Too many boot %s vars at `%s'", panic_later,
 594                       panic_param);
 595
 596         lockdep_info();
 597
 598         /*
 599          * Need to run this when irqs are enabled, because it wants
 600          * to self-test [hard/soft]-irqs on/off lock inversion bugs
 601          * too:
 602          */
 603         locking_selftest();
 604
 605 #ifdef CONFIG_BLK_DEV_INITRD
 606         if (initrd_start && !initrd_below_start_ok &&
 607             page_to_pfn(virt_to_page((void *)initrd_start)) < min_low_pfn) {
 608                 pr_crit("initrd overwritten (0x%08lx < 0x%08lx) - disabling it.\n",
 609                     page_to_pfn(virt_to_page((void *)initrd_start)),
 610                     min_low_pfn);
 611                 initrd_start = 0;
 612         }
 613 #endif
 614         page_ext_init();
 615         debug_objects_mem_init();
 616         kmemleak_init();
 617         setup_per_cpu_pageset();
 618         numa_policy_init();
 619         if (late_time_init)
 620                 late_time_init();
 621         sched_clock_init();
 622         calibrate_delay();
 623         pidmap_init();
 624         anon_vma_init();
 625         acpi_early_init();
 626 #ifdef CONFIG_X86
 627         if (efi_enabled(EFI_RUNTIME_SERVICES))
 628                 efi_enter_virtual_mode();
 629 #endif
 630 #ifdef CONFIG_X86_ESPFIX64
 631         /* Should be run before the first non-init thread is created */
 632         init_espfix_bsp();
 633 #endif
 634         thread_stack_cache_init();
 635         cred_init();
 636         fork_init();
 637         proc_caches_init();
 638         buffer_init();
 639         key_init();
 640         security_init();
 641         dbg_late_init();
 642         vfs_caches_init();
 643         signals_init();
 644         /* rootfs populating might need page-writeback */
 645         page_writeback_init();
 646         proc_root_init();
 647         nsfs_init();
 648         cpuset_init();
 649         cgroup_init();
 650         taskstats_init_early();
 651         delayacct_init();
 652
 653         check_bugs();
 654
 655         acpi_subsystem_init();
 656         sfi_init_late();
 657
 658         if (efi_enabled(EFI_RUNTIME_SERVICES)) {
 659                 efi_late_init();
 660                 efi_free_boot_services();
 661         }
 662
 663         ftrace_init();
 664
 665         /* Do the rest non-__init'ed, we're now alive */
 666         rest_init();
 667 }
 668
 669 /* Call all constructor functions linked into the kernel. */
 670 static void __init do_ctors(void)
 671 {
 672 #ifdef CONFIG_CONSTRUCTORS
 673         ctor_fn_t *fn = (ctor_fn_t *) __ctors_start;
 674
 675         for (; fn < (ctor_fn_t *) __ctors_end; fn++)
 676                 (*fn)();
 677 #endif
 678 }
 679
 680 bool initcall_debug;
 681 core_param(initcall_debug, initcall_debug, bool, 0644);
 682
 683 #ifdef CONFIG_KALLSYMS
 684 struct blacklist_entry {
 685         struct list_head next;
 686         char *buf;
 687 };
 688
 689 static __initdata_or_module LIST_HEAD(blacklisted_initcalls);
 690
 691 static int __init initcall_blacklist(char *str)
 692 {
 693         char *str_entry;
 694         struct blacklist_entry *entry;
 695
 696         /* str argument is a comma-separated list of functions */
 697         do {
 698                 str_entry = strsep(&str, ",");
 699                 if (str_entry) {
 700                         pr_debug("blacklisting initcall %s\n", str_entry);
 701                         entry = alloc_bootmem(sizeof(*entry));
 702                         entry->buf = alloc_bootmem(strlen(str_entry) + 1);
 703                         strcpy(entry->buf, str_entry);
 704                         list_add(&entry->next, &blacklisted_initcalls);
 705                 }
 706         } while (str_entry);
 707
 708         return 0;
 709 }
 710
 711 static bool __init_or_module initcall_blacklisted(initcall_t fn)
 712 {
 713         struct blacklist_entry *entry;
 714         char fn_name[KSYM_SYMBOL_LEN];
 715         unsigned long addr;
 716
 717         if (list_empty(&blacklisted_initcalls))
 718                 return false;
 719
 720         addr = (unsigned long) dereference_function_descriptor(fn);
 721         sprint_symbol_no_offset(fn_name, addr);
 722
 723         /*
 724          * fn will be "function_name [module_name]" where [module_name] is not
 725          * displayed for built-in init functions.  Strip off the [module_name].
 726          */
 727         strreplace(fn_name, ' ', '\0');
 728
 729         list_for_each_entry(entry, &blacklisted_initcalls, next) {
 730                 if (!strcmp(fn_name, entry->buf)) {
 731                         pr_debug("initcall %s blacklisted\n", fn_name);
 732                         return true;
 733                 }
 734         }
 735
 736         return false;
 737 }
 738 #else
 739 static int __init initcall_blacklist(char *str)
 740 {
 741         pr_warn("initcall_blacklist requires CONFIG_KALLSYMS\n");
 742         return 0;
 743 }
 744
 745 static bool __init_or_module initcall_blacklisted(initcall_t fn)
 746 {
 747         return false;
 748 }
 749 #endif
 750 __setup("initcall_blacklist=", initcall_blacklist);
 751
 752 static int __init_or_module do_one_initcall_debug(initcall_t fn)
 753 {
 754         ktime_t calltime, delta, rettime;
 755         unsigned long long duration;
 756         int ret;
 757
 758         printk(KERN_DEBUG "calling  %pF @ %i\n", fn, task_pid_nr(current));
 759         calltime = ktime_get();
 760         ret = fn();
 761         rettime = ktime_get();
 762         delta = ktime_sub(rettime, calltime);
 763         duration = (unsigned long long) ktime_to_ns(delta) >> 10;
 764         printk(KERN_DEBUG "initcall %pF returned %d after %lld usecs\n",
 765                  fn, ret, duration);
 766
 767         return ret;
 768 }
 769
 770 int __init_or_module do_one_initcall(initcall_t fn)
 771 {
 772         int count = preempt_count();
 773         int ret;
 774         char msgbuf[64];
 775
 776         if (initcall_blacklisted(fn))
 777                 return -EPERM;
 778
 779         if (initcall_debug)
 780                 ret = do_one_initcall_debug(fn);
 781         else
 782                 ret = fn();
 783
 784         msgbuf[0] = 0;
 785
 786         if (preempt_count() != count) {
 787                 sprintf(msgbuf, "preemption imbalance ");
 788                 preempt_count_set(count);
 789         }
 790         if (irqs_disabled()) {
 791                 strlcat(msgbuf, "disabled interrupts ", sizeof(msgbuf));
 792                 local_irq_enable();
 793         }
 794         WARN(msgbuf[0], "initcall %pF returned with %s\n", fn, msgbuf);
 795
 796         add_latent_entropy();
 797         return ret;
 798 }
 799
 800
 801 extern initcall_t __initcall_start[];
 802 extern initcall_t __initcall0_start[];
 803 extern initcall_t __initcall1_start[];
 804 extern initcall_t __initcall2_start[];
 805 extern initcall_t __initcall3_start[];
 806 extern initcall_t __initcall4_start[];
 807 extern initcall_t __initcall5_start[];
 808 extern initcall_t __initcall6_start[];
 809 extern initcall_t __initcall7_start[];
 810 extern initcall_t __initcall_end[];
 811
 812 static initcall_t *initcall_levels[] __initdata = {
 813         __initcall0_start,
 814         __initcall1_start,
 815         __initcall2_start,
 816         __initcall3_start,
 817         __initcall4_start,
 818         __initcall5_start,
 819         __initcall6_start,
 820         __initcall7_start,
 821         __initcall_end,
 822 };
 823
 824 /* Keep these in sync with initcalls in include/linux/init.h */
 825 static char *initcall_level_names[] __initdata = {
 826         "early",
 827         "core",
 828         "postcore",
 829         "arch",
 830         "subsys",
 831         "fs",
 832         "device",
 833         "late",
 834 };
 835
 836 static void __init do_initcall_level(int level)
 837 {
 838         initcall_t *fn;
 839
 840         strcpy(initcall_command_line, saved_command_line);
 841         parse_args(initcall_level_names[level],
 842                    initcall_command_line, __start___param,
 843                    __stop___param - __start___param,
 844                    level, level,
 845                    NULL, &repair_env_string);
 846
 847         for (fn = initcall_levels[level]; fn < initcall_levels[level+1]; fn++)
 848                 do_one_initcall(*fn);
 849 }
 850
 851 static void __init do_initcalls(void)
 852 {
 853         int level;
 854
 855         for (level = 0; level < ARRAY_SIZE(initcall_levels) - 1; level++)
 856                 do_initcall_level(level);
 857 }
 858
 859 /*
 860  * Ok, the machine is now initialized. None of the devices
 861  * have been touched yet, but the CPU subsystem is up and
 862  * running, and memory and process management works.
 863  *
 864  * Now we can finally start doing some real work..
 865  */
 866 static void __init do_basic_setup(void)
 867 {
 868         cpuset_init_smp();
 869         shmem_init();
 870         driver_init();
 871         init_irq_proc();
 872         do_ctors();
 873         usermodehelper_enable();
 874         do_initcalls();
 875         random_int_secret_init();
 876 }
 877
 878 static void __init do_pre_smp_initcalls(void)
 879 {
 880         initcall_t *fn;
 881
 882         for (fn = __initcall_start; fn < __initcall0_start; fn++)
 883                 do_one_initcall(*fn);
 884 }
 885
 886 /*
 887  * This function requests modules which should be loaded by default and is
 888  * called twice right after initrd is mounted and right before init is
 889  * exec'd.  If such modules are on either initrd or rootfs, they will be
 890  * loaded before control is passed to userland.
 891  */
 892 void __init load_default_modules(void)
 893 {
 894         load_default_elevator_module();
 895 }
 896
 897 static int run_init_process(const char *init_filename)
 898 {
 899         argv_init[0] = init_filename;
 900         return do_execve(getname_kernel(init_filename),
 901                 (const char __user *const __user *)argv_init,
 902                 (const char __user *const __user *)envp_init);
 903 }
 904
 905 static int try_to_run_init_process(const char *init_filename)
 906 {
 907         int ret;
 908
 909         ret = run_init_process(init_filename);
 910
 911         if (ret && ret != -ENOENT) {
 912                 pr_err("Starting init: %s exists but couldn't execute it (error %d)\n",
 913                        init_filename, ret);
 914         }
 915
 916         return ret;
 917 }
 918
 919 static noinline void __init kernel_init_freeable(void);
 920
 921 #ifdef CONFIG_DEBUG_RODATA
 922 static bool rodata_enabled = true;
 923 static int __init set_debug_rodata(char *str)
 924 {
 925         return strtobool(str, &rodata_enabled);
 926 }
 927 __setup("rodata=", set_debug_rodata);
 928
 929 static void mark_readonly(void)
 930 {
 931         if (rodata_enabled)
 932                 mark_rodata_ro();
 933         else
 934                 pr_info("Kernel memory protection disabled.\n");
 935 }
 936 #else
 937 static inline void mark_readonly(void)
 938 {
 939         pr_warn("This architecture does not have kernel memory protection.\n");
 940 }
 941 #endif
 942
 943 static int __ref kernel_init(void *unused)
 944 {
 945         int ret;
 946
 947         kernel_init_freeable();
 948         /* need to finish all async __init code before freeing the memory */
 949         async_synchronize_full();
 950         free_initmem();
 951         mark_readonly();
 952         system_state = SYSTEM_RUNNING;
 953         numa_default_policy();
 954
 955         flush_delayed_fput();
 956
 957         rcu_end_inkernel_boot();
 958
 959         if (ramdisk_execute_command) {
 960                 ret = run_init_process(ramdisk_execute_command);
 961                 if (!ret)
 962                         return 0;
 963                 pr_err("Failed to execute %s (error %d)\n",
 964                        ramdisk_execute_command, ret);
 965         }
 966
 967         /*
 968          * We try each of these until one succeeds.
 969          *
 970          * The Bourne shell can be used instead of init if we are
 971          * trying to recover a really broken machine.
 972          */
 973         if (execute_command) {
 974                 ret = run_init_process(execute_command);
 975                 if (!ret)
 976                         return 0;
 977                 panic("Requested init %s failed (error %d).",
 978                       execute_command, ret);
 979         }
 980         if (!try_to_run_init_process("/sbin/init") ||
 981             !try_to_run_init_process("/etc/init") ||
 982             !try_to_run_init_process("/bin/init") ||
 983             !try_to_run_init_process("/bin/sh"))
 984                 return 0;
 985
 986         panic("No working init found.  Try passing init= option to kernel. "
 987               "See Linux Documentation/init.txt for guidance.");
 988 }
 989
 990 static noinline void __init kernel_init_freeable(void)
 991 {
 992         /*
 993          * Wait until kthreadd is all set-up.
 994          */
 995         wait_for_completion(&kthreadd_done);
 996
 997         /* Now the scheduler is fully set up and can do blocking allocations */
 998         gfp_allowed_mask = __GFP_BITS_MASK;
 999
1000         /*
1001          * init can allocate pages on any node
1002          */
1003         set_mems_allowed(node_states[N_MEMORY]);
1004         /*
1005          * init can run on any cpu.
1006          */
1007         set_cpus_allowed_ptr(current, cpu_all_mask);
1008
1009         cad_pid = task_pid(current);
1010
1011         smp_prepare_cpus(setup_max_cpus);
1012
1013         do_pre_smp_initcalls();
1014         lockup_detector_init();
1015
1016         smp_init();
1017         sched_init_smp();
1018
1019         page_alloc_init_late();
1020
1021         do_basic_setup();
1022
1023         /* Open the /dev/console on the rootfs, this should never fail */
1024         if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0)
1025                 pr_err("Warning: unable to open an initial console.\n");
1026
1027         (void) sys_dup(0);
1028         (void) sys_dup(0);
1029         /*
1030          * check if there is an early userspace init.  If yes, let it do all
1031          * the work
1032          */
1033
1034         if (!ramdisk_execute_command)
1035                 ramdisk_execute_command = "/init";
1036
1037         if (sys_access((const char __user *) ramdisk_execute_command, 0) != 0) {
1038                 ramdisk_execute_command = NULL;
1039                 prepare_namespace();
1040         }
1041
1042         /*
1043          * Ok, we have completed the initial bootup, and
1044          * we're essentially up and running. Get rid of the
1045          * initmem segments and start the user-mode stuff..
1046          *
1047          * rootfs is available now, try loading the public keys
1048          * and default modules
1049          */
1050
1051         integrity_load_keys();
1052         load_default_modules();
1053 }