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/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
  82 #include <asm/io.h>
  83 #include <asm/bugs.h>
  84 #include <asm/setup.h>
  85 #include <asm/sections.h>
  86 #include <asm/cacheflush.h>
  87
  88 #ifdef CONFIG_X86_LOCAL_APIC
  89 #include <asm/smp.h>
  90 #endif
  91
  92 static int kernel_init(void *);
  93
  94 extern void init_IRQ(void);
  95 extern void fork_init(unsigned long);
  96 extern void radix_tree_init(void);
  97 #ifndef CONFIG_DEBUG_RODATA
  98 static inline void mark_rodata_ro(void) { }
  99 #endif
 100
 101 /*
 102  * Debug helper: via this flag we know that we are in 'early bootup code'
 103  * where only the boot processor is running with IRQ disabled.  This means
 104  * two things - IRQ must not be enabled before the flag is cleared and some
 105  * operations which are not allowed with IRQ disabled are allowed while the
 106  * flag is set.
 107  */
 108 bool early_boot_irqs_disabled __read_mostly;
 109
 110 enum system_states system_state __read_mostly;
 111 EXPORT_SYMBOL(system_state);
 112
 113 /*
 114  * Boot command-line arguments
 115  */
 116 #define MAX_INIT_ARGS CONFIG_INIT_ENV_ARG_LIMIT
 117 #define MAX_INIT_ENVS CONFIG_INIT_ENV_ARG_LIMIT
 118
 119 extern void time_init(void);
 120 /* Default late time init is NULL. archs can override this later. */
 121 void (*__initdata late_time_init)(void);
 122
 123 /* Untouched command line saved by arch-specific code. */
 124 char __initdata boot_command_line[COMMAND_LINE_SIZE];
 125 /* Untouched saved command line (eg. for /proc) */
 126 char *saved_command_line;
 127 /* Command line for parameter parsing */
 128 static char *static_command_line;
 129 /* Command line for per-initcall parameter parsing */
 130 static char *initcall_command_line;
 131
 132 static char *execute_command;
 133 static char *ramdisk_execute_command;
 134
 135 /*
 136  * Used to generate warnings if static_key manipulation functions are used
 137  * before jump_label_init is called.
 138  */
 139 bool static_key_initialized __read_mostly;
 140 EXPORT_SYMBOL_GPL(static_key_initialized);
 141
 142 /*
 143  * If set, this is an indication to the drivers that reset the underlying
 144  * device before going ahead with the initialization otherwise driver might
 145  * rely on the BIOS and skip the reset operation.
 146  *
 147  * This is useful if kernel is booting in an unreliable environment.
 148  * For ex. kdump situaiton where previous kernel has crashed, BIOS has been
 149  * skipped and devices will be in unknown state.
 150  */
 151 unsigned int reset_devices;
 152 EXPORT_SYMBOL(reset_devices);
 153
 154 static int __init set_reset_devices(char *str)
 155 {
 156         reset_devices = 1;
 157         return 1;
 158 }
 159
 160 __setup("reset_devices", set_reset_devices);
 161
 162 static const char *argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
 163 const char *envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, };
 164 static const char *panic_later, *panic_param;
 165
 166 extern const struct obs_kernel_param __setup_start[], __setup_end[];
 167
 168 static int __init obsolete_checksetup(char *line)
 169 {
 170         const struct obs_kernel_param *p;
 171         int had_early_param = 0;
 172
 173         p = __setup_start;
 174         do {
 175                 int n = strlen(p->str);
 176                 if (parameqn(line, p->str, n)) {
 177                         if (p->early) {
 178                                 /* Already done in parse_early_param?
 179                                  * (Needs exact match on param part).
 180                                  * Keep iterating, as we can have early
 181                                  * params and __setups of same names 8( */
 182                                 if (line[n] == '\0' || line[n] == '=')
 183                                         had_early_param = 1;
 184                         } else if (!p->setup_func) {
 185                                 pr_warn("Parameter %s is obsolete, ignored\n",
 186                                         p->str);
 187                                 return 1;
 188                         } else if (p->setup_func(line + n))
 189                                 return 1;
 190                 }
 191                 p++;
 192         } while (p < __setup_end);
 193
 194         return had_early_param;
 195 }
 196
 197 /*
 198  * This should be approx 2 Bo*oMips to start (note initial shift), and will
 199  * still work even if initially too large, it will just take slightly longer
 200  */
 201 unsigned long loops_per_jiffy = (1<<12);
 202 EXPORT_SYMBOL(loops_per_jiffy);
 203
 204 static int __init debug_kernel(char *str)
 205 {
 206         console_loglevel = CONSOLE_LOGLEVEL_DEBUG;
 207         return 0;
 208 }
 209
 210 static int __init quiet_kernel(char *str)
 211 {
 212         console_loglevel = CONSOLE_LOGLEVEL_QUIET;
 213         return 0;
 214 }
 215
 216 early_param("debug", debug_kernel);
 217 early_param("quiet", quiet_kernel);
 218
 219 static int __init loglevel(char *str)
 220 {
 221         int newlevel;
 222
 223         /*
 224          * Only update loglevel value when a correct setting was passed,
 225          * to prevent blind crashes (when loglevel being set to 0) that
 226          * are quite hard to debug
 227          */
 228         if (get_option(&str, &newlevel)) {
 229                 console_loglevel = newlevel;
 230                 return 0;
 231         }
 232
 233         return -EINVAL;
 234 }
 235
 236 early_param("loglevel", loglevel);
 237
 238 /* Change NUL term back to "=", to make "param" the whole string. */
 239 static int __init repair_env_string(char *param, char *val, const char *unused)
 240 {
 241         if (val) {
 242                 /* param=val or param="val"? */
 243                 if (val == param+strlen(param)+1)
 244                         val[-1] = '=';
 245                 else if (val == param+strlen(param)+2) {
 246                         val[-2] = '=';
 247                         memmove(val-1, val, strlen(val)+1);
 248                         val--;
 249                 } else
 250                         BUG();
 251         }
 252         return 0;
 253 }
 254
 255 /* Anything after -- gets handed straight to init. */
 256 static int __init set_init_arg(char *param, char *val, const char *unused)
 257 {
 258         unsigned int i;
 259
 260         if (panic_later)
 261                 return 0;
 262
 263         repair_env_string(param, val, unused);
 264
 265         for (i = 0; argv_init[i]; i++) {
 266                 if (i == MAX_INIT_ARGS) {
 267                         panic_later = "init";
 268                         panic_param = param;
 269                         return 0;
 270                 }
 271         }
 272         argv_init[i] = param;
 273         return 0;
 274 }
 275
 276 /*
 277  * Unknown boot options get handed to init, unless they look like
 278  * unused parameters (modprobe will find them in /proc/cmdline).
 279  */
 280 static int __init unknown_bootoption(char *param, char *val, const char *unused)
 281 {
 282         repair_env_string(param, val, unused);
 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 #ifdef CONFIG_X86_LOCAL_APIC
 353 static void __init smp_init(void)
 354 {
 355         APIC_init_uniprocessor();
 356 }
 357 #else
 358 #define smp_init()      do { } while (0)
 359 #endif
 360
 361 static inline void setup_nr_cpu_ids(void) { }
 362 static inline void smp_prepare_cpus(unsigned int maxcpus) { }
 363 #endif
 364
 365 /*
 366  * We need to store the untouched command line for future reference.
 367  * We also need to store the touched command line since the parameter
 368  * parsing is performed in place, and we should allow a component to
 369  * store reference of name/value for future reference.
 370  */
 371 static void __init setup_command_line(char *command_line)
 372 {
 373         saved_command_line =
 374                 memblock_virt_alloc(strlen(boot_command_line) + 1, 0);
 375         initcall_command_line =
 376                 memblock_virt_alloc(strlen(boot_command_line) + 1, 0);
 377         static_command_line = memblock_virt_alloc(strlen(command_line) + 1, 0);
 378         strcpy(saved_command_line, boot_command_line);
 379         strcpy(static_command_line, command_line);
 380 }
 381
 382 /*
 383  * We need to finalize in a non-__init function or else race conditions
 384  * between the root thread and the init thread may cause start_kernel to
 385  * be reaped by free_initmem before the root thread has proceeded to
 386  * cpu_idle.
 387  *
 388  * gcc-3.4 accidentally inlines this function, so use noinline.
 389  */
 390
 391 static __initdata DECLARE_COMPLETION(kthreadd_done);
 392
 393 static noinline void __init_refok rest_init(void)
 394 {
 395         int pid;
 396
 397         rcu_scheduler_starting();
 398         /*
 399          * We need to spawn init first so that it obtains pid 1, however
 400          * the init task will end up wanting to create kthreads, which, if
 401          * we schedule it before we create kthreadd, will OOPS.
 402          */
 403         kernel_thread(kernel_init, NULL, CLONE_FS);
 404         numa_default_policy();
 405         pid = kernel_thread(kthreadd, NULL, CLONE_FS | CLONE_FILES);
 406         rcu_read_lock();
 407         kthreadd_task = find_task_by_pid_ns(pid, &init_pid_ns);
 408         rcu_read_unlock();
 409         complete(&kthreadd_done);
 410
 411         /*
 412          * The boot idle thread must execute schedule()
 413          * at least once to get things moving:
 414          */
 415         init_idle_bootup_task(current);
 416         schedule_preempt_disabled();
 417         /* Call into cpu_idle with preempt disabled */
 418         cpu_startup_entry(CPUHP_ONLINE);
 419 }
 420
 421 /* Check for early params. */
 422 static int __init do_early_param(char *param, char *val, const char *unused)
 423 {
 424         const struct obs_kernel_param *p;
 425
 426         for (p = __setup_start; p < __setup_end; p++) {
 427                 if ((p->early && parameq(param, p->str)) ||
 428                     (strcmp(param, "console") == 0 &&
 429                      strcmp(p->str, "earlycon") == 0)
 430                 ) {
 431                         if (p->setup_func(val) != 0)
 432                                 pr_warn("Malformed early option '%s'\n", param);
 433                 }
 434         }
 435         /* We accept everything at this stage. */
 436         return 0;
 437 }
 438
 439 void __init parse_early_options(char *cmdline)
 440 {
 441         parse_args("early options", cmdline, NULL, 0, 0, 0, do_early_param);
 442 }
 443
 444 /* Arch code calls this early on, or if not, just before other parsing. */
 445 void __init parse_early_param(void)
 446 {
 447         static int done __initdata;
 448         static char tmp_cmdline[COMMAND_LINE_SIZE] __initdata;
 449
 450         if (done)
 451                 return;
 452
 453         /* All fall through to do_early_param. */
 454         strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);
 455         parse_early_options(tmp_cmdline);
 456         done = 1;
 457 }
 458
 459 /*
 460  *      Activate the first processor.
 461  */
 462
 463 static void __init boot_cpu_init(void)
 464 {
 465         int cpu = smp_processor_id();
 466         /* Mark the boot cpu "present", "online" etc for SMP and UP case */
 467         set_cpu_online(cpu, true);
 468         set_cpu_active(cpu, true);
 469         set_cpu_present(cpu, true);
 470         set_cpu_possible(cpu, true);
 471 }
 472
 473 void __init __weak smp_setup_processor_id(void)
 474 {
 475 }
 476
 477 # if THREAD_SIZE >= PAGE_SIZE
 478 void __init __weak thread_info_cache_init(void)
 479 {
 480 }
 481 #endif
 482
 483 /*
 484  * Set up kernel memory allocators
 485  */
 486 static void __init mm_init(void)
 487 {
 488         /*
 489          * page_ext requires contiguous pages,
 490          * bigger than MAX_ORDER unless SPARSEMEM.
 491          */
 492         page_ext_init_flatmem();
 493         mem_init();
 494         kmem_cache_init();
 495         percpu_init_late();
 496         pgtable_init();
 497         vmalloc_init();
 498 }
 499
 500 asmlinkage __visible void __init start_kernel(void)
 501 {
 502         char *command_line;
 503         char *after_dashes;
 504
 505         /*
 506          * Need to run as early as possible, to initialize the
 507          * lockdep hash:
 508          */
 509         lockdep_init();
 510         set_task_stack_end_magic(&init_task);
 511         smp_setup_processor_id();
 512         debug_objects_early_init();
 513
 514         /*
 515          * Set up the the initial canary ASAP:
 516          */
 517         boot_init_stack_canary();
 518
 519         cgroup_init_early();
 520
 521         local_irq_disable();
 522         early_boot_irqs_disabled = true;
 523
 524 /*
 525  * Interrupts are still disabled. Do necessary setups, then
 526  * enable them
 527  */
 528         boot_cpu_init();
 529         page_address_init();
 530         pr_notice("%s", linux_banner);
 531         setup_arch(&command_line);
 532         mm_init_cpumask(&init_mm);
 533         setup_command_line(command_line);
 534         setup_nr_cpu_ids();
 535         setup_per_cpu_areas();
 536         smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */
 537
 538         build_all_zonelists(NULL, NULL);
 539         page_alloc_init();
 540
 541         pr_notice("Kernel command line: %s\n", boot_command_line);
 542         parse_early_param();
 543         after_dashes = parse_args("Booting kernel",
 544                                   static_command_line, __start___param,
 545                                   __stop___param - __start___param,
 546                                   -1, -1, &unknown_bootoption);
 547         if (!IS_ERR_OR_NULL(after_dashes))
 548                 parse_args("Setting init args", after_dashes, NULL, 0, -1, -1,
 549                            set_init_arg);
 550
 551         jump_label_init();
 552
 553         /*
 554          * These use large bootmem allocations and must precede
 555          * kmem_cache_init()
 556          */
 557         setup_log_buf(0);
 558         pidhash_init();
 559         vfs_caches_init_early();
 560         sort_main_extable();
 561         trap_init();
 562         mm_init();
 563
 564         /*
 565          * Set up the scheduler prior starting any interrupts (such as the
 566          * timer interrupt). Full topology setup happens at smp_init()
 567          * time - but meanwhile we still have a functioning scheduler.
 568          */
 569         sched_init();
 570         /*
 571          * Disable preemption - early bootup scheduling is extremely
 572          * fragile until we cpu_idle() for the first time.
 573          */
 574         preempt_disable();
 575         if (WARN(!irqs_disabled(),
 576                  "Interrupts were enabled *very* early, fixing it\n"))
 577                 local_irq_disable();
 578         idr_init_cache();
 579         rcu_init();
 580         context_tracking_init();
 581         radix_tree_init();
 582         /* init some links before init_ISA_irqs() */
 583         early_irq_init();
 584         init_IRQ();
 585         tick_init();
 586         rcu_init_nohz();
 587         init_timers();
 588         hrtimers_init();
 589         softirq_init();
 590         timekeeping_init();
 591         time_init();
 592         sched_clock_postinit();
 593         perf_event_init();
 594         profile_init();
 595         call_function_init();
 596         WARN(!irqs_disabled(), "Interrupts were enabled early\n");
 597         early_boot_irqs_disabled = false;
 598         local_irq_enable();
 599
 600         kmem_cache_init_late();
 601
 602         /*
 603          * HACK ALERT! This is early. We're enabling the console before
 604          * we've done PCI setups etc, and console_init() must be aware of
 605          * this. But we do want output early, in case something goes wrong.
 606          */
 607         console_init();
 608         if (panic_later)
 609                 panic("Too many boot %s vars at `%s'", panic_later,
 610                       panic_param);
 611
 612         lockdep_info();
 613
 614         /*
 615          * Need to run this when irqs are enabled, because it wants
 616          * to self-test [hard/soft]-irqs on/off lock inversion bugs
 617          * too:
 618          */
 619         locking_selftest();
 620
 621 #ifdef CONFIG_BLK_DEV_INITRD
 622         if (initrd_start && !initrd_below_start_ok &&
 623             page_to_pfn(virt_to_page((void *)initrd_start)) < min_low_pfn) {
 624                 pr_crit("initrd overwritten (0x%08lx < 0x%08lx) - disabling it.\n",
 625                     page_to_pfn(virt_to_page((void *)initrd_start)),
 626                     min_low_pfn);
 627                 initrd_start = 0;
 628         }
 629 #endif
 630         page_ext_init();
 631         debug_objects_mem_init();
 632         kmemleak_init();
 633         setup_per_cpu_pageset();
 634         numa_policy_init();
 635         if (late_time_init)
 636                 late_time_init();
 637         sched_clock_init();
 638         calibrate_delay();
 639         pidmap_init();
 640         anon_vma_init();
 641         acpi_early_init();
 642 #ifdef CONFIG_X86
 643         if (efi_enabled(EFI_RUNTIME_SERVICES))
 644                 efi_enter_virtual_mode();
 645 #endif
 646 #ifdef CONFIG_X86_ESPFIX64
 647         /* Should be run before the first non-init thread is created */
 648         init_espfix_bsp();
 649 #endif
 650         thread_info_cache_init();
 651         cred_init();
 652         fork_init(totalram_pages);
 653         proc_caches_init();
 654         buffer_init();
 655         key_init();
 656         security_init();
 657         dbg_late_init();
 658         vfs_caches_init(totalram_pages);
 659         signals_init();
 660         /* rootfs populating might need page-writeback */
 661         page_writeback_init();
 662         proc_root_init();
 663         cgroup_init();
 664         cpuset_init();
 665         taskstats_init_early();
 666         delayacct_init();
 667
 668         check_bugs();
 669
 670         sfi_init_late();
 671
 672         if (efi_enabled(EFI_RUNTIME_SERVICES)) {
 673                 efi_late_init();
 674                 efi_free_boot_services();
 675         }
 676
 677         ftrace_init();
 678
 679         /* Do the rest non-__init'ed, we're now alive */
 680         rest_init();
 681 }
 682
 683 /* Call all constructor functions linked into the kernel. */
 684 static void __init do_ctors(void)
 685 {
 686 #ifdef CONFIG_CONSTRUCTORS
 687         ctor_fn_t *fn = (ctor_fn_t *) __ctors_start;
 688
 689         for (; fn < (ctor_fn_t *) __ctors_end; fn++)
 690                 (*fn)();
 691 #endif
 692 }
 693
 694 bool initcall_debug;
 695 core_param(initcall_debug, initcall_debug, bool, 0644);
 696
 697 #ifdef CONFIG_KALLSYMS
 698 struct blacklist_entry {
 699         struct list_head next;
 700         char *buf;
 701 };
 702
 703 static __initdata_or_module LIST_HEAD(blacklisted_initcalls);
 704
 705 static int __init initcall_blacklist(char *str)
 706 {
 707         char *str_entry;
 708         struct blacklist_entry *entry;
 709
 710         /* str argument is a comma-separated list of functions */
 711         do {
 712                 str_entry = strsep(&str, ",");
 713                 if (str_entry) {
 714                         pr_debug("blacklisting initcall %s\n", str_entry);
 715                         entry = alloc_bootmem(sizeof(*entry));
 716                         entry->buf = alloc_bootmem(strlen(str_entry) + 1);
 717                         strcpy(entry->buf, str_entry);
 718                         list_add(&entry->next, &blacklisted_initcalls);
 719                 }
 720         } while (str_entry);
 721
 722         return 0;
 723 }
 724
 725 static bool __init_or_module initcall_blacklisted(initcall_t fn)
 726 {
 727         struct list_head *tmp;
 728         struct blacklist_entry *entry;
 729         char *fn_name;
 730
 731         fn_name = kasprintf(GFP_KERNEL, "%pf", fn);
 732         if (!fn_name)
 733                 return false;
 734
 735         list_for_each(tmp, &blacklisted_initcalls) {
 736                 entry = list_entry(tmp, struct blacklist_entry, next);
 737                 if (!strcmp(fn_name, entry->buf)) {
 738                         pr_debug("initcall %s blacklisted\n", fn_name);
 739                         kfree(fn_name);
 740                         return true;
 741                 }
 742         }
 743
 744         kfree(fn_name);
 745         return false;
 746 }
 747 #else
 748 static int __init initcall_blacklist(char *str)
 749 {
 750         pr_warn("initcall_blacklist requires CONFIG_KALLSYMS\n");
 751         return 0;
 752 }
 753
 754 static bool __init_or_module initcall_blacklisted(initcall_t fn)
 755 {
 756         return false;
 757 }
 758 #endif
 759 __setup("initcall_blacklist=", initcall_blacklist);
 760
 761 static int __init_or_module do_one_initcall_debug(initcall_t fn)
 762 {
 763         ktime_t calltime, delta, rettime;
 764         unsigned long long duration;
 765         int ret;
 766
 767         printk(KERN_DEBUG "calling  %pF @ %i\n", fn, task_pid_nr(current));
 768         calltime = ktime_get();
 769         ret = fn();
 770         rettime = ktime_get();
 771         delta = ktime_sub(rettime, calltime);
 772         duration = (unsigned long long) ktime_to_ns(delta) >> 10;
 773         printk(KERN_DEBUG "initcall %pF returned %d after %lld usecs\n",
 774                  fn, ret, duration);
 775
 776         return ret;
 777 }
 778
 779 int __init_or_module do_one_initcall(initcall_t fn)
 780 {
 781         int count = preempt_count();
 782         int ret;
 783         char msgbuf[64];
 784
 785         if (initcall_blacklisted(fn))
 786                 return -EPERM;
 787
 788         if (initcall_debug)
 789                 ret = do_one_initcall_debug(fn);
 790         else
 791                 ret = fn();
 792
 793         msgbuf[0] = 0;
 794
 795         if (preempt_count() != count) {
 796                 sprintf(msgbuf, "preemption imbalance ");
 797                 preempt_count_set(count);
 798         }
 799         if (irqs_disabled()) {
 800                 strlcat(msgbuf, "disabled interrupts ", sizeof(msgbuf));
 801                 local_irq_enable();
 802         }
 803         WARN(msgbuf[0], "initcall %pF returned with %s\n", fn, msgbuf);
 804
 805         return ret;
 806 }
 807
 808
 809 extern initcall_t __initcall_start[];
 810 extern initcall_t __initcall0_start[];
 811 extern initcall_t __initcall1_start[];
 812 extern initcall_t __initcall2_start[];
 813 extern initcall_t __initcall3_start[];
 814 extern initcall_t __initcall4_start[];
 815 extern initcall_t __initcall5_start[];
 816 extern initcall_t __initcall6_start[];
 817 extern initcall_t __initcall7_start[];
 818 extern initcall_t __initcall_end[];
 819
 820 static initcall_t *initcall_levels[] __initdata = {
 821         __initcall0_start,
 822         __initcall1_start,
 823         __initcall2_start,
 824         __initcall3_start,
 825         __initcall4_start,
 826         __initcall5_start,
 827         __initcall6_start,
 828         __initcall7_start,
 829         __initcall_end,
 830 };
 831
 832 /* Keep these in sync with initcalls in include/linux/init.h */
 833 static char *initcall_level_names[] __initdata = {
 834         "early",
 835         "core",
 836         "postcore",
 837         "arch",
 838         "subsys",
 839         "fs",
 840         "device",
 841         "late",
 842 };
 843
 844 static void __init do_initcall_level(int level)
 845 {
 846         initcall_t *fn;
 847
 848         strcpy(initcall_command_line, saved_command_line);
 849         parse_args(initcall_level_names[level],
 850                    initcall_command_line, __start___param,
 851                    __stop___param - __start___param,
 852                    level, level,
 853                    &repair_env_string);
 854
 855         for (fn = initcall_levels[level]; fn < initcall_levels[level+1]; fn++)
 856                 do_one_initcall(*fn);
 857 }
 858
 859 static void __init do_initcalls(void)
 860 {
 861         int level;
 862
 863         for (level = 0; level < ARRAY_SIZE(initcall_levels) - 1; level++)
 864                 do_initcall_level(level);
 865 }
 866
 867 /*
 868  * Ok, the machine is now initialized. None of the devices
 869  * have been touched yet, but the CPU subsystem is up and
 870  * running, and memory and process management works.
 871  *
 872  * Now we can finally start doing some real work..
 873  */
 874 static void __init do_basic_setup(void)
 875 {
 876         cpuset_init_smp();
 877         usermodehelper_init();
 878         shmem_init();
 879         driver_init();
 880         init_irq_proc();
 881         do_ctors();
 882         usermodehelper_enable();
 883         do_initcalls();
 884         random_int_secret_init();
 885 }
 886
 887 static void __init do_pre_smp_initcalls(void)
 888 {
 889         initcall_t *fn;
 890
 891         for (fn = __initcall_start; fn < __initcall0_start; fn++)
 892                 do_one_initcall(*fn);
 893 }
 894
 895 /*
 896  * This function requests modules which should be loaded by default and is
 897  * called twice right after initrd is mounted and right before init is
 898  * exec'd.  If such modules are on either initrd or rootfs, they will be
 899  * loaded before control is passed to userland.
 900  */
 901 void __init load_default_modules(void)
 902 {
 903         load_default_elevator_module();
 904 }
 905
 906 static int run_init_process(const char *init_filename)
 907 {
 908         argv_init[0] = init_filename;
 909         return do_execve(getname_kernel(init_filename),
 910                 (const char __user *const __user *)argv_init,
 911                 (const char __user *const __user *)envp_init);
 912 }
 913
 914 static int try_to_run_init_process(const char *init_filename)
 915 {
 916         int ret;
 917
 918         ret = run_init_process(init_filename);
 919
 920         if (ret && ret != -ENOENT) {
 921                 pr_err("Starting init: %s exists but couldn't execute it (error %d)\n",
 922                        init_filename, ret);
 923         }
 924
 925         return ret;
 926 }
 927
 928 static noinline void __init kernel_init_freeable(void);
 929
 930 static int __ref kernel_init(void *unused)
 931 {
 932         int ret;
 933
 934         kernel_init_freeable();
 935         /* need to finish all async __init code before freeing the memory */
 936         async_synchronize_full();
 937         free_initmem();
 938         mark_rodata_ro();
 939         system_state = SYSTEM_RUNNING;
 940         numa_default_policy();
 941
 942         flush_delayed_fput();
 943
 944         if (ramdisk_execute_command) {
 945                 ret = run_init_process(ramdisk_execute_command);
 946                 if (!ret)
 947                         return 0;
 948                 pr_err("Failed to execute %s (error %d)\n",
 949                        ramdisk_execute_command, ret);
 950         }
 951
 952         /*
 953          * We try each of these until one succeeds.
 954          *
 955          * The Bourne shell can be used instead of init if we are
 956          * trying to recover a really broken machine.
 957          */
 958         if (execute_command) {
 959                 ret = run_init_process(execute_command);
 960                 if (!ret)
 961                         return 0;
 962 #ifndef CONFIG_INIT_FALLBACK
 963                 panic("Requested init %s failed (error %d).",
 964                       execute_command, ret);
 965 #else
 966                 pr_err("Failed to execute %s (error %d).  Attempting defaults...\n",
 967                        execute_command, ret);
 968 #endif
 969         }
 970         if (!try_to_run_init_process("/sbin/init") ||
 971             !try_to_run_init_process("/etc/init") ||
 972             !try_to_run_init_process("/bin/init") ||
 973             !try_to_run_init_process("/bin/sh"))
 974                 return 0;
 975
 976         panic("No working init found.  Try passing init= option to kernel. "
 977               "See Linux Documentation/init.txt for guidance.");
 978 }
 979
 980 static noinline void __init kernel_init_freeable(void)
 981 {
 982         /*
 983          * Wait until kthreadd is all set-up.
 984          */
 985         wait_for_completion(&kthreadd_done);
 986
 987         /* Now the scheduler is fully set up and can do blocking allocations */
 988         gfp_allowed_mask = __GFP_BITS_MASK;
 989
 990         /*
 991          * init can allocate pages on any node
 992          */
 993         set_mems_allowed(node_states[N_MEMORY]);
 994         /*
 995          * init can run on any cpu.
 996          */
 997         set_cpus_allowed_ptr(current, cpu_all_mask);
 998
 999         cad_pid = task_pid(current);
1000
1001         smp_prepare_cpus(setup_max_cpus);
1002
1003         do_pre_smp_initcalls();
1004         lockup_detector_init();
1005
1006         smp_init();
1007         sched_init_smp();
1008
1009         do_basic_setup();
1010
1011         /* Open the /dev/console on the rootfs, this should never fail */
1012         if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0)
1013                 pr_err("Warning: unable to open an initial console.\n");
1014
1015         (void) sys_dup(0);
1016         (void) sys_dup(0);
1017         /*
1018          * check if there is an early userspace init.  If yes, let it do all
1019          * the work
1020          */
1021
1022         if (!ramdisk_execute_command)
1023                 ramdisk_execute_command = "/init";
1024
1025         if (sys_access((const char __user *) ramdisk_execute_command, 0) != 0) {
1026                 ramdisk_execute_command = NULL;
1027                 prepare_namespace();
1028         }
1029
1030         /*
1031          * Ok, we have completed the initial bootup, and
1032          * we're essentially up and running. Get rid of the
1033          * initmem segments and start the user-mode stuff..
1034          */
1035
1036         /* rootfs is available now, try loading default modules */
1037         load_default_modules();
1038 }