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 #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
  97 /*
  98  * Debug helper: via this flag we know that we are in 'early bootup code'
  99  * where only the boot processor is running with IRQ disabled.  This means
 100  * two things - IRQ must not be enabled before the flag is cleared and some
 101  * operations which are not allowed with IRQ disabled are allowed while the
 102  * flag is set.
 103  */
 104 bool early_boot_irqs_disabled __read_mostly;
 105
 106 enum system_states system_state __read_mostly;
 107 EXPORT_SYMBOL(system_state);
 108
 109 /*
 110  * Boot command-line arguments
 111  */
 112 #define MAX_INIT_ARGS CONFIG_INIT_ENV_ARG_LIMIT
 113 #define MAX_INIT_ENVS CONFIG_INIT_ENV_ARG_LIMIT
 114
 115 extern void time_init(void);
 116 /* Default late time init is NULL. archs can override this later. */
 117 void (*__initdata late_time_init)(void);
 118
 119 /* Untouched command line saved by arch-specific code. */
 120 char __initdata boot_command_line[COMMAND_LINE_SIZE];
 121 /* Untouched saved command line (eg. for /proc) */
 122 char *saved_command_line;
 123 /* Command line for parameter parsing */
 124 static char *static_command_line;
 125 /* Command line for per-initcall parameter parsing */
 126 static char *initcall_command_line;
 127
 128 static char *execute_command;
 129 static char *ramdisk_execute_command;
 130
 131 /*
 132  * Used to generate warnings if static_key manipulation functions are used
 133  * before jump_label_init is called.
 134  */
 135 bool static_key_initialized __read_mostly;
 136 EXPORT_SYMBOL_GPL(static_key_initialized);
 137
 138 /*
 139  * If set, this is an indication to the drivers that reset the underlying
 140  * device before going ahead with the initialization otherwise driver might
 141  * rely on the BIOS and skip the reset operation.
 142  *
 143  * This is useful if kernel is booting in an unreliable environment.
 144  * For ex. kdump situation where previous kernel has crashed, BIOS has been
 145  * skipped and devices will be in unknown state.
 146  */
 147 unsigned int reset_devices;
 148 EXPORT_SYMBOL(reset_devices);
 149
 150 static int __init set_reset_devices(char *str)
 151 {
 152         reset_devices = 1;
 153         return 1;
 154 }
 155
 156 __setup("reset_devices", set_reset_devices);
 157
 158 static const char *argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
 159 const char *envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, };
 160 static const char *panic_later, *panic_param;
 161
 162 extern const struct obs_kernel_param __setup_start[], __setup_end[];
 163
 164 static bool __init obsolete_checksetup(char *line)
 165 {
 166         const struct obs_kernel_param *p;
 167         bool had_early_param = false;
 168
 169         p = __setup_start;
 170         do {
 171                 int n = strlen(p->str);
 172                 if (parameqn(line, p->str, n)) {
 173                         if (p->early) {
 174                                 /* Already done in parse_early_param?
 175                                  * (Needs exact match on param part).
 176                                  * Keep iterating, as we can have early
 177                                  * params and __setups of same names 8( */
 178                                 if (line[n] == '\0' || line[n] == '=')
 179                                         had_early_param = true;
 180                         } else if (!p->setup_func) {
 181                                 pr_warn("Parameter %s is obsolete, ignored\n",
 182                                         p->str);
 183                                 return true;
 184                         } else if (p->setup_func(line + n))
 185                                 return true;
 186                 }
 187                 p++;
 188         } while (p < __setup_end);
 189
 190         return had_early_param;
 191 }
 192
 193 /*
 194  * This should be approx 2 Bo*oMips to start (note initial shift), and will
 195  * still work even if initially too large, it will just take slightly longer
 196  */
 197 unsigned long loops_per_jiffy = (1<<12);
 198 EXPORT_SYMBOL(loops_per_jiffy);
 199
 200 static int __init debug_kernel(char *str)
 201 {
 202         console_loglevel = CONSOLE_LOGLEVEL_DEBUG;
 203         return 0;
 204 }
 205
 206 static int __init quiet_kernel(char *str)
 207 {
 208         console_loglevel = CONSOLE_LOGLEVEL_QUIET;
 209         return 0;
 210 }
 211
 212 early_param("debug", debug_kernel);
 213 early_param("quiet", quiet_kernel);
 214
 215 static int __init loglevel(char *str)
 216 {
 217         int newlevel;
 218
 219         /*
 220          * Only update loglevel value when a correct setting was passed,
 221          * to prevent blind crashes (when loglevel being set to 0) that
 222          * are quite hard to debug
 223          */
 224         if (get_option(&str, &newlevel)) {
 225                 console_loglevel = newlevel;
 226                 return 0;
 227         }
 228
 229         return -EINVAL;
 230 }
 231
 232 early_param("loglevel", loglevel);
 233
 234 /* Change NUL term back to "=", to make "param" the whole string. */
 235 static int __init repair_env_string(char *param, char *val,
 236                                     const char *unused, void *arg)
 237 {
 238         if (val) {
 239                 /* param=val or param="val"? */
 240                 if (val == param+strlen(param)+1)
 241                         val[-1] = '=';
 242                 else if (val == param+strlen(param)+2) {
 243                         val[-2] = '=';
 244                         memmove(val-1, val, strlen(val)+1);
 245                         val--;
 246                 } else
 247                         BUG();
 248         }
 249         return 0;
 250 }
 251
 252 /* Anything after -- gets handed straight to init. */
 253 static int __init set_init_arg(char *param, char *val,
 254                                const char *unused, void *arg)
 255 {
 256         unsigned int i;
 257
 258         if (panic_later)
 259                 return 0;
 260
 261         repair_env_string(param, val, unused, NULL);
 262
 263         for (i = 0; argv_init[i]; i++) {
 264                 if (i == MAX_INIT_ARGS) {
 265                         panic_later = "init";
 266                         panic_param = param;
 267                         return 0;
 268                 }
 269         }
 270         argv_init[i] = param;
 271         return 0;
 272 }
 273
 274 /*
 275  * Unknown boot options get handed to init, unless they look like
 276  * unused parameters (modprobe will find them in /proc/cmdline).
 277  */
 278 static int __init unknown_bootoption(char *param, char *val,
 279                                      const char *unused, void *arg)
 280 {
 281         repair_env_string(param, val, unused, NULL);
 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         /*
 389          * We need to spawn init first so that it obtains pid 1, however
 390          * the init task will end up wanting to create kthreads, which, if
 391          * we schedule it before we create kthreadd, will OOPS.
 392          */
 393         kernel_thread(kernel_init, NULL, CLONE_FS);
 394         numa_default_policy();
 395         pid = kernel_thread(kthreadd, NULL, CLONE_FS | CLONE_FILES);
 396         rcu_read_lock();
 397         kthreadd_task = find_task_by_pid_ns(pid, &init_pid_ns);
 398         rcu_read_unlock();
 399         complete(&kthreadd_done);
 400
 401         /*
 402          * The boot idle thread must execute schedule()
 403          * at least once to get things moving:
 404          */
 405         init_idle_bootup_task(current);
 406         schedule_preempt_disabled();
 407         /* Call into cpu_idle with preempt disabled */
 408         cpu_startup_entry(CPUHP_ONLINE);
 409 }
 410
 411 /* Check for early params. */
 412 static int __init do_early_param(char *param, char *val,
 413                                  const char *unused, void *arg)
 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, NULL,
 433                    do_early_param);
 434 }
 435
 436 /* Arch code calls this early on, or if not, just before other parsing. */
 437 void __init parse_early_param(void)
 438 {
 439         static int done __initdata;
 440         static char tmp_cmdline[COMMAND_LINE_SIZE] __initdata;
 441
 442         if (done)
 443                 return;
 444
 445         /* All fall through to do_early_param. */
 446         strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);
 447         parse_early_options(tmp_cmdline);
 448         done = 1;
 449 }
 450
 451 void __init __weak smp_setup_processor_id(void)
 452 {
 453 }
 454
 455 # if THREAD_SIZE >= PAGE_SIZE
 456 void __init __weak thread_info_cache_init(void)
 457 {
 458 }
 459 #endif
 460
 461 /*
 462  * Set up kernel memory allocators
 463  */
 464 static void __init mm_init(void)
 465 {
 466         /*
 467          * page_ext requires contiguous pages,
 468          * bigger than MAX_ORDER unless SPARSEMEM.
 469          */
 470         page_ext_init_flatmem();
 471         mem_init();
 472         kmem_cache_init();
 473         percpu_init_late();
 474         pgtable_init();
 475         vmalloc_init();
 476         ioremap_huge_init();
 477 }
 478
 479 asmlinkage __visible void __init start_kernel(void)
 480 {
 481         char *command_line;
 482         char *after_dashes;
 483
 484         set_task_stack_end_magic(&init_task);
 485         smp_setup_processor_id();
 486         debug_objects_early_init();
 487
 488         /*
 489          * Set up the the initial canary ASAP:
 490          */
 491         boot_init_stack_canary();
 492
 493         cgroup_init_early();
 494
 495         local_irq_disable();
 496         early_boot_irqs_disabled = true;
 497
 498 /*
 499  * Interrupts are still disabled. Do necessary setups, then
 500  * enable them
 501  */
 502         boot_cpu_init();
 503         page_address_init();
 504         pr_notice("%s", linux_banner);
 505         setup_arch(&command_line);
 506         mm_init_cpumask(&init_mm);
 507         setup_command_line(command_line);
 508         setup_nr_cpu_ids();
 509         setup_per_cpu_areas();
 510         boot_cpu_state_init();
 511         smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */
 512
 513         build_all_zonelists(NULL, NULL);
 514         page_alloc_init();
 515
 516         pr_notice("Kernel command line: %s\n", boot_command_line);
 517         parse_early_param();
 518         after_dashes = parse_args("Booting kernel",
 519                                   static_command_line, __start___param,
 520                                   __stop___param - __start___param,
 521                                   -1, -1, NULL, &unknown_bootoption);
 522         if (!IS_ERR_OR_NULL(after_dashes))
 523                 parse_args("Setting init args", after_dashes, NULL, 0, -1, -1,
 524                            NULL, set_init_arg);
 525
 526         jump_label_init();
 527
 528         /*
 529          * These use large bootmem allocations and must precede
 530          * kmem_cache_init()
 531          */
 532         setup_log_buf(0);
 533         pidhash_init();
 534         vfs_caches_init_early();
 535         sort_main_extable();
 536         trap_init();
 537         mm_init();
 538
 539         /*
 540          * Set up the scheduler prior starting any interrupts (such as the
 541          * timer interrupt). Full topology setup happens at smp_init()
 542          * time - but meanwhile we still have a functioning scheduler.
 543          */
 544         sched_init();
 545         /*
 546          * Disable preemption - early bootup scheduling is extremely
 547          * fragile until we cpu_idle() for the first time.
 548          */
 549         preempt_disable();
 550         if (WARN(!irqs_disabled(),
 551                  "Interrupts were enabled *very* early, fixing it\n"))
 552                 local_irq_disable();
 553         idr_init_cache();
 554         rcu_init();
 555
 556         /* trace_printk() and trace points may be used after this */
 557         trace_init();
 558
 559         context_tracking_init();
 560         radix_tree_init();
 561         /* init some links before init_ISA_irqs() */
 562         early_irq_init();
 563         init_IRQ();
 564         tick_init();
 565         rcu_init_nohz();
 566         init_timers();
 567         hrtimers_init();
 568         softirq_init();
 569         timekeeping_init();
 570         time_init();
 571         sched_clock_postinit();
 572         printk_nmi_init();
 573         perf_event_init();
 574         profile_init();
 575         call_function_init();
 576         WARN(!irqs_disabled(), "Interrupts were enabled early\n");
 577         early_boot_irqs_disabled = false;
 578         local_irq_enable();
 579
 580         kmem_cache_init_late();
 581
 582         /*
 583          * HACK ALERT! This is early. We're enabling the console before
 584          * we've done PCI setups etc, and console_init() must be aware of
 585          * this. But we do want output early, in case something goes wrong.
 586          */
 587         console_init();
 588         if (panic_later)
 589                 panic("Too many boot %s vars at `%s'", panic_later,
 590                       panic_param);
 591
 592         lockdep_info();
 593
 594         /*
 595          * Need to run this when irqs are enabled, because it wants
 596          * to self-test [hard/soft]-irqs on/off lock inversion bugs
 597          * too:
 598          */
 599         locking_selftest();
 600
 601 #ifdef CONFIG_BLK_DEV_INITRD
 602         if (initrd_start && !initrd_below_start_ok &&
 603             page_to_pfn(virt_to_page((void *)initrd_start)) < min_low_pfn) {
 604                 pr_crit("initrd overwritten (0x%08lx < 0x%08lx) - disabling it.\n",
 605                     page_to_pfn(virt_to_page((void *)initrd_start)),
 606                     min_low_pfn);
 607                 initrd_start = 0;
 608         }
 609 #endif
 610         page_ext_init();
 611         debug_objects_mem_init();
 612         kmemleak_init();
 613         setup_per_cpu_pageset();
 614         numa_policy_init();
 615         if (late_time_init)
 616                 late_time_init();
 617         sched_clock_init();
 618         calibrate_delay();
 619         pidmap_init();
 620         anon_vma_init();
 621         acpi_early_init();
 622 #ifdef CONFIG_X86
 623         if (efi_enabled(EFI_RUNTIME_SERVICES))
 624                 efi_enter_virtual_mode();
 625 #endif
 626 #ifdef CONFIG_X86_ESPFIX64
 627         /* Should be run before the first non-init thread is created */
 628         init_espfix_bsp();
 629 #endif
 630         thread_info_cache_init();
 631         cred_init();
 632         fork_init();
 633         proc_caches_init();
 634         buffer_init();
 635         key_init();
 636         security_init();
 637         dbg_late_init();
 638         vfs_caches_init();
 639         signals_init();
 640         /* rootfs populating might need page-writeback */
 641         page_writeback_init();
 642         proc_root_init();
 643         nsfs_init();
 644         cpuset_init();
 645         cgroup_init();
 646         taskstats_init_early();
 647         delayacct_init();
 648
 649         check_bugs();
 650
 651         acpi_subsystem_init();
 652         sfi_init_late();
 653
 654         if (efi_enabled(EFI_RUNTIME_SERVICES)) {
 655                 efi_late_init();
 656                 efi_free_boot_services();
 657         }
 658
 659         ftrace_init();
 660
 661         /* Do the rest non-__init'ed, we're now alive */
 662         rest_init();
 663 }
 664
 665 /* Call all constructor functions linked into the kernel. */
 666 static void __init do_ctors(void)
 667 {
 668 #ifdef CONFIG_CONSTRUCTORS
 669         ctor_fn_t *fn = (ctor_fn_t *) __ctors_start;
 670
 671         for (; fn < (ctor_fn_t *) __ctors_end; fn++)
 672                 (*fn)();
 673 #endif
 674 }
 675
 676 bool initcall_debug;
 677 core_param(initcall_debug, initcall_debug, bool, 0644);
 678
 679 #ifdef CONFIG_KALLSYMS
 680 struct blacklist_entry {
 681         struct list_head next;
 682         char *buf;
 683 };
 684
 685 static __initdata_or_module LIST_HEAD(blacklisted_initcalls);
 686
 687 static int __init initcall_blacklist(char *str)
 688 {
 689         char *str_entry;
 690         struct blacklist_entry *entry;
 691
 692         /* str argument is a comma-separated list of functions */
 693         do {
 694                 str_entry = strsep(&str, ",");
 695                 if (str_entry) {
 696                         pr_debug("blacklisting initcall %s\n", str_entry);
 697                         entry = alloc_bootmem(sizeof(*entry));
 698                         entry->buf = alloc_bootmem(strlen(str_entry) + 1);
 699                         strcpy(entry->buf, str_entry);
 700                         list_add(&entry->next, &blacklisted_initcalls);
 701                 }
 702         } while (str_entry);
 703
 704         return 0;
 705 }
 706
 707 static bool __init_or_module initcall_blacklisted(initcall_t fn)
 708 {
 709         struct blacklist_entry *entry;
 710         char fn_name[KSYM_SYMBOL_LEN];
 711
 712         if (list_empty(&blacklisted_initcalls))
 713                 return false;
 714
 715         sprint_symbol_no_offset(fn_name, (unsigned long)fn);
 716
 717         list_for_each_entry(entry, &blacklisted_initcalls, next) {
 718                 if (!strcmp(fn_name, entry->buf)) {
 719                         pr_debug("initcall %s blacklisted\n", fn_name);
 720                         return true;
 721                 }
 722         }
 723
 724         return false;
 725 }
 726 #else
 727 static int __init initcall_blacklist(char *str)
 728 {
 729         pr_warn("initcall_blacklist requires CONFIG_KALLSYMS\n");
 730         return 0;
 731 }
 732
 733 static bool __init_or_module initcall_blacklisted(initcall_t fn)
 734 {
 735         return false;
 736 }
 737 #endif
 738 __setup("initcall_blacklist=", initcall_blacklist);
 739
 740 static int __init_or_module do_one_initcall_debug(initcall_t fn)
 741 {
 742         ktime_t calltime, delta, rettime;
 743         unsigned long long duration;
 744         int ret;
 745
 746         printk(KERN_DEBUG "calling  %pF @ %i\n", fn, task_pid_nr(current));
 747         calltime = ktime_get();
 748         ret = fn();
 749         rettime = ktime_get();
 750         delta = ktime_sub(rettime, calltime);
 751         duration = (unsigned long long) ktime_to_ns(delta) >> 10;
 752         printk(KERN_DEBUG "initcall %pF returned %d after %lld usecs\n",
 753                  fn, ret, duration);
 754
 755         return ret;
 756 }
 757
 758 int __init_or_module do_one_initcall(initcall_t fn)
 759 {
 760         int count = preempt_count();
 761         int ret;
 762         char msgbuf[64];
 763
 764         if (initcall_blacklisted(fn))
 765                 return -EPERM;
 766
 767         if (initcall_debug)
 768                 ret = do_one_initcall_debug(fn);
 769         else
 770                 ret = fn();
 771
 772         msgbuf[0] = 0;
 773
 774         if (preempt_count() != count) {
 775                 sprintf(msgbuf, "preemption imbalance ");
 776                 preempt_count_set(count);
 777         }
 778         if (irqs_disabled()) {
 779                 strlcat(msgbuf, "disabled interrupts ", sizeof(msgbuf));
 780                 local_irq_enable();
 781         }
 782         WARN(msgbuf[0], "initcall %pF returned with %s\n", fn, msgbuf);
 783
 784         return ret;
 785 }
 786
 787
 788 extern initcall_t __initcall_start[];
 789 extern initcall_t __initcall0_start[];
 790 extern initcall_t __initcall1_start[];
 791 extern initcall_t __initcall2_start[];
 792 extern initcall_t __initcall3_start[];
 793 extern initcall_t __initcall4_start[];
 794 extern initcall_t __initcall5_start[];
 795 extern initcall_t __initcall6_start[];
 796 extern initcall_t __initcall7_start[];
 797 extern initcall_t __initcall_end[];
 798
 799 static initcall_t *initcall_levels[] __initdata = {
 800         __initcall0_start,
 801         __initcall1_start,
 802         __initcall2_start,
 803         __initcall3_start,
 804         __initcall4_start,
 805         __initcall5_start,
 806         __initcall6_start,
 807         __initcall7_start,
 808         __initcall_end,
 809 };
 810
 811 /* Keep these in sync with initcalls in include/linux/init.h */
 812 static char *initcall_level_names[] __initdata = {
 813         "early",
 814         "core",
 815         "postcore",
 816         "arch",
 817         "subsys",
 818         "fs",
 819         "device",
 820         "late",
 821 };
 822
 823 static void __init do_initcall_level(int level)
 824 {
 825         initcall_t *fn;
 826
 827         strcpy(initcall_command_line, saved_command_line);
 828         parse_args(initcall_level_names[level],
 829                    initcall_command_line, __start___param,
 830                    __stop___param - __start___param,
 831                    level, level,
 832                    NULL, &repair_env_string);
 833
 834         for (fn = initcall_levels[level]; fn < initcall_levels[level+1]; fn++)
 835                 do_one_initcall(*fn);
 836 }
 837
 838 static void __init do_initcalls(void)
 839 {
 840         int level;
 841
 842         for (level = 0; level < ARRAY_SIZE(initcall_levels) - 1; level++)
 843                 do_initcall_level(level);
 844 }
 845
 846 /*
 847  * Ok, the machine is now initialized. None of the devices
 848  * have been touched yet, but the CPU subsystem is up and
 849  * running, and memory and process management works.
 850  *
 851  * Now we can finally start doing some real work..
 852  */
 853 static void __init do_basic_setup(void)
 854 {
 855         cpuset_init_smp();
 856         shmem_init();
 857         driver_init();
 858         init_irq_proc();
 859         do_ctors();
 860         usermodehelper_enable();
 861         do_initcalls();
 862         random_int_secret_init();
 863 }
 864
 865 static void __init do_pre_smp_initcalls(void)
 866 {
 867         initcall_t *fn;
 868
 869         for (fn = __initcall_start; fn < __initcall0_start; fn++)
 870                 do_one_initcall(*fn);
 871 }
 872
 873 /*
 874  * This function requests modules which should be loaded by default and is
 875  * called twice right after initrd is mounted and right before init is
 876  * exec'd.  If such modules are on either initrd or rootfs, they will be
 877  * loaded before control is passed to userland.
 878  */
 879 void __init load_default_modules(void)
 880 {
 881         load_default_elevator_module();
 882 }
 883
 884 static int run_init_process(const char *init_filename)
 885 {
 886         argv_init[0] = init_filename;
 887         return do_execve(getname_kernel(init_filename),
 888                 (const char __user *const __user *)argv_init,
 889                 (const char __user *const __user *)envp_init);
 890 }
 891
 892 static int try_to_run_init_process(const char *init_filename)
 893 {
 894         int ret;
 895
 896         ret = run_init_process(init_filename);
 897
 898         if (ret && ret != -ENOENT) {
 899                 pr_err("Starting init: %s exists but couldn't execute it (error %d)\n",
 900                        init_filename, ret);
 901         }
 902
 903         return ret;
 904 }
 905
 906 static noinline void __init kernel_init_freeable(void);
 907
 908 #ifdef CONFIG_DEBUG_RODATA
 909 static bool rodata_enabled = true;
 910 static int __init set_debug_rodata(char *str)
 911 {
 912         return strtobool(str, &rodata_enabled);
 913 }
 914 __setup("rodata=", set_debug_rodata);
 915
 916 static void mark_readonly(void)
 917 {
 918         if (rodata_enabled)
 919                 mark_rodata_ro();
 920         else
 921                 pr_info("Kernel memory protection disabled.\n");
 922 }
 923 #else
 924 static inline void mark_readonly(void)
 925 {
 926         pr_warn("This architecture does not have kernel memory protection.\n");
 927 }
 928 #endif
 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_readonly();
 939         system_state = SYSTEM_RUNNING;
 940         numa_default_policy();
 941
 942         flush_delayed_fput();
 943
 944         rcu_end_inkernel_boot();
 945
 946         if (ramdisk_execute_command) {
 947                 ret = run_init_process(ramdisk_execute_command);
 948                 if (!ret)
 949                         return 0;
 950                 pr_err("Failed to execute %s (error %d)\n",
 951                        ramdisk_execute_command, ret);
 952         }
 953
 954         /*
 955          * We try each of these until one succeeds.
 956          *
 957          * The Bourne shell can be used instead of init if we are
 958          * trying to recover a really broken machine.
 959          */
 960         if (execute_command) {
 961                 ret = run_init_process(execute_command);
 962                 if (!ret)
 963                         return 0;
 964                 panic("Requested init %s failed (error %d).",
 965                       execute_command, ret);
 966         }
 967         if (!try_to_run_init_process("/sbin/init") ||
 968             !try_to_run_init_process("/etc/init") ||
 969             !try_to_run_init_process("/bin/init") ||
 970             !try_to_run_init_process("/bin/sh"))
 971                 return 0;
 972
 973         panic("No working init found.  Try passing init= option to kernel. "
 974               "See Linux Documentation/init.txt for guidance.");
 975 }
 976
 977 static noinline void __init kernel_init_freeable(void)
 978 {
 979         /*
 980          * Wait until kthreadd is all set-up.
 981          */
 982         wait_for_completion(&kthreadd_done);
 983
 984         /* Now the scheduler is fully set up and can do blocking allocations */
 985         gfp_allowed_mask = __GFP_BITS_MASK;
 986
 987         /*
 988          * init can allocate pages on any node
 989          */
 990         set_mems_allowed(node_states[N_MEMORY]);
 991         /*
 992          * init can run on any cpu.
 993          */
 994         set_cpus_allowed_ptr(current, cpu_all_mask);
 995
 996         cad_pid = task_pid(current);
 997
 998         smp_prepare_cpus(setup_max_cpus);
 999
1000         do_pre_smp_initcalls();
1001         lockup_detector_init();
1002
1003         smp_init();
1004         sched_init_smp();
1005
1006         page_alloc_init_late();
1007
1008         do_basic_setup();
1009
1010         /* Open the /dev/console on the rootfs, this should never fail */
1011         if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0)
1012                 pr_err("Warning: unable to open an initial console.\n");
1013
1014         (void) sys_dup(0);
1015         (void) sys_dup(0);
1016         /*
1017          * check if there is an early userspace init.  If yes, let it do all
1018          * the work
1019          */
1020
1021         if (!ramdisk_execute_command)
1022                 ramdisk_execute_command = "/init";
1023
1024         if (sys_access((const char __user *) ramdisk_execute_command, 0) != 0) {
1025                 ramdisk_execute_command = NULL;
1026                 prepare_namespace();
1027         }
1028
1029         /*
1030          * Ok, we have completed the initial bootup, and
1031          * we're essentially up and running. Get rid of the
1032          * initmem segments and start the user-mode stuff..
1033          *
1034          * rootfs is available now, try loading the public keys
1035          * and default modules
1036          */
1037
1038         integrity_load_keys();
1039         load_default_modules();
1040 }