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/extable.h>
  16 #include <linux/module.h>
  17 #include <linux/proc_fs.h>
  18 #include <linux/binfmts.h>
  19 #include <linux/kernel.h>
  20 #include <linux/syscalls.h>
  21 #include <linux/stackprotector.h>
  22 #include <linux/string.h>
  23 #include <linux/ctype.h>
  24 #include <linux/delay.h>
  25 #include <linux/ioport.h>
  26 #include <linux/init.h>
  27 #include <linux/initrd.h>
  28 #include <linux/bootmem.h>
  29 #include <linux/acpi.h>
  30 #include <linux/console.h>
  31 #include <linux/nmi.h>
  32 #include <linux/percpu.h>
  33 #include <linux/kmod.h>
  34 #include <linux/vmalloc.h>
  35 #include <linux/kernel_stat.h>
  36 #include <linux/start_kernel.h>
  37 #include <linux/security.h>
  38 #include <linux/smp.h>
  39 #include <linux/profile.h>
  40 #include <linux/rcupdate.h>
  41 #include <linux/moduleparam.h>
  42 #include <linux/kallsyms.h>
  43 #include <linux/writeback.h>
  44 #include <linux/cpu.h>
  45 #include <linux/cpuset.h>
  46 #include <linux/cgroup.h>
  47 #include <linux/efi.h>
  48 #include <linux/tick.h>
  49 #include <linux/sched/isolation.h>
  50 #include <linux/interrupt.h>
  51 #include <linux/taskstats_kern.h>
  52 #include <linux/delayacct.h>
  53 #include <linux/unistd.h>
  54 #include <linux/utsname.h>
  55 #include <linux/rmap.h>
  56 #include <linux/mempolicy.h>
  57 #include <linux/key.h>
  58 #include <linux/buffer_head.h>
  59 #include <linux/page_ext.h>
  60 #include <linux/debug_locks.h>
  61 #include <linux/debugobjects.h>
  62 #include <linux/lockdep.h>
  63 #include <linux/kmemleak.h>
  64 #include <linux/pid_namespace.h>
  65 #include <linux/device.h>
  66 #include <linux/kthread.h>
  67 #include <linux/sched.h>
  68 #include <linux/sched/init.h>
  69 #include <linux/signal.h>
  70 #include <linux/idr.h>
  71 #include <linux/kgdb.h>
  72 #include <linux/ftrace.h>
  73 #include <linux/async.h>
  74 #include <linux/sfi.h>
  75 #include <linux/shmem_fs.h>
  76 #include <linux/slab.h>
  77 #include <linux/perf_event.h>
  78 #include <linux/ptrace.h>
  79 #include <linux/pti.h>
  80 #include <linux/blkdev.h>
  81 #include <linux/elevator.h>
  82 #include <linux/sched_clock.h>
  83 #include <linux/sched/task.h>
  84 #include <linux/sched/task_stack.h>
  85 #include <linux/context_tracking.h>
  86 #include <linux/random.h>
  87 #include <linux/list.h>
  88 #include <linux/integrity.h>
  89 #include <linux/proc_ns.h>
  90 #include <linux/io.h>
  91 #include <linux/cache.h>
  92 #include <linux/rodata_test.h>
  93 #include <linux/jump_label.h>
  94 #include <linux/mem_encrypt.h>
  95
  96 #include <asm/io.h>
  97 #include <asm/bugs.h>
  98 #include <asm/setup.h>
  99 #include <asm/sections.h>
 100 #include <asm/cacheflush.h>
 101
 102 #define CREATE_TRACE_POINTS
 103 #include <trace/events/initcall.h>
 104
 105 static int kernel_init(void *);
 106
 107 extern void init_IRQ(void);
 108 extern void fork_init(void);
 109 extern void radix_tree_init(void);
 110
 111 /*
 112  * Debug helper: via this flag we know that we are in 'early bootup code'
 113  * where only the boot processor is running with IRQ disabled.  This means
 114  * two things - IRQ must not be enabled before the flag is cleared and some
 115  * operations which are not allowed with IRQ disabled are allowed while the
 116  * flag is set.
 117  */
 118 bool early_boot_irqs_disabled __read_mostly;
 119
 120 enum system_states system_state __read_mostly;
 121 EXPORT_SYMBOL(system_state);
 122
 123 /*
 124  * Boot command-line arguments
 125  */
 126 #define MAX_INIT_ARGS CONFIG_INIT_ENV_ARG_LIMIT
 127 #define MAX_INIT_ENVS CONFIG_INIT_ENV_ARG_LIMIT
 128
 129 extern void time_init(void);
 130 /* Default late time init is NULL. archs can override this later. */
 131 void (*__initdata late_time_init)(void);
 132
 133 /* Untouched command line saved by arch-specific code. */
 134 char __initdata boot_command_line[COMMAND_LINE_SIZE];
 135 /* Untouched saved command line (eg. for /proc) */
 136 char *saved_command_line;
 137 /* Command line for parameter parsing */
 138 static char *static_command_line;
 139 /* Command line for per-initcall parameter parsing */
 140 static char *initcall_command_line;
 141
 142 static char *execute_command;
 143 static char *ramdisk_execute_command;
 144
 145 /*
 146  * Used to generate warnings if static_key manipulation functions are used
 147  * before jump_label_init is called.
 148  */
 149 bool static_key_initialized __read_mostly;
 150 EXPORT_SYMBOL_GPL(static_key_initialized);
 151
 152 /*
 153  * If set, this is an indication to the drivers that reset the underlying
 154  * device before going ahead with the initialization otherwise driver might
 155  * rely on the BIOS and skip the reset operation.
 156  *
 157  * This is useful if kernel is booting in an unreliable environment.
 158  * For ex. kdump situation where previous kernel has crashed, BIOS has been
 159  * skipped and devices will be in unknown state.
 160  */
 161 unsigned int reset_devices;
 162 EXPORT_SYMBOL(reset_devices);
 163
 164 static int __init set_reset_devices(char *str)
 165 {
 166         reset_devices = 1;
 167         return 1;
 168 }
 169
 170 __setup("reset_devices", set_reset_devices);
 171
 172 static const char *argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
 173 const char *envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, };
 174 static const char *panic_later, *panic_param;
 175
 176 extern const struct obs_kernel_param __setup_start[], __setup_end[];
 177
 178 static bool __init obsolete_checksetup(char *line)
 179 {
 180         const struct obs_kernel_param *p;
 181         bool had_early_param = false;
 182
 183         p = __setup_start;
 184         do {
 185                 int n = strlen(p->str);
 186                 if (parameqn(line, p->str, n)) {
 187                         if (p->early) {
 188                                 /* Already done in parse_early_param?
 189                                  * (Needs exact match on param part).
 190                                  * Keep iterating, as we can have early
 191                                  * params and __setups of same names 8( */
 192                                 if (line[n] == '\0' || line[n] == '=')
 193                                         had_early_param = true;
 194                         } else if (!p->setup_func) {
 195                                 pr_warn("Parameter %s is obsolete, ignored\n",
 196                                         p->str);
 197                                 return true;
 198                         } else if (p->setup_func(line + n))
 199                                 return true;
 200                 }
 201                 p++;
 202         } while (p < __setup_end);
 203
 204         return had_early_param;
 205 }
 206
 207 /*
 208  * This should be approx 2 Bo*oMips to start (note initial shift), and will
 209  * still work even if initially too large, it will just take slightly longer
 210  */
 211 unsigned long loops_per_jiffy = (1<<12);
 212 EXPORT_SYMBOL(loops_per_jiffy);
 213
 214 static int __init debug_kernel(char *str)
 215 {
 216         console_loglevel = CONSOLE_LOGLEVEL_DEBUG;
 217         return 0;
 218 }
 219
 220 static int __init quiet_kernel(char *str)
 221 {
 222         console_loglevel = CONSOLE_LOGLEVEL_QUIET;
 223         return 0;
 224 }
 225
 226 early_param("debug", debug_kernel);
 227 early_param("quiet", quiet_kernel);
 228
 229 static int __init loglevel(char *str)
 230 {
 231         int newlevel;
 232
 233         /*
 234          * Only update loglevel value when a correct setting was passed,
 235          * to prevent blind crashes (when loglevel being set to 0) that
 236          * are quite hard to debug
 237          */
 238         if (get_option(&str, &newlevel)) {
 239                 console_loglevel = newlevel;
 240                 return 0;
 241         }
 242
 243         return -EINVAL;
 244 }
 245
 246 early_param("loglevel", loglevel);
 247
 248 /* Change NUL term back to "=", to make "param" the whole string. */
 249 static int __init repair_env_string(char *param, char *val,
 250                                     const char *unused, void *arg)
 251 {
 252         if (val) {
 253                 /* param=val or param="val"? */
 254                 if (val == param+strlen(param)+1)
 255                         val[-1] = '=';
 256                 else if (val == param+strlen(param)+2) {
 257                         val[-2] = '=';
 258                         memmove(val-1, val, strlen(val)+1);
 259                         val--;
 260                 } else
 261                         BUG();
 262         }
 263         return 0;
 264 }
 265
 266 /* Anything after -- gets handed straight to init. */
 267 static int __init set_init_arg(char *param, char *val,
 268                                const char *unused, void *arg)
 269 {
 270         unsigned int i;
 271
 272         if (panic_later)
 273                 return 0;
 274
 275         repair_env_string(param, val, unused, NULL);
 276
 277         for (i = 0; argv_init[i]; i++) {
 278                 if (i == MAX_INIT_ARGS) {
 279                         panic_later = "init";
 280                         panic_param = param;
 281                         return 0;
 282                 }
 283         }
 284         argv_init[i] = param;
 285         return 0;
 286 }
 287
 288 /*
 289  * Unknown boot options get handed to init, unless they look like
 290  * unused parameters (modprobe will find them in /proc/cmdline).
 291  */
 292 static int __init unknown_bootoption(char *param, char *val,
 293                                      const char *unused, void *arg)
 294 {
 295         repair_env_string(param, val, unused, NULL);
 296
 297         /* Handle obsolete-style parameters */
 298         if (obsolete_checksetup(param))
 299                 return 0;
 300
 301         /* Unused module parameter. */
 302         if (strchr(param, '.') && (!val || strchr(param, '.') < val))
 303                 return 0;
 304
 305         if (panic_later)
 306                 return 0;
 307
 308         if (val) {
 309                 /* Environment option */
 310                 unsigned int i;
 311                 for (i = 0; envp_init[i]; i++) {
 312                         if (i == MAX_INIT_ENVS) {
 313                                 panic_later = "env";
 314                                 panic_param = param;
 315                         }
 316                         if (!strncmp(param, envp_init[i], val - param))
 317                                 break;
 318                 }
 319                 envp_init[i] = param;
 320         } else {
 321                 /* Command line option */
 322                 unsigned int i;
 323                 for (i = 0; argv_init[i]; i++) {
 324                         if (i == MAX_INIT_ARGS) {
 325                                 panic_later = "init";
 326                                 panic_param = param;
 327                         }
 328                 }
 329                 argv_init[i] = param;
 330         }
 331         return 0;
 332 }
 333
 334 static int __init init_setup(char *str)
 335 {
 336         unsigned int i;
 337
 338         execute_command = str;
 339         /*
 340          * In case LILO is going to boot us with default command line,
 341          * it prepends "auto" before the whole cmdline which makes
 342          * the shell think it should execute a script with such name.
 343          * So we ignore all arguments entered _before_ init=... [MJ]
 344          */
 345         for (i = 1; i < MAX_INIT_ARGS; i++)
 346                 argv_init[i] = NULL;
 347         return 1;
 348 }
 349 __setup("init=", init_setup);
 350
 351 static int __init rdinit_setup(char *str)
 352 {
 353         unsigned int i;
 354
 355         ramdisk_execute_command = str;
 356         /* See "auto" comment in init_setup */
 357         for (i = 1; i < MAX_INIT_ARGS; i++)
 358                 argv_init[i] = NULL;
 359         return 1;
 360 }
 361 __setup("rdinit=", rdinit_setup);
 362
 363 #ifndef CONFIG_SMP
 364 static const unsigned int setup_max_cpus = NR_CPUS;
 365 static inline void setup_nr_cpu_ids(void) { }
 366 static inline void smp_prepare_cpus(unsigned int maxcpus) { }
 367 #endif
 368
 369 /*
 370  * We need to store the untouched command line for future reference.
 371  * We also need to store the touched command line since the parameter
 372  * parsing is performed in place, and we should allow a component to
 373  * store reference of name/value for future reference.
 374  */
 375 static void __init setup_command_line(char *command_line)
 376 {
 377         saved_command_line =
 378                 memblock_virt_alloc(strlen(boot_command_line) + 1, 0);
 379         initcall_command_line =
 380                 memblock_virt_alloc(strlen(boot_command_line) + 1, 0);
 381         static_command_line = memblock_virt_alloc(strlen(command_line) + 1, 0);
 382         strcpy(saved_command_line, boot_command_line);
 383         strcpy(static_command_line, command_line);
 384 }
 385
 386 /*
 387  * We need to finalize in a non-__init function or else race conditions
 388  * between the root thread and the init thread may cause start_kernel to
 389  * be reaped by free_initmem before the root thread has proceeded to
 390  * cpu_idle.
 391  *
 392  * gcc-3.4 accidentally inlines this function, so use noinline.
 393  */
 394
 395 static __initdata DECLARE_COMPLETION(kthreadd_done);
 396
 397 static noinline void __ref rest_init(void)
 398 {
 399         struct task_struct *tsk;
 400         int pid;
 401
 402         rcu_scheduler_starting();
 403         /*
 404          * We need to spawn init first so that it obtains pid 1, however
 405          * the init task will end up wanting to create kthreads, which, if
 406          * we schedule it before we create kthreadd, will OOPS.
 407          */
 408         pid = kernel_thread(kernel_init, NULL, CLONE_FS);
 409         /*
 410          * Pin init on the boot CPU. Task migration is not properly working
 411          * until sched_init_smp() has been run. It will set the allowed
 412          * CPUs for init to the non isolated CPUs.
 413          */
 414         rcu_read_lock();
 415         tsk = find_task_by_pid_ns(pid, &init_pid_ns);
 416         set_cpus_allowed_ptr(tsk, cpumask_of(smp_processor_id()));
 417         rcu_read_unlock();
 418
 419         numa_default_policy();
 420         pid = kernel_thread(kthreadd, NULL, CLONE_FS | CLONE_FILES);
 421         rcu_read_lock();
 422         kthreadd_task = find_task_by_pid_ns(pid, &init_pid_ns);
 423         rcu_read_unlock();
 424
 425         /*
 426          * Enable might_sleep() and smp_processor_id() checks.
 427          * They cannot be enabled earlier because with CONFIG_PREEMPT=y
 428          * kernel_thread() would trigger might_sleep() splats. With
 429          * CONFIG_PREEMPT_VOLUNTARY=y the init task might have scheduled
 430          * already, but it's stuck on the kthreadd_done completion.
 431          */
 432         system_state = SYSTEM_SCHEDULING;
 433
 434         complete(&kthreadd_done);
 435
 436         /*
 437          * The boot idle thread must execute schedule()
 438          * at least once to get things moving:
 439          */
 440         schedule_preempt_disabled();
 441         /* Call into cpu_idle with preempt disabled */
 442         cpu_startup_entry(CPUHP_ONLINE);
 443 }
 444
 445 /* Check for early params. */
 446 static int __init do_early_param(char *param, char *val,
 447                                  const char *unused, void *arg)
 448 {
 449         const struct obs_kernel_param *p;
 450
 451         for (p = __setup_start; p < __setup_end; p++) {
 452                 if ((p->early && parameq(param, p->str)) ||
 453                     (strcmp(param, "console") == 0 &&
 454                      strcmp(p->str, "earlycon") == 0)
 455                 ) {
 456                         if (p->setup_func(val) != 0)
 457                                 pr_warn("Malformed early option '%s'\n", param);
 458                 }
 459         }
 460         /* We accept everything at this stage. */
 461         return 0;
 462 }
 463
 464 void __init parse_early_options(char *cmdline)
 465 {
 466         parse_args("early options", cmdline, NULL, 0, 0, 0, NULL,
 467                    do_early_param);
 468 }
 469
 470 /* Arch code calls this early on, or if not, just before other parsing. */
 471 void __init parse_early_param(void)
 472 {
 473         static int done __initdata;
 474         static char tmp_cmdline[COMMAND_LINE_SIZE] __initdata;
 475
 476         if (done)
 477                 return;
 478
 479         /* All fall through to do_early_param. */
 480         strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);
 481         parse_early_options(tmp_cmdline);
 482         done = 1;
 483 }
 484
 485 void __init __weak arch_post_acpi_subsys_init(void) { }
 486
 487 void __init __weak smp_setup_processor_id(void)
 488 {
 489 }
 490
 491 # if THREAD_SIZE >= PAGE_SIZE
 492 void __init __weak thread_stack_cache_init(void)
 493 {
 494 }
 495 #endif
 496
 497 void __init __weak mem_encrypt_init(void) { }
 498
 499 bool initcall_debug;
 500 core_param(initcall_debug, initcall_debug, bool, 0644);
 501
 502 #ifdef TRACEPOINTS_ENABLED
 503 static void __init initcall_debug_enable(void);
 504 #else
 505 static inline void initcall_debug_enable(void)
 506 {
 507 }
 508 #endif
 509
 510 /*
 511  * Set up kernel memory allocators
 512  */
 513 static void __init mm_init(void)
 514 {
 515         /*
 516          * page_ext requires contiguous pages,
 517          * bigger than MAX_ORDER unless SPARSEMEM.
 518          */
 519         page_ext_init_flatmem();
 520         mem_init();
 521         kmem_cache_init();
 522         pgtable_init();
 523         vmalloc_init();
 524         ioremap_huge_init();
 525         /* Should be run before the first non-init thread is created */
 526         init_espfix_bsp();
 527         /* Should be run after espfix64 is set up. */
 528         pti_init();
 529 }
 530
 531 asmlinkage __visible void __init start_kernel(void)
 532 {
 533         char *command_line;
 534         char *after_dashes;
 535
 536         set_task_stack_end_magic(&init_task);
 537         smp_setup_processor_id();
 538         debug_objects_early_init();
 539
 540         cgroup_init_early();
 541
 542         local_irq_disable();
 543         early_boot_irqs_disabled = true;
 544
 545         /*
 546          * Interrupts are still disabled. Do necessary setups, then
 547          * enable them.
 548          */
 549         boot_cpu_init();
 550         page_address_init();
 551         pr_notice("%s", linux_banner);
 552         setup_arch(&command_line);
 553         /*
 554          * Set up the the initial canary and entropy after arch
 555          * and after adding latent and command line entropy.
 556          */
 557         add_latent_entropy();
 558         add_device_randomness(command_line, strlen(command_line));
 559         boot_init_stack_canary();
 560         mm_init_cpumask(&init_mm);
 561         setup_command_line(command_line);
 562         setup_nr_cpu_ids();
 563         setup_per_cpu_areas();
 564         boot_cpu_state_init();
 565         smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */
 566
 567         build_all_zonelists(NULL);
 568         page_alloc_init();
 569
 570         pr_notice("Kernel command line: %s\n", boot_command_line);
 571         parse_early_param();
 572         after_dashes = parse_args("Booting kernel",
 573                                   static_command_line, __start___param,
 574                                   __stop___param - __start___param,
 575                                   -1, -1, NULL, &unknown_bootoption);
 576         if (!IS_ERR_OR_NULL(after_dashes))
 577                 parse_args("Setting init args", after_dashes, NULL, 0, -1, -1,
 578                            NULL, set_init_arg);
 579
 580         jump_label_init();
 581
 582         /*
 583          * These use large bootmem allocations and must precede
 584          * kmem_cache_init()
 585          */
 586         setup_log_buf(0);
 587         vfs_caches_init_early();
 588         sort_main_extable();
 589         trap_init();
 590         mm_init();
 591
 592         ftrace_init();
 593
 594         /* trace_printk can be enabled here */
 595         early_trace_init();
 596
 597         /*
 598          * Set up the scheduler prior starting any interrupts (such as the
 599          * timer interrupt). Full topology setup happens at smp_init()
 600          * time - but meanwhile we still have a functioning scheduler.
 601          */
 602         sched_init();
 603         /*
 604          * Disable preemption - early bootup scheduling is extremely
 605          * fragile until we cpu_idle() for the first time.
 606          */
 607         preempt_disable();
 608         if (WARN(!irqs_disabled(),
 609                  "Interrupts were enabled *very* early, fixing it\n"))
 610                 local_irq_disable();
 611         radix_tree_init();
 612
 613         /*
 614          * Set up housekeeping before setting up workqueues to allow the unbound
 615          * workqueue to take non-housekeeping into account.
 616          */
 617         housekeeping_init();
 618
 619         /*
 620          * Allow workqueue creation and work item queueing/cancelling
 621          * early.  Work item execution depends on kthreads and starts after
 622          * workqueue_init().
 623          */
 624         workqueue_init_early();
 625
 626         rcu_init();
 627
 628         /* Trace events are available after this */
 629         trace_init();
 630
 631         if (initcall_debug)
 632                 initcall_debug_enable();
 633
 634         context_tracking_init();
 635         /* init some links before init_ISA_irqs() */
 636         early_irq_init();
 637         init_IRQ();
 638         tick_init();
 639         rcu_init_nohz();
 640         init_timers();
 641         hrtimers_init();
 642         softirq_init();
 643         timekeeping_init();
 644         time_init();
 645         sched_clock_postinit();
 646         printk_safe_init();
 647         perf_event_init();
 648         profile_init();
 649         call_function_init();
 650         WARN(!irqs_disabled(), "Interrupts were enabled early\n");
 651         early_boot_irqs_disabled = false;
 652         local_irq_enable();
 653
 654         kmem_cache_init_late();
 655
 656         /*
 657          * HACK ALERT! This is early. We're enabling the console before
 658          * we've done PCI setups etc, and console_init() must be aware of
 659          * this. But we do want output early, in case something goes wrong.
 660          */
 661         console_init();
 662         if (panic_later)
 663                 panic("Too many boot %s vars at `%s'", panic_later,
 664                       panic_param);
 665
 666         lockdep_info();
 667
 668         /*
 669          * Need to run this when irqs are enabled, because it wants
 670          * to self-test [hard/soft]-irqs on/off lock inversion bugs
 671          * too:
 672          */
 673         locking_selftest();
 674
 675         /*
 676          * This needs to be called before any devices perform DMA
 677          * operations that might use the SWIOTLB bounce buffers. It will
 678          * mark the bounce buffers as decrypted so that their usage will
 679          * not cause "plain-text" data to be decrypted when accessed.
 680          */
 681         mem_encrypt_init();
 682
 683 #ifdef CONFIG_BLK_DEV_INITRD
 684         if (initrd_start && !initrd_below_start_ok &&
 685             page_to_pfn(virt_to_page((void *)initrd_start)) < min_low_pfn) {
 686                 pr_crit("initrd overwritten (0x%08lx < 0x%08lx) - disabling it.\n",
 687                     page_to_pfn(virt_to_page((void *)initrd_start)),
 688                     min_low_pfn);
 689                 initrd_start = 0;
 690         }
 691 #endif
 692         page_ext_init();
 693         kmemleak_init();
 694         debug_objects_mem_init();
 695         setup_per_cpu_pageset();
 696         numa_policy_init();
 697         acpi_early_init();
 698         if (late_time_init)
 699                 late_time_init();
 700         calibrate_delay();
 701         pid_idr_init();
 702         anon_vma_init();
 703 #ifdef CONFIG_X86
 704         if (efi_enabled(EFI_RUNTIME_SERVICES))
 705                 efi_enter_virtual_mode();
 706 #endif
 707         thread_stack_cache_init();
 708         cred_init();
 709         fork_init();
 710         proc_caches_init();
 711         uts_ns_init();
 712         buffer_init();
 713         key_init();
 714         security_init();
 715         dbg_late_init();
 716         vfs_caches_init();
 717         pagecache_init();
 718         signals_init();
 719         seq_file_init();
 720         proc_root_init();
 721         nsfs_init();
 722         cpuset_init();
 723         cgroup_init();
 724         taskstats_init_early();
 725         delayacct_init();
 726
 727         check_bugs();
 728
 729         acpi_subsystem_init();
 730         arch_post_acpi_subsys_init();
 731         sfi_init_late();
 732
 733         if (efi_enabled(EFI_RUNTIME_SERVICES)) {
 734                 efi_free_boot_services();
 735         }
 736
 737         /* Do the rest non-__init'ed, we're now alive */
 738         rest_init();
 739 }
 740
 741 /* Call all constructor functions linked into the kernel. */
 742 static void __init do_ctors(void)
 743 {
 744 #ifdef CONFIG_CONSTRUCTORS
 745         ctor_fn_t *fn = (ctor_fn_t *) __ctors_start;
 746
 747         for (; fn < (ctor_fn_t *) __ctors_end; fn++)
 748                 (*fn)();
 749 #endif
 750 }
 751
 752 #ifdef CONFIG_KALLSYMS
 753 struct blacklist_entry {
 754         struct list_head next;
 755         char *buf;
 756 };
 757
 758 static __initdata_or_module LIST_HEAD(blacklisted_initcalls);
 759
 760 static int __init initcall_blacklist(char *str)
 761 {
 762         char *str_entry;
 763         struct blacklist_entry *entry;
 764
 765         /* str argument is a comma-separated list of functions */
 766         do {
 767                 str_entry = strsep(&str, ",");
 768                 if (str_entry) {
 769                         pr_debug("blacklisting initcall %s\n", str_entry);
 770                         entry = alloc_bootmem(sizeof(*entry));
 771                         entry->buf = alloc_bootmem(strlen(str_entry) + 1);
 772                         strcpy(entry->buf, str_entry);
 773                         list_add(&entry->next, &blacklisted_initcalls);
 774                 }
 775         } while (str_entry);
 776
 777         return 0;
 778 }
 779
 780 static bool __init_or_module initcall_blacklisted(initcall_t fn)
 781 {
 782         struct blacklist_entry *entry;
 783         char fn_name[KSYM_SYMBOL_LEN];
 784         unsigned long addr;
 785
 786         if (list_empty(&blacklisted_initcalls))
 787                 return false;
 788
 789         addr = (unsigned long) dereference_function_descriptor(fn);
 790         sprint_symbol_no_offset(fn_name, addr);
 791
 792         /*
 793          * fn will be "function_name [module_name]" where [module_name] is not
 794          * displayed for built-in init functions.  Strip off the [module_name].
 795          */
 796         strreplace(fn_name, ' ', '\0');
 797
 798         list_for_each_entry(entry, &blacklisted_initcalls, next) {
 799                 if (!strcmp(fn_name, entry->buf)) {
 800                         pr_debug("initcall %s blacklisted\n", fn_name);
 801                         return true;
 802                 }
 803         }
 804
 805         return false;
 806 }
 807 #else
 808 static int __init initcall_blacklist(char *str)
 809 {
 810         pr_warn("initcall_blacklist requires CONFIG_KALLSYMS\n");
 811         return 0;
 812 }
 813
 814 static bool __init_or_module initcall_blacklisted(initcall_t fn)
 815 {
 816         return false;
 817 }
 818 #endif
 819 __setup("initcall_blacklist=", initcall_blacklist);
 820
 821 static __init_or_module void
 822 trace_initcall_start_cb(void *data, initcall_t fn)
 823 {
 824         ktime_t *calltime = (ktime_t *)data;
 825
 826         printk(KERN_DEBUG "calling  %pF @ %i\n", fn, task_pid_nr(current));
 827         *calltime = ktime_get();
 828 }
 829
 830 static __init_or_module void
 831 trace_initcall_finish_cb(void *data, initcall_t fn, int ret)
 832 {
 833         ktime_t *calltime = (ktime_t *)data;
 834         ktime_t delta, rettime;
 835         unsigned long long duration;
 836
 837         rettime = ktime_get();
 838         delta = ktime_sub(rettime, *calltime);
 839         duration = (unsigned long long) ktime_to_ns(delta) >> 10;
 840         printk(KERN_DEBUG "initcall %pF returned %d after %lld usecs\n",
 841                  fn, ret, duration);
 842 }
 843
 844 static ktime_t initcall_calltime;
 845
 846 #ifdef TRACEPOINTS_ENABLED
 847 static void __init initcall_debug_enable(void)
 848 {
 849         int ret;
 850
 851         ret = register_trace_initcall_start(trace_initcall_start_cb,
 852                                             &initcall_calltime);
 853         ret |= register_trace_initcall_finish(trace_initcall_finish_cb,
 854                                               &initcall_calltime);
 855         WARN(ret, "Failed to register initcall tracepoints\n");
 856 }
 857 # define do_trace_initcall_start        trace_initcall_start
 858 # define do_trace_initcall_finish       trace_initcall_finish
 859 #else
 860 static inline void do_trace_initcall_start(initcall_t fn)
 861 {
 862         if (!initcall_debug)
 863                 return;
 864         trace_initcall_start_cb(&initcall_calltime, fn);
 865 }
 866 static inline void do_trace_initcall_finish(initcall_t fn, int ret)
 867 {
 868         if (!initcall_debug)
 869                 return;
 870         trace_initcall_finish_cb(&initcall_calltime, fn, ret);
 871 }
 872 #endif /* !TRACEPOINTS_ENABLED */
 873
 874 int __init_or_module do_one_initcall(initcall_t fn)
 875 {
 876         int count = preempt_count();
 877         char msgbuf[64];
 878         int ret;
 879
 880         if (initcall_blacklisted(fn))
 881                 return -EPERM;
 882
 883         do_trace_initcall_start(fn);
 884         ret = fn();
 885         do_trace_initcall_finish(fn, ret);
 886
 887         msgbuf[0] = 0;
 888
 889         if (preempt_count() != count) {
 890                 sprintf(msgbuf, "preemption imbalance ");
 891                 preempt_count_set(count);
 892         }
 893         if (irqs_disabled()) {
 894                 strlcat(msgbuf, "disabled interrupts ", sizeof(msgbuf));
 895                 local_irq_enable();
 896         }
 897         WARN(msgbuf[0], "initcall %pF returned with %s\n", fn, msgbuf);
 898
 899         add_latent_entropy();
 900         return ret;
 901 }
 902
 903
 904 extern initcall_t __initcall_start[];
 905 extern initcall_t __initcall0_start[];
 906 extern initcall_t __initcall1_start[];
 907 extern initcall_t __initcall2_start[];
 908 extern initcall_t __initcall3_start[];
 909 extern initcall_t __initcall4_start[];
 910 extern initcall_t __initcall5_start[];
 911 extern initcall_t __initcall6_start[];
 912 extern initcall_t __initcall7_start[];
 913 extern initcall_t __initcall_end[];
 914
 915 static initcall_t *initcall_levels[] __initdata = {
 916         __initcall0_start,
 917         __initcall1_start,
 918         __initcall2_start,
 919         __initcall3_start,
 920         __initcall4_start,
 921         __initcall5_start,
 922         __initcall6_start,
 923         __initcall7_start,
 924         __initcall_end,
 925 };
 926
 927 /* Keep these in sync with initcalls in include/linux/init.h */
 928 static char *initcall_level_names[] __initdata = {
 929         "pure",
 930         "core",
 931         "postcore",
 932         "arch",
 933         "subsys",
 934         "fs",
 935         "device",
 936         "late",
 937 };
 938
 939 static void __init do_initcall_level(int level)
 940 {
 941         initcall_t *fn;
 942
 943         strcpy(initcall_command_line, saved_command_line);
 944         parse_args(initcall_level_names[level],
 945                    initcall_command_line, __start___param,
 946                    __stop___param - __start___param,
 947                    level, level,
 948                    NULL, &repair_env_string);
 949
 950         trace_initcall_level(initcall_level_names[level]);
 951         for (fn = initcall_levels[level]; fn < initcall_levels[level+1]; fn++)
 952                 do_one_initcall(*fn);
 953 }
 954
 955 static void __init do_initcalls(void)
 956 {
 957         int level;
 958
 959         for (level = 0; level < ARRAY_SIZE(initcall_levels) - 1; level++)
 960                 do_initcall_level(level);
 961 }
 962
 963 /*
 964  * Ok, the machine is now initialized. None of the devices
 965  * have been touched yet, but the CPU subsystem is up and
 966  * running, and memory and process management works.
 967  *
 968  * Now we can finally start doing some real work..
 969  */
 970 static void __init do_basic_setup(void)
 971 {
 972         cpuset_init_smp();
 973         shmem_init();
 974         driver_init();
 975         init_irq_proc();
 976         do_ctors();
 977         usermodehelper_enable();
 978         do_initcalls();
 979 }
 980
 981 static void __init do_pre_smp_initcalls(void)
 982 {
 983         initcall_t *fn;
 984
 985         trace_initcall_level("early");
 986         for (fn = __initcall_start; fn < __initcall0_start; fn++)
 987                 do_one_initcall(*fn);
 988 }
 989
 990 /*
 991  * This function requests modules which should be loaded by default and is
 992  * called twice right after initrd is mounted and right before init is
 993  * exec'd.  If such modules are on either initrd or rootfs, they will be
 994  * loaded before control is passed to userland.
 995  */
 996 void __init load_default_modules(void)
 997 {
 998         load_default_elevator_module();
 999 }
1000
1001 static int run_init_process(const char *init_filename)
1002 {
1003         argv_init[0] = init_filename;
1004         return do_execve(getname_kernel(init_filename),
1005                 (const char __user *const __user *)argv_init,
1006                 (const char __user *const __user *)envp_init);
1007 }
1008
1009 static int try_to_run_init_process(const char *init_filename)
1010 {
1011         int ret;
1012
1013         ret = run_init_process(init_filename);
1014
1015         if (ret && ret != -ENOENT) {
1016                 pr_err("Starting init: %s exists but couldn't execute it (error %d)\n",
1017                        init_filename, ret);
1018         }
1019
1020         return ret;
1021 }
1022
1023 static noinline void __init kernel_init_freeable(void);
1024
1025 #if defined(CONFIG_STRICT_KERNEL_RWX) || defined(CONFIG_STRICT_MODULE_RWX)
1026 bool rodata_enabled __ro_after_init = true;
1027 static int __init set_debug_rodata(char *str)
1028 {
1029         return strtobool(str, &rodata_enabled);
1030 }
1031 __setup("rodata=", set_debug_rodata);
1032 #endif
1033
1034 #ifdef CONFIG_STRICT_KERNEL_RWX
1035 static void mark_readonly(void)
1036 {
1037         if (rodata_enabled) {
1038                 /*
1039                  * load_module() results in W+X mappings, which are cleaned up
1040                  * with call_rcu_sched().  Let's make sure that queued work is
1041                  * flushed so that we don't hit false positives looking for
1042                  * insecure pages which are W+X.
1043                  */
1044                 rcu_barrier_sched();
1045                 mark_rodata_ro();
1046                 rodata_test();
1047         } else
1048                 pr_info("Kernel memory protection disabled.\n");
1049 }
1050 #else
1051 static inline void mark_readonly(void)
1052 {
1053         pr_warn("This architecture does not have kernel memory protection.\n");
1054 }
1055 #endif
1056
1057 static int __ref kernel_init(void *unused)
1058 {
1059         int ret;
1060
1061         kernel_init_freeable();
1062         /* need to finish all async __init code before freeing the memory */
1063         async_synchronize_full();
1064         ftrace_free_init_mem();
1065         jump_label_invalidate_initmem();
1066         free_initmem();
1067         mark_readonly();
1068         system_state = SYSTEM_RUNNING;
1069         numa_default_policy();
1070
1071         rcu_end_inkernel_boot();
1072
1073         if (ramdisk_execute_command) {
1074                 ret = run_init_process(ramdisk_execute_command);
1075                 if (!ret)
1076                         return 0;
1077                 pr_err("Failed to execute %s (error %d)\n",
1078                        ramdisk_execute_command, ret);
1079         }
1080
1081         /*
1082          * We try each of these until one succeeds.
1083          *
1084          * The Bourne shell can be used instead of init if we are
1085          * trying to recover a really broken machine.
1086          */
1087         if (execute_command) {
1088                 ret = run_init_process(execute_command);
1089                 if (!ret)
1090                         return 0;
1091                 panic("Requested init %s failed (error %d).",
1092                       execute_command, ret);
1093         }
1094         if (!try_to_run_init_process("/sbin/init") ||
1095             !try_to_run_init_process("/etc/init") ||
1096             !try_to_run_init_process("/bin/init") ||
1097             !try_to_run_init_process("/bin/sh"))
1098                 return 0;
1099
1100         panic("No working init found.  Try passing init= option to kernel. "
1101               "See Linux Documentation/admin-guide/init.rst for guidance.");
1102 }
1103
1104 static noinline void __init kernel_init_freeable(void)
1105 {
1106         /*
1107          * Wait until kthreadd is all set-up.
1108          */
1109         wait_for_completion(&kthreadd_done);
1110
1111         /* Now the scheduler is fully set up and can do blocking allocations */
1112         gfp_allowed_mask = __GFP_BITS_MASK;
1113
1114         /*
1115          * init can allocate pages on any node
1116          */
1117         set_mems_allowed(node_states[N_MEMORY]);
1118
1119         cad_pid = task_pid(current);
1120
1121         smp_prepare_cpus(setup_max_cpus);
1122
1123         workqueue_init();
1124
1125         init_mm_internals();
1126
1127         do_pre_smp_initcalls();
1128         lockup_detector_init();
1129
1130         smp_init();
1131         sched_init_smp();
1132
1133         page_alloc_init_late();
1134
1135         do_basic_setup();
1136
1137         /* Open the /dev/console on the rootfs, this should never fail */
1138         if (ksys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0)
1139                 pr_err("Warning: unable to open an initial console.\n");
1140
1141         (void) ksys_dup(0);
1142         (void) ksys_dup(0);
1143         /*
1144          * check if there is an early userspace init.  If yes, let it do all
1145          * the work
1146          */
1147
1148         if (!ramdisk_execute_command)
1149                 ramdisk_execute_command = "/init";
1150
1151         if (ksys_access((const char __user *)
1152                         ramdisk_execute_command, 0) != 0) {
1153                 ramdisk_execute_command = NULL;
1154                 prepare_namespace();
1155         }
1156
1157         /*
1158          * Ok, we have completed the initial bootup, and
1159          * we're essentially up and running. Get rid of the
1160          * initmem segments and start the user-mode stuff..
1161          *
1162          * rootfs is available now, try loading the public keys
1163          * and default modules
1164          */
1165
1166         integrity_load_keys();
1167         load_default_modules();
1168 }