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/memblock.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 radix_tree_init(void);
 109
 110 /*
 111  * Debug helper: via this flag we know that we are in 'early bootup code'
 112  * where only the boot processor is running with IRQ disabled.  This means
 113  * two things - IRQ must not be enabled before the flag is cleared and some
 114  * operations which are not allowed with IRQ disabled are allowed while the
 115  * flag is set.
 116  */
 117 bool early_boot_irqs_disabled __read_mostly;
 118
 119 enum system_states system_state __read_mostly;
 120 EXPORT_SYMBOL(system_state);
 121
 122 /*
 123  * Boot command-line arguments
 124  */
 125 #define MAX_INIT_ARGS CONFIG_INIT_ENV_ARG_LIMIT
 126 #define MAX_INIT_ENVS CONFIG_INIT_ENV_ARG_LIMIT
 127
 128 extern void time_init(void);
 129 /* Default late time init is NULL. archs can override this later. */
 130 void (*__initdata late_time_init)(void);
 131
 132 /* Untouched command line saved by arch-specific code. */
 133 char __initdata boot_command_line[COMMAND_LINE_SIZE];
 134 /* Untouched saved command line (eg. for /proc) */
 135 char *saved_command_line;
 136 /* Command line for parameter parsing */
 137 static char *static_command_line;
 138 /* Command line for per-initcall parameter parsing */
 139 static char *initcall_command_line;
 140
 141 static char *execute_command;
 142 static char *ramdisk_execute_command;
 143
 144 /*
 145  * Used to generate warnings if static_key manipulation functions are used
 146  * before jump_label_init is called.
 147  */
 148 bool static_key_initialized __read_mostly;
 149 EXPORT_SYMBOL_GPL(static_key_initialized);
 150
 151 /*
 152  * If set, this is an indication to the drivers that reset the underlying
 153  * device before going ahead with the initialization otherwise driver might
 154  * rely on the BIOS and skip the reset operation.
 155  *
 156  * This is useful if kernel is booting in an unreliable environment.
 157  * For ex. kdump situation where previous kernel has crashed, BIOS has been
 158  * skipped and devices will be in unknown state.
 159  */
 160 unsigned int reset_devices;
 161 EXPORT_SYMBOL(reset_devices);
 162
 163 static int __init set_reset_devices(char *str)
 164 {
 165         reset_devices = 1;
 166         return 1;
 167 }
 168
 169 __setup("reset_devices", set_reset_devices);
 170
 171 static const char *argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
 172 const char *envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, };
 173 static const char *panic_later, *panic_param;
 174
 175 extern const struct obs_kernel_param __setup_start[], __setup_end[];
 176
 177 static bool __init obsolete_checksetup(char *line)
 178 {
 179         const struct obs_kernel_param *p;
 180         bool had_early_param = false;
 181
 182         p = __setup_start;
 183         do {
 184                 int n = strlen(p->str);
 185                 if (parameqn(line, p->str, n)) {
 186                         if (p->early) {
 187                                 /* Already done in parse_early_param?
 188                                  * (Needs exact match on param part).
 189                                  * Keep iterating, as we can have early
 190                                  * params and __setups of same names 8( */
 191                                 if (line[n] == '\0' || line[n] == '=')
 192                                         had_early_param = true;
 193                         } else if (!p->setup_func) {
 194                                 pr_warn("Parameter %s is obsolete, ignored\n",
 195                                         p->str);
 196                                 return true;
 197                         } else if (p->setup_func(line + n))
 198                                 return true;
 199                 }
 200                 p++;
 201         } while (p < __setup_end);
 202
 203         return had_early_param;
 204 }
 205
 206 /*
 207  * This should be approx 2 Bo*oMips to start (note initial shift), and will
 208  * still work even if initially too large, it will just take slightly longer
 209  */
 210 unsigned long loops_per_jiffy = (1<<12);
 211 EXPORT_SYMBOL(loops_per_jiffy);
 212
 213 static int __init debug_kernel(char *str)
 214 {
 215         console_loglevel = CONSOLE_LOGLEVEL_DEBUG;
 216         return 0;
 217 }
 218
 219 static int __init quiet_kernel(char *str)
 220 {
 221         console_loglevel = CONSOLE_LOGLEVEL_QUIET;
 222         return 0;
 223 }
 224
 225 early_param("debug", debug_kernel);
 226 early_param("quiet", quiet_kernel);
 227
 228 static int __init loglevel(char *str)
 229 {
 230         int newlevel;
 231
 232         /*
 233          * Only update loglevel value when a correct setting was passed,
 234          * to prevent blind crashes (when loglevel being set to 0) that
 235          * are quite hard to debug
 236          */
 237         if (get_option(&str, &newlevel)) {
 238                 console_loglevel = newlevel;
 239                 return 0;
 240         }
 241
 242         return -EINVAL;
 243 }
 244
 245 early_param("loglevel", loglevel);
 246
 247 /* Change NUL term back to "=", to make "param" the whole string. */
 248 static int __init repair_env_string(char *param, char *val,
 249                                     const char *unused, void *arg)
 250 {
 251         if (val) {
 252                 /* param=val or param="val"? */
 253                 if (val == param+strlen(param)+1)
 254                         val[-1] = '=';
 255                 else if (val == param+strlen(param)+2) {
 256                         val[-2] = '=';
 257                         memmove(val-1, val, strlen(val)+1);
 258                         val--;
 259                 } else
 260                         BUG();
 261         }
 262         return 0;
 263 }
 264
 265 /* Anything after -- gets handed straight to init. */
 266 static int __init set_init_arg(char *param, char *val,
 267                                const char *unused, void *arg)
 268 {
 269         unsigned int i;
 270
 271         if (panic_later)
 272                 return 0;
 273
 274         repair_env_string(param, val, unused, NULL);
 275
 276         for (i = 0; argv_init[i]; i++) {
 277                 if (i == MAX_INIT_ARGS) {
 278                         panic_later = "init";
 279                         panic_param = param;
 280                         return 0;
 281                 }
 282         }
 283         argv_init[i] = param;
 284         return 0;
 285 }
 286
 287 /*
 288  * Unknown boot options get handed to init, unless they look like
 289  * unused parameters (modprobe will find them in /proc/cmdline).
 290  */
 291 static int __init unknown_bootoption(char *param, char *val,
 292                                      const char *unused, void *arg)
 293 {
 294         repair_env_string(param, val, unused, NULL);
 295
 296         /* Handle obsolete-style parameters */
 297         if (obsolete_checksetup(param))
 298                 return 0;
 299
 300         /* Unused module parameter. */
 301         if (strchr(param, '.') && (!val || strchr(param, '.') < val))
 302                 return 0;
 303
 304         if (panic_later)
 305                 return 0;
 306
 307         if (val) {
 308                 /* Environment option */
 309                 unsigned int i;
 310                 for (i = 0; envp_init[i]; i++) {
 311                         if (i == MAX_INIT_ENVS) {
 312                                 panic_later = "env";
 313                                 panic_param = param;
 314                         }
 315                         if (!strncmp(param, envp_init[i], val - param))
 316                                 break;
 317                 }
 318                 envp_init[i] = param;
 319         } else {
 320                 /* Command line option */
 321                 unsigned int i;
 322                 for (i = 0; argv_init[i]; i++) {
 323                         if (i == MAX_INIT_ARGS) {
 324                                 panic_later = "init";
 325                                 panic_param = param;
 326                         }
 327                 }
 328                 argv_init[i] = param;
 329         }
 330         return 0;
 331 }
 332
 333 static int __init init_setup(char *str)
 334 {
 335         unsigned int i;
 336
 337         execute_command = str;
 338         /*
 339          * In case LILO is going to boot us with default command line,
 340          * it prepends "auto" before the whole cmdline which makes
 341          * the shell think it should execute a script with such name.
 342          * So we ignore all arguments entered _before_ init=... [MJ]
 343          */
 344         for (i = 1; i < MAX_INIT_ARGS; i++)
 345                 argv_init[i] = NULL;
 346         return 1;
 347 }
 348 __setup("init=", init_setup);
 349
 350 static int __init rdinit_setup(char *str)
 351 {
 352         unsigned int i;
 353
 354         ramdisk_execute_command = str;
 355         /* See "auto" comment in init_setup */
 356         for (i = 1; i < MAX_INIT_ARGS; i++)
 357                 argv_init[i] = NULL;
 358         return 1;
 359 }
 360 __setup("rdinit=", rdinit_setup);
 361
 362 #ifndef CONFIG_SMP
 363 static const unsigned int setup_max_cpus = NR_CPUS;
 364 static inline void setup_nr_cpu_ids(void) { }
 365 static inline void smp_prepare_cpus(unsigned int maxcpus) { }
 366 #endif
 367
 368 /*
 369  * We need to store the untouched command line for future reference.
 370  * We also need to store the touched command line since the parameter
 371  * parsing is performed in place, and we should allow a component to
 372  * store reference of name/value for future reference.
 373  */
 374 static void __init setup_command_line(char *command_line)
 375 {
 376         saved_command_line =
 377                 memblock_alloc(strlen(boot_command_line) + 1, SMP_CACHE_BYTES);
 378         initcall_command_line =
 379                 memblock_alloc(strlen(boot_command_line) + 1, SMP_CACHE_BYTES);
 380         static_command_line = memblock_alloc(strlen(command_line) + 1,
 381                                              SMP_CACHE_BYTES);
 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 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         debug_objects_mem_init();
 524         vmalloc_init();
 525         ioremap_huge_init();
 526         /* Should be run before the first non-init thread is created */
 527         init_espfix_bsp();
 528         /* Should be run after espfix64 is set up. */
 529         pti_init();
 530 }
 531
 532 void __init __weak arch_call_rest_init(void)
 533 {
 534         rest_init();
 535 }
 536
 537 asmlinkage __visible void __init start_kernel(void)
 538 {
 539         char *command_line;
 540         char *after_dashes;
 541
 542         set_task_stack_end_magic(&init_task);
 543         smp_setup_processor_id();
 544         debug_objects_early_init();
 545
 546         cgroup_init_early();
 547
 548         local_irq_disable();
 549         early_boot_irqs_disabled = true;
 550
 551         /*
 552          * Interrupts are still disabled. Do necessary setups, then
 553          * enable them.
 554          */
 555         boot_cpu_init();
 556         page_address_init();
 557         pr_notice("%s", linux_banner);
 558         setup_arch(&command_line);
 559         /*
 560          * Set up the the initial canary and entropy after arch
 561          * and after adding latent and command line entropy.
 562          */
 563         add_latent_entropy();
 564         add_device_randomness(command_line, strlen(command_line));
 565         boot_init_stack_canary();
 566         mm_init_cpumask(&init_mm);
 567         setup_command_line(command_line);
 568         setup_nr_cpu_ids();
 569         setup_per_cpu_areas();
 570         smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */
 571         boot_cpu_hotplug_init();
 572
 573         build_all_zonelists(NULL);
 574         page_alloc_init();
 575
 576         pr_notice("Kernel command line: %s\n", boot_command_line);
 577         parse_early_param();
 578         after_dashes = parse_args("Booting kernel",
 579                                   static_command_line, __start___param,
 580                                   __stop___param - __start___param,
 581                                   -1, -1, NULL, &unknown_bootoption);
 582         if (!IS_ERR_OR_NULL(after_dashes))
 583                 parse_args("Setting init args", after_dashes, NULL, 0, -1, -1,
 584                            NULL, set_init_arg);
 585
 586         jump_label_init();
 587
 588         /*
 589          * These use large bootmem allocations and must precede
 590          * kmem_cache_init()
 591          */
 592         setup_log_buf(0);
 593         vfs_caches_init_early();
 594         sort_main_extable();
 595         trap_init();
 596         mm_init();
 597
 598         ftrace_init();
 599
 600         /* trace_printk can be enabled here */
 601         early_trace_init();
 602
 603         /*
 604          * Set up the scheduler prior starting any interrupts (such as the
 605          * timer interrupt). Full topology setup happens at smp_init()
 606          * time - but meanwhile we still have a functioning scheduler.
 607          */
 608         sched_init();
 609         /*
 610          * Disable preemption - early bootup scheduling is extremely
 611          * fragile until we cpu_idle() for the first time.
 612          */
 613         preempt_disable();
 614         if (WARN(!irqs_disabled(),
 615                  "Interrupts were enabled *very* early, fixing it\n"))
 616                 local_irq_disable();
 617         radix_tree_init();
 618
 619         /*
 620          * Set up housekeeping before setting up workqueues to allow the unbound
 621          * workqueue to take non-housekeeping into account.
 622          */
 623         housekeeping_init();
 624
 625         /*
 626          * Allow workqueue creation and work item queueing/cancelling
 627          * early.  Work item execution depends on kthreads and starts after
 628          * workqueue_init().
 629          */
 630         workqueue_init_early();
 631
 632         rcu_init();
 633
 634         /* Trace events are available after this */
 635         trace_init();
 636
 637         if (initcall_debug)
 638                 initcall_debug_enable();
 639
 640         context_tracking_init();
 641         /* init some links before init_ISA_irqs() */
 642         early_irq_init();
 643         init_IRQ();
 644         tick_init();
 645         rcu_init_nohz();
 646         init_timers();
 647         hrtimers_init();
 648         softirq_init();
 649         timekeeping_init();
 650         time_init();
 651         printk_safe_init();
 652         perf_event_init();
 653         profile_init();
 654         call_function_init();
 655         WARN(!irqs_disabled(), "Interrupts were enabled early\n");
 656
 657         early_boot_irqs_disabled = false;
 658         local_irq_enable();
 659
 660         kmem_cache_init_late();
 661
 662         /*
 663          * HACK ALERT! This is early. We're enabling the console before
 664          * we've done PCI setups etc, and console_init() must be aware of
 665          * this. But we do want output early, in case something goes wrong.
 666          */
 667         console_init();
 668         if (panic_later)
 669                 panic("Too many boot %s vars at `%s'", panic_later,
 670                       panic_param);
 671
 672         lockdep_init();
 673
 674         /*
 675          * Need to run this when irqs are enabled, because it wants
 676          * to self-test [hard/soft]-irqs on/off lock inversion bugs
 677          * too:
 678          */
 679         locking_selftest();
 680
 681         /*
 682          * This needs to be called before any devices perform DMA
 683          * operations that might use the SWIOTLB bounce buffers. It will
 684          * mark the bounce buffers as decrypted so that their usage will
 685          * not cause "plain-text" data to be decrypted when accessed.
 686          */
 687         mem_encrypt_init();
 688
 689 #ifdef CONFIG_BLK_DEV_INITRD
 690         if (initrd_start && !initrd_below_start_ok &&
 691             page_to_pfn(virt_to_page((void *)initrd_start)) < min_low_pfn) {
 692                 pr_crit("initrd overwritten (0x%08lx < 0x%08lx) - disabling it.\n",
 693                     page_to_pfn(virt_to_page((void *)initrd_start)),
 694                     min_low_pfn);
 695                 initrd_start = 0;
 696         }
 697 #endif
 698         page_ext_init();
 699         kmemleak_init();
 700         setup_per_cpu_pageset();
 701         numa_policy_init();
 702         acpi_early_init();
 703         if (late_time_init)
 704                 late_time_init();
 705         sched_clock_init();
 706         calibrate_delay();
 707         pid_idr_init();
 708         anon_vma_init();
 709 #ifdef CONFIG_X86
 710         if (efi_enabled(EFI_RUNTIME_SERVICES))
 711                 efi_enter_virtual_mode();
 712 #endif
 713         thread_stack_cache_init();
 714         cred_init();
 715         fork_init();
 716         proc_caches_init();
 717         uts_ns_init();
 718         buffer_init();
 719         key_init();
 720         security_init();
 721         dbg_late_init();
 722         vfs_caches_init();
 723         pagecache_init();
 724         signals_init();
 725         seq_file_init();
 726         proc_root_init();
 727         nsfs_init();
 728         cpuset_init();
 729         cgroup_init();
 730         taskstats_init_early();
 731         delayacct_init();
 732
 733         check_bugs();
 734
 735         acpi_subsystem_init();
 736         arch_post_acpi_subsys_init();
 737         sfi_init_late();
 738
 739         /* Do the rest non-__init'ed, we're now alive */
 740         arch_call_rest_init();
 741 }
 742
 743 /* Call all constructor functions linked into the kernel. */
 744 static void __init do_ctors(void)
 745 {
 746 #ifdef CONFIG_CONSTRUCTORS
 747         ctor_fn_t *fn = (ctor_fn_t *) __ctors_start;
 748
 749         for (; fn < (ctor_fn_t *) __ctors_end; fn++)
 750                 (*fn)();
 751 #endif
 752 }
 753
 754 #ifdef CONFIG_KALLSYMS
 755 struct blacklist_entry {
 756         struct list_head next;
 757         char *buf;
 758 };
 759
 760 static __initdata_or_module LIST_HEAD(blacklisted_initcalls);
 761
 762 static int __init initcall_blacklist(char *str)
 763 {
 764         char *str_entry;
 765         struct blacklist_entry *entry;
 766
 767         /* str argument is a comma-separated list of functions */
 768         do {
 769                 str_entry = strsep(&str, ",");
 770                 if (str_entry) {
 771                         pr_debug("blacklisting initcall %s\n", str_entry);
 772                         entry = memblock_alloc(sizeof(*entry),
 773                                                SMP_CACHE_BYTES);
 774                         entry->buf = memblock_alloc(strlen(str_entry) + 1,
 775                                                     SMP_CACHE_BYTES);
 776                         strcpy(entry->buf, str_entry);
 777                         list_add(&entry->next, &blacklisted_initcalls);
 778                 }
 779         } while (str_entry);
 780
 781         return 0;
 782 }
 783
 784 static bool __init_or_module initcall_blacklisted(initcall_t fn)
 785 {
 786         struct blacklist_entry *entry;
 787         char fn_name[KSYM_SYMBOL_LEN];
 788         unsigned long addr;
 789
 790         if (list_empty(&blacklisted_initcalls))
 791                 return false;
 792
 793         addr = (unsigned long) dereference_function_descriptor(fn);
 794         sprint_symbol_no_offset(fn_name, addr);
 795
 796         /*
 797          * fn will be "function_name [module_name]" where [module_name] is not
 798          * displayed for built-in init functions.  Strip off the [module_name].
 799          */
 800         strreplace(fn_name, ' ', '\0');
 801
 802         list_for_each_entry(entry, &blacklisted_initcalls, next) {
 803                 if (!strcmp(fn_name, entry->buf)) {
 804                         pr_debug("initcall %s blacklisted\n", fn_name);
 805                         return true;
 806                 }
 807         }
 808
 809         return false;
 810 }
 811 #else
 812 static int __init initcall_blacklist(char *str)
 813 {
 814         pr_warn("initcall_blacklist requires CONFIG_KALLSYMS\n");
 815         return 0;
 816 }
 817
 818 static bool __init_or_module initcall_blacklisted(initcall_t fn)
 819 {
 820         return false;
 821 }
 822 #endif
 823 __setup("initcall_blacklist=", initcall_blacklist);
 824
 825 static __init_or_module void
 826 trace_initcall_start_cb(void *data, initcall_t fn)
 827 {
 828         ktime_t *calltime = (ktime_t *)data;
 829
 830         printk(KERN_DEBUG "calling  %pF @ %i\n", fn, task_pid_nr(current));
 831         *calltime = ktime_get();
 832 }
 833
 834 static __init_or_module void
 835 trace_initcall_finish_cb(void *data, initcall_t fn, int ret)
 836 {
 837         ktime_t *calltime = (ktime_t *)data;
 838         ktime_t delta, rettime;
 839         unsigned long long duration;
 840
 841         rettime = ktime_get();
 842         delta = ktime_sub(rettime, *calltime);
 843         duration = (unsigned long long) ktime_to_ns(delta) >> 10;
 844         printk(KERN_DEBUG "initcall %pF returned %d after %lld usecs\n",
 845                  fn, ret, duration);
 846 }
 847
 848 static ktime_t initcall_calltime;
 849
 850 #ifdef TRACEPOINTS_ENABLED
 851 static void __init initcall_debug_enable(void)
 852 {
 853         int ret;
 854
 855         ret = register_trace_initcall_start(trace_initcall_start_cb,
 856                                             &initcall_calltime);
 857         ret |= register_trace_initcall_finish(trace_initcall_finish_cb,
 858                                               &initcall_calltime);
 859         WARN(ret, "Failed to register initcall tracepoints\n");
 860 }
 861 # define do_trace_initcall_start        trace_initcall_start
 862 # define do_trace_initcall_finish       trace_initcall_finish
 863 #else
 864 static inline void do_trace_initcall_start(initcall_t fn)
 865 {
 866         if (!initcall_debug)
 867                 return;
 868         trace_initcall_start_cb(&initcall_calltime, fn);
 869 }
 870 static inline void do_trace_initcall_finish(initcall_t fn, int ret)
 871 {
 872         if (!initcall_debug)
 873                 return;
 874         trace_initcall_finish_cb(&initcall_calltime, fn, ret);
 875 }
 876 #endif /* !TRACEPOINTS_ENABLED */
 877
 878 int __init_or_module do_one_initcall(initcall_t fn)
 879 {
 880         int count = preempt_count();
 881         char msgbuf[64];
 882         int ret;
 883
 884         if (initcall_blacklisted(fn))
 885                 return -EPERM;
 886
 887         do_trace_initcall_start(fn);
 888         ret = fn();
 889         do_trace_initcall_finish(fn, ret);
 890
 891         msgbuf[0] = 0;
 892
 893         if (preempt_count() != count) {
 894                 sprintf(msgbuf, "preemption imbalance ");
 895                 preempt_count_set(count);
 896         }
 897         if (irqs_disabled()) {
 898                 strlcat(msgbuf, "disabled interrupts ", sizeof(msgbuf));
 899                 local_irq_enable();
 900         }
 901         WARN(msgbuf[0], "initcall %pF returned with %s\n", fn, msgbuf);
 902
 903         add_latent_entropy();
 904         return ret;
 905 }
 906
 907
 908 extern initcall_entry_t __initcall_start[];
 909 extern initcall_entry_t __initcall0_start[];
 910 extern initcall_entry_t __initcall1_start[];
 911 extern initcall_entry_t __initcall2_start[];
 912 extern initcall_entry_t __initcall3_start[];
 913 extern initcall_entry_t __initcall4_start[];
 914 extern initcall_entry_t __initcall5_start[];
 915 extern initcall_entry_t __initcall6_start[];
 916 extern initcall_entry_t __initcall7_start[];
 917 extern initcall_entry_t __initcall_end[];
 918
 919 static initcall_entry_t *initcall_levels[] __initdata = {
 920         __initcall0_start,
 921         __initcall1_start,
 922         __initcall2_start,
 923         __initcall3_start,
 924         __initcall4_start,
 925         __initcall5_start,
 926         __initcall6_start,
 927         __initcall7_start,
 928         __initcall_end,
 929 };
 930
 931 /* Keep these in sync with initcalls in include/linux/init.h */
 932 static const char *initcall_level_names[] __initdata = {
 933         "pure",
 934         "core",
 935         "postcore",
 936         "arch",
 937         "subsys",
 938         "fs",
 939         "device",
 940         "late",
 941 };
 942
 943 static void __init do_initcall_level(int level)
 944 {
 945         initcall_entry_t *fn;
 946
 947         strcpy(initcall_command_line, saved_command_line);
 948         parse_args(initcall_level_names[level],
 949                    initcall_command_line, __start___param,
 950                    __stop___param - __start___param,
 951                    level, level,
 952                    NULL, &repair_env_string);
 953
 954         trace_initcall_level(initcall_level_names[level]);
 955         for (fn = initcall_levels[level]; fn < initcall_levels[level+1]; fn++)
 956                 do_one_initcall(initcall_from_entry(fn));
 957 }
 958
 959 static void __init do_initcalls(void)
 960 {
 961         int level;
 962
 963         for (level = 0; level < ARRAY_SIZE(initcall_levels) - 1; level++)
 964                 do_initcall_level(level);
 965 }
 966
 967 /*
 968  * Ok, the machine is now initialized. None of the devices
 969  * have been touched yet, but the CPU subsystem is up and
 970  * running, and memory and process management works.
 971  *
 972  * Now we can finally start doing some real work..
 973  */
 974 static void __init do_basic_setup(void)
 975 {
 976         cpuset_init_smp();
 977         shmem_init();
 978         driver_init();
 979         init_irq_proc();
 980         do_ctors();
 981         usermodehelper_enable();
 982         do_initcalls();
 983 }
 984
 985 static void __init do_pre_smp_initcalls(void)
 986 {
 987         initcall_entry_t *fn;
 988
 989         trace_initcall_level("early");
 990         for (fn = __initcall_start; fn < __initcall0_start; fn++)
 991                 do_one_initcall(initcall_from_entry(fn));
 992 }
 993
 994 static int run_init_process(const char *init_filename)
 995 {
 996         argv_init[0] = init_filename;
 997         pr_info("Run %s as init process\n", init_filename);
 998         return do_execve(getname_kernel(init_filename),
 999                 (const char __user *const __user *)argv_init,
1000                 (const char __user *const __user *)envp_init);
1001 }
1002
1003 static int try_to_run_init_process(const char *init_filename)
1004 {
1005         int ret;
1006
1007         ret = run_init_process(init_filename);
1008
1009         if (ret && ret != -ENOENT) {
1010                 pr_err("Starting init: %s exists but couldn't execute it (error %d)\n",
1011                        init_filename, ret);
1012         }
1013
1014         return ret;
1015 }
1016
1017 static noinline void __init kernel_init_freeable(void);
1018
1019 #if defined(CONFIG_STRICT_KERNEL_RWX) || defined(CONFIG_STRICT_MODULE_RWX)
1020 bool rodata_enabled __ro_after_init = true;
1021 static int __init set_debug_rodata(char *str)
1022 {
1023         return strtobool(str, &rodata_enabled);
1024 }
1025 __setup("rodata=", set_debug_rodata);
1026 #endif
1027
1028 #ifdef CONFIG_STRICT_KERNEL_RWX
1029 static void mark_readonly(void)
1030 {
1031         if (rodata_enabled) {
1032                 /*
1033                  * load_module() results in W+X mappings, which are cleaned
1034                  * up with call_rcu().  Let's make sure that queued work is
1035                  * flushed so that we don't hit false positives looking for
1036                  * insecure pages which are W+X.
1037                  */
1038                 rcu_barrier();
1039                 mark_rodata_ro();
1040                 rodata_test();
1041         } else
1042                 pr_info("Kernel memory protection disabled.\n");
1043 }
1044 #else
1045 static inline void mark_readonly(void)
1046 {
1047         pr_warn("This architecture does not have kernel memory protection.\n");
1048 }
1049 #endif
1050
1051 static int __ref kernel_init(void *unused)
1052 {
1053         int ret;
1054
1055         kernel_init_freeable();
1056         /* need to finish all async __init code before freeing the memory */
1057         async_synchronize_full();
1058         ftrace_free_init_mem();
1059         free_initmem();
1060         mark_readonly();
1061
1062         /*
1063          * Kernel mappings are now finalized - update the userspace page-table
1064          * to finalize PTI.
1065          */
1066         pti_finalize();
1067
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 }