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/interrupt.h>
  50 #include <linux/taskstats_kern.h>
  51 #include <linux/delayacct.h>
  52 #include <linux/unistd.h>
  53 #include <linux/rmap.h>
  54 #include <linux/mempolicy.h>
  55 #include <linux/key.h>
  56 #include <linux/buffer_head.h>
  57 #include <linux/page_ext.h>
  58 #include <linux/debug_locks.h>
  59 #include <linux/debugobjects.h>
  60 #include <linux/lockdep.h>
  61 #include <linux/kmemleak.h>
  62 #include <linux/pid_namespace.h>
  63 #include <linux/device.h>
  64 #include <linux/kthread.h>
  65 #include <linux/sched.h>
  66 #include <linux/sched/init.h>
  67 #include <linux/signal.h>
  68 #include <linux/idr.h>
  69 #include <linux/kgdb.h>
  70 #include <linux/ftrace.h>
  71 #include <linux/async.h>
  72 #include <linux/kmemcheck.h>
  73 #include <linux/sfi.h>
  74 #include <linux/shmem_fs.h>
  75 #include <linux/slab.h>
  76 #include <linux/perf_event.h>
  77 #include <linux/ptrace.h>
  78 #include <linux/blkdev.h>
  79 #include <linux/elevator.h>
  80 #include <linux/sched_clock.h>
  81 #include <linux/sched/task.h>
  82 #include <linux/sched/task_stack.h>
  83 #include <linux/context_tracking.h>
  84 #include <linux/random.h>
  85 #include <linux/list.h>
  86 #include <linux/integrity.h>
  87 #include <linux/proc_ns.h>
  88 #include <linux/io.h>
  89 #include <linux/cache.h>
  90 #include <linux/rodata_test.h>
  91
  92 #include <asm/io.h>
  93 #include <asm/bugs.h>
  94 #include <asm/setup.h>
  95 #include <asm/sections.h>
  96 #include <asm/cacheflush.h>
  97
  98 static int kernel_init(void *);
  99
 100 extern void init_IRQ(void);
 101 extern void fork_init(void);
 102 extern void radix_tree_init(void);
 103
 104 /*
 105  * Debug helper: via this flag we know that we are in 'early bootup code'
 106  * where only the boot processor is running with IRQ disabled.  This means
 107  * two things - IRQ must not be enabled before the flag is cleared and some
 108  * operations which are not allowed with IRQ disabled are allowed while the
 109  * flag is set.
 110  */
 111 bool early_boot_irqs_disabled __read_mostly;
 112
 113 enum system_states system_state __read_mostly;
 114 EXPORT_SYMBOL(system_state);
 115
 116 /*
 117  * Boot command-line arguments
 118  */
 119 #define MAX_INIT_ARGS CONFIG_INIT_ENV_ARG_LIMIT
 120 #define MAX_INIT_ENVS CONFIG_INIT_ENV_ARG_LIMIT
 121
 122 extern void time_init(void);
 123 /* Default late time init is NULL. archs can override this later. */
 124 void (*__initdata late_time_init)(void);
 125
 126 /* Untouched command line saved by arch-specific code. */
 127 char __initdata boot_command_line[COMMAND_LINE_SIZE];
 128 /* Untouched saved command line (eg. for /proc) */
 129 char *saved_command_line;
 130 /* Command line for parameter parsing */
 131 static char *static_command_line;
 132 /* Command line for per-initcall parameter parsing */
 133 static char *initcall_command_line;
 134
 135 static char *execute_command;
 136 static char *ramdisk_execute_command;
 137
 138 /*
 139  * Used to generate warnings if static_key manipulation functions are used
 140  * before jump_label_init is called.
 141  */
 142 bool static_key_initialized __read_mostly;
 143 EXPORT_SYMBOL_GPL(static_key_initialized);
 144
 145 /*
 146  * If set, this is an indication to the drivers that reset the underlying
 147  * device before going ahead with the initialization otherwise driver might
 148  * rely on the BIOS and skip the reset operation.
 149  *
 150  * This is useful if kernel is booting in an unreliable environment.
 151  * For ex. kdump situation where previous kernel has crashed, BIOS has been
 152  * skipped and devices will be in unknown state.
 153  */
 154 unsigned int reset_devices;
 155 EXPORT_SYMBOL(reset_devices);
 156
 157 static int __init set_reset_devices(char *str)
 158 {
 159         reset_devices = 1;
 160         return 1;
 161 }
 162
 163 __setup("reset_devices", set_reset_devices);
 164
 165 static const char *argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
 166 const char *envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, };
 167 static const char *panic_later, *panic_param;
 168
 169 extern const struct obs_kernel_param __setup_start[], __setup_end[];
 170
 171 static bool __init obsolete_checksetup(char *line)
 172 {
 173         const struct obs_kernel_param *p;
 174         bool had_early_param = false;
 175
 176         p = __setup_start;
 177         do {
 178                 int n = strlen(p->str);
 179                 if (parameqn(line, p->str, n)) {
 180                         if (p->early) {
 181                                 /* Already done in parse_early_param?
 182                                  * (Needs exact match on param part).
 183                                  * Keep iterating, as we can have early
 184                                  * params and __setups of same names 8( */
 185                                 if (line[n] == '\0' || line[n] == '=')
 186                                         had_early_param = true;
 187                         } else if (!p->setup_func) {
 188                                 pr_warn("Parameter %s is obsolete, ignored\n",
 189                                         p->str);
 190                                 return true;
 191                         } else if (p->setup_func(line + n))
 192                                 return true;
 193                 }
 194                 p++;
 195         } while (p < __setup_end);
 196
 197         return had_early_param;
 198 }
 199
 200 /*
 201  * This should be approx 2 Bo*oMips to start (note initial shift), and will
 202  * still work even if initially too large, it will just take slightly longer
 203  */
 204 unsigned long loops_per_jiffy = (1<<12);
 205 EXPORT_SYMBOL(loops_per_jiffy);
 206
 207 static int __init debug_kernel(char *str)
 208 {
 209         console_loglevel = CONSOLE_LOGLEVEL_DEBUG;
 210         return 0;
 211 }
 212
 213 static int __init quiet_kernel(char *str)
 214 {
 215         console_loglevel = CONSOLE_LOGLEVEL_QUIET;
 216         return 0;
 217 }
 218
 219 early_param("debug", debug_kernel);
 220 early_param("quiet", quiet_kernel);
 221
 222 static int __init loglevel(char *str)
 223 {
 224         int newlevel;
 225
 226         /*
 227          * Only update loglevel value when a correct setting was passed,
 228          * to prevent blind crashes (when loglevel being set to 0) that
 229          * are quite hard to debug
 230          */
 231         if (get_option(&str, &newlevel)) {
 232                 console_loglevel = newlevel;
 233                 return 0;
 234         }
 235
 236         return -EINVAL;
 237 }
 238
 239 early_param("loglevel", loglevel);
 240
 241 /* Change NUL term back to "=", to make "param" the whole string. */
 242 static int __init repair_env_string(char *param, char *val,
 243                                     const char *unused, void *arg)
 244 {
 245         if (val) {
 246                 /* param=val or param="val"? */
 247                 if (val == param+strlen(param)+1)
 248                         val[-1] = '=';
 249                 else if (val == param+strlen(param)+2) {
 250                         val[-2] = '=';
 251                         memmove(val-1, val, strlen(val)+1);
 252                         val--;
 253                 } else
 254                         BUG();
 255         }
 256         return 0;
 257 }
 258
 259 /* Anything after -- gets handed straight to init. */
 260 static int __init set_init_arg(char *param, char *val,
 261                                const char *unused, void *arg)
 262 {
 263         unsigned int i;
 264
 265         if (panic_later)
 266                 return 0;
 267
 268         repair_env_string(param, val, unused, NULL);
 269
 270         for (i = 0; argv_init[i]; i++) {
 271                 if (i == MAX_INIT_ARGS) {
 272                         panic_later = "init";
 273                         panic_param = param;
 274                         return 0;
 275                 }
 276         }
 277         argv_init[i] = param;
 278         return 0;
 279 }
 280
 281 /*
 282  * Unknown boot options get handed to init, unless they look like
 283  * unused parameters (modprobe will find them in /proc/cmdline).
 284  */
 285 static int __init unknown_bootoption(char *param, char *val,
 286                                      const char *unused, void *arg)
 287 {
 288         repair_env_string(param, val, unused, NULL);
 289
 290         /* Handle obsolete-style parameters */
 291         if (obsolete_checksetup(param))
 292                 return 0;
 293
 294         /* Unused module parameter. */
 295         if (strchr(param, '.') && (!val || strchr(param, '.') < val))
 296                 return 0;
 297
 298         if (panic_later)
 299                 return 0;
 300
 301         if (val) {
 302                 /* Environment option */
 303                 unsigned int i;
 304                 for (i = 0; envp_init[i]; i++) {
 305                         if (i == MAX_INIT_ENVS) {
 306                                 panic_later = "env";
 307                                 panic_param = param;
 308                         }
 309                         if (!strncmp(param, envp_init[i], val - param))
 310                                 break;
 311                 }
 312                 envp_init[i] = param;
 313         } else {
 314                 /* Command line option */
 315                 unsigned int i;
 316                 for (i = 0; argv_init[i]; i++) {
 317                         if (i == MAX_INIT_ARGS) {
 318                                 panic_later = "init";
 319                                 panic_param = param;
 320                         }
 321                 }
 322                 argv_init[i] = param;
 323         }
 324         return 0;
 325 }
 326
 327 static int __init init_setup(char *str)
 328 {
 329         unsigned int i;
 330
 331         execute_command = str;
 332         /*
 333          * In case LILO is going to boot us with default command line,
 334          * it prepends "auto" before the whole cmdline which makes
 335          * the shell think it should execute a script with such name.
 336          * So we ignore all arguments entered _before_ init=... [MJ]
 337          */
 338         for (i = 1; i < MAX_INIT_ARGS; i++)
 339                 argv_init[i] = NULL;
 340         return 1;
 341 }
 342 __setup("init=", init_setup);
 343
 344 static int __init rdinit_setup(char *str)
 345 {
 346         unsigned int i;
 347
 348         ramdisk_execute_command = str;
 349         /* See "auto" comment in init_setup */
 350         for (i = 1; i < MAX_INIT_ARGS; i++)
 351                 argv_init[i] = NULL;
 352         return 1;
 353 }
 354 __setup("rdinit=", rdinit_setup);
 355
 356 #ifndef CONFIG_SMP
 357 static const unsigned int setup_max_cpus = NR_CPUS;
 358 static inline void setup_nr_cpu_ids(void) { }
 359 static inline void smp_prepare_cpus(unsigned int maxcpus) { }
 360 #endif
 361
 362 /*
 363  * We need to store the untouched command line for future reference.
 364  * We also need to store the touched command line since the parameter
 365  * parsing is performed in place, and we should allow a component to
 366  * store reference of name/value for future reference.
 367  */
 368 static void __init setup_command_line(char *command_line)
 369 {
 370         saved_command_line =
 371                 memblock_virt_alloc(strlen(boot_command_line) + 1, 0);
 372         initcall_command_line =
 373                 memblock_virt_alloc(strlen(boot_command_line) + 1, 0);
 374         static_command_line = memblock_virt_alloc(strlen(command_line) + 1, 0);
 375         strcpy(saved_command_line, boot_command_line);
 376         strcpy(static_command_line, command_line);
 377 }
 378
 379 /*
 380  * We need to finalize in a non-__init function or else race conditions
 381  * between the root thread and the init thread may cause start_kernel to
 382  * be reaped by free_initmem before the root thread has proceeded to
 383  * cpu_idle.
 384  *
 385  * gcc-3.4 accidentally inlines this function, so use noinline.
 386  */
 387
 388 static __initdata DECLARE_COMPLETION(kthreadd_done);
 389
 390 static noinline void __ref rest_init(void)
 391 {
 392         int pid;
 393
 394         rcu_scheduler_starting();
 395         /*
 396          * We need to spawn init first so that it obtains pid 1, however
 397          * the init task will end up wanting to create kthreads, which, if
 398          * we schedule it before we create kthreadd, will OOPS.
 399          */
 400         kernel_thread(kernel_init, NULL, CLONE_FS);
 401         numa_default_policy();
 402         pid = kernel_thread(kthreadd, NULL, CLONE_FS | CLONE_FILES);
 403         rcu_read_lock();
 404         kthreadd_task = find_task_by_pid_ns(pid, &init_pid_ns);
 405         rcu_read_unlock();
 406         complete(&kthreadd_done);
 407
 408         /*
 409          * The boot idle thread must execute schedule()
 410          * at least once to get things moving:
 411          */
 412         init_idle_bootup_task(current);
 413         schedule_preempt_disabled();
 414         /* Call into cpu_idle with preempt disabled */
 415         cpu_startup_entry(CPUHP_ONLINE);
 416 }
 417
 418 /* Check for early params. */
 419 static int __init do_early_param(char *param, char *val,
 420                                  const char *unused, void *arg)
 421 {
 422         const struct obs_kernel_param *p;
 423
 424         for (p = __setup_start; p < __setup_end; p++) {
 425                 if ((p->early && parameq(param, p->str)) ||
 426                     (strcmp(param, "console") == 0 &&
 427                      strcmp(p->str, "earlycon") == 0)
 428                 ) {
 429                         if (p->setup_func(val) != 0)
 430                                 pr_warn("Malformed early option '%s'\n", param);
 431                 }
 432         }
 433         /* We accept everything at this stage. */
 434         return 0;
 435 }
 436
 437 void __init parse_early_options(char *cmdline)
 438 {
 439         parse_args("early options", cmdline, NULL, 0, 0, 0, NULL,
 440                    do_early_param);
 441 }
 442
 443 /* Arch code calls this early on, or if not, just before other parsing. */
 444 void __init parse_early_param(void)
 445 {
 446         static int done __initdata;
 447         static char tmp_cmdline[COMMAND_LINE_SIZE] __initdata;
 448
 449         if (done)
 450                 return;
 451
 452         /* All fall through to do_early_param. */
 453         strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);
 454         parse_early_options(tmp_cmdline);
 455         done = 1;
 456 }
 457
 458 void __init __weak arch_post_acpi_subsys_init(void) { }
 459
 460 void __init __weak smp_setup_processor_id(void)
 461 {
 462 }
 463
 464 # if THREAD_SIZE >= PAGE_SIZE
 465 void __init __weak thread_stack_cache_init(void)
 466 {
 467 }
 468 #endif
 469
 470 /*
 471  * Set up kernel memory allocators
 472  */
 473 static void __init mm_init(void)
 474 {
 475         /*
 476          * page_ext requires contiguous pages,
 477          * bigger than MAX_ORDER unless SPARSEMEM.
 478          */
 479         page_ext_init_flatmem();
 480         mem_init();
 481         kmem_cache_init();
 482         percpu_init_late();
 483         pgtable_init();
 484         vmalloc_init();
 485         ioremap_huge_init();
 486 }
 487
 488 asmlinkage __visible void __init start_kernel(void)
 489 {
 490         char *command_line;
 491         char *after_dashes;
 492
 493         set_task_stack_end_magic(&init_task);
 494         smp_setup_processor_id();
 495         debug_objects_early_init();
 496
 497         /*
 498          * Set up the initial canary ASAP:
 499          */
 500         boot_init_stack_canary();
 501
 502         cgroup_init_early();
 503
 504         local_irq_disable();
 505         early_boot_irqs_disabled = true;
 506
 507         /*
 508          * Interrupts are still disabled. Do necessary setups, then
 509          * enable them.
 510          */
 511         boot_cpu_init();
 512         page_address_init();
 513         pr_notice("%s", linux_banner);
 514         setup_arch(&command_line);
 515         mm_init_cpumask(&init_mm);
 516         setup_command_line(command_line);
 517         setup_nr_cpu_ids();
 518         setup_per_cpu_areas();
 519         boot_cpu_state_init();
 520         smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */
 521
 522         build_all_zonelists(NULL, NULL);
 523         page_alloc_init();
 524
 525         pr_notice("Kernel command line: %s\n", boot_command_line);
 526         parse_early_param();
 527         after_dashes = parse_args("Booting kernel",
 528                                   static_command_line, __start___param,
 529                                   __stop___param - __start___param,
 530                                   -1, -1, NULL, &unknown_bootoption);
 531         if (!IS_ERR_OR_NULL(after_dashes))
 532                 parse_args("Setting init args", after_dashes, NULL, 0, -1, -1,
 533                            NULL, set_init_arg);
 534
 535         jump_label_init();
 536
 537         /*
 538          * These use large bootmem allocations and must precede
 539          * kmem_cache_init()
 540          */
 541         setup_log_buf(0);
 542         pidhash_init();
 543         vfs_caches_init_early();
 544         sort_main_extable();
 545         trap_init();
 546         mm_init();
 547
 548         ftrace_init();
 549
 550         /* trace_printk can be enabled here */
 551         early_trace_init();
 552
 553         /*
 554          * Set up the scheduler prior starting any interrupts (such as the
 555          * timer interrupt). Full topology setup happens at smp_init()
 556          * time - but meanwhile we still have a functioning scheduler.
 557          */
 558         sched_init();
 559         /*
 560          * Disable preemption - early bootup scheduling is extremely
 561          * fragile until we cpu_idle() for the first time.
 562          */
 563         preempt_disable();
 564         if (WARN(!irqs_disabled(),
 565                  "Interrupts were enabled *very* early, fixing it\n"))
 566                 local_irq_disable();
 567         radix_tree_init();
 568
 569         /*
 570          * Allow workqueue creation and work item queueing/cancelling
 571          * early.  Work item execution depends on kthreads and starts after
 572          * workqueue_init().
 573          */
 574         workqueue_init_early();
 575
 576         rcu_init();
 577
 578         /* Trace events are available after this */
 579         trace_init();
 580
 581         context_tracking_init();
 582         /* init some links before init_ISA_irqs() */
 583         early_irq_init();
 584         init_IRQ();
 585         tick_init();
 586         rcu_init_nohz();
 587         init_timers();
 588         hrtimers_init();
 589         softirq_init();
 590         timekeeping_init();
 591         time_init();
 592         sched_clock_postinit();
 593         printk_safe_init();
 594         perf_event_init();
 595         profile_init();
 596         call_function_init();
 597         WARN(!irqs_disabled(), "Interrupts were enabled early\n");
 598         early_boot_irqs_disabled = false;
 599         local_irq_enable();
 600
 601         kmem_cache_init_late();
 602
 603         /*
 604          * HACK ALERT! This is early. We're enabling the console before
 605          * we've done PCI setups etc, and console_init() must be aware of
 606          * this. But we do want output early, in case something goes wrong.
 607          */
 608         console_init();
 609         if (panic_later)
 610                 panic("Too many boot %s vars at `%s'", panic_later,
 611                       panic_param);
 612
 613         lockdep_info();
 614
 615         /*
 616          * Need to run this when irqs are enabled, because it wants
 617          * to self-test [hard/soft]-irqs on/off lock inversion bugs
 618          * too:
 619          */
 620         locking_selftest();
 621
 622 #ifdef CONFIG_BLK_DEV_INITRD
 623         if (initrd_start && !initrd_below_start_ok &&
 624             page_to_pfn(virt_to_page((void *)initrd_start)) < min_low_pfn) {
 625                 pr_crit("initrd overwritten (0x%08lx < 0x%08lx) - disabling it.\n",
 626                     page_to_pfn(virt_to_page((void *)initrd_start)),
 627                     min_low_pfn);
 628                 initrd_start = 0;
 629         }
 630 #endif
 631         page_ext_init();
 632         debug_objects_mem_init();
 633         kmemleak_init();
 634         setup_per_cpu_pageset();
 635         numa_policy_init();
 636         if (late_time_init)
 637                 late_time_init();
 638         calibrate_delay();
 639         pidmap_init();
 640         anon_vma_init();
 641         acpi_early_init();
 642 #ifdef CONFIG_X86
 643         if (efi_enabled(EFI_RUNTIME_SERVICES))
 644                 efi_enter_virtual_mode();
 645 #endif
 646 #ifdef CONFIG_X86_ESPFIX64
 647         /* Should be run before the first non-init thread is created */
 648         init_espfix_bsp();
 649 #endif
 650         thread_stack_cache_init();
 651         cred_init();
 652         fork_init();
 653         proc_caches_init();
 654         buffer_init();
 655         key_init();
 656         security_init();
 657         dbg_late_init();
 658         vfs_caches_init();
 659         pagecache_init();
 660         signals_init();
 661         proc_root_init();
 662         nsfs_init();
 663         cpuset_init();
 664         cgroup_init();
 665         taskstats_init_early();
 666         delayacct_init();
 667
 668         check_bugs();
 669
 670         acpi_subsystem_init();
 671         arch_post_acpi_subsys_init();
 672         sfi_init_late();
 673
 674         if (efi_enabled(EFI_RUNTIME_SERVICES)) {
 675                 efi_free_boot_services();
 676         }
 677
 678         /* Do the rest non-__init'ed, we're now alive */
 679         rest_init();
 680 }
 681
 682 /* Call all constructor functions linked into the kernel. */
 683 static void __init do_ctors(void)
 684 {
 685 #ifdef CONFIG_CONSTRUCTORS
 686         ctor_fn_t *fn = (ctor_fn_t *) __ctors_start;
 687
 688         for (; fn < (ctor_fn_t *) __ctors_end; fn++)
 689                 (*fn)();
 690 #endif
 691 }
 692
 693 bool initcall_debug;
 694 core_param(initcall_debug, initcall_debug, bool, 0644);
 695
 696 #ifdef CONFIG_KALLSYMS
 697 struct blacklist_entry {
 698         struct list_head next;
 699         char *buf;
 700 };
 701
 702 static __initdata_or_module LIST_HEAD(blacklisted_initcalls);
 703
 704 static int __init initcall_blacklist(char *str)
 705 {
 706         char *str_entry;
 707         struct blacklist_entry *entry;
 708
 709         /* str argument is a comma-separated list of functions */
 710         do {
 711                 str_entry = strsep(&str, ",");
 712                 if (str_entry) {
 713                         pr_debug("blacklisting initcall %s\n", str_entry);
 714                         entry = alloc_bootmem(sizeof(*entry));
 715                         entry->buf = alloc_bootmem(strlen(str_entry) + 1);
 716                         strcpy(entry->buf, str_entry);
 717                         list_add(&entry->next, &blacklisted_initcalls);
 718                 }
 719         } while (str_entry);
 720
 721         return 0;
 722 }
 723
 724 static bool __init_or_module initcall_blacklisted(initcall_t fn)
 725 {
 726         struct blacklist_entry *entry;
 727         char fn_name[KSYM_SYMBOL_LEN];
 728         unsigned long addr;
 729
 730         if (list_empty(&blacklisted_initcalls))
 731                 return false;
 732
 733         addr = (unsigned long) dereference_function_descriptor(fn);
 734         sprint_symbol_no_offset(fn_name, addr);
 735
 736         /*
 737          * fn will be "function_name [module_name]" where [module_name] is not
 738          * displayed for built-in init functions.  Strip off the [module_name].
 739          */
 740         strreplace(fn_name, ' ', '\0');
 741
 742         list_for_each_entry(entry, &blacklisted_initcalls, next) {
 743                 if (!strcmp(fn_name, entry->buf)) {
 744                         pr_debug("initcall %s blacklisted\n", fn_name);
 745                         return true;
 746                 }
 747         }
 748
 749         return false;
 750 }
 751 #else
 752 static int __init initcall_blacklist(char *str)
 753 {
 754         pr_warn("initcall_blacklist requires CONFIG_KALLSYMS\n");
 755         return 0;
 756 }
 757
 758 static bool __init_or_module initcall_blacklisted(initcall_t fn)
 759 {
 760         return false;
 761 }
 762 #endif
 763 __setup("initcall_blacklist=", initcall_blacklist);
 764
 765 static int __init_or_module do_one_initcall_debug(initcall_t fn)
 766 {
 767         ktime_t calltime, delta, rettime;
 768         unsigned long long duration;
 769         int ret;
 770
 771         printk(KERN_DEBUG "calling  %pF @ %i\n", fn, task_pid_nr(current));
 772         calltime = ktime_get();
 773         ret = fn();
 774         rettime = ktime_get();
 775         delta = ktime_sub(rettime, calltime);
 776         duration = (unsigned long long) ktime_to_ns(delta) >> 10;
 777         printk(KERN_DEBUG "initcall %pF returned %d after %lld usecs\n",
 778                  fn, ret, duration);
 779
 780         return ret;
 781 }
 782
 783 int __init_or_module do_one_initcall(initcall_t fn)
 784 {
 785         int count = preempt_count();
 786         int ret;
 787         char msgbuf[64];
 788
 789         if (initcall_blacklisted(fn))
 790                 return -EPERM;
 791
 792         if (initcall_debug)
 793                 ret = do_one_initcall_debug(fn);
 794         else
 795                 ret = fn();
 796
 797         msgbuf[0] = 0;
 798
 799         if (preempt_count() != count) {
 800                 sprintf(msgbuf, "preemption imbalance ");
 801                 preempt_count_set(count);
 802         }
 803         if (irqs_disabled()) {
 804                 strlcat(msgbuf, "disabled interrupts ", sizeof(msgbuf));
 805                 local_irq_enable();
 806         }
 807         WARN(msgbuf[0], "initcall %pF returned with %s\n", fn, msgbuf);
 808
 809         add_latent_entropy();
 810         return ret;
 811 }
 812
 813
 814 extern initcall_t __initcall_start[];
 815 extern initcall_t __initcall0_start[];
 816 extern initcall_t __initcall1_start[];
 817 extern initcall_t __initcall2_start[];
 818 extern initcall_t __initcall3_start[];
 819 extern initcall_t __initcall4_start[];
 820 extern initcall_t __initcall5_start[];
 821 extern initcall_t __initcall6_start[];
 822 extern initcall_t __initcall7_start[];
 823 extern initcall_t __initcall_end[];
 824
 825 static initcall_t *initcall_levels[] __initdata = {
 826         __initcall0_start,
 827         __initcall1_start,
 828         __initcall2_start,
 829         __initcall3_start,
 830         __initcall4_start,
 831         __initcall5_start,
 832         __initcall6_start,
 833         __initcall7_start,
 834         __initcall_end,
 835 };
 836
 837 /* Keep these in sync with initcalls in include/linux/init.h */
 838 static char *initcall_level_names[] __initdata = {
 839         "early",
 840         "core",
 841         "postcore",
 842         "arch",
 843         "subsys",
 844         "fs",
 845         "device",
 846         "late",
 847 };
 848
 849 static void __init do_initcall_level(int level)
 850 {
 851         initcall_t *fn;
 852
 853         strcpy(initcall_command_line, saved_command_line);
 854         parse_args(initcall_level_names[level],
 855                    initcall_command_line, __start___param,
 856                    __stop___param - __start___param,
 857                    level, level,
 858                    NULL, &repair_env_string);
 859
 860         for (fn = initcall_levels[level]; fn < initcall_levels[level+1]; fn++)
 861                 do_one_initcall(*fn);
 862 }
 863
 864 static void __init do_initcalls(void)
 865 {
 866         int level;
 867
 868         for (level = 0; level < ARRAY_SIZE(initcall_levels) - 1; level++)
 869                 do_initcall_level(level);
 870 }
 871
 872 /*
 873  * Ok, the machine is now initialized. None of the devices
 874  * have been touched yet, but the CPU subsystem is up and
 875  * running, and memory and process management works.
 876  *
 877  * Now we can finally start doing some real work..
 878  */
 879 static void __init do_basic_setup(void)
 880 {
 881         cpuset_init_smp();
 882         shmem_init();
 883         driver_init();
 884         init_irq_proc();
 885         do_ctors();
 886         usermodehelper_enable();
 887         do_initcalls();
 888 }
 889
 890 static void __init do_pre_smp_initcalls(void)
 891 {
 892         initcall_t *fn;
 893
 894         for (fn = __initcall_start; fn < __initcall0_start; fn++)
 895                 do_one_initcall(*fn);
 896 }
 897
 898 /*
 899  * This function requests modules which should be loaded by default and is
 900  * called twice right after initrd is mounted and right before init is
 901  * exec'd.  If such modules are on either initrd or rootfs, they will be
 902  * loaded before control is passed to userland.
 903  */
 904 void __init load_default_modules(void)
 905 {
 906         load_default_elevator_module();
 907 }
 908
 909 static int run_init_process(const char *init_filename)
 910 {
 911         argv_init[0] = init_filename;
 912         return do_execve(getname_kernel(init_filename),
 913                 (const char __user *const __user *)argv_init,
 914                 (const char __user *const __user *)envp_init);
 915 }
 916
 917 static int try_to_run_init_process(const char *init_filename)
 918 {
 919         int ret;
 920
 921         ret = run_init_process(init_filename);
 922
 923         if (ret && ret != -ENOENT) {
 924                 pr_err("Starting init: %s exists but couldn't execute it (error %d)\n",
 925                        init_filename, ret);
 926         }
 927
 928         return ret;
 929 }
 930
 931 static noinline void __init kernel_init_freeable(void);
 932
 933 #if defined(CONFIG_STRICT_KERNEL_RWX) || defined(CONFIG_STRICT_MODULE_RWX)
 934 bool rodata_enabled __ro_after_init = true;
 935 static int __init set_debug_rodata(char *str)
 936 {
 937         return strtobool(str, &rodata_enabled);
 938 }
 939 __setup("rodata=", set_debug_rodata);
 940 #endif
 941
 942 #ifdef CONFIG_STRICT_KERNEL_RWX
 943 static void mark_readonly(void)
 944 {
 945         if (rodata_enabled) {
 946                 mark_rodata_ro();
 947                 rodata_test();
 948         } else
 949                 pr_info("Kernel memory protection disabled.\n");
 950 }
 951 #else
 952 static inline void mark_readonly(void)
 953 {
 954         pr_warn("This architecture does not have kernel memory protection.\n");
 955 }
 956 #endif
 957
 958 static int __ref kernel_init(void *unused)
 959 {
 960         int ret;
 961
 962         kernel_init_freeable();
 963         /* need to finish all async __init code before freeing the memory */
 964         async_synchronize_full();
 965         ftrace_free_init_mem();
 966         free_initmem();
 967         mark_readonly();
 968         system_state = SYSTEM_RUNNING;
 969         numa_default_policy();
 970
 971         rcu_end_inkernel_boot();
 972
 973         if (ramdisk_execute_command) {
 974                 ret = run_init_process(ramdisk_execute_command);
 975                 if (!ret)
 976                         return 0;
 977                 pr_err("Failed to execute %s (error %d)\n",
 978                        ramdisk_execute_command, ret);
 979         }
 980
 981         /*
 982          * We try each of these until one succeeds.
 983          *
 984          * The Bourne shell can be used instead of init if we are
 985          * trying to recover a really broken machine.
 986          */
 987         if (execute_command) {
 988                 ret = run_init_process(execute_command);
 989                 if (!ret)
 990                         return 0;
 991                 panic("Requested init %s failed (error %d).",
 992                       execute_command, ret);
 993         }
 994         if (!try_to_run_init_process("/sbin/init") ||
 995             !try_to_run_init_process("/etc/init") ||
 996             !try_to_run_init_process("/bin/init") ||
 997             !try_to_run_init_process("/bin/sh"))
 998                 return 0;
 999
1000         panic("No working init found.  Try passing init= option to kernel. "
1001               "See Linux Documentation/admin-guide/init.rst for guidance.");
1002 }
1003
1004 static noinline void __init kernel_init_freeable(void)
1005 {
1006         /*
1007          * Wait until kthreadd is all set-up.
1008          */
1009         wait_for_completion(&kthreadd_done);
1010
1011         /* Now the scheduler is fully set up and can do blocking allocations */
1012         gfp_allowed_mask = __GFP_BITS_MASK;
1013
1014         /*
1015          * init can allocate pages on any node
1016          */
1017         set_mems_allowed(node_states[N_MEMORY]);
1018         /*
1019          * init can run on any cpu.
1020          */
1021         set_cpus_allowed_ptr(current, cpu_all_mask);
1022
1023         cad_pid = task_pid(current);
1024
1025         smp_prepare_cpus(setup_max_cpus);
1026
1027         workqueue_init();
1028
1029         init_mm_internals();
1030
1031         do_pre_smp_initcalls();
1032         lockup_detector_init();
1033
1034         smp_init();
1035         sched_init_smp();
1036
1037         page_alloc_init_late();
1038
1039         do_basic_setup();
1040
1041         /* Open the /dev/console on the rootfs, this should never fail */
1042         if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0)
1043                 pr_err("Warning: unable to open an initial console.\n");
1044
1045         (void) sys_dup(0);
1046         (void) sys_dup(0);
1047         /*
1048          * check if there is an early userspace init.  If yes, let it do all
1049          * the work
1050          */
1051
1052         if (!ramdisk_execute_command)
1053                 ramdisk_execute_command = "/init";
1054
1055         if (sys_access((const char __user *) ramdisk_execute_command, 0) != 0) {
1056                 ramdisk_execute_command = NULL;
1057                 prepare_namespace();
1058         }
1059
1060         /*
1061          * Ok, we have completed the initial bootup, and
1062          * we're essentially up and running. Get rid of the
1063          * initmem segments and start the user-mode stuff..
1064          *
1065          * rootfs is available now, try loading the public keys
1066          * and default modules
1067          */
1068
1069         integrity_load_keys();
1070         load_default_modules();
1071 }