init/main.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *  linux/init/main.c
   4  *
   5  *  Copyright (C) 1991, 1992  Linus Torvalds
   6  *
   7  *  GK 2/5/95  -  Changed to support mounting root fs via NFS
   8  *  Added initrd & change_root: Werner Almesberger & Hans Lermen, Feb '96
   9  *  Moan early if gcc is old, avoiding bogus kernels - Paul Gortmaker, May '96
  10  *  Simplified starting of init:  Michael A. Griffith <grif@acm.org>
  11  */
  12
  13 #define DEBUG           /* Enable initcall_debug */
  14
  15 #include <linux/types.h>
  16 #include <linux/extable.h>
  17 #include <linux/module.h>
  18 #include <linux/proc_fs.h>
  19 #include <linux/binfmts.h>
  20 #include <linux/kernel.h>
  21 #include <linux/syscalls.h>
  22 #include <linux/stackprotector.h>
  23 #include <linux/string.h>
  24 #include <linux/ctype.h>
  25 #include <linux/delay.h>
  26 #include <linux/ioport.h>
  27 #include <linux/init.h>
  28 #include <linux/initrd.h>
  29 #include <linux/memblock.h>
  30 #include <linux/acpi.h>
  31 #include <linux/console.h>
  32 #include <linux/nmi.h>
  33 #include <linux/percpu.h>
  34 #include <linux/kmod.h>
  35 #include <linux/vmalloc.h>
  36 #include <linux/kernel_stat.h>
  37 #include <linux/start_kernel.h>
  38 #include <linux/security.h>
  39 #include <linux/smp.h>
  40 #include <linux/profile.h>
  41 #include <linux/rcupdate.h>
  42 #include <linux/moduleparam.h>
  43 #include <linux/kallsyms.h>
  44 #include <linux/writeback.h>
  45 #include <linux/cpu.h>
  46 #include <linux/cpuset.h>
  47 #include <linux/cgroup.h>
  48 #include <linux/efi.h>
  49 #include <linux/tick.h>
  50 #include <linux/sched/isolation.h>
  51 #include <linux/interrupt.h>
  52 #include <linux/taskstats_kern.h>
  53 #include <linux/delayacct.h>
  54 #include <linux/unistd.h>
  55 #include <linux/utsname.h>
  56 #include <linux/rmap.h>
  57 #include <linux/mempolicy.h>
  58 #include <linux/key.h>
  59 #include <linux/buffer_head.h>
  60 #include <linux/page_ext.h>
  61 #include <linux/debug_locks.h>
  62 #include <linux/debugobjects.h>
  63 #include <linux/lockdep.h>
  64 #include <linux/kmemleak.h>
  65 #include <linux/pid_namespace.h>
  66 #include <linux/device.h>
  67 #include <linux/kthread.h>
  68 #include <linux/sched.h>
  69 #include <linux/sched/init.h>
  70 #include <linux/signal.h>
  71 #include <linux/idr.h>
  72 #include <linux/kgdb.h>
  73 #include <linux/ftrace.h>
  74 #include <linux/async.h>
  75 #include <linux/sfi.h>
  76 #include <linux/shmem_fs.h>
  77 #include <linux/slab.h>
  78 #include <linux/perf_event.h>
  79 #include <linux/ptrace.h>
  80 #include <linux/pti.h>
  81 #include <linux/blkdev.h>
  82 #include <linux/elevator.h>
  83 #include <linux/sched/clock.h>
  84 #include <linux/sched/task.h>
  85 #include <linux/sched/task_stack.h>
  86 #include <linux/context_tracking.h>
  87 #include <linux/random.h>
  88 #include <linux/list.h>
  89 #include <linux/integrity.h>
  90 #include <linux/proc_ns.h>
  91 #include <linux/io.h>
  92 #include <linux/cache.h>
  93 #include <linux/rodata_test.h>
  94 #include <linux/jump_label.h>
  95 #include <linux/mem_encrypt.h>
  96
  97 #include <asm/io.h>
  98 #include <asm/bugs.h>
  99 #include <asm/setup.h>
 100 #include <asm/sections.h>
 101 #include <asm/cacheflush.h>
 102
 103 #define CREATE_TRACE_POINTS
 104 #include <trace/events/initcall.h>
 105
 106 static int kernel_init(void *);
 107
 108 extern void init_IRQ(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         size_t len = strlen(boot_command_line) + 1;
 378
 379         saved_command_line = memblock_alloc(len, SMP_CACHE_BYTES);
 380         if (!saved_command_line)
 381                 panic("%s: Failed to allocate %zu bytes\n", __func__, len);
 382
 383         initcall_command_line = memblock_alloc(len, SMP_CACHE_BYTES);
 384         if (!initcall_command_line)
 385                 panic("%s: Failed to allocate %zu bytes\n", __func__, len);
 386
 387         static_command_line = memblock_alloc(len, SMP_CACHE_BYTES);
 388         if (!static_command_line)
 389                 panic("%s: Failed to allocate %zu bytes\n", __func__, len);
 390
 391         strcpy(saved_command_line, boot_command_line);
 392         strcpy(static_command_line, command_line);
 393 }
 394
 395 /*
 396  * We need to finalize in a non-__init function or else race conditions
 397  * between the root thread and the init thread may cause start_kernel to
 398  * be reaped by free_initmem before the root thread has proceeded to
 399  * cpu_idle.
 400  *
 401  * gcc-3.4 accidentally inlines this function, so use noinline.
 402  */
 403
 404 static __initdata DECLARE_COMPLETION(kthreadd_done);
 405
 406 noinline void __ref rest_init(void)
 407 {
 408         struct task_struct *tsk;
 409         int pid;
 410
 411         rcu_scheduler_starting();
 412         /*
 413          * We need to spawn init first so that it obtains pid 1, however
 414          * the init task will end up wanting to create kthreads, which, if
 415          * we schedule it before we create kthreadd, will OOPS.
 416          */
 417         pid = kernel_thread(kernel_init, NULL, CLONE_FS);
 418         /*
 419          * Pin init on the boot CPU. Task migration is not properly working
 420          * until sched_init_smp() has been run. It will set the allowed
 421          * CPUs for init to the non isolated CPUs.
 422          */
 423         rcu_read_lock();
 424         tsk = find_task_by_pid_ns(pid, &init_pid_ns);
 425         set_cpus_allowed_ptr(tsk, cpumask_of(smp_processor_id()));
 426         rcu_read_unlock();
 427
 428         numa_default_policy();
 429         pid = kernel_thread(kthreadd, NULL, CLONE_FS | CLONE_FILES);
 430         rcu_read_lock();
 431         kthreadd_task = find_task_by_pid_ns(pid, &init_pid_ns);
 432         rcu_read_unlock();
 433
 434         /*
 435          * Enable might_sleep() and smp_processor_id() checks.
 436          * They cannot be enabled earlier because with CONFIG_PREEMPTION=y
 437          * kernel_thread() would trigger might_sleep() splats. With
 438          * CONFIG_PREEMPT_VOLUNTARY=y the init task might have scheduled
 439          * already, but it's stuck on the kthreadd_done completion.
 440          */
 441         system_state = SYSTEM_SCHEDULING;
 442
 443         complete(&kthreadd_done);
 444
 445         /*
 446          * The boot idle thread must execute schedule()
 447          * at least once to get things moving:
 448          */
 449         schedule_preempt_disabled();
 450         /* Call into cpu_idle with preempt disabled */
 451         cpu_startup_entry(CPUHP_ONLINE);
 452 }
 453
 454 /* Check for early params. */
 455 static int __init do_early_param(char *param, char *val,
 456                                  const char *unused, void *arg)
 457 {
 458         const struct obs_kernel_param *p;
 459
 460         for (p = __setup_start; p < __setup_end; p++) {
 461                 if ((p->early && parameq(param, p->str)) ||
 462                     (strcmp(param, "console") == 0 &&
 463                      strcmp(p->str, "earlycon") == 0)
 464                 ) {
 465                         if (p->setup_func(val) != 0)
 466                                 pr_warn("Malformed early option '%s'\n", param);
 467                 }
 468         }
 469         /* We accept everything at this stage. */
 470         return 0;
 471 }
 472
 473 void __init parse_early_options(char *cmdline)
 474 {
 475         parse_args("early options", cmdline, NULL, 0, 0, 0, NULL,
 476                    do_early_param);
 477 }
 478
 479 /* Arch code calls this early on, or if not, just before other parsing. */
 480 void __init parse_early_param(void)
 481 {
 482         static int done __initdata;
 483         static char tmp_cmdline[COMMAND_LINE_SIZE] __initdata;
 484
 485         if (done)
 486                 return;
 487
 488         /* All fall through to do_early_param. */
 489         strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);
 490         parse_early_options(tmp_cmdline);
 491         done = 1;
 492 }
 493
 494 void __init __weak arch_post_acpi_subsys_init(void) { }
 495
 496 void __init __weak smp_setup_processor_id(void)
 497 {
 498 }
 499
 500 # if THREAD_SIZE >= PAGE_SIZE
 501 void __init __weak thread_stack_cache_init(void)
 502 {
 503 }
 504 #endif
 505
 506 void __init __weak mem_encrypt_init(void) { }
 507
 508 void __init __weak poking_init(void) { }
 509
 510 void __init __weak pgtable_cache_init(void) { }
 511
 512 bool initcall_debug;
 513 core_param(initcall_debug, initcall_debug, bool, 0644);
 514
 515 #ifdef TRACEPOINTS_ENABLED
 516 static void __init initcall_debug_enable(void);
 517 #else
 518 static inline void initcall_debug_enable(void)
 519 {
 520 }
 521 #endif
 522
 523 /* Report memory auto-initialization states for this boot. */
 524 static void __init report_meminit(void)
 525 {
 526         const char *stack;
 527
 528         if (IS_ENABLED(CONFIG_INIT_STACK_ALL))
 529                 stack = "all";
 530         else if (IS_ENABLED(CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL))
 531                 stack = "byref_all";
 532         else if (IS_ENABLED(CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF))
 533                 stack = "byref";
 534         else if (IS_ENABLED(CONFIG_GCC_PLUGIN_STRUCTLEAK_USER))
 535                 stack = "__user";
 536         else
 537                 stack = "off";
 538
 539         pr_info("mem auto-init: stack:%s, heap alloc:%s, heap free:%s\n",
 540                 stack, want_init_on_alloc(GFP_KERNEL) ? "on" : "off",
 541                 want_init_on_free() ? "on" : "off");
 542         if (want_init_on_free())
 543                 pr_info("mem auto-init: clearing system memory may take some time...\n");
 544 }
 545
 546 /*
 547  * Set up kernel memory allocators
 548  */
 549 static void __init mm_init(void)
 550 {
 551         /*
 552          * page_ext requires contiguous pages,
 553          * bigger than MAX_ORDER unless SPARSEMEM.
 554          */
 555         page_ext_init_flatmem();
 556         init_debug_pagealloc();
 557         report_meminit();
 558         mem_init();
 559         kmem_cache_init();
 560         kmemleak_init();
 561         pgtable_init();
 562         debug_objects_mem_init();
 563         vmalloc_init();
 564         ioremap_huge_init();
 565         /* Should be run before the first non-init thread is created */
 566         init_espfix_bsp();
 567         /* Should be run after espfix64 is set up. */
 568         pti_init();
 569 }
 570
 571 void __init __weak arch_call_rest_init(void)
 572 {
 573         rest_init();
 574 }
 575
 576 asmlinkage __visible void __init start_kernel(void)
 577 {
 578         char *command_line;
 579         char *after_dashes;
 580
 581         set_task_stack_end_magic(&init_task);
 582         smp_setup_processor_id();
 583         debug_objects_early_init();
 584
 585         cgroup_init_early();
 586
 587         local_irq_disable();
 588         early_boot_irqs_disabled = true;
 589
 590         /*
 591          * Interrupts are still disabled. Do necessary setups, then
 592          * enable them.
 593          */
 594         boot_cpu_init();
 595         page_address_init();
 596         pr_notice("%s", linux_banner);
 597         early_security_init();
 598         setup_arch(&command_line);
 599         setup_command_line(command_line);
 600         setup_nr_cpu_ids();
 601         setup_per_cpu_areas();
 602         smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */
 603         boot_cpu_hotplug_init();
 604
 605         build_all_zonelists(NULL);
 606         page_alloc_init();
 607
 608         pr_notice("Kernel command line: %s\n", boot_command_line);
 609         /* parameters may set static keys */
 610         jump_label_init();
 611         parse_early_param();
 612         after_dashes = parse_args("Booting kernel",
 613                                   static_command_line, __start___param,
 614                                   __stop___param - __start___param,
 615                                   -1, -1, NULL, &unknown_bootoption);
 616         if (!IS_ERR_OR_NULL(after_dashes))
 617                 parse_args("Setting init args", after_dashes, NULL, 0, -1, -1,
 618                            NULL, set_init_arg);
 619
 620         /*
 621          * These use large bootmem allocations and must precede
 622          * kmem_cache_init()
 623          */
 624         setup_log_buf(0);
 625         vfs_caches_init_early();
 626         sort_main_extable();
 627         trap_init();
 628         mm_init();
 629
 630         ftrace_init();
 631
 632         /* trace_printk can be enabled here */
 633         early_trace_init();
 634
 635         /*
 636          * Set up the scheduler prior starting any interrupts (such as the
 637          * timer interrupt). Full topology setup happens at smp_init()
 638          * time - but meanwhile we still have a functioning scheduler.
 639          */
 640         sched_init();
 641         /*
 642          * Disable preemption - early bootup scheduling is extremely
 643          * fragile until we cpu_idle() for the first time.
 644          */
 645         preempt_disable();
 646         if (WARN(!irqs_disabled(),
 647                  "Interrupts were enabled *very* early, fixing it\n"))
 648                 local_irq_disable();
 649         radix_tree_init();
 650
 651         /*
 652          * Set up housekeeping before setting up workqueues to allow the unbound
 653          * workqueue to take non-housekeeping into account.
 654          */
 655         housekeeping_init();
 656
 657         /*
 658          * Allow workqueue creation and work item queueing/cancelling
 659          * early.  Work item execution depends on kthreads and starts after
 660          * workqueue_init().
 661          */
 662         workqueue_init_early();
 663
 664         rcu_init();
 665
 666         /* Trace events are available after this */
 667         trace_init();
 668
 669         if (initcall_debug)
 670                 initcall_debug_enable();
 671
 672         context_tracking_init();
 673         /* init some links before init_ISA_irqs() */
 674         early_irq_init();
 675         init_IRQ();
 676         tick_init();
 677         rcu_init_nohz();
 678         init_timers();
 679         hrtimers_init();
 680         softirq_init();
 681         timekeeping_init();
 682
 683         /*
 684          * For best initial stack canary entropy, prepare it after:
 685          * - setup_arch() for any UEFI RNG entropy and boot cmdline access
 686          * - timekeeping_init() for ktime entropy used in rand_initialize()
 687          * - rand_initialize() to get any arch-specific entropy like RDRAND
 688          * - add_latent_entropy() to get any latent entropy
 689          * - adding command line entropy
 690          */
 691         rand_initialize();
 692         add_latent_entropy();
 693         add_device_randomness(command_line, strlen(command_line));
 694         boot_init_stack_canary();
 695
 696         time_init();
 697         perf_event_init();
 698         profile_init();
 699         call_function_init();
 700         WARN(!irqs_disabled(), "Interrupts were enabled early\n");
 701
 702         early_boot_irqs_disabled = false;
 703         local_irq_enable();
 704
 705         kmem_cache_init_late();
 706
 707         /*
 708          * HACK ALERT! This is early. We're enabling the console before
 709          * we've done PCI setups etc, and console_init() must be aware of
 710          * this. But we do want output early, in case something goes wrong.
 711          */
 712         console_init();
 713         if (panic_later)
 714                 panic("Too many boot %s vars at `%s'", panic_later,
 715                       panic_param);
 716
 717         lockdep_init();
 718
 719         /*
 720          * Need to run this when irqs are enabled, because it wants
 721          * to self-test [hard/soft]-irqs on/off lock inversion bugs
 722          * too:
 723          */
 724         locking_selftest();
 725
 726         /*
 727          * This needs to be called before any devices perform DMA
 728          * operations that might use the SWIOTLB bounce buffers. It will
 729          * mark the bounce buffers as decrypted so that their usage will
 730          * not cause "plain-text" data to be decrypted when accessed.
 731          */
 732         mem_encrypt_init();
 733
 734 #ifdef CONFIG_BLK_DEV_INITRD
 735         if (initrd_start && !initrd_below_start_ok &&
 736             page_to_pfn(virt_to_page((void *)initrd_start)) < min_low_pfn) {
 737                 pr_crit("initrd overwritten (0x%08lx < 0x%08lx) - disabling it.\n",
 738                     page_to_pfn(virt_to_page((void *)initrd_start)),
 739                     min_low_pfn);
 740                 initrd_start = 0;
 741         }
 742 #endif
 743         setup_per_cpu_pageset();
 744         numa_policy_init();
 745         acpi_early_init();
 746         if (late_time_init)
 747                 late_time_init();
 748         sched_clock_init();
 749         calibrate_delay();
 750         pid_idr_init();
 751         anon_vma_init();
 752 #ifdef CONFIG_X86
 753         if (efi_enabled(EFI_RUNTIME_SERVICES))
 754                 efi_enter_virtual_mode();
 755 #endif
 756         thread_stack_cache_init();
 757         cred_init();
 758         fork_init();
 759         proc_caches_init();
 760         uts_ns_init();
 761         buffer_init();
 762         key_init();
 763         security_init();
 764         dbg_late_init();
 765         vfs_caches_init();
 766         pagecache_init();
 767         signals_init();
 768         seq_file_init();
 769         proc_root_init();
 770         nsfs_init();
 771         cpuset_init();
 772         cgroup_init();
 773         taskstats_init_early();
 774         delayacct_init();
 775
 776         poking_init();
 777         check_bugs();
 778
 779         acpi_subsystem_init();
 780         arch_post_acpi_subsys_init();
 781         sfi_init_late();
 782
 783         /* Do the rest non-__init'ed, we're now alive */
 784         arch_call_rest_init();
 785
 786         prevent_tail_call_optimization();
 787 }
 788
 789 /* Call all constructor functions linked into the kernel. */
 790 static void __init do_ctors(void)
 791 {
 792 #ifdef CONFIG_CONSTRUCTORS
 793         ctor_fn_t *fn = (ctor_fn_t *) __ctors_start;
 794
 795         for (; fn < (ctor_fn_t *) __ctors_end; fn++)
 796                 (*fn)();
 797 #endif
 798 }
 799
 800 #ifdef CONFIG_KALLSYMS
 801 struct blacklist_entry {
 802         struct list_head next;
 803         char *buf;
 804 };
 805
 806 static __initdata_or_module LIST_HEAD(blacklisted_initcalls);
 807
 808 static int __init initcall_blacklist(char *str)
 809 {
 810         char *str_entry;
 811         struct blacklist_entry *entry;
 812
 813         /* str argument is a comma-separated list of functions */
 814         do {
 815                 str_entry = strsep(&str, ",");
 816                 if (str_entry) {
 817                         pr_debug("blacklisting initcall %s\n", str_entry);
 818                         entry = memblock_alloc(sizeof(*entry),
 819                                                SMP_CACHE_BYTES);
 820                         if (!entry)
 821                                 panic("%s: Failed to allocate %zu bytes\n",
 822                                       __func__, sizeof(*entry));
 823                         entry->buf = memblock_alloc(strlen(str_entry) + 1,
 824                                                     SMP_CACHE_BYTES);
 825                         if (!entry->buf)
 826                                 panic("%s: Failed to allocate %zu bytes\n",
 827                                       __func__, strlen(str_entry) + 1);
 828                         strcpy(entry->buf, str_entry);
 829                         list_add(&entry->next, &blacklisted_initcalls);
 830                 }
 831         } while (str_entry);
 832
 833         return 0;
 834 }
 835
 836 static bool __init_or_module initcall_blacklisted(initcall_t fn)
 837 {
 838         struct blacklist_entry *entry;
 839         char fn_name[KSYM_SYMBOL_LEN];
 840         unsigned long addr;
 841
 842         if (list_empty(&blacklisted_initcalls))
 843                 return false;
 844
 845         addr = (unsigned long) dereference_function_descriptor(fn);
 846         sprint_symbol_no_offset(fn_name, addr);
 847
 848         /*
 849          * fn will be "function_name [module_name]" where [module_name] is not
 850          * displayed for built-in init functions.  Strip off the [module_name].
 851          */
 852         strreplace(fn_name, ' ', '\0');
 853
 854         list_for_each_entry(entry, &blacklisted_initcalls, next) {
 855                 if (!strcmp(fn_name, entry->buf)) {
 856                         pr_debug("initcall %s blacklisted\n", fn_name);
 857                         return true;
 858                 }
 859         }
 860
 861         return false;
 862 }
 863 #else
 864 static int __init initcall_blacklist(char *str)
 865 {
 866         pr_warn("initcall_blacklist requires CONFIG_KALLSYMS\n");
 867         return 0;
 868 }
 869
 870 static bool __init_or_module initcall_blacklisted(initcall_t fn)
 871 {
 872         return false;
 873 }
 874 #endif
 875 __setup("initcall_blacklist=", initcall_blacklist);
 876
 877 static __init_or_module void
 878 trace_initcall_start_cb(void *data, initcall_t fn)
 879 {
 880         ktime_t *calltime = (ktime_t *)data;
 881
 882         printk(KERN_DEBUG "calling  %pS @ %i\n", fn, task_pid_nr(current));
 883         *calltime = ktime_get();
 884 }
 885
 886 static __init_or_module void
 887 trace_initcall_finish_cb(void *data, initcall_t fn, int ret)
 888 {
 889         ktime_t *calltime = (ktime_t *)data;
 890         ktime_t delta, rettime;
 891         unsigned long long duration;
 892
 893         rettime = ktime_get();
 894         delta = ktime_sub(rettime, *calltime);
 895         duration = (unsigned long long) ktime_to_ns(delta) >> 10;
 896         printk(KERN_DEBUG "initcall %pS returned %d after %lld usecs\n",
 897                  fn, ret, duration);
 898 }
 899
 900 static ktime_t initcall_calltime;
 901
 902 #ifdef TRACEPOINTS_ENABLED
 903 static void __init initcall_debug_enable(void)
 904 {
 905         int ret;
 906
 907         ret = register_trace_initcall_start(trace_initcall_start_cb,
 908                                             &initcall_calltime);
 909         ret |= register_trace_initcall_finish(trace_initcall_finish_cb,
 910                                               &initcall_calltime);
 911         WARN(ret, "Failed to register initcall tracepoints\n");
 912 }
 913 # define do_trace_initcall_start        trace_initcall_start
 914 # define do_trace_initcall_finish       trace_initcall_finish
 915 #else
 916 static inline void do_trace_initcall_start(initcall_t fn)
 917 {
 918         if (!initcall_debug)
 919                 return;
 920         trace_initcall_start_cb(&initcall_calltime, fn);
 921 }
 922 static inline void do_trace_initcall_finish(initcall_t fn, int ret)
 923 {
 924         if (!initcall_debug)
 925                 return;
 926         trace_initcall_finish_cb(&initcall_calltime, fn, ret);
 927 }
 928 #endif /* !TRACEPOINTS_ENABLED */
 929
 930 int __init_or_module do_one_initcall(initcall_t fn)
 931 {
 932         int count = preempt_count();
 933         char msgbuf[64];
 934         int ret;
 935
 936         if (initcall_blacklisted(fn))
 937                 return -EPERM;
 938
 939         do_trace_initcall_start(fn);
 940         ret = fn();
 941         do_trace_initcall_finish(fn, ret);
 942
 943         msgbuf[0] = 0;
 944
 945         if (preempt_count() != count) {
 946                 sprintf(msgbuf, "preemption imbalance ");
 947                 preempt_count_set(count);
 948         }
 949         if (irqs_disabled()) {
 950                 strlcat(msgbuf, "disabled interrupts ", sizeof(msgbuf));
 951                 local_irq_enable();
 952         }
 953         WARN(msgbuf[0], "initcall %pS returned with %s\n", fn, msgbuf);
 954
 955         add_latent_entropy();
 956         return ret;
 957 }
 958
 959
 960 extern initcall_entry_t __initcall_start[];
 961 extern initcall_entry_t __initcall0_start[];
 962 extern initcall_entry_t __initcall1_start[];
 963 extern initcall_entry_t __initcall2_start[];
 964 extern initcall_entry_t __initcall3_start[];
 965 extern initcall_entry_t __initcall4_start[];
 966 extern initcall_entry_t __initcall5_start[];
 967 extern initcall_entry_t __initcall6_start[];
 968 extern initcall_entry_t __initcall7_start[];
 969 extern initcall_entry_t __initcall_end[];
 970
 971 static initcall_entry_t *initcall_levels[] __initdata = {
 972         __initcall0_start,
 973         __initcall1_start,
 974         __initcall2_start,
 975         __initcall3_start,
 976         __initcall4_start,
 977         __initcall5_start,
 978         __initcall6_start,
 979         __initcall7_start,
 980         __initcall_end,
 981 };
 982
 983 /* Keep these in sync with initcalls in include/linux/init.h */
 984 static const char *initcall_level_names[] __initdata = {
 985         "pure",
 986         "core",
 987         "postcore",
 988         "arch",
 989         "subsys",
 990         "fs",
 991         "device",
 992         "late",
 993 };
 994
 995 static void __init do_initcall_level(int level)
 996 {
 997         initcall_entry_t *fn;
 998
 999         strcpy(initcall_command_line, saved_command_line);
1000         parse_args(initcall_level_names[level],
1001                    initcall_command_line, __start___param,
1002                    __stop___param - __start___param,
1003                    level, level,
1004                    NULL, &repair_env_string);
1005
1006         trace_initcall_level(initcall_level_names[level]);
1007         for (fn = initcall_levels[level]; fn < initcall_levels[level+1]; fn++)
1008                 do_one_initcall(initcall_from_entry(fn));
1009 }
1010
1011 static void __init do_initcalls(void)
1012 {
1013         int level;
1014
1015         for (level = 0; level < ARRAY_SIZE(initcall_levels) - 1; level++)
1016                 do_initcall_level(level);
1017 }
1018
1019 /*
1020  * Ok, the machine is now initialized. None of the devices
1021  * have been touched yet, but the CPU subsystem is up and
1022  * running, and memory and process management works.
1023  *
1024  * Now we can finally start doing some real work..
1025  */
1026 static void __init do_basic_setup(void)
1027 {
1028         cpuset_init_smp();
1029         driver_init();
1030         init_irq_proc();
1031         do_ctors();
1032         usermodehelper_enable();
1033         do_initcalls();
1034 }
1035
1036 static void __init do_pre_smp_initcalls(void)
1037 {
1038         initcall_entry_t *fn;
1039
1040         trace_initcall_level("early");
1041         for (fn = __initcall_start; fn < __initcall0_start; fn++)
1042                 do_one_initcall(initcall_from_entry(fn));
1043 }
1044
1045 static int run_init_process(const char *init_filename)
1046 {
1047         argv_init[0] = init_filename;
1048         pr_info("Run %s as init process\n", init_filename);
1049         return do_execve(getname_kernel(init_filename),
1050                 (const char __user *const __user *)argv_init,
1051                 (const char __user *const __user *)envp_init);
1052 }
1053
1054 static int try_to_run_init_process(const char *init_filename)
1055 {
1056         int ret;
1057
1058         ret = run_init_process(init_filename);
1059
1060         if (ret && ret != -ENOENT) {
1061                 pr_err("Starting init: %s exists but couldn't execute it (error %d)\n",
1062                        init_filename, ret);
1063         }
1064
1065         return ret;
1066 }
1067
1068 static noinline void __init kernel_init_freeable(void);
1069
1070 #if defined(CONFIG_STRICT_KERNEL_RWX) || defined(CONFIG_STRICT_MODULE_RWX)
1071 bool rodata_enabled __ro_after_init = true;
1072 static int __init set_debug_rodata(char *str)
1073 {
1074         return strtobool(str, &rodata_enabled);
1075 }
1076 __setup("rodata=", set_debug_rodata);
1077 #endif
1078
1079 #ifdef CONFIG_STRICT_KERNEL_RWX
1080 static void mark_readonly(void)
1081 {
1082         if (rodata_enabled) {
1083                 /*
1084                  * load_module() results in W+X mappings, which are cleaned
1085                  * up with call_rcu().  Let's make sure that queued work is
1086                  * flushed so that we don't hit false positives looking for
1087                  * insecure pages which are W+X.
1088                  */
1089                 rcu_barrier();
1090                 mark_rodata_ro();
1091                 rodata_test();
1092         } else
1093                 pr_info("Kernel memory protection disabled.\n");
1094 }
1095 #else
1096 static inline void mark_readonly(void)
1097 {
1098         pr_warn("This architecture does not have kernel memory protection.\n");
1099 }
1100 #endif
1101
1102 void __weak free_initmem(void)
1103 {
1104         free_initmem_default(POISON_FREE_INITMEM);
1105 }
1106
1107 static int __ref kernel_init(void *unused)
1108 {
1109         int ret;
1110
1111         kernel_init_freeable();
1112         /* need to finish all async __init code before freeing the memory */
1113         async_synchronize_full();
1114         ftrace_free_init_mem();
1115         free_initmem();
1116         mark_readonly();
1117
1118         /*
1119          * Kernel mappings are now finalized - update the userspace page-table
1120          * to finalize PTI.
1121          */
1122         pti_finalize();
1123
1124         system_state = SYSTEM_RUNNING;
1125         numa_default_policy();
1126
1127         rcu_end_inkernel_boot();
1128
1129         if (ramdisk_execute_command) {
1130                 ret = run_init_process(ramdisk_execute_command);
1131                 if (!ret)
1132                         return 0;
1133                 pr_err("Failed to execute %s (error %d)\n",
1134                        ramdisk_execute_command, ret);
1135         }
1136
1137         /*
1138          * We try each of these until one succeeds.
1139          *
1140          * The Bourne shell can be used instead of init if we are
1141          * trying to recover a really broken machine.
1142          */
1143         if (execute_command) {
1144                 ret = run_init_process(execute_command);
1145                 if (!ret)
1146                         return 0;
1147                 panic("Requested init %s failed (error %d).",
1148                       execute_command, ret);
1149         }
1150         if (!try_to_run_init_process("/sbin/init") ||
1151             !try_to_run_init_process("/etc/init") ||
1152             !try_to_run_init_process("/bin/init") ||
1153             !try_to_run_init_process("/bin/sh"))
1154                 return 0;
1155
1156         panic("No working init found.  Try passing init= option to kernel. "
1157               "See Linux Documentation/admin-guide/init.rst for guidance.");
1158 }
1159
1160 static noinline void __init kernel_init_freeable(void)
1161 {
1162         /*
1163          * Wait until kthreadd is all set-up.
1164          */
1165         wait_for_completion(&kthreadd_done);
1166
1167         /* Now the scheduler is fully set up and can do blocking allocations */
1168         gfp_allowed_mask = __GFP_BITS_MASK;
1169
1170         /*
1171          * init can allocate pages on any node
1172          */
1173         set_mems_allowed(node_states[N_MEMORY]);
1174
1175         cad_pid = task_pid(current);
1176
1177         smp_prepare_cpus(setup_max_cpus);
1178
1179         workqueue_init();
1180
1181         init_mm_internals();
1182
1183         do_pre_smp_initcalls();
1184         lockup_detector_init();
1185
1186         smp_init();
1187         sched_init_smp();
1188
1189         page_alloc_init_late();
1190         /* Initialize page ext after all struct pages are initialized. */
1191         page_ext_init();
1192
1193         do_basic_setup();
1194
1195         /* Open the /dev/console on the rootfs, this should never fail */
1196         if (ksys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0)
1197                 pr_err("Warning: unable to open an initial console.\n");
1198
1199         (void) ksys_dup(0);
1200         (void) ksys_dup(0);
1201         /*
1202          * check if there is an early userspace init.  If yes, let it do all
1203          * the work
1204          */
1205
1206         if (!ramdisk_execute_command)
1207                 ramdisk_execute_command = "/init";
1208
1209         if (ksys_access((const char __user *)
1210                         ramdisk_execute_command, 0) != 0) {
1211                 ramdisk_execute_command = NULL;
1212                 prepare_namespace();
1213         }
1214
1215         /*
1216          * Ok, we have completed the initial bootup, and
1217          * we're essentially up and running. Get rid of the
1218          * initmem segments and start the user-mode stuff..
1219          *
1220          * rootfs is available now, try loading the public keys
1221          * and default modules
1222          */
1223
1224         integrity_load_keys();
1225 }