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/bootconfig.h>
  32 #include <linux/console.h>
  33 #include <linux/nmi.h>
  34 #include <linux/percpu.h>
  35 #include <linux/kmod.h>
  36 #include <linux/kprobes.h>
  37 #include <linux/vmalloc.h>
  38 #include <linux/kernel_stat.h>
  39 #include <linux/start_kernel.h>
  40 #include <linux/security.h>
  41 #include <linux/smp.h>
  42 #include <linux/profile.h>
  43 #include <linux/rcupdate.h>
  44 #include <linux/moduleparam.h>
  45 #include <linux/kallsyms.h>
  46 #include <linux/writeback.h>
  47 #include <linux/cpu.h>
  48 #include <linux/cpuset.h>
  49 #include <linux/cgroup.h>
  50 #include <linux/efi.h>
  51 #include <linux/tick.h>
  52 #include <linux/sched/isolation.h>
  53 #include <linux/interrupt.h>
  54 #include <linux/taskstats_kern.h>
  55 #include <linux/delayacct.h>
  56 #include <linux/unistd.h>
  57 #include <linux/utsname.h>
  58 #include <linux/rmap.h>
  59 #include <linux/mempolicy.h>
  60 #include <linux/key.h>
  61 #include <linux/page_ext.h>
  62 #include <linux/debug_locks.h>
  63 #include <linux/debugobjects.h>
  64 #include <linux/lockdep.h>
  65 #include <linux/kmemleak.h>
  66 #include <linux/padata.h>
  67 #include <linux/pid_namespace.h>
  68 #include <linux/device/driver.h>
  69 #include <linux/kthread.h>
  70 #include <linux/sched.h>
  71 #include <linux/sched/init.h>
  72 #include <linux/signal.h>
  73 #include <linux/idr.h>
  74 #include <linux/kgdb.h>
  75 #include <linux/ftrace.h>
  76 #include <linux/async.h>
  77 #include <linux/shmem_fs.h>
  78 #include <linux/slab.h>
  79 #include <linux/perf_event.h>
  80 #include <linux/ptrace.h>
  81 #include <linux/pti.h>
  82 #include <linux/blkdev.h>
  83 #include <linux/elevator.h>
  84 #include <linux/sched/clock.h>
  85 #include <linux/sched/task.h>
  86 #include <linux/sched/task_stack.h>
  87 #include <linux/context_tracking.h>
  88 #include <linux/random.h>
  89 #include <linux/list.h>
  90 #include <linux/integrity.h>
  91 #include <linux/proc_ns.h>
  92 #include <linux/io.h>
  93 #include <linux/cache.h>
  94 #include <linux/rodata_test.h>
  95 #include <linux/jump_label.h>
  96 #include <linux/mem_encrypt.h>
  97 #include <linux/kcsan.h>
  98 #include <linux/init_syscalls.h>
  99
 100 #include <asm/io.h>
 101 #include <asm/bugs.h>
 102 #include <asm/setup.h>
 103 #include <asm/sections.h>
 104 #include <asm/cacheflush.h>
 105
 106 #define CREATE_TRACE_POINTS
 107 #include <trace/events/initcall.h>
 108
 109 #include <kunit/test.h>
 110
 111 static int kernel_init(void *);
 112
 113 extern void init_IRQ(void);
 114 extern void radix_tree_init(void);
 115
 116 /*
 117  * Debug helper: via this flag we know that we are in 'early bootup code'
 118  * where only the boot processor is running with IRQ disabled.  This means
 119  * two things - IRQ must not be enabled before the flag is cleared and some
 120  * operations which are not allowed with IRQ disabled are allowed while the
 121  * flag is set.
 122  */
 123 bool early_boot_irqs_disabled __read_mostly;
 124
 125 enum system_states system_state __read_mostly;
 126 EXPORT_SYMBOL(system_state);
 127
 128 /*
 129  * Boot command-line arguments
 130  */
 131 #define MAX_INIT_ARGS CONFIG_INIT_ENV_ARG_LIMIT
 132 #define MAX_INIT_ENVS CONFIG_INIT_ENV_ARG_LIMIT
 133
 134 extern void time_init(void);
 135 /* Default late time init is NULL. archs can override this later. */
 136 void (*__initdata late_time_init)(void);
 137
 138 /* Untouched command line saved by arch-specific code. */
 139 char __initdata boot_command_line[COMMAND_LINE_SIZE];
 140 /* Untouched saved command line (eg. for /proc) */
 141 char *saved_command_line;
 142 /* Command line for parameter parsing */
 143 static char *static_command_line;
 144 /* Untouched extra command line */
 145 static char *extra_command_line;
 146 /* Extra init arguments */
 147 static char *extra_init_args;
 148
 149 #ifdef CONFIG_BOOT_CONFIG
 150 /* Is bootconfig on command line? */
 151 static bool bootconfig_found;
 152 static bool initargs_found;
 153 #else
 154 # define bootconfig_found false
 155 # define initargs_found false
 156 #endif
 157
 158 static char *execute_command;
 159 static char *ramdisk_execute_command = "/init";
 160
 161 /*
 162  * Used to generate warnings if static_key manipulation functions are used
 163  * before jump_label_init is called.
 164  */
 165 bool static_key_initialized __read_mostly;
 166 EXPORT_SYMBOL_GPL(static_key_initialized);
 167
 168 /*
 169  * If set, this is an indication to the drivers that reset the underlying
 170  * device before going ahead with the initialization otherwise driver might
 171  * rely on the BIOS and skip the reset operation.
 172  *
 173  * This is useful if kernel is booting in an unreliable environment.
 174  * For ex. kdump situation where previous kernel has crashed, BIOS has been
 175  * skipped and devices will be in unknown state.
 176  */
 177 unsigned int reset_devices;
 178 EXPORT_SYMBOL(reset_devices);
 179
 180 static int __init set_reset_devices(char *str)
 181 {
 182         reset_devices = 1;
 183         return 1;
 184 }
 185
 186 __setup("reset_devices", set_reset_devices);
 187
 188 static const char *argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
 189 const char *envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, };
 190 static const char *panic_later, *panic_param;
 191
 192 extern const struct obs_kernel_param __setup_start[], __setup_end[];
 193
 194 static bool __init obsolete_checksetup(char *line)
 195 {
 196         const struct obs_kernel_param *p;
 197         bool had_early_param = false;
 198
 199         p = __setup_start;
 200         do {
 201                 int n = strlen(p->str);
 202                 if (parameqn(line, p->str, n)) {
 203                         if (p->early) {
 204                                 /* Already done in parse_early_param?
 205                                  * (Needs exact match on param part).
 206                                  * Keep iterating, as we can have early
 207                                  * params and __setups of same names 8( */
 208                                 if (line[n] == '\0' || line[n] == '=')
 209                                         had_early_param = true;
 210                         } else if (!p->setup_func) {
 211                                 pr_warn("Parameter %s is obsolete, ignored\n",
 212                                         p->str);
 213                                 return true;
 214                         } else if (p->setup_func(line + n))
 215                                 return true;
 216                 }
 217                 p++;
 218         } while (p < __setup_end);
 219
 220         return had_early_param;
 221 }
 222
 223 /*
 224  * This should be approx 2 Bo*oMips to start (note initial shift), and will
 225  * still work even if initially too large, it will just take slightly longer
 226  */
 227 unsigned long loops_per_jiffy = (1<<12);
 228 EXPORT_SYMBOL(loops_per_jiffy);
 229
 230 static int __init debug_kernel(char *str)
 231 {
 232         console_loglevel = CONSOLE_LOGLEVEL_DEBUG;
 233         return 0;
 234 }
 235
 236 static int __init quiet_kernel(char *str)
 237 {
 238         console_loglevel = CONSOLE_LOGLEVEL_QUIET;
 239         return 0;
 240 }
 241
 242 early_param("debug", debug_kernel);
 243 early_param("quiet", quiet_kernel);
 244
 245 static int __init loglevel(char *str)
 246 {
 247         int newlevel;
 248
 249         /*
 250          * Only update loglevel value when a correct setting was passed,
 251          * to prevent blind crashes (when loglevel being set to 0) that
 252          * are quite hard to debug
 253          */
 254         if (get_option(&str, &newlevel)) {
 255                 console_loglevel = newlevel;
 256                 return 0;
 257         }
 258
 259         return -EINVAL;
 260 }
 261
 262 early_param("loglevel", loglevel);
 263
 264 #ifdef CONFIG_BLK_DEV_INITRD
 265 static void * __init get_boot_config_from_initrd(u32 *_size, u32 *_csum)
 266 {
 267         u32 size, csum;
 268         char *data;
 269         u32 *hdr;
 270         int i;
 271
 272         if (!initrd_end)
 273                 return NULL;
 274
 275         data = (char *)initrd_end - BOOTCONFIG_MAGIC_LEN;
 276         /*
 277          * Since Grub may align the size of initrd to 4, we must
 278          * check the preceding 3 bytes as well.
 279          */
 280         for (i = 0; i < 4; i++) {
 281                 if (!memcmp(data, BOOTCONFIG_MAGIC, BOOTCONFIG_MAGIC_LEN))
 282                         goto found;
 283                 data--;
 284         }
 285         return NULL;
 286
 287 found:
 288         hdr = (u32 *)(data - 8);
 289         size = le32_to_cpu(hdr[0]);
 290         csum = le32_to_cpu(hdr[1]);
 291
 292         data = ((void *)hdr) - size;
 293         if ((unsigned long)data < initrd_start) {
 294                 pr_err("bootconfig size %d is greater than initrd size %ld\n",
 295                         size, initrd_end - initrd_start);
 296                 return NULL;
 297         }
 298
 299         /* Remove bootconfig from initramfs/initrd */
 300         initrd_end = (unsigned long)data;
 301         if (_size)
 302                 *_size = size;
 303         if (_csum)
 304                 *_csum = csum;
 305
 306         return data;
 307 }
 308 #else
 309 static void * __init get_boot_config_from_initrd(u32 *_size, u32 *_csum)
 310 {
 311         return NULL;
 312 }
 313 #endif
 314
 315 #ifdef CONFIG_BOOT_CONFIG
 316
 317 static char xbc_namebuf[XBC_KEYLEN_MAX] __initdata;
 318
 319 #define rest(dst, end) ((end) > (dst) ? (end) - (dst) : 0)
 320
 321 static int __init xbc_snprint_cmdline(char *buf, size_t size,
 322                                       struct xbc_node *root)
 323 {
 324         struct xbc_node *knode, *vnode;
 325         char *end = buf + size;
 326         const char *val;
 327         int ret;
 328
 329         xbc_node_for_each_key_value(root, knode, val) {
 330                 ret = xbc_node_compose_key_after(root, knode,
 331                                         xbc_namebuf, XBC_KEYLEN_MAX);
 332                 if (ret < 0)
 333                         return ret;
 334
 335                 vnode = xbc_node_get_child(knode);
 336                 if (!vnode) {
 337                         ret = snprintf(buf, rest(buf, end), "%s ", xbc_namebuf);
 338                         if (ret < 0)
 339                                 return ret;
 340                         buf += ret;
 341                         continue;
 342                 }
 343                 xbc_array_for_each_value(vnode, val) {
 344                         ret = snprintf(buf, rest(buf, end), "%s=\"%s\" ",
 345                                        xbc_namebuf, val);
 346                         if (ret < 0)
 347                                 return ret;
 348                         buf += ret;
 349                 }
 350         }
 351
 352         return buf - (end - size);
 353 }
 354 #undef rest
 355
 356 /* Make an extra command line under given key word */
 357 static char * __init xbc_make_cmdline(const char *key)
 358 {
 359         struct xbc_node *root;
 360         char *new_cmdline;
 361         int ret, len = 0;
 362
 363         root = xbc_find_node(key);
 364         if (!root)
 365                 return NULL;
 366
 367         /* Count required buffer size */
 368         len = xbc_snprint_cmdline(NULL, 0, root);
 369         if (len <= 0)
 370                 return NULL;
 371
 372         new_cmdline = memblock_alloc(len + 1, SMP_CACHE_BYTES);
 373         if (!new_cmdline) {
 374                 pr_err("Failed to allocate memory for extra kernel cmdline.\n");
 375                 return NULL;
 376         }
 377
 378         ret = xbc_snprint_cmdline(new_cmdline, len + 1, root);
 379         if (ret < 0 || ret > len) {
 380                 pr_err("Failed to print extra kernel cmdline.\n");
 381                 return NULL;
 382         }
 383
 384         return new_cmdline;
 385 }
 386
 387 static u32 boot_config_checksum(unsigned char *p, u32 size)
 388 {
 389         u32 ret = 0;
 390
 391         while (size--)
 392                 ret += *p++;
 393
 394         return ret;
 395 }
 396
 397 static int __init bootconfig_params(char *param, char *val,
 398                                     const char *unused, void *arg)
 399 {
 400         if (strcmp(param, "bootconfig") == 0) {
 401                 bootconfig_found = true;
 402         }
 403         return 0;
 404 }
 405
 406 static void __init setup_boot_config(const char *cmdline)
 407 {
 408         static char tmp_cmdline[COMMAND_LINE_SIZE] __initdata;
 409         const char *msg;
 410         int pos;
 411         u32 size, csum;
 412         char *data, *copy, *err;
 413         int ret;
 414
 415         /* Cut out the bootconfig data even if we have no bootconfig option */
 416         data = get_boot_config_from_initrd(&size, &csum);
 417
 418         strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);
 419         err = parse_args("bootconfig", tmp_cmdline, NULL, 0, 0, 0, NULL,
 420                          bootconfig_params);
 421
 422         if (IS_ERR(err) || !bootconfig_found)
 423                 return;
 424
 425         /* parse_args() stops at '--' and returns an address */
 426         if (err)
 427                 initargs_found = true;
 428
 429         if (!data) {
 430                 pr_err("'bootconfig' found on command line, but no bootconfig found\n");
 431                 return;
 432         }
 433
 434         if (size >= XBC_DATA_MAX) {
 435                 pr_err("bootconfig size %d greater than max size %d\n",
 436                         size, XBC_DATA_MAX);
 437                 return;
 438         }
 439
 440         if (boot_config_checksum((unsigned char *)data, size) != csum) {
 441                 pr_err("bootconfig checksum failed\n");
 442                 return;
 443         }
 444
 445         copy = memblock_alloc(size + 1, SMP_CACHE_BYTES);
 446         if (!copy) {
 447                 pr_err("Failed to allocate memory for bootconfig\n");
 448                 return;
 449         }
 450
 451         memcpy(copy, data, size);
 452         copy[size] = '\0';
 453
 454         ret = xbc_init(copy, &msg, &pos);
 455         if (ret < 0) {
 456                 if (pos < 0)
 457                         pr_err("Failed to init bootconfig: %s.\n", msg);
 458                 else
 459                         pr_err("Failed to parse bootconfig: %s at %d.\n",
 460                                 msg, pos);
 461         } else {
 462                 pr_info("Load bootconfig: %d bytes %d nodes\n", size, ret);
 463                 /* keys starting with "kernel." are passed via cmdline */
 464                 extra_command_line = xbc_make_cmdline("kernel");
 465                 /* Also, "init." keys are init arguments */
 466                 extra_init_args = xbc_make_cmdline("init");
 467         }
 468         return;
 469 }
 470
 471 #else
 472
 473 static void __init setup_boot_config(const char *cmdline)
 474 {
 475         /* Remove bootconfig data from initrd */
 476         get_boot_config_from_initrd(NULL, NULL);
 477 }
 478
 479 static int __init warn_bootconfig(char *str)
 480 {
 481         pr_warn("WARNING: 'bootconfig' found on the kernel command line but CONFIG_BOOT_CONFIG is not set.\n");
 482         return 0;
 483 }
 484 early_param("bootconfig", warn_bootconfig);
 485
 486 #endif
 487
 488 /* Change NUL term back to "=", to make "param" the whole string. */
 489 static void __init repair_env_string(char *param, char *val)
 490 {
 491         if (val) {
 492                 /* param=val or param="val"? */
 493                 if (val == param+strlen(param)+1)
 494                         val[-1] = '=';
 495                 else if (val == param+strlen(param)+2) {
 496                         val[-2] = '=';
 497                         memmove(val-1, val, strlen(val)+1);
 498                 } else
 499                         BUG();
 500         }
 501 }
 502
 503 /* Anything after -- gets handed straight to init. */
 504 static int __init set_init_arg(char *param, char *val,
 505                                const char *unused, void *arg)
 506 {
 507         unsigned int i;
 508
 509         if (panic_later)
 510                 return 0;
 511
 512         repair_env_string(param, val);
 513
 514         for (i = 0; argv_init[i]; i++) {
 515                 if (i == MAX_INIT_ARGS) {
 516                         panic_later = "init";
 517                         panic_param = param;
 518                         return 0;
 519                 }
 520         }
 521         argv_init[i] = param;
 522         return 0;
 523 }
 524
 525 /*
 526  * Unknown boot options get handed to init, unless they look like
 527  * unused parameters (modprobe will find them in /proc/cmdline).
 528  */
 529 static int __init unknown_bootoption(char *param, char *val,
 530                                      const char *unused, void *arg)
 531 {
 532         size_t len = strlen(param);
 533
 534         repair_env_string(param, val);
 535
 536         /* Handle obsolete-style parameters */
 537         if (obsolete_checksetup(param))
 538                 return 0;
 539
 540         /* Unused module parameter. */
 541         if (strnchr(param, len, '.'))
 542                 return 0;
 543
 544         if (panic_later)
 545                 return 0;
 546
 547         if (val) {
 548                 /* Environment option */
 549                 unsigned int i;
 550                 for (i = 0; envp_init[i]; i++) {
 551                         if (i == MAX_INIT_ENVS) {
 552                                 panic_later = "env";
 553                                 panic_param = param;
 554                         }
 555                         if (!strncmp(param, envp_init[i], len+1))
 556                                 break;
 557                 }
 558                 envp_init[i] = param;
 559         } else {
 560                 /* Command line option */
 561                 unsigned int i;
 562                 for (i = 0; argv_init[i]; i++) {
 563                         if (i == MAX_INIT_ARGS) {
 564                                 panic_later = "init";
 565                                 panic_param = param;
 566                         }
 567                 }
 568                 argv_init[i] = param;
 569         }
 570         return 0;
 571 }
 572
 573 static int __init init_setup(char *str)
 574 {
 575         unsigned int i;
 576
 577         execute_command = str;
 578         /*
 579          * In case LILO is going to boot us with default command line,
 580          * it prepends "auto" before the whole cmdline which makes
 581          * the shell think it should execute a script with such name.
 582          * So we ignore all arguments entered _before_ init=... [MJ]
 583          */
 584         for (i = 1; i < MAX_INIT_ARGS; i++)
 585                 argv_init[i] = NULL;
 586         return 1;
 587 }
 588 __setup("init=", init_setup);
 589
 590 static int __init rdinit_setup(char *str)
 591 {
 592         unsigned int i;
 593
 594         ramdisk_execute_command = str;
 595         /* See "auto" comment in init_setup */
 596         for (i = 1; i < MAX_INIT_ARGS; i++)
 597                 argv_init[i] = NULL;
 598         return 1;
 599 }
 600 __setup("rdinit=", rdinit_setup);
 601
 602 #ifndef CONFIG_SMP
 603 static const unsigned int setup_max_cpus = NR_CPUS;
 604 static inline void setup_nr_cpu_ids(void) { }
 605 static inline void smp_prepare_cpus(unsigned int maxcpus) { }
 606 #endif
 607
 608 /*
 609  * We need to store the untouched command line for future reference.
 610  * We also need to store the touched command line since the parameter
 611  * parsing is performed in place, and we should allow a component to
 612  * store reference of name/value for future reference.
 613  */
 614 static void __init setup_command_line(char *command_line)
 615 {
 616         size_t len, xlen = 0, ilen = 0;
 617
 618         if (extra_command_line)
 619                 xlen = strlen(extra_command_line);
 620         if (extra_init_args)
 621                 ilen = strlen(extra_init_args) + 4; /* for " -- " */
 622
 623         len = xlen + strlen(boot_command_line) + 1;
 624
 625         saved_command_line = memblock_alloc(len + ilen, SMP_CACHE_BYTES);
 626         if (!saved_command_line)
 627                 panic("%s: Failed to allocate %zu bytes\n", __func__, len + ilen);
 628
 629         static_command_line = memblock_alloc(len, SMP_CACHE_BYTES);
 630         if (!static_command_line)
 631                 panic("%s: Failed to allocate %zu bytes\n", __func__, len);
 632
 633         if (xlen) {
 634                 /*
 635                  * We have to put extra_command_line before boot command
 636                  * lines because there could be dashes (separator of init
 637                  * command line) in the command lines.
 638                  */
 639                 strcpy(saved_command_line, extra_command_line);
 640                 strcpy(static_command_line, extra_command_line);
 641         }
 642         strcpy(saved_command_line + xlen, boot_command_line);
 643         strcpy(static_command_line + xlen, command_line);
 644
 645         if (ilen) {
 646                 /*
 647                  * Append supplemental init boot args to saved_command_line
 648                  * so that user can check what command line options passed
 649                  * to init.
 650                  */
 651                 len = strlen(saved_command_line);
 652                 if (initargs_found) {
 653                         saved_command_line[len++] = ' ';
 654                 } else {
 655                         strcpy(saved_command_line + len, " -- ");
 656                         len += 4;
 657                 }
 658
 659                 strcpy(saved_command_line + len, extra_init_args);
 660         }
 661 }
 662
 663 /*
 664  * We need to finalize in a non-__init function or else race conditions
 665  * between the root thread and the init thread may cause start_kernel to
 666  * be reaped by free_initmem before the root thread has proceeded to
 667  * cpu_idle.
 668  *
 669  * gcc-3.4 accidentally inlines this function, so use noinline.
 670  */
 671
 672 static __initdata DECLARE_COMPLETION(kthreadd_done);
 673
 674 noinline void __ref rest_init(void)
 675 {
 676         struct task_struct *tsk;
 677         int pid;
 678
 679         rcu_scheduler_starting();
 680         /*
 681          * We need to spawn init first so that it obtains pid 1, however
 682          * the init task will end up wanting to create kthreads, which, if
 683          * we schedule it before we create kthreadd, will OOPS.
 684          */
 685         pid = kernel_thread(kernel_init, NULL, CLONE_FS);
 686         /*
 687          * Pin init on the boot CPU. Task migration is not properly working
 688          * until sched_init_smp() has been run. It will set the allowed
 689          * CPUs for init to the non isolated CPUs.
 690          */
 691         rcu_read_lock();
 692         tsk = find_task_by_pid_ns(pid, &init_pid_ns);
 693         set_cpus_allowed_ptr(tsk, cpumask_of(smp_processor_id()));
 694         rcu_read_unlock();
 695
 696         numa_default_policy();
 697         pid = kernel_thread(kthreadd, NULL, CLONE_FS | CLONE_FILES);
 698         rcu_read_lock();
 699         kthreadd_task = find_task_by_pid_ns(pid, &init_pid_ns);
 700         rcu_read_unlock();
 701
 702         /*
 703          * Enable might_sleep() and smp_processor_id() checks.
 704          * They cannot be enabled earlier because with CONFIG_PREEMPTION=y
 705          * kernel_thread() would trigger might_sleep() splats. With
 706          * CONFIG_PREEMPT_VOLUNTARY=y the init task might have scheduled
 707          * already, but it's stuck on the kthreadd_done completion.
 708          */
 709         system_state = SYSTEM_SCHEDULING;
 710
 711         complete(&kthreadd_done);
 712
 713         /*
 714          * The boot idle thread must execute schedule()
 715          * at least once to get things moving:
 716          */
 717         schedule_preempt_disabled();
 718         /* Call into cpu_idle with preempt disabled */
 719         cpu_startup_entry(CPUHP_ONLINE);
 720 }
 721
 722 /* Check for early params. */
 723 static int __init do_early_param(char *param, char *val,
 724                                  const char *unused, void *arg)
 725 {
 726         const struct obs_kernel_param *p;
 727
 728         for (p = __setup_start; p < __setup_end; p++) {
 729                 if ((p->early && parameq(param, p->str)) ||
 730                     (strcmp(param, "console") == 0 &&
 731                      strcmp(p->str, "earlycon") == 0)
 732                 ) {
 733                         if (p->setup_func(val) != 0)
 734                                 pr_warn("Malformed early option '%s'\n", param);
 735                 }
 736         }
 737         /* We accept everything at this stage. */
 738         return 0;
 739 }
 740
 741 void __init parse_early_options(char *cmdline)
 742 {
 743         parse_args("early options", cmdline, NULL, 0, 0, 0, NULL,
 744                    do_early_param);
 745 }
 746
 747 /* Arch code calls this early on, or if not, just before other parsing. */
 748 void __init parse_early_param(void)
 749 {
 750         static int done __initdata;
 751         static char tmp_cmdline[COMMAND_LINE_SIZE] __initdata;
 752
 753         if (done)
 754                 return;
 755
 756         /* All fall through to do_early_param. */
 757         strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);
 758         parse_early_options(tmp_cmdline);
 759         done = 1;
 760 }
 761
 762 void __init __weak arch_post_acpi_subsys_init(void) { }
 763
 764 void __init __weak smp_setup_processor_id(void)
 765 {
 766 }
 767
 768 # if THREAD_SIZE >= PAGE_SIZE
 769 void __init __weak thread_stack_cache_init(void)
 770 {
 771 }
 772 #endif
 773
 774 void __init __weak mem_encrypt_init(void) { }
 775
 776 void __init __weak poking_init(void) { }
 777
 778 void __init __weak pgtable_cache_init(void) { }
 779
 780 bool initcall_debug;
 781 core_param(initcall_debug, initcall_debug, bool, 0644);
 782
 783 #ifdef TRACEPOINTS_ENABLED
 784 static void __init initcall_debug_enable(void);
 785 #else
 786 static inline void initcall_debug_enable(void)
 787 {
 788 }
 789 #endif
 790
 791 /* Report memory auto-initialization states for this boot. */
 792 static void __init report_meminit(void)
 793 {
 794         const char *stack;
 795
 796         if (IS_ENABLED(CONFIG_INIT_STACK_ALL_PATTERN))
 797                 stack = "all(pattern)";
 798         else if (IS_ENABLED(CONFIG_INIT_STACK_ALL_ZERO))
 799                 stack = "all(zero)";
 800         else if (IS_ENABLED(CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL))
 801                 stack = "byref_all(zero)";
 802         else if (IS_ENABLED(CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF))
 803                 stack = "byref(zero)";
 804         else if (IS_ENABLED(CONFIG_GCC_PLUGIN_STRUCTLEAK_USER))
 805                 stack = "__user(zero)";
 806         else
 807                 stack = "off";
 808
 809         pr_info("mem auto-init: stack:%s, heap alloc:%s, heap free:%s\n",
 810                 stack, want_init_on_alloc(GFP_KERNEL) ? "on" : "off",
 811                 want_init_on_free() ? "on" : "off");
 812         if (want_init_on_free())
 813                 pr_info("mem auto-init: clearing system memory may take some time...\n");
 814 }
 815
 816 /*
 817  * Set up kernel memory allocators
 818  */
 819 static void __init mm_init(void)
 820 {
 821         /*
 822          * page_ext requires contiguous pages,
 823          * bigger than MAX_ORDER unless SPARSEMEM.
 824          */
 825         page_ext_init_flatmem();
 826         init_mem_debugging_and_hardening();
 827         report_meminit();
 828         mem_init();
 829         /* page_owner must be initialized after buddy is ready */
 830         page_ext_init_flatmem_late();
 831         kmem_cache_init();
 832         kmemleak_init();
 833         pgtable_init();
 834         debug_objects_mem_init();
 835         vmalloc_init();
 836         ioremap_huge_init();
 837         /* Should be run before the first non-init thread is created */
 838         init_espfix_bsp();
 839         /* Should be run after espfix64 is set up. */
 840         pti_init();
 841 }
 842
 843 void __init __weak arch_call_rest_init(void)
 844 {
 845         rest_init();
 846 }
 847
 848 asmlinkage __visible void __init __no_sanitize_address start_kernel(void)
 849 {
 850         char *command_line;
 851         char *after_dashes;
 852
 853         set_task_stack_end_magic(&init_task);
 854         smp_setup_processor_id();
 855         debug_objects_early_init();
 856
 857         cgroup_init_early();
 858
 859         local_irq_disable();
 860         early_boot_irqs_disabled = true;
 861
 862         /*
 863          * Interrupts are still disabled. Do necessary setups, then
 864          * enable them.
 865          */
 866         boot_cpu_init();
 867         page_address_init();
 868         pr_notice("%s", linux_banner);
 869         early_security_init();
 870         setup_arch(&command_line);
 871         setup_boot_config(command_line);
 872         setup_command_line(command_line);
 873         setup_nr_cpu_ids();
 874         setup_per_cpu_areas();
 875         smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */
 876         boot_cpu_hotplug_init();
 877
 878         build_all_zonelists(NULL);
 879         page_alloc_init();
 880
 881         pr_notice("Kernel command line: %s\n", saved_command_line);
 882         /* parameters may set static keys */
 883         jump_label_init();
 884         parse_early_param();
 885         after_dashes = parse_args("Booting kernel",
 886                                   static_command_line, __start___param,
 887                                   __stop___param - __start___param,
 888                                   -1, -1, NULL, &unknown_bootoption);
 889         if (!IS_ERR_OR_NULL(after_dashes))
 890                 parse_args("Setting init args", after_dashes, NULL, 0, -1, -1,
 891                            NULL, set_init_arg);
 892         if (extra_init_args)
 893                 parse_args("Setting extra init args", extra_init_args,
 894                            NULL, 0, -1, -1, NULL, set_init_arg);
 895
 896         /*
 897          * These use large bootmem allocations and must precede
 898          * kmem_cache_init()
 899          */
 900         setup_log_buf(0);
 901         vfs_caches_init_early();
 902         sort_main_extable();
 903         trap_init();
 904         mm_init();
 905
 906         ftrace_init();
 907
 908         /* trace_printk can be enabled here */
 909         early_trace_init();
 910
 911         /*
 912          * Set up the scheduler prior starting any interrupts (such as the
 913          * timer interrupt). Full topology setup happens at smp_init()
 914          * time - but meanwhile we still have a functioning scheduler.
 915          */
 916         sched_init();
 917         /*
 918          * Disable preemption - early bootup scheduling is extremely
 919          * fragile until we cpu_idle() for the first time.
 920          */
 921         preempt_disable();
 922         if (WARN(!irqs_disabled(),
 923                  "Interrupts were enabled *very* early, fixing it\n"))
 924                 local_irq_disable();
 925         radix_tree_init();
 926
 927         /*
 928          * Set up housekeeping before setting up workqueues to allow the unbound
 929          * workqueue to take non-housekeeping into account.
 930          */
 931         housekeeping_init();
 932
 933         /*
 934          * Allow workqueue creation and work item queueing/cancelling
 935          * early.  Work item execution depends on kthreads and starts after
 936          * workqueue_init().
 937          */
 938         workqueue_init_early();
 939
 940         rcu_init();
 941
 942         /* Trace events are available after this */
 943         trace_init();
 944
 945         if (initcall_debug)
 946                 initcall_debug_enable();
 947
 948         context_tracking_init();
 949         /* init some links before init_ISA_irqs() */
 950         early_irq_init();
 951         init_IRQ();
 952         tick_init();
 953         rcu_init_nohz();
 954         init_timers();
 955         hrtimers_init();
 956         softirq_init();
 957         timekeeping_init();
 958
 959         /*
 960          * For best initial stack canary entropy, prepare it after:
 961          * - setup_arch() for any UEFI RNG entropy and boot cmdline access
 962          * - timekeeping_init() for ktime entropy used in rand_initialize()
 963          * - rand_initialize() to get any arch-specific entropy like RDRAND
 964          * - add_latent_entropy() to get any latent entropy
 965          * - adding command line entropy
 966          */
 967         rand_initialize();
 968         add_latent_entropy();
 969         add_device_randomness(command_line, strlen(command_line));
 970         boot_init_stack_canary();
 971
 972         time_init();
 973         perf_event_init();
 974         profile_init();
 975         call_function_init();
 976         WARN(!irqs_disabled(), "Interrupts were enabled early\n");
 977
 978         early_boot_irqs_disabled = false;
 979         local_irq_enable();
 980
 981         kmem_cache_init_late();
 982
 983         /*
 984          * HACK ALERT! This is early. We're enabling the console before
 985          * we've done PCI setups etc, and console_init() must be aware of
 986          * this. But we do want output early, in case something goes wrong.
 987          */
 988         console_init();
 989         if (panic_later)
 990                 panic("Too many boot %s vars at `%s'", panic_later,
 991                       panic_param);
 992
 993         lockdep_init();
 994
 995         /*
 996          * Need to run this when irqs are enabled, because it wants
 997          * to self-test [hard/soft]-irqs on/off lock inversion bugs
 998          * too:
 999          */
1000         locking_selftest();
1001
1002         /*
1003          * This needs to be called before any devices perform DMA
1004          * operations that might use the SWIOTLB bounce buffers. It will
1005          * mark the bounce buffers as decrypted so that their usage will
1006          * not cause "plain-text" data to be decrypted when accessed.
1007          */
1008         mem_encrypt_init();
1009
1010 #ifdef CONFIG_BLK_DEV_INITRD
1011         if (initrd_start && !initrd_below_start_ok &&
1012             page_to_pfn(virt_to_page((void *)initrd_start)) < min_low_pfn) {
1013                 pr_crit("initrd overwritten (0x%08lx < 0x%08lx) - disabling it.\n",
1014                     page_to_pfn(virt_to_page((void *)initrd_start)),
1015                     min_low_pfn);
1016                 initrd_start = 0;
1017         }
1018 #endif
1019         setup_per_cpu_pageset();
1020         numa_policy_init();
1021         acpi_early_init();
1022         if (late_time_init)
1023                 late_time_init();
1024         sched_clock_init();
1025         calibrate_delay();
1026         pid_idr_init();
1027         anon_vma_init();
1028 #ifdef CONFIG_X86
1029         if (efi_enabled(EFI_RUNTIME_SERVICES))
1030                 efi_enter_virtual_mode();
1031 #endif
1032         thread_stack_cache_init();
1033         cred_init();
1034         fork_init();
1035         proc_caches_init();
1036         uts_ns_init();
1037         key_init();
1038         security_init();
1039         dbg_late_init();
1040         vfs_caches_init();
1041         pagecache_init();
1042         signals_init();
1043         seq_file_init();
1044         proc_root_init();
1045         nsfs_init();
1046         cpuset_init();
1047         cgroup_init();
1048         taskstats_init_early();
1049         delayacct_init();
1050
1051         poking_init();
1052         check_bugs();
1053
1054         acpi_subsystem_init();
1055         arch_post_acpi_subsys_init();
1056         kcsan_init();
1057
1058         /* Do the rest non-__init'ed, we're now alive */
1059         arch_call_rest_init();
1060
1061         prevent_tail_call_optimization();
1062 }
1063
1064 /* Call all constructor functions linked into the kernel. */
1065 static void __init do_ctors(void)
1066 {
1067 /*
1068  * For UML, the constructors have already been called by the
1069  * normal setup code as it's just a normal ELF binary, so we
1070  * cannot do it again - but we do need CONFIG_CONSTRUCTORS
1071  * even on UML for modules.
1072  */
1073 #if defined(CONFIG_CONSTRUCTORS) && !defined(CONFIG_UML)
1074         ctor_fn_t *fn = (ctor_fn_t *) __ctors_start;
1075
1076         for (; fn < (ctor_fn_t *) __ctors_end; fn++)
1077                 (*fn)();
1078 #endif
1079 }
1080
1081 #ifdef CONFIG_KALLSYMS
1082 struct blacklist_entry {
1083         struct list_head next;
1084         char *buf;
1085 };
1086
1087 static __initdata_or_module LIST_HEAD(blacklisted_initcalls);
1088
1089 static int __init initcall_blacklist(char *str)
1090 {
1091         char *str_entry;
1092         struct blacklist_entry *entry;
1093
1094         /* str argument is a comma-separated list of functions */
1095         do {
1096                 str_entry = strsep(&str, ",");
1097                 if (str_entry) {
1098                         pr_debug("blacklisting initcall %s\n", str_entry);
1099                         entry = memblock_alloc(sizeof(*entry),
1100                                                SMP_CACHE_BYTES);
1101                         if (!entry)
1102                                 panic("%s: Failed to allocate %zu bytes\n",
1103                                       __func__, sizeof(*entry));
1104                         entry->buf = memblock_alloc(strlen(str_entry) + 1,
1105                                                     SMP_CACHE_BYTES);
1106                         if (!entry->buf)
1107                                 panic("%s: Failed to allocate %zu bytes\n",
1108                                       __func__, strlen(str_entry) + 1);
1109                         strcpy(entry->buf, str_entry);
1110                         list_add(&entry->next, &blacklisted_initcalls);
1111                 }
1112         } while (str_entry);
1113
1114         return 0;
1115 }
1116
1117 static bool __init_or_module initcall_blacklisted(initcall_t fn)
1118 {
1119         struct blacklist_entry *entry;
1120         char fn_name[KSYM_SYMBOL_LEN];
1121         unsigned long addr;
1122
1123         if (list_empty(&blacklisted_initcalls))
1124                 return false;
1125
1126         addr = (unsigned long) dereference_function_descriptor(fn);
1127         sprint_symbol_no_offset(fn_name, addr);
1128
1129         /*
1130          * fn will be "function_name [module_name]" where [module_name] is not
1131          * displayed for built-in init functions.  Strip off the [module_name].
1132          */
1133         strreplace(fn_name, ' ', '\0');
1134
1135         list_for_each_entry(entry, &blacklisted_initcalls, next) {
1136                 if (!strcmp(fn_name, entry->buf)) {
1137                         pr_debug("initcall %s blacklisted\n", fn_name);
1138                         return true;
1139                 }
1140         }
1141
1142         return false;
1143 }
1144 #else
1145 static int __init initcall_blacklist(char *str)
1146 {
1147         pr_warn("initcall_blacklist requires CONFIG_KALLSYMS\n");
1148         return 0;
1149 }
1150
1151 static bool __init_or_module initcall_blacklisted(initcall_t fn)
1152 {
1153         return false;
1154 }
1155 #endif
1156 __setup("initcall_blacklist=", initcall_blacklist);
1157
1158 static __init_or_module void
1159 trace_initcall_start_cb(void *data, initcall_t fn)
1160 {
1161         ktime_t *calltime = (ktime_t *)data;
1162
1163         printk(KERN_DEBUG "calling  %pS @ %i\n", fn, task_pid_nr(current));
1164         *calltime = ktime_get();
1165 }
1166
1167 static __init_or_module void
1168 trace_initcall_finish_cb(void *data, initcall_t fn, int ret)
1169 {
1170         ktime_t *calltime = (ktime_t *)data;
1171         ktime_t delta, rettime;
1172         unsigned long long duration;
1173
1174         rettime = ktime_get();
1175         delta = ktime_sub(rettime, *calltime);
1176         duration = (unsigned long long) ktime_to_ns(delta) >> 10;
1177         printk(KERN_DEBUG "initcall %pS returned %d after %lld usecs\n",
1178                  fn, ret, duration);
1179 }
1180
1181 static ktime_t initcall_calltime;
1182
1183 #ifdef TRACEPOINTS_ENABLED
1184 static void __init initcall_debug_enable(void)
1185 {
1186         int ret;
1187
1188         ret = register_trace_initcall_start(trace_initcall_start_cb,
1189                                             &initcall_calltime);
1190         ret |= register_trace_initcall_finish(trace_initcall_finish_cb,
1191                                               &initcall_calltime);
1192         WARN(ret, "Failed to register initcall tracepoints\n");
1193 }
1194 # define do_trace_initcall_start        trace_initcall_start
1195 # define do_trace_initcall_finish       trace_initcall_finish
1196 #else
1197 static inline void do_trace_initcall_start(initcall_t fn)
1198 {
1199         if (!initcall_debug)
1200                 return;
1201         trace_initcall_start_cb(&initcall_calltime, fn);
1202 }
1203 static inline void do_trace_initcall_finish(initcall_t fn, int ret)
1204 {
1205         if (!initcall_debug)
1206                 return;
1207         trace_initcall_finish_cb(&initcall_calltime, fn, ret);
1208 }
1209 #endif /* !TRACEPOINTS_ENABLED */
1210
1211 int __init_or_module do_one_initcall(initcall_t fn)
1212 {
1213         int count = preempt_count();
1214         char msgbuf[64];
1215         int ret;
1216
1217         if (initcall_blacklisted(fn))
1218                 return -EPERM;
1219
1220         do_trace_initcall_start(fn);
1221         ret = fn();
1222         do_trace_initcall_finish(fn, ret);
1223
1224         msgbuf[0] = 0;
1225
1226         if (preempt_count() != count) {
1227                 sprintf(msgbuf, "preemption imbalance ");
1228                 preempt_count_set(count);
1229         }
1230         if (irqs_disabled()) {
1231                 strlcat(msgbuf, "disabled interrupts ", sizeof(msgbuf));
1232                 local_irq_enable();
1233         }
1234         WARN(msgbuf[0], "initcall %pS returned with %s\n", fn, msgbuf);
1235
1236         add_latent_entropy();
1237         return ret;
1238 }
1239
1240
1241 extern initcall_entry_t __initcall_start[];
1242 extern initcall_entry_t __initcall0_start[];
1243 extern initcall_entry_t __initcall1_start[];
1244 extern initcall_entry_t __initcall2_start[];
1245 extern initcall_entry_t __initcall3_start[];
1246 extern initcall_entry_t __initcall4_start[];
1247 extern initcall_entry_t __initcall5_start[];
1248 extern initcall_entry_t __initcall6_start[];
1249 extern initcall_entry_t __initcall7_start[];
1250 extern initcall_entry_t __initcall_end[];
1251
1252 static initcall_entry_t *initcall_levels[] __initdata = {
1253         __initcall0_start,
1254         __initcall1_start,
1255         __initcall2_start,
1256         __initcall3_start,
1257         __initcall4_start,
1258         __initcall5_start,
1259         __initcall6_start,
1260         __initcall7_start,
1261         __initcall_end,
1262 };
1263
1264 /* Keep these in sync with initcalls in include/linux/init.h */
1265 static const char *initcall_level_names[] __initdata = {
1266         "pure",
1267         "core",
1268         "postcore",
1269         "arch",
1270         "subsys",
1271         "fs",
1272         "device",
1273         "late",
1274 };
1275
1276 static int __init ignore_unknown_bootoption(char *param, char *val,
1277                                const char *unused, void *arg)
1278 {
1279         return 0;
1280 }
1281
1282 static void __init do_initcall_level(int level, char *command_line)
1283 {
1284         initcall_entry_t *fn;
1285
1286         parse_args(initcall_level_names[level],
1287                    command_line, __start___param,
1288                    __stop___param - __start___param,
1289                    level, level,
1290                    NULL, ignore_unknown_bootoption);
1291
1292         trace_initcall_level(initcall_level_names[level]);
1293         for (fn = initcall_levels[level]; fn < initcall_levels[level+1]; fn++)
1294                 do_one_initcall(initcall_from_entry(fn));
1295 }
1296
1297 static void __init do_initcalls(void)
1298 {
1299         int level;
1300         size_t len = strlen(saved_command_line) + 1;
1301         char *command_line;
1302
1303         command_line = kzalloc(len, GFP_KERNEL);
1304         if (!command_line)
1305                 panic("%s: Failed to allocate %zu bytes\n", __func__, len);
1306
1307         for (level = 0; level < ARRAY_SIZE(initcall_levels) - 1; level++) {
1308                 /* Parser modifies command_line, restore it each time */
1309                 strcpy(command_line, saved_command_line);
1310                 do_initcall_level(level, command_line);
1311         }
1312
1313         kfree(command_line);
1314 }
1315
1316 /*
1317  * Ok, the machine is now initialized. None of the devices
1318  * have been touched yet, but the CPU subsystem is up and
1319  * running, and memory and process management works.
1320  *
1321  * Now we can finally start doing some real work..
1322  */
1323 static void __init do_basic_setup(void)
1324 {
1325         cpuset_init_smp();
1326         driver_init();
1327         init_irq_proc();
1328         do_ctors();
1329         usermodehelper_enable();
1330         do_initcalls();
1331 }
1332
1333 static void __init do_pre_smp_initcalls(void)
1334 {
1335         initcall_entry_t *fn;
1336
1337         trace_initcall_level("early");
1338         for (fn = __initcall_start; fn < __initcall0_start; fn++)
1339                 do_one_initcall(initcall_from_entry(fn));
1340 }
1341
1342 static int run_init_process(const char *init_filename)
1343 {
1344         const char *const *p;
1345
1346         argv_init[0] = init_filename;
1347         pr_info("Run %s as init process\n", init_filename);
1348         pr_debug("  with arguments:\n");
1349         for (p = argv_init; *p; p++)
1350                 pr_debug("    %s\n", *p);
1351         pr_debug("  with environment:\n");
1352         for (p = envp_init; *p; p++)
1353                 pr_debug("    %s\n", *p);
1354         return kernel_execve(init_filename, argv_init, envp_init);
1355 }
1356
1357 static int try_to_run_init_process(const char *init_filename)
1358 {
1359         int ret;
1360
1361         ret = run_init_process(init_filename);
1362
1363         if (ret && ret != -ENOENT) {
1364                 pr_err("Starting init: %s exists but couldn't execute it (error %d)\n",
1365                        init_filename, ret);
1366         }
1367
1368         return ret;
1369 }
1370
1371 static noinline void __init kernel_init_freeable(void);
1372
1373 #if defined(CONFIG_STRICT_KERNEL_RWX) || defined(CONFIG_STRICT_MODULE_RWX)
1374 bool rodata_enabled __ro_after_init = true;
1375 static int __init set_debug_rodata(char *str)
1376 {
1377         return strtobool(str, &rodata_enabled);
1378 }
1379 __setup("rodata=", set_debug_rodata);
1380 #endif
1381
1382 #ifdef CONFIG_STRICT_KERNEL_RWX
1383 static void mark_readonly(void)
1384 {
1385         if (rodata_enabled) {
1386                 /*
1387                  * load_module() results in W+X mappings, which are cleaned
1388                  * up with call_rcu().  Let's make sure that queued work is
1389                  * flushed so that we don't hit false positives looking for
1390                  * insecure pages which are W+X.
1391                  */
1392                 rcu_barrier();
1393                 mark_rodata_ro();
1394                 rodata_test();
1395         } else
1396                 pr_info("Kernel memory protection disabled.\n");
1397 }
1398 #elif defined(CONFIG_ARCH_HAS_STRICT_KERNEL_RWX)
1399 static inline void mark_readonly(void)
1400 {
1401         pr_warn("Kernel memory protection not selected by kernel config.\n");
1402 }
1403 #else
1404 static inline void mark_readonly(void)
1405 {
1406         pr_warn("This architecture does not have kernel memory protection.\n");
1407 }
1408 #endif
1409
1410 void __weak free_initmem(void)
1411 {
1412         free_initmem_default(POISON_FREE_INITMEM);
1413 }
1414
1415 static int __ref kernel_init(void *unused)
1416 {
1417         int ret;
1418
1419         kernel_init_freeable();
1420         /* need to finish all async __init code before freeing the memory */
1421         async_synchronize_full();
1422         kprobe_free_init_mem();
1423         ftrace_free_init_mem();
1424         free_initmem();
1425         mark_readonly();
1426
1427         /*
1428          * Kernel mappings are now finalized - update the userspace page-table
1429          * to finalize PTI.
1430          */
1431         pti_finalize();
1432
1433         system_state = SYSTEM_RUNNING;
1434         numa_default_policy();
1435
1436         rcu_end_inkernel_boot();
1437
1438         do_sysctl_args();
1439
1440         if (ramdisk_execute_command) {
1441                 ret = run_init_process(ramdisk_execute_command);
1442                 if (!ret)
1443                         return 0;
1444                 pr_err("Failed to execute %s (error %d)\n",
1445                        ramdisk_execute_command, ret);
1446         }
1447
1448         /*
1449          * We try each of these until one succeeds.
1450          *
1451          * The Bourne shell can be used instead of init if we are
1452          * trying to recover a really broken machine.
1453          */
1454         if (execute_command) {
1455                 ret = run_init_process(execute_command);
1456                 if (!ret)
1457                         return 0;
1458                 panic("Requested init %s failed (error %d).",
1459                       execute_command, ret);
1460         }
1461
1462         if (CONFIG_DEFAULT_INIT[0] != '\0') {
1463                 ret = run_init_process(CONFIG_DEFAULT_INIT);
1464                 if (ret)
1465                         pr_err("Default init %s failed (error %d)\n",
1466                                CONFIG_DEFAULT_INIT, ret);
1467                 else
1468                         return 0;
1469         }
1470
1471         if (!try_to_run_init_process("/sbin/init") ||
1472             !try_to_run_init_process("/etc/init") ||
1473             !try_to_run_init_process("/bin/init") ||
1474             !try_to_run_init_process("/bin/sh"))
1475                 return 0;
1476
1477         panic("No working init found.  Try passing init= option to kernel. "
1478               "See Linux Documentation/admin-guide/init.rst for guidance.");
1479 }
1480
1481 /* Open /dev/console, for stdin/stdout/stderr, this should never fail */
1482 void __init console_on_rootfs(void)
1483 {
1484         struct file *file = filp_open("/dev/console", O_RDWR, 0);
1485
1486         if (IS_ERR(file)) {
1487                 pr_err("Warning: unable to open an initial console.\n");
1488                 return;
1489         }
1490         init_dup(file);
1491         init_dup(file);
1492         init_dup(file);
1493         fput(file);
1494 }
1495
1496 static noinline void __init kernel_init_freeable(void)
1497 {
1498         /*
1499          * Wait until kthreadd is all set-up.
1500          */
1501         wait_for_completion(&kthreadd_done);
1502
1503         /* Now the scheduler is fully set up and can do blocking allocations */
1504         gfp_allowed_mask = __GFP_BITS_MASK;
1505
1506         /*
1507          * init can allocate pages on any node
1508          */
1509         set_mems_allowed(node_states[N_MEMORY]);
1510
1511         cad_pid = task_pid(current);
1512
1513         smp_prepare_cpus(setup_max_cpus);
1514
1515         workqueue_init();
1516
1517         init_mm_internals();
1518
1519         rcu_init_tasks_generic();
1520         do_pre_smp_initcalls();
1521         lockup_detector_init();
1522
1523         smp_init();
1524         sched_init_smp();
1525
1526         padata_init();
1527         page_alloc_init_late();
1528         /* Initialize page ext after all struct pages are initialized. */
1529         page_ext_init();
1530
1531         do_basic_setup();
1532
1533         kunit_run_all_tests();
1534
1535         console_on_rootfs();
1536
1537         /*
1538          * check if there is an early userspace init.  If yes, let it do all
1539          * the work
1540          */
1541         if (init_eaccess(ramdisk_execute_command) != 0) {
1542                 ramdisk_execute_command = NULL;
1543                 prepare_namespace();
1544         }
1545
1546         /*
1547          * Ok, we have completed the initial bootup, and
1548          * we're essentially up and running. Get rid of the
1549          * initmem segments and start the user-mode stuff..
1550          *
1551          * rootfs is available now, try loading the public keys
1552          * and default modules
1553          */
1554
1555         integrity_load_keys();
1556 }