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/kmsan.h>
  38 #include <linux/vmalloc.h>
  39 #include <linux/kernel_stat.h>
  40 #include <linux/start_kernel.h>
  41 #include <linux/security.h>
  42 #include <linux/smp.h>
  43 #include <linux/profile.h>
  44 #include <linux/kfence.h>
  45 #include <linux/rcupdate.h>
  46 #include <linux/srcu.h>
  47 #include <linux/moduleparam.h>
  48 #include <linux/kallsyms.h>
  49 #include <linux/buildid.h>
  50 #include <linux/writeback.h>
  51 #include <linux/cpu.h>
  52 #include <linux/cpuset.h>
  53 #include <linux/cgroup.h>
  54 #include <linux/efi.h>
  55 #include <linux/tick.h>
  56 #include <linux/sched/isolation.h>
  57 #include <linux/interrupt.h>
  58 #include <linux/taskstats_kern.h>
  59 #include <linux/delayacct.h>
  60 #include <linux/unistd.h>
  61 #include <linux/utsname.h>
  62 #include <linux/rmap.h>
  63 #include <linux/mempolicy.h>
  64 #include <linux/key.h>
  65 #include <linux/debug_locks.h>
  66 #include <linux/debugobjects.h>
  67 #include <linux/lockdep.h>
  68 #include <linux/kmemleak.h>
  69 #include <linux/padata.h>
  70 #include <linux/pid_namespace.h>
  71 #include <linux/device/driver.h>
  72 #include <linux/kthread.h>
  73 #include <linux/sched.h>
  74 #include <linux/sched/init.h>
  75 #include <linux/signal.h>
  76 #include <linux/idr.h>
  77 #include <linux/kgdb.h>
  78 #include <linux/ftrace.h>
  79 #include <linux/async.h>
  80 #include <linux/shmem_fs.h>
  81 #include <linux/slab.h>
  82 #include <linux/perf_event.h>
  83 #include <linux/ptrace.h>
  84 #include <linux/pti.h>
  85 #include <linux/blkdev.h>
  86 #include <linux/sched/clock.h>
  87 #include <linux/sched/task.h>
  88 #include <linux/sched/task_stack.h>
  89 #include <linux/context_tracking.h>
  90 #include <linux/random.h>
  91 #include <linux/moduleloader.h>
  92 #include <linux/list.h>
  93 #include <linux/integrity.h>
  94 #include <linux/proc_ns.h>
  95 #include <linux/io.h>
  96 #include <linux/cache.h>
  97 #include <linux/rodata_test.h>
  98 #include <linux/jump_label.h>
  99 #include <linux/kcsan.h>
 100 #include <linux/init_syscalls.h>
 101 #include <linux/stackdepot.h>
 102 #include <linux/randomize_kstack.h>
 103 #include <linux/pidfs.h>
 104 #include <linux/ptdump.h>
 105 #include <net/net_namespace.h>
 106
 107 #include <asm/io.h>
 108 #include <asm/setup.h>
 109 #include <asm/sections.h>
 110 #include <asm/cacheflush.h>
 111
 112 #define CREATE_TRACE_POINTS
 113 #include <trace/events/initcall.h>
 114
 115 #include <kunit/test.h>
 116
 117 static int kernel_init(void *);
 118
 119 /*
 120  * Debug helper: via this flag we know that we are in 'early bootup code'
 121  * where only the boot processor is running with IRQ disabled.  This means
 122  * two things - IRQ must not be enabled before the flag is cleared and some
 123  * operations which are not allowed with IRQ disabled are allowed while the
 124  * flag is set.
 125  */
 126 bool early_boot_irqs_disabled __read_mostly;
 127
 128 enum system_states system_state __read_mostly;
 129 EXPORT_SYMBOL(system_state);
 130
 131 /*
 132  * Boot command-line arguments
 133  */
 134 #define MAX_INIT_ARGS CONFIG_INIT_ENV_ARG_LIMIT
 135 #define MAX_INIT_ENVS CONFIG_INIT_ENV_ARG_LIMIT
 136
 137 /* Default late time init is NULL. archs can override this later. */
 138 void (*__initdata late_time_init)(void);
 139
 140 /* Untouched command line saved by arch-specific code. */
 141 char __initdata boot_command_line[COMMAND_LINE_SIZE];
 142 /* Untouched saved command line (eg. for /proc) */
 143 char *saved_command_line __ro_after_init;
 144 unsigned int saved_command_line_len __ro_after_init;
 145 /* Command line for parameter parsing */
 146 static char *static_command_line;
 147 /* Untouched extra command line */
 148 static char *extra_command_line;
 149 /* Extra init arguments */
 150 static char *extra_init_args;
 151
 152 #ifdef CONFIG_BOOT_CONFIG
 153 /* Is bootconfig on command line? */
 154 static bool bootconfig_found;
 155 static size_t initargs_offs;
 156 #else
 157 # define bootconfig_found false
 158 # define initargs_offs 0
 159 #endif
 160
 161 static char *execute_command;
 162 static char *ramdisk_execute_command = "/init";
 163
 164 /*
 165  * Used to generate warnings if static_key manipulation functions are used
 166  * before jump_label_init is called.
 167  */
 168 bool static_key_initialized __read_mostly;
 169 EXPORT_SYMBOL_GPL(static_key_initialized);
 170
 171 /*
 172  * If set, this is an indication to the drivers that reset the underlying
 173  * device before going ahead with the initialization otherwise driver might
 174  * rely on the BIOS and skip the reset operation.
 175  *
 176  * This is useful if kernel is booting in an unreliable environment.
 177  * For ex. kdump situation where previous kernel has crashed, BIOS has been
 178  * skipped and devices will be in unknown state.
 179  */
 180 unsigned int reset_devices;
 181 EXPORT_SYMBOL(reset_devices);
 182
 183 static int __init set_reset_devices(char *str)
 184 {
 185         reset_devices = 1;
 186         return 1;
 187 }
 188
 189 __setup("reset_devices", set_reset_devices);
 190
 191 static const char *argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
 192 const char *envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, };
 193 static const char *panic_later, *panic_param;
 194
 195 static bool __init obsolete_checksetup(char *line)
 196 {
 197         const struct obs_kernel_param *p;
 198         bool had_early_param = false;
 199
 200         p = __setup_start;
 201         do {
 202                 int n = strlen(p->str);
 203                 if (parameqn(line, p->str, n)) {
 204                         if (p->early) {
 205                                 /* Already done in parse_early_param?
 206                                  * (Needs exact match on param part).
 207                                  * Keep iterating, as we can have early
 208                                  * params and __setups of same names 8( */
 209                                 if (line[n] == '\0' || line[n] == '=')
 210                                         had_early_param = true;
 211                         } else if (!p->setup_func) {
 212                                 pr_warn("Parameter %s is obsolete, ignored\n",
 213                                         p->str);
 214                                 return true;
 215                         } else if (p->setup_func(line + n))
 216                                 return true;
 217                 }
 218                 p++;
 219         } while (p < __setup_end);
 220
 221         return had_early_param;
 222 }
 223
 224 /*
 225  * This should be approx 2 Bo*oMips to start (note initial shift), and will
 226  * still work even if initially too large, it will just take slightly longer
 227  */
 228 unsigned long loops_per_jiffy = (1<<12);
 229 EXPORT_SYMBOL(loops_per_jiffy);
 230
 231 static int __init debug_kernel(char *str)
 232 {
 233         console_loglevel = CONSOLE_LOGLEVEL_DEBUG;
 234         return 0;
 235 }
 236
 237 static int __init quiet_kernel(char *str)
 238 {
 239         console_loglevel = CONSOLE_LOGLEVEL_QUIET;
 240         return 0;
 241 }
 242
 243 early_param("debug", debug_kernel);
 244 early_param("quiet", quiet_kernel);
 245
 246 static int __init loglevel(char *str)
 247 {
 248         int newlevel;
 249
 250         /*
 251          * Only update loglevel value when a correct setting was passed,
 252          * to prevent blind crashes (when loglevel being set to 0) that
 253          * are quite hard to debug
 254          */
 255         if (get_option(&str, &newlevel)) {
 256                 console_loglevel = newlevel;
 257                 return 0;
 258         }
 259
 260         return -EINVAL;
 261 }
 262
 263 early_param("loglevel", loglevel);
 264
 265 #ifdef CONFIG_BLK_DEV_INITRD
 266 static void * __init get_boot_config_from_initrd(size_t *_size)
 267 {
 268         u32 size, csum;
 269         char *data;
 270         u32 *hdr;
 271         int i;
 272
 273         if (!initrd_end)
 274                 return NULL;
 275
 276         data = (char *)initrd_end - BOOTCONFIG_MAGIC_LEN;
 277         /*
 278          * Since Grub may align the size of initrd to 4, we must
 279          * check the preceding 3 bytes as well.
 280          */
 281         for (i = 0; i < 4; i++) {
 282                 if (!memcmp(data, BOOTCONFIG_MAGIC, BOOTCONFIG_MAGIC_LEN))
 283                         goto found;
 284                 data--;
 285         }
 286         return NULL;
 287
 288 found:
 289         hdr = (u32 *)(data - 8);
 290         size = le32_to_cpu(hdr[0]);
 291         csum = le32_to_cpu(hdr[1]);
 292
 293         data = ((void *)hdr) - size;
 294         if ((unsigned long)data < initrd_start) {
 295                 pr_err("bootconfig size %d is greater than initrd size %ld\n",
 296                         size, initrd_end - initrd_start);
 297                 return NULL;
 298         }
 299
 300         if (xbc_calc_checksum(data, size) != csum) {
 301                 pr_err("bootconfig checksum failed\n");
 302                 return NULL;
 303         }
 304
 305         /* Remove bootconfig from initramfs/initrd */
 306         initrd_end = (unsigned long)data;
 307         if (_size)
 308                 *_size = size;
 309
 310         return data;
 311 }
 312 #else
 313 static void * __init get_boot_config_from_initrd(size_t *_size)
 314 {
 315         return NULL;
 316 }
 317 #endif
 318
 319 #ifdef CONFIG_BOOT_CONFIG
 320
 321 static char xbc_namebuf[XBC_KEYLEN_MAX] __initdata;
 322
 323 #define rest(dst, end) ((end) > (dst) ? (end) - (dst) : 0)
 324
 325 static int __init xbc_snprint_cmdline(char *buf, size_t size,
 326                                       struct xbc_node *root)
 327 {
 328         struct xbc_node *knode, *vnode;
 329         char *end = buf + size;
 330         const char *val, *q;
 331         int ret;
 332
 333         xbc_node_for_each_key_value(root, knode, val) {
 334                 ret = xbc_node_compose_key_after(root, knode,
 335                                         xbc_namebuf, XBC_KEYLEN_MAX);
 336                 if (ret < 0)
 337                         return ret;
 338
 339                 vnode = xbc_node_get_child(knode);
 340                 if (!vnode) {
 341                         ret = snprintf(buf, rest(buf, end), "%s ", xbc_namebuf);
 342                         if (ret < 0)
 343                                 return ret;
 344                         buf += ret;
 345                         continue;
 346                 }
 347                 xbc_array_for_each_value(vnode, val) {
 348                         /*
 349                          * For prettier and more readable /proc/cmdline, only
 350                          * quote the value when necessary, i.e. when it contains
 351                          * whitespace.
 352                          */
 353                         q = strpbrk(val, " \t\r\n") ? "\"" : "";
 354                         ret = snprintf(buf, rest(buf, end), "%s=%s%s%s ",
 355                                        xbc_namebuf, q, val, q);
 356                         if (ret < 0)
 357                                 return ret;
 358                         buf += ret;
 359                 }
 360         }
 361
 362         return buf - (end - size);
 363 }
 364 #undef rest
 365
 366 /* Make an extra command line under given key word */
 367 static char * __init xbc_make_cmdline(const char *key)
 368 {
 369         struct xbc_node *root;
 370         char *new_cmdline;
 371         int ret, len = 0;
 372
 373         root = xbc_find_node(key);
 374         if (!root)
 375                 return NULL;
 376
 377         /* Count required buffer size */
 378         len = xbc_snprint_cmdline(NULL, 0, root);
 379         if (len <= 0)
 380                 return NULL;
 381
 382         new_cmdline = memblock_alloc(len + 1, SMP_CACHE_BYTES);
 383         if (!new_cmdline) {
 384                 pr_err("Failed to allocate memory for extra kernel cmdline.\n");
 385                 return NULL;
 386         }
 387
 388         ret = xbc_snprint_cmdline(new_cmdline, len + 1, root);
 389         if (ret < 0 || ret > len) {
 390                 pr_err("Failed to print extra kernel cmdline.\n");
 391                 memblock_free(new_cmdline, len + 1);
 392                 return NULL;
 393         }
 394
 395         return new_cmdline;
 396 }
 397
 398 static int __init bootconfig_params(char *param, char *val,
 399                                     const char *unused, void *arg)
 400 {
 401         if (strcmp(param, "bootconfig") == 0) {
 402                 bootconfig_found = true;
 403         }
 404         return 0;
 405 }
 406
 407 static int __init warn_bootconfig(char *str)
 408 {
 409         /* The 'bootconfig' has been handled by bootconfig_params(). */
 410         return 0;
 411 }
 412
 413 static void __init setup_boot_config(void)
 414 {
 415         static char tmp_cmdline[COMMAND_LINE_SIZE] __initdata;
 416         const char *msg, *data;
 417         int pos, ret;
 418         size_t size;
 419         char *err;
 420
 421         /* Cut out the bootconfig data even if we have no bootconfig option */
 422         data = get_boot_config_from_initrd(&size);
 423         /* If there is no bootconfig in initrd, try embedded one. */
 424         if (!data)
 425                 data = xbc_get_embedded_bootconfig(&size);
 426
 427         strscpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);
 428         err = parse_args("bootconfig", tmp_cmdline, NULL, 0, 0, 0, NULL,
 429                          bootconfig_params);
 430
 431         if (IS_ERR(err) || !(bootconfig_found || IS_ENABLED(CONFIG_BOOT_CONFIG_FORCE)))
 432                 return;
 433
 434         /* parse_args() stops at the next param of '--' and returns an address */
 435         if (err)
 436                 initargs_offs = err - tmp_cmdline;
 437
 438         if (!data) {
 439                 /* If user intended to use bootconfig, show an error level message */
 440                 if (bootconfig_found)
 441                         pr_err("'bootconfig' found on command line, but no bootconfig found\n");
 442                 else
 443                         pr_info("No bootconfig data provided, so skipping bootconfig");
 444                 return;
 445         }
 446
 447         if (size >= XBC_DATA_MAX) {
 448                 pr_err("bootconfig size %ld greater than max size %d\n",
 449                         (long)size, XBC_DATA_MAX);
 450                 return;
 451         }
 452
 453         ret = xbc_init(data, size, &msg, &pos);
 454         if (ret < 0) {
 455                 if (pos < 0)
 456                         pr_err("Failed to init bootconfig: %s.\n", msg);
 457                 else
 458                         pr_err("Failed to parse bootconfig: %s at %d.\n",
 459                                 msg, pos);
 460         } else {
 461                 xbc_get_info(&ret, NULL);
 462                 pr_info("Load bootconfig: %ld bytes %d nodes\n", (long)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 static void __init exit_boot_config(void)
 472 {
 473         xbc_exit();
 474 }
 475
 476 #else   /* !CONFIG_BOOT_CONFIG */
 477
 478 static void __init setup_boot_config(void)
 479 {
 480         /* Remove bootconfig data from initrd */
 481         get_boot_config_from_initrd(NULL);
 482 }
 483
 484 static int __init warn_bootconfig(char *str)
 485 {
 486         pr_warn("WARNING: 'bootconfig' found on the kernel command line but CONFIG_BOOT_CONFIG is not set.\n");
 487         return 0;
 488 }
 489
 490 #define exit_boot_config()      do {} while (0)
 491
 492 #endif  /* CONFIG_BOOT_CONFIG */
 493
 494 early_param("bootconfig", warn_bootconfig);
 495
 496 bool __init cmdline_has_extra_options(void)
 497 {
 498         return extra_command_line || extra_init_args;
 499 }
 500
 501 /* Change NUL term back to "=", to make "param" the whole string. */
 502 static void __init repair_env_string(char *param, char *val)
 503 {
 504         if (val) {
 505                 /* param=val or param="val"? */
 506                 if (val == param+strlen(param)+1)
 507                         val[-1] = '=';
 508                 else if (val == param+strlen(param)+2) {
 509                         val[-2] = '=';
 510                         memmove(val-1, val, strlen(val)+1);
 511                 } else
 512                         BUG();
 513         }
 514 }
 515
 516 /* Anything after -- gets handed straight to init. */
 517 static int __init set_init_arg(char *param, char *val,
 518                                const char *unused, void *arg)
 519 {
 520         unsigned int i;
 521
 522         if (panic_later)
 523                 return 0;
 524
 525         repair_env_string(param, val);
 526
 527         for (i = 0; argv_init[i]; i++) {
 528                 if (i == MAX_INIT_ARGS) {
 529                         panic_later = "init";
 530                         panic_param = param;
 531                         return 0;
 532                 }
 533         }
 534         argv_init[i] = param;
 535         return 0;
 536 }
 537
 538 /*
 539  * Unknown boot options get handed to init, unless they look like
 540  * unused parameters (modprobe will find them in /proc/cmdline).
 541  */
 542 static int __init unknown_bootoption(char *param, char *val,
 543                                      const char *unused, void *arg)
 544 {
 545         size_t len = strlen(param);
 546
 547         /* Handle params aliased to sysctls */
 548         if (sysctl_is_alias(param))
 549                 return 0;
 550
 551         repair_env_string(param, val);
 552
 553         /* Handle obsolete-style parameters */
 554         if (obsolete_checksetup(param))
 555                 return 0;
 556
 557         /* Unused module parameter. */
 558         if (strnchr(param, len, '.'))
 559                 return 0;
 560
 561         if (panic_later)
 562                 return 0;
 563
 564         if (val) {
 565                 /* Environment option */
 566                 unsigned int i;
 567                 for (i = 0; envp_init[i]; i++) {
 568                         if (i == MAX_INIT_ENVS) {
 569                                 panic_later = "env";
 570                                 panic_param = param;
 571                         }
 572                         if (!strncmp(param, envp_init[i], len+1))
 573                                 break;
 574                 }
 575                 envp_init[i] = param;
 576         } else {
 577                 /* Command line option */
 578                 unsigned int i;
 579                 for (i = 0; argv_init[i]; i++) {
 580                         if (i == MAX_INIT_ARGS) {
 581                                 panic_later = "init";
 582                                 panic_param = param;
 583                         }
 584                 }
 585                 argv_init[i] = param;
 586         }
 587         return 0;
 588 }
 589
 590 static int __init init_setup(char *str)
 591 {
 592         unsigned int i;
 593
 594         execute_command = str;
 595         /*
 596          * In case LILO is going to boot us with default command line,
 597          * it prepends "auto" before the whole cmdline which makes
 598          * the shell think it should execute a script with such name.
 599          * So we ignore all arguments entered _before_ init=... [MJ]
 600          */
 601         for (i = 1; i < MAX_INIT_ARGS; i++)
 602                 argv_init[i] = NULL;
 603         return 1;
 604 }
 605 __setup("init=", init_setup);
 606
 607 static int __init rdinit_setup(char *str)
 608 {
 609         unsigned int i;
 610
 611         ramdisk_execute_command = str;
 612         /* See "auto" comment in init_setup */
 613         for (i = 1; i < MAX_INIT_ARGS; i++)
 614                 argv_init[i] = NULL;
 615         return 1;
 616 }
 617 __setup("rdinit=", rdinit_setup);
 618
 619 #ifndef CONFIG_SMP
 620 static inline void setup_nr_cpu_ids(void) { }
 621 static inline void smp_prepare_cpus(unsigned int maxcpus) { }
 622 #endif
 623
 624 /*
 625  * We need to store the untouched command line for future reference.
 626  * We also need to store the touched command line since the parameter
 627  * parsing is performed in place, and we should allow a component to
 628  * store reference of name/value for future reference.
 629  */
 630 static void __init setup_command_line(char *command_line)
 631 {
 632         size_t len, xlen = 0, ilen = 0;
 633
 634         if (extra_command_line)
 635                 xlen = strlen(extra_command_line);
 636         if (extra_init_args) {
 637                 extra_init_args = strim(extra_init_args); /* remove trailing space */
 638                 ilen = strlen(extra_init_args) + 4; /* for " -- " */
 639         }
 640
 641         len = xlen + strlen(boot_command_line) + ilen + 1;
 642
 643         saved_command_line = memblock_alloc(len, SMP_CACHE_BYTES);
 644         if (!saved_command_line)
 645                 panic("%s: Failed to allocate %zu bytes\n", __func__, len);
 646
 647         len = xlen + strlen(command_line) + 1;
 648
 649         static_command_line = memblock_alloc(len, SMP_CACHE_BYTES);
 650         if (!static_command_line)
 651                 panic("%s: Failed to allocate %zu bytes\n", __func__, len);
 652
 653         if (xlen) {
 654                 /*
 655                  * We have to put extra_command_line before boot command
 656                  * lines because there could be dashes (separator of init
 657                  * command line) in the command lines.
 658                  */
 659                 strcpy(saved_command_line, extra_command_line);
 660                 strcpy(static_command_line, extra_command_line);
 661         }
 662         strcpy(saved_command_line + xlen, boot_command_line);
 663         strcpy(static_command_line + xlen, command_line);
 664
 665         if (ilen) {
 666                 /*
 667                  * Append supplemental init boot args to saved_command_line
 668                  * so that user can check what command line options passed
 669                  * to init.
 670                  * The order should always be
 671                  * " -- "[bootconfig init-param][cmdline init-param]
 672                  */
 673                 if (initargs_offs) {
 674                         len = xlen + initargs_offs;
 675                         strcpy(saved_command_line + len, extra_init_args);
 676                         len += ilen - 4;        /* strlen(extra_init_args) */
 677                         strcpy(saved_command_line + len,
 678                                 boot_command_line + initargs_offs - 1);
 679                 } else {
 680                         len = strlen(saved_command_line);
 681                         strcpy(saved_command_line + len, " -- ");
 682                         len += 4;
 683                         strcpy(saved_command_line + len, extra_init_args);
 684                 }
 685         }
 686
 687         saved_command_line_len = strlen(saved_command_line);
 688 }
 689
 690 /*
 691  * We need to finalize in a non-__init function or else race conditions
 692  * between the root thread and the init thread may cause start_kernel to
 693  * be reaped by free_initmem before the root thread has proceeded to
 694  * cpu_idle.
 695  *
 696  * gcc-3.4 accidentally inlines this function, so use noinline.
 697  */
 698
 699 static __initdata DECLARE_COMPLETION(kthreadd_done);
 700
 701 static noinline void __ref __noreturn rest_init(void)
 702 {
 703         struct task_struct *tsk;
 704         int pid;
 705
 706         rcu_scheduler_starting();
 707         /*
 708          * We need to spawn init first so that it obtains pid 1, however
 709          * the init task will end up wanting to create kthreads, which, if
 710          * we schedule it before we create kthreadd, will OOPS.
 711          */
 712         pid = user_mode_thread(kernel_init, NULL, CLONE_FS);
 713         /*
 714          * Pin init on the boot CPU. Task migration is not properly working
 715          * until sched_init_smp() has been run. It will set the allowed
 716          * CPUs for init to the non isolated CPUs.
 717          */
 718         rcu_read_lock();
 719         tsk = find_task_by_pid_ns(pid, &init_pid_ns);
 720         tsk->flags |= PF_NO_SETAFFINITY;
 721         set_cpus_allowed_ptr(tsk, cpumask_of(smp_processor_id()));
 722         rcu_read_unlock();
 723
 724         numa_default_policy();
 725         pid = kernel_thread(kthreadd, NULL, NULL, CLONE_FS | CLONE_FILES);
 726         rcu_read_lock();
 727         kthreadd_task = find_task_by_pid_ns(pid, &init_pid_ns);
 728         rcu_read_unlock();
 729
 730         /*
 731          * Enable might_sleep() and smp_processor_id() checks.
 732          * They cannot be enabled earlier because with CONFIG_PREEMPTION=y
 733          * kernel_thread() would trigger might_sleep() splats. With
 734          * CONFIG_PREEMPT_VOLUNTARY=y the init task might have scheduled
 735          * already, but it's stuck on the kthreadd_done completion.
 736          */
 737         system_state = SYSTEM_SCHEDULING;
 738
 739         complete(&kthreadd_done);
 740
 741         /*
 742          * The boot idle thread must execute schedule()
 743          * at least once to get things moving:
 744          */
 745         schedule_preempt_disabled();
 746         /* Call into cpu_idle with preempt disabled */
 747         cpu_startup_entry(CPUHP_ONLINE);
 748 }
 749
 750 /* Check for early params. */
 751 static int __init do_early_param(char *param, char *val,
 752                                  const char *unused, void *arg)
 753 {
 754         const struct obs_kernel_param *p;
 755
 756         for (p = __setup_start; p < __setup_end; p++) {
 757                 if (p->early && parameq(param, p->str)) {
 758                         if (p->setup_func(val) != 0)
 759                                 pr_warn("Malformed early option '%s'\n", param);
 760                 }
 761         }
 762         /* We accept everything at this stage. */
 763         return 0;
 764 }
 765
 766 void __init parse_early_options(char *cmdline)
 767 {
 768         parse_args("early options", cmdline, NULL, 0, 0, 0, NULL,
 769                    do_early_param);
 770 }
 771
 772 /* Arch code calls this early on, or if not, just before other parsing. */
 773 void __init parse_early_param(void)
 774 {
 775         static int done __initdata;
 776         static char tmp_cmdline[COMMAND_LINE_SIZE] __initdata;
 777
 778         if (done)
 779                 return;
 780
 781         /* All fall through to do_early_param. */
 782         strscpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);
 783         parse_early_options(tmp_cmdline);
 784         done = 1;
 785 }
 786
 787 void __init __weak arch_post_acpi_subsys_init(void) { }
 788
 789 void __init __weak smp_setup_processor_id(void)
 790 {
 791 }
 792
 793 void __init __weak smp_prepare_boot_cpu(void)
 794 {
 795 }
 796
 797 # if THREAD_SIZE >= PAGE_SIZE
 798 void __init __weak thread_stack_cache_init(void)
 799 {
 800 }
 801 #endif
 802
 803 void __init __weak poking_init(void) { }
 804
 805 void __init __weak pgtable_cache_init(void) { }
 806
 807 void __init __weak trap_init(void) { }
 808
 809 bool initcall_debug;
 810 core_param(initcall_debug, initcall_debug, bool, 0644);
 811
 812 #ifdef TRACEPOINTS_ENABLED
 813 static void __init initcall_debug_enable(void);
 814 #else
 815 static inline void initcall_debug_enable(void)
 816 {
 817 }
 818 #endif
 819
 820 #ifdef CONFIG_RANDOMIZE_KSTACK_OFFSET
 821 DEFINE_STATIC_KEY_MAYBE_RO(CONFIG_RANDOMIZE_KSTACK_OFFSET_DEFAULT,
 822                            randomize_kstack_offset);
 823 DEFINE_PER_CPU(u32, kstack_offset);
 824
 825 static int __init early_randomize_kstack_offset(char *buf)
 826 {
 827         int ret;
 828         bool bool_result;
 829
 830         ret = kstrtobool(buf, &bool_result);
 831         if (ret)
 832                 return ret;
 833
 834         if (bool_result)
 835                 static_branch_enable(&randomize_kstack_offset);
 836         else
 837                 static_branch_disable(&randomize_kstack_offset);
 838         return 0;
 839 }
 840 early_param("randomize_kstack_offset", early_randomize_kstack_offset);
 841 #endif
 842
 843 static void __init print_unknown_bootoptions(void)
 844 {
 845         char *unknown_options;
 846         char *end;
 847         const char *const *p;
 848         size_t len;
 849
 850         if (panic_later || (!argv_init[1] && !envp_init[2]))
 851                 return;
 852
 853         /*
 854          * Determine how many options we have to print out, plus a space
 855          * before each
 856          */
 857         len = 1; /* null terminator */
 858         for (p = &argv_init[1]; *p; p++) {
 859                 len++;
 860                 len += strlen(*p);
 861         }
 862         for (p = &envp_init[2]; *p; p++) {
 863                 len++;
 864                 len += strlen(*p);
 865         }
 866
 867         unknown_options = memblock_alloc(len, SMP_CACHE_BYTES);
 868         if (!unknown_options) {
 869                 pr_err("%s: Failed to allocate %zu bytes\n",
 870                         __func__, len);
 871                 return;
 872         }
 873         end = unknown_options;
 874
 875         for (p = &argv_init[1]; *p; p++)
 876                 end += sprintf(end, " %s", *p);
 877         for (p = &envp_init[2]; *p; p++)
 878                 end += sprintf(end, " %s", *p);
 879
 880         /* Start at unknown_options[1] to skip the initial space */
 881         pr_notice("Unknown kernel command line parameters \"%s\", will be passed to user space.\n",
 882                 &unknown_options[1]);
 883         memblock_free(unknown_options, len);
 884 }
 885
 886 static void __init early_numa_node_init(void)
 887 {
 888 #ifdef CONFIG_USE_PERCPU_NUMA_NODE_ID
 889 #ifndef cpu_to_node
 890         int cpu;
 891
 892         /* The early_cpu_to_node() should be ready here. */
 893         for_each_possible_cpu(cpu)
 894                 set_cpu_numa_node(cpu, early_cpu_to_node(cpu));
 895 #endif
 896 #endif
 897 }
 898
 899 asmlinkage __visible __init __no_sanitize_address __noreturn __no_stack_protector
 900 void start_kernel(void)
 901 {
 902         char *command_line;
 903         char *after_dashes;
 904
 905         set_task_stack_end_magic(&init_task);
 906         smp_setup_processor_id();
 907         debug_objects_early_init();
 908         init_vmlinux_build_id();
 909
 910         cgroup_init_early();
 911
 912         local_irq_disable();
 913         early_boot_irqs_disabled = true;
 914
 915         /*
 916          * Interrupts are still disabled. Do necessary setups, then
 917          * enable them.
 918          */
 919         boot_cpu_init();
 920         page_address_init();
 921         pr_notice("%s", linux_banner);
 922         setup_arch(&command_line);
 923         /* Static keys and static calls are needed by LSMs */
 924         jump_label_init();
 925         static_call_init();
 926         early_security_init();
 927         setup_boot_config();
 928         setup_command_line(command_line);
 929         setup_nr_cpu_ids();
 930         setup_per_cpu_areas();
 931         smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */
 932         early_numa_node_init();
 933         boot_cpu_hotplug_init();
 934
 935         pr_notice("Kernel command line: %s\n", saved_command_line);
 936         /* parameters may set static keys */
 937         parse_early_param();
 938         after_dashes = parse_args("Booting kernel",
 939                                   static_command_line, __start___param,
 940                                   __stop___param - __start___param,
 941                                   -1, -1, NULL, &unknown_bootoption);
 942         print_unknown_bootoptions();
 943         if (!IS_ERR_OR_NULL(after_dashes))
 944                 parse_args("Setting init args", after_dashes, NULL, 0, -1, -1,
 945                            NULL, set_init_arg);
 946         if (extra_init_args)
 947                 parse_args("Setting extra init args", extra_init_args,
 948                            NULL, 0, -1, -1, NULL, set_init_arg);
 949
 950         /* Architectural and non-timekeeping rng init, before allocator init */
 951         random_init_early(command_line);
 952
 953         /*
 954          * These use large bootmem allocations and must precede
 955          * initalization of page allocator
 956          */
 957         setup_log_buf(0);
 958         vfs_caches_init_early();
 959         sort_main_extable();
 960         trap_init();
 961         mm_core_init();
 962         poking_init();
 963         ftrace_init();
 964
 965         /* trace_printk can be enabled here */
 966         early_trace_init();
 967
 968         /*
 969          * Set up the scheduler prior starting any interrupts (such as the
 970          * timer interrupt). Full topology setup happens at smp_init()
 971          * time - but meanwhile we still have a functioning scheduler.
 972          */
 973         sched_init();
 974
 975         if (WARN(!irqs_disabled(),
 976                  "Interrupts were enabled *very* early, fixing it\n"))
 977                 local_irq_disable();
 978         radix_tree_init();
 979         maple_tree_init();
 980
 981         /*
 982          * Set up housekeeping before setting up workqueues to allow the unbound
 983          * workqueue to take non-housekeeping into account.
 984          */
 985         housekeeping_init();
 986
 987         /*
 988          * Allow workqueue creation and work item queueing/cancelling
 989          * early.  Work item execution depends on kthreads and starts after
 990          * workqueue_init().
 991          */
 992         workqueue_init_early();
 993
 994         rcu_init();
 995
 996         /* Trace events are available after this */
 997         trace_init();
 998
 999         if (initcall_debug)
1000                 initcall_debug_enable();
1001
1002         context_tracking_init();
1003         /* init some links before init_ISA_irqs() */
1004         early_irq_init();
1005         init_IRQ();
1006         tick_init();
1007         rcu_init_nohz();
1008         init_timers();
1009         srcu_init();
1010         hrtimers_init();
1011         softirq_init();
1012         timekeeping_init();
1013         time_init();
1014
1015         /* This must be after timekeeping is initialized */
1016         random_init();
1017
1018         /* These make use of the fully initialized rng */
1019         kfence_init();
1020         boot_init_stack_canary();
1021
1022         perf_event_init();
1023         profile_init();
1024         call_function_init();
1025         WARN(!irqs_disabled(), "Interrupts were enabled early\n");
1026
1027         early_boot_irqs_disabled = false;
1028         local_irq_enable();
1029
1030         kmem_cache_init_late();
1031
1032         /*
1033          * HACK ALERT! This is early. We're enabling the console before
1034          * we've done PCI setups etc, and console_init() must be aware of
1035          * this. But we do want output early, in case something goes wrong.
1036          */
1037         console_init();
1038         if (panic_later)
1039                 panic("Too many boot %s vars at `%s'", panic_later,
1040                       panic_param);
1041
1042         lockdep_init();
1043
1044         /*
1045          * Need to run this when irqs are enabled, because it wants
1046          * to self-test [hard/soft]-irqs on/off lock inversion bugs
1047          * too:
1048          */
1049         locking_selftest();
1050
1051 #ifdef CONFIG_BLK_DEV_INITRD
1052         if (initrd_start && !initrd_below_start_ok &&
1053             page_to_pfn(virt_to_page((void *)initrd_start)) < min_low_pfn) {
1054                 pr_crit("initrd overwritten (0x%08lx < 0x%08lx) - disabling it.\n",
1055                     page_to_pfn(virt_to_page((void *)initrd_start)),
1056                     min_low_pfn);
1057                 initrd_start = 0;
1058         }
1059 #endif
1060         setup_per_cpu_pageset();
1061         numa_policy_init();
1062         acpi_early_init();
1063         if (late_time_init)
1064                 late_time_init();
1065         sched_clock_init();
1066         calibrate_delay();
1067
1068         arch_cpu_finalize_init();
1069
1070         pid_idr_init();
1071         anon_vma_init();
1072 #ifdef CONFIG_X86
1073         if (efi_enabled(EFI_RUNTIME_SERVICES))
1074                 efi_enter_virtual_mode();
1075 #endif
1076         thread_stack_cache_init();
1077         cred_init();
1078         fork_init();
1079         proc_caches_init();
1080         uts_ns_init();
1081         key_init();
1082         security_init();
1083         dbg_late_init();
1084         net_ns_init();
1085         vfs_caches_init();
1086         pagecache_init();
1087         signals_init();
1088         seq_file_init();
1089         proc_root_init();
1090         nsfs_init();
1091         pidfs_init();
1092         cpuset_init();
1093         cgroup_init();
1094         taskstats_init_early();
1095         delayacct_init();
1096
1097         acpi_subsystem_init();
1098         arch_post_acpi_subsys_init();
1099         kcsan_init();
1100
1101         /* Do the rest non-__init'ed, we're now alive */
1102         rest_init();
1103
1104         /*
1105          * Avoid stack canaries in callers of boot_init_stack_canary for gcc-10
1106          * and older.
1107          */
1108 #if !__has_attribute(__no_stack_protector__)
1109         prevent_tail_call_optimization();
1110 #endif
1111 }
1112
1113 /* Call all constructor functions linked into the kernel. */
1114 static void __init do_ctors(void)
1115 {
1116 /*
1117  * For UML, the constructors have already been called by the
1118  * normal setup code as it's just a normal ELF binary, so we
1119  * cannot do it again - but we do need CONFIG_CONSTRUCTORS
1120  * even on UML for modules.
1121  */
1122 #if defined(CONFIG_CONSTRUCTORS) && !defined(CONFIG_UML)
1123         ctor_fn_t *fn = (ctor_fn_t *) __ctors_start;
1124
1125         for (; fn < (ctor_fn_t *) __ctors_end; fn++)
1126                 (*fn)();
1127 #endif
1128 }
1129
1130 #ifdef CONFIG_KALLSYMS
1131 struct blacklist_entry {
1132         struct list_head next;
1133         char *buf;
1134 };
1135
1136 static __initdata_or_module LIST_HEAD(blacklisted_initcalls);
1137
1138 static int __init initcall_blacklist(char *str)
1139 {
1140         char *str_entry;
1141         struct blacklist_entry *entry;
1142
1143         /* str argument is a comma-separated list of functions */
1144         do {
1145                 str_entry = strsep(&str, ",");
1146                 if (str_entry) {
1147                         pr_debug("blacklisting initcall %s\n", str_entry);
1148                         entry = memblock_alloc(sizeof(*entry),
1149                                                SMP_CACHE_BYTES);
1150                         if (!entry)
1151                                 panic("%s: Failed to allocate %zu bytes\n",
1152                                       __func__, sizeof(*entry));
1153                         entry->buf = memblock_alloc(strlen(str_entry) + 1,
1154                                                     SMP_CACHE_BYTES);
1155                         if (!entry->buf)
1156                                 panic("%s: Failed to allocate %zu bytes\n",
1157                                       __func__, strlen(str_entry) + 1);
1158                         strcpy(entry->buf, str_entry);
1159                         list_add(&entry->next, &blacklisted_initcalls);
1160                 }
1161         } while (str_entry);
1162
1163         return 1;
1164 }
1165
1166 static bool __init_or_module initcall_blacklisted(initcall_t fn)
1167 {
1168         struct blacklist_entry *entry;
1169         char fn_name[KSYM_SYMBOL_LEN];
1170         unsigned long addr;
1171
1172         if (list_empty(&blacklisted_initcalls))
1173                 return false;
1174
1175         addr = (unsigned long) dereference_function_descriptor(fn);
1176         sprint_symbol_no_offset(fn_name, addr);
1177
1178         /*
1179          * fn will be "function_name [module_name]" where [module_name] is not
1180          * displayed for built-in init functions.  Strip off the [module_name].
1181          */
1182         strreplace(fn_name, ' ', '\0');
1183
1184         list_for_each_entry(entry, &blacklisted_initcalls, next) {
1185                 if (!strcmp(fn_name, entry->buf)) {
1186                         pr_debug("initcall %s blacklisted\n", fn_name);
1187                         return true;
1188                 }
1189         }
1190
1191         return false;
1192 }
1193 #else
1194 static int __init initcall_blacklist(char *str)
1195 {
1196         pr_warn("initcall_blacklist requires CONFIG_KALLSYMS\n");
1197         return 0;
1198 }
1199
1200 static bool __init_or_module initcall_blacklisted(initcall_t fn)
1201 {
1202         return false;
1203 }
1204 #endif
1205 __setup("initcall_blacklist=", initcall_blacklist);
1206
1207 static __init_or_module void
1208 trace_initcall_start_cb(void *data, initcall_t fn)
1209 {
1210         ktime_t *calltime = data;
1211
1212         printk(KERN_DEBUG "calling  %pS @ %i\n", fn, task_pid_nr(current));
1213         *calltime = ktime_get();
1214 }
1215
1216 static __init_or_module void
1217 trace_initcall_finish_cb(void *data, initcall_t fn, int ret)
1218 {
1219         ktime_t rettime, *calltime = data;
1220
1221         rettime = ktime_get();
1222         printk(KERN_DEBUG "initcall %pS returned %d after %lld usecs\n",
1223                  fn, ret, (unsigned long long)ktime_us_delta(rettime, *calltime));
1224 }
1225
1226 static ktime_t initcall_calltime;
1227
1228 #ifdef TRACEPOINTS_ENABLED
1229 static void __init initcall_debug_enable(void)
1230 {
1231         int ret;
1232
1233         ret = register_trace_initcall_start(trace_initcall_start_cb,
1234                                             &initcall_calltime);
1235         ret |= register_trace_initcall_finish(trace_initcall_finish_cb,
1236                                               &initcall_calltime);
1237         WARN(ret, "Failed to register initcall tracepoints\n");
1238 }
1239 # define do_trace_initcall_start        trace_initcall_start
1240 # define do_trace_initcall_finish       trace_initcall_finish
1241 #else
1242 static inline void do_trace_initcall_start(initcall_t fn)
1243 {
1244         if (!initcall_debug)
1245                 return;
1246         trace_initcall_start_cb(&initcall_calltime, fn);
1247 }
1248 static inline void do_trace_initcall_finish(initcall_t fn, int ret)
1249 {
1250         if (!initcall_debug)
1251                 return;
1252         trace_initcall_finish_cb(&initcall_calltime, fn, ret);
1253 }
1254 #endif /* !TRACEPOINTS_ENABLED */
1255
1256 int __init_or_module do_one_initcall(initcall_t fn)
1257 {
1258         int count = preempt_count();
1259         char msgbuf[64];
1260         int ret;
1261
1262         if (initcall_blacklisted(fn))
1263                 return -EPERM;
1264
1265         do_trace_initcall_start(fn);
1266         ret = fn();
1267         do_trace_initcall_finish(fn, ret);
1268
1269         msgbuf[0] = 0;
1270
1271         if (preempt_count() != count) {
1272                 sprintf(msgbuf, "preemption imbalance ");
1273                 preempt_count_set(count);
1274         }
1275         if (irqs_disabled()) {
1276                 strlcat(msgbuf, "disabled interrupts ", sizeof(msgbuf));
1277                 local_irq_enable();
1278         }
1279         WARN(msgbuf[0], "initcall %pS returned with %s\n", fn, msgbuf);
1280
1281         add_latent_entropy();
1282         return ret;
1283 }
1284
1285
1286 static initcall_entry_t *initcall_levels[] __initdata = {
1287         __initcall0_start,
1288         __initcall1_start,
1289         __initcall2_start,
1290         __initcall3_start,
1291         __initcall4_start,
1292         __initcall5_start,
1293         __initcall6_start,
1294         __initcall7_start,
1295         __initcall_end,
1296 };
1297
1298 /* Keep these in sync with initcalls in include/linux/init.h */
1299 static const char *initcall_level_names[] __initdata = {
1300         "pure",
1301         "core",
1302         "postcore",
1303         "arch",
1304         "subsys",
1305         "fs",
1306         "device",
1307         "late",
1308 };
1309
1310 static int __init ignore_unknown_bootoption(char *param, char *val,
1311                                const char *unused, void *arg)
1312 {
1313         return 0;
1314 }
1315
1316 static void __init do_initcall_level(int level, char *command_line)
1317 {
1318         initcall_entry_t *fn;
1319
1320         parse_args(initcall_level_names[level],
1321                    command_line, __start___param,
1322                    __stop___param - __start___param,
1323                    level, level,
1324                    NULL, ignore_unknown_bootoption);
1325
1326         trace_initcall_level(initcall_level_names[level]);
1327         for (fn = initcall_levels[level]; fn < initcall_levels[level+1]; fn++)
1328                 do_one_initcall(initcall_from_entry(fn));
1329 }
1330
1331 static void __init do_initcalls(void)
1332 {
1333         int level;
1334         size_t len = saved_command_line_len + 1;
1335         char *command_line;
1336
1337         command_line = kzalloc(len, GFP_KERNEL);
1338         if (!command_line)
1339                 panic("%s: Failed to allocate %zu bytes\n", __func__, len);
1340
1341         for (level = 0; level < ARRAY_SIZE(initcall_levels) - 1; level++) {
1342                 /* Parser modifies command_line, restore it each time */
1343                 strcpy(command_line, saved_command_line);
1344                 do_initcall_level(level, command_line);
1345         }
1346
1347         kfree(command_line);
1348 }
1349
1350 /*
1351  * Ok, the machine is now initialized. None of the devices
1352  * have been touched yet, but the CPU subsystem is up and
1353  * running, and memory and process management works.
1354  *
1355  * Now we can finally start doing some real work..
1356  */
1357 static void __init do_basic_setup(void)
1358 {
1359         cpuset_init_smp();
1360         driver_init();
1361         init_irq_proc();
1362         do_ctors();
1363         do_initcalls();
1364 }
1365
1366 static void __init do_pre_smp_initcalls(void)
1367 {
1368         initcall_entry_t *fn;
1369
1370         trace_initcall_level("early");
1371         for (fn = __initcall_start; fn < __initcall0_start; fn++)
1372                 do_one_initcall(initcall_from_entry(fn));
1373 }
1374
1375 static int run_init_process(const char *init_filename)
1376 {
1377         const char *const *p;
1378
1379         argv_init[0] = init_filename;
1380         pr_info("Run %s as init process\n", init_filename);
1381         pr_debug("  with arguments:\n");
1382         for (p = argv_init; *p; p++)
1383                 pr_debug("    %s\n", *p);
1384         pr_debug("  with environment:\n");
1385         for (p = envp_init; *p; p++)
1386                 pr_debug("    %s\n", *p);
1387         return kernel_execve(init_filename, argv_init, envp_init);
1388 }
1389
1390 static int try_to_run_init_process(const char *init_filename)
1391 {
1392         int ret;
1393
1394         ret = run_init_process(init_filename);
1395
1396         if (ret && ret != -ENOENT) {
1397                 pr_err("Starting init: %s exists but couldn't execute it (error %d)\n",
1398                        init_filename, ret);
1399         }
1400
1401         return ret;
1402 }
1403
1404 static noinline void __init kernel_init_freeable(void);
1405
1406 #if defined(CONFIG_STRICT_KERNEL_RWX) || defined(CONFIG_STRICT_MODULE_RWX)
1407 bool rodata_enabled __ro_after_init = true;
1408
1409 #ifndef arch_parse_debug_rodata
1410 static inline bool arch_parse_debug_rodata(char *str) { return false; }
1411 #endif
1412
1413 static int __init set_debug_rodata(char *str)
1414 {
1415         if (arch_parse_debug_rodata(str))
1416                 return 0;
1417
1418         if (str && !strcmp(str, "on"))
1419                 rodata_enabled = true;
1420         else if (str && !strcmp(str, "off"))
1421                 rodata_enabled = false;
1422         else
1423                 pr_warn("Invalid option string for rodata: '%s'\n", str);
1424         return 0;
1425 }
1426 early_param("rodata", set_debug_rodata);
1427 #endif
1428
1429 static void mark_readonly(void)
1430 {
1431         if (IS_ENABLED(CONFIG_STRICT_KERNEL_RWX) && rodata_enabled) {
1432                 /*
1433                  * load_module() results in W+X mappings, which are cleaned
1434                  * up with init_free_wq. Let's make sure that queued work is
1435                  * flushed so that we don't hit false positives looking for
1436                  * insecure pages which are W+X.
1437                  */
1438                 flush_module_init_free_work();
1439                 jump_label_init_ro();
1440                 mark_rodata_ro();
1441                 debug_checkwx();
1442                 rodata_test();
1443         } else if (IS_ENABLED(CONFIG_STRICT_KERNEL_RWX)) {
1444                 pr_info("Kernel memory protection disabled.\n");
1445         } else if (IS_ENABLED(CONFIG_ARCH_HAS_STRICT_KERNEL_RWX)) {
1446                 pr_warn("Kernel memory protection not selected by kernel config.\n");
1447         } else {
1448                 pr_warn("This architecture does not have kernel memory protection.\n");
1449         }
1450 }
1451
1452 void __weak free_initmem(void)
1453 {
1454         free_initmem_default(POISON_FREE_INITMEM);
1455 }
1456
1457 static int __ref kernel_init(void *unused)
1458 {
1459         int ret;
1460
1461         /*
1462          * Wait until kthreadd is all set-up.
1463          */
1464         wait_for_completion(&kthreadd_done);
1465
1466         kernel_init_freeable();
1467         /* need to finish all async __init code before freeing the memory */
1468         async_synchronize_full();
1469
1470         system_state = SYSTEM_FREEING_INITMEM;
1471         kprobe_free_init_mem();
1472         ftrace_free_init_mem();
1473         kgdb_free_init_mem();
1474         exit_boot_config();
1475         free_initmem();
1476         mark_readonly();
1477
1478         /*
1479          * Kernel mappings are now finalized - update the userspace page-table
1480          * to finalize PTI.
1481          */
1482         pti_finalize();
1483
1484         system_state = SYSTEM_RUNNING;
1485         numa_default_policy();
1486
1487         rcu_end_inkernel_boot();
1488
1489         do_sysctl_args();
1490
1491         if (ramdisk_execute_command) {
1492                 ret = run_init_process(ramdisk_execute_command);
1493                 if (!ret)
1494                         return 0;
1495                 pr_err("Failed to execute %s (error %d)\n",
1496                        ramdisk_execute_command, ret);
1497         }
1498
1499         /*
1500          * We try each of these until one succeeds.
1501          *
1502          * The Bourne shell can be used instead of init if we are
1503          * trying to recover a really broken machine.
1504          */
1505         if (execute_command) {
1506                 ret = run_init_process(execute_command);
1507                 if (!ret)
1508                         return 0;
1509                 panic("Requested init %s failed (error %d).",
1510                       execute_command, ret);
1511         }
1512
1513         if (CONFIG_DEFAULT_INIT[0] != '\0') {
1514                 ret = run_init_process(CONFIG_DEFAULT_INIT);
1515                 if (ret)
1516                         pr_err("Default init %s failed (error %d)\n",
1517                                CONFIG_DEFAULT_INIT, ret);
1518                 else
1519                         return 0;
1520         }
1521
1522         if (!try_to_run_init_process("/sbin/init") ||
1523             !try_to_run_init_process("/etc/init") ||
1524             !try_to_run_init_process("/bin/init") ||
1525             !try_to_run_init_process("/bin/sh"))
1526                 return 0;
1527
1528         panic("No working init found.  Try passing init= option to kernel. "
1529               "See Linux Documentation/admin-guide/init.rst for guidance.");
1530 }
1531
1532 /* Open /dev/console, for stdin/stdout/stderr, this should never fail */
1533 void __init console_on_rootfs(void)
1534 {
1535         struct file *file = filp_open("/dev/console", O_RDWR, 0);
1536
1537         if (IS_ERR(file)) {
1538                 pr_err("Warning: unable to open an initial console.\n");
1539                 return;
1540         }
1541         init_dup(file);
1542         init_dup(file);
1543         init_dup(file);
1544         fput(file);
1545 }
1546
1547 static noinline void __init kernel_init_freeable(void)
1548 {
1549         /* Now the scheduler is fully set up and can do blocking allocations */
1550         gfp_allowed_mask = __GFP_BITS_MASK;
1551
1552         /*
1553          * init can allocate pages on any node
1554          */
1555         set_mems_allowed(node_states[N_MEMORY]);
1556
1557         cad_pid = get_pid(task_pid(current));
1558
1559         smp_prepare_cpus(setup_max_cpus);
1560
1561         workqueue_init();
1562
1563         init_mm_internals();
1564
1565         rcu_init_tasks_generic();
1566         do_pre_smp_initcalls();
1567         lockup_detector_init();
1568
1569         smp_init();
1570         sched_init_smp();
1571
1572         workqueue_init_topology();
1573         async_init();
1574         padata_init();
1575         page_alloc_init_late();
1576
1577         do_basic_setup();
1578
1579         kunit_run_all_tests();
1580
1581         wait_for_initramfs();
1582         console_on_rootfs();
1583
1584         /*
1585          * check if there is an early userspace init.  If yes, let it do all
1586          * the work
1587          */
1588         if (init_eaccess(ramdisk_execute_command) != 0) {
1589                 ramdisk_execute_command = NULL;
1590                 prepare_namespace();
1591         }
1592
1593         /*
1594          * Ok, we have completed the initial bootup, and
1595          * we're essentially up and running. Get rid of the
1596          * initmem segments and start the user-mode stuff..
1597          *
1598          * rootfs is available now, try loading the public keys
1599          * and default modules
1600          */
1601
1602         integrity_load_keys();
1603 }