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/list.h>
  92 #include <linux/integrity.h>
  93 #include <linux/proc_ns.h>
  94 #include <linux/io.h>
  95 #include <linux/cache.h>
  96 #include <linux/rodata_test.h>
  97 #include <linux/jump_label.h>
  98 #include <linux/mem_encrypt.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 <net/net_namespace.h>
 104
 105 #include <asm/io.h>
 106 #include <asm/bugs.h>
 107 #include <asm/setup.h>
 108 #include <asm/sections.h>
 109 #include <asm/cacheflush.h>
 110
 111 #define CREATE_TRACE_POINTS
 112 #include <trace/events/initcall.h>
 113
 114 #include <kunit/test.h>
 115
 116 static int kernel_init(void *);
 117
 118 extern void init_IRQ(void);
 119 extern void radix_tree_init(void);
 120 extern void maple_tree_init(void);
 121
 122 /*
 123  * Debug helper: via this flag we know that we are in 'early bootup code'
 124  * where only the boot processor is running with IRQ disabled.  This means
 125  * two things - IRQ must not be enabled before the flag is cleared and some
 126  * operations which are not allowed with IRQ disabled are allowed while the
 127  * flag is set.
 128  */
 129 bool early_boot_irqs_disabled __read_mostly;
 130
 131 enum system_states system_state __read_mostly;
 132 EXPORT_SYMBOL(system_state);
 133
 134 /*
 135  * Boot command-line arguments
 136  */
 137 #define MAX_INIT_ARGS CONFIG_INIT_ENV_ARG_LIMIT
 138 #define MAX_INIT_ENVS CONFIG_INIT_ENV_ARG_LIMIT
 139
 140 extern void time_init(void);
 141 /* Default late time init is NULL. archs can override this later. */
 142 void (*__initdata late_time_init)(void);
 143
 144 /* Untouched command line saved by arch-specific code. */
 145 char __initdata boot_command_line[COMMAND_LINE_SIZE];
 146 /* Untouched saved command line (eg. for /proc) */
 147 char *saved_command_line __ro_after_init;
 148 unsigned int saved_command_line_len __ro_after_init;
 149 /* Command line for parameter parsing */
 150 static char *static_command_line;
 151 /* Untouched extra command line */
 152 static char *extra_command_line;
 153 /* Extra init arguments */
 154 static char *extra_init_args;
 155
 156 #ifdef CONFIG_BOOT_CONFIG
 157 /* Is bootconfig on command line? */
 158 static bool bootconfig_found;
 159 static size_t initargs_offs;
 160 #else
 161 # define bootconfig_found false
 162 # define initargs_offs 0
 163 #endif
 164
 165 static char *execute_command;
 166 static char *ramdisk_execute_command = "/init";
 167
 168 /*
 169  * Used to generate warnings if static_key manipulation functions are used
 170  * before jump_label_init is called.
 171  */
 172 bool static_key_initialized __read_mostly;
 173 EXPORT_SYMBOL_GPL(static_key_initialized);
 174
 175 /*
 176  * If set, this is an indication to the drivers that reset the underlying
 177  * device before going ahead with the initialization otherwise driver might
 178  * rely on the BIOS and skip the reset operation.
 179  *
 180  * This is useful if kernel is booting in an unreliable environment.
 181  * For ex. kdump situation where previous kernel has crashed, BIOS has been
 182  * skipped and devices will be in unknown state.
 183  */
 184 unsigned int reset_devices;
 185 EXPORT_SYMBOL(reset_devices);
 186
 187 static int __init set_reset_devices(char *str)
 188 {
 189         reset_devices = 1;
 190         return 1;
 191 }
 192
 193 __setup("reset_devices", set_reset_devices);
 194
 195 static const char *argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
 196 const char *envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, };
 197 static const char *panic_later, *panic_param;
 198
 199 extern const struct obs_kernel_param __setup_start[], __setup_end[];
 200
 201 static bool __init obsolete_checksetup(char *line)
 202 {
 203         const struct obs_kernel_param *p;
 204         bool had_early_param = false;
 205
 206         p = __setup_start;
 207         do {
 208                 int n = strlen(p->str);
 209                 if (parameqn(line, p->str, n)) {
 210                         if (p->early) {
 211                                 /* Already done in parse_early_param?
 212                                  * (Needs exact match on param part).
 213                                  * Keep iterating, as we can have early
 214                                  * params and __setups of same names 8( */
 215                                 if (line[n] == '\0' || line[n] == '=')
 216                                         had_early_param = true;
 217                         } else if (!p->setup_func) {
 218                                 pr_warn("Parameter %s is obsolete, ignored\n",
 219                                         p->str);
 220                                 return true;
 221                         } else if (p->setup_func(line + n))
 222                                 return true;
 223                 }
 224                 p++;
 225         } while (p < __setup_end);
 226
 227         return had_early_param;
 228 }
 229
 230 /*
 231  * This should be approx 2 Bo*oMips to start (note initial shift), and will
 232  * still work even if initially too large, it will just take slightly longer
 233  */
 234 unsigned long loops_per_jiffy = (1<<12);
 235 EXPORT_SYMBOL(loops_per_jiffy);
 236
 237 static int __init debug_kernel(char *str)
 238 {
 239         console_loglevel = CONSOLE_LOGLEVEL_DEBUG;
 240         return 0;
 241 }
 242
 243 static int __init quiet_kernel(char *str)
 244 {
 245         console_loglevel = CONSOLE_LOGLEVEL_QUIET;
 246         return 0;
 247 }
 248
 249 early_param("debug", debug_kernel);
 250 early_param("quiet", quiet_kernel);
 251
 252 static int __init loglevel(char *str)
 253 {
 254         int newlevel;
 255
 256         /*
 257          * Only update loglevel value when a correct setting was passed,
 258          * to prevent blind crashes (when loglevel being set to 0) that
 259          * are quite hard to debug
 260          */
 261         if (get_option(&str, &newlevel)) {
 262                 console_loglevel = newlevel;
 263                 return 0;
 264         }
 265
 266         return -EINVAL;
 267 }
 268
 269 early_param("loglevel", loglevel);
 270
 271 #ifdef CONFIG_BLK_DEV_INITRD
 272 static void * __init get_boot_config_from_initrd(size_t *_size)
 273 {
 274         u32 size, csum;
 275         char *data;
 276         u32 *hdr;
 277         int i;
 278
 279         if (!initrd_end)
 280                 return NULL;
 281
 282         data = (char *)initrd_end - BOOTCONFIG_MAGIC_LEN;
 283         /*
 284          * Since Grub may align the size of initrd to 4, we must
 285          * check the preceding 3 bytes as well.
 286          */
 287         for (i = 0; i < 4; i++) {
 288                 if (!memcmp(data, BOOTCONFIG_MAGIC, BOOTCONFIG_MAGIC_LEN))
 289                         goto found;
 290                 data--;
 291         }
 292         return NULL;
 293
 294 found:
 295         hdr = (u32 *)(data - 8);
 296         size = le32_to_cpu(hdr[0]);
 297         csum = le32_to_cpu(hdr[1]);
 298
 299         data = ((void *)hdr) - size;
 300         if ((unsigned long)data < initrd_start) {
 301                 pr_err("bootconfig size %d is greater than initrd size %ld\n",
 302                         size, initrd_end - initrd_start);
 303                 return NULL;
 304         }
 305
 306         if (xbc_calc_checksum(data, size) != csum) {
 307                 pr_err("bootconfig checksum failed\n");
 308                 return NULL;
 309         }
 310
 311         /* Remove bootconfig from initramfs/initrd */
 312         initrd_end = (unsigned long)data;
 313         if (_size)
 314                 *_size = size;
 315
 316         return data;
 317 }
 318 #else
 319 static void * __init get_boot_config_from_initrd(size_t *_size)
 320 {
 321         return NULL;
 322 }
 323 #endif
 324
 325 #ifdef CONFIG_BOOT_CONFIG
 326
 327 static char xbc_namebuf[XBC_KEYLEN_MAX] __initdata;
 328
 329 #define rest(dst, end) ((end) > (dst) ? (end) - (dst) : 0)
 330
 331 static int __init xbc_snprint_cmdline(char *buf, size_t size,
 332                                       struct xbc_node *root)
 333 {
 334         struct xbc_node *knode, *vnode;
 335         char *end = buf + size;
 336         const char *val;
 337         int ret;
 338
 339         xbc_node_for_each_key_value(root, knode, val) {
 340                 ret = xbc_node_compose_key_after(root, knode,
 341                                         xbc_namebuf, XBC_KEYLEN_MAX);
 342                 if (ret < 0)
 343                         return ret;
 344
 345                 vnode = xbc_node_get_child(knode);
 346                 if (!vnode) {
 347                         ret = snprintf(buf, rest(buf, end), "%s ", xbc_namebuf);
 348                         if (ret < 0)
 349                                 return ret;
 350                         buf += ret;
 351                         continue;
 352                 }
 353                 xbc_array_for_each_value(vnode, val) {
 354                         ret = snprintf(buf, rest(buf, end), "%s=\"%s\" ",
 355                                        xbc_namebuf, val);
 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 /* Change NUL term back to "=", to make "param" the whole string. */
 497 static void __init repair_env_string(char *param, char *val)
 498 {
 499         if (val) {
 500                 /* param=val or param="val"? */
 501                 if (val == param+strlen(param)+1)
 502                         val[-1] = '=';
 503                 else if (val == param+strlen(param)+2) {
 504                         val[-2] = '=';
 505                         memmove(val-1, val, strlen(val)+1);
 506                 } else
 507                         BUG();
 508         }
 509 }
 510
 511 /* Anything after -- gets handed straight to init. */
 512 static int __init set_init_arg(char *param, char *val,
 513                                const char *unused, void *arg)
 514 {
 515         unsigned int i;
 516
 517         if (panic_later)
 518                 return 0;
 519
 520         repair_env_string(param, val);
 521
 522         for (i = 0; argv_init[i]; i++) {
 523                 if (i == MAX_INIT_ARGS) {
 524                         panic_later = "init";
 525                         panic_param = param;
 526                         return 0;
 527                 }
 528         }
 529         argv_init[i] = param;
 530         return 0;
 531 }
 532
 533 /*
 534  * Unknown boot options get handed to init, unless they look like
 535  * unused parameters (modprobe will find them in /proc/cmdline).
 536  */
 537 static int __init unknown_bootoption(char *param, char *val,
 538                                      const char *unused, void *arg)
 539 {
 540         size_t len = strlen(param);
 541
 542         repair_env_string(param, val);
 543
 544         /* Handle obsolete-style parameters */
 545         if (obsolete_checksetup(param))
 546                 return 0;
 547
 548         /* Unused module parameter. */
 549         if (strnchr(param, len, '.'))
 550                 return 0;
 551
 552         if (panic_later)
 553                 return 0;
 554
 555         if (val) {
 556                 /* Environment option */
 557                 unsigned int i;
 558                 for (i = 0; envp_init[i]; i++) {
 559                         if (i == MAX_INIT_ENVS) {
 560                                 panic_later = "env";
 561                                 panic_param = param;
 562                         }
 563                         if (!strncmp(param, envp_init[i], len+1))
 564                                 break;
 565                 }
 566                 envp_init[i] = param;
 567         } else {
 568                 /* Command line option */
 569                 unsigned int i;
 570                 for (i = 0; argv_init[i]; i++) {
 571                         if (i == MAX_INIT_ARGS) {
 572                                 panic_later = "init";
 573                                 panic_param = param;
 574                         }
 575                 }
 576                 argv_init[i] = param;
 577         }
 578         return 0;
 579 }
 580
 581 static int __init init_setup(char *str)
 582 {
 583         unsigned int i;
 584
 585         execute_command = str;
 586         /*
 587          * In case LILO is going to boot us with default command line,
 588          * it prepends "auto" before the whole cmdline which makes
 589          * the shell think it should execute a script with such name.
 590          * So we ignore all arguments entered _before_ init=... [MJ]
 591          */
 592         for (i = 1; i < MAX_INIT_ARGS; i++)
 593                 argv_init[i] = NULL;
 594         return 1;
 595 }
 596 __setup("init=", init_setup);
 597
 598 static int __init rdinit_setup(char *str)
 599 {
 600         unsigned int i;
 601
 602         ramdisk_execute_command = str;
 603         /* See "auto" comment in init_setup */
 604         for (i = 1; i < MAX_INIT_ARGS; i++)
 605                 argv_init[i] = NULL;
 606         return 1;
 607 }
 608 __setup("rdinit=", rdinit_setup);
 609
 610 #ifndef CONFIG_SMP
 611 static const unsigned int setup_max_cpus = NR_CPUS;
 612 static inline void setup_nr_cpu_ids(void) { }
 613 static inline void smp_prepare_cpus(unsigned int maxcpus) { }
 614 #endif
 615
 616 /*
 617  * We need to store the untouched command line for future reference.
 618  * We also need to store the touched command line since the parameter
 619  * parsing is performed in place, and we should allow a component to
 620  * store reference of name/value for future reference.
 621  */
 622 static void __init setup_command_line(char *command_line)
 623 {
 624         size_t len, xlen = 0, ilen = 0;
 625
 626         if (extra_command_line)
 627                 xlen = strlen(extra_command_line);
 628         if (extra_init_args)
 629                 ilen = strlen(extra_init_args) + 4; /* for " -- " */
 630
 631         len = xlen + strlen(boot_command_line) + 1;
 632
 633         saved_command_line = memblock_alloc(len + ilen, SMP_CACHE_BYTES);
 634         if (!saved_command_line)
 635                 panic("%s: Failed to allocate %zu bytes\n", __func__, len + ilen);
 636
 637         static_command_line = memblock_alloc(len, SMP_CACHE_BYTES);
 638         if (!static_command_line)
 639                 panic("%s: Failed to allocate %zu bytes\n", __func__, len);
 640
 641         if (xlen) {
 642                 /*
 643                  * We have to put extra_command_line before boot command
 644                  * lines because there could be dashes (separator of init
 645                  * command line) in the command lines.
 646                  */
 647                 strcpy(saved_command_line, extra_command_line);
 648                 strcpy(static_command_line, extra_command_line);
 649         }
 650         strcpy(saved_command_line + xlen, boot_command_line);
 651         strcpy(static_command_line + xlen, command_line);
 652
 653         if (ilen) {
 654                 /*
 655                  * Append supplemental init boot args to saved_command_line
 656                  * so that user can check what command line options passed
 657                  * to init.
 658                  * The order should always be
 659                  * " -- "[bootconfig init-param][cmdline init-param]
 660                  */
 661                 if (initargs_offs) {
 662                         len = xlen + initargs_offs;
 663                         strcpy(saved_command_line + len, extra_init_args);
 664                         len += ilen - 4;        /* strlen(extra_init_args) */
 665                         strcpy(saved_command_line + len,
 666                                 boot_command_line + initargs_offs - 1);
 667                 } else {
 668                         len = strlen(saved_command_line);
 669                         strcpy(saved_command_line + len, " -- ");
 670                         len += 4;
 671                         strcpy(saved_command_line + len, extra_init_args);
 672                 }
 673         }
 674
 675         saved_command_line_len = strlen(saved_command_line);
 676 }
 677
 678 /*
 679  * We need to finalize in a non-__init function or else race conditions
 680  * between the root thread and the init thread may cause start_kernel to
 681  * be reaped by free_initmem before the root thread has proceeded to
 682  * cpu_idle.
 683  *
 684  * gcc-3.4 accidentally inlines this function, so use noinline.
 685  */
 686
 687 static __initdata DECLARE_COMPLETION(kthreadd_done);
 688
 689 noinline void __ref __noreturn rest_init(void)
 690 {
 691         struct task_struct *tsk;
 692         int pid;
 693
 694         rcu_scheduler_starting();
 695         /*
 696          * We need to spawn init first so that it obtains pid 1, however
 697          * the init task will end up wanting to create kthreads, which, if
 698          * we schedule it before we create kthreadd, will OOPS.
 699          */
 700         pid = user_mode_thread(kernel_init, NULL, CLONE_FS);
 701         /*
 702          * Pin init on the boot CPU. Task migration is not properly working
 703          * until sched_init_smp() has been run. It will set the allowed
 704          * CPUs for init to the non isolated CPUs.
 705          */
 706         rcu_read_lock();
 707         tsk = find_task_by_pid_ns(pid, &init_pid_ns);
 708         tsk->flags |= PF_NO_SETAFFINITY;
 709         set_cpus_allowed_ptr(tsk, cpumask_of(smp_processor_id()));
 710         rcu_read_unlock();
 711
 712         numa_default_policy();
 713         pid = kernel_thread(kthreadd, NULL, NULL, CLONE_FS | CLONE_FILES);
 714         rcu_read_lock();
 715         kthreadd_task = find_task_by_pid_ns(pid, &init_pid_ns);
 716         rcu_read_unlock();
 717
 718         /*
 719          * Enable might_sleep() and smp_processor_id() checks.
 720          * They cannot be enabled earlier because with CONFIG_PREEMPTION=y
 721          * kernel_thread() would trigger might_sleep() splats. With
 722          * CONFIG_PREEMPT_VOLUNTARY=y the init task might have scheduled
 723          * already, but it's stuck on the kthreadd_done completion.
 724          */
 725         system_state = SYSTEM_SCHEDULING;
 726
 727         complete(&kthreadd_done);
 728
 729         /*
 730          * The boot idle thread must execute schedule()
 731          * at least once to get things moving:
 732          */
 733         schedule_preempt_disabled();
 734         /* Call into cpu_idle with preempt disabled */
 735         cpu_startup_entry(CPUHP_ONLINE);
 736 }
 737
 738 /* Check for early params. */
 739 static int __init do_early_param(char *param, char *val,
 740                                  const char *unused, void *arg)
 741 {
 742         const struct obs_kernel_param *p;
 743
 744         for (p = __setup_start; p < __setup_end; p++) {
 745                 if ((p->early && parameq(param, p->str)) ||
 746                     (strcmp(param, "console") == 0 &&
 747                      strcmp(p->str, "earlycon") == 0)
 748                 ) {
 749                         if (p->setup_func(val) != 0)
 750                                 pr_warn("Malformed early option '%s'\n", param);
 751                 }
 752         }
 753         /* We accept everything at this stage. */
 754         return 0;
 755 }
 756
 757 void __init parse_early_options(char *cmdline)
 758 {
 759         parse_args("early options", cmdline, NULL, 0, 0, 0, NULL,
 760                    do_early_param);
 761 }
 762
 763 /* Arch code calls this early on, or if not, just before other parsing. */
 764 void __init parse_early_param(void)
 765 {
 766         static int done __initdata;
 767         static char tmp_cmdline[COMMAND_LINE_SIZE] __initdata;
 768
 769         if (done)
 770                 return;
 771
 772         /* All fall through to do_early_param. */
 773         strscpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);
 774         parse_early_options(tmp_cmdline);
 775         done = 1;
 776 }
 777
 778 void __init __weak arch_post_acpi_subsys_init(void) { }
 779
 780 void __init __weak smp_setup_processor_id(void)
 781 {
 782 }
 783
 784 # if THREAD_SIZE >= PAGE_SIZE
 785 void __init __weak thread_stack_cache_init(void)
 786 {
 787 }
 788 #endif
 789
 790 void __init __weak mem_encrypt_init(void) { }
 791
 792 void __init __weak poking_init(void) { }
 793
 794 void __init __weak pgtable_cache_init(void) { }
 795
 796 void __init __weak trap_init(void) { }
 797
 798 bool initcall_debug;
 799 core_param(initcall_debug, initcall_debug, bool, 0644);
 800
 801 #ifdef TRACEPOINTS_ENABLED
 802 static void __init initcall_debug_enable(void);
 803 #else
 804 static inline void initcall_debug_enable(void)
 805 {
 806 }
 807 #endif
 808
 809 #ifdef CONFIG_RANDOMIZE_KSTACK_OFFSET
 810 DEFINE_STATIC_KEY_MAYBE_RO(CONFIG_RANDOMIZE_KSTACK_OFFSET_DEFAULT,
 811                            randomize_kstack_offset);
 812 DEFINE_PER_CPU(u32, kstack_offset);
 813
 814 static int __init early_randomize_kstack_offset(char *buf)
 815 {
 816         int ret;
 817         bool bool_result;
 818
 819         ret = kstrtobool(buf, &bool_result);
 820         if (ret)
 821                 return ret;
 822
 823         if (bool_result)
 824                 static_branch_enable(&randomize_kstack_offset);
 825         else
 826                 static_branch_disable(&randomize_kstack_offset);
 827         return 0;
 828 }
 829 early_param("randomize_kstack_offset", early_randomize_kstack_offset);
 830 #endif
 831
 832 void __init __weak __noreturn arch_call_rest_init(void)
 833 {
 834         rest_init();
 835 }
 836
 837 static void __init print_unknown_bootoptions(void)
 838 {
 839         char *unknown_options;
 840         char *end;
 841         const char *const *p;
 842         size_t len;
 843
 844         if (panic_later || (!argv_init[1] && !envp_init[2]))
 845                 return;
 846
 847         /*
 848          * Determine how many options we have to print out, plus a space
 849          * before each
 850          */
 851         len = 1; /* null terminator */
 852         for (p = &argv_init[1]; *p; p++) {
 853                 len++;
 854                 len += strlen(*p);
 855         }
 856         for (p = &envp_init[2]; *p; p++) {
 857                 len++;
 858                 len += strlen(*p);
 859         }
 860
 861         unknown_options = memblock_alloc(len, SMP_CACHE_BYTES);
 862         if (!unknown_options) {
 863                 pr_err("%s: Failed to allocate %zu bytes\n",
 864                         __func__, len);
 865                 return;
 866         }
 867         end = unknown_options;
 868
 869         for (p = &argv_init[1]; *p; p++)
 870                 end += sprintf(end, " %s", *p);
 871         for (p = &envp_init[2]; *p; p++)
 872                 end += sprintf(end, " %s", *p);
 873
 874         /* Start at unknown_options[1] to skip the initial space */
 875         pr_notice("Unknown kernel command line parameters \"%s\", will be passed to user space.\n",
 876                 &unknown_options[1]);
 877         memblock_free(unknown_options, len);
 878 }
 879
 880 asmlinkage __visible void __init __no_sanitize_address __noreturn start_kernel(void)
 881 {
 882         char *command_line;
 883         char *after_dashes;
 884
 885         set_task_stack_end_magic(&init_task);
 886         smp_setup_processor_id();
 887         debug_objects_early_init();
 888         init_vmlinux_build_id();
 889
 890         cgroup_init_early();
 891
 892         local_irq_disable();
 893         early_boot_irqs_disabled = true;
 894
 895         /*
 896          * Interrupts are still disabled. Do necessary setups, then
 897          * enable them.
 898          */
 899         boot_cpu_init();
 900         page_address_init();
 901         pr_notice("%s", linux_banner);
 902         early_security_init();
 903         setup_arch(&command_line);
 904         setup_boot_config();
 905         setup_command_line(command_line);
 906         setup_nr_cpu_ids();
 907         setup_per_cpu_areas();
 908         smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */
 909         boot_cpu_hotplug_init();
 910
 911         pr_notice("Kernel command line: %s\n", saved_command_line);
 912         /* parameters may set static keys */
 913         jump_label_init();
 914         parse_early_param();
 915         after_dashes = parse_args("Booting kernel",
 916                                   static_command_line, __start___param,
 917                                   __stop___param - __start___param,
 918                                   -1, -1, NULL, &unknown_bootoption);
 919         print_unknown_bootoptions();
 920         if (!IS_ERR_OR_NULL(after_dashes))
 921                 parse_args("Setting init args", after_dashes, NULL, 0, -1, -1,
 922                            NULL, set_init_arg);
 923         if (extra_init_args)
 924                 parse_args("Setting extra init args", extra_init_args,
 925                            NULL, 0, -1, -1, NULL, set_init_arg);
 926
 927         /* Architectural and non-timekeeping rng init, before allocator init */
 928         random_init_early(command_line);
 929
 930         /*
 931          * These use large bootmem allocations and must precede
 932          * initalization of page allocator
 933          */
 934         setup_log_buf(0);
 935         vfs_caches_init_early();
 936         sort_main_extable();
 937         trap_init();
 938         mm_core_init();
 939         poking_init();
 940         ftrace_init();
 941
 942         /* trace_printk can be enabled here */
 943         early_trace_init();
 944
 945         /*
 946          * Set up the scheduler prior starting any interrupts (such as the
 947          * timer interrupt). Full topology setup happens at smp_init()
 948          * time - but meanwhile we still have a functioning scheduler.
 949          */
 950         sched_init();
 951
 952         if (WARN(!irqs_disabled(),
 953                  "Interrupts were enabled *very* early, fixing it\n"))
 954                 local_irq_disable();
 955         radix_tree_init();
 956         maple_tree_init();
 957
 958         /*
 959          * Set up housekeeping before setting up workqueues to allow the unbound
 960          * workqueue to take non-housekeeping into account.
 961          */
 962         housekeeping_init();
 963
 964         /*
 965          * Allow workqueue creation and work item queueing/cancelling
 966          * early.  Work item execution depends on kthreads and starts after
 967          * workqueue_init().
 968          */
 969         workqueue_init_early();
 970
 971         rcu_init();
 972
 973         /* Trace events are available after this */
 974         trace_init();
 975
 976         if (initcall_debug)
 977                 initcall_debug_enable();
 978
 979         context_tracking_init();
 980         /* init some links before init_ISA_irqs() */
 981         early_irq_init();
 982         init_IRQ();
 983         tick_init();
 984         rcu_init_nohz();
 985         init_timers();
 986         srcu_init();
 987         hrtimers_init();
 988         softirq_init();
 989         timekeeping_init();
 990         time_init();
 991
 992         /* This must be after timekeeping is initialized */
 993         random_init();
 994
 995         /* These make use of the fully initialized rng */
 996         kfence_init();
 997         boot_init_stack_canary();
 998
 999         perf_event_init();
1000         profile_init();
1001         call_function_init();
1002         WARN(!irqs_disabled(), "Interrupts were enabled early\n");
1003
1004         early_boot_irqs_disabled = false;
1005         local_irq_enable();
1006
1007         kmem_cache_init_late();
1008
1009         /*
1010          * HACK ALERT! This is early. We're enabling the console before
1011          * we've done PCI setups etc, and console_init() must be aware of
1012          * this. But we do want output early, in case something goes wrong.
1013          */
1014         console_init();
1015         if (panic_later)
1016                 panic("Too many boot %s vars at `%s'", panic_later,
1017                       panic_param);
1018
1019         lockdep_init();
1020
1021         /*
1022          * Need to run this when irqs are enabled, because it wants
1023          * to self-test [hard/soft]-irqs on/off lock inversion bugs
1024          * too:
1025          */
1026         locking_selftest();
1027
1028 #ifdef CONFIG_BLK_DEV_INITRD
1029         if (initrd_start && !initrd_below_start_ok &&
1030             page_to_pfn(virt_to_page((void *)initrd_start)) < min_low_pfn) {
1031                 pr_crit("initrd overwritten (0x%08lx < 0x%08lx) - disabling it.\n",
1032                     page_to_pfn(virt_to_page((void *)initrd_start)),
1033                     min_low_pfn);
1034                 initrd_start = 0;
1035         }
1036 #endif
1037         setup_per_cpu_pageset();
1038         numa_policy_init();
1039         acpi_early_init();
1040         if (late_time_init)
1041                 late_time_init();
1042         sched_clock_init();
1043         calibrate_delay();
1044
1045         /*
1046          * This needs to be called before any devices perform DMA
1047          * operations that might use the SWIOTLB bounce buffers. It will
1048          * mark the bounce buffers as decrypted so that their usage will
1049          * not cause "plain-text" data to be decrypted when accessed. It
1050          * must be called after late_time_init() so that Hyper-V x86/x64
1051          * hypercalls work when the SWIOTLB bounce buffers are decrypted.
1052          */
1053         mem_encrypt_init();
1054
1055         pid_idr_init();
1056         anon_vma_init();
1057 #ifdef CONFIG_X86
1058         if (efi_enabled(EFI_RUNTIME_SERVICES))
1059                 efi_enter_virtual_mode();
1060 #endif
1061         thread_stack_cache_init();
1062         cred_init();
1063         fork_init();
1064         proc_caches_init();
1065         uts_ns_init();
1066         key_init();
1067         security_init();
1068         dbg_late_init();
1069         net_ns_init();
1070         vfs_caches_init();
1071         pagecache_init();
1072         signals_init();
1073         seq_file_init();
1074         proc_root_init();
1075         nsfs_init();
1076         cpuset_init();
1077         cgroup_init();
1078         taskstats_init_early();
1079         delayacct_init();
1080
1081         check_bugs();
1082
1083         acpi_subsystem_init();
1084         arch_post_acpi_subsys_init();
1085         kcsan_init();
1086
1087         /* Do the rest non-__init'ed, we're now alive */
1088         arch_call_rest_init();
1089
1090         prevent_tail_call_optimization();
1091 }
1092
1093 /* Call all constructor functions linked into the kernel. */
1094 static void __init do_ctors(void)
1095 {
1096 /*
1097  * For UML, the constructors have already been called by the
1098  * normal setup code as it's just a normal ELF binary, so we
1099  * cannot do it again - but we do need CONFIG_CONSTRUCTORS
1100  * even on UML for modules.
1101  */
1102 #if defined(CONFIG_CONSTRUCTORS) && !defined(CONFIG_UML)
1103         ctor_fn_t *fn = (ctor_fn_t *) __ctors_start;
1104
1105         for (; fn < (ctor_fn_t *) __ctors_end; fn++)
1106                 (*fn)();
1107 #endif
1108 }
1109
1110 #ifdef CONFIG_KALLSYMS
1111 struct blacklist_entry {
1112         struct list_head next;
1113         char *buf;
1114 };
1115
1116 static __initdata_or_module LIST_HEAD(blacklisted_initcalls);
1117
1118 static int __init initcall_blacklist(char *str)
1119 {
1120         char *str_entry;
1121         struct blacklist_entry *entry;
1122
1123         /* str argument is a comma-separated list of functions */
1124         do {
1125                 str_entry = strsep(&str, ",");
1126                 if (str_entry) {
1127                         pr_debug("blacklisting initcall %s\n", str_entry);
1128                         entry = memblock_alloc(sizeof(*entry),
1129                                                SMP_CACHE_BYTES);
1130                         if (!entry)
1131                                 panic("%s: Failed to allocate %zu bytes\n",
1132                                       __func__, sizeof(*entry));
1133                         entry->buf = memblock_alloc(strlen(str_entry) + 1,
1134                                                     SMP_CACHE_BYTES);
1135                         if (!entry->buf)
1136                                 panic("%s: Failed to allocate %zu bytes\n",
1137                                       __func__, strlen(str_entry) + 1);
1138                         strcpy(entry->buf, str_entry);
1139                         list_add(&entry->next, &blacklisted_initcalls);
1140                 }
1141         } while (str_entry);
1142
1143         return 1;
1144 }
1145
1146 static bool __init_or_module initcall_blacklisted(initcall_t fn)
1147 {
1148         struct blacklist_entry *entry;
1149         char fn_name[KSYM_SYMBOL_LEN];
1150         unsigned long addr;
1151
1152         if (list_empty(&blacklisted_initcalls))
1153                 return false;
1154
1155         addr = (unsigned long) dereference_function_descriptor(fn);
1156         sprint_symbol_no_offset(fn_name, addr);
1157
1158         /*
1159          * fn will be "function_name [module_name]" where [module_name] is not
1160          * displayed for built-in init functions.  Strip off the [module_name].
1161          */
1162         strreplace(fn_name, ' ', '\0');
1163
1164         list_for_each_entry(entry, &blacklisted_initcalls, next) {
1165                 if (!strcmp(fn_name, entry->buf)) {
1166                         pr_debug("initcall %s blacklisted\n", fn_name);
1167                         return true;
1168                 }
1169         }
1170
1171         return false;
1172 }
1173 #else
1174 static int __init initcall_blacklist(char *str)
1175 {
1176         pr_warn("initcall_blacklist requires CONFIG_KALLSYMS\n");
1177         return 0;
1178 }
1179
1180 static bool __init_or_module initcall_blacklisted(initcall_t fn)
1181 {
1182         return false;
1183 }
1184 #endif
1185 __setup("initcall_blacklist=", initcall_blacklist);
1186
1187 static __init_or_module void
1188 trace_initcall_start_cb(void *data, initcall_t fn)
1189 {
1190         ktime_t *calltime = data;
1191
1192         printk(KERN_DEBUG "calling  %pS @ %i\n", fn, task_pid_nr(current));
1193         *calltime = ktime_get();
1194 }
1195
1196 static __init_or_module void
1197 trace_initcall_finish_cb(void *data, initcall_t fn, int ret)
1198 {
1199         ktime_t rettime, *calltime = data;
1200
1201         rettime = ktime_get();
1202         printk(KERN_DEBUG "initcall %pS returned %d after %lld usecs\n",
1203                  fn, ret, (unsigned long long)ktime_us_delta(rettime, *calltime));
1204 }
1205
1206 static ktime_t initcall_calltime;
1207
1208 #ifdef TRACEPOINTS_ENABLED
1209 static void __init initcall_debug_enable(void)
1210 {
1211         int ret;
1212
1213         ret = register_trace_initcall_start(trace_initcall_start_cb,
1214                                             &initcall_calltime);
1215         ret |= register_trace_initcall_finish(trace_initcall_finish_cb,
1216                                               &initcall_calltime);
1217         WARN(ret, "Failed to register initcall tracepoints\n");
1218 }
1219 # define do_trace_initcall_start        trace_initcall_start
1220 # define do_trace_initcall_finish       trace_initcall_finish
1221 #else
1222 static inline void do_trace_initcall_start(initcall_t fn)
1223 {
1224         if (!initcall_debug)
1225                 return;
1226         trace_initcall_start_cb(&initcall_calltime, fn);
1227 }
1228 static inline void do_trace_initcall_finish(initcall_t fn, int ret)
1229 {
1230         if (!initcall_debug)
1231                 return;
1232         trace_initcall_finish_cb(&initcall_calltime, fn, ret);
1233 }
1234 #endif /* !TRACEPOINTS_ENABLED */
1235
1236 int __init_or_module do_one_initcall(initcall_t fn)
1237 {
1238         int count = preempt_count();
1239         char msgbuf[64];
1240         int ret;
1241
1242         if (initcall_blacklisted(fn))
1243                 return -EPERM;
1244
1245         do_trace_initcall_start(fn);
1246         ret = fn();
1247         do_trace_initcall_finish(fn, ret);
1248
1249         msgbuf[0] = 0;
1250
1251         if (preempt_count() != count) {
1252                 sprintf(msgbuf, "preemption imbalance ");
1253                 preempt_count_set(count);
1254         }
1255         if (irqs_disabled()) {
1256                 strlcat(msgbuf, "disabled interrupts ", sizeof(msgbuf));
1257                 local_irq_enable();
1258         }
1259         WARN(msgbuf[0], "initcall %pS returned with %s\n", fn, msgbuf);
1260
1261         add_latent_entropy();
1262         return ret;
1263 }
1264
1265
1266 extern initcall_entry_t __initcall_start[];
1267 extern initcall_entry_t __initcall0_start[];
1268 extern initcall_entry_t __initcall1_start[];
1269 extern initcall_entry_t __initcall2_start[];
1270 extern initcall_entry_t __initcall3_start[];
1271 extern initcall_entry_t __initcall4_start[];
1272 extern initcall_entry_t __initcall5_start[];
1273 extern initcall_entry_t __initcall6_start[];
1274 extern initcall_entry_t __initcall7_start[];
1275 extern initcall_entry_t __initcall_end[];
1276
1277 static initcall_entry_t *initcall_levels[] __initdata = {
1278         __initcall0_start,
1279         __initcall1_start,
1280         __initcall2_start,
1281         __initcall3_start,
1282         __initcall4_start,
1283         __initcall5_start,
1284         __initcall6_start,
1285         __initcall7_start,
1286         __initcall_end,
1287 };
1288
1289 /* Keep these in sync with initcalls in include/linux/init.h */
1290 static const char *initcall_level_names[] __initdata = {
1291         "pure",
1292         "core",
1293         "postcore",
1294         "arch",
1295         "subsys",
1296         "fs",
1297         "device",
1298         "late",
1299 };
1300
1301 static int __init ignore_unknown_bootoption(char *param, char *val,
1302                                const char *unused, void *arg)
1303 {
1304         return 0;
1305 }
1306
1307 static void __init do_initcall_level(int level, char *command_line)
1308 {
1309         initcall_entry_t *fn;
1310
1311         parse_args(initcall_level_names[level],
1312                    command_line, __start___param,
1313                    __stop___param - __start___param,
1314                    level, level,
1315                    NULL, ignore_unknown_bootoption);
1316
1317         trace_initcall_level(initcall_level_names[level]);
1318         for (fn = initcall_levels[level]; fn < initcall_levels[level+1]; fn++)
1319                 do_one_initcall(initcall_from_entry(fn));
1320 }
1321
1322 static void __init do_initcalls(void)
1323 {
1324         int level;
1325         size_t len = saved_command_line_len + 1;
1326         char *command_line;
1327
1328         command_line = kzalloc(len, GFP_KERNEL);
1329         if (!command_line)
1330                 panic("%s: Failed to allocate %zu bytes\n", __func__, len);
1331
1332         for (level = 0; level < ARRAY_SIZE(initcall_levels) - 1; level++) {
1333                 /* Parser modifies command_line, restore it each time */
1334                 strcpy(command_line, saved_command_line);
1335                 do_initcall_level(level, command_line);
1336         }
1337
1338         kfree(command_line);
1339 }
1340
1341 /*
1342  * Ok, the machine is now initialized. None of the devices
1343  * have been touched yet, but the CPU subsystem is up and
1344  * running, and memory and process management works.
1345  *
1346  * Now we can finally start doing some real work..
1347  */
1348 static void __init do_basic_setup(void)
1349 {
1350         cpuset_init_smp();
1351         driver_init();
1352         init_irq_proc();
1353         do_ctors();
1354         do_initcalls();
1355 }
1356
1357 static void __init do_pre_smp_initcalls(void)
1358 {
1359         initcall_entry_t *fn;
1360
1361         trace_initcall_level("early");
1362         for (fn = __initcall_start; fn < __initcall0_start; fn++)
1363                 do_one_initcall(initcall_from_entry(fn));
1364 }
1365
1366 static int run_init_process(const char *init_filename)
1367 {
1368         const char *const *p;
1369
1370         argv_init[0] = init_filename;
1371         pr_info("Run %s as init process\n", init_filename);
1372         pr_debug("  with arguments:\n");
1373         for (p = argv_init; *p; p++)
1374                 pr_debug("    %s\n", *p);
1375         pr_debug("  with environment:\n");
1376         for (p = envp_init; *p; p++)
1377                 pr_debug("    %s\n", *p);
1378         return kernel_execve(init_filename, argv_init, envp_init);
1379 }
1380
1381 static int try_to_run_init_process(const char *init_filename)
1382 {
1383         int ret;
1384
1385         ret = run_init_process(init_filename);
1386
1387         if (ret && ret != -ENOENT) {
1388                 pr_err("Starting init: %s exists but couldn't execute it (error %d)\n",
1389                        init_filename, ret);
1390         }
1391
1392         return ret;
1393 }
1394
1395 static noinline void __init kernel_init_freeable(void);
1396
1397 #if defined(CONFIG_STRICT_KERNEL_RWX) || defined(CONFIG_STRICT_MODULE_RWX)
1398 bool rodata_enabled __ro_after_init = true;
1399
1400 #ifndef arch_parse_debug_rodata
1401 static inline bool arch_parse_debug_rodata(char *str) { return false; }
1402 #endif
1403
1404 static int __init set_debug_rodata(char *str)
1405 {
1406         if (arch_parse_debug_rodata(str))
1407                 return 0;
1408
1409         if (str && !strcmp(str, "on"))
1410                 rodata_enabled = true;
1411         else if (str && !strcmp(str, "off"))
1412                 rodata_enabled = false;
1413         else
1414                 pr_warn("Invalid option string for rodata: '%s'\n", str);
1415         return 0;
1416 }
1417 early_param("rodata", set_debug_rodata);
1418 #endif
1419
1420 #ifdef CONFIG_STRICT_KERNEL_RWX
1421 static void mark_readonly(void)
1422 {
1423         if (rodata_enabled) {
1424                 /*
1425                  * load_module() results in W+X mappings, which are cleaned
1426                  * up with call_rcu().  Let's make sure that queued work is
1427                  * flushed so that we don't hit false positives looking for
1428                  * insecure pages which are W+X.
1429                  */
1430                 rcu_barrier();
1431                 mark_rodata_ro();
1432                 rodata_test();
1433         } else
1434                 pr_info("Kernel memory protection disabled.\n");
1435 }
1436 #elif defined(CONFIG_ARCH_HAS_STRICT_KERNEL_RWX)
1437 static inline void mark_readonly(void)
1438 {
1439         pr_warn("Kernel memory protection not selected by kernel config.\n");
1440 }
1441 #else
1442 static inline void mark_readonly(void)
1443 {
1444         pr_warn("This architecture does not have kernel memory protection.\n");
1445 }
1446 #endif
1447
1448 void __weak free_initmem(void)
1449 {
1450         free_initmem_default(POISON_FREE_INITMEM);
1451 }
1452
1453 static int __ref kernel_init(void *unused)
1454 {
1455         int ret;
1456
1457         /*
1458          * Wait until kthreadd is all set-up.
1459          */
1460         wait_for_completion(&kthreadd_done);
1461
1462         kernel_init_freeable();
1463         /* need to finish all async __init code before freeing the memory */
1464         async_synchronize_full();
1465
1466         system_state = SYSTEM_FREEING_INITMEM;
1467         kprobe_free_init_mem();
1468         ftrace_free_init_mem();
1469         kgdb_free_init_mem();
1470         exit_boot_config();
1471         free_initmem();
1472         mark_readonly();
1473
1474         /*
1475          * Kernel mappings are now finalized - update the userspace page-table
1476          * to finalize PTI.
1477          */
1478         pti_finalize();
1479
1480         system_state = SYSTEM_RUNNING;
1481         numa_default_policy();
1482
1483         rcu_end_inkernel_boot();
1484
1485         do_sysctl_args();
1486
1487         if (ramdisk_execute_command) {
1488                 ret = run_init_process(ramdisk_execute_command);
1489                 if (!ret)
1490                         return 0;
1491                 pr_err("Failed to execute %s (error %d)\n",
1492                        ramdisk_execute_command, ret);
1493         }
1494
1495         /*
1496          * We try each of these until one succeeds.
1497          *
1498          * The Bourne shell can be used instead of init if we are
1499          * trying to recover a really broken machine.
1500          */
1501         if (execute_command) {
1502                 ret = run_init_process(execute_command);
1503                 if (!ret)
1504                         return 0;
1505                 panic("Requested init %s failed (error %d).",
1506                       execute_command, ret);
1507         }
1508
1509         if (CONFIG_DEFAULT_INIT[0] != '\0') {
1510                 ret = run_init_process(CONFIG_DEFAULT_INIT);
1511                 if (ret)
1512                         pr_err("Default init %s failed (error %d)\n",
1513                                CONFIG_DEFAULT_INIT, ret);
1514                 else
1515                         return 0;
1516         }
1517
1518         if (!try_to_run_init_process("/sbin/init") ||
1519             !try_to_run_init_process("/etc/init") ||
1520             !try_to_run_init_process("/bin/init") ||
1521             !try_to_run_init_process("/bin/sh"))
1522                 return 0;
1523
1524         panic("No working init found.  Try passing init= option to kernel. "
1525               "See Linux Documentation/admin-guide/init.rst for guidance.");
1526 }
1527
1528 /* Open /dev/console, for stdin/stdout/stderr, this should never fail */
1529 void __init console_on_rootfs(void)
1530 {
1531         struct file *file = filp_open("/dev/console", O_RDWR, 0);
1532
1533         if (IS_ERR(file)) {
1534                 pr_err("Warning: unable to open an initial console.\n");
1535                 return;
1536         }
1537         init_dup(file);
1538         init_dup(file);
1539         init_dup(file);
1540         fput(file);
1541 }
1542
1543 static noinline void __init kernel_init_freeable(void)
1544 {
1545         /* Now the scheduler is fully set up and can do blocking allocations */
1546         gfp_allowed_mask = __GFP_BITS_MASK;
1547
1548         /*
1549          * init can allocate pages on any node
1550          */
1551         set_mems_allowed(node_states[N_MEMORY]);
1552
1553         cad_pid = get_pid(task_pid(current));
1554
1555         smp_prepare_cpus(setup_max_cpus);
1556
1557         workqueue_init();
1558
1559         init_mm_internals();
1560
1561         rcu_init_tasks_generic();
1562         do_pre_smp_initcalls();
1563         lockup_detector_init();
1564
1565         smp_init();
1566         sched_init_smp();
1567
1568         padata_init();
1569         page_alloc_init_late();
1570
1571         do_basic_setup();
1572
1573         kunit_run_all_tests();
1574
1575         wait_for_initramfs();
1576         console_on_rootfs();
1577
1578         /*
1579          * check if there is an early userspace init.  If yes, let it do all
1580          * the work
1581          */
1582         if (init_eaccess(ramdisk_execute_command) != 0) {
1583                 ramdisk_execute_command = NULL;
1584                 prepare_namespace();
1585         }
1586
1587         /*
1588          * Ok, we have completed the initial bootup, and
1589          * we're essentially up and running. Get rid of the
1590          * initmem segments and start the user-mode stuff..
1591          *
1592          * rootfs is available now, try loading the public keys
1593          * and default modules
1594          */
1595
1596         integrity_load_keys();
1597 }