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
set_reset_devices(char * str)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
obsolete_checksetup(char * line)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
debug_kernel(char * str)231 static int __init debug_kernel(char *str)
232 {
233 console_loglevel = CONSOLE_LOGLEVEL_DEBUG;
234 return 0;
235 }
236
quiet_kernel(char * str)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
loglevel(char * str)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
get_boot_config_from_initrd(size_t * _size)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
get_boot_config_from_initrd(size_t * _size)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
xbc_snprint_cmdline(char * buf,size_t size,struct xbc_node * root)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 */
xbc_make_cmdline(const char * key)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
bootconfig_params(char * param,char * val,const char * unused,void * arg)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
warn_bootconfig(char * str)407 static int __init warn_bootconfig(char *str)
408 {
409 /* The 'bootconfig' has been handled by bootconfig_params(). */
410 return 0;
411 }
412
setup_boot_config(void)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
exit_boot_config(void)471 static void __init exit_boot_config(void)
472 {
473 xbc_exit();
474 }
475
476 #else /* !CONFIG_BOOT_CONFIG */
477
setup_boot_config(void)478 static void __init setup_boot_config(void)
479 {
480 /* Remove bootconfig data from initrd */
481 get_boot_config_from_initrd(NULL);
482 }
483
warn_bootconfig(char * str)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
cmdline_has_extra_options(void)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. */
repair_env_string(char * param,char * val)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. */
set_init_arg(char * param,char * val,const char * unused,void * arg)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 */
unknown_bootoption(char * param,char * val,const char * unused,void * arg)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
init_setup(char * str)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
rdinit_setup(char * str)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
setup_nr_cpu_ids(void)620 static inline void setup_nr_cpu_ids(void) { }
smp_prepare_cpus(unsigned int maxcpus)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 */
setup_command_line(char * command_line)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
rest_init(void)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. */
do_early_param(char * param,char * val,const char * unused,void * arg)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
parse_early_options(char * cmdline)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. */
parse_early_param(void)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
arch_post_acpi_subsys_init(void)787 void __init __weak arch_post_acpi_subsys_init(void) { }
788
smp_setup_processor_id(void)789 void __init __weak smp_setup_processor_id(void)
790 {
791 }
792
smp_prepare_boot_cpu(void)793 void __init __weak smp_prepare_boot_cpu(void)
794 {
795 }
796
797 # if THREAD_SIZE >= PAGE_SIZE
thread_stack_cache_init(void)798 void __init __weak thread_stack_cache_init(void)
799 {
800 }
801 #endif
802
poking_init(void)803 void __init __weak poking_init(void) { }
804
pgtable_cache_init(void)805 void __init __weak pgtable_cache_init(void) { }
806
trap_init(void)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
initcall_debug_enable(void)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
early_randomize_kstack_offset(char * buf)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
print_unknown_bootoptions(void)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
early_numa_node_init(void)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
start_kernel(void)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. */
do_ctors(void)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
initcall_blacklist(char * str)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
initcall_blacklisted(initcall_t fn)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
initcall_blacklist(char * str)1194 static int __init initcall_blacklist(char *str)
1195 {
1196 pr_warn("initcall_blacklist requires CONFIG_KALLSYMS\n");
1197 return 0;
1198 }
1199
initcall_blacklisted(initcall_t fn)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
trace_initcall_start_cb(void * data,initcall_t fn)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
trace_initcall_finish_cb(void * data,initcall_t fn,int ret)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
initcall_debug_enable(void)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
do_trace_initcall_start(initcall_t fn)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 }
do_trace_initcall_finish(initcall_t fn,int ret)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
do_one_initcall(initcall_t fn)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
ignore_unknown_bootoption(char * param,char * val,const char * unused,void * arg)1310 static int __init ignore_unknown_bootoption(char *param, char *val,
1311 const char *unused, void *arg)
1312 {
1313 return 0;
1314 }
1315
do_initcall_level(int level,char * command_line)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
do_initcalls(void)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 */
do_basic_setup(void)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
do_pre_smp_initcalls(void)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
run_init_process(const char * init_filename)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
try_to_run_init_process(const char * init_filename)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
arch_parse_debug_rodata(char * str)1410 static inline bool arch_parse_debug_rodata(char *str) { return false; }
1411 #endif
1412
set_debug_rodata(char * str)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
mark_readonly(void)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
free_initmem(void)1452 void __weak free_initmem(void)
1453 {
1454 free_initmem_default(POISON_FREE_INITMEM);
1455 }
1456
kernel_init(void * unused)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 */
console_on_rootfs(void)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
kernel_init_freeable(void)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 }
1604