xref: /linux/init/main.c (revision 6fbd6cf85a3be127454a1ad58525a3adcf8612ab)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  *  linux/init/main.c
4  *
5  *  Copyright (C) 1991, 1992  Linus Torvalds
6  *
7  *  GK 2/5/95  -  Changed to support mounting root fs via NFS
8  *  Added initrd & change_root: Werner Almesberger & Hans Lermen, Feb '96
9  *  Moan early if gcc is old, avoiding bogus kernels - Paul Gortmaker, May '96
10  *  Simplified starting of init:  Michael A. Griffith <grif@acm.org>
11  */
12 
13 #define DEBUG		/* Enable initcall_debug */
14 
15 #include <linux/types.h>
16 #include <linux/extable.h>
17 #include <linux/module.h>
18 #include <linux/proc_fs.h>
19 #include <linux/binfmts.h>
20 #include <linux/kernel.h>
21 #include <linux/syscalls.h>
22 #include <linux/stackprotector.h>
23 #include <linux/string.h>
24 #include <linux/ctype.h>
25 #include <linux/delay.h>
26 #include <linux/ioport.h>
27 #include <linux/init.h>
28 #include <linux/initrd.h>
29 #include <linux/memblock.h>
30 #include <linux/acpi.h>
31 #include <linux/bootconfig.h>
32 #include <linux/console.h>
33 #include <linux/nmi.h>
34 #include <linux/percpu.h>
35 #include <linux/kmod.h>
36 #include <linux/kprobes.h>
37 #include <linux/vmalloc.h>
38 #include <linux/kernel_stat.h>
39 #include <linux/start_kernel.h>
40 #include <linux/security.h>
41 #include <linux/smp.h>
42 #include <linux/profile.h>
43 #include <linux/rcupdate.h>
44 #include <linux/moduleparam.h>
45 #include <linux/kallsyms.h>
46 #include <linux/writeback.h>
47 #include <linux/cpu.h>
48 #include <linux/cpuset.h>
49 #include <linux/cgroup.h>
50 #include <linux/efi.h>
51 #include <linux/tick.h>
52 #include <linux/sched/isolation.h>
53 #include <linux/interrupt.h>
54 #include <linux/taskstats_kern.h>
55 #include <linux/delayacct.h>
56 #include <linux/unistd.h>
57 #include <linux/utsname.h>
58 #include <linux/rmap.h>
59 #include <linux/mempolicy.h>
60 #include <linux/key.h>
61 #include <linux/page_ext.h>
62 #include <linux/debug_locks.h>
63 #include <linux/debugobjects.h>
64 #include <linux/lockdep.h>
65 #include <linux/kmemleak.h>
66 #include <linux/padata.h>
67 #include <linux/pid_namespace.h>
68 #include <linux/device/driver.h>
69 #include <linux/kthread.h>
70 #include <linux/sched.h>
71 #include <linux/sched/init.h>
72 #include <linux/signal.h>
73 #include <linux/idr.h>
74 #include <linux/kgdb.h>
75 #include <linux/ftrace.h>
76 #include <linux/async.h>
77 #include <linux/shmem_fs.h>
78 #include <linux/slab.h>
79 #include <linux/perf_event.h>
80 #include <linux/ptrace.h>
81 #include <linux/pti.h>
82 #include <linux/blkdev.h>
83 #include <linux/elevator.h>
84 #include <linux/sched/clock.h>
85 #include <linux/sched/task.h>
86 #include <linux/sched/task_stack.h>
87 #include <linux/context_tracking.h>
88 #include <linux/random.h>
89 #include <linux/list.h>
90 #include <linux/integrity.h>
91 #include <linux/proc_ns.h>
92 #include <linux/io.h>
93 #include <linux/cache.h>
94 #include <linux/rodata_test.h>
95 #include <linux/jump_label.h>
96 #include <linux/mem_encrypt.h>
97 #include <linux/kcsan.h>
98 #include <linux/init_syscalls.h>
99 
100 #include <asm/io.h>
101 #include <asm/bugs.h>
102 #include <asm/setup.h>
103 #include <asm/sections.h>
104 #include <asm/cacheflush.h>
105 
106 #define CREATE_TRACE_POINTS
107 #include <trace/events/initcall.h>
108 
109 #include <kunit/test.h>
110 
111 static int kernel_init(void *);
112 
113 extern void init_IRQ(void);
114 extern void radix_tree_init(void);
115 
116 /*
117  * Debug helper: via this flag we know that we are in 'early bootup code'
118  * where only the boot processor is running with IRQ disabled.  This means
119  * two things - IRQ must not be enabled before the flag is cleared and some
120  * operations which are not allowed with IRQ disabled are allowed while the
121  * flag is set.
122  */
123 bool early_boot_irqs_disabled __read_mostly;
124 
125 enum system_states system_state __read_mostly;
126 EXPORT_SYMBOL(system_state);
127 
128 /*
129  * Boot command-line arguments
130  */
131 #define MAX_INIT_ARGS CONFIG_INIT_ENV_ARG_LIMIT
132 #define MAX_INIT_ENVS CONFIG_INIT_ENV_ARG_LIMIT
133 
134 extern void time_init(void);
135 /* Default late time init is NULL. archs can override this later. */
136 void (*__initdata late_time_init)(void);
137 
138 /* Untouched command line saved by arch-specific code. */
139 char __initdata boot_command_line[COMMAND_LINE_SIZE];
140 /* Untouched saved command line (eg. for /proc) */
141 char *saved_command_line;
142 /* Command line for parameter parsing */
143 static char *static_command_line;
144 /* Untouched extra command line */
145 static char *extra_command_line;
146 /* Extra init arguments */
147 static char *extra_init_args;
148 
149 #ifdef CONFIG_BOOT_CONFIG
150 /* Is bootconfig on command line? */
151 static bool bootconfig_found;
152 static bool initargs_found;
153 #else
154 # define bootconfig_found false
155 # define initargs_found false
156 #endif
157 
158 static char *execute_command;
159 static char *ramdisk_execute_command = "/init";
160 
161 /*
162  * Used to generate warnings if static_key manipulation functions are used
163  * before jump_label_init is called.
164  */
165 bool static_key_initialized __read_mostly;
166 EXPORT_SYMBOL_GPL(static_key_initialized);
167 
168 /*
169  * If set, this is an indication to the drivers that reset the underlying
170  * device before going ahead with the initialization otherwise driver might
171  * rely on the BIOS and skip the reset operation.
172  *
173  * This is useful if kernel is booting in an unreliable environment.
174  * For ex. kdump situation where previous kernel has crashed, BIOS has been
175  * skipped and devices will be in unknown state.
176  */
177 unsigned int reset_devices;
178 EXPORT_SYMBOL(reset_devices);
179 
180 static int __init set_reset_devices(char *str)
181 {
182 	reset_devices = 1;
183 	return 1;
184 }
185 
186 __setup("reset_devices", set_reset_devices);
187 
188 static const char *argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
189 const char *envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, };
190 static const char *panic_later, *panic_param;
191 
192 extern const struct obs_kernel_param __setup_start[], __setup_end[];
193 
194 static bool __init obsolete_checksetup(char *line)
195 {
196 	const struct obs_kernel_param *p;
197 	bool had_early_param = false;
198 
199 	p = __setup_start;
200 	do {
201 		int n = strlen(p->str);
202 		if (parameqn(line, p->str, n)) {
203 			if (p->early) {
204 				/* Already done in parse_early_param?
205 				 * (Needs exact match on param part).
206 				 * Keep iterating, as we can have early
207 				 * params and __setups of same names 8( */
208 				if (line[n] == '\0' || line[n] == '=')
209 					had_early_param = true;
210 			} else if (!p->setup_func) {
211 				pr_warn("Parameter %s is obsolete, ignored\n",
212 					p->str);
213 				return true;
214 			} else if (p->setup_func(line + n))
215 				return true;
216 		}
217 		p++;
218 	} while (p < __setup_end);
219 
220 	return had_early_param;
221 }
222 
223 /*
224  * This should be approx 2 Bo*oMips to start (note initial shift), and will
225  * still work even if initially too large, it will just take slightly longer
226  */
227 unsigned long loops_per_jiffy = (1<<12);
228 EXPORT_SYMBOL(loops_per_jiffy);
229 
230 static int __init debug_kernel(char *str)
231 {
232 	console_loglevel = CONSOLE_LOGLEVEL_DEBUG;
233 	return 0;
234 }
235 
236 static int __init quiet_kernel(char *str)
237 {
238 	console_loglevel = CONSOLE_LOGLEVEL_QUIET;
239 	return 0;
240 }
241 
242 early_param("debug", debug_kernel);
243 early_param("quiet", quiet_kernel);
244 
245 static int __init loglevel(char *str)
246 {
247 	int newlevel;
248 
249 	/*
250 	 * Only update loglevel value when a correct setting was passed,
251 	 * to prevent blind crashes (when loglevel being set to 0) that
252 	 * are quite hard to debug
253 	 */
254 	if (get_option(&str, &newlevel)) {
255 		console_loglevel = newlevel;
256 		return 0;
257 	}
258 
259 	return -EINVAL;
260 }
261 
262 early_param("loglevel", loglevel);
263 
264 #ifdef CONFIG_BLK_DEV_INITRD
265 static void * __init get_boot_config_from_initrd(u32 *_size, u32 *_csum)
266 {
267 	u32 size, csum;
268 	char *data;
269 	u32 *hdr;
270 	int i;
271 
272 	if (!initrd_end)
273 		return NULL;
274 
275 	data = (char *)initrd_end - BOOTCONFIG_MAGIC_LEN;
276 	/*
277 	 * Since Grub may align the size of initrd to 4, we must
278 	 * check the preceding 3 bytes as well.
279 	 */
280 	for (i = 0; i < 4; i++) {
281 		if (!memcmp(data, BOOTCONFIG_MAGIC, BOOTCONFIG_MAGIC_LEN))
282 			goto found;
283 		data--;
284 	}
285 	return NULL;
286 
287 found:
288 	hdr = (u32 *)(data - 8);
289 	size = le32_to_cpu(hdr[0]);
290 	csum = le32_to_cpu(hdr[1]);
291 
292 	data = ((void *)hdr) - size;
293 	if ((unsigned long)data < initrd_start) {
294 		pr_err("bootconfig size %d is greater than initrd size %ld\n",
295 			size, initrd_end - initrd_start);
296 		return NULL;
297 	}
298 
299 	/* Remove bootconfig from initramfs/initrd */
300 	initrd_end = (unsigned long)data;
301 	if (_size)
302 		*_size = size;
303 	if (_csum)
304 		*_csum = csum;
305 
306 	return data;
307 }
308 #else
309 static void * __init get_boot_config_from_initrd(u32 *_size, u32 *_csum)
310 {
311 	return NULL;
312 }
313 #endif
314 
315 #ifdef CONFIG_BOOT_CONFIG
316 
317 static char xbc_namebuf[XBC_KEYLEN_MAX] __initdata;
318 
319 #define rest(dst, end) ((end) > (dst) ? (end) - (dst) : 0)
320 
321 static int __init xbc_snprint_cmdline(char *buf, size_t size,
322 				      struct xbc_node *root)
323 {
324 	struct xbc_node *knode, *vnode;
325 	char *end = buf + size;
326 	const char *val;
327 	int ret;
328 
329 	xbc_node_for_each_key_value(root, knode, val) {
330 		ret = xbc_node_compose_key_after(root, knode,
331 					xbc_namebuf, XBC_KEYLEN_MAX);
332 		if (ret < 0)
333 			return ret;
334 
335 		vnode = xbc_node_get_child(knode);
336 		if (!vnode) {
337 			ret = snprintf(buf, rest(buf, end), "%s ", xbc_namebuf);
338 			if (ret < 0)
339 				return ret;
340 			buf += ret;
341 			continue;
342 		}
343 		xbc_array_for_each_value(vnode, val) {
344 			ret = snprintf(buf, rest(buf, end), "%s=\"%s\" ",
345 				       xbc_namebuf, val);
346 			if (ret < 0)
347 				return ret;
348 			buf += ret;
349 		}
350 	}
351 
352 	return buf - (end - size);
353 }
354 #undef rest
355 
356 /* Make an extra command line under given key word */
357 static char * __init xbc_make_cmdline(const char *key)
358 {
359 	struct xbc_node *root;
360 	char *new_cmdline;
361 	int ret, len = 0;
362 
363 	root = xbc_find_node(key);
364 	if (!root)
365 		return NULL;
366 
367 	/* Count required buffer size */
368 	len = xbc_snprint_cmdline(NULL, 0, root);
369 	if (len <= 0)
370 		return NULL;
371 
372 	new_cmdline = memblock_alloc(len + 1, SMP_CACHE_BYTES);
373 	if (!new_cmdline) {
374 		pr_err("Failed to allocate memory for extra kernel cmdline.\n");
375 		return NULL;
376 	}
377 
378 	ret = xbc_snprint_cmdline(new_cmdline, len + 1, root);
379 	if (ret < 0 || ret > len) {
380 		pr_err("Failed to print extra kernel cmdline.\n");
381 		return NULL;
382 	}
383 
384 	return new_cmdline;
385 }
386 
387 static u32 boot_config_checksum(unsigned char *p, u32 size)
388 {
389 	u32 ret = 0;
390 
391 	while (size--)
392 		ret += *p++;
393 
394 	return ret;
395 }
396 
397 static int __init bootconfig_params(char *param, char *val,
398 				    const char *unused, void *arg)
399 {
400 	if (strcmp(param, "bootconfig") == 0) {
401 		bootconfig_found = true;
402 	}
403 	return 0;
404 }
405 
406 static void __init setup_boot_config(const char *cmdline)
407 {
408 	static char tmp_cmdline[COMMAND_LINE_SIZE] __initdata;
409 	const char *msg;
410 	int pos;
411 	u32 size, csum;
412 	char *data, *copy, *err;
413 	int ret;
414 
415 	/* Cut out the bootconfig data even if we have no bootconfig option */
416 	data = get_boot_config_from_initrd(&size, &csum);
417 
418 	strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);
419 	err = parse_args("bootconfig", tmp_cmdline, NULL, 0, 0, 0, NULL,
420 			 bootconfig_params);
421 
422 	if (IS_ERR(err) || !bootconfig_found)
423 		return;
424 
425 	/* parse_args() stops at '--' and returns an address */
426 	if (err)
427 		initargs_found = true;
428 
429 	if (!data) {
430 		pr_err("'bootconfig' found on command line, but no bootconfig found\n");
431 		return;
432 	}
433 
434 	if (size >= XBC_DATA_MAX) {
435 		pr_err("bootconfig size %d greater than max size %d\n",
436 			size, XBC_DATA_MAX);
437 		return;
438 	}
439 
440 	if (boot_config_checksum((unsigned char *)data, size) != csum) {
441 		pr_err("bootconfig checksum failed\n");
442 		return;
443 	}
444 
445 	copy = memblock_alloc(size + 1, SMP_CACHE_BYTES);
446 	if (!copy) {
447 		pr_err("Failed to allocate memory for bootconfig\n");
448 		return;
449 	}
450 
451 	memcpy(copy, data, size);
452 	copy[size] = '\0';
453 
454 	ret = xbc_init(copy, &msg, &pos);
455 	if (ret < 0) {
456 		if (pos < 0)
457 			pr_err("Failed to init bootconfig: %s.\n", msg);
458 		else
459 			pr_err("Failed to parse bootconfig: %s at %d.\n",
460 				msg, pos);
461 	} else {
462 		pr_info("Load bootconfig: %d bytes %d nodes\n", size, ret);
463 		/* keys starting with "kernel." are passed via cmdline */
464 		extra_command_line = xbc_make_cmdline("kernel");
465 		/* Also, "init." keys are init arguments */
466 		extra_init_args = xbc_make_cmdline("init");
467 	}
468 	return;
469 }
470 
471 #else
472 
473 static void __init setup_boot_config(const char *cmdline)
474 {
475 	/* Remove bootconfig data from initrd */
476 	get_boot_config_from_initrd(NULL, NULL);
477 }
478 
479 static int __init warn_bootconfig(char *str)
480 {
481 	pr_warn("WARNING: 'bootconfig' found on the kernel command line but CONFIG_BOOT_CONFIG is not set.\n");
482 	return 0;
483 }
484 early_param("bootconfig", warn_bootconfig);
485 
486 #endif
487 
488 /* Change NUL term back to "=", to make "param" the whole string. */
489 static void __init repair_env_string(char *param, char *val)
490 {
491 	if (val) {
492 		/* param=val or param="val"? */
493 		if (val == param+strlen(param)+1)
494 			val[-1] = '=';
495 		else if (val == param+strlen(param)+2) {
496 			val[-2] = '=';
497 			memmove(val-1, val, strlen(val)+1);
498 		} else
499 			BUG();
500 	}
501 }
502 
503 /* Anything after -- gets handed straight to init. */
504 static int __init set_init_arg(char *param, char *val,
505 			       const char *unused, void *arg)
506 {
507 	unsigned int i;
508 
509 	if (panic_later)
510 		return 0;
511 
512 	repair_env_string(param, val);
513 
514 	for (i = 0; argv_init[i]; i++) {
515 		if (i == MAX_INIT_ARGS) {
516 			panic_later = "init";
517 			panic_param = param;
518 			return 0;
519 		}
520 	}
521 	argv_init[i] = param;
522 	return 0;
523 }
524 
525 /*
526  * Unknown boot options get handed to init, unless they look like
527  * unused parameters (modprobe will find them in /proc/cmdline).
528  */
529 static int __init unknown_bootoption(char *param, char *val,
530 				     const char *unused, void *arg)
531 {
532 	size_t len = strlen(param);
533 
534 	repair_env_string(param, val);
535 
536 	/* Handle obsolete-style parameters */
537 	if (obsolete_checksetup(param))
538 		return 0;
539 
540 	/* Unused module parameter. */
541 	if (strnchr(param, len, '.'))
542 		return 0;
543 
544 	if (panic_later)
545 		return 0;
546 
547 	if (val) {
548 		/* Environment option */
549 		unsigned int i;
550 		for (i = 0; envp_init[i]; i++) {
551 			if (i == MAX_INIT_ENVS) {
552 				panic_later = "env";
553 				panic_param = param;
554 			}
555 			if (!strncmp(param, envp_init[i], len+1))
556 				break;
557 		}
558 		envp_init[i] = param;
559 	} else {
560 		/* Command line option */
561 		unsigned int i;
562 		for (i = 0; argv_init[i]; i++) {
563 			if (i == MAX_INIT_ARGS) {
564 				panic_later = "init";
565 				panic_param = param;
566 			}
567 		}
568 		argv_init[i] = param;
569 	}
570 	return 0;
571 }
572 
573 static int __init init_setup(char *str)
574 {
575 	unsigned int i;
576 
577 	execute_command = str;
578 	/*
579 	 * In case LILO is going to boot us with default command line,
580 	 * it prepends "auto" before the whole cmdline which makes
581 	 * the shell think it should execute a script with such name.
582 	 * So we ignore all arguments entered _before_ init=... [MJ]
583 	 */
584 	for (i = 1; i < MAX_INIT_ARGS; i++)
585 		argv_init[i] = NULL;
586 	return 1;
587 }
588 __setup("init=", init_setup);
589 
590 static int __init rdinit_setup(char *str)
591 {
592 	unsigned int i;
593 
594 	ramdisk_execute_command = str;
595 	/* See "auto" comment in init_setup */
596 	for (i = 1; i < MAX_INIT_ARGS; i++)
597 		argv_init[i] = NULL;
598 	return 1;
599 }
600 __setup("rdinit=", rdinit_setup);
601 
602 #ifndef CONFIG_SMP
603 static const unsigned int setup_max_cpus = NR_CPUS;
604 static inline void setup_nr_cpu_ids(void) { }
605 static inline void smp_prepare_cpus(unsigned int maxcpus) { }
606 #endif
607 
608 /*
609  * We need to store the untouched command line for future reference.
610  * We also need to store the touched command line since the parameter
611  * parsing is performed in place, and we should allow a component to
612  * store reference of name/value for future reference.
613  */
614 static void __init setup_command_line(char *command_line)
615 {
616 	size_t len, xlen = 0, ilen = 0;
617 
618 	if (extra_command_line)
619 		xlen = strlen(extra_command_line);
620 	if (extra_init_args)
621 		ilen = strlen(extra_init_args) + 4; /* for " -- " */
622 
623 	len = xlen + strlen(boot_command_line) + 1;
624 
625 	saved_command_line = memblock_alloc(len + ilen, SMP_CACHE_BYTES);
626 	if (!saved_command_line)
627 		panic("%s: Failed to allocate %zu bytes\n", __func__, len + ilen);
628 
629 	static_command_line = memblock_alloc(len, SMP_CACHE_BYTES);
630 	if (!static_command_line)
631 		panic("%s: Failed to allocate %zu bytes\n", __func__, len);
632 
633 	if (xlen) {
634 		/*
635 		 * We have to put extra_command_line before boot command
636 		 * lines because there could be dashes (separator of init
637 		 * command line) in the command lines.
638 		 */
639 		strcpy(saved_command_line, extra_command_line);
640 		strcpy(static_command_line, extra_command_line);
641 	}
642 	strcpy(saved_command_line + xlen, boot_command_line);
643 	strcpy(static_command_line + xlen, command_line);
644 
645 	if (ilen) {
646 		/*
647 		 * Append supplemental init boot args to saved_command_line
648 		 * so that user can check what command line options passed
649 		 * to init.
650 		 */
651 		len = strlen(saved_command_line);
652 		if (initargs_found) {
653 			saved_command_line[len++] = ' ';
654 		} else {
655 			strcpy(saved_command_line + len, " -- ");
656 			len += 4;
657 		}
658 
659 		strcpy(saved_command_line + len, extra_init_args);
660 	}
661 }
662 
663 /*
664  * We need to finalize in a non-__init function or else race conditions
665  * between the root thread and the init thread may cause start_kernel to
666  * be reaped by free_initmem before the root thread has proceeded to
667  * cpu_idle.
668  *
669  * gcc-3.4 accidentally inlines this function, so use noinline.
670  */
671 
672 static __initdata DECLARE_COMPLETION(kthreadd_done);
673 
674 noinline void __ref rest_init(void)
675 {
676 	struct task_struct *tsk;
677 	int pid;
678 
679 	rcu_scheduler_starting();
680 	/*
681 	 * We need to spawn init first so that it obtains pid 1, however
682 	 * the init task will end up wanting to create kthreads, which, if
683 	 * we schedule it before we create kthreadd, will OOPS.
684 	 */
685 	pid = kernel_thread(kernel_init, NULL, CLONE_FS);
686 	/*
687 	 * Pin init on the boot CPU. Task migration is not properly working
688 	 * until sched_init_smp() has been run. It will set the allowed
689 	 * CPUs for init to the non isolated CPUs.
690 	 */
691 	rcu_read_lock();
692 	tsk = find_task_by_pid_ns(pid, &init_pid_ns);
693 	set_cpus_allowed_ptr(tsk, cpumask_of(smp_processor_id()));
694 	rcu_read_unlock();
695 
696 	numa_default_policy();
697 	pid = kernel_thread(kthreadd, NULL, CLONE_FS | CLONE_FILES);
698 	rcu_read_lock();
699 	kthreadd_task = find_task_by_pid_ns(pid, &init_pid_ns);
700 	rcu_read_unlock();
701 
702 	/*
703 	 * Enable might_sleep() and smp_processor_id() checks.
704 	 * They cannot be enabled earlier because with CONFIG_PREEMPTION=y
705 	 * kernel_thread() would trigger might_sleep() splats. With
706 	 * CONFIG_PREEMPT_VOLUNTARY=y the init task might have scheduled
707 	 * already, but it's stuck on the kthreadd_done completion.
708 	 */
709 	system_state = SYSTEM_SCHEDULING;
710 
711 	complete(&kthreadd_done);
712 
713 	/*
714 	 * The boot idle thread must execute schedule()
715 	 * at least once to get things moving:
716 	 */
717 	schedule_preempt_disabled();
718 	/* Call into cpu_idle with preempt disabled */
719 	cpu_startup_entry(CPUHP_ONLINE);
720 }
721 
722 /* Check for early params. */
723 static int __init do_early_param(char *param, char *val,
724 				 const char *unused, void *arg)
725 {
726 	const struct obs_kernel_param *p;
727 
728 	for (p = __setup_start; p < __setup_end; p++) {
729 		if ((p->early && parameq(param, p->str)) ||
730 		    (strcmp(param, "console") == 0 &&
731 		     strcmp(p->str, "earlycon") == 0)
732 		) {
733 			if (p->setup_func(val) != 0)
734 				pr_warn("Malformed early option '%s'\n", param);
735 		}
736 	}
737 	/* We accept everything at this stage. */
738 	return 0;
739 }
740 
741 void __init parse_early_options(char *cmdline)
742 {
743 	parse_args("early options", cmdline, NULL, 0, 0, 0, NULL,
744 		   do_early_param);
745 }
746 
747 /* Arch code calls this early on, or if not, just before other parsing. */
748 void __init parse_early_param(void)
749 {
750 	static int done __initdata;
751 	static char tmp_cmdline[COMMAND_LINE_SIZE] __initdata;
752 
753 	if (done)
754 		return;
755 
756 	/* All fall through to do_early_param. */
757 	strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);
758 	parse_early_options(tmp_cmdline);
759 	done = 1;
760 }
761 
762 void __init __weak arch_post_acpi_subsys_init(void) { }
763 
764 void __init __weak smp_setup_processor_id(void)
765 {
766 }
767 
768 # if THREAD_SIZE >= PAGE_SIZE
769 void __init __weak thread_stack_cache_init(void)
770 {
771 }
772 #endif
773 
774 void __init __weak mem_encrypt_init(void) { }
775 
776 void __init __weak poking_init(void) { }
777 
778 void __init __weak pgtable_cache_init(void) { }
779 
780 bool initcall_debug;
781 core_param(initcall_debug, initcall_debug, bool, 0644);
782 
783 #ifdef TRACEPOINTS_ENABLED
784 static void __init initcall_debug_enable(void);
785 #else
786 static inline void initcall_debug_enable(void)
787 {
788 }
789 #endif
790 
791 /* Report memory auto-initialization states for this boot. */
792 static void __init report_meminit(void)
793 {
794 	const char *stack;
795 
796 	if (IS_ENABLED(CONFIG_INIT_STACK_ALL_PATTERN))
797 		stack = "all(pattern)";
798 	else if (IS_ENABLED(CONFIG_INIT_STACK_ALL_ZERO))
799 		stack = "all(zero)";
800 	else if (IS_ENABLED(CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL))
801 		stack = "byref_all(zero)";
802 	else if (IS_ENABLED(CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF))
803 		stack = "byref(zero)";
804 	else if (IS_ENABLED(CONFIG_GCC_PLUGIN_STRUCTLEAK_USER))
805 		stack = "__user(zero)";
806 	else
807 		stack = "off";
808 
809 	pr_info("mem auto-init: stack:%s, heap alloc:%s, heap free:%s\n",
810 		stack, want_init_on_alloc(GFP_KERNEL) ? "on" : "off",
811 		want_init_on_free() ? "on" : "off");
812 	if (want_init_on_free())
813 		pr_info("mem auto-init: clearing system memory may take some time...\n");
814 }
815 
816 /*
817  * Set up kernel memory allocators
818  */
819 static void __init mm_init(void)
820 {
821 	/*
822 	 * page_ext requires contiguous pages,
823 	 * bigger than MAX_ORDER unless SPARSEMEM.
824 	 */
825 	page_ext_init_flatmem();
826 	init_mem_debugging_and_hardening();
827 	report_meminit();
828 	mem_init();
829 	/* page_owner must be initialized after buddy is ready */
830 	page_ext_init_flatmem_late();
831 	kmem_cache_init();
832 	kmemleak_init();
833 	pgtable_init();
834 	debug_objects_mem_init();
835 	vmalloc_init();
836 	ioremap_huge_init();
837 	/* Should be run before the first non-init thread is created */
838 	init_espfix_bsp();
839 	/* Should be run after espfix64 is set up. */
840 	pti_init();
841 }
842 
843 void __init __weak arch_call_rest_init(void)
844 {
845 	rest_init();
846 }
847 
848 asmlinkage __visible void __init __no_sanitize_address start_kernel(void)
849 {
850 	char *command_line;
851 	char *after_dashes;
852 
853 	set_task_stack_end_magic(&init_task);
854 	smp_setup_processor_id();
855 	debug_objects_early_init();
856 
857 	cgroup_init_early();
858 
859 	local_irq_disable();
860 	early_boot_irqs_disabled = true;
861 
862 	/*
863 	 * Interrupts are still disabled. Do necessary setups, then
864 	 * enable them.
865 	 */
866 	boot_cpu_init();
867 	page_address_init();
868 	pr_notice("%s", linux_banner);
869 	early_security_init();
870 	setup_arch(&command_line);
871 	setup_boot_config(command_line);
872 	setup_command_line(command_line);
873 	setup_nr_cpu_ids();
874 	setup_per_cpu_areas();
875 	smp_prepare_boot_cpu();	/* arch-specific boot-cpu hooks */
876 	boot_cpu_hotplug_init();
877 
878 	build_all_zonelists(NULL);
879 	page_alloc_init();
880 
881 	pr_notice("Kernel command line: %s\n", saved_command_line);
882 	/* parameters may set static keys */
883 	jump_label_init();
884 	parse_early_param();
885 	after_dashes = parse_args("Booting kernel",
886 				  static_command_line, __start___param,
887 				  __stop___param - __start___param,
888 				  -1, -1, NULL, &unknown_bootoption);
889 	if (!IS_ERR_OR_NULL(after_dashes))
890 		parse_args("Setting init args", after_dashes, NULL, 0, -1, -1,
891 			   NULL, set_init_arg);
892 	if (extra_init_args)
893 		parse_args("Setting extra init args", extra_init_args,
894 			   NULL, 0, -1, -1, NULL, set_init_arg);
895 
896 	/*
897 	 * These use large bootmem allocations and must precede
898 	 * kmem_cache_init()
899 	 */
900 	setup_log_buf(0);
901 	vfs_caches_init_early();
902 	sort_main_extable();
903 	trap_init();
904 	mm_init();
905 
906 	ftrace_init();
907 
908 	/* trace_printk can be enabled here */
909 	early_trace_init();
910 
911 	/*
912 	 * Set up the scheduler prior starting any interrupts (such as the
913 	 * timer interrupt). Full topology setup happens at smp_init()
914 	 * time - but meanwhile we still have a functioning scheduler.
915 	 */
916 	sched_init();
917 	/*
918 	 * Disable preemption - early bootup scheduling is extremely
919 	 * fragile until we cpu_idle() for the first time.
920 	 */
921 	preempt_disable();
922 	if (WARN(!irqs_disabled(),
923 		 "Interrupts were enabled *very* early, fixing it\n"))
924 		local_irq_disable();
925 	radix_tree_init();
926 
927 	/*
928 	 * Set up housekeeping before setting up workqueues to allow the unbound
929 	 * workqueue to take non-housekeeping into account.
930 	 */
931 	housekeeping_init();
932 
933 	/*
934 	 * Allow workqueue creation and work item queueing/cancelling
935 	 * early.  Work item execution depends on kthreads and starts after
936 	 * workqueue_init().
937 	 */
938 	workqueue_init_early();
939 
940 	rcu_init();
941 
942 	/* Trace events are available after this */
943 	trace_init();
944 
945 	if (initcall_debug)
946 		initcall_debug_enable();
947 
948 	context_tracking_init();
949 	/* init some links before init_ISA_irqs() */
950 	early_irq_init();
951 	init_IRQ();
952 	tick_init();
953 	rcu_init_nohz();
954 	init_timers();
955 	hrtimers_init();
956 	softirq_init();
957 	timekeeping_init();
958 
959 	/*
960 	 * For best initial stack canary entropy, prepare it after:
961 	 * - setup_arch() for any UEFI RNG entropy and boot cmdline access
962 	 * - timekeeping_init() for ktime entropy used in rand_initialize()
963 	 * - rand_initialize() to get any arch-specific entropy like RDRAND
964 	 * - add_latent_entropy() to get any latent entropy
965 	 * - adding command line entropy
966 	 */
967 	rand_initialize();
968 	add_latent_entropy();
969 	add_device_randomness(command_line, strlen(command_line));
970 	boot_init_stack_canary();
971 
972 	time_init();
973 	perf_event_init();
974 	profile_init();
975 	call_function_init();
976 	WARN(!irqs_disabled(), "Interrupts were enabled early\n");
977 
978 	early_boot_irqs_disabled = false;
979 	local_irq_enable();
980 
981 	kmem_cache_init_late();
982 
983 	/*
984 	 * HACK ALERT! This is early. We're enabling the console before
985 	 * we've done PCI setups etc, and console_init() must be aware of
986 	 * this. But we do want output early, in case something goes wrong.
987 	 */
988 	console_init();
989 	if (panic_later)
990 		panic("Too many boot %s vars at `%s'", panic_later,
991 		      panic_param);
992 
993 	lockdep_init();
994 
995 	/*
996 	 * Need to run this when irqs are enabled, because it wants
997 	 * to self-test [hard/soft]-irqs on/off lock inversion bugs
998 	 * too:
999 	 */
1000 	locking_selftest();
1001 
1002 	/*
1003 	 * This needs to be called before any devices perform DMA
1004 	 * operations that might use the SWIOTLB bounce buffers. It will
1005 	 * mark the bounce buffers as decrypted so that their usage will
1006 	 * not cause "plain-text" data to be decrypted when accessed.
1007 	 */
1008 	mem_encrypt_init();
1009 
1010 #ifdef CONFIG_BLK_DEV_INITRD
1011 	if (initrd_start && !initrd_below_start_ok &&
1012 	    page_to_pfn(virt_to_page((void *)initrd_start)) < min_low_pfn) {
1013 		pr_crit("initrd overwritten (0x%08lx < 0x%08lx) - disabling it.\n",
1014 		    page_to_pfn(virt_to_page((void *)initrd_start)),
1015 		    min_low_pfn);
1016 		initrd_start = 0;
1017 	}
1018 #endif
1019 	setup_per_cpu_pageset();
1020 	numa_policy_init();
1021 	acpi_early_init();
1022 	if (late_time_init)
1023 		late_time_init();
1024 	sched_clock_init();
1025 	calibrate_delay();
1026 	pid_idr_init();
1027 	anon_vma_init();
1028 #ifdef CONFIG_X86
1029 	if (efi_enabled(EFI_RUNTIME_SERVICES))
1030 		efi_enter_virtual_mode();
1031 #endif
1032 	thread_stack_cache_init();
1033 	cred_init();
1034 	fork_init();
1035 	proc_caches_init();
1036 	uts_ns_init();
1037 	key_init();
1038 	security_init();
1039 	dbg_late_init();
1040 	vfs_caches_init();
1041 	pagecache_init();
1042 	signals_init();
1043 	seq_file_init();
1044 	proc_root_init();
1045 	nsfs_init();
1046 	cpuset_init();
1047 	cgroup_init();
1048 	taskstats_init_early();
1049 	delayacct_init();
1050 
1051 	poking_init();
1052 	check_bugs();
1053 
1054 	acpi_subsystem_init();
1055 	arch_post_acpi_subsys_init();
1056 	kcsan_init();
1057 
1058 	/* Do the rest non-__init'ed, we're now alive */
1059 	arch_call_rest_init();
1060 
1061 	prevent_tail_call_optimization();
1062 }
1063 
1064 /* Call all constructor functions linked into the kernel. */
1065 static void __init do_ctors(void)
1066 {
1067 /*
1068  * For UML, the constructors have already been called by the
1069  * normal setup code as it's just a normal ELF binary, so we
1070  * cannot do it again - but we do need CONFIG_CONSTRUCTORS
1071  * even on UML for modules.
1072  */
1073 #if defined(CONFIG_CONSTRUCTORS) && !defined(CONFIG_UML)
1074 	ctor_fn_t *fn = (ctor_fn_t *) __ctors_start;
1075 
1076 	for (; fn < (ctor_fn_t *) __ctors_end; fn++)
1077 		(*fn)();
1078 #endif
1079 }
1080 
1081 #ifdef CONFIG_KALLSYMS
1082 struct blacklist_entry {
1083 	struct list_head next;
1084 	char *buf;
1085 };
1086 
1087 static __initdata_or_module LIST_HEAD(blacklisted_initcalls);
1088 
1089 static int __init initcall_blacklist(char *str)
1090 {
1091 	char *str_entry;
1092 	struct blacklist_entry *entry;
1093 
1094 	/* str argument is a comma-separated list of functions */
1095 	do {
1096 		str_entry = strsep(&str, ",");
1097 		if (str_entry) {
1098 			pr_debug("blacklisting initcall %s\n", str_entry);
1099 			entry = memblock_alloc(sizeof(*entry),
1100 					       SMP_CACHE_BYTES);
1101 			if (!entry)
1102 				panic("%s: Failed to allocate %zu bytes\n",
1103 				      __func__, sizeof(*entry));
1104 			entry->buf = memblock_alloc(strlen(str_entry) + 1,
1105 						    SMP_CACHE_BYTES);
1106 			if (!entry->buf)
1107 				panic("%s: Failed to allocate %zu bytes\n",
1108 				      __func__, strlen(str_entry) + 1);
1109 			strcpy(entry->buf, str_entry);
1110 			list_add(&entry->next, &blacklisted_initcalls);
1111 		}
1112 	} while (str_entry);
1113 
1114 	return 0;
1115 }
1116 
1117 static bool __init_or_module initcall_blacklisted(initcall_t fn)
1118 {
1119 	struct blacklist_entry *entry;
1120 	char fn_name[KSYM_SYMBOL_LEN];
1121 	unsigned long addr;
1122 
1123 	if (list_empty(&blacklisted_initcalls))
1124 		return false;
1125 
1126 	addr = (unsigned long) dereference_function_descriptor(fn);
1127 	sprint_symbol_no_offset(fn_name, addr);
1128 
1129 	/*
1130 	 * fn will be "function_name [module_name]" where [module_name] is not
1131 	 * displayed for built-in init functions.  Strip off the [module_name].
1132 	 */
1133 	strreplace(fn_name, ' ', '\0');
1134 
1135 	list_for_each_entry(entry, &blacklisted_initcalls, next) {
1136 		if (!strcmp(fn_name, entry->buf)) {
1137 			pr_debug("initcall %s blacklisted\n", fn_name);
1138 			return true;
1139 		}
1140 	}
1141 
1142 	return false;
1143 }
1144 #else
1145 static int __init initcall_blacklist(char *str)
1146 {
1147 	pr_warn("initcall_blacklist requires CONFIG_KALLSYMS\n");
1148 	return 0;
1149 }
1150 
1151 static bool __init_or_module initcall_blacklisted(initcall_t fn)
1152 {
1153 	return false;
1154 }
1155 #endif
1156 __setup("initcall_blacklist=", initcall_blacklist);
1157 
1158 static __init_or_module void
1159 trace_initcall_start_cb(void *data, initcall_t fn)
1160 {
1161 	ktime_t *calltime = (ktime_t *)data;
1162 
1163 	printk(KERN_DEBUG "calling  %pS @ %i\n", fn, task_pid_nr(current));
1164 	*calltime = ktime_get();
1165 }
1166 
1167 static __init_or_module void
1168 trace_initcall_finish_cb(void *data, initcall_t fn, int ret)
1169 {
1170 	ktime_t *calltime = (ktime_t *)data;
1171 	ktime_t delta, rettime;
1172 	unsigned long long duration;
1173 
1174 	rettime = ktime_get();
1175 	delta = ktime_sub(rettime, *calltime);
1176 	duration = (unsigned long long) ktime_to_ns(delta) >> 10;
1177 	printk(KERN_DEBUG "initcall %pS returned %d after %lld usecs\n",
1178 		 fn, ret, duration);
1179 }
1180 
1181 static ktime_t initcall_calltime;
1182 
1183 #ifdef TRACEPOINTS_ENABLED
1184 static void __init initcall_debug_enable(void)
1185 {
1186 	int ret;
1187 
1188 	ret = register_trace_initcall_start(trace_initcall_start_cb,
1189 					    &initcall_calltime);
1190 	ret |= register_trace_initcall_finish(trace_initcall_finish_cb,
1191 					      &initcall_calltime);
1192 	WARN(ret, "Failed to register initcall tracepoints\n");
1193 }
1194 # define do_trace_initcall_start	trace_initcall_start
1195 # define do_trace_initcall_finish	trace_initcall_finish
1196 #else
1197 static inline void do_trace_initcall_start(initcall_t fn)
1198 {
1199 	if (!initcall_debug)
1200 		return;
1201 	trace_initcall_start_cb(&initcall_calltime, fn);
1202 }
1203 static inline void do_trace_initcall_finish(initcall_t fn, int ret)
1204 {
1205 	if (!initcall_debug)
1206 		return;
1207 	trace_initcall_finish_cb(&initcall_calltime, fn, ret);
1208 }
1209 #endif /* !TRACEPOINTS_ENABLED */
1210 
1211 int __init_or_module do_one_initcall(initcall_t fn)
1212 {
1213 	int count = preempt_count();
1214 	char msgbuf[64];
1215 	int ret;
1216 
1217 	if (initcall_blacklisted(fn))
1218 		return -EPERM;
1219 
1220 	do_trace_initcall_start(fn);
1221 	ret = fn();
1222 	do_trace_initcall_finish(fn, ret);
1223 
1224 	msgbuf[0] = 0;
1225 
1226 	if (preempt_count() != count) {
1227 		sprintf(msgbuf, "preemption imbalance ");
1228 		preempt_count_set(count);
1229 	}
1230 	if (irqs_disabled()) {
1231 		strlcat(msgbuf, "disabled interrupts ", sizeof(msgbuf));
1232 		local_irq_enable();
1233 	}
1234 	WARN(msgbuf[0], "initcall %pS returned with %s\n", fn, msgbuf);
1235 
1236 	add_latent_entropy();
1237 	return ret;
1238 }
1239 
1240 
1241 extern initcall_entry_t __initcall_start[];
1242 extern initcall_entry_t __initcall0_start[];
1243 extern initcall_entry_t __initcall1_start[];
1244 extern initcall_entry_t __initcall2_start[];
1245 extern initcall_entry_t __initcall3_start[];
1246 extern initcall_entry_t __initcall4_start[];
1247 extern initcall_entry_t __initcall5_start[];
1248 extern initcall_entry_t __initcall6_start[];
1249 extern initcall_entry_t __initcall7_start[];
1250 extern initcall_entry_t __initcall_end[];
1251 
1252 static initcall_entry_t *initcall_levels[] __initdata = {
1253 	__initcall0_start,
1254 	__initcall1_start,
1255 	__initcall2_start,
1256 	__initcall3_start,
1257 	__initcall4_start,
1258 	__initcall5_start,
1259 	__initcall6_start,
1260 	__initcall7_start,
1261 	__initcall_end,
1262 };
1263 
1264 /* Keep these in sync with initcalls in include/linux/init.h */
1265 static const char *initcall_level_names[] __initdata = {
1266 	"pure",
1267 	"core",
1268 	"postcore",
1269 	"arch",
1270 	"subsys",
1271 	"fs",
1272 	"device",
1273 	"late",
1274 };
1275 
1276 static int __init ignore_unknown_bootoption(char *param, char *val,
1277 			       const char *unused, void *arg)
1278 {
1279 	return 0;
1280 }
1281 
1282 static void __init do_initcall_level(int level, char *command_line)
1283 {
1284 	initcall_entry_t *fn;
1285 
1286 	parse_args(initcall_level_names[level],
1287 		   command_line, __start___param,
1288 		   __stop___param - __start___param,
1289 		   level, level,
1290 		   NULL, ignore_unknown_bootoption);
1291 
1292 	trace_initcall_level(initcall_level_names[level]);
1293 	for (fn = initcall_levels[level]; fn < initcall_levels[level+1]; fn++)
1294 		do_one_initcall(initcall_from_entry(fn));
1295 }
1296 
1297 static void __init do_initcalls(void)
1298 {
1299 	int level;
1300 	size_t len = strlen(saved_command_line) + 1;
1301 	char *command_line;
1302 
1303 	command_line = kzalloc(len, GFP_KERNEL);
1304 	if (!command_line)
1305 		panic("%s: Failed to allocate %zu bytes\n", __func__, len);
1306 
1307 	for (level = 0; level < ARRAY_SIZE(initcall_levels) - 1; level++) {
1308 		/* Parser modifies command_line, restore it each time */
1309 		strcpy(command_line, saved_command_line);
1310 		do_initcall_level(level, command_line);
1311 	}
1312 
1313 	kfree(command_line);
1314 }
1315 
1316 /*
1317  * Ok, the machine is now initialized. None of the devices
1318  * have been touched yet, but the CPU subsystem is up and
1319  * running, and memory and process management works.
1320  *
1321  * Now we can finally start doing some real work..
1322  */
1323 static void __init do_basic_setup(void)
1324 {
1325 	cpuset_init_smp();
1326 	driver_init();
1327 	init_irq_proc();
1328 	do_ctors();
1329 	usermodehelper_enable();
1330 	do_initcalls();
1331 }
1332 
1333 static void __init do_pre_smp_initcalls(void)
1334 {
1335 	initcall_entry_t *fn;
1336 
1337 	trace_initcall_level("early");
1338 	for (fn = __initcall_start; fn < __initcall0_start; fn++)
1339 		do_one_initcall(initcall_from_entry(fn));
1340 }
1341 
1342 static int run_init_process(const char *init_filename)
1343 {
1344 	const char *const *p;
1345 
1346 	argv_init[0] = init_filename;
1347 	pr_info("Run %s as init process\n", init_filename);
1348 	pr_debug("  with arguments:\n");
1349 	for (p = argv_init; *p; p++)
1350 		pr_debug("    %s\n", *p);
1351 	pr_debug("  with environment:\n");
1352 	for (p = envp_init; *p; p++)
1353 		pr_debug("    %s\n", *p);
1354 	return kernel_execve(init_filename, argv_init, envp_init);
1355 }
1356 
1357 static int try_to_run_init_process(const char *init_filename)
1358 {
1359 	int ret;
1360 
1361 	ret = run_init_process(init_filename);
1362 
1363 	if (ret && ret != -ENOENT) {
1364 		pr_err("Starting init: %s exists but couldn't execute it (error %d)\n",
1365 		       init_filename, ret);
1366 	}
1367 
1368 	return ret;
1369 }
1370 
1371 static noinline void __init kernel_init_freeable(void);
1372 
1373 #if defined(CONFIG_STRICT_KERNEL_RWX) || defined(CONFIG_STRICT_MODULE_RWX)
1374 bool rodata_enabled __ro_after_init = true;
1375 static int __init set_debug_rodata(char *str)
1376 {
1377 	return strtobool(str, &rodata_enabled);
1378 }
1379 __setup("rodata=", set_debug_rodata);
1380 #endif
1381 
1382 #ifdef CONFIG_STRICT_KERNEL_RWX
1383 static void mark_readonly(void)
1384 {
1385 	if (rodata_enabled) {
1386 		/*
1387 		 * load_module() results in W+X mappings, which are cleaned
1388 		 * up with call_rcu().  Let's make sure that queued work is
1389 		 * flushed so that we don't hit false positives looking for
1390 		 * insecure pages which are W+X.
1391 		 */
1392 		rcu_barrier();
1393 		mark_rodata_ro();
1394 		rodata_test();
1395 	} else
1396 		pr_info("Kernel memory protection disabled.\n");
1397 }
1398 #elif defined(CONFIG_ARCH_HAS_STRICT_KERNEL_RWX)
1399 static inline void mark_readonly(void)
1400 {
1401 	pr_warn("Kernel memory protection not selected by kernel config.\n");
1402 }
1403 #else
1404 static inline void mark_readonly(void)
1405 {
1406 	pr_warn("This architecture does not have kernel memory protection.\n");
1407 }
1408 #endif
1409 
1410 void __weak free_initmem(void)
1411 {
1412 	free_initmem_default(POISON_FREE_INITMEM);
1413 }
1414 
1415 static int __ref kernel_init(void *unused)
1416 {
1417 	int ret;
1418 
1419 	kernel_init_freeable();
1420 	/* need to finish all async __init code before freeing the memory */
1421 	async_synchronize_full();
1422 	kprobe_free_init_mem();
1423 	ftrace_free_init_mem();
1424 	free_initmem();
1425 	mark_readonly();
1426 
1427 	/*
1428 	 * Kernel mappings are now finalized - update the userspace page-table
1429 	 * to finalize PTI.
1430 	 */
1431 	pti_finalize();
1432 
1433 	system_state = SYSTEM_RUNNING;
1434 	numa_default_policy();
1435 
1436 	rcu_end_inkernel_boot();
1437 
1438 	do_sysctl_args();
1439 
1440 	if (ramdisk_execute_command) {
1441 		ret = run_init_process(ramdisk_execute_command);
1442 		if (!ret)
1443 			return 0;
1444 		pr_err("Failed to execute %s (error %d)\n",
1445 		       ramdisk_execute_command, ret);
1446 	}
1447 
1448 	/*
1449 	 * We try each of these until one succeeds.
1450 	 *
1451 	 * The Bourne shell can be used instead of init if we are
1452 	 * trying to recover a really broken machine.
1453 	 */
1454 	if (execute_command) {
1455 		ret = run_init_process(execute_command);
1456 		if (!ret)
1457 			return 0;
1458 		panic("Requested init %s failed (error %d).",
1459 		      execute_command, ret);
1460 	}
1461 
1462 	if (CONFIG_DEFAULT_INIT[0] != '\0') {
1463 		ret = run_init_process(CONFIG_DEFAULT_INIT);
1464 		if (ret)
1465 			pr_err("Default init %s failed (error %d)\n",
1466 			       CONFIG_DEFAULT_INIT, ret);
1467 		else
1468 			return 0;
1469 	}
1470 
1471 	if (!try_to_run_init_process("/sbin/init") ||
1472 	    !try_to_run_init_process("/etc/init") ||
1473 	    !try_to_run_init_process("/bin/init") ||
1474 	    !try_to_run_init_process("/bin/sh"))
1475 		return 0;
1476 
1477 	panic("No working init found.  Try passing init= option to kernel. "
1478 	      "See Linux Documentation/admin-guide/init.rst for guidance.");
1479 }
1480 
1481 /* Open /dev/console, for stdin/stdout/stderr, this should never fail */
1482 void __init console_on_rootfs(void)
1483 {
1484 	struct file *file = filp_open("/dev/console", O_RDWR, 0);
1485 
1486 	if (IS_ERR(file)) {
1487 		pr_err("Warning: unable to open an initial console.\n");
1488 		return;
1489 	}
1490 	init_dup(file);
1491 	init_dup(file);
1492 	init_dup(file);
1493 	fput(file);
1494 }
1495 
1496 static noinline void __init kernel_init_freeable(void)
1497 {
1498 	/*
1499 	 * Wait until kthreadd is all set-up.
1500 	 */
1501 	wait_for_completion(&kthreadd_done);
1502 
1503 	/* Now the scheduler is fully set up and can do blocking allocations */
1504 	gfp_allowed_mask = __GFP_BITS_MASK;
1505 
1506 	/*
1507 	 * init can allocate pages on any node
1508 	 */
1509 	set_mems_allowed(node_states[N_MEMORY]);
1510 
1511 	cad_pid = task_pid(current);
1512 
1513 	smp_prepare_cpus(setup_max_cpus);
1514 
1515 	workqueue_init();
1516 
1517 	init_mm_internals();
1518 
1519 	rcu_init_tasks_generic();
1520 	do_pre_smp_initcalls();
1521 	lockup_detector_init();
1522 
1523 	smp_init();
1524 	sched_init_smp();
1525 
1526 	padata_init();
1527 	page_alloc_init_late();
1528 	/* Initialize page ext after all struct pages are initialized. */
1529 	page_ext_init();
1530 
1531 	do_basic_setup();
1532 
1533 	kunit_run_all_tests();
1534 
1535 	console_on_rootfs();
1536 
1537 	/*
1538 	 * check if there is an early userspace init.  If yes, let it do all
1539 	 * the work
1540 	 */
1541 	if (init_eaccess(ramdisk_execute_command) != 0) {
1542 		ramdisk_execute_command = NULL;
1543 		prepare_namespace();
1544 	}
1545 
1546 	/*
1547 	 * Ok, we have completed the initial bootup, and
1548 	 * we're essentially up and running. Get rid of the
1549 	 * initmem segments and start the user-mode stuff..
1550 	 *
1551 	 * rootfs is available now, try loading the public keys
1552 	 * and default modules
1553 	 */
1554 
1555 	integrity_load_keys();
1556 }
1557