xref: /openbmc/linux/init/main.c (revision 36fe4655)
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/sfi.h>
78 #include <linux/shmem_fs.h>
79 #include <linux/slab.h>
80 #include <linux/perf_event.h>
81 #include <linux/ptrace.h>
82 #include <linux/pti.h>
83 #include <linux/blkdev.h>
84 #include <linux/elevator.h>
85 #include <linux/sched/clock.h>
86 #include <linux/sched/task.h>
87 #include <linux/sched/task_stack.h>
88 #include <linux/context_tracking.h>
89 #include <linux/random.h>
90 #include <linux/list.h>
91 #include <linux/integrity.h>
92 #include <linux/proc_ns.h>
93 #include <linux/io.h>
94 #include <linux/cache.h>
95 #include <linux/rodata_test.h>
96 #include <linux/jump_label.h>
97 #include <linux/mem_encrypt.h>
98 #include <linux/kcsan.h>
99 #include <linux/init_syscalls.h>
100 
101 #include <asm/io.h>
102 #include <asm/bugs.h>
103 #include <asm/setup.h>
104 #include <asm/sections.h>
105 #include <asm/cacheflush.h>
106 
107 #define CREATE_TRACE_POINTS
108 #include <trace/events/initcall.h>
109 
110 #include <kunit/test.h>
111 
112 static int kernel_init(void *);
113 
114 extern void init_IRQ(void);
115 extern void radix_tree_init(void);
116 
117 /*
118  * Debug helper: via this flag we know that we are in 'early bootup code'
119  * where only the boot processor is running with IRQ disabled.  This means
120  * two things - IRQ must not be enabled before the flag is cleared and some
121  * operations which are not allowed with IRQ disabled are allowed while the
122  * flag is set.
123  */
124 bool early_boot_irqs_disabled __read_mostly;
125 
126 enum system_states system_state __read_mostly;
127 EXPORT_SYMBOL(system_state);
128 
129 /*
130  * Boot command-line arguments
131  */
132 #define MAX_INIT_ARGS CONFIG_INIT_ENV_ARG_LIMIT
133 #define MAX_INIT_ENVS CONFIG_INIT_ENV_ARG_LIMIT
134 
135 extern void time_init(void);
136 /* Default late time init is NULL. archs can override this later. */
137 void (*__initdata late_time_init)(void);
138 
139 /* Untouched command line saved by arch-specific code. */
140 char __initdata boot_command_line[COMMAND_LINE_SIZE];
141 /* Untouched saved command line (eg. for /proc) */
142 char *saved_command_line;
143 /* Command line for parameter parsing */
144 static char *static_command_line;
145 /* Untouched extra command line */
146 static char *extra_command_line;
147 /* Extra init arguments */
148 static char *extra_init_args;
149 
150 #ifdef CONFIG_BOOT_CONFIG
151 /* Is bootconfig on command line? */
152 static bool bootconfig_found;
153 static bool initargs_found;
154 #else
155 # define bootconfig_found false
156 # define initargs_found false
157 #endif
158 
159 static char *execute_command;
160 static char *ramdisk_execute_command = "/init";
161 
162 /*
163  * Used to generate warnings if static_key manipulation functions are used
164  * before jump_label_init is called.
165  */
166 bool static_key_initialized __read_mostly;
167 EXPORT_SYMBOL_GPL(static_key_initialized);
168 
169 /*
170  * If set, this is an indication to the drivers that reset the underlying
171  * device before going ahead with the initialization otherwise driver might
172  * rely on the BIOS and skip the reset operation.
173  *
174  * This is useful if kernel is booting in an unreliable environment.
175  * For ex. kdump situation where previous kernel has crashed, BIOS has been
176  * skipped and devices will be in unknown state.
177  */
178 unsigned int reset_devices;
179 EXPORT_SYMBOL(reset_devices);
180 
181 static int __init set_reset_devices(char *str)
182 {
183 	reset_devices = 1;
184 	return 1;
185 }
186 
187 __setup("reset_devices", set_reset_devices);
188 
189 static const char *argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
190 const char *envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, };
191 static const char *panic_later, *panic_param;
192 
193 extern const struct obs_kernel_param __setup_start[], __setup_end[];
194 
195 static bool __init obsolete_checksetup(char *line)
196 {
197 	const struct obs_kernel_param *p;
198 	bool had_early_param = false;
199 
200 	p = __setup_start;
201 	do {
202 		int n = strlen(p->str);
203 		if (parameqn(line, p->str, n)) {
204 			if (p->early) {
205 				/* Already done in parse_early_param?
206 				 * (Needs exact match on param part).
207 				 * Keep iterating, as we can have early
208 				 * params and __setups of same names 8( */
209 				if (line[n] == '\0' || line[n] == '=')
210 					had_early_param = true;
211 			} else if (!p->setup_func) {
212 				pr_warn("Parameter %s is obsolete, ignored\n",
213 					p->str);
214 				return true;
215 			} else if (p->setup_func(line + n))
216 				return true;
217 		}
218 		p++;
219 	} while (p < __setup_end);
220 
221 	return had_early_param;
222 }
223 
224 /*
225  * This should be approx 2 Bo*oMips to start (note initial shift), and will
226  * still work even if initially too large, it will just take slightly longer
227  */
228 unsigned long loops_per_jiffy = (1<<12);
229 EXPORT_SYMBOL(loops_per_jiffy);
230 
231 static int __init debug_kernel(char *str)
232 {
233 	console_loglevel = CONSOLE_LOGLEVEL_DEBUG;
234 	return 0;
235 }
236 
237 static int __init quiet_kernel(char *str)
238 {
239 	console_loglevel = CONSOLE_LOGLEVEL_QUIET;
240 	return 0;
241 }
242 
243 early_param("debug", debug_kernel);
244 early_param("quiet", quiet_kernel);
245 
246 static int __init loglevel(char *str)
247 {
248 	int newlevel;
249 
250 	/*
251 	 * Only update loglevel value when a correct setting was passed,
252 	 * to prevent blind crashes (when loglevel being set to 0) that
253 	 * are quite hard to debug
254 	 */
255 	if (get_option(&str, &newlevel)) {
256 		console_loglevel = newlevel;
257 		return 0;
258 	}
259 
260 	return -EINVAL;
261 }
262 
263 early_param("loglevel", loglevel);
264 
265 #ifdef CONFIG_BLK_DEV_INITRD
266 static void * __init get_boot_config_from_initrd(u32 *_size, u32 *_csum)
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 	/* Remove bootconfig from initramfs/initrd */
301 	initrd_end = (unsigned long)data;
302 	if (_size)
303 		*_size = size;
304 	if (_csum)
305 		*_csum = csum;
306 
307 	return data;
308 }
309 #else
310 static void * __init get_boot_config_from_initrd(u32 *_size, u32 *_csum)
311 {
312 	return NULL;
313 }
314 #endif
315 
316 #ifdef CONFIG_BOOT_CONFIG
317 
318 static char xbc_namebuf[XBC_KEYLEN_MAX] __initdata;
319 
320 #define rest(dst, end) ((end) > (dst) ? (end) - (dst) : 0)
321 
322 static int __init xbc_snprint_cmdline(char *buf, size_t size,
323 				      struct xbc_node *root)
324 {
325 	struct xbc_node *knode, *vnode;
326 	char *end = buf + size;
327 	const char *val;
328 	int ret;
329 
330 	xbc_node_for_each_key_value(root, knode, val) {
331 		ret = xbc_node_compose_key_after(root, knode,
332 					xbc_namebuf, XBC_KEYLEN_MAX);
333 		if (ret < 0)
334 			return ret;
335 
336 		vnode = xbc_node_get_child(knode);
337 		if (!vnode) {
338 			ret = snprintf(buf, rest(buf, end), "%s ", xbc_namebuf);
339 			if (ret < 0)
340 				return ret;
341 			buf += ret;
342 			continue;
343 		}
344 		xbc_array_for_each_value(vnode, val) {
345 			ret = snprintf(buf, rest(buf, end), "%s=\"%s\" ",
346 				       xbc_namebuf, val);
347 			if (ret < 0)
348 				return ret;
349 			buf += ret;
350 		}
351 	}
352 
353 	return buf - (end - size);
354 }
355 #undef rest
356 
357 /* Make an extra command line under given key word */
358 static char * __init xbc_make_cmdline(const char *key)
359 {
360 	struct xbc_node *root;
361 	char *new_cmdline;
362 	int ret, len = 0;
363 
364 	root = xbc_find_node(key);
365 	if (!root)
366 		return NULL;
367 
368 	/* Count required buffer size */
369 	len = xbc_snprint_cmdline(NULL, 0, root);
370 	if (len <= 0)
371 		return NULL;
372 
373 	new_cmdline = memblock_alloc(len + 1, SMP_CACHE_BYTES);
374 	if (!new_cmdline) {
375 		pr_err("Failed to allocate memory for extra kernel cmdline.\n");
376 		return NULL;
377 	}
378 
379 	ret = xbc_snprint_cmdline(new_cmdline, len + 1, root);
380 	if (ret < 0 || ret > len) {
381 		pr_err("Failed to print extra kernel cmdline.\n");
382 		return NULL;
383 	}
384 
385 	return new_cmdline;
386 }
387 
388 static u32 boot_config_checksum(unsigned char *p, u32 size)
389 {
390 	u32 ret = 0;
391 
392 	while (size--)
393 		ret += *p++;
394 
395 	return ret;
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 void __init setup_boot_config(const char *cmdline)
408 {
409 	static char tmp_cmdline[COMMAND_LINE_SIZE] __initdata;
410 	const char *msg;
411 	int pos;
412 	u32 size, csum;
413 	char *data, *copy, *err;
414 	int ret;
415 
416 	/* Cut out the bootconfig data even if we have no bootconfig option */
417 	data = get_boot_config_from_initrd(&size, &csum);
418 
419 	strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);
420 	err = parse_args("bootconfig", tmp_cmdline, NULL, 0, 0, 0, NULL,
421 			 bootconfig_params);
422 
423 	if (IS_ERR(err) || !bootconfig_found)
424 		return;
425 
426 	/* parse_args() stops at '--' and returns an address */
427 	if (err)
428 		initargs_found = true;
429 
430 	if (!data) {
431 		pr_err("'bootconfig' found on command line, but no bootconfig found\n");
432 		return;
433 	}
434 
435 	if (size >= XBC_DATA_MAX) {
436 		pr_err("bootconfig size %d greater than max size %d\n",
437 			size, XBC_DATA_MAX);
438 		return;
439 	}
440 
441 	if (boot_config_checksum((unsigned char *)data, size) != csum) {
442 		pr_err("bootconfig checksum failed\n");
443 		return;
444 	}
445 
446 	copy = memblock_alloc(size + 1, SMP_CACHE_BYTES);
447 	if (!copy) {
448 		pr_err("Failed to allocate memory for bootconfig\n");
449 		return;
450 	}
451 
452 	memcpy(copy, data, size);
453 	copy[size] = '\0';
454 
455 	ret = xbc_init(copy, &msg, &pos);
456 	if (ret < 0) {
457 		if (pos < 0)
458 			pr_err("Failed to init bootconfig: %s.\n", msg);
459 		else
460 			pr_err("Failed to parse bootconfig: %s at %d.\n",
461 				msg, pos);
462 	} else {
463 		pr_info("Load bootconfig: %d bytes %d nodes\n", size, ret);
464 		/* keys starting with "kernel." are passed via cmdline */
465 		extra_command_line = xbc_make_cmdline("kernel");
466 		/* Also, "init." keys are init arguments */
467 		extra_init_args = xbc_make_cmdline("init");
468 	}
469 	return;
470 }
471 
472 #else
473 
474 static void __init setup_boot_config(const char *cmdline)
475 {
476 	/* Remove bootconfig data from initrd */
477 	get_boot_config_from_initrd(NULL, NULL);
478 }
479 
480 static int __init warn_bootconfig(char *str)
481 {
482 	pr_warn("WARNING: 'bootconfig' found on the kernel command line but CONFIG_BOOT_CONFIG is not set.\n");
483 	return 0;
484 }
485 early_param("bootconfig", warn_bootconfig);
486 
487 #endif
488 
489 /* Change NUL term back to "=", to make "param" the whole string. */
490 static void __init repair_env_string(char *param, char *val)
491 {
492 	if (val) {
493 		/* param=val or param="val"? */
494 		if (val == param+strlen(param)+1)
495 			val[-1] = '=';
496 		else if (val == param+strlen(param)+2) {
497 			val[-2] = '=';
498 			memmove(val-1, val, strlen(val)+1);
499 		} else
500 			BUG();
501 	}
502 }
503 
504 /* Anything after -- gets handed straight to init. */
505 static int __init set_init_arg(char *param, char *val,
506 			       const char *unused, void *arg)
507 {
508 	unsigned int i;
509 
510 	if (panic_later)
511 		return 0;
512 
513 	repair_env_string(param, val);
514 
515 	for (i = 0; argv_init[i]; i++) {
516 		if (i == MAX_INIT_ARGS) {
517 			panic_later = "init";
518 			panic_param = param;
519 			return 0;
520 		}
521 	}
522 	argv_init[i] = param;
523 	return 0;
524 }
525 
526 /*
527  * Unknown boot options get handed to init, unless they look like
528  * unused parameters (modprobe will find them in /proc/cmdline).
529  */
530 static int __init unknown_bootoption(char *param, char *val,
531 				     const char *unused, void *arg)
532 {
533 	size_t len = strlen(param);
534 
535 	repair_env_string(param, val);
536 
537 	/* Handle obsolete-style parameters */
538 	if (obsolete_checksetup(param))
539 		return 0;
540 
541 	/* Unused module parameter. */
542 	if (strnchr(param, len, '.'))
543 		return 0;
544 
545 	if (panic_later)
546 		return 0;
547 
548 	if (val) {
549 		/* Environment option */
550 		unsigned int i;
551 		for (i = 0; envp_init[i]; i++) {
552 			if (i == MAX_INIT_ENVS) {
553 				panic_later = "env";
554 				panic_param = param;
555 			}
556 			if (!strncmp(param, envp_init[i], len+1))
557 				break;
558 		}
559 		envp_init[i] = param;
560 	} else {
561 		/* Command line option */
562 		unsigned int i;
563 		for (i = 0; argv_init[i]; i++) {
564 			if (i == MAX_INIT_ARGS) {
565 				panic_later = "init";
566 				panic_param = param;
567 			}
568 		}
569 		argv_init[i] = param;
570 	}
571 	return 0;
572 }
573 
574 static int __init init_setup(char *str)
575 {
576 	unsigned int i;
577 
578 	execute_command = str;
579 	/*
580 	 * In case LILO is going to boot us with default command line,
581 	 * it prepends "auto" before the whole cmdline which makes
582 	 * the shell think it should execute a script with such name.
583 	 * So we ignore all arguments entered _before_ init=... [MJ]
584 	 */
585 	for (i = 1; i < MAX_INIT_ARGS; i++)
586 		argv_init[i] = NULL;
587 	return 1;
588 }
589 __setup("init=", init_setup);
590 
591 static int __init rdinit_setup(char *str)
592 {
593 	unsigned int i;
594 
595 	ramdisk_execute_command = str;
596 	/* See "auto" comment in init_setup */
597 	for (i = 1; i < MAX_INIT_ARGS; i++)
598 		argv_init[i] = NULL;
599 	return 1;
600 }
601 __setup("rdinit=", rdinit_setup);
602 
603 #ifndef CONFIG_SMP
604 static const unsigned int setup_max_cpus = NR_CPUS;
605 static inline void setup_nr_cpu_ids(void) { }
606 static inline void smp_prepare_cpus(unsigned int maxcpus) { }
607 #endif
608 
609 /*
610  * We need to store the untouched command line for future reference.
611  * We also need to store the touched command line since the parameter
612  * parsing is performed in place, and we should allow a component to
613  * store reference of name/value for future reference.
614  */
615 static void __init setup_command_line(char *command_line)
616 {
617 	size_t len, xlen = 0, ilen = 0;
618 
619 	if (extra_command_line)
620 		xlen = strlen(extra_command_line);
621 	if (extra_init_args)
622 		ilen = strlen(extra_init_args) + 4; /* for " -- " */
623 
624 	len = xlen + strlen(boot_command_line) + 1;
625 
626 	saved_command_line = memblock_alloc(len + ilen, SMP_CACHE_BYTES);
627 	if (!saved_command_line)
628 		panic("%s: Failed to allocate %zu bytes\n", __func__, len + ilen);
629 
630 	static_command_line = memblock_alloc(len, SMP_CACHE_BYTES);
631 	if (!static_command_line)
632 		panic("%s: Failed to allocate %zu bytes\n", __func__, len);
633 
634 	if (xlen) {
635 		/*
636 		 * We have to put extra_command_line before boot command
637 		 * lines because there could be dashes (separator of init
638 		 * command line) in the command lines.
639 		 */
640 		strcpy(saved_command_line, extra_command_line);
641 		strcpy(static_command_line, extra_command_line);
642 	}
643 	strcpy(saved_command_line + xlen, boot_command_line);
644 	strcpy(static_command_line + xlen, command_line);
645 
646 	if (ilen) {
647 		/*
648 		 * Append supplemental init boot args to saved_command_line
649 		 * so that user can check what command line options passed
650 		 * to init.
651 		 */
652 		len = strlen(saved_command_line);
653 		if (initargs_found) {
654 			saved_command_line[len++] = ' ';
655 		} else {
656 			strcpy(saved_command_line + len, " -- ");
657 			len += 4;
658 		}
659 
660 		strcpy(saved_command_line + len, extra_init_args);
661 	}
662 }
663 
664 /*
665  * We need to finalize in a non-__init function or else race conditions
666  * between the root thread and the init thread may cause start_kernel to
667  * be reaped by free_initmem before the root thread has proceeded to
668  * cpu_idle.
669  *
670  * gcc-3.4 accidentally inlines this function, so use noinline.
671  */
672 
673 static __initdata DECLARE_COMPLETION(kthreadd_done);
674 
675 noinline void __ref rest_init(void)
676 {
677 	struct task_struct *tsk;
678 	int pid;
679 
680 	rcu_scheduler_starting();
681 	/*
682 	 * We need to spawn init first so that it obtains pid 1, however
683 	 * the init task will end up wanting to create kthreads, which, if
684 	 * we schedule it before we create kthreadd, will OOPS.
685 	 */
686 	pid = kernel_thread(kernel_init, NULL, CLONE_FS);
687 	/*
688 	 * Pin init on the boot CPU. Task migration is not properly working
689 	 * until sched_init_smp() has been run. It will set the allowed
690 	 * CPUs for init to the non isolated CPUs.
691 	 */
692 	rcu_read_lock();
693 	tsk = find_task_by_pid_ns(pid, &init_pid_ns);
694 	set_cpus_allowed_ptr(tsk, cpumask_of(smp_processor_id()));
695 	rcu_read_unlock();
696 
697 	numa_default_policy();
698 	pid = kernel_thread(kthreadd, NULL, CLONE_FS | CLONE_FILES);
699 	rcu_read_lock();
700 	kthreadd_task = find_task_by_pid_ns(pid, &init_pid_ns);
701 	rcu_read_unlock();
702 
703 	/*
704 	 * Enable might_sleep() and smp_processor_id() checks.
705 	 * They cannot be enabled earlier because with CONFIG_PREEMPTION=y
706 	 * kernel_thread() would trigger might_sleep() splats. With
707 	 * CONFIG_PREEMPT_VOLUNTARY=y the init task might have scheduled
708 	 * already, but it's stuck on the kthreadd_done completion.
709 	 */
710 	system_state = SYSTEM_SCHEDULING;
711 
712 	complete(&kthreadd_done);
713 
714 	/*
715 	 * The boot idle thread must execute schedule()
716 	 * at least once to get things moving:
717 	 */
718 	schedule_preempt_disabled();
719 	/* Call into cpu_idle with preempt disabled */
720 	cpu_startup_entry(CPUHP_ONLINE);
721 }
722 
723 /* Check for early params. */
724 static int __init do_early_param(char *param, char *val,
725 				 const char *unused, void *arg)
726 {
727 	const struct obs_kernel_param *p;
728 
729 	for (p = __setup_start; p < __setup_end; p++) {
730 		if ((p->early && parameq(param, p->str)) ||
731 		    (strcmp(param, "console") == 0 &&
732 		     strcmp(p->str, "earlycon") == 0)
733 		) {
734 			if (p->setup_func(val) != 0)
735 				pr_warn("Malformed early option '%s'\n", param);
736 		}
737 	}
738 	/* We accept everything at this stage. */
739 	return 0;
740 }
741 
742 void __init parse_early_options(char *cmdline)
743 {
744 	parse_args("early options", cmdline, NULL, 0, 0, 0, NULL,
745 		   do_early_param);
746 }
747 
748 /* Arch code calls this early on, or if not, just before other parsing. */
749 void __init parse_early_param(void)
750 {
751 	static int done __initdata;
752 	static char tmp_cmdline[COMMAND_LINE_SIZE] __initdata;
753 
754 	if (done)
755 		return;
756 
757 	/* All fall through to do_early_param. */
758 	strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);
759 	parse_early_options(tmp_cmdline);
760 	done = 1;
761 }
762 
763 void __init __weak arch_post_acpi_subsys_init(void) { }
764 
765 void __init __weak smp_setup_processor_id(void)
766 {
767 }
768 
769 # if THREAD_SIZE >= PAGE_SIZE
770 void __init __weak thread_stack_cache_init(void)
771 {
772 }
773 #endif
774 
775 void __init __weak mem_encrypt_init(void) { }
776 
777 void __init __weak poking_init(void) { }
778 
779 void __init __weak pgtable_cache_init(void) { }
780 
781 bool initcall_debug;
782 core_param(initcall_debug, initcall_debug, bool, 0644);
783 
784 #ifdef TRACEPOINTS_ENABLED
785 static void __init initcall_debug_enable(void);
786 #else
787 static inline void initcall_debug_enable(void)
788 {
789 }
790 #endif
791 
792 /* Report memory auto-initialization states for this boot. */
793 static void __init report_meminit(void)
794 {
795 	const char *stack;
796 
797 	if (IS_ENABLED(CONFIG_INIT_STACK_ALL_PATTERN))
798 		stack = "all(pattern)";
799 	else if (IS_ENABLED(CONFIG_INIT_STACK_ALL_ZERO))
800 		stack = "all(zero)";
801 	else if (IS_ENABLED(CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL))
802 		stack = "byref_all(zero)";
803 	else if (IS_ENABLED(CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF))
804 		stack = "byref(zero)";
805 	else if (IS_ENABLED(CONFIG_GCC_PLUGIN_STRUCTLEAK_USER))
806 		stack = "__user(zero)";
807 	else
808 		stack = "off";
809 
810 	pr_info("mem auto-init: stack:%s, heap alloc:%s, heap free:%s\n",
811 		stack, want_init_on_alloc(GFP_KERNEL) ? "on" : "off",
812 		want_init_on_free() ? "on" : "off");
813 	if (want_init_on_free())
814 		pr_info("mem auto-init: clearing system memory may take some time...\n");
815 }
816 
817 /*
818  * Set up kernel memory allocators
819  */
820 static void __init mm_init(void)
821 {
822 	/*
823 	 * page_ext requires contiguous pages,
824 	 * bigger than MAX_ORDER unless SPARSEMEM.
825 	 */
826 	page_ext_init_flatmem();
827 	init_mem_debugging_and_hardening();
828 	report_meminit();
829 	mem_init();
830 	/* page_owner must be initialized after buddy is ready */
831 	page_ext_init_flatmem_late();
832 	kmem_cache_init();
833 	kmemleak_init();
834 	pgtable_init();
835 	debug_objects_mem_init();
836 	vmalloc_init();
837 	ioremap_huge_init();
838 	/* Should be run before the first non-init thread is created */
839 	init_espfix_bsp();
840 	/* Should be run after espfix64 is set up. */
841 	pti_init();
842 }
843 
844 void __init __weak arch_call_rest_init(void)
845 {
846 	rest_init();
847 }
848 
849 asmlinkage __visible void __init __no_sanitize_address start_kernel(void)
850 {
851 	char *command_line;
852 	char *after_dashes;
853 
854 	set_task_stack_end_magic(&init_task);
855 	smp_setup_processor_id();
856 	debug_objects_early_init();
857 
858 	cgroup_init_early();
859 
860 	local_irq_disable();
861 	early_boot_irqs_disabled = true;
862 
863 	/*
864 	 * Interrupts are still disabled. Do necessary setups, then
865 	 * enable them.
866 	 */
867 	boot_cpu_init();
868 	page_address_init();
869 	pr_notice("%s", linux_banner);
870 	early_security_init();
871 	setup_arch(&command_line);
872 	setup_boot_config(command_line);
873 	setup_command_line(command_line);
874 	setup_nr_cpu_ids();
875 	setup_per_cpu_areas();
876 	smp_prepare_boot_cpu();	/* arch-specific boot-cpu hooks */
877 	boot_cpu_hotplug_init();
878 
879 	build_all_zonelists(NULL);
880 	page_alloc_init();
881 
882 	pr_notice("Kernel command line: %s\n", saved_command_line);
883 	/* parameters may set static keys */
884 	jump_label_init();
885 	parse_early_param();
886 	after_dashes = parse_args("Booting kernel",
887 				  static_command_line, __start___param,
888 				  __stop___param - __start___param,
889 				  -1, -1, NULL, &unknown_bootoption);
890 	if (!IS_ERR_OR_NULL(after_dashes))
891 		parse_args("Setting init args", after_dashes, NULL, 0, -1, -1,
892 			   NULL, set_init_arg);
893 	if (extra_init_args)
894 		parse_args("Setting extra init args", extra_init_args,
895 			   NULL, 0, -1, -1, NULL, set_init_arg);
896 
897 	/*
898 	 * These use large bootmem allocations and must precede
899 	 * kmem_cache_init()
900 	 */
901 	setup_log_buf(0);
902 	vfs_caches_init_early();
903 	sort_main_extable();
904 	trap_init();
905 	mm_init();
906 
907 	ftrace_init();
908 
909 	/* trace_printk can be enabled here */
910 	early_trace_init();
911 
912 	/*
913 	 * Set up the scheduler prior starting any interrupts (such as the
914 	 * timer interrupt). Full topology setup happens at smp_init()
915 	 * time - but meanwhile we still have a functioning scheduler.
916 	 */
917 	sched_init();
918 	/*
919 	 * Disable preemption - early bootup scheduling is extremely
920 	 * fragile until we cpu_idle() for the first time.
921 	 */
922 	preempt_disable();
923 	if (WARN(!irqs_disabled(),
924 		 "Interrupts were enabled *very* early, fixing it\n"))
925 		local_irq_disable();
926 	radix_tree_init();
927 
928 	/*
929 	 * Set up housekeeping before setting up workqueues to allow the unbound
930 	 * workqueue to take non-housekeeping into account.
931 	 */
932 	housekeeping_init();
933 
934 	/*
935 	 * Allow workqueue creation and work item queueing/cancelling
936 	 * early.  Work item execution depends on kthreads and starts after
937 	 * workqueue_init().
938 	 */
939 	workqueue_init_early();
940 
941 	rcu_init();
942 
943 	/* Trace events are available after this */
944 	trace_init();
945 
946 	if (initcall_debug)
947 		initcall_debug_enable();
948 
949 	context_tracking_init();
950 	/* init some links before init_ISA_irqs() */
951 	early_irq_init();
952 	init_IRQ();
953 	tick_init();
954 	rcu_init_nohz();
955 	init_timers();
956 	hrtimers_init();
957 	softirq_init();
958 	timekeeping_init();
959 
960 	/*
961 	 * For best initial stack canary entropy, prepare it after:
962 	 * - setup_arch() for any UEFI RNG entropy and boot cmdline access
963 	 * - timekeeping_init() for ktime entropy used in rand_initialize()
964 	 * - rand_initialize() to get any arch-specific entropy like RDRAND
965 	 * - add_latent_entropy() to get any latent entropy
966 	 * - adding command line entropy
967 	 */
968 	rand_initialize();
969 	add_latent_entropy();
970 	add_device_randomness(command_line, strlen(command_line));
971 	boot_init_stack_canary();
972 
973 	time_init();
974 	perf_event_init();
975 	profile_init();
976 	call_function_init();
977 	WARN(!irqs_disabled(), "Interrupts were enabled early\n");
978 
979 	early_boot_irqs_disabled = false;
980 	local_irq_enable();
981 
982 	kmem_cache_init_late();
983 
984 	/*
985 	 * HACK ALERT! This is early. We're enabling the console before
986 	 * we've done PCI setups etc, and console_init() must be aware of
987 	 * this. But we do want output early, in case something goes wrong.
988 	 */
989 	console_init();
990 	if (panic_later)
991 		panic("Too many boot %s vars at `%s'", panic_later,
992 		      panic_param);
993 
994 	lockdep_init();
995 
996 	/*
997 	 * Need to run this when irqs are enabled, because it wants
998 	 * to self-test [hard/soft]-irqs on/off lock inversion bugs
999 	 * too:
1000 	 */
1001 	locking_selftest();
1002 
1003 	/*
1004 	 * This needs to be called before any devices perform DMA
1005 	 * operations that might use the SWIOTLB bounce buffers. It will
1006 	 * mark the bounce buffers as decrypted so that their usage will
1007 	 * not cause "plain-text" data to be decrypted when accessed.
1008 	 */
1009 	mem_encrypt_init();
1010 
1011 #ifdef CONFIG_BLK_DEV_INITRD
1012 	if (initrd_start && !initrd_below_start_ok &&
1013 	    page_to_pfn(virt_to_page((void *)initrd_start)) < min_low_pfn) {
1014 		pr_crit("initrd overwritten (0x%08lx < 0x%08lx) - disabling it.\n",
1015 		    page_to_pfn(virt_to_page((void *)initrd_start)),
1016 		    min_low_pfn);
1017 		initrd_start = 0;
1018 	}
1019 #endif
1020 	setup_per_cpu_pageset();
1021 	numa_policy_init();
1022 	acpi_early_init();
1023 	if (late_time_init)
1024 		late_time_init();
1025 	sched_clock_init();
1026 	calibrate_delay();
1027 	pid_idr_init();
1028 	anon_vma_init();
1029 #ifdef CONFIG_X86
1030 	if (efi_enabled(EFI_RUNTIME_SERVICES))
1031 		efi_enter_virtual_mode();
1032 #endif
1033 	thread_stack_cache_init();
1034 	cred_init();
1035 	fork_init();
1036 	proc_caches_init();
1037 	uts_ns_init();
1038 	key_init();
1039 	security_init();
1040 	dbg_late_init();
1041 	vfs_caches_init();
1042 	pagecache_init();
1043 	signals_init();
1044 	seq_file_init();
1045 	proc_root_init();
1046 	nsfs_init();
1047 	cpuset_init();
1048 	cgroup_init();
1049 	taskstats_init_early();
1050 	delayacct_init();
1051 
1052 	poking_init();
1053 	check_bugs();
1054 
1055 	acpi_subsystem_init();
1056 	arch_post_acpi_subsys_init();
1057 	sfi_init_late();
1058 	kcsan_init();
1059 
1060 	/* Do the rest non-__init'ed, we're now alive */
1061 	arch_call_rest_init();
1062 
1063 	prevent_tail_call_optimization();
1064 }
1065 
1066 /* Call all constructor functions linked into the kernel. */
1067 static void __init do_ctors(void)
1068 {
1069 #ifdef CONFIG_CONSTRUCTORS
1070 	ctor_fn_t *fn = (ctor_fn_t *) __ctors_start;
1071 
1072 	for (; fn < (ctor_fn_t *) __ctors_end; fn++)
1073 		(*fn)();
1074 #endif
1075 }
1076 
1077 #ifdef CONFIG_KALLSYMS
1078 struct blacklist_entry {
1079 	struct list_head next;
1080 	char *buf;
1081 };
1082 
1083 static __initdata_or_module LIST_HEAD(blacklisted_initcalls);
1084 
1085 static int __init initcall_blacklist(char *str)
1086 {
1087 	char *str_entry;
1088 	struct blacklist_entry *entry;
1089 
1090 	/* str argument is a comma-separated list of functions */
1091 	do {
1092 		str_entry = strsep(&str, ",");
1093 		if (str_entry) {
1094 			pr_debug("blacklisting initcall %s\n", str_entry);
1095 			entry = memblock_alloc(sizeof(*entry),
1096 					       SMP_CACHE_BYTES);
1097 			if (!entry)
1098 				panic("%s: Failed to allocate %zu bytes\n",
1099 				      __func__, sizeof(*entry));
1100 			entry->buf = memblock_alloc(strlen(str_entry) + 1,
1101 						    SMP_CACHE_BYTES);
1102 			if (!entry->buf)
1103 				panic("%s: Failed to allocate %zu bytes\n",
1104 				      __func__, strlen(str_entry) + 1);
1105 			strcpy(entry->buf, str_entry);
1106 			list_add(&entry->next, &blacklisted_initcalls);
1107 		}
1108 	} while (str_entry);
1109 
1110 	return 0;
1111 }
1112 
1113 static bool __init_or_module initcall_blacklisted(initcall_t fn)
1114 {
1115 	struct blacklist_entry *entry;
1116 	char fn_name[KSYM_SYMBOL_LEN];
1117 	unsigned long addr;
1118 
1119 	if (list_empty(&blacklisted_initcalls))
1120 		return false;
1121 
1122 	addr = (unsigned long) dereference_function_descriptor(fn);
1123 	sprint_symbol_no_offset(fn_name, addr);
1124 
1125 	/*
1126 	 * fn will be "function_name [module_name]" where [module_name] is not
1127 	 * displayed for built-in init functions.  Strip off the [module_name].
1128 	 */
1129 	strreplace(fn_name, ' ', '\0');
1130 
1131 	list_for_each_entry(entry, &blacklisted_initcalls, next) {
1132 		if (!strcmp(fn_name, entry->buf)) {
1133 			pr_debug("initcall %s blacklisted\n", fn_name);
1134 			return true;
1135 		}
1136 	}
1137 
1138 	return false;
1139 }
1140 #else
1141 static int __init initcall_blacklist(char *str)
1142 {
1143 	pr_warn("initcall_blacklist requires CONFIG_KALLSYMS\n");
1144 	return 0;
1145 }
1146 
1147 static bool __init_or_module initcall_blacklisted(initcall_t fn)
1148 {
1149 	return false;
1150 }
1151 #endif
1152 __setup("initcall_blacklist=", initcall_blacklist);
1153 
1154 static __init_or_module void
1155 trace_initcall_start_cb(void *data, initcall_t fn)
1156 {
1157 	ktime_t *calltime = (ktime_t *)data;
1158 
1159 	printk(KERN_DEBUG "calling  %pS @ %i\n", fn, task_pid_nr(current));
1160 	*calltime = ktime_get();
1161 }
1162 
1163 static __init_or_module void
1164 trace_initcall_finish_cb(void *data, initcall_t fn, int ret)
1165 {
1166 	ktime_t *calltime = (ktime_t *)data;
1167 	ktime_t delta, rettime;
1168 	unsigned long long duration;
1169 
1170 	rettime = ktime_get();
1171 	delta = ktime_sub(rettime, *calltime);
1172 	duration = (unsigned long long) ktime_to_ns(delta) >> 10;
1173 	printk(KERN_DEBUG "initcall %pS returned %d after %lld usecs\n",
1174 		 fn, ret, duration);
1175 }
1176 
1177 static ktime_t initcall_calltime;
1178 
1179 #ifdef TRACEPOINTS_ENABLED
1180 static void __init initcall_debug_enable(void)
1181 {
1182 	int ret;
1183 
1184 	ret = register_trace_initcall_start(trace_initcall_start_cb,
1185 					    &initcall_calltime);
1186 	ret |= register_trace_initcall_finish(trace_initcall_finish_cb,
1187 					      &initcall_calltime);
1188 	WARN(ret, "Failed to register initcall tracepoints\n");
1189 }
1190 # define do_trace_initcall_start	trace_initcall_start
1191 # define do_trace_initcall_finish	trace_initcall_finish
1192 #else
1193 static inline void do_trace_initcall_start(initcall_t fn)
1194 {
1195 	if (!initcall_debug)
1196 		return;
1197 	trace_initcall_start_cb(&initcall_calltime, fn);
1198 }
1199 static inline void do_trace_initcall_finish(initcall_t fn, int ret)
1200 {
1201 	if (!initcall_debug)
1202 		return;
1203 	trace_initcall_finish_cb(&initcall_calltime, fn, ret);
1204 }
1205 #endif /* !TRACEPOINTS_ENABLED */
1206 
1207 int __init_or_module do_one_initcall(initcall_t fn)
1208 {
1209 	int count = preempt_count();
1210 	char msgbuf[64];
1211 	int ret;
1212 
1213 	if (initcall_blacklisted(fn))
1214 		return -EPERM;
1215 
1216 	do_trace_initcall_start(fn);
1217 	ret = fn();
1218 	do_trace_initcall_finish(fn, ret);
1219 
1220 	msgbuf[0] = 0;
1221 
1222 	if (preempt_count() != count) {
1223 		sprintf(msgbuf, "preemption imbalance ");
1224 		preempt_count_set(count);
1225 	}
1226 	if (irqs_disabled()) {
1227 		strlcat(msgbuf, "disabled interrupts ", sizeof(msgbuf));
1228 		local_irq_enable();
1229 	}
1230 	WARN(msgbuf[0], "initcall %pS returned with %s\n", fn, msgbuf);
1231 
1232 	add_latent_entropy();
1233 	return ret;
1234 }
1235 
1236 
1237 extern initcall_entry_t __initcall_start[];
1238 extern initcall_entry_t __initcall0_start[];
1239 extern initcall_entry_t __initcall1_start[];
1240 extern initcall_entry_t __initcall2_start[];
1241 extern initcall_entry_t __initcall3_start[];
1242 extern initcall_entry_t __initcall4_start[];
1243 extern initcall_entry_t __initcall5_start[];
1244 extern initcall_entry_t __initcall6_start[];
1245 extern initcall_entry_t __initcall7_start[];
1246 extern initcall_entry_t __initcall_end[];
1247 
1248 static initcall_entry_t *initcall_levels[] __initdata = {
1249 	__initcall0_start,
1250 	__initcall1_start,
1251 	__initcall2_start,
1252 	__initcall3_start,
1253 	__initcall4_start,
1254 	__initcall5_start,
1255 	__initcall6_start,
1256 	__initcall7_start,
1257 	__initcall_end,
1258 };
1259 
1260 /* Keep these in sync with initcalls in include/linux/init.h */
1261 static const char *initcall_level_names[] __initdata = {
1262 	"pure",
1263 	"core",
1264 	"postcore",
1265 	"arch",
1266 	"subsys",
1267 	"fs",
1268 	"device",
1269 	"late",
1270 };
1271 
1272 static int __init ignore_unknown_bootoption(char *param, char *val,
1273 			       const char *unused, void *arg)
1274 {
1275 	return 0;
1276 }
1277 
1278 static void __init do_initcall_level(int level, char *command_line)
1279 {
1280 	initcall_entry_t *fn;
1281 
1282 	parse_args(initcall_level_names[level],
1283 		   command_line, __start___param,
1284 		   __stop___param - __start___param,
1285 		   level, level,
1286 		   NULL, ignore_unknown_bootoption);
1287 
1288 	trace_initcall_level(initcall_level_names[level]);
1289 	for (fn = initcall_levels[level]; fn < initcall_levels[level+1]; fn++)
1290 		do_one_initcall(initcall_from_entry(fn));
1291 }
1292 
1293 static void __init do_initcalls(void)
1294 {
1295 	int level;
1296 	size_t len = strlen(saved_command_line) + 1;
1297 	char *command_line;
1298 
1299 	command_line = kzalloc(len, GFP_KERNEL);
1300 	if (!command_line)
1301 		panic("%s: Failed to allocate %zu bytes\n", __func__, len);
1302 
1303 	for (level = 0; level < ARRAY_SIZE(initcall_levels) - 1; level++) {
1304 		/* Parser modifies command_line, restore it each time */
1305 		strcpy(command_line, saved_command_line);
1306 		do_initcall_level(level, command_line);
1307 	}
1308 
1309 	kfree(command_line);
1310 }
1311 
1312 /*
1313  * Ok, the machine is now initialized. None of the devices
1314  * have been touched yet, but the CPU subsystem is up and
1315  * running, and memory and process management works.
1316  *
1317  * Now we can finally start doing some real work..
1318  */
1319 static void __init do_basic_setup(void)
1320 {
1321 	cpuset_init_smp();
1322 	driver_init();
1323 	init_irq_proc();
1324 	do_ctors();
1325 	usermodehelper_enable();
1326 	do_initcalls();
1327 }
1328 
1329 static void __init do_pre_smp_initcalls(void)
1330 {
1331 	initcall_entry_t *fn;
1332 
1333 	trace_initcall_level("early");
1334 	for (fn = __initcall_start; fn < __initcall0_start; fn++)
1335 		do_one_initcall(initcall_from_entry(fn));
1336 }
1337 
1338 static int run_init_process(const char *init_filename)
1339 {
1340 	const char *const *p;
1341 
1342 	argv_init[0] = init_filename;
1343 	pr_info("Run %s as init process\n", init_filename);
1344 	pr_debug("  with arguments:\n");
1345 	for (p = argv_init; *p; p++)
1346 		pr_debug("    %s\n", *p);
1347 	pr_debug("  with environment:\n");
1348 	for (p = envp_init; *p; p++)
1349 		pr_debug("    %s\n", *p);
1350 	return kernel_execve(init_filename, argv_init, envp_init);
1351 }
1352 
1353 static int try_to_run_init_process(const char *init_filename)
1354 {
1355 	int ret;
1356 
1357 	ret = run_init_process(init_filename);
1358 
1359 	if (ret && ret != -ENOENT) {
1360 		pr_err("Starting init: %s exists but couldn't execute it (error %d)\n",
1361 		       init_filename, ret);
1362 	}
1363 
1364 	return ret;
1365 }
1366 
1367 static noinline void __init kernel_init_freeable(void);
1368 
1369 #if defined(CONFIG_STRICT_KERNEL_RWX) || defined(CONFIG_STRICT_MODULE_RWX)
1370 bool rodata_enabled __ro_after_init = true;
1371 static int __init set_debug_rodata(char *str)
1372 {
1373 	return strtobool(str, &rodata_enabled);
1374 }
1375 __setup("rodata=", set_debug_rodata);
1376 #endif
1377 
1378 #ifdef CONFIG_STRICT_KERNEL_RWX
1379 static void mark_readonly(void)
1380 {
1381 	if (rodata_enabled) {
1382 		/*
1383 		 * load_module() results in W+X mappings, which are cleaned
1384 		 * up with call_rcu().  Let's make sure that queued work is
1385 		 * flushed so that we don't hit false positives looking for
1386 		 * insecure pages which are W+X.
1387 		 */
1388 		rcu_barrier();
1389 		mark_rodata_ro();
1390 		rodata_test();
1391 	} else
1392 		pr_info("Kernel memory protection disabled.\n");
1393 }
1394 #elif defined(CONFIG_ARCH_HAS_STRICT_KERNEL_RWX)
1395 static inline void mark_readonly(void)
1396 {
1397 	pr_warn("Kernel memory protection not selected by kernel config.\n");
1398 }
1399 #else
1400 static inline void mark_readonly(void)
1401 {
1402 	pr_warn("This architecture does not have kernel memory protection.\n");
1403 }
1404 #endif
1405 
1406 void __weak free_initmem(void)
1407 {
1408 	free_initmem_default(POISON_FREE_INITMEM);
1409 }
1410 
1411 static int __ref kernel_init(void *unused)
1412 {
1413 	int ret;
1414 
1415 	kernel_init_freeable();
1416 	/* need to finish all async __init code before freeing the memory */
1417 	async_synchronize_full();
1418 	kprobe_free_init_mem();
1419 	ftrace_free_init_mem();
1420 	free_initmem();
1421 	mark_readonly();
1422 
1423 	/*
1424 	 * Kernel mappings are now finalized - update the userspace page-table
1425 	 * to finalize PTI.
1426 	 */
1427 	pti_finalize();
1428 
1429 	system_state = SYSTEM_RUNNING;
1430 	numa_default_policy();
1431 
1432 	rcu_end_inkernel_boot();
1433 
1434 	do_sysctl_args();
1435 
1436 	if (ramdisk_execute_command) {
1437 		ret = run_init_process(ramdisk_execute_command);
1438 		if (!ret)
1439 			return 0;
1440 		pr_err("Failed to execute %s (error %d)\n",
1441 		       ramdisk_execute_command, ret);
1442 	}
1443 
1444 	/*
1445 	 * We try each of these until one succeeds.
1446 	 *
1447 	 * The Bourne shell can be used instead of init if we are
1448 	 * trying to recover a really broken machine.
1449 	 */
1450 	if (execute_command) {
1451 		ret = run_init_process(execute_command);
1452 		if (!ret)
1453 			return 0;
1454 		panic("Requested init %s failed (error %d).",
1455 		      execute_command, ret);
1456 	}
1457 
1458 	if (CONFIG_DEFAULT_INIT[0] != '\0') {
1459 		ret = run_init_process(CONFIG_DEFAULT_INIT);
1460 		if (ret)
1461 			pr_err("Default init %s failed (error %d)\n",
1462 			       CONFIG_DEFAULT_INIT, ret);
1463 		else
1464 			return 0;
1465 	}
1466 
1467 	if (!try_to_run_init_process("/sbin/init") ||
1468 	    !try_to_run_init_process("/etc/init") ||
1469 	    !try_to_run_init_process("/bin/init") ||
1470 	    !try_to_run_init_process("/bin/sh"))
1471 		return 0;
1472 
1473 	panic("No working init found.  Try passing init= option to kernel. "
1474 	      "See Linux Documentation/admin-guide/init.rst for guidance.");
1475 }
1476 
1477 /* Open /dev/console, for stdin/stdout/stderr, this should never fail */
1478 void __init console_on_rootfs(void)
1479 {
1480 	struct file *file = filp_open("/dev/console", O_RDWR, 0);
1481 
1482 	if (IS_ERR(file)) {
1483 		pr_err("Warning: unable to open an initial console. Fallback to ttynull.\n");
1484 		register_ttynull_console();
1485 
1486 		file = filp_open("/dev/console", O_RDWR, 0);
1487 		if (IS_ERR(file)) {
1488 			pr_err("Warning: Failed to add ttynull console. No stdin, stdout, and stderr for the init process!\n");
1489 			return;
1490 		}
1491 	}
1492 	init_dup(file);
1493 	init_dup(file);
1494 	init_dup(file);
1495 	fput(file);
1496 }
1497 
1498 static noinline void __init kernel_init_freeable(void)
1499 {
1500 	/*
1501 	 * Wait until kthreadd is all set-up.
1502 	 */
1503 	wait_for_completion(&kthreadd_done);
1504 
1505 	/* Now the scheduler is fully set up and can do blocking allocations */
1506 	gfp_allowed_mask = __GFP_BITS_MASK;
1507 
1508 	/*
1509 	 * init can allocate pages on any node
1510 	 */
1511 	set_mems_allowed(node_states[N_MEMORY]);
1512 
1513 	cad_pid = task_pid(current);
1514 
1515 	smp_prepare_cpus(setup_max_cpus);
1516 
1517 	workqueue_init();
1518 
1519 	init_mm_internals();
1520 
1521 	do_pre_smp_initcalls();
1522 	lockup_detector_init();
1523 
1524 	smp_init();
1525 	sched_init_smp();
1526 
1527 	padata_init();
1528 	page_alloc_init_late();
1529 	/* Initialize page ext after all struct pages are initialized. */
1530 	page_ext_init();
1531 
1532 	do_basic_setup();
1533 
1534 	kunit_run_all_tests();
1535 
1536 	console_on_rootfs();
1537 
1538 	/*
1539 	 * check if there is an early userspace init.  If yes, let it do all
1540 	 * the work
1541 	 */
1542 	if (init_eaccess(ramdisk_execute_command) != 0) {
1543 		ramdisk_execute_command = NULL;
1544 		prepare_namespace();
1545 	}
1546 
1547 	/*
1548 	 * Ok, we have completed the initial bootup, and
1549 	 * we're essentially up and running. Get rid of the
1550 	 * initmem segments and start the user-mode stuff..
1551 	 *
1552 	 * rootfs is available now, try loading the public keys
1553 	 * and default modules
1554 	 */
1555 
1556 	integrity_load_keys();
1557 }
1558