1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  *  linux/init/main.c
4  *
5  *  Copyright (C) 1991, 1992  Linus Torvalds
6  *
7  *  GK 2/5/95  -  Changed to support mounting root fs via NFS
8  *  Added initrd & change_root: Werner Almesberger & Hans Lermen, Feb '96
9  *  Moan early if gcc is old, avoiding bogus kernels - Paul Gortmaker, May '96
10  *  Simplified starting of init:  Michael A. Griffith <grif@acm.org>
11  */
12 
13 #define DEBUG		/* Enable initcall_debug */
14 
15 #include <linux/types.h>
16 #include <linux/extable.h>
17 #include <linux/module.h>
18 #include <linux/proc_fs.h>
19 #include <linux/binfmts.h>
20 #include <linux/kernel.h>
21 #include <linux/syscalls.h>
22 #include <linux/stackprotector.h>
23 #include <linux/string.h>
24 #include <linux/ctype.h>
25 #include <linux/delay.h>
26 #include <linux/ioport.h>
27 #include <linux/init.h>
28 #include <linux/initrd.h>
29 #include <linux/memblock.h>
30 #include <linux/acpi.h>
31 #include <linux/bootconfig.h>
32 #include <linux/console.h>
33 #include <linux/nmi.h>
34 #include <linux/percpu.h>
35 #include <linux/kmod.h>
36 #include <linux/kprobes.h>
37 #include <linux/kmsan.h>
38 #include <linux/vmalloc.h>
39 #include <linux/kernel_stat.h>
40 #include <linux/start_kernel.h>
41 #include <linux/security.h>
42 #include <linux/smp.h>
43 #include <linux/profile.h>
44 #include <linux/kfence.h>
45 #include <linux/rcupdate.h>
46 #include <linux/srcu.h>
47 #include <linux/moduleparam.h>
48 #include <linux/kallsyms.h>
49 #include <linux/buildid.h>
50 #include <linux/writeback.h>
51 #include <linux/cpu.h>
52 #include <linux/cpuset.h>
53 #include <linux/cgroup.h>
54 #include <linux/efi.h>
55 #include <linux/tick.h>
56 #include <linux/sched/isolation.h>
57 #include <linux/interrupt.h>
58 #include <linux/taskstats_kern.h>
59 #include <linux/delayacct.h>
60 #include <linux/unistd.h>
61 #include <linux/utsname.h>
62 #include <linux/rmap.h>
63 #include <linux/mempolicy.h>
64 #include <linux/key.h>
65 #include <linux/debug_locks.h>
66 #include <linux/debugobjects.h>
67 #include <linux/lockdep.h>
68 #include <linux/kmemleak.h>
69 #include <linux/padata.h>
70 #include <linux/pid_namespace.h>
71 #include <linux/device/driver.h>
72 #include <linux/kthread.h>
73 #include <linux/sched.h>
74 #include <linux/sched/init.h>
75 #include <linux/signal.h>
76 #include <linux/idr.h>
77 #include <linux/kgdb.h>
78 #include <linux/ftrace.h>
79 #include <linux/async.h>
80 #include <linux/shmem_fs.h>
81 #include <linux/slab.h>
82 #include <linux/perf_event.h>
83 #include <linux/ptrace.h>
84 #include <linux/pti.h>
85 #include <linux/blkdev.h>
86 #include <linux/sched/clock.h>
87 #include <linux/sched/task.h>
88 #include <linux/sched/task_stack.h>
89 #include <linux/context_tracking.h>
90 #include <linux/random.h>
91 #include <linux/list.h>
92 #include <linux/integrity.h>
93 #include <linux/proc_ns.h>
94 #include <linux/io.h>
95 #include <linux/cache.h>
96 #include <linux/rodata_test.h>
97 #include <linux/jump_label.h>
98 #include <linux/kcsan.h>
99 #include <linux/init_syscalls.h>
100 #include <linux/stackdepot.h>
101 #include <linux/randomize_kstack.h>
102 #include <net/net_namespace.h>
103 
104 #include <asm/io.h>
105 #include <asm/setup.h>
106 #include <asm/sections.h>
107 #include <asm/cacheflush.h>
108 
109 #define CREATE_TRACE_POINTS
110 #include <trace/events/initcall.h>
111 
112 #include <kunit/test.h>
113 
114 static int kernel_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 /* Default late time init is NULL. archs can override this later. */
135 void (*__initdata late_time_init)(void);
136 
137 /* Untouched command line saved by arch-specific code. */
138 char __initdata boot_command_line[COMMAND_LINE_SIZE];
139 /* Untouched saved command line (eg. for /proc) */
140 char *saved_command_line __ro_after_init;
141 unsigned int saved_command_line_len __ro_after_init;
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 size_t initargs_offs;
153 #else
154 # define bootconfig_found false
155 # define initargs_offs 0
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 
set_reset_devices(char * str)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 
obsolete_checksetup(char * line)192 static bool __init obsolete_checksetup(char *line)
193 {
194 	const struct obs_kernel_param *p;
195 	bool had_early_param = false;
196 
197 	p = __setup_start;
198 	do {
199 		int n = strlen(p->str);
200 		if (parameqn(line, p->str, n)) {
201 			if (p->early) {
202 				/* Already done in parse_early_param?
203 				 * (Needs exact match on param part).
204 				 * Keep iterating, as we can have early
205 				 * params and __setups of same names 8( */
206 				if (line[n] == '\0' || line[n] == '=')
207 					had_early_param = true;
208 			} else if (!p->setup_func) {
209 				pr_warn("Parameter %s is obsolete, ignored\n",
210 					p->str);
211 				return true;
212 			} else if (p->setup_func(line + n))
213 				return true;
214 		}
215 		p++;
216 	} while (p < __setup_end);
217 
218 	return had_early_param;
219 }
220 
221 /*
222  * This should be approx 2 Bo*oMips to start (note initial shift), and will
223  * still work even if initially too large, it will just take slightly longer
224  */
225 unsigned long loops_per_jiffy = (1<<12);
226 EXPORT_SYMBOL(loops_per_jiffy);
227 
debug_kernel(char * str)228 static int __init debug_kernel(char *str)
229 {
230 	console_loglevel = CONSOLE_LOGLEVEL_DEBUG;
231 	return 0;
232 }
233 
quiet_kernel(char * str)234 static int __init quiet_kernel(char *str)
235 {
236 	console_loglevel = CONSOLE_LOGLEVEL_QUIET;
237 	return 0;
238 }
239 
240 early_param("debug", debug_kernel);
241 early_param("quiet", quiet_kernel);
242 
loglevel(char * str)243 static int __init loglevel(char *str)
244 {
245 	int newlevel;
246 
247 	/*
248 	 * Only update loglevel value when a correct setting was passed,
249 	 * to prevent blind crashes (when loglevel being set to 0) that
250 	 * are quite hard to debug
251 	 */
252 	if (get_option(&str, &newlevel)) {
253 		console_loglevel = newlevel;
254 		return 0;
255 	}
256 
257 	return -EINVAL;
258 }
259 
260 early_param("loglevel", loglevel);
261 
262 #ifdef CONFIG_BLK_DEV_INITRD
get_boot_config_from_initrd(size_t * _size)263 static void * __init get_boot_config_from_initrd(size_t *_size)
264 {
265 	u32 size, csum;
266 	char *data;
267 	u32 *hdr;
268 	int i;
269 
270 	if (!initrd_end)
271 		return NULL;
272 
273 	data = (char *)initrd_end - BOOTCONFIG_MAGIC_LEN;
274 	/*
275 	 * Since Grub may align the size of initrd to 4, we must
276 	 * check the preceding 3 bytes as well.
277 	 */
278 	for (i = 0; i < 4; i++) {
279 		if (!memcmp(data, BOOTCONFIG_MAGIC, BOOTCONFIG_MAGIC_LEN))
280 			goto found;
281 		data--;
282 	}
283 	return NULL;
284 
285 found:
286 	hdr = (u32 *)(data - 8);
287 	size = le32_to_cpu(hdr[0]);
288 	csum = le32_to_cpu(hdr[1]);
289 
290 	data = ((void *)hdr) - size;
291 	if ((unsigned long)data < initrd_start) {
292 		pr_err("bootconfig size %d is greater than initrd size %ld\n",
293 			size, initrd_end - initrd_start);
294 		return NULL;
295 	}
296 
297 	if (xbc_calc_checksum(data, size) != csum) {
298 		pr_err("bootconfig checksum failed\n");
299 		return NULL;
300 	}
301 
302 	/* Remove bootconfig from initramfs/initrd */
303 	initrd_end = (unsigned long)data;
304 	if (_size)
305 		*_size = size;
306 
307 	return data;
308 }
309 #else
get_boot_config_from_initrd(size_t * _size)310 static void * __init get_boot_config_from_initrd(size_t *_size)
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 
xbc_snprint_cmdline(char * buf,size_t size,struct xbc_node * root)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 */
xbc_make_cmdline(const char * key)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 		memblock_free(new_cmdline, len + 1);
383 		return NULL;
384 	}
385 
386 	return new_cmdline;
387 }
388 
bootconfig_params(char * param,char * val,const char * unused,void * arg)389 static int __init bootconfig_params(char *param, char *val,
390 				    const char *unused, void *arg)
391 {
392 	if (strcmp(param, "bootconfig") == 0) {
393 		bootconfig_found = true;
394 	}
395 	return 0;
396 }
397 
warn_bootconfig(char * str)398 static int __init warn_bootconfig(char *str)
399 {
400 	/* The 'bootconfig' has been handled by bootconfig_params(). */
401 	return 0;
402 }
403 
setup_boot_config(void)404 static void __init setup_boot_config(void)
405 {
406 	static char tmp_cmdline[COMMAND_LINE_SIZE] __initdata;
407 	const char *msg, *data;
408 	int pos, ret;
409 	size_t size;
410 	char *err;
411 
412 	/* Cut out the bootconfig data even if we have no bootconfig option */
413 	data = get_boot_config_from_initrd(&size);
414 	/* If there is no bootconfig in initrd, try embedded one. */
415 	if (!data)
416 		data = xbc_get_embedded_bootconfig(&size);
417 
418 	strscpy(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 || IS_ENABLED(CONFIG_BOOT_CONFIG_FORCE)))
423 		return;
424 
425 	/* parse_args() stops at the next param of '--' and returns an address */
426 	if (err)
427 		initargs_offs = err - tmp_cmdline;
428 
429 	if (!data) {
430 		/* If user intended to use bootconfig, show an error level message */
431 		if (bootconfig_found)
432 			pr_err("'bootconfig' found on command line, but no bootconfig found\n");
433 		else
434 			pr_info("No bootconfig data provided, so skipping bootconfig");
435 		return;
436 	}
437 
438 	if (size >= XBC_DATA_MAX) {
439 		pr_err("bootconfig size %ld greater than max size %d\n",
440 			(long)size, XBC_DATA_MAX);
441 		return;
442 	}
443 
444 	ret = xbc_init(data, size, &msg, &pos);
445 	if (ret < 0) {
446 		if (pos < 0)
447 			pr_err("Failed to init bootconfig: %s.\n", msg);
448 		else
449 			pr_err("Failed to parse bootconfig: %s at %d.\n",
450 				msg, pos);
451 	} else {
452 		xbc_get_info(&ret, NULL);
453 		pr_info("Load bootconfig: %ld bytes %d nodes\n", (long)size, ret);
454 		/* keys starting with "kernel." are passed via cmdline */
455 		extra_command_line = xbc_make_cmdline("kernel");
456 		/* Also, "init." keys are init arguments */
457 		extra_init_args = xbc_make_cmdline("init");
458 	}
459 	return;
460 }
461 
exit_boot_config(void)462 static void __init exit_boot_config(void)
463 {
464 	xbc_exit();
465 }
466 
467 #else	/* !CONFIG_BOOT_CONFIG */
468 
setup_boot_config(void)469 static void __init setup_boot_config(void)
470 {
471 	/* Remove bootconfig data from initrd */
472 	get_boot_config_from_initrd(NULL);
473 }
474 
warn_bootconfig(char * str)475 static int __init warn_bootconfig(char *str)
476 {
477 	pr_warn("WARNING: 'bootconfig' found on the kernel command line but CONFIG_BOOT_CONFIG is not set.\n");
478 	return 0;
479 }
480 
481 #define exit_boot_config()	do {} while (0)
482 
483 #endif	/* CONFIG_BOOT_CONFIG */
484 
485 early_param("bootconfig", warn_bootconfig);
486 
487 /* Change NUL term back to "=", to make "param" the whole string. */
repair_env_string(char * param,char * val)488 static void __init repair_env_string(char *param, char *val)
489 {
490 	if (val) {
491 		/* param=val or param="val"? */
492 		if (val == param+strlen(param)+1)
493 			val[-1] = '=';
494 		else if (val == param+strlen(param)+2) {
495 			val[-2] = '=';
496 			memmove(val-1, val, strlen(val)+1);
497 		} else
498 			BUG();
499 	}
500 }
501 
502 /* Anything after -- gets handed straight to init. */
set_init_arg(char * param,char * val,const char * unused,void * arg)503 static int __init set_init_arg(char *param, char *val,
504 			       const char *unused, void *arg)
505 {
506 	unsigned int i;
507 
508 	if (panic_later)
509 		return 0;
510 
511 	repair_env_string(param, val);
512 
513 	for (i = 0; argv_init[i]; i++) {
514 		if (i == MAX_INIT_ARGS) {
515 			panic_later = "init";
516 			panic_param = param;
517 			return 0;
518 		}
519 	}
520 	argv_init[i] = param;
521 	return 0;
522 }
523 
524 /*
525  * Unknown boot options get handed to init, unless they look like
526  * unused parameters (modprobe will find them in /proc/cmdline).
527  */
unknown_bootoption(char * param,char * val,const char * unused,void * arg)528 static int __init unknown_bootoption(char *param, char *val,
529 				     const char *unused, void *arg)
530 {
531 	size_t len = strlen(param);
532 
533 	/* Handle params aliased to sysctls */
534 	if (sysctl_is_alias(param))
535 		return 0;
536 
537 	repair_env_string(param, val);
538 
539 	/* Handle obsolete-style parameters */
540 	if (obsolete_checksetup(param))
541 		return 0;
542 
543 	/* Unused module parameter. */
544 	if (strnchr(param, len, '.'))
545 		return 0;
546 
547 	if (panic_later)
548 		return 0;
549 
550 	if (val) {
551 		/* Environment option */
552 		unsigned int i;
553 		for (i = 0; envp_init[i]; i++) {
554 			if (i == MAX_INIT_ENVS) {
555 				panic_later = "env";
556 				panic_param = param;
557 			}
558 			if (!strncmp(param, envp_init[i], len+1))
559 				break;
560 		}
561 		envp_init[i] = param;
562 	} else {
563 		/* Command line option */
564 		unsigned int i;
565 		for (i = 0; argv_init[i]; i++) {
566 			if (i == MAX_INIT_ARGS) {
567 				panic_later = "init";
568 				panic_param = param;
569 			}
570 		}
571 		argv_init[i] = param;
572 	}
573 	return 0;
574 }
575 
init_setup(char * str)576 static int __init init_setup(char *str)
577 {
578 	unsigned int i;
579 
580 	execute_command = str;
581 	/*
582 	 * In case LILO is going to boot us with default command line,
583 	 * it prepends "auto" before the whole cmdline which makes
584 	 * the shell think it should execute a script with such name.
585 	 * So we ignore all arguments entered _before_ init=... [MJ]
586 	 */
587 	for (i = 1; i < MAX_INIT_ARGS; i++)
588 		argv_init[i] = NULL;
589 	return 1;
590 }
591 __setup("init=", init_setup);
592 
rdinit_setup(char * str)593 static int __init rdinit_setup(char *str)
594 {
595 	unsigned int i;
596 
597 	ramdisk_execute_command = str;
598 	/* See "auto" comment in init_setup */
599 	for (i = 1; i < MAX_INIT_ARGS; i++)
600 		argv_init[i] = NULL;
601 	return 1;
602 }
603 __setup("rdinit=", rdinit_setup);
604 
605 #ifndef CONFIG_SMP
606 static const unsigned int setup_max_cpus = NR_CPUS;
setup_nr_cpu_ids(void)607 static inline void setup_nr_cpu_ids(void) { }
smp_prepare_cpus(unsigned int maxcpus)608 static inline void smp_prepare_cpus(unsigned int maxcpus) { }
609 #endif
610 
611 /*
612  * We need to store the untouched command line for future reference.
613  * We also need to store the touched command line since the parameter
614  * parsing is performed in place, and we should allow a component to
615  * store reference of name/value for future reference.
616  */
setup_command_line(char * command_line)617 static void __init setup_command_line(char *command_line)
618 {
619 	size_t len, xlen = 0, ilen = 0;
620 
621 	if (extra_command_line)
622 		xlen = strlen(extra_command_line);
623 	if (extra_init_args)
624 		ilen = strlen(extra_init_args) + 4; /* for " -- " */
625 
626 	len = xlen + strlen(boot_command_line) + 1;
627 
628 	saved_command_line = memblock_alloc(len + ilen, SMP_CACHE_BYTES);
629 	if (!saved_command_line)
630 		panic("%s: Failed to allocate %zu bytes\n", __func__, len + ilen);
631 
632 	static_command_line = memblock_alloc(len, SMP_CACHE_BYTES);
633 	if (!static_command_line)
634 		panic("%s: Failed to allocate %zu bytes\n", __func__, len);
635 
636 	if (xlen) {
637 		/*
638 		 * We have to put extra_command_line before boot command
639 		 * lines because there could be dashes (separator of init
640 		 * command line) in the command lines.
641 		 */
642 		strcpy(saved_command_line, extra_command_line);
643 		strcpy(static_command_line, extra_command_line);
644 	}
645 	strcpy(saved_command_line + xlen, boot_command_line);
646 	strcpy(static_command_line + xlen, command_line);
647 
648 	if (ilen) {
649 		/*
650 		 * Append supplemental init boot args to saved_command_line
651 		 * so that user can check what command line options passed
652 		 * to init.
653 		 * The order should always be
654 		 * " -- "[bootconfig init-param][cmdline init-param]
655 		 */
656 		if (initargs_offs) {
657 			len = xlen + initargs_offs;
658 			strcpy(saved_command_line + len, extra_init_args);
659 			len += ilen - 4;	/* strlen(extra_init_args) */
660 			strcpy(saved_command_line + len,
661 				boot_command_line + initargs_offs - 1);
662 		} else {
663 			len = strlen(saved_command_line);
664 			strcpy(saved_command_line + len, " -- ");
665 			len += 4;
666 			strcpy(saved_command_line + len, extra_init_args);
667 		}
668 	}
669 
670 	saved_command_line_len = strlen(saved_command_line);
671 }
672 
673 /*
674  * We need to finalize in a non-__init function or else race conditions
675  * between the root thread and the init thread may cause start_kernel to
676  * be reaped by free_initmem before the root thread has proceeded to
677  * cpu_idle.
678  *
679  * gcc-3.4 accidentally inlines this function, so use noinline.
680  */
681 
682 static __initdata DECLARE_COMPLETION(kthreadd_done);
683 
rest_init(void)684 noinline void __ref __noreturn rest_init(void)
685 {
686 	struct task_struct *tsk;
687 	int pid;
688 
689 	rcu_scheduler_starting();
690 	/*
691 	 * We need to spawn init first so that it obtains pid 1, however
692 	 * the init task will end up wanting to create kthreads, which, if
693 	 * we schedule it before we create kthreadd, will OOPS.
694 	 */
695 	pid = user_mode_thread(kernel_init, NULL, CLONE_FS);
696 	/*
697 	 * Pin init on the boot CPU. Task migration is not properly working
698 	 * until sched_init_smp() has been run. It will set the allowed
699 	 * CPUs for init to the non isolated CPUs.
700 	 */
701 	rcu_read_lock();
702 	tsk = find_task_by_pid_ns(pid, &init_pid_ns);
703 	tsk->flags |= PF_NO_SETAFFINITY;
704 	set_cpus_allowed_ptr(tsk, cpumask_of(smp_processor_id()));
705 	rcu_read_unlock();
706 
707 	numa_default_policy();
708 	pid = kernel_thread(kthreadd, NULL, NULL, CLONE_FS | CLONE_FILES);
709 	rcu_read_lock();
710 	kthreadd_task = find_task_by_pid_ns(pid, &init_pid_ns);
711 	rcu_read_unlock();
712 
713 	/*
714 	 * Enable might_sleep() and smp_processor_id() checks.
715 	 * They cannot be enabled earlier because with CONFIG_PREEMPTION=y
716 	 * kernel_thread() would trigger might_sleep() splats. With
717 	 * CONFIG_PREEMPT_VOLUNTARY=y the init task might have scheduled
718 	 * already, but it's stuck on the kthreadd_done completion.
719 	 */
720 	system_state = SYSTEM_SCHEDULING;
721 
722 	complete(&kthreadd_done);
723 
724 	/*
725 	 * The boot idle thread must execute schedule()
726 	 * at least once to get things moving:
727 	 */
728 	schedule_preempt_disabled();
729 	/* Call into cpu_idle with preempt disabled */
730 	cpu_startup_entry(CPUHP_ONLINE);
731 }
732 
733 /* Check for early params. */
do_early_param(char * param,char * val,const char * unused,void * arg)734 static int __init do_early_param(char *param, char *val,
735 				 const char *unused, void *arg)
736 {
737 	const struct obs_kernel_param *p;
738 
739 	for (p = __setup_start; p < __setup_end; p++) {
740 		if ((p->early && parameq(param, p->str)) ||
741 		    (strcmp(param, "console") == 0 &&
742 		     strcmp(p->str, "earlycon") == 0)
743 		) {
744 			if (p->setup_func(val) != 0)
745 				pr_warn("Malformed early option '%s'\n", param);
746 		}
747 	}
748 	/* We accept everything at this stage. */
749 	return 0;
750 }
751 
parse_early_options(char * cmdline)752 void __init parse_early_options(char *cmdline)
753 {
754 	parse_args("early options", cmdline, NULL, 0, 0, 0, NULL,
755 		   do_early_param);
756 }
757 
758 /* Arch code calls this early on, or if not, just before other parsing. */
parse_early_param(void)759 void __init parse_early_param(void)
760 {
761 	static int done __initdata;
762 	static char tmp_cmdline[COMMAND_LINE_SIZE] __initdata;
763 
764 	if (done)
765 		return;
766 
767 	/* All fall through to do_early_param. */
768 	strscpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);
769 	parse_early_options(tmp_cmdline);
770 	done = 1;
771 }
772 
arch_post_acpi_subsys_init(void)773 void __init __weak arch_post_acpi_subsys_init(void) { }
774 
smp_setup_processor_id(void)775 void __init __weak smp_setup_processor_id(void)
776 {
777 }
778 
779 # if THREAD_SIZE >= PAGE_SIZE
thread_stack_cache_init(void)780 void __init __weak thread_stack_cache_init(void)
781 {
782 }
783 #endif
784 
poking_init(void)785 void __init __weak poking_init(void) { }
786 
pgtable_cache_init(void)787 void __init __weak pgtable_cache_init(void) { }
788 
trap_init(void)789 void __init __weak trap_init(void) { }
790 
791 bool initcall_debug;
792 core_param(initcall_debug, initcall_debug, bool, 0644);
793 
794 #ifdef TRACEPOINTS_ENABLED
795 static void __init initcall_debug_enable(void);
796 #else
initcall_debug_enable(void)797 static inline void initcall_debug_enable(void)
798 {
799 }
800 #endif
801 
802 #ifdef CONFIG_RANDOMIZE_KSTACK_OFFSET
803 DEFINE_STATIC_KEY_MAYBE_RO(CONFIG_RANDOMIZE_KSTACK_OFFSET_DEFAULT,
804 			   randomize_kstack_offset);
805 DEFINE_PER_CPU(u32, kstack_offset);
806 
early_randomize_kstack_offset(char * buf)807 static int __init early_randomize_kstack_offset(char *buf)
808 {
809 	int ret;
810 	bool bool_result;
811 
812 	ret = kstrtobool(buf, &bool_result);
813 	if (ret)
814 		return ret;
815 
816 	if (bool_result)
817 		static_branch_enable(&randomize_kstack_offset);
818 	else
819 		static_branch_disable(&randomize_kstack_offset);
820 	return 0;
821 }
822 early_param("randomize_kstack_offset", early_randomize_kstack_offset);
823 #endif
824 
arch_call_rest_init(void)825 void __init __weak __noreturn arch_call_rest_init(void)
826 {
827 	rest_init();
828 }
829 
print_unknown_bootoptions(void)830 static void __init print_unknown_bootoptions(void)
831 {
832 	char *unknown_options;
833 	char *end;
834 	const char *const *p;
835 	size_t len;
836 
837 	if (panic_later || (!argv_init[1] && !envp_init[2]))
838 		return;
839 
840 	/*
841 	 * Determine how many options we have to print out, plus a space
842 	 * before each
843 	 */
844 	len = 1; /* null terminator */
845 	for (p = &argv_init[1]; *p; p++) {
846 		len++;
847 		len += strlen(*p);
848 	}
849 	for (p = &envp_init[2]; *p; p++) {
850 		len++;
851 		len += strlen(*p);
852 	}
853 
854 	unknown_options = memblock_alloc(len, SMP_CACHE_BYTES);
855 	if (!unknown_options) {
856 		pr_err("%s: Failed to allocate %zu bytes\n",
857 			__func__, len);
858 		return;
859 	}
860 	end = unknown_options;
861 
862 	for (p = &argv_init[1]; *p; p++)
863 		end += sprintf(end, " %s", *p);
864 	for (p = &envp_init[2]; *p; p++)
865 		end += sprintf(end, " %s", *p);
866 
867 	/* Start at unknown_options[1] to skip the initial space */
868 	pr_notice("Unknown kernel command line parameters \"%s\", will be passed to user space.\n",
869 		&unknown_options[1]);
870 	memblock_free(unknown_options, len);
871 }
872 
873 asmlinkage __visible __init __no_sanitize_address __noreturn __no_stack_protector
start_kernel(void)874 void start_kernel(void)
875 {
876 	char *command_line;
877 	char *after_dashes;
878 
879 	set_task_stack_end_magic(&init_task);
880 	smp_setup_processor_id();
881 	debug_objects_early_init();
882 	init_vmlinux_build_id();
883 
884 	cgroup_init_early();
885 
886 	local_irq_disable();
887 	early_boot_irqs_disabled = true;
888 
889 	/*
890 	 * Interrupts are still disabled. Do necessary setups, then
891 	 * enable them.
892 	 */
893 	boot_cpu_init();
894 	page_address_init();
895 	pr_notice("%s", linux_banner);
896 	early_security_init();
897 	setup_arch(&command_line);
898 	setup_boot_config();
899 	setup_command_line(command_line);
900 	setup_nr_cpu_ids();
901 	setup_per_cpu_areas();
902 	smp_prepare_boot_cpu();	/* arch-specific boot-cpu hooks */
903 	boot_cpu_hotplug_init();
904 
905 	pr_notice("Kernel command line: %s\n", saved_command_line);
906 	/* parameters may set static keys */
907 	jump_label_init();
908 	parse_early_param();
909 	after_dashes = parse_args("Booting kernel",
910 				  static_command_line, __start___param,
911 				  __stop___param - __start___param,
912 				  -1, -1, NULL, &unknown_bootoption);
913 	print_unknown_bootoptions();
914 	if (!IS_ERR_OR_NULL(after_dashes))
915 		parse_args("Setting init args", after_dashes, NULL, 0, -1, -1,
916 			   NULL, set_init_arg);
917 	if (extra_init_args)
918 		parse_args("Setting extra init args", extra_init_args,
919 			   NULL, 0, -1, -1, NULL, set_init_arg);
920 
921 	/* Architectural and non-timekeeping rng init, before allocator init */
922 	random_init_early(command_line);
923 
924 	/*
925 	 * These use large bootmem allocations and must precede
926 	 * initalization of page allocator
927 	 */
928 	setup_log_buf(0);
929 	vfs_caches_init_early();
930 	sort_main_extable();
931 	trap_init();
932 	mm_core_init();
933 	poking_init();
934 	ftrace_init();
935 
936 	/* trace_printk can be enabled here */
937 	early_trace_init();
938 
939 	/*
940 	 * Set up the scheduler prior starting any interrupts (such as the
941 	 * timer interrupt). Full topology setup happens at smp_init()
942 	 * time - but meanwhile we still have a functioning scheduler.
943 	 */
944 	sched_init();
945 
946 	if (WARN(!irqs_disabled(),
947 		 "Interrupts were enabled *very* early, fixing it\n"))
948 		local_irq_disable();
949 	radix_tree_init();
950 	maple_tree_init();
951 
952 	/*
953 	 * Set up housekeeping before setting up workqueues to allow the unbound
954 	 * workqueue to take non-housekeeping into account.
955 	 */
956 	housekeeping_init();
957 
958 	/*
959 	 * Allow workqueue creation and work item queueing/cancelling
960 	 * early.  Work item execution depends on kthreads and starts after
961 	 * workqueue_init().
962 	 */
963 	workqueue_init_early();
964 
965 	rcu_init();
966 
967 	/* Trace events are available after this */
968 	trace_init();
969 
970 	if (initcall_debug)
971 		initcall_debug_enable();
972 
973 	context_tracking_init();
974 	/* init some links before init_ISA_irqs() */
975 	early_irq_init();
976 	init_IRQ();
977 	tick_init();
978 	rcu_init_nohz();
979 	init_timers();
980 	srcu_init();
981 	hrtimers_init();
982 	softirq_init();
983 	timekeeping_init();
984 	time_init();
985 
986 	/* This must be after timekeeping is initialized */
987 	random_init();
988 
989 	/* These make use of the fully initialized rng */
990 	kfence_init();
991 	boot_init_stack_canary();
992 
993 	perf_event_init();
994 	profile_init();
995 	call_function_init();
996 	WARN(!irqs_disabled(), "Interrupts were enabled early\n");
997 
998 	early_boot_irqs_disabled = false;
999 	local_irq_enable();
1000 
1001 	kmem_cache_init_late();
1002 
1003 	/*
1004 	 * HACK ALERT! This is early. We're enabling the console before
1005 	 * we've done PCI setups etc, and console_init() must be aware of
1006 	 * this. But we do want output early, in case something goes wrong.
1007 	 */
1008 	console_init();
1009 	if (panic_later)
1010 		panic("Too many boot %s vars at `%s'", panic_later,
1011 		      panic_param);
1012 
1013 	lockdep_init();
1014 
1015 	/*
1016 	 * Need to run this when irqs are enabled, because it wants
1017 	 * to self-test [hard/soft]-irqs on/off lock inversion bugs
1018 	 * too:
1019 	 */
1020 	locking_selftest();
1021 
1022 #ifdef CONFIG_BLK_DEV_INITRD
1023 	if (initrd_start && !initrd_below_start_ok &&
1024 	    page_to_pfn(virt_to_page((void *)initrd_start)) < min_low_pfn) {
1025 		pr_crit("initrd overwritten (0x%08lx < 0x%08lx) - disabling it.\n",
1026 		    page_to_pfn(virt_to_page((void *)initrd_start)),
1027 		    min_low_pfn);
1028 		initrd_start = 0;
1029 	}
1030 #endif
1031 	setup_per_cpu_pageset();
1032 	numa_policy_init();
1033 	acpi_early_init();
1034 	if (late_time_init)
1035 		late_time_init();
1036 	sched_clock_init();
1037 	calibrate_delay();
1038 
1039 	arch_cpu_finalize_init();
1040 
1041 	pid_idr_init();
1042 	anon_vma_init();
1043 #ifdef CONFIG_X86
1044 	if (efi_enabled(EFI_RUNTIME_SERVICES))
1045 		efi_enter_virtual_mode();
1046 #endif
1047 	thread_stack_cache_init();
1048 	cred_init();
1049 	fork_init();
1050 	proc_caches_init();
1051 	uts_ns_init();
1052 	key_init();
1053 	security_init();
1054 	dbg_late_init();
1055 	net_ns_init();
1056 	vfs_caches_init();
1057 	pagecache_init();
1058 	signals_init();
1059 	seq_file_init();
1060 	proc_root_init();
1061 	nsfs_init();
1062 	cpuset_init();
1063 	cgroup_init();
1064 	taskstats_init_early();
1065 	delayacct_init();
1066 
1067 	acpi_subsystem_init();
1068 	arch_post_acpi_subsys_init();
1069 	kcsan_init();
1070 
1071 	/* Do the rest non-__init'ed, we're now alive */
1072 	arch_call_rest_init();
1073 
1074 	/*
1075 	 * Avoid stack canaries in callers of boot_init_stack_canary for gcc-10
1076 	 * and older.
1077 	 */
1078 #if !__has_attribute(__no_stack_protector__)
1079 	prevent_tail_call_optimization();
1080 #endif
1081 }
1082 
1083 /* Call all constructor functions linked into the kernel. */
do_ctors(void)1084 static void __init do_ctors(void)
1085 {
1086 /*
1087  * For UML, the constructors have already been called by the
1088  * normal setup code as it's just a normal ELF binary, so we
1089  * cannot do it again - but we do need CONFIG_CONSTRUCTORS
1090  * even on UML for modules.
1091  */
1092 #if defined(CONFIG_CONSTRUCTORS) && !defined(CONFIG_UML)
1093 	ctor_fn_t *fn = (ctor_fn_t *) __ctors_start;
1094 
1095 	for (; fn < (ctor_fn_t *) __ctors_end; fn++)
1096 		(*fn)();
1097 #endif
1098 }
1099 
1100 #ifdef CONFIG_KALLSYMS
1101 struct blacklist_entry {
1102 	struct list_head next;
1103 	char *buf;
1104 };
1105 
1106 static __initdata_or_module LIST_HEAD(blacklisted_initcalls);
1107 
initcall_blacklist(char * str)1108 static int __init initcall_blacklist(char *str)
1109 {
1110 	char *str_entry;
1111 	struct blacklist_entry *entry;
1112 
1113 	/* str argument is a comma-separated list of functions */
1114 	do {
1115 		str_entry = strsep(&str, ",");
1116 		if (str_entry) {
1117 			pr_debug("blacklisting initcall %s\n", str_entry);
1118 			entry = memblock_alloc(sizeof(*entry),
1119 					       SMP_CACHE_BYTES);
1120 			if (!entry)
1121 				panic("%s: Failed to allocate %zu bytes\n",
1122 				      __func__, sizeof(*entry));
1123 			entry->buf = memblock_alloc(strlen(str_entry) + 1,
1124 						    SMP_CACHE_BYTES);
1125 			if (!entry->buf)
1126 				panic("%s: Failed to allocate %zu bytes\n",
1127 				      __func__, strlen(str_entry) + 1);
1128 			strcpy(entry->buf, str_entry);
1129 			list_add(&entry->next, &blacklisted_initcalls);
1130 		}
1131 	} while (str_entry);
1132 
1133 	return 1;
1134 }
1135 
initcall_blacklisted(initcall_t fn)1136 static bool __init_or_module initcall_blacklisted(initcall_t fn)
1137 {
1138 	struct blacklist_entry *entry;
1139 	char fn_name[KSYM_SYMBOL_LEN];
1140 	unsigned long addr;
1141 
1142 	if (list_empty(&blacklisted_initcalls))
1143 		return false;
1144 
1145 	addr = (unsigned long) dereference_function_descriptor(fn);
1146 	sprint_symbol_no_offset(fn_name, addr);
1147 
1148 	/*
1149 	 * fn will be "function_name [module_name]" where [module_name] is not
1150 	 * displayed for built-in init functions.  Strip off the [module_name].
1151 	 */
1152 	strreplace(fn_name, ' ', '\0');
1153 
1154 	list_for_each_entry(entry, &blacklisted_initcalls, next) {
1155 		if (!strcmp(fn_name, entry->buf)) {
1156 			pr_debug("initcall %s blacklisted\n", fn_name);
1157 			return true;
1158 		}
1159 	}
1160 
1161 	return false;
1162 }
1163 #else
initcall_blacklist(char * str)1164 static int __init initcall_blacklist(char *str)
1165 {
1166 	pr_warn("initcall_blacklist requires CONFIG_KALLSYMS\n");
1167 	return 0;
1168 }
1169 
initcall_blacklisted(initcall_t fn)1170 static bool __init_or_module initcall_blacklisted(initcall_t fn)
1171 {
1172 	return false;
1173 }
1174 #endif
1175 __setup("initcall_blacklist=", initcall_blacklist);
1176 
1177 static __init_or_module void
trace_initcall_start_cb(void * data,initcall_t fn)1178 trace_initcall_start_cb(void *data, initcall_t fn)
1179 {
1180 	ktime_t *calltime = data;
1181 
1182 	printk(KERN_DEBUG "calling  %pS @ %i\n", fn, task_pid_nr(current));
1183 	*calltime = ktime_get();
1184 }
1185 
1186 static __init_or_module void
trace_initcall_finish_cb(void * data,initcall_t fn,int ret)1187 trace_initcall_finish_cb(void *data, initcall_t fn, int ret)
1188 {
1189 	ktime_t rettime, *calltime = data;
1190 
1191 	rettime = ktime_get();
1192 	printk(KERN_DEBUG "initcall %pS returned %d after %lld usecs\n",
1193 		 fn, ret, (unsigned long long)ktime_us_delta(rettime, *calltime));
1194 }
1195 
1196 static ktime_t initcall_calltime;
1197 
1198 #ifdef TRACEPOINTS_ENABLED
initcall_debug_enable(void)1199 static void __init initcall_debug_enable(void)
1200 {
1201 	int ret;
1202 
1203 	ret = register_trace_initcall_start(trace_initcall_start_cb,
1204 					    &initcall_calltime);
1205 	ret |= register_trace_initcall_finish(trace_initcall_finish_cb,
1206 					      &initcall_calltime);
1207 	WARN(ret, "Failed to register initcall tracepoints\n");
1208 }
1209 # define do_trace_initcall_start	trace_initcall_start
1210 # define do_trace_initcall_finish	trace_initcall_finish
1211 #else
do_trace_initcall_start(initcall_t fn)1212 static inline void do_trace_initcall_start(initcall_t fn)
1213 {
1214 	if (!initcall_debug)
1215 		return;
1216 	trace_initcall_start_cb(&initcall_calltime, fn);
1217 }
do_trace_initcall_finish(initcall_t fn,int ret)1218 static inline void do_trace_initcall_finish(initcall_t fn, int ret)
1219 {
1220 	if (!initcall_debug)
1221 		return;
1222 	trace_initcall_finish_cb(&initcall_calltime, fn, ret);
1223 }
1224 #endif /* !TRACEPOINTS_ENABLED */
1225 
do_one_initcall(initcall_t fn)1226 int __init_or_module do_one_initcall(initcall_t fn)
1227 {
1228 	int count = preempt_count();
1229 	char msgbuf[64];
1230 	int ret;
1231 
1232 	if (initcall_blacklisted(fn))
1233 		return -EPERM;
1234 
1235 	do_trace_initcall_start(fn);
1236 	ret = fn();
1237 	do_trace_initcall_finish(fn, ret);
1238 
1239 	msgbuf[0] = 0;
1240 
1241 	if (preempt_count() != count) {
1242 		sprintf(msgbuf, "preemption imbalance ");
1243 		preempt_count_set(count);
1244 	}
1245 	if (irqs_disabled()) {
1246 		strlcat(msgbuf, "disabled interrupts ", sizeof(msgbuf));
1247 		local_irq_enable();
1248 	}
1249 	WARN(msgbuf[0], "initcall %pS returned with %s\n", fn, msgbuf);
1250 
1251 	add_latent_entropy();
1252 	return ret;
1253 }
1254 
1255 
1256 static initcall_entry_t *initcall_levels[] __initdata = {
1257 	__initcall0_start,
1258 	__initcall1_start,
1259 	__initcall2_start,
1260 	__initcall3_start,
1261 	__initcall4_start,
1262 	__initcall5_start,
1263 	__initcall6_start,
1264 	__initcall7_start,
1265 	__initcall_end,
1266 };
1267 
1268 /* Keep these in sync with initcalls in include/linux/init.h */
1269 static const char *initcall_level_names[] __initdata = {
1270 	"pure",
1271 	"core",
1272 	"postcore",
1273 	"arch",
1274 	"subsys",
1275 	"fs",
1276 	"device",
1277 	"late",
1278 };
1279 
ignore_unknown_bootoption(char * param,char * val,const char * unused,void * arg)1280 static int __init ignore_unknown_bootoption(char *param, char *val,
1281 			       const char *unused, void *arg)
1282 {
1283 	return 0;
1284 }
1285 
do_initcall_level(int level,char * command_line)1286 static void __init do_initcall_level(int level, char *command_line)
1287 {
1288 	initcall_entry_t *fn;
1289 
1290 	parse_args(initcall_level_names[level],
1291 		   command_line, __start___param,
1292 		   __stop___param - __start___param,
1293 		   level, level,
1294 		   NULL, ignore_unknown_bootoption);
1295 
1296 	trace_initcall_level(initcall_level_names[level]);
1297 	for (fn = initcall_levels[level]; fn < initcall_levels[level+1]; fn++)
1298 		do_one_initcall(initcall_from_entry(fn));
1299 }
1300 
do_initcalls(void)1301 static void __init do_initcalls(void)
1302 {
1303 	int level;
1304 	size_t len = saved_command_line_len + 1;
1305 	char *command_line;
1306 
1307 	command_line = kzalloc(len, GFP_KERNEL);
1308 	if (!command_line)
1309 		panic("%s: Failed to allocate %zu bytes\n", __func__, len);
1310 
1311 	for (level = 0; level < ARRAY_SIZE(initcall_levels) - 1; level++) {
1312 		/* Parser modifies command_line, restore it each time */
1313 		strcpy(command_line, saved_command_line);
1314 		do_initcall_level(level, command_line);
1315 	}
1316 
1317 	kfree(command_line);
1318 }
1319 
1320 /*
1321  * Ok, the machine is now initialized. None of the devices
1322  * have been touched yet, but the CPU subsystem is up and
1323  * running, and memory and process management works.
1324  *
1325  * Now we can finally start doing some real work..
1326  */
do_basic_setup(void)1327 static void __init do_basic_setup(void)
1328 {
1329 	cpuset_init_smp();
1330 	driver_init();
1331 	init_irq_proc();
1332 	do_ctors();
1333 	do_initcalls();
1334 }
1335 
do_pre_smp_initcalls(void)1336 static void __init do_pre_smp_initcalls(void)
1337 {
1338 	initcall_entry_t *fn;
1339 
1340 	trace_initcall_level("early");
1341 	for (fn = __initcall_start; fn < __initcall0_start; fn++)
1342 		do_one_initcall(initcall_from_entry(fn));
1343 }
1344 
run_init_process(const char * init_filename)1345 static int run_init_process(const char *init_filename)
1346 {
1347 	const char *const *p;
1348 
1349 	argv_init[0] = init_filename;
1350 	pr_info("Run %s as init process\n", init_filename);
1351 	pr_debug("  with arguments:\n");
1352 	for (p = argv_init; *p; p++)
1353 		pr_debug("    %s\n", *p);
1354 	pr_debug("  with environment:\n");
1355 	for (p = envp_init; *p; p++)
1356 		pr_debug("    %s\n", *p);
1357 	return kernel_execve(init_filename, argv_init, envp_init);
1358 }
1359 
try_to_run_init_process(const char * init_filename)1360 static int try_to_run_init_process(const char *init_filename)
1361 {
1362 	int ret;
1363 
1364 	ret = run_init_process(init_filename);
1365 
1366 	if (ret && ret != -ENOENT) {
1367 		pr_err("Starting init: %s exists but couldn't execute it (error %d)\n",
1368 		       init_filename, ret);
1369 	}
1370 
1371 	return ret;
1372 }
1373 
1374 static noinline void __init kernel_init_freeable(void);
1375 
1376 #if defined(CONFIG_STRICT_KERNEL_RWX) || defined(CONFIG_STRICT_MODULE_RWX)
1377 bool rodata_enabled __ro_after_init = true;
1378 
1379 #ifndef arch_parse_debug_rodata
arch_parse_debug_rodata(char * str)1380 static inline bool arch_parse_debug_rodata(char *str) { return false; }
1381 #endif
1382 
set_debug_rodata(char * str)1383 static int __init set_debug_rodata(char *str)
1384 {
1385 	if (arch_parse_debug_rodata(str))
1386 		return 0;
1387 
1388 	if (str && !strcmp(str, "on"))
1389 		rodata_enabled = true;
1390 	else if (str && !strcmp(str, "off"))
1391 		rodata_enabled = false;
1392 	else
1393 		pr_warn("Invalid option string for rodata: '%s'\n", str);
1394 	return 0;
1395 }
1396 early_param("rodata", set_debug_rodata);
1397 #endif
1398 
1399 #ifdef CONFIG_STRICT_KERNEL_RWX
mark_readonly(void)1400 static void mark_readonly(void)
1401 {
1402 	if (rodata_enabled) {
1403 		/*
1404 		 * load_module() results in W+X mappings, which are cleaned
1405 		 * up with call_rcu().  Let's make sure that queued work is
1406 		 * flushed so that we don't hit false positives looking for
1407 		 * insecure pages which are W+X.
1408 		 */
1409 		rcu_barrier();
1410 		mark_rodata_ro();
1411 		rodata_test();
1412 	} else
1413 		pr_info("Kernel memory protection disabled.\n");
1414 }
1415 #elif defined(CONFIG_ARCH_HAS_STRICT_KERNEL_RWX)
mark_readonly(void)1416 static inline void mark_readonly(void)
1417 {
1418 	pr_warn("Kernel memory protection not selected by kernel config.\n");
1419 }
1420 #else
mark_readonly(void)1421 static inline void mark_readonly(void)
1422 {
1423 	pr_warn("This architecture does not have kernel memory protection.\n");
1424 }
1425 #endif
1426 
free_initmem(void)1427 void __weak free_initmem(void)
1428 {
1429 	free_initmem_default(POISON_FREE_INITMEM);
1430 }
1431 
kernel_init(void * unused)1432 static int __ref kernel_init(void *unused)
1433 {
1434 	int ret;
1435 
1436 	/*
1437 	 * Wait until kthreadd is all set-up.
1438 	 */
1439 	wait_for_completion(&kthreadd_done);
1440 
1441 	kernel_init_freeable();
1442 	/* need to finish all async __init code before freeing the memory */
1443 	async_synchronize_full();
1444 
1445 	system_state = SYSTEM_FREEING_INITMEM;
1446 	kprobe_free_init_mem();
1447 	ftrace_free_init_mem();
1448 	kgdb_free_init_mem();
1449 	exit_boot_config();
1450 	free_initmem();
1451 	mark_readonly();
1452 
1453 	/*
1454 	 * Kernel mappings are now finalized - update the userspace page-table
1455 	 * to finalize PTI.
1456 	 */
1457 	pti_finalize();
1458 
1459 	system_state = SYSTEM_RUNNING;
1460 	numa_default_policy();
1461 
1462 	rcu_end_inkernel_boot();
1463 
1464 	do_sysctl_args();
1465 
1466 	if (ramdisk_execute_command) {
1467 		ret = run_init_process(ramdisk_execute_command);
1468 		if (!ret)
1469 			return 0;
1470 		pr_err("Failed to execute %s (error %d)\n",
1471 		       ramdisk_execute_command, ret);
1472 	}
1473 
1474 	/*
1475 	 * We try each of these until one succeeds.
1476 	 *
1477 	 * The Bourne shell can be used instead of init if we are
1478 	 * trying to recover a really broken machine.
1479 	 */
1480 	if (execute_command) {
1481 		ret = run_init_process(execute_command);
1482 		if (!ret)
1483 			return 0;
1484 		panic("Requested init %s failed (error %d).",
1485 		      execute_command, ret);
1486 	}
1487 
1488 	if (CONFIG_DEFAULT_INIT[0] != '\0') {
1489 		ret = run_init_process(CONFIG_DEFAULT_INIT);
1490 		if (ret)
1491 			pr_err("Default init %s failed (error %d)\n",
1492 			       CONFIG_DEFAULT_INIT, ret);
1493 		else
1494 			return 0;
1495 	}
1496 
1497 	if (!try_to_run_init_process("/sbin/init") ||
1498 	    !try_to_run_init_process("/etc/init") ||
1499 	    !try_to_run_init_process("/bin/init") ||
1500 	    !try_to_run_init_process("/bin/sh"))
1501 		return 0;
1502 
1503 	panic("No working init found.  Try passing init= option to kernel. "
1504 	      "See Linux Documentation/admin-guide/init.rst for guidance.");
1505 }
1506 
1507 /* Open /dev/console, for stdin/stdout/stderr, this should never fail */
console_on_rootfs(void)1508 void __init console_on_rootfs(void)
1509 {
1510 	struct file *file = filp_open("/dev/console", O_RDWR, 0);
1511 
1512 	if (IS_ERR(file)) {
1513 		pr_err("Warning: unable to open an initial console.\n");
1514 		return;
1515 	}
1516 	init_dup(file);
1517 	init_dup(file);
1518 	init_dup(file);
1519 	fput(file);
1520 }
1521 
kernel_init_freeable(void)1522 static noinline void __init kernel_init_freeable(void)
1523 {
1524 	/* Now the scheduler is fully set up and can do blocking allocations */
1525 	gfp_allowed_mask = __GFP_BITS_MASK;
1526 
1527 	/*
1528 	 * init can allocate pages on any node
1529 	 */
1530 	set_mems_allowed(node_states[N_MEMORY]);
1531 
1532 	cad_pid = get_pid(task_pid(current));
1533 
1534 	smp_prepare_cpus(setup_max_cpus);
1535 
1536 	workqueue_init();
1537 
1538 	init_mm_internals();
1539 
1540 	rcu_init_tasks_generic();
1541 	do_pre_smp_initcalls();
1542 	lockup_detector_init();
1543 
1544 	smp_init();
1545 	sched_init_smp();
1546 
1547 	workqueue_init_topology();
1548 	padata_init();
1549 	page_alloc_init_late();
1550 
1551 	do_basic_setup();
1552 
1553 	kunit_run_all_tests();
1554 
1555 	wait_for_initramfs();
1556 	console_on_rootfs();
1557 
1558 	/*
1559 	 * check if there is an early userspace init.  If yes, let it do all
1560 	 * the work
1561 	 */
1562 	if (init_eaccess(ramdisk_execute_command) != 0) {
1563 		ramdisk_execute_command = NULL;
1564 		prepare_namespace();
1565 	}
1566 
1567 	/*
1568 	 * Ok, we have completed the initial bootup, and
1569 	 * we're essentially up and running. Get rid of the
1570 	 * initmem segments and start the user-mode stuff..
1571 	 *
1572 	 * rootfs is available now, try loading the public keys
1573 	 * and default modules
1574 	 */
1575 
1576 	integrity_load_keys();
1577 }
1578