1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * linux/init/main.c
4 *
5 * Copyright (C) 1991, 1992 Linus Torvalds
6 *
7 * GK 2/5/95 - Changed to support mounting root fs via NFS
8 * Added initrd & change_root: Werner Almesberger & Hans Lermen, Feb '96
9 * Moan early if gcc is old, avoiding bogus kernels - Paul Gortmaker, May '96
10 * Simplified starting of init: Michael A. Griffith <grif@acm.org>
11 */
12
13 #define DEBUG /* Enable initcall_debug */
14
15 #include <linux/types.h>
16 #include <linux/extable.h>
17 #include <linux/module.h>
18 #include <linux/proc_fs.h>
19 #include <linux/binfmts.h>
20 #include <linux/kernel.h>
21 #include <linux/syscalls.h>
22 #include <linux/stackprotector.h>
23 #include <linux/string.h>
24 #include <linux/ctype.h>
25 #include <linux/delay.h>
26 #include <linux/ioport.h>
27 #include <linux/init.h>
28 #include <linux/initrd.h>
29 #include <linux/memblock.h>
30 #include <linux/acpi.h>
31 #include <linux/bootconfig.h>
32 #include <linux/console.h>
33 #include <linux/nmi.h>
34 #include <linux/percpu.h>
35 #include <linux/kmod.h>
36 #include <linux/kprobes.h>
37 #include <linux/kmsan.h>
38 #include <linux/vmalloc.h>
39 #include <linux/kernel_stat.h>
40 #include <linux/start_kernel.h>
41 #include <linux/security.h>
42 #include <linux/smp.h>
43 #include <linux/profile.h>
44 #include <linux/kfence.h>
45 #include <linux/rcupdate.h>
46 #include <linux/srcu.h>
47 #include <linux/moduleparam.h>
48 #include <linux/kallsyms.h>
49 #include <linux/buildid.h>
50 #include <linux/writeback.h>
51 #include <linux/cpu.h>
52 #include <linux/cpuset.h>
53 #include <linux/cgroup.h>
54 #include <linux/efi.h>
55 #include <linux/tick.h>
56 #include <linux/sched/isolation.h>
57 #include <linux/interrupt.h>
58 #include <linux/taskstats_kern.h>
59 #include <linux/delayacct.h>
60 #include <linux/unistd.h>
61 #include <linux/utsname.h>
62 #include <linux/rmap.h>
63 #include <linux/mempolicy.h>
64 #include <linux/key.h>
65 #include <linux/debug_locks.h>
66 #include <linux/debugobjects.h>
67 #include <linux/lockdep.h>
68 #include <linux/kmemleak.h>
69 #include <linux/padata.h>
70 #include <linux/pid_namespace.h>
71 #include <linux/device/driver.h>
72 #include <linux/kthread.h>
73 #include <linux/sched.h>
74 #include <linux/sched/init.h>
75 #include <linux/signal.h>
76 #include <linux/idr.h>
77 #include <linux/kgdb.h>
78 #include <linux/ftrace.h>
79 #include <linux/async.h>
80 #include <linux/shmem_fs.h>
81 #include <linux/slab.h>
82 #include <linux/perf_event.h>
83 #include <linux/ptrace.h>
84 #include <linux/pti.h>
85 #include <linux/blkdev.h>
86 #include <linux/sched/clock.h>
87 #include <linux/sched/task.h>
88 #include <linux/sched/task_stack.h>
89 #include <linux/context_tracking.h>
90 #include <linux/random.h>
91 #include <linux/moduleloader.h>
92 #include <linux/list.h>
93 #include <linux/integrity.h>
94 #include <linux/proc_ns.h>
95 #include <linux/io.h>
96 #include <linux/cache.h>
97 #include <linux/rodata_test.h>
98 #include <linux/jump_label.h>
99 #include <linux/kcsan.h>
100 #include <linux/init_syscalls.h>
101 #include <linux/stackdepot.h>
102 #include <linux/randomize_kstack.h>
103 #include <linux/pidfs.h>
104 #include <linux/ptdump.h>
105 #include <net/net_namespace.h>
106
107 #include <asm/io.h>
108 #include <asm/setup.h>
109 #include <asm/sections.h>
110 #include <asm/cacheflush.h>
111
112 #define CREATE_TRACE_POINTS
113 #include <trace/events/initcall.h>
114
115 #include <kunit/test.h>
116
117 static int kernel_init(void *);
118
119 /*
120 * Debug helper: via this flag we know that we are in 'early bootup code'
121 * where only the boot processor is running with IRQ disabled. This means
122 * two things - IRQ must not be enabled before the flag is cleared and some
123 * operations which are not allowed with IRQ disabled are allowed while the
124 * flag is set.
125 */
126 bool early_boot_irqs_disabled __read_mostly;
127
128 enum system_states system_state __read_mostly;
129 EXPORT_SYMBOL(system_state);
130
131 /*
132 * Boot command-line arguments
133 */
134 #define MAX_INIT_ARGS CONFIG_INIT_ENV_ARG_LIMIT
135 #define MAX_INIT_ENVS CONFIG_INIT_ENV_ARG_LIMIT
136
137 /* Default late time init is NULL. archs can override this later. */
138 void (*__initdata late_time_init)(void);
139
140 /* Untouched command line saved by arch-specific code. */
141 char __initdata boot_command_line[COMMAND_LINE_SIZE];
142 /* Untouched saved command line (eg. for /proc) */
143 char *saved_command_line __ro_after_init;
144 unsigned int saved_command_line_len __ro_after_init;
145 /* Command line for parameter parsing */
146 static char *static_command_line;
147 /* Untouched extra command line */
148 static char *extra_command_line;
149 /* Extra init arguments */
150 static char *extra_init_args;
151
152 #ifdef CONFIG_BOOT_CONFIG
153 /* Is bootconfig on command line? */
154 static bool bootconfig_found;
155 static size_t initargs_offs;
156 #else
157 # define bootconfig_found false
158 # define initargs_offs 0
159 #endif
160
161 static char *execute_command;
162 static char *ramdisk_execute_command = "/init";
163
164 /*
165 * Used to generate warnings if static_key manipulation functions are used
166 * before jump_label_init is called.
167 */
168 bool static_key_initialized __read_mostly;
169 EXPORT_SYMBOL_GPL(static_key_initialized);
170
171 /*
172 * If set, this is an indication to the drivers that reset the underlying
173 * device before going ahead with the initialization otherwise driver might
174 * rely on the BIOS and skip the reset operation.
175 *
176 * This is useful if kernel is booting in an unreliable environment.
177 * For ex. kdump situation where previous kernel has crashed, BIOS has been
178 * skipped and devices will be in unknown state.
179 */
180 unsigned int reset_devices;
181 EXPORT_SYMBOL(reset_devices);
182
set_reset_devices(char * str)183 static int __init set_reset_devices(char *str)
184 {
185 reset_devices = 1;
186 return 1;
187 }
188
189 __setup("reset_devices", set_reset_devices);
190
191 static const char *argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
192 const char *envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, };
193 static const char *panic_later, *panic_param;
194
obsolete_checksetup(char * line)195 static bool __init obsolete_checksetup(char *line)
196 {
197 const struct obs_kernel_param *p;
198 bool had_early_param = false;
199
200 p = __setup_start;
201 do {
202 int n = strlen(p->str);
203 if (parameqn(line, p->str, n)) {
204 if (p->early) {
205 /* Already done in parse_early_param?
206 * (Needs exact match on param part).
207 * Keep iterating, as we can have early
208 * params and __setups of same names 8( */
209 if (line[n] == '\0' || line[n] == '=')
210 had_early_param = true;
211 } else if (!p->setup_func) {
212 pr_warn("Parameter %s is obsolete, ignored\n",
213 p->str);
214 return true;
215 } else if (p->setup_func(line + n))
216 return true;
217 }
218 p++;
219 } while (p < __setup_end);
220
221 return had_early_param;
222 }
223
224 /*
225 * This should be approx 2 Bo*oMips to start (note initial shift), and will
226 * still work even if initially too large, it will just take slightly longer
227 */
228 unsigned long loops_per_jiffy = (1<<12);
229 EXPORT_SYMBOL(loops_per_jiffy);
230
debug_kernel(char * str)231 static int __init debug_kernel(char *str)
232 {
233 console_loglevel = CONSOLE_LOGLEVEL_DEBUG;
234 return 0;
235 }
236
quiet_kernel(char * str)237 static int __init quiet_kernel(char *str)
238 {
239 console_loglevel = CONSOLE_LOGLEVEL_QUIET;
240 return 0;
241 }
242
243 early_param("debug", debug_kernel);
244 early_param("quiet", quiet_kernel);
245
loglevel(char * str)246 static int __init loglevel(char *str)
247 {
248 int newlevel;
249
250 /*
251 * Only update loglevel value when a correct setting was passed,
252 * to prevent blind crashes (when loglevel being set to 0) that
253 * are quite hard to debug
254 */
255 if (get_option(&str, &newlevel)) {
256 console_loglevel = newlevel;
257 return 0;
258 }
259
260 return -EINVAL;
261 }
262
263 early_param("loglevel", loglevel);
264
265 #ifdef CONFIG_BLK_DEV_INITRD
get_boot_config_from_initrd(size_t * _size)266 static void * __init get_boot_config_from_initrd(size_t *_size)
267 {
268 u32 size, csum;
269 char *data;
270 u32 *hdr;
271 int i;
272
273 if (!initrd_end)
274 return NULL;
275
276 data = (char *)initrd_end - BOOTCONFIG_MAGIC_LEN;
277 /*
278 * Since Grub may align the size of initrd to 4, we must
279 * check the preceding 3 bytes as well.
280 */
281 for (i = 0; i < 4; i++) {
282 if (!memcmp(data, BOOTCONFIG_MAGIC, BOOTCONFIG_MAGIC_LEN))
283 goto found;
284 data--;
285 }
286 return NULL;
287
288 found:
289 hdr = (u32 *)(data - 8);
290 size = le32_to_cpu(hdr[0]);
291 csum = le32_to_cpu(hdr[1]);
292
293 data = ((void *)hdr) - size;
294 if ((unsigned long)data < initrd_start) {
295 pr_err("bootconfig size %d is greater than initrd size %ld\n",
296 size, initrd_end - initrd_start);
297 return NULL;
298 }
299
300 if (xbc_calc_checksum(data, size) != csum) {
301 pr_err("bootconfig checksum failed\n");
302 return NULL;
303 }
304
305 /* Remove bootconfig from initramfs/initrd */
306 initrd_end = (unsigned long)data;
307 if (_size)
308 *_size = size;
309
310 return data;
311 }
312 #else
get_boot_config_from_initrd(size_t * _size)313 static void * __init get_boot_config_from_initrd(size_t *_size)
314 {
315 return NULL;
316 }
317 #endif
318
319 #ifdef CONFIG_BOOT_CONFIG
320
321 static char xbc_namebuf[XBC_KEYLEN_MAX] __initdata;
322
323 #define rest(dst, end) ((end) > (dst) ? (end) - (dst) : 0)
324
xbc_snprint_cmdline(char * buf,size_t size,struct xbc_node * root)325 static int __init xbc_snprint_cmdline(char *buf, size_t size,
326 struct xbc_node *root)
327 {
328 struct xbc_node *knode, *vnode;
329 char *end = buf + size;
330 const char *val;
331 int ret;
332
333 xbc_node_for_each_key_value(root, knode, val) {
334 ret = xbc_node_compose_key_after(root, knode,
335 xbc_namebuf, XBC_KEYLEN_MAX);
336 if (ret < 0)
337 return ret;
338
339 vnode = xbc_node_get_child(knode);
340 if (!vnode) {
341 ret = snprintf(buf, rest(buf, end), "%s ", xbc_namebuf);
342 if (ret < 0)
343 return ret;
344 buf += ret;
345 continue;
346 }
347 xbc_array_for_each_value(vnode, val) {
348 ret = snprintf(buf, rest(buf, end), "%s=\"%s\" ",
349 xbc_namebuf, val);
350 if (ret < 0)
351 return ret;
352 buf += ret;
353 }
354 }
355
356 return buf - (end - size);
357 }
358 #undef rest
359
360 /* Make an extra command line under given key word */
xbc_make_cmdline(const char * key)361 static char * __init xbc_make_cmdline(const char *key)
362 {
363 struct xbc_node *root;
364 char *new_cmdline;
365 int ret, len = 0;
366
367 root = xbc_find_node(key);
368 if (!root)
369 return NULL;
370
371 /* Count required buffer size */
372 len = xbc_snprint_cmdline(NULL, 0, root);
373 if (len <= 0)
374 return NULL;
375
376 new_cmdline = memblock_alloc(len + 1, SMP_CACHE_BYTES);
377 if (!new_cmdline) {
378 pr_err("Failed to allocate memory for extra kernel cmdline.\n");
379 return NULL;
380 }
381
382 ret = xbc_snprint_cmdline(new_cmdline, len + 1, root);
383 if (ret < 0 || ret > len) {
384 pr_err("Failed to print extra kernel cmdline.\n");
385 memblock_free(new_cmdline, len + 1);
386 return NULL;
387 }
388
389 return new_cmdline;
390 }
391
bootconfig_params(char * param,char * val,const char * unused,void * arg)392 static int __init bootconfig_params(char *param, char *val,
393 const char *unused, void *arg)
394 {
395 if (strcmp(param, "bootconfig") == 0) {
396 bootconfig_found = true;
397 }
398 return 0;
399 }
400
warn_bootconfig(char * str)401 static int __init warn_bootconfig(char *str)
402 {
403 /* The 'bootconfig' has been handled by bootconfig_params(). */
404 return 0;
405 }
406
setup_boot_config(void)407 static void __init setup_boot_config(void)
408 {
409 static char tmp_cmdline[COMMAND_LINE_SIZE] __initdata;
410 const char *msg, *data;
411 int pos, ret;
412 size_t size;
413 char *err;
414
415 /* Cut out the bootconfig data even if we have no bootconfig option */
416 data = get_boot_config_from_initrd(&size);
417 /* If there is no bootconfig in initrd, try embedded one. */
418 if (!data)
419 data = xbc_get_embedded_bootconfig(&size);
420
421 strscpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);
422 err = parse_args("bootconfig", tmp_cmdline, NULL, 0, 0, 0, NULL,
423 bootconfig_params);
424
425 if (IS_ERR(err) || !(bootconfig_found || IS_ENABLED(CONFIG_BOOT_CONFIG_FORCE)))
426 return;
427
428 /* parse_args() stops at the next param of '--' and returns an address */
429 if (err)
430 initargs_offs = err - tmp_cmdline;
431
432 if (!data) {
433 /* If user intended to use bootconfig, show an error level message */
434 if (bootconfig_found)
435 pr_err("'bootconfig' found on command line, but no bootconfig found\n");
436 else
437 pr_info("No bootconfig data provided, so skipping bootconfig");
438 return;
439 }
440
441 if (size >= XBC_DATA_MAX) {
442 pr_err("bootconfig size %ld greater than max size %d\n",
443 (long)size, XBC_DATA_MAX);
444 return;
445 }
446
447 ret = xbc_init(data, size, &msg, &pos);
448 if (ret < 0) {
449 if (pos < 0)
450 pr_err("Failed to init bootconfig: %s.\n", msg);
451 else
452 pr_err("Failed to parse bootconfig: %s at %d.\n",
453 msg, pos);
454 } else {
455 xbc_get_info(&ret, NULL);
456 pr_info("Load bootconfig: %ld bytes %d nodes\n", (long)size, ret);
457 /* keys starting with "kernel." are passed via cmdline */
458 extra_command_line = xbc_make_cmdline("kernel");
459 /* Also, "init." keys are init arguments */
460 extra_init_args = xbc_make_cmdline("init");
461 }
462 return;
463 }
464
exit_boot_config(void)465 static void __init exit_boot_config(void)
466 {
467 xbc_exit();
468 }
469
470 #else /* !CONFIG_BOOT_CONFIG */
471
setup_boot_config(void)472 static void __init setup_boot_config(void)
473 {
474 /* Remove bootconfig data from initrd */
475 get_boot_config_from_initrd(NULL);
476 }
477
warn_bootconfig(char * str)478 static int __init warn_bootconfig(char *str)
479 {
480 pr_warn("WARNING: 'bootconfig' found on the kernel command line but CONFIG_BOOT_CONFIG is not set.\n");
481 return 0;
482 }
483
484 #define exit_boot_config() do {} while (0)
485
486 #endif /* CONFIG_BOOT_CONFIG */
487
488 early_param("bootconfig", warn_bootconfig);
489
cmdline_has_extra_options(void)490 bool __init cmdline_has_extra_options(void)
491 {
492 return extra_command_line || extra_init_args;
493 }
494
495 /* Change NUL term back to "=", to make "param" the whole string. */
repair_env_string(char * param,char * val)496 static void __init repair_env_string(char *param, char *val)
497 {
498 if (val) {
499 /* param=val or param="val"? */
500 if (val == param+strlen(param)+1)
501 val[-1] = '=';
502 else if (val == param+strlen(param)+2) {
503 val[-2] = '=';
504 memmove(val-1, val, strlen(val)+1);
505 } else
506 BUG();
507 }
508 }
509
510 /* Anything after -- gets handed straight to init. */
set_init_arg(char * param,char * val,const char * unused,void * arg)511 static int __init set_init_arg(char *param, char *val,
512 const char *unused, void *arg)
513 {
514 unsigned int i;
515
516 if (panic_later)
517 return 0;
518
519 repair_env_string(param, val);
520
521 for (i = 0; argv_init[i]; i++) {
522 if (i == MAX_INIT_ARGS) {
523 panic_later = "init";
524 panic_param = param;
525 return 0;
526 }
527 }
528 argv_init[i] = param;
529 return 0;
530 }
531
532 /*
533 * Unknown boot options get handed to init, unless they look like
534 * unused parameters (modprobe will find them in /proc/cmdline).
535 */
unknown_bootoption(char * param,char * val,const char * unused,void * arg)536 static int __init unknown_bootoption(char *param, char *val,
537 const char *unused, void *arg)
538 {
539 size_t len = strlen(param);
540
541 /* Handle params aliased to sysctls */
542 if (sysctl_is_alias(param))
543 return 0;
544
545 repair_env_string(param, val);
546
547 /* Handle obsolete-style parameters */
548 if (obsolete_checksetup(param))
549 return 0;
550
551 /* Unused module parameter. */
552 if (strnchr(param, len, '.'))
553 return 0;
554
555 if (panic_later)
556 return 0;
557
558 if (val) {
559 /* Environment option */
560 unsigned int i;
561 for (i = 0; envp_init[i]; i++) {
562 if (i == MAX_INIT_ENVS) {
563 panic_later = "env";
564 panic_param = param;
565 }
566 if (!strncmp(param, envp_init[i], len+1))
567 break;
568 }
569 envp_init[i] = param;
570 } else {
571 /* Command line option */
572 unsigned int i;
573 for (i = 0; argv_init[i]; i++) {
574 if (i == MAX_INIT_ARGS) {
575 panic_later = "init";
576 panic_param = param;
577 }
578 }
579 argv_init[i] = param;
580 }
581 return 0;
582 }
583
init_setup(char * str)584 static int __init init_setup(char *str)
585 {
586 unsigned int i;
587
588 execute_command = str;
589 /*
590 * In case LILO is going to boot us with default command line,
591 * it prepends "auto" before the whole cmdline which makes
592 * the shell think it should execute a script with such name.
593 * So we ignore all arguments entered _before_ init=... [MJ]
594 */
595 for (i = 1; i < MAX_INIT_ARGS; i++)
596 argv_init[i] = NULL;
597 return 1;
598 }
599 __setup("init=", init_setup);
600
rdinit_setup(char * str)601 static int __init rdinit_setup(char *str)
602 {
603 unsigned int i;
604
605 ramdisk_execute_command = str;
606 /* See "auto" comment in init_setup */
607 for (i = 1; i < MAX_INIT_ARGS; i++)
608 argv_init[i] = NULL;
609 return 1;
610 }
611 __setup("rdinit=", rdinit_setup);
612
613 #ifndef CONFIG_SMP
setup_nr_cpu_ids(void)614 static inline void setup_nr_cpu_ids(void) { }
smp_prepare_cpus(unsigned int maxcpus)615 static inline void smp_prepare_cpus(unsigned int maxcpus) { }
616 #endif
617
618 /*
619 * We need to store the untouched command line for future reference.
620 * We also need to store the touched command line since the parameter
621 * parsing is performed in place, and we should allow a component to
622 * store reference of name/value for future reference.
623 */
setup_command_line(char * command_line)624 static void __init setup_command_line(char *command_line)
625 {
626 size_t len, xlen = 0, ilen = 0;
627
628 if (extra_command_line)
629 xlen = strlen(extra_command_line);
630 if (extra_init_args)
631 ilen = strlen(extra_init_args) + 4; /* for " -- " */
632
633 len = xlen + strlen(boot_command_line) + 1;
634
635 saved_command_line = memblock_alloc(len + ilen, SMP_CACHE_BYTES);
636 if (!saved_command_line)
637 panic("%s: Failed to allocate %zu bytes\n", __func__, len + ilen);
638
639 len = xlen + strlen(command_line) + 1;
640
641 static_command_line = memblock_alloc(len, SMP_CACHE_BYTES);
642 if (!static_command_line)
643 panic("%s: Failed to allocate %zu bytes\n", __func__, len);
644
645 if (xlen) {
646 /*
647 * We have to put extra_command_line before boot command
648 * lines because there could be dashes (separator of init
649 * command line) in the command lines.
650 */
651 strcpy(saved_command_line, extra_command_line);
652 strcpy(static_command_line, extra_command_line);
653 }
654 strcpy(saved_command_line + xlen, boot_command_line);
655 strcpy(static_command_line + xlen, command_line);
656
657 if (ilen) {
658 /*
659 * Append supplemental init boot args to saved_command_line
660 * so that user can check what command line options passed
661 * to init.
662 * The order should always be
663 * " -- "[bootconfig init-param][cmdline init-param]
664 */
665 if (initargs_offs) {
666 len = xlen + initargs_offs;
667 strcpy(saved_command_line + len, extra_init_args);
668 len += ilen - 4; /* strlen(extra_init_args) */
669 strcpy(saved_command_line + len,
670 boot_command_line + initargs_offs - 1);
671 } else {
672 len = strlen(saved_command_line);
673 strcpy(saved_command_line + len, " -- ");
674 len += 4;
675 strcpy(saved_command_line + len, extra_init_args);
676 }
677 }
678
679 saved_command_line_len = strlen(saved_command_line);
680 }
681
682 /*
683 * We need to finalize in a non-__init function or else race conditions
684 * between the root thread and the init thread may cause start_kernel to
685 * be reaped by free_initmem before the root thread has proceeded to
686 * cpu_idle.
687 *
688 * gcc-3.4 accidentally inlines this function, so use noinline.
689 */
690
691 static __initdata DECLARE_COMPLETION(kthreadd_done);
692
rest_init(void)693 static noinline void __ref __noreturn rest_init(void)
694 {
695 struct task_struct *tsk;
696 int pid;
697
698 rcu_scheduler_starting();
699 /*
700 * We need to spawn init first so that it obtains pid 1, however
701 * the init task will end up wanting to create kthreads, which, if
702 * we schedule it before we create kthreadd, will OOPS.
703 */
704 pid = user_mode_thread(kernel_init, NULL, CLONE_FS);
705 /*
706 * Pin init on the boot CPU. Task migration is not properly working
707 * until sched_init_smp() has been run. It will set the allowed
708 * CPUs for init to the non isolated CPUs.
709 */
710 rcu_read_lock();
711 tsk = find_task_by_pid_ns(pid, &init_pid_ns);
712 tsk->flags |= PF_NO_SETAFFINITY;
713 set_cpus_allowed_ptr(tsk, cpumask_of(smp_processor_id()));
714 rcu_read_unlock();
715
716 numa_default_policy();
717 pid = kernel_thread(kthreadd, NULL, NULL, CLONE_FS | CLONE_FILES);
718 rcu_read_lock();
719 kthreadd_task = find_task_by_pid_ns(pid, &init_pid_ns);
720 rcu_read_unlock();
721
722 /*
723 * Enable might_sleep() and smp_processor_id() checks.
724 * They cannot be enabled earlier because with CONFIG_PREEMPTION=y
725 * kernel_thread() would trigger might_sleep() splats. With
726 * CONFIG_PREEMPT_VOLUNTARY=y the init task might have scheduled
727 * already, but it's stuck on the kthreadd_done completion.
728 */
729 system_state = SYSTEM_SCHEDULING;
730
731 complete(&kthreadd_done);
732
733 /*
734 * The boot idle thread must execute schedule()
735 * at least once to get things moving:
736 */
737 schedule_preempt_disabled();
738 /* Call into cpu_idle with preempt disabled */
739 cpu_startup_entry(CPUHP_ONLINE);
740 }
741
742 /* Check for early params. */
do_early_param(char * param,char * val,const char * unused,void * arg)743 static int __init do_early_param(char *param, char *val,
744 const char *unused, void *arg)
745 {
746 const struct obs_kernel_param *p;
747
748 for (p = __setup_start; p < __setup_end; p++) {
749 if ((p->early && parameq(param, p->str)) ||
750 (strcmp(param, "console") == 0 &&
751 strcmp(p->str, "earlycon") == 0)
752 ) {
753 if (p->setup_func(val) != 0)
754 pr_warn("Malformed early option '%s'\n", param);
755 }
756 }
757 /* We accept everything at this stage. */
758 return 0;
759 }
760
parse_early_options(char * cmdline)761 void __init parse_early_options(char *cmdline)
762 {
763 parse_args("early options", cmdline, NULL, 0, 0, 0, NULL,
764 do_early_param);
765 }
766
767 /* Arch code calls this early on, or if not, just before other parsing. */
parse_early_param(void)768 void __init parse_early_param(void)
769 {
770 static int done __initdata;
771 static char tmp_cmdline[COMMAND_LINE_SIZE] __initdata;
772
773 if (done)
774 return;
775
776 /* All fall through to do_early_param. */
777 strscpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);
778 parse_early_options(tmp_cmdline);
779 done = 1;
780 }
781
arch_post_acpi_subsys_init(void)782 void __init __weak arch_post_acpi_subsys_init(void) { }
783
smp_setup_processor_id(void)784 void __init __weak smp_setup_processor_id(void)
785 {
786 }
787
smp_prepare_boot_cpu(void)788 void __init __weak smp_prepare_boot_cpu(void)
789 {
790 }
791
792 # if THREAD_SIZE >= PAGE_SIZE
thread_stack_cache_init(void)793 void __init __weak thread_stack_cache_init(void)
794 {
795 }
796 #endif
797
poking_init(void)798 void __init __weak poking_init(void) { }
799
pgtable_cache_init(void)800 void __init __weak pgtable_cache_init(void) { }
801
trap_init(void)802 void __init __weak trap_init(void) { }
803
804 bool initcall_debug;
805 core_param(initcall_debug, initcall_debug, bool, 0644);
806
807 #ifdef TRACEPOINTS_ENABLED
808 static void __init initcall_debug_enable(void);
809 #else
initcall_debug_enable(void)810 static inline void initcall_debug_enable(void)
811 {
812 }
813 #endif
814
815 #ifdef CONFIG_RANDOMIZE_KSTACK_OFFSET
816 DEFINE_STATIC_KEY_MAYBE_RO(CONFIG_RANDOMIZE_KSTACK_OFFSET_DEFAULT,
817 randomize_kstack_offset);
818 DEFINE_PER_CPU(u32, kstack_offset);
819
early_randomize_kstack_offset(char * buf)820 static int __init early_randomize_kstack_offset(char *buf)
821 {
822 int ret;
823 bool bool_result;
824
825 ret = kstrtobool(buf, &bool_result);
826 if (ret)
827 return ret;
828
829 if (bool_result)
830 static_branch_enable(&randomize_kstack_offset);
831 else
832 static_branch_disable(&randomize_kstack_offset);
833 return 0;
834 }
835 early_param("randomize_kstack_offset", early_randomize_kstack_offset);
836 #endif
837
print_unknown_bootoptions(void)838 static void __init print_unknown_bootoptions(void)
839 {
840 char *unknown_options;
841 char *end;
842 const char *const *p;
843 size_t len;
844
845 if (panic_later || (!argv_init[1] && !envp_init[2]))
846 return;
847
848 /*
849 * Determine how many options we have to print out, plus a space
850 * before each
851 */
852 len = 1; /* null terminator */
853 for (p = &argv_init[1]; *p; p++) {
854 len++;
855 len += strlen(*p);
856 }
857 for (p = &envp_init[2]; *p; p++) {
858 len++;
859 len += strlen(*p);
860 }
861
862 unknown_options = memblock_alloc(len, SMP_CACHE_BYTES);
863 if (!unknown_options) {
864 pr_err("%s: Failed to allocate %zu bytes\n",
865 __func__, len);
866 return;
867 }
868 end = unknown_options;
869
870 for (p = &argv_init[1]; *p; p++)
871 end += sprintf(end, " %s", *p);
872 for (p = &envp_init[2]; *p; p++)
873 end += sprintf(end, " %s", *p);
874
875 /* Start at unknown_options[1] to skip the initial space */
876 pr_notice("Unknown kernel command line parameters \"%s\", will be passed to user space.\n",
877 &unknown_options[1]);
878 memblock_free(unknown_options, len);
879 }
880
881 asmlinkage __visible __init __no_sanitize_address __noreturn __no_stack_protector
start_kernel(void)882 void start_kernel(void)
883 {
884 char *command_line;
885 char *after_dashes;
886
887 set_task_stack_end_magic(&init_task);
888 smp_setup_processor_id();
889 debug_objects_early_init();
890 init_vmlinux_build_id();
891
892 cgroup_init_early();
893
894 local_irq_disable();
895 early_boot_irqs_disabled = true;
896
897 /*
898 * Interrupts are still disabled. Do necessary setups, then
899 * enable them.
900 */
901 boot_cpu_init();
902 page_address_init();
903 pr_notice("%s", linux_banner);
904 early_security_init();
905 setup_arch(&command_line);
906 setup_boot_config();
907 setup_command_line(command_line);
908 setup_nr_cpu_ids();
909 setup_per_cpu_areas();
910 smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */
911 boot_cpu_hotplug_init();
912
913 pr_notice("Kernel command line: %s\n", saved_command_line);
914 /* parameters may set static keys */
915 jump_label_init();
916 parse_early_param();
917 after_dashes = parse_args("Booting kernel",
918 static_command_line, __start___param,
919 __stop___param - __start___param,
920 -1, -1, NULL, &unknown_bootoption);
921 print_unknown_bootoptions();
922 if (!IS_ERR_OR_NULL(after_dashes))
923 parse_args("Setting init args", after_dashes, NULL, 0, -1, -1,
924 NULL, set_init_arg);
925 if (extra_init_args)
926 parse_args("Setting extra init args", extra_init_args,
927 NULL, 0, -1, -1, NULL, set_init_arg);
928
929 /* Architectural and non-timekeeping rng init, before allocator init */
930 random_init_early(command_line);
931
932 /*
933 * These use large bootmem allocations and must precede
934 * initalization of page allocator
935 */
936 setup_log_buf(0);
937 vfs_caches_init_early();
938 sort_main_extable();
939 trap_init();
940 mm_core_init();
941 poking_init();
942 ftrace_init();
943
944 /* trace_printk can be enabled here */
945 early_trace_init();
946
947 /*
948 * Set up the scheduler prior starting any interrupts (such as the
949 * timer interrupt). Full topology setup happens at smp_init()
950 * time - but meanwhile we still have a functioning scheduler.
951 */
952 sched_init();
953
954 if (WARN(!irqs_disabled(),
955 "Interrupts were enabled *very* early, fixing it\n"))
956 local_irq_disable();
957 radix_tree_init();
958 maple_tree_init();
959
960 /*
961 * Set up housekeeping before setting up workqueues to allow the unbound
962 * workqueue to take non-housekeeping into account.
963 */
964 housekeeping_init();
965
966 /*
967 * Allow workqueue creation and work item queueing/cancelling
968 * early. Work item execution depends on kthreads and starts after
969 * workqueue_init().
970 */
971 workqueue_init_early();
972
973 rcu_init();
974
975 /* Trace events are available after this */
976 trace_init();
977
978 if (initcall_debug)
979 initcall_debug_enable();
980
981 context_tracking_init();
982 /* init some links before init_ISA_irqs() */
983 early_irq_init();
984 init_IRQ();
985 tick_init();
986 rcu_init_nohz();
987 init_timers();
988 srcu_init();
989 hrtimers_init();
990 softirq_init();
991 timekeeping_init();
992 time_init();
993
994 /* This must be after timekeeping is initialized */
995 random_init();
996
997 /* These make use of the fully initialized rng */
998 kfence_init();
999 boot_init_stack_canary();
1000
1001 perf_event_init();
1002 profile_init();
1003 call_function_init();
1004 WARN(!irqs_disabled(), "Interrupts were enabled early\n");
1005
1006 early_boot_irqs_disabled = false;
1007 local_irq_enable();
1008
1009 kmem_cache_init_late();
1010
1011 /*
1012 * HACK ALERT! This is early. We're enabling the console before
1013 * we've done PCI setups etc, and console_init() must be aware of
1014 * this. But we do want output early, in case something goes wrong.
1015 */
1016 console_init();
1017 if (panic_later)
1018 panic("Too many boot %s vars at `%s'", panic_later,
1019 panic_param);
1020
1021 lockdep_init();
1022
1023 /*
1024 * Need to run this when irqs are enabled, because it wants
1025 * to self-test [hard/soft]-irqs on/off lock inversion bugs
1026 * too:
1027 */
1028 locking_selftest();
1029
1030 #ifdef CONFIG_BLK_DEV_INITRD
1031 if (initrd_start && !initrd_below_start_ok &&
1032 page_to_pfn(virt_to_page((void *)initrd_start)) < min_low_pfn) {
1033 pr_crit("initrd overwritten (0x%08lx < 0x%08lx) - disabling it.\n",
1034 page_to_pfn(virt_to_page((void *)initrd_start)),
1035 min_low_pfn);
1036 initrd_start = 0;
1037 }
1038 #endif
1039 setup_per_cpu_pageset();
1040 numa_policy_init();
1041 acpi_early_init();
1042 if (late_time_init)
1043 late_time_init();
1044 sched_clock_init();
1045 calibrate_delay();
1046
1047 arch_cpu_finalize_init();
1048
1049 pid_idr_init();
1050 anon_vma_init();
1051 #ifdef CONFIG_X86
1052 if (efi_enabled(EFI_RUNTIME_SERVICES))
1053 efi_enter_virtual_mode();
1054 #endif
1055 thread_stack_cache_init();
1056 cred_init();
1057 fork_init();
1058 proc_caches_init();
1059 uts_ns_init();
1060 key_init();
1061 security_init();
1062 dbg_late_init();
1063 net_ns_init();
1064 vfs_caches_init();
1065 pagecache_init();
1066 signals_init();
1067 seq_file_init();
1068 proc_root_init();
1069 nsfs_init();
1070 pidfs_init();
1071 cpuset_init();
1072 cgroup_init();
1073 taskstats_init_early();
1074 delayacct_init();
1075
1076 acpi_subsystem_init();
1077 arch_post_acpi_subsys_init();
1078 kcsan_init();
1079
1080 /* Do the rest non-__init'ed, we're now alive */
1081 rest_init();
1082
1083 /*
1084 * Avoid stack canaries in callers of boot_init_stack_canary for gcc-10
1085 * and older.
1086 */
1087 #if !__has_attribute(__no_stack_protector__)
1088 prevent_tail_call_optimization();
1089 #endif
1090 }
1091
1092 /* Call all constructor functions linked into the kernel. */
do_ctors(void)1093 static void __init do_ctors(void)
1094 {
1095 /*
1096 * For UML, the constructors have already been called by the
1097 * normal setup code as it's just a normal ELF binary, so we
1098 * cannot do it again - but we do need CONFIG_CONSTRUCTORS
1099 * even on UML for modules.
1100 */
1101 #if defined(CONFIG_CONSTRUCTORS) && !defined(CONFIG_UML)
1102 ctor_fn_t *fn = (ctor_fn_t *) __ctors_start;
1103
1104 for (; fn < (ctor_fn_t *) __ctors_end; fn++)
1105 (*fn)();
1106 #endif
1107 }
1108
1109 #ifdef CONFIG_KALLSYMS
1110 struct blacklist_entry {
1111 struct list_head next;
1112 char *buf;
1113 };
1114
1115 static __initdata_or_module LIST_HEAD(blacklisted_initcalls);
1116
initcall_blacklist(char * str)1117 static int __init initcall_blacklist(char *str)
1118 {
1119 char *str_entry;
1120 struct blacklist_entry *entry;
1121
1122 /* str argument is a comma-separated list of functions */
1123 do {
1124 str_entry = strsep(&str, ",");
1125 if (str_entry) {
1126 pr_debug("blacklisting initcall %s\n", str_entry);
1127 entry = memblock_alloc(sizeof(*entry),
1128 SMP_CACHE_BYTES);
1129 if (!entry)
1130 panic("%s: Failed to allocate %zu bytes\n",
1131 __func__, sizeof(*entry));
1132 entry->buf = memblock_alloc(strlen(str_entry) + 1,
1133 SMP_CACHE_BYTES);
1134 if (!entry->buf)
1135 panic("%s: Failed to allocate %zu bytes\n",
1136 __func__, strlen(str_entry) + 1);
1137 strcpy(entry->buf, str_entry);
1138 list_add(&entry->next, &blacklisted_initcalls);
1139 }
1140 } while (str_entry);
1141
1142 return 1;
1143 }
1144
initcall_blacklisted(initcall_t fn)1145 static bool __init_or_module initcall_blacklisted(initcall_t fn)
1146 {
1147 struct blacklist_entry *entry;
1148 char fn_name[KSYM_SYMBOL_LEN];
1149 unsigned long addr;
1150
1151 if (list_empty(&blacklisted_initcalls))
1152 return false;
1153
1154 addr = (unsigned long) dereference_function_descriptor(fn);
1155 sprint_symbol_no_offset(fn_name, addr);
1156
1157 /*
1158 * fn will be "function_name [module_name]" where [module_name] is not
1159 * displayed for built-in init functions. Strip off the [module_name].
1160 */
1161 strreplace(fn_name, ' ', '\0');
1162
1163 list_for_each_entry(entry, &blacklisted_initcalls, next) {
1164 if (!strcmp(fn_name, entry->buf)) {
1165 pr_debug("initcall %s blacklisted\n", fn_name);
1166 return true;
1167 }
1168 }
1169
1170 return false;
1171 }
1172 #else
initcall_blacklist(char * str)1173 static int __init initcall_blacklist(char *str)
1174 {
1175 pr_warn("initcall_blacklist requires CONFIG_KALLSYMS\n");
1176 return 0;
1177 }
1178
initcall_blacklisted(initcall_t fn)1179 static bool __init_or_module initcall_blacklisted(initcall_t fn)
1180 {
1181 return false;
1182 }
1183 #endif
1184 __setup("initcall_blacklist=", initcall_blacklist);
1185
1186 static __init_or_module void
trace_initcall_start_cb(void * data,initcall_t fn)1187 trace_initcall_start_cb(void *data, initcall_t fn)
1188 {
1189 ktime_t *calltime = data;
1190
1191 printk(KERN_DEBUG "calling %pS @ %i\n", fn, task_pid_nr(current));
1192 *calltime = ktime_get();
1193 }
1194
1195 static __init_or_module void
trace_initcall_finish_cb(void * data,initcall_t fn,int ret)1196 trace_initcall_finish_cb(void *data, initcall_t fn, int ret)
1197 {
1198 ktime_t rettime, *calltime = data;
1199
1200 rettime = ktime_get();
1201 printk(KERN_DEBUG "initcall %pS returned %d after %lld usecs\n",
1202 fn, ret, (unsigned long long)ktime_us_delta(rettime, *calltime));
1203 }
1204
1205 static ktime_t initcall_calltime;
1206
1207 #ifdef TRACEPOINTS_ENABLED
initcall_debug_enable(void)1208 static void __init initcall_debug_enable(void)
1209 {
1210 int ret;
1211
1212 ret = register_trace_initcall_start(trace_initcall_start_cb,
1213 &initcall_calltime);
1214 ret |= register_trace_initcall_finish(trace_initcall_finish_cb,
1215 &initcall_calltime);
1216 WARN(ret, "Failed to register initcall tracepoints\n");
1217 }
1218 # define do_trace_initcall_start trace_initcall_start
1219 # define do_trace_initcall_finish trace_initcall_finish
1220 #else
do_trace_initcall_start(initcall_t fn)1221 static inline void do_trace_initcall_start(initcall_t fn)
1222 {
1223 if (!initcall_debug)
1224 return;
1225 trace_initcall_start_cb(&initcall_calltime, fn);
1226 }
do_trace_initcall_finish(initcall_t fn,int ret)1227 static inline void do_trace_initcall_finish(initcall_t fn, int ret)
1228 {
1229 if (!initcall_debug)
1230 return;
1231 trace_initcall_finish_cb(&initcall_calltime, fn, ret);
1232 }
1233 #endif /* !TRACEPOINTS_ENABLED */
1234
do_one_initcall(initcall_t fn)1235 int __init_or_module do_one_initcall(initcall_t fn)
1236 {
1237 int count = preempt_count();
1238 char msgbuf[64];
1239 int ret;
1240
1241 if (initcall_blacklisted(fn))
1242 return -EPERM;
1243
1244 do_trace_initcall_start(fn);
1245 ret = fn();
1246 do_trace_initcall_finish(fn, ret);
1247
1248 msgbuf[0] = 0;
1249
1250 if (preempt_count() != count) {
1251 sprintf(msgbuf, "preemption imbalance ");
1252 preempt_count_set(count);
1253 }
1254 if (irqs_disabled()) {
1255 strlcat(msgbuf, "disabled interrupts ", sizeof(msgbuf));
1256 local_irq_enable();
1257 }
1258 WARN(msgbuf[0], "initcall %pS returned with %s\n", fn, msgbuf);
1259
1260 add_latent_entropy();
1261 return ret;
1262 }
1263
1264
1265 static initcall_entry_t *initcall_levels[] __initdata = {
1266 __initcall0_start,
1267 __initcall1_start,
1268 __initcall2_start,
1269 __initcall3_start,
1270 __initcall4_start,
1271 __initcall5_start,
1272 __initcall6_start,
1273 __initcall7_start,
1274 __initcall_end,
1275 };
1276
1277 /* Keep these in sync with initcalls in include/linux/init.h */
1278 static const char *initcall_level_names[] __initdata = {
1279 "pure",
1280 "core",
1281 "postcore",
1282 "arch",
1283 "subsys",
1284 "fs",
1285 "device",
1286 "late",
1287 };
1288
ignore_unknown_bootoption(char * param,char * val,const char * unused,void * arg)1289 static int __init ignore_unknown_bootoption(char *param, char *val,
1290 const char *unused, void *arg)
1291 {
1292 return 0;
1293 }
1294
do_initcall_level(int level,char * command_line)1295 static void __init do_initcall_level(int level, char *command_line)
1296 {
1297 initcall_entry_t *fn;
1298
1299 parse_args(initcall_level_names[level],
1300 command_line, __start___param,
1301 __stop___param - __start___param,
1302 level, level,
1303 NULL, ignore_unknown_bootoption);
1304
1305 trace_initcall_level(initcall_level_names[level]);
1306 for (fn = initcall_levels[level]; fn < initcall_levels[level+1]; fn++)
1307 do_one_initcall(initcall_from_entry(fn));
1308 }
1309
do_initcalls(void)1310 static void __init do_initcalls(void)
1311 {
1312 int level;
1313 size_t len = saved_command_line_len + 1;
1314 char *command_line;
1315
1316 command_line = kzalloc(len, GFP_KERNEL);
1317 if (!command_line)
1318 panic("%s: Failed to allocate %zu bytes\n", __func__, len);
1319
1320 for (level = 0; level < ARRAY_SIZE(initcall_levels) - 1; level++) {
1321 /* Parser modifies command_line, restore it each time */
1322 strcpy(command_line, saved_command_line);
1323 do_initcall_level(level, command_line);
1324 }
1325
1326 kfree(command_line);
1327 }
1328
1329 /*
1330 * Ok, the machine is now initialized. None of the devices
1331 * have been touched yet, but the CPU subsystem is up and
1332 * running, and memory and process management works.
1333 *
1334 * Now we can finally start doing some real work..
1335 */
do_basic_setup(void)1336 static void __init do_basic_setup(void)
1337 {
1338 cpuset_init_smp();
1339 driver_init();
1340 init_irq_proc();
1341 do_ctors();
1342 do_initcalls();
1343 }
1344
do_pre_smp_initcalls(void)1345 static void __init do_pre_smp_initcalls(void)
1346 {
1347 initcall_entry_t *fn;
1348
1349 trace_initcall_level("early");
1350 for (fn = __initcall_start; fn < __initcall0_start; fn++)
1351 do_one_initcall(initcall_from_entry(fn));
1352 }
1353
run_init_process(const char * init_filename)1354 static int run_init_process(const char *init_filename)
1355 {
1356 const char *const *p;
1357
1358 argv_init[0] = init_filename;
1359 pr_info("Run %s as init process\n", init_filename);
1360 pr_debug(" with arguments:\n");
1361 for (p = argv_init; *p; p++)
1362 pr_debug(" %s\n", *p);
1363 pr_debug(" with environment:\n");
1364 for (p = envp_init; *p; p++)
1365 pr_debug(" %s\n", *p);
1366 return kernel_execve(init_filename, argv_init, envp_init);
1367 }
1368
try_to_run_init_process(const char * init_filename)1369 static int try_to_run_init_process(const char *init_filename)
1370 {
1371 int ret;
1372
1373 ret = run_init_process(init_filename);
1374
1375 if (ret && ret != -ENOENT) {
1376 pr_err("Starting init: %s exists but couldn't execute it (error %d)\n",
1377 init_filename, ret);
1378 }
1379
1380 return ret;
1381 }
1382
1383 static noinline void __init kernel_init_freeable(void);
1384
1385 #if defined(CONFIG_STRICT_KERNEL_RWX) || defined(CONFIG_STRICT_MODULE_RWX)
1386 bool rodata_enabled __ro_after_init = true;
1387
1388 #ifndef arch_parse_debug_rodata
arch_parse_debug_rodata(char * str)1389 static inline bool arch_parse_debug_rodata(char *str) { return false; }
1390 #endif
1391
set_debug_rodata(char * str)1392 static int __init set_debug_rodata(char *str)
1393 {
1394 if (arch_parse_debug_rodata(str))
1395 return 0;
1396
1397 if (str && !strcmp(str, "on"))
1398 rodata_enabled = true;
1399 else if (str && !strcmp(str, "off"))
1400 rodata_enabled = false;
1401 else
1402 pr_warn("Invalid option string for rodata: '%s'\n", str);
1403 return 0;
1404 }
1405 early_param("rodata", set_debug_rodata);
1406 #endif
1407
mark_readonly(void)1408 static void mark_readonly(void)
1409 {
1410 if (IS_ENABLED(CONFIG_STRICT_KERNEL_RWX) && rodata_enabled) {
1411 /*
1412 * load_module() results in W+X mappings, which are cleaned
1413 * up with init_free_wq. Let's make sure that queued work is
1414 * flushed so that we don't hit false positives looking for
1415 * insecure pages which are W+X.
1416 */
1417 flush_module_init_free_work();
1418 mark_rodata_ro();
1419 debug_checkwx();
1420 rodata_test();
1421 } else if (IS_ENABLED(CONFIG_STRICT_KERNEL_RWX)) {
1422 pr_info("Kernel memory protection disabled.\n");
1423 } else if (IS_ENABLED(CONFIG_ARCH_HAS_STRICT_KERNEL_RWX)) {
1424 pr_warn("Kernel memory protection not selected by kernel config.\n");
1425 } else {
1426 pr_warn("This architecture does not have kernel memory protection.\n");
1427 }
1428 }
1429
free_initmem(void)1430 void __weak free_initmem(void)
1431 {
1432 free_initmem_default(POISON_FREE_INITMEM);
1433 }
1434
kernel_init(void * unused)1435 static int __ref kernel_init(void *unused)
1436 {
1437 int ret;
1438
1439 /*
1440 * Wait until kthreadd is all set-up.
1441 */
1442 wait_for_completion(&kthreadd_done);
1443
1444 kernel_init_freeable();
1445 /* need to finish all async __init code before freeing the memory */
1446 async_synchronize_full();
1447
1448 system_state = SYSTEM_FREEING_INITMEM;
1449 kprobe_free_init_mem();
1450 ftrace_free_init_mem();
1451 kgdb_free_init_mem();
1452 exit_boot_config();
1453 free_initmem();
1454 mark_readonly();
1455
1456 /*
1457 * Kernel mappings are now finalized - update the userspace page-table
1458 * to finalize PTI.
1459 */
1460 pti_finalize();
1461
1462 system_state = SYSTEM_RUNNING;
1463 numa_default_policy();
1464
1465 rcu_end_inkernel_boot();
1466
1467 do_sysctl_args();
1468
1469 if (ramdisk_execute_command) {
1470 ret = run_init_process(ramdisk_execute_command);
1471 if (!ret)
1472 return 0;
1473 pr_err("Failed to execute %s (error %d)\n",
1474 ramdisk_execute_command, ret);
1475 }
1476
1477 /*
1478 * We try each of these until one succeeds.
1479 *
1480 * The Bourne shell can be used instead of init if we are
1481 * trying to recover a really broken machine.
1482 */
1483 if (execute_command) {
1484 ret = run_init_process(execute_command);
1485 if (!ret)
1486 return 0;
1487 panic("Requested init %s failed (error %d).",
1488 execute_command, ret);
1489 }
1490
1491 if (CONFIG_DEFAULT_INIT[0] != '\0') {
1492 ret = run_init_process(CONFIG_DEFAULT_INIT);
1493 if (ret)
1494 pr_err("Default init %s failed (error %d)\n",
1495 CONFIG_DEFAULT_INIT, ret);
1496 else
1497 return 0;
1498 }
1499
1500 if (!try_to_run_init_process("/sbin/init") ||
1501 !try_to_run_init_process("/etc/init") ||
1502 !try_to_run_init_process("/bin/init") ||
1503 !try_to_run_init_process("/bin/sh"))
1504 return 0;
1505
1506 panic("No working init found. Try passing init= option to kernel. "
1507 "See Linux Documentation/admin-guide/init.rst for guidance.");
1508 }
1509
1510 /* Open /dev/console, for stdin/stdout/stderr, this should never fail */
console_on_rootfs(void)1511 void __init console_on_rootfs(void)
1512 {
1513 struct file *file = filp_open("/dev/console", O_RDWR, 0);
1514
1515 if (IS_ERR(file)) {
1516 pr_err("Warning: unable to open an initial console.\n");
1517 return;
1518 }
1519 init_dup(file);
1520 init_dup(file);
1521 init_dup(file);
1522 fput(file);
1523 }
1524
kernel_init_freeable(void)1525 static noinline void __init kernel_init_freeable(void)
1526 {
1527 /* Now the scheduler is fully set up and can do blocking allocations */
1528 gfp_allowed_mask = __GFP_BITS_MASK;
1529
1530 /*
1531 * init can allocate pages on any node
1532 */
1533 set_mems_allowed(node_states[N_MEMORY]);
1534
1535 cad_pid = get_pid(task_pid(current));
1536
1537 smp_prepare_cpus(setup_max_cpus);
1538
1539 workqueue_init();
1540
1541 init_mm_internals();
1542
1543 rcu_init_tasks_generic();
1544 do_pre_smp_initcalls();
1545 lockup_detector_init();
1546
1547 smp_init();
1548 sched_init_smp();
1549
1550 workqueue_init_topology();
1551 async_init();
1552 padata_init();
1553 page_alloc_init_late();
1554
1555 do_basic_setup();
1556
1557 kunit_run_all_tests();
1558
1559 wait_for_initramfs();
1560 console_on_rootfs();
1561
1562 /*
1563 * check if there is an early userspace init. If yes, let it do all
1564 * the work
1565 */
1566 if (init_eaccess(ramdisk_execute_command) != 0) {
1567 ramdisk_execute_command = NULL;
1568 prepare_namespace();
1569 }
1570
1571 /*
1572 * Ok, we have completed the initial bootup, and
1573 * we're essentially up and running. Get rid of the
1574 * initmem segments and start the user-mode stuff..
1575 *
1576 * rootfs is available now, try loading the public keys
1577 * and default modules
1578 */
1579
1580 integrity_load_keys();
1581 }
1582