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