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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
106static int kernel_init(void *);
107
108extern void init_IRQ(void);
109extern 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 */
118bool early_boot_irqs_disabled __read_mostly;
119
120enum system_states system_state __read_mostly;
121EXPORT_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
129extern void time_init(void);
130/* Default late time init is NULL. archs can override this later. */
131void (*__initdata late_time_init)(void);
132
133/* Untouched command line saved by arch-specific code. */
134char __initdata boot_command_line[COMMAND_LINE_SIZE];
135/* Untouched saved command line (eg. for /proc) */
136char *saved_command_line;
137/* Command line for parameter parsing */
138static char *static_command_line;
139/* Command line for per-initcall parameter parsing */
140static char *initcall_command_line;
141
142static char *execute_command;
143static 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 */
149bool static_key_initialized __read_mostly;
150EXPORT_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 */
161unsigned int reset_devices;
162EXPORT_SYMBOL(reset_devices);
163
164static 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
172static const char *argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
173const char *envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, };
174static const char *panic_later, *panic_param;
175
176extern const struct obs_kernel_param __setup_start[], __setup_end[];
177
178static 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 */
211unsigned long loops_per_jiffy = (1<<12);
212EXPORT_SYMBOL(loops_per_jiffy);
213
214static int __init debug_kernel(char *str)
215{
216 console_loglevel = CONSOLE_LOGLEVEL_DEBUG;
217 return 0;
218}
219
220static int __init quiet_kernel(char *str)
221{
222 console_loglevel = CONSOLE_LOGLEVEL_QUIET;
223 return 0;
224}
225
226early_param("debug", debug_kernel);
227early_param("quiet", quiet_kernel);
228
229static 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
246early_param("loglevel", loglevel);
247
248/* Change NUL term back to "=", to make "param" the whole string. */
249static 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. */
267static 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 */
292static 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
334static 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
351static 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
364static const unsigned int setup_max_cpus = NR_CPUS;
365static inline void setup_nr_cpu_ids(void) { }
366static 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 */
375static 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
404static __initdata DECLARE_COMPLETION(kthreadd_done);
405
406noinline 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. */
455static 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
473void __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. */
480void __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
494void __init __weak arch_post_acpi_subsys_init(void) { }
495
496void __init __weak smp_setup_processor_id(void)
497{
498}
499
500# if THREAD_SIZE >= PAGE_SIZE
501void __init __weak thread_stack_cache_init(void)
502{
503}
504#endif
505
506void __init __weak mem_encrypt_init(void) { }
507
508void __init __weak poking_init(void) { }
509
510void __init __weak pgtable_cache_init(void) { }
511
512bool initcall_debug;
513core_param(initcall_debug, initcall_debug, bool, 0644);
514
515#ifdef TRACEPOINTS_ENABLED
516static void __init initcall_debug_enable(void);
517#else
518static inline void initcall_debug_enable(void)
519{
520}
521#endif
522
523/* Report memory auto-initialization states for this boot. */
524static 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 */
549static 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 report_meminit();
557 mem_init();
558 kmem_cache_init();
559 kmemleak_init();
560 pgtable_init();
561 debug_objects_mem_init();
562 vmalloc_init();
563 ioremap_huge_init();
564 /* Should be run before the first non-init thread is created */
565 init_espfix_bsp();
566 /* Should be run after espfix64 is set up. */
567 pti_init();
568}
569
570void __init __weak arch_call_rest_init(void)
571{
572 rest_init();
573}
574
575asmlinkage __visible void __init start_kernel(void)
576{
577 char *command_line;
578 char *after_dashes;
579
580 set_task_stack_end_magic(&init_task);
581 smp_setup_processor_id();
582 debug_objects_early_init();
583
584 cgroup_init_early();
585
586 local_irq_disable();
587 early_boot_irqs_disabled = true;
588
589 /*
590 * Interrupts are still disabled. Do necessary setups, then
591 * enable them.
592 */
593 boot_cpu_init();
594 page_address_init();
595 pr_notice("%s", linux_banner);
596 early_security_init();
597 setup_arch(&command_line);
598 setup_command_line(command_line);
599 setup_nr_cpu_ids();
600 setup_per_cpu_areas();
601 smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */
602 boot_cpu_hotplug_init();
603
604 build_all_zonelists(NULL);
605 page_alloc_init();
606
607 pr_notice("Kernel command line: %s\n", boot_command_line);
608 /* parameters may set static keys */
609 jump_label_init();
610 parse_early_param();
611 after_dashes = parse_args("Booting kernel",
612 static_command_line, __start___param,
613 __stop___param - __start___param,
614 -1, -1, NULL, &unknown_bootoption);
615 if (!IS_ERR_OR_NULL(after_dashes))
616 parse_args("Setting init args", after_dashes, NULL, 0, -1, -1,
617 NULL, set_init_arg);
618
619 /*
620 * These use large bootmem allocations and must precede
621 * kmem_cache_init()
622 */
623 setup_log_buf(0);
624 vfs_caches_init_early();
625 sort_main_extable();
626 trap_init();
627 mm_init();
628
629 ftrace_init();
630
631 /* trace_printk can be enabled here */
632 early_trace_init();
633
634 /*
635 * Set up the scheduler prior starting any interrupts (such as the
636 * timer interrupt). Full topology setup happens at smp_init()
637 * time - but meanwhile we still have a functioning scheduler.
638 */
639 sched_init();
640 /*
641 * Disable preemption - early bootup scheduling is extremely
642 * fragile until we cpu_idle() for the first time.
643 */
644 preempt_disable();
645 if (WARN(!irqs_disabled(),
646 "Interrupts were enabled *very* early, fixing it\n"))
647 local_irq_disable();
648 radix_tree_init();
649
650 /*
651 * Set up housekeeping before setting up workqueues to allow the unbound
652 * workqueue to take non-housekeeping into account.
653 */
654 housekeeping_init();
655
656 /*
657 * Allow workqueue creation and work item queueing/cancelling
658 * early. Work item execution depends on kthreads and starts after
659 * workqueue_init().
660 */
661 workqueue_init_early();
662
663 rcu_init();
664
665 /* Trace events are available after this */
666 trace_init();
667
668 if (initcall_debug)
669 initcall_debug_enable();
670
671 context_tracking_init();
672 /* init some links before init_ISA_irqs() */
673 early_irq_init();
674 init_IRQ();
675 tick_init();
676 rcu_init_nohz();
677 init_timers();
678 hrtimers_init();
679 softirq_init();
680 timekeeping_init();
681
682 /*
683 * For best initial stack canary entropy, prepare it after:
684 * - setup_arch() for any UEFI RNG entropy and boot cmdline access
685 * - timekeeping_init() for ktime entropy used in rand_initialize()
686 * - rand_initialize() to get any arch-specific entropy like RDRAND
687 * - add_latent_entropy() to get any latent entropy
688 * - adding command line entropy
689 */
690 rand_initialize();
691 add_latent_entropy();
692 add_device_randomness(command_line, strlen(command_line));
693 boot_init_stack_canary();
694
695 time_init();
696 printk_safe_init();
697 perf_event_init();
698 profile_init();
699 call_function_init();
700 WARN(!irqs_disabled(), "Interrupts were enabled early\n");
701
702 early_boot_irqs_disabled = false;
703 local_irq_enable();
704
705 kmem_cache_init_late();
706
707 /*
708 * HACK ALERT! This is early. We're enabling the console before
709 * we've done PCI setups etc, and console_init() must be aware of
710 * this. But we do want output early, in case something goes wrong.
711 */
712 console_init();
713 if (panic_later)
714 panic("Too many boot %s vars at `%s'", panic_later,
715 panic_param);
716
717 lockdep_init();
718
719 /*
720 * Need to run this when irqs are enabled, because it wants
721 * to self-test [hard/soft]-irqs on/off lock inversion bugs
722 * too:
723 */
724 locking_selftest();
725
726 /*
727 * This needs to be called before any devices perform DMA
728 * operations that might use the SWIOTLB bounce buffers. It will
729 * mark the bounce buffers as decrypted so that their usage will
730 * not cause "plain-text" data to be decrypted when accessed.
731 */
732 mem_encrypt_init();
733
734#ifdef CONFIG_BLK_DEV_INITRD
735 if (initrd_start && !initrd_below_start_ok &&
736 page_to_pfn(virt_to_page((void *)initrd_start)) < min_low_pfn) {
737 pr_crit("initrd overwritten (0x%08lx < 0x%08lx) - disabling it.\n",
738 page_to_pfn(virt_to_page((void *)initrd_start)),
739 min_low_pfn);
740 initrd_start = 0;
741 }
742#endif
743 setup_per_cpu_pageset();
744 numa_policy_init();
745 acpi_early_init();
746 if (late_time_init)
747 late_time_init();
748 sched_clock_init();
749 calibrate_delay();
750 pid_idr_init();
751 anon_vma_init();
752#ifdef CONFIG_X86
753 if (efi_enabled(EFI_RUNTIME_SERVICES))
754 efi_enter_virtual_mode();
755#endif
756 thread_stack_cache_init();
757 cred_init();
758 fork_init();
759 proc_caches_init();
760 uts_ns_init();
761 buffer_init();
762 key_init();
763 security_init();
764 dbg_late_init();
765 vfs_caches_init();
766 pagecache_init();
767 signals_init();
768 seq_file_init();
769 proc_root_init();
770 nsfs_init();
771 cpuset_init();
772 cgroup_init();
773 taskstats_init_early();
774 delayacct_init();
775
776 poking_init();
777 check_bugs();
778
779 acpi_subsystem_init();
780 arch_post_acpi_subsys_init();
781 sfi_init_late();
782
783 /* Do the rest non-__init'ed, we're now alive */
784 arch_call_rest_init();
785}
786
787/* Call all constructor functions linked into the kernel. */
788static void __init do_ctors(void)
789{
790#ifdef CONFIG_CONSTRUCTORS
791 ctor_fn_t *fn = (ctor_fn_t *) __ctors_start;
792
793 for (; fn < (ctor_fn_t *) __ctors_end; fn++)
794 (*fn)();
795#endif
796}
797
798#ifdef CONFIG_KALLSYMS
799struct blacklist_entry {
800 struct list_head next;
801 char *buf;
802};
803
804static __initdata_or_module LIST_HEAD(blacklisted_initcalls);
805
806static int __init initcall_blacklist(char *str)
807{
808 char *str_entry;
809 struct blacklist_entry *entry;
810
811 /* str argument is a comma-separated list of functions */
812 do {
813 str_entry = strsep(&str, ",");
814 if (str_entry) {
815 pr_debug("blacklisting initcall %s\n", str_entry);
816 entry = memblock_alloc(sizeof(*entry),
817 SMP_CACHE_BYTES);
818 if (!entry)
819 panic("%s: Failed to allocate %zu bytes\n",
820 __func__, sizeof(*entry));
821 entry->buf = memblock_alloc(strlen(str_entry) + 1,
822 SMP_CACHE_BYTES);
823 if (!entry->buf)
824 panic("%s: Failed to allocate %zu bytes\n",
825 __func__, strlen(str_entry) + 1);
826 strcpy(entry->buf, str_entry);
827 list_add(&entry->next, &blacklisted_initcalls);
828 }
829 } while (str_entry);
830
831 return 0;
832}
833
834static bool __init_or_module initcall_blacklisted(initcall_t fn)
835{
836 struct blacklist_entry *entry;
837 char fn_name[KSYM_SYMBOL_LEN];
838 unsigned long addr;
839
840 if (list_empty(&blacklisted_initcalls))
841 return false;
842
843 addr = (unsigned long) dereference_function_descriptor(fn);
844 sprint_symbol_no_offset(fn_name, addr);
845
846 /*
847 * fn will be "function_name [module_name]" where [module_name] is not
848 * displayed for built-in init functions. Strip off the [module_name].
849 */
850 strreplace(fn_name, ' ', '\0');
851
852 list_for_each_entry(entry, &blacklisted_initcalls, next) {
853 if (!strcmp(fn_name, entry->buf)) {
854 pr_debug("initcall %s blacklisted\n", fn_name);
855 return true;
856 }
857 }
858
859 return false;
860}
861#else
862static int __init initcall_blacklist(char *str)
863{
864 pr_warn("initcall_blacklist requires CONFIG_KALLSYMS\n");
865 return 0;
866}
867
868static bool __init_or_module initcall_blacklisted(initcall_t fn)
869{
870 return false;
871}
872#endif
873__setup("initcall_blacklist=", initcall_blacklist);
874
875static __init_or_module void
876trace_initcall_start_cb(void *data, initcall_t fn)
877{
878 ktime_t *calltime = (ktime_t *)data;
879
880 printk(KERN_DEBUG "calling %pS @ %i\n", fn, task_pid_nr(current));
881 *calltime = ktime_get();
882}
883
884static __init_or_module void
885trace_initcall_finish_cb(void *data, initcall_t fn, int ret)
886{
887 ktime_t *calltime = (ktime_t *)data;
888 ktime_t delta, rettime;
889 unsigned long long duration;
890
891 rettime = ktime_get();
892 delta = ktime_sub(rettime, *calltime);
893 duration = (unsigned long long) ktime_to_ns(delta) >> 10;
894 printk(KERN_DEBUG "initcall %pS returned %d after %lld usecs\n",
895 fn, ret, duration);
896}
897
898static ktime_t initcall_calltime;
899
900#ifdef TRACEPOINTS_ENABLED
901static void __init initcall_debug_enable(void)
902{
903 int ret;
904
905 ret = register_trace_initcall_start(trace_initcall_start_cb,
906 &initcall_calltime);
907 ret |= register_trace_initcall_finish(trace_initcall_finish_cb,
908 &initcall_calltime);
909 WARN(ret, "Failed to register initcall tracepoints\n");
910}
911# define do_trace_initcall_start trace_initcall_start
912# define do_trace_initcall_finish trace_initcall_finish
913#else
914static inline void do_trace_initcall_start(initcall_t fn)
915{
916 if (!initcall_debug)
917 return;
918 trace_initcall_start_cb(&initcall_calltime, fn);
919}
920static inline void do_trace_initcall_finish(initcall_t fn, int ret)
921{
922 if (!initcall_debug)
923 return;
924 trace_initcall_finish_cb(&initcall_calltime, fn, ret);
925}
926#endif /* !TRACEPOINTS_ENABLED */
927
928int __init_or_module do_one_initcall(initcall_t fn)
929{
930 int count = preempt_count();
931 char msgbuf[64];
932 int ret;
933
934 if (initcall_blacklisted(fn))
935 return -EPERM;
936
937 do_trace_initcall_start(fn);
938 ret = fn();
939 do_trace_initcall_finish(fn, ret);
940
941 msgbuf[0] = 0;
942
943 if (preempt_count() != count) {
944 sprintf(msgbuf, "preemption imbalance ");
945 preempt_count_set(count);
946 }
947 if (irqs_disabled()) {
948 strlcat(msgbuf, "disabled interrupts ", sizeof(msgbuf));
949 local_irq_enable();
950 }
951 WARN(msgbuf[0], "initcall %pS returned with %s\n", fn, msgbuf);
952
953 add_latent_entropy();
954 return ret;
955}
956
957
958extern initcall_entry_t __initcall_start[];
959extern initcall_entry_t __initcall0_start[];
960extern initcall_entry_t __initcall1_start[];
961extern initcall_entry_t __initcall2_start[];
962extern initcall_entry_t __initcall3_start[];
963extern initcall_entry_t __initcall4_start[];
964extern initcall_entry_t __initcall5_start[];
965extern initcall_entry_t __initcall6_start[];
966extern initcall_entry_t __initcall7_start[];
967extern initcall_entry_t __initcall_end[];
968
969static initcall_entry_t *initcall_levels[] __initdata = {
970 __initcall0_start,
971 __initcall1_start,
972 __initcall2_start,
973 __initcall3_start,
974 __initcall4_start,
975 __initcall5_start,
976 __initcall6_start,
977 __initcall7_start,
978 __initcall_end,
979};
980
981/* Keep these in sync with initcalls in include/linux/init.h */
982static const char *initcall_level_names[] __initdata = {
983 "pure",
984 "core",
985 "postcore",
986 "arch",
987 "subsys",
988 "fs",
989 "device",
990 "late",
991};
992
993static void __init do_initcall_level(int level)
994{
995 initcall_entry_t *fn;
996
997 strcpy(initcall_command_line, saved_command_line);
998 parse_args(initcall_level_names[level],
999 initcall_command_line, __start___param,
1000 __stop___param - __start___param,
1001 level, level,
1002 NULL, &repair_env_string);
1003
1004 trace_initcall_level(initcall_level_names[level]);
1005 for (fn = initcall_levels[level]; fn < initcall_levels[level+1]; fn++)
1006 do_one_initcall(initcall_from_entry(fn));
1007}
1008
1009static void __init do_initcalls(void)
1010{
1011 int level;
1012
1013 for (level = 0; level < ARRAY_SIZE(initcall_levels) - 1; level++)
1014 do_initcall_level(level);
1015}
1016
1017/*
1018 * Ok, the machine is now initialized. None of the devices
1019 * have been touched yet, but the CPU subsystem is up and
1020 * running, and memory and process management works.
1021 *
1022 * Now we can finally start doing some real work..
1023 */
1024static void __init do_basic_setup(void)
1025{
1026 cpuset_init_smp();
1027 driver_init();
1028 init_irq_proc();
1029 do_ctors();
1030 usermodehelper_enable();
1031 do_initcalls();
1032}
1033
1034static void __init do_pre_smp_initcalls(void)
1035{
1036 initcall_entry_t *fn;
1037
1038 trace_initcall_level("early");
1039 for (fn = __initcall_start; fn < __initcall0_start; fn++)
1040 do_one_initcall(initcall_from_entry(fn));
1041}
1042
1043static int run_init_process(const char *init_filename)
1044{
1045 argv_init[0] = init_filename;
1046 pr_info("Run %s as init process\n", init_filename);
1047 return do_execve(getname_kernel(init_filename),
1048 (const char __user *const __user *)argv_init,
1049 (const char __user *const __user *)envp_init);
1050}
1051
1052static int try_to_run_init_process(const char *init_filename)
1053{
1054 int ret;
1055
1056 ret = run_init_process(init_filename);
1057
1058 if (ret && ret != -ENOENT) {
1059 pr_err("Starting init: %s exists but couldn't execute it (error %d)\n",
1060 init_filename, ret);
1061 }
1062
1063 return ret;
1064}
1065
1066static noinline void __init kernel_init_freeable(void);
1067
1068#if defined(CONFIG_STRICT_KERNEL_RWX) || defined(CONFIG_STRICT_MODULE_RWX)
1069bool rodata_enabled __ro_after_init = true;
1070static int __init set_debug_rodata(char *str)
1071{
1072 return strtobool(str, &rodata_enabled);
1073}
1074__setup("rodata=", set_debug_rodata);
1075#endif
1076
1077#ifdef CONFIG_STRICT_KERNEL_RWX
1078static void mark_readonly(void)
1079{
1080 if (rodata_enabled) {
1081 /*
1082 * load_module() results in W+X mappings, which are cleaned
1083 * up with call_rcu(). Let's make sure that queued work is
1084 * flushed so that we don't hit false positives looking for
1085 * insecure pages which are W+X.
1086 */
1087 rcu_barrier();
1088 mark_rodata_ro();
1089 rodata_test();
1090 } else
1091 pr_info("Kernel memory protection disabled.\n");
1092}
1093#else
1094static inline void mark_readonly(void)
1095{
1096 pr_warn("This architecture does not have kernel memory protection.\n");
1097}
1098#endif
1099
1100void __weak free_initmem(void)
1101{
1102 free_initmem_default(POISON_FREE_INITMEM);
1103}
1104
1105static int __ref kernel_init(void *unused)
1106{
1107 int ret;
1108
1109 kernel_init_freeable();
1110 /* need to finish all async __init code before freeing the memory */
1111 async_synchronize_full();
1112 ftrace_free_init_mem();
1113 free_initmem();
1114 mark_readonly();
1115
1116 /*
1117 * Kernel mappings are now finalized - update the userspace page-table
1118 * to finalize PTI.
1119 */
1120 pti_finalize();
1121
1122 system_state = SYSTEM_RUNNING;
1123 numa_default_policy();
1124
1125 rcu_end_inkernel_boot();
1126
1127 if (ramdisk_execute_command) {
1128 ret = run_init_process(ramdisk_execute_command);
1129 if (!ret)
1130 return 0;
1131 pr_err("Failed to execute %s (error %d)\n",
1132 ramdisk_execute_command, ret);
1133 }
1134
1135 /*
1136 * We try each of these until one succeeds.
1137 *
1138 * The Bourne shell can be used instead of init if we are
1139 * trying to recover a really broken machine.
1140 */
1141 if (execute_command) {
1142 ret = run_init_process(execute_command);
1143 if (!ret)
1144 return 0;
1145 panic("Requested init %s failed (error %d).",
1146 execute_command, ret);
1147 }
1148 if (!try_to_run_init_process("/sbin/init") ||
1149 !try_to_run_init_process("/etc/init") ||
1150 !try_to_run_init_process("/bin/init") ||
1151 !try_to_run_init_process("/bin/sh"))
1152 return 0;
1153
1154 panic("No working init found. Try passing init= option to kernel. "
1155 "See Linux Documentation/admin-guide/init.rst for guidance.");
1156}
1157
1158static noinline void __init kernel_init_freeable(void)
1159{
1160 /*
1161 * Wait until kthreadd is all set-up.
1162 */
1163 wait_for_completion(&kthreadd_done);
1164
1165 /* Now the scheduler is fully set up and can do blocking allocations */
1166 gfp_allowed_mask = __GFP_BITS_MASK;
1167
1168 /*
1169 * init can allocate pages on any node
1170 */
1171 set_mems_allowed(node_states[N_MEMORY]);
1172
1173 cad_pid = task_pid(current);
1174
1175 smp_prepare_cpus(setup_max_cpus);
1176
1177 workqueue_init();
1178
1179 init_mm_internals();
1180
1181 do_pre_smp_initcalls();
1182 lockup_detector_init();
1183
1184 smp_init();
1185 sched_init_smp();
1186
1187 page_alloc_init_late();
1188 /* Initialize page ext after all struct pages are initialized. */
1189 page_ext_init();
1190
1191 do_basic_setup();
1192
1193 /* Open the /dev/console on the rootfs, this should never fail */
1194 if (ksys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0)
1195 pr_err("Warning: unable to open an initial console.\n");
1196
1197 (void) ksys_dup(0);
1198 (void) ksys_dup(0);
1199 /*
1200 * check if there is an early userspace init. If yes, let it do all
1201 * the work
1202 */
1203
1204 if (!ramdisk_execute_command)
1205 ramdisk_execute_command = "/init";
1206
1207 if (ksys_access((const char __user *)
1208 ramdisk_execute_command, 0) != 0) {
1209 ramdisk_execute_command = NULL;
1210 prepare_namespace();
1211 }
1212
1213 /*
1214 * Ok, we have completed the initial bootup, and
1215 * we're essentially up and running. Get rid of the
1216 * initmem segments and start the user-mode stuff..
1217 *
1218 * rootfs is available now, try loading the public keys
1219 * and default modules
1220 */
1221
1222 integrity_load_keys();
1223}
1/*
2 * linux/init/main.c
3 *
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 *
6 * GK 2/5/95 - Changed to support mounting root fs via NFS
7 * Added initrd & change_root: Werner Almesberger & Hans Lermen, Feb '96
8 * Moan early if gcc is old, avoiding bogus kernels - Paul Gortmaker, May '96
9 * Simplified starting of init: Michael A. Griffith <grif@acm.org>
10 */
11
12#include <linux/types.h>
13#include <linux/module.h>
14#include <linux/proc_fs.h>
15#include <linux/kernel.h>
16#include <linux/syscalls.h>
17#include <linux/stackprotector.h>
18#include <linux/string.h>
19#include <linux/ctype.h>
20#include <linux/delay.h>
21#include <linux/ioport.h>
22#include <linux/init.h>
23#include <linux/initrd.h>
24#include <linux/bootmem.h>
25#include <linux/acpi.h>
26#include <linux/tty.h>
27#include <linux/percpu.h>
28#include <linux/kmod.h>
29#include <linux/vmalloc.h>
30#include <linux/kernel_stat.h>
31#include <linux/start_kernel.h>
32#include <linux/security.h>
33#include <linux/smp.h>
34#include <linux/profile.h>
35#include <linux/rcupdate.h>
36#include <linux/moduleparam.h>
37#include <linux/kallsyms.h>
38#include <linux/writeback.h>
39#include <linux/cpu.h>
40#include <linux/cpuset.h>
41#include <linux/cgroup.h>
42#include <linux/efi.h>
43#include <linux/tick.h>
44#include <linux/interrupt.h>
45#include <linux/taskstats_kern.h>
46#include <linux/delayacct.h>
47#include <linux/unistd.h>
48#include <linux/rmap.h>
49#include <linux/mempolicy.h>
50#include <linux/key.h>
51#include <linux/buffer_head.h>
52#include <linux/page_cgroup.h>
53#include <linux/debug_locks.h>
54#include <linux/debugobjects.h>
55#include <linux/lockdep.h>
56#include <linux/kmemleak.h>
57#include <linux/pid_namespace.h>
58#include <linux/device.h>
59#include <linux/kthread.h>
60#include <linux/sched.h>
61#include <linux/signal.h>
62#include <linux/idr.h>
63#include <linux/kgdb.h>
64#include <linux/ftrace.h>
65#include <linux/async.h>
66#include <linux/kmemcheck.h>
67#include <linux/sfi.h>
68#include <linux/shmem_fs.h>
69#include <linux/slab.h>
70#include <linux/perf_event.h>
71
72#include <asm/io.h>
73#include <asm/bugs.h>
74#include <asm/setup.h>
75#include <asm/sections.h>
76#include <asm/cacheflush.h>
77
78#ifdef CONFIG_X86_LOCAL_APIC
79#include <asm/smp.h>
80#endif
81
82static int kernel_init(void *);
83
84extern void init_IRQ(void);
85extern void fork_init(unsigned long);
86extern void mca_init(void);
87extern void sbus_init(void);
88extern void prio_tree_init(void);
89extern void radix_tree_init(void);
90extern void free_initmem(void);
91#ifndef CONFIG_DEBUG_RODATA
92static inline void mark_rodata_ro(void) { }
93#endif
94
95#ifdef CONFIG_TC
96extern void tc_init(void);
97#endif
98
99/*
100 * Debug helper: via this flag we know that we are in 'early bootup code'
101 * where only the boot processor is running with IRQ disabled. This means
102 * two things - IRQ must not be enabled before the flag is cleared and some
103 * operations which are not allowed with IRQ disabled are allowed while the
104 * flag is set.
105 */
106bool early_boot_irqs_disabled __read_mostly;
107
108enum system_states system_state __read_mostly;
109EXPORT_SYMBOL(system_state);
110
111/*
112 * Boot command-line arguments
113 */
114#define MAX_INIT_ARGS CONFIG_INIT_ENV_ARG_LIMIT
115#define MAX_INIT_ENVS CONFIG_INIT_ENV_ARG_LIMIT
116
117extern void time_init(void);
118/* Default late time init is NULL. archs can override this later. */
119void (*__initdata late_time_init)(void);
120extern void softirq_init(void);
121
122/* Untouched command line saved by arch-specific code. */
123char __initdata boot_command_line[COMMAND_LINE_SIZE];
124/* Untouched saved command line (eg. for /proc) */
125char *saved_command_line;
126/* Command line for parameter parsing */
127static char *static_command_line;
128
129static char *execute_command;
130static char *ramdisk_execute_command;
131
132/*
133 * If set, this is an indication to the drivers that reset the underlying
134 * device before going ahead with the initialization otherwise driver might
135 * rely on the BIOS and skip the reset operation.
136 *
137 * This is useful if kernel is booting in an unreliable environment.
138 * For ex. kdump situaiton where previous kernel has crashed, BIOS has been
139 * skipped and devices will be in unknown state.
140 */
141unsigned int reset_devices;
142EXPORT_SYMBOL(reset_devices);
143
144static int __init set_reset_devices(char *str)
145{
146 reset_devices = 1;
147 return 1;
148}
149
150__setup("reset_devices", set_reset_devices);
151
152static const char * argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
153const char * envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, };
154static const char *panic_later, *panic_param;
155
156extern const struct obs_kernel_param __setup_start[], __setup_end[];
157
158static int __init obsolete_checksetup(char *line)
159{
160 const struct obs_kernel_param *p;
161 int had_early_param = 0;
162
163 p = __setup_start;
164 do {
165 int n = strlen(p->str);
166 if (!strncmp(line, p->str, n)) {
167 if (p->early) {
168 /* Already done in parse_early_param?
169 * (Needs exact match on param part).
170 * Keep iterating, as we can have early
171 * params and __setups of same names 8( */
172 if (line[n] == '\0' || line[n] == '=')
173 had_early_param = 1;
174 } else if (!p->setup_func) {
175 printk(KERN_WARNING "Parameter %s is obsolete,"
176 " ignored\n", p->str);
177 return 1;
178 } else if (p->setup_func(line + n))
179 return 1;
180 }
181 p++;
182 } while (p < __setup_end);
183
184 return had_early_param;
185}
186
187/*
188 * This should be approx 2 Bo*oMips to start (note initial shift), and will
189 * still work even if initially too large, it will just take slightly longer
190 */
191unsigned long loops_per_jiffy = (1<<12);
192
193EXPORT_SYMBOL(loops_per_jiffy);
194
195static int __init debug_kernel(char *str)
196{
197 console_loglevel = 10;
198 return 0;
199}
200
201static int __init quiet_kernel(char *str)
202{
203 console_loglevel = 4;
204 return 0;
205}
206
207early_param("debug", debug_kernel);
208early_param("quiet", quiet_kernel);
209
210static int __init loglevel(char *str)
211{
212 int newlevel;
213
214 /*
215 * Only update loglevel value when a correct setting was passed,
216 * to prevent blind crashes (when loglevel being set to 0) that
217 * are quite hard to debug
218 */
219 if (get_option(&str, &newlevel)) {
220 console_loglevel = newlevel;
221 return 0;
222 }
223
224 return -EINVAL;
225}
226
227early_param("loglevel", loglevel);
228
229/*
230 * Unknown boot options get handed to init, unless they look like
231 * unused parameters (modprobe will find them in /proc/cmdline).
232 */
233static int __init unknown_bootoption(char *param, char *val)
234{
235 /* Change NUL term back to "=", to make "param" the whole string. */
236 if (val) {
237 /* param=val or param="val"? */
238 if (val == param+strlen(param)+1)
239 val[-1] = '=';
240 else if (val == param+strlen(param)+2) {
241 val[-2] = '=';
242 memmove(val-1, val, strlen(val)+1);
243 val--;
244 } else
245 BUG();
246 }
247
248 /* Handle obsolete-style parameters */
249 if (obsolete_checksetup(param))
250 return 0;
251
252 /* Unused module parameter. */
253 if (strchr(param, '.') && (!val || strchr(param, '.') < val))
254 return 0;
255
256 if (panic_later)
257 return 0;
258
259 if (val) {
260 /* Environment option */
261 unsigned int i;
262 for (i = 0; envp_init[i]; i++) {
263 if (i == MAX_INIT_ENVS) {
264 panic_later = "Too many boot env vars at `%s'";
265 panic_param = param;
266 }
267 if (!strncmp(param, envp_init[i], val - param))
268 break;
269 }
270 envp_init[i] = param;
271 } else {
272 /* Command line option */
273 unsigned int i;
274 for (i = 0; argv_init[i]; i++) {
275 if (i == MAX_INIT_ARGS) {
276 panic_later = "Too many boot init vars at `%s'";
277 panic_param = param;
278 }
279 }
280 argv_init[i] = param;
281 }
282 return 0;
283}
284
285#ifdef CONFIG_DEBUG_PAGEALLOC
286int __read_mostly debug_pagealloc_enabled = 0;
287#endif
288
289static int __init init_setup(char *str)
290{
291 unsigned int i;
292
293 execute_command = str;
294 /*
295 * In case LILO is going to boot us with default command line,
296 * it prepends "auto" before the whole cmdline which makes
297 * the shell think it should execute a script with such name.
298 * So we ignore all arguments entered _before_ init=... [MJ]
299 */
300 for (i = 1; i < MAX_INIT_ARGS; i++)
301 argv_init[i] = NULL;
302 return 1;
303}
304__setup("init=", init_setup);
305
306static int __init rdinit_setup(char *str)
307{
308 unsigned int i;
309
310 ramdisk_execute_command = str;
311 /* See "auto" comment in init_setup */
312 for (i = 1; i < MAX_INIT_ARGS; i++)
313 argv_init[i] = NULL;
314 return 1;
315}
316__setup("rdinit=", rdinit_setup);
317
318#ifndef CONFIG_SMP
319static const unsigned int setup_max_cpus = NR_CPUS;
320#ifdef CONFIG_X86_LOCAL_APIC
321static void __init smp_init(void)
322{
323 APIC_init_uniprocessor();
324}
325#else
326#define smp_init() do { } while (0)
327#endif
328
329static inline void setup_nr_cpu_ids(void) { }
330static inline void smp_prepare_cpus(unsigned int maxcpus) { }
331#endif
332
333/*
334 * We need to store the untouched command line for future reference.
335 * We also need to store the touched command line since the parameter
336 * parsing is performed in place, and we should allow a component to
337 * store reference of name/value for future reference.
338 */
339static void __init setup_command_line(char *command_line)
340{
341 saved_command_line = alloc_bootmem(strlen (boot_command_line)+1);
342 static_command_line = alloc_bootmem(strlen (command_line)+1);
343 strcpy (saved_command_line, boot_command_line);
344 strcpy (static_command_line, command_line);
345}
346
347/*
348 * We need to finalize in a non-__init function or else race conditions
349 * between the root thread and the init thread may cause start_kernel to
350 * be reaped by free_initmem before the root thread has proceeded to
351 * cpu_idle.
352 *
353 * gcc-3.4 accidentally inlines this function, so use noinline.
354 */
355
356static __initdata DECLARE_COMPLETION(kthreadd_done);
357
358static noinline void __init_refok rest_init(void)
359{
360 int pid;
361
362 rcu_scheduler_starting();
363 /*
364 * We need to spawn init first so that it obtains pid 1, however
365 * the init task will end up wanting to create kthreads, which, if
366 * we schedule it before we create kthreadd, will OOPS.
367 */
368 kernel_thread(kernel_init, NULL, CLONE_FS | CLONE_SIGHAND);
369 numa_default_policy();
370 pid = kernel_thread(kthreadd, NULL, CLONE_FS | CLONE_FILES);
371 rcu_read_lock();
372 kthreadd_task = find_task_by_pid_ns(pid, &init_pid_ns);
373 rcu_read_unlock();
374 complete(&kthreadd_done);
375
376 /*
377 * The boot idle thread must execute schedule()
378 * at least once to get things moving:
379 */
380 init_idle_bootup_task(current);
381 preempt_enable_no_resched();
382 schedule();
383
384 /* Call into cpu_idle with preempt disabled */
385 preempt_disable();
386 cpu_idle();
387}
388
389/* Check for early params. */
390static int __init do_early_param(char *param, char *val)
391{
392 const struct obs_kernel_param *p;
393
394 for (p = __setup_start; p < __setup_end; p++) {
395 if ((p->early && strcmp(param, p->str) == 0) ||
396 (strcmp(param, "console") == 0 &&
397 strcmp(p->str, "earlycon") == 0)
398 ) {
399 if (p->setup_func(val) != 0)
400 printk(KERN_WARNING
401 "Malformed early option '%s'\n", param);
402 }
403 }
404 /* We accept everything at this stage. */
405 return 0;
406}
407
408void __init parse_early_options(char *cmdline)
409{
410 parse_args("early options", cmdline, NULL, 0, do_early_param);
411}
412
413/* Arch code calls this early on, or if not, just before other parsing. */
414void __init parse_early_param(void)
415{
416 static __initdata int done = 0;
417 static __initdata char tmp_cmdline[COMMAND_LINE_SIZE];
418
419 if (done)
420 return;
421
422 /* All fall through to do_early_param. */
423 strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);
424 parse_early_options(tmp_cmdline);
425 done = 1;
426}
427
428/*
429 * Activate the first processor.
430 */
431
432static void __init boot_cpu_init(void)
433{
434 int cpu = smp_processor_id();
435 /* Mark the boot cpu "present", "online" etc for SMP and UP case */
436 set_cpu_online(cpu, true);
437 set_cpu_active(cpu, true);
438 set_cpu_present(cpu, true);
439 set_cpu_possible(cpu, true);
440}
441
442void __init __weak smp_setup_processor_id(void)
443{
444}
445
446void __init __weak thread_info_cache_init(void)
447{
448}
449
450/*
451 * Set up kernel memory allocators
452 */
453static void __init mm_init(void)
454{
455 /*
456 * page_cgroup requires countinous pages as memmap
457 * and it's bigger than MAX_ORDER unless SPARSEMEM.
458 */
459 page_cgroup_init_flatmem();
460 mem_init();
461 kmem_cache_init();
462 percpu_init_late();
463 pgtable_cache_init();
464 vmalloc_init();
465}
466
467asmlinkage void __init start_kernel(void)
468{
469 char * command_line;
470 extern const struct kernel_param __start___param[], __stop___param[];
471
472 smp_setup_processor_id();
473
474 /*
475 * Need to run as early as possible, to initialize the
476 * lockdep hash:
477 */
478 lockdep_init();
479 debug_objects_early_init();
480
481 /*
482 * Set up the the initial canary ASAP:
483 */
484 boot_init_stack_canary();
485
486 cgroup_init_early();
487
488 local_irq_disable();
489 early_boot_irqs_disabled = true;
490
491/*
492 * Interrupts are still disabled. Do necessary setups, then
493 * enable them
494 */
495 tick_init();
496 boot_cpu_init();
497 page_address_init();
498 printk(KERN_NOTICE "%s", linux_banner);
499 setup_arch(&command_line);
500 mm_init_owner(&init_mm, &init_task);
501 mm_init_cpumask(&init_mm);
502 setup_command_line(command_line);
503 setup_nr_cpu_ids();
504 setup_per_cpu_areas();
505 smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */
506
507 build_all_zonelists(NULL);
508 page_alloc_init();
509
510 printk(KERN_NOTICE "Kernel command line: %s\n", boot_command_line);
511 parse_early_param();
512 parse_args("Booting kernel", static_command_line, __start___param,
513 __stop___param - __start___param,
514 &unknown_bootoption);
515 /*
516 * These use large bootmem allocations and must precede
517 * kmem_cache_init()
518 */
519 setup_log_buf(0);
520 pidhash_init();
521 vfs_caches_init_early();
522 sort_main_extable();
523 trap_init();
524 mm_init();
525
526 /*
527 * Set up the scheduler prior starting any interrupts (such as the
528 * timer interrupt). Full topology setup happens at smp_init()
529 * time - but meanwhile we still have a functioning scheduler.
530 */
531 sched_init();
532 /*
533 * Disable preemption - early bootup scheduling is extremely
534 * fragile until we cpu_idle() for the first time.
535 */
536 preempt_disable();
537 if (!irqs_disabled()) {
538 printk(KERN_WARNING "start_kernel(): bug: interrupts were "
539 "enabled *very* early, fixing it\n");
540 local_irq_disable();
541 }
542 idr_init_cache();
543 perf_event_init();
544 rcu_init();
545 radix_tree_init();
546 /* init some links before init_ISA_irqs() */
547 early_irq_init();
548 init_IRQ();
549 prio_tree_init();
550 init_timers();
551 hrtimers_init();
552 softirq_init();
553 timekeeping_init();
554 time_init();
555 profile_init();
556 call_function_init();
557 if (!irqs_disabled())
558 printk(KERN_CRIT "start_kernel(): bug: interrupts were "
559 "enabled early\n");
560 early_boot_irqs_disabled = false;
561 local_irq_enable();
562
563 /* Interrupts are enabled now so all GFP allocations are safe. */
564 gfp_allowed_mask = __GFP_BITS_MASK;
565
566 kmem_cache_init_late();
567
568 /*
569 * HACK ALERT! This is early. We're enabling the console before
570 * we've done PCI setups etc, and console_init() must be aware of
571 * this. But we do want output early, in case something goes wrong.
572 */
573 console_init();
574 if (panic_later)
575 panic(panic_later, panic_param);
576
577 lockdep_info();
578
579 /*
580 * Need to run this when irqs are enabled, because it wants
581 * to self-test [hard/soft]-irqs on/off lock inversion bugs
582 * too:
583 */
584 locking_selftest();
585
586#ifdef CONFIG_BLK_DEV_INITRD
587 if (initrd_start && !initrd_below_start_ok &&
588 page_to_pfn(virt_to_page((void *)initrd_start)) < min_low_pfn) {
589 printk(KERN_CRIT "initrd overwritten (0x%08lx < 0x%08lx) - "
590 "disabling it.\n",
591 page_to_pfn(virt_to_page((void *)initrd_start)),
592 min_low_pfn);
593 initrd_start = 0;
594 }
595#endif
596 page_cgroup_init();
597 enable_debug_pagealloc();
598 debug_objects_mem_init();
599 kmemleak_init();
600 setup_per_cpu_pageset();
601 numa_policy_init();
602 if (late_time_init)
603 late_time_init();
604 sched_clock_init();
605 calibrate_delay();
606 pidmap_init();
607 anon_vma_init();
608#ifdef CONFIG_X86
609 if (efi_enabled)
610 efi_enter_virtual_mode();
611#endif
612 thread_info_cache_init();
613 cred_init();
614 fork_init(totalram_pages);
615 proc_caches_init();
616 buffer_init();
617 key_init();
618 security_init();
619 dbg_late_init();
620 vfs_caches_init(totalram_pages);
621 signals_init();
622 /* rootfs populating might need page-writeback */
623 page_writeback_init();
624#ifdef CONFIG_PROC_FS
625 proc_root_init();
626#endif
627 cgroup_init();
628 cpuset_init();
629 taskstats_init_early();
630 delayacct_init();
631
632 check_bugs();
633
634 acpi_early_init(); /* before LAPIC and SMP init */
635 sfi_init_late();
636
637 ftrace_init();
638
639 /* Do the rest non-__init'ed, we're now alive */
640 rest_init();
641}
642
643/* Call all constructor functions linked into the kernel. */
644static void __init do_ctors(void)
645{
646#ifdef CONFIG_CONSTRUCTORS
647 ctor_fn_t *fn = (ctor_fn_t *) __ctors_start;
648
649 for (; fn < (ctor_fn_t *) __ctors_end; fn++)
650 (*fn)();
651#endif
652}
653
654int initcall_debug;
655core_param(initcall_debug, initcall_debug, bool, 0644);
656
657static char msgbuf[64];
658
659static int __init_or_module do_one_initcall_debug(initcall_t fn)
660{
661 ktime_t calltime, delta, rettime;
662 unsigned long long duration;
663 int ret;
664
665 printk(KERN_DEBUG "calling %pF @ %i\n", fn, task_pid_nr(current));
666 calltime = ktime_get();
667 ret = fn();
668 rettime = ktime_get();
669 delta = ktime_sub(rettime, calltime);
670 duration = (unsigned long long) ktime_to_ns(delta) >> 10;
671 printk(KERN_DEBUG "initcall %pF returned %d after %lld usecs\n", fn,
672 ret, duration);
673
674 return ret;
675}
676
677int __init_or_module do_one_initcall(initcall_t fn)
678{
679 int count = preempt_count();
680 int ret;
681
682 if (initcall_debug)
683 ret = do_one_initcall_debug(fn);
684 else
685 ret = fn();
686
687 msgbuf[0] = 0;
688
689 if (ret && ret != -ENODEV && initcall_debug)
690 sprintf(msgbuf, "error code %d ", ret);
691
692 if (preempt_count() != count) {
693 strlcat(msgbuf, "preemption imbalance ", sizeof(msgbuf));
694 preempt_count() = count;
695 }
696 if (irqs_disabled()) {
697 strlcat(msgbuf, "disabled interrupts ", sizeof(msgbuf));
698 local_irq_enable();
699 }
700 if (msgbuf[0]) {
701 printk("initcall %pF returned with %s\n", fn, msgbuf);
702 }
703
704 return ret;
705}
706
707
708extern initcall_t __initcall_start[], __initcall_end[], __early_initcall_end[];
709
710static void __init do_initcalls(void)
711{
712 initcall_t *fn;
713
714 for (fn = __early_initcall_end; fn < __initcall_end; fn++)
715 do_one_initcall(*fn);
716}
717
718/*
719 * Ok, the machine is now initialized. None of the devices
720 * have been touched yet, but the CPU subsystem is up and
721 * running, and memory and process management works.
722 *
723 * Now we can finally start doing some real work..
724 */
725static void __init do_basic_setup(void)
726{
727 cpuset_init_smp();
728 usermodehelper_init();
729 shmem_init();
730 driver_init();
731 init_irq_proc();
732 do_ctors();
733 usermodehelper_enable();
734 do_initcalls();
735}
736
737static void __init do_pre_smp_initcalls(void)
738{
739 initcall_t *fn;
740
741 for (fn = __initcall_start; fn < __early_initcall_end; fn++)
742 do_one_initcall(*fn);
743}
744
745static void run_init_process(const char *init_filename)
746{
747 argv_init[0] = init_filename;
748 kernel_execve(init_filename, argv_init, envp_init);
749}
750
751/* This is a non __init function. Force it to be noinline otherwise gcc
752 * makes it inline to init() and it becomes part of init.text section
753 */
754static noinline int init_post(void)
755{
756 /* need to finish all async __init code before freeing the memory */
757 async_synchronize_full();
758 free_initmem();
759 mark_rodata_ro();
760 system_state = SYSTEM_RUNNING;
761 numa_default_policy();
762
763
764 current->signal->flags |= SIGNAL_UNKILLABLE;
765
766 if (ramdisk_execute_command) {
767 run_init_process(ramdisk_execute_command);
768 printk(KERN_WARNING "Failed to execute %s\n",
769 ramdisk_execute_command);
770 }
771
772 /*
773 * We try each of these until one succeeds.
774 *
775 * The Bourne shell can be used instead of init if we are
776 * trying to recover a really broken machine.
777 */
778 if (execute_command) {
779 run_init_process(execute_command);
780 printk(KERN_WARNING "Failed to execute %s. Attempting "
781 "defaults...\n", execute_command);
782 }
783 run_init_process("/sbin/init");
784 run_init_process("/etc/init");
785 run_init_process("/bin/init");
786 run_init_process("/bin/sh");
787
788 panic("No init found. Try passing init= option to kernel. "
789 "See Linux Documentation/init.txt for guidance.");
790}
791
792static int __init kernel_init(void * unused)
793{
794 /*
795 * Wait until kthreadd is all set-up.
796 */
797 wait_for_completion(&kthreadd_done);
798 /*
799 * init can allocate pages on any node
800 */
801 set_mems_allowed(node_states[N_HIGH_MEMORY]);
802 /*
803 * init can run on any cpu.
804 */
805 set_cpus_allowed_ptr(current, cpu_all_mask);
806
807 cad_pid = task_pid(current);
808
809 smp_prepare_cpus(setup_max_cpus);
810
811 do_pre_smp_initcalls();
812 lockup_detector_init();
813
814 smp_init();
815 sched_init_smp();
816
817 do_basic_setup();
818
819 /* Open the /dev/console on the rootfs, this should never fail */
820 if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0)
821 printk(KERN_WARNING "Warning: unable to open an initial console.\n");
822
823 (void) sys_dup(0);
824 (void) sys_dup(0);
825 /*
826 * check if there is an early userspace init. If yes, let it do all
827 * the work
828 */
829
830 if (!ramdisk_execute_command)
831 ramdisk_execute_command = "/init";
832
833 if (sys_access((const char __user *) ramdisk_execute_command, 0) != 0) {
834 ramdisk_execute_command = NULL;
835 prepare_namespace();
836 }
837
838 /*
839 * Ok, we have completed the initial bootup, and
840 * we're essentially up and running. Get rid of the
841 * initmem segments and start the user-mode stuff..
842 */
843
844 init_post();
845 return 0;
846}