4 * Copyright (C) 1991, 1992 Linus Torvalds
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>
12 #define DEBUG /* Enable initcall_debug */
14 #include <linux/types.h>
15 #include <linux/extable.h>
16 #include <linux/module.h>
17 #include <linux/proc_fs.h>
18 #include <linux/binfmts.h>
19 #include <linux/kernel.h>
20 #include <linux/syscalls.h>
21 #include <linux/stackprotector.h>
22 #include <linux/string.h>
23 #include <linux/ctype.h>
24 #include <linux/delay.h>
25 #include <linux/ioport.h>
26 #include <linux/init.h>
27 #include <linux/initrd.h>
28 #include <linux/bootmem.h>
29 #include <linux/acpi.h>
30 #include <linux/console.h>
31 #include <linux/nmi.h>
32 #include <linux/percpu.h>
33 #include <linux/kmod.h>
34 #include <linux/vmalloc.h>
35 #include <linux/kernel_stat.h>
36 #include <linux/start_kernel.h>
37 #include <linux/security.h>
38 #include <linux/smp.h>
39 #include <linux/profile.h>
40 #include <linux/rcupdate.h>
41 #include <linux/moduleparam.h>
42 #include <linux/kallsyms.h>
43 #include <linux/writeback.h>
44 #include <linux/cpu.h>
45 #include <linux/cpuset.h>
46 #include <linux/cgroup.h>
47 #include <linux/efi.h>
48 #include <linux/tick.h>
49 #include <linux/interrupt.h>
50 #include <linux/taskstats_kern.h>
51 #include <linux/delayacct.h>
52 #include <linux/unistd.h>
53 #include <linux/rmap.h>
54 #include <linux/mempolicy.h>
55 #include <linux/key.h>
56 #include <linux/buffer_head.h>
57 #include <linux/page_ext.h>
58 #include <linux/debug_locks.h>
59 #include <linux/debugobjects.h>
60 #include <linux/lockdep.h>
61 #include <linux/kmemleak.h>
62 #include <linux/pid_namespace.h>
63 #include <linux/device.h>
64 #include <linux/kthread.h>
65 #include <linux/sched.h>
66 #include <linux/sched/init.h>
67 #include <linux/signal.h>
68 #include <linux/idr.h>
69 #include <linux/kgdb.h>
70 #include <linux/ftrace.h>
71 #include <linux/async.h>
72 #include <linux/sfi.h>
73 #include <linux/shmem_fs.h>
74 #include <linux/slab.h>
75 #include <linux/perf_event.h>
76 #include <linux/ptrace.h>
77 #include <linux/pti.h>
78 #include <linux/blkdev.h>
79 #include <linux/elevator.h>
80 #include <linux/sched_clock.h>
81 #include <linux/sched/task.h>
82 #include <linux/sched/task_stack.h>
83 #include <linux/context_tracking.h>
84 #include <linux/random.h>
85 #include <linux/list.h>
86 #include <linux/integrity.h>
87 #include <linux/proc_ns.h>
89 #include <linux/cache.h>
90 #include <linux/rodata_test.h>
94 #include <asm/setup.h>
95 #include <asm/sections.h>
96 #include <asm/cacheflush.h>
98 static int kernel_init(void *);
100 extern void init_IRQ(void);
101 extern void radix_tree_init(void);
104 * Debug helper: via this flag we know that we are in 'early bootup code'
105 * where only the boot processor is running with IRQ disabled. This means
106 * two things - IRQ must not be enabled before the flag is cleared and some
107 * operations which are not allowed with IRQ disabled are allowed while the
110 bool early_boot_irqs_disabled __read_mostly;
112 enum system_states system_state __read_mostly;
113 EXPORT_SYMBOL(system_state);
116 * Boot command-line arguments
118 #define MAX_INIT_ARGS CONFIG_INIT_ENV_ARG_LIMIT
119 #define MAX_INIT_ENVS CONFIG_INIT_ENV_ARG_LIMIT
121 extern void time_init(void);
122 /* Default late time init is NULL. archs can override this later. */
123 void (*__initdata late_time_init)(void);
125 /* Untouched command line saved by arch-specific code. */
126 char __initdata boot_command_line[COMMAND_LINE_SIZE];
127 /* Untouched saved command line (eg. for /proc) */
128 char *saved_command_line;
129 /* Command line for parameter parsing */
130 static char *static_command_line;
131 /* Command line for per-initcall parameter parsing */
132 static char *initcall_command_line;
134 static char *execute_command;
135 static char *ramdisk_execute_command;
138 * Used to generate warnings if static_key manipulation functions are used
139 * before jump_label_init is called.
141 bool static_key_initialized __read_mostly;
142 EXPORT_SYMBOL_GPL(static_key_initialized);
145 * If set, this is an indication to the drivers that reset the underlying
146 * device before going ahead with the initialization otherwise driver might
147 * rely on the BIOS and skip the reset operation.
149 * This is useful if kernel is booting in an unreliable environment.
150 * For ex. kdump situation where previous kernel has crashed, BIOS has been
151 * skipped and devices will be in unknown state.
153 unsigned int reset_devices;
154 EXPORT_SYMBOL(reset_devices);
156 static int __init set_reset_devices(char *str)
162 __setup("reset_devices", set_reset_devices);
164 static const char *argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
165 const char *envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, };
166 static const char *panic_later, *panic_param;
168 extern const struct obs_kernel_param __setup_start[], __setup_end[];
170 static bool __init obsolete_checksetup(char *line)
172 const struct obs_kernel_param *p;
173 bool had_early_param = false;
177 int n = strlen(p->str);
178 if (parameqn(line, p->str, n)) {
180 /* Already done in parse_early_param?
181 * (Needs exact match on param part).
182 * Keep iterating, as we can have early
183 * params and __setups of same names 8( */
184 if (line[n] == '\0' || line[n] == '=')
185 had_early_param = true;
186 } else if (!p->setup_func) {
187 pr_warn("Parameter %s is obsolete, ignored\n",
190 } else if (p->setup_func(line + n))
194 } while (p < __setup_end);
196 return had_early_param;
200 * This should be approx 2 Bo*oMips to start (note initial shift), and will
201 * still work even if initially too large, it will just take slightly longer
203 unsigned long loops_per_jiffy = (1<<12);
204 EXPORT_SYMBOL(loops_per_jiffy);
206 static int __init debug_kernel(char *str)
208 console_loglevel = CONSOLE_LOGLEVEL_DEBUG;
212 static int __init quiet_kernel(char *str)
214 console_loglevel = CONSOLE_LOGLEVEL_QUIET;
218 early_param("debug", debug_kernel);
219 early_param("quiet", quiet_kernel);
221 static int __init loglevel(char *str)
226 * Only update loglevel value when a correct setting was passed,
227 * to prevent blind crashes (when loglevel being set to 0) that
228 * are quite hard to debug
230 if (get_option(&str, &newlevel)) {
231 console_loglevel = newlevel;
238 early_param("loglevel", loglevel);
240 /* Change NUL term back to "=", to make "param" the whole string. */
241 static int __init repair_env_string(char *param, char *val,
242 const char *unused, void *arg)
245 /* param=val or param="val"? */
246 if (val == param+strlen(param)+1)
248 else if (val == param+strlen(param)+2) {
250 memmove(val-1, val, strlen(val)+1);
258 /* Anything after -- gets handed straight to init. */
259 static int __init set_init_arg(char *param, char *val,
260 const char *unused, void *arg)
267 repair_env_string(param, val, unused, NULL);
269 for (i = 0; argv_init[i]; i++) {
270 if (i == MAX_INIT_ARGS) {
271 panic_later = "init";
276 argv_init[i] = param;
281 * Unknown boot options get handed to init, unless they look like
282 * unused parameters (modprobe will find them in /proc/cmdline).
284 static int __init unknown_bootoption(char *param, char *val,
285 const char *unused, void *arg)
287 repair_env_string(param, val, unused, NULL);
289 /* Handle obsolete-style parameters */
290 if (obsolete_checksetup(param))
293 /* Unused module parameter. */
294 if (strchr(param, '.') && (!val || strchr(param, '.') < val))
301 /* Environment option */
303 for (i = 0; envp_init[i]; i++) {
304 if (i == MAX_INIT_ENVS) {
308 if (!strncmp(param, envp_init[i], val - param))
311 envp_init[i] = param;
313 /* Command line option */
315 for (i = 0; argv_init[i]; i++) {
316 if (i == MAX_INIT_ARGS) {
317 panic_later = "init";
321 argv_init[i] = param;
326 static int __init init_setup(char *str)
330 execute_command = str;
332 * In case LILO is going to boot us with default command line,
333 * it prepends "auto" before the whole cmdline which makes
334 * the shell think it should execute a script with such name.
335 * So we ignore all arguments entered _before_ init=... [MJ]
337 for (i = 1; i < MAX_INIT_ARGS; i++)
341 __setup("init=", init_setup);
343 static int __init rdinit_setup(char *str)
347 ramdisk_execute_command = str;
348 /* See "auto" comment in init_setup */
349 for (i = 1; i < MAX_INIT_ARGS; i++)
353 __setup("rdinit=", rdinit_setup);
356 static const unsigned int setup_max_cpus = NR_CPUS;
357 static inline void setup_nr_cpu_ids(void) { }
358 static inline void smp_prepare_cpus(unsigned int maxcpus) { }
362 * We need to store the untouched command line for future reference.
363 * We also need to store the touched command line since the parameter
364 * parsing is performed in place, and we should allow a component to
365 * store reference of name/value for future reference.
367 static void __init setup_command_line(char *command_line)
370 memblock_virt_alloc(strlen(boot_command_line) + 1, 0);
371 initcall_command_line =
372 memblock_virt_alloc(strlen(boot_command_line) + 1, 0);
373 static_command_line = memblock_virt_alloc(strlen(command_line) + 1, 0);
374 strcpy(saved_command_line, boot_command_line);
375 strcpy(static_command_line, command_line);
379 * We need to finalize in a non-__init function or else race conditions
380 * between the root thread and the init thread may cause start_kernel to
381 * be reaped by free_initmem before the root thread has proceeded to
384 * gcc-3.4 accidentally inlines this function, so use noinline.
387 static __initdata DECLARE_COMPLETION(kthreadd_done);
389 static noinline void __ref rest_init(void)
391 struct task_struct *tsk;
394 rcu_scheduler_starting();
396 * We need to spawn init first so that it obtains pid 1, however
397 * the init task will end up wanting to create kthreads, which, if
398 * we schedule it before we create kthreadd, will OOPS.
400 pid = kernel_thread(kernel_init, NULL, CLONE_FS);
402 * Pin init on the boot CPU. Task migration is not properly working
403 * until sched_init_smp() has been run. It will set the allowed
404 * CPUs for init to the non isolated CPUs.
407 tsk = find_task_by_pid_ns(pid, &init_pid_ns);
408 set_cpus_allowed_ptr(tsk, cpumask_of(smp_processor_id()));
411 numa_default_policy();
412 pid = kernel_thread(kthreadd, NULL, CLONE_FS | CLONE_FILES);
414 kthreadd_task = find_task_by_pid_ns(pid, &init_pid_ns);
418 * Enable might_sleep() and smp_processor_id() checks.
419 * They cannot be enabled earlier because with CONFIG_PRREMPT=y
420 * kernel_thread() would trigger might_sleep() splats. With
421 * CONFIG_PREEMPT_VOLUNTARY=y the init task might have scheduled
422 * already, but it's stuck on the kthreadd_done completion.
424 system_state = SYSTEM_SCHEDULING;
426 complete(&kthreadd_done);
429 * The boot idle thread must execute schedule()
430 * at least once to get things moving:
432 schedule_preempt_disabled();
433 /* Call into cpu_idle with preempt disabled */
434 cpu_startup_entry(CPUHP_ONLINE);
437 /* Check for early params. */
438 static int __init do_early_param(char *param, char *val,
439 const char *unused, void *arg)
441 const struct obs_kernel_param *p;
443 for (p = __setup_start; p < __setup_end; p++) {
444 if ((p->early && parameq(param, p->str)) ||
445 (strcmp(param, "console") == 0 &&
446 strcmp(p->str, "earlycon") == 0)
448 if (p->setup_func(val) != 0)
449 pr_warn("Malformed early option '%s'\n", param);
452 /* We accept everything at this stage. */
456 void __init parse_early_options(char *cmdline)
458 parse_args("early options", cmdline, NULL, 0, 0, 0, NULL,
462 /* Arch code calls this early on, or if not, just before other parsing. */
463 void __init parse_early_param(void)
465 static int done __initdata;
466 static char tmp_cmdline[COMMAND_LINE_SIZE] __initdata;
471 /* All fall through to do_early_param. */
472 strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);
473 parse_early_options(tmp_cmdline);
477 void __init __weak arch_post_acpi_subsys_init(void) { }
479 void __init __weak smp_setup_processor_id(void)
483 # if THREAD_SIZE >= PAGE_SIZE
484 void __init __weak thread_stack_cache_init(void)
489 void __init __weak mem_encrypt_init(void) { }
492 * Set up kernel memory allocators
494 static void __init mm_init(void)
497 * page_ext requires contiguous pages,
498 * bigger than MAX_ORDER unless SPARSEMEM.
500 page_ext_init_flatmem();
506 /* Should be run before the first non-init thread is created */
508 /* Should be run after espfix64 is set up. */
512 asmlinkage __visible void __init start_kernel(void)
517 set_task_stack_end_magic(&init_task);
518 smp_setup_processor_id();
519 debug_objects_early_init();
524 early_boot_irqs_disabled = true;
527 * Interrupts are still disabled. Do necessary setups, then
532 pr_notice("%s", linux_banner);
533 setup_arch(&command_line);
534 mm_init_cpumask(&init_mm);
535 setup_command_line(command_line);
537 setup_per_cpu_areas();
538 smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */
539 boot_cpu_hotplug_init();
541 build_all_zonelists(NULL);
544 pr_notice("Kernel command line: %s\n", boot_command_line);
545 /* parameters may set static keys */
548 after_dashes = parse_args("Booting kernel",
549 static_command_line, __start___param,
550 __stop___param - __start___param,
551 -1, -1, NULL, &unknown_bootoption);
552 if (!IS_ERR_OR_NULL(after_dashes))
553 parse_args("Setting init args", after_dashes, NULL, 0, -1, -1,
557 * These use large bootmem allocations and must precede
562 vfs_caches_init_early();
569 /* trace_printk can be enabled here */
573 * Set up the scheduler prior starting any interrupts (such as the
574 * timer interrupt). Full topology setup happens at smp_init()
575 * time - but meanwhile we still have a functioning scheduler.
579 * Disable preemption - early bootup scheduling is extremely
580 * fragile until we cpu_idle() for the first time.
583 if (WARN(!irqs_disabled(),
584 "Interrupts were enabled *very* early, fixing it\n"))
589 * Allow workqueue creation and work item queueing/cancelling
590 * early. Work item execution depends on kthreads and starts after
593 workqueue_init_early();
597 /* Trace events are available after this */
600 context_tracking_init();
601 /* init some links before init_ISA_irqs() */
613 * For best initial stack canary entropy, prepare it after:
614 * - setup_arch() for any UEFI RNG entropy and boot cmdline access
615 * - timekeeping_init() for ktime entropy used in random_init()
616 * - time_init() for making random_get_entropy() work on some platforms
617 * - random_init() to initialize the RNG from from early entropy sources
619 random_init(command_line);
620 boot_init_stack_canary();
622 sched_clock_postinit();
626 call_function_init();
627 WARN(!irqs_disabled(), "Interrupts were enabled early\n");
628 early_boot_irqs_disabled = false;
631 kmem_cache_init_late();
634 * HACK ALERT! This is early. We're enabling the console before
635 * we've done PCI setups etc, and console_init() must be aware of
636 * this. But we do want output early, in case something goes wrong.
640 panic("Too many boot %s vars at `%s'", panic_later,
646 * Need to run this when irqs are enabled, because it wants
647 * to self-test [hard/soft]-irqs on/off lock inversion bugs
653 * This needs to be called before any devices perform DMA
654 * operations that might use the SWIOTLB bounce buffers. It will
655 * mark the bounce buffers as decrypted so that their usage will
656 * not cause "plain-text" data to be decrypted when accessed.
660 #ifdef CONFIG_BLK_DEV_INITRD
661 if (initrd_start && !initrd_below_start_ok &&
662 page_to_pfn(virt_to_page((void *)initrd_start)) < min_low_pfn) {
663 pr_crit("initrd overwritten (0x%08lx < 0x%08lx) - disabling it.\n",
664 page_to_pfn(virt_to_page((void *)initrd_start)),
670 debug_objects_mem_init();
671 setup_per_cpu_pageset();
680 if (efi_enabled(EFI_RUNTIME_SERVICES))
681 efi_enter_virtual_mode();
683 thread_stack_cache_init();
698 taskstats_init_early();
703 acpi_subsystem_init();
704 arch_post_acpi_subsys_init();
707 if (efi_enabled(EFI_RUNTIME_SERVICES)) {
708 efi_free_boot_services();
711 /* Do the rest non-__init'ed, we're now alive */
714 prevent_tail_call_optimization();
717 /* Call all constructor functions linked into the kernel. */
718 static void __init do_ctors(void)
720 #ifdef CONFIG_CONSTRUCTORS
721 ctor_fn_t *fn = (ctor_fn_t *) __ctors_start;
723 for (; fn < (ctor_fn_t *) __ctors_end; fn++)
729 core_param(initcall_debug, initcall_debug, bool, 0644);
731 #ifdef CONFIG_KALLSYMS
732 struct blacklist_entry {
733 struct list_head next;
737 static __initdata_or_module LIST_HEAD(blacklisted_initcalls);
739 static int __init initcall_blacklist(char *str)
742 struct blacklist_entry *entry;
744 /* str argument is a comma-separated list of functions */
746 str_entry = strsep(&str, ",");
748 pr_debug("blacklisting initcall %s\n", str_entry);
749 entry = alloc_bootmem(sizeof(*entry));
750 entry->buf = alloc_bootmem(strlen(str_entry) + 1);
751 strcpy(entry->buf, str_entry);
752 list_add(&entry->next, &blacklisted_initcalls);
759 static bool __init_or_module initcall_blacklisted(initcall_t fn)
761 struct blacklist_entry *entry;
762 char fn_name[KSYM_SYMBOL_LEN];
765 if (list_empty(&blacklisted_initcalls))
768 addr = (unsigned long) dereference_function_descriptor(fn);
769 sprint_symbol_no_offset(fn_name, addr);
772 * fn will be "function_name [module_name]" where [module_name] is not
773 * displayed for built-in init functions. Strip off the [module_name].
775 strreplace(fn_name, ' ', '\0');
777 list_for_each_entry(entry, &blacklisted_initcalls, next) {
778 if (!strcmp(fn_name, entry->buf)) {
779 pr_debug("initcall %s blacklisted\n", fn_name);
787 static int __init initcall_blacklist(char *str)
789 pr_warn("initcall_blacklist requires CONFIG_KALLSYMS\n");
793 static bool __init_or_module initcall_blacklisted(initcall_t fn)
798 __setup("initcall_blacklist=", initcall_blacklist);
800 static int __init_or_module do_one_initcall_debug(initcall_t fn)
802 ktime_t calltime, delta, rettime;
803 unsigned long long duration;
806 printk(KERN_DEBUG "calling %pF @ %i\n", fn, task_pid_nr(current));
807 calltime = ktime_get();
809 rettime = ktime_get();
810 delta = ktime_sub(rettime, calltime);
811 duration = (unsigned long long) ktime_to_ns(delta) >> 10;
812 printk(KERN_DEBUG "initcall %pF returned %d after %lld usecs\n",
818 int __init_or_module do_one_initcall(initcall_t fn)
820 int count = preempt_count();
824 if (initcall_blacklisted(fn))
828 ret = do_one_initcall_debug(fn);
834 if (preempt_count() != count) {
835 sprintf(msgbuf, "preemption imbalance ");
836 preempt_count_set(count);
838 if (irqs_disabled()) {
839 strlcat(msgbuf, "disabled interrupts ", sizeof(msgbuf));
842 WARN(msgbuf[0], "initcall %pF returned with %s\n", fn, msgbuf);
844 add_latent_entropy();
849 extern initcall_t __initcall_start[];
850 extern initcall_t __initcall0_start[];
851 extern initcall_t __initcall1_start[];
852 extern initcall_t __initcall2_start[];
853 extern initcall_t __initcall3_start[];
854 extern initcall_t __initcall4_start[];
855 extern initcall_t __initcall5_start[];
856 extern initcall_t __initcall6_start[];
857 extern initcall_t __initcall7_start[];
858 extern initcall_t __initcall_end[];
860 static initcall_t *initcall_levels[] __initdata = {
872 /* Keep these in sync with initcalls in include/linux/init.h */
873 static char *initcall_level_names[] __initdata = {
884 static void __init do_initcall_level(int level)
888 strcpy(initcall_command_line, saved_command_line);
889 parse_args(initcall_level_names[level],
890 initcall_command_line, __start___param,
891 __stop___param - __start___param,
893 NULL, &repair_env_string);
895 for (fn = initcall_levels[level]; fn < initcall_levels[level+1]; fn++)
896 do_one_initcall(*fn);
899 static void __init do_initcalls(void)
903 for (level = 0; level < ARRAY_SIZE(initcall_levels) - 1; level++)
904 do_initcall_level(level);
908 * Ok, the machine is now initialized. None of the devices
909 * have been touched yet, but the CPU subsystem is up and
910 * running, and memory and process management works.
912 * Now we can finally start doing some real work..
914 static void __init do_basic_setup(void)
921 usermodehelper_enable();
925 static void __init do_pre_smp_initcalls(void)
929 for (fn = __initcall_start; fn < __initcall0_start; fn++)
930 do_one_initcall(*fn);
934 * This function requests modules which should be loaded by default and is
935 * called twice right after initrd is mounted and right before init is
936 * exec'd. If such modules are on either initrd or rootfs, they will be
937 * loaded before control is passed to userland.
939 void __init load_default_modules(void)
941 load_default_elevator_module();
944 static int run_init_process(const char *init_filename)
946 argv_init[0] = init_filename;
947 return do_execve(getname_kernel(init_filename),
948 (const char __user *const __user *)argv_init,
949 (const char __user *const __user *)envp_init);
952 static int try_to_run_init_process(const char *init_filename)
956 ret = run_init_process(init_filename);
958 if (ret && ret != -ENOENT) {
959 pr_err("Starting init: %s exists but couldn't execute it (error %d)\n",
966 static noinline void __init kernel_init_freeable(void);
968 #if defined(CONFIG_STRICT_KERNEL_RWX) || defined(CONFIG_STRICT_MODULE_RWX)
969 bool rodata_enabled __ro_after_init = true;
970 static int __init set_debug_rodata(char *str)
972 if (strtobool(str, &rodata_enabled))
973 pr_warn("Invalid option string for rodata: '%s'\n", str);
976 __setup("rodata=", set_debug_rodata);
979 #ifdef CONFIG_STRICT_KERNEL_RWX
980 static void mark_readonly(void)
982 if (rodata_enabled) {
984 * load_module() results in W+X mappings, which are cleaned up
985 * with call_rcu_sched(). Let's make sure that queued work is
986 * flushed so that we don't hit false positives looking for
987 * insecure pages which are W+X.
993 pr_info("Kernel memory protection disabled.\n");
996 static inline void mark_readonly(void)
998 pr_warn("This architecture does not have kernel memory protection.\n");
1002 static int __ref kernel_init(void *unused)
1006 kernel_init_freeable();
1007 /* need to finish all async __init code before freeing the memory */
1008 async_synchronize_full();
1009 ftrace_free_init_mem();
1012 system_state = SYSTEM_RUNNING;
1013 numa_default_policy();
1015 rcu_end_inkernel_boot();
1017 if (ramdisk_execute_command) {
1018 ret = run_init_process(ramdisk_execute_command);
1021 pr_err("Failed to execute %s (error %d)\n",
1022 ramdisk_execute_command, ret);
1026 * We try each of these until one succeeds.
1028 * The Bourne shell can be used instead of init if we are
1029 * trying to recover a really broken machine.
1031 if (execute_command) {
1032 ret = run_init_process(execute_command);
1035 panic("Requested init %s failed (error %d).",
1036 execute_command, ret);
1038 if (!try_to_run_init_process("/sbin/init") ||
1039 !try_to_run_init_process("/etc/init") ||
1040 !try_to_run_init_process("/bin/init") ||
1041 !try_to_run_init_process("/bin/sh"))
1044 panic("No working init found. Try passing init= option to kernel. "
1045 "See Linux Documentation/admin-guide/init.rst for guidance.");
1048 static noinline void __init kernel_init_freeable(void)
1051 * Wait until kthreadd is all set-up.
1053 wait_for_completion(&kthreadd_done);
1055 /* Now the scheduler is fully set up and can do blocking allocations */
1056 gfp_allowed_mask = __GFP_BITS_MASK;
1059 * init can allocate pages on any node
1061 set_mems_allowed(node_states[N_MEMORY]);
1063 cad_pid = get_pid(task_pid(current));
1065 smp_prepare_cpus(setup_max_cpus);
1069 init_mm_internals();
1071 do_pre_smp_initcalls();
1072 lockup_detector_init();
1077 page_alloc_init_late();
1078 /* Initialize page ext after all struct pages are initialized. */
1083 /* Open the /dev/console on the rootfs, this should never fail */
1084 if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0)
1085 pr_err("Warning: unable to open an initial console.\n");
1090 * check if there is an early userspace init. If yes, let it do all
1094 if (!ramdisk_execute_command)
1095 ramdisk_execute_command = "/init";
1097 if (sys_access((const char __user *) ramdisk_execute_command, 0) != 0) {
1098 ramdisk_execute_command = NULL;
1099 prepare_namespace();
1103 * Ok, we have completed the initial bootup, and
1104 * we're essentially up and running. Get rid of the
1105 * initmem segments and start the user-mode stuff..
1107 * rootfs is available now, try loading the public keys
1108 * and default modules
1111 integrity_load_keys();
1112 load_default_modules();