1 // SPDX-License-Identifier: GPL-2.0-only
5 * Copyright (C) 1991, 1992 Linus Torvalds
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>
13 #define DEBUG /* Enable initcall_debug */
15 #include <linux/types.h>
16 #include <linux/extable.h>
17 #include <linux/module.h>
18 #include <linux/proc_fs.h>
19 #include <linux/binfmts.h>
20 #include <linux/kernel.h>
21 #include <linux/syscalls.h>
22 #include <linux/stackprotector.h>
23 #include <linux/string.h>
24 #include <linux/ctype.h>
25 #include <linux/delay.h>
26 #include <linux/ioport.h>
27 #include <linux/init.h>
28 #include <linux/initrd.h>
29 #include <linux/memblock.h>
30 #include <linux/acpi.h>
31 #include <linux/bootconfig.h>
32 #include <linux/console.h>
33 #include <linux/nmi.h>
34 #include <linux/percpu.h>
35 #include <linux/kmod.h>
36 #include <linux/kprobes.h>
37 #include <linux/kmsan.h>
38 #include <linux/vmalloc.h>
39 #include <linux/kernel_stat.h>
40 #include <linux/start_kernel.h>
41 #include <linux/security.h>
42 #include <linux/smp.h>
43 #include <linux/profile.h>
44 #include <linux/kfence.h>
45 #include <linux/rcupdate.h>
46 #include <linux/srcu.h>
47 #include <linux/moduleparam.h>
48 #include <linux/kallsyms.h>
49 #include <linux/buildid.h>
50 #include <linux/writeback.h>
51 #include <linux/cpu.h>
52 #include <linux/cpuset.h>
53 #include <linux/cgroup.h>
54 #include <linux/efi.h>
55 #include <linux/tick.h>
56 #include <linux/sched/isolation.h>
57 #include <linux/interrupt.h>
58 #include <linux/taskstats_kern.h>
59 #include <linux/delayacct.h>
60 #include <linux/unistd.h>
61 #include <linux/utsname.h>
62 #include <linux/rmap.h>
63 #include <linux/mempolicy.h>
64 #include <linux/key.h>
65 #include <linux/debug_locks.h>
66 #include <linux/debugobjects.h>
67 #include <linux/lockdep.h>
68 #include <linux/kmemleak.h>
69 #include <linux/padata.h>
70 #include <linux/pid_namespace.h>
71 #include <linux/device/driver.h>
72 #include <linux/kthread.h>
73 #include <linux/sched.h>
74 #include <linux/sched/init.h>
75 #include <linux/signal.h>
76 #include <linux/idr.h>
77 #include <linux/kgdb.h>
78 #include <linux/ftrace.h>
79 #include <linux/async.h>
80 #include <linux/shmem_fs.h>
81 #include <linux/slab.h>
82 #include <linux/perf_event.h>
83 #include <linux/ptrace.h>
84 #include <linux/pti.h>
85 #include <linux/blkdev.h>
86 #include <linux/sched/clock.h>
87 #include <linux/sched/task.h>
88 #include <linux/sched/task_stack.h>
89 #include <linux/context_tracking.h>
90 #include <linux/random.h>
91 #include <linux/list.h>
92 #include <linux/integrity.h>
93 #include <linux/proc_ns.h>
95 #include <linux/cache.h>
96 #include <linux/rodata_test.h>
97 #include <linux/jump_label.h>
98 #include <linux/kcsan.h>
99 #include <linux/init_syscalls.h>
100 #include <linux/stackdepot.h>
101 #include <linux/randomize_kstack.h>
102 #include <net/net_namespace.h>
105 #include <asm/setup.h>
106 #include <asm/sections.h>
107 #include <asm/cacheflush.h>
109 #define CREATE_TRACE_POINTS
110 #include <trace/events/initcall.h>
112 #include <kunit/test.h>
114 static int kernel_init(void *);
117 * Debug helper: via this flag we know that we are in 'early bootup code'
118 * where only the boot processor is running with IRQ disabled. This means
119 * two things - IRQ must not be enabled before the flag is cleared and some
120 * operations which are not allowed with IRQ disabled are allowed while the
123 bool early_boot_irqs_disabled __read_mostly
;
125 enum system_states system_state __read_mostly
;
126 EXPORT_SYMBOL(system_state
);
129 * Boot command-line arguments
131 #define MAX_INIT_ARGS CONFIG_INIT_ENV_ARG_LIMIT
132 #define MAX_INIT_ENVS CONFIG_INIT_ENV_ARG_LIMIT
134 /* Default late time init is NULL. archs can override this later. */
135 void (*__initdata late_time_init
)(void);
137 /* Untouched command line saved by arch-specific code. */
138 char __initdata boot_command_line
[COMMAND_LINE_SIZE
];
139 /* Untouched saved command line (eg. for /proc) */
140 char *saved_command_line __ro_after_init
;
141 unsigned int saved_command_line_len __ro_after_init
;
142 /* Command line for parameter parsing */
143 static char *static_command_line
;
144 /* Untouched extra command line */
145 static char *extra_command_line
;
146 /* Extra init arguments */
147 static char *extra_init_args
;
149 #ifdef CONFIG_BOOT_CONFIG
150 /* Is bootconfig on command line? */
151 static bool bootconfig_found
;
152 static size_t initargs_offs
;
154 # define bootconfig_found false
155 # define initargs_offs 0
158 static char *execute_command
;
159 static char *ramdisk_execute_command
= "/init";
162 * Used to generate warnings if static_key manipulation functions are used
163 * before jump_label_init is called.
165 bool static_key_initialized __read_mostly
;
166 EXPORT_SYMBOL_GPL(static_key_initialized
);
169 * If set, this is an indication to the drivers that reset the underlying
170 * device before going ahead with the initialization otherwise driver might
171 * rely on the BIOS and skip the reset operation.
173 * This is useful if kernel is booting in an unreliable environment.
174 * For ex. kdump situation where previous kernel has crashed, BIOS has been
175 * skipped and devices will be in unknown state.
177 unsigned int reset_devices
;
178 EXPORT_SYMBOL(reset_devices
);
180 static int __init
set_reset_devices(char *str
)
186 __setup("reset_devices", set_reset_devices
);
188 static const char *argv_init
[MAX_INIT_ARGS
+2] = { "init", NULL
, };
189 const char *envp_init
[MAX_INIT_ENVS
+2] = { "HOME=/", "TERM=linux", NULL
, };
190 static const char *panic_later
, *panic_param
;
192 static bool __init
obsolete_checksetup(char *line
)
194 const struct obs_kernel_param
*p
;
195 bool had_early_param
= false;
199 int n
= strlen(p
->str
);
200 if (parameqn(line
, p
->str
, n
)) {
202 /* Already done in parse_early_param?
203 * (Needs exact match on param part).
204 * Keep iterating, as we can have early
205 * params and __setups of same names 8( */
206 if (line
[n
] == '\0' || line
[n
] == '=')
207 had_early_param
= true;
208 } else if (!p
->setup_func
) {
209 pr_warn("Parameter %s is obsolete, ignored\n",
212 } else if (p
->setup_func(line
+ n
))
216 } while (p
< __setup_end
);
218 return had_early_param
;
222 * This should be approx 2 Bo*oMips to start (note initial shift), and will
223 * still work even if initially too large, it will just take slightly longer
225 unsigned long loops_per_jiffy
= (1<<12);
226 EXPORT_SYMBOL(loops_per_jiffy
);
228 static int __init
debug_kernel(char *str
)
230 console_loglevel
= CONSOLE_LOGLEVEL_DEBUG
;
234 static int __init
quiet_kernel(char *str
)
236 console_loglevel
= CONSOLE_LOGLEVEL_QUIET
;
240 early_param("debug", debug_kernel
);
241 early_param("quiet", quiet_kernel
);
243 static int __init
loglevel(char *str
)
248 * Only update loglevel value when a correct setting was passed,
249 * to prevent blind crashes (when loglevel being set to 0) that
250 * are quite hard to debug
252 if (get_option(&str
, &newlevel
)) {
253 console_loglevel
= newlevel
;
260 early_param("loglevel", loglevel
);
262 #ifdef CONFIG_BLK_DEV_INITRD
263 static void * __init
get_boot_config_from_initrd(size_t *_size
)
273 data
= (char *)initrd_end
- BOOTCONFIG_MAGIC_LEN
;
275 * Since Grub may align the size of initrd to 4, we must
276 * check the preceding 3 bytes as well.
278 for (i
= 0; i
< 4; i
++) {
279 if (!memcmp(data
, BOOTCONFIG_MAGIC
, BOOTCONFIG_MAGIC_LEN
))
286 hdr
= (u32
*)(data
- 8);
287 size
= le32_to_cpu(hdr
[0]);
288 csum
= le32_to_cpu(hdr
[1]);
290 data
= ((void *)hdr
) - size
;
291 if ((unsigned long)data
< initrd_start
) {
292 pr_err("bootconfig size %d is greater than initrd size %ld\n",
293 size
, initrd_end
- initrd_start
);
297 if (xbc_calc_checksum(data
, size
) != csum
) {
298 pr_err("bootconfig checksum failed\n");
302 /* Remove bootconfig from initramfs/initrd */
303 initrd_end
= (unsigned long)data
;
310 static void * __init
get_boot_config_from_initrd(size_t *_size
)
316 #ifdef CONFIG_BOOT_CONFIG
318 static char xbc_namebuf
[XBC_KEYLEN_MAX
] __initdata
;
320 #define rest(dst, end) ((end) > (dst) ? (end) - (dst) : 0)
322 static int __init
xbc_snprint_cmdline(char *buf
, size_t size
,
323 struct xbc_node
*root
)
325 struct xbc_node
*knode
, *vnode
;
326 char *end
= buf
+ size
;
330 xbc_node_for_each_key_value(root
, knode
, val
) {
331 ret
= xbc_node_compose_key_after(root
, knode
,
332 xbc_namebuf
, XBC_KEYLEN_MAX
);
336 vnode
= xbc_node_get_child(knode
);
338 ret
= snprintf(buf
, rest(buf
, end
), "%s ", xbc_namebuf
);
344 xbc_array_for_each_value(vnode
, val
) {
345 ret
= snprintf(buf
, rest(buf
, end
), "%s=\"%s\" ",
353 return buf
- (end
- size
);
357 /* Make an extra command line under given key word */
358 static char * __init
xbc_make_cmdline(const char *key
)
360 struct xbc_node
*root
;
364 root
= xbc_find_node(key
);
368 /* Count required buffer size */
369 len
= xbc_snprint_cmdline(NULL
, 0, root
);
373 new_cmdline
= memblock_alloc(len
+ 1, SMP_CACHE_BYTES
);
375 pr_err("Failed to allocate memory for extra kernel cmdline.\n");
379 ret
= xbc_snprint_cmdline(new_cmdline
, len
+ 1, root
);
380 if (ret
< 0 || ret
> len
) {
381 pr_err("Failed to print extra kernel cmdline.\n");
382 memblock_free(new_cmdline
, len
+ 1);
389 static int __init
bootconfig_params(char *param
, char *val
,
390 const char *unused
, void *arg
)
392 if (strcmp(param
, "bootconfig") == 0) {
393 bootconfig_found
= true;
398 static int __init
warn_bootconfig(char *str
)
400 /* The 'bootconfig' has been handled by bootconfig_params(). */
404 static void __init
setup_boot_config(void)
406 static char tmp_cmdline
[COMMAND_LINE_SIZE
] __initdata
;
407 const char *msg
, *data
;
412 /* Cut out the bootconfig data even if we have no bootconfig option */
413 data
= get_boot_config_from_initrd(&size
);
414 /* If there is no bootconfig in initrd, try embedded one. */
416 data
= xbc_get_embedded_bootconfig(&size
);
418 strscpy(tmp_cmdline
, boot_command_line
, COMMAND_LINE_SIZE
);
419 err
= parse_args("bootconfig", tmp_cmdline
, NULL
, 0, 0, 0, NULL
,
422 if (IS_ERR(err
) || !(bootconfig_found
|| IS_ENABLED(CONFIG_BOOT_CONFIG_FORCE
)))
425 /* parse_args() stops at the next param of '--' and returns an address */
427 initargs_offs
= err
- tmp_cmdline
;
430 /* If user intended to use bootconfig, show an error level message */
431 if (bootconfig_found
)
432 pr_err("'bootconfig' found on command line, but no bootconfig found\n");
434 pr_info("No bootconfig data provided, so skipping bootconfig");
438 if (size
>= XBC_DATA_MAX
) {
439 pr_err("bootconfig size %ld greater than max size %d\n",
440 (long)size
, XBC_DATA_MAX
);
444 ret
= xbc_init(data
, size
, &msg
, &pos
);
447 pr_err("Failed to init bootconfig: %s.\n", msg
);
449 pr_err("Failed to parse bootconfig: %s at %d.\n",
452 xbc_get_info(&ret
, NULL
);
453 pr_info("Load bootconfig: %ld bytes %d nodes\n", (long)size
, ret
);
454 /* keys starting with "kernel." are passed via cmdline */
455 extra_command_line
= xbc_make_cmdline("kernel");
456 /* Also, "init." keys are init arguments */
457 extra_init_args
= xbc_make_cmdline("init");
462 static void __init
exit_boot_config(void)
467 #else /* !CONFIG_BOOT_CONFIG */
469 static void __init
setup_boot_config(void)
471 /* Remove bootconfig data from initrd */
472 get_boot_config_from_initrd(NULL
);
475 static int __init
warn_bootconfig(char *str
)
477 pr_warn("WARNING: 'bootconfig' found on the kernel command line but CONFIG_BOOT_CONFIG is not set.\n");
481 #define exit_boot_config() do {} while (0)
483 #endif /* CONFIG_BOOT_CONFIG */
485 early_param("bootconfig", warn_bootconfig
);
487 /* Change NUL term back to "=", to make "param" the whole string. */
488 static void __init
repair_env_string(char *param
, char *val
)
491 /* param=val or param="val"? */
492 if (val
== param
+strlen(param
)+1)
494 else if (val
== param
+strlen(param
)+2) {
496 memmove(val
-1, val
, strlen(val
)+1);
502 /* Anything after -- gets handed straight to init. */
503 static int __init
set_init_arg(char *param
, char *val
,
504 const char *unused
, void *arg
)
511 repair_env_string(param
, val
);
513 for (i
= 0; argv_init
[i
]; i
++) {
514 if (i
== MAX_INIT_ARGS
) {
515 panic_later
= "init";
520 argv_init
[i
] = param
;
525 * Unknown boot options get handed to init, unless they look like
526 * unused parameters (modprobe will find them in /proc/cmdline).
528 static int __init
unknown_bootoption(char *param
, char *val
,
529 const char *unused
, void *arg
)
531 size_t len
= strlen(param
);
533 /* Handle params aliased to sysctls */
534 if (sysctl_is_alias(param
))
537 repair_env_string(param
, val
);
539 /* Handle obsolete-style parameters */
540 if (obsolete_checksetup(param
))
543 /* Unused module parameter. */
544 if (strnchr(param
, len
, '.'))
551 /* Environment option */
553 for (i
= 0; envp_init
[i
]; i
++) {
554 if (i
== MAX_INIT_ENVS
) {
558 if (!strncmp(param
, envp_init
[i
], len
+1))
561 envp_init
[i
] = param
;
563 /* Command line option */
565 for (i
= 0; argv_init
[i
]; i
++) {
566 if (i
== MAX_INIT_ARGS
) {
567 panic_later
= "init";
571 argv_init
[i
] = param
;
576 static int __init
init_setup(char *str
)
580 execute_command
= str
;
582 * In case LILO is going to boot us with default command line,
583 * it prepends "auto" before the whole cmdline which makes
584 * the shell think it should execute a script with such name.
585 * So we ignore all arguments entered _before_ init=... [MJ]
587 for (i
= 1; i
< MAX_INIT_ARGS
; i
++)
591 __setup("init=", init_setup
);
593 static int __init
rdinit_setup(char *str
)
597 ramdisk_execute_command
= str
;
598 /* See "auto" comment in init_setup */
599 for (i
= 1; i
< MAX_INIT_ARGS
; i
++)
603 __setup("rdinit=", rdinit_setup
);
606 static const unsigned int setup_max_cpus
= NR_CPUS
;
607 static inline void setup_nr_cpu_ids(void) { }
608 static inline void smp_prepare_cpus(unsigned int maxcpus
) { }
612 * We need to store the untouched command line for future reference.
613 * We also need to store the touched command line since the parameter
614 * parsing is performed in place, and we should allow a component to
615 * store reference of name/value for future reference.
617 static void __init
setup_command_line(char *command_line
)
619 size_t len
, xlen
= 0, ilen
= 0;
621 if (extra_command_line
)
622 xlen
= strlen(extra_command_line
);
624 ilen
= strlen(extra_init_args
) + 4; /* for " -- " */
626 len
= xlen
+ strlen(boot_command_line
) + 1;
628 saved_command_line
= memblock_alloc(len
+ ilen
, SMP_CACHE_BYTES
);
629 if (!saved_command_line
)
630 panic("%s: Failed to allocate %zu bytes\n", __func__
, len
+ ilen
);
632 static_command_line
= memblock_alloc(len
, SMP_CACHE_BYTES
);
633 if (!static_command_line
)
634 panic("%s: Failed to allocate %zu bytes\n", __func__
, len
);
638 * We have to put extra_command_line before boot command
639 * lines because there could be dashes (separator of init
640 * command line) in the command lines.
642 strcpy(saved_command_line
, extra_command_line
);
643 strcpy(static_command_line
, extra_command_line
);
645 strcpy(saved_command_line
+ xlen
, boot_command_line
);
646 strcpy(static_command_line
+ xlen
, command_line
);
650 * Append supplemental init boot args to saved_command_line
651 * so that user can check what command line options passed
653 * The order should always be
654 * " -- "[bootconfig init-param][cmdline init-param]
657 len
= xlen
+ initargs_offs
;
658 strcpy(saved_command_line
+ len
, extra_init_args
);
659 len
+= ilen
- 4; /* strlen(extra_init_args) */
660 strcpy(saved_command_line
+ len
,
661 boot_command_line
+ initargs_offs
- 1);
663 len
= strlen(saved_command_line
);
664 strcpy(saved_command_line
+ len
, " -- ");
666 strcpy(saved_command_line
+ len
, extra_init_args
);
670 saved_command_line_len
= strlen(saved_command_line
);
674 * We need to finalize in a non-__init function or else race conditions
675 * between the root thread and the init thread may cause start_kernel to
676 * be reaped by free_initmem before the root thread has proceeded to
679 * gcc-3.4 accidentally inlines this function, so use noinline.
682 static __initdata
DECLARE_COMPLETION(kthreadd_done
);
684 noinline
void __ref __noreturn
rest_init(void)
686 struct task_struct
*tsk
;
689 rcu_scheduler_starting();
691 * We need to spawn init first so that it obtains pid 1, however
692 * the init task will end up wanting to create kthreads, which, if
693 * we schedule it before we create kthreadd, will OOPS.
695 pid
= user_mode_thread(kernel_init
, NULL
, CLONE_FS
);
697 * Pin init on the boot CPU. Task migration is not properly working
698 * until sched_init_smp() has been run. It will set the allowed
699 * CPUs for init to the non isolated CPUs.
702 tsk
= find_task_by_pid_ns(pid
, &init_pid_ns
);
703 tsk
->flags
|= PF_NO_SETAFFINITY
;
704 set_cpus_allowed_ptr(tsk
, cpumask_of(smp_processor_id()));
707 numa_default_policy();
708 pid
= kernel_thread(kthreadd
, NULL
, NULL
, CLONE_FS
| CLONE_FILES
);
710 kthreadd_task
= find_task_by_pid_ns(pid
, &init_pid_ns
);
714 * Enable might_sleep() and smp_processor_id() checks.
715 * They cannot be enabled earlier because with CONFIG_PREEMPTION=y
716 * kernel_thread() would trigger might_sleep() splats. With
717 * CONFIG_PREEMPT_VOLUNTARY=y the init task might have scheduled
718 * already, but it's stuck on the kthreadd_done completion.
720 system_state
= SYSTEM_SCHEDULING
;
722 complete(&kthreadd_done
);
725 * The boot idle thread must execute schedule()
726 * at least once to get things moving:
728 schedule_preempt_disabled();
729 /* Call into cpu_idle with preempt disabled */
730 cpu_startup_entry(CPUHP_ONLINE
);
733 /* Check for early params. */
734 static int __init
do_early_param(char *param
, char *val
,
735 const char *unused
, void *arg
)
737 const struct obs_kernel_param
*p
;
739 for (p
= __setup_start
; p
< __setup_end
; p
++) {
740 if ((p
->early
&& parameq(param
, p
->str
)) ||
741 (strcmp(param
, "console") == 0 &&
742 strcmp(p
->str
, "earlycon") == 0)
744 if (p
->setup_func(val
) != 0)
745 pr_warn("Malformed early option '%s'\n", param
);
748 /* We accept everything at this stage. */
752 void __init
parse_early_options(char *cmdline
)
754 parse_args("early options", cmdline
, NULL
, 0, 0, 0, NULL
,
758 /* Arch code calls this early on, or if not, just before other parsing. */
759 void __init
parse_early_param(void)
761 static int done __initdata
;
762 static char tmp_cmdline
[COMMAND_LINE_SIZE
] __initdata
;
767 /* All fall through to do_early_param. */
768 strscpy(tmp_cmdline
, boot_command_line
, COMMAND_LINE_SIZE
);
769 parse_early_options(tmp_cmdline
);
773 void __init __weak
arch_post_acpi_subsys_init(void) { }
775 void __init __weak
smp_setup_processor_id(void)
779 # if THREAD_SIZE >= PAGE_SIZE
780 void __init __weak
thread_stack_cache_init(void)
785 void __init __weak
poking_init(void) { }
787 void __init __weak
pgtable_cache_init(void) { }
789 void __init __weak
trap_init(void) { }
792 core_param(initcall_debug
, initcall_debug
, bool, 0644);
794 #ifdef TRACEPOINTS_ENABLED
795 static void __init
initcall_debug_enable(void);
797 static inline void initcall_debug_enable(void)
802 #ifdef CONFIG_RANDOMIZE_KSTACK_OFFSET
803 DEFINE_STATIC_KEY_MAYBE_RO(CONFIG_RANDOMIZE_KSTACK_OFFSET_DEFAULT
,
804 randomize_kstack_offset
);
805 DEFINE_PER_CPU(u32
, kstack_offset
);
807 static int __init
early_randomize_kstack_offset(char *buf
)
812 ret
= kstrtobool(buf
, &bool_result
);
817 static_branch_enable(&randomize_kstack_offset
);
819 static_branch_disable(&randomize_kstack_offset
);
822 early_param("randomize_kstack_offset", early_randomize_kstack_offset
);
825 void __init __weak __noreturn
arch_call_rest_init(void)
830 static void __init
print_unknown_bootoptions(void)
832 char *unknown_options
;
834 const char *const *p
;
837 if (panic_later
|| (!argv_init
[1] && !envp_init
[2]))
841 * Determine how many options we have to print out, plus a space
844 len
= 1; /* null terminator */
845 for (p
= &argv_init
[1]; *p
; p
++) {
849 for (p
= &envp_init
[2]; *p
; p
++) {
854 unknown_options
= memblock_alloc(len
, SMP_CACHE_BYTES
);
855 if (!unknown_options
) {
856 pr_err("%s: Failed to allocate %zu bytes\n",
860 end
= unknown_options
;
862 for (p
= &argv_init
[1]; *p
; p
++)
863 end
+= sprintf(end
, " %s", *p
);
864 for (p
= &envp_init
[2]; *p
; p
++)
865 end
+= sprintf(end
, " %s", *p
);
867 /* Start at unknown_options[1] to skip the initial space */
868 pr_notice("Unknown kernel command line parameters \"%s\", will be passed to user space.\n",
869 &unknown_options
[1]);
870 memblock_free(unknown_options
, len
);
873 asmlinkage __visible __init __no_sanitize_address __noreturn __no_stack_protector
874 void start_kernel(void)
879 set_task_stack_end_magic(&init_task
);
880 smp_setup_processor_id();
881 debug_objects_early_init();
882 init_vmlinux_build_id();
887 early_boot_irqs_disabled
= true;
890 * Interrupts are still disabled. Do necessary setups, then
895 pr_notice("%s", linux_banner
);
896 early_security_init();
897 setup_arch(&command_line
);
899 setup_command_line(command_line
);
901 setup_per_cpu_areas();
902 smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */
903 boot_cpu_hotplug_init();
905 pr_notice("Kernel command line: %s\n", saved_command_line
);
906 /* parameters may set static keys */
909 after_dashes
= parse_args("Booting kernel",
910 static_command_line
, __start___param
,
911 __stop___param
- __start___param
,
912 -1, -1, NULL
, &unknown_bootoption
);
913 print_unknown_bootoptions();
914 if (!IS_ERR_OR_NULL(after_dashes
))
915 parse_args("Setting init args", after_dashes
, NULL
, 0, -1, -1,
918 parse_args("Setting extra init args", extra_init_args
,
919 NULL
, 0, -1, -1, NULL
, set_init_arg
);
921 /* Architectural and non-timekeeping rng init, before allocator init */
922 random_init_early(command_line
);
925 * These use large bootmem allocations and must precede
926 * initalization of page allocator
929 vfs_caches_init_early();
936 /* trace_printk can be enabled here */
940 * Set up the scheduler prior starting any interrupts (such as the
941 * timer interrupt). Full topology setup happens at smp_init()
942 * time - but meanwhile we still have a functioning scheduler.
946 if (WARN(!irqs_disabled(),
947 "Interrupts were enabled *very* early, fixing it\n"))
953 * Set up housekeeping before setting up workqueues to allow the unbound
954 * workqueue to take non-housekeeping into account.
959 * Allow workqueue creation and work item queueing/cancelling
960 * early. Work item execution depends on kthreads and starts after
963 workqueue_init_early();
967 /* Trace events are available after this */
971 initcall_debug_enable();
973 context_tracking_init();
974 /* init some links before init_ISA_irqs() */
986 /* This must be after timekeeping is initialized */
989 /* These make use of the fully initialized rng */
991 boot_init_stack_canary();
995 call_function_init();
996 WARN(!irqs_disabled(), "Interrupts were enabled early\n");
998 early_boot_irqs_disabled
= false;
1001 kmem_cache_init_late();
1004 * HACK ALERT! This is early. We're enabling the console before
1005 * we've done PCI setups etc, and console_init() must be aware of
1006 * this. But we do want output early, in case something goes wrong.
1010 panic("Too many boot %s vars at `%s'", panic_later
,
1016 * Need to run this when irqs are enabled, because it wants
1017 * to self-test [hard/soft]-irqs on/off lock inversion bugs
1022 #ifdef CONFIG_BLK_DEV_INITRD
1023 if (initrd_start
&& !initrd_below_start_ok
&&
1024 page_to_pfn(virt_to_page((void *)initrd_start
)) < min_low_pfn
) {
1025 pr_crit("initrd overwritten (0x%08lx < 0x%08lx) - disabling it.\n",
1026 page_to_pfn(virt_to_page((void *)initrd_start
)),
1031 setup_per_cpu_pageset();
1039 arch_cpu_finalize_init();
1044 if (efi_enabled(EFI_RUNTIME_SERVICES
))
1045 efi_enter_virtual_mode();
1047 thread_stack_cache_init();
1064 taskstats_init_early();
1067 acpi_subsystem_init();
1068 arch_post_acpi_subsys_init();
1071 /* Do the rest non-__init'ed, we're now alive */
1072 arch_call_rest_init();
1075 * Avoid stack canaries in callers of boot_init_stack_canary for gcc-10
1078 #if !__has_attribute(__no_stack_protector__)
1079 prevent_tail_call_optimization();
1083 /* Call all constructor functions linked into the kernel. */
1084 static void __init
do_ctors(void)
1087 * For UML, the constructors have already been called by the
1088 * normal setup code as it's just a normal ELF binary, so we
1089 * cannot do it again - but we do need CONFIG_CONSTRUCTORS
1090 * even on UML for modules.
1092 #if defined(CONFIG_CONSTRUCTORS) && !defined(CONFIG_UML)
1093 ctor_fn_t
*fn
= (ctor_fn_t
*) __ctors_start
;
1095 for (; fn
< (ctor_fn_t
*) __ctors_end
; fn
++)
1100 #ifdef CONFIG_KALLSYMS
1101 struct blacklist_entry
{
1102 struct list_head next
;
1106 static __initdata_or_module
LIST_HEAD(blacklisted_initcalls
);
1108 static int __init
initcall_blacklist(char *str
)
1111 struct blacklist_entry
*entry
;
1113 /* str argument is a comma-separated list of functions */
1115 str_entry
= strsep(&str
, ",");
1117 pr_debug("blacklisting initcall %s\n", str_entry
);
1118 entry
= memblock_alloc(sizeof(*entry
),
1121 panic("%s: Failed to allocate %zu bytes\n",
1122 __func__
, sizeof(*entry
));
1123 entry
->buf
= memblock_alloc(strlen(str_entry
) + 1,
1126 panic("%s: Failed to allocate %zu bytes\n",
1127 __func__
, strlen(str_entry
) + 1);
1128 strcpy(entry
->buf
, str_entry
);
1129 list_add(&entry
->next
, &blacklisted_initcalls
);
1131 } while (str_entry
);
1136 static bool __init_or_module
initcall_blacklisted(initcall_t fn
)
1138 struct blacklist_entry
*entry
;
1139 char fn_name
[KSYM_SYMBOL_LEN
];
1142 if (list_empty(&blacklisted_initcalls
))
1145 addr
= (unsigned long) dereference_function_descriptor(fn
);
1146 sprint_symbol_no_offset(fn_name
, addr
);
1149 * fn will be "function_name [module_name]" where [module_name] is not
1150 * displayed for built-in init functions. Strip off the [module_name].
1152 strreplace(fn_name
, ' ', '\0');
1154 list_for_each_entry(entry
, &blacklisted_initcalls
, next
) {
1155 if (!strcmp(fn_name
, entry
->buf
)) {
1156 pr_debug("initcall %s blacklisted\n", fn_name
);
1164 static int __init
initcall_blacklist(char *str
)
1166 pr_warn("initcall_blacklist requires CONFIG_KALLSYMS\n");
1170 static bool __init_or_module
initcall_blacklisted(initcall_t fn
)
1175 __setup("initcall_blacklist=", initcall_blacklist
);
1177 static __init_or_module
void
1178 trace_initcall_start_cb(void *data
, initcall_t fn
)
1180 ktime_t
*calltime
= data
;
1182 printk(KERN_DEBUG
"calling %pS @ %i\n", fn
, task_pid_nr(current
));
1183 *calltime
= ktime_get();
1186 static __init_or_module
void
1187 trace_initcall_finish_cb(void *data
, initcall_t fn
, int ret
)
1189 ktime_t rettime
, *calltime
= data
;
1191 rettime
= ktime_get();
1192 printk(KERN_DEBUG
"initcall %pS returned %d after %lld usecs\n",
1193 fn
, ret
, (unsigned long long)ktime_us_delta(rettime
, *calltime
));
1196 static ktime_t initcall_calltime
;
1198 #ifdef TRACEPOINTS_ENABLED
1199 static void __init
initcall_debug_enable(void)
1203 ret
= register_trace_initcall_start(trace_initcall_start_cb
,
1204 &initcall_calltime
);
1205 ret
|= register_trace_initcall_finish(trace_initcall_finish_cb
,
1206 &initcall_calltime
);
1207 WARN(ret
, "Failed to register initcall tracepoints\n");
1209 # define do_trace_initcall_start trace_initcall_start
1210 # define do_trace_initcall_finish trace_initcall_finish
1212 static inline void do_trace_initcall_start(initcall_t fn
)
1214 if (!initcall_debug
)
1216 trace_initcall_start_cb(&initcall_calltime
, fn
);
1218 static inline void do_trace_initcall_finish(initcall_t fn
, int ret
)
1220 if (!initcall_debug
)
1222 trace_initcall_finish_cb(&initcall_calltime
, fn
, ret
);
1224 #endif /* !TRACEPOINTS_ENABLED */
1226 int __init_or_module
do_one_initcall(initcall_t fn
)
1228 int count
= preempt_count();
1232 if (initcall_blacklisted(fn
))
1235 do_trace_initcall_start(fn
);
1237 do_trace_initcall_finish(fn
, ret
);
1241 if (preempt_count() != count
) {
1242 sprintf(msgbuf
, "preemption imbalance ");
1243 preempt_count_set(count
);
1245 if (irqs_disabled()) {
1246 strlcat(msgbuf
, "disabled interrupts ", sizeof(msgbuf
));
1249 WARN(msgbuf
[0], "initcall %pS returned with %s\n", fn
, msgbuf
);
1251 add_latent_entropy();
1256 static initcall_entry_t
*initcall_levels
[] __initdata
= {
1268 /* Keep these in sync with initcalls in include/linux/init.h */
1269 static const char *initcall_level_names
[] __initdata
= {
1280 static int __init
ignore_unknown_bootoption(char *param
, char *val
,
1281 const char *unused
, void *arg
)
1286 static void __init
do_initcall_level(int level
, char *command_line
)
1288 initcall_entry_t
*fn
;
1290 parse_args(initcall_level_names
[level
],
1291 command_line
, __start___param
,
1292 __stop___param
- __start___param
,
1294 NULL
, ignore_unknown_bootoption
);
1296 trace_initcall_level(initcall_level_names
[level
]);
1297 for (fn
= initcall_levels
[level
]; fn
< initcall_levels
[level
+1]; fn
++)
1298 do_one_initcall(initcall_from_entry(fn
));
1301 static void __init
do_initcalls(void)
1304 size_t len
= saved_command_line_len
+ 1;
1307 command_line
= kzalloc(len
, GFP_KERNEL
);
1309 panic("%s: Failed to allocate %zu bytes\n", __func__
, len
);
1311 for (level
= 0; level
< ARRAY_SIZE(initcall_levels
) - 1; level
++) {
1312 /* Parser modifies command_line, restore it each time */
1313 strcpy(command_line
, saved_command_line
);
1314 do_initcall_level(level
, command_line
);
1317 kfree(command_line
);
1321 * Ok, the machine is now initialized. None of the devices
1322 * have been touched yet, but the CPU subsystem is up and
1323 * running, and memory and process management works.
1325 * Now we can finally start doing some real work..
1327 static void __init
do_basic_setup(void)
1336 static void __init
do_pre_smp_initcalls(void)
1338 initcall_entry_t
*fn
;
1340 trace_initcall_level("early");
1341 for (fn
= __initcall_start
; fn
< __initcall0_start
; fn
++)
1342 do_one_initcall(initcall_from_entry(fn
));
1345 static int run_init_process(const char *init_filename
)
1347 const char *const *p
;
1349 argv_init
[0] = init_filename
;
1350 pr_info("Run %s as init process\n", init_filename
);
1351 pr_debug(" with arguments:\n");
1352 for (p
= argv_init
; *p
; p
++)
1353 pr_debug(" %s\n", *p
);
1354 pr_debug(" with environment:\n");
1355 for (p
= envp_init
; *p
; p
++)
1356 pr_debug(" %s\n", *p
);
1357 return kernel_execve(init_filename
, argv_init
, envp_init
);
1360 static int try_to_run_init_process(const char *init_filename
)
1364 ret
= run_init_process(init_filename
);
1366 if (ret
&& ret
!= -ENOENT
) {
1367 pr_err("Starting init: %s exists but couldn't execute it (error %d)\n",
1368 init_filename
, ret
);
1374 static noinline
void __init
kernel_init_freeable(void);
1376 #if defined(CONFIG_STRICT_KERNEL_RWX) || defined(CONFIG_STRICT_MODULE_RWX)
1377 bool rodata_enabled __ro_after_init
= true;
1379 #ifndef arch_parse_debug_rodata
1380 static inline bool arch_parse_debug_rodata(char *str
) { return false; }
1383 static int __init
set_debug_rodata(char *str
)
1385 if (arch_parse_debug_rodata(str
))
1388 if (str
&& !strcmp(str
, "on"))
1389 rodata_enabled
= true;
1390 else if (str
&& !strcmp(str
, "off"))
1391 rodata_enabled
= false;
1393 pr_warn("Invalid option string for rodata: '%s'\n", str
);
1396 early_param("rodata", set_debug_rodata
);
1399 #ifdef CONFIG_STRICT_KERNEL_RWX
1400 static void mark_readonly(void)
1402 if (rodata_enabled
) {
1404 * load_module() results in W+X mappings, which are cleaned
1405 * up with call_rcu(). Let's make sure that queued work is
1406 * flushed so that we don't hit false positives looking for
1407 * insecure pages which are W+X.
1413 pr_info("Kernel memory protection disabled.\n");
1415 #elif defined(CONFIG_ARCH_HAS_STRICT_KERNEL_RWX)
1416 static inline void mark_readonly(void)
1418 pr_warn("Kernel memory protection not selected by kernel config.\n");
1421 static inline void mark_readonly(void)
1423 pr_warn("This architecture does not have kernel memory protection.\n");
1427 void __weak
free_initmem(void)
1429 free_initmem_default(POISON_FREE_INITMEM
);
1432 static int __ref
kernel_init(void *unused
)
1437 * Wait until kthreadd is all set-up.
1439 wait_for_completion(&kthreadd_done
);
1441 kernel_init_freeable();
1442 /* need to finish all async __init code before freeing the memory */
1443 async_synchronize_full();
1445 system_state
= SYSTEM_FREEING_INITMEM
;
1446 kprobe_free_init_mem();
1447 ftrace_free_init_mem();
1448 kgdb_free_init_mem();
1454 * Kernel mappings are now finalized - update the userspace page-table
1459 system_state
= SYSTEM_RUNNING
;
1460 numa_default_policy();
1462 rcu_end_inkernel_boot();
1466 if (ramdisk_execute_command
) {
1467 ret
= run_init_process(ramdisk_execute_command
);
1470 pr_err("Failed to execute %s (error %d)\n",
1471 ramdisk_execute_command
, ret
);
1475 * We try each of these until one succeeds.
1477 * The Bourne shell can be used instead of init if we are
1478 * trying to recover a really broken machine.
1480 if (execute_command
) {
1481 ret
= run_init_process(execute_command
);
1484 panic("Requested init %s failed (error %d).",
1485 execute_command
, ret
);
1488 if (CONFIG_DEFAULT_INIT
[0] != '\0') {
1489 ret
= run_init_process(CONFIG_DEFAULT_INIT
);
1491 pr_err("Default init %s failed (error %d)\n",
1492 CONFIG_DEFAULT_INIT
, ret
);
1497 if (!try_to_run_init_process("/sbin/init") ||
1498 !try_to_run_init_process("/etc/init") ||
1499 !try_to_run_init_process("/bin/init") ||
1500 !try_to_run_init_process("/bin/sh"))
1503 panic("No working init found. Try passing init= option to kernel. "
1504 "See Linux Documentation/admin-guide/init.rst for guidance.");
1507 /* Open /dev/console, for stdin/stdout/stderr, this should never fail */
1508 void __init
console_on_rootfs(void)
1510 struct file
*file
= filp_open("/dev/console", O_RDWR
, 0);
1513 pr_err("Warning: unable to open an initial console.\n");
1522 static noinline
void __init
kernel_init_freeable(void)
1524 /* Now the scheduler is fully set up and can do blocking allocations */
1525 gfp_allowed_mask
= __GFP_BITS_MASK
;
1528 * init can allocate pages on any node
1530 set_mems_allowed(node_states
[N_MEMORY
]);
1532 cad_pid
= get_pid(task_pid(current
));
1534 smp_prepare_cpus(setup_max_cpus
);
1538 init_mm_internals();
1540 rcu_init_tasks_generic();
1541 do_pre_smp_initcalls();
1542 lockup_detector_init();
1547 workqueue_init_topology();
1549 page_alloc_init_late();
1553 kunit_run_all_tests();
1555 wait_for_initramfs();
1556 console_on_rootfs();
1559 * check if there is an early userspace init. If yes, let it do all
1562 if (init_eaccess(ramdisk_execute_command
) != 0) {
1563 ramdisk_execute_command
= NULL
;
1564 prepare_namespace();
1568 * Ok, we have completed the initial bootup, and
1569 * we're essentially up and running. Get rid of the
1570 * initmem segments and start the user-mode stuff..
1572 * rootfs is available now, try loading the public keys
1573 * and default modules
1576 integrity_load_keys();