Version:  2.0.40 2.2.26 2.4.37 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18 3.19 4.0 4.1 4.2

Linux/init/main.c

  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 #define DEBUG           /* Enable initcall_debug */
 13 
 14 #include <linux/types.h>
 15 #include <linux/module.h>
 16 #include <linux/proc_fs.h>
 17 #include <linux/kernel.h>
 18 #include <linux/syscalls.h>
 19 #include <linux/stackprotector.h>
 20 #include <linux/string.h>
 21 #include <linux/ctype.h>
 22 #include <linux/delay.h>
 23 #include <linux/ioport.h>
 24 #include <linux/init.h>
 25 #include <linux/initrd.h>
 26 #include <linux/bootmem.h>
 27 #include <linux/acpi.h>
 28 #include <linux/tty.h>
 29 #include <linux/percpu.h>
 30 #include <linux/kmod.h>
 31 #include <linux/vmalloc.h>
 32 #include <linux/kernel_stat.h>
 33 #include <linux/start_kernel.h>
 34 #include <linux/security.h>
 35 #include <linux/smp.h>
 36 #include <linux/profile.h>
 37 #include <linux/rcupdate.h>
 38 #include <linux/moduleparam.h>
 39 #include <linux/kallsyms.h>
 40 #include <linux/writeback.h>
 41 #include <linux/cpu.h>
 42 #include <linux/cpuset.h>
 43 #include <linux/cgroup.h>
 44 #include <linux/efi.h>
 45 #include <linux/tick.h>
 46 #include <linux/interrupt.h>
 47 #include <linux/taskstats_kern.h>
 48 #include <linux/delayacct.h>
 49 #include <linux/unistd.h>
 50 #include <linux/rmap.h>
 51 #include <linux/mempolicy.h>
 52 #include <linux/key.h>
 53 #include <linux/buffer_head.h>
 54 #include <linux/page_ext.h>
 55 #include <linux/debug_locks.h>
 56 #include <linux/debugobjects.h>
 57 #include <linux/lockdep.h>
 58 #include <linux/kmemleak.h>
 59 #include <linux/pid_namespace.h>
 60 #include <linux/device.h>
 61 #include <linux/kthread.h>
 62 #include <linux/sched.h>
 63 #include <linux/signal.h>
 64 #include <linux/idr.h>
 65 #include <linux/kgdb.h>
 66 #include <linux/ftrace.h>
 67 #include <linux/async.h>
 68 #include <linux/kmemcheck.h>
 69 #include <linux/sfi.h>
 70 #include <linux/shmem_fs.h>
 71 #include <linux/slab.h>
 72 #include <linux/perf_event.h>
 73 #include <linux/file.h>
 74 #include <linux/ptrace.h>
 75 #include <linux/blkdev.h>
 76 #include <linux/elevator.h>
 77 #include <linux/sched_clock.h>
 78 #include <linux/context_tracking.h>
 79 #include <linux/random.h>
 80 #include <linux/list.h>
 81 #include <linux/integrity.h>
 82 #include <linux/proc_ns.h>
 83 #include <linux/io.h>
 84 
 85 #include <asm/io.h>
 86 #include <asm/bugs.h>
 87 #include <asm/setup.h>
 88 #include <asm/sections.h>
 89 #include <asm/cacheflush.h>
 90 
 91 static int kernel_init(void *);
 92 
 93 extern void init_IRQ(void);
 94 extern void fork_init(void);
 95 extern void radix_tree_init(void);
 96 #ifndef CONFIG_DEBUG_RODATA
 97 static inline void mark_rodata_ro(void) { }
 98 #endif
 99 
100 /*
101  * Debug helper: via this flag we know that we are in 'early bootup code'
102  * where only the boot processor is running with IRQ disabled.  This means
103  * two things - IRQ must not be enabled before the flag is cleared and some
104  * operations which are not allowed with IRQ disabled are allowed while the
105  * flag is set.
106  */
107 bool early_boot_irqs_disabled __read_mostly;
108 
109 enum system_states system_state __read_mostly;
110 EXPORT_SYMBOL(system_state);
111 
112 /*
113  * Boot command-line arguments
114  */
115 #define MAX_INIT_ARGS CONFIG_INIT_ENV_ARG_LIMIT
116 #define MAX_INIT_ENVS CONFIG_INIT_ENV_ARG_LIMIT
117 
118 extern void time_init(void);
119 /* Default late time init is NULL. archs can override this later. */
120 void (*__initdata late_time_init)(void);
121 
122 /* Untouched command line saved by arch-specific code. */
123 char __initdata boot_command_line[COMMAND_LINE_SIZE];
124 /* Untouched saved command line (eg. for /proc) */
125 char *saved_command_line;
126 /* Command line for parameter parsing */
127 static char *static_command_line;
128 /* Command line for per-initcall parameter parsing */
129 static char *initcall_command_line;
130 
131 static char *execute_command;
132 static char *ramdisk_execute_command;
133 
134 /*
135  * Used to generate warnings if static_key manipulation functions are used
136  * before jump_label_init is called.
137  */
138 bool static_key_initialized __read_mostly;
139 EXPORT_SYMBOL_GPL(static_key_initialized);
140 
141 /*
142  * If set, this is an indication to the drivers that reset the underlying
143  * device before going ahead with the initialization otherwise driver might
144  * rely on the BIOS and skip the reset operation.
145  *
146  * This is useful if kernel is booting in an unreliable environment.
147  * For ex. kdump situation where previous kernel has crashed, BIOS has been
148  * skipped and devices will be in unknown state.
149  */
150 unsigned int reset_devices;
151 EXPORT_SYMBOL(reset_devices);
152 
153 static int __init set_reset_devices(char *str)
154 {
155         reset_devices = 1;
156         return 1;
157 }
158 
159 __setup("reset_devices", set_reset_devices);
160 
161 static const char *argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
162 const char *envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, };
163 static const char *panic_later, *panic_param;
164 
165 extern const struct obs_kernel_param __setup_start[], __setup_end[];
166 
167 static int __init obsolete_checksetup(char *line)
168 {
169         const struct obs_kernel_param *p;
170         int had_early_param = 0;
171 
172         p = __setup_start;
173         do {
174                 int n = strlen(p->str);
175                 if (parameqn(line, p->str, n)) {
176                         if (p->early) {
177                                 /* Already done in parse_early_param?
178                                  * (Needs exact match on param part).
179                                  * Keep iterating, as we can have early
180                                  * params and __setups of same names 8( */
181                                 if (line[n] == '\0' || line[n] == '=')
182                                         had_early_param = 1;
183                         } else if (!p->setup_func) {
184                                 pr_warn("Parameter %s is obsolete, ignored\n",
185                                         p->str);
186                                 return 1;
187                         } else if (p->setup_func(line + n))
188                                 return 1;
189                 }
190                 p++;
191         } while (p < __setup_end);
192 
193         return had_early_param;
194 }
195 
196 /*
197  * This should be approx 2 Bo*oMips to start (note initial shift), and will
198  * still work even if initially too large, it will just take slightly longer
199  */
200 unsigned long loops_per_jiffy = (1<<12);
201 EXPORT_SYMBOL(loops_per_jiffy);
202 
203 static int __init debug_kernel(char *str)
204 {
205         console_loglevel = CONSOLE_LOGLEVEL_DEBUG;
206         return 0;
207 }
208 
209 static int __init quiet_kernel(char *str)
210 {
211         console_loglevel = CONSOLE_LOGLEVEL_QUIET;
212         return 0;
213 }
214 
215 early_param("debug", debug_kernel);
216 early_param("quiet", quiet_kernel);
217 
218 static int __init loglevel(char *str)
219 {
220         int newlevel;
221 
222         /*
223          * Only update loglevel value when a correct setting was passed,
224          * to prevent blind crashes (when loglevel being set to 0) that
225          * are quite hard to debug
226          */
227         if (get_option(&str, &newlevel)) {
228                 console_loglevel = newlevel;
229                 return 0;
230         }
231 
232         return -EINVAL;
233 }
234 
235 early_param("loglevel", loglevel);
236 
237 /* Change NUL term back to "=", to make "param" the whole string. */
238 static int __init repair_env_string(char *param, char *val,
239                                     const char *unused, void *arg)
240 {
241         if (val) {
242                 /* param=val or param="val"? */
243                 if (val == param+strlen(param)+1)
244                         val[-1] = '=';
245                 else if (val == param+strlen(param)+2) {
246                         val[-2] = '=';
247                         memmove(val-1, val, strlen(val)+1);
248                         val--;
249                 } else
250                         BUG();
251         }
252         return 0;
253 }
254 
255 /* Anything after -- gets handed straight to init. */
256 static int __init set_init_arg(char *param, char *val,
257                                const char *unused, void *arg)
258 {
259         unsigned int i;
260 
261         if (panic_later)
262                 return 0;
263 
264         repair_env_string(param, val, unused, NULL);
265 
266         for (i = 0; argv_init[i]; i++) {
267                 if (i == MAX_INIT_ARGS) {
268                         panic_later = "init";
269                         panic_param = param;
270                         return 0;
271                 }
272         }
273         argv_init[i] = param;
274         return 0;
275 }
276 
277 /*
278  * Unknown boot options get handed to init, unless they look like
279  * unused parameters (modprobe will find them in /proc/cmdline).
280  */
281 static int __init unknown_bootoption(char *param, char *val,
282                                      const char *unused, void *arg)
283 {
284         repair_env_string(param, val, unused, NULL);
285 
286         /* Handle obsolete-style parameters */
287         if (obsolete_checksetup(param))
288                 return 0;
289 
290         /* Unused module parameter. */
291         if (strchr(param, '.') && (!val || strchr(param, '.') < val))
292                 return 0;
293 
294         if (panic_later)
295                 return 0;
296 
297         if (val) {
298                 /* Environment option */
299                 unsigned int i;
300                 for (i = 0; envp_init[i]; i++) {
301                         if (i == MAX_INIT_ENVS) {
302                                 panic_later = "env";
303                                 panic_param = param;
304                         }
305                         if (!strncmp(param, envp_init[i], val - param))
306                                 break;
307                 }
308                 envp_init[i] = param;
309         } else {
310                 /* Command line option */
311                 unsigned int i;
312                 for (i = 0; argv_init[i]; i++) {
313                         if (i == MAX_INIT_ARGS) {
314                                 panic_later = "init";
315                                 panic_param = param;
316                         }
317                 }
318                 argv_init[i] = param;
319         }
320         return 0;
321 }
322 
323 static int __init init_setup(char *str)
324 {
325         unsigned int i;
326 
327         execute_command = str;
328         /*
329          * In case LILO is going to boot us with default command line,
330          * it prepends "auto" before the whole cmdline which makes
331          * the shell think it should execute a script with such name.
332          * So we ignore all arguments entered _before_ init=... [MJ]
333          */
334         for (i = 1; i < MAX_INIT_ARGS; i++)
335                 argv_init[i] = NULL;
336         return 1;
337 }
338 __setup("init=", init_setup);
339 
340 static int __init rdinit_setup(char *str)
341 {
342         unsigned int i;
343 
344         ramdisk_execute_command = str;
345         /* See "auto" comment in init_setup */
346         for (i = 1; i < MAX_INIT_ARGS; i++)
347                 argv_init[i] = NULL;
348         return 1;
349 }
350 __setup("rdinit=", rdinit_setup);
351 
352 #ifndef CONFIG_SMP
353 static const unsigned int setup_max_cpus = NR_CPUS;
354 static inline void setup_nr_cpu_ids(void) { }
355 static inline void smp_prepare_cpus(unsigned int maxcpus) { }
356 #endif
357 
358 /*
359  * We need to store the untouched command line for future reference.
360  * We also need to store the touched command line since the parameter
361  * parsing is performed in place, and we should allow a component to
362  * store reference of name/value for future reference.
363  */
364 static void __init setup_command_line(char *command_line)
365 {
366         saved_command_line =
367                 memblock_virt_alloc(strlen(boot_command_line) + 1, 0);
368         initcall_command_line =
369                 memblock_virt_alloc(strlen(boot_command_line) + 1, 0);
370         static_command_line = memblock_virt_alloc(strlen(command_line) + 1, 0);
371         strcpy(saved_command_line, boot_command_line);
372         strcpy(static_command_line, command_line);
373 }
374 
375 /*
376  * We need to finalize in a non-__init function or else race conditions
377  * between the root thread and the init thread may cause start_kernel to
378  * be reaped by free_initmem before the root thread has proceeded to
379  * cpu_idle.
380  *
381  * gcc-3.4 accidentally inlines this function, so use noinline.
382  */
383 
384 static __initdata DECLARE_COMPLETION(kthreadd_done);
385 
386 static noinline void __init_refok rest_init(void)
387 {
388         int pid;
389 
390         rcu_scheduler_starting();
391         smpboot_thread_init();
392         /*
393          * We need to spawn init first so that it obtains pid 1, however
394          * the init task will end up wanting to create kthreads, which, if
395          * we schedule it before we create kthreadd, will OOPS.
396          */
397         kernel_thread(kernel_init, NULL, CLONE_FS);
398         numa_default_policy();
399         pid = kernel_thread(kthreadd, NULL, CLONE_FS | CLONE_FILES);
400         rcu_read_lock();
401         kthreadd_task = find_task_by_pid_ns(pid, &init_pid_ns);
402         rcu_read_unlock();
403         complete(&kthreadd_done);
404 
405         /*
406          * The boot idle thread must execute schedule()
407          * at least once to get things moving:
408          */
409         init_idle_bootup_task(current);
410         schedule_preempt_disabled();
411         /* Call into cpu_idle with preempt disabled */
412         cpu_startup_entry(CPUHP_ONLINE);
413 }
414 
415 /* Check for early params. */
416 static int __init do_early_param(char *param, char *val,
417                                  const char *unused, void *arg)
418 {
419         const struct obs_kernel_param *p;
420 
421         for (p = __setup_start; p < __setup_end; p++) {
422                 if ((p->early && parameq(param, p->str)) ||
423                     (strcmp(param, "console") == 0 &&
424                      strcmp(p->str, "earlycon") == 0)
425                 ) {
426                         if (p->setup_func(val) != 0)
427                                 pr_warn("Malformed early option '%s'\n", param);
428                 }
429         }
430         /* We accept everything at this stage. */
431         return 0;
432 }
433 
434 void __init parse_early_options(char *cmdline)
435 {
436         parse_args("early options", cmdline, NULL, 0, 0, 0, NULL,
437                    do_early_param);
438 }
439 
440 /* Arch code calls this early on, or if not, just before other parsing. */
441 void __init parse_early_param(void)
442 {
443         static int done __initdata;
444         static char tmp_cmdline[COMMAND_LINE_SIZE] __initdata;
445 
446         if (done)
447                 return;
448 
449         /* All fall through to do_early_param. */
450         strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);
451         parse_early_options(tmp_cmdline);
452         done = 1;
453 }
454 
455 /*
456  *      Activate the first processor.
457  */
458 
459 static void __init boot_cpu_init(void)
460 {
461         int cpu = smp_processor_id();
462         /* Mark the boot cpu "present", "online" etc for SMP and UP case */
463         set_cpu_online(cpu, true);
464         set_cpu_active(cpu, true);
465         set_cpu_present(cpu, true);
466         set_cpu_possible(cpu, true);
467 }
468 
469 void __init __weak smp_setup_processor_id(void)
470 {
471 }
472 
473 # if THREAD_SIZE >= PAGE_SIZE
474 void __init __weak thread_info_cache_init(void)
475 {
476 }
477 #endif
478 
479 /*
480  * Set up kernel memory allocators
481  */
482 static void __init mm_init(void)
483 {
484         /*
485          * page_ext requires contiguous pages,
486          * bigger than MAX_ORDER unless SPARSEMEM.
487          */
488         page_ext_init_flatmem();
489         mem_init();
490         kmem_cache_init();
491         percpu_init_late();
492         pgtable_init();
493         vmalloc_init();
494         ioremap_huge_init();
495 }
496 
497 asmlinkage __visible void __init start_kernel(void)
498 {
499         char *command_line;
500         char *after_dashes;
501 
502         /*
503          * Need to run as early as possible, to initialize the
504          * lockdep hash:
505          */
506         lockdep_init();
507         set_task_stack_end_magic(&init_task);
508         smp_setup_processor_id();
509         debug_objects_early_init();
510 
511         /*
512          * Set up the the initial canary ASAP:
513          */
514         boot_init_stack_canary();
515 
516         cgroup_init_early();
517 
518         local_irq_disable();
519         early_boot_irqs_disabled = true;
520 
521 /*
522  * Interrupts are still disabled. Do necessary setups, then
523  * enable them
524  */
525         boot_cpu_init();
526         page_address_init();
527         pr_notice("%s", linux_banner);
528         setup_arch(&command_line);
529         mm_init_cpumask(&init_mm);
530         setup_command_line(command_line);
531         setup_nr_cpu_ids();
532         setup_per_cpu_areas();
533         smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */
534 
535         build_all_zonelists(NULL, NULL);
536         page_alloc_init();
537 
538         pr_notice("Kernel command line: %s\n", boot_command_line);
539         parse_early_param();
540         after_dashes = parse_args("Booting kernel",
541                                   static_command_line, __start___param,
542                                   __stop___param - __start___param,
543                                   -1, -1, NULL, &unknown_bootoption);
544         if (!IS_ERR_OR_NULL(after_dashes))
545                 parse_args("Setting init args", after_dashes, NULL, 0, -1, -1,
546                            NULL, set_init_arg);
547 
548         jump_label_init();
549 
550         /*
551          * These use large bootmem allocations and must precede
552          * kmem_cache_init()
553          */
554         setup_log_buf(0);
555         pidhash_init();
556         vfs_caches_init_early();
557         sort_main_extable();
558         trap_init();
559         mm_init();
560 
561         /*
562          * Set up the scheduler prior starting any interrupts (such as the
563          * timer interrupt). Full topology setup happens at smp_init()
564          * time - but meanwhile we still have a functioning scheduler.
565          */
566         sched_init();
567         /*
568          * Disable preemption - early bootup scheduling is extremely
569          * fragile until we cpu_idle() for the first time.
570          */
571         preempt_disable();
572         if (WARN(!irqs_disabled(),
573                  "Interrupts were enabled *very* early, fixing it\n"))
574                 local_irq_disable();
575         idr_init_cache();
576         rcu_init();
577 
578         /* trace_printk() and trace points may be used after this */
579         trace_init();
580 
581         context_tracking_init();
582         radix_tree_init();
583         /* init some links before init_ISA_irqs() */
584         early_irq_init();
585         init_IRQ();
586         tick_init();
587         rcu_init_nohz();
588         init_timers();
589         hrtimers_init();
590         softirq_init();
591         timekeeping_init();
592         time_init();
593         sched_clock_postinit();
594         perf_event_init();
595         profile_init();
596         call_function_init();
597         WARN(!irqs_disabled(), "Interrupts were enabled early\n");
598         early_boot_irqs_disabled = false;
599         local_irq_enable();
600 
601         kmem_cache_init_late();
602 
603         /*
604          * HACK ALERT! This is early. We're enabling the console before
605          * we've done PCI setups etc, and console_init() must be aware of
606          * this. But we do want output early, in case something goes wrong.
607          */
608         console_init();
609         if (panic_later)
610                 panic("Too many boot %s vars at `%s'", panic_later,
611                       panic_param);
612 
613         lockdep_info();
614 
615         /*
616          * Need to run this when irqs are enabled, because it wants
617          * to self-test [hard/soft]-irqs on/off lock inversion bugs
618          * too:
619          */
620         locking_selftest();
621 
622 #ifdef CONFIG_BLK_DEV_INITRD
623         if (initrd_start && !initrd_below_start_ok &&
624             page_to_pfn(virt_to_page((void *)initrd_start)) < min_low_pfn) {
625                 pr_crit("initrd overwritten (0x%08lx < 0x%08lx) - disabling it.\n",
626                     page_to_pfn(virt_to_page((void *)initrd_start)),
627                     min_low_pfn);
628                 initrd_start = 0;
629         }
630 #endif
631         page_ext_init();
632         debug_objects_mem_init();
633         kmemleak_init();
634         setup_per_cpu_pageset();
635         numa_policy_init();
636         if (late_time_init)
637                 late_time_init();
638         sched_clock_init();
639         calibrate_delay();
640         pidmap_init();
641         anon_vma_init();
642         acpi_early_init();
643 #ifdef CONFIG_X86
644         if (efi_enabled(EFI_RUNTIME_SERVICES))
645                 efi_enter_virtual_mode();
646 #endif
647 #ifdef CONFIG_X86_ESPFIX64
648         /* Should be run before the first non-init thread is created */
649         init_espfix_bsp();
650 #endif
651         thread_info_cache_init();
652         cred_init();
653         fork_init();
654         proc_caches_init();
655         buffer_init();
656         key_init();
657         security_init();
658         dbg_late_init();
659         vfs_caches_init();
660         signals_init();
661         /* rootfs populating might need page-writeback */
662         page_writeback_init();
663         proc_root_init();
664         nsfs_init();
665         cpuset_init();
666         cgroup_init();
667         taskstats_init_early();
668         delayacct_init();
669 
670         check_bugs();
671 
672         acpi_subsystem_init();
673         sfi_init_late();
674 
675         if (efi_enabled(EFI_RUNTIME_SERVICES)) {
676                 efi_late_init();
677                 efi_free_boot_services();
678         }
679 
680         ftrace_init();
681 
682         /* Do the rest non-__init'ed, we're now alive */
683         rest_init();
684 }
685 
686 /* Call all constructor functions linked into the kernel. */
687 static void __init do_ctors(void)
688 {
689 #ifdef CONFIG_CONSTRUCTORS
690         ctor_fn_t *fn = (ctor_fn_t *) __ctors_start;
691 
692         for (; fn < (ctor_fn_t *) __ctors_end; fn++)
693                 (*fn)();
694 #endif
695 }
696 
697 bool initcall_debug;
698 core_param(initcall_debug, initcall_debug, bool, 0644);
699 
700 #ifdef CONFIG_KALLSYMS
701 struct blacklist_entry {
702         struct list_head next;
703         char *buf;
704 };
705 
706 static __initdata_or_module LIST_HEAD(blacklisted_initcalls);
707 
708 static int __init initcall_blacklist(char *str)
709 {
710         char *str_entry;
711         struct blacklist_entry *entry;
712 
713         /* str argument is a comma-separated list of functions */
714         do {
715                 str_entry = strsep(&str, ",");
716                 if (str_entry) {
717                         pr_debug("blacklisting initcall %s\n", str_entry);
718                         entry = alloc_bootmem(sizeof(*entry));
719                         entry->buf = alloc_bootmem(strlen(str_entry) + 1);
720                         strcpy(entry->buf, str_entry);
721                         list_add(&entry->next, &blacklisted_initcalls);
722                 }
723         } while (str_entry);
724 
725         return 0;
726 }
727 
728 static bool __init_or_module initcall_blacklisted(initcall_t fn)
729 {
730         struct list_head *tmp;
731         struct blacklist_entry *entry;
732         char *fn_name;
733 
734         fn_name = kasprintf(GFP_KERNEL, "%pf", fn);
735         if (!fn_name)
736                 return false;
737 
738         list_for_each(tmp, &blacklisted_initcalls) {
739                 entry = list_entry(tmp, struct blacklist_entry, next);
740                 if (!strcmp(fn_name, entry->buf)) {
741                         pr_debug("initcall %s blacklisted\n", fn_name);
742                         kfree(fn_name);
743                         return true;
744                 }
745         }
746 
747         kfree(fn_name);
748         return false;
749 }
750 #else
751 static int __init initcall_blacklist(char *str)
752 {
753         pr_warn("initcall_blacklist requires CONFIG_KALLSYMS\n");
754         return 0;
755 }
756 
757 static bool __init_or_module initcall_blacklisted(initcall_t fn)
758 {
759         return false;
760 }
761 #endif
762 __setup("initcall_blacklist=", initcall_blacklist);
763 
764 static int __init_or_module do_one_initcall_debug(initcall_t fn)
765 {
766         ktime_t calltime, delta, rettime;
767         unsigned long long duration;
768         int ret;
769 
770         printk(KERN_DEBUG "calling  %pF @ %i\n", fn, task_pid_nr(current));
771         calltime = ktime_get();
772         ret = fn();
773         rettime = ktime_get();
774         delta = ktime_sub(rettime, calltime);
775         duration = (unsigned long long) ktime_to_ns(delta) >> 10;
776         printk(KERN_DEBUG "initcall %pF returned %d after %lld usecs\n",
777                  fn, ret, duration);
778 
779         return ret;
780 }
781 
782 int __init_or_module do_one_initcall(initcall_t fn)
783 {
784         int count = preempt_count();
785         int ret;
786         char msgbuf[64];
787 
788         if (initcall_blacklisted(fn))
789                 return -EPERM;
790 
791         if (initcall_debug)
792                 ret = do_one_initcall_debug(fn);
793         else
794                 ret = fn();
795 
796         msgbuf[0] = 0;
797 
798         if (preempt_count() != count) {
799                 sprintf(msgbuf, "preemption imbalance ");
800                 preempt_count_set(count);
801         }
802         if (irqs_disabled()) {
803                 strlcat(msgbuf, "disabled interrupts ", sizeof(msgbuf));
804                 local_irq_enable();
805         }
806         WARN(msgbuf[0], "initcall %pF returned with %s\n", fn, msgbuf);
807 
808         return ret;
809 }
810 
811 
812 extern initcall_t __initcall_start[];
813 extern initcall_t __initcall0_start[];
814 extern initcall_t __initcall1_start[];
815 extern initcall_t __initcall2_start[];
816 extern initcall_t __initcall3_start[];
817 extern initcall_t __initcall4_start[];
818 extern initcall_t __initcall5_start[];
819 extern initcall_t __initcall6_start[];
820 extern initcall_t __initcall7_start[];
821 extern initcall_t __initcall_end[];
822 
823 static initcall_t *initcall_levels[] __initdata = {
824         __initcall0_start,
825         __initcall1_start,
826         __initcall2_start,
827         __initcall3_start,
828         __initcall4_start,
829         __initcall5_start,
830         __initcall6_start,
831         __initcall7_start,
832         __initcall_end,
833 };
834 
835 /* Keep these in sync with initcalls in include/linux/init.h */
836 static char *initcall_level_names[] __initdata = {
837         "early",
838         "core",
839         "postcore",
840         "arch",
841         "subsys",
842         "fs",
843         "device",
844         "late",
845 };
846 
847 static void __init do_initcall_level(int level)
848 {
849         initcall_t *fn;
850 
851         strcpy(initcall_command_line, saved_command_line);
852         parse_args(initcall_level_names[level],
853                    initcall_command_line, __start___param,
854                    __stop___param - __start___param,
855                    level, level,
856                    NULL, &repair_env_string);
857 
858         for (fn = initcall_levels[level]; fn < initcall_levels[level+1]; fn++)
859                 do_one_initcall(*fn);
860 }
861 
862 static void __init do_initcalls(void)
863 {
864         int level;
865 
866         for (level = 0; level < ARRAY_SIZE(initcall_levels) - 1; level++)
867                 do_initcall_level(level);
868 }
869 
870 /*
871  * Ok, the machine is now initialized. None of the devices
872  * have been touched yet, but the CPU subsystem is up and
873  * running, and memory and process management works.
874  *
875  * Now we can finally start doing some real work..
876  */
877 static void __init do_basic_setup(void)
878 {
879         cpuset_init_smp();
880         usermodehelper_init();
881         shmem_init();
882         driver_init();
883         init_irq_proc();
884         do_ctors();
885         usermodehelper_enable();
886         do_initcalls();
887         random_int_secret_init();
888 }
889 
890 static void __init do_pre_smp_initcalls(void)
891 {
892         initcall_t *fn;
893 
894         for (fn = __initcall_start; fn < __initcall0_start; fn++)
895                 do_one_initcall(*fn);
896 }
897 
898 /*
899  * This function requests modules which should be loaded by default and is
900  * called twice right after initrd is mounted and right before init is
901  * exec'd.  If such modules are on either initrd or rootfs, they will be
902  * loaded before control is passed to userland.
903  */
904 void __init load_default_modules(void)
905 {
906         load_default_elevator_module();
907 }
908 
909 static int run_init_process(const char *init_filename)
910 {
911         argv_init[0] = init_filename;
912         return do_execve(getname_kernel(init_filename),
913                 (const char __user *const __user *)argv_init,
914                 (const char __user *const __user *)envp_init);
915 }
916 
917 static int try_to_run_init_process(const char *init_filename)
918 {
919         int ret;
920 
921         ret = run_init_process(init_filename);
922 
923         if (ret && ret != -ENOENT) {
924                 pr_err("Starting init: %s exists but couldn't execute it (error %d)\n",
925                        init_filename, ret);
926         }
927 
928         return ret;
929 }
930 
931 static noinline void __init kernel_init_freeable(void);
932 
933 static int __ref kernel_init(void *unused)
934 {
935         int ret;
936 
937         kernel_init_freeable();
938         /* need to finish all async __init code before freeing the memory */
939         async_synchronize_full();
940         free_initmem();
941         mark_rodata_ro();
942         system_state = SYSTEM_RUNNING;
943         numa_default_policy();
944 
945         flush_delayed_fput();
946 
947         if (ramdisk_execute_command) {
948                 ret = run_init_process(ramdisk_execute_command);
949                 if (!ret)
950                         return 0;
951                 pr_err("Failed to execute %s (error %d)\n",
952                        ramdisk_execute_command, ret);
953         }
954 
955         /*
956          * We try each of these until one succeeds.
957          *
958          * The Bourne shell can be used instead of init if we are
959          * trying to recover a really broken machine.
960          */
961         if (execute_command) {
962                 ret = run_init_process(execute_command);
963                 if (!ret)
964                         return 0;
965                 panic("Requested init %s failed (error %d).",
966                       execute_command, ret);
967         }
968         if (!try_to_run_init_process("/sbin/init") ||
969             !try_to_run_init_process("/etc/init") ||
970             !try_to_run_init_process("/bin/init") ||
971             !try_to_run_init_process("/bin/sh"))
972                 return 0;
973 
974         panic("No working init found.  Try passing init= option to kernel. "
975               "See Linux Documentation/init.txt for guidance.");
976 }
977 
978 static noinline void __init kernel_init_freeable(void)
979 {
980         /*
981          * Wait until kthreadd is all set-up.
982          */
983         wait_for_completion(&kthreadd_done);
984 
985         /* Now the scheduler is fully set up and can do blocking allocations */
986         gfp_allowed_mask = __GFP_BITS_MASK;
987 
988         /*
989          * init can allocate pages on any node
990          */
991         set_mems_allowed(node_states[N_MEMORY]);
992         /*
993          * init can run on any cpu.
994          */
995         set_cpus_allowed_ptr(current, cpu_all_mask);
996 
997         cad_pid = task_pid(current);
998 
999         smp_prepare_cpus(setup_max_cpus);
1000 
1001         do_pre_smp_initcalls();
1002         lockup_detector_init();
1003 
1004         smp_init();
1005         sched_init_smp();
1006 
1007         page_alloc_init_late();
1008 
1009         do_basic_setup();
1010 
1011         /* Open the /dev/console on the rootfs, this should never fail */
1012         if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0)
1013                 pr_err("Warning: unable to open an initial console.\n");
1014 
1015         (void) sys_dup(0);
1016         (void) sys_dup(0);
1017         /*
1018          * check if there is an early userspace init.  If yes, let it do all
1019          * the work
1020          */
1021 
1022         if (!ramdisk_execute_command)
1023                 ramdisk_execute_command = "/init";
1024 
1025         if (sys_access((const char __user *) ramdisk_execute_command, 0) != 0) {
1026                 ramdisk_execute_command = NULL;
1027                 prepare_namespace();
1028         }
1029 
1030         /*
1031          * Ok, we have completed the initial bootup, and
1032          * we're essentially up and running. Get rid of the
1033          * initmem segments and start the user-mode stuff..
1034          *
1035          * rootfs is available now, try loading the public keys
1036          * and default modules
1037          */
1038 
1039         integrity_load_keys();
1040         load_default_modules();
1041 }
1042 

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