Version:  2.0.40 2.2.26 2.4.37 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16

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_cgroup.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 
 82 #include <asm/io.h>
 83 #include <asm/bugs.h>
 84 #include <asm/setup.h>
 85 #include <asm/sections.h>
 86 #include <asm/cacheflush.h>
 87 
 88 #ifdef CONFIG_X86_LOCAL_APIC
 89 #include <asm/smp.h>
 90 #endif
 91 
 92 static int kernel_init(void *);
 93 
 94 extern void init_IRQ(void);
 95 extern void fork_init(unsigned long);
 96 extern void radix_tree_init(void);
 97 #ifndef CONFIG_DEBUG_RODATA
 98 static inline void mark_rodata_ro(void) { }
 99 #endif
100 
101 /*
102  * Debug helper: via this flag we know that we are in 'early bootup code'
103  * where only the boot processor is running with IRQ disabled.  This means
104  * two things - IRQ must not be enabled before the flag is cleared and some
105  * operations which are not allowed with IRQ disabled are allowed while the
106  * flag is set.
107  */
108 bool early_boot_irqs_disabled __read_mostly;
109 
110 enum system_states system_state __read_mostly;
111 EXPORT_SYMBOL(system_state);
112 
113 /*
114  * Boot command-line arguments
115  */
116 #define MAX_INIT_ARGS CONFIG_INIT_ENV_ARG_LIMIT
117 #define MAX_INIT_ENVS CONFIG_INIT_ENV_ARG_LIMIT
118 
119 extern void time_init(void);
120 /* Default late time init is NULL. archs can override this later. */
121 void (*__initdata late_time_init)(void);
122 
123 /* Untouched command line saved by arch-specific code. */
124 char __initdata boot_command_line[COMMAND_LINE_SIZE];
125 /* Untouched saved command line (eg. for /proc) */
126 char *saved_command_line;
127 /* Command line for parameter parsing */
128 static char *static_command_line;
129 /* Command line for per-initcall parameter parsing */
130 static char *initcall_command_line;
131 
132 static char *execute_command;
133 static char *ramdisk_execute_command;
134 
135 /*
136  * Used to generate warnings if static_key manipulation functions are used
137  * before jump_label_init is called.
138  */
139 bool static_key_initialized __read_mostly = false;
140 EXPORT_SYMBOL_GPL(static_key_initialized);
141 
142 /*
143  * If set, this is an indication to the drivers that reset the underlying
144  * device before going ahead with the initialization otherwise driver might
145  * rely on the BIOS and skip the reset operation.
146  *
147  * This is useful if kernel is booting in an unreliable environment.
148  * For ex. kdump situaiton where previous kernel has crashed, BIOS has been
149  * skipped and devices will be in unknown state.
150  */
151 unsigned int reset_devices;
152 EXPORT_SYMBOL(reset_devices);
153 
154 static int __init set_reset_devices(char *str)
155 {
156         reset_devices = 1;
157         return 1;
158 }
159 
160 __setup("reset_devices", set_reset_devices);
161 
162 static const char * argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
163 const char * envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, };
164 static const char *panic_later, *panic_param;
165 
166 extern const struct obs_kernel_param __setup_start[], __setup_end[];
167 
168 static int __init obsolete_checksetup(char *line)
169 {
170         const struct obs_kernel_param *p;
171         int had_early_param = 0;
172 
173         p = __setup_start;
174         do {
175                 int n = strlen(p->str);
176                 if (parameqn(line, p->str, n)) {
177                         if (p->early) {
178                                 /* Already done in parse_early_param?
179                                  * (Needs exact match on param part).
180                                  * Keep iterating, as we can have early
181                                  * params and __setups of same names 8( */
182                                 if (line[n] == '\0' || line[n] == '=')
183                                         had_early_param = 1;
184                         } else if (!p->setup_func) {
185                                 pr_warn("Parameter %s is obsolete, ignored\n",
186                                         p->str);
187                                 return 1;
188                         } else if (p->setup_func(line + n))
189                                 return 1;
190                 }
191                 p++;
192         } while (p < __setup_end);
193 
194         return had_early_param;
195 }
196 
197 /*
198  * This should be approx 2 Bo*oMips to start (note initial shift), and will
199  * still work even if initially too large, it will just take slightly longer
200  */
201 unsigned long loops_per_jiffy = (1<<12);
202 
203 EXPORT_SYMBOL(loops_per_jiffy);
204 
205 static int __init debug_kernel(char *str)
206 {
207         console_loglevel = CONSOLE_LOGLEVEL_DEBUG;
208         return 0;
209 }
210 
211 static int __init quiet_kernel(char *str)
212 {
213         console_loglevel = CONSOLE_LOGLEVEL_QUIET;
214         return 0;
215 }
216 
217 early_param("debug", debug_kernel);
218 early_param("quiet", quiet_kernel);
219 
220 static int __init loglevel(char *str)
221 {
222         int newlevel;
223 
224         /*
225          * Only update loglevel value when a correct setting was passed,
226          * to prevent blind crashes (when loglevel being set to 0) that
227          * are quite hard to debug
228          */
229         if (get_option(&str, &newlevel)) {
230                 console_loglevel = newlevel;
231                 return 0;
232         }
233 
234         return -EINVAL;
235 }
236 
237 early_param("loglevel", loglevel);
238 
239 /* Change NUL term back to "=", to make "param" the whole string. */
240 static int __init repair_env_string(char *param, char *val, const char *unused)
241 {
242         if (val) {
243                 /* param=val or param="val"? */
244                 if (val == param+strlen(param)+1)
245                         val[-1] = '=';
246                 else if (val == param+strlen(param)+2) {
247                         val[-2] = '=';
248                         memmove(val-1, val, strlen(val)+1);
249                         val--;
250                 } else
251                         BUG();
252         }
253         return 0;
254 }
255 
256 /* Anything after -- gets handed straight to init. */
257 static int __init set_init_arg(char *param, char *val, const char *unused)
258 {
259         unsigned int i;
260 
261         if (panic_later)
262                 return 0;
263 
264         repair_env_string(param, val, unused);
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, const char *unused)
282 {
283         repair_env_string(param, val, unused);
284 
285         /* Handle obsolete-style parameters */
286         if (obsolete_checksetup(param))
287                 return 0;
288 
289         /* Unused module parameter. */
290         if (strchr(param, '.') && (!val || strchr(param, '.') < val))
291                 return 0;
292 
293         if (panic_later)
294                 return 0;
295 
296         if (val) {
297                 /* Environment option */
298                 unsigned int i;
299                 for (i = 0; envp_init[i]; i++) {
300                         if (i == MAX_INIT_ENVS) {
301                                 panic_later = "env";
302                                 panic_param = param;
303                         }
304                         if (!strncmp(param, envp_init[i], val - param))
305                                 break;
306                 }
307                 envp_init[i] = param;
308         } else {
309                 /* Command line option */
310                 unsigned int i;
311                 for (i = 0; argv_init[i]; i++) {
312                         if (i == MAX_INIT_ARGS) {
313                                 panic_later = "init";
314                                 panic_param = param;
315                         }
316                 }
317                 argv_init[i] = param;
318         }
319         return 0;
320 }
321 
322 static int __init init_setup(char *str)
323 {
324         unsigned int i;
325 
326         execute_command = str;
327         /*
328          * In case LILO is going to boot us with default command line,
329          * it prepends "auto" before the whole cmdline which makes
330          * the shell think it should execute a script with such name.
331          * So we ignore all arguments entered _before_ init=... [MJ]
332          */
333         for (i = 1; i < MAX_INIT_ARGS; i++)
334                 argv_init[i] = NULL;
335         return 1;
336 }
337 __setup("init=", init_setup);
338 
339 static int __init rdinit_setup(char *str)
340 {
341         unsigned int i;
342 
343         ramdisk_execute_command = str;
344         /* See "auto" comment in init_setup */
345         for (i = 1; i < MAX_INIT_ARGS; i++)
346                 argv_init[i] = NULL;
347         return 1;
348 }
349 __setup("rdinit=", rdinit_setup);
350 
351 #ifndef CONFIG_SMP
352 static const unsigned int setup_max_cpus = NR_CPUS;
353 #ifdef CONFIG_X86_LOCAL_APIC
354 static void __init smp_init(void)
355 {
356         APIC_init_uniprocessor();
357 }
358 #else
359 #define smp_init()      do { } while (0)
360 #endif
361 
362 static inline void setup_nr_cpu_ids(void) { }
363 static inline void smp_prepare_cpus(unsigned int maxcpus) { }
364 #endif
365 
366 /*
367  * We need to store the untouched command line for future reference.
368  * We also need to store the touched command line since the parameter
369  * parsing is performed in place, and we should allow a component to
370  * store reference of name/value for future reference.
371  */
372 static void __init setup_command_line(char *command_line)
373 {
374         saved_command_line =
375                 memblock_virt_alloc(strlen(boot_command_line) + 1, 0);
376         initcall_command_line =
377                 memblock_virt_alloc(strlen(boot_command_line) + 1, 0);
378         static_command_line = memblock_virt_alloc(strlen(command_line) + 1, 0);
379         strcpy (saved_command_line, boot_command_line);
380         strcpy (static_command_line, command_line);
381 }
382 
383 /*
384  * We need to finalize in a non-__init function or else race conditions
385  * between the root thread and the init thread may cause start_kernel to
386  * be reaped by free_initmem before the root thread has proceeded to
387  * cpu_idle.
388  *
389  * gcc-3.4 accidentally inlines this function, so use noinline.
390  */
391 
392 static __initdata DECLARE_COMPLETION(kthreadd_done);
393 
394 static noinline void __init_refok rest_init(void)
395 {
396         int pid;
397 
398         rcu_scheduler_starting();
399         /*
400          * We need to spawn init first so that it obtains pid 1, however
401          * the init task will end up wanting to create kthreads, which, if
402          * we schedule it before we create kthreadd, will OOPS.
403          */
404         kernel_thread(kernel_init, NULL, CLONE_FS);
405         numa_default_policy();
406         pid = kernel_thread(kthreadd, NULL, CLONE_FS | CLONE_FILES);
407         rcu_read_lock();
408         kthreadd_task = find_task_by_pid_ns(pid, &init_pid_ns);
409         rcu_read_unlock();
410         complete(&kthreadd_done);
411 
412         /*
413          * The boot idle thread must execute schedule()
414          * at least once to get things moving:
415          */
416         init_idle_bootup_task(current);
417         schedule_preempt_disabled();
418         /* Call into cpu_idle with preempt disabled */
419         cpu_startup_entry(CPUHP_ONLINE);
420 }
421 
422 /* Check for early params. */
423 static int __init do_early_param(char *param, char *val, const char *unused)
424 {
425         const struct obs_kernel_param *p;
426 
427         for (p = __setup_start; p < __setup_end; p++) {
428                 if ((p->early && parameq(param, p->str)) ||
429                     (strcmp(param, "console") == 0 &&
430                      strcmp(p->str, "earlycon") == 0)
431                 ) {
432                         if (p->setup_func(val) != 0)
433                                 pr_warn("Malformed early option '%s'\n", param);
434                 }
435         }
436         /* We accept everything at this stage. */
437         return 0;
438 }
439 
440 void __init parse_early_options(char *cmdline)
441 {
442         parse_args("early options", cmdline, NULL, 0, 0, 0, do_early_param);
443 }
444 
445 /* Arch code calls this early on, or if not, just before other parsing. */
446 void __init parse_early_param(void)
447 {
448         static __initdata int done = 0;
449         static __initdata char tmp_cmdline[COMMAND_LINE_SIZE];
450 
451         if (done)
452                 return;
453 
454         /* All fall through to do_early_param. */
455         strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);
456         parse_early_options(tmp_cmdline);
457         done = 1;
458 }
459 
460 /*
461  *      Activate the first processor.
462  */
463 
464 static void __init boot_cpu_init(void)
465 {
466         int cpu = smp_processor_id();
467         /* Mark the boot cpu "present", "online" etc for SMP and UP case */
468         set_cpu_online(cpu, true);
469         set_cpu_active(cpu, true);
470         set_cpu_present(cpu, true);
471         set_cpu_possible(cpu, true);
472 }
473 
474 void __init __weak smp_setup_processor_id(void)
475 {
476 }
477 
478 # if THREAD_SIZE >= PAGE_SIZE
479 void __init __weak thread_info_cache_init(void)
480 {
481 }
482 #endif
483 
484 /*
485  * Set up kernel memory allocators
486  */
487 static void __init mm_init(void)
488 {
489         /*
490          * page_cgroup requires contiguous pages,
491          * bigger than MAX_ORDER unless SPARSEMEM.
492          */
493         page_cgroup_init_flatmem();
494         mem_init();
495         kmem_cache_init();
496         percpu_init_late();
497         pgtable_init();
498         vmalloc_init();
499 }
500 
501 asmlinkage __visible void __init start_kernel(void)
502 {
503         char * command_line, *after_dashes;
504         extern const struct kernel_param __start___param[], __stop___param[];
505 
506         /*
507          * Need to run as early as possible, to initialize the
508          * lockdep hash:
509          */
510         lockdep_init();
511         smp_setup_processor_id();
512         debug_objects_early_init();
513 
514         /*
515          * Set up the the initial canary ASAP:
516          */
517         boot_init_stack_canary();
518 
519         cgroup_init_early();
520 
521         local_irq_disable();
522         early_boot_irqs_disabled = true;
523 
524 /*
525  * Interrupts are still disabled. Do necessary setups, then
526  * enable them
527  */
528         boot_cpu_init();
529         page_address_init();
530         pr_notice("%s", linux_banner);
531         setup_arch(&command_line);
532         mm_init_cpumask(&init_mm);
533         setup_command_line(command_line);
534         setup_nr_cpu_ids();
535         setup_per_cpu_areas();
536         smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */
537 
538         build_all_zonelists(NULL, NULL);
539         page_alloc_init();
540 
541         pr_notice("Kernel command line: %s\n", boot_command_line);
542         parse_early_param();
543         after_dashes = parse_args("Booting kernel",
544                                   static_command_line, __start___param,
545                                   __stop___param - __start___param,
546                                   -1, -1, &unknown_bootoption);
547         if (after_dashes)
548                 parse_args("Setting init args", after_dashes, NULL, 0, -1, -1,
549                            set_init_arg);
550 
551         jump_label_init();
552 
553         /*
554          * These use large bootmem allocations and must precede
555          * kmem_cache_init()
556          */
557         setup_log_buf(0);
558         pidhash_init();
559         vfs_caches_init_early();
560         sort_main_extable();
561         trap_init();
562         mm_init();
563 
564         /*
565          * Set up the scheduler prior starting any interrupts (such as the
566          * timer interrupt). Full topology setup happens at smp_init()
567          * time - but meanwhile we still have a functioning scheduler.
568          */
569         sched_init();
570         /*
571          * Disable preemption - early bootup scheduling is extremely
572          * fragile until we cpu_idle() for the first time.
573          */
574         preempt_disable();
575         if (WARN(!irqs_disabled(), "Interrupts were enabled *very* early, fixing it\n"))
576                 local_irq_disable();
577         idr_init_cache();
578         rcu_init();
579         tick_nohz_init();
580         context_tracking_init();
581         radix_tree_init();
582         /* init some links before init_ISA_irqs() */
583         early_irq_init();
584         init_IRQ();
585         tick_init();
586         init_timers();
587         hrtimers_init();
588         softirq_init();
589         timekeeping_init();
590         time_init();
591         sched_clock_postinit();
592         perf_event_init();
593         profile_init();
594         call_function_init();
595         WARN(!irqs_disabled(), "Interrupts were enabled early\n");
596         early_boot_irqs_disabled = false;
597         local_irq_enable();
598 
599         kmem_cache_init_late();
600 
601         /*
602          * HACK ALERT! This is early. We're enabling the console before
603          * we've done PCI setups etc, and console_init() must be aware of
604          * this. But we do want output early, in case something goes wrong.
605          */
606         console_init();
607         if (panic_later)
608                 panic("Too many boot %s vars at `%s'", panic_later,
609                       panic_param);
610 
611         lockdep_info();
612 
613         /*
614          * Need to run this when irqs are enabled, because it wants
615          * to self-test [hard/soft]-irqs on/off lock inversion bugs
616          * too:
617          */
618         locking_selftest();
619 
620 #ifdef CONFIG_BLK_DEV_INITRD
621         if (initrd_start && !initrd_below_start_ok &&
622             page_to_pfn(virt_to_page((void *)initrd_start)) < min_low_pfn) {
623                 pr_crit("initrd overwritten (0x%08lx < 0x%08lx) - disabling it.\n",
624                     page_to_pfn(virt_to_page((void *)initrd_start)),
625                     min_low_pfn);
626                 initrd_start = 0;
627         }
628 #endif
629         page_cgroup_init();
630         debug_objects_mem_init();
631         kmemleak_init();
632         setup_per_cpu_pageset();
633         numa_policy_init();
634         if (late_time_init)
635                 late_time_init();
636         sched_clock_init();
637         calibrate_delay();
638         pidmap_init();
639         anon_vma_init();
640         acpi_early_init();
641 #ifdef CONFIG_X86
642         if (efi_enabled(EFI_RUNTIME_SERVICES))
643                 efi_enter_virtual_mode();
644 #endif
645 #ifdef CONFIG_X86_ESPFIX64
646         /* Should be run before the first non-init thread is created */
647         init_espfix_bsp();
648 #endif
649         thread_info_cache_init();
650         cred_init();
651         fork_init(totalram_pages);
652         proc_caches_init();
653         buffer_init();
654         key_init();
655         security_init();
656         dbg_late_init();
657         vfs_caches_init(totalram_pages);
658         signals_init();
659         /* rootfs populating might need page-writeback */
660         page_writeback_init();
661         proc_root_init();
662         cgroup_init();
663         cpuset_init();
664         taskstats_init_early();
665         delayacct_init();
666 
667         check_bugs();
668 
669         sfi_init_late();
670 
671         if (efi_enabled(EFI_RUNTIME_SERVICES)) {
672                 efi_late_init();
673                 efi_free_boot_services();
674         }
675 
676         ftrace_init();
677 
678         /* Do the rest non-__init'ed, we're now alive */
679         rest_init();
680 }
681 
682 /* Call all constructor functions linked into the kernel. */
683 static void __init do_ctors(void)
684 {
685 #ifdef CONFIG_CONSTRUCTORS
686         ctor_fn_t *fn = (ctor_fn_t *) __ctors_start;
687 
688         for (; fn < (ctor_fn_t *) __ctors_end; fn++)
689                 (*fn)();
690 #endif
691 }
692 
693 bool initcall_debug;
694 core_param(initcall_debug, initcall_debug, bool, 0644);
695 
696 #ifdef CONFIG_KALLSYMS
697 struct blacklist_entry {
698         struct list_head next;
699         char *buf;
700 };
701 
702 static __initdata_or_module LIST_HEAD(blacklisted_initcalls);
703 
704 static int __init initcall_blacklist(char *str)
705 {
706         char *str_entry;
707         struct blacklist_entry *entry;
708 
709         /* str argument is a comma-separated list of functions */
710         do {
711                 str_entry = strsep(&str, ",");
712                 if (str_entry) {
713                         pr_debug("blacklisting initcall %s\n", str_entry);
714                         entry = alloc_bootmem(sizeof(*entry));
715                         entry->buf = alloc_bootmem(strlen(str_entry) + 1);
716                         strcpy(entry->buf, str_entry);
717                         list_add(&entry->next, &blacklisted_initcalls);
718                 }
719         } while (str_entry);
720 
721         return 0;
722 }
723 
724 static bool __init_or_module initcall_blacklisted(initcall_t fn)
725 {
726         struct list_head *tmp;
727         struct blacklist_entry *entry;
728         char *fn_name;
729 
730         fn_name = kasprintf(GFP_KERNEL, "%pf", fn);
731         if (!fn_name)
732                 return false;
733 
734         list_for_each(tmp, &blacklisted_initcalls) {
735                 entry = list_entry(tmp, struct blacklist_entry, next);
736                 if (!strcmp(fn_name, entry->buf)) {
737                         pr_debug("initcall %s blacklisted\n", fn_name);
738                         kfree(fn_name);
739                         return true;
740                 }
741         }
742 
743         kfree(fn_name);
744         return false;
745 }
746 #else
747 static int __init initcall_blacklist(char *str)
748 {
749         pr_warn("initcall_blacklist requires CONFIG_KALLSYMS\n");
750         return 0;
751 }
752 
753 static bool __init_or_module initcall_blacklisted(initcall_t fn)
754 {
755         return false;
756 }
757 #endif
758 __setup("initcall_blacklist=", initcall_blacklist);
759 
760 static int __init_or_module do_one_initcall_debug(initcall_t fn)
761 {
762         ktime_t calltime, delta, rettime;
763         unsigned long long duration;
764         int ret;
765 
766         printk(KERN_DEBUG "calling  %pF @ %i\n", fn, task_pid_nr(current));
767         calltime = ktime_get();
768         ret = fn();
769         rettime = ktime_get();
770         delta = ktime_sub(rettime, calltime);
771         duration = (unsigned long long) ktime_to_ns(delta) >> 10;
772         printk(KERN_DEBUG "initcall %pF returned %d after %lld usecs\n",
773                  fn, ret, duration);
774 
775         return ret;
776 }
777 
778 int __init_or_module do_one_initcall(initcall_t fn)
779 {
780         int count = preempt_count();
781         int ret;
782         char msgbuf[64];
783 
784         if (initcall_blacklisted(fn))
785                 return -EPERM;
786 
787         if (initcall_debug)
788                 ret = do_one_initcall_debug(fn);
789         else
790                 ret = fn();
791 
792         msgbuf[0] = 0;
793 
794         if (preempt_count() != count) {
795                 sprintf(msgbuf, "preemption imbalance ");
796                 preempt_count_set(count);
797         }
798         if (irqs_disabled()) {
799                 strlcat(msgbuf, "disabled interrupts ", sizeof(msgbuf));
800                 local_irq_enable();
801         }
802         WARN(msgbuf[0], "initcall %pF returned with %s\n", fn, msgbuf);
803 
804         return ret;
805 }
806 
807 
808 extern initcall_t __initcall_start[];
809 extern initcall_t __initcall0_start[];
810 extern initcall_t __initcall1_start[];
811 extern initcall_t __initcall2_start[];
812 extern initcall_t __initcall3_start[];
813 extern initcall_t __initcall4_start[];
814 extern initcall_t __initcall5_start[];
815 extern initcall_t __initcall6_start[];
816 extern initcall_t __initcall7_start[];
817 extern initcall_t __initcall_end[];
818 
819 static initcall_t *initcall_levels[] __initdata = {
820         __initcall0_start,
821         __initcall1_start,
822         __initcall2_start,
823         __initcall3_start,
824         __initcall4_start,
825         __initcall5_start,
826         __initcall6_start,
827         __initcall7_start,
828         __initcall_end,
829 };
830 
831 /* Keep these in sync with initcalls in include/linux/init.h */
832 static char *initcall_level_names[] __initdata = {
833         "early",
834         "core",
835         "postcore",
836         "arch",
837         "subsys",
838         "fs",
839         "device",
840         "late",
841 };
842 
843 static void __init do_initcall_level(int level)
844 {
845         extern const struct kernel_param __start___param[], __stop___param[];
846         initcall_t *fn;
847 
848         strcpy(initcall_command_line, saved_command_line);
849         parse_args(initcall_level_names[level],
850                    initcall_command_line, __start___param,
851                    __stop___param - __start___param,
852                    level, level,
853                    &repair_env_string);
854 
855         for (fn = initcall_levels[level]; fn < initcall_levels[level+1]; fn++)
856                 do_one_initcall(*fn);
857 }
858 
859 static void __init do_initcalls(void)
860 {
861         int level;
862 
863         for (level = 0; level < ARRAY_SIZE(initcall_levels) - 1; level++)
864                 do_initcall_level(level);
865 }
866 
867 /*
868  * Ok, the machine is now initialized. None of the devices
869  * have been touched yet, but the CPU subsystem is up and
870  * running, and memory and process management works.
871  *
872  * Now we can finally start doing some real work..
873  */
874 static void __init do_basic_setup(void)
875 {
876         cpuset_init_smp();
877         usermodehelper_init();
878         shmem_init();
879         driver_init();
880         init_irq_proc();
881         do_ctors();
882         usermodehelper_enable();
883         do_initcalls();
884         random_int_secret_init();
885 }
886 
887 static void __init do_pre_smp_initcalls(void)
888 {
889         initcall_t *fn;
890 
891         for (fn = __initcall_start; fn < __initcall0_start; fn++)
892                 do_one_initcall(*fn);
893 }
894 
895 /*
896  * This function requests modules which should be loaded by default and is
897  * called twice right after initrd is mounted and right before init is
898  * exec'd.  If such modules are on either initrd or rootfs, they will be
899  * loaded before control is passed to userland.
900  */
901 void __init load_default_modules(void)
902 {
903         load_default_elevator_module();
904 }
905 
906 static int run_init_process(const char *init_filename)
907 {
908         argv_init[0] = init_filename;
909         return do_execve(getname_kernel(init_filename),
910                 (const char __user *const __user *)argv_init,
911                 (const char __user *const __user *)envp_init);
912 }
913 
914 static int try_to_run_init_process(const char *init_filename)
915 {
916         int ret;
917 
918         ret = run_init_process(init_filename);
919 
920         if (ret && ret != -ENOENT) {
921                 pr_err("Starting init: %s exists but couldn't execute it (error %d)\n",
922                        init_filename, ret);
923         }
924 
925         return ret;
926 }
927 
928 static noinline void __init kernel_init_freeable(void);
929 
930 static int __ref kernel_init(void *unused)
931 {
932         int ret;
933 
934         kernel_init_freeable();
935         /* need to finish all async __init code before freeing the memory */
936         async_synchronize_full();
937         free_initmem();
938         mark_rodata_ro();
939         system_state = SYSTEM_RUNNING;
940         numa_default_policy();
941 
942         flush_delayed_fput();
943 
944         if (ramdisk_execute_command) {
945                 ret = run_init_process(ramdisk_execute_command);
946                 if (!ret)
947                         return 0;
948                 pr_err("Failed to execute %s (error %d)\n",
949                        ramdisk_execute_command, ret);
950         }
951 
952         /*
953          * We try each of these until one succeeds.
954          *
955          * The Bourne shell can be used instead of init if we are
956          * trying to recover a really broken machine.
957          */
958         if (execute_command) {
959                 ret = run_init_process(execute_command);
960                 if (!ret)
961                         return 0;
962                 pr_err("Failed to execute %s (error %d).  Attempting defaults...\n",
963                         execute_command, ret);
964         }
965         if (!try_to_run_init_process("/sbin/init") ||
966             !try_to_run_init_process("/etc/init") ||
967             !try_to_run_init_process("/bin/init") ||
968             !try_to_run_init_process("/bin/sh"))
969                 return 0;
970 
971         panic("No working init found.  Try passing init= option to kernel. "
972               "See Linux Documentation/init.txt for guidance.");
973 }
974 
975 static noinline void __init kernel_init_freeable(void)
976 {
977         /*
978          * Wait until kthreadd is all set-up.
979          */
980         wait_for_completion(&kthreadd_done);
981 
982         /* Now the scheduler is fully set up and can do blocking allocations */
983         gfp_allowed_mask = __GFP_BITS_MASK;
984 
985         /*
986          * init can allocate pages on any node
987          */
988         set_mems_allowed(node_states[N_MEMORY]);
989         /*
990          * init can run on any cpu.
991          */
992         set_cpus_allowed_ptr(current, cpu_all_mask);
993 
994         cad_pid = task_pid(current);
995 
996         smp_prepare_cpus(setup_max_cpus);
997 
998         do_pre_smp_initcalls();
999         lockup_detector_init();
1000 
1001         smp_init();
1002         sched_init_smp();
1003 
1004         do_basic_setup();
1005 
1006         /* Open the /dev/console on the rootfs, this should never fail */
1007         if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0)
1008                 pr_err("Warning: unable to open an initial console.\n");
1009 
1010         (void) sys_dup(0);
1011         (void) sys_dup(0);
1012         /*
1013          * check if there is an early userspace init.  If yes, let it do all
1014          * the work
1015          */
1016 
1017         if (!ramdisk_execute_command)
1018                 ramdisk_execute_command = "/init";
1019 
1020         if (sys_access((const char __user *) ramdisk_execute_command, 0) != 0) {
1021                 ramdisk_execute_command = NULL;
1022                 prepare_namespace();
1023         }
1024 
1025         /*
1026          * Ok, we have completed the initial bootup, and
1027          * we're essentially up and running. Get rid of the
1028          * initmem segments and start the user-mode stuff..
1029          */
1030 
1031         /* rootfs is available now, try loading default modules */
1032         load_default_modules();
1033 }
1034 

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