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