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32 results

main.c

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  • main.c 29.29 KiB
    /*
     *  linux/init/main.c
     *
     *  Copyright (C) 1991, 1992  Linus Torvalds
     *
     *  GK 2/5/95  -  Changed to support mounting root fs via NFS
     *  Added initrd & change_root: Werner Almesberger & Hans Lermen, Feb '96
     *  Moan early if gcc is old, avoiding bogus kernels - Paul Gortmaker, May '96
     *  Simplified starting of init:  Michael A. Griffith <grif@acm.org>
     */
    
    #define DEBUG		/* Enable initcall_debug */
    
    #include <linux/types.h>
    #include <linux/extable.h>
    #include <linux/module.h>
    #include <linux/proc_fs.h>
    #include <linux/binfmts.h>
    #include <linux/kernel.h>
    #include <linux/syscalls.h>
    #include <linux/stackprotector.h>
    #include <linux/string.h>
    #include <linux/ctype.h>
    #include <linux/delay.h>
    #include <linux/ioport.h>
    #include <linux/init.h>
    #include <linux/initrd.h>
    #include <linux/memblock.h>
    #include <linux/acpi.h>
    #include <linux/console.h>
    #include <linux/nmi.h>
    #include <linux/percpu.h>
    #include <linux/kmod.h>
    #include <linux/vmalloc.h>
    #include <linux/kernel_stat.h>
    #include <linux/start_kernel.h>
    #include <linux/security.h>
    #include <linux/smp.h>
    #include <linux/profile.h>
    #include <linux/rcupdate.h>
    #include <linux/moduleparam.h>
    #include <linux/kallsyms.h>
    #include <linux/writeback.h>
    #include <linux/cpu.h>
    #include <linux/cpuset.h>
    #include <linux/cgroup.h>
    #include <linux/efi.h>
    #include <linux/tick.h>
    #include <linux/sched/isolation.h>
    #include <linux/interrupt.h>
    #include <linux/taskstats_kern.h>
    #include <linux/delayacct.h>
    #include <linux/unistd.h>
    #include <linux/utsname.h>
    #include <linux/rmap.h>
    #include <linux/mempolicy.h>
    #include <linux/key.h>
    #include <linux/buffer_head.h>
    #include <linux/page_ext.h>
    #include <linux/debug_locks.h>
    #include <linux/debugobjects.h>
    #include <linux/lockdep.h>
    #include <linux/kmemleak.h>
    #include <linux/pid_namespace.h>
    #include <linux/device.h>
    #include <linux/kthread.h>
    #include <linux/sched.h>
    #include <linux/sched/init.h>
    #include <linux/signal.h>
    #include <linux/idr.h>
    #include <linux/kgdb.h>
    #include <linux/ftrace.h>
    #include <linux/async.h>
    #include <linux/sfi.h>
    #include <linux/shmem_fs.h>
    #include <linux/slab.h>
    #include <linux/perf_event.h>
    #include <linux/ptrace.h>
    #include <linux/pti.h>
    #include <linux/blkdev.h>
    #include <linux/elevator.h>
    #include <linux/sched/clock.h>
    #include <linux/sched/task.h>
    #include <linux/sched/task_stack.h>
    #include <linux/context_tracking.h>
    #include <linux/random.h>
    #include <linux/list.h>
    #include <linux/integrity.h>
    #include <linux/proc_ns.h>
    #include <linux/io.h>
    #include <linux/cache.h>
    #include <linux/rodata_test.h>
    #include <linux/jump_label.h>
    #include <linux/mem_encrypt.h>
    
    #include <asm/io.h>
    #include <asm/bugs.h>
    #include <asm/setup.h>
    #include <asm/sections.h>
    #include <asm/cacheflush.h>
    
    #define CREATE_TRACE_POINTS
    #include <trace/events/initcall.h>
    
    static int kernel_init(void *);
    
    extern void init_IRQ(void);
    extern void radix_tree_init(void);
    
    /*
     * Debug helper: via this flag we know that we are in 'early bootup code'
     * where only the boot processor is running with IRQ disabled.  This means
     * two things - IRQ must not be enabled before the flag is cleared and some
     * operations which are not allowed with IRQ disabled are allowed while the
     * flag is set.
     */
    bool early_boot_irqs_disabled __read_mostly;
    
    enum system_states system_state __read_mostly;
    EXPORT_SYMBOL(system_state);
    
    /*
     * Boot command-line arguments
     */
    #define MAX_INIT_ARGS CONFIG_INIT_ENV_ARG_LIMIT
    #define MAX_INIT_ENVS CONFIG_INIT_ENV_ARG_LIMIT
    
    extern void time_init(void);
    /* Default late time init is NULL. archs can override this later. */
    void (*__initdata late_time_init)(void);
    
    /* Untouched command line saved by arch-specific code. */
    char __initdata boot_command_line[COMMAND_LINE_SIZE];
    /* Untouched saved command line (eg. for /proc) */
    char *saved_command_line;
    /* Command line for parameter parsing */
    static char *static_command_line;
    /* Command line for per-initcall parameter parsing */
    static char *initcall_command_line;
    
    static char *execute_command;
    static char *ramdisk_execute_command;
    
    /*
     * Used to generate warnings if static_key manipulation functions are used
     * before jump_label_init is called.
     */
    bool static_key_initialized __read_mostly;
    EXPORT_SYMBOL_GPL(static_key_initialized);
    
    /*
     * If set, this is an indication to the drivers that reset the underlying
     * device before going ahead with the initialization otherwise driver might
     * rely on the BIOS and skip the reset operation.
     *
     * This is useful if kernel is booting in an unreliable environment.
     * For ex. kdump situation where previous kernel has crashed, BIOS has been
     * skipped and devices will be in unknown state.
     */
    unsigned int reset_devices;
    EXPORT_SYMBOL(reset_devices);
    
    static int __init set_reset_devices(char *str)
    {
    	reset_devices = 1;
    	return 1;
    }
    
    __setup("reset_devices", set_reset_devices);
    
    static const char *argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
    const char *envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, };
    static const char *panic_later, *panic_param;
    
    extern const struct obs_kernel_param __setup_start[], __setup_end[];
    
    static bool __init obsolete_checksetup(char *line)
    {
    	const struct obs_kernel_param *p;
    	bool had_early_param = false;
    
    	p = __setup_start;
    	do {
    		int n = strlen(p->str);
    		if (parameqn(line, p->str, n)) {
    			if (p->early) {
    				/* Already done in parse_early_param?
    				 * (Needs exact match on param part).
    				 * Keep iterating, as we can have early
    				 * params and __setups of same names 8( */
    				if (line[n] == '\0' || line[n] == '=')
    					had_early_param = true;
    			} else if (!p->setup_func) {
    				pr_warn("Parameter %s is obsolete, ignored\n",
    					p->str);
    				return true;
    			} else if (p->setup_func(line + n))
    				return true;
    		}
    		p++;
    	} while (p < __setup_end);
    
    	return had_early_param;
    }
    
    /*
     * This should be approx 2 Bo*oMips to start (note initial shift), and will
     * still work even if initially too large, it will just take slightly longer
     */
    unsigned long loops_per_jiffy = (1<<12);
    EXPORT_SYMBOL(loops_per_jiffy);
    
    static int __init debug_kernel(char *str)
    {
    	console_loglevel = CONSOLE_LOGLEVEL_DEBUG;
    	return 0;
    }
    
    static int __init quiet_kernel(char *str)
    {
    	console_loglevel = CONSOLE_LOGLEVEL_QUIET;
    	return 0;
    }
    
    early_param("debug", debug_kernel);
    early_param("quiet", quiet_kernel);
    
    static int __init loglevel(char *str)
    {
    	int newlevel;
    
    	/*
    	 * Only update loglevel value when a correct setting was passed,
    	 * to prevent blind crashes (when loglevel being set to 0) that
    	 * are quite hard to debug
    	 */
    	if (get_option(&str, &newlevel)) {
    		console_loglevel = newlevel;
    		return 0;
    	}
    
    	return -EINVAL;
    }
    
    early_param("loglevel", loglevel);
    
    /* Change NUL term back to "=", to make "param" the whole string. */
    static int __init repair_env_string(char *param, char *val,
    				    const char *unused, void *arg)
    {
    	if (val) {
    		/* param=val or param="val"? */
    		if (val == param+strlen(param)+1)
    			val[-1] = '=';
    		else if (val == param+strlen(param)+2) {
    			val[-2] = '=';
    			memmove(val-1, val, strlen(val)+1);
    			val--;
    		} else
    			BUG();
    	}
    	return 0;
    }
    
    /* Anything after -- gets handed straight to init. */
    static int __init set_init_arg(char *param, char *val,
    			       const char *unused, void *arg)
    {
    	unsigned int i;
    
    	if (panic_later)
    		return 0;
    
    	repair_env_string(param, val, unused, NULL);
    
    	for (i = 0; argv_init[i]; i++) {
    		if (i == MAX_INIT_ARGS) {
    			panic_later = "init";
    			panic_param = param;
    			return 0;
    		}
    	}
    	argv_init[i] = param;
    	return 0;
    }
    
    /*
     * Unknown boot options get handed to init, unless they look like
     * unused parameters (modprobe will find them in /proc/cmdline).
     */
    static int __init unknown_bootoption(char *param, char *val,
    				     const char *unused, void *arg)
    {
    	repair_env_string(param, val, unused, NULL);
    
    	/* Handle obsolete-style parameters */
    	if (obsolete_checksetup(param))
    		return 0;
    
    	/* Unused module parameter. */
    	if (strchr(param, '.') && (!val || strchr(param, '.') < val))
    		return 0;
    
    	if (panic_later)
    		return 0;
    
    	if (val) {
    		/* Environment option */
    		unsigned int i;
    		for (i = 0; envp_init[i]; i++) {
    			if (i == MAX_INIT_ENVS) {
    				panic_later = "env";
    				panic_param = param;
    			}
    			if (!strncmp(param, envp_init[i], val - param))
    				break;
    		}
    		envp_init[i] = param;
    	} else {
    		/* Command line option */
    		unsigned int i;
    		for (i = 0; argv_init[i]; i++) {
    			if (i == MAX_INIT_ARGS) {
    				panic_later = "init";
    				panic_param = param;
    			}
    		}
    		argv_init[i] = param;
    	}
    	return 0;
    }
    
    static int __init init_setup(char *str)
    {
    	unsigned int i;
    
    	execute_command = str;
    	/*
    	 * In case LILO is going to boot us with default command line,
    	 * it prepends "auto" before the whole cmdline which makes
    	 * the shell think it should execute a script with such name.
    	 * So we ignore all arguments entered _before_ init=... [MJ]
    	 */
    	for (i = 1; i < MAX_INIT_ARGS; i++)
    		argv_init[i] = NULL;
    	return 1;
    }
    __setup("init=", init_setup);
    
    static int __init rdinit_setup(char *str)
    {
    	unsigned int i;
    
    	ramdisk_execute_command = str;
    	/* See "auto" comment in init_setup */
    	for (i = 1; i < MAX_INIT_ARGS; i++)
    		argv_init[i] = NULL;
    	return 1;
    }
    __setup("rdinit=", rdinit_setup);
    
    #ifndef CONFIG_SMP
    static const unsigned int setup_max_cpus = NR_CPUS;
    static inline void setup_nr_cpu_ids(void) { }
    static inline void smp_prepare_cpus(unsigned int maxcpus) { }
    #endif
    
    /*
     * We need to store the untouched command line for future reference.
     * We also need to store the touched command line since the parameter
     * parsing is performed in place, and we should allow a component to
     * store reference of name/value for future reference.
     */
    static void __init setup_command_line(char *command_line)
    {
    	size_t len = strlen(boot_command_line) + 1;
    
    	saved_command_line = memblock_alloc(len, SMP_CACHE_BYTES);
    	if (!saved_command_line)
    		panic("%s: Failed to allocate %zu bytes\n", __func__, len);
    
    	initcall_command_line =	memblock_alloc(len, SMP_CACHE_BYTES);
    	if (!initcall_command_line)
    		panic("%s: Failed to allocate %zu bytes\n", __func__, len);
    
    	static_command_line = memblock_alloc(len, SMP_CACHE_BYTES);
    	if (!static_command_line)
    		panic("%s: Failed to allocate %zu bytes\n", __func__, len);
    
    	strcpy(saved_command_line, boot_command_line);
    	strcpy(static_command_line, command_line);
    }
    
    /*
     * We need to finalize in a non-__init function or else race conditions
     * between the root thread and the init thread may cause start_kernel to
     * be reaped by free_initmem before the root thread has proceeded to
     * cpu_idle.
     *
     * gcc-3.4 accidentally inlines this function, so use noinline.
     */
    
    static __initdata DECLARE_COMPLETION(kthreadd_done);
    
    noinline void __ref rest_init(void)
    {
    	struct task_struct *tsk;
    	int pid;
    
    	rcu_scheduler_starting();
    	/*
    	 * We need to spawn init first so that it obtains pid 1, however
    	 * the init task will end up wanting to create kthreads, which, if
    	 * we schedule it before we create kthreadd, will OOPS.
    	 */
    	pid = kernel_thread(kernel_init, NULL, CLONE_FS);
    	/*
    	 * Pin init on the boot CPU. Task migration is not properly working
    	 * until sched_init_smp() has been run. It will set the allowed
    	 * CPUs for init to the non isolated CPUs.
    	 */
    	rcu_read_lock();
    	tsk = find_task_by_pid_ns(pid, &init_pid_ns);
    	set_cpus_allowed_ptr(tsk, cpumask_of(smp_processor_id()));
    	rcu_read_unlock();
    
    	numa_default_policy();
    	pid = kernel_thread(kthreadd, NULL, CLONE_FS | CLONE_FILES);
    	rcu_read_lock();
    	kthreadd_task = find_task_by_pid_ns(pid, &init_pid_ns);
    	rcu_read_unlock();
    
    	/*
    	 * Enable might_sleep() and smp_processor_id() checks.
    	 * They cannot be enabled earlier because with CONFIG_PREEMPT=y
    	 * kernel_thread() would trigger might_sleep() splats. With
    	 * CONFIG_PREEMPT_VOLUNTARY=y the init task might have scheduled
    	 * already, but it's stuck on the kthreadd_done completion.
    	 */
    	system_state = SYSTEM_SCHEDULING;
    
    	complete(&kthreadd_done);
    
    	/*
    	 * The boot idle thread must execute schedule()
    	 * at least once to get things moving:
    	 */
    	schedule_preempt_disabled();
    	/* Call into cpu_idle with preempt disabled */
    	cpu_startup_entry(CPUHP_ONLINE);
    }
    
    /* Check for early params. */
    static int __init do_early_param(char *param, char *val,
    				 const char *unused, void *arg)
    {
    	const struct obs_kernel_param *p;
    
    	for (p = __setup_start; p < __setup_end; p++) {
    		if ((p->early && parameq(param, p->str)) ||
    		    (strcmp(param, "console") == 0 &&
    		     strcmp(p->str, "earlycon") == 0)
    		) {
    			if (p->setup_func(val) != 0)
    				pr_warn("Malformed early option '%s'\n", param);
    		}
    	}
    	/* We accept everything at this stage. */
    	return 0;
    }
    
    void __init parse_early_options(char *cmdline)
    {
    	parse_args("early options", cmdline, NULL, 0, 0, 0, NULL,
    		   do_early_param);
    }
    
    /* Arch code calls this early on, or if not, just before other parsing. */
    void __init parse_early_param(void)
    {
    	static int done __initdata;
    	static char tmp_cmdline[COMMAND_LINE_SIZE] __initdata;
    
    	if (done)
    		return;
    
    	/* All fall through to do_early_param. */
    	strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);
    	parse_early_options(tmp_cmdline);
    	done = 1;
    }
    
    void __init __weak arch_post_acpi_subsys_init(void) { }
    
    void __init __weak smp_setup_processor_id(void)
    {
    }
    
    # if THREAD_SIZE >= PAGE_SIZE
    void __init __weak thread_stack_cache_init(void)
    {
    }
    #endif
    
    void __init __weak mem_encrypt_init(void) { }
    
    void __init __weak poking_init(void) { }
    
    void __init __weak pgd_cache_init(void) { }
    
    bool initcall_debug;
    core_param(initcall_debug, initcall_debug, bool, 0644);
    
    #ifdef TRACEPOINTS_ENABLED
    static void __init initcall_debug_enable(void);
    #else
    static inline void initcall_debug_enable(void)
    {
    }
    #endif
    
    /*
     * Set up kernel memory allocators
     */
    static void __init mm_init(void)
    {
    	/*
    	 * page_ext requires contiguous pages,
    	 * bigger than MAX_ORDER unless SPARSEMEM.
    	 */
    	page_ext_init_flatmem();
    	mem_init();
    	kmem_cache_init();
    	pgtable_init();
    	debug_objects_mem_init();
    	vmalloc_init();
    	ioremap_huge_init();
    	/* Should be run before the first non-init thread is created */
    	init_espfix_bsp();
    	/* Should be run after espfix64 is set up. */
    	pti_init();
    	pgd_cache_init();
    }
    
    void __init __weak arch_call_rest_init(void)
    {
    	rest_init();
    }
    
    asmlinkage __visible void __init start_kernel(void)
    {
    	char *command_line;
    	char *after_dashes;
    
    	set_task_stack_end_magic(&init_task);
    	smp_setup_processor_id();
    	debug_objects_early_init();
    
    	cgroup_init_early();
    
    	local_irq_disable();
    	early_boot_irqs_disabled = true;
    
    	/*
    	 * Interrupts are still disabled. Do necessary setups, then
    	 * enable them.
    	 */
    	boot_cpu_init();
    	page_address_init();
    	pr_notice("%s", linux_banner);
    	setup_arch(&command_line);
    	mm_init_cpumask(&init_mm);
    	setup_command_line(command_line);
    	setup_nr_cpu_ids();
    	setup_per_cpu_areas();
    	smp_prepare_boot_cpu();	/* arch-specific boot-cpu hooks */
    	boot_cpu_hotplug_init();
    
    	build_all_zonelists(NULL);
    	page_alloc_init();
    
    	pr_notice("Kernel command line: %s\n", boot_command_line);
    	/* parameters may set static keys */
    	jump_label_init();
    	parse_early_param();
    	after_dashes = parse_args("Booting kernel",
    				  static_command_line, __start___param,
    				  __stop___param - __start___param,
    				  -1, -1, NULL, &unknown_bootoption);
    	if (!IS_ERR_OR_NULL(after_dashes))
    		parse_args("Setting init args", after_dashes, NULL, 0, -1, -1,
    			   NULL, set_init_arg);
    
    	/*
    	 * These use large bootmem allocations and must precede
    	 * kmem_cache_init()
    	 */
    	setup_log_buf(0);
    	vfs_caches_init_early();
    	sort_main_extable();
    	trap_init();
    	mm_init();
    
    	ftrace_init();
    
    	/* trace_printk can be enabled here */
    	early_trace_init();
    
    	/*
    	 * Set up the scheduler prior starting any interrupts (such as the
    	 * timer interrupt). Full topology setup happens at smp_init()
    	 * time - but meanwhile we still have a functioning scheduler.
    	 */
    	sched_init();
    	/*
    	 * Disable preemption - early bootup scheduling is extremely
    	 * fragile until we cpu_idle() for the first time.
    	 */
    	preempt_disable();
    	if (WARN(!irqs_disabled(),
    		 "Interrupts were enabled *very* early, fixing it\n"))
    		local_irq_disable();
    	radix_tree_init();
    
    	/*
    	 * Set up housekeeping before setting up workqueues to allow the unbound
    	 * workqueue to take non-housekeeping into account.
    	 */
    	housekeeping_init();
    
    	/*
    	 * Allow workqueue creation and work item queueing/cancelling
    	 * early.  Work item execution depends on kthreads and starts after
    	 * workqueue_init().
    	 */
    	workqueue_init_early();
    
    	rcu_init();
    
    	/* Trace events are available after this */
    	trace_init();
    
    	if (initcall_debug)
    		initcall_debug_enable();
    
    	context_tracking_init();
    	/* init some links before init_ISA_irqs() */
    	early_irq_init();
    	init_IRQ();
    	tick_init();
    	rcu_init_nohz();
    	init_timers();
    	hrtimers_init();
    	softirq_init();
    	timekeeping_init();
    
    	/*
    	 * For best initial stack canary entropy, prepare it after:
    	 * - setup_arch() for any UEFI RNG entropy and boot cmdline access
    	 * - timekeeping_init() for ktime entropy used in rand_initialize()
    	 * - rand_initialize() to get any arch-specific entropy like RDRAND
    	 * - add_latent_entropy() to get any latent entropy
    	 * - adding command line entropy
    	 */
    	rand_initialize();
    	add_latent_entropy();
    	add_device_randomness(command_line, strlen(command_line));
    	boot_init_stack_canary();
    
    	time_init();
    	printk_safe_init();
    	perf_event_init();
    	profile_init();
    	call_function_init();
    	WARN(!irqs_disabled(), "Interrupts were enabled early\n");
    
    	early_boot_irqs_disabled = false;
    	local_irq_enable();
    
    	kmem_cache_init_late();
    
    	/*
    	 * HACK ALERT! This is early. We're enabling the console before
    	 * we've done PCI setups etc, and console_init() must be aware of
    	 * this. But we do want output early, in case something goes wrong.
    	 */
    	console_init();
    	if (panic_later)
    		panic("Too many boot %s vars at `%s'", panic_later,
    		      panic_param);
    
    	lockdep_init();
    
    	/*
    	 * Need to run this when irqs are enabled, because it wants
    	 * to self-test [hard/soft]-irqs on/off lock inversion bugs
    	 * too:
    	 */
    	locking_selftest();
    
    	/*
    	 * This needs to be called before any devices perform DMA
    	 * operations that might use the SWIOTLB bounce buffers. It will
    	 * mark the bounce buffers as decrypted so that their usage will
    	 * not cause "plain-text" data to be decrypted when accessed.
    	 */
    	mem_encrypt_init();
    
    #ifdef CONFIG_BLK_DEV_INITRD
    	if (initrd_start && !initrd_below_start_ok &&
    	    page_to_pfn(virt_to_page((void *)initrd_start)) < min_low_pfn) {
    		pr_crit("initrd overwritten (0x%08lx < 0x%08lx) - disabling it.\n",
    		    page_to_pfn(virt_to_page((void *)initrd_start)),
    		    min_low_pfn);
    		initrd_start = 0;
    	}
    #endif
    	kmemleak_init();
    	setup_per_cpu_pageset();
    	numa_policy_init();
    	acpi_early_init();
    	if (late_time_init)
    		late_time_init();
    	sched_clock_init();
    	calibrate_delay();
    	pid_idr_init();
    	anon_vma_init();
    #ifdef CONFIG_X86
    	if (efi_enabled(EFI_RUNTIME_SERVICES))
    		efi_enter_virtual_mode();
    #endif
    	thread_stack_cache_init();
    	cred_init();
    	fork_init();
    	proc_caches_init();
    	uts_ns_init();
    	buffer_init();
    	key_init();
    	security_init();
    	dbg_late_init();
    	vfs_caches_init();
    	pagecache_init();
    	signals_init();
    	seq_file_init();
    	proc_root_init();
    	nsfs_init();
    	cpuset_init();
    	cgroup_init();
    	taskstats_init_early();
    	delayacct_init();
    
    	poking_init();
    	check_bugs();
    
    	acpi_subsystem_init();
    	arch_post_acpi_subsys_init();
    	sfi_init_late();
    
    	/* Do the rest non-__init'ed, we're now alive */
    	arch_call_rest_init();
    }
    
    /* Call all constructor functions linked into the kernel. */
    static void __init do_ctors(void)
    {
    #ifdef CONFIG_CONSTRUCTORS
    	ctor_fn_t *fn = (ctor_fn_t *) __ctors_start;
    
    	for (; fn < (ctor_fn_t *) __ctors_end; fn++)
    		(*fn)();
    #endif
    }
    
    #ifdef CONFIG_KALLSYMS
    struct blacklist_entry {
    	struct list_head next;
    	char *buf;
    };
    
    static __initdata_or_module LIST_HEAD(blacklisted_initcalls);
    
    static int __init initcall_blacklist(char *str)
    {
    	char *str_entry;
    	struct blacklist_entry *entry;
    
    	/* str argument is a comma-separated list of functions */
    	do {
    		str_entry = strsep(&str, ",");
    		if (str_entry) {
    			pr_debug("blacklisting initcall %s\n", str_entry);
    			entry = memblock_alloc(sizeof(*entry),
    					       SMP_CACHE_BYTES);
    			if (!entry)
    				panic("%s: Failed to allocate %zu bytes\n",
    				      __func__, sizeof(*entry));
    			entry->buf = memblock_alloc(strlen(str_entry) + 1,
    						    SMP_CACHE_BYTES);
    			if (!entry->buf)
    				panic("%s: Failed to allocate %zu bytes\n",
    				      __func__, strlen(str_entry) + 1);
    			strcpy(entry->buf, str_entry);
    			list_add(&entry->next, &blacklisted_initcalls);
    		}
    	} while (str_entry);
    
    	return 0;
    }
    
    static bool __init_or_module initcall_blacklisted(initcall_t fn)
    {
    	struct blacklist_entry *entry;
    	char fn_name[KSYM_SYMBOL_LEN];
    	unsigned long addr;
    
    	if (list_empty(&blacklisted_initcalls))
    		return false;
    
    	addr = (unsigned long) dereference_function_descriptor(fn);
    	sprint_symbol_no_offset(fn_name, addr);
    
    	/*
    	 * fn will be "function_name [module_name]" where [module_name] is not
    	 * displayed for built-in init functions.  Strip off the [module_name].
    	 */
    	strreplace(fn_name, ' ', '\0');
    
    	list_for_each_entry(entry, &blacklisted_initcalls, next) {
    		if (!strcmp(fn_name, entry->buf)) {
    			pr_debug("initcall %s blacklisted\n", fn_name);
    			return true;
    		}
    	}
    
    	return false;
    }
    #else
    static int __init initcall_blacklist(char *str)
    {
    	pr_warn("initcall_blacklist requires CONFIG_KALLSYMS\n");
    	return 0;
    }
    
    static bool __init_or_module initcall_blacklisted(initcall_t fn)
    {
    	return false;
    }
    #endif
    __setup("initcall_blacklist=", initcall_blacklist);
    
    static __init_or_module void
    trace_initcall_start_cb(void *data, initcall_t fn)
    {
    	ktime_t *calltime = (ktime_t *)data;
    
    	printk(KERN_DEBUG "calling  %pS @ %i\n", fn, task_pid_nr(current));
    	*calltime = ktime_get();
    }
    
    static __init_or_module void
    trace_initcall_finish_cb(void *data, initcall_t fn, int ret)
    {
    	ktime_t *calltime = (ktime_t *)data;
    	ktime_t delta, rettime;
    	unsigned long long duration;
    
    	rettime = ktime_get();
    	delta = ktime_sub(rettime, *calltime);
    	duration = (unsigned long long) ktime_to_ns(delta) >> 10;
    	printk(KERN_DEBUG "initcall %pS returned %d after %lld usecs\n",
    		 fn, ret, duration);
    }
    
    static ktime_t initcall_calltime;
    
    #ifdef TRACEPOINTS_ENABLED
    static void __init initcall_debug_enable(void)
    {
    	int ret;
    
    	ret = register_trace_initcall_start(trace_initcall_start_cb,
    					    &initcall_calltime);
    	ret |= register_trace_initcall_finish(trace_initcall_finish_cb,
    					      &initcall_calltime);
    	WARN(ret, "Failed to register initcall tracepoints\n");
    }
    # define do_trace_initcall_start	trace_initcall_start
    # define do_trace_initcall_finish	trace_initcall_finish
    #else
    static inline void do_trace_initcall_start(initcall_t fn)
    {
    	if (!initcall_debug)
    		return;
    	trace_initcall_start_cb(&initcall_calltime, fn);
    }
    static inline void do_trace_initcall_finish(initcall_t fn, int ret)
    {
    	if (!initcall_debug)
    		return;
    	trace_initcall_finish_cb(&initcall_calltime, fn, ret);
    }
    #endif /* !TRACEPOINTS_ENABLED */
    
    int __init_or_module do_one_initcall(initcall_t fn)
    {
    	int count = preempt_count();
    	char msgbuf[64];
    	int ret;
    
    	if (initcall_blacklisted(fn))
    		return -EPERM;
    
    	do_trace_initcall_start(fn);
    	ret = fn();
    	do_trace_initcall_finish(fn, ret);
    
    	msgbuf[0] = 0;
    
    	if (preempt_count() != count) {
    		sprintf(msgbuf, "preemption imbalance ");
    		preempt_count_set(count);
    	}
    	if (irqs_disabled()) {
    		strlcat(msgbuf, "disabled interrupts ", sizeof(msgbuf));
    		local_irq_enable();
    	}
    	WARN(msgbuf[0], "initcall %pS returned with %s\n", fn, msgbuf);
    
    	add_latent_entropy();
    	return ret;
    }
    
    
    extern initcall_entry_t __initcall_start[];
    extern initcall_entry_t __initcall0_start[];
    extern initcall_entry_t __initcall1_start[];
    extern initcall_entry_t __initcall2_start[];
    extern initcall_entry_t __initcall3_start[];
    extern initcall_entry_t __initcall4_start[];
    extern initcall_entry_t __initcall5_start[];
    extern initcall_entry_t __initcall6_start[];
    extern initcall_entry_t __initcall7_start[];
    extern initcall_entry_t __initcall_end[];
    
    static initcall_entry_t *initcall_levels[] __initdata = {
    	__initcall0_start,
    	__initcall1_start,
    	__initcall2_start,
    	__initcall3_start,
    	__initcall4_start,
    	__initcall5_start,
    	__initcall6_start,
    	__initcall7_start,
    	__initcall_end,
    };
    
    /* Keep these in sync with initcalls in include/linux/init.h */
    static const char *initcall_level_names[] __initdata = {
    	"pure",
    	"core",
    	"postcore",
    	"arch",
    	"subsys",
    	"fs",
    	"device",
    	"late",
    };
    
    static void __init do_initcall_level(int level)
    {
    	initcall_entry_t *fn;
    
    	strcpy(initcall_command_line, saved_command_line);
    	parse_args(initcall_level_names[level],
    		   initcall_command_line, __start___param,
    		   __stop___param - __start___param,
    		   level, level,
    		   NULL, &repair_env_string);
    
    	trace_initcall_level(initcall_level_names[level]);
    	for (fn = initcall_levels[level]; fn < initcall_levels[level+1]; fn++)
    		do_one_initcall(initcall_from_entry(fn));
    }
    
    static void __init do_initcalls(void)
    {
    	int level;
    
    	for (level = 0; level < ARRAY_SIZE(initcall_levels) - 1; level++)
    		do_initcall_level(level);
    }
    
    /*
     * Ok, the machine is now initialized. None of the devices
     * have been touched yet, but the CPU subsystem is up and
     * running, and memory and process management works.
     *
     * Now we can finally start doing some real work..
     */
    static void __init do_basic_setup(void)
    {
    	cpuset_init_smp();
    	shmem_init();
    	driver_init();
    	init_irq_proc();
    	do_ctors();
    	usermodehelper_enable();
    	do_initcalls();
    }
    
    static void __init do_pre_smp_initcalls(void)
    {
    	initcall_entry_t *fn;
    
    	trace_initcall_level("early");
    	for (fn = __initcall_start; fn < __initcall0_start; fn++)
    		do_one_initcall(initcall_from_entry(fn));
    }
    
    static int run_init_process(const char *init_filename)
    {
    	argv_init[0] = init_filename;
    	pr_info("Run %s as init process\n", init_filename);
    	return do_execve(getname_kernel(init_filename),
    		(const char __user *const __user *)argv_init,
    		(const char __user *const __user *)envp_init);
    }
    
    static int try_to_run_init_process(const char *init_filename)
    {
    	int ret;
    
    	ret = run_init_process(init_filename);
    
    	if (ret && ret != -ENOENT) {
    		pr_err("Starting init: %s exists but couldn't execute it (error %d)\n",
    		       init_filename, ret);
    	}
    
    	return ret;
    }
    
    static noinline void __init kernel_init_freeable(void);
    
    #if defined(CONFIG_STRICT_KERNEL_RWX) || defined(CONFIG_STRICT_MODULE_RWX)
    bool rodata_enabled __ro_after_init = true;
    static int __init set_debug_rodata(char *str)
    {
    	return strtobool(str, &rodata_enabled);
    }
    __setup("rodata=", set_debug_rodata);
    #endif
    
    #ifdef CONFIG_STRICT_KERNEL_RWX
    static void mark_readonly(void)
    {
    	if (rodata_enabled) {
    		/*
    		 * load_module() results in W+X mappings, which are cleaned
    		 * up with call_rcu().  Let's make sure that queued work is
    		 * flushed so that we don't hit false positives looking for
    		 * insecure pages which are W+X.
    		 */
    		rcu_barrier();
    		mark_rodata_ro();
    		rodata_test();
    	} else
    		pr_info("Kernel memory protection disabled.\n");
    }
    #else
    static inline void mark_readonly(void)
    {
    	pr_warn("This architecture does not have kernel memory protection.\n");
    }
    #endif
    
    static int __ref kernel_init(void *unused)
    {
    	int ret;
    
    	kernel_init_freeable();
    	/* need to finish all async __init code before freeing the memory */
    	async_synchronize_full();
    	ftrace_free_init_mem();
    	free_initmem();
    	mark_readonly();
    
    	/*
    	 * Kernel mappings are now finalized - update the userspace page-table
    	 * to finalize PTI.
    	 */
    	pti_finalize();
    
    	system_state = SYSTEM_RUNNING;
    	numa_default_policy();
    
    	rcu_end_inkernel_boot();
    
    	if (ramdisk_execute_command) {
    		ret = run_init_process(ramdisk_execute_command);
    		if (!ret)
    			return 0;
    		pr_err("Failed to execute %s (error %d)\n",
    		       ramdisk_execute_command, ret);
    	}
    
    	/*
    	 * We try each of these until one succeeds.
    	 *
    	 * The Bourne shell can be used instead of init if we are
    	 * trying to recover a really broken machine.
    	 */
    	if (execute_command) {
    		ret = run_init_process(execute_command);
    		if (!ret)
    			return 0;
    		panic("Requested init %s failed (error %d).",
    		      execute_command, ret);
    	}
    	if (!try_to_run_init_process("/sbin/init") ||
    	    !try_to_run_init_process("/etc/init") ||
    	    !try_to_run_init_process("/bin/init") ||
    	    !try_to_run_init_process("/bin/sh"))
    		return 0;
    
    	panic("No working init found.  Try passing init= option to kernel. "
    	      "See Linux Documentation/admin-guide/init.rst for guidance.");
    }
    
    static noinline void __init kernel_init_freeable(void)
    {
    	/*
    	 * Wait until kthreadd is all set-up.
    	 */
    	wait_for_completion(&kthreadd_done);
    
    	/* Now the scheduler is fully set up and can do blocking allocations */
    	gfp_allowed_mask = __GFP_BITS_MASK;
    
    	/*
    	 * init can allocate pages on any node
    	 */
    	set_mems_allowed(node_states[N_MEMORY]);
    
    	cad_pid = task_pid(current);
    
    	smp_prepare_cpus(setup_max_cpus);
    
    	workqueue_init();
    
    	init_mm_internals();
    
    	do_pre_smp_initcalls();
    	lockup_detector_init();
    
    	smp_init();
    	sched_init_smp();
    
    	page_alloc_init_late();
    	/* Initialize page ext after all struct pages are initialized. */
    	page_ext_init();
    
    	do_basic_setup();
    
    	/* Open the /dev/console on the rootfs, this should never fail */
    	if (ksys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0)
    		pr_err("Warning: unable to open an initial console.\n");
    
    	(void) ksys_dup(0);
    	(void) ksys_dup(0);
    	/*
    	 * check if there is an early userspace init.  If yes, let it do all
    	 * the work
    	 */
    
    	if (!ramdisk_execute_command)
    		ramdisk_execute_command = "/init";
    
    	if (ksys_access((const char __user *)
    			ramdisk_execute_command, 0) != 0) {
    		ramdisk_execute_command = NULL;
    		prepare_namespace();
    	}
    
    	/*
    	 * Ok, we have completed the initial bootup, and
    	 * we're essentially up and running. Get rid of the
    	 * initmem segments and start the user-mode stuff..
    	 *
    	 * rootfs is available now, try loading the public keys
    	 * and default modules
    	 */
    
    	integrity_load_keys();
    }