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authorRobin Holt <holt@sgi.com>2013-07-08 16:01:32 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2013-07-09 10:33:29 -0700
commit15d94b82565ebfb0cf27830b96e6cf5ed2d12a9a (patch)
tree21aad9ff42bf328777956e835ef7962bc307da9a /kernel/reboot.c
parent0efbee70890c992f31a7b294ac654ff6c62d51c5 (diff)
reboot: move shutdown/reboot related functions to kernel/reboot.c
This patch is preparatory. It moves reboot related syscall, etc functions from kernel/sys.c to kernel/reboot.c. Signed-off-by: Robin Holt <holt@sgi.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Russ Anderson <rja@sgi.com> Cc: Robin Holt <holt@sgi.com> Cc: Russell King <rmk+kernel@arm.linux.org.uk> Cc: Guan Xuetao <gxt@mprc.pku.edu.cn> Cc: Ingo Molnar <mingo@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/reboot.c')
-rw-r--r--kernel/reboot.c346
1 files changed, 346 insertions, 0 deletions
diff --git a/kernel/reboot.c b/kernel/reboot.c
new file mode 100644
index 000000000000..37d2636a65c2
--- /dev/null
+++ b/kernel/reboot.c
@@ -0,0 +1,346 @@
+/*
+ * linux/kernel/reboot.c
+ *
+ * Copyright (C) 2013 Linus Torvalds
+ */
+
+#include <linux/export.h>
+#include <linux/kexec.h>
+#include <linux/kmod.h>
+#include <linux/kmsg_dump.h>
+#include <linux/reboot.h>
+#include <linux/suspend.h>
+#include <linux/syscalls.h>
+#include <linux/syscore_ops.h>
+#include <linux/uaccess.h>
+
+/*
+ * this indicates whether you can reboot with ctrl-alt-del: the default is yes
+ */
+
+int C_A_D = 1;
+struct pid *cad_pid;
+EXPORT_SYMBOL(cad_pid);
+
+/*
+ * If set, this is used for preparing the system to power off.
+ */
+
+void (*pm_power_off_prepare)(void);
+
+/**
+ * emergency_restart - reboot the system
+ *
+ * Without shutting down any hardware or taking any locks
+ * reboot the system. This is called when we know we are in
+ * trouble so this is our best effort to reboot. This is
+ * safe to call in interrupt context.
+ */
+void emergency_restart(void)
+{
+ kmsg_dump(KMSG_DUMP_EMERG);
+ machine_emergency_restart();
+}
+EXPORT_SYMBOL_GPL(emergency_restart);
+
+void kernel_restart_prepare(char *cmd)
+{
+ blocking_notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd);
+ system_state = SYSTEM_RESTART;
+ usermodehelper_disable();
+ device_shutdown();
+}
+
+/**
+ * register_reboot_notifier - Register function to be called at reboot time
+ * @nb: Info about notifier function to be called
+ *
+ * Registers a function with the list of functions
+ * to be called at reboot time.
+ *
+ * Currently always returns zero, as blocking_notifier_chain_register()
+ * always returns zero.
+ */
+int register_reboot_notifier(struct notifier_block *nb)
+{
+ return blocking_notifier_chain_register(&reboot_notifier_list, nb);
+}
+EXPORT_SYMBOL(register_reboot_notifier);
+
+/**
+ * unregister_reboot_notifier - Unregister previously registered reboot notifier
+ * @nb: Hook to be unregistered
+ *
+ * Unregisters a previously registered reboot
+ * notifier function.
+ *
+ * Returns zero on success, or %-ENOENT on failure.
+ */
+int unregister_reboot_notifier(struct notifier_block *nb)
+{
+ return blocking_notifier_chain_unregister(&reboot_notifier_list, nb);
+}
+EXPORT_SYMBOL(unregister_reboot_notifier);
+
+static void migrate_to_reboot_cpu(void)
+{
+ /* The boot cpu is always logical cpu 0 */
+ int cpu = 0;
+
+ cpu_hotplug_disable();
+
+ /* Make certain the cpu I'm about to reboot on is online */
+ if (!cpu_online(cpu))
+ cpu = cpumask_first(cpu_online_mask);
+
+ /* Prevent races with other tasks migrating this task */
+ current->flags |= PF_NO_SETAFFINITY;
+
+ /* Make certain I only run on the appropriate processor */
+ set_cpus_allowed_ptr(current, cpumask_of(cpu));
+}
+
+/**
+ * kernel_restart - reboot the system
+ * @cmd: pointer to buffer containing command to execute for restart
+ * or %NULL
+ *
+ * Shutdown everything and perform a clean reboot.
+ * This is not safe to call in interrupt context.
+ */
+void kernel_restart(char *cmd)
+{
+ kernel_restart_prepare(cmd);
+ migrate_to_reboot_cpu();
+ syscore_shutdown();
+ if (!cmd)
+ printk(KERN_EMERG "Restarting system.\n");
+ else
+ printk(KERN_EMERG "Restarting system with command '%s'.\n", cmd);
+ kmsg_dump(KMSG_DUMP_RESTART);
+ machine_restart(cmd);
+}
+EXPORT_SYMBOL_GPL(kernel_restart);
+
+static void kernel_shutdown_prepare(enum system_states state)
+{
+ blocking_notifier_call_chain(&reboot_notifier_list,
+ (state == SYSTEM_HALT)?SYS_HALT:SYS_POWER_OFF, NULL);
+ system_state = state;
+ usermodehelper_disable();
+ device_shutdown();
+}
+/**
+ * kernel_halt - halt the system
+ *
+ * Shutdown everything and perform a clean system halt.
+ */
+void kernel_halt(void)
+{
+ kernel_shutdown_prepare(SYSTEM_HALT);
+ migrate_to_reboot_cpu();
+ syscore_shutdown();
+ printk(KERN_EMERG "System halted.\n");
+ kmsg_dump(KMSG_DUMP_HALT);
+ machine_halt();
+}
+
+EXPORT_SYMBOL_GPL(kernel_halt);
+
+/**
+ * kernel_power_off - power_off the system
+ *
+ * Shutdown everything and perform a clean system power_off.
+ */
+void kernel_power_off(void)
+{
+ kernel_shutdown_prepare(SYSTEM_POWER_OFF);
+ if (pm_power_off_prepare)
+ pm_power_off_prepare();
+ migrate_to_reboot_cpu();
+ syscore_shutdown();
+ printk(KERN_EMERG "Power down.\n");
+ kmsg_dump(KMSG_DUMP_POWEROFF);
+ machine_power_off();
+}
+EXPORT_SYMBOL_GPL(kernel_power_off);
+
+static DEFINE_MUTEX(reboot_mutex);
+
+/*
+ * Reboot system call: for obvious reasons only root may call it,
+ * and even root needs to set up some magic numbers in the registers
+ * so that some mistake won't make this reboot the whole machine.
+ * You can also set the meaning of the ctrl-alt-del-key here.
+ *
+ * reboot doesn't sync: do that yourself before calling this.
+ */
+SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd,
+ void __user *, arg)
+{
+ struct pid_namespace *pid_ns = task_active_pid_ns(current);
+ char buffer[256];
+ int ret = 0;
+
+ /* We only trust the superuser with rebooting the system. */
+ if (!ns_capable(pid_ns->user_ns, CAP_SYS_BOOT))
+ return -EPERM;
+
+ /* For safety, we require "magic" arguments. */
+ if (magic1 != LINUX_REBOOT_MAGIC1 ||
+ (magic2 != LINUX_REBOOT_MAGIC2 &&
+ magic2 != LINUX_REBOOT_MAGIC2A &&
+ magic2 != LINUX_REBOOT_MAGIC2B &&
+ magic2 != LINUX_REBOOT_MAGIC2C))
+ return -EINVAL;
+
+ /*
+ * If pid namespaces are enabled and the current task is in a child
+ * pid_namespace, the command is handled by reboot_pid_ns() which will
+ * call do_exit().
+ */
+ ret = reboot_pid_ns(pid_ns, cmd);
+ if (ret)
+ return ret;
+
+ /* Instead of trying to make the power_off code look like
+ * halt when pm_power_off is not set do it the easy way.
+ */
+ if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !pm_power_off)
+ cmd = LINUX_REBOOT_CMD_HALT;
+
+ mutex_lock(&reboot_mutex);
+ switch (cmd) {
+ case LINUX_REBOOT_CMD_RESTART:
+ kernel_restart(NULL);
+ break;
+
+ case LINUX_REBOOT_CMD_CAD_ON:
+ C_A_D = 1;
+ break;
+
+ case LINUX_REBOOT_CMD_CAD_OFF:
+ C_A_D = 0;
+ break;
+
+ case LINUX_REBOOT_CMD_HALT:
+ kernel_halt();
+ do_exit(0);
+ panic("cannot halt");
+
+ case LINUX_REBOOT_CMD_POWER_OFF:
+ kernel_power_off();
+ do_exit(0);
+ break;
+
+ case LINUX_REBOOT_CMD_RESTART2:
+ if (strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1) < 0) {
+ ret = -EFAULT;
+ break;
+ }
+ buffer[sizeof(buffer) - 1] = '\0';
+
+ kernel_restart(buffer);
+ break;
+
+#ifdef CONFIG_KEXEC
+ case LINUX_REBOOT_CMD_KEXEC:
+ ret = kernel_kexec();
+ break;
+#endif
+
+#ifdef CONFIG_HIBERNATION
+ case LINUX_REBOOT_CMD_SW_SUSPEND:
+ ret = hibernate();
+ break;
+#endif
+
+ default:
+ ret = -EINVAL;
+ break;
+ }
+ mutex_unlock(&reboot_mutex);
+ return ret;
+}
+
+static void deferred_cad(struct work_struct *dummy)
+{
+ kernel_restart(NULL);
+}
+
+/*
+ * This function gets called by ctrl-alt-del - ie the keyboard interrupt.
+ * As it's called within an interrupt, it may NOT sync: the only choice
+ * is whether to reboot at once, or just ignore the ctrl-alt-del.
+ */
+void ctrl_alt_del(void)
+{
+ static DECLARE_WORK(cad_work, deferred_cad);
+
+ if (C_A_D)
+ schedule_work(&cad_work);
+ else
+ kill_cad_pid(SIGINT, 1);
+}
+
+char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff";
+
+static int __orderly_poweroff(bool force)
+{
+ char **argv;
+ static char *envp[] = {
+ "HOME=/",
+ "PATH=/sbin:/bin:/usr/sbin:/usr/bin",
+ NULL
+ };
+ int ret;
+
+ argv = argv_split(GFP_KERNEL, poweroff_cmd, NULL);
+ if (argv) {
+ ret = call_usermodehelper(argv[0], argv, envp, UMH_WAIT_EXEC);
+ argv_free(argv);
+ } else {
+ printk(KERN_WARNING "%s failed to allocate memory for \"%s\"\n",
+ __func__, poweroff_cmd);
+ ret = -ENOMEM;
+ }
+
+ if (ret && force) {
+ printk(KERN_WARNING "Failed to start orderly shutdown: "
+ "forcing the issue\n");
+ /*
+ * I guess this should try to kick off some daemon to sync and
+ * poweroff asap. Or not even bother syncing if we're doing an
+ * emergency shutdown?
+ */
+ emergency_sync();
+ kernel_power_off();
+ }
+
+ return ret;
+}
+
+static bool poweroff_force;
+
+static void poweroff_work_func(struct work_struct *work)
+{
+ __orderly_poweroff(poweroff_force);
+}
+
+static DECLARE_WORK(poweroff_work, poweroff_work_func);
+
+/**
+ * orderly_poweroff - Trigger an orderly system poweroff
+ * @force: force poweroff if command execution fails
+ *
+ * This may be called from any context to trigger a system shutdown.
+ * If the orderly shutdown fails, it will force an immediate shutdown.
+ */
+int orderly_poweroff(bool force)
+{
+ if (force) /* do not override the pending "true" */
+ poweroff_force = true;
+ schedule_work(&poweroff_work);
+ return 0;
+}
+EXPORT_SYMBOL_GPL(orderly_poweroff);