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git.proxmox.com Git - mirror_ubuntu-zesty-kernel.git/blob - arch/arm/kernel/reboot.c
2 * Copyright (C) 1996-2000 Russell King - Converted to ARM.
3 * Original Copyright (C) 1995 Linus Torvalds
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
10 #include <linux/delay.h>
11 #include <linux/reboot.h>
13 #include <asm/cacheflush.h>
14 #include <asm/idmap.h>
18 typedef void (*phys_reset_t
)(unsigned long);
21 * Function pointers to optional machine specific functions
23 void (*arm_pm_restart
)(enum reboot_mode reboot_mode
, const char *cmd
);
24 void (*pm_power_off
)(void);
25 EXPORT_SYMBOL(pm_power_off
);
28 * A temporary stack to use for CPU reset. This is static so that we
29 * don't clobber it with the identity mapping. When running with this
30 * stack, any references to the current task *will not work* so you
31 * should really do as little as possible before jumping to your reset
34 static u64 soft_restart_stack
[16];
36 static void __soft_restart(void *addr
)
38 phys_reset_t phys_reset
;
40 /* Take out a flat memory mapping. */
41 setup_mm_for_reboot();
43 /* Clean and invalidate caches */
46 /* Turn off caching */
49 /* Push out any further dirty data, and ensure cache is empty */
52 /* Switch to the identity mapping. */
53 phys_reset
= (phys_reset_t
)(unsigned long)virt_to_idmap(cpu_reset
);
54 phys_reset((unsigned long)addr
);
56 /* Should never get here. */
60 void _soft_restart(unsigned long addr
, bool disable_l2
)
62 u64
*stack
= soft_restart_stack
+ ARRAY_SIZE(soft_restart_stack
);
64 /* Disable interrupts first */
65 raw_local_irq_disable();
68 /* Disable the L2 if we're the last man standing. */
72 /* Change to the new stack and continue with the reset. */
73 call_with_stack(__soft_restart
, (void *)addr
, (void *)stack
);
75 /* Should never get here. */
79 void soft_restart(unsigned long addr
)
81 _soft_restart(addr
, num_online_cpus() == 1);
85 * Called by kexec, immediately prior to machine_kexec().
87 * This must completely disable all secondary CPUs; simply causing those CPUs
88 * to execute e.g. a RAM-based pin loop is not sufficient. This allows the
89 * kexec'd kernel to use any and all RAM as it sees fit, without having to
90 * avoid any code or data used by any SW CPU pin loop. The CPU hotplug
91 * functionality embodied in disable_nonboot_cpus() to achieve this.
93 void machine_shutdown(void)
95 disable_nonboot_cpus();
99 * Halting simply requires that the secondary CPUs stop performing any
100 * activity (executing tasks, handling interrupts). smp_send_stop()
103 void machine_halt(void)
113 * Power-off simply requires that the secondary CPUs stop performing any
114 * activity (executing tasks, handling interrupts). smp_send_stop()
115 * achieves this. When the system power is turned off, it will take all CPUs
118 void machine_power_off(void)
128 * Restart requires that the secondary CPUs stop performing any activity
129 * while the primary CPU resets the system. Systems with a single CPU can
130 * use soft_restart() as their machine descriptor's .restart hook, since that
131 * will cause the only available CPU to reset. Systems with multiple CPUs must
132 * provide a HW restart implementation, to ensure that all CPUs reset at once.
133 * This is required so that any code running after reset on the primary CPU
134 * doesn't have to co-ordinate with other CPUs to ensure they aren't still
135 * executing pre-reset code, and using RAM that the primary CPU's code wishes
136 * to use. Implementing such co-ordination would be essentially impossible.
138 void machine_restart(char *cmd
)
144 arm_pm_restart(reboot_mode
, cmd
);
146 do_kernel_restart(cmd
);
148 /* Give a grace period for failure to restart of 1s */
151 /* Whoops - the platform was unable to reboot. Tell the user! */
152 printk("Reboot failed -- System halted\n");