1 /*
2 * Copyright (C) 1996-2000 Russell King - Converted to ARM.
3 * Original Copyright (C) 1995 Linus Torvalds
4 *
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.
8 */
9 #include <linux/cpu.h>
10 #include <linux/delay.h>
11 #include <linux/reboot.h>
12
13 #include <asm/cacheflush.h>
14 #include <asm/idmap.h>
15 #include <asm/virt.h>
16
17 #include "reboot.h"
18
19 typedef void (*phys_reset_t)(unsigned long, bool);
20
21 /*
22 * Function pointers to optional machine specific functions
23 */
24 void (*arm_pm_restart)(enum reboot_mode reboot_mode, const char *cmd);
25 void (*pm_power_off)(void);
26 EXPORT_SYMBOL(pm_power_off);
27
28 /*
29 * A temporary stack to use for CPU reset. This is static so that we
30 * don't clobber it with the identity mapping. When running with this
31 * stack, any references to the current task *will not work* so you
32 * should really do as little as possible before jumping to your reset
33 * code.
34 */
35 static u64 soft_restart_stack[16];
36
__soft_restart(void * addr)37 static void __soft_restart(void *addr)
38 {
39 phys_reset_t phys_reset;
40
41 /* Take out a flat memory mapping. */
42 setup_mm_for_reboot();
43
44 /* Clean and invalidate caches */
45 flush_cache_all();
46
47 /* Turn off caching */
48 cpu_proc_fin();
49
50 /* Push out any further dirty data, and ensure cache is empty */
51 flush_cache_all();
52
53 /* Switch to the identity mapping. */
54 phys_reset = (phys_reset_t)virt_to_idmap(cpu_reset);
55
56 /* original stub should be restored by kvm */
57 phys_reset((unsigned long)addr, is_hyp_mode_available());
58
59 /* Should never get here. */
60 BUG();
61 }
62
_soft_restart(unsigned long addr,bool disable_l2)63 void _soft_restart(unsigned long addr, bool disable_l2)
64 {
65 u64 *stack = soft_restart_stack + ARRAY_SIZE(soft_restart_stack);
66
67 /* Disable interrupts first */
68 raw_local_irq_disable();
69 local_fiq_disable();
70
71 /* Disable the L2 if we're the last man standing. */
72 if (disable_l2)
73 outer_disable();
74
75 /* Change to the new stack and continue with the reset. */
76 call_with_stack(__soft_restart, (void *)addr, (void *)stack);
77
78 /* Should never get here. */
79 BUG();
80 }
81
soft_restart(unsigned long addr)82 void soft_restart(unsigned long addr)
83 {
84 _soft_restart(addr, num_online_cpus() == 1);
85 }
86
87 /*
88 * Called by kexec, immediately prior to machine_kexec().
89 *
90 * This must completely disable all secondary CPUs; simply causing those CPUs
91 * to execute e.g. a RAM-based pin loop is not sufficient. This allows the
92 * kexec'd kernel to use any and all RAM as it sees fit, without having to
93 * avoid any code or data used by any SW CPU pin loop. The CPU hotplug
94 * functionality embodied in disable_nonboot_cpus() to achieve this.
95 */
machine_shutdown(void)96 void machine_shutdown(void)
97 {
98 disable_nonboot_cpus();
99 }
100
101 /*
102 * Halting simply requires that the secondary CPUs stop performing any
103 * activity (executing tasks, handling interrupts). smp_send_stop()
104 * achieves this.
105 */
machine_halt(void)106 void machine_halt(void)
107 {
108 local_irq_disable();
109 smp_send_stop();
110 while (1);
111 }
112
113 /*
114 * Power-off simply requires that the secondary CPUs stop performing any
115 * activity (executing tasks, handling interrupts). smp_send_stop()
116 * achieves this. When the system power is turned off, it will take all CPUs
117 * with it.
118 */
machine_power_off(void)119 void machine_power_off(void)
120 {
121 local_irq_disable();
122 smp_send_stop();
123
124 if (pm_power_off)
125 pm_power_off();
126 }
127
128 /*
129 * Restart requires that the secondary CPUs stop performing any activity
130 * while the primary CPU resets the system. Systems with a single CPU can
131 * use soft_restart() as their machine descriptor's .restart hook, since that
132 * will cause the only available CPU to reset. Systems with multiple CPUs must
133 * provide a HW restart implementation, to ensure that all CPUs reset at once.
134 * This is required so that any code running after reset on the primary CPU
135 * doesn't have to co-ordinate with other CPUs to ensure they aren't still
136 * executing pre-reset code, and using RAM that the primary CPU's code wishes
137 * to use. Implementing such co-ordination would be essentially impossible.
138 */
machine_restart(char * cmd)139 void machine_restart(char *cmd)
140 {
141 local_irq_disable();
142 smp_send_stop();
143
144 if (arm_pm_restart)
145 arm_pm_restart(reboot_mode, cmd);
146 else
147 do_kernel_restart(cmd);
148
149 /* Give a grace period for failure to restart of 1s */
150 mdelay(1000);
151
152 /* Whoops - the platform was unable to reboot. Tell the user! */
153 printk("Reboot failed -- System halted\n");
154 while (1);
155 }
156
