1 // SPDX-License-Identifier: GPL-2.0-only
3 * Copyright (C) 1996-2000 Russell King - Converted to ARM.
4 * Original Copyright (C) 1995 Linus Torvalds
7 #include <linux/delay.h>
8 #include <linux/reboot.h>
10 #include <asm/cacheflush.h>
11 #include <asm/idmap.h>
16 typedef void (*phys_reset_t)(unsigned long, bool);
19 * Function pointers to optional machine specific functions
21 void (*pm_power_off)(void);
22 EXPORT_SYMBOL(pm_power_off);
25 * A temporary stack to use for CPU reset. This is static so that we
26 * don't clobber it with the identity mapping. When running with this
27 * stack, any references to the current task *will not work* so you
28 * should really do as little as possible before jumping to your reset
31 static u64 soft_restart_stack[16];
33 static void __soft_restart(void *addr)
35 phys_reset_t phys_reset;
37 /* Take out a flat memory mapping. */
38 setup_mm_for_reboot();
40 /* Clean and invalidate caches */
43 /* Turn off caching */
46 /* Push out any further dirty data, and ensure cache is empty */
49 /* Switch to the identity mapping. */
50 phys_reset = (phys_reset_t)virt_to_idmap(cpu_reset);
52 /* original stub should be restored by kvm */
53 phys_reset((unsigned long)addr, is_hyp_mode_available());
55 /* Should never get here. */
59 void _soft_restart(unsigned long addr, bool disable_l2)
61 u64 *stack = soft_restart_stack + ARRAY_SIZE(soft_restart_stack);
63 /* Disable interrupts first */
64 raw_local_irq_disable();
67 /* Disable the L2 if we're the last man standing. */
71 /* Change to the new stack and continue with the reset. */
72 call_with_stack(__soft_restart, (void *)addr, (void *)stack);
74 /* Should never get here. */
78 void soft_restart(unsigned long addr)
80 _soft_restart(addr, num_online_cpus() == 1);
84 * Called by kexec, immediately prior to machine_kexec().
86 * This must completely disable all secondary CPUs; simply causing those CPUs
87 * to execute e.g. a RAM-based pin loop is not sufficient. This allows the
88 * kexec'd kernel to use any and all RAM as it sees fit, without having to
89 * avoid any code or data used by any SW CPU pin loop. The CPU hotplug
90 * functionality embodied in smp_shutdown_nonboot_cpus() to achieve this.
92 void machine_shutdown(void)
94 smp_shutdown_nonboot_cpus(reboot_cpu);
98 * Halting simply requires that the secondary CPUs stop performing any
99 * activity (executing tasks, handling interrupts). smp_send_stop()
102 void machine_halt(void)
110 * Power-off simply requires that the secondary CPUs stop performing any
111 * activity (executing tasks, handling interrupts). smp_send_stop()
112 * achieves this. When the system power is turned off, it will take all CPUs
115 void machine_power_off(void)
125 * Restart requires that the secondary CPUs stop performing any activity
126 * while the primary CPU resets the system. Systems with a single CPU can
127 * use soft_restart() as their machine descriptor's .restart hook, since that
128 * will cause the only available CPU to reset. Systems with multiple CPUs must
129 * provide a HW restart implementation, to ensure that all CPUs reset at once.
130 * This is required so that any code running after reset on the primary CPU
131 * doesn't have to co-ordinate with other CPUs to ensure they aren't still
132 * executing pre-reset code, and using RAM that the primary CPU's code wishes
133 * to use. Implementing such co-ordination would be essentially impossible.
135 void machine_restart(char *cmd)
140 do_kernel_restart(cmd);
142 /* Give a grace period for failure to restart of 1s */
145 /* Whoops - the platform was unable to reboot. Tell the user! */
146 printk("Reboot failed -- System halted\n");