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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 1996-2000 Russell King - Converted to ARM.
* Original Copyright (C) 1995 Linus Torvalds
*/
#include <linux/cpu.h>
#include <linux/delay.h>
#include <linux/reboot.h>
#include <asm/cacheflush.h>
#include <asm/idmap.h>
#include <asm/virt.h>
#include "reboot.h"
typedef void (*phys_reset_t)(unsigned long, bool);
/*
* Function pointers to optional machine specific functions
*/
void (*pm_power_off)(void);
EXPORT_SYMBOL(pm_power_off);
/*
* A temporary stack to use for CPU reset. This is static so that we
* don't clobber it with the identity mapping. When running with this
* stack, any references to the current task *will not work* so you
* should really do as little as possible before jumping to your reset
* code.
*/
static u64 soft_restart_stack[16];
static void __soft_restart(void *addr)
{
phys_reset_t phys_reset;
/* Take out a flat memory mapping. */
setup_mm_for_reboot();
/* Clean and invalidate caches */
flush_cache_all();
/* Turn off caching */
cpu_proc_fin();
/* Push out any further dirty data, and ensure cache is empty */
flush_cache_all();
/* Switch to the identity mapping. */
phys_reset = (phys_reset_t)virt_to_idmap(cpu_reset);
/* original stub should be restored by kvm */
phys_reset((unsigned long)addr, is_hyp_mode_available());
/* Should never get here. */
BUG();
}
void _soft_restart(unsigned long addr, bool disable_l2)
{
u64 *stack = soft_restart_stack + ARRAY_SIZE(soft_restart_stack);
/* Disable interrupts first */
raw_local_irq_disable();
local_fiq_disable();
/* Disable the L2 if we're the last man standing. */
if (disable_l2)
outer_disable();
/* Change to the new stack and continue with the reset. */
call_with_stack(__soft_restart, (void *)addr, (void *)stack);
/* Should never get here. */
BUG();
}
void soft_restart(unsigned long addr)
{
_soft_restart(addr, num_online_cpus() == 1);
}
/*
* Called by kexec, immediately prior to machine_kexec().
*
* This must completely disable all secondary CPUs; simply causing those CPUs
* to execute e.g. a RAM-based pin loop is not sufficient. This allows the
* kexec'd kernel to use any and all RAM as it sees fit, without having to
* avoid any code or data used by any SW CPU pin loop. The CPU hotplug
* functionality embodied in smp_shutdown_nonboot_cpus() to achieve this.
*/
void machine_shutdown(void)
{
smp_shutdown_nonboot_cpus(reboot_cpu);
}
/*
* Halting simply requires that the secondary CPUs stop performing any
* activity (executing tasks, handling interrupts). smp_send_stop()
* achieves this.
*/
void machine_halt(void)
{
local_irq_disable();
smp_send_stop();
while (1);
}
/*
* Power-off simply requires that the secondary CPUs stop performing any
* activity (executing tasks, handling interrupts). smp_send_stop()
* achieves this. When the system power is turned off, it will take all CPUs
* with it.
*/
void machine_power_off(void)
{
local_irq_disable();
smp_send_stop();
if (pm_power_off)
pm_power_off();
}
/*
* Restart requires that the secondary CPUs stop performing any activity
* while the primary CPU resets the system. Systems with a single CPU can
* use soft_restart() as their machine descriptor's .restart hook, since that
* will cause the only available CPU to reset. Systems with multiple CPUs must
* provide a HW restart implementation, to ensure that all CPUs reset at once.
* This is required so that any code running after reset on the primary CPU
* doesn't have to co-ordinate with other CPUs to ensure they aren't still
* executing pre-reset code, and using RAM that the primary CPU's code wishes
* to use. Implementing such co-ordination would be essentially impossible.
*/
void machine_restart(char *cmd)
{
local_irq_disable();
smp_send_stop();
do_kernel_restart(cmd);
/* Give a grace period for failure to restart of 1s */
mdelay(1000);
/* Whoops - the platform was unable to reboot. Tell the user! */
printk("Reboot failed -- System halted\n");
while (1);
}
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