diff options
Diffstat (limited to 'arch/arm/kernel/reboot.c')
| -rw-r--r-- | arch/arm/kernel/reboot.c | 147 |
1 files changed, 147 insertions, 0 deletions
diff --git a/arch/arm/kernel/reboot.c b/arch/arm/kernel/reboot.c new file mode 100644 index 0000000000..3f0d5c3dae --- /dev/null +++ b/arch/arm/kernel/reboot.c @@ -0,0 +1,147 @@ +// 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 <asm/system_misc.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(); + do_kernel_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); +} |