// 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); }