cregit-Linux how code gets into the kernel

Release 4.11 arch/arm/kernel/reboot.c

Directory: arch/arm/kernel
/*
 *  Copyright (C) 1996-2000 Russell King - Converted to ARM.
 *  Original Copyright (C) 1995  Linus Torvalds
 * 
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#include <linux/cpu.h>
#include <linux/delay.h>
#include <linux/reboot.h>

#include <asm/cacheflush.h>
#include <asm/idmap.h>

#include "reboot.h"


typedef void (*phys_reset_t)(unsigned long);

/*
 * Function pointers to optional machine specific functions
 */

void (*arm_pm_restart)(enum reboot_mode reboot_mode, const char *cmd);

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); phys_reset((unsigned long)addr); /* Should never get here. */ BUG(); }

Contributors

PersonTokensPropCommitsCommitProp
Russell King5298.11%150.00%
Vitaly Andrianov11.89%150.00%
Total53100.00%2100.00%


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(); }

Contributors

PersonTokensPropCommitsCommitProp
Russell King60100.00%1100.00%
Total60100.00%1100.00%


void soft_restart(unsigned long addr) { _soft_restart(addr, num_online_cpus() == 1); }

Contributors

PersonTokensPropCommitsCommitProp
Russell King19100.00%1100.00%
Total19100.00%1100.00%

/* * 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 disable_nonboot_cpus() to achieve this. */
void machine_shutdown(void) { disable_nonboot_cpus(); }

Contributors

PersonTokensPropCommitsCommitProp
Russell King10100.00%1100.00%
Total10100.00%1100.00%

/* * 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); }

Contributors

PersonTokensPropCommitsCommitProp
Russell King18100.00%1100.00%
Total18100.00%1100.00%

/* * 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(); }

Contributors

PersonTokensPropCommitsCommitProp
Russell King20100.00%1100.00%
Total20100.00%1100.00%

/* * 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(); if (arm_pm_restart) arm_pm_restart(reboot_mode, cmd); else 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); }

Contributors

PersonTokensPropCommitsCommitProp
Russell King49100.00%1100.00%
Total49100.00%1100.00%


Overall Contributors

PersonTokensPropCommitsCommitProp
Russell King30199.67%150.00%
Vitaly Andrianov10.33%150.00%
Total302100.00%2100.00%
Directory: arch/arm/kernel
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