diff options
Diffstat (limited to 'arch/arm64/kernel/process.c')
| -rw-r--r-- | arch/arm64/kernel/process.c | 49 |
1 files changed, 40 insertions, 9 deletions
diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c index 6391485f342d..43b7c34f92cb 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -20,6 +20,7 @@ #include <stdarg.h> +#include <linux/compat.h> #include <linux/export.h> #include <linux/sched.h> #include <linux/kernel.h> @@ -113,32 +114,62 @@ void arch_cpu_idle_dead(void) } #endif +/* + * 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) { -#ifdef CONFIG_SMP - smp_send_stop(); -#endif + disable_nonboot_cpus(); } +/* + * Halting simply requires that the secondary CPUs stop performing any + * activity (executing tasks, handling interrupts). smp_send_stop() + * achieves this. + */ void machine_halt(void) { - machine_shutdown(); + 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) { - machine_shutdown(); + 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) { - machine_shutdown(); - /* Disable interrupts first */ local_irq_disable(); + smp_send_stop(); /* Now call the architecture specific reboot code. */ if (arm_pm_restart) @@ -205,7 +236,7 @@ void release_thread(struct task_struct *dead_task) int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src) { - fpsimd_save_state(¤t->thread.fpsimd_state); + fpsimd_preserve_current_state(); *dst = *src; return 0; } @@ -300,7 +331,7 @@ struct task_struct *__switch_to(struct task_struct *prev, * Complete any pending TLB or cache maintenance on this CPU in case * the thread migrates to a different CPU. */ - dsb(); + dsb(ish); /* the actual thread switch */ last = cpu_switch_to(prev, next); |