diff options
Diffstat (limited to 'kernel/cpu')
-rw-r--r-- | kernel/cpu/Makefile | 1 | ||||
-rw-r--r-- | kernel/cpu/idle.c | 107 |
2 files changed, 108 insertions, 0 deletions
diff --git a/kernel/cpu/Makefile b/kernel/cpu/Makefile new file mode 100644 index 000000000000..59ab052ef7a0 --- /dev/null +++ b/kernel/cpu/Makefile @@ -0,0 +1 @@ +obj-y = idle.o diff --git a/kernel/cpu/idle.c b/kernel/cpu/idle.c new file mode 100644 index 000000000000..168cf407a254 --- /dev/null +++ b/kernel/cpu/idle.c @@ -0,0 +1,107 @@ +/* + * Generic entry point for the idle threads + */ +#include <linux/sched.h> +#include <linux/cpu.h> +#include <linux/tick.h> +#include <linux/mm.h> + +#include <asm/tlb.h> + +#include <trace/events/power.h> + +static int __read_mostly cpu_idle_force_poll; + +void cpu_idle_poll_ctrl(bool enable) +{ + if (enable) { + cpu_idle_force_poll++; + } else { + cpu_idle_force_poll--; + WARN_ON_ONCE(cpu_idle_force_poll < 0); + } +} + +#ifdef CONFIG_GENERIC_IDLE_POLL_SETUP +static int __init cpu_idle_poll_setup(char *__unused) +{ + cpu_idle_force_poll = 1; + return 1; +} +__setup("nohlt", cpu_idle_poll_setup); + +static int __init cpu_idle_nopoll_setup(char *__unused) +{ + cpu_idle_force_poll = 0; + return 1; +} +__setup("hlt", cpu_idle_nopoll_setup); +#endif + +static inline int cpu_idle_poll(void) +{ + trace_cpu_idle_rcuidle(0, smp_processor_id()); + local_irq_enable(); + while (!need_resched()) + cpu_relax(); + trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, smp_processor_id()); + return 1; +} + +/* Weak implementations for optional arch specific functions */ +void __weak arch_cpu_idle_prepare(void) { } +void __weak arch_cpu_idle_enter(void) { } +void __weak arch_cpu_idle_exit(void) { } +void __weak arch_cpu_idle_dead(void) { } +void __weak arch_cpu_idle(void) +{ + cpu_idle_force_poll = 1; +} + +/* + * Generic idle loop implementation + */ +static void cpu_idle_loop(void) +{ + while (1) { + tick_nohz_idle_enter(); + + while (!need_resched()) { + check_pgt_cache(); + rmb(); + + if (cpu_is_offline(smp_processor_id())) + arch_cpu_idle_dead(); + + local_irq_disable(); + arch_cpu_idle_enter(); + + if (cpu_idle_force_poll) { + cpu_idle_poll(); + } else { + current_clr_polling(); + if (!need_resched()) { + stop_critical_timings(); + rcu_idle_enter(); + arch_cpu_idle(); + WARN_ON_ONCE(irqs_disabled()); + rcu_idle_exit(); + start_critical_timings(); + } else { + local_irq_enable(); + } + current_set_polling(); + } + arch_cpu_idle_exit(); + } + tick_nohz_idle_exit(); + schedule_preempt_disabled(); + } +} + +void cpu_startup_entry(enum cpuhp_state state) +{ + current_set_polling(); + arch_cpu_idle_prepare(); + cpu_idle_loop(); +} |