diff options
| -rw-r--r-- | arch/Kconfig | 3 | ||||
| -rw-r--r-- | include/linux/cpu.h | 8 | ||||
| -rw-r--r-- | kernel/cpu/idle.c | 105 |
3 files changed, 116 insertions, 0 deletions
diff --git a/arch/Kconfig b/arch/Kconfig index 1455579791ec..a699f3767be4 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -216,6 +216,9 @@ config USE_GENERIC_SMP_HELPERS config GENERIC_SMP_IDLE_THREAD bool +config GENERIC_IDLE_LOOP + bool + # Select if arch init_task initializer is different to init/init_task.c config ARCH_INIT_TASK bool diff --git a/include/linux/cpu.h b/include/linux/cpu.h index 7419e30c55fb..c6f6e0839b61 100644 --- a/include/linux/cpu.h +++ b/include/linux/cpu.h @@ -220,4 +220,12 @@ enum cpuhp_state { void cpu_startup_entry(enum cpuhp_state state); void cpu_idle(void); +void cpu_idle_poll_ctrl(bool enable); + +void arch_cpu_idle(void); +void arch_cpu_idle_prepare(void); +void arch_cpu_idle_enter(void); +void arch_cpu_idle_exit(void); +void arch_cpu_idle_dead(void); + #endif /* _LINUX_CPU_H_ */ diff --git a/kernel/cpu/idle.c b/kernel/cpu/idle.c index 1908f00e0e98..54c320383934 100644 --- a/kernel/cpu/idle.c +++ b/kernel/cpu/idle.c @@ -3,8 +3,113 @@ */ #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> + +#ifndef CONFIG_GENERIC_IDLE_LOOP void cpu_startup_entry(enum cpuhp_state state) { cpu_idle(); } +#else + +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(); +} +#endif |