From a1a04ec3c7c27a682473fd9beb2c996316a64649 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Thu, 21 Mar 2013 22:49:34 +0100 Subject: idle: Provide a generic entry point for the idle code For now this calls cpu_idle(), but in the long run we want to move the cpu bringup code to the core and therefor we add a state argument. Signed-off-by: Thomas Gleixner Cc: Linus Torvalds Cc: Rusty Russell Cc: Paul McKenney Cc: Peter Zijlstra Reviewed-by: Cc: Srivatsa S. Bhat Cc: Magnus Damm Link: http://lkml.kernel.org/r/20130321215233.583190032@linutronix.de Signed-off-by: Thomas Gleixner --- kernel/cpu/Makefile | 1 + kernel/cpu/idle.c | 10 ++++++++++ 2 files changed, 11 insertions(+) create mode 100644 kernel/cpu/Makefile create mode 100644 kernel/cpu/idle.c (limited to 'kernel/cpu') 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..1908f00e0e98 --- /dev/null +++ b/kernel/cpu/idle.c @@ -0,0 +1,10 @@ +/* + * Generic entry point for the idle threads + */ +#include +#include + +void cpu_startup_entry(enum cpuhp_state state) +{ + cpu_idle(); +} -- cgit v1.2.3 From d166991234347215dc23fc9dc15a63a83a1a54e1 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Thu, 21 Mar 2013 22:49:35 +0100 Subject: idle: Implement generic idle function All idle functions in arch/* are more or less the same, plus minus a few bugs and extra instrumentation, tickless support and other optional items. Implement a generic idle function which resembles the functionality found in arch/. Provide weak arch_cpu_idle_* functions which can be overridden by the architecture code if needed. Signed-off-by: Thomas Gleixner Cc: Linus Torvalds Cc: Rusty Russell Cc: Paul McKenney Cc: Peter Zijlstra Reviewed-by: Cc: Srivatsa S. Bhat Cc: Magnus Damm Link: http://lkml.kernel.org/r/20130321215233.646635455@linutronix.de Signed-off-by: Thomas Gleixner --- kernel/cpu/idle.c | 105 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 105 insertions(+) (limited to 'kernel/cpu') 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 #include +#include +#include +#include + +#include + +#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 -- cgit v1.2.3 From d190e8195b90bc1e65c494fe08e54e9e581bfd16 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Wed, 17 Apr 2013 10:33:13 +0200 Subject: idle: Remove GENERIC_IDLE_LOOP config switch All archs are converted over. Remove the config switch and the fallback code. Signed-off-by: Thomas Gleixner --- kernel/cpu/idle.c | 8 -------- 1 file changed, 8 deletions(-) (limited to 'kernel/cpu') diff --git a/kernel/cpu/idle.c b/kernel/cpu/idle.c index 54c320383934..168cf407a254 100644 --- a/kernel/cpu/idle.c +++ b/kernel/cpu/idle.c @@ -10,13 +10,6 @@ #include -#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) @@ -112,4 +105,3 @@ void cpu_startup_entry(enum cpuhp_state state) arch_cpu_idle_prepare(); cpu_idle_loop(); } -#endif -- cgit v1.2.3