[tip:smp/hotplug] sh: Use generic idle loop

tip-bot for Thomas Gleixner
2013-04-08T20:43:31Z

Commit-ID: dc775dd886618a1ea6f092bfb3ddc78660aa1a19
Gitweb: http://git.kernel.org/tip/dc775dd886618a1ea6f092bfb3ddc78660aa1a19
Author: Thomas Gleixner <tglx@linutronix.de>
AuthorDate: Thu, 21 Mar 2013 22:49:59 +0100
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitDate: Mon, 8 Apr 2013 17:39:28 +0200

sh: Use generic idle loop

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Reviewed-by: Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: Magnus Damm <magnus.damm@gmail.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Link: http://lkml.kernel.org/r/20130321215235.216323644@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
arch/sh/Kconfig | 2 +
arch/sh/kernel/idle.c | 101 ++++++--------------------------------------------
arch/sh/kernel/smp.c | 2 +-
3 files changed, 14 insertions(+), 91 deletions(-)

diff --git a/arch/sh/Kconfig b/arch/sh/Kconfig
index 5e85963..853cbc9 100644
--- a/arch/sh/Kconfig
+++ b/arch/sh/Kconfig
@@ -33,6 +33,8 @@ config SUPERH
select GENERIC_ATOMIC64
select GENERIC_IRQ_SHOW
select GENERIC_SMP_IDLE_THREAD
+ select GENERIC_IDLE_LOOP
+ select GENERIC_IDLE_POLL_SETUP
select GENERIC_CLOCKEVENTS
select GENERIC_CMOS_UPDATE if SH_SH03 || SH_DREAMCAST
select GENERIC_STRNCPY_FROM_USER
diff --git a/arch/sh/kernel/idle.c b/arch/sh/kernel/idle.c
index 3d5a1b3..2ea4483 100644
--- a/arch/sh/kernel/idle.c
+++ b/arch/sh/kernel/idle.c
@@ -24,98 +24,24 @@

static void (*sh_idle)(void);

-static int hlt_counter;
-
-static int __init nohlt_setup(char *__unused)
-{
- hlt_counter = 1;
- return 1;
-}
-__setup("nohlt", nohlt_setup);
-
-static int __init hlt_setup(char *__unused)
-{
- hlt_counter = 0;
- return 1;
-}
-__setup("hlt", hlt_setup);
-
-static inline int hlt_works(void)
-{
- return !hlt_counter;
-}
-
-/*
- * On SMP it's slightly faster (but much more power-consuming!)
- * to poll the ->work.need_resched flag instead of waiting for the
- * cross-CPU IPI to arrive. Use this option with caution.
- */
-static void poll_idle(void)
+void default_idle(void)
{
+ set_bl_bit();
local_irq_enable();
- while (!need_resched())
- cpu_relax();
+ /* Isn't this racy ? */
+ cpu_sleep();
+ clear_bl_bit();
}

-void default_idle(void)
+void arch_cpu_idle_dead(void)
{
- if (hlt_works()) {
- clear_thread_flag(TIF_POLLING_NRFLAG);
- smp_mb__after_clear_bit();
-
- set_bl_bit();
- if (!need_resched()) {
- local_irq_enable();
- cpu_sleep();
- } else
- local_irq_enable();
-
- set_thread_flag(TIF_POLLING_NRFLAG);
- clear_bl_bit();
- } else
- poll_idle();
+ play_dead();
}

-/*
- * The idle thread. There's no useful work to be done, so just try to conserve
- * power and have a low exit latency (ie sit in a loop waiting for somebody to
- * say that they'd like to reschedule)
- */
-void cpu_idle(void)
+void arch_cpu_idle(void)
{
- unsigned int cpu = smp_processor_id();
-
- set_thread_flag(TIF_POLLING_NRFLAG);
-
- /* endless idle loop with no priority at all */
- while (1) {
- tick_nohz_idle_enter();
- rcu_idle_enter();
-
- while (!need_resched()) {
- check_pgt_cache();
- rmb();
-
- if (cpu_is_offline(cpu))
- play_dead();
-
- local_irq_disable();
- /* Don't trace irqs off for idle */
- stop_critical_timings();
- if (cpuidle_idle_call())
- sh_idle();
- /*
- * Sanity check to ensure that sh_idle() returns
- * with IRQs enabled
- */
- WARN_ON(irqs_disabled());
- start_critical_timings();
- }
-
- rcu_idle_exit();
- tick_nohz_idle_exit();
- schedule_preempt_disabled();
- }
+ if (cpuidle_idle_call())
+ sh_idle();
}

void __init select_idle_routine(void)
@@ -123,13 +49,8 @@ void __init select_idle_routine(void)
/*
* If a platform has set its own idle routine, leave it alone.
*/
- if (sh_idle)
- return;
-
- if (hlt_works())
+ if (!sh_idle)
sh_idle = default_idle;
- else
- sh_idle = poll_idle;
}

void stop_this_cpu(void *unused)
diff --git a/arch/sh/kernel/smp.c b/arch/sh/kernel/smp.c
index 2062aa8..4569645 100644
--- a/arch/sh/kernel/smp.c
+++ b/arch/sh/kernel/smp.c
@@ -203,7 +203,7 @@ asmlinkage void __cpuinit start_secondary(void)
set_cpu_online(cpu, true);
per_cpu(cpu_state, cpu) = CPU_ONLINE;

- cpu_idle();
+ cpu_startup_entry(CPUHP_ONLINE);
}

extern struct {