[patch 06/34] arc: Use generic idle loop

Thomas Gleixner
2013-03-21T22:02:44Z

[-- Attachment #1: arc-use-generic-idle-loop.patch --]
[-- Type: text/plain, Size: 2346 bytes --]

The generic idle loop implements all functionality. Aside of that it
allows arc to implement the tsk_is_polling() functionality correctly,
despite the patently (now gone) comment in the original arc cpu_idle()
function:
/* Since we SLEEP in idle loop, TIF_POLLING_NRFLAG can't be set */
See kernel/cpu/idle.c

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Vineet Gupta <vgupta@synopsys.com>
---
arch/arc/Kconfig | 1 +
arch/arc/kernel/process.c | 27 +--------------------------
arch/arc/kernel/smp.c | 2 +-
3 files changed, 3 insertions(+), 27 deletions(-)

Index: linux-2.6/arch/arc/Kconfig
===================================================================
--- linux-2.6.orig/arch/arc/Kconfig
+++ linux-2.6/arch/arc/Kconfig
@@ -20,6 +20,7 @@ config ARC
select GENERIC_KERNEL_THREAD
select GENERIC_PENDING_IRQ if SMP
select GENERIC_SMP_IDLE_THREAD
+ select GENERIC_IDLE_LOOP
select HAVE_ARCH_KGDB
select HAVE_ARCH_TRACEHOOK
select HAVE_GENERIC_HARDIRQS
Index: linux-2.6/arch/arc/kernel/process.c
===================================================================
--- linux-2.6.orig/arch/arc/kernel/process.c
+++ linux-2.6/arch/arc/kernel/process.c
@@ -41,37 +41,12 @@ SYSCALL_DEFINE0(arc_gettls)
return task_thread_info(current)->thr_ptr;
}

-static inline void arch_idle(void)
+void arch_cpu_idle(void)
{
/* sleep, but enable all interrupts before committing */
__asm__("sleep 0x3");
}

-void cpu_idle(void)
-{
- /* Since we SLEEP in idle loop, TIF_POLLING_NRFLAG can't be set */
-
- /* endless idle loop with no priority at all */
- while (1) {
- tick_nohz_idle_enter();
- rcu_idle_enter();
-
-doze:
- local_irq_disable();
- if (!need_resched()) {
- arch_idle();
- goto doze;
- } else {
- local_irq_enable();
- }
-
- rcu_idle_exit();
- tick_nohz_idle_exit();
-
- schedule_preempt_disabled();
- }
-}
-
asmlinkage void ret_from_fork(void);

/* Layout of Child kernel mode stack as setup at the end of this function is
Index: linux-2.6/arch/arc/kernel/smp.c
===================================================================
--- linux-2.6.orig/arch/arc/kernel/smp.c
+++ linux-2.6/arch/arc/kernel/smp.c
@@ -141,7 +141,7 @@ void __cpuinit start_kernel_secondary(vo

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

/*