The core idle loop now takes care of it. However a few things need checking:
- Invocation of cpuidle_idle_call() in pseries_lpar_idle() happened through arch_cpu_idle() and was therefore always preceded by a call to ppc64_runlatch_off(). To preserve this property now that cpuidle_idle_call() is invoked directly from core code, a call to ppc64_runlatch_off() has been added to idle_loop_prolog() in platforms/pseries/processor_idle.c.
- Similarly, cpuidle_idle_call() was followed by ppc64_runlatch_off() so a call to the later has been added to idle_loop_epilog().
- And since arch_cpu_idle() always made sure to re-enable IRQs if they were not enabled, this is now done in idle_loop_epilog() as well.
The above was made in order to keep the execution flow close to the original. I don't know if that was strictly necessary. Someone well aquainted with the platform details might find some room for possible optimizations.
Signed-off-by: Nicolas Pitre nico@linaro.org --- arch/powerpc/platforms/pseries/processor_idle.c | 5 ++++ arch/powerpc/platforms/pseries/setup.c | 34 ++++++++++--------------- 2 files changed, 19 insertions(+), 20 deletions(-)
diff --git a/arch/powerpc/platforms/pseries/processor_idle.c b/arch/powerpc/platforms/pseries/processor_idle.c index a166e38bd6..72ddfe3d2f 100644 --- a/arch/powerpc/platforms/pseries/processor_idle.c +++ b/arch/powerpc/platforms/pseries/processor_idle.c @@ -33,6 +33,7 @@ static struct cpuidle_state *cpuidle_state_table;
static inline void idle_loop_prolog(unsigned long *in_purr) { + ppc64_runlatch_off(); *in_purr = mfspr(SPRN_PURR); /* * Indicate to the HV that we are idle. Now would be @@ -49,6 +50,10 @@ static inline void idle_loop_epilog(unsigned long in_purr) wait_cycles += mfspr(SPRN_PURR) - in_purr; get_lppaca()->wait_state_cycles = cpu_to_be64(wait_cycles); get_lppaca()->idle = 0; + + if (irqs_disabled()) + local_irq_enable(); + ppc64_runlatch_on(); }
static int snooze_loop(struct cpuidle_device *dev, diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c index c1f1908587..7604c19d54 100644 --- a/arch/powerpc/platforms/pseries/setup.c +++ b/arch/powerpc/platforms/pseries/setup.c @@ -39,7 +39,6 @@ #include <linux/irq.h> #include <linux/seq_file.h> #include <linux/root_dev.h> -#include <linux/cpuidle.h> #include <linux/of.h> #include <linux/kexec.h>
@@ -356,29 +355,24 @@ early_initcall(alloc_dispatch_log_kmem_cache);
static void pseries_lpar_idle(void) { - /* This would call on the cpuidle framework, and the back-end pseries - * driver to go to idle states + /* + * Default handler to go into low thread priority and possibly + * low power mode by cedeing processor to hypervisor */ - if (cpuidle_idle_call()) { - /* On error, execute default handler - * to go into low thread priority and possibly - * low power mode by cedeing processor to hypervisor - */
- /* Indicate to hypervisor that we are idle. */ - get_lppaca()->idle = 1; + /* Indicate to hypervisor that we are idle. */ + get_lppaca()->idle = 1;
- /* - * Yield the processor to the hypervisor. We return if - * an external interrupt occurs (which are driven prior - * to returning here) or if a prod occurs from another - * processor. When returning here, external interrupts - * are enabled. - */ - cede_processor(); + /* + * Yield the processor to the hypervisor. We return if + * an external interrupt occurs (which are driven prior + * to returning here) or if a prod occurs from another + * processor. When returning here, external interrupts + * are enabled. + */ + cede_processor();
- get_lppaca()->idle = 0; - } + get_lppaca()->idle = 0; }
/*