[RFC PATCH v7 15/23] entry/idle: Add a common function for activites during idle entry/exit

[Julien Desfossez]

From: "Joel Fernandes (Google)" <j...@joelfernandes.org>

Currently only RCU hooks for idle entry/exit are called. In later
patches, kernel-entry protection functionality will be added.

Signed-off-by: Joel Fernandes (Google) <j...@joelfernandes.org>
---
 include/linux/entry-common.h | 16 ++++++++++++++++
 kernel/sched/idle.c          | 17 +++++++++--------
 2 files changed, 25 insertions(+), 8 deletions(-)

diff --git a/include/linux/entry-common.h b/include/linux/entry-common.h
index efebbffcd5cc..2ea0e09b00d5 100644
--- a/include/linux/entry-common.h
+++ b/include/linux/entry-common.h
@@ -369,4 +369,20 @@ void irqentry_exit_cond_resched(void);
  */
 void noinstr irqentry_exit(struct pt_regs *regs, irqentry_state_t state);
 
+/**
+ * generic_idle_enter - Called during entry into idle for housekeeping.
+ */
+static inline void generic_idle_enter(void)
+{
+       rcu_idle_enter();
+}
+
+/**
+ * generic_idle_enter - Called when exiting idle for housekeeping.
+ */
+static inline void generic_idle_exit(void)
+{
+       rcu_idle_exit();
+}
+
 #endif
diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c
index 9c5637d866fd..269de55086c1 100644
--- a/kernel/sched/idle.c
+++ b/kernel/sched/idle.c
@@ -8,6 +8,7 @@
  */
 #include "sched.h"
 
+#include <linux/entry-common.h>
 #include <trace/events/power.h>
 
 /* Linker adds these: start and end of __cpuidle functions */
@@ -54,7 +55,7 @@ __setup("hlt", cpu_idle_nopoll_setup);
 
 static noinline int __cpuidle cpu_idle_poll(void)
 {
-       rcu_idle_enter();
+       generic_idle_enter();
        trace_cpu_idle_rcuidle(0, smp_processor_id());
        local_irq_enable();
        stop_critical_timings();
@@ -64,7 +65,7 @@ static noinline int __cpuidle cpu_idle_poll(void)
                cpu_relax();
        start_critical_timings();
        trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, smp_processor_id());
-       rcu_idle_exit();
+       generic_idle_exit();
 
        return 1;
 }
@@ -158,7 +159,7 @@ static void cpuidle_idle_call(void)
 
        if (cpuidle_not_available(drv, dev)) {
                tick_nohz_idle_stop_tick();
-               rcu_idle_enter();
+               generic_idle_enter();
 
                default_idle_call();
                goto exit_idle;
@@ -178,13 +179,13 @@ static void cpuidle_idle_call(void)
                u64 max_latency_ns;
 
                if (idle_should_enter_s2idle()) {
-                       rcu_idle_enter();
+                       generic_idle_enter();
 
                        entered_state = call_cpuidle_s2idle(drv, dev);
                        if (entered_state > 0)
                                goto exit_idle;
 
-                       rcu_idle_exit();
+                       generic_idle_exit();
 
                        max_latency_ns = U64_MAX;
                } else {
@@ -192,7 +193,7 @@ static void cpuidle_idle_call(void)
                }
 
                tick_nohz_idle_stop_tick();
-               rcu_idle_enter();
+               generic_idle_enter();
 
                next_state = cpuidle_find_deepest_state(drv, dev, 
max_latency_ns);
                call_cpuidle(drv, dev, next_state);
@@ -209,7 +210,7 @@ static void cpuidle_idle_call(void)
                else
                        tick_nohz_idle_retain_tick();
 
-               rcu_idle_enter();
+               generic_idle_enter();
 
                entered_state = call_cpuidle(drv, dev, next_state);
                /*
@@ -227,7 +228,7 @@ static void cpuidle_idle_call(void)
        if (WARN_ON_ONCE(irqs_disabled()))
                local_irq_enable();
 
-       rcu_idle_exit();
+       generic_idle_exit();
 }
 
 /*
-- 
2.17.1