context_tracking: Take IRQ eqs entrypoints over RCU

The RCU dynticks counter is going to be merged into the context tracking
subsystem. Prepare with moving the IRQ extended quiescent states
entrypoints to context tracking. For now those are dumb redirection to
existing RCU calls.

[ paulmck: Apply Stephen Rothwell feedback from -next. ]
[ paulmck: Apply Nathan Chancellor feedback. ]

Acked-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com>
Cc: Uladzislau Rezki <uladzislau.rezki@sony.com>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Nicolas Saenz Julienne <nsaenz@kernel.org>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Xiongfeng Wang <wangxiongfeng2@huawei.com>
Cc: Yu Liao <liaoyu15@huawei.com>
Cc: Phil Auld <pauld@redhat.com>
Cc: Paul Gortmaker<paul.gortmaker@windriver.com>
Cc: Alex Belits <abelits@marvell.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Nicolas Saenz Julienne <nsaenzju@redhat.com>
Tested-by: Nicolas Saenz Julienne <nsaenzju@redhat.com>

1 files changed, 22 insertions, 2 deletions

diff --git a/kernel/context_tracking.c b/kernel/context_tracking.c
index c0b3798d4e94..72bd71a02c44 100644
--- a/kernel/context_tracking.c
+++ b/kernel/context_tracking.c
@@ -35,6 +35,26 @@ void ct_idle_exit(void)
 	rcu_idle_exit();
 }
 EXPORT_SYMBOL_GPL(ct_idle_exit);
+
+noinstr void ct_irq_enter(void)
+{
+	rcu_irq_enter();
+}
+
+noinstr void ct_irq_exit(void)
+{
+	rcu_irq_exit();
+}
+
+void ct_irq_enter_irqson(void)
+{
+	rcu_irq_enter_irqson();
+}
+
+void ct_irq_exit_irqson(void)
+{
+	rcu_irq_exit_irqson();
+}
 #endif /* #ifdef CONFIG_CONTEXT_TRACKING_IDLE */
 
 #ifdef CONFIG_CONTEXT_TRACKING_USER
@@ -90,7 +110,7 @@ void noinstr __ct_user_enter(enum ctx_state state)
 			 * At this stage, only low level arch entry code remains and
 			 * then we'll run in userspace. We can assume there won't be
 			 * any RCU read-side critical section until the next call to
-			 * user_exit() or rcu_irq_enter(). Let's remove RCU's dependency
+			 * user_exit() or ct_irq_enter(). Let's remove RCU's dependency
 			 * on the tick.
 			 */
 			if (state == CONTEXT_USER) {
@@ -136,7 +156,7 @@ void ct_user_enter(enum ctx_state state)
 	/*
 	 * Some contexts may involve an exception occuring in an irq,
 	 * leading to that nesting:
-	 * rcu_irq_enter() rcu_user_exit() rcu_user_exit() rcu_irq_exit()
+	 * ct_irq_enter() rcu_user_exit() rcu_user_exit() ct_irq_exit()
 	 * This would mess up the dyntick_nesting count though. And rcu_irq_*()
 	 * helpers are enough to protect RCU uses inside the exception. So
 	 * just return immediately if we detect we are in an IRQ.