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From:   "Joel Fernandes (Google)" <joel@joelfernandes.org>
To:     linux-kernel@vger.kernel.org
Cc:     "Joel Fernandes (Google)" <joel@joelfernandes.org>,
        Aaron Lu <aaron.lwe@gmail.com>,
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        Christian Brauner <christian.brauner@ubuntu.com>
Subject: [PATCH RFC 05/12] entry/idle: Enter and exit kernel protection during idle entry and exit
Date:   Fri, 14 Aug 2020 23:19:01 -0400
Message-Id: <20200815031908.1015049-6-joel@joelfernandes.org>
In-Reply-To: <20200815031908.1015049-1-joel@joelfernandes.org>
References: <20200815031908.1015049-1-joel@joelfernandes.org>
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Make use of the generic_idle_{enter,exit} helper function added in
earlier patches to enter and exit kernel protection.

On exiting idle, protection will be reenabled.

Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
---
 include/linux/entry-common.h | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/include/linux/entry-common.h b/include/linux/entry-common.h
index 2ea0e09b00d5..c833f2fda542 100644
--- a/include/linux/entry-common.h
+++ b/include/linux/entry-common.h
@@ -374,6 +374,9 @@ void noinstr irqentry_exit(struct pt_regs *regs, irqentry_state_t state);
  */
 static inline void generic_idle_enter(void)
 {
+	/* Entering idle ends the protected kernel region. */
+	sched_core_unsafe_exit();
+
 	rcu_idle_enter();
 }
 
@@ -383,6 +386,9 @@ static inline void generic_idle_enter(void)
 static inline void generic_idle_exit(void)
 {
 	rcu_idle_exit();
+
+	/* Exiting idle (re)starts the protected kernel region. */
+	sched_core_unsafe_enter();
 }
 
 #endif
-- 
2.28.0.220.ged08abb693-goog