Commit-ID:  321a874a7ef85655e93b3206d0f36b4a6097f948
Gitweb:     https://git.kernel.org/tip/321a874a7ef85655e93b3206d0f36b4a6097f948
Author:     Thomas Gleixner <t...@linutronix.de>
AuthorDate: Sun, 25 Nov 2018 19:33:38 +0100
Committer:  Thomas Gleixner <t...@linutronix.de>
CommitDate: Wed, 28 Nov 2018 11:57:07 +0100

sched/smt: Expose sched_smt_present static key

Make the scheduler's 'sched_smt_present' static key globaly available, so
it can be used in the x86 speculation control code.

Provide a query function and a stub for the CONFIG_SMP=n case.

Signed-off-by: Thomas Gleixner <t...@linutronix.de>
Reviewed-by: Ingo Molnar <mi...@kernel.org>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Andy Lutomirski <l...@kernel.org>
Cc: Linus Torvalds <torva...@linux-foundation.org>
Cc: Jiri Kosina <jkos...@suse.cz>
Cc: Tom Lendacky <thomas.lenda...@amd.com>
Cc: Josh Poimboeuf <jpoim...@redhat.com>
Cc: Andrea Arcangeli <aarca...@redhat.com>
Cc: David Woodhouse <d...@amazon.co.uk>
Cc: Tim Chen <tim.c.c...@linux.intel.com>
Cc: Andi Kleen <a...@linux.intel.com>
Cc: Dave Hansen <dave.han...@intel.com>
Cc: Casey Schaufler <casey.schauf...@intel.com>
Cc: Asit Mallick <asit.k.mall...@intel.com>
Cc: Arjan van de Ven <ar...@linux.intel.com>
Cc: Jon Masters <j...@redhat.com>
Cc: Waiman Long <longman9...@gmail.com>
Cc: Greg KH <gre...@linuxfoundation.org>
Cc: Dave Stewart <david.c.stew...@intel.com>
Cc: Kees Cook <keesc...@chromium.org>
Cc: sta...@vger.kernel.org
Link: https://lkml.kernel.org/r/20181125185004.430168...@linutronix.de

---
 include/linux/sched/smt.h | 18 ++++++++++++++++++
 kernel/sched/sched.h      |  4 +---
 2 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/include/linux/sched/smt.h b/include/linux/sched/smt.h
new file mode 100644
index 000000000000..c9e0be514110
--- /dev/null
+++ b/include/linux/sched/smt.h
@@ -0,0 +1,18 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_SCHED_SMT_H
+#define _LINUX_SCHED_SMT_H
+
+#include <linux/static_key.h>
+
+#ifdef CONFIG_SCHED_SMT
+extern struct static_key_false sched_smt_present;
+
+static __always_inline bool sched_smt_active(void)
+{
+       return static_branch_likely(&sched_smt_present);
+}
+#else
+static inline bool sched_smt_active(void) { return false; }
+#endif
+
+#endif
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 618577fc9aa8..4e524ab589c9 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -23,6 +23,7 @@
 #include <linux/sched/prio.h>
 #include <linux/sched/rt.h>
 #include <linux/sched/signal.h>
+#include <linux/sched/smt.h>
 #include <linux/sched/stat.h>
 #include <linux/sched/sysctl.h>
 #include <linux/sched/task.h>
@@ -936,9 +937,6 @@ static inline int cpu_of(struct rq *rq)
 
 
 #ifdef CONFIG_SCHED_SMT
-
-extern struct static_key_false sched_smt_present;
-
 extern void __update_idle_core(struct rq *rq);
 
 static inline void update_idle_core(struct rq *rq)

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