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Commit 1987c947 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

locking/static_keys: Add selftest 



Add a little selftest that validates all combinations.

Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 11276d53

arch/Kconfig

+6 −0
Original line number Diff line number Diff line
@@ -71,6 +71,12 @@ config JUMP_LABEL 
	 ( On 32-bit x86, the necessary options added to the compiler

	   flags may increase the size of the kernel slightly. )



config STATIC_KEYS_SELFTEST

	bool "Static key selftest"

	depends on JUMP_LABEL

	help

	  Boot time self-test of the branch patching code.



config OPTPROBES

	def_bool y

	depends on KPROBES && HAVE_OPTPROBES

kernel/jump_label.c

+38 −1
Original line number Diff line number Diff line
@@ -482,4 +482,41 @@ static void jump_label_update(struct static_key *key) 
		__jump_label_update(key, entry, stop);

}



#endif
 
#ifdef CONFIG_STATIC_KEYS_SELFTEST

static DEFINE_STATIC_KEY_TRUE(sk_true);

static DEFINE_STATIC_KEY_FALSE(sk_false);



static __init int jump_label_test(void)

{

	int i;



	for (i = 0; i < 2; i++) {

		WARN_ON(static_key_enabled(&sk_true.key) != true);

		WARN_ON(static_key_enabled(&sk_false.key) != false);



		WARN_ON(!static_branch_likely(&sk_true));

		WARN_ON(!static_branch_unlikely(&sk_true));

		WARN_ON(static_branch_likely(&sk_false));

		WARN_ON(static_branch_unlikely(&sk_false));



		static_branch_disable(&sk_true);

		static_branch_enable(&sk_false);



		WARN_ON(static_key_enabled(&sk_true.key) == true);

		WARN_ON(static_key_enabled(&sk_false.key) == false);



		WARN_ON(static_branch_likely(&sk_true));

		WARN_ON(static_branch_unlikely(&sk_true));

		WARN_ON(!static_branch_likely(&sk_false));

		WARN_ON(!static_branch_unlikely(&sk_false));



		static_branch_enable(&sk_true);

		static_branch_disable(&sk_false);

	}



	return 0;

}

late_initcall(jump_label_test);

#endif /* STATIC_KEYS_SELFTEST */



#endif /* HAVE_JUMP_LABEL */