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-rw-r--r--arch/Kconfig6
-rw-r--r--kernel/jump_label.c39
2 files changed, 44 insertions, 1 deletions
diff --git a/arch/Kconfig b/arch/Kconfig
index 8a8ea7110de8..a71cdbe2a04d 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -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
diff --git a/kernel/jump_label.c b/kernel/jump_label.c
index 8fd00d892286..f7dd15d537f9 100644
--- a/kernel/jump_label.c
+++ b/kernel/jump_label.c
@@ -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 */