Add a little selftest that validates all combinations.
Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org>
---
arch/Kconfig | 6 ++++++
kernel/jump_label.c | 39 ++++++++++++++++++++++++++++++++++++++-
2 files changed, 44 insertions(+), 1 deletion(-)
--- 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 JUMP_LABEL_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
--- a/kernel/jump_label.c
+++ b/kernel/jump_label.c
@@ -482,4 +482,41 @@ static void jump_label_update(struct sta
__jump_label_update(key, entry, stop);
}
-#endif
+#ifdef CONFIG_JUMP_LABEL_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 /* JUMP_LABEL_SELFTEST */
+
+#endif /* HAVE_JUMP_LABEL */
--
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