arm64: kernel: Add cpufeature 'enable' callback

commit 1c0763037f1e1caef739e36e09c6d41ed7b61b2d upstream. This patch adds an 'enable()' callback to cpu capability/feature detection, allowing features that require some setup or configuration to get this opportunity once the feature has been detected. Acked-by: Catalin Marinas <[email protected]> Signed-off-by: James Morse <[email protected]> Signed-off-by: Will Deacon <[email protected]> Signed-off-by: David Brown <[email protected]>
carlitros900 · May 23, 2019 · d67ba78 · d67ba78
1 parent 33701a7
commit d67ba78
Show file tree

Hide file tree

Showing 2 changed files with 7 additions and 0 deletions.
diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h
@@ -34,6 +34,7 @@ struct arm64_cpu_capabilities {
 	const char *desc;
 	u16 capability;
 	bool (*matches)(const struct arm64_cpu_capabilities *);
+	void (*enable)(void);
 	union {
 		struct {	/* To be used for erratum handling only */
 			u32 midr_model;

diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
@@ -63,6 +63,12 @@ void check_cpu_capabilities(const struct arm64_cpu_capabilities *caps,
 			pr_info("%s %s\n", info, caps[i].desc);
 		cpus_set_cap(caps[i].capability);
 	}
+
+	/* second pass allows enable() to consider interacting capabilities */
+	for (i = 0; caps[i].desc; i++) {
+		if (cpus_have_cap(caps[i].capability) && caps[i].enable)
+			caps[i].enable();
+	}
 }
 
 void check_local_cpu_features(void)