arm64: cpufeature: Pass capability structure to ->enable callback

From: Will Deacon <will.deacon@arm.com>

commit 0a0d111d upstream.

In order to invoke the CPU capability ->matches callback from the ->enable
callback for applying local-CPU workarounds, we need a handle on the
capability structure.

This patch passes a pointer to the capability structure to the ->enable
callback.
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Mark Rutland <mark.rutland@arm.com> [v4.9 backport]
Tested-by: Greg Hackmann <ghackmann@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

arch/arm64/kernel/cpufeature.c

@@ -1058,7 +1058,7 @@ void __init enable_cpu_capabilities(const struct arm64_cpu_capabilities *caps)
 			 * uses an IPI, giving us a PSTATE that disappears when
 			 * we return.
 			 */
-			stop_machine(caps->enable, NULL, cpu_online_mask);
+			stop_machine(caps->enable, (void *)caps, cpu_online_mask);
 }
 
 /*
@@ -1115,7 +1115,7 @@ verify_local_cpu_features(const struct arm64_cpu_capabilities *caps_list)
 			cpu_die_early();
 		}
 		if (caps->enable)
-			caps->enable(NULL);
+			caps->enable((void *)caps);
 	}
 }