powerpc/powernv: Query firmware for count cache flush settings

BugLink: https://bugs.launchpad.net/bugs/1830176

commit 99d54754 upstream.

Look for fw-features properties to determine the appropriate settings
for the count cache flush, and then call the generic powerpc code to
set it up based on the security feature flags.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Juerg Haefliger <juergh@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

arch/powerpc/platforms/powernv/setup.c

@@ -77,6 +77,12 @@ static void init_fw_feat_flags(struct device_node *np)
 	if (fw_feature_is("enabled", "fw-count-cache-disabled", np))
 		security_ftr_set(SEC_FTR_COUNT_CACHE_DISABLED);
 
+	if (fw_feature_is("enabled", "fw-count-cache-flush-bcctr2,0,0", np))
+		security_ftr_set(SEC_FTR_BCCTR_FLUSH_ASSIST);
+
+	if (fw_feature_is("enabled", "needs-count-cache-flush-on-context-switch", np))
+		security_ftr_set(SEC_FTR_FLUSH_COUNT_CACHE);
+
 	/*
 	 * The features below are enabled by default, so we instead look to see
 	 * if firmware has *disabled* them, and clear them if so.
@@ -123,6 +129,7 @@ static void pnv_setup_rfi_flush(void)
 		  security_ftr_enabled(SEC_FTR_L1D_FLUSH_HV));
 
 	setup_rfi_flush(type, enable);
+	setup_count_cache_flush();
 }
 
 static void __init pnv_setup_arch(void)