powerpc/pseries: Query hypervisor for count cache flush settings

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

commit ba72dc17 upstream.

Use the existing hypercall 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/include/asm/hvcall.h

@@ -316,10 +316,12 @@
 #define H_CPU_CHAR_BRANCH_HINTS_HONORED	(1ull << 58) // IBM bit 5
 #define H_CPU_CHAR_THREAD_RECONFIG_CTRL	(1ull << 57) // IBM bit 6
 #define H_CPU_CHAR_COUNT_CACHE_DISABLED	(1ull << 56) // IBM bit 7
+#define H_CPU_CHAR_BCCTR_FLUSH_ASSIST	(1ull << 54) // IBM bit 9
 
 #define H_CPU_BEHAV_FAVOUR_SECURITY	(1ull << 63) // IBM bit 0
 #define H_CPU_BEHAV_L1D_FLUSH_PR	(1ull << 62) // IBM bit 1
 #define H_CPU_BEHAV_BNDS_CHK_SPEC_BAR	(1ull << 61) // IBM bit 2
+#define H_CPU_BEHAV_FLUSH_COUNT_CACHE	(1ull << 58) // IBM bit 5
 
 #ifndef __ASSEMBLY__
 #include <linux/types.h>

arch/powerpc/platforms/pseries/setup.c

@@ -524,6 +524,12 @@ static void init_cpu_char_feature_flags(struct h_cpu_char_result *result)
 	if (result->character & H_CPU_CHAR_COUNT_CACHE_DISABLED)
 		security_ftr_set(SEC_FTR_COUNT_CACHE_DISABLED);
 
+	if (result->character & H_CPU_CHAR_BCCTR_FLUSH_ASSIST)
+		security_ftr_set(SEC_FTR_BCCTR_FLUSH_ASSIST);
+
+	if (result->behaviour & H_CPU_BEHAV_FLUSH_COUNT_CACHE)
+		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.
@@ -574,6 +580,7 @@ void pseries_setup_rfi_flush(void)
 		 security_ftr_enabled(SEC_FTR_L1D_FLUSH_PR);
 
 	setup_rfi_flush(types, enable);
+	setup_count_cache_flush();
 }
 
 static void __init pSeries_setup_arch(void)