selftests/powerpc: Skip security tests on older CPUs

Both these tests use PMU events that only work on newer CPUs, so skip
them on older CPUs.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200819015727.1977134-6-mpe@ellerman.id.au

tools/testing/selftests/powerpc/security/rfi_flush.c

@@ -89,6 +89,9 @@ int rfi_flush_test(void)
 
 	SKIP_IF(geteuid() != 0);
 
+	// The PMU event we use only works on Power7 or later
+	SKIP_IF(!have_hwcap(PPC_FEATURE_ARCH_2_06));
+
 	if (read_debugfs_file("powerpc/rfi_flush", &rfi_flush_org)) {
 		perror("Unable to read powerpc/rfi_flush debugfs file");
 		SKIP_IF(1);

tools/testing/selftests/powerpc/security/spectre_v2.c

@@ -134,6 +134,9 @@ int spectre_v2_test(void)
 	s64 miss_percent;
 	bool is_p9;
 
+	// The PMU events we use only work on Power8 or later
+	SKIP_IF(!have_hwcap2(PPC_FEATURE2_ARCH_2_07));
+
 	state = get_sysfs_state();
 	if (state == UNKNOWN) {
 		printf("Error: couldn't determine spectre_v2 mitigation state?\n");