libcpumf: Detect PMU named pai_ext

Add a check to detect Processor Activity Instrumentation (PAI)
Extension 1 facility unit.

Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>

libcpumf/libcpumf_example.c

@@ -85,5 +85,6 @@ int main(void)
 	}
 
 	printf("PAI NNPA support %d\n", libcpumf_have_pai_nnpa());
+	printf("PAI EXTENSION support %d\n", libcpumf_have_pai_ext());
 	return EXIT_SUCCESS;
 }

libcpumf/libcpumf_support.c

@@ -147,6 +147,13 @@ bool libcpumf_have_pai_crypto(void)
 	return (stat(S390_SYSFS_PAI_CRYPTO, &statbuf) == -1) ? false : true;
 }
 
+bool libcpumf_have_pai_ext(void)
+{
+	struct stat statbuf;
+
+	return (stat(S390_SYSFS_PAI_EXT, &statbuf) == -1) ? false : true;
+}
+
 bool libcpumf_have_pai_nnpa(void)
 {
 	struct stat statbuf;