selftests/resctrl: Extend CPU vendor detection

Currently, the resctrl_tests only has a function to detect AMD vendor.
Since when the Intel Sub-NUMA Clustering feature is enabled,
Intel CMT and MBM counters may not be accurate,
the resctrl_tests also need a function to detect Intel vendor.
And in the future, resctrl_tests will need a function to detect different
vendors, such as Arm.

Extend the function to detect Intel vendor as well. Also,
this function can be easily extended to detect other vendors.

Signed-off-by: Shaopeng Tan <[e-mail]>
Reviewed-by: Reinette Chatre <[e-mail]>
Reviewed-by: Shuah Khan <[e-mail]>
Signed-off-by: Shuah Khan <[e-mail]>

tools/testing/selftests/resctrl/cat_test.c

···
 
 	return show_cache_info(sum_llc_perf_miss, no_of_bits, param->span / 64,
 			       MAX_DIFF, MAX_DIFF_PERCENT, NUM_OF_RUNS,
-			       !is_amd, false);
+			       get_vendor() == ARCH_INTEL, false);
 }
 
 void cat_test_cleanup(void)

tools/testing/selftests/resctrl/resctrl.h

···
 #define L3_MON_PATH		"/sys/fs/resctrl/info/L3_MON"
 #define L3_MON_FEATURES_PATH	"/sys/fs/resctrl/info/L3_MON/mon_features"
 
+#define ARCH_INTEL     1
+#define ARCH_AMD       2
+
 #define PARENT_EXIT(err_msg)			\
 	do {					\
 		perror(err_msg);		\
···
 extern pid_t bm_pid, ppid;
 
 extern char llc_occup_path[1024];
-extern bool is_amd;
 
+int get_vendor(void);
 bool check_resctrlfs_support(void);
 int filter_dmesg(void);
 int remount_resctrlfs(bool mum_resctrlfs);

tools/testing/selftests/resctrl/resctrl_tests.c

···
 #define BENCHMARK_ARGS		64
 #define BENCHMARK_ARG_SIZE	64
 
-bool is_amd;
-
-void detect_amd(void)
+static int detect_vendor(void)
 {
 	FILE *inf = fopen("/proc/cpuinfo", "r");
+	int vendor_id = 0;
+	char *s = NULL;
 	char *res;
 
 	if (!inf)
-		return;
+		return vendor_id;
 
 	res = fgrep(inf, "vendor_id");
 
-	if (res) {
-		char *s = strchr(res, ':');
+	if (res)
+		s = strchr(res, ':');
 
-		is_amd = s && !strcmp(s, ": AuthenticAMD\n");
-		free(res);
-	}
+	if (s && !strcmp(s, ": GenuineIntel\n"))
+		vendor_id = ARCH_INTEL;
+	else if (s && !strcmp(s, ": AuthenticAMD\n"))
+		vendor_id = ARCH_AMD;
+
 	fclose(inf);
+	free(res);
+	return vendor_id;
+}
+
+int get_vendor(void)
+{
+	static int vendor = -1;
+
+	if (vendor == -1)
+		vendor = detect_vendor();
+	if (vendor == 0)
+		ksft_print_msg("Can not get vendor info...\n");
+
+	return vendor;
 }
 
 static void cmd_help(void)
···
 	if (geteuid() != 0)
 		return ksft_exit_fail_msg("Not running as root, abort testing.\n");
 
-	/* Detect AMD vendor */
-	detect_amd();
-
 	if (has_ben) {
 		/* Extract benchmark command from command line. */
 		for (i = ben_ind; i < argc; i++) {
···
 
 	ksft_set_plan(tests ? : 4);
 
-	if (!is_amd && mbm_test)
+	if ((get_vendor() == ARCH_INTEL) && mbm_test)
 		run_mbm_test(has_ben, benchmark_cmd, span, cpu_no, bw_report);
 
-	if (!is_amd && mba_test)
+	if ((get_vendor() == ARCH_INTEL) && mba_test)
 		run_mba_test(has_ben, benchmark_cmd, span, cpu_no, bw_report);
 
 	if (cmt_test)

tools/testing/selftests/resctrl/resctrlfs.c

···
 	char phys_pkg_path[1024];
 	FILE *fp;
 
-	if (is_amd)
+	if (get_vendor() == ARCH_AMD)
 		sprintf(phys_pkg_path, "%s%d/cache/index3/id",
 			PHYS_ID_PATH, cpu_no);
 	else