tools/power turbostat: Handle cap_get_proc() ENOSYS

Kernels configured with CONFIG_MULTIUSER=n have no cap_get_proc().
Check for ENOSYS to recognize this case, and continue on to
attempt to access the requested MSRs (such as temperature).

Signed-off-by: Calvin Owens <[email protected]>
Signed-off-by: Len Brown <[email protected]>

Author: jcalvinowens

tools/power/x86/turbostat/turbostat.c

@@ -6574,8 +6574,16 @@ int check_for_cap_sys_rawio(void)
 	int ret = 0;
 
 	caps = cap_get_proc();
-	if (caps == NULL)
+	if (caps == NULL) {
+		/*
+		 * CONFIG_MULTIUSER=n kernels have no cap_get_proc()
+		 * Allow them to continue and attempt to access MSRs
+		 */
+		if (errno == ENOSYS)
+			return 0;
+
 		return 1;
+	}
 
 	if (cap_get_flag(caps, CAP_SYS_RAWIO, CAP_EFFECTIVE, &cap_flag_value)) {
 		ret = 1;