tools/power turbostat: Provide better debug messages for failed capabilities accesses

turbostat reports some capabilities access errors and not others.  Provide
the same debug message for all errors.

[lenb: remove extra quotes]

Cc: David Arcari <[email protected]>
Signed-off-by: Prarit Bhargava <[email protected]>
Signed-off-by: Len Brown <[email protected]>

Author: prarit

tools/power/x86/turbostat/turbostat.8

@@ -340,7 +340,7 @@ starts a new interval.
 must be run as root.
 Alternatively, non-root users can be enabled to run turbostat this way:
 
-# setcap cap_sys_admin,cap_sys_rawio,cap_sys_nice=+ep ./turbostat
+# setcap cap_sys_admin,cap_sys_rawio,cap_sys_nice=+ep path/to/turbostat
 
 # chmod +r /dev/cpu/*/msr
 

tools/power/x86/turbostat/turbostat.c

@@ -670,7 +670,8 @@ static int perf_instr_count_open(int cpu_num)
 	/* counter for cpu_num, including user + kernel and all processes */
 	fd = perf_event_open(&pea, -1, cpu_num, -1, 0);
 	if (fd == -1) {
-		warn("cpu%d: perf instruction counter", cpu_num);
+		warnx("capget(CAP_PERFMON) failed, try \"# setcap cap_sys_admin=ep %s\"",
+		      progname);
 		BIC_NOT_PRESENT(BIC_IPC);
 	}
 
@@ -3502,9 +3503,6 @@ void msr_sum_record(void)
 /*
  * set_my_sched_priority(pri)
  * return previous
- *
- * if non-root, do this:
- * # /sbin/setcap cap_sys_rawio,cap_sys_nice=+ep /usr/bin/turbostat
  */
 int set_my_sched_priority(int priority)
 {
@@ -3518,7 +3516,8 @@ int set_my_sched_priority(int priority)
 
 	retval = setpriority(PRIO_PROCESS, 0, priority);
 	if (retval)
-		err(retval, "setpriority(%d)", priority);
+		errx(retval, "capget(CAP_SYS_NICE) failed,try \"# setcap cap_sys_nice=ep %s\"",
+		     progname);
 
 	errno = 0;
 	retval = getpriority(PRIO_PROCESS, 0);
@@ -5476,7 +5475,8 @@ void print_dev_latency(void)
 
 	fd = open(path, O_RDONLY);
 	if (fd < 0) {
-		warn("fopen %s\n", path);
+		warnx("capget(CAP_SYS_ADMIN) failed, try \"# setcap cap_sys_admin=ep %s\"",
+		      progname);
 		return;
 	}