perf parse-regs: Split parse_regs

The available registers for --int-regs and --user-regs may be different,
e.g. XMM registers.

Split parse_regs into two dedicated functions for --int-regs and
--user-regs respectively.

Modify the warning message. "--user-regs=?" should be applied to show
the available registers for --user-regs.

Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Tested-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Link: http://lkml.kernel.org/r/1557865174-56264-1-git-send-email-kan.liang@linux.intel.com
[ Changed docs as suggested by Ravi and agreed by Kan ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt
index 27b37624c376..de269430720a 100644
--- a/tools/perf/Documentation/perf-record.txt
+++ b/tools/perf/Documentation/perf-record.txt
@@ -406,7 +406,8 @@ symbolic names, e.g. on x86, ax, si. To list the available registers use
 --intr-regs=ax,bx. The list of register is architecture dependent.
 
 --user-regs::
-Capture user registers at sample time. Same arguments as -I.
+Similar to -I, but capture user registers at sample time. To list the available
+user registers use --user-regs=\?.
 
 --running-time::
 Record running and enabled time for read events (:S)