perf tools: Allow r0x<HEX> event syntax

Add support to specify raw event with 'r0<HEX>' syntax within pmu term
syntax like:

  -e cpu/r0xdead/

It will be used to specify raw events in cases where they conflict with
real pmu terms, like 'read', which is valid raw event syntax, but also a
possible pmu term name as reported by Jin Yao.
Reported-by: Jin Yao <yao.jin@linux.intel.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Ian Rogers <irogers@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Richter <tmricht@linux.ibm.com>
Link: http://lore.kernel.org/lkml/20200725121959.1181869-1-jolsa@kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/Documentation/perf-list.txt

@@ -119,6 +119,7 @@ It's also possible to use pmu syntax:
 
  perf record -e r1a8 -a sleep 1
  perf record -e cpu/r1a8/ ...
+ perf record -e cpu/r0x1a8/ ...
 
 You should refer to the processor specific documentation for getting these
 details. Some of them are referenced in the SEE ALSO section below.

tools/perf/tests/parse-events.c

@@ -1766,6 +1766,11 @@ static struct evlist_test test__events_pmu[] = {
 		.check = test__checkevent_raw_pmu,
 		.id    = 4,
 	},
+	{
+		.name  = "software/r0x1a/",
+		.check = test__checkevent_raw_pmu,
+		.id    = 4,
+	},
 };
 
 struct terms_test {

tools/perf/util/parse-events.l

@@ -293,6 +293,7 @@ percore			{ return term(yyscanner, PARSE_EVENTS__TERM_TYPE_PERCORE); }
 aux-output		{ return term(yyscanner, PARSE_EVENTS__TERM_TYPE_AUX_OUTPUT); }
 aux-sample-size		{ return term(yyscanner, PARSE_EVENTS__TERM_TYPE_AUX_SAMPLE_SIZE); }
 r{num_raw_hex}		{ return raw(yyscanner); }
+r0x{num_raw_hex}	{ return raw(yyscanner); }
 ,			{ return ','; }
 "/"			{ BEGIN(INITIAL); return '/'; }
 {name_minus}		{ return str(yyscanner, PE_NAME); }