perf: Don't use 4 bytes as a default instruction breakpoint length

4 bytes is fine as a default access for data breakpoints. But
instruction breakpoints should take the native pointer length,
otherwise we get a -EINVAL in x86-64.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Prasad <prasad@linux.vnet.ibm.com>
Cc: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Jason Wessel <jason.wessel@windriver.com>

tools/perf/util/parse-events.c

@@ -602,8 +602,15 @@ parse_breakpoint_event(const char **strp, struct perf_event_attr *attr)
 			return EVT_FAILED;
 	}
 
-	/* We should find a nice way to override the access type */
+	/*
+	 * We should find a nice way to override the access length
+	 * Provide some defaults for now
+	 */
+	if (attr->bp_type == HW_BREAKPOINT_X)
+		attr->bp_len = sizeof(long);
+	else
 		attr->bp_len = HW_BREAKPOINT_LEN_4;
+
 	attr->type = PERF_TYPE_BREAKPOINT;
 
 	return EVT_HANDLED;