selftests/tracing: Add basic test for trace_marker_raw file

Commit 64cf7d058a00 ("tracing: Have trace_marker use per-cpu data to read
user space") made an update that fixed both trace_marker and
trace_marker_raw. But the small difference made to trace_marker_raw had a
blatant bug in it that any basic testing would have uncovered.
Unfortunately, the self tests have tests for trace_marker but nothing for
trace_marker_raw which allowed the bug to get upstream.

Add basic selftests to test trace_marker_raw so that this doesn't happen
again.

Link: https://lore.kernel.org/r/20251014145149.3e3c1033@gandalf.local.home
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

diff --git a/tools/testing/selftests/ftrace/test.d/00basic/trace_marker_raw.tc b/tools/testing/selftests/ftrace/test.d/00basic/trace_marker_raw.tc
new file mode 100644 (file)
index 0000000..7daf729
--- /dev/null
+++ b/tools/testing/selftests/ftrace/test.d/00basic/trace_marker_raw.tc
@@ -0,0 +1,107 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# description: Basic tests on writing to trace_marker_raw
+# requires: trace_marker_raw
+# flags: instance
+
+is_little_endian() {
+       if lscpu | grep -q 'Little Endian'; then
+               echo 1;
+       else
+               echo 0;
+       fi
+}
+
+little=`is_little_endian`
+
+make_str() {
+       id=$1
+       cnt=$2
+
+       if [ $little -eq 1 ]; then
+               val=`printf "\\%03o\\%03o\\%03o\\%03o" \
+                       $(($id & 0xff)) \
+                       $((($id >> 8) & 0xff)) \
+                       $((($id >> 16) & 0xff)) \
+                       $((($id >> 24) & 0xff))`
+       else
+               val=`printf "\\%03o\\%03o\\%03o\\%03o" \
+                       $((($id >> 24) & 0xff)) \
+                       $((($id >> 16) & 0xff)) \
+                       $((($id >> 8) & 0xff)) \
+                       $(($id & 0xff))`
+       fi
+
+       data=`printf -- 'X%.0s' $(seq $cnt)`
+
+       printf "${val}${data}"
+}
+
+write_buffer() {
+       id=$1
+       size=$2
+
+       # write the string into the raw marker
+       make_str $id $size > trace_marker_raw
+}
+
+
+test_multiple_writes() {
+
+       # Write a bunch of data where the id is the count of
+       # data to write
+       for i in `seq 1 10` `seq 101 110` `seq 1001 1010`; do
+               write_buffer $i $i
+       done
+
+       # add a little buffer
+       echo stop > trace_marker
+
+       # Check to make sure the number of entries is the id (rounded up by 4)
+       awk '/.*: # [0-9a-f]* / {
+                       print;
+                       cnt = -1;
+                       for (i = 0; i < NF; i++) {
+                               # The counter is after the "#" marker
+                               if ( $i == "#" ) {
+                                       i++;
+                                       cnt = strtonum("0x" $i);
+                                       num = NF - (i + 1);
+                                       # The number of items is always rounded up by 4
+                                       cnt2 = int((cnt + 3) / 4) * 4;
+                                       if (cnt2 != num) {
+                                               exit 1;
+                                       }
+                                       break;
+                               }
+                       }
+               }
+       // { if (NR > 30) { exit 0; } } ' trace_pipe;
+}
+
+
+get_buffer_data_size() {
+       sed -ne 's/^.*data.*size:\([0-9][0-9]*\).*/\1/p' events/header_page
+}
+
+test_buffer() {
+
+       # The id must be four bytes, test that 3 bytes fails a write
+       if echo -n abc > ./trace_marker_raw ; then
+               echo "Too small of write expected to fail but did not"
+               exit_fail
+       fi
+
+       size=`get_buffer_data_size`
+       echo size = $size
+
+       # Now add a little more than what it can handle
+
+       if write_buffer 0xdeadbeef $size ; then
+               echo "Too big of write expected to fail but did not"
+               exit_fail
+       fi
+}
+
+test_buffer
+test_multiple_writes