selftests: livepatch: add new ftrace helpers functions

Add new ftrace helpers functions cleanup_tracing, trace_function and
check_traced_functions.

Signed-off-by: Filipe Xavier <felipeaggger@gmail.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Joe Lawrence <joe.lawrence@redhat.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Tested-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20250324-ftrace-sftest-livepatch-v3-1-d9d7cc386c75@gmail.com
Signed-off-by: Petr Mladek <pmladek@suse.com>

diff --git a/tools/testing/selftests/livepatch/functions.sh b/tools/testing/selftests/livepatch/functions.sh
index e5d06fb402335d85959bafe099087effc6ddce12..f5d1915bc95b67d1b88be7128280dffad4feb8ef 100644 (file)
--- a/tools/testing/selftests/livepatch/functions.sh
+++ b/tools/testing/selftests/livepatch/functions.sh
@@ -10,6 +10,7 @@ SYSFS_KERNEL_DIR="/sys/kernel"
 SYSFS_KLP_DIR="$SYSFS_KERNEL_DIR/livepatch"
 SYSFS_DEBUG_DIR="$SYSFS_KERNEL_DIR/debug"
 SYSFS_KPROBES_DIR="$SYSFS_DEBUG_DIR/kprobes"
+SYSFS_TRACING_DIR="$SYSFS_DEBUG_DIR/tracing"
 
 # Kselftest framework requirement - SKIP code is 4
 ksft_skip=4
@@ -62,6 +63,9 @@ function push_config() {
                        awk -F'[: ]' '{print "file " $1 " line " $2 " " $4}')
        FTRACE_ENABLED=$(sysctl --values kernel.ftrace_enabled)
        KPROBE_ENABLED=$(cat "$SYSFS_KPROBES_DIR/enabled")
+       TRACING_ON=$(cat "$SYSFS_TRACING_DIR/tracing_on")
+       CURRENT_TRACER=$(cat "$SYSFS_TRACING_DIR/current_tracer")
+       FTRACE_FILTER=$(cat "$SYSFS_TRACING_DIR/set_ftrace_filter")
 }
 
 function pop_config() {
@@ -74,6 +78,17 @@ function pop_config() {
        if [[ -n "$KPROBE_ENABLED" ]]; then
                echo "$KPROBE_ENABLED" > "$SYSFS_KPROBES_DIR/enabled"
        fi
+       if [[ -n "$TRACING_ON" ]]; then
+               echo "$TRACING_ON" > "$SYSFS_TRACING_DIR/tracing_on"
+       fi
+       if [[ -n "$CURRENT_TRACER" ]]; then
+               echo "$CURRENT_TRACER" > "$SYSFS_TRACING_DIR/current_tracer"
+       fi
+       if [[ -n "$FTRACE_FILTER" ]]; then
+               echo "$FTRACE_FILTER" \
+                       | sed -e "/#### all functions enabled ####/d" \
+                       > "$SYSFS_TRACING_DIR/set_ftrace_filter"
+       fi
 }
 
 function set_dynamic_debug() {
@@ -351,3 +366,37 @@ function check_sysfs_value() {
                die "Unexpected value in $path: $expected_value vs. $value"
        fi
 }
+
+# cleanup_tracing() - stop and clean up function tracing
+function cleanup_tracing() {
+       echo 0 > "$SYSFS_TRACING_DIR/tracing_on"
+       echo "" > "$SYSFS_TRACING_DIR/set_ftrace_filter"
+       echo "nop" > "$SYSFS_TRACING_DIR/current_tracer"
+       echo "" > "$SYSFS_TRACING_DIR/trace"
+}
+
+# trace_function(function) - start tracing of a function
+#      function - to be traced function
+function trace_function() {
+       local function="$1"; shift
+
+       cleanup_tracing
+
+       echo "function" > "$SYSFS_TRACING_DIR/current_tracer"
+       echo "$function" > "$SYSFS_TRACING_DIR/set_ftrace_filter"
+       echo 1 > "$SYSFS_TRACING_DIR/tracing_on"
+}
+
+# check_traced_functions(functions...) - check whether each function appeared in the trace log
+#      functions - list of functions to be checked
+function check_traced_functions() {
+       local function
+
+       for function in "$@"; do
+               if ! grep -Fwq "$function" "$SYSFS_TRACING_DIR/trace" ; then
+                       die "Function ($function) did not appear in the trace"
+               fi
+       done
+
+       cleanup_tracing
+}