[PATCH v3] kselftests/damon: add support for cases where debugfs cannot be read

[Gautam]

The kernel is in lockdown mode when secureboot is enabled and hence
debugfs cannot be used. Add support for this and other general cases 
where debugfs cannot be read and communicate the same to the user before
running tests.

Signed-off-by: Gautam <gautammenghani201@xxxxxxxxx>
---
Changes in v2:
1. Modify the error message to account for general cases.
2. Change the return code so that the test is skipped.

Changes in v3:
1. Change the name of variable holding the error message.

 tools/testing/selftests/damon/_chk_dependency.sh | 10 ++++++++++
 1 file changed, 10 insertions(+)
 mode change 100644 => 100755 tools/testing/selftests/damon/_chk_dependency.sh

diff --git a/tools/testing/selftests/damon/_chk_dependency.sh b/tools/testing/selftests/damon/_chk_dependency.sh
old mode 100644
new mode 100755
index 0189db81550b..0328ac0b5a5e
--- a/tools/testing/selftests/damon/_chk_dependency.sh
+++ b/tools/testing/selftests/damon/_chk_dependency.sh
@@ -26,3 +26,13 @@ do
 		exit 1
 	fi
 done
+
+permission_error="Operation not permitted"
+for f in attrs target_ids monitor_on
+do
+	status=$( cat "$DBGFS/$f" 2>&1 )
+	if [ "${status#*$permission_error}" != "$status" ]; then
+		echo "Permission for reading $DBGFS/$f denied; maybe secureboot enabled?"
+		exit $ksft_skip
+	fi
+done
-- 
2.36.1