[Linux-kernel-mentees] [PATCH] checkpatch: add warning for avoiding .L prefix symbols in assembly files

[Aditya Srivastava]

Local symbols prefixed with '.L' do not emit symbol table entries, as
they have special meaning for the assembler.

'.L' prefixed symbols can be used within a code region, but should be
avoided for denoting a range of code via 'SYM_*_START/END' annotations.

Add a new check to emit warning on finding the usage of '.L' symbols
in '.S' files.

Suggested-by: Mark Brown <broonie at kernel.org>
Link: https://lore.kernel.org/lkml/20210112210154.GI4646@sirena.org.uk/
Signed-off-by: Aditya Srivastava <yashsri421 at gmail.com>
---
 scripts/checkpatch.pl | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 7030c4d6d126..87d96a039e64 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -3590,6 +3590,12 @@ sub process {
 			}
 		}
 
+# check for .L prefix local symbols in .S files
+		if ($realfile =~ /\.S$/ && $line =~ /\.L\S+/) {
+			WARN("AVOID_L_PREFIX",
+			     "Avoid using '.L' prefixed local symbol names for denoting a range of code via 'SYM_*_START/END' annotations; see Documentation/asm-annotations.rst\n" . $herecurr);
+		}
+
 # check we are in a valid source file C or perl if not then ignore this hunk
 		next if ($realfile !~ /\.(h|c|pl|dtsi|dts)$/);
 
-- 
2.17.1