From: Aditya Srivastava <yashsri421@gmail.com>
To: joe@perches.com
Cc: yashsri421@gmail.com, lukas.bulwahn@gmail.com,
dwaipayanray1@gmail.com, broonie@kernel.org,
ndesaulniers@google.com, jpoimboe@redhat.com,
linux-kernel-mentees@lists.linuxfoundation.org,
clang-built-linux@googlegroups.com, linux-kernel@vger.kernel.org
Subject: [PATCH v3] checkpatch: add warning for avoiding .L prefix symbols in assembly files
Date: Sun, 24 Jan 2021 00:34:59 +0530 [thread overview]
Message-ID: <20210123190459.9701-1-yashsri421@gmail.com> (raw)
In-Reply-To: <f23f4003-0017-d52a-39b9-2737e60182bb@gmail.com>
objtool requires that all code must be contained in an ELF symbol.
Symbol names that have a '.L' prefix 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 a warning on finding the usage of '.L' symbols
for '.S' files, if it denotes range of code via SYM_*_START/END
annotation pair.
Suggested-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/lkml/20210112210154.GI4646@sirena.org.uk
Signed-off-by: Aditya Srivastava <yashsri421@gmail.com>
---
* Applies perfectly on next-20210122
Changes in v3:
- Modify regex for SYM_*_START/END pair
- remove check for arch/x86/entry/* and arch/x86/lib/*
- change 'Link:' in commit message to lkml
- Modify commit description accordingly
Changes in v2:
- Reduce the check to only SYM_*_START/END lines
- Reduce the check for only .S files in arch/x86/entry/* and arch/x86/lib/* as suggested by Josh and Nick
- Modify commit message
scripts/checkpatch.pl | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 7030c4d6d126..4a03326c87b6 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -3590,6 +3590,13 @@ sub process {
}
}
+# check for .L prefix local symbols in .S files
+ if ($realfile =~ /\.S$/ &&
+ $line =~ /^\+\s*(?:[A-Z]+_)?SYM_[A-Z]+_(?:START|END)(?:_[A-Z_]+)?\s*\(\s*\.L/) {
+ 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
next prev parent reply other threads:[~2021-01-23 19:07 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-20 7:25 [PATCH] checkpatch: add warning for avoiding .L prefix symbols in assembly files Aditya Srivastava
2021-01-20 9:21 ` Joe Perches
2021-01-20 12:53 ` Aditya
2021-01-20 18:43 ` Joe Perches
2021-01-20 18:57 ` Nick Desaulniers
2021-01-20 22:59 ` Josh Poimboeuf
2021-01-22 13:18 ` Aditya
2021-01-22 19:10 ` Joe Perches
2021-01-22 20:13 ` Aditya
2021-01-22 20:36 ` Fāng-ruì Sòng
2021-01-23 15:14 ` [PATCH v2] " Aditya Srivastava
2021-01-23 17:21 ` Joe Perches
2021-01-23 18:23 ` Aditya
2021-01-23 19:04 ` Aditya Srivastava [this message]
2021-01-23 21:01 ` [PATCH v3] " Joe Perches
2021-01-25 18:15 ` Nick Desaulniers
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