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SubjectRe: [PATCH v3] checkpatch: add warning for avoiding .L prefix symbols in assembly files
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On Sun, 2021-01-24 at 00:34 +0530, Aditya Srivastava wrote:
> 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>

Acked-by: Joe Perches <joe@perches.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)$/);
>  
>


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