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

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Message-ID: <14707ab9-1872-4f8c-3ed8-e77b663c3adb@gmail.com>
Date:   Wed, 20 Jan 2021 18:23:16 +0530
From:   Aditya <yashsri421@...il.com>
To:     Joe Perches <joe@...ches.com>, linux-kernel@...r.kernel.org
Cc:     lukas.bulwahn@...il.com, dwaipayanray1@...il.com,
        broonie@...nel.org, linux-kernel-mentees@...ts.linuxfoundation.org,
        clang-built-linux@...glegroups.com
Subject: Re: [PATCH] checkpatch: add warning for avoiding .L prefix symbols in
 assembly files

On 20/1/21 2:51 pm, Joe Perches wrote:
> On Wed, 2021-01-20 at 12:55 +0530, Aditya Srivastava wrote:
>> 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 a warning on finding the usage of '.L' symbols
>> in '.S' files, if it lies within SYM_*_START/END annotation pair.
> 
> I believe this needs a test for $file as it won't work well on
> patches as the SYM_*_START/END may not be in the patch context.
> 
Okay.

> Also, is this supposed to work for local labels like '.L<foo>:'?
> I don't think a warning should be generated for those.
> 
Yes, currently it will generate warning for all symbols which start
with .L and have non- white character symbol following it, if it is
lying within SYM_*_START/END annotation pair.

Should I reduce the check to \.L_\S+ instead? (please note "_"
following ".L")
Pardon me, I'm not good with assembly :/

Thanks
Aditya