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

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Date:   Fri, 22 Jan 2021 11:10:10 -0800
From:   Joe Perches <joe@...ches.com>
To:     Aditya <yashsri421@...il.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 Fri, 2021-01-22 at 18:48 +0530, Aditya wrote:
> On 21/1/21 12:13 am, Joe Perches wrote:
> > I believe the test should be:
> > 
> > 	if ($realfile =~ /\.S$/ &&
> > 	    $line =~ /^\+\s*SYM_[A-Z]+_(?:START|END)(?:_[A-Z_]+)?\s*\(\s*\.L/) {
> 
> Joe, with this regex, we won't be able to match
> "jmp  .L_restore
> SYM_FUNC_END(\name)"

I think that's not an issue.

> which was replaced in this patch in the discussion:
> https://groups.google.com/g/clang-built-linux/c/-drkmLgu-cU/m/phKe-Tb6CgAJ
> 
> Here, "jmp  .L_restore" was also replaced to fix the error.

Notice that this line was also replaced in the same patch:

 #ifdef CONFIG_PREEMPTION
-SYM_CODE_START_LOCAL_NOALIGN(.L_restore)
+SYM_CODE_START_LOCAL_NOALIGN(__thunk_restore)


> However, if this
> regex(/^\+\s*SYM_[A-Z]+_(?:START|END)(?:_[A-Z_]+)?\s*\(\s*\.L/) is
> correct, maybe we don't need to check for $file as we are now checking
> for just one line.
> 
> What do you think?

The test I wrote was complete, did not use $file and emits a
warning on the use of CODE_SYM_START_LOCAL_NOALIGN(.L_restore)

I think it's sufficient.