linux-kernel - Re: [PATCH v2 2/4] arm64/sysreg: Enforce whole word match for open/close tokens

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Message-ID: <36968527640d231882444ba7065317fe@kernel.org>
Date: Fri, 14 Mar 2025 07:40:36 +0000
From: Marc Zyngier <maz@...nel.org>
To: Will Deacon <will@...nel.org>
Cc: James Clark <james.clark@...aro.org>,
 linux-arm-kernel@...ts.infradead.org, robh@...nel.org, broonie@...nel.org,
 Catalin Marinas <catalin.marinas@....com>, Mark Rutland
 <mark.rutland@....com>, Oliver Upton <oliver.upton@...ux.dev>, Anshuman
 Khandual <anshuman.khandual@....com>, James Morse <james.morse@....com>,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 2/4] arm64/sysreg: Enforce whole word match for
 open/close tokens

On 2025-03-13 21:56, Will Deacon wrote:
> On Wed, Jan 15, 2025 at 04:25:56PM +0000, James Clark wrote:
>> Opening and closing tokens can also match on words with common 
>> prefixes
>> like "Endsysreg" vs "EndsysregFields". This could potentially make the
>> script go wrong in weird ways so make it fall through to the fatal
>> unhandled statement catcher if it doesn't fully match the current
>> block.
>> 
>> Closing ones also get expect_fields(1) to ensure nothing other than
>> whitespace follows.
>> 
>> Signed-off-by: James Clark <james.clark@...aro.org>
>> ---
>>  arch/arm64/tools/gen-sysreg.awk | 31 +++++++++++++++++--------------
>>  1 file changed, 17 insertions(+), 14 deletions(-)
>> 
>> diff --git a/arch/arm64/tools/gen-sysreg.awk 
>> b/arch/arm64/tools/gen-sysreg.awk
>> index 1a2afc9fdd42..f2a1732cb1f6 100755
>> --- a/arch/arm64/tools/gen-sysreg.awk
>> +++ b/arch/arm64/tools/gen-sysreg.awk
>> @@ -111,7 +111,7 @@ END {
>>  /^$/ { next }
>>  /^[\t ]*#/ { next }
>> 
>> -/^SysregFields/ && block_current() == "Root" {
>> +$1 == "SysregFields" && block_current() == "Root" {
> 
> Stylistic nit, but could you just do:
> 
> 	/^SysregFields$/ && block_current() == "Root" {
> 
> instead? That way the diff is smaller (well, same number of lines) and
> you avoid the ugly $1.

The code is trying to match the first field of a line such as:

SysregFields	ZCR_ELx

while you seem to try and match a SysregFields all alone on a line.

That being said, my perl-foo is sub-zero, so I may be very wrong myself.

         M.
-- 
Jazz is not dead. It just smells funny...