[PATCH v10 04/10] arm64/sysreg: Add a comment that the sysreg file should be sorted

[James Clark]

On 14/01/2025 6:16 pm, Rob Herring wrote:
> On Mon, Jan 13, 2025 at 10:49 AM Marc Zyngier <maz at kernel.org> wrote:
>>
>> On Mon, 13 Jan 2025 15:43:39 +0000,
>> James Clark <james.clark at linaro.org> wrote:
>>>
>>>
>>>
>>> On 12/01/2025 12:49 pm, Marc Zyngier wrote:
>>>> On Tue, 07 Jan 2025 11:32:41 +0000,
>>>> James Clark <james.clark at linaro.org> wrote:
>>>>>
>>>>> From: James Clark <james.clark at arm.com>
>>>>>
>>>>> There are a few entries particularly at the end of the file that aren't
>>>>> in order. To avoid confusion, add a comment that might help new entries
>>>>> to be added in the right place.
>>>>>
>>>>> Reviewed-by: Mark Brown <broonie at kernel.org>
>>>>> Signed-off-by: James Clark <james.clark at arm.com>
>>>>> Signed-off-by: James Clark <james.clark at linaro.org>
>>>>> ---
>>>>>    arch/arm64/tools/sysreg | 2 ++
>>>>>    1 file changed, 2 insertions(+)
>>>>>
>>>>> diff --git a/arch/arm64/tools/sysreg b/arch/arm64/tools/sysreg
>>>>> index b081b54d6d22..4ba167089e2a 100644
>>>>> --- a/arch/arm64/tools/sysreg
>>>>> +++ b/arch/arm64/tools/sysreg
>>>>> @@ -48,6 +48,8 @@
>>>>>    # feature that introduces them (eg, FEAT_LS64_ACCDATA introduces enumeration
>>>>>    # item ACCDATA) though it may be more taseful to do something else.
>>>>>    +# Please try to keep entries in this file sorted by sysreg
>>>>> encoding.
>>>>> +
>>>>>    Sysreg   OSDTRRX_EL1     2       0       0       0       2
>>>>>    Res0     63:32
>>>>>    Field    31:0    DTRRX
>>>>
>>>> "Do as I say, don't do as I do".
>>>>
>>>> I don't think this makes any sense if we don't actually sort the file
>>>> the first place.
>>>>
>>>>      M.
>>>>
>>>
>>> I think it's ok if it avoids review comments that new entries should
>>> be sorted. Or maybe we do the opposite and the comment should say this
>>> file is allowed to be unsorted...
>>
>> The better option would be to add the comment *and* sort the file.
>> Leading by example has some value, it seems.
> 
> IME, it's better if documentation just states what the tools enforce.
> 
> Can't we add something like this to the header generation:
> 
> $ grep '^Sysreg\s' arch/arm64/tools/sysreg | sort -n -k3 -k4 -k5 -k6 -k7 -c
> sort: -:22: disorder: Sysreg ID_MMFR4_EL1       3       0       0
>   2       6
> 
> Rob

Actually I updated gen-sysreg.awk to fail the build if it's not sorted, 
was just about to post it. I don't know if a build failure or a warning 
is preferred but I can do either.

James