Re: [PATCH v3 02/22] arm64: Generate sign macro for sysreg Enums

Colton Lewis
2025-06-27T20:45:40Z

Hi Ben. Thanks for the review.

Ben Horgan <ben.horgan@arm.com> writes:

> Hi Colton,

> On 6/26/25 21:04, Colton Lewis wrote:
>> There's no reason Enums shouldn't be equivalent to UnsignedEnums and
>> explicitly specify they are unsigned. This will avoid the annoyance I
>> had with HPMN0.
> An Enum can be annotated with the field's sign by updating it to
> UnsignedEnum or SignedEnum. This is explained in [1].

> With this change ID_AA64PFR1_EL1.MTE_frac would be marked as unsigned
> when it should really be considered signed.

> Enum 43:40 MTE_frac
> 0b0000 ASYNC
> 0b1111 NI
> EndEnum

Thanks for the explanation. I made this a separate commit because I
considered people might object and HPMN0 is already an UnsignedEnum in
my previous commit.

Do you think it would be a good idea to make plain Enums signed by
default or should I just remove this commit from the series?

>> Signed-off-by: Colton Lewis <coltonlewis@google.com>
>> ---
>> arch/arm64/tools/gen-sysreg.awk | 1 +
>> 1 file changed, 1 insertion(+)

>> diff --git a/arch/arm64/tools/gen-sysreg.awk
>> b/arch/arm64/tools/gen-sysreg.awk
>> index f2a1732cb1f6..fa21a632d9b7 100755
>> --- a/arch/arm64/tools/gen-sysreg.awk
>> +++ b/arch/arm64/tools/gen-sysreg.awk
>> @@ -308,6 +308,7 @@ $1 == "Enum" && (block_current() == "Sysreg" ||
>> block_current() == "SysregFields
>> parse_bitdef(reg, field, $2)

>> define_field(reg, field, msb, lsb)
>> + define_field_sign(reg, field, "false")

>> next
>> }

> Thanks,

> Ben

> [1]
> https://lore.kernel.org/all/20221207-arm64-sysreg-helpers-v4-1-25b6b3fb9d18@kernel.org/