[PATCH] arm64/sysreg: Update ID_AA64MMFR2_EL1 register

[PATCH] arm64/sysreg: Update ID_AA64MMFR2_EL1 register

[Anshuman Khandual]

This updates ID_AA64MMFR2_EL1.VARange register fields as per the definition
based on DDI0601 2024-03.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
---
This applies on v6.9-rc4

 arch/arm64/tools/sysreg | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm64/tools/sysreg b/arch/arm64/tools/sysreg
index a4c1dd4741a4..6d7213dcbeb5 100644
--- a/arch/arm64/tools/sysreg
+++ b/arch/arm64/tools/sysreg
@@ -1739,6 +1739,7 @@ EndEnum
 UnsignedEnum	19:16	VARange
 	0b0000	48
 	0b0001	52
+	0b0010	56
 EndEnum
 UnsignedEnum	15:12	IESB
 	0b0000	NI
-- 
2.25.1

Re: [PATCH] arm64/sysreg: Update ID_AA64MMFR2_EL1 register

[Will Deacon]

On Fri, Apr 19, 2024 at 07:43:25AM +0530, Anshuman Khandual wrote:
> This updates ID_AA64MMFR2_EL1.VARange register fields as per the definition
> based on DDI0601 2024-03.
> 
> Cc: Catalin Marinas <catalin.marinas@arm.com>
> Cc: Will Deacon <will@kernel.org>
> Cc: Mark Brown <broonie@kernel.org>
> Cc: linux-arm-kernel@lists.infradead.org
> Cc: linux-kernel@vger.kernel.org
> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
> ---
> This applies on v6.9-rc4
> 
>  arch/arm64/tools/sysreg | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/arch/arm64/tools/sysreg b/arch/arm64/tools/sysreg
> index a4c1dd4741a4..6d7213dcbeb5 100644
> --- a/arch/arm64/tools/sysreg
> +++ b/arch/arm64/tools/sysreg
> @@ -1739,6 +1739,7 @@ EndEnum
>  UnsignedEnum	19:16	VARange
>  	0b0000	48
>  	0b0001	52
> +	0b0010	56

Is anybody using this? I'm not sure there's a lot of value in adding
these fields one-by-one for the sake of completeness.

Will

Re: [PATCH] arm64/sysreg: Update ID_AA64MMFR2_EL1 register

[Anshuman Khandual]

On 4/19/24 19:16, Will Deacon wrote:
> On Fri, Apr 19, 2024 at 07:43:25AM +0530, Anshuman Khandual wrote:
>> This updates ID_AA64MMFR2_EL1.VARange register fields as per the definition
>> based on DDI0601 2024-03.
>>
>> Cc: Catalin Marinas <catalin.marinas@arm.com>
>> Cc: Will Deacon <will@kernel.org>
>> Cc: Mark Brown <broonie@kernel.org>
>> Cc: linux-arm-kernel@lists.infradead.org
>> Cc: linux-kernel@vger.kernel.org
>> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
>> ---
>> This applies on v6.9-rc4
>>
>>  arch/arm64/tools/sysreg | 1 +
>>  1 file changed, 1 insertion(+)
>>
>> diff --git a/arch/arm64/tools/sysreg b/arch/arm64/tools/sysreg
>> index a4c1dd4741a4..6d7213dcbeb5 100644
>> --- a/arch/arm64/tools/sysreg
>> +++ b/arch/arm64/tools/sysreg
>> @@ -1739,6 +1739,7 @@ EndEnum
>>  UnsignedEnum	19:16	VARange
>>  	0b0000	48
>>  	0b0001	52
>> +	0b0010	56
> 
> Is anybody using this? I'm not sure there's a lot of value in adding
> these fields one-by-one for the sake of completeness.

This is not being used currently but will be required for upcoming
features. I was under the impression that register fields (atleast
for the ID registers) should be kept updated, with latest released
spec ? Besides lately arch/arm64/tools/sysreg serves as very good
reference for all necessary register fields.

https://developer.arm.com/documentation/ddi0601/2024-03/AArch64-Registers/ID-AA64MMFR2-EL1--AArch64-Memory-Model-Feature-Register-2

Re: [PATCH] arm64/sysreg: Update ID_AA64MMFR2_EL1 register

[Will Deacon]

On Mon, Apr 22, 2024 at 08:38:40AM +0530, Anshuman Khandual wrote:
> 
> 
> On 4/19/24 19:16, Will Deacon wrote:
> > On Fri, Apr 19, 2024 at 07:43:25AM +0530, Anshuman Khandual wrote:
> >> This updates ID_AA64MMFR2_EL1.VARange register fields as per the definition
> >> based on DDI0601 2024-03.
> >>
> >> Cc: Catalin Marinas <catalin.marinas@arm.com>
> >> Cc: Will Deacon <will@kernel.org>
> >> Cc: Mark Brown <broonie@kernel.org>
> >> Cc: linux-arm-kernel@lists.infradead.org
> >> Cc: linux-kernel@vger.kernel.org
> >> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
> >> ---
> >> This applies on v6.9-rc4
> >>
> >>  arch/arm64/tools/sysreg | 1 +
> >>  1 file changed, 1 insertion(+)
> >>
> >> diff --git a/arch/arm64/tools/sysreg b/arch/arm64/tools/sysreg
> >> index a4c1dd4741a4..6d7213dcbeb5 100644
> >> --- a/arch/arm64/tools/sysreg
> >> +++ b/arch/arm64/tools/sysreg
> >> @@ -1739,6 +1739,7 @@ EndEnum
> >>  UnsignedEnum	19:16	VARange
> >>  	0b0000	48
> >>  	0b0001	52
> >> +	0b0010	56
> > 
> > Is anybody using this? I'm not sure there's a lot of value in adding
> > these fields one-by-one for the sake of completeness.
> 
> This is not being used currently but will be required for upcoming
> features. I was under the impression that register fields (atleast
> for the ID registers) should be kept updated, with latest released
> spec ? Besides lately arch/arm64/tools/sysreg serves as very good
> reference for all necessary register fields.

Why? The linux headers aren't documenting the architecture.

Will

Re: [PATCH] arm64/sysreg: Update ID_AA64MMFR2_EL1 register

[Mark Brown]

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On Mon, Apr 22, 2024 at 06:16:13PM +0100, Will Deacon wrote:
> On Mon, Apr 22, 2024 at 08:38:40AM +0530, Anshuman Khandual wrote:

> > This is not being used currently but will be required for upcoming
> > features. I was under the impression that register fields (atleast
> > for the ID registers) should be kept updated, with latest released
> > spec ? Besides lately arch/arm64/tools/sysreg serves as very good
> > reference for all necessary register fields.

> Why? The linux headers aren't documenting the architecture.

I don't know that it's something that we should be doing apropos of
nothing but if people have done updates and they're not unreasonbly
complicated to review it does seem useful to integrate them to avoid
duplicated work.  There have been some issues with that around the ID
registers (which are going to be on the places most prone to this I
guess).

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Re: [PATCH] arm64/sysreg: Update ID_AA64MMFR2_EL1 register

[Anshuman Khandual]

On 4/23/24 10:47, Mark Brown wrote:
> On Mon, Apr 22, 2024 at 06:16:13PM +0100, Will Deacon wrote:
>> On Mon, Apr 22, 2024 at 08:38:40AM +0530, Anshuman Khandual wrote:
> 
>>> This is not being used currently but will be required for upcoming
>>> features. I was under the impression that register fields (atleast
>>> for the ID registers) should be kept updated, with latest released
>>> spec ? Besides lately arch/arm64/tools/sysreg serves as very good
>>> reference for all necessary register fields.
> 
>> Why? The linux headers aren't documenting the architecture.
> 
> I don't know that it's something that we should be doing apropos of
> nothing but if people have done updates and they're not unreasonbly
> complicated to review it does seem useful to integrate them to avoid
> duplicated work.  There have been some issues with that around the ID
> registers (which are going to be on the places most prone to this I
> guess).

The other problem is by not updating the individual register fields with
the latest spec, it also gives an wrong impression about that field, and
also might create confusion.