On 8/27/24 04:53, Oliver Upton wrote:
> Hi D Scott,
>
> On Mon, Aug 26, 2024 at 02:59:33PM -0700, D Scott Phillips wrote:
>> The ampere1a cpu is affected by erratum AC04_CPU_10 which is the same
>> bug as AC03_CPU38. Add ampere1a to the AC03_CPU_38 workaround midr list.
>>
>> Signed-off-by: D Scott Phillips <scott@xxxxxxxxxxxxxxxxxxxxxx>
>> ---
>> Documentation/arch/arm64/silicon-errata.rst | 2 ++
>> arch/arm64/Kconfig | 2 +-
>> arch/arm64/include/asm/cputype.h | 2 ++
>> arch/arm64/kernel/cpu_errata.c | 1 +
>> 4 files changed, 6 insertions(+), 1 deletion(-)
>>
>> diff --git a/Documentation/arch/arm64/silicon-errata.rst b/Documentation/arch/arm64/silicon-errata.rst
>> index 50327c05be8d1..39c52385f11fb 100644
>> --- a/Documentation/arch/arm64/silicon-errata.rst
>> +++ b/Documentation/arch/arm64/silicon-errata.rst
>> @@ -55,6 +55,8 @@ stable kernels.
>> +----------------+-----------------+-----------------+-----------------------------+
>> | Ampere | AmpereOne | AC03_CPU_38 | AMPERE_ERRATUM_AC03_CPU_38 |
>> +----------------+-----------------+-----------------+-----------------------------+
>> +| Ampere | AmpereOne AC04 | AC04_CPU_10 | AMPERE_ERRATUM_AC03_CPU_38 |
>> ++----------------+-----------------+-----------------+-----------------------------+
>
> We tend to stick the marketing term for a part in the second column so
> it is more recognizable for the user. Is this a placeholder for something
> different from "ampere1a"?
Agreed, even the MIDR being added here is for AMPERE1A. Probably something
like 'AmpereOneA' might be more suitable.
>
>> diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c
>> index f6b6b45073571..748aa536446ae 100644
>> --- a/arch/arm64/kernel/cpu_errata.c
>> +++ b/arch/arm64/kernel/cpu_errata.c
>> @@ -773,6 +773,7 @@ const struct arm64_cpu_capabilities arm64_errata[] = {
>> .desc = "AmpereOne erratum AC03_CPU_38",
>> .capability = ARM64_WORKAROUND_AMPERE_AC03_CPU_38,
>> ERRATA_MIDR_ALL_VERSIONS(MIDR_AMPERE1),
>> + ERRATA_MIDR_ALL_VERSIONS(MIDR_AMPERE1A),
>
> This will break the workaround on AC03, since the second macro reassigns
> ::midr_range.
>
> You'll want to use ERRATA_MIDR_RANGE_LIST() instead w/ an array of
> affected MIDRs.
>
+1
Although ERRATA_MIDR_RANGE_LIST() in turn creates such a list.
