Re: [PATCH v2] arm64: Subscribe Microsoft Azure Cobalt 100 to ARM Neoverse N2 errata

[Anshuman Khandual]

On 2/14/24 23:25, Easwar Hariharan wrote:
> Add the MIDR value of Microsoft Azure Cobalt 100, which is a Microsoft
> implemented CPU based on r0p0 of the ARM Neoverse N2 CPU, and therefore
> suffers from all the same errata.
> 
> CC: stable@xxxxxxxxxxxxxxx # 5.15+
> Signed-off-by: Easwar Hariharan <eahariha@xxxxxxxxxxxxxxxxxxx>

Reviewed-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>

> ---
> changelog:
> v1->v2:
> * v1: https://lore.kernel.org/linux-arm-kernel/20240212232909.2276378-1-eahariha@xxxxxxxxxxxxxxxxxxx/T/#u
> * Consistently use MICROSOFT throughout
> ---
>  Documentation/arch/arm64/silicon-errata.rst | 7 +++++++
>  arch/arm64/include/asm/cputype.h            | 4 ++++
>  arch/arm64/kernel/cpu_errata.c              | 3 +++
>  3 files changed, 14 insertions(+)
> 
> diff --git a/Documentation/arch/arm64/silicon-errata.rst b/Documentation/arch/arm64/silicon-errata.rst
> index e8c2ce1f9df6..45a7f4932fe0 100644
> --- a/Documentation/arch/arm64/silicon-errata.rst
> +++ b/Documentation/arch/arm64/silicon-errata.rst
> @@ -243,3 +243,10 @@ stable kernels.
>  +----------------+-----------------+-----------------+-----------------------------+
>  | ASR            | ASR8601         | #8601001        | N/A                         |
>  +----------------+-----------------+-----------------+-----------------------------+
> ++----------------+-----------------+-----------------+-----------------------------+
> +| Microsoft      | Azure Cobalt 100| #2139208        | ARM64_ERRATUM_2139208       |
> ++----------------+-----------------+-----------------+-----------------------------+
> +| Microsoft      | Azure Cobalt 100| #2067961        | ARM64_ERRATUM_2067961       |
> ++----------------+-----------------+-----------------+-----------------------------+
> +| Microsoft      | Azure Cobalt 100| #2253138        | ARM64_ERRATUM_2253138       |
> ++----------------+-----------------+-----------------+-----------------------------+
> diff --git a/arch/arm64/include/asm/cputype.h b/arch/arm64/include/asm/cputype.h
> index 7c7493cb571f..52f076afeb96 100644
> --- a/arch/arm64/include/asm/cputype.h
> +++ b/arch/arm64/include/asm/cputype.h
> @@ -61,6 +61,7 @@
>  #define ARM_CPU_IMP_HISI		0x48
>  #define ARM_CPU_IMP_APPLE		0x61
>  #define ARM_CPU_IMP_AMPERE		0xC0
> +#define ARM_CPU_IMP_MICROSOFT		0x6D
>  
>  #define ARM_CPU_PART_AEM_V8		0xD0F
>  #define ARM_CPU_PART_FOUNDATION		0xD00
> @@ -135,6 +136,8 @@
>  
>  #define AMPERE_CPU_PART_AMPERE1		0xAC3
>  
> +#define MICROSOFT_CPU_PART_AZURE_COBALT_100	0xD49 /* Based on r0p0 of ARM Neoverse N2 */
> +
>  #define MIDR_CORTEX_A53 MIDR_CPU_MODEL(ARM_CPU_IMP_ARM, ARM_CPU_PART_CORTEX_A53)
>  #define MIDR_CORTEX_A57 MIDR_CPU_MODEL(ARM_CPU_IMP_ARM, ARM_CPU_PART_CORTEX_A57)
>  #define MIDR_CORTEX_A72 MIDR_CPU_MODEL(ARM_CPU_IMP_ARM, ARM_CPU_PART_CORTEX_A72)
> @@ -193,6 +196,7 @@
>  #define MIDR_APPLE_M2_BLIZZARD_MAX MIDR_CPU_MODEL(ARM_CPU_IMP_APPLE, APPLE_CPU_PART_M2_BLIZZARD_MAX)
>  #define MIDR_APPLE_M2_AVALANCHE_MAX MIDR_CPU_MODEL(ARM_CPU_IMP_APPLE, APPLE_CPU_PART_M2_AVALANCHE_MAX)
>  #define MIDR_AMPERE1 MIDR_CPU_MODEL(ARM_CPU_IMP_AMPERE, AMPERE_CPU_PART_AMPERE1)
> +#define MIDR_MICROSOFT_AZURE_COBALT_100 MIDR_CPU_MODEL(ARM_CPU_IMP_MICROSOFT, MICROSOFT_CPU_PART_AZURE_COBALT_100)
>  
>  /* Fujitsu Erratum 010001 affects A64FX 1.0 and 1.1, (v0r0 and v1r0) */
>  #define MIDR_FUJITSU_ERRATUM_010001		MIDR_FUJITSU_A64FX
> diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c
> index 967c7c7a4e7d..76b8dd37092a 100644
> --- a/arch/arm64/kernel/cpu_errata.c
> +++ b/arch/arm64/kernel/cpu_errata.c
> @@ -374,6 +374,7 @@ static const struct midr_range erratum_1463225[] = {
>  static const struct midr_range trbe_overwrite_fill_mode_cpus[] = {
>  #ifdef CONFIG_ARM64_ERRATUM_2139208
>  	MIDR_ALL_VERSIONS(MIDR_NEOVERSE_N2),
> +	MIDR_ALL_VERSIONS(MIDR_MICROSOFT_AZURE_COBALT_100),
>  #endif
>  #ifdef CONFIG_ARM64_ERRATUM_2119858
>  	MIDR_ALL_VERSIONS(MIDR_CORTEX_A710),
> @@ -387,6 +388,7 @@ static const struct midr_range trbe_overwrite_fill_mode_cpus[] = {
>  static const struct midr_range tsb_flush_fail_cpus[] = {
>  #ifdef CONFIG_ARM64_ERRATUM_2067961
>  	MIDR_ALL_VERSIONS(MIDR_NEOVERSE_N2),
> +	MIDR_ALL_VERSIONS(MIDR_MICROSOFT_AZURE_COBALT_100),
>  #endif
>  #ifdef CONFIG_ARM64_ERRATUM_2054223
>  	MIDR_ALL_VERSIONS(MIDR_CORTEX_A710),
> @@ -399,6 +401,7 @@ static const struct midr_range tsb_flush_fail_cpus[] = {
>  static struct midr_range trbe_write_out_of_range_cpus[] = {
>  #ifdef CONFIG_ARM64_ERRATUM_2253138
>  	MIDR_ALL_VERSIONS(MIDR_NEOVERSE_N2),
> +	MIDR_ALL_VERSIONS(MIDR_MICROSOFT_AZURE_COBALT_100),
>  #endif
>  #ifdef CONFIG_ARM64_ERRATUM_2224489
>  	MIDR_ALL_VERSIONS(MIDR_CORTEX_A710),