Re: [PATCH v2 17/17] arm64: Advertise TRBE erratum workaround for write to out-of-range address

[Anshuman Khandual]

On 9/21/21 7:11 PM, Suzuki K Poulose wrote:
> Add Kconfig entries for the errata workarounds for TRBE writing
> to an out-of-range address.
> 
> Cc: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
> Cc: Anshuman Khandual <anshuman.khandual@xxxxxxx>
> Cc: Mike Leach <mike.leach@xxxxxxxxxx>
> Cc: Leo Yan <leo.yan@xxxxxxxxxx>
> Signed-off-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>

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

> ---
>  Documentation/arm64/silicon-errata.rst |  4 +++
>  arch/arm64/Kconfig                     | 39 ++++++++++++++++++++++++++
>  2 files changed, 43 insertions(+)
> 
> diff --git a/Documentation/arm64/silicon-errata.rst b/Documentation/arm64/silicon-errata.rst
> index 569a92411dcd..5342e895fb60 100644
> --- a/Documentation/arm64/silicon-errata.rst
> +++ b/Documentation/arm64/silicon-errata.rst
> @@ -96,6 +96,8 @@ stable kernels.
>  +----------------+-----------------+-----------------+-----------------------------+
>  | ARM            | Cortex-A710     | #2054223        | ARM64_ERRATUM_2054223       |
>  +----------------+-----------------+-----------------+-----------------------------+
> +| ARM            | Cortex-A710     | #2224489        | ARM64_ERRATUM_2224489       |
> ++----------------+-----------------+-----------------+-----------------------------+
>  | ARM            | Neoverse-N1     | #1188873,1418040| ARM64_ERRATUM_1418040       |
>  +----------------+-----------------+-----------------+-----------------------------+
>  | ARM            | Neoverse-N1     | #1349291        | N/A                         |
> @@ -106,6 +108,8 @@ stable kernels.
>  +----------------+-----------------+-----------------+-----------------------------+
>  | ARM            | Neoverse-N2     | #2067961        | ARM64_ERRATUM_2067961       |
>  +----------------+-----------------+-----------------+-----------------------------+
> +| ARM            | Neoverse-N2     | #2253138        | ARM64_ERRATUM_2253138       |
> ++----------------+-----------------+-----------------+-----------------------------+
>  | ARM            | MMU-500         | #841119,826419  | N/A                         |
>  +----------------+-----------------+-----------------+-----------------------------+
>  +----------------+-----------------+-----------------+-----------------------------+
> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> index 0764774e12bb..611ae02aabbd 100644
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -736,6 +736,45 @@ config ARM64_ERRATUM_2067961
>  
>  	  If unsure, say Y.
>  
> +config ARM64_WORKAROUND_TRBE_WRITE_OUT_OF_RANGE
> +	bool
> +
> +config ARM64_ERRATUM_2253138
> +	bool "Neoverse-N2: 2253138: workaround TRBE writing to address out-of-range"
> +	depends on CORESIGHT_TRBE
> +	default y
> +	select ARM64_WORKAROUND_TRBE_WRITE_OUT_OF_RANGE
> +	help
> +	  This option adds the workaround for ARM Neoverse-N2 erratum 2253138.
> +
> +	  Affected Neoverse-N2 cores might write to an out-of-range address, not reserved
> +	  for TRBE. Under some conditions, the TRBE might generate a write to the next
> +	  virtually addressed page following the last page of the TRBE address space
> +	  (i.e, the TRBLIMITR_EL1.LIMIT), instead of wrapping around to the base.
> +
> +	  We work around this in the driver by, always making sure that there is a
> +	  page beyond the TRBLIMITR_EL1.LIMIT, within the space allowed for the TRBE.
> +
> +	  If unsure, say Y.
> +
> +config ARM64_ERRATUM_2224489
> +	bool "Cortex-A710: 2224489: workaround TRBE writing to address out-of-range"
> +	depends on CORESIGHT_TRBE
> +	default y
> +	select ARM64_WORKAROUND_TRBE_WRITE_OUT_OF_RANGE
> +	help
> +	  This option adds the workaround for ARM Cortex-A710 erratum 2224489.
> +
> +	  Affected Cortex-A710 cores might write to an out-of-range address, not reserved
> +	  for TRBE. Under some conditions, the TRBE might generate a write to the next
> +	  virtually addressed page following the last page of the TRBE address space
> +	  (i.e, the TRBLIMITR_EL1.LIMIT), instead of wrapping around to the base.
> +
> +	  We work around this in the driver by, always making sure that there is a
> +	  page beyond the TRBLIMITR_EL1.LIMIT, within the space allowed for the TRBE.
> +
> +	  If unsure, say Y.
> +
>  config CAVIUM_ERRATUM_22375
>  	bool "Cavium erratum 22375, 24313"
>  	default y
>