Anshuman Khandual [off-list ref] writes:

On 8/27/24 04:53, Oliver Upton wrote:

quoted

Hi D Scott,

On Mon, Aug 26, 2024 at 02:59:33PM -0700, D Scott Phillips wrote:

quoted

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 <redacted>
---
 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.

"AmpereOne AC04" was given to me by our marketing department, so that
should be the user visible name of the part when they buy/use
it. ampere1a is the name of the core in the SoC and the thing you can
use in gcc's --mtune=, similar to "neoverse-n1" within "Ampere Altra".

quoted

quoted

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.

Oops, my mistake. I'll fix this.