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| author | James Morse <james.morse@arm.com> | 2022-09-09 17:59:38 +0100 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2022-09-16 15:23:50 +0100 |
| commit | 1bdb0fbb2e27c51a6f311867726462c983a1d9ee (patch) | |
| tree | 729c45d634d041e7e6e9a306d91c6692011664a9 /arch/arm64/Kconfig | |
| parent | 445c953e4a84b2942bdb5c0b5aff571c903680fe (diff) | |
| download | linux-1bdb0fbb2e27c51a6f311867726462c983a1d9ee.tar.gz linux-1bdb0fbb2e27c51a6f311867726462c983a1d9ee.tar.bz2 linux-1bdb0fbb2e27c51a6f311867726462c983a1d9ee.zip | |
arm64: errata: remove BF16 HWCAP due to incorrect result on Cortex-A510
Cortex-A510's erratum #2658417 causes two BF16 instructions to return the
wrong result in rare circumstances when a pair of A510 CPUs are using
shared neon hardware.
The two instructions affected are BFMMLA and VMMLA, support for these is
indicated by the BF16 HWCAP. Remove it on affected platforms.
Signed-off-by: James Morse <james.morse@arm.com>
Link: https://lore.kernel.org/r/20220909165938.3931307-4-james.morse@arm.com
[catalin.marinas@arm.com: add revision to the Kconfig help; remove .type]
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64/Kconfig')
| -rw-r--r-- | arch/arm64/Kconfig | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 9fb9fff08c94..526ab76cd233 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -733,6 +733,19 @@ config ARM64_ERRATUM_2077057 If unsure, say Y. +config ARM64_ERRATUM_2658417 + bool "Cortex-A510: 2658417: remove BF16 support due to incorrect result" + default y + help + This option adds the workaround for ARM Cortex-A510 erratum 2658417. + Affected Cortex-A510 (r0p0 to r1p1) may produce the wrong result for + BFMMLA or VMMLA instructions in rare circumstances when a pair of + A510 CPUs are using shared neon hardware. As the sharing is not + discoverable by the kernel, hide the BF16 HWCAP to indicate that + user-space should not be using these instructions. + + If unsure, say Y. + config ARM64_ERRATUM_2119858 bool "Cortex-A710/X2: 2119858: workaround TRBE overwriting trace data in FILL mode" default y |