James Morse f794954635 BACKPORT: 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>

Conflicts:
	arch/arm64/include/asm/sysreq.h

1. Added definition for ID_AA64ISAR1_EL1_BF16_MASK

Bug: 261510586
Change-Id: I83a5dd577fc8c0edd83c40b21f3fe54c54b6a9fa
(cherry picked from commit 1bdb0fbb2e27c51a6f311867726462c983a1d9ee)
Signed-off-by: Suren Baghdasaryan <surenb@google.com>

2023-01-09 21:43:48 +00:00

18 KiB

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