diff options
| author | Oliver Upton <oliver.upton@linux.dev> | 2023-06-09 22:01:02 +0000 |
|---|---|---|
| committer | Oliver Upton <oliver.upton@linux.dev> | 2023-06-16 00:31:44 +0000 |
| commit | 6df696cd9bc1ceed0e92e36908f88bbd16d18255 (patch) | |
| tree | 7d169d9cc9b8f725c0d065e46b018ead5b8fd5fb /arch/arm64/tools/cpucaps | |
| parent | 44c026a73be8038f03dbdeef028b642880cf1511 (diff) | |
arm64: errata: Mitigate Ampere1 erratum AC03_CPU_38 at stage-2
AmpereOne has an erratum in its implementation of FEAT_HAFDBS that
required disabling the feature on the design. This was done by reporting
the feature as not implemented in the ID register, although the
corresponding control bits were not actually RES0. This does not align
well with the requirements of the architecture, which mandates these
bits be RES0 if HAFDBS isn't implemented.
The kernel's use of stage-1 is unaffected, as the HA and HD bits are
only set if HAFDBS is detected in the ID register. KVM, on the other
hand, relies on the RES0 behavior at stage-2 to use the same value for
VTCR_EL2 on any cpu in the system. Mitigate the non-RES0 behavior by
leaving VTCR_EL2.HA clear on affected systems.
Cc: stable@vger.kernel.org
Cc: D Scott Phillips <scott@os.amperecomputing.com>
Cc: Darren Hart <darren@os.amperecomputing.com>
Acked-by: D Scott Phillips <scott@os.amperecomputing.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20230609220104.1836988-2-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Diffstat (limited to 'arch/arm64/tools/cpucaps')
| -rw-r--r-- | arch/arm64/tools/cpucaps | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/arm64/tools/cpucaps b/arch/arm64/tools/cpucaps index 40ba95472594..9f9a2d6652eb 100644 --- a/arch/arm64/tools/cpucaps +++ b/arch/arm64/tools/cpucaps @@ -77,6 +77,7 @@ WORKAROUND_2077057 WORKAROUND_2457168 WORKAROUND_2645198 WORKAROUND_2658417 +WORKAROUND_AMPERE_AC03_CPU_38 WORKAROUND_TRBE_OVERWRITE_FILL_MODE WORKAROUND_TSB_FLUSH_FAILURE WORKAROUND_TRBE_WRITE_OUT_OF_RANGE |