arm64: errata: Remove AES hwcap for COMPAT tasks
authorJames Morse <james.morse@arm.com>
Thu, 14 Jul 2022 16:15:23 +0000 (17:15 +0100)
committerWill Deacon <will@kernel.org>
Tue, 19 Jul 2022 18:27:01 +0000 (19:27 +0100)
commit44b3834b2eed595af07021b1c64e6f9bc396398b
tree6edd3d5aeff720c50d407985db85f122ca3bd394
parent39fdb65f52e9a53d32a6ba719f96669fd300ae78
arm64: errata: Remove AES hwcap for COMPAT tasks

Cortex-A57 and Cortex-A72 have an erratum where an interrupt that
occurs between a pair of AES instructions in aarch32 mode may corrupt
the ELR. The task will subsequently produce the wrong AES result.

The AES instructions are part of the cryptographic extensions, which are
optional. User-space software will detect the support for these
instructions from the hwcaps. If the platform doesn't support these
instructions a software implementation should be used.

Remove the hwcap bits on affected parts to indicate user-space should
not use the AES instructions.

Acked-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: James Morse <james.morse@arm.com>
Link: https://lore.kernel.org/r/20220714161523.279570-3-james.morse@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
Documentation/arm64/silicon-errata.rst
arch/arm64/Kconfig
arch/arm64/kernel/cpu_errata.c
arch/arm64/kernel/cpufeature.c
arch/arm64/tools/cpucaps