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)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Sat, 29 Oct 2022 08:12:53 +0000 (10:12 +0200)
commit8ddc58e0e312f85e975f350cbe43ba1d9836eb1f
tree1995392638765867d0e59a2379b19136952bf3d5
parent738515cf8bb48c6a1a8a59db140bd226a4c5a70a
arm64: errata: Remove AES hwcap for COMPAT tasks

commit 44b3834b2eed595af07021b1c64e6f9bc396398b upstream.

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>
[florian: resolved conflicts in arch/arm64/tools/cpucaps and cpu_errata.c]
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Documentation/arm64/silicon-errata.rst
arch/arm64/Kconfig
arch/arm64/kernel/cpu_errata.c
arch/arm64/kernel/cpufeature.c
arch/arm64/tools/cpucaps