Bug#922204: linux-image-4.19.0-3-armmp-lpae: Kernel mode NEON support should be enabled
Package: linux-image-4.19.0-3-armmp-lpae
Severity: important
Dear Maintainer,
Currently, the 32-bit ARM kernels are built without support for kernel mode
NEON, which means that none of the modules that depend on it are built either.
This mostly affects crypto drivers, as well as RAID6 and XOR. This is mostly a
performance problem, although the fact that the non-NEON AES is not time
invariant implies that systems may be susceptible to cache timing attacks
needlessly.
Note that there is also a runtime check, so even with
CONFIG_KERNEL_MODE_NEON=y, systems without a NEON implementation will still run
as before.
The XOR and RAID6 code will automatically be built with NEON support once the
CONFIG_KERNEL_MODE_NEON option is set. For the crypto part, the following ones
should be set to =m as well. (The CE ones rely on ARMv8 crypto instructions so
they are not as relevant, but they can easily be enabled at the same time)
config CRYPTO_SHA1_ARM_NEON
config CRYPTO_AES_ARM_BS
config CRYPTO_CHACHA20_NEON
config CRYPTO_SHA1_ARM_CE
config CRYPTO_SHA2_ARM_CE
config CRYPTO_AES_ARM_CE
config CRYPTO_GHASH_ARM_CE
config CRYPTO_CRCT10DIF_ARM_CE
config CRYPTO_CRC32_ARM_CE
Note that this applies equally to the non-LPAE configuration.
-- System Information:
Debian Release: 9.7
APT prefers stable
APT policy: (990, 'stable'), (500, 'stable-updates'), (500, 'unstable'), (500, 'testing'), (1, 'experimental')
Architecture: arm64 (aarch64)
Kernel: Linux 5.0.0-rc6+ (SMP w/24 CPU cores; PREEMPT)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), LANGUAGE=en_US:en (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)
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