Since commit aefbab8e77eb ("arm64: fpsimd: Preserve/restore kernel mode
NEON at context switch"), kernel-mode NEON sections have been
preemptible on arm64.  And since commit 7dadeaa6e851 ("sched: Further
restrict the preemption modes"), voluntary preemption is no longer
supported on arm64 either.  Therefore, there's no longer any need to
limit the length of kernel-mode NEON sections on arm64.

Simplify the AES-CBC-MAC code accordingly.

Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20260401000548.133151-2-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>

CONFIG_KERNEL_MODE_NEON is always enabled on arm64, and it always has
been since its introduction in 2013.  Given that and the fact that the
usefulness of kernel-mode NEON has only been increasing over time,
checking for this option in arm64-specific code is unnecessary.  Remove
these checks from lib/crypto/ to simplify the code and prevent any
future bugs where e.g. code gets disabled due to a typo in this logic.

Acked-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20260314175049.26931-1-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>

Instead of exposing the arm64-optimized CMAC, XCBC-MAC, and CBC-MAC code
via arm64-specific crypto_shash algorithms, instead just implement the
aes_cbcmac_blocks_arch() library function.  This is much simpler, it
makes the corresponding library functions be arm64-optimized, and it
fixes the longstanding issue where this optimized code was disabled by
default.  The corresponding algorithms still remain available through
crypto_shash, but individual architectures no longer need to handle it.

Note that to be compatible with the library using 'size_t' lengths, the
type of the return value and 'blocks' parameter to the assembly
functions had to be changed to 'size_t', and the assembly code had to be
updated accordingly to use the corresponding 64-bit registers.

Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20260218213501.136844-6-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>

To migrate the support for CBC-based MACs into libaes, the corresponding
arm64 assembly code needs to be moved there.  However, the arm64 AES
assembly code groups many AES modes together; individual modes aren't
easily separable.  (This isn't unique to arm64; other architectures
organize their AES modes similarly.)

Since the other AES modes will be migrated into the library eventually
too, just move the full assembly files for the AES modes into the
library.  (This is similar to what I already did for PowerPC and SPARC.)

Specifically: move the assembly files aes-ce.S, aes-modes.S, and
aes-neon.S and their build rules; declare the assembly functions in
<crypto/aes.h>; and export the assembly functions from libaes.

Note that the exports and public declarations of the assembly functions
are temporary.  They exist only to keep arch/arm64/crypto/ working until
the AES modes are fully moved into the library.

Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20260218213501.136844-5-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>

Move the ARM64 optimized AES key expansion and single-block AES
en/decryption code into lib/crypto/, wire it up to the AES library API,
and remove the superseded crypto_cipher algorithms.

The result is that both the AES library and crypto_cipher APIs are now
optimized for ARM64, whereas previously only crypto_cipher was (and the
optimizations weren't enabled by default, which this fixes as well).

Note: to see the diff from arch/arm64/crypto/aes-ce-glue.c to
lib/crypto/arm64/aes.h, view this commit with 'git show -M10'.

Acked-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20260112192035.10427-12-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>