crypto: x86/aes-xts - handle AES-128 and AES-192 more efficiently

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Decrease the amount of code specific to the different AES variants by
"right-aligning" the sequence of round keys, and for AES-128 and AES-192
just skipping irrelevant rounds at the beginning.

This shrinks the size of aes-xts-avx-x86_64.o by 13.3%, and it improves
the efficiency of AES-128 and AES-192.  The tradeoff is that for AES-256
some additional not-taken conditional jumps are now executed.  But these
are predicted well and are cheap on x86.

Note that the ARMv8 CE based AES-XTS implementation uses a similar
strategy to handle the different AES variants.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

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Eric Biggers 2024-04-12 20:17:26 -07:00 • committed by Herbert Xu

parent ea9459ef36

commit 2717e01fc3

1 changed files with 92 additions and 86 deletions

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arch/x86/crypto/aes-xts-avx-x86_64.S

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