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crypto: arm64/aes-blk - add 4 way interleave to CBC-MAC encrypt path 

CBC MAC is strictly sequential, and so the current AES code simply
processes the input one block at a time. However, we are about to add
yield support, which adds a bit of overhead, and which we prefer to
align with other modes in terms of granularity (i.e., it is better to
have all routines yield every 64 bytes and not have an exception for
CBC MAC which yields every 16 bytes)

So unroll the loop by 4. We still cannot perform the AES algorithm in
parallel, but we can at least merge the loads and stores.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Ard Biesheuvel 2018-03-10 15:21:53 +00:00 committed by Herbert Xu
parent a8f8a69e82
commit 870c163a0e
1 changed files with 21 additions and 2 deletions
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23
arch/arm64/crypto/aes-modes.S
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@ -395,8 +395,28 @@ AES_ENDPROC(aes_xts_decrypt)
AES_ENTRY(aes_mac_update) AES_ENTRY(aes_mac_update)
ld1 {v0.16b}, [x4] /* get dg */ ld1 {v0.16b}, [x4] /* get dg */
enc_prepare w2, x1, x7 enc_prepare w2, x1, x7
cbnz w5, .Lmacenc cbz w5, .Lmacloop4x
encrypt_block v0, w2, x1, x7, w8
.Lmacloop4x:
subs w3, w3, #4
bmi .Lmac1x
ld1 {v1.16b-v4.16b}, [x0], #64 /* get next pt block */
eor v0.16b, v0.16b, v1.16b /* ..and xor with dg */
encrypt_block v0, w2, x1, x7, w8
eor v0.16b, v0.16b, v2.16b
encrypt_block v0, w2, x1, x7, w8
eor v0.16b, v0.16b, v3.16b
encrypt_block v0, w2, x1, x7, w8
eor v0.16b, v0.16b, v4.16b
cmp w3, wzr
csinv x5, x6, xzr, eq
cbz w5, .Lmacout
encrypt_block v0, w2, x1, x7, w8
b .Lmacloop4x
.Lmac1x:
add w3, w3, #4
.Lmacloop: .Lmacloop:
cbz w3, .Lmacout cbz w3, .Lmacout
ld1 {v1.16b}, [x0], #16 /* get next pt block */ ld1 {v1.16b}, [x0], #16 /* get next pt block */
@ -406,7 +426,6 @@ AES_ENTRY(aes_mac_update)
csinv x5, x6, xzr, eq csinv x5, x6, xzr, eq
cbz w5, .Lmacout cbz w5, .Lmacout
.Lmacenc:
encrypt_block v0, w2, x1, x7, w8 encrypt_block v0, w2, x1, x7, w8
b .Lmacloop b .Lmacloop