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Commit a8f8a69e authored by Ard Biesheuvel's avatar Ard Biesheuvel Committed by Herbert Xu
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crypto: arm64/aes-blk - add 4 way interleave to CBC encrypt path 



CBC encryption 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 encrypt 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: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent 55868b45

arch/arm64/crypto/aes-modes.S

+25 −6
Original line number Diff line number Diff line
@@ -94,17 +94,36 @@ AES_ENDPROC(aes_ecb_decrypt) 
	 */



AES_ENTRY(aes_cbc_encrypt)

	ld1		{v0.16b}, [x5]			/* get iv */

	ld1		{v4.16b}, [x5]			/* get iv */

	enc_prepare	w3, x2, x6



.Lcbcencloop:

	ld1		{v1.16b}, [x1], #16		/* get next pt block */

	eor		v0.16b, v0.16b, v1.16b		/* ..and xor with iv */

.Lcbcencloop4x:

	subs		w4, w4, #4

	bmi		.Lcbcenc1x

	ld1		{v0.16b-v3.16b}, [x1], #64	/* get 4 pt blocks */

	eor		v0.16b, v0.16b, v4.16b		/* ..and xor with iv */

	encrypt_block	v0, w3, x2, x6, w7

	st1		{v0.16b}, [x0], #16

	eor		v1.16b, v1.16b, v0.16b

	encrypt_block	v1, w3, x2, x6, w7

	eor		v2.16b, v2.16b, v1.16b

	encrypt_block	v2, w3, x2, x6, w7

	eor		v3.16b, v3.16b, v2.16b

	encrypt_block	v3, w3, x2, x6, w7

	st1		{v0.16b-v3.16b}, [x0], #64

	mov		v4.16b, v3.16b

	b		.Lcbcencloop4x

.Lcbcenc1x:

	adds		w4, w4, #4

	beq		.Lcbcencout

.Lcbcencloop:

	ld1		{v0.16b}, [x1], #16		/* get next pt block */

	eor		v4.16b, v4.16b, v0.16b		/* ..and xor with iv */

	encrypt_block	v4, w3, x2, x6, w7

	st1		{v4.16b}, [x0], #16

	subs		w4, w4, #1

	bne		.Lcbcencloop

	st1		{v0.16b}, [x5]			/* return iv */

.Lcbcencout:

	st1		{v4.16b}, [x5]			/* return iv */

	ret

AES_ENDPROC(aes_cbc_encrypt)