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Commit cc3cc489 authored by Ard Biesheuvel's avatar Ard Biesheuvel Committed by Herbert Xu
Browse files

crypto: arm64/aes-blk - ensure XTS mask is always loaded 



Commit 2e5d2f33 ("crypto: arm64/aes-blk - improve XTS mask handling")
optimized away some reloads of the XTS mask vector, but failed to take
into account that calls into the XTS en/decrypt routines will take a
slightly different code path if a single block of input is split across
different buffers. So let's ensure that the first load occurs
unconditionally, and move the reload to the end so it doesn't occur
needlessly.

Fixes: 2e5d2f33 ("crypto: arm64/aes-blk - improve XTS mask handling")
Signed-off-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent 22a8118d

arch/arm64/crypto/aes-modes.S

+4 −4
Original line number Diff line number Diff line
@@ -359,18 +359,17 @@ AES_ENTRY(aes_xts_encrypt) 
	mov		x29, sp



	ld1		{v4.16b}, [x6]

	xts_load_mask	v8

	cbz		w7, .Lxtsencnotfirst



	enc_prepare	w3, x5, x8

	encrypt_block	v4, w3, x5, x8, w7		/* first tweak */

	enc_switch_key	w3, x2, x8

	xts_load_mask	v8

	b		.LxtsencNx



.Lxtsencnotfirst:

	enc_prepare	w3, x2, x8

.LxtsencloopNx:

	xts_reload_mask	v8

	next_tweak	v4, v4, v8

.LxtsencNx:

	subs		w4, w4, #4
@@ -391,6 +390,7 @@ AES_ENTRY(aes_xts_encrypt) 
	st1		{v0.16b-v3.16b}, [x0], #64

	mov		v4.16b, v7.16b

	cbz		w4, .Lxtsencout

	xts_reload_mask	v8

	b		.LxtsencloopNx

.Lxtsenc1x:

	adds		w4, w4, #4
@@ -417,18 +417,17 @@ AES_ENTRY(aes_xts_decrypt) 
	mov		x29, sp



	ld1		{v4.16b}, [x6]

	xts_load_mask	v8

	cbz		w7, .Lxtsdecnotfirst



	enc_prepare	w3, x5, x8

	encrypt_block	v4, w3, x5, x8, w7		/* first tweak */

	dec_prepare	w3, x2, x8

	xts_load_mask	v8

	b		.LxtsdecNx



.Lxtsdecnotfirst:

	dec_prepare	w3, x2, x8

.LxtsdecloopNx:

	xts_reload_mask	v8

	next_tweak	v4, v4, v8

.LxtsdecNx:

	subs		w4, w4, #4
@@ -449,6 +448,7 @@ AES_ENTRY(aes_xts_decrypt) 
	st1		{v0.16b-v3.16b}, [x0], #64

	mov		v4.16b, v7.16b

	cbz		w4, .Lxtsdecout

	xts_reload_mask	v8

	b		.LxtsdecloopNx

.Lxtsdec1x:

	adds		w4, w4, #4