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crypto: x86/sha256-ni - optimize code size

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- Load the SHA-256 round constants relative to a pointer that points
  into the middle of the constants rather than to the beginning.  Since
  x86 instructions use signed offsets, this decreases the instruction
  length required to access some of the later round constants.

- Use punpcklqdq or punpckhqdq instead of longer instructions such as
  pshufd, pblendw, and palignr.  This doesn't harm performance.

The end result is that sha256_ni_transform shrinks from 839 bytes to 791
bytes, with no loss in performance.

Suggested-by: Stefan Kanthak <stefan.kanthak@nexgo.de>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Eric Biggers 2024-04-11 09:23:58 -07:00 committed by Herbert Xu
parent 1b5ddb067d
commit 59e62b20ac
1 changed files with 15 additions and 15 deletions
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30
arch/x86/crypto/sha256_ni_asm.S
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@ -84,7 +84,7 @@
.else
movdqa \m0, MSG
.endif
paddd \i*4(SHA256CONSTANTS), MSG
paddd (\i-32)*4(SHA256CONSTANTS), MSG
sha256rnds2 STATE0, STATE1
.if \i >= 12 && \i < 60
movdqa \m0, TMP
@ -92,7 +92,7 @@
paddd TMP, \m1
sha256msg2 \m0, \m1
.endif
pshufd $0x0E, MSG, MSG
punpckhqdq MSG, MSG
sha256rnds2 STATE1, STATE0
.if \i >= 4 && \i < 52
sha256msg1 \m0, \m3
@ -128,17 +128,17 @@ SYM_TYPED_FUNC_START(sha256_ni_transform)
* Need to reorder these appropriately
* DCBA, HGFE -> ABEF, CDGH
*/
movdqu 0*16(DIGEST_PTR), STATE0
movdqu 1*16(DIGEST_PTR), STATE1
movdqu 0*16(DIGEST_PTR), STATE0 /* DCBA */
movdqu 1*16(DIGEST_PTR), STATE1 /* HGFE */
pshufd $0xB1, STATE0, STATE0 /* CDAB */
pshufd $0x1B, STATE1, STATE1 /* EFGH */
movdqa STATE0, TMP
palignr $8, STATE1, STATE0 /* ABEF */
pblendw $0xF0, TMP, STATE1 /* CDGH */
punpcklqdq STATE1, STATE0 /* FEBA */
punpckhqdq TMP, STATE1 /* DCHG */
pshufd $0x1B, STATE0, STATE0 /* ABEF */
pshufd $0xB1, STATE1, STATE1 /* CDGH */
movdqa PSHUFFLE_BYTE_FLIP_MASK(%rip), SHUF_MASK
lea K256(%rip), SHA256CONSTANTS
lea K256+32*4(%rip), SHA256CONSTANTS
.Lloop0:
/* Save hash values for addition after rounds */
@ -162,14 +162,14 @@ SYM_TYPED_FUNC_START(sha256_ni_transform)
jne .Lloop0
/* Write hash values back in the correct order */
pshufd $0x1B, STATE0, STATE0 /* FEBA */
pshufd $0xB1, STATE1, STATE1 /* DCHG */
movdqa STATE0, TMP
pblendw $0xF0, STATE1, STATE0 /* DCBA */
palignr $8, TMP, STATE1 /* HGFE */
punpcklqdq STATE1, STATE0 /* GHEF */
punpckhqdq TMP, STATE1 /* ABCD */
pshufd $0xB1, STATE0, STATE0 /* HGFE */
pshufd $0x1B, STATE1, STATE1 /* DCBA */
movdqu STATE0, 0*16(DIGEST_PTR)
movdqu STATE1, 1*16(DIGEST_PTR)
movdqu STATE1, 0*16(DIGEST_PTR)
movdqu STATE0, 1*16(DIGEST_PTR)
.Ldone_hash: