From: Eric Biggers <ebiggers@xxxxxxxxxx>
Reorganize the main loop to free up the RNDKEYLAST[0-3] registers and
use them for more cached round keys. This improves performance by about
2% on AMD Zen 4 and Zen 5. Intel performance remains about the same.
Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx>
---
arch/x86/crypto/aes-gcm-avx10-x86_64.S | 99 ++++++++++----------------
1 file changed, 38 insertions(+), 61 deletions(-)
diff --git a/arch/x86/crypto/aes-gcm-avx10-x86_64.S b/arch/x86/crypto/aes-gcm-avx10-x86_64.S
index 8989bf9b8384..02ee11083d4f 100644
--- a/arch/x86/crypto/aes-gcm-avx10-x86_64.S
+++ b/arch/x86/crypto/aes-gcm-avx10-x86_64.S
@@ -86,11 +86,11 @@
.section .rodata
.p2align 6
// A shuffle mask that reflects the bytes of 16-byte blocks
.Lbswap_mask:
- .octa 0x000102030405060708090a0b0c0d0e0f
+ .octa 0x000102030405060708090a0b0c0d0e0f
// This is the GHASH reducing polynomial without its constant term, i.e.
// x^128 + x^7 + x^2 + x, represented using the backwards mapping
// between bits and polynomial coefficients.
//
@@ -560,10 +560,36 @@
vpxord RNDKEY0, V1, V1
vpxord RNDKEY0, V2, V2
vpxord RNDKEY0, V3, V3
.endm
+// Do the last AES round for four vectors of counter blocks V0-V3, XOR source
+// data with the resulting keystream, and write the result to DST and
+// GHASHDATA[0-3]. (Implementation differs slightly, but has the same effect.)
+.macro _aesenclast_and_xor_4x
+ // XOR the source data with the last round key, saving the result in
+ // GHASHDATA[0-3]. This reduces latency by taking advantage of the
+ // property vaesenclast(key, a) ^ b == vaesenclast(key ^ b, a).
+ vpxord 0*VL(SRC), RNDKEYLAST, GHASHDATA0
+ vpxord 1*VL(SRC), RNDKEYLAST, GHASHDATA1
+ vpxord 2*VL(SRC), RNDKEYLAST, GHASHDATA2
+ vpxord 3*VL(SRC), RNDKEYLAST, GHASHDATA3
+
+ // Do the last AES round. This handles the XOR with the source data
+ // too, as per the optimization described above.
+ vaesenclast GHASHDATA0, V0, GHASHDATA0
+ vaesenclast GHASHDATA1, V1, GHASHDATA1
+ vaesenclast GHASHDATA2, V2, GHASHDATA2
+ vaesenclast GHASHDATA3, V3, GHASHDATA3
+
+ // Store the en/decrypted data to DST.
+ vmovdqu8 GHASHDATA0, 0*VL(DST)
+ vmovdqu8 GHASHDATA1, 1*VL(DST)
+ vmovdqu8 GHASHDATA2, 2*VL(DST)
+ vmovdqu8 GHASHDATA3, 3*VL(DST)
+.endm
+
// void aes_gcm_{enc,dec}_update_##suffix(const struct aes_gcm_key_avx10 *key,
// const u32 le_ctr[4], u8 ghash_acc[16],
// const u8 *src, u8 *dst, int datalen);
//
// This macro generates a GCM encryption or decryption update function with the
@@ -638,29 +664,24 @@
.set LE_CTR_INC, V11
// LE_CTR contains the next set of little-endian counter blocks.
.set LE_CTR, V12
- // RNDKEY0, RNDKEYLAST, and RNDKEY_M[9-5] contain cached AES round keys,
+ // RNDKEY0, RNDKEYLAST, and RNDKEY_M[9-1] contain cached AES round keys,
// copied to all 128-bit lanes. RNDKEY0 is the zero-th round key,
// RNDKEYLAST the last, and RNDKEY_M\i the one \i-th from the last.
.set RNDKEY0, V13
.set RNDKEYLAST, V14
.set RNDKEY_M9, V15
.set RNDKEY_M8, V16
.set RNDKEY_M7, V17
.set RNDKEY_M6, V18
.set RNDKEY_M5, V19
-
- // RNDKEYLAST[0-3] temporarily store the last AES round key XOR'd with
- // the corresponding block of source data. This is useful because
- // vaesenclast(key, a) ^ b == vaesenclast(key ^ b, a), and key ^ b can
- // be computed in parallel with the AES rounds.
- .set RNDKEYLAST0, V20
- .set RNDKEYLAST1, V21
- .set RNDKEYLAST2, V22
- .set RNDKEYLAST3, V23
+ .set RNDKEY_M4, V20
+ .set RNDKEY_M3, V21
+ .set RNDKEY_M2, V22
+ .set RNDKEY_M1, V23
// GHASHTMP[0-2] are temporary variables used by _ghash_step_4x. These
// cannot coincide with anything used for AES encryption, since for
// performance reasons GHASH and AES encryption are interleaved.
.set GHASHTMP0, V24
@@ -746,30 +767,19 @@
vbroadcasti32x4 (%rax), RNDKEY
_vaesenc_4x RNDKEY
add $16, %rax
cmp %rax, RNDKEYLAST_PTR
jne 1b
- vpxord 0*VL(SRC), RNDKEYLAST, RNDKEYLAST0
- vpxord 1*VL(SRC), RNDKEYLAST, RNDKEYLAST1
- vpxord 2*VL(SRC), RNDKEYLAST, RNDKEYLAST2
- vpxord 3*VL(SRC), RNDKEYLAST, RNDKEYLAST3
- vaesenclast RNDKEYLAST0, V0, GHASHDATA0
- vaesenclast RNDKEYLAST1, V1, GHASHDATA1
- vaesenclast RNDKEYLAST2, V2, GHASHDATA2
- vaesenclast RNDKEYLAST3, V3, GHASHDATA3
- vmovdqu8 GHASHDATA0, 0*VL(DST)
- vmovdqu8 GHASHDATA1, 1*VL(DST)
- vmovdqu8 GHASHDATA2, 2*VL(DST)
- vmovdqu8 GHASHDATA3, 3*VL(DST)
+ _aesenclast_and_xor_4x
sub $-4*VL, SRC // shorter than 'add 4*VL' when VL=32
sub $-4*VL, DST
add $-4*VL, DATALEN
jl .Lghash_last_ciphertext_4x\@
.endif
// Cache as many additional AES round keys as possible.
-.irp i, 9,8,7,6,5
+.irp i, 9,8,7,6,5,4,3,2,1
vbroadcasti32x4 -\i*16(RNDKEYLAST_PTR), RNDKEY_M\i
.endr
.Lcrypt_loop_4x\@:
@@ -797,51 +807,18 @@
_vaesenc_4x RNDKEY
vbroadcasti32x4 -10*16(RNDKEYLAST_PTR), RNDKEY
_vaesenc_4x RNDKEY
128:
- // XOR the source data with the last round key, saving the result in
- // RNDKEYLAST[0-3]. This reduces latency by taking advantage of the
- // property vaesenclast(key, a) ^ b == vaesenclast(key ^ b, a).
-.if \enc
- vpxord 0*VL(SRC), RNDKEYLAST, RNDKEYLAST0
- vpxord 1*VL(SRC), RNDKEYLAST, RNDKEYLAST1
- vpxord 2*VL(SRC), RNDKEYLAST, RNDKEYLAST2
- vpxord 3*VL(SRC), RNDKEYLAST, RNDKEYLAST3
-.else
- vpxord GHASHDATA0, RNDKEYLAST, RNDKEYLAST0
- vpxord GHASHDATA1, RNDKEYLAST, RNDKEYLAST1
- vpxord GHASHDATA2, RNDKEYLAST, RNDKEYLAST2
- vpxord GHASHDATA3, RNDKEYLAST, RNDKEYLAST3
-.endif
-
// Finish the AES encryption of the counter blocks in V0-V3, interleaved
// with the GHASH update of the ciphertext blocks in GHASHDATA[0-3].
-.irp i, 9,8,7,6,5
+.irp i, 9,8,7,6,5,4,3,2,1
+ _ghash_step_4x (9 - \i)
_vaesenc_4x RNDKEY_M\i
- _ghash_step_4x (9 - \i)
-.endr
-.irp i, 4,3,2,1
- vbroadcasti32x4 -\i*16(RNDKEYLAST_PTR), RNDKEY
- _vaesenc_4x RNDKEY
- _ghash_step_4x (9 - \i)
.endr
_ghash_step_4x 9
-
- // Do the last AES round. This handles the XOR with the source data
- // too, as per the optimization described above.
- vaesenclast RNDKEYLAST0, V0, GHASHDATA0
- vaesenclast RNDKEYLAST1, V1, GHASHDATA1
- vaesenclast RNDKEYLAST2, V2, GHASHDATA2
- vaesenclast RNDKEYLAST3, V3, GHASHDATA3
-
- // Store the en/decrypted data to DST.
- vmovdqu8 GHASHDATA0, 0*VL(DST)
- vmovdqu8 GHASHDATA1, 1*VL(DST)
- vmovdqu8 GHASHDATA2, 2*VL(DST)
- vmovdqu8 GHASHDATA3, 3*VL(DST)
-
+ _aesenclast_and_xor_4x
sub $-4*VL, SRC // shorter than 'add 4*VL' when VL=32
sub $-4*VL, DST
add $-4*VL, DATALEN
jge .Lcrypt_loop_4x\@
@@ -938,11 +915,11 @@
// be whole block(s) that get processed by the GHASH multiplication and
// reduction instructions but should not actually be included in the
// GHASH. However, any such blocks are all-zeroes, and the values that
// they're multiplied with are also all-zeroes. Therefore they just add
// 0 * 0 = 0 to the final GHASH result, which makes no difference.
- vmovdqu8 (POWERS_PTR), H_POW1
+ vmovdqu8 (POWERS_PTR), H_POW1
.if \enc
vmovdqu8 V0, V1{%k1}{z}
.endif
vpshufb BSWAP_MASK, V1, V0
vpxord GHASH_ACC, V0, V0
--
2.47.1
