Implement a faster version of the GHASH transform which amortizes the
reduction modulo the characteristic polynomial across two input blocks at
a time. This is based on the Intel white paper "Carry-Less Multiplication
Instruction and its Usage for Computing the GCM Mode"
On a Cortex-A53, the gcm(aes) performance increases 24%, from 3.0 cycles per
byte to 2.4 cpb for large input sizes.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
---
Raw numbers after the patch
arch/arm64/crypto/ghash-ce-core.S | 87 +++++++-------------
arch/arm64/crypto/ghash-ce-glue.c | 33 ++++++--
2 files changed, 54 insertions(+), 66 deletions(-)
diff --git a/arch/arm64/crypto/ghash-ce-core.S b/arch/arm64/crypto/ghash-ce-core.S
index 437a2fb0f7f9..c144b526abe6 100644
--- a/arch/arm64/crypto/ghash-ce-core.S
+++ b/arch/arm64/crypto/ghash-ce-core.S
@@ -290,6 +290,11 @@ ENDPROC(pmull_ghash_update_p8)
KS1 .req v9
INP0 .req v10
INP1 .req v11
+ HH .req v12
+ Hhl .req v13
+ XLn .req v14
+ XMn .req v15
+ XHn .req v16
.macro load_round_keys, rounds, rk
cmp \rounds, #12
@@ -342,13 +347,13 @@ CPU_LE( rev x28, x28 )
0: mov x0, x25
load_round_keys w26, x0
- ld1 {SHASH.2d}, [x23]
+ add x1, x23, #32
+ ld1 {HH.2d-Hhl.2d}, [x23]
+ ld1 {SHASH.2d}, [x1]
ld1 {XL.2d}, [x20]
movi MASK.16b, #0xe1
- ext SHASH2.16b, SHASH.16b, SHASH.16b, #8
shl MASK.2d, MASK.2d, #57
- eor SHASH2.16b, SHASH2.16b, SHASH.16b
.if \enc == 1
ld1 {KS0.16b-KS1.16b}, [x27]
@@ -372,116 +377,82 @@ CPU_LE( rev x28, x28 )
ins KS0.d[1], x9 // set lower counter
ins KS1.d[1], x10
- rev64 T1.16b, INP0.16b
+ rev64 T1.16b, INP1.16b
cmp w26, #12
b.ge 4f // AES-192/256?
2: enc_round KS0, v21
-
- ext T2.16b, XL.16b, XL.16b, #8
ext IN1.16b, T1.16b, T1.16b, #8
enc_round KS1, v21
-
- eor T1.16b, T1.16b, T2.16b
- eor XL.16b, XL.16b, IN1.16b
+ pmull2 XHn.1q, SHASH.2d, IN1.2d // a1 * b1
enc_round KS0, v22
-
- pmull2 XH.1q, SHASH.2d, XL.2d // a1 * b1
- eor T1.16b, T1.16b, XL.16b
+ eor T1.16b, T1.16b, IN1.16b
enc_round KS1, v22
-
- pmull XL.1q, SHASH.1d, XL.1d // a0 * b0
- pmull XM.1q, SHASH2.1d, T1.1d // (a1 + a0)(b1 + b0)
+ pmull XLn.1q, SHASH.1d, IN1.1d // a0 * b0
enc_round KS0, v23
-
- ext T1.16b, XL.16b, XH.16b, #8
- eor T2.16b, XL.16b, XH.16b
- eor XM.16b, XM.16b, T1.16b
+ pmull XMn.1q, Hhl.1d, T1.1d // (a1 + a0)(b1 + b0)
enc_round KS1, v23
-
- eor XM.16b, XM.16b, T2.16b
- pmull T2.1q, XL.1d, MASK.1d
+ rev64 T1.16b, INP0.16b
+ ext T2.16b, XL.16b, XL.16b, #8
enc_round KS0, v24
-
- mov XH.d[0], XM.d[1]
- mov XM.d[1], XL.d[0]
+ ext IN1.16b, T1.16b, T1.16b, #8
+ eor T1.16b, T1.16b, T2.16b
enc_round KS1, v24
-
- eor XL.16b, XM.16b, T2.16b
+ eor XL.16b, XL.16b, IN1.16b
enc_round KS0, v25
-
- ext T2.16b, XL.16b, XL.16b, #8
+ pmull2 XH.1q, HH.2d, XL.2d // a1 * b1
enc_round KS1, v25
-
- pmull XL.1q, XL.1d, MASK.1d
- eor T2.16b, T2.16b, XH.16b
+ eor T1.16b, T1.16b, XL.16b
enc_round KS0, v26
-
- eor XL.16b, XL.16b, T2.16b
- rev64 T1.16b, INP1.16b
+ pmull XL.1q, HH.1d, XL.1d // a0 * b0
enc_round KS1, v26
-
- ext T2.16b, XL.16b, XL.16b, #8
- ext IN1.16b, T1.16b, T1.16b, #8
+ pmull2 XM.1q, Hhl.2d, T1.2d // (a1 + a0)(b1 + b0)
enc_round KS0, v27
-
- eor T1.16b, T1.16b, T2.16b
- eor XL.16b, XL.16b, IN1.16b
+ eor XH.16b, XH.16b, XHn.16b
+ eor XM.16b, XM.16b, XMn.16b
enc_round KS1, v27
-
- pmull2 XH.1q, SHASH.2d, XL.2d // a1 * b1
- eor T1.16b, T1.16b, XL.16b
+ eor XL.16b, XL.16b, XLn.16b
+ ext T1.16b, XL.16b, XH.16b, #8
enc_round KS0, v28
-
- pmull XL.1q, SHASH.1d, XL.1d // a0 * b0
- pmull XM.1q, SHASH2.1d, T1.1d // (a1 + a0)(b1 + b0)
-
- enc_round KS1, v28
-
- ext T1.16b, XL.16b, XH.16b, #8
eor T2.16b, XL.16b, XH.16b
eor XM.16b, XM.16b, T1.16b
- enc_round KS0, v29
-
+ enc_round KS1, v28
eor XM.16b, XM.16b, T2.16b
+
+ enc_round KS0, v29
pmull T2.1q, XL.1d, MASK.1d
enc_round KS1, v29
-
mov XH.d[0], XM.d[1]
mov XM.d[1], XL.d[0]
aese KS0.16b, v30.16b
-
eor XL.16b, XM.16b, T2.16b
aese KS1.16b, v30.16b
-
ext T2.16b, XL.16b, XL.16b, #8
eor KS0.16b, KS0.16b, v31.16b
-
pmull XL.1q, XL.1d, MASK.1d
eor T2.16b, T2.16b, XH.16b
eor KS1.16b, KS1.16b, v31.16b
-
eor XL.16b, XL.16b, T2.16b
.if \enc == 0
diff --git a/arch/arm64/crypto/ghash-ce-glue.c b/arch/arm64/crypto/ghash-ce-glue.c
index 371f8368c196..65a0b8239620 100644
--- a/arch/arm64/crypto/ghash-ce-glue.c
+++ b/arch/arm64/crypto/ghash-ce-glue.c
@@ -46,6 +46,8 @@ struct ghash_desc_ctx {
struct gcm_aes_ctx {
struct crypto_aes_ctx aes_key;
+ u64 h2[2];
+ u64 hhl[2];
struct ghash_key ghash_key;
};
@@ -62,12 +64,11 @@ static void (*pmull_ghash_update)(int blocks, u64 dg[], const char *src,
const char *head);
asmlinkage void pmull_gcm_encrypt(int blocks, u64 dg[], u8 dst[],
- const u8 src[], struct ghash_key const *k,
- u8 ctr[], u32 const rk[], int rounds,
- u8 ks[]);
+ const u8 src[], u64 const *k, u8 ctr[],
+ u32 const rk[], int rounds, u8 ks[]);
asmlinkage void pmull_gcm_decrypt(int blocks, u64 dg[], u8 dst[],
- const u8 src[], struct ghash_key const *k,
+ const u8 src[], u64 const *k,
u8 ctr[], u32 const rk[], int rounds);
asmlinkage void pmull_gcm_encrypt_block(u8 dst[], u8 const src[],
@@ -233,7 +234,8 @@ static int gcm_setkey(struct crypto_aead *tfm, const u8 *inkey,
unsigned int keylen)
{
struct gcm_aes_ctx *ctx = crypto_aead_ctx(tfm);
- u8 key[GHASH_BLOCK_SIZE];
+ be128 h1, h2;
+ u8 *key = (u8 *)&h1;
int ret;
ret = crypto_aes_expand_key(&ctx->aes_key, inkey, keylen);
@@ -245,7 +247,22 @@ static int gcm_setkey(struct crypto_aead *tfm, const u8 *inkey,
__aes_arm64_encrypt(ctx->aes_key.key_enc, key, (u8[AES_BLOCK_SIZE]){},
num_rounds(&ctx->aes_key));
- return __ghash_setkey(&ctx->ghash_key, key, sizeof(key));
+ __ghash_setkey(&ctx->ghash_key, key, sizeof(be128));
+
+ /* calculate H^2 and Hhl (used for 2-way aggregation) */
+ h2 = h1;
+ gf128mul_lle(&h2, &h1);
+
+ ctx->h2[0] = (be64_to_cpu(h2.b) << 1) | (be64_to_cpu(h2.a) >> 63);
+ ctx->h2[1] = (be64_to_cpu(h2.a) << 1) | (be64_to_cpu(h2.b) >> 63);
+
+ if (be64_to_cpu(h2.a) >> 63)
+ ctx->h2[1] ^= 0xc200000000000000UL;
+
+ ctx->hhl[0] = ctx->ghash_key.a ^ ctx->ghash_key.b;
+ ctx->hhl[1] = ctx->h2[0] ^ ctx->h2[1];
+
+ return 0;
}
static int gcm_setauthsize(struct crypto_aead *tfm, unsigned int authsize)
@@ -381,7 +398,7 @@ static int gcm_encrypt(struct aead_request *req)
kernel_neon_begin();
pmull_gcm_encrypt(blocks, dg, walk.dst.virt.addr,
- walk.src.virt.addr, &ctx->ghash_key,
+ walk.src.virt.addr, ctx->h2,
iv, ctx->aes_key.key_enc,
num_rounds(&ctx->aes_key), ks);
kernel_neon_end();
@@ -490,7 +507,7 @@ static int gcm_decrypt(struct aead_request *req)
kernel_neon_begin();
pmull_gcm_decrypt(blocks, dg, walk.dst.virt.addr,
- walk.src.virt.addr, &ctx->ghash_key,
+ walk.src.virt.addr, ctx->h2,
iv, ctx->aes_key.key_enc, nrounds);
kernel_neon_end();
--
2.18.0
tcrypt performance numbers for a Cortex-A53 @ 1 GHz (CONFIG_PREEMPT disabled)
BASELINE:
=========
test 0 (128 bit key, 16 byte blocks): 445165 operations in 1 seconds ( 7122640 bytes)
test 1 (128 bit key, 64 byte blocks): 437076 operations in 1 seconds ( 27972864 bytes)
test 2 (128 bit key, 256 byte blocks): 354203 operations in 1 seconds ( 90675968 bytes)
test 3 (128 bit key, 512 byte blocks): 284031 operations in 1 seconds (145423872 bytes)
test 4 (128 bit key, 1024 byte blocks): 203473 operations in 1 seconds (208356352 bytes)
test 5 (128 bit key, 2048 byte blocks): 129855 operations in 1 seconds (265943040 bytes)
test 6 (128 bit key, 4096 byte blocks): 75686 operations in 1 seconds (310009856 bytes)
test 7 (128 bit key, 8192 byte blocks): 40167 operations in 1 seconds (329048064 bytes)
test 8 (192 bit key, 16 byte blocks): 441610 operations in 1 seconds ( 7065760 bytes)
test 9 (192 bit key, 64 byte blocks): 429364 operations in 1 seconds ( 27479296 bytes)
test 10 (192 bit key, 256 byte blocks): 343303 operations in 1 seconds ( 87885568 bytes)
test 11 (192 bit key, 512 byte blocks): 272029 operations in 1 seconds (139278848 bytes)
test 12 (192 bit key, 1024 byte blocks): 192399 operations in 1 seconds (197016576 bytes)
test 13 (192 bit key, 2048 byte blocks): 121298 operations in 1 seconds (248418304 bytes)
test 14 (192 bit key, 4096 byte blocks): 69994 operations in 1 seconds (286695424 bytes)
test 15 (192 bit key, 8192 byte blocks): 37045 operations in 1 seconds (303472640 bytes)
test 16 (256 bit key, 16 byte blocks): 438244 operations in 1 seconds ( 7011904 bytes)
test 17 (256 bit key, 64 byte blocks): 423345 operations in 1 seconds ( 27094080 bytes)
test 18 (256 bit key, 256 byte blocks): 336844 operations in 1 seconds ( 86232064 bytes)
test 19 (256 bit key, 512 byte blocks): 265711 operations in 1 seconds (136044032 bytes)
test 20 (256 bit key, 1024 byte blocks): 186853 operations in 1 seconds (191337472 bytes)
test 21 (256 bit key, 2048 byte blocks): 117301 operations in 1 seconds (240232448 bytes)
test 22 (256 bit key, 4096 byte blocks): 67513 operations in 1 seconds (276533248 bytes)
test 23 (256 bit key, 8192 byte blocks): 35629 operations in 1 seconds (291872768 bytes)
THIS PATCH:
===========
test 0 (128 bit key, 16 byte blocks): 441257 operations in 1 seconds ( 7060112 bytes)
test 1 (128 bit key, 64 byte blocks): 436595 operations in 1 seconds ( 27942080 bytes)
test 2 (128 bit key, 256 byte blocks): 369839 operations in 1 seconds ( 94678784 bytes)
test 3 (128 bit key, 512 byte blocks): 308239 operations in 1 seconds (157818368 bytes)
test 4 (128 bit key, 1024 byte blocks): 231004 operations in 1 seconds (236548096 bytes)
test 5 (128 bit key, 2048 byte blocks): 153930 operations in 1 seconds (315248640 bytes)
test 6 (128 bit key, 4096 byte blocks): 92739 operations in 1 seconds (379858944 bytes)
test 7 (128 bit key, 8192 byte blocks): 49934 operations in 1 seconds (409059328 bytes)
test 8 (192 bit key, 16 byte blocks): 437427 operations in 1 seconds ( 6998832 bytes)
test 9 (192 bit key, 64 byte blocks): 429462 operations in 1 seconds ( 27485568 bytes)
test 10 (192 bit key, 256 byte blocks): 358183 operations in 1 seconds ( 91694848 bytes)
test 11 (192 bit key, 512 byte blocks): 294539 operations in 1 seconds (150803968 bytes)
test 12 (192 bit key, 1024 byte blocks): 217082 operations in 1 seconds (222291968 bytes)
test 13 (192 bit key, 2048 byte blocks): 140672 operations in 1 seconds (288096256 bytes)
test 14 (192 bit key, 4096 byte blocks): 84369 operations in 1 seconds (345575424 bytes)
test 15 (192 bit key, 8192 byte blocks): 45280 operations in 1 seconds (370933760 bytes)
test 16 (256 bit key, 16 byte blocks): 434127 operations in 1 seconds ( 6946032 bytes)
test 17 (256 bit key, 64 byte blocks): 423837 operations in 1 seconds ( 27125568 bytes)
test 18 (256 bit key, 256 byte blocks): 351244 operations in 1 seconds ( 89918464 bytes)
test 19 (256 bit key, 512 byte blocks): 286884 operations in 1 seconds (146884608 bytes)
test 20 (256 bit key, 1024 byte blocks): 209954 operations in 1 seconds (214992896 bytes)
test 21 (256 bit key, 2048 byte blocks): 136553 operations in 1 seconds (279660544 bytes)
test 22 (256 bit key, 4096 byte blocks): 80749 operations in 1 seconds (330747904 bytes)
test 23 (256 bit key, 8192 byte blocks): 43118 operations in 1 seconds (353222656 bytes)
