crypto: arm64/aes-ce-gcm - implement 2-way aggregation

Implement a faster version of the GHASH transform which amortizes
the reduction modulo the characteristic polynomial across two
input blocks at a time.

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@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/arch/arm64/crypto/ghash-ce-core.S b/arch/arm64/crypto/ghash-ce-core.S
index dac0df2..f7281e7 100644 (file)
--- a/arch/arm64/crypto/ghash-ce-core.S
+++ b/arch/arm64/crypto/ghash-ce-core.S
@@ -290,6 +290,10 @@ ENDPROC(pmull_ghash_update_p8)
        KS1             .req    v9
        INP0            .req    v10
        INP1            .req    v11
+       HH              .req    v12
+       XL2             .req    v13
+       XM2             .req    v14
+       XH2             .req    v15
 
        .macro          load_round_keys, rounds, rk
        cmp             \rounds, #12
@@ -323,6 +327,7 @@ ENDPROC(pmull_ghash_update_p8)
        .endm
 
        .macro          pmull_gcm_do_crypt, enc
+       ld1             {HH.2d}, [x4], #16
        ld1             {SHASH.2d}, [x4]
        ld1             {XL.2d}, [x1]
        ldr             x8, [x5, #8]                    // load lower counter
@@ -330,10 +335,11 @@ ENDPROC(pmull_ghash_update_p8)
        load_round_keys w7, x6
 
        movi            MASK.16b, #0xe1
-       ext             SHASH2.16b, SHASH.16b, SHASH.16b, #8
+       trn1            SHASH2.2d, SHASH.2d, HH.2d
+       trn2            T1.2d, SHASH.2d, HH.2d
 CPU_LE(        rev             x8, x8          )
        shl             MASK.2d, MASK.2d, #57
-       eor             SHASH2.16b, SHASH2.16b, SHASH.16b
+       eor             SHASH2.16b, SHASH2.16b, T1.16b
 
        .if             \enc == 1
        ldr             x10, [sp]
@@ -358,116 +364,82 @@ CPU_LE(  rev             x8, x8          )
        ins             KS0.d[1], x9                    // set lower counter
        ins             KS1.d[1], x11
 
-       rev64           T1.16b, INP0.16b
+       rev64           T1.16b, INP1.16b
 
        cmp             w7, #12
        b.ge            2f                              // AES-192/256?
 
 1:     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          XH2.1q, 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           XL2.1q, 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           XM2.1q, SHASH2.1d, 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
+       eor             T1.16b, T1.16b, XL.16b
 
        enc_round       KS1, v25
-
-       pmull           XL.1q, XL.1d, MASK.1d
-       eor             T2.16b, T2.16b, XH.16b
+       pmull2          XH.1q, HH.2d, XL.2d             // a1 * b1
 
        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, SHASH2.2d, 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             XL.16b, XL.16b, XL2.16b
+       eor             XH.16b, XH.16b, XH2.16b
 
        enc_round       KS1, v27
-
-       pmull2          XH.1q, SHASH.2d, XL.2d          // a1 * b1
-       eor             T1.16b, T1.16b, XL.16b
+       eor             XM.16b, XM.16b, XM2.16b
+       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 8ff6732..cd91b14 100644 (file)
--- a/arch/arm64/crypto/ghash-ce-glue.c
+++ b/arch/arm64/crypto/ghash-ce-glue.c
@@ -46,6 +46,7 @@ struct ghash_desc_ctx {
 
 struct gcm_aes_ctx {
        struct crypto_aes_ctx   aes_key;
+       u64                     h2[2];
        struct ghash_key        ghash_key;
 };
 
@@ -62,12 +63,11 @@ 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[],
@@ -232,7 +232,8 @@ 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);
@@ -244,7 +245,19 @@ 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 (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;
+
+       return 0;
 }
 
 static int gcm_setauthsize(struct crypto_aead *tfm, unsigned int authsize)
@@ -378,9 +391,8 @@ 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,
-                                         iv, ctx->aes_key.key_enc, nrounds,
-                                         ks);
+                                         walk.src.virt.addr, ctx->h2, iv,
+                                         ctx->aes_key.key_enc, nrounds, ks);
                        kernel_neon_end();
 
                        err = skcipher_walk_done(&walk,
@@ -486,8 +498,8 @@ 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,
-                                         iv, ctx->aes_key.key_enc, nrounds);
+                                         walk.src.virt.addr, ctx->h2, iv,
+                                         ctx->aes_key.key_enc, nrounds);
                        kernel_neon_end();
 
                        err = skcipher_walk_done(&walk,