[PATCH v2 2/3] crypto: arm64/chacha20 - implement NEON version based on SSE3 code
Ard Biesheuvel
ard.biesheuvel at linaro.org
Fri Dec 9 06:33:52 PST 2016
This is a straight port to arm64/NEON of the x86 SSE3 implementation
of the ChaCha20 stream cipher.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel at linaro.org>
---
arch/arm64/crypto/Kconfig | 6 +
arch/arm64/crypto/Makefile | 3 +
arch/arm64/crypto/chacha20-neon-core.S | 450 ++++++++++++++++++++
arch/arm64/crypto/chacha20-neon-glue.c | 122 ++++++
4 files changed, 581 insertions(+)
diff --git a/arch/arm64/crypto/Kconfig b/arch/arm64/crypto/Kconfig
index 450a85df041a..0bf0f531f539 100644
--- a/arch/arm64/crypto/Kconfig
+++ b/arch/arm64/crypto/Kconfig
@@ -72,4 +72,10 @@ config CRYPTO_CRC32_ARM64
depends on ARM64
select CRYPTO_HASH
+config CRYPTO_CHACHA20_NEON
+ tristate "NEON accelerated ChaCha20 symmetric cipher"
+ depends on KERNEL_MODE_NEON
+ select CRYPTO_BLKCIPHER
+ select CRYPTO_CHACHA20
+
endif
diff --git a/arch/arm64/crypto/Makefile b/arch/arm64/crypto/Makefile
index aa8888d7b744..9d2826c5fccf 100644
--- a/arch/arm64/crypto/Makefile
+++ b/arch/arm64/crypto/Makefile
@@ -41,6 +41,9 @@ sha256-arm64-y := sha256-glue.o sha256-core.o
obj-$(CONFIG_CRYPTO_SHA512_ARM64) += sha512-arm64.o
sha512-arm64-y := sha512-glue.o sha512-core.o
+obj-$(CONFIG_CRYPTO_CHACHA20_NEON) += chacha20-neon.o
+chacha20-neon-y := chacha20-neon-core.o chacha20-neon-glue.o
+
AFLAGS_aes-ce.o := -DINTERLEAVE=4
AFLAGS_aes-neon.o := -DINTERLEAVE=4
diff --git a/arch/arm64/crypto/chacha20-neon-core.S b/arch/arm64/crypto/chacha20-neon-core.S
new file mode 100644
index 000000000000..3cbbf23dc4d2
--- /dev/null
+++ b/arch/arm64/crypto/chacha20-neon-core.S
@@ -0,0 +1,450 @@
+/*
+ * ChaCha20 256-bit cipher algorithm, RFC7539, arm64 NEON functions
+ *
+ * Copyright (C) 2016 Linaro, Ltd. <ard.biesheuvel at linaro.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * Based on:
+ * ChaCha20 256-bit cipher algorithm, RFC7539, x64 SSSE3 functions
+ *
+ * Copyright (C) 2015 Martin Willi
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/linkage.h>
+
+ .text
+ .align 6
+
+ENTRY(chacha20_block_xor_neon)
+ // x0: Input state matrix, s
+ // x1: 1 data block output, o
+ // x2: 1 data block input, i
+
+ //
+ // This function encrypts one ChaCha20 block by loading the state matrix
+ // in four NEON registers. It performs matrix operation on four words in
+ // parallel, but requires shuffling to rearrange the words after each
+ // round.
+ //
+
+ // x0..3 = s0..3
+ adr x3, ROT8
+ ld1 {v0.4s-v3.4s}, [x0]
+ ld1 {v8.4s-v11.4s}, [x0]
+ ld1 {v12.4s}, [x3]
+
+ mov x3, #10
+
+.Ldoubleround:
+ // x0 += x1, x3 = rotl32(x3 ^ x0, 16)
+ add v0.4s, v0.4s, v1.4s
+ eor v3.16b, v3.16b, v0.16b
+ rev32 v3.8h, v3.8h
+
+ // x2 += x3, x1 = rotl32(x1 ^ x2, 12)
+ add v2.4s, v2.4s, v3.4s
+ eor v4.16b, v1.16b, v2.16b
+ shl v1.4s, v4.4s, #12
+ sri v1.4s, v4.4s, #20
+
+ // x0 += x1, x3 = rotl32(x3 ^ x0, 8)
+ add v0.4s, v0.4s, v1.4s
+ eor v3.16b, v3.16b, v0.16b
+ tbl v3.16b, {v3.16b}, v12.16b
+
+ // x2 += x3, x1 = rotl32(x1 ^ x2, 7)
+ add v2.4s, v2.4s, v3.4s
+ eor v4.16b, v1.16b, v2.16b
+ shl v1.4s, v4.4s, #7
+ sri v1.4s, v4.4s, #25
+
+ // x1 = shuffle32(x1, MASK(0, 3, 2, 1))
+ ext v1.16b, v1.16b, v1.16b, #4
+ // x2 = shuffle32(x2, MASK(1, 0, 3, 2))
+ ext v2.16b, v2.16b, v2.16b, #8
+ // x3 = shuffle32(x3, MASK(2, 1, 0, 3))
+ ext v3.16b, v3.16b, v3.16b, #12
+
+ // x0 += x1, x3 = rotl32(x3 ^ x0, 16)
+ add v0.4s, v0.4s, v1.4s
+ eor v3.16b, v3.16b, v0.16b
+ rev32 v3.8h, v3.8h
+
+ // x2 += x3, x1 = rotl32(x1 ^ x2, 12)
+ add v2.4s, v2.4s, v3.4s
+ eor v4.16b, v1.16b, v2.16b
+ shl v1.4s, v4.4s, #12
+ sri v1.4s, v4.4s, #20
+
+ // x0 += x1, x3 = rotl32(x3 ^ x0, 8)
+ add v0.4s, v0.4s, v1.4s
+ eor v3.16b, v3.16b, v0.16b
+ tbl v3.16b, {v3.16b}, v12.16b
+
+ // x2 += x3, x1 = rotl32(x1 ^ x2, 7)
+ add v2.4s, v2.4s, v3.4s
+ eor v4.16b, v1.16b, v2.16b
+ shl v1.4s, v4.4s, #7
+ sri v1.4s, v4.4s, #25
+
+ // x1 = shuffle32(x1, MASK(2, 1, 0, 3))
+ ext v1.16b, v1.16b, v1.16b, #12
+ // x2 = shuffle32(x2, MASK(1, 0, 3, 2))
+ ext v2.16b, v2.16b, v2.16b, #8
+ // x3 = shuffle32(x3, MASK(0, 3, 2, 1))
+ ext v3.16b, v3.16b, v3.16b, #4
+
+ subs x3, x3, #1
+ b.ne .Ldoubleround
+
+ ld1 {v4.16b-v7.16b}, [x2]
+
+ // o0 = i0 ^ (x0 + s0)
+ add v0.4s, v0.4s, v8.4s
+ eor v0.16b, v0.16b, v4.16b
+
+ // o1 = i1 ^ (x1 + s1)
+ add v1.4s, v1.4s, v9.4s
+ eor v1.16b, v1.16b, v5.16b
+
+ // o2 = i2 ^ (x2 + s2)
+ add v2.4s, v2.4s, v10.4s
+ eor v2.16b, v2.16b, v6.16b
+
+ // o3 = i3 ^ (x3 + s3)
+ add v3.4s, v3.4s, v11.4s
+ eor v3.16b, v3.16b, v7.16b
+
+ st1 {v0.16b-v3.16b}, [x1]
+
+ ret
+ENDPROC(chacha20_block_xor_neon)
+
+ .align 6
+ENTRY(chacha20_4block_xor_neon)
+ // x0: Input state matrix, s
+ // x1: 4 data blocks output, o
+ // x2: 4 data blocks input, i
+
+ //
+ // This function encrypts four consecutive ChaCha20 blocks by loading
+ // the state matrix in NEON registers four times. The algorithm performs
+ // each operation on the corresponding word of each state matrix, hence
+ // requires no word shuffling. For final XORing step we transpose the
+ // matrix by interleaving 32- and then 64-bit words, which allows us to
+ // do XOR in NEON registers.
+ //
+ adr x3, CTRINC // ... and ROT8
+ ld1 {v30.4s-v31.4s}, [x3]
+
+ // x0..15[0-3] = s0..3[0..3]
+ mov x4, x0
+ ld4r { v0.4s- v3.4s}, [x4], #16
+ ld4r { v4.4s- v7.4s}, [x4], #16
+ ld4r { v8.4s-v11.4s}, [x4], #16
+ ld4r {v12.4s-v15.4s}, [x4]
+
+ // x12 += counter values 0-3
+ add v12.4s, v12.4s, v30.4s
+
+ mov x3, #10
+
+.Ldoubleround4:
+ // x0 += x4, x12 = rotl32(x12 ^ x0, 16)
+ // x1 += x5, x13 = rotl32(x13 ^ x1, 16)
+ // x2 += x6, x14 = rotl32(x14 ^ x2, 16)
+ // x3 += x7, x15 = rotl32(x15 ^ x3, 16)
+ add v0.4s, v0.4s, v4.4s
+ add v1.4s, v1.4s, v5.4s
+ add v2.4s, v2.4s, v6.4s
+ add v3.4s, v3.4s, v7.4s
+
+ eor v12.16b, v12.16b, v0.16b
+ eor v13.16b, v13.16b, v1.16b
+ eor v14.16b, v14.16b, v2.16b
+ eor v15.16b, v15.16b, v3.16b
+
+ rev32 v12.8h, v12.8h
+ rev32 v13.8h, v13.8h
+ rev32 v14.8h, v14.8h
+ rev32 v15.8h, v15.8h
+
+ // x8 += x12, x4 = rotl32(x4 ^ x8, 12)
+ // x9 += x13, x5 = rotl32(x5 ^ x9, 12)
+ // x10 += x14, x6 = rotl32(x6 ^ x10, 12)
+ // x11 += x15, x7 = rotl32(x7 ^ x11, 12)
+ add v8.4s, v8.4s, v12.4s
+ add v9.4s, v9.4s, v13.4s
+ add v10.4s, v10.4s, v14.4s
+ add v11.4s, v11.4s, v15.4s
+
+ eor v18.16b, v4.16b, v8.16b
+ eor v19.16b, v5.16b, v9.16b
+ eor v20.16b, v6.16b, v10.16b
+ eor v21.16b, v7.16b, v11.16b
+
+ shl v4.4s, v18.4s, #12
+ shl v5.4s, v19.4s, #12
+ shl v6.4s, v20.4s, #12
+ shl v7.4s, v21.4s, #12
+
+ sri v4.4s, v18.4s, #20
+ sri v5.4s, v19.4s, #20
+ sri v6.4s, v20.4s, #20
+ sri v7.4s, v21.4s, #20
+
+ // x0 += x4, x12 = rotl32(x12 ^ x0, 8)
+ // x1 += x5, x13 = rotl32(x13 ^ x1, 8)
+ // x2 += x6, x14 = rotl32(x14 ^ x2, 8)
+ // x3 += x7, x15 = rotl32(x15 ^ x3, 8)
+ add v0.4s, v0.4s, v4.4s
+ add v1.4s, v1.4s, v5.4s
+ add v2.4s, v2.4s, v6.4s
+ add v3.4s, v3.4s, v7.4s
+
+ eor v12.16b, v12.16b, v0.16b
+ eor v13.16b, v13.16b, v1.16b
+ eor v14.16b, v14.16b, v2.16b
+ eor v15.16b, v15.16b, v3.16b
+
+ tbl v12.16b, {v12.16b}, v31.16b
+ tbl v13.16b, {v13.16b}, v31.16b
+ tbl v14.16b, {v14.16b}, v31.16b
+ tbl v15.16b, {v15.16b}, v31.16b
+
+ // x8 += x12, x4 = rotl32(x4 ^ x8, 7)
+ // x9 += x13, x5 = rotl32(x5 ^ x9, 7)
+ // x10 += x14, x6 = rotl32(x6 ^ x10, 7)
+ // x11 += x15, x7 = rotl32(x7 ^ x11, 7)
+ add v8.4s, v8.4s, v12.4s
+ add v9.4s, v9.4s, v13.4s
+ add v10.4s, v10.4s, v14.4s
+ add v11.4s, v11.4s, v15.4s
+
+ eor v18.16b, v4.16b, v8.16b
+ eor v19.16b, v5.16b, v9.16b
+ eor v20.16b, v6.16b, v10.16b
+ eor v21.16b, v7.16b, v11.16b
+
+ shl v4.4s, v18.4s, #7
+ shl v5.4s, v19.4s, #7
+ shl v6.4s, v20.4s, #7
+ shl v7.4s, v21.4s, #7
+
+ sri v4.4s, v18.4s, #25
+ sri v5.4s, v19.4s, #25
+ sri v6.4s, v20.4s, #25
+ sri v7.4s, v21.4s, #25
+
+ // x0 += x5, x15 = rotl32(x15 ^ x0, 16)
+ // x1 += x6, x12 = rotl32(x12 ^ x1, 16)
+ // x2 += x7, x13 = rotl32(x13 ^ x2, 16)
+ // x3 += x4, x14 = rotl32(x14 ^ x3, 16)
+ add v0.4s, v0.4s, v5.4s
+ add v1.4s, v1.4s, v6.4s
+ add v2.4s, v2.4s, v7.4s
+ add v3.4s, v3.4s, v4.4s
+
+ eor v15.16b, v15.16b, v0.16b
+ eor v12.16b, v12.16b, v1.16b
+ eor v13.16b, v13.16b, v2.16b
+ eor v14.16b, v14.16b, v3.16b
+
+ rev32 v15.8h, v15.8h
+ rev32 v12.8h, v12.8h
+ rev32 v13.8h, v13.8h
+ rev32 v14.8h, v14.8h
+
+ // x10 += x15, x5 = rotl32(x5 ^ x10, 12)
+ // x11 += x12, x6 = rotl32(x6 ^ x11, 12)
+ // x8 += x13, x7 = rotl32(x7 ^ x8, 12)
+ // x9 += x14, x4 = rotl32(x4 ^ x9, 12)
+ add v10.4s, v10.4s, v15.4s
+ add v11.4s, v11.4s, v12.4s
+ add v8.4s, v8.4s, v13.4s
+ add v9.4s, v9.4s, v14.4s
+
+ eor v18.16b, v5.16b, v10.16b
+ eor v19.16b, v6.16b, v11.16b
+ eor v20.16b, v7.16b, v8.16b
+ eor v21.16b, v4.16b, v9.16b
+
+ shl v5.4s, v18.4s, #12
+ shl v6.4s, v19.4s, #12
+ shl v7.4s, v20.4s, #12
+ shl v4.4s, v21.4s, #12
+
+ sri v5.4s, v18.4s, #20
+ sri v6.4s, v19.4s, #20
+ sri v7.4s, v20.4s, #20
+ sri v4.4s, v21.4s, #20
+
+ // x0 += x5, x15 = rotl32(x15 ^ x0, 8)
+ // x1 += x6, x12 = rotl32(x12 ^ x1, 8)
+ // x2 += x7, x13 = rotl32(x13 ^ x2, 8)
+ // x3 += x4, x14 = rotl32(x14 ^ x3, 8)
+ add v0.4s, v0.4s, v5.4s
+ add v1.4s, v1.4s, v6.4s
+ add v2.4s, v2.4s, v7.4s
+ add v3.4s, v3.4s, v4.4s
+
+ eor v15.16b, v15.16b, v0.16b
+ eor v12.16b, v12.16b, v1.16b
+ eor v13.16b, v13.16b, v2.16b
+ eor v14.16b, v14.16b, v3.16b
+
+ tbl v15.16b, {v15.16b}, v31.16b
+ tbl v12.16b, {v12.16b}, v31.16b
+ tbl v13.16b, {v13.16b}, v31.16b
+ tbl v14.16b, {v14.16b}, v31.16b
+
+ // x10 += x15, x5 = rotl32(x5 ^ x10, 7)
+ // x11 += x12, x6 = rotl32(x6 ^ x11, 7)
+ // x8 += x13, x7 = rotl32(x7 ^ x8, 7)
+ // x9 += x14, x4 = rotl32(x4 ^ x9, 7)
+ add v10.4s, v10.4s, v15.4s
+ add v11.4s, v11.4s, v12.4s
+ add v8.4s, v8.4s, v13.4s
+ add v9.4s, v9.4s, v14.4s
+
+ eor v18.16b, v5.16b, v10.16b
+ eor v19.16b, v6.16b, v11.16b
+ eor v20.16b, v7.16b, v8.16b
+ eor v21.16b, v4.16b, v9.16b
+
+ shl v5.4s, v18.4s, #7
+ shl v6.4s, v19.4s, #7
+ shl v7.4s, v20.4s, #7
+ shl v4.4s, v21.4s, #7
+
+ sri v5.4s, v18.4s, #25
+ sri v6.4s, v19.4s, #25
+ sri v7.4s, v20.4s, #25
+ sri v4.4s, v21.4s, #25
+
+ subs x3, x3, #1
+ b.ne .Ldoubleround4
+
+ ld4r {v16.4s-v19.4s}, [x0], #16
+ ld4r {v20.4s-v23.4s}, [x0], #16
+
+ // x12 += counter values 0-3
+ add v12.4s, v12.4s, v30.4s
+
+ // x0[0-3] += s0[0]
+ // x1[0-3] += s0[1]
+ // x2[0-3] += s0[2]
+ // x3[0-3] += s0[3]
+ add v0.4s, v0.4s, v16.4s
+ add v1.4s, v1.4s, v17.4s
+ add v2.4s, v2.4s, v18.4s
+ add v3.4s, v3.4s, v19.4s
+
+ ld4r {v24.4s-v27.4s}, [x0], #16
+ ld4r {v28.4s-v31.4s}, [x0]
+
+ // x4[0-3] += s1[0]
+ // x5[0-3] += s1[1]
+ // x6[0-3] += s1[2]
+ // x7[0-3] += s1[3]
+ add v4.4s, v4.4s, v20.4s
+ add v5.4s, v5.4s, v21.4s
+ add v6.4s, v6.4s, v22.4s
+ add v7.4s, v7.4s, v23.4s
+
+ // x8[0-3] += s2[0]
+ // x9[0-3] += s2[1]
+ // x10[0-3] += s2[2]
+ // x11[0-3] += s2[3]
+ add v8.4s, v8.4s, v24.4s
+ add v9.4s, v9.4s, v25.4s
+ add v10.4s, v10.4s, v26.4s
+ add v11.4s, v11.4s, v27.4s
+
+ // x12[0-3] += s3[0]
+ // x13[0-3] += s3[1]
+ // x14[0-3] += s3[2]
+ // x15[0-3] += s3[3]
+ add v12.4s, v12.4s, v28.4s
+ add v13.4s, v13.4s, v29.4s
+ add v14.4s, v14.4s, v30.4s
+ add v15.4s, v15.4s, v31.4s
+
+ // interleave 32-bit words in state n, n+1
+ zip1 v16.4s, v0.4s, v1.4s
+ zip2 v17.4s, v0.4s, v1.4s
+ zip1 v18.4s, v2.4s, v3.4s
+ zip2 v19.4s, v2.4s, v3.4s
+ zip1 v20.4s, v4.4s, v5.4s
+ zip2 v21.4s, v4.4s, v5.4s
+ zip1 v22.4s, v6.4s, v7.4s
+ zip2 v23.4s, v6.4s, v7.4s
+ zip1 v24.4s, v8.4s, v9.4s
+ zip2 v25.4s, v8.4s, v9.4s
+ zip1 v26.4s, v10.4s, v11.4s
+ zip2 v27.4s, v10.4s, v11.4s
+ zip1 v28.4s, v12.4s, v13.4s
+ zip2 v29.4s, v12.4s, v13.4s
+ zip1 v30.4s, v14.4s, v15.4s
+ zip2 v31.4s, v14.4s, v15.4s
+
+ // interleave 64-bit words in state n, n+2
+ zip1 v0.2d, v16.2d, v18.2d
+ zip2 v4.2d, v16.2d, v18.2d
+ zip1 v8.2d, v17.2d, v19.2d
+ zip2 v12.2d, v17.2d, v19.2d
+ ld1 {v16.16b-v19.16b}, [x2], #64
+
+ zip1 v1.2d, v20.2d, v22.2d
+ zip2 v5.2d, v20.2d, v22.2d
+ zip1 v9.2d, v21.2d, v23.2d
+ zip2 v13.2d, v21.2d, v23.2d
+ ld1 {v20.16b-v23.16b}, [x2], #64
+
+ zip1 v2.2d, v24.2d, v26.2d
+ zip2 v6.2d, v24.2d, v26.2d
+ zip1 v10.2d, v25.2d, v27.2d
+ zip2 v14.2d, v25.2d, v27.2d
+ ld1 {v24.16b-v27.16b}, [x2], #64
+
+ zip1 v3.2d, v28.2d, v30.2d
+ zip2 v7.2d, v28.2d, v30.2d
+ zip1 v11.2d, v29.2d, v31.2d
+ zip2 v15.2d, v29.2d, v31.2d
+ ld1 {v28.16b-v31.16b}, [x2]
+
+ // xor with corresponding input, write to output
+ eor v16.16b, v16.16b, v0.16b
+ eor v17.16b, v17.16b, v1.16b
+ eor v18.16b, v18.16b, v2.16b
+ eor v19.16b, v19.16b, v3.16b
+ eor v20.16b, v20.16b, v4.16b
+ eor v21.16b, v21.16b, v5.16b
+ st1 {v16.16b-v19.16b}, [x1], #64
+ eor v22.16b, v22.16b, v6.16b
+ eor v23.16b, v23.16b, v7.16b
+ eor v24.16b, v24.16b, v8.16b
+ eor v25.16b, v25.16b, v9.16b
+ st1 {v20.16b-v23.16b}, [x1], #64
+ eor v26.16b, v26.16b, v10.16b
+ eor v27.16b, v27.16b, v11.16b
+ eor v28.16b, v28.16b, v12.16b
+ st1 {v24.16b-v27.16b}, [x1], #64
+ eor v29.16b, v29.16b, v13.16b
+ eor v30.16b, v30.16b, v14.16b
+ eor v31.16b, v31.16b, v15.16b
+ st1 {v28.16b-v31.16b}, [x1]
+
+ ret
+ENDPROC(chacha20_4block_xor_neon)
+
+CTRINC: .word 0, 1, 2, 3
+ROT8: .word 0x02010003, 0x06050407, 0x0a09080b, 0x0e0d0c0f
diff --git a/arch/arm64/crypto/chacha20-neon-glue.c b/arch/arm64/crypto/chacha20-neon-glue.c
new file mode 100644
index 000000000000..06fdb8468ac6
--- /dev/null
+++ b/arch/arm64/crypto/chacha20-neon-glue.c
@@ -0,0 +1,122 @@
+/*
+ * ChaCha20 256-bit cipher algorithm, RFC7539, arm64 NEON functions
+ *
+ * Copyright (C) 2016 Linaro, Ltd. <ard.biesheuvel at linaro.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * Based on:
+ * ChaCha20 256-bit cipher algorithm, RFC7539, SIMD glue code
+ *
+ * Copyright (C) 2015 Martin Willi
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <crypto/algapi.h>
+#include <crypto/chacha20.h>
+#include <crypto/internal/skcipher.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+
+#include <asm/neon.h>
+
+asmlinkage void chacha20_block_xor_neon(u32 *state, u8 *dst, const u8 *src);
+asmlinkage void chacha20_4block_xor_neon(u32 *state, u8 *dst, const u8 *src);
+
+static void chacha20_doneon(u32 *state, u8 *dst, const u8 *src,
+ unsigned int bytes)
+{
+ u8 buf[CHACHA20_BLOCK_SIZE];
+
+ while (bytes >= CHACHA20_BLOCK_SIZE * 4) {
+ chacha20_4block_xor_neon(state, dst, src);
+ bytes -= CHACHA20_BLOCK_SIZE * 4;
+ src += CHACHA20_BLOCK_SIZE * 4;
+ dst += CHACHA20_BLOCK_SIZE * 4;
+ state[12] += 4;
+ }
+ while (bytes >= CHACHA20_BLOCK_SIZE) {
+ chacha20_block_xor_neon(state, dst, src);
+ bytes -= CHACHA20_BLOCK_SIZE;
+ src += CHACHA20_BLOCK_SIZE;
+ dst += CHACHA20_BLOCK_SIZE;
+ state[12]++;
+ }
+ if (bytes) {
+ memcpy(buf, src, bytes);
+ chacha20_block_xor_neon(state, buf, buf);
+ memcpy(dst, buf, bytes);
+ }
+}
+
+static int chacha20_neon(struct skcipher_request *req)
+{
+ struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
+ struct chacha20_ctx *ctx = crypto_skcipher_ctx(tfm);
+ struct skcipher_walk walk;
+ u32 state[16];
+ int err;
+
+ if (req->cryptlen <= CHACHA20_BLOCK_SIZE)
+ return crypto_chacha20_crypt(req);
+
+ err = skcipher_walk_virt(&walk, req, true);
+
+ crypto_chacha20_init(state, ctx, walk.iv);
+
+ kernel_neon_begin();
+ while (walk.nbytes > 0) {
+ unsigned int nbytes = walk.nbytes;
+
+ if (nbytes < walk.total)
+ nbytes = round_down(nbytes, walk.chunksize);
+
+ chacha20_doneon(state, walk.dst.virt.addr, walk.src.virt.addr,
+ nbytes);
+ err = skcipher_walk_done(&walk, walk.nbytes - nbytes);
+ }
+ kernel_neon_end();
+
+ return err;
+}
+
+static struct skcipher_alg alg = {
+ .base.cra_name = "chacha20",
+ .base.cra_driver_name = "chacha20-neon",
+ .base.cra_priority = 300,
+ .base.cra_blocksize = 1,
+ .base.cra_ctxsize = sizeof(struct chacha20_ctx),
+ .base.cra_alignmask = 1,
+ .base.cra_module = THIS_MODULE,
+
+ .min_keysize = CHACHA20_KEY_SIZE,
+ .max_keysize = CHACHA20_KEY_SIZE,
+ .ivsize = CHACHA20_IV_SIZE,
+ .chunksize = 4 * CHACHA20_BLOCK_SIZE,
+ .setkey = crypto_chacha20_setkey,
+ .encrypt = chacha20_neon,
+ .decrypt = chacha20_neon,
+};
+
+static int __init chacha20_simd_mod_init(void)
+{
+ return crypto_register_skcipher(&alg);
+}
+
+static void __exit chacha20_simd_mod_fini(void)
+{
+ crypto_unregister_skcipher(&alg);
+}
+
+module_init(chacha20_simd_mod_init);
+module_exit(chacha20_simd_mod_fini);
+
+MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel at linaro.org>");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS_CRYPTO("chacha20");
--
2.7.4
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