forked from Minki/linux
crypto: arm/chacha20 - refactor to allow varying number of rounds
In preparation for adding XChaCha12 support, rename/refactor the NEON implementation of ChaCha20 to support different numbers of rounds. Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> 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
Herbert Xu
parent
d97a94309d
commit
3cc215198e
@ -9,7 +9,7 @@ obj-$(CONFIG_CRYPTO_SHA1_ARM) += sha1-arm.o
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obj-$(CONFIG_CRYPTO_SHA1_ARM_NEON) += sha1-arm-neon.o
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obj-$(CONFIG_CRYPTO_SHA256_ARM) += sha256-arm.o
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obj-$(CONFIG_CRYPTO_SHA512_ARM) += sha512-arm.o
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obj-$(CONFIG_CRYPTO_CHACHA20_NEON) += chacha20-neon.o
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obj-$(CONFIG_CRYPTO_CHACHA20_NEON) += chacha-neon.o
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ce-obj-$(CONFIG_CRYPTO_AES_ARM_CE) += aes-arm-ce.o
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ce-obj-$(CONFIG_CRYPTO_SHA1_ARM_CE) += sha1-arm-ce.o
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@ -52,7 +52,7 @@ aes-arm-ce-y := aes-ce-core.o aes-ce-glue.o
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ghash-arm-ce-y := ghash-ce-core.o ghash-ce-glue.o
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crct10dif-arm-ce-y := crct10dif-ce-core.o crct10dif-ce-glue.o
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crc32-arm-ce-y:= crc32-ce-core.o crc32-ce-glue.o
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chacha20-neon-y := chacha20-neon-core.o chacha20-neon-glue.o
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chacha-neon-y := chacha-neon-core.o chacha-neon-glue.o
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ifdef REGENERATE_ARM_CRYPTO
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quiet_cmd_perl = PERL $@
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@ -1,5 +1,5 @@
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/*
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* ChaCha20 256-bit cipher algorithm, RFC7539, ARM NEON functions
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* ChaCha/XChaCha NEON helper functions
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*
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* Copyright (C) 2016 Linaro, Ltd. <ard.biesheuvel@linaro.org>
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*
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@ -27,9 +27,9 @@
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* (d) vtbl.8 + vtbl.8 (multiple of 8 bits rotations only,
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* needs index vector)
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*
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* ChaCha20 has 16, 12, 8, and 7-bit rotations. For the 12 and 7-bit
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* rotations, the only choices are (a) and (b). We use (a) since it takes
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* two-thirds the cycles of (b) on both Cortex-A7 and Cortex-A53.
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* ChaCha has 16, 12, 8, and 7-bit rotations. For the 12 and 7-bit rotations,
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* the only choices are (a) and (b). We use (a) since it takes two-thirds the
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* cycles of (b) on both Cortex-A7 and Cortex-A53.
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*
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* For the 16-bit rotation, we use vrev32.16 since it's consistently fastest
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* and doesn't need a temporary register.
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@ -53,18 +53,19 @@
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.align 5
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/*
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* chacha20_permute - permute one block
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* chacha_permute - permute one block
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*
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* Permute one 64-byte block where the state matrix is stored in the four NEON
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* registers q0-q3. It performs matrix operations on four words in parallel,
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* but requires shuffling to rearrange the words after each round.
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*
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* The round count is given in r3.
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*
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* Clobbers: r3, ip, q4-q5
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*/
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chacha20_permute:
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chacha_permute:
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adr ip, .Lrol8_table
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mov r3, #10
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vld1.8 {d10}, [ip, :64]
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.Ldoubleround:
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@ -128,16 +129,17 @@ chacha20_permute:
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// x3 = shuffle32(x3, MASK(0, 3, 2, 1))
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vext.8 q3, q3, q3, #4
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subs r3, r3, #1
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subs r3, r3, #2
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bne .Ldoubleround
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bx lr
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ENDPROC(chacha20_permute)
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ENDPROC(chacha_permute)
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ENTRY(chacha20_block_xor_neon)
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ENTRY(chacha_block_xor_neon)
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// r0: Input state matrix, s
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// r1: 1 data block output, o
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// r2: 1 data block input, i
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// r3: nrounds
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push {lr}
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// x0..3 = s0..3
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@ -150,7 +152,7 @@ ENTRY(chacha20_block_xor_neon)
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vmov q10, q2
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vmov q11, q3
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bl chacha20_permute
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bl chacha_permute
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add ip, r2, #0x20
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vld1.8 {q4-q5}, [r2]
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@ -177,30 +179,32 @@ ENTRY(chacha20_block_xor_neon)
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vst1.8 {q2-q3}, [ip]
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pop {pc}
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ENDPROC(chacha20_block_xor_neon)
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ENDPROC(chacha_block_xor_neon)
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ENTRY(hchacha20_block_neon)
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ENTRY(hchacha_block_neon)
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// r0: Input state matrix, s
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// r1: output (8 32-bit words)
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// r2: nrounds
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push {lr}
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vld1.32 {q0-q1}, [r0]!
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vld1.32 {q2-q3}, [r0]
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bl chacha20_permute
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mov r3, r2
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bl chacha_permute
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vst1.32 {q0}, [r1]!
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vst1.32 {q3}, [r1]
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pop {pc}
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ENDPROC(hchacha20_block_neon)
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ENDPROC(hchacha_block_neon)
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.align 4
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.Lctrinc: .word 0, 1, 2, 3
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.Lrol8_table: .byte 3, 0, 1, 2, 7, 4, 5, 6
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.align 5
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ENTRY(chacha20_4block_xor_neon)
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ENTRY(chacha_4block_xor_neon)
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push {r4-r5}
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mov r4, sp // preserve the stack pointer
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sub ip, sp, #0x20 // allocate a 32 byte buffer
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@ -210,9 +214,10 @@ ENTRY(chacha20_4block_xor_neon)
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// r0: Input state matrix, s
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// r1: 4 data blocks output, o
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// r2: 4 data blocks input, i
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// r3: nrounds
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//
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// This function encrypts four consecutive ChaCha20 blocks by loading
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// This function encrypts four consecutive ChaCha blocks by loading
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// the state matrix in NEON registers four times. The algorithm performs
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// each operation on the corresponding word of each state matrix, hence
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// requires no word shuffling. The words are re-interleaved before the
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@ -245,7 +250,6 @@ ENTRY(chacha20_4block_xor_neon)
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vdup.32 q0, d0[0]
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adr ip, .Lrol8_table
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mov r3, #10
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b 1f
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.Ldoubleround4:
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@ -443,7 +447,7 @@ ENTRY(chacha20_4block_xor_neon)
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vsri.u32 q5, q8, #25
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vsri.u32 q6, q9, #25
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subs r3, r3, #1
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subs r3, r3, #2
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bne .Ldoubleround4
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// x0..7[0-3] are in q0-q7, x10..15[0-3] are in q10-q15.
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@ -553,4 +557,4 @@ ENTRY(chacha20_4block_xor_neon)
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pop {r4-r5}
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bx lr
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ENDPROC(chacha20_4block_xor_neon)
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ENDPROC(chacha_4block_xor_neon)
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@ -28,24 +28,26 @@
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#include <asm/neon.h>
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#include <asm/simd.h>
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asmlinkage void chacha20_block_xor_neon(u32 *state, u8 *dst, const u8 *src);
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asmlinkage void chacha20_4block_xor_neon(u32 *state, u8 *dst, const u8 *src);
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asmlinkage void hchacha20_block_neon(const u32 *state, u32 *out);
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asmlinkage void chacha_block_xor_neon(const u32 *state, u8 *dst, const u8 *src,
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int nrounds);
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asmlinkage void chacha_4block_xor_neon(const u32 *state, u8 *dst, const u8 *src,
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int nrounds);
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asmlinkage void hchacha_block_neon(const u32 *state, u32 *out, int nrounds);
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static void chacha20_doneon(u32 *state, u8 *dst, const u8 *src,
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unsigned int bytes)
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static void chacha_doneon(u32 *state, u8 *dst, const u8 *src,
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unsigned int bytes, int nrounds)
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{
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u8 buf[CHACHA_BLOCK_SIZE];
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while (bytes >= CHACHA_BLOCK_SIZE * 4) {
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chacha20_4block_xor_neon(state, dst, src);
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chacha_4block_xor_neon(state, dst, src, nrounds);
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bytes -= CHACHA_BLOCK_SIZE * 4;
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src += CHACHA_BLOCK_SIZE * 4;
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dst += CHACHA_BLOCK_SIZE * 4;
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state[12] += 4;
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}
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while (bytes >= CHACHA_BLOCK_SIZE) {
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chacha20_block_xor_neon(state, dst, src);
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chacha_block_xor_neon(state, dst, src, nrounds);
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bytes -= CHACHA_BLOCK_SIZE;
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src += CHACHA_BLOCK_SIZE;
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dst += CHACHA_BLOCK_SIZE;
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@ -53,13 +55,13 @@ static void chacha20_doneon(u32 *state, u8 *dst, const u8 *src,
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}
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if (bytes) {
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memcpy(buf, src, bytes);
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chacha20_block_xor_neon(state, buf, buf);
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chacha_block_xor_neon(state, buf, buf, nrounds);
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memcpy(dst, buf, bytes);
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}
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}
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static int chacha20_neon_stream_xor(struct skcipher_request *req,
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struct chacha_ctx *ctx, u8 *iv)
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static int chacha_neon_stream_xor(struct skcipher_request *req,
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struct chacha_ctx *ctx, u8 *iv)
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{
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struct skcipher_walk walk;
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u32 state[16];
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@ -76,8 +78,8 @@ static int chacha20_neon_stream_xor(struct skcipher_request *req,
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nbytes = round_down(nbytes, walk.stride);
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kernel_neon_begin();
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chacha20_doneon(state, walk.dst.virt.addr, walk.src.virt.addr,
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nbytes);
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chacha_doneon(state, walk.dst.virt.addr, walk.src.virt.addr,
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nbytes, ctx->nrounds);
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kernel_neon_end();
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err = skcipher_walk_done(&walk, walk.nbytes - nbytes);
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}
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@ -85,7 +87,7 @@ static int chacha20_neon_stream_xor(struct skcipher_request *req,
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return err;
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}
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static int chacha20_neon(struct skcipher_request *req)
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static int chacha_neon(struct skcipher_request *req)
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{
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struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
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struct chacha_ctx *ctx = crypto_skcipher_ctx(tfm);
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@ -93,10 +95,10 @@ static int chacha20_neon(struct skcipher_request *req)
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if (req->cryptlen <= CHACHA_BLOCK_SIZE || !may_use_simd())
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return crypto_chacha_crypt(req);
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return chacha20_neon_stream_xor(req, ctx, req->iv);
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return chacha_neon_stream_xor(req, ctx, req->iv);
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}
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static int xchacha20_neon(struct skcipher_request *req)
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static int xchacha_neon(struct skcipher_request *req)
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{
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struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
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struct chacha_ctx *ctx = crypto_skcipher_ctx(tfm);
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@ -110,12 +112,13 @@ static int xchacha20_neon(struct skcipher_request *req)
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crypto_chacha_init(state, ctx, req->iv);
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kernel_neon_begin();
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hchacha20_block_neon(state, subctx.key);
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hchacha_block_neon(state, subctx.key, ctx->nrounds);
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kernel_neon_end();
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subctx.nrounds = ctx->nrounds;
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memcpy(&real_iv[0], req->iv + 24, 8);
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memcpy(&real_iv[8], req->iv + 16, 8);
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return chacha20_neon_stream_xor(req, &subctx, real_iv);
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return chacha_neon_stream_xor(req, &subctx, real_iv);
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}
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static struct skcipher_alg algs[] = {
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@ -133,8 +136,8 @@ static struct skcipher_alg algs[] = {
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.chunksize = CHACHA_BLOCK_SIZE,
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.walksize = 4 * CHACHA_BLOCK_SIZE,
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.setkey = crypto_chacha20_setkey,
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.encrypt = chacha20_neon,
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.decrypt = chacha20_neon,
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.encrypt = chacha_neon,
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.decrypt = chacha_neon,
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}, {
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.base.cra_name = "xchacha20",
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.base.cra_driver_name = "xchacha20-neon",
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@ -149,12 +152,12 @@ static struct skcipher_alg algs[] = {
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.chunksize = CHACHA_BLOCK_SIZE,
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.walksize = 4 * CHACHA_BLOCK_SIZE,
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.setkey = crypto_chacha20_setkey,
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.encrypt = xchacha20_neon,
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.decrypt = xchacha20_neon,
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.encrypt = xchacha_neon,
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.decrypt = xchacha_neon,
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}
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};
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static int __init chacha20_simd_mod_init(void)
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static int __init chacha_simd_mod_init(void)
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{
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if (!(elf_hwcap & HWCAP_NEON))
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return -ENODEV;
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@ -162,14 +165,15 @@ static int __init chacha20_simd_mod_init(void)
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return crypto_register_skciphers(algs, ARRAY_SIZE(algs));
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}
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static void __exit chacha20_simd_mod_fini(void)
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static void __exit chacha_simd_mod_fini(void)
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{
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crypto_unregister_skciphers(algs, ARRAY_SIZE(algs));
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}
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module_init(chacha20_simd_mod_init);
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module_exit(chacha20_simd_mod_fini);
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module_init(chacha_simd_mod_init);
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module_exit(chacha_simd_mod_fini);
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MODULE_DESCRIPTION("ChaCha and XChaCha stream ciphers (NEON accelerated)");
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MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
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MODULE_LICENSE("GPL v2");
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MODULE_ALIAS_CRYPTO("chacha20");
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