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crypto: arm64/chacha20 - add XChaCha20 support
Add an XChaCha20 implementation that is hooked up to the ARM64 NEON implementation of ChaCha20. This can be used by Adiantum. A NEON implementation of single-block HChaCha20 is also added so that XChaCha20 can use it rather than the generic implementation. This required refactoring the ChaCha20 permutation into its own function. Signed-off-by: Eric Biggers <ebiggers@google.com> Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Eric Biggers
Herbert Xu
parent
a00fa0c887
commit
cc7cf991e9
@ -101,7 +101,7 @@ config CRYPTO_AES_ARM64_NEON_BLK
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select CRYPTO_SIMD
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config CRYPTO_CHACHA20_NEON
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tristate "NEON accelerated ChaCha20 symmetric cipher"
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tristate "ChaCha20 and XChaCha20 stream ciphers using NEON instructions"
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depends on KERNEL_MODE_NEON
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select CRYPTO_BLKCIPHER
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select CRYPTO_CHACHA20
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@ -23,25 +23,20 @@
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.text
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.align 6
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ENTRY(chacha20_block_xor_neon)
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// x0: Input state matrix, s
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// x1: 1 data block output, o
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// x2: 1 data block input, i
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//
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// This function encrypts one ChaCha20 block by loading the state matrix
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// in four NEON registers. It performs matrix operation on four words in
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// parallel, but requires shuffling to rearrange the words after each
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// round.
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//
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// x0..3 = s0..3
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adr x3, ROT8
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ld1 {v0.4s-v3.4s}, [x0]
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ld1 {v8.4s-v11.4s}, [x0]
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ld1 {v12.4s}, [x3]
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/*
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* chacha20_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 v0-v3. 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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* Clobbers: x3, x10, v4, v12
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*/
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chacha20_permute:
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mov x3, #10
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adr x10, ROT8
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ld1 {v12.4s}, [x10]
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.Ldoubleround:
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// x0 += x1, x3 = rotl32(x3 ^ x0, 16)
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@ -105,6 +100,23 @@ ENTRY(chacha20_block_xor_neon)
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subs x3, x3, #1
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b.ne .Ldoubleround
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ret
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ENDPROC(chacha20_permute)
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ENTRY(chacha20_block_xor_neon)
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// x0: Input state matrix, s
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// x1: 1 data block output, o
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// x2: 1 data block input, i
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stp x29, x30, [sp, #-16]!
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mov x29, sp
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// x0..3 = s0..3
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ld1 {v0.4s-v3.4s}, [x0]
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ld1 {v8.4s-v11.4s}, [x0]
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bl chacha20_permute
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ld1 {v4.16b-v7.16b}, [x2]
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// o0 = i0 ^ (x0 + s0)
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@ -125,9 +137,28 @@ ENTRY(chacha20_block_xor_neon)
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st1 {v0.16b-v3.16b}, [x1]
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ldp x29, x30, [sp], #16
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ret
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ENDPROC(chacha20_block_xor_neon)
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ENTRY(hchacha20_block_neon)
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// x0: Input state matrix, s
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// x1: output (8 32-bit words)
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stp x29, x30, [sp, #-16]!
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mov x29, sp
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ld1 {v0.4s-v3.4s}, [x0]
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bl chacha20_permute
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st1 {v0.16b}, [x1], #16
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st1 {v3.16b}, [x1]
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ldp x29, x30, [sp], #16
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ret
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ENDPROC(hchacha20_block_neon)
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.align 6
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ENTRY(chacha20_4block_xor_neon)
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// x0: Input state matrix, s
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@ -30,6 +30,7 @@
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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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static void chacha20_doneon(u32 *state, u8 *dst, const u8 *src,
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unsigned int bytes)
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@ -65,20 +66,16 @@ static void chacha20_doneon(u32 *state, u8 *dst, const u8 *src,
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kernel_neon_end();
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}
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static int chacha20_neon(struct skcipher_request *req)
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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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{
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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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struct skcipher_walk walk;
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u32 state[16];
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int err;
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if (!may_use_simd() || req->cryptlen <= CHACHA_BLOCK_SIZE)
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return crypto_chacha_crypt(req);
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err = skcipher_walk_virt(&walk, req, false);
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crypto_chacha_init(state, ctx, walk.iv);
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crypto_chacha_init(state, ctx, iv);
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while (walk.nbytes > 0) {
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unsigned int nbytes = walk.nbytes;
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@ -94,22 +91,73 @@ static int chacha20_neon(struct skcipher_request *req)
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return err;
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}
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static struct skcipher_alg alg = {
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.base.cra_name = "chacha20",
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.base.cra_driver_name = "chacha20-neon",
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.base.cra_priority = 300,
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.base.cra_blocksize = 1,
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.base.cra_ctxsize = sizeof(struct chacha_ctx),
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.base.cra_module = THIS_MODULE,
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static int chacha20_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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.min_keysize = CHACHA_KEY_SIZE,
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.max_keysize = CHACHA_KEY_SIZE,
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.ivsize = CHACHA_IV_SIZE,
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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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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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}
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static int xchacha20_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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struct chacha_ctx subctx;
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u32 state[16];
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u8 real_iv[16];
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if (req->cryptlen <= CHACHA_BLOCK_SIZE || !may_use_simd())
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return crypto_xchacha_crypt(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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kernel_neon_end();
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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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}
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static struct skcipher_alg algs[] = {
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{
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.base.cra_name = "chacha20",
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.base.cra_driver_name = "chacha20-neon",
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.base.cra_priority = 300,
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.base.cra_blocksize = 1,
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.base.cra_ctxsize = sizeof(struct chacha_ctx),
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.base.cra_module = THIS_MODULE,
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.min_keysize = CHACHA_KEY_SIZE,
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.max_keysize = CHACHA_KEY_SIZE,
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.ivsize = CHACHA_IV_SIZE,
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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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}, {
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.base.cra_name = "xchacha20",
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.base.cra_driver_name = "xchacha20-neon",
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.base.cra_priority = 300,
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.base.cra_blocksize = 1,
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.base.cra_ctxsize = sizeof(struct chacha_ctx),
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.base.cra_module = THIS_MODULE,
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.min_keysize = CHACHA_KEY_SIZE,
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.max_keysize = CHACHA_KEY_SIZE,
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.ivsize = XCHACHA_IV_SIZE,
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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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}
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};
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static int __init chacha20_simd_mod_init(void)
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@ -117,12 +165,12 @@ static int __init chacha20_simd_mod_init(void)
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if (!(elf_hwcap & HWCAP_ASIMD))
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return -ENODEV;
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return crypto_register_skcipher(&alg);
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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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{
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crypto_unregister_skcipher(&alg);
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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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@ -131,3 +179,6 @@ module_exit(chacha20_simd_mod_fini);
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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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MODULE_ALIAS_CRYPTO("chacha20-neon");
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MODULE_ALIAS_CRYPTO("xchacha20");
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MODULE_ALIAS_CRYPTO("xchacha20-neon");
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