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-rw-r--r--arch/arm/crypto/chacha20-neon-glue.c127
1 files changed, 127 insertions, 0 deletions
diff --git a/arch/arm/crypto/chacha20-neon-glue.c b/arch/arm/crypto/chacha20-neon-glue.c
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index 000000000000..59a7be08e80c
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+++ b/arch/arm/crypto/chacha20-neon-glue.c
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+/*
+ * ChaCha20 256-bit cipher algorithm, RFC7539, ARM NEON functions
+ *
+ * Copyright (C) 2016 Linaro, Ltd. <ard.biesheuvel@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/hwcap.h>
+#include <asm/neon.h>
+#include <asm/simd.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 || !may_use_simd())
+ 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.stride);
+
+ 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_module = THIS_MODULE,
+
+ .min_keysize = CHACHA20_KEY_SIZE,
+ .max_keysize = CHACHA20_KEY_SIZE,
+ .ivsize = CHACHA20_IV_SIZE,
+ .chunksize = CHACHA20_BLOCK_SIZE,
+ .walksize = 4 * CHACHA20_BLOCK_SIZE,
+ .setkey = crypto_chacha20_setkey,
+ .encrypt = chacha20_neon,
+ .decrypt = chacha20_neon,
+};
+
+static int __init chacha20_simd_mod_init(void)
+{
+ if (!(elf_hwcap & HWCAP_NEON))
+ return -ENODEV;
+
+ 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@linaro.org>");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS_CRYPTO("chacha20");