v4.19.13 snapshot.
diff --git a/crypto/chacha20_generic.c b/crypto/chacha20_generic.c
new file mode 100644
index 0000000..e451c3c
--- /dev/null
+++ b/crypto/chacha20_generic.c
@@ -0,0 +1,136 @@
+/*
+ * ChaCha20 256-bit cipher algorithm, RFC7539
+ *
+ * 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 <asm/unaligned.h>
+#include <crypto/algapi.h>
+#include <crypto/chacha20.h>
+#include <crypto/internal/skcipher.h>
+#include <linux/module.h>
+
+static void chacha20_docrypt(u32 *state, u8 *dst, const u8 *src,
+ unsigned int bytes)
+{
+ u32 stream[CHACHA20_BLOCK_WORDS];
+
+ if (dst != src)
+ memcpy(dst, src, bytes);
+
+ while (bytes >= CHACHA20_BLOCK_SIZE) {
+ chacha20_block(state, stream);
+ crypto_xor(dst, (const u8 *)stream, CHACHA20_BLOCK_SIZE);
+ bytes -= CHACHA20_BLOCK_SIZE;
+ dst += CHACHA20_BLOCK_SIZE;
+ }
+ if (bytes) {
+ chacha20_block(state, stream);
+ crypto_xor(dst, (const u8 *)stream, bytes);
+ }
+}
+
+void crypto_chacha20_init(u32 *state, struct chacha20_ctx *ctx, u8 *iv)
+{
+ state[0] = 0x61707865; /* "expa" */
+ state[1] = 0x3320646e; /* "nd 3" */
+ state[2] = 0x79622d32; /* "2-by" */
+ state[3] = 0x6b206574; /* "te k" */
+ state[4] = ctx->key[0];
+ state[5] = ctx->key[1];
+ state[6] = ctx->key[2];
+ state[7] = ctx->key[3];
+ state[8] = ctx->key[4];
+ state[9] = ctx->key[5];
+ state[10] = ctx->key[6];
+ state[11] = ctx->key[7];
+ state[12] = get_unaligned_le32(iv + 0);
+ state[13] = get_unaligned_le32(iv + 4);
+ state[14] = get_unaligned_le32(iv + 8);
+ state[15] = get_unaligned_le32(iv + 12);
+}
+EXPORT_SYMBOL_GPL(crypto_chacha20_init);
+
+int crypto_chacha20_setkey(struct crypto_skcipher *tfm, const u8 *key,
+ unsigned int keysize)
+{
+ struct chacha20_ctx *ctx = crypto_skcipher_ctx(tfm);
+ int i;
+
+ if (keysize != CHACHA20_KEY_SIZE)
+ return -EINVAL;
+
+ for (i = 0; i < ARRAY_SIZE(ctx->key); i++)
+ ctx->key[i] = get_unaligned_le32(key + i * sizeof(u32));
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(crypto_chacha20_setkey);
+
+int crypto_chacha20_crypt(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;
+
+ err = skcipher_walk_virt(&walk, req, true);
+
+ crypto_chacha20_init(state, ctx, walk.iv);
+
+ while (walk.nbytes > 0) {
+ unsigned int nbytes = walk.nbytes;
+
+ if (nbytes < walk.total)
+ nbytes = round_down(nbytes, walk.stride);
+
+ chacha20_docrypt(state, walk.dst.virt.addr, walk.src.virt.addr,
+ nbytes);
+ err = skcipher_walk_done(&walk, walk.nbytes - nbytes);
+ }
+
+ return err;
+}
+EXPORT_SYMBOL_GPL(crypto_chacha20_crypt);
+
+static struct skcipher_alg alg = {
+ .base.cra_name = "chacha20",
+ .base.cra_driver_name = "chacha20-generic",
+ .base.cra_priority = 100,
+ .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,
+ .setkey = crypto_chacha20_setkey,
+ .encrypt = crypto_chacha20_crypt,
+ .decrypt = crypto_chacha20_crypt,
+};
+
+static int __init chacha20_generic_mod_init(void)
+{
+ return crypto_register_skcipher(&alg);
+}
+
+static void __exit chacha20_generic_mod_fini(void)
+{
+ crypto_unregister_skcipher(&alg);
+}
+
+module_init(chacha20_generic_mod_init);
+module_exit(chacha20_generic_mod_fini);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Martin Willi <martin@strongswan.org>");
+MODULE_DESCRIPTION("chacha20 cipher algorithm");
+MODULE_ALIAS_CRYPTO("chacha20");
+MODULE_ALIAS_CRYPTO("chacha20-generic");