crypto: riscv - add vector crypto accelerated GHASH

Add an implementation of GHASH using the zvkg extension.  The assembly
code is derived from OpenSSL code (openssl/openssl#21923) that was
dual-licensed so that it could be reused in the kernel.  Nevertheless,
the assembly has been significantly reworked for integration with the
kernel, for example by using a regular .S file instead of the so-called
perlasm, using the assembler instead of bare '.inst', reducing code
duplication, and eliminating unnecessary endianness conversions.

Co-developed-by: Christoph Müllner <christoph.muellner@vrull.eu>
Signed-off-by: Christoph Müllner <christoph.muellner@vrull.eu>
Co-developed-by: Heiko Stuebner <heiko.stuebner@vrull.eu>
Signed-off-by: Heiko Stuebner <heiko.stuebner@vrull.eu>
Signed-off-by: Jerry Shih <jerry.shih@sifive.com>
Co-developed-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20240122002024.27477-7-ebiggers@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

1 files changed, 168 insertions, 0 deletions

diff --git a/arch/riscv/crypto/ghash-riscv64-glue.c b/arch/riscv/crypto/ghash-riscv64-glue.c
new file mode 100644
index 000000000000..312e7891fd0a
--- /dev/null
+++ b/arch/riscv/crypto/ghash-riscv64-glue.c
@@ -0,0 +1,168 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * GHASH using the RISC-V vector crypto extensions
+ *
+ * Copyright (C) 2023 VRULL GmbH
+ * Author: Heiko Stuebner <heiko.stuebner@vrull.eu>
+ *
+ * Copyright (C) 2023 SiFive, Inc.
+ * Author: Jerry Shih <jerry.shih@sifive.com>
+ */
+
+#include <asm/simd.h>
+#include <asm/vector.h>
+#include <crypto/ghash.h>
+#include <crypto/internal/hash.h>
+#include <crypto/internal/simd.h>
+#include <linux/linkage.h>
+#include <linux/module.h>
+
+asmlinkage void ghash_zvkg(be128 *accumulator, const be128 *key, const u8 *data,
+			   size_t len);
+
+struct riscv64_ghash_tfm_ctx {
+	be128 key;
+};
+
+struct riscv64_ghash_desc_ctx {
+	be128 accumulator;
+	u8 buffer[GHASH_BLOCK_SIZE];
+	u32 bytes;
+};
+
+static int riscv64_ghash_setkey(struct crypto_shash *tfm, const u8 *key,
+				unsigned int keylen)
+{
+	struct riscv64_ghash_tfm_ctx *tctx = crypto_shash_ctx(tfm);
+
+	if (keylen != GHASH_BLOCK_SIZE)
+		return -EINVAL;
+
+	memcpy(&tctx->key, key, GHASH_BLOCK_SIZE);
+
+	return 0;
+}
+
+static int riscv64_ghash_init(struct shash_desc *desc)
+{
+	struct riscv64_ghash_desc_ctx *dctx = shash_desc_ctx(desc);
+
+	*dctx = (struct riscv64_ghash_desc_ctx){};
+
+	return 0;
+}
+
+static inline void
+riscv64_ghash_blocks(const struct riscv64_ghash_tfm_ctx *tctx,
+		     struct riscv64_ghash_desc_ctx *dctx,
+		     const u8 *src, size_t srclen)
+{
+	/* The srclen is nonzero and a multiple of 16. */
+	if (crypto_simd_usable()) {
+		kernel_vector_begin();
+		ghash_zvkg(&dctx->accumulator, &tctx->key, src, srclen);
+		kernel_vector_end();
+	} else {
+		do {
+			crypto_xor((u8 *)&dctx->accumulator, src,
+				   GHASH_BLOCK_SIZE);
+			gf128mul_lle(&dctx->accumulator, &tctx->key);
+			src += GHASH_BLOCK_SIZE;
+			srclen -= GHASH_BLOCK_SIZE;
+		} while (srclen);
+	}
+}
+
+static int riscv64_ghash_update(struct shash_desc *desc, const u8 *src,
+				unsigned int srclen)
+{
+	const struct riscv64_ghash_tfm_ctx *tctx = crypto_shash_ctx(desc->tfm);
+	struct riscv64_ghash_desc_ctx *dctx = shash_desc_ctx(desc);
+	unsigned int len;
+
+	if (dctx->bytes) {
+		if (dctx->bytes + srclen < GHASH_BLOCK_SIZE) {
+			memcpy(dctx->buffer + dctx->bytes, src, srclen);
+			dctx->bytes += srclen;
+			return 0;
+		}
+		memcpy(dctx->buffer + dctx->bytes, src,
+		       GHASH_BLOCK_SIZE - dctx->bytes);
+		riscv64_ghash_blocks(tctx, dctx, dctx->buffer,
+				     GHASH_BLOCK_SIZE);
+		src += GHASH_BLOCK_SIZE - dctx->bytes;
+		srclen -= GHASH_BLOCK_SIZE - dctx->bytes;
+		dctx->bytes = 0;
+	}
+
+	len = round_down(srclen, GHASH_BLOCK_SIZE);
+	if (len) {
+		riscv64_ghash_blocks(tctx, dctx, src, len);
+		src += len;
+		srclen -= len;
+	}
+
+	if (srclen) {
+		memcpy(dctx->buffer, src, srclen);
+		dctx->bytes = srclen;
+	}
+
+	return 0;
+}
+
+static int riscv64_ghash_final(struct shash_desc *desc, u8 *out)
+{
+	const struct riscv64_ghash_tfm_ctx *tctx = crypto_shash_ctx(desc->tfm);
+	struct riscv64_ghash_desc_ctx *dctx = shash_desc_ctx(desc);
+	int i;
+
+	if (dctx->bytes) {
+		for (i = dctx->bytes; i < GHASH_BLOCK_SIZE; i++)
+			dctx->buffer[i] = 0;
+
+		riscv64_ghash_blocks(tctx, dctx, dctx->buffer,
+				     GHASH_BLOCK_SIZE);
+	}
+
+	memcpy(out, &dctx->accumulator, GHASH_DIGEST_SIZE);
+	return 0;
+}
+
+static struct shash_alg riscv64_ghash_alg = {
+	.init = riscv64_ghash_init,
+	.update = riscv64_ghash_update,
+	.final = riscv64_ghash_final,
+	.setkey = riscv64_ghash_setkey,
+	.descsize = sizeof(struct riscv64_ghash_desc_ctx),
+	.digestsize = GHASH_DIGEST_SIZE,
+	.base = {
+		.cra_blocksize = GHASH_BLOCK_SIZE,
+		.cra_ctxsize = sizeof(struct riscv64_ghash_tfm_ctx),
+		.cra_priority = 300,
+		.cra_name = "ghash",
+		.cra_driver_name = "ghash-riscv64-zvkg",
+		.cra_module = THIS_MODULE,
+	},
+};
+
+static int __init riscv64_ghash_mod_init(void)
+{
+	if (riscv_isa_extension_available(NULL, ZVKG) &&
+	    riscv_vector_vlen() >= 128)
+		return crypto_register_shash(&riscv64_ghash_alg);
+
+	return -ENODEV;
+}
+
+static void __exit riscv64_ghash_mod_exit(void)
+{
+	crypto_unregister_shash(&riscv64_ghash_alg);
+}
+
+module_init(riscv64_ghash_mod_init);
+module_exit(riscv64_ghash_mod_exit);
+
+MODULE_DESCRIPTION("GHASH (RISC-V accelerated)");
+MODULE_AUTHOR("Heiko Stuebner <heiko.stuebner@vrull.eu>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_CRYPTO("ghash");