crypto: arm64 - add support for SM4 encryption using special instructions

Add support for the SM4 symmetric cipher implemented using the special
SM4 instructions introduced in ARM architecture revision 8.2.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 73 insertions, 0 deletions

diff --git a/arch/arm64/crypto/sm4-ce-glue.c b/arch/arm64/crypto/sm4-ce-glue.c
new file mode 100644
index 000000000000..b7fb5274b250
--- /dev/null
+++ b/arch/arm64/crypto/sm4-ce-glue.c
@@ -0,0 +1,73 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <asm/neon.h>
+#include <asm/simd.h>
+#include <crypto/sm4.h>
+#include <linux/module.h>
+#include <linux/cpufeature.h>
+#include <linux/crypto.h>
+#include <linux/types.h>
+
+MODULE_ALIAS_CRYPTO("sm4");
+MODULE_ALIAS_CRYPTO("sm4-ce");
+MODULE_DESCRIPTION("SM4 symmetric cipher using ARMv8 Crypto Extensions");
+MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
+MODULE_LICENSE("GPL v2");
+
+asmlinkage void sm4_ce_do_crypt(const u32 *rk, void *out, const void *in);
+
+static void sm4_ce_encrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
+{
+	const struct crypto_sm4_ctx *ctx = crypto_tfm_ctx(tfm);
+
+	if (!may_use_simd()) {
+		crypto_sm4_encrypt(tfm, out, in);
+	} else {
+		kernel_neon_begin();
+		sm4_ce_do_crypt(ctx->rkey_enc, out, in);
+		kernel_neon_end();
+	}
+}
+
+static void sm4_ce_decrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
+{
+	const struct crypto_sm4_ctx *ctx = crypto_tfm_ctx(tfm);
+
+	if (!may_use_simd()) {
+		crypto_sm4_decrypt(tfm, out, in);
+	} else {
+		kernel_neon_begin();
+		sm4_ce_do_crypt(ctx->rkey_dec, out, in);
+		kernel_neon_end();
+	}
+}
+
+static struct crypto_alg sm4_ce_alg = {
+	.cra_name			= "sm4",
+	.cra_driver_name		= "sm4-ce",
+	.cra_priority			= 200,
+	.cra_flags			= CRYPTO_ALG_TYPE_CIPHER,
+	.cra_blocksize			= SM4_BLOCK_SIZE,
+	.cra_ctxsize			= sizeof(struct crypto_sm4_ctx),
+	.cra_module			= THIS_MODULE,
+	.cra_u.cipher = {
+		.cia_min_keysize	= SM4_KEY_SIZE,
+		.cia_max_keysize	= SM4_KEY_SIZE,
+		.cia_setkey		= crypto_sm4_set_key,
+		.cia_encrypt		= sm4_ce_encrypt,
+		.cia_decrypt		= sm4_ce_decrypt
+	}
+};
+
+static int __init sm4_ce_mod_init(void)
+{
+	return crypto_register_alg(&sm4_ce_alg);
+}
+
+static void __exit sm4_ce_mod_fini(void)
+{
+	crypto_unregister_alg(&sm4_ce_alg);
+}
+
+module_cpu_feature_match(SM3, sm4_ce_mod_init);
+module_exit(sm4_ce_mod_fini);