crypto: x86/sm2 - add Zhaoxin SM2 algorithm implementation

Add support for SM2 (ShangMi 2) public key algorithm by Zhaoxin GMI
Instruction. The purpose of this driver is to ensure that the application
has both high performance and high security.

Signed-off-by: leoliu-oc <leoliu-oc@zhaoxin.com>

arch/x86/crypto/Kconfig

@@ -553,4 +553,16 @@ config CRYPTO_CRCT10DIF_PCLMUL
 	  Architecture: x86_64 using:
 	  - PCLMULQDQ (carry-less multiplication)
 
+config CRYPTO_SM2_ZHAOXIN_GMI
+	tristate "SM2 Cipher algorithm (Zhaoxin GMI Instruction)"
+	depends on X86 && (CPU_SUP_CENTAUR || CPU_SUP_ZHAOXIN)
+	default m
+	select CRYPTO_AKCIPHER
+	select CRYPTO_MANAGER
+	help
+	  SM2 (ShangMi 2) public key algorithm by Zhaoxin GMI Instruction
+
+	  Published by State Encryption Management Bureau, China,
+	  as specified by OSCCA GM/T 0003.1-2012 -- 0003.5-2012.
+
 endmenu

arch/x86/crypto/Makefile

@@ -109,6 +109,7 @@ aria-aesni-avx2-x86_64-y := aria-aesni-avx2-asm_64.o aria_aesni_avx2_glue.o
 obj-$(CONFIG_CRYPTO_ARIA_GFNI_AVX512_X86_64) += aria-gfni-avx512-x86_64.o
 aria-gfni-avx512-x86_64-y := aria-gfni-avx512-asm_64.o aria_gfni_avx512_glue.o
 
+obj-$(CONFIG_CRYPTO_SM2_ZHAOXIN_GMI) += sm2-zhaoxin-gmi.o
 obj-$(CONFIG_CRYPTO_SM3_ZHAOXIN_GMI) += sm3-zhaoxin-gmi.o
 obj-$(CONFIG_CRYPTO_SM4_ZHAOXIN_GMI) += sm4-zhaoxin-gmi.o
 

arch/x86/crypto/sm2-zhaoxin-gmi.c

@@ -0,0 +1,158 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * SM2 asymmetric public-key algorithm
+ * as specified by OSCCA GM/T 0003.1-2012 -- 0003.5-2012 SM2 and
+ * described at https://tools.ietf.org/html/draft-shen-sm2-ecdsa-02
+ *
+ * Copyright (c) 2023 Shanghai Zhaoxin Semiconductor LTD.
+ * Authors: YunShen <yunshen@zhaoxin.com>
+ */
+
+#include <linux/module.h>
+#include <linux/mpi.h>
+#include <crypto/internal/akcipher.h>
+#include <crypto/akcipher.h>
+#include <crypto/sm2.h>
+#include <asm/cpufeature.h>
+#include <asm/processor.h>
+#include <asm/cpu_device_id.h>
+
+#define SCRATCH_SIZE (4 * 2048)
+
+#define SM2_CWORD_VERIFY 0x8
+#define SM2_VERIFY_PASS 1
+
+struct sm2_cipher_data {
+	u8 pub_key[65]; /* public key */
+};
+
+/* Load supported features of the CPU to see if the SM2 is available. */
+static int zhaoxin_gmi_available(void)
+{
+	if (!boot_cpu_has(X86_FEATURE_SM2_EN)) {
+		pr_err("can't enable hardware SM2 if Zhaoxin GMI SM2 is not enabled\n");
+		return -ENODEV;
+	}
+	return 0;
+}
+
+/* Zhaoxin sm2 verify function */
+static inline size_t zhaoxin_gmi_sm2_verify(unsigned char *key, unsigned char *hash,
+				unsigned char *sig, unsigned char *scratch)
+{
+	size_t result;
+
+	asm volatile(
+		".byte 0xf2, 0x0f, 0xa6, 0xc0"
+		: "=c"(result)
+		: "a"(hash), "b"(key), "d"(SM2_CWORD_VERIFY), "S"(scratch), "D"(sig)
+		: "memory");
+
+	return result;
+}
+
+/* Zhaoxin sm2 verify function */
+static int _zhaoxin_sm2_verify(struct sm2_cipher_data *ec, unsigned char *hash, unsigned char *sig)
+{
+	unsigned char *scratch = kzalloc(SCRATCH_SIZE, GFP_KERNEL);
+	int ret = -EKEYREJECTED;
+	size_t result;
+
+	result = zhaoxin_gmi_sm2_verify(ec->pub_key, hash, sig, scratch);
+	if (result == SM2_VERIFY_PASS)
+		ret = 0;
+
+	kfree(scratch);
+
+	return ret;
+}
+
+static int zhaoxin_sm2_verify(struct akcipher_request *req)
+{
+	struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
+	struct sm2_cipher_data *ec = akcipher_tfm_ctx(tfm);
+	unsigned char *buffer;
+	int ret, buf_len;
+
+	buf_len = req->src_len + req->dst_len;
+	buffer = kmalloc(buf_len, GFP_KERNEL);
+	if (!buffer)
+		return -ENOMEM;
+
+	sg_pcopy_to_buffer(req->src, sg_nents_for_len(req->src, buf_len), buffer, buf_len, 0);
+	ret = _zhaoxin_sm2_verify(ec, buffer + req->src_len, buffer);
+
+	kfree(buffer);
+
+	return ret;
+}
+
+static int zhaoxin_sm2_set_pub_key(struct crypto_akcipher *tfm, const void *key,
+				unsigned int keylen)
+{
+	struct sm2_cipher_data *ec = akcipher_tfm_ctx(tfm);
+
+	memcpy(ec->pub_key, key, keylen);
+
+	return 0;
+}
+
+static unsigned int zhaoxin_sm2_max_size(struct crypto_akcipher *tfm)
+{
+	/* Unlimited max size */
+	return PAGE_SIZE;
+}
+
+static int zhaoxin_sm2_init_tfm(struct crypto_akcipher *tfm)
+{
+	return zhaoxin_gmi_available();
+}
+
+static void zhaoxin_sm2_exit_tfm(struct crypto_akcipher *tfm)
+{
+	struct sm2_cipher_data *ec = akcipher_tfm_ctx(tfm);
+
+	memset(ec, 0, sizeof(*ec));
+}
+
+static struct akcipher_alg zhaoxin_sm2 = {
+	.verify = zhaoxin_sm2_verify,
+	.set_pub_key = zhaoxin_sm2_set_pub_key,
+	.max_size = zhaoxin_sm2_max_size,
+	.init = zhaoxin_sm2_init_tfm,
+	.exit = zhaoxin_sm2_exit_tfm,
+	.base = {
+		.cra_name = "sm2",
+		.cra_driver_name = "zhaoxin-gmi-sm2",
+		.cra_priority = 150,
+		.cra_module = THIS_MODULE,
+		.cra_ctxsize = sizeof(struct sm2_cipher_data),
+	},
+};
+
+static const struct x86_cpu_id zhaoxin_sm2_cpu_ids[] = {
+	X86_MATCH_FEATURE(X86_FEATURE_SM2, NULL),
+	{}
+};
+MODULE_DEVICE_TABLE(x86cpu, zhaoxin_sm2_cpu_ids);
+
+static int __init zhaoxin_sm2_init(void)
+{
+	if (!x86_match_cpu(zhaoxin_sm2_cpu_ids))
+		return -ENODEV;
+
+	return crypto_register_akcipher(&zhaoxin_sm2);
+}
+
+static void __exit zhaoxin_sm2_exit(void)
+{
+	crypto_unregister_akcipher(&zhaoxin_sm2);
+}
+
+module_init(zhaoxin_sm2_init);
+module_exit(zhaoxin_sm2_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("YunShen <yunshen@zhaoxin.com>");
+MODULE_DESCRIPTION("SM2 Zhaoxin GMI Algorithm");
+MODULE_ALIAS_CRYPTO("zhaoxin-gmi-sm2");

arch/x86/include/asm/cpufeatures.h

@@ -146,6 +146,8 @@
 #define X86_FEATURE_HYPERVISOR		( 4*32+31) /* Running on a hypervisor */
 
 /* VIA/Cyrix/Centaur-defined CPU features, CPUID level 0xC0000001, word 5 */
+#define X86_FEATURE_SM2			(5*32 + 0) /* SM2 Zhaoxin GMI present */
+#define X86_FEATURE_SM2_EN		(5*32 + 1) /* SM2 Zhaoxin GMI enabled */
 #define X86_FEATURE_XSTORE		( 5*32+ 2) /* "rng" RNG present (xstore) */
 #define X86_FEATURE_XSTORE_EN		( 5*32+ 3) /* "rng_en" RNG enabled */
 #define X86_FEATURE_CCS        (5*32+4) /*  "sm3 sm4" present */