crypto: riscv - add vector crypto accelerated SM4

Add an implementation of SM4 using the Zvksed 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', and greatly
reducing code duplication.

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/20240122002024.27477-11-ebiggers@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

arch/riscv/crypto/Kconfig

@@ -73,4 +73,21 @@ config CRYPTO_SM3_RISCV64
 	  - Zvksh vector crypto extension
 	  - Zvkb vector crypto extension
 
+config CRYPTO_SM4_RISCV64
+	tristate "Ciphers: SM4 (ShangMi 4)"
+	depends on 64BIT && RISCV_ISA_V && TOOLCHAIN_HAS_VECTOR_CRYPTO
+	select CRYPTO_ALGAPI
+	select CRYPTO_SM4
+	help
+	  SM4 block cipher algorithm (OSCCA GB/T 32907-2016,
+	  ISO/IEC 18033-3:2010/Amd 1:2021)
+
+	  SM4 (GBT.32907-2016) is a cryptographic standard issued by the
+	  Organization of State Commercial Administration of China (OSCCA)
+	  as an authorized cryptographic algorithm for use within China.
+
+	  Architecture: riscv64 using:
+	  - Zvksed vector crypto extension
+	  - Zvkb vector crypto extension
+
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