Zvk: Implement Zvksed, vector SM4 Block Cipher

Implement the Zvksed sub-extension, "ShangMi Suite: SM4 Block Cipher":
 - vsm4k.vi, vector SM4 key expansion,
 - vsm4r.{vs,vv}, vector SM4 rounds.

This also introduces a header for common vector SM4 logic.

Co-authored-by: Raghav Gupta <rgupta@rivosinc.com>
Co-authored-by: Albert Jakieła <aja@semihalf.com>
Signed-off-by: Eric Gouriou <ego@rivosinc.com>

1 files changed, 60 insertions, 0 deletions

diff --git a/riscv/zvksed_ext_macros.h b/riscv/zvksed_ext_macros.h
new file mode 100644
index 0000000..46e399b
--- /dev/null
+++ b/riscv/zvksed_ext_macros.h
@@ -0,0 +1,60 @@
+// Helper macros and functions to help implement instructions defined as part of
+// the RISC-V Zvksed extension (vectorized SM4).
+
+#include "insns/sm4_common.h"
+#include "zvk_ext_macros.h"
+
+#ifndef RISCV_ZVKSED_MACROS_H_
+#define RISCV_ZVKSED_MACROS_H_
+
+// Constraints common to all vsm4* instructions:
+//  - Zvksed is enabled
+//  - VSEW == 32
+//  - EGW (128) <= LMUL * VLEN
+//
+// The constraint that vstart and vl are both EGS (4) aligned
+// is checked in the VI_ZVK_..._EGU32x4_..._LOOP macros.
+#define require_vsm4_constraints \
+  do { \
+    require_zvksed; \
+    require(P.VU.vsew == 32); \
+    require_egw_fits(128); \
+  } while (false)
+
+// Returns a uint32_t value constructed from the 4 bytes (uint8_t)
+// provided in "Little Endian" (LE) order, i.e., from least significant (B0)
+// to most significant (B3).
+#define ZVKSED_U32_FROM_U8_LE(B0, B1, B2, B3) \
+  (((uint32_t)(B0)) <<  0 | \
+   ((uint32_t)(B1)) <<  8 | \
+   ((uint32_t)(B2)) << 16 | \
+   ((uint32_t)(B3)) << 24)
+
+// Get byte BYTE of the SBox.
+#define ZVKSED_SBOX(BYTE)  (sm4_sbox[(BYTE)])
+
+// Given an unsigned integer value 'X' and a byte index,
+// returns a uint8_t value for the byte at the given index.
+#define ZVKSED_EXTRACT_U8(X, BYTE_IDX) ((uint8_t)((X) >> (BYTE_IDX * 8)))
+
+// Apply the nonlinear transformation tau to a 32 bit word B - section 6.2.1.
+// of the IETF draft.
+#define ZVKSED_SUB_BYTES(B) \
+  ZVKSED_U32_FROM_U8_LE(ZVKSED_SBOX(ZVKSED_EXTRACT_U8((B), 0)), \
+                        ZVKSED_SBOX(ZVKSED_EXTRACT_U8((B), 1)), \
+                        ZVKSED_SBOX(ZVKSED_EXTRACT_U8((B), 2)), \
+                        ZVKSED_SBOX(ZVKSED_EXTRACT_U8((B), 3)))
+
+// Perform the linear transformation L to a 32 bit word S and xor it with a 32
+// bit word X - section 6.2.2. of the IETF draft.
+#define ZVKSED_ROUND(X, S) \
+  ((X) ^ \
+   ((S) ^ ZVK_ROL32((S), 2) ^ ZVK_ROL32((S), 10) ^ \
+    ZVK_ROL32((S), 18) ^ ZVK_ROL32((S), 24)))
+
+// Perform the linear transformation L' to a 32 bit word S and xor it with a 32
+// bit word X - section 6.2.2. of the IETF draft.
+#define ZVKSED_ROUND_KEY(X, S) \
+  ((X) ^ ((S) ^ ZVK_ROL32((S), 13) ^ ZVK_ROL32((S), 23)))
+
+#endif // RISCV_ZVKSED_MACROS_H_