From 4ed467a7d4ed37d41e9da72cc1c11cf3c7213984 Mon Sep 17 00:00:00 2001
From: Emman <emman.sun@cargosmart.com>
Date: Thu, 13 Jan 2022 09:00:08 +0800
Subject: [PATCH] [SM4] fallback again

---
 sm4/gcm_arm64.s      | 33 +++++++--------------------------
 sm4/sm4_gcm_arm64.go |  6 ++++--
 sm4/sm4_gcm_test.go  |  4 ++--
 3 files changed, 13 insertions(+), 30 deletions(-)

diff --git a/sm4/gcm_arm64.s b/sm4/gcm_arm64.s
index 40bef73..c436206 100644
--- a/sm4/gcm_arm64.s
+++ b/sm4/gcm_arm64.s
@@ -153,14 +153,14 @@ TEXT ·gcmSm4Finish(SB),NOSPLIT,$0
 	SM4_TAO_L1(x, y, z, z1, z2);                      \
 	VEOR x.B16, t0.B16, t0.B16
 
-// func gcmSm4Init(productTable *[256]byte, rk []uint32)
-TEXT ·gcmSm4Init(SB),NOSPLIT,$0
+// func precomputeTableAsm(productTable *[256]byte, src *[16]byte)
+TEXT ·precomputeTableAsm(SB),NOSPLIT,$0
 #define pTbl R0
-#define RK R1
+#define SRC R1
 #define I R2
 
 	MOVD productTable+0(FP), pTbl
-	MOVD rk+8(FP), RK
+	MOVD src+8(FP), SRC
 
 	MOVD	$0xC2, I
 	LSL	$56, I
@@ -169,27 +169,8 @@ TEXT ·gcmSm4Init(SB),NOSPLIT,$0
 	VMOV	I, POLY.D[1]
 	VEOR	ZERO.B16, ZERO.B16, ZERO.B16
 
-	// Encrypt block 0 with the SM4 keys to generate the hash key H
-	VEOR	B0.B16, B0.B16, B0.B16
-	VEOR	B1.B16, B1.B16, B1.B16
-	VEOR	B2.B16, B2.B16, B2.B16
-	VEOR	B3.B16, B3.B16, B3.B16
-	EOR R3, R3
-
-sm4InitEncLoop:	
-	SM4_ROUND(0, RK, K0, K1, K2, K3, K4, B0, B1, B2, B3)
-	SM4_ROUND(1, RK, K0, K1, K2, K3, K4, B1, B2, B3, B0)
-	SM4_ROUND(2, RK, K0, K1, K2, K3, K4, B2, B3, B0, B1)
-	SM4_ROUND(3, RK, K0, K1, K2, K3, K4, B3, B0, B1, B2)
-
-	ADD $16, R3
-	CMP $128, R3
-	BNE sm4InitEncLoop
-
-	VMOV B0.S[0], B0.S[2]
-	VMOV B1.S[0], B0.S[3]
-	VMOV B2.S[0], B0.S[0]
-	VMOV B3.S[0], B0.S[1]
+	VLD1 (SRC), [B0.B16]
+	VREV64	B0.B16, B0.B16
 
 	// Multiply by 2 modulo P
 	VMOV	B0.D[0], I
@@ -247,7 +228,7 @@ initLoop:
 	BNE	initLoop
 	RET
 #undef I
-#undef RK
+#undef SRC
 #undef pTbl	
 
 // func gcmSm4Data(productTable *[256]byte, data []byte, T *[16]byte)
diff --git a/sm4/sm4_gcm_arm64.go b/sm4/sm4_gcm_arm64.go
index 9949176..ed4dd8b 100644
--- a/sm4/sm4_gcm_arm64.go
+++ b/sm4/sm4_gcm_arm64.go
@@ -21,7 +21,7 @@ type sm4CipherGCM struct {
 var _ gcmAble = (*sm4CipherGCM)(nil)
 
 //go:noescape
-func gcmSm4Init(productTable *[256]byte, rk []uint32)
+func precomputeTableAsm(productTable *[256]byte, src *[16]byte)
 
 //go:noescape
 func gcmSm4Data(productTable *[256]byte, data []byte, T *[16]byte)
@@ -41,7 +41,9 @@ func (c *sm4CipherGCM) NewGCM(nonceSize, tagSize int) (cipher.AEAD, error) {
 	g.cipher = &c.sm4CipherAsm
 	g.nonceSize = nonceSize
 	g.tagSize = tagSize
-	gcmSm4Init(&g.bytesProductTable, g.cipher.enc)
+	var key [gcmBlockSize]byte
+	c.Encrypt(key[:], key[:])
+	precomputeTableAsm(&g.bytesProductTable, &key)
 	return g, nil
 }
 
diff --git a/sm4/sm4_gcm_test.go b/sm4/sm4_gcm_test.go
index 75acca9..4b7c7f1 100644
--- a/sm4/sm4_gcm_test.go
+++ b/sm4/sm4_gcm_test.go
@@ -1,5 +1,5 @@
-//go:build amd64 || arm64
-// +build amd64 arm64
+//go:build amd64
+// +build amd64
 
 package sm4