From 61719e18f7715e4fbd0914395633b15a4a2e17a7 Mon Sep 17 00:00:00 2001
From: Srinivas Pokala <Pokala.Srinivas@ibm.com>
Date: Wed, 14 Jun 2023 07:13:37 +0200
Subject: [PATCH] cmd/asm: add KDSA instruction support

KDSA(Compute Digital Signature Authentication) instruction provides
support for the signing and verification of elliptic curves

Change-Id: I19996a307162dd4f476a1cfe4f8d1a74a609e6c1
Reviewed-on: https://go-review.googlesource.com/c/go/+/503215
Reviewed-by: Cherry Mui <cherryyz@google.com>
Reviewed-by: David Chase <drchase@google.com>
Run-TryBot: Cherry Mui <cherryyz@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
---
 src/cmd/asm/internal/asm/testdata/s390x.s |  1 +
 src/cmd/internal/obj/s390x/a.out.go       |  1 +
 src/cmd/internal/obj/s390x/anames.go      |  1 +
 src/cmd/internal/obj/s390x/asmz.go        | 17 +++++++++++++++++
 src/crypto/ecdsa/ecdsa_s390x.s            |  2 +-
 src/internal/cpu/cpu_s390x.s              |  2 +-
 6 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/src/cmd/asm/internal/asm/testdata/s390x.s b/src/cmd/asm/internal/asm/testdata/s390x.s
index c73aecdaa6..bb1573ae5b 100644
--- a/src/cmd/asm/internal/asm/testdata/s390x.s
+++ b/src/cmd/asm/internal/asm/testdata/s390x.s
@@ -419,6 +419,7 @@ TEXT main·foo(SB),DUPOK|NOSPLIT,$16-0 // TEXT main.foo(SB), DUPOK|NOSPLIT, $16-
 	KMC	R2, R6                 // b92f0026
 	KLMD	R2, R8                 // b93f0028
 	KIMD	R0, R4                 // b93e0004
+	KDSA    R0, R8                 // b93a0008
 
 	// vector add and sub instructions
 	VAB	V3, V4, V4              // e743400000f3
diff --git a/src/cmd/internal/obj/s390x/a.out.go b/src/cmd/internal/obj/s390x/a.out.go
index 0b1aa5af16..ef02fed283 100644
--- a/src/cmd/internal/obj/s390x/a.out.go
+++ b/src/cmd/internal/obj/s390x/a.out.go
@@ -485,6 +485,7 @@ const (
 	AKMC
 	AKLMD
 	AKIMD
+	AKDSA
 
 	// vector
 	AVA
diff --git a/src/cmd/internal/obj/s390x/anames.go b/src/cmd/internal/obj/s390x/anames.go
index d5f5f343e3..40cc5e6b0d 100644
--- a/src/cmd/internal/obj/s390x/anames.go
+++ b/src/cmd/internal/obj/s390x/anames.go
@@ -211,6 +211,7 @@ var Anames = []string{
 	"KMC",
 	"KLMD",
 	"KIMD",
+	"KDSA",
 	"VA",
 	"VAB",
 	"VAH",
diff --git a/src/cmd/internal/obj/s390x/asmz.go b/src/cmd/internal/obj/s390x/asmz.go
index 81e7a2d62e..a744d742cf 100644
--- a/src/cmd/internal/obj/s390x/asmz.go
+++ b/src/cmd/internal/obj/s390x/asmz.go
@@ -344,6 +344,9 @@ var optab = []Optab{
 	// KM
 	{i: 124, as: AKM, a1: C_REG, a6: C_REG},
 
+	// KDSA
+	{i: 125, as: AKDSA, a1: C_REG, a6: C_REG},
+
 	// vector instructions
 
 	// VRX store
@@ -2638,6 +2641,10 @@ const (
 	op_VUPLL  uint32 = 0xE7D4 // 	VRR-a	VECTOR UNPACK LOGICAL LOW
 	op_VUPL   uint32 = 0xE7D6 // 	VRR-a	VECTOR UNPACK LOW
 	op_VMSL   uint32 = 0xE7B8 // 	VRR-d	VECTOR MULTIPLY SUM LOGICAL
+
+	// added in z15
+	op_KDSA uint32 = 0xB93A // FORMAT_RRE        COMPUTE DIGITAL SIGNATURE AUTHENTICATION (KDSA)
+
 )
 
 func oclass(a *obj.Addr) int {
@@ -4411,6 +4418,16 @@ func (c *ctxtz) asmout(p *obj.Prog, asm *[]byte) {
 			opcode = op_KIMD
 		}
 		zRRE(opcode, uint32(p.From.Reg), uint32(p.To.Reg), asm)
+
+	case 125: // KDSA sign and verify
+		if p.To.Reg == REG_R0 {
+			c.ctxt.Diag("second argument must not be R0 in %v", p)
+		}
+		if p.To.Reg&1 != 0 {
+			c.ctxt.Diag("second argument must be an even register in %v", p)
+		}
+		zRRE(op_KDSA, uint32(p.From.Reg), uint32(p.To.Reg), asm)
+
 	}
 }
 
diff --git a/src/crypto/ecdsa/ecdsa_s390x.s b/src/crypto/ecdsa/ecdsa_s390x.s
index ba5b3bf9fa..ea1f4469e9 100644
--- a/src/crypto/ecdsa/ecdsa_s390x.s
+++ b/src/crypto/ecdsa/ecdsa_s390x.s
@@ -10,7 +10,7 @@ TEXT ·kdsa(SB), NOSPLIT|NOFRAME, $0-24
 	MOVD params+8(FP), R1 // address parameter block
 
 loop:
-	WORD $0xB93A0008 // compute digital signature authentication
+	KDSA R0, R4      // compute digital signature authentication
 	BVS  loop        // branch back if interrupted
 	BGT  retry       // signing unsuccessful, but retry with new CSPRN
 	BLT  error       // condition code of 1 indicates a failure
diff --git a/src/internal/cpu/cpu_s390x.s b/src/internal/cpu/cpu_s390x.s
index 9f73113870..46b3b53481 100644
--- a/src/internal/cpu/cpu_s390x.s
+++ b/src/internal/cpu/cpu_s390x.s
@@ -58,6 +58,6 @@ TEXT ·klmdQuery(SB), NOSPLIT|NOFRAME, $0-16
 TEXT ·kdsaQuery(SB), NOSPLIT|NOFRAME, $0-16
 	MOVD $0, R0         // set function code to 0 (KLMD-Query)
 	MOVD $ret+0(FP), R1 // address of 16-byte return value
-	WORD $0xB93A0008    // compute digital signature authentication
+	KDSA R0, R4      // compute digital signature authentication
 	RET
 
-- 
2.50.0