diff --git a/src/cmd/asm/internal/asm/testdata/s390x.s b/src/cmd/asm/internal/asm/testdata/s390x.s
index 82aa445356..977190678f 100644
--- a/src/cmd/asm/internal/asm/testdata/s390x.s
+++ b/src/cmd/asm/internal/asm/testdata/s390x.s
@@ -419,9 +419,9 @@ 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
-	KMA	R6, R2, R4		// b9296024
-	KMCTR	R6, R2, R4		// b92d6024
+	KDSA	R0, R8                 // b93a0008
+	KMA	R2, R6, R4              // b9296024
+	KMCTR   R2, R6, R4              // b92d6024
 
 	// vector add and sub instructions
 	VAB	V3, V4, V4              // e743400000f3
diff --git a/src/cmd/internal/obj/s390x/asmz.go b/src/cmd/internal/obj/s390x/asmz.go
index bf6d48e305..7b560e0053 100644
--- a/src/cmd/internal/obj/s390x/asmz.go
+++ b/src/cmd/internal/obj/s390x/asmz.go
@@ -4434,7 +4434,7 @@ func (c *ctxtz) asmout(p *obj.Prog, asm *[]byte) {
 		}
 		zRRE(op_KDSA, uint32(p.From.Reg), uint32(p.To.Reg), asm)
 
-	case 126: // KMA and KMCTR - CIPHER MESSAGE WITH AUTHENTICATION; CIPHER MESSAGE WITH
+	case 126: // KMA and KMCTR - CIPHER MESSAGE WITH AUTHENTICATION; CIPHER MESSAGE WITH COUNTER
 		var opcode uint32
 		switch p.As {
 		default:
@@ -4458,16 +4458,13 @@ func (c *ctxtz) asmout(p *obj.Prog, asm *[]byte) {
 			if p.Reg&1 != 0 {
 				c.ctxt.Diag("third argument must be even register in %v", p)
 			}
-			if p.Reg == p.To.Reg || p.Reg == p.From.Reg {
-				c.ctxt.Diag("third argument must not be input or output argument registers in %v", p)
-			}
 			if p.As == AKMA {
 				opcode = op_KMA
 			} else if p.As == AKMCTR {
 				opcode = op_KMCTR
 			}
 		}
-		zRRF(opcode, uint32(p.From.Reg), 0, uint32(p.Reg), uint32(p.To.Reg), asm)
+		zRRF(opcode, uint32(p.Reg), 0, uint32(p.From.Reg), uint32(p.To.Reg), asm)
 	}
 }
 
diff --git a/src/crypto/aes/asm_s390x.s b/src/crypto/aes/asm_s390x.s
index efcce3a0d9..a233714fb8 100644
--- a/src/crypto/aes/asm_s390x.s
+++ b/src/crypto/aes/asm_s390x.s
@@ -127,7 +127,7 @@ crypt:
 	MOVD	src_base+56(FP), R6 // src
 	MOVD	src_len+64(FP), R7  // len
 loop:
-	KMCTR	R6, R2, R4          // cipher message with counter (KMCTR)
+	KMCTR	R4, R2, R6          // cipher message with counter (KMCTR)
 	BVS	loop                // branch back if interrupted
 	RET
 crash:
@@ -180,7 +180,7 @@ TEXT ·kmaGCM(SB),NOSPLIT,$112-120
 	MVC	$8, 24(R8), 104(R1)
 
 kma:
-	KMA	R6, R2, R4	 // Cipher Message with Authentication
+	KMA	R2, R6, R4       // Cipher Message with Authentication
 	BVS	kma
 
 	MOVD	tag+104(FP), R2
diff --git a/src/internal/cpu/cpu_s390x.s b/src/internal/cpu/cpu_s390x.s
index c55a4c725d..4ffbbde38d 100644
--- a/src/internal/cpu/cpu_s390x.s
+++ b/src/internal/cpu/cpu_s390x.s
@@ -30,14 +30,14 @@ TEXT ·kmcQuery(SB), NOSPLIT|NOFRAME, $0-16
 TEXT ·kmctrQuery(SB), NOSPLIT|NOFRAME, $0-16
 	MOVD $0, R0         // set function code to 0 (KMCTR-Query)
 	MOVD $ret+0(FP), R1 // address of 16-byte return value
-	KMCTR R6, R2, R4    // cipher message with counter (KMCTR)
+	KMCTR R2, R4, R4    // cipher message with counter (KMCTR)
 	RET
 
 // func kmaQuery() queryResult
 TEXT ·kmaQuery(SB), NOSPLIT|NOFRAME, $0-16
 	MOVD $0, R0         // set function code to 0 (KMA-Query)
 	MOVD $ret+0(FP), R1 // address of 16-byte return value
-	KMA  R6, R2, R4     // cipher message with authentication (KMA)
+	KMA  R2, R6, R4     // cipher message with authentication (KMA)
 	RET
 
 // func kimdQuery() queryResult