From 58a48a3e3bed76803bb3ac59d1d239dde654f336 Mon Sep 17 00:00:00 2001
From: Srinivas Pokala <Pokala.Srinivas@ibm.com>
Date: Tue, 11 Nov 2025 05:19:47 +0100
Subject: [PATCH] internal/runtime/syscall: Syscall changes for s390x regabi

Updates #40724

Change-Id: I07a01ac1bda71214f01f4a72e15ab469ef275725
Reviewed-on: https://go-review.googlesource.com/c/go/+/719423
Reviewed-by: Vishwanatha HD <vishwanatha.hd@ibm.com>
Reviewed-by: Keith Randall <khr@google.com>
Reviewed-by: David Chase <drchase@google.com>
Reviewed-by: Keith Randall <khr@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
---
 .../runtime/syscall/linux/asm_linux_s390x.s   | 22 ++++++++++++++++++-
 1 file changed, 21 insertions(+), 1 deletion(-)

diff --git a/src/internal/runtime/syscall/linux/asm_linux_s390x.s b/src/internal/runtime/syscall/linux/asm_linux_s390x.s
index 1b27f29390..c912afab64 100644
--- a/src/internal/runtime/syscall/linux/asm_linux_s390x.s
+++ b/src/internal/runtime/syscall/linux/asm_linux_s390x.s
@@ -5,7 +5,16 @@
 #include "textflag.h"
 
 // func Syscall6(num, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2, errno uintptr)
-TEXT ·Syscall6(SB),NOSPLIT,$0-80
+TEXT ·Syscall6<ABIInternal>(SB),NOSPLIT,$0-80
+#ifdef GOEXPERIMENT_regabiargs
+	MOVD	R2, R1
+	MOVD	R3, R2
+	MOVD	R4, R3
+	MOVD	R5, R4
+	MOVD	R6, R5
+	MOVD	R7, R6
+	MOVD	R8, R7
+#else
 	MOVD	num+0(FP), R1	// syscall entry
 	MOVD	a1+8(FP), R2
 	MOVD	a2+16(FP), R3
@@ -13,16 +22,27 @@ TEXT ·Syscall6(SB),NOSPLIT,$0-80
 	MOVD	a4+32(FP), R5
 	MOVD	a5+40(FP), R6
 	MOVD	a6+48(FP), R7
+#endif
 	SYSCALL
 	MOVD	$0xfffffffffffff001, R8
 	CMPUBLT	R2, R8, ok
+#ifdef GOEXPERIMENT_regabiargs
+	MOVD	$0, R3
+	NEG	R2, R4
+	MOVD    $-1, R2
+#else
 	MOVD	$-1, r1+56(FP)
 	MOVD	$0, r2+64(FP)
 	NEG	R2, R2
 	MOVD	R2, errno+72(FP)
+#endif
 	RET
 ok:
+#ifdef GOEXPERIMENT_regabiargs
+	MOVD	$0, R4
+#else
 	MOVD	R2, r1+56(FP)
 	MOVD	R3, r2+64(FP)
 	MOVD	$0, errno+72(FP)
+#endif
 	RET
-- 
2.52.0