From b5c8ae9816e705f2202242de9d570a33dabd3a0a Mon Sep 17 00:00:00 2001
From: Guoqi Chen <chenguoqi@loongson.cn>
Date: Fri, 4 Nov 2022 13:27:23 +0800
Subject: [PATCH] runtime: mark morestack_noctxt SPWRITE for linux/loong64

ref. CL 425396

Updates #54332.

Change-Id: I1a235b0cca4dbf79cf61cf5f40b594fc2d940857
Reviewed-on: https://go-review.googlesource.com/c/go/+/446895
Reviewed-by: Cherry Mui <cherryyz@google.com>
Reviewed-by: WANG Xuerui <git@xen0n.name>
Run-TryBot: Wayne Zuo <wdvxdr@golangcn.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Reviewed-by: xiaodong liu <teaofmoli@gmail.com>
---
 src/runtime/asm_loong64.s | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/src/runtime/asm_loong64.s b/src/runtime/asm_loong64.s
index 2513d2bb54..60641d0aee 100644
--- a/src/runtime/asm_loong64.s
+++ b/src/runtime/asm_loong64.s
@@ -266,6 +266,13 @@ TEXT runtime·morestack(SB),NOSPLIT|NOFRAME,$0-0
 	UNDEF
 
 TEXT runtime·morestack_noctxt(SB),NOSPLIT|NOFRAME,$0-0
+	// Force SPWRITE. This function doesn't actually write SP,
+	// but it is called with a special calling convention where
+	// the caller doesn't save LR on stack but passes it as a
+	// register (R5), and the unwinder currently doesn't understand.
+	// Make it SPWRITE to stop unwinding. (See issue 54332)
+	MOVV    R3, R3
+
 	MOVV	R0, REGCTXT
 	JMP	runtime·morestack(SB)
 
-- 
2.50.0