From 160d7972607d5c630c7cfd1b4b54f7c27c3387b1 Mon Sep 17 00:00:00 2001
From: Joel Sing <joel@sing.id.au>
Date: Sat, 29 May 2021 04:06:56 +1000
Subject: [PATCH] runtime: correct mips64 asmcgocall signal stack behaviour

Do not switch to the g0 stack if we're already running on the signal
stack, otherwise all kind of fun ensues.

Updates #36435

Change-Id: I57f35d75b9ee4f92b997713b4cdd38ce881705e6
Reviewed-on: https://go-review.googlesource.com/c/go/+/334880
Trust: Joel Sing <joel@sing.id.au>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cherry Mui <cherryyz@google.com>
---
 src/runtime/asm_mips64x.s | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/runtime/asm_mips64x.s b/src/runtime/asm_mips64x.s
index b2e2384c36..940a38a0d6 100644
--- a/src/runtime/asm_mips64x.s
+++ b/src/runtime/asm_mips64x.s
@@ -426,6 +426,8 @@ TEXT ·asmcgocall(SB),NOSPLIT,$0-20
 	// We get called to create new OS threads too, and those
 	// come in on the m->g0 stack already.
 	MOVV	g_m(g), R5
+	MOVV	m_gsignal(R5), R6
+	BEQ	R6, g, g0
 	MOVV	m_g0(R5), R6
 	BEQ	R6, g, g0