From 3fe733f3755acef0a48f2d6360d52cc54310359d Mon Sep 17 00:00:00 2001
From: Alex Richardson <arichardson@FreeBSD.org>
Date: Fri, 5 Jun 2020 08:46:55 +0000
Subject: [PATCH] csu: Avoid additional nops in the MIPS INIT_CALL_SEQ macro

Since we had a .set reorder, the nop after the "jal" was being placed after
the delay slot, resulting in two nops.
While changing this code also guard the .set noreorder with .set push/pop
and use $zero as the cpsetup save register since we don't need to save $gp.

Reviewed By:	jhb
Differential Revision: https://reviews.freebsd.org/D25025
---
 lib/csu/mips/crt.h | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/lib/csu/mips/crt.h b/lib/csu/mips/crt.h
index b1250e02c4eb..b7bf991cf991 100644
--- a/lib/csu/mips/crt.h
+++ b/lib/csu/mips/crt.h
@@ -30,29 +30,31 @@
 #define	CTORS_CONSTRUCTORS
 #ifdef __mips_o32
 #define	INIT_CALL_SEQ(func)						\
+    ".set push			\n"					\
     ".set noreorder		\n"					\
     "bal	1f		\n"					\
     "nop			\n"					\
     "1:				\n"					\
     ".cpload	$ra		\n"					\
     "addu	$sp, $sp, -8	\n"					\
-    ".set reorder		\n"					\
     ".cprestore	4		\n"					\
     ".local	" __STRING(func) "\n"					\
     "jal	" __STRING(func) "\n"					\
     "nop			\n"					\
-    "addu	$sp, $sp, 8	\n"
+    "addu	$sp, $sp, 8	\n"					\
+    ".set pop\n"
 #else
 #define	INIT_CALL_SEQ(func)						\
+    ".set push			\n"					\
     ".set noreorder		\n"					\
     "bal	1f		\n"					\
     "nop			\n"					\
     "1:				\n"					\
-    ".set reorder		\n"					\
-    ".cpsetup $ra, $v0, 1b	\n"					\
+    ".cpsetup $ra, $zero, 1b	\n"					\
     ".local	" __STRING(func) "\n"					\
     "jal	" __STRING(func) "\n"					\
-    "nop			\n"
+    "nop			\n"					\
+    ".set pop\n"
 #endif
 
 #endif