>From 6182ff1f35675c60c201be73e60654c15af77c2f Mon Sep 17 00:00:00 2001
From: Rich Felker <dalias@aerifal.cx>
Date: Wed, 11 Mar 2020 18:50:21 -0400
Subject: [PATCH 2/4] revert previous changes to mips (32-bit, o32) syscall asm

exactly revert commit 604f8d3d8b08ee4f548de193050ef93a7753c2e0. it's
wrong for the same reason as a6ab25ff9885a810c8ceba42b9b1ea3badaae879
but does not have to deal with conflicting changes since.

improvements that were valid will be added back as a separate commit.
---
 arch/mips/syscall_arch.h | 63 ++++++++++++++++++++--------------------
 1 file changed, 31 insertions(+), 32 deletions(-)

diff --git a/arch/mips/syscall_arch.h b/arch/mips/syscall_arch.h
index f821e73f..a3812188 100644
--- a/arch/mips/syscall_arch.h
+++ b/arch/mips/syscall_arch.h
@@ -18,11 +18,10 @@
 static inline long __syscall0(long n)
 {
 	register long r7 __asm__("$7");
-	register long r2 __asm__("$2") = n;
+	register long r2 __asm__("$2");
 	__asm__ __volatile__ (
-		"syscall"
-		: "+r"(r2), "=r"(r7)
-		:
+		"addu $2,$0,%2 ; syscall"
+		: "=&r"(r2), "=r"(r7) : "ir"(n), "0"(r2), "1"(r7)
 		: SYSCALL_CLOBBERLIST, "$8", "$9", "$10");
 	return r7 ? -r2 : r2;
 }
@@ -31,11 +30,11 @@ static inline long __syscall1(long n, long a)
 {
 	register long r4 __asm__("$4") = a;
 	register long r7 __asm__("$7");
-	register long r2 __asm__("$2") = n;
+	register long r2 __asm__("$2");
 	__asm__ __volatile__ (
-		"syscall"
-		: "+r"(r2), "=r"(r7)
-		: "r"(r4)
+		"addu $2,$0,%2 ; syscall"
+		: "=&r"(r2), "=r"(r7) : "ir"(n), "0"(r2), "1"(r7),
+		  "r"(r4)
 		: SYSCALL_CLOBBERLIST, "$8", "$9", "$10");
 	return r7 ? -r2 : r2;
 }
@@ -45,11 +44,11 @@ static inline long __syscall2(long n, long a, long b)
 	register long r4 __asm__("$4") = a;
 	register long r5 __asm__("$5") = b;
 	register long r7 __asm__("$7");
-	register long r2 __asm__("$2") = n;
+	register long r2 __asm__("$2");
 	__asm__ __volatile__ (
-		"syscall"
-		: "+r"(r2), "=r"(r7)
-		: "r"(r4), "r"(r5)
+		"addu $2,$0,%2 ; syscall"
+		: "=&r"(r2), "=r"(r7) : "ir"(n), "0"(r2), "1"(r7),
+		  "r"(r4), "r"(r5)
 		: SYSCALL_CLOBBERLIST, "$8", "$9", "$10");
 	return r7 ? -r2 : r2;
 }
@@ -60,11 +59,11 @@ static inline long __syscall3(long n, long a, long b, long c)
 	register long r5 __asm__("$5") = b;
 	register long r6 __asm__("$6") = c;
 	register long r7 __asm__("$7");
-	register long r2 __asm__("$2") = n;
+	register long r2 __asm__("$2");
 	__asm__ __volatile__ (
-		"syscall"
-		: "+r"(r2), "=r"(r7)
-		: "r"(r4), "r"(r5), "r"(r6)
+		"addu $2,$0,%2 ; syscall"
+		: "=&r"(r2), "=r"(r7) : "ir"(n), "0"(r2), "1"(r7),
+		  "r"(r4), "r"(r5), "r"(r6)
 		: SYSCALL_CLOBBERLIST, "$8", "$9", "$10");
 	return r7 ? -r2 : r2;
 }
@@ -75,11 +74,11 @@ static inline long __syscall4(long n, long a, long b, long c, long d)
 	register long r5 __asm__("$5") = b;
 	register long r6 __asm__("$6") = c;
 	register long r7 __asm__("$7") = d;
-	register long r2 __asm__("$2") = n;
+	register long r2 __asm__("$2");
 	__asm__ __volatile__ (
-		"syscall"
-		: "+r"(r2), "+r"(r7)
-		: "r"(r4), "r"(r5), "r"(r6)
+		"addu $2,$0,%2 ; syscall"
+		: "=&r"(r2), "=r"(r7) : "ir"(n), "0"(r2), "1"(r7),
+		  "r"(r4), "r"(r5), "r"(r6)
 		: SYSCALL_CLOBBERLIST, "$8", "$9", "$10");
 	return r7 ? -r2 : r2;
 }
@@ -91,13 +90,13 @@ static inline long __syscall5(long n, long a, long b, long c, long d, long e)
 	register long r6 __asm__("$6") = c;
 	register long r7 __asm__("$7") = d;
 	register long r8 __asm__("$8") = e;
-	register long r2 __asm__("$2") = n;
+	register long r2 __asm__("$2");
 	__asm__ __volatile__ (
 		"subu $sp,$sp,32 ; sw $8,16($sp) ; "
-		"syscall ;"
+		"addu $2,$0,%3 ; syscall ;"
 		"addu $sp,$sp,32"
-		: "+r"(r2), "+r"(r7), "+r"(r8)
-		: "r"(r4), "r"(r5), "r"(r6)
+		: "=&r"(r2), "=r"(r7), "+r"(r8)
+		: "ir"(n), "0"(r2), "1"(r7), "r"(r4), "r"(r5), "r"(r6)
 		: SYSCALL_CLOBBERLIST, "$9", "$10");
 	return r7 ? -r2 : r2;
 }
@@ -110,13 +109,13 @@ static inline long __syscall6(long n, long a, long b, long c, long d, long e, lo
 	register long r7 __asm__("$7") = d;
 	register long r8 __asm__("$8") = e;
 	register long r9 __asm__("$9") = f;
-	register long r2 __asm__("$2") = n;
+	register long r2 __asm__("$2");
 	__asm__ __volatile__ (
 		"subu $sp,$sp,32 ; sw $8,16($sp) ; sw $9,20($sp) ; "
-		"syscall ;"
+		"addu $2,$0,%4 ; syscall ;"
 		"addu $sp,$sp,32"
-		: "+r"(r2), "+r"(r7), "+r"(r8), "+r"(r9)
-		: "r"(r4), "r"(r5), "r"(r6)
+		: "=&r"(r2), "=r"(r7), "+r"(r8), "+r"(r9)
+		: "ir"(n), "0"(r2), "1"(r7), "r"(r4), "r"(r5), "r"(r6)
 		: SYSCALL_CLOBBERLIST, "$10");
 	return r7 ? -r2 : r2;
 }
@@ -130,13 +129,13 @@ static inline long __syscall7(long n, long a, long b, long c, long d, long e, lo
 	register long r8 __asm__("$8") = e;
 	register long r9 __asm__("$9") = f;
 	register long r10 __asm__("$10") = g;
-	register long r2 __asm__("$2") = n;
+	register long r2 __asm__("$2");
 	__asm__ __volatile__ (
 		"subu $sp,$sp,32 ; sw $8,16($sp) ; sw $9,20($sp) ; sw $10,24($sp) ; "
-		"syscall ;"
+		"addu $2,$0,%5 ; syscall ;"
 		"addu $sp,$sp,32"
-		: "+r"(r2), "+r"(r7), "+r"(r8), "+r"(r9), "+r"(r10)
-		: "r"(r4), "r"(r5), "r"(r6)
+		: "=&r"(r2), "=r"(r7), "+r"(r8), "+r"(r9), "+r"(r10)
+		: "ir"(n), "0"(r2), "1"(r7), "r"(r4), "r"(r5), "r"(r6)
 		: SYSCALL_CLOBBERLIST);
 	return r7 ? -r2 : r2;
 }
-- 
2.21.0