--- zzzz-none-000/linux-3.10.107/arch/arm/kernel/swp_emulate.c	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/arch/arm/kernel/swp_emulate.c	2021-02-04 17:41:59.000000000 +0000
@@ -27,6 +27,7 @@
 #include <linux/perf_event.h>
 
 #include <asm/opcodes.h>
+#include <asm/system_info.h>
 #include <asm/traps.h>
 #include <asm/uaccess.h>
 
@@ -35,13 +36,13 @@
  */
 #define __user_swpX_asm(data, addr, res, temp, B)		\
 	__asm__ __volatile__(					\
-	"	mov		%2, %1\n"			\
-	"0:	ldrex"B"	%1, [%3]\n"			\
-	"1:	strex"B"	%0, %2, [%3]\n"			\
+	"0:	ldrex"B"	%2, [%3]\n"			\
+	"1:	strex"B"	%0, %1, [%3]\n"			\
 	"	cmp		%0, #0\n"			\
+	"	moveq		%1, %2\n"			\
 	"	movne		%0, %4\n"			\
 	"2:\n"							\
-	"	.section	 .fixup,\"ax\"\n"		\
+	"	.section	 .text.fixup,\"ax\"\n"		\
 	"	.align		2\n"				\
 	"3:	mov		%0, %5\n"			\
 	"	b		2b\n"				\
@@ -140,19 +141,14 @@
 
 	while (1) {
 		unsigned long temp;
+		unsigned int __ua_flags;
 
-		/*
-		 * Barrier required between accessing protected resource and
-		 * releasing a lock for it. Legacy code might not have done
-		 * this, and we cannot determine that this is not the case
-		 * being emulated, so insert always.
-		 */
-		smp_mb();
-
+		__ua_flags = uaccess_save_and_enable();
 		if (type == TYPE_SWPB)
 			__user_swpb_asm(*data, address, res, temp);
 		else
 			__user_swp_asm(*data, address, res, temp);
+		uaccess_restore(__ua_flags);
 
 		if (likely(res != -EAGAIN) || signal_pending(current))
 			break;
@@ -161,13 +157,6 @@
 	}
 
 	if (res == 0) {
-		/*
-		 * Barrier also required between acquiring a lock for a
-		 * protected resource and accessing the resource. Inserted for
-		 * same reason as above.
-		 */
-		smp_mb();
-
 		if (type == TYPE_SWPB)
 			swpbcounter++;
 		else
@@ -266,12 +255,15 @@
  */
 static int __init swp_emulation_init(void)
 {
+	if (cpu_architecture() < CPU_ARCH_ARMv7)
+		return 0;
+
 #ifdef CONFIG_PROC_FS
 	if (!proc_create("cpu/swp_emulation", S_IRUGO, NULL, &proc_status_fops))
 		return -ENOMEM;
 #endif /* CONFIG_PROC_FS */
 
-	printk(KERN_NOTICE "Registering SWP/SWPB emulation handler\n");
+	pr_notice("Registering SWP/SWPB emulation handler\n");
 	register_undef_hook(&swp_hook);
 
 	return 0;