--- zzzz-none-000/linux-3.10.107/arch/s390/kernel/base.S	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/arch/s390/kernel/base.S	2021-02-04 17:41:59.000000000 +0000
@@ -11,8 +11,6 @@
 #include <asm/ptrace.h>
 #include <asm/sigp.h>
 
-#ifdef CONFIG_64BIT
-
 ENTRY(s390_base_mcck_handler)
 	basr	%r13,0
 0:	lg	%r15,__LC_PANIC_STACK	# load panic stack
@@ -80,15 +78,20 @@
 #
 # Calls diag 308 subcode 1 and continues execution
 #
-# The following conditions must be ensured before calling this function:
-# * Prefix register = 0
-# * Lowcore protection is disabled
-#
 ENTRY(diag308_reset)
 	larl	%r4,.Lctlregs		# Save control registers
 	stctg	%c0,%c15,0(%r4)
+	lg	%r2,0(%r4)		# Disable lowcore protection
+	nilh	%r2,0xefff
+	larl	%r4,.Lctlreg0
+	stg	%r2,0(%r4)
+	lctlg	%c0,%c0,0(%r4)
 	larl	%r4,.Lfpctl		# Floating point control register
 	stfpc	0(%r4)
+	larl	%r4,.Lprefix		# Save prefix register
+	stpx	0(%r4)
+	larl	%r4,.Lprefix_zero	# Set prefix register to 0
+	spx	0(%r4)
 	larl	%r4,.Lcontinue_psw	# Save PSW flags
 	epsw	%r2,%r3
 	stm	%r2,%r3,0(%r4)
@@ -97,7 +100,8 @@
 	lg	%r4,0(%r4)		# Save PSW
 	sturg	%r4,%r3			# Use sturg, because of large pages
 	lghi	%r1,1
-	diag	%r1,%r1,0x308
+	lghi	%r0,0
+	diag	%r0,%r1,0x308
 .Lrestart_part2:
 	lhi	%r0,0			# Load r0 with zero
 	lhi	%r1,2			# Use mode 2 = ESAME (dump)
@@ -107,6 +111,8 @@
 	lctlg	%c0,%c15,0(%r4)
 	larl	%r4,.Lfpctl		# Restore floating point ctl register
 	lfpc	0(%r4)
+	larl	%r4,.Lprefix		# Restore prefix register
+	spx	0(%r4)
 	larl	%r4,.Lcontinue_psw	# Restore PSW flags
 	lpswe	0(%r4)
 .Lcontinue:
@@ -123,84 +129,16 @@
 
 	.section .bss
 .align 8
+.Lctlreg0:
+	.quad	0
 .Lctlregs:
 	.rept	16
 	.quad	0
 	.endr
 .Lfpctl:
 	.long	0
-	.previous
-
-#else /* CONFIG_64BIT */
-
-ENTRY(s390_base_mcck_handler)
-	basr	%r13,0
-0:	l	%r15,__LC_PANIC_STACK	# load panic stack
-	ahi	%r15,-STACK_FRAME_OVERHEAD
-	l	%r1,2f-0b(%r13)
-	l	%r1,0(%r1)
-	ltr	%r1,%r1
-	jz	1f
-	basr	%r14,%r1
-1:	lm	%r0,%r15,__LC_GPREGS_SAVE_AREA
-	lpsw	__LC_MCK_OLD_PSW
-
-2:	.long	s390_base_mcck_handler_fn
-
-	.section .bss
-	.align 4
-	.globl	s390_base_mcck_handler_fn
-s390_base_mcck_handler_fn:
-	.long	0
-	.previous
-
-ENTRY(s390_base_ext_handler)
-	stm	%r0,%r15,__LC_SAVE_AREA_ASYNC
-	basr	%r13,0
-0:	ahi	%r15,-STACK_FRAME_OVERHEAD
-	l	%r1,2f-0b(%r13)
-	l	%r1,0(%r1)
-	ltr	%r1,%r1
-	jz	1f
-	basr	%r14,%r1
-1:	lm	%r0,%r15,__LC_SAVE_AREA_ASYNC
-	ni	__LC_EXT_OLD_PSW+1,0xfd	# clear wait state bit
-	lpsw	__LC_EXT_OLD_PSW
-
-2:	.long	s390_base_ext_handler_fn
-
-	.section .bss
-	.align 4
-	.globl	s390_base_ext_handler_fn
-s390_base_ext_handler_fn:
+.Lprefix:
 	.long	0
-	.previous
-
-ENTRY(s390_base_pgm_handler)
-	stm	%r0,%r15,__LC_SAVE_AREA_SYNC
-	basr	%r13,0
-0:	ahi	%r15,-STACK_FRAME_OVERHEAD
-	l	%r1,2f-0b(%r13)
-	l	%r1,0(%r1)
-	ltr	%r1,%r1
-	jz	1f
-	basr	%r14,%r1
-	lm	%r0,%r15,__LC_SAVE_AREA_SYNC
-	lpsw	__LC_PGM_OLD_PSW
-
-1:	lpsw	disabled_wait_psw-0b(%r13)
-
-2:	.long	s390_base_pgm_handler_fn
-
-disabled_wait_psw:
-	.align	8
-	.long	0x000a0000,0x00000000 + s390_base_pgm_handler
-
-	.section .bss
-	.align 4
-	.globl	s390_base_pgm_handler_fn
-s390_base_pgm_handler_fn:
+.Lprefix_zero:
 	.long	0
 	.previous
-
-#endif /* CONFIG_64BIT */