[S390] 31 bit entry.S update.

Make the code in the 31 bit entry.S code as similar as possible to the
64 bit version in entry64.S. That makes it easier to add new code to
the first level interrupt handler that affects both 31 and 64 bit kernels.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/kernel/entry.S

@@ -9,7 +9,6 @@
  *		 Heiko Carstens <heiko.carstens@de.ibm.com>
  */
 
-#include <linux/sys.h>
 #include <linux/linkage.h>
 #include <linux/init.h>
 #include <asm/cache.h>
@@ -110,31 +109,36 @@ STACK_SIZE  = 1 << STACK_SHIFT
 1:	stm	%r10,%r11,\lc_sum
 	.endm
 
-	.macro	SAVE_ALL_BASE savearea
+	.macro	SAVE_ALL_SVC psworg,savearea
 	stm	%r12,%r15,\savearea
 	l	%r13,__LC_SVC_NEW_PSW+4	# load &system_call to %r13
+	l	%r15,__LC_KERNEL_STACK	# problem state -> load ksp
+	s	%r15,BASED(.Lc_spsize)	# make room for registers & psw
 	.endm
 
-	.macro	SAVE_ALL_SVC psworg,savearea
-	la	%r12,\psworg
-	l	%r15,__LC_KERNEL_STACK	# problem state -> load ksp
+	.macro	SAVE_ALL_BASE savearea
+	stm	%r12,%r15,\savearea
+	l	%r13,__LC_SVC_NEW_PSW+4	# load &system_call to %r13
 	.endm
 
-	.macro	SAVE_ALL_SYNC psworg,savearea
-	la	%r12,\psworg
+	.macro	SAVE_ALL_PGM psworg,savearea
 	tm	\psworg+1,0x01		# test problem state bit
-	bz	BASED(2f)		# skip stack setup save
-	l	%r15,__LC_KERNEL_STACK	# problem state -> load ksp
 #ifdef CONFIG_CHECK_STACK
-	b	BASED(3f)
-2:	tml	%r15,STACK_SIZE - CONFIG_STACK_GUARD
-	bz	BASED(stack_overflow)
-3:
+	bnz	BASED(1f)
+	tml	%r15,STACK_SIZE - CONFIG_STACK_GUARD
+	bnz	BASED(2f)
+	la	%r12,\psworg
+	b	BASED(stack_overflow)
+#else
+	bz	BASED(2f)
 #endif
-2:
+1:	l	%r15,__LC_KERNEL_STACK	# problem state -> load ksp
+2:	s	%r15,BASED(.Lc_spsize)	# make room for registers & psw
 	.endm
 
 	.macro	SAVE_ALL_ASYNC psworg,savearea
+	stm	%r12,%r15,\savearea
+	l	%r13,__LC_SVC_NEW_PSW+4	# load &system_call to %r13
 	la	%r12,\psworg
 	tm	\psworg+1,0x01		# test problem state bit
 	bnz	BASED(1f)		# from user -> load async stack
@@ -149,27 +153,23 @@ STACK_SIZE  = 1 << STACK_SHIFT
 0:	l	%r14,__LC_ASYNC_STACK	# are we already on the async stack ?
 	slr	%r14,%r15
 	sra	%r14,STACK_SHIFT
-	be	BASED(2f)
-1:	l	%r15,__LC_ASYNC_STACK
 #ifdef CONFIG_CHECK_STACK
-	b	BASED(3f)
-2:	tml	%r15,STACK_SIZE - CONFIG_STACK_GUARD
-	bz	BASED(stack_overflow)
-3:
+	bnz	BASED(1f)
+	tml	%r15,STACK_SIZE - CONFIG_STACK_GUARD
+	bnz	BASED(2f)
+	b	BASED(stack_overflow)
+#else
+	bz	BASED(2f)
 #endif
-2:
+1:	l	%r15,__LC_ASYNC_STACK
+2:	s	%r15,BASED(.Lc_spsize)	# make room for registers & psw
 	.endm
 
-	.macro	CREATE_STACK_FRAME psworg,savearea
-	s	%r15,BASED(.Lc_spsize)	# make room for registers & psw
-	mvc	SP_PSW(8,%r15),0(%r12)	# move user PSW to stack
+	.macro	CREATE_STACK_FRAME savearea
+	xc	__SF_BACKCHAIN(4,%r15),__SF_BACKCHAIN(%r15)
 	st	%r2,SP_ORIG_R2(%r15)	# store original content of gpr 2
-	icm	%r12,12,__LC_SVC_ILC
-	stm	%r0,%r11,SP_R0(%r15)	# store gprs %r0-%r11 to kernel stack
-	st	%r12,SP_ILC(%r15)
 	mvc	SP_R12(16,%r15),\savearea # move %r12-%r15 to stack
-	la	%r12,0
-	st	%r12,__SF_BACKCHAIN(%r15)	# clear back chain
+	stm	%r0,%r11,SP_R0(%r15)	# store gprs %r0-%r11 to kernel stack
 	.endm
 
 	.macro	RESTORE_ALL psworg,sync
@@ -237,10 +237,11 @@ __critical_start:
 system_call:
 	stpt	__LC_SYNC_ENTER_TIMER
 sysc_saveall:
-	SAVE_ALL_BASE __LC_SAVE_AREA
 	SAVE_ALL_SVC __LC_SVC_OLD_PSW,__LC_SAVE_AREA
-	CREATE_STACK_FRAME __LC_SVC_OLD_PSW,__LC_SAVE_AREA
-	lh	%r7,0x8a	  # get svc number from lowcore
+	CREATE_STACK_FRAME __LC_SAVE_AREA
+	mvc	SP_PSW(8,%r15),__LC_SVC_OLD_PSW
+	mvc	SP_ILC(4,%r15),__LC_SVC_ILC
+	l	%r12,__LC_THREAD_INFO	# load pointer to thread_info struct
 sysc_vtime:
 	UPDATE_VTIME __LC_EXIT_TIMER,__LC_SYNC_ENTER_TIMER,__LC_USER_TIMER
 sysc_stime:
@@ -248,20 +249,20 @@ sysc_stime:
 sysc_update:
 	mvc	__LC_LAST_UPDATE_TIMER(8),__LC_SYNC_ENTER_TIMER
 sysc_do_svc:
-	l	%r9,__LC_THREAD_INFO	# load pointer to thread_info struct
-	ltr	%r7,%r7			# test for svc 0
+	xr	%r7,%r7
+	icm	%r7,3,SP_SVCNR(%r15)	# load svc number and test for svc 0
 	bnz	BASED(sysc_nr_ok)	# svc number > 0
 	# svc 0: system call number in %r1
 	cl	%r1,BASED(.Lnr_syscalls)
 	bnl	BASED(sysc_nr_ok)
+	sth	%r1,SP_SVCNR(%r15)
 	lr	%r7,%r1 	  # copy svc number to %r7
 sysc_nr_ok:
-	sth	%r7,SP_SVCNR(%r15)
 	sll	%r7,2		  # svc number *4
-	l	%r8,BASED(.Lsysc_table)
-	tm	__TI_flags+2(%r9),_TIF_SYSCALL
+	l	%r10,BASED(.Lsysc_table)
+	tm	__TI_flags+2(%r12),_TIF_SYSCALL
 	mvc	SP_ARGS(4,%r15),SP_R7(%r15)
-	l	%r8,0(%r7,%r8)	  # get system call addr.
+	l	%r8,0(%r7,%r10)	  # get system call addr.
 	bnz	BASED(sysc_tracesys)
 	basr	%r14,%r8	  # call sys_xxxx
 	st	%r2,SP_R2(%r15)   # store return value (change R2 on stack)
@@ -269,7 +270,7 @@ sysc_nr_ok:
 sysc_return:
 	LOCKDEP_SYS_EXIT
 sysc_tif:
-	tm	__TI_flags+3(%r9),_TIF_WORK_SVC
+	tm	__TI_flags+3(%r12),_TIF_WORK_SVC
 	bnz	BASED(sysc_work)  # there is work to do (signals etc.)
 sysc_restore:
 	RESTORE_ALL __LC_RETURN_PSW,1
@@ -286,17 +287,17 @@ sysc_work:
 # One of the work bits is on. Find out which one.
 #
 sysc_work_tif:
-	tm	__TI_flags+3(%r9),_TIF_MCCK_PENDING
+	tm	__TI_flags+3(%r12),_TIF_MCCK_PENDING
 	bo	BASED(sysc_mcck_pending)
-	tm	__TI_flags+3(%r9),_TIF_NEED_RESCHED
+	tm	__TI_flags+3(%r12),_TIF_NEED_RESCHED
 	bo	BASED(sysc_reschedule)
-	tm	__TI_flags+3(%r9),_TIF_SIGPENDING
+	tm	__TI_flags+3(%r12),_TIF_SIGPENDING
 	bo	BASED(sysc_sigpending)
-	tm	__TI_flags+3(%r9),_TIF_NOTIFY_RESUME
+	tm	__TI_flags+3(%r12),_TIF_NOTIFY_RESUME
 	bo	BASED(sysc_notify_resume)
-	tm	__TI_flags+3(%r9),_TIF_RESTART_SVC
+	tm	__TI_flags+3(%r12),_TIF_RESTART_SVC
 	bo	BASED(sysc_restart)
-	tm	__TI_flags+3(%r9),_TIF_SINGLE_STEP
+	tm	__TI_flags+3(%r12),_TIF_SINGLE_STEP
 	bo	BASED(sysc_singlestep)
 	b	BASED(sysc_return)	# beware of critical section cleanup
 
@@ -320,13 +321,13 @@ sysc_mcck_pending:
 # _TIF_SIGPENDING is set, call do_signal
 #
 sysc_sigpending:
-	ni	__TI_flags+3(%r9),255-_TIF_SINGLE_STEP # clear TIF_SINGLE_STEP
+	ni	__TI_flags+3(%r12),255-_TIF_SINGLE_STEP # clear TIF_SINGLE_STEP
 	la	%r2,SP_PTREGS(%r15)	# load pt_regs
 	l	%r1,BASED(.Ldo_signal)
 	basr	%r14,%r1		# call do_signal
-	tm	__TI_flags+3(%r9),_TIF_RESTART_SVC
+	tm	__TI_flags+3(%r12),_TIF_RESTART_SVC
 	bo	BASED(sysc_restart)
-	tm	__TI_flags+3(%r9),_TIF_SINGLE_STEP
+	tm	__TI_flags+3(%r12),_TIF_SINGLE_STEP
 	bo	BASED(sysc_singlestep)
 	b	BASED(sysc_return)
 
@@ -344,19 +345,19 @@ sysc_notify_resume:
 # _TIF_RESTART_SVC is set, set up registers and restart svc
 #
 sysc_restart:
-	ni	__TI_flags+3(%r9),255-_TIF_RESTART_SVC # clear TIF_RESTART_SVC
+	ni	__TI_flags+3(%r12),255-_TIF_RESTART_SVC # clear TIF_RESTART_SVC
 	l	%r7,SP_R2(%r15) 	# load new svc number
 	mvc	SP_R2(4,%r15),SP_ORIG_R2(%r15) # restore first argument
 	lm	%r2,%r6,SP_R2(%r15)	# load svc arguments
+	sth	%r7,SP_SVCNR(%r15)
 	b	BASED(sysc_nr_ok)	# restart svc
 
 #
 # _TIF_SINGLE_STEP is set, call do_single_step
 #
 sysc_singlestep:
-	ni	__TI_flags+3(%r9),255-_TIF_SINGLE_STEP # clear TIF_SINGLE_STEP
-	mvi	SP_SVCNR(%r15),0xff	# set trap indication to pgm check
-	mvi	SP_SVCNR+1(%r15),0xff
+	ni	__TI_flags+3(%r12),255-_TIF_SINGLE_STEP # clear TIF_SINGLE_STEP
+	xc	SP_SVCNR(2,%r15),SP_SVCNR(%r15)		# clear svc number
 	la	%r2,SP_PTREGS(%r15)	# address of register-save area
 	l	%r1,BASED(.Lhandle_per)	# load adr. of per handler
 	la	%r14,BASED(sysc_return)	# load adr. of system return
@@ -370,15 +371,15 @@ sysc_tracesys:
 	l	%r1,BASED(.Ltrace_entry)
 	la	%r2,SP_PTREGS(%r15)	# load pt_regs
 	la	%r3,0
-	srl	%r7,2
-	st	%r7,SP_R2(%r15)
+	xr	%r0,%r0
+	icm	%r0,3,SP_SVCNR(%r15)
+	st	%r0,SP_R2(%r15)
 	basr	%r14,%r1
 	cl	%r2,BASED(.Lnr_syscalls)
 	bnl	BASED(sysc_tracenogo)
-	l	%r8,BASED(.Lsysc_table)
 	lr	%r7,%r2
 	sll	%r7,2			# svc number *4
-	l	%r8,0(%r7,%r8)
+	l	%r8,0(%r7,%r10)
 sysc_tracego:
 	lm	%r3,%r6,SP_R3(%r15)
 	mvc	SP_ARGS(4,%r15),SP_R7(%r15)
@@ -386,7 +387,7 @@ sysc_tracego:
 	basr	%r14,%r8		# call sys_xxx
 	st	%r2,SP_R2(%r15)		# store return value
 sysc_tracenogo:
-	tm	__TI_flags+2(%r9),_TIF_SYSCALL
+	tm	__TI_flags+2(%r12),_TIF_SYSCALL
 	bz	BASED(sysc_return)
 	l	%r1,BASED(.Ltrace_exit)
 	la	%r2,SP_PTREGS(%r15)	# load pt_regs
@@ -399,7 +400,7 @@ sysc_tracenogo:
 	.globl	ret_from_fork
 ret_from_fork:
 	l	%r13,__LC_SVC_NEW_PSW+4
-	l	%r9,__LC_THREAD_INFO	# load pointer to thread_info struct
+	l	%r12,__LC_THREAD_INFO	# load pointer to thread_info struct
 	tm	SP_PSW+1(%r15),0x01	# forking a kernel thread ?
 	bo	BASED(0f)
 	st	%r15,SP_R15(%r15)	# store stack pointer for new kthread
@@ -434,8 +435,8 @@ kernel_execve:
 0:	stnsm	__SF_EMPTY(%r15),0xfc	# disable interrupts
 	l	%r15,__LC_KERNEL_STACK	# load ksp
 	s	%r15,BASED(.Lc_spsize)	# make room for registers & psw
-	l	%r9,__LC_THREAD_INFO
 	mvc	SP_PTREGS(__PT_SIZE,%r15),0(%r12)	# copy pt_regs
+	l	%r12,__LC_THREAD_INFO
 	xc	__SF_BACKCHAIN(4,%r15),__SF_BACKCHAIN(%r15)
 	stosm	__SF_EMPTY(%r15),0x03	# reenable interrupts
 	l	%r1,BASED(.Lexecve_tail)
@@ -465,26 +466,27 @@ pgm_check_handler:
 	SAVE_ALL_BASE __LC_SAVE_AREA
 	tm	__LC_PGM_INT_CODE+1,0x80 # check whether we got a per exception
 	bnz	BASED(pgm_per)		# got per exception -> special case
-	SAVE_ALL_SYNC __LC_PGM_OLD_PSW,__LC_SAVE_AREA
-	CREATE_STACK_FRAME __LC_PGM_OLD_PSW,__LC_SAVE_AREA
+	SAVE_ALL_PGM __LC_PGM_OLD_PSW,__LC_SAVE_AREA
+	CREATE_STACK_FRAME __LC_SAVE_AREA
+	xc	SP_ILC(4,%r15),SP_ILC(%r15)
+	mvc	SP_PSW(8,%r15),__LC_PGM_OLD_PSW
+	l	%r12,__LC_THREAD_INFO	# load pointer to thread_info struct
 	tm	SP_PSW+1(%r15),0x01	# interrupting from user ?
 	bz	BASED(pgm_no_vtime)
 	UPDATE_VTIME __LC_EXIT_TIMER,__LC_SYNC_ENTER_TIMER,__LC_USER_TIMER
 	UPDATE_VTIME __LC_LAST_UPDATE_TIMER,__LC_EXIT_TIMER,__LC_SYSTEM_TIMER
 	mvc	__LC_LAST_UPDATE_TIMER(8),__LC_SYNC_ENTER_TIMER
 pgm_no_vtime:
-	l	%r9,__LC_THREAD_INFO	# load pointer to thread_info struct
 	l	%r3,__LC_PGM_ILC	# load program interruption code
 	l	%r4,__LC_TRANS_EXC_CODE
 	REENABLE_IRQS
 	la	%r8,0x7f
 	nr	%r8,%r3
-pgm_do_call:
-	l	%r7,BASED(.Ljump_table)
 	sll	%r8,2
-	l	%r7,0(%r8,%r7)		# load address of handler routine
+	l	%r1,BASED(.Ljump_table)
+	l	%r1,0(%r8,%r1)		# load address of handler routine
 	la	%r2,SP_PTREGS(%r15)	# address of register-save area
-	basr	%r14,%r7		# branch to interrupt-handler
+	basr	%r14,%r1		# branch to interrupt-handler
 pgm_exit:
 	b	BASED(sysc_return)
 
@@ -505,33 +507,34 @@ pgm_per:
 # Normal per exception
 #
 pgm_per_std:
-	SAVE_ALL_SYNC __LC_PGM_OLD_PSW,__LC_SAVE_AREA
-	CREATE_STACK_FRAME __LC_PGM_OLD_PSW,__LC_SAVE_AREA
+	SAVE_ALL_PGM __LC_PGM_OLD_PSW,__LC_SAVE_AREA
+	CREATE_STACK_FRAME __LC_SAVE_AREA
+	mvc	SP_PSW(8,%r15),__LC_PGM_OLD_PSW
+	l	%r12,__LC_THREAD_INFO	# load pointer to thread_info struct
 	tm	SP_PSW+1(%r15),0x01	# interrupting from user ?
 	bz	BASED(pgm_no_vtime2)
 	UPDATE_VTIME __LC_EXIT_TIMER,__LC_SYNC_ENTER_TIMER,__LC_USER_TIMER
 	UPDATE_VTIME __LC_LAST_UPDATE_TIMER,__LC_EXIT_TIMER,__LC_SYSTEM_TIMER
 	mvc	__LC_LAST_UPDATE_TIMER(8),__LC_SYNC_ENTER_TIMER
 pgm_no_vtime2:
-	l	%r9,__LC_THREAD_INFO	# load pointer to thread_info struct
-	l	%r1,__TI_task(%r9)
+	l	%r1,__TI_task(%r12)
 	tm	SP_PSW+1(%r15),0x01	# kernel per event ?
 	bz	BASED(kernel_per)
 	mvc	__THREAD_per+__PER_atmid(2,%r1),__LC_PER_ATMID
 	mvc	__THREAD_per+__PER_address(4,%r1),__LC_PER_ADDRESS
 	mvc	__THREAD_per+__PER_access_id(1,%r1),__LC_PER_ACCESS_ID
-	oi	__TI_flags+3(%r9),_TIF_SINGLE_STEP # set TIF_SINGLE_STEP
+	oi	__TI_flags+3(%r12),_TIF_SINGLE_STEP # set TIF_SINGLE_STEP
 	l	%r3,__LC_PGM_ILC	# load program interruption code
 	l	%r4,__LC_TRANS_EXC_CODE
 	REENABLE_IRQS
 	la	%r8,0x7f
 	nr	%r8,%r3 		# clear per-event-bit and ilc
 	be	BASED(pgm_exit2)	# only per or per+check ?
-	l	%r7,BASED(.Ljump_table)
 	sll	%r8,2
-	l	%r7,0(%r8,%r7)		# load address of handler routine
+	l	%r1,BASED(.Ljump_table)
+	l	%r1,0(%r8,%r1)		# load address of handler routine
 	la	%r2,SP_PTREGS(%r15)	# address of register-save area
-	basr	%r14,%r7		# branch to interrupt-handler
+	basr	%r14,%r1		# branch to interrupt-handler
 pgm_exit2:
 	b	BASED(sysc_return)
 
@@ -539,18 +542,19 @@ pgm_exit2:
 # it was a single stepped SVC that is causing all the trouble
 #
 pgm_svcper:
-	SAVE_ALL_SYNC __LC_SVC_OLD_PSW,__LC_SAVE_AREA
-	CREATE_STACK_FRAME __LC_SVC_OLD_PSW,__LC_SAVE_AREA
+	SAVE_ALL_PGM __LC_SVC_OLD_PSW,__LC_SAVE_AREA
+	CREATE_STACK_FRAME __LC_SAVE_AREA
+	mvc	SP_PSW(8,%r15),__LC_SVC_OLD_PSW
+	mvc	SP_ILC(4,%r15),__LC_SVC_ILC
+	l	%r12,__LC_THREAD_INFO	# load pointer to thread_info struct
 	UPDATE_VTIME __LC_EXIT_TIMER,__LC_SYNC_ENTER_TIMER,__LC_USER_TIMER
 	UPDATE_VTIME __LC_LAST_UPDATE_TIMER,__LC_EXIT_TIMER,__LC_SYSTEM_TIMER
 	mvc	__LC_LAST_UPDATE_TIMER(8),__LC_SYNC_ENTER_TIMER
-	lh	%r7,0x8a		# get svc number from lowcore
-	l	%r9,__LC_THREAD_INFO	# load pointer to thread_info struct
-	l	%r8,__TI_task(%r9)
+	l	%r8,__TI_task(%r12)
 	mvc	__THREAD_per+__PER_atmid(2,%r8),__LC_PER_ATMID
 	mvc	__THREAD_per+__PER_address(4,%r8),__LC_PER_ADDRESS
 	mvc	__THREAD_per+__PER_access_id(1,%r8),__LC_PER_ACCESS_ID
-	oi	__TI_flags+3(%r9),_TIF_SINGLE_STEP # set TIF_SINGLE_STEP
+	oi	__TI_flags+3(%r12),_TIF_SINGLE_STEP # set TIF_SINGLE_STEP
 	stosm	__SF_EMPTY(%r15),0x03	# reenable interrupts
 	lm	%r2,%r6,SP_R2(%r15)	# load svc arguments
 	b	BASED(sysc_do_svc)
@@ -560,8 +564,7 @@ pgm_svcper:
 #
 kernel_per:
 	REENABLE_IRQS
-	mvi	SP_SVCNR(%r15),0xff	# set trap indication to pgm check
-	mvi	SP_SVCNR+1(%r15),0xff
+	xc	SP_SVCNR(2,%r15),SP_SVCNR(%r15)
 	la	%r2,SP_PTREGS(%r15)	# address of register-save area
 	l	%r1,BASED(.Lhandle_per)	# load adr. of per handler
 	basr	%r14,%r1		# branch to do_single_step
@@ -575,9 +578,10 @@ kernel_per:
 io_int_handler:
 	stck	__LC_INT_CLOCK
 	stpt	__LC_ASYNC_ENTER_TIMER
-	SAVE_ALL_BASE __LC_SAVE_AREA+16
 	SAVE_ALL_ASYNC __LC_IO_OLD_PSW,__LC_SAVE_AREA+16
-	CREATE_STACK_FRAME __LC_IO_OLD_PSW,__LC_SAVE_AREA+16
+	CREATE_STACK_FRAME __LC_SAVE_AREA+16
+	mvc	SP_PSW(8,%r15),0(%r12)	# move user PSW to stack
+	l	%r12,__LC_THREAD_INFO	# load pointer to thread_info struct
 	tm	SP_PSW+1(%r15),0x01	# interrupting from user ?
 	bz	BASED(io_no_vtime)
 	UPDATE_VTIME __LC_EXIT_TIMER,__LC_ASYNC_ENTER_TIMER,__LC_USER_TIMER
@@ -585,7 +589,6 @@ io_int_handler:
 	mvc	__LC_LAST_UPDATE_TIMER(8),__LC_ASYNC_ENTER_TIMER
 io_no_vtime:
 	TRACE_IRQS_OFF
-	l	%r9,__LC_THREAD_INFO	# load pointer to thread_info struct
 	l	%r1,BASED(.Ldo_IRQ)	# load address of do_IRQ
 	la	%r2,SP_PTREGS(%r15)	# address of register-save area
 	basr	%r14,%r1		# branch to standard irq handler
@@ -593,7 +596,7 @@ io_return:
 	LOCKDEP_SYS_EXIT
 	TRACE_IRQS_ON
 io_tif:
-	tm	__TI_flags+3(%r9),_TIF_WORK_INT
+	tm	__TI_flags+3(%r12),_TIF_WORK_INT
 	bnz	BASED(io_work)		# there is work to do (signals etc.)
 io_restore:
 	RESTORE_ALL __LC_RETURN_PSW,0
@@ -611,9 +614,9 @@ io_work:
 	bo	BASED(io_work_user)	# yes -> do resched & signal
 #ifdef CONFIG_PREEMPT
 	# check for preemptive scheduling
-	icm	%r0,15,__TI_precount(%r9)
+	icm	%r0,15,__TI_precount(%r12)
 	bnz	BASED(io_restore)	# preemption disabled
-	tm	__TI_flags+3(%r9),_TIF_NEED_RESCHED
+	tm	__TI_flags+3(%r12),_TIF_NEED_RESCHED
 	bno	BASED(io_restore)
 	# switch to kernel stack
 	l	%r1,SP_R15(%r15)
@@ -647,13 +650,13 @@ io_work_user:
 #		and _TIF_MCCK_PENDING
 #
 io_work_tif:
-	tm	__TI_flags+3(%r9),_TIF_MCCK_PENDING
+	tm	__TI_flags+3(%r12),_TIF_MCCK_PENDING
 	bo	BASED(io_mcck_pending)
-	tm	__TI_flags+3(%r9),_TIF_NEED_RESCHED
+	tm	__TI_flags+3(%r12),_TIF_NEED_RESCHED
 	bo	BASED(io_reschedule)
-	tm	__TI_flags+3(%r9),_TIF_SIGPENDING
+	tm	__TI_flags+3(%r12),_TIF_SIGPENDING
 	bo	BASED(io_sigpending)
-	tm	__TI_flags+3(%r9),_TIF_NOTIFY_RESUME
+	tm	__TI_flags+3(%r12),_TIF_NOTIFY_RESUME
 	bo	BASED(io_notify_resume)
 	b	BASED(io_return)	# beware of critical section cleanup
 
@@ -713,16 +716,16 @@ io_notify_resume:
 ext_int_handler:
 	stck	__LC_INT_CLOCK
 	stpt	__LC_ASYNC_ENTER_TIMER
-	SAVE_ALL_BASE __LC_SAVE_AREA+16
 	SAVE_ALL_ASYNC __LC_EXT_OLD_PSW,__LC_SAVE_AREA+16
-	CREATE_STACK_FRAME __LC_EXT_OLD_PSW,__LC_SAVE_AREA+16
+	CREATE_STACK_FRAME __LC_SAVE_AREA+16
+	mvc	SP_PSW(8,%r15),0(%r12)	# move user PSW to stack
+	l	%r12,__LC_THREAD_INFO	# load pointer to thread_info struct
 	tm	SP_PSW+1(%r15),0x01	# interrupting from user ?
 	bz	BASED(ext_no_vtime)
 	UPDATE_VTIME __LC_EXIT_TIMER,__LC_ASYNC_ENTER_TIMER,__LC_USER_TIMER
 	UPDATE_VTIME __LC_LAST_UPDATE_TIMER,__LC_EXIT_TIMER,__LC_SYSTEM_TIMER
 	mvc	__LC_LAST_UPDATE_TIMER(8),__LC_ASYNC_ENTER_TIMER
 ext_no_vtime:
-	l	%r9,__LC_THREAD_INFO	# load pointer to thread_info struct
 	TRACE_IRQS_OFF
 	la	%r2,SP_PTREGS(%r15)	# address of register-save area
 	l	%r3,__LC_CPU_ADDRESS	# get cpu address + interruption code
@@ -777,7 +780,10 @@ mcck_int_main:
 	sra	%r14,PAGE_SHIFT
 	be	BASED(0f)
 	l	%r15,__LC_PANIC_STACK	# load panic stack
-0:	CREATE_STACK_FRAME __LC_MCK_OLD_PSW,__LC_SAVE_AREA+32
+0:	s	%r15,BASED(.Lc_spsize)	# make room for registers & psw
+	CREATE_STACK_FRAME __LC_SAVE_AREA+32
+	mvc	SP_PSW(8,%r15),0(%r12)
+	l	%r12,__LC_THREAD_INFO	# load pointer to thread_info struct
 	tm	__LC_MCCK_CODE+2,0x08	# mwp of old psw valid?
 	bno	BASED(mcck_no_vtime)	# no -> skip cleanup critical
 	tm	SP_PSW+1(%r15),0x01	# interrupting from user ?
@@ -786,7 +792,6 @@ mcck_int_main:
 	UPDATE_VTIME __LC_LAST_UPDATE_TIMER,__LC_EXIT_TIMER,__LC_SYSTEM_TIMER
 	mvc	__LC_LAST_UPDATE_TIMER(8),__LC_MCCK_ENTER_TIMER
 mcck_no_vtime:
-	l	%r9,__LC_THREAD_INFO	# load pointer to thread_info struct
 	la	%r2,SP_PTREGS(%r15)	# load pt_regs
 	l	%r1,BASED(.Ls390_mcck)
 	basr	%r14,%r1		# call machine check handler
@@ -798,7 +803,7 @@ mcck_no_vtime:
 	xc	__SF_BACKCHAIN(4,%r1),__SF_BACKCHAIN(%r1) # clear back chain
 	lr	%r15,%r1
 	stosm	__SF_EMPTY(%r15),0x04	# turn dat on
-	tm	__TI_flags+3(%r9),_TIF_MCCK_PENDING
+	tm	__TI_flags+3(%r12),_TIF_MCCK_PENDING
 	bno	BASED(mcck_return)
 	TRACE_IRQS_OFF
 	l	%r1,BASED(.Ls390_handle_mcck)
@@ -947,12 +952,13 @@ cleanup_system_call:
 	bh	BASED(0f)
 	mvc	__LC_SAVE_AREA(16),0(%r12)
 0:	st	%r13,4(%r12)
-	st	%r12,__LC_SAVE_AREA+48	# argh
-	SAVE_ALL_SYNC __LC_SVC_OLD_PSW,__LC_SAVE_AREA
-	CREATE_STACK_FRAME __LC_SVC_OLD_PSW,__LC_SAVE_AREA
-	l	%r12,__LC_SAVE_AREA+48	# argh
+	l	%r15,__LC_KERNEL_STACK	# problem state -> load ksp
+	s	%r15,BASED(.Lc_spsize)	# make room for registers & psw
 	st	%r15,12(%r12)
-	lh	%r7,0x8a
+	CREATE_STACK_FRAME __LC_SAVE_AREA
+	mvc	SP_PSW(8,%r15),__LC_SVC_OLD_PSW
+	mvc	SP_ILC(4,%r15),__LC_SVC_ILC
+	mvc	0(4,%r12),__LC_THREAD_INFO
 cleanup_vtime:
 	clc	__LC_RETURN_PSW+4(4),BASED(cleanup_system_call_insn+12)
 	bhe	BASED(cleanup_stime)