[PATCH] s390: improved machine check handling

Improved machine check handling.  Kernel is now able to receive machine checks
while in kernel mode (system call, interrupt and program check handling).
Also register validation is now performed.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

arch/s390/kernel/entry.S

@@ -7,6 +7,7 @@
  *    Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
  *               Hartmut Penner (hp@de.ibm.com),
  *               Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com),
+ *		 Heiko Carstens <heiko.carstens@de.ibm.com>
  */
 
 #include <linux/sys.h>
@@ -49,9 +50,9 @@ SP_ILC       =  STACK_FRAME_OVERHEAD + __PT_ILC
 SP_TRAP      =  STACK_FRAME_OVERHEAD + __PT_TRAP
 SP_SIZE      =  STACK_FRAME_OVERHEAD + __PT_SIZE
 
-_TIF_WORK_SVC = (_TIF_SIGPENDING | _TIF_NEED_RESCHED | \
+_TIF_WORK_SVC = (_TIF_SIGPENDING | _TIF_NEED_RESCHED | _TIF_MCCK_PENDING | \
 		 _TIF_RESTART_SVC | _TIF_SINGLE_STEP )
-_TIF_WORK_INT = (_TIF_SIGPENDING | _TIF_NEED_RESCHED)
+_TIF_WORK_INT = (_TIF_SIGPENDING | _TIF_NEED_RESCHED | _TIF_MCCK_PENDING)
 
 STACK_SHIFT = PAGE_SHIFT + THREAD_ORDER
 STACK_SIZE  = 1 << STACK_SHIFT
@@ -121,7 +122,11 @@ STACK_SIZE  = 1 << STACK_SHIFT
 	bz	BASED(stack_overflow)
 3:
 #endif
-2:	s	%r15,BASED(.Lc_spsize)	# make room for registers & psw
+2:
+	.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
 	la	%r12,\psworg
 	st	%r2,SP_ORIG_R2(%r15)	# store original content of gpr 2
@@ -161,6 +166,13 @@ __switch_to_base:
         be      __switch_to_noper-__switch_to_base(%r1)	# we got away w/o bashing TLB's
         lctl    %c9,%c11,__THREAD_per(%r3)	# Nope we didn't
 __switch_to_noper:
+	l	%r4,__THREAD_info(%r2)		# get thread_info of prev
+	tm	__TI_flags+3(%r4),_TIF_MCCK_PENDING # machine check pending?
+	bz	__switch_to_no_mcck-__switch_to_base(%r1)
+	ni	__TI_flags+3(%r4),255-_TIF_MCCK_PENDING # clear flag in prev
+	l	%r4,__THREAD_info(%r3)		# get thread_info of next
+	oi	__TI_flags+3(%r4),_TIF_MCCK_PENDING # set it in next
+__switch_to_no_mcck:
         stm     %r6,%r15,__SF_GPRS(%r15)# store __switch_to registers of prev task
 	st	%r15,__THREAD_ksp(%r2)	# store kernel stack to prev->tss.ksp
 	l	%r15,__THREAD_ksp(%r3)	# load kernel stack from next->tss.ksp
@@ -185,6 +197,7 @@ system_call:
 sysc_saveall:
 	SAVE_ALL_BASE __LC_SAVE_AREA
         SAVE_ALL __LC_SVC_OLD_PSW,__LC_SAVE_AREA,1
+	CREATE_STACK_FRAME __LC_SVC_OLD_PSW,__LC_SAVE_AREA
 	lh	%r7,0x8a	  # get svc number from lowcore
 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
 sysc_vtime:
@@ -234,6 +247,8 @@ sysc_work_loop:
 # One of the work bits is on. Find out which one.
 #
 sysc_work:
+	tm	__TI_flags+3(%r9),_TIF_MCCK_PENDING
+	bo	BASED(sysc_mcck_pending)
 	tm	__TI_flags+3(%r9),_TIF_NEED_RESCHED
 	bo	BASED(sysc_reschedule)
 	tm	__TI_flags+3(%r9),_TIF_SIGPENDING
@@ -252,6 +267,14 @@ sysc_reschedule:
 	la      %r14,BASED(sysc_work_loop)
 	br      %r1		       # call scheduler
 
+#
+# _TIF_MCCK_PENDING is set, call handler
+#
+sysc_mcck_pending:
+	l	%r1,BASED(.Ls390_handle_mcck)
+	la	%r14,BASED(sysc_work_loop)
+	br	%r1			# TIF bit will be cleared by handler
+
 #
 # _TIF_SIGPENDING is set, call do_signal
 #
@@ -430,6 +453,7 @@ pgm_check_handler:
         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 __LC_PGM_OLD_PSW,__LC_SAVE_AREA,1
+	CREATE_STACK_FRAME __LC_PGM_OLD_PSW,__LC_SAVE_AREA
 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
 	tm	SP_PSW+1(%r15),0x01	# interrupting from user ?
 	bz	BASED(pgm_no_vtime)
@@ -468,6 +492,7 @@ pgm_per:
 #
 pgm_per_std:
 	SAVE_ALL __LC_PGM_OLD_PSW,__LC_SAVE_AREA,1
+	CREATE_STACK_FRAME __LC_PGM_OLD_PSW,__LC_SAVE_AREA
 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
 	tm	SP_PSW+1(%r15),0x01	# interrupting from user ?
 	bz	BASED(pgm_no_vtime2)
@@ -493,6 +518,7 @@ pgm_no_vtime2:
 #
 pgm_svcper:
 	SAVE_ALL __LC_SVC_OLD_PSW,__LC_SAVE_AREA,1
+	CREATE_STACK_FRAME __LC_SVC_OLD_PSW,__LC_SAVE_AREA
 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
 	tm	SP_PSW+1(%r15),0x01	# interrupting from user ?
 	bz	BASED(pgm_no_vtime3)
@@ -521,6 +547,7 @@ io_int_handler:
 	stck	__LC_INT_CLOCK
 	SAVE_ALL_BASE __LC_SAVE_AREA+16
         SAVE_ALL __LC_IO_OLD_PSW,__LC_SAVE_AREA+16,0
+	CREATE_STACK_FRAME __LC_IO_OLD_PSW,__LC_SAVE_AREA+16
 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
 	tm	SP_PSW+1(%r15),0x01	# interrupting from user ?
 	bz	BASED(io_no_vtime)
@@ -578,15 +605,25 @@ io_work:
 	lr	%r15,%r1
 #
 # One of the work bits is on. Find out which one.
-# Checked are: _TIF_SIGPENDING and _TIF_NEED_RESCHED
+# Checked are: _TIF_SIGPENDING, _TIF_NEED_RESCHED and _TIF_MCCK_PENDING
 #
 io_work_loop:
+	tm	__TI_flags+3(%r9),_TIF_MCCK_PENDING
+	bo      BASED(io_mcck_pending)
 	tm	__TI_flags+3(%r9),_TIF_NEED_RESCHED
 	bo	BASED(io_reschedule)
 	tm	__TI_flags+3(%r9),_TIF_SIGPENDING
 	bo	BASED(io_sigpending)
 	b	BASED(io_leave)
 
+#
+# _TIF_MCCK_PENDING is set, call handler
+#
+io_mcck_pending:
+	l	%r1,BASED(.Ls390_handle_mcck)
+	l	%r14,BASED(io_work_loop)
+	br	%r1		       # TIF bit will be cleared by handler
+
 #
 # _TIF_NEED_RESCHED is set, call schedule
 #	
@@ -621,6 +658,7 @@ ext_int_handler:
 	stck	__LC_INT_CLOCK
 	SAVE_ALL_BASE __LC_SAVE_AREA+16
         SAVE_ALL __LC_EXT_OLD_PSW,__LC_SAVE_AREA+16,0
+	CREATE_STACK_FRAME __LC_EXT_OLD_PSW,__LC_SAVE_AREA+16
 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
 	tm	SP_PSW+1(%r15),0x01	# interrupting from user ?
 	bz	BASED(ext_no_vtime)
@@ -642,19 +680,62 @@ ext_no_vtime:
 
         .globl mcck_int_handler
 mcck_int_handler:
-	STORE_TIMER __LC_ASYNC_ENTER_TIMER
+	spt	__LC_CPU_TIMER_SAVE_AREA	# revalidate cpu timer
+	lm	%r0,%r15,__LC_GPREGS_SAVE_AREA	# revalidate gprs
 	SAVE_ALL_BASE __LC_SAVE_AREA+32
-        SAVE_ALL __LC_MCK_OLD_PSW,__LC_SAVE_AREA+32,0
+	la	%r12,__LC_MCK_OLD_PSW
+	tm	__LC_MCCK_CODE,0x80     # system damage?
+	bo	BASED(mcck_int_main)	# yes -> rest of mcck code invalid
+	tm	__LC_MCCK_CODE+5,0x02   # stored cpu timer value valid?
+	bo	BASED(0f)
+	spt	__LC_LAST_UPDATE_TIMER	# revalidate cpu timer
 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
-	tm	SP_PSW+1(%r15),0x01	# interrupting from user ?
+	mvc	__LC_LAST_UPDATE_TIMER(8),__LC_ASYNC_ENTER_TIMER
+	mvc	__LC_LAST_UPDATE_TIMER(8),__LC_SYNC_ENTER_TIMER
+	mvc	__LC_LAST_UPDATE_TIMER(8),__LC_EXIT_TIMER
+0:	tm	__LC_MCCK_CODE+2,0x08   # mwp of old psw valid?
+	bno	BASED(mcck_no_vtime)	# no -> skip cleanup critical
+	tm	__LC_MCK_OLD_PSW+1,0x01 # interrupting from user ?
 	bz	BASED(mcck_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
 mcck_no_vtime:
 #endif
+0:
+	tm	__LC_MCCK_CODE+2,0x09   # mwp + ia of old psw valid?
+	bno	BASED(mcck_int_main)	# no -> skip cleanup critical
+	tm	__LC_MCK_OLD_PSW+1,0x01	# test problem state bit
+	bnz	BASED(mcck_int_main)	# from user -> load async stack
+	clc	__LC_MCK_OLD_PSW+4(4),BASED(.Lcritical_end)
+	bhe	BASED(mcck_int_main)
+	clc	__LC_MCK_OLD_PSW+4(4),BASED(.Lcritical_start)
+	bl	BASED(mcck_int_main)
+	l	%r14,BASED(.Lcleanup_critical)
+	basr	%r14,%r14
+mcck_int_main:
+	l	%r14,__LC_PANIC_STACK	# are we already on the panic stack?
+	slr	%r14,%r15
+	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
+	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
+	tm      SP_PSW+1(%r15),0x01	# returning to user ?
+	bno	BASED(mcck_return)
+	l	%r1,__LC_KERNEL_STACK   # switch to kernel stack
+	s	%r1,BASED(.Lc_spsize)
+	mvc	SP_PTREGS(__PT_SIZE,%r1),SP_PTREGS(%r15)
+	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
+	bno	BASED(mcck_return)
+	l	%r1,BASED(.Ls390_handle_mcck)
+	basr	%r14,%r1		# call machine check handler
 mcck_return:
         RESTORE_ALL 0
 
@@ -742,7 +823,7 @@ cleanup_critical:
 	clc	4(4,%r12),BASED(cleanup_table_sysc_work_loop)
 	bl	BASED(0f)
 	clc	4(4,%r12),BASED(cleanup_table_sysc_work_loop+4)
-	bl	BASED(cleanup_sysc_leave)
+	bl	BASED(cleanup_sysc_return)
 0:
 	br	%r14
 
@@ -760,6 +841,7 @@ cleanup_system_call:
 	mvc	__LC_SAVE_AREA(16),__LC_SAVE_AREA+16
 0:	st	%r13,__LC_SAVE_AREA+20
 	SAVE_ALL __LC_SVC_OLD_PSW,__LC_SAVE_AREA,1
+	CREATE_STACK_FRAME __LC_SVC_OLD_PSW,__LC_SAVE_AREA
 	st	%r15,__LC_SAVE_AREA+28
 	lh	%r7,0x8a
 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
@@ -834,6 +916,8 @@ cleanup_sysc_leave_insn:
  * Symbol constants
  */
 .Ls390_mcck:   .long  s390_do_machine_check
+.Ls390_handle_mcck:
+	       .long  s390_handle_mcck
 .Ldo_IRQ:      .long  do_IRQ
 .Ldo_extint:   .long  do_extint
 .Ldo_signal:   .long  do_signal

arch/s390/kernel/entry64.S

@@ -7,6 +7,7 @@
  *    Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
  *               Hartmut Penner (hp@de.ibm.com),
  *               Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com),
+ *		 Heiko Carstens <heiko.carstens@de.ibm.com>
  */
 
 #include <linux/sys.h>
@@ -52,9 +53,9 @@ SP_SIZE      =  STACK_FRAME_OVERHEAD + __PT_SIZE
 STACK_SHIFT = PAGE_SHIFT + THREAD_ORDER
 STACK_SIZE  = 1 << STACK_SHIFT
 
-_TIF_WORK_SVC = (_TIF_SIGPENDING | _TIF_NEED_RESCHED | \
+_TIF_WORK_SVC = (_TIF_SIGPENDING | _TIF_NEED_RESCHED | _TIF_MCCK_PENDING | \
 		 _TIF_RESTART_SVC | _TIF_SINGLE_STEP )
-_TIF_WORK_INT = (_TIF_SIGPENDING | _TIF_NEED_RESCHED)
+_TIF_WORK_INT = (_TIF_SIGPENDING | _TIF_NEED_RESCHED | _TIF_MCCK_PENDING)
 
 #define BASED(name) name-system_call(%r13)
 
@@ -114,7 +115,11 @@ _TIF_WORK_INT = (_TIF_SIGPENDING | _TIF_NEED_RESCHED)
 	jz	stack_overflow
 3:
 #endif
-2:	aghi    %r15,-SP_SIZE		# make room for registers & psw
+2:
+	.endm
+
+	.macro	CREATE_STACK_FRAME psworg,savearea
+	aghi    %r15,-SP_SIZE		# make room for registers & psw
 	mvc     SP_PSW(16,%r15),0(%r12)	# move user PSW to stack
 	la	%r12,\psworg
 	stg	%r2,SP_ORIG_R2(%r15)	# store original content of gpr 2
@@ -152,6 +157,13 @@ __switch_to:
         je      __switch_to_noper            # we got away without bashing TLB's
         lctlg   %c9,%c11,__THREAD_per(%r3)	# Nope we didn't
 __switch_to_noper:
+	lg	%r4,__THREAD_info(%r2)              # get thread_info of prev
+	tm	__TI_flags+7(%r4),_TIF_MCCK_PENDING # machine check pending?
+	jz	__switch_to_no_mcck
+	ni	__TI_flags+7(%r4),255-_TIF_MCCK_PENDING # clear flag in prev
+	lg	%r4,__THREAD_info(%r3)		    # get thread_info of next
+	oi	__TI_flags+7(%r4),_TIF_MCCK_PENDING # set it in next
+__switch_to_no_mcck:
         stmg    %r6,%r15,__SF_GPRS(%r15)# store __switch_to registers of prev task
 	stg	%r15,__THREAD_ksp(%r2)	# store kernel stack to prev->tss.ksp
 	lg	%r15,__THREAD_ksp(%r3)	# load kernel stack from next->tss.ksp
@@ -176,6 +188,7 @@ system_call:
 sysc_saveall:
 	SAVE_ALL_BASE __LC_SAVE_AREA
         SAVE_ALL __LC_SVC_OLD_PSW,__LC_SAVE_AREA,1
+        CREATE_STACK_FRAME __LC_SVC_OLD_PSW,__LC_SAVE_AREA
 	llgh    %r7,__LC_SVC_INT_CODE # get svc number from lowcore
 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
 sysc_vtime:
@@ -232,6 +245,8 @@ sysc_work_loop:
 # One of the work bits is on. Find out which one.
 #
 sysc_work:
+	tm	__TI_flags+7(%r9),_TIF_MCCK_PENDING
+	jo	sysc_mcck_pending
 	tm	__TI_flags+7(%r9),_TIF_NEED_RESCHED
 	jo	sysc_reschedule
 	tm	__TI_flags+7(%r9),_TIF_SIGPENDING
@@ -249,6 +264,13 @@ sysc_reschedule:
 	larl    %r14,sysc_work_loop
         jg      schedule            # return point is sysc_return
 
+#
+# _TIF_MCCK_PENDING is set, call handler
+#
+sysc_mcck_pending:
+	larl	%r14,sysc_work_loop
+	jg	s390_handle_mcck    # TIF bit will be cleared by handler
+
 #
 # _TIF_SIGPENDING is set, call do_signal
 #
@@ -474,6 +496,7 @@ pgm_check_handler:
         tm      __LC_PGM_INT_CODE+1,0x80 # check whether we got a per exception
         jnz     pgm_per                  # got per exception -> special case
 	SAVE_ALL __LC_PGM_OLD_PSW,__LC_SAVE_AREA,1
+	CREATE_STACK_FRAME __LC_PGM_OLD_PSW,__LC_SAVE_AREA
 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
 	tm	SP_PSW+1(%r15),0x01	# interrupting from user ?
 	jz	pgm_no_vtime
@@ -512,6 +535,7 @@ pgm_per:
 #
 pgm_per_std:
 	SAVE_ALL __LC_PGM_OLD_PSW,__LC_SAVE_AREA,1
+	CREATE_STACK_FRAME __LC_PGM_OLD_PSW,__LC_SAVE_AREA
 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
 	tm	SP_PSW+1(%r15),0x01	# interrupting from user ?
 	jz	pgm_no_vtime2
@@ -537,6 +561,7 @@ pgm_no_vtime2:
 #
 pgm_svcper:
 	SAVE_ALL __LC_SVC_OLD_PSW,__LC_SAVE_AREA,1
+	CREATE_STACK_FRAME __LC_SVC_OLD_PSW,__LC_SAVE_AREA
 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
 	tm	SP_PSW+1(%r15),0x01	# interrupting from user ?
 	jz	pgm_no_vtime3
@@ -564,6 +589,7 @@ io_int_handler:
 	stck	__LC_INT_CLOCK
 	SAVE_ALL_BASE __LC_SAVE_AREA+32
         SAVE_ALL __LC_IO_OLD_PSW,__LC_SAVE_AREA+32,0
+	CREATE_STACK_FRAME __LC_IO_OLD_PSW,__LC_SAVE_AREA+32
 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
 	tm	SP_PSW+1(%r15),0x01	# interrupting from user ?
 	jz	io_no_vtime
@@ -621,15 +647,24 @@ io_work:
 	lgr	%r15,%r1
 #
 # One of the work bits is on. Find out which one.
-# Checked are: _TIF_SIGPENDING and _TIF_NEED_RESCHED
+# Checked are: _TIF_SIGPENDING, _TIF_NEED_RESCHED and _TIF_MCCK_PENDING
 #
 io_work_loop:
+	tm	__TI_flags+7(%r9),_TIF_MCCK_PENDING
+	jo	io_mcck_pending
 	tm	__TI_flags+7(%r9),_TIF_NEED_RESCHED
 	jo	io_reschedule
 	tm	__TI_flags+7(%r9),_TIF_SIGPENDING
 	jo	io_sigpending
 	j	io_leave
 
+#
+# _TIF_MCCK_PENDING is set, call handler
+#
+io_mcck_pending:
+	larl	%r14,io_work_loop
+	jg	s390_handle_mcck	# TIF bit will be cleared by handler
+
 #
 # _TIF_NEED_RESCHED is set, call schedule
 #	
@@ -661,6 +696,7 @@ ext_int_handler:
 	stck	__LC_INT_CLOCK
 	SAVE_ALL_BASE __LC_SAVE_AREA+32
         SAVE_ALL __LC_EXT_OLD_PSW,__LC_SAVE_AREA+32,0
+	CREATE_STACK_FRAME __LC_EXT_OLD_PSW,__LC_SAVE_AREA+32
 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
 	tm	SP_PSW+1(%r15),0x01	# interrupting from user ?
 	jz	ext_no_vtime
@@ -680,18 +716,60 @@ ext_no_vtime:
  */
         .globl mcck_int_handler
 mcck_int_handler:
-	STORE_TIMER __LC_ASYNC_ENTER_TIMER
+	la	%r1,4095		# revalidate r1
+	spt	__LC_CPU_TIMER_SAVE_AREA-4095(%r1)	# revalidate cpu timer
+  	lmg     %r0,%r15,__LC_GPREGS_SAVE_AREA-4095(%r1)# revalidate gprs
 	SAVE_ALL_BASE __LC_SAVE_AREA+64
-        SAVE_ALL __LC_MCK_OLD_PSW,__LC_SAVE_AREA+64,0
+	la	%r12,__LC_MCK_OLD_PSW
+	tm	__LC_MCCK_CODE,0x80     # system damage?
+	jo	mcck_int_main		# yes -> rest of mcck code invalid
+	tm	__LC_MCCK_CODE+5,0x02   # stored cpu timer value valid?
+	jo	0f
+	spt	__LC_LAST_UPDATE_TIMER
 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
-	tm	SP_PSW+1(%r15),0x01	# interrupting from user ?
+	mvc	__LC_LAST_UPDATE_TIMER(8),__LC_ASYNC_ENTER_TIMER
+	mvc	__LC_LAST_UPDATE_TIMER(8),__LC_SYNC_ENTER_TIMER
+	mvc	__LC_LAST_UPDATE_TIMER(8),__LC_EXIT_TIMER
+0:	tm	__LC_MCCK_CODE+2,0x08	# mwp of old psw valid?
+	jno	mcck_no_vtime		# no -> no timer update
+	tm      __LC_MCK_OLD_PSW+1,0x01 # interrupting from user ?
 	jz	mcck_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
 mcck_no_vtime:
 #endif
+0:
+	tm	__LC_MCCK_CODE+2,0x09   # mwp + ia of old psw valid?
+	jno	mcck_int_main		# no -> skip cleanup critical
+	tm      __LC_MCK_OLD_PSW+1,0x01 # test problem state bit
+	jnz	mcck_int_main		# from user -> load kernel stack
+	clc	__LC_MCK_OLD_PSW+8(8),BASED(.Lcritical_end)
+	jhe	mcck_int_main
+	clc     __LC_MCK_OLD_PSW+8(8),BASED(.Lcritical_start)
+	jl	mcck_int_main
+	brasl   %r14,cleanup_critical
+mcck_int_main:
+	lg      %r14,__LC_PANIC_STACK   # are we already on the panic stack?
+	slgr	%r14,%r15
+	srag	%r14,%r14,PAGE_SHIFT
+	jz	0f
+	lg      %r15,__LC_PANIC_STACK   # load panic stack
+0:	CREATE_STACK_FRAME __LC_MCK_OLD_PSW,__LC_SAVE_AREA+64
+	lg	%r9,__LC_THREAD_INFO	# load pointer to thread_info struct
+	la	%r2,SP_PTREGS(%r15)	# load pt_regs
 	brasl	%r14,s390_do_machine_check
+	tm	SP_PSW+1(%r15),0x01     # returning to user ?
+	jno	mcck_return
+	lg	%r1,__LC_KERNEL_STACK	# switch to kernel stack
+	aghi	%r1,-SP_SIZE
+	mvc	SP_PTREGS(__PT_SIZE,%r1),SP_PTREGS(%r15)
+	xc	__SF_BACKCHAIN(8,%r1),__SF_BACKCHAIN(%r1) # clear back chain
+	lgr	%r15,%r1
+	stosm	__SF_EMPTY(%r15),0x04	# turn dat on
+	tm	__TI_flags+7(%r9),_TIF_MCCK_PENDING
+	jno	mcck_return
+	brasl	%r14,s390_handle_mcck
 mcck_return:
         RESTORE_ALL 0
 
@@ -775,7 +853,7 @@ cleanup_critical:
 	clc	8(8,%r12),BASED(cleanup_table_sysc_work_loop)
 	jl	0f
 	clc	8(8,%r12),BASED(cleanup_table_sysc_work_loop+8)
-	jl	cleanup_sysc_leave
+	jl	cleanup_sysc_return
 0:
 	br	%r14
 
@@ -793,6 +871,7 @@ cleanup_system_call:
 	mvc	__LC_SAVE_AREA(32),__LC_SAVE_AREA+32
 0:	stg	%r13,__LC_SAVE_AREA+40
 	SAVE_ALL __LC_SVC_OLD_PSW,__LC_SAVE_AREA,1
+	CREATE_STACK_FRAME __LC_SVC_OLD_PSW,__LC_SAVE_AREA
 	stg	%r15,__LC_SAVE_AREA+56
 	llgh	%r7,__LC_SVC_INT_CODE
 #ifdef CONFIG_VIRT_CPU_ACCOUNTING

arch/s390/kernel/process.c

@@ -91,13 +91,12 @@ void do_monitor_call(struct pt_regs *regs, long interruption_code)
 			    (void *)(long) smp_processor_id());
 }
 
+extern void s390_handle_mcck(void);
 /*
  * The idle loop on a S390...
  */
 void default_idle(void)
 {
-	psw_t wait_psw;
-	unsigned long reg;
 	int cpu, rc;
 
 	local_irq_disable();
@@ -125,38 +124,17 @@ void default_idle(void)
 		cpu_die();
 #endif
 
-	/* 
-	 * Wait for external, I/O or machine check interrupt and
-	 * switch off machine check bit after the wait has ended.
-	 */
-	wait_psw.mask = PSW_KERNEL_BITS | PSW_MASK_MCHECK | PSW_MASK_WAIT |
-		PSW_MASK_IO | PSW_MASK_EXT;
-#ifndef CONFIG_ARCH_S390X
-	asm volatile (
-		"    basr %0,0\n"
-		"0:  la   %0,1f-0b(%0)\n"
-		"    st   %0,4(%1)\n"
-		"    oi   4(%1),0x80\n"
-		"    lpsw 0(%1)\n"
-		"1:  la   %0,2f-1b(%0)\n"
-		"    st   %0,4(%1)\n"
-		"    oi   4(%1),0x80\n"
-		"    ni   1(%1),0xf9\n"
-		"    lpsw 0(%1)\n"
-		"2:"
-		: "=&a" (reg) : "a" (&wait_psw) : "memory", "cc" );
-#else /* CONFIG_ARCH_S390X */
-	asm volatile (
-		"    larl  %0,0f\n"
-		"    stg   %0,8(%1)\n"
-		"    lpswe 0(%1)\n"
-		"0:  larl  %0,1f\n"
-		"    stg   %0,8(%1)\n"
-		"    ni    1(%1),0xf9\n"
-		"    lpswe 0(%1)\n"
-		"1:"
-		: "=&a" (reg) : "a" (&wait_psw) : "memory", "cc" );
-#endif /* CONFIG_ARCH_S390X */
+	local_mcck_disable();
+	if (test_thread_flag(TIF_MCCK_PENDING)) {
+		local_mcck_enable();
+		local_irq_enable();
+		s390_handle_mcck();
+		return;
+	}
+
+	/* Wait for external, I/O or machine check interrupt. */
+	__load_psw_mask(PSW_KERNEL_BITS | PSW_MASK_WAIT |
+			PSW_MASK_IO | PSW_MASK_EXT);
 }
 
 void cpu_idle(void)

arch/s390/kernel/setup.c

@@ -414,7 +414,8 @@ setup_lowcore(void)
 	lc->program_new_psw.mask = PSW_KERNEL_BITS;
 	lc->program_new_psw.addr =
 		PSW_ADDR_AMODE | (unsigned long)pgm_check_handler;
-	lc->mcck_new_psw.mask = PSW_KERNEL_BITS;
+	lc->mcck_new_psw.mask =
+		PSW_KERNEL_BITS & ~PSW_MASK_MCHECK & ~PSW_MASK_DAT;
 	lc->mcck_new_psw.addr =
 		PSW_ADDR_AMODE | (unsigned long) mcck_int_handler;
 	lc->io_new_psw.mask = PSW_KERNEL_BITS;
@@ -424,12 +425,18 @@ setup_lowcore(void)
 	lc->kernel_stack = ((unsigned long) &init_thread_union) + THREAD_SIZE;
 	lc->async_stack = (unsigned long)
 		__alloc_bootmem(ASYNC_SIZE, ASYNC_SIZE, 0) + ASYNC_SIZE;
-#ifdef CONFIG_CHECK_STACK
 	lc->panic_stack = (unsigned long)
 		__alloc_bootmem(PAGE_SIZE, PAGE_SIZE, 0) + PAGE_SIZE;
-#endif
 	lc->current_task = (unsigned long) init_thread_union.thread_info.task;
 	lc->thread_info = (unsigned long) &init_thread_union;
+#ifndef CONFIG_ARCH_S390X
+	if (MACHINE_HAS_IEEE) {
+		lc->extended_save_area_addr = (__u32)
+			__alloc_bootmem(PAGE_SIZE, PAGE_SIZE, 0);
+		/* enable extended save area */
+		ctl_set_bit(14, 29);
+	}
+#endif
 #ifdef CONFIG_ARCH_S390X
 	if (MACHINE_HAS_DIAG44)
 		lc->diag44_opcode = 0x83000044;

arch/s390/kernel/smp.c

@@ -773,13 +773,24 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
 
 		*(lowcore_ptr[i]) = S390_lowcore;
 		lowcore_ptr[i]->async_stack = stack + (ASYNC_SIZE);
-#ifdef CONFIG_CHECK_STACK
 		stack = __get_free_pages(GFP_KERNEL,0);
 		if (stack == 0ULL)
 			panic("smp_boot_cpus failed to allocate memory\n");
 		lowcore_ptr[i]->panic_stack = stack + (PAGE_SIZE);
+#ifndef __s390x__
+		if (MACHINE_HAS_IEEE) {
+			lowcore_ptr[i]->extended_save_area_addr =
+				(__u32) __get_free_pages(GFP_KERNEL,0);
+			if (lowcore_ptr[i]->extended_save_area_addr == 0)
+				panic("smp_boot_cpus failed to "
+				      "allocate memory\n");
+		}
 #endif
 	}
+#ifndef __s390x__
+	if (MACHINE_HAS_IEEE)
+		ctl_set_bit(14, 29); /* enable extended save area */
+#endif
 	set_prefix((u32)(unsigned long) lowcore_ptr[smp_processor_id()]);
 
 	for_each_cpu(cpu)

drivers/s390/s390mach.c

@@ -31,14 +31,14 @@ extern void css_reiterate_subchannels(void);
 extern struct workqueue_struct *slow_path_wq;
 extern struct work_struct slow_path_work;
 
-static void
+static NORET_TYPE void
 s390_handle_damage(char *msg)
 {
-	printk(KERN_EMERG "%s\n", msg);
 #ifdef CONFIG_SMP
 	smp_send_stop();
 #endif
 	disabled_wait((unsigned long) __builtin_return_address(0));
+	for(;;);
 }
 
 /*
@@ -122,40 +122,39 @@ s390_collect_crw_info(void *param)
 	return 0;
 }
 
+struct mcck_struct {
+	int kill_task;
+	int channel_report;
+	int warning;
+	unsigned long long mcck_code;
+};
+
+static DEFINE_PER_CPU(struct mcck_struct, cpu_mcck);
+
 /*
- * machine check handler.
+ * Main machine check handler function. Will be called with interrupts enabled
+ * or disabled and machine checks enabled or disabled.
  */
 void
-s390_do_machine_check(void)
+s390_handle_mcck(void)
 {
-	struct mci *mci;
-
-	mci = (struct mci *) &S390_lowcore.mcck_interruption_code;
-
-	if (mci->sd)		/* system damage */
-		s390_handle_damage("received system damage machine check\n");
-
-	if (mci->pd)		/* instruction processing damage */
-		s390_handle_damage("received instruction processing "
-				   "damage machine check\n");
-
-	if (mci->se)		/* storage error uncorrected */
-		s390_handle_damage("received storage error uncorrected "
-				   "machine check\n");
-
-	if (mci->sc)		/* storage error corrected */
-		printk(KERN_WARNING
-		       "received storage error corrected machine check\n");
+	unsigned long flags;
+	struct mcck_struct mcck;
 
-	if (mci->ke)		/* storage key-error uncorrected */
-		s390_handle_damage("received storage key-error uncorrected "
-				   "machine check\n");
-
-	if (mci->ds && mci->fa)	/* storage degradation */
-		s390_handle_damage("received storage degradation machine "
-				   "check\n");
+	/*
+	 * Disable machine checks and get the current state of accumulated
+	 * machine checks. Afterwards delete the old state and enable machine
+	 * checks again.
+	 */
+	local_irq_save(flags);
+	local_mcck_disable();
+	mcck = __get_cpu_var(cpu_mcck);
+	memset(&__get_cpu_var(cpu_mcck), 0, sizeof(struct mcck_struct));
+	clear_thread_flag(TIF_MCCK_PENDING);
+	local_mcck_enable();
+	local_irq_restore(flags);
 
-	if (mci->cp)		/* channel report word pending */
+	if (mcck.channel_report)
 		up(&m_sem);
 
 #ifdef CONFIG_MACHCHK_WARNING
@@ -168,7 +167,7 @@ s390_do_machine_check(void)
  * On VM we only get one interrupt per virtally presented machinecheck.
  * Though one suffices, we may get one interrupt per (virtual) processor.
  */
-	if (mci->w) {	/* WARNING pending ? */
+	if (mcck.warning) {	/* WARNING pending ? */
 		static int mchchk_wng_posted = 0;
 		/*
 		 * Use single machine clear, as we cannot handle smp right now
@@ -178,6 +177,261 @@ s390_do_machine_check(void)
 			kill_proc(1, SIGPWR, 1);
 	}
 #endif
+
+	if (mcck.kill_task) {
+		local_irq_enable();
+		printk(KERN_EMERG "mcck: Terminating task because of machine "
+		       "malfunction (code 0x%016llx).\n", mcck.mcck_code);
+		printk(KERN_EMERG "mcck: task: %s, pid: %d.\n",
+		       current->comm, current->pid);
+		do_exit(SIGSEGV);
+	}
+}
+
+/*
+ * returns 0 if all registers could be validated
+ * returns 1 otherwise
+ */
+static int
+s390_revalidate_registers(struct mci *mci)
+{
+	int kill_task;
+	u64 tmpclock;
+	u64 zero;
+	void *fpt_save_area, *fpt_creg_save_area;
+
+	kill_task = 0;
+	zero = 0;
+	/* General purpose registers */
+	if (!mci->gr)
+		/*
+		 * General purpose registers couldn't be restored and have
+		 * unknown contents. Process needs to be terminated.
+		 */
+		kill_task = 1;
+
+	/* Revalidate floating point registers */
+	if (!mci->fp)
+		/*
+		 * Floating point registers can't be restored and
+		 * therefore the process needs to be terminated.
+		 */
+		kill_task = 1;
+
+#ifndef __s390x__
+	asm volatile("ld 0,0(%0)\n"
+		     "ld 2,8(%0)\n"
+		     "ld 4,16(%0)\n"
+		     "ld 6,24(%0)"
+		     : : "a" (&S390_lowcore.floating_pt_save_area));
+#endif
+
+	if (MACHINE_HAS_IEEE) {
+#ifdef __s390x__
+		fpt_save_area = &S390_lowcore.floating_pt_save_area;
+		fpt_creg_save_area = &S390_lowcore.fpt_creg_save_area;
+#else
+		fpt_save_area = (void *) S390_lowcore.extended_save_area_addr;
+		fpt_creg_save_area = fpt_save_area+128;
+#endif
+		/* Floating point control register */
+		if (!mci->fc) {
+			/*
+			 * Floating point control register can't be restored.
+			 * Task will be terminated.
+			 */
+			asm volatile ("lfpc 0(%0)" : : "a" (&zero));
+			kill_task = 1;
+
+		}
+		else
+			asm volatile (
+				"lfpc 0(%0)"
+				: : "a" (fpt_creg_save_area));
+
+		asm volatile("ld  0,0(%0)\n"
+			     "ld  1,8(%0)\n"
+			     "ld  2,16(%0)\n"
+			     "ld  3,24(%0)\n"
+			     "ld  4,32(%0)\n"
+			     "ld  5,40(%0)\n"
+			     "ld  6,48(%0)\n"
+			     "ld  7,56(%0)\n"
+			     "ld  8,64(%0)\n"
+			     "ld  9,72(%0)\n"
+			     "ld 10,80(%0)\n"
+			     "ld 11,88(%0)\n"
+			     "ld 12,96(%0)\n"
+			     "ld 13,104(%0)\n"
+			     "ld 14,112(%0)\n"
+			     "ld 15,120(%0)\n"
+			     : : "a" (fpt_save_area));
+	}
+
+	/* Revalidate access registers */
+	asm volatile("lam 0,15,0(%0)"
+		     : : "a" (&S390_lowcore.access_regs_save_area));
+	if (!mci->ar)
+		/*
+		 * Access registers have unknown contents.
+		 * Terminating task.
+		 */
+		kill_task = 1;
+
+	/* Revalidate control registers */
+	if (!mci->cr)
+		/*
+		 * Control registers have unknown contents.
+		 * Can't recover and therefore stopping machine.
+		 */
+		s390_handle_damage("invalid control registers.");
+	else
+#ifdef __s390x__
+		asm volatile("lctlg 0,15,0(%0)"
+			     : : "a" (&S390_lowcore.cregs_save_area));
+#else
+		asm volatile("lctl 0,15,0(%0)"
+			     : : "a" (&S390_lowcore.cregs_save_area));
+#endif
+
+	/*
+	 * We don't even try to revalidate the TOD register, since we simply
+	 * can't write something sensible into that register.
+	 */
+
+#ifdef __s390x__
+	/*
+	 * See if we can revalidate the TOD programmable register with its
+	 * old contents (should be zero) otherwise set it to zero.
+	 */
+	if (!mci->pr)
+		asm volatile("sr 0,0\n"
+			     "sckpf"
+			     : : : "0", "cc");
+	else
+		asm volatile(
+			"l 0,0(%0)\n"
+			"sckpf"
+			: : "a" (&S390_lowcore.tod_progreg_save_area) : "0", "cc");
+#endif
+
+	/* Revalidate clock comparator register */
+	asm volatile ("stck 0(%1)\n"
+		      "sckc 0(%1)"
+		      : "=m" (tmpclock) : "a" (&(tmpclock)) : "cc", "memory");
+
+	/* Check if old PSW is valid */
+	if (!mci->wp)
+		/*
+		 * Can't tell if we come from user or kernel mode
+		 * -> stopping machine.
+		 */
+		s390_handle_damage("old psw invalid.");
+
+	if (!mci->ms || !mci->pm || !mci->ia)
+		kill_task = 1;
+
+	return kill_task;
+}
+
+/*
+ * machine check handler.
+ */
+void
+s390_do_machine_check(struct pt_regs *regs)
+{
+	struct mci *mci;
+	struct mcck_struct *mcck;
+	int umode;
+
+	mci = (struct mci *) &S390_lowcore.mcck_interruption_code;
+	mcck = &__get_cpu_var(cpu_mcck);
+	umode = user_mode(regs);
+
+	if (mci->sd)
+		/* System damage -> stopping machine */
+		s390_handle_damage("received system damage machine check.");
+
+	if (mci->pd) {
+		if (mci->b) {
+			/* Processing backup -> verify if we can survive this */
+			u64 z_mcic, o_mcic, t_mcic;
+#ifdef __s390x__
+			z_mcic = (1ULL<<63 | 1ULL<<59 | 1ULL<<29);
+			o_mcic = (1ULL<<43 | 1ULL<<42 | 1ULL<<41 | 1ULL<<40 |
+				  1ULL<<36 | 1ULL<<35 | 1ULL<<34 | 1ULL<<32 |
+				  1ULL<<30 | 1ULL<<21 | 1ULL<<20 | 1ULL<<17 |
+				  1ULL<<16);
+#else
+			z_mcic = (1ULL<<63 | 1ULL<<59 | 1ULL<<57 | 1ULL<<50 |
+				  1ULL<<29);
+			o_mcic = (1ULL<<43 | 1ULL<<42 | 1ULL<<41 | 1ULL<<40 |
+				  1ULL<<36 | 1ULL<<35 | 1ULL<<34 | 1ULL<<32 |
+				  1ULL<<30 | 1ULL<<20 | 1ULL<<17 | 1ULL<<16);
+#endif
+			t_mcic = *(u64 *)mci;
+
+			if (((t_mcic & z_mcic) != 0) ||
+			    ((t_mcic & o_mcic) != o_mcic)) {
+				s390_handle_damage("processing backup machine "
+						   "check with damage.");
+			}
+			if (!umode)
+				s390_handle_damage("processing backup machine "
+						   "check in kernel mode.");
+			mcck->kill_task = 1;
+			mcck->mcck_code = *(unsigned long long *) mci;
+		}
+		else {
+			/* Processing damage -> stopping machine */
+			s390_handle_damage("received instruction processing "
+					   "damage machine check.");
+		}
+	}
+	if (s390_revalidate_registers(mci)) {
+		if (umode) {
+			/*
+			 * Couldn't restore all register contents while in
+			 * user mode -> mark task for termination.
+			 */
+			mcck->kill_task = 1;
+			mcck->mcck_code = *(unsigned long long *) mci;
+			set_thread_flag(TIF_MCCK_PENDING);
+		}
+		else
+			/*
+			 * Couldn't restore all register contents while in
+			 * kernel mode -> stopping machine.
+			 */
+			s390_handle_damage("unable to revalidate registers.");
+	}
+
+	if (mci->se)
+		/* Storage error uncorrected */
+		s390_handle_damage("received storage error uncorrected "
+				   "machine check.");
+
+	if (mci->ke)
+		/* Storage key-error uncorrected */
+		s390_handle_damage("received storage key-error uncorrected "
+				   "machine check.");
+
+	if (mci->ds && mci->fa)
+		/* Storage degradation */
+		s390_handle_damage("received storage degradation machine "
+				   "check.");
+
+	if (mci->cp) {
+		/* Channel report word pending */
+		mcck->channel_report = 1;
+		set_thread_flag(TIF_MCCK_PENDING);
+	}
+
+	if (mci->w) {
+		/* Warning pending */
+		mcck->warning = 1;
+		set_thread_flag(TIF_MCCK_PENDING);
+	}
 }
 
 /*
@@ -189,8 +443,7 @@ static int
 machine_check_init(void)
 {
 	init_MUTEX_LOCKED(&m_sem);
-	ctl_clear_bit(14, 25);	/* disable damage MCH */
-	ctl_set_bit(14, 26);	/* enable degradation MCH */
+	ctl_clear_bit(14, 25);	/* disable external damage MCH */
 	ctl_set_bit(14, 27);    /* enable system recovery MCH */
 #ifdef CONFIG_MACHCHK_WARNING
 	ctl_set_bit(14, 24);	/* enable warning MCH */

drivers/s390/s390mach.h

@@ -16,20 +16,45 @@ struct mci {
 	__u32   sd              :  1; /* 00 system damage */
 	__u32   pd              :  1; /* 01 instruction-processing damage */
 	__u32   sr              :  1; /* 02 system recovery */
-	__u32   to_be_defined_1 :  4; /* 03-06 */
+	__u32   to_be_defined_1 :  1; /* 03 */
+	__u32   cd              :  1; /* 04 timing-facility damage */
+	__u32   ed              :  1; /* 05 external damage */
+	__u32   to_be_defined_2 :  1; /* 06 */
 	__u32   dg              :  1; /* 07 degradation */
 	__u32   w               :  1; /* 08 warning pending */
 	__u32   cp              :  1; /* 09 channel-report pending */
-	__u32   to_be_defined_2 :  6; /* 10-15 */
+	__u32   sp              :  1; /* 10 service-processor damage */
+	__u32   ck              :  1; /* 11 channel-subsystem damage */
+	__u32   to_be_defined_3 :  2; /* 12-13 */
+	__u32   b               :  1; /* 14 backed up */
+	__u32   to_be_defined_4 :  1; /* 15 */
 	__u32   se              :  1; /* 16 storage error uncorrected */
 	__u32   sc              :  1; /* 17 storage error corrected */
 	__u32   ke              :  1; /* 18 storage-key error uncorrected */
 	__u32   ds              :  1; /* 19 storage degradation */
-	__u32	to_be_defined_3 :  4; /* 20-23 */
+	__u32   wp              :  1; /* 20 psw mwp validity */
+	__u32   ms              :  1; /* 21 psw mask and key validity */
+	__u32   pm              :  1; /* 22 psw program mask and cc validity */
+	__u32   ia              :  1; /* 23 psw instruction address validity */
 	__u32   fa              :  1; /* 24 failing storage address validity */
-	__u32   to_be_defined_4 :  7; /* 25-31 */
+	__u32   to_be_defined_5 :  1; /* 25 */
+	__u32   ec              :  1; /* 26 external damage code validity */
+	__u32   fp              :  1; /* 27 floating point register validity */
+	__u32   gr              :  1; /* 28 general register validity */
+	__u32   cr              :  1; /* 29 control register validity */
+	__u32   to_be_defined_6 :  1; /* 30 */
+	__u32   st              :  1; /* 31 storage logical validity */
 	__u32   ie              :  1; /* 32 indirect storage error */
-	__u32	to_be_defined_5 : 31; /* 33-63 */
+	__u32   ar              :  1; /* 33 access register validity */
+	__u32   da              :  1; /* 34 delayed access exception */
+	__u32   to_be_defined_7 :  7; /* 35-41 */
+	__u32   pr              :  1; /* 42 tod programmable register validity */
+	__u32   fc              :  1; /* 43 fp control register validity */
+	__u32   ap              :  1; /* 44 ancillary report */
+	__u32   to_be_defined_8 :  1; /* 45 */
+	__u32   ct              :  1; /* 46 cpu timer validity */
+	__u32   cc              :  1; /* 47 clock comparator validity */
+	__u32	to_be_defined_9 : 16; /* 47-63 */
 };
 
 /*

include/asm-s390/lowcore.h

@@ -109,10 +109,14 @@
 
 #ifndef __s390x__
 #define __LC_PFAULT_INTPARM             0x080
+#define __LC_CPU_TIMER_SAVE_AREA        0x0D8
 #define __LC_AREGS_SAVE_AREA            0x120
+#define __LC_GPREGS_SAVE_AREA           0x180
 #define __LC_CREGS_SAVE_AREA            0x1C0
 #else /* __s390x__ */
 #define __LC_PFAULT_INTPARM             0x11B8
+#define __LC_GPREGS_SAVE_AREA           0x1280
+#define __LC_CPU_TIMER_SAVE_AREA        0x1328
 #define __LC_AREGS_SAVE_AREA            0x1340
 #define __LC_CREGS_SAVE_AREA            0x1380
 #endif /* __s390x__ */
@@ -167,7 +171,8 @@ struct _lowcore
 	__u16        subchannel_nr;            /* 0x0ba */
 	__u32        io_int_parm;              /* 0x0bc */
 	__u32        io_int_word;              /* 0x0c0 */
-        __u8         pad3[0xD8-0xC4];          /* 0x0c4 */
+        __u8         pad3[0xD4-0xC4];          /* 0x0c4 */
+	__u32        extended_save_area_addr;  /* 0x0d4 */
 	__u32        cpu_timer_save_area[2];   /* 0x0d8 */
 	__u32        clock_comp_save_area[2];  /* 0x0e0 */
 	__u32        mcck_interruption_code[2]; /* 0x0e8 */

include/asm-s390/processor.h

@@ -206,6 +206,18 @@ unsigned long get_wchan(struct task_struct *p);
 	asm volatile ("ex 0,%0" : : "i" (__LC_DIAG44_OPCODE) : "memory")
 #endif /* __s390x__ */
 
+/*
+ * Set PSW to specified value.
+ */
+static inline void __load_psw(psw_t psw)
+{
+#ifndef __s390x__
+	asm volatile ("lpsw  0(%0)" : : "a" (&psw), "m" (psw) : "cc" );
+#else
+	asm volatile ("lpswe 0(%0)" : : "a" (&psw), "m" (psw) : "cc" );
+#endif
+}
+
 /*
  * Set PSW mask to specified value, while leaving the
  * PSW addr pointing to the next instruction.
@@ -214,8 +226,8 @@ unsigned long get_wchan(struct task_struct *p);
 static inline void __load_psw_mask (unsigned long mask)
 {
 	unsigned long addr;
-
 	psw_t psw;
+
 	psw.mask = mask;
 
 #ifndef __s390x__
@@ -241,30 +253,8 @@ static inline void __load_psw_mask (unsigned long mask)
  */
 static inline void enabled_wait(void)
 {
-	unsigned long reg;
-	psw_t wait_psw;
-
-	wait_psw.mask = PSW_BASE_BITS | PSW_MASK_IO | PSW_MASK_EXT |
-		PSW_MASK_MCHECK | PSW_MASK_WAIT | PSW_DEFAULT_KEY;
-#ifndef __s390x__
-	asm volatile (
-		"    basr %0,0\n"
-		"0:  la   %0,1f-0b(%0)\n"
-		"    st   %0,4(%1)\n"
-		"    oi   4(%1),0x80\n"
-		"    lpsw 0(%1)\n"
-		"1:"
-		: "=&a" (reg) : "a" (&wait_psw), "m" (wait_psw)
-		: "memory", "cc" );
-#else /* __s390x__ */
-	asm volatile (
-		"    larl  %0,0f\n"
-		"    stg   %0,8(%1)\n"
-		"    lpswe 0(%1)\n"
-		"0:"
-		: "=&a" (reg) : "a" (&wait_psw), "m" (wait_psw)
-		: "memory", "cc" );
-#endif /* __s390x__ */
+	__load_psw_mask(PSW_BASE_BITS | PSW_MASK_IO | PSW_MASK_EXT |
+			PSW_MASK_MCHECK | PSW_MASK_WAIT | PSW_DEFAULT_KEY);
 }
 
 /*
@@ -273,13 +263,11 @@ static inline void enabled_wait(void)
 
 static inline void disabled_wait(unsigned long code)
 {
-        char psw_buffer[2*sizeof(psw_t)];
         unsigned long ctl_buf;
-        psw_t *dw_psw = (psw_t *)(((unsigned long) &psw_buffer+sizeof(psw_t)-1)
-                                  & -sizeof(psw_t));
+        psw_t dw_psw;
 
-        dw_psw->mask = PSW_BASE_BITS | PSW_MASK_WAIT;
-        dw_psw->addr = code;
+        dw_psw.mask = PSW_BASE_BITS | PSW_MASK_WAIT;
+        dw_psw.addr = code;
         /* 
          * Store status and then load disabled wait psw,
          * the processor is dead afterwards
@@ -301,7 +289,7 @@ static inline void disabled_wait(unsigned long code)
                       "    oi    0x1c0,0x10\n" /* fake protection bit */
                       "    lpsw 0(%1)"
                       : "=m" (ctl_buf)
-		      : "a" (dw_psw), "a" (&ctl_buf), "m" (dw_psw) : "cc" );
+		      : "a" (&dw_psw), "a" (&ctl_buf), "m" (dw_psw) : "cc" );
 #else /* __s390x__ */
         asm volatile ("    stctg 0,0,0(%2)\n"
                       "    ni    4(%2),0xef\n" /* switch off protection */
@@ -333,7 +321,7 @@ static inline void disabled_wait(unsigned long code)
                       "    oi    0x384(1),0x10\n" /* fake protection bit */
                       "    lpswe 0(%1)"
                       : "=m" (ctl_buf)
-		      : "a" (dw_psw), "a" (&ctl_buf),
+		      : "a" (&dw_psw), "a" (&ctl_buf),
 		        "m" (dw_psw) : "cc", "0", "1");
 #endif /* __s390x__ */
 }

include/asm-s390/ptrace.h

@@ -276,7 +276,7 @@ typedef struct
 #endif /* __s390x__ */
 
 #define PSW_KERNEL_BITS	(PSW_BASE_BITS | PSW_MASK_DAT | PSW_ASC_PRIMARY | \
-			 PSW_DEFAULT_KEY)
+			 PSW_MASK_MCHECK | PSW_DEFAULT_KEY)
 #define PSW_USER_BITS	(PSW_BASE_BITS | PSW_MASK_DAT | PSW_ASC_HOME | \
 			 PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK | \
 			 PSW_MASK_PSTATE | PSW_DEFAULT_KEY)

include/asm-s390/system.h

@@ -16,6 +16,7 @@
 #include <asm/types.h>
 #include <asm/ptrace.h>
 #include <asm/setup.h>
+#include <asm/processor.h>
 
 #ifdef __KERNEL__
 
@@ -331,9 +332,6 @@ __cmpxchg(volatile void *ptr, unsigned long old, unsigned long new, int size)
 
 #ifdef __s390x__
 
-#define __load_psw(psw) \
-        __asm__ __volatile__("lpswe 0(%0)" : : "a" (&psw), "m" (psw) : "cc" );
-
 #define __ctl_load(array, low, high) ({ \
 	typedef struct { char _[sizeof(array)]; } addrtype; \
 	__asm__ __volatile__ ( \
@@ -390,9 +388,6 @@ __cmpxchg(volatile void *ptr, unsigned long old, unsigned long new, int size)
 
 #else /* __s390x__ */
 
-#define __load_psw(psw) \
-	__asm__ __volatile__("lpsw 0(%0)" : : "a" (&psw) : "cc" );
-
 #define __ctl_load(array, low, high) ({ \
 	typedef struct { char _[sizeof(array)]; } addrtype; \
 	__asm__ __volatile__ ( \
@@ -451,6 +446,20 @@ __cmpxchg(volatile void *ptr, unsigned long old, unsigned long new, int size)
 /* For spinlocks etc */
 #define local_irq_save(x)	((x) = local_irq_disable())
 
+/*
+ * Use to set psw mask except for the first byte which
+ * won't be changed by this function.
+ */
+static inline void
+__set_psw_mask(unsigned long mask)
+{
+	local_save_flags(mask);
+	__load_psw_mask(mask);
+}
+
+#define local_mcck_enable()  __set_psw_mask(PSW_KERNEL_BITS)
+#define local_mcck_disable() __set_psw_mask(PSW_KERNEL_BITS & ~PSW_MASK_MCHECK)
+
 #ifdef CONFIG_SMP
 
 extern void smp_ctl_set_bit(int cr, int bit);

include/asm-s390/thread_info.h

@@ -96,6 +96,7 @@ static inline struct thread_info *current_thread_info(void)
 #define TIF_RESTART_SVC		4	/* restart svc with new svc number */
 #define TIF_SYSCALL_AUDIT	5	/* syscall auditing active */
 #define TIF_SINGLE_STEP		6	/* deliver sigtrap on return to user */
+#define TIF_MCCK_PENDING	7	/* machine check handling is pending */
 #define TIF_USEDFPU		16	/* FPU was used by this task this quantum (SMP) */
 #define TIF_POLLING_NRFLAG	17	/* true if poll_idle() is polling 
 					   TIF_NEED_RESCHED */
@@ -109,6 +110,7 @@ static inline struct thread_info *current_thread_info(void)
 #define _TIF_RESTART_SVC	(1<<TIF_RESTART_SVC)
 #define _TIF_SYSCALL_AUDIT	(1<<TIF_SYSCALL_AUDIT)
 #define _TIF_SINGLE_STEP	(1<<TIF_SINGLE_STEP)
+#define _TIF_MCCK_PENDING	(1<<TIF_MCCK_PENDING)
 #define _TIF_USEDFPU		(1<<TIF_USEDFPU)
 #define _TIF_POLLING_NRFLAG	(1<<TIF_POLLING_NRFLAG)
 #define _TIF_31BIT		(1<<TIF_31BIT)