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/*
 *  arch/s390/kernel/entry.S
 *    S390 low-level entry points.
 *
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 *    Copyright (C) IBM Corp. 1999,2006
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 *    Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
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 *		 Hartmut Penner (hp@de.ibm.com),
 *		 Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com),
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 *		 Heiko Carstens <heiko.carstens@de.ibm.com>
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 */

#include <linux/sys.h>
#include <linux/linkage.h>
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#include <linux/init.h>
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#include <asm/cache.h>
#include <asm/errno.h>
#include <asm/ptrace.h>
#include <asm/thread_info.h>
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#include <asm/asm-offsets.h>
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#include <asm/unistd.h>
#include <asm/page.h>

/*
 * Stack layout for the system_call stack entry.
 * The first few entries are identical to the user_regs_struct.
 */
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SP_PTREGS    =	STACK_FRAME_OVERHEAD
SP_ARGS      =	STACK_FRAME_OVERHEAD + __PT_ARGS
SP_PSW	     =	STACK_FRAME_OVERHEAD + __PT_PSW
SP_R0	     =	STACK_FRAME_OVERHEAD + __PT_GPRS
SP_R1	     =	STACK_FRAME_OVERHEAD + __PT_GPRS + 4
SP_R2	     =	STACK_FRAME_OVERHEAD + __PT_GPRS + 8
SP_R3	     =	STACK_FRAME_OVERHEAD + __PT_GPRS + 12
SP_R4	     =	STACK_FRAME_OVERHEAD + __PT_GPRS + 16
SP_R5	     =	STACK_FRAME_OVERHEAD + __PT_GPRS + 20
SP_R6	     =	STACK_FRAME_OVERHEAD + __PT_GPRS + 24
SP_R7	     =	STACK_FRAME_OVERHEAD + __PT_GPRS + 28
SP_R8	     =	STACK_FRAME_OVERHEAD + __PT_GPRS + 32
SP_R9	     =	STACK_FRAME_OVERHEAD + __PT_GPRS + 36
SP_R10	     =	STACK_FRAME_OVERHEAD + __PT_GPRS + 40
SP_R11	     =	STACK_FRAME_OVERHEAD + __PT_GPRS + 44
SP_R12	     =	STACK_FRAME_OVERHEAD + __PT_GPRS + 48
SP_R13	     =	STACK_FRAME_OVERHEAD + __PT_GPRS + 52
SP_R14	     =	STACK_FRAME_OVERHEAD + __PT_GPRS + 56
SP_R15	     =	STACK_FRAME_OVERHEAD + __PT_GPRS + 60
SP_ORIG_R2   =	STACK_FRAME_OVERHEAD + __PT_ORIG_GPR2
SP_ILC	     =	STACK_FRAME_OVERHEAD + __PT_ILC
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SP_SVCNR     =	STACK_FRAME_OVERHEAD + __PT_SVCNR
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SP_SIZE      =	STACK_FRAME_OVERHEAD + __PT_SIZE
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_TIF_WORK_SVC = (_TIF_SIGPENDING | _TIF_NOTIFY_RESUME | _TIF_NEED_RESCHED | \
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		 _TIF_MCCK_PENDING | _TIF_RESTART_SVC | _TIF_SINGLE_STEP )
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_TIF_WORK_INT = (_TIF_SIGPENDING | _TIF_NOTIFY_RESUME | _TIF_NEED_RESCHED | \
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		 _TIF_MCCK_PENDING)
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_TIF_SYSCALL = (_TIF_SYSCALL_TRACE>>8 | _TIF_SYSCALL_AUDIT>>8 | \
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		_TIF_SECCOMP>>8 | _TIF_SYSCALL_TRACEPOINT>>8)
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STACK_SHIFT = PAGE_SHIFT + THREAD_ORDER
STACK_SIZE  = 1 << STACK_SHIFT

#define BASED(name) name-system_call(%r13)

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#ifdef CONFIG_TRACE_IRQFLAGS
	.macro	TRACE_IRQS_ON
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	basr	%r2,%r0
	l	%r1,BASED(.Ltrace_irq_on_caller)
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	basr	%r14,%r1
	.endm

	.macro	TRACE_IRQS_OFF
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	basr	%r2,%r0
	l	%r1,BASED(.Ltrace_irq_off_caller)
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	basr	%r14,%r1
	.endm
#else
#define TRACE_IRQS_ON
#define TRACE_IRQS_OFF
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#endif

#ifdef CONFIG_LOCKDEP
	.macro	LOCKDEP_SYS_EXIT
	tm	SP_PSW+1(%r15),0x01	# returning to user ?
	jz	0f
	l	%r1,BASED(.Llockdep_sys_exit)
	basr	%r14,%r1
0:
	.endm
#else
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#define LOCKDEP_SYS_EXIT
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#endif

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/*
 * Register usage in interrupt handlers:
 *    R9  - pointer to current task structure
 *    R13 - pointer to literal pool
 *    R14 - return register for function calls
 *    R15 - kernel stack pointer
 */

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	.macro	UPDATE_VTIME lc_from,lc_to,lc_sum
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	lm	%r10,%r11,\lc_from
	sl	%r10,\lc_to
	sl	%r11,\lc_to+4
	bc	3,BASED(0f)
	sl	%r10,BASED(.Lc_1)
0:	al	%r10,\lc_sum
	al	%r11,\lc_sum+4
	bc	12,BASED(1f)
	al	%r10,BASED(.Lc_1)
1:	stm	%r10,%r11,\lc_sum
	.endm

	.macro	SAVE_ALL_BASE savearea
	stm	%r12,%r15,\savearea
	l	%r13,__LC_SVC_NEW_PSW+4	# load &system_call to %r13
	.endm

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	.macro	SAVE_ALL_SVC psworg,savearea
	la	%r12,\psworg
	l	%r15,__LC_KERNEL_STACK	# problem state -> load ksp
	.endm

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	.macro	SAVE_ALL_SYNC psworg,savearea
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	la	%r12,\psworg
	tm	\psworg+1,0x01		# test problem state bit
	bz	BASED(2f)		# skip stack setup save
	l	%r15,__LC_KERNEL_STACK	# problem state -> load ksp
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#ifdef CONFIG_CHECK_STACK
	b	BASED(3f)
2:	tml	%r15,STACK_SIZE - CONFIG_STACK_GUARD
	bz	BASED(stack_overflow)
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#endif
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	.endm

	.macro	SAVE_ALL_ASYNC psworg,savearea
	la	%r12,\psworg
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	tm	\psworg+1,0x01		# test problem state bit
	bnz	BASED(1f)		# from user -> load async stack
	clc	\psworg+4(4),BASED(.Lcritical_end)
	bhe	BASED(0f)
	clc	\psworg+4(4),BASED(.Lcritical_start)
	bl	BASED(0f)
	l	%r14,BASED(.Lcleanup_critical)
	basr	%r14,%r14
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	tm	1(%r12),0x01		# retest problem state after cleanup
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	bnz	BASED(1f)
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)
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#endif
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2:
	.endm

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	.macro	CREATE_STACK_FRAME psworg,savearea
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	s	%r15,BASED(.Lc_spsize)	# make room for registers & psw
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	mvc	SP_PSW(8,%r15),0(%r12)	# move user PSW to stack
	st	%r2,SP_ORIG_R2(%r15)	# store original content of gpr 2
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	icm	%r12,12,__LC_SVC_ILC
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	stm	%r0,%r11,SP_R0(%r15)	# store gprs %r0-%r11 to kernel stack
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	st	%r12,SP_ILC(%r15)
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	mvc	SP_R12(16,%r15),\savearea # move %r12-%r15 to stack
	la	%r12,0
	st	%r12,__SF_BACKCHAIN(%r15)	# clear back chain
	.endm

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	.macro	RESTORE_ALL psworg,sync
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	mvc	\psworg(8),SP_PSW(%r15) # move user PSW to lowcore
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	.if !\sync
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	ni	\psworg+1,0xfd		# clear wait state bit
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	.endif
	lm	%r0,%r15,SP_R0(%r15)	# load gprs 0-15 of user
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	stpt	__LC_EXIT_TIMER
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	lpsw	\psworg			# back to caller
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	.endm

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	.macro REENABLE_IRQS
	mvc	__SF_EMPTY(1,%r15),SP_PSW(%r15)
	ni	__SF_EMPTY(%r15),0xbf
	ssm	__SF_EMPTY(%r15)
	.endm

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/*
 * Scheduler resume function, called by switch_to
 *  gpr2 = (task_struct *) prev
 *  gpr3 = (task_struct *) next
 * Returns:
 *  gpr2 = prev
 */
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	.globl	__switch_to
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__switch_to:
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	basr	%r1,0
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__switch_to_base:
	tm	__THREAD_per(%r3),0xe8		# new process is using per ?
	bz	__switch_to_noper-__switch_to_base(%r1)	# if not we're fine
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	stctl	%c9,%c11,__SF_EMPTY(%r15)	# We are using per stuff
	clc	__THREAD_per(12,%r3),__SF_EMPTY(%r15)
	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
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__switch_to_noper:
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	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:
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	stm	%r6,%r15,__SF_GPRS(%r15)# store __switch_to registers of prev task
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	st	%r15,__THREAD_ksp(%r2)	# store kernel stack to prev->tss.ksp
	l	%r15,__THREAD_ksp(%r3)	# load kernel stack from next->tss.ksp
	lm	%r6,%r15,__SF_GPRS(%r15)# load __switch_to registers of next task
	st	%r3,__LC_CURRENT	# __LC_CURRENT = current task struct
	lctl	%c4,%c4,__TASK_pid(%r3) # load pid to control reg. 4
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	l	%r3,__THREAD_info(%r3)	# load thread_info from task struct
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	st	%r3,__LC_THREAD_INFO
	ahi	%r3,STACK_SIZE
	st	%r3,__LC_KERNEL_STACK	# __LC_KERNEL_STACK = new kernel stack
	br	%r14

__critical_start:
/*
 * SVC interrupt handler routine. System calls are synchronous events and
 * are executed with interrupts enabled.
 */

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	.globl	system_call
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system_call:
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	stpt	__LC_SYNC_ENTER_TIMER
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sysc_saveall:
	SAVE_ALL_BASE __LC_SAVE_AREA
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	SAVE_ALL_SVC __LC_SVC_OLD_PSW,__LC_SAVE_AREA
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	CREATE_STACK_FRAME __LC_SVC_OLD_PSW,__LC_SAVE_AREA
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	lh	%r7,0x8a	  # get svc number from lowcore
sysc_vtime:
	UPDATE_VTIME __LC_EXIT_TIMER,__LC_SYNC_ENTER_TIMER,__LC_USER_TIMER
sysc_stime:
	UPDATE_VTIME __LC_LAST_UPDATE_TIMER,__LC_EXIT_TIMER,__LC_SYSTEM_TIMER
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
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	ltr	%r7,%r7			# test for svc 0
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	bnz	BASED(sysc_nr_ok)	# svc number > 0
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	# svc 0: system call number in %r1
	cl	%r1,BASED(.Lnr_syscalls)
	bnl	BASED(sysc_nr_ok)
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	lr	%r7,%r1 	  # copy svc number to %r7
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sysc_nr_ok:
	mvc	SP_ARGS(4,%r15),SP_R7(%r15)
sysc_do_restart:
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	sth	%r7,SP_SVCNR(%r15)
	sll	%r7,2		  # svc number *4
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	l	%r8,BASED(.Lsysc_table)
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	tm	__TI_flags+2(%r9),_TIF_SYSCALL
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	l	%r8,0(%r7,%r8)	  # get system call addr.
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	bnz	BASED(sysc_tracesys)
	basr	%r14,%r8	  # call sys_xxxx
	st	%r2,SP_R2(%r15)   # store return value (change R2 on stack)
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sysc_return:
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	LOCKDEP_SYS_EXIT
sysc_tif:
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	tm	__TI_flags+3(%r9),_TIF_WORK_SVC
	bnz	BASED(sysc_work)  # there is work to do (signals etc.)
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sysc_restore:
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	RESTORE_ALL __LC_RETURN_PSW,1
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sysc_done:

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#
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# There is work to do, but first we need to check if we return to userspace.
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#
sysc_work:
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	tm	SP_PSW+1(%r15),0x01	# returning to user ?
	bno	BASED(sysc_restore)
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#
# One of the work bits is on. Find out which one.
#
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sysc_work_tif:
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	tm	__TI_flags+3(%r9),_TIF_MCCK_PENDING
	bo	BASED(sysc_mcck_pending)
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	tm	__TI_flags+3(%r9),_TIF_NEED_RESCHED
	bo	BASED(sysc_reschedule)
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	tm	__TI_flags+3(%r9),_TIF_SIGPENDING
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	bo	BASED(sysc_sigpending)
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	tm	__TI_flags+3(%r9),_TIF_NOTIFY_RESUME
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	bo	BASED(sysc_notify_resume)
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	tm	__TI_flags+3(%r9),_TIF_RESTART_SVC
	bo	BASED(sysc_restart)
	tm	__TI_flags+3(%r9),_TIF_SINGLE_STEP
	bo	BASED(sysc_singlestep)
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	b	BASED(sysc_return)	# beware of critical section cleanup
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#
# _TIF_NEED_RESCHED is set, call schedule
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#
sysc_reschedule:
	l	%r1,BASED(.Lschedule)
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	la	%r14,BASED(sysc_return)
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	br	%r1			# call scheduler
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#
# _TIF_MCCK_PENDING is set, call handler
#
sysc_mcck_pending:
	l	%r1,BASED(.Ls390_handle_mcck)
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	la	%r14,BASED(sysc_return)
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	br	%r1			# TIF bit will be cleared by handler

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#
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# _TIF_SIGPENDING is set, call do_signal
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#
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sysc_sigpending:
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	ni	__TI_flags+3(%r9),255-_TIF_SINGLE_STEP # clear TIF_SINGLE_STEP
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	la	%r2,SP_PTREGS(%r15)	# load pt_regs
	l	%r1,BASED(.Ldo_signal)
	basr	%r14,%r1		# call do_signal
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	tm	__TI_flags+3(%r9),_TIF_RESTART_SVC
	bo	BASED(sysc_restart)
	tm	__TI_flags+3(%r9),_TIF_SINGLE_STEP
	bo	BASED(sysc_singlestep)
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	b	BASED(sysc_return)
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#
# _TIF_NOTIFY_RESUME is set, call do_notify_resume
#
sysc_notify_resume:
	la	%r2,SP_PTREGS(%r15)	# load pt_regs
	l	%r1,BASED(.Ldo_notify_resume)
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	la	%r14,BASED(sysc_return)
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	br	%r1			# call do_notify_resume


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#
# _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
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	l	%r7,SP_R2(%r15) 	# load new svc number
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	mvc	SP_R2(4,%r15),SP_ORIG_R2(%r15) # restore first argument
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	lm	%r2,%r6,SP_R2(%r15)	# load svc arguments
	b	BASED(sysc_do_restart)	# restart svc
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#
# _TIF_SINGLE_STEP is set, call do_single_step
#
sysc_singlestep:
	ni	__TI_flags+3(%r9),255-_TIF_SINGLE_STEP # clear TIF_SINGLE_STEP
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	mvi	SP_SVCNR(%r15),0xff	# set trap indication to pgm check
	mvi	SP_SVCNR+1(%r15),0xff
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	la	%r2,SP_PTREGS(%r15)	# address of register-save area
	l	%r1,BASED(.Lhandle_per)	# load adr. of per handler
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	la	%r14,BASED(sysc_return)	# load adr. of system return
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	br	%r1			# branch to do_single_step

#
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# call tracehook_report_syscall_entry/tracehook_report_syscall_exit before
# and after the system call
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#
sysc_tracesys:
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	l	%r1,BASED(.Ltrace_entry)
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	la	%r2,SP_PTREGS(%r15)	# load pt_regs
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	la	%r3,0
	srl	%r7,2
	st	%r7,SP_R2(%r15)
	basr	%r14,%r1
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	cl	%r2,BASED(.Lnr_syscalls)
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	bnl	BASED(sysc_tracenogo)
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	l	%r8,BASED(.Lsysc_table)
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	lr	%r7,%r2
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	sll	%r7,2			# svc number *4
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	l	%r8,0(%r7,%r8)
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sysc_tracego:
	lm	%r3,%r6,SP_R3(%r15)
	l	%r2,SP_ORIG_R2(%r15)
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	basr	%r14,%r8		# call sys_xxx
	st	%r2,SP_R2(%r15)		# store return value
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sysc_tracenogo:
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	tm	__TI_flags+2(%r9),_TIF_SYSCALL
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	bz	BASED(sysc_return)
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	l	%r1,BASED(.Ltrace_exit)
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	la	%r2,SP_PTREGS(%r15)	# load pt_regs
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	la	%r14,BASED(sysc_return)
	br	%r1

#
# a new process exits the kernel with ret_from_fork
#
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	.globl	ret_from_fork
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ret_from_fork:
	l	%r13,__LC_SVC_NEW_PSW+4
	l	%r9,__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
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0:	l	%r1,BASED(.Lschedtail)
	basr	%r14,%r1
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	TRACE_IRQS_ON
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	stosm	__SF_EMPTY(%r15),0x03	# reenable interrupts
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	b	BASED(sysc_tracenogo)
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#
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# kernel_execve function needs to deal with pt_regs that is not
# at the usual place
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#
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	.globl	kernel_execve
kernel_execve:
	stm	%r12,%r15,48(%r15)
	lr	%r14,%r15
	l	%r13,__LC_SVC_NEW_PSW+4
	s	%r15,BASED(.Lc_spsize)
	st	%r14,__SF_BACKCHAIN(%r15)
	la	%r12,SP_PTREGS(%r15)
	xc	0(__PT_SIZE,%r12),0(%r12)
	l	%r1,BASED(.Ldo_execve)
	lr	%r5,%r12
	basr	%r14,%r1
	ltr	%r2,%r2
	be	BASED(0f)
	a	%r15,BASED(.Lc_spsize)
	lm	%r12,%r15,48(%r15)
	br	%r14
	# execve succeeded.
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
	xc	__SF_BACKCHAIN(4,%r15),__SF_BACKCHAIN(%r15)
	stosm	__SF_EMPTY(%r15),0x03	# reenable interrupts
	l	%r1,BASED(.Lexecve_tail)
	basr	%r14,%r1
	b	BASED(sysc_return)
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/*
 * Program check handler routine
 */

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	.globl	pgm_check_handler
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pgm_check_handler:
/*
 * First we need to check for a special case:
 * Single stepping an instruction that disables the PER event mask will
 * cause a PER event AFTER the mask has been set. Example: SVC or LPSW.
 * For a single stepped SVC the program check handler gets control after
 * the SVC new PSW has been loaded. But we want to execute the SVC first and
 * then handle the PER event. Therefore we update the SVC old PSW to point
 * to the pgm_check_handler and branch to the SVC handler after we checked
 * if we have to load the kernel stack register.
 * For every other possible cause for PER event without the PER mask set
 * we just ignore the PER event (FIXME: is there anything we have to do
 * for LPSW?).
 */
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	stpt	__LC_SYNC_ENTER_TIMER
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	SAVE_ALL_BASE __LC_SAVE_AREA
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	tm	__LC_PGM_INT_CODE+1,0x80 # check whether we got a per exception
	bnz	BASED(pgm_per)		# got per exception -> special case
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	SAVE_ALL_SYNC __LC_PGM_OLD_PSW,__LC_SAVE_AREA
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	CREATE_STACK_FRAME __LC_PGM_OLD_PSW,__LC_SAVE_AREA
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	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
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	l	%r3,__LC_PGM_ILC	# load program interruption code
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	l	%r4,__LC_TRANS_EXC_CODE
	REENABLE_IRQS
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	la	%r8,0x7f
	nr	%r8,%r3
pgm_do_call:
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	l	%r7,BASED(.Ljump_table)
	sll	%r8,2
	l	%r7,0(%r8,%r7)		# load address of handler routine
	la	%r2,SP_PTREGS(%r15)	# address of register-save area
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	basr	%r14,%r7		# branch to interrupt-handler
pgm_exit:
	b	BASED(sysc_return)
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#
# handle per exception
#
pgm_per:
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	tm	__LC_PGM_OLD_PSW,0x40	# test if per event recording is on
	bnz	BASED(pgm_per_std)	# ok, normal per event from user space
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# ok its one of the special cases, now we need to find out which one
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	clc	__LC_PGM_OLD_PSW(8),__LC_SVC_NEW_PSW
	be	BASED(pgm_svcper)
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# no interesting special case, ignore PER event
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	lm	%r12,%r15,__LC_SAVE_AREA
	lpsw	0x28
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#
# Normal per exception
#
pgm_per_std:
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	SAVE_ALL_SYNC __LC_PGM_OLD_PSW,__LC_SAVE_AREA
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	CREATE_STACK_FRAME __LC_PGM_OLD_PSW,__LC_SAVE_AREA
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	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)
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	tm	SP_PSW+1(%r15),0x01	# kernel per event ?
	bz	BASED(kernel_per)
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	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
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	l	%r3,__LC_PGM_ILC	# load program interruption code
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	l	%r4,__LC_TRANS_EXC_CODE
	REENABLE_IRQS
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	la	%r8,0x7f
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	nr	%r8,%r3 		# clear per-event-bit and ilc
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	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
	la	%r2,SP_PTREGS(%r15)	# address of register-save area
	basr	%r14,%r7		# branch to interrupt-handler
pgm_exit2:
	b	BASED(sysc_return)
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#
# it was a single stepped SVC that is causing all the trouble
#
pgm_svcper:
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	SAVE_ALL_SYNC __LC_SVC_OLD_PSW,__LC_SAVE_AREA
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	CREATE_STACK_FRAME __LC_SVC_OLD_PSW,__LC_SAVE_AREA
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	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
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	l	%r8,__TI_task(%r9)
	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
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	oi	__TI_flags+3(%r9),_TIF_SINGLE_STEP # set TIF_SINGLE_STEP
	stosm	__SF_EMPTY(%r15),0x03	# reenable interrupts
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	lm	%r2,%r6,SP_R2(%r15)	# load svc arguments
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	b	BASED(sysc_do_svc)

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#
# per was called from kernel, must be kprobes
#
kernel_per:
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	mvi	SP_SVCNR(%r15),0xff	# set trap indication to pgm check
	mvi	SP_SVCNR+1(%r15),0xff
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	la	%r2,SP_PTREGS(%r15)	# address of register-save area
	l	%r1,BASED(.Lhandle_per)	# load adr. of per handler
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	basr	%r14,%r1		# branch to do_single_step
	b	BASED(pgm_exit)
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/*
 * IO interrupt handler routine
 */

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	.globl io_int_handler
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io_int_handler:
	stck	__LC_INT_CLOCK
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	stpt	__LC_ASYNC_ENTER_TIMER
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	SAVE_ALL_BASE __LC_SAVE_AREA+16
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	SAVE_ALL_ASYNC __LC_IO_OLD_PSW,__LC_SAVE_AREA+16
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	CREATE_STACK_FRAME __LC_IO_OLD_PSW,__LC_SAVE_AREA+16
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	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
	UPDATE_VTIME __LC_LAST_UPDATE_TIMER,__LC_EXIT_TIMER,__LC_SYSTEM_TIMER
	mvc	__LC_LAST_UPDATE_TIMER(8),__LC_ASYNC_ENTER_TIMER
io_no_vtime:
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	TRACE_IRQS_OFF
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	l	%r9,__LC_THREAD_INFO	# load pointer to thread_info struct
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	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
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io_return:
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	LOCKDEP_SYS_EXIT
	TRACE_IRQS_ON
io_tif:
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	tm	__TI_flags+3(%r9),_TIF_WORK_INT
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	bnz	BASED(io_work)		# there is work to do (signals etc.)
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io_restore:
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	RESTORE_ALL __LC_RETURN_PSW,0
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io_done:
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#
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# There is work todo, find out in which context we have been interrupted:
# 1) if we return to user space we can do all _TIF_WORK_INT work
# 2) if we return to kernel code and preemptive scheduling is enabled check
#    the preemption counter and if it is zero call preempt_schedule_irq
# Before any work can be done, a switch to the kernel stack is required.
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#
io_work:
	tm	SP_PSW+1(%r15),0x01	# returning to user ?
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	bo	BASED(io_work_user)	# yes -> do resched & signal
#ifdef CONFIG_PREEMPT
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	# check for preemptive scheduling
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	icm	%r0,15,__TI_precount(%r9)
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	bnz	BASED(io_restore)	# preemption disabled
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	tm	__TI_flags+3(%r9),_TIF_NEED_RESCHED
	bno	BASED(io_restore)
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	# switch to kernel stack
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	l	%r1,SP_R15(%r15)
	s	%r1,BASED(.Lc_spsize)
	mvc	SP_PTREGS(__PT_SIZE,%r1),SP_PTREGS(%r15)
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	xc	__SF_BACKCHAIN(4,%r1),__SF_BACKCHAIN(%r1) # clear back chain
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	lr	%r15,%r1
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	# TRACE_IRQS_ON already done at io_return, call
	# TRACE_IRQS_OFF to keep things symmetrical
	TRACE_IRQS_OFF
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	l	%r1,BASED(.Lpreempt_schedule_irq)
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	basr	%r14,%r1		# call preempt_schedule_irq
	b	BASED(io_return)
#else
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	b	BASED(io_restore)
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#endif
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#
# Need to do work before returning to userspace, switch to kernel stack
#
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io_work_user:
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	l	%r1,__LC_KERNEL_STACK
	s	%r1,BASED(.Lc_spsize)
	mvc	SP_PTREGS(__PT_SIZE,%r1),SP_PTREGS(%r15)
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	xc	__SF_BACKCHAIN(4,%r1),__SF_BACKCHAIN(%r1) # clear back chain
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	lr	%r15,%r1
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#
# One of the work bits is on. Find out which one.
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# Checked are: _TIF_SIGPENDING, _TIF_NOTIFY_RESUME, _TIF_NEED_RESCHED
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#		and _TIF_MCCK_PENDING
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#
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io_work_tif:
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	tm	__TI_flags+3(%r9),_TIF_MCCK_PENDING
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	bo	BASED(io_mcck_pending)
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	tm	__TI_flags+3(%r9),_TIF_NEED_RESCHED
	bo	BASED(io_reschedule)
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	tm	__TI_flags+3(%r9),_TIF_SIGPENDING
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	bo	BASED(io_sigpending)
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	tm	__TI_flags+3(%r9),_TIF_NOTIFY_RESUME
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	bo	BASED(io_notify_resume)
	b	BASED(io_return)	# beware of critical section cleanup
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#
# _TIF_MCCK_PENDING is set, call handler
#
io_mcck_pending:
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	# TRACE_IRQS_ON already done at io_return
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	l	%r1,BASED(.Ls390_handle_mcck)
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	basr	%r14,%r1		# TIF bit will be cleared by handler
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	TRACE_IRQS_OFF
	b	BASED(io_return)
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#
# _TIF_NEED_RESCHED is set, call schedule
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#
io_reschedule:
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	# TRACE_IRQS_ON already done at io_return
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	l	%r1,BASED(.Lschedule)
	stosm	__SF_EMPTY(%r15),0x03	# reenable interrupts
	basr	%r14,%r1		# call scheduler
	stnsm	__SF_EMPTY(%r15),0xfc	# disable I/O and ext. interrupts
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	TRACE_IRQS_OFF
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	b	BASED(io_return)
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#
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# _TIF_SIGPENDING is set, call do_signal
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#
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io_sigpending:
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	# TRACE_IRQS_ON already done at io_return
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	stosm	__SF_EMPTY(%r15),0x03	# reenable interrupts
	la	%r2,SP_PTREGS(%r15)	# load pt_regs
	l	%r1,BASED(.Ldo_signal)
	basr	%r14,%r1		# call do_signal
	stnsm	__SF_EMPTY(%r15),0xfc	# disable I/O and ext. interrupts
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	TRACE_IRQS_OFF
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	b	BASED(io_return)
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#
# _TIF_SIGPENDING is set, call do_signal
#
io_notify_resume:
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	# TRACE_IRQS_ON already done at io_return
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	stosm	__SF_EMPTY(%r15),0x03	# reenable interrupts
	la	%r2,SP_PTREGS(%r15)	# load pt_regs
	l	%r1,BASED(.Ldo_notify_resume)
	basr	%r14,%r1		# call do_signal
	stnsm	__SF_EMPTY(%r15),0xfc	# disable I/O and ext. interrupts
	TRACE_IRQS_OFF
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	b	BASED(io_return)
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/*
 * External interrupt handler routine
 */

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	.globl	ext_int_handler
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ext_int_handler:
	stck	__LC_INT_CLOCK
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	stpt	__LC_ASYNC_ENTER_TIMER
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	SAVE_ALL_BASE __LC_SAVE_AREA+16
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	SAVE_ALL_ASYNC __LC_EXT_OLD_PSW,__LC_SAVE_AREA+16
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	CREATE_STACK_FRAME __LC_EXT_OLD_PSW,__LC_SAVE_AREA+16
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	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
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	TRACE_IRQS_OFF
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	la	%r2,SP_PTREGS(%r15)	# address of register-save area
	lh	%r3,__LC_EXT_INT_CODE	# get interruption code
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	l	%r1,BASED(.Ldo_extint)
	basr	%r14,%r1
	b	BASED(io_return)

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__critical_end:

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/*
 * Machine check handler routines
 */

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	.globl mcck_int_handler
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mcck_int_handler:
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	stck	__LC_MCCK_CLOCK
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	spt	__LC_CPU_TIMER_SAVE_AREA	# revalidate cpu timer
	lm	%r0,%r15,__LC_GPREGS_SAVE_AREA	# revalidate gprs
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	SAVE_ALL_BASE __LC_SAVE_AREA+32
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	la	%r12,__LC_MCK_OLD_PSW
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	tm	__LC_MCCK_CODE,0x80	# system damage?
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	bo	BASED(mcck_int_main)	# yes -> rest of mcck code invalid
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	mvc	__LC_MCCK_ENTER_TIMER(8),__LC_CPU_TIMER_SAVE_AREA
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	tm	__LC_MCCK_CODE+5,0x02	# stored cpu timer value valid?
	bo	BASED(1f)
	la	%r14,__LC_SYNC_ENTER_TIMER
	clc	0(8,%r14),__LC_ASYNC_ENTER_TIMER
	bl	BASED(0f)
	la	%r14,__LC_ASYNC_ENTER_TIMER
0:	clc	0(8,%r14),__LC_EXIT_TIMER
	bl	BASED(0f)
	la	%r14,__LC_EXIT_TIMER
0:	clc	0(8,%r14),__LC_LAST_UPDATE_TIMER
	bl	BASED(0f)
	la	%r14,__LC_LAST_UPDATE_TIMER
0:	spt	0(%r14)
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	mvc	__LC_MCCK_ENTER_TIMER(8),0(%r14)
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	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
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	tm	__LC_MCCK_CODE+2,0x08	# mwp of old psw valid?
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	bno	BASED(mcck_no_vtime)	# no -> skip cleanup critical
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	tm	SP_PSW+1(%r15),0x01	# interrupting from user ?
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	bz	BASED(mcck_no_vtime)
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	UPDATE_VTIME __LC_EXIT_TIMER,__LC_MCCK_ENTER_TIMER,__LC_USER_TIMER
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	UPDATE_VTIME __LC_LAST_UPDATE_TIMER,__LC_EXIT_TIMER,__LC_SYSTEM_TIMER
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	mvc	__LC_LAST_UPDATE_TIMER(8),__LC_MCCK_ENTER_TIMER
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mcck_no_vtime:
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	l	%r9,__LC_THREAD_INFO	# load pointer to thread_info struct
	la	%r2,SP_PTREGS(%r15)	# load pt_regs
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	l	%r1,BASED(.Ls390_mcck)
	basr	%r14,%r1		# call machine check handler
	tm	SP_PSW+1(%r15),0x01	# returning to user ?
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	bno	BASED(mcck_return)
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	l	%r1,__LC_KERNEL_STACK	# switch to kernel stack
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	s	%r1,BASED(.Lc_spsize)
	mvc	SP_PTREGS(__PT_SIZE,%r1),SP_PTREGS(%r15)
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	xc	__SF_BACKCHAIN(4,%r1),__SF_BACKCHAIN(%r1) # clear back chain
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	lr	%r15,%r1
	stosm	__SF_EMPTY(%r15),0x04	# turn dat on
	tm	__TI_flags+3(%r9),_TIF_MCCK_PENDING
	bno	BASED(mcck_return)
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	TRACE_IRQS_OFF
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	l	%r1,BASED(.Ls390_handle_mcck)
	basr	%r14,%r1		# call machine check handler
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	TRACE_IRQS_ON
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mcck_return:
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	mvc	__LC_RETURN_MCCK_PSW(8),SP_PSW(%r15) # move return PSW
	ni	__LC_RETURN_MCCK_PSW+1,0xfd # clear wait state bit
	tm	__LC_RETURN_MCCK_PSW+1,0x01 # returning to user ?
	bno	BASED(0f)
	lm	%r0,%r15,SP_R0(%r15)	# load gprs 0-15
	stpt	__LC_EXIT_TIMER
	lpsw	__LC_RETURN_MCCK_PSW	# back to caller
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0:	lm	%r0,%r15,SP_R0(%r15)	# load gprs 0-15
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	lpsw	__LC_RETURN_MCCK_PSW	# back to caller

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	RESTORE_ALL __LC_RETURN_MCCK_PSW,0
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/*
 * Restart interruption handler, kick starter for additional CPUs
 */
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#ifdef CONFIG_SMP
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	__CPUINIT
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	.globl restart_int_handler
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restart_int_handler:
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	basr	%r1,0
restart_base:
	spt	restart_vtime-restart_base(%r1)
	stck	__LC_LAST_UPDATE_CLOCK
	mvc	__LC_LAST_UPDATE_TIMER(8),restart_vtime-restart_base(%r1)
	mvc	__LC_EXIT_TIMER(8),restart_vtime-restart_base(%r1)
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	l	%r15,__LC_SAVE_AREA+60	# load ksp
	lctl	%c0,%c15,__LC_CREGS_SAVE_AREA # get new ctl regs
	lam	%a0,%a15,__LC_AREGS_SAVE_AREA
	lm	%r6,%r15,__SF_GPRS(%r15) # load registers from clone
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	l	%r1,__LC_THREAD_INFO
	mvc	__LC_USER_TIMER(8),__TI_user_timer(%r1)
	mvc	__LC_SYSTEM_TIMER(8),__TI_system_timer(%r1)
	xc	__LC_STEAL_TIMER(8),__LC_STEAL_TIMER
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	stosm	__SF_EMPTY(%r15),0x04	# now we can turn dat on
	basr	%r14,0
	l	%r14,restart_addr-.(%r14)
	br	%r14			# branch to start_secondary
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restart_addr:
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	.long	start_secondary
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	.align	8
restart_vtime:
	.long	0x7fffffff,0xffffffff
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	.previous
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#else
/*
 * If we do not run with SMP enabled, let the new CPU crash ...
 */
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	.globl restart_int_handler
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restart_int_handler:
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	basr	%r1,0
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restart_base:
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	lpsw	restart_crash-restart_base(%r1)
	.align	8
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restart_crash:
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	.long	0x000a0000,0x00000000
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restart_go:
#endif

#ifdef CONFIG_CHECK_STACK
/*
 * The synchronous or the asynchronous stack overflowed. We are dead.
 * No need to properly save the registers, we are going to panic anyway.
 * Setup a pt_regs so that show_trace can provide a good call trace.
 */
stack_overflow:
	l	%r15,__LC_PANIC_STACK	# change to panic stack
	sl	%r15,BASED(.Lc_spsize)
	mvc	SP_PSW(8,%r15),0(%r12)	# move user PSW to stack
	stm	%r0,%r11,SP_R0(%r15)	# store gprs %r0-%r11 to kernel stack
	la	%r1,__LC_SAVE_AREA
	ch	%r12,BASED(.L0x020)	# old psw addr == __LC_SVC_OLD_PSW ?
	be	BASED(0f)
	ch	%r12,BASED(.L0x028)	# old psw addr == __LC_PGM_OLD_PSW ?
	be	BASED(0f)
	la	%r1,__LC_SAVE_AREA+16
0:	mvc	SP_R12(16,%r15),0(%r1)	# move %r12-%r15 to stack
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	xc	__SF_BACKCHAIN(4,%r15),__SF_BACKCHAIN(%r15) # clear back chain
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	l	%r1,BASED(1f)		# branch to kernel_stack_overflow
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	la	%r2,SP_PTREGS(%r15)	# load pt_regs
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	br	%r1
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1:	.long	kernel_stack_overflow
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#endif

cleanup_table_system_call:
	.long	system_call + 0x80000000, sysc_do_svc + 0x80000000
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cleanup_table_sysc_tif:
	.long	sysc_tif + 0x80000000, sysc_restore + 0x80000000
cleanup_table_sysc_restore:
	.long	sysc_restore + 0x80000000, sysc_done + 0x80000000
cleanup_table_io_tif:
	.long	io_tif + 0x80000000, io_restore + 0x80000000
cleanup_table_io_restore:
	.long	io_restore + 0x80000000, io_done + 0x80000000
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cleanup_critical:
	clc	4(4,%r12),BASED(cleanup_table_system_call)
	bl	BASED(0f)
	clc	4(4,%r12),BASED(cleanup_table_system_call+4)
	bl	BASED(cleanup_system_call)
0:
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	clc	4(4,%r12),BASED(cleanup_table_sysc_tif)
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	bl	BASED(0f)
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	clc	4(4,%r12),BASED(cleanup_table_sysc_tif+4)
	bl	BASED(cleanup_sysc_tif)
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0:
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	clc	4(4,%r12),BASED(cleanup_table_sysc_restore)
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	bl	BASED(0f)
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	clc	4(4,%r12),BASED(cleanup_table_sysc_restore+4)
	bl	BASED(cleanup_sysc_restore)
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	clc	4(4,%r12),BASED(cleanup_table_io_tif)
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	bl	BASED(0f)
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	clc	4(4,%r12),BASED(cleanup_table_io_tif+4)
	bl	BASED(cleanup_io_tif)
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0:
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	clc	4(4,%r12),BASED(cleanup_table_io_restore)
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	bl	BASED(0f)
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	clc	4(4,%r12),BASED(cleanup_table_io_restore+4)
	bl	BASED(cleanup_io_restore)
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0:
	br	%r14

cleanup_system_call:
	mvc	__LC_RETURN_PSW(8),0(%r12)
	clc	__LC_RETURN_PSW+4(4),BASED(cleanup_system_call_insn+4)
	bh	BASED(0f)
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	mvc	__LC_SYNC_ENTER_TIMER(8),__LC_MCCK_ENTER_TIMER
	c	%r12,BASED(.Lmck_old_psw)
	be	BASED(0f)
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	mvc	__LC_SYNC_ENTER_TIMER(8),__LC_ASYNC_ENTER_TIMER
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0:	c	%r12,BASED(.Lmck_old_psw)
	la	%r12,__LC_SAVE_AREA+32
	be	BASED(0f)
	la	%r12,__LC_SAVE_AREA+16
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0:	clc	__LC_RETURN_PSW+4(4),BASED(cleanup_system_call_insn+8)
	bhe	BASED(cleanup_vtime)
	clc	__LC_RETURN_PSW+4(4),BASED(cleanup_system_call_insn)
	bh	BASED(0f)
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	mvc	__LC_SAVE_AREA(16),0(%r12)
0:	st	%r13,4(%r12)
	st	%r12,__LC_SAVE_AREA+48	# argh
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	SAVE_ALL_SYNC __LC_SVC_OLD_PSW,__LC_SAVE_AREA
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	CREATE_STACK_FRAME __LC_SVC_OLD_PSW,__LC_SAVE_AREA
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	l	%r12,__LC_SAVE_AREA+48	# argh
	st	%r15,12(%r12)
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	lh	%r7,0x8a
cleanup_vtime:
	clc	__LC_RETURN_PSW+4(4),BASED(cleanup_system_call_insn+12)
	bhe	BASED(cleanup_stime)
	UPDATE_VTIME __LC_EXIT_TIMER,__LC_SYNC_ENTER_TIMER,__LC_USER_TIMER
cleanup_stime:
	clc	__LC_RETURN_PSW+4(4),BASED(cleanup_system_call_insn+16)
	bh	BASED(cleanup_update)
	UPDATE_VTIME __LC_LAST_UPDATE_TIMER,__LC_EXIT_TIMER,__LC_SYSTEM_TIMER
cleanup_update:
	mvc	__LC_LAST_UPDATE_TIMER(8),__LC_SYNC_ENTER_TIMER
	mvc	__LC_RETURN_PSW+4(4),BASED(cleanup_table_system_call+4)
	la	%r12,__LC_RETURN_PSW
	br	%r14
cleanup_system_call_insn:
	.long	sysc_saveall + 0x80000000
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	.long	system_call + 0x80000000
	.long	sysc_vtime + 0x80000000
	.long	sysc_stime + 0x80000000
	.long	sysc_update + 0x80000000
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cleanup_sysc_tif:
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	mvc	__LC_RETURN_PSW(4),0(%r12)
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	mvc	__LC_RETURN_PSW+4(4),BASED(cleanup_table_sysc_tif)
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	la	%r12,__LC_RETURN_PSW
	br	%r14

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cleanup_sysc_restore:
	clc	4(4,%r12),BASED(cleanup_sysc_restore_insn)
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	be	BASED(2f)
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	mvc	__LC_EXIT_TIMER(8),__LC_MCCK_ENTER_TIMER
	c	%r12,BASED(.Lmck_old_psw)
	be	BASED(0f)
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	mvc	__LC_EXIT_TIMER(8),__LC_ASYNC_ENTER_TIMER
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0:	clc	4(4,%r12),BASED(cleanup_sysc_restore_insn+4)
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	be	BASED(2f)
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	mvc	__LC_RETURN_PSW(8),SP_PSW(%r15)
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	c	%r12,BASED(.Lmck_old_psw)
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	la	%r12,__LC_SAVE_AREA+32
	be	BASED(1f)
	la	%r12,__LC_SAVE_AREA+16
1:	mvc	0(16,%r12),SP_R12(%r15)
	lm	%r0,%r11,SP_R0(%r15)
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