/*
* arch/s390/kernel/entry64.S
* S390 low-level entry points.
*
* Copyright (C) IBM Corp. 1999,2010
* 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/linkage.h>
#include <linux/init.h>
#include <asm/cache.h>
#include <asm/errno.h>
#include <asm/ptrace.h>
#include <asm/thread_info.h>
#include <asm/asm-offsets.h>
#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.
*/
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 + 8
SP_R2 = STACK_FRAME_OVERHEAD + __PT_GPRS + 16
SP_R3 = STACK_FRAME_OVERHEAD + __PT_GPRS + 24
SP_R4 = STACK_FRAME_OVERHEAD + __PT_GPRS + 32
SP_R5 = STACK_FRAME_OVERHEAD + __PT_GPRS + 40
SP_R6 = STACK_FRAME_OVERHEAD + __PT_GPRS + 48
SP_R7 = STACK_FRAME_OVERHEAD + __PT_GPRS + 56
SP_R8 = STACK_FRAME_OVERHEAD + __PT_GPRS + 64
SP_R9 = STACK_FRAME_OVERHEAD + __PT_GPRS + 72
SP_R10 = STACK_FRAME_OVERHEAD + __PT_GPRS + 80
SP_R11 = STACK_FRAME_OVERHEAD + __PT_GPRS + 88
SP_R12 = STACK_FRAME_OVERHEAD + __PT_GPRS + 96
SP_R13 = STACK_FRAME_OVERHEAD + __PT_GPRS + 104
SP_R14 = STACK_FRAME_OVERHEAD + __PT_GPRS + 112
SP_R15 = STACK_FRAME_OVERHEAD + __PT_GPRS + 120
SP_ORIG_R2 = STACK_FRAME_OVERHEAD + __PT_ORIG_GPR2
SP_ILC = STACK_FRAME_OVERHEAD + __PT_ILC
SP_SVCNR = STACK_FRAME_OVERHEAD + __PT_SVCNR
SP_SIZE = STACK_FRAME_OVERHEAD + __PT_SIZE
STACK_SHIFT = PAGE_SHIFT + THREAD_ORDER
STACK_SIZE = 1 << STACK_SHIFT
_TIF_WORK_SVC = (_TIF_SIGPENDING | _TIF_NOTIFY_RESUME | _TIF_NEED_RESCHED | \
_TIF_MCCK_PENDING | _TIF_RESTART_SVC | _TIF_PER_TRAP )
_TIF_WORK_INT = (_TIF_SIGPENDING | _TIF_NOTIFY_RESUME | _TIF_NEED_RESCHED | \
_TIF_MCCK_PENDING)
_TIF_SYSCALL = (_TIF_SYSCALL_TRACE>>8 | _TIF_SYSCALL_AUDIT>>8 | \
_TIF_SECCOMP>>8 | _TIF_SYSCALL_TRACEPOINT>>8)
#define BASED(name) name-system_call(%r13)
.macro HANDLE_SIE_INTERCEPT
#if defined(CONFIG_KVM) || defined(CONFIG_KVM_MODULE)
lg %r3,__LC_SIE_HOOK
ltgr %r3,%r3
jz 0f
basr %r14,%r3
0:
#endif
.endm
#ifdef CONFIG_TRACE_IRQFLAGS
.macro TRACE_IRQS_ON
basr %r2,%r0
brasl %r14,trace_hardirqs_on_caller
.endm
.macro TRACE_IRQS_OFF
basr %r2,%r0
brasl %r14,trace_hardirqs_off_caller
.endm
#else
#define TRACE_IRQS_ON
#define TRACE_IRQS_OFF
#endif
#ifdef CONFIG_LOCKDEP
.macro LOCKDEP_SYS_EXIT
tm SP_PSW+1(%r15),0x01 # returning to user ?
jz 0f
brasl %r14,lockdep_sys_exit
0:
.endm
#else
#define LOCKDEP_SYS_EXIT
#endif
.macro UPDATE_VTIME lc_from,lc_to,lc_sum
lg %r10,\lc_from
slg %r10,\lc_to
alg %r10,\lc_sum
stg %r10,\lc_sum
.endm
/*
* 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
*/
.macro SAVE_ALL_SVC psworg,savearea
stmg %r11,%r15,\savearea
lg %r15,__LC_KERNEL_STACK # problem state -> load ksp
aghi %r15,-SP_SIZE # make room for registers & psw
lg %r11,__LC_LAST_BREAK
.endm
.macro SAVE_ALL_PGM psworg,savearea
stmg %r11,%r15,\savearea
tm \psworg+1,0x01 # test problem state bit
#ifdef CONFIG_CHECK_STACK
jnz 1f
tml %r15,STACK_SIZE - CONFIG_STACK_GUARD
jnz 2f
la %r12,\psworg
j stack_overflow
#else
jz 2f
#endif
1: lg %r15,__LC_KERNEL_STACK # problem state -> load ksp
2: aghi %r15,-SP_SIZE # make room for registers & psw
larl %r13,system_call
lg %r11,__LC_LAST_BREAK
.endm
.macro SAVE_ALL_ASYNC psworg,savearea
stmg %r11,%r15,\savearea
larl %r13,system_call
lg %r11,__LC_LAST_BREAK
la %r12,\psworg
tm \psworg+1,0x01 # test problem state bit
jnz 1f # from user -> load kernel stack
clc \psworg+8(8),BASED(.Lcritical_end)
jhe 0f
clc \psworg+8(8),BASED(.Lcritical_start)
jl 0f
brasl %r14,cleanup_critical
tm 1(%r12),0x01 # retest problem state after cleanup
jnz 1f
0: lg %r14,__LC_ASYNC_STACK # are we already on the async. stack ?
slgr %r14,%r15
srag %r14,%r14,STACK_SHIFT
#ifdef CONFIG_CHECK_STACK
jnz 1f
tml %r15,STACK_SIZE - CONFIG_STACK_GUARD
jnz 2f
j stack_overflow
#else
jz 2f
#endif
1: lg %r15,__LC_ASYNC_STACK # load async stack
2: aghi %r15,-SP_SIZE # make room for registers & psw
.endm
.macro CREATE_STACK_FRAME savearea
xc __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
stg %r2,SP_ORIG_R2(%r15) # store original content of gpr 2
mvc SP_R11(40,%r15),\savearea # move %r11-%r15 to stack
stmg %r0,%r10,SP_R0(%r15) # store gprs %r0-%r10 to kernel stack
.endm
.macro RESTORE_ALL psworg,sync
mvc \psworg(16),SP_PSW(%r15) # move user PSW to lowcore
.if !\sync
ni \psworg+1,0xfd # clear wait state bit
.endif
lg %r14,__LC_VDSO_PER_CPU
lmg %r0,%r13,SP_R0(%r15) # load gprs 0-13 of user
stpt __LC_EXIT_TIMER
mvc __VDSO_ECTG_BASE(16,%r14),__LC_EXIT_TIMER
lmg %r14,%r15,SP_R14(%r15) # load grps 14-15 of user
lpswe \psworg # back to caller
.endm
.macro LAST_BREAK
srag %r10,%r11,23
jz 0f
stg %r11,__TI_last_break(%r12)
0:
.endm
.macro REENABLE_IRQS
mvc __SF_EMPTY(1,%r15),SP_PSW(%r15)
ni __SF_EMPTY(%r15),0xbf
ssm __SF_EMPTY(%r15)
.endm
.section .kprobes.text, "ax"
/*
* Scheduler resume function, called by switch_to
* gpr2 = (task_struct *) prev
* gpr3 = (task_struct *) next
* Returns:
* gpr2 = prev
*/
.globl __switch_to
__switch_to:
lg %r4,__THREAD_info(%r2) # get thread_info of prev
lg %r5,__THREAD_info(%r3) # get thread_info of next
tm __TI_flags+7(%r4),_TIF_MCCK_PENDING # machine check pending?
jz 0f
ni __TI_flags+7(%r4),255-_TIF_MCCK_PENDING # clear flag in prev
oi __TI_flags+7(%r5),_TIF_MCCK_PENDING # set it in next
0: stmg %r6,%r15,__SF_GPRS(%r15) # store gprs of prev task
stg %r15,__THREAD_ksp(%r2) # store kernel stack of prev
lg %r15,__THREAD_ksp(%r3) # load kernel stack of next
lctl %c4,%c4,__TASK_pid(%r3) # load pid to control reg. 4
lmg %r6,%r15,__SF_GPRS(%r15) # load gprs of next task
stg %r3,__LC_CURRENT # store task struct of next
stg %r5,__LC_THREAD_INFO # store thread info of next
aghi %r5,STACK_SIZE # end of kernel stack of next
stg %r5,__LC_KERNEL_STACK # store end of kernel stack
br %r14
__critical_start:
/*
* SVC interrupt handler routine. System calls are synchronous events and
* are executed with interrupts enabled.
*/
.globl system_call
system_call:
stpt __LC_SYNC_ENTER_TIMER
sysc_saveall:
SAVE_ALL_SVC __LC_SVC_OLD_PSW,__LC_SAVE_AREA
CREATE_STACK_FRAME __LC_SAVE_AREA
mvc SP_PSW(16,%r15),__LC_SVC_OLD_PSW
mvc SP_ILC(4,%r15),__LC_SVC_ILC
lg %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:
UPDATE_VTIME __LC_LAST_UPDATE_TIMER,__LC_EXIT_TIMER,__LC_SYSTEM_TIMER
sysc_update:
mvc __LC_LAST_UPDATE_TIMER(8),__LC_SYNC_ENTER_TIMER
LAST_BREAK
sysc_do_svc:
llgh %r7,SP_SVCNR(%r15)
slag %r7,%r7,2 # shift and test for svc 0
jnz sysc_nr_ok
# svc 0: system call number in %r1
llgfr %r1,%r1 # clear high word in r1
cghi %r1,NR_syscalls
jnl sysc_nr_ok
sth %r1,SP_SVCNR(%r15)
slag %r7,%r1,2 # shift and test for svc 0
sysc_nr_ok:
larl %r10,sys_call_table
#ifdef CONFIG_COMPAT
tm __TI_flags+5(%r12),(_TIF_31BIT>>16) # running in 31 bit mode ?
jno sysc_noemu
larl %r10,sys_call_table_emu # use 31 bit emulation system calls
sysc_noemu:
#endif
tm __TI_flags+6(%r12),_TIF_SYSCALL
mvc SP_ARGS(8,%r15),SP_R7(%r15)
lgf %r8,0(%r7,%r10) # load address of system call routine
jnz sysc_tracesys
basr %r14,%r8 # call sys_xxxx
stg %r2,SP_R2(%r15) # store return value (change R2 on stack)
sysc_return:
LOCKDEP_SYS_EXIT
sysc_tif:
tm __TI_flags+7(%r12),_TIF_WORK_SVC
jnz sysc_work # there is work to do (signals etc.)
sysc_restore:
RESTORE_ALL __LC_RETURN_PSW,1
sysc_done:
#
# There is work to do, but first we need to check if we return to userspace.
#
sysc_work:
tm SP_PSW+1(%r15),0x01 # returning to user ?
jno sysc_restore
#
# One of the work bits is on. Find out which one.
#
sysc_work_tif:
tm __TI_flags+7(%r12),_TIF_MCCK_PENDING
jo sysc_mcck_pending
tm __TI_flags+7(%r12),_TIF_NEED_RESCHED
jo sysc_reschedule
tm __TI_flags+7(%r12),_TIF_SIGPENDING
jo sysc_sigpending
tm __TI_flags+7(%r12),_TIF_NOTIFY_RESUME
jo sysc_notify_resume
tm __TI_flags+7(%r12),_TIF_RESTART_SVC
jo sysc_restart
tm __TI_flags+7(%r12),_TIF_PER_TRAP
jo sysc_singlestep
j sysc_return # beware of critical section cleanup
#
# _TIF_NEED_RESCHED is set, call schedule
#
sysc_reschedule:
larl %r14,sysc_return
jg schedule # return point is sysc_return
#
# _TIF_MCCK_PENDING is set, call handler
#
sysc_mcck_pending:
larl %r14,sysc_return
jg s390_handle_mcck # TIF bit will be cleared by handler
#
# _TIF_SIGPENDING is set, call do_signal
#
sysc_sigpending:
ni __TI_flags+7(%r12),255-_TIF_PER_TRAP # clear TIF_PER_TRAP
la %r2,SP_PTREGS(%r15) # load pt_regs
brasl %r14,do_signal # call do_signal
tm __TI_flags+7(%r12),_TIF_RESTART_SVC
jo sysc_restart
tm __TI_flags+7(%r12),_TIF_PER_TRAP
jo sysc_singlestep
j sysc_return
#
# _TIF_NOTIFY_RESUME is set, call do_notify_resume
#
sysc_notify_resume:
la %r2,SP_PTREGS(%r15) # load pt_regs
larl %r14,sysc_return
jg do_notify_resume # call do_notify_resume
#
# _TIF_RESTART_SVC is set, set up registers and restart svc
#
sysc_restart:
ni __TI_flags+7(%r12),255-_TIF_RESTART_SVC # clear TIF_RESTART_SVC
lg %r7,SP_R2(%r15) # load new svc number
mvc SP_R2(8,%r15),SP_ORIG_R2(%r15) # restore first argument
lmg %r2,%r6,SP_R2(%r15) # load svc arguments
sth %r7,SP_SVCNR(%r15)
slag %r7,%r7,2
j sysc_nr_ok # restart svc
#
# _TIF_PER_TRAP is set, call do_per_trap
#
sysc_singlestep:
ni __TI_flags+7(%r12),255-_TIF_PER_TRAP # clear TIF_PER_TRAP
xc SP_SVCNR(2,%r15),SP_SVCNR(%r15) # clear svc number
la %r2,SP_PTREGS(%r15) # address of register-save area
larl %r14,sysc_return # load adr. of system return
jg do_per_trap
#
# call tracehook_report_syscall_entry/tracehook_report_syscall_exit before
# and after the system call
#
sysc_tracesys:
la %r2,SP_PTREGS(%r15) # load pt_regs
la %r3,0
llgh %r0,SP_SVCNR(%r15)
stg %r0,SP_R2(%r15)
brasl %r14,do_syscall_trace_enter
lghi %r0,NR_syscalls
clgr %r0,%r2
jnh sysc_tracenogo
sllg %r7,%r2,2 # svc number *4
lgf %r8,0(%r7,%r10)
sysc_tracego:
lmg %r3,%r6,SP_R3(%r15)
mvc SP_ARGS(8,%r15),SP_R7(%r15)
lg %r2,SP_ORIG_R2(%r15)
basr %r14,%r8 # call sys_xxx
stg %r2,SP_R2(%r15) # store return value
sysc_tracenogo:
tm __TI_flags+6(%r12),_TIF_SYSCALL
jz sysc_return
la %r2,SP_PTREGS(%r15) # load pt_regs
larl %r14,sysc_return # return point is sysc_return
jg do_syscall_trace_exit
#
# a new process exits the kernel with ret_from_fork
#
.globl ret_from_fork
ret_from_fork:
lg %r13,__LC_SVC_NEW_PSW+8
lg %r12,__LC_THREAD_INFO # load pointer to thread_info struct
tm SP_PSW+1(%r15),0x01 # forking a kernel thread ?
jo 0f
stg %r15,SP_R15(%r15) # store stack pointer for new kthread
0: brasl %r14,schedule_tail
TRACE_IRQS_ON
stosm 24(%r15),0x03 # reenable interrupts
j sysc_tracenogo
#
# kernel_execve function needs to deal with pt_regs that is not
# at the usual place
#
.globl kernel_execve
kernel_execve:
stmg %r12,%r15,96(%r15)
lgr %r14,%r15
aghi %r15,-SP_SIZE
stg %r14,__SF_BACKCHAIN(%r15)
la %r12,SP_PTREGS(%r15)
xc 0(__PT_SIZE,%r12),0(%r12)
lgr %r5,%r12
brasl %r14,do_execve
ltgfr %r2,%r2
je 0f
aghi %r15,SP_SIZE
lmg %r12,%r15,96(%r15)
br %r14
# execve succeeded.
0: stnsm __SF_EMPTY(%r15),0xfc # disable interrupts
lg %r15,__LC_KERNEL_STACK # load ksp
aghi %r15,-SP_SIZE # make room for registers & psw
lg %r13,__LC_SVC_NEW_PSW+8
mvc SP_PTREGS(__PT_SIZE,%r15),0(%r12) # copy pt_regs
lg %r12,__LC_THREAD_INFO
xc __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
stosm __SF_EMPTY(%r15),0x03 # reenable interrupts
brasl %r14,execve_tail
j sysc_return
/*
* Program check handler routine
*/
.globl pgm_check_handler
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?).
*/
stpt __LC_SYNC_ENTER_TIMER
tm __LC_PGM_INT_CODE+1,0x80 # check whether we got a per exception
jnz pgm_per # got per exception -> special case
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(16,%r15),__LC_PGM_OLD_PSW
lg %r12,__LC_THREAD_INFO # load pointer to thread_info struct
tm SP_PSW+1(%r15),0x01 # interrupting from user ?
jz 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
LAST_BREAK
pgm_no_vtime:
HANDLE_SIE_INTERCEPT
stg %r11,SP_ARGS(%r15)
lgf %r3,__LC_PGM_ILC # load program interruption code
lg %r4,__LC_TRANS_EXC_CODE
REENABLE_IRQS
lghi %r8,0x7f
ngr %r8,%r3
sll %r8,3
larl %r1,pgm_check_table
lg %r1,0(%r8,%r1) # load address of handler routine
la %r2,SP_PTREGS(%r15) # address of register-save area
basr %r14,%r1 # branch to interrupt-handler
pgm_exit:
j sysc_return
#
# handle per exception
#
pgm_per:
tm __LC_PGM_OLD_PSW,0x40 # test if per event recording is on
jnz pgm_per_std # ok, normal per event from user space
# ok its one of the special cases, now we need to find out which one
clc __LC_PGM_OLD_PSW(16),__LC_SVC_NEW_PSW
je pgm_svcper
# no interesting special case, ignore PER event
lpswe __LC_PGM_OLD_PSW
#
# Normal per exception
#
pgm_per_std:
SAVE_ALL_PGM __LC_PGM_OLD_PSW,__LC_SAVE_AREA
CREATE_STACK_FRAME __LC_SAVE_AREA
mvc SP_PSW(16,%r15),__LC_PGM_OLD_PSW
lg %r12,__LC_THREAD_INFO # load pointer to thread_info struct
tm SP_PSW+1(%r15),0x01 # interrupting from user ?
jz 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
LAST_BREAK
pgm_no_vtime2:
HANDLE_SIE_INTERCEPT
lg %r1,__TI_task(%r12)
tm SP_PSW+1(%r15),0x01 # kernel per event ?
jz kernel_per
mvc __THREAD_per_cause(2,%r1),__LC_PER_CAUSE
mvc __THREAD_per_address(8,%r1),__LC_PER_ADDRESS
mvc __THREAD_per_paid(1,%r1),__LC_PER_PAID
oi __TI_flags+7(%r12),_TIF_PER_TRAP # set TIF_PER_TRAP
lgf %r3,__LC_PGM_ILC # load program interruption code
lg %r4,__LC_TRANS_EXC_CODE
REENABLE_IRQS
lghi %r8,0x7f
ngr %r8,%r3 # clear per-event-bit and ilc
je pgm_exit2
sll %r8,3
larl %r1,pgm_check_table
lg %r1,0(%r8,%r1) # load address of handler routine
la %r2,SP_PTREGS(%r15) # address of register-save area
basr %r14,%r1 # branch to interrupt-handler
pgm_exit2:
j sysc_return
#
# it was a single stepped SVC that is causing all the trouble
#
pgm_svcper:
SAVE_ALL_PGM __LC_SVC_OLD_PSW,__LC_SAVE_AREA
CREATE_STACK_FRAME __LC_SAVE_AREA
mvc SP_PSW(16,%r15),__LC_SVC_OLD_PSW
mvc SP_ILC(4,%r15),__LC_SVC_ILC
lg %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
LAST_BREAK
lg %r8,__TI_task(%r12)
mvc __THREAD_per_cause(2,%r8),__LC_PER_CAUSE
mvc __THREAD_per_address(8,%r8),__LC_PER_ADDRESS
mvc __THREAD_per_paid(1,%r8),__LC_PER_PAID
oi __TI_flags+7(%r12),_TIF_PER_TRAP # set TIF_PER_TRAP
stosm __SF_EMPTY(%r15),0x03 # reenable interrupts
lmg %r2,%r6,SP_R2(%r15) # load svc arguments
j sysc_do_svc
#
# per was called from kernel, must be kprobes
#
kernel_per:
REENABLE_IRQS
xc SP_SVCNR(2,%r15),SP_SVCNR(%r15) # clear svc number
la %r2,SP_PTREGS(%r15) # address of register-save area
brasl %r14,do_per_trap
j pgm_exit
/*
* IO interrupt handler routine
*/
.globl io_int_handler
io_int_handler:
stck __LC_INT_CLOCK
stpt __LC_ASYNC_ENTER_TIMER
SAVE_ALL_ASYNC __LC_IO_OLD_PSW,__LC_SAVE_AREA+40
CREATE_STACK_FRAME __LC_SAVE_AREA+40
mvc SP_PSW(16,%r15),0(%r12) # move user PSW to stack
lg %r12,__LC_THREAD_INFO # load pointer to thread_info struct
tm SP_PSW+1(%r15),0x01 # interrupting from user ?
jz 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
LAST_BREAK
io_no_vtime:
HANDLE_SIE_INTERCEPT
TRACE_IRQS_OFF
la %r2,SP_PTREGS(%r15) # address of register-save area
brasl %r14,do_IRQ # call standard irq handler
io_return:
LOCKDEP_SYS_EXIT
TRACE_IRQS_ON
io_tif:
tm __TI_flags+7(%r12),_TIF_WORK_INT
jnz io_work # there is work to do (signals etc.)
io_restore:
RESTORE_ALL __LC_RETURN_PSW,0
io_done:
#
# 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 kvm is enabled check if we need to
# modify the psw to leave SIE
# 3) 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.
#
io_work:
tm SP_PSW+1(%r15),0x01 # returning to user ?
jo io_work_user # yes -> do resched & signal
#ifdef CONFIG_PREEMPT
# check for preemptive scheduling
icm %r0,15,__TI_precount(%r12)
jnz io_restore # preemption is disabled
tm __TI_flags+7(%r12),_TIF_NEED_RESCHED
jno io_restore
# switch to kernel stack
lg %r1,SP_R15(%r15)
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
# TRACE_IRQS_ON already done at io_return, call
# TRACE_IRQS_OFF to keep things symmetrical
TRACE_IRQS_OFF
brasl %r14,preempt_schedule_irq
j io_return
#else
j io_restore
#endif
#
# Need to do work before returning to userspace, switch to kernel stack
#
io_work_user:
lg %r1,__LC_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
#
# One of the work bits is on. Find out which one.
# Checked are: _TIF_SIGPENDING, _TIF_NOTIFY_RESUME, _TIF_NEED_RESCHED
# and _TIF_MCCK_PENDING
#
io_work_tif:
tm __TI_flags+7(%r12),_TIF_MCCK_PENDING
jo io_mcck_pending
tm __TI_flags+7(%r12),_TIF_NEED_RESCHED
jo io_reschedule
tm __TI_flags+7(%r12),_TIF_SIGPENDING
jo io_sigpending
tm __TI_flags+7(%r12),_TIF_NOTIFY_RESUME
jo io_notify_resume
j io_return # beware of critical section cleanup
#
# _TIF_MCCK_PENDING is set, call handler
#
io_mcck_pending:
# TRACE_IRQS_ON already done at io_return
brasl %r14,s390_handle_mcck # TIF bit will be cleared by handler
TRACE_IRQS_OFF
j io_return
#
# _TIF_NEED_RESCHED is set, call schedule
#
io_reschedule:
# TRACE_IRQS_ON already done at io_return
stosm __SF_EMPTY(%r15),0x03 # reenable interrupts
brasl %r14,schedule # call scheduler
stnsm __SF_EMPTY(%r15),0xfc # disable I/O and ext. interrupts
TRACE_IRQS_OFF
j io_return
#
# _TIF_SIGPENDING or is set, call do_signal
#
io_sigpending:
# TRACE_IRQS_ON already done at io_return
stosm __SF_EMPTY(%r15),0x03 # reenable interrupts
la %r2,SP_PTREGS(%r15) # load pt_regs
brasl %r14,do_signal # call do_signal
stnsm __SF_EMPTY(%r15),0xfc # disable I/O and ext. interrupts
TRACE_IRQS_OFF
j io_return
#
# _TIF_NOTIFY_RESUME or is set, call do_notify_resume
#
io_notify_resume:
# TRACE_IRQS_ON already done at io_return
stosm __SF_EMPTY(%r15),0x03 # reenable interrupts
la %r2,SP_PTREGS(%r15) # load pt_regs
brasl %r14,do_notify_resume # call do_notify_resume
stnsm __SF_EMPTY(%r15),0xfc # disable I/O and ext. interrupts
TRACE_IRQS_OFF
j io_return
/*
* External interrupt handler routine
*/
.globl ext_int_handler
ext_int_handler:
stck __LC_INT_CLOCK
stpt __LC_ASYNC_ENTER_TIMER
SAVE_ALL_ASYNC __LC_EXT_OLD_PSW,__LC_SAVE_AREA+40
CREATE_STACK_FRAME __LC_SAVE_AREA+40
mvc SP_PSW(16,%r15),0(%r12) # move user PSW to stack
lg %r12,__LC_THREAD_INFO # load pointer to thread_info struct
tm SP_PSW+1(%r15),0x01 # interrupting from user ?
jz 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
LAST_BREAK
ext_no_vtime:
HANDLE_SIE_INTERCEPT
TRACE_IRQS_OFF
lghi %r1,4096
la %r2,SP_PTREGS(%r15) # address of register-save area
llgf %r3,__LC_CPU_ADDRESS # get cpu address + interruption code
llgf %r4,__LC_EXT_PARAMS # get external parameter
lg %r5,__LC_EXT_PARAMS2-4096(%r1) # get 64 bit external parameter
brasl %r14,do_extint
j io_return
__critical_end:
/*
* Machine check handler routines
*/
.globl mcck_int_handler
mcck_int_handler:
stck __LC_MCCK_CLOCK
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
stmg %r11,%r15,__LC_SAVE_AREA+80
larl %r13,system_call
lg %r11,__LC_LAST_BREAK
la %r12,__LC_MCK_OLD_PSW
tm __LC_MCCK_CODE,0x80 # system damage?
jo mcck_int_main # yes -> rest of mcck code invalid
la %r14,4095
mvc __LC_MCCK_ENTER_TIMER(8),__LC_CPU_TIMER_SAVE_AREA-4095(%r14)
tm __LC_MCCK_CODE+5,0x02 # stored cpu timer value valid?
jo 1f
la %r14,__LC_SYNC_ENTER_TIMER
clc 0(8,%r14),__LC_ASYNC_ENTER_TIMER
jl 0f
la %r14,__LC_ASYNC_ENTER_TIMER
0: clc 0(8,%r14),__LC_EXIT_TIMER
jl 0f
la %r14,__LC_EXIT_TIMER
0: clc 0(8,%r14),__LC_LAST_UPDATE_TIMER
jl 0f
la %r14,__LC_LAST_UPDATE_TIMER
0: spt 0(%r14)
mvc __LC_MCCK_ENTER_TIMER(8),0(%r14)
1: 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: aghi %r15,-SP_SIZE # make room for registers & psw
CREATE_STACK_FRAME __LC_SAVE_AREA+80
mvc SP_PSW(16,%r15),0(%r12)
lg %r12,__LC_THREAD_INFO # load pointer to thread_info struct
tm __LC_MCCK_CODE+2,0x08 # mwp of old psw valid?
jno mcck_no_vtime # no -> no timer update
tm SP_PSW+1(%r15),0x01 # interrupting from user ?
jz mcck_no_vtime
UPDATE_VTIME __LC_EXIT_TIMER,__LC_MCCK_ENTER_TIMER,__LC_USER_TIMER
UPDATE_VTIME __LC_LAST_UPDATE_TIMER,__LC_EXIT_TIMER,__LC_SYSTEM_TIMER
mvc __LC_LAST_UPDATE_TIMER(8),__LC_MCCK_ENTER_TIMER
LAST_BREAK
mcck_no_vtime:
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(%r12),_TIF_MCCK_PENDING
jno mcck_return
HANDLE_SIE_INTERCEPT
TRACE_IRQS_OFF
brasl %r14,s390_handle_mcck
TRACE_IRQS_ON
mcck_return:
mvc __LC_RETURN_MCCK_PSW(16),SP_PSW(%r15) # move return PSW
ni __LC_RETURN_MCCK_PSW+1,0xfd # clear wait state bit
lmg %r0,%r15,SP_R0(%r15) # load gprs 0-15
tm __LC_RETURN_MCCK_PSW+1,0x01 # returning to user ?
jno 0f
stpt __LC_EXIT_TIMER
0: lpswe __LC_RETURN_MCCK_PSW # back to caller
mcck_done:
/*
* Restart interruption handler, kick starter for additional CPUs
*/
#ifdef CONFIG_SMP
__CPUINIT
.globl restart_int_handler
restart_int_handler:
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)
lg %r15,__LC_SAVE_AREA+120 # load ksp
lghi %r10,__LC_CREGS_SAVE_AREA
lctlg %c0,%c15,0(%r10) # get new ctl regs
lghi %r10,__LC_AREGS_SAVE_AREA
lam %a0,%a15,0(%r10)
lmg %r6,%r15,__SF_GPRS(%r15) # load registers from clone
lg %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
stosm __SF_EMPTY(%r15),0x04 # now we can turn dat on
jg start_secondary
.align 8
restart_vtime:
.long 0x7fffffff,0xffffffff
.previous
#else
/*
* If we do not run with SMP enabled, let the new CPU crash ...
*/
.globl restart_int_handler
restart_int_handler:
basr %r1,0
restart_base:
lpswe restart_crash-restart_base(%r1)
.align 8
restart_crash:
.long 0x000a0000,0x00000000,0x00000000,0x00000000
restart_go:
#endif
.section .kprobes.text, "ax"
#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:
lg %r15,__LC_PANIC_STACK # change to panic stack
aghi %r15,-SP_SIZE
mvc SP_PSW(16,%r15),0(%r12) # move user PSW to stack
stmg %r0,%r10,SP_R0(%r15) # store gprs %r0-%r10 to kernel stack
la %r1,__LC_SAVE_AREA
chi %r12,__LC_SVC_OLD_PSW
je 0f
chi %r12,__LC_PGM_OLD_PSW
je 0f
la %r1,__LC_SAVE_AREA+40
0: mvc SP_R11(40,%r15),0(%r1) # move %r11-%r15 to stack
mvc SP_ARGS(8,%r15),__LC_LAST_BREAK
xc __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15) # clear back chain
la %r2,SP_PTREGS(%r15) # load pt_regs
jg kernel_stack_overflow
#endif
cleanup_table_system_call:
.quad system_call, sysc_do_svc
cleanup_table_sysc_tif:
.quad sysc_tif, sysc_restore
cleanup_table_sysc_restore:
.quad sysc_restore, sysc_done
cleanup_table_io_tif:
.quad io_tif, io_restore
cleanup_table_io_restore:
.quad io_restore, io_done
cleanup_critical:
clc 8(8,%r12),BASED(cleanup_table_system_call)
jl 0f
clc 8(8,%r12),BASED(cleanup_table_system_call+8)
jl cleanup_system_call
0:
clc 8(8,%r12),BASED(cleanup_table_sysc_tif)
jl 0f
clc 8(8,%r12),BASED(cleanup_table_sysc_tif+8)
jl cleanup_sysc_tif
0:
clc 8(8,%r12),BASED(cleanup_table_sysc_restore)
jl 0f
clc 8(8,%r12),BASED(cleanup_table_sysc_restore+8)
jl cleanup_sysc_restore
0:
clc 8(8,%r12),BASED(cleanup_table_io_tif)
jl 0f
clc 8(8,%r12),BASED(cleanup_table_io_tif+8)
jl cleanup_io_tif
0:
clc 8(8,%r12),BASED(cleanup_table_io_restore)
jl 0f
clc 8(8,%r12),BASED(cleanup_table_io_restore+8)
jl cleanup_io_restore
0:
br %r14
cleanup_system_call:
mvc __LC_RETURN_PSW(16),0(%r12)
clc __LC_RETURN_PSW+8(8),BASED(cleanup_system_call_insn+8)
jh 0f
mvc __LC_SYNC_ENTER_TIMER(8),__LC_MCCK_ENTER_TIMER
cghi %r12,__LC_MCK_OLD_PSW
je 0f
mvc __LC_SYNC_ENTER_TIMER(8),__LC_ASYNC_ENTER_TIMER
0: cghi %r12,__LC_MCK_OLD_PSW
la %r12,__LC_SAVE_AREA+80
je 0f
la %r12,__LC_SAVE_AREA+40
0: clc __LC_RETURN_PSW+8(8),BASED(cleanup_system_call_insn+16)
jhe cleanup_vtime
clc __LC_RETURN_PSW+8(8),BASED(cleanup_system_call_insn)
jh 0f
mvc __LC_SAVE_AREA(40),0(%r12)
0: lg %r15,__LC_KERNEL_STACK # problem state -> load ksp
aghi %r15,-SP_SIZE # make room for registers & psw
stg %r15,32(%r12)
stg %r11,0(%r12)
CREATE_STACK_FRAME __LC_SAVE_AREA
mvc SP_PSW(16,%r15),__LC_SVC_OLD_PSW
mvc SP_ILC(4,%r15),__LC_SVC_ILC
mvc 8(8,%r12),__LC_THREAD_INFO
cleanup_vtime:
clc __LC_RETURN_PSW+8(8),BASED(cleanup_system_call_insn+24)
jhe cleanup_stime
UPDATE_VTIME __LC_EXIT_TIMER,__LC_SYNC_ENTER_TIMER,__LC_USER_TIMER
cleanup_stime:
clc __LC_RETURN_PSW+8(8),BASED(cleanup_system_call_insn+32)
jh 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
srag %r12,%r11,23
lg %r12,__LC_THREAD_INFO
jz 0f
stg %r11,__TI_last_break(%r12)
0: mvc __LC_RETURN_PSW+8(8),BASED(cleanup_table_system_call+8)
la %r12,__LC_RETURN_PSW
br %r14
cleanup_system_call_insn:
.quad sysc_saveall
.quad system_call
.quad sysc_vtime
.quad sysc_stime
.quad sysc_update
cleanup_sysc_tif:
mvc __LC_RETURN_PSW(8),0(%r12)
mvc __LC_RETURN_PSW+8(8),BASED(cleanup_table_sysc_tif)
la %r12,__LC_RETURN_PSW
br %r14
cleanup_sysc_restore:
clc 8(8,%r12),BASED(cleanup_sysc_restore_insn)
je 2f
clc 8(8,%r12),BASED(cleanup_sysc_restore_insn+8)
jhe 0f
mvc __LC_EXIT_TIMER(8),__LC_MCCK_ENTER_TIMER
cghi %r12,__LC_MCK_OLD_PSW
je 0f
mvc __LC_EXIT_TIMER(8),__LC_ASYNC_ENTER_TIMER
0: mvc __LC_RETURN_PSW(16),SP_PSW(%r15)
cghi %r12,__LC_MCK_OLD_PSW
la %r12,__LC_SAVE_AREA+80
je 1f
la %r12,__LC_SAVE_AREA+40
1: mvc 0(40,%r12),SP_R11(%r15)
lmg %r0,%r10,SP_R0(%r15)
lg %r15,SP_R15(%r15)
2: la %r12,__LC_RETURN_PSW
br %r14
cleanup_sysc_restore_insn:
.quad sysc_done - 4
.quad sysc_done - 16
cleanup_io_tif:
mvc __LC_RETURN_PSW(8),0(%r12)
mvc __LC_RETURN_PSW+8(8),BASED(cleanup_table_io_tif)
la %r12,__LC_RETURN_PSW
br %r14
cleanup_io_restore:
clc 8(8,%r12),BASED(cleanup_io_restore_insn)
je 1f
clc 8(8,%r12),BASED(cleanup_io_restore_insn+8)
jhe 0f
mvc __LC_EXIT_TIMER(8),__LC_MCCK_ENTER_TIMER
0: mvc __LC_RETURN_PSW(16),SP_PSW(%r15)
mvc __LC_SAVE_AREA+80(40),SP_R11(%r15)
lmg %r0,%r10,SP_R0(%r15)
lg %r15,SP_R15(%r15)
1: la %r12,__LC_RETURN_PSW
br %r14
cleanup_io_restore_insn:
.quad io_done - 4
.quad io_done - 16
/*
* Integer constants
*/
.align 4
.Lcritical_start:
.quad __critical_start
.Lcritical_end:
.quad __critical_end
.section .rodata, "a"
#define SYSCALL(esa,esame,emu) .long esame
.globl sys_call_table
sys_call_table:
#include "syscalls.S"
#undef SYSCALL
#ifdef CONFIG_COMPAT
#define SYSCALL(esa,esame,emu) .long emu
sys_call_table_emu:
#include "syscalls.S"
#undef SYSCALL
#endif
