/* * arch/s390/kernel/entry64.S * S390 low-level entry points. * * Copyright (C) IBM Corp. 1999,2006 * 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 */ #include #include #include #include #include #include #include #include #include /* * 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_SINGLE_STEP ) _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) #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 .macro TRACE_IRQS_CHECK basr %r2,%r0 tm SP_PSW(%r15),0x03 # irqs enabled? jz 0f brasl %r14,trace_hardirqs_on_caller j 1f 0: brasl %r14,trace_hardirqs_off_caller 1: .endm #else #define TRACE_IRQS_ON #define TRACE_IRQS_OFF #define TRACE_IRQS_CHECK #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_BASE savearea stmg %r12,%r15,\savearea larl %r13,system_call .endm .macro SAVE_ALL_SVC psworg,savearea la %r12,\psworg lg %r15,__LC_KERNEL_STACK # problem state -> load ksp .endm .macro SAVE_ALL_SYNC psworg,savearea la %r12,\psworg tm \psworg+1,0x01 # test problem state bit jz 2f # skip stack setup save lg %r15,__LC_KERNEL_STACK # problem state -> load ksp #ifdef CONFIG_CHECK_STACK j 3f 2: tml %r15,STACK_SIZE - CONFIG_STACK_GUARD jz stack_overflow 3: #endif 2: .endm .macro SAVE_ALL_ASYNC psworg,savearea 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 jz 2f 1: lg %r15,__LC_ASYNC_STACK # load async stack #ifdef CONFIG_CHECK_STACK j 3f 2: tml %r15,STACK_SIZE - CONFIG_STACK_GUARD jz stack_overflow 3: #endif 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 stg %r2,SP_ORIG_R2(%r15) # store original content of gpr 2 icm %r12,3,__LC_SVC_ILC stmg %r0,%r11,SP_R0(%r15) # store gprs %r0-%r11 to kernel stack st %r12,SP_SVCNR(%r15) mvc SP_R12(32,%r15),\savearea # move %r12-%r15 to stack la %r12,0 stg %r12,__SF_BACKCHAIN(%r15) .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 /* * Scheduler resume function, called by switch_to * gpr2 = (task_struct *) prev * gpr3 = (task_struct *) next * Returns: * gpr2 = prev */ .globl __switch_to __switch_to: tm __THREAD_per+4(%r3),0xe8 # is the new process using per ? jz __switch_to_noper # if not we're fine stctg %c9,%c11,__SF_EMPTY(%r15)# We are using per stuff clc __THREAD_per(24,%r3),__SF_EMPTY(%r15) 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 lmg %r6,%r15,__SF_GPRS(%r15)# load __switch_to registers of next task stg %r3,__LC_CURRENT # __LC_CURRENT = current task struct lctl %c4,%c4,__TASK_pid(%r3) # load pid to control reg. 4 lg %r3,__THREAD_info(%r3) # load thread_info from task struct stg %r3,__LC_THREAD_INFO aghi %r3,STACK_SIZE stg %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. */ .globl system_call system_call: stpt __LC_SYNC_ENTER_TIMER sysc_saveall: SAVE_ALL_BASE __LC_SAVE_AREA SAVE_ALL_SVC __LC_SVC_OLD_PSW,__LC_SAVE_AREA CREATE_STACK_FRAME __LC_SVC_OLD_PSW,__LC_SAVE_AREA llgh %r7,__LC_SVC_INT_CODE # 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: lg %r9,__LC_THREAD_INFO # load pointer to thread_info struct ltgr %r7,%r7 # test for svc 0 jnz sysc_nr_ok # svc 0: system call number in %r1 cl %r1,BASED(.Lnr_syscalls) jnl sysc_nr_ok lgfr %r7,%r1 # clear high word in r1 sysc_nr_ok: mvc SP_ARGS(8,%r15),SP_R7(%r15) sysc_do_restart: sth %r7,SP_SVCNR(%r15) sllg %r7,%r7,2 # svc number * 4 larl %r10,sys_call_table #ifdef CONFIG_COMPAT tm __TI_flags+5(%r9),(_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(%r9),_TIF_SYSCALL 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: tm __TI_flags+7(%r9),_TIF_WORK_SVC jnz sysc_work # there is work to do (signals etc.) sysc_restore: #ifdef CONFIG_TRACE_IRQFLAGS larl %r1,sysc_restore_trace_psw lpswe 0(%r1) sysc_restore_trace: TRACE_IRQS_CHECK LOCKDEP_SYS_EXIT #endif sysc_leave: RESTORE_ALL __LC_RETURN_PSW,1 sysc_done: #ifdef CONFIG_TRACE_IRQFLAGS .section .data,"aw",@progbits .align 8 .globl sysc_restore_trace_psw sysc_restore_trace_psw: .quad 0, sysc_restore_trace .previous #endif # # 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_loop: 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 jo sysc_sigpending tm __TI_flags+7(%r9),_TIF_NOTIFY_RESUME jo sysc_notify_resume tm __TI_flags+7(%r9),_TIF_RESTART_SVC jo sysc_restart tm __TI_flags+7(%r9),_TIF_SINGLE_STEP jo sysc_singlestep j sysc_return # beware of critical section cleanup # # _TIF_NEED_RESCHED is set, call schedule # sysc_reschedule: larl %r14,sysc_work_loop jg schedule # return point is sysc_work_loop # # _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 # sysc_sigpending: ni __TI_flags+7(%r9),255-_TIF_SINGLE_STEP # clear TIF_SINGLE_STEP la %r2,SP_PTREGS(%r15) # load pt_regs brasl %r14,do_signal # call do_signal tm __TI_flags+7(%r9),_TIF_RESTART_SVC jo sysc_restart tm __TI_flags+7(%r9),_TIF_SINGLE_STEP jo sysc_singlestep j sysc_work_loop # # _TIF_NOTIFY_RESUME is set, call do_notify_resume # sysc_notify_resume: la %r2,SP_PTREGS(%r15) # load pt_regs larl %r14,sysc_work_loop 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(%r9),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 j sysc_do_restart # restart svc # # _TIF_SINGLE_STEP is set, call do_single_step # sysc_singlestep: ni __TI_flags+7(%r9),255-_TIF_SINGLE_STEP # clear TIF_SINGLE_STEP xc SP_SVCNR(2,%r15),SP_SVCNR(%r15) # clear svc number la %r2,SP_PTREGS(%r15) # address of register-save area larl %r14,sysc_work_loop # load adr. of system return jg do_single_step # branch to do_sigtrap # # 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 srl %r7,2 stg %r7,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) 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(%r9),_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 %r9,__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 lg %r9,__LC_THREAD_INFO mvc SP_PTREGS(__PT_SIZE,%r15),0(%r12) # copy pt_regs 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 SAVE_ALL_BASE __LC_SAVE_AREA tm __LC_PGM_INT_CODE+1,0x80 # check whether we got a per exception jnz pgm_per # got per exception -> special case SAVE_ALL_SYNC __LC_PGM_OLD_PSW,__LC_SAVE_AREA CREATE_STACK_FRAME __LC_PGM_OLD_PSW,__LC_SAVE_AREA 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 pgm_no_vtime: lg %r9,__LC_THREAD_INFO # load pointer to thread_info struct mvc SP_ARGS(8,%r15),__LC_LAST_BREAK TRACE_IRQS_OFF lgf %r3,__LC_PGM_ILC # load program interruption code lghi %r8,0x7f ngr %r8,%r3 pgm_do_call: 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 larl %r14,sysc_return br %r1 # branch to interrupt-handler # # 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 lmg %r12,%r15,__LC_SAVE_AREA lpswe __LC_PGM_OLD_PSW # # Normal per exception # pgm_per_std: SAVE_ALL_SYNC __LC_PGM_OLD_PSW,__LC_SAVE_AREA CREATE_STACK_FRAME __LC_PGM_OLD_PSW,__LC_SAVE_AREA 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 pgm_no_vtime2: lg %r9,__LC_THREAD_INFO # load pointer to thread_info struct TRACE_IRQS_OFF lg %r1,__TI_task(%r9) tm SP_PSW+1(%r15),0x01 # kernel per event ? jz kernel_per mvc __THREAD_per+__PER_atmid(2,%r1),__LC_PER_ATMID mvc __THREAD_per+__PER_address(8,%r1),__LC_PER_ADDRESS mvc __THREAD_per+__PER_access_id(1,%r1),__LC_PER_ACCESS_ID oi __TI_flags+7(%r9),_TIF_SINGLE_STEP # set TIF_SINGLE_STEP lgf %r3,__LC_PGM_ILC # load program interruption code lghi %r8,0x7f ngr %r8,%r3 # clear per-event-bit and ilc je sysc_return j pgm_do_call # # it was a single stepped SVC that is causing all the trouble # pgm_svcper: SAVE_ALL_SYNC __LC_SVC_OLD_PSW,__LC_SAVE_AREA CREATE_STACK_FRAME __LC_SVC_OLD_PSW,__LC_SAVE_AREA 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 llgh %r7,__LC_SVC_INT_CODE # get svc number from lowcore lg %r9,__LC_THREAD_INFO # load pointer to thread_info struct lg %r8,__TI_task(%r9) mvc __THREAD_per+__PER_atmid(2,%r8),__LC_PER_ATMID mvc __THREAD_per+__PER_address(8,%r8),__LC_PER_ADDRESS mvc __THREAD_per+__PER_access_id(1,%r8),__LC_PER_ACCESS_ID oi __TI_flags+7(%r9),_TIF_SINGLE_STEP # set TIF_SINGLE_STEP TRACE_IRQS_ON lmg %r2,%r6,SP_R2(%r15) # load svc arguments stosm __SF_EMPTY(%r15),0x03 # reenable interrupts j sysc_do_svc # # per was called from kernel, must be kprobes # kernel_per: xc SP_SVCNR(2,%r15),SP_SVCNR(%r15) # clear svc number la %r2,SP_PTREGS(%r15) # address of register-save area larl %r14,sysc_restore # load adr. of system ret, no work jg do_single_step # branch to do_single_step /* * IO interrupt handler routine */ .globl io_int_handler io_int_handler: stck __LC_INT_CLOCK stpt __LC_ASYNC_ENTER_TIMER SAVE_ALL_BASE __LC_SAVE_AREA+32 SAVE_ALL_ASYNC __LC_IO_OLD_PSW,__LC_SAVE_AREA+32 CREATE_STACK_FRAME __LC_IO_OLD_PSW,__LC_SAVE_AREA+32 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 io_no_vtime: lg %r9,__LC_THREAD_INFO # load pointer to thread_info struct TRACE_IRQS_OFF la %r2,SP_PTREGS(%r15) # address of register-save area brasl %r14,do_IRQ # call standard irq handler io_return: tm __TI_flags+7(%r9),_TIF_WORK_INT jnz io_work # there is work to do (signals etc.) io_restore: #ifdef CONFIG_TRACE_IRQFLAGS larl %r1,io_restore_trace_psw lpswe 0(%r1) io_restore_trace: TRACE_IRQS_CHECK LOCKDEP_SYS_EXIT #endif io_leave: RESTORE_ALL __LC_RETURN_PSW,0 io_done: #ifdef CONFIG_TRACE_IRQFLAGS .section .data,"aw",@progbits .align 8 .globl io_restore_trace_psw io_restore_trace_psw: .quad 0, io_restore_trace .previous #endif # # 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 #if defined(CONFIG_KVM) || defined(CONFIG_KVM_MODULE) lg %r2,SP_PSW+8(%r15) # check if current instruction is SIE lh %r1,0(%r2) chi %r1,-19948 # signed 16 bit compare with 0xb214 jne 0f # no -> leave PSW alone aghi %r2,4 # yes-> add 4 bytes to leave SIE stg %r2,SP_PSW+8(%r15) 0: #endif #ifdef CONFIG_PREEMPT # check for preemptive scheduling icm %r0,15,__TI_precount(%r9) jnz io_restore # preemption is disabled # 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 io_resume_loop: larl %r14,io_resume_loop tm __TI_flags+7(%r12),_TIF_NEED_RESCHED jgo preempt_schedule_irq #endif j io_restore # # 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_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 tm __TI_flags+7(%r9),_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: brasl %r14,s390_handle_mcck # TIF bit will be cleared by handler j io_work_loop # # _TIF_NEED_RESCHED is set, call schedule # io_reschedule: TRACE_IRQS_ON 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_work_loop # # _TIF_SIGPENDING or is set, call do_signal # io_sigpending: TRACE_IRQS_ON 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_work_loop # # _TIF_NOTIFY_RESUME or is set, call do_notify_resume # io_notify_resume: TRACE_IRQS_ON 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_work_loop /* * External interrupt handler routine */ .globl ext_int_handler ext_int_handler: stck __LC_INT_CLOCK stpt __LC_ASYNC_ENTER_TIMER SAVE_ALL_BASE __LC_SAVE_AREA+32 SAVE_ALL_ASYNC __LC_EXT_OLD_PSW,__LC_SAVE_AREA+32 CREATE_STACK_FRAME __LC_EXT_OLD_PSW,__LC_SAVE_AREA+32 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 ext_no_vtime: lg %r9,__LC_THREAD_INFO # load pointer to thread_info struct TRACE_IRQS_OFF la %r2,SP_PTREGS(%r15) # address of register-save area llgh %r3,__LC_EXT_INT_CODE # get interruption code brasl %r14,do_extint j io_return __critical_end: /* * Machine check handler routines */ .globl mcck_int_handler mcck_int_handler: stck __LC_INT_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 SAVE_ALL_BASE __LC_SAVE_AREA+64 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_SAVE_AREA+104(8),__LC_ASYNC_ENTER_TIMER mvc __LC_ASYNC_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_ASYNC_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: CREATE_STACK_FRAME __LC_MCK_OLD_PSW,__LC_SAVE_AREA+64 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_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: 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 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 mvc __LC_ASYNC_ENTER_TIMER(8),__LC_SAVE_AREA+104 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 /* * 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 #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,%r11,SP_R0(%r15) # store gprs %r0-%r11 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+32 0: mvc SP_R12(32,%r15),0(%r1) # move %r12-%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_return: .quad sysc_return, sysc_leave cleanup_table_sysc_leave: .quad sysc_leave, sysc_done cleanup_table_io_return: .quad io_return, io_leave cleanup_table_io_leave: .quad io_leave, 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_return) jl 0f clc 8(8,%r12),BASED(cleanup_table_sysc_return+8) jl cleanup_sysc_return 0: clc 8(8,%r12),BASED(cleanup_table_sysc_leave) jl 0f clc 8(8,%r12),BASED(cleanup_table_sysc_leave+8) jl cleanup_sysc_leave 0: clc 8(8,%r12),BASED(cleanup_table_io_return) jl 0f clc 8(8,%r12),BASED(cleanup_table_io_return+8) jl cleanup_io_return 0: clc 8(8,%r12),BASED(cleanup_table_io_leave) jl 0f clc 8(8,%r12),BASED(cleanup_table_io_leave+8) jl cleanup_io_leave 0: br %r14 cleanup_system_call: mvc __LC_RETURN_PSW(16),0(%r12) cghi %r12,__LC_MCK_OLD_PSW je 0f la %r12,__LC_SAVE_AREA+32 j 1f 0: la %r12,__LC_SAVE_AREA+64 1: clc __LC_RETURN_PSW+8(8),BASED(cleanup_system_call_insn+8) jh 0f mvc __LC_SYNC_ENTER_TIMER(8),__LC_ASYNC_ENTER_TIMER 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(32),0(%r12) 0: stg %r13,8(%r12) stg %r12,__LC_SAVE_AREA+96 # argh SAVE_ALL_SYNC __LC_SVC_OLD_PSW,__LC_SAVE_AREA CREATE_STACK_FRAME __LC_SVC_OLD_PSW,__LC_SAVE_AREA lg %r12,__LC_SAVE_AREA+96 # argh stg %r15,24(%r12) llgh %r7,__LC_SVC_INT_CODE 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 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_return: mvc __LC_RETURN_PSW(8),0(%r12) mvc __LC_RETURN_PSW+8(8),BASED(cleanup_table_sysc_return) la %r12,__LC_RETURN_PSW br %r14 cleanup_sysc_leave: clc 8(8,%r12),BASED(cleanup_sysc_leave_insn) je 3f clc 8(8,%r12),BASED(cleanup_sysc_leave_insn+8) jhe 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 jne 1f mvc __LC_SAVE_AREA+64(32),SP_R12(%r15) j 2f 1: mvc __LC_SAVE_AREA+32(32),SP_R12(%r15) 2: lmg %r0,%r11,SP_R0(%r15) lg %r15,SP_R15(%r15) 3: la %r12,__LC_RETURN_PSW br %r14 cleanup_sysc_leave_insn: .quad sysc_done - 4 .quad sysc_done - 16 cleanup_io_return: mvc __LC_RETURN_PSW(8),0(%r12) mvc __LC_RETURN_PSW+8(8),BASED(cleanup_table_io_return) la %r12,__LC_RETURN_PSW br %r14 cleanup_io_leave: clc 8(8,%r12),BASED(cleanup_io_leave_insn) je 3f clc 8(8,%r12),BASED(cleanup_io_leave_insn+8) jhe 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 jne 1f mvc __LC_SAVE_AREA+64(32),SP_R12(%r15) j 2f 1: mvc __LC_SAVE_AREA+32(32),SP_R12(%r15) 2: lmg %r0,%r11,SP_R0(%r15) lg %r15,SP_R15(%r15) 3: la %r12,__LC_RETURN_PSW br %r14 cleanup_io_leave_insn: .quad io_done - 4 .quad io_done - 16 /* * Integer constants */ .align 4 .Lconst: .Lnr_syscalls: .long NR_syscalls .L0x0130: .short 0x130 .L0x0140: .short 0x140 .L0x0150: .short 0x150 .L0x0160: .short 0x160 .L0x0170: .short 0x170 .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