2 * arch/s390/kernel/entry.S
3 * S390 low-level entry points.
5 * Copyright (C) IBM Corp. 1999,2006
6 * Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
7 * Hartmut Penner (hp@de.ibm.com),
8 * Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com),
9 * Heiko Carstens <heiko.carstens@de.ibm.com>
12 #include <linux/linkage.h>
13 #include <linux/init.h>
14 #include <asm/cache.h>
15 #include <asm/errno.h>
16 #include <asm/ptrace.h>
17 #include <asm/thread_info.h>
18 #include <asm/asm-offsets.h>
19 #include <asm/unistd.h>
23 * Stack layout for the system_call stack entry.
24 * The first few entries are identical to the user_regs_struct.
26 SP_PTREGS = STACK_FRAME_OVERHEAD
27 SP_ARGS = STACK_FRAME_OVERHEAD + __PT_ARGS
28 SP_PSW = STACK_FRAME_OVERHEAD + __PT_PSW
29 SP_R0 = STACK_FRAME_OVERHEAD + __PT_GPRS
30 SP_R1 = STACK_FRAME_OVERHEAD + __PT_GPRS + 4
31 SP_R2 = STACK_FRAME_OVERHEAD + __PT_GPRS + 8
32 SP_R3 = STACK_FRAME_OVERHEAD + __PT_GPRS + 12
33 SP_R4 = STACK_FRAME_OVERHEAD + __PT_GPRS + 16
34 SP_R5 = STACK_FRAME_OVERHEAD + __PT_GPRS + 20
35 SP_R6 = STACK_FRAME_OVERHEAD + __PT_GPRS + 24
36 SP_R7 = STACK_FRAME_OVERHEAD + __PT_GPRS + 28
37 SP_R8 = STACK_FRAME_OVERHEAD + __PT_GPRS + 32
38 SP_R9 = STACK_FRAME_OVERHEAD + __PT_GPRS + 36
39 SP_R10 = STACK_FRAME_OVERHEAD + __PT_GPRS + 40
40 SP_R11 = STACK_FRAME_OVERHEAD + __PT_GPRS + 44
41 SP_R12 = STACK_FRAME_OVERHEAD + __PT_GPRS + 48
42 SP_R13 = STACK_FRAME_OVERHEAD + __PT_GPRS + 52
43 SP_R14 = STACK_FRAME_OVERHEAD + __PT_GPRS + 56
44 SP_R15 = STACK_FRAME_OVERHEAD + __PT_GPRS + 60
45 SP_ORIG_R2 = STACK_FRAME_OVERHEAD + __PT_ORIG_GPR2
46 SP_ILC = STACK_FRAME_OVERHEAD + __PT_ILC
47 SP_SVCNR = STACK_FRAME_OVERHEAD + __PT_SVCNR
48 SP_SIZE = STACK_FRAME_OVERHEAD + __PT_SIZE
50 _TIF_WORK_SVC = (_TIF_SIGPENDING | _TIF_NOTIFY_RESUME | _TIF_NEED_RESCHED | \
51 _TIF_MCCK_PENDING | _TIF_RESTART_SVC | _TIF_PER_TRAP )
52 _TIF_WORK_INT = (_TIF_SIGPENDING | _TIF_NOTIFY_RESUME | _TIF_NEED_RESCHED | \
54 _TIF_SYSCALL = (_TIF_SYSCALL_TRACE>>8 | _TIF_SYSCALL_AUDIT>>8 | \
55 _TIF_SECCOMP>>8 | _TIF_SYSCALL_TRACEPOINT>>8)
57 STACK_SHIFT = PAGE_SHIFT + THREAD_ORDER
58 STACK_SIZE = 1 << STACK_SHIFT
60 #define BASED(name) name-system_call(%r13)
62 #ifdef CONFIG_TRACE_IRQFLAGS
65 l %r1,BASED(.Ltrace_irq_on_caller)
71 l %r1,BASED(.Ltrace_irq_off_caller)
76 #define TRACE_IRQS_OFF
80 .macro LOCKDEP_SYS_EXIT
81 tm SP_PSW+1(%r15),0x01 # returning to user ?
83 l %r1,BASED(.Llockdep_sys_exit)
88 #define LOCKDEP_SYS_EXIT
92 * Register usage in interrupt handlers:
93 * R9 - pointer to current task structure
94 * R13 - pointer to literal pool
95 * R14 - return register for function calls
96 * R15 - kernel stack pointer
99 .macro UPDATE_VTIME lc_from,lc_to,lc_sum
100 lm %r10,%r11,\lc_from
109 1: stm %r10,%r11,\lc_sum
112 .macro SAVE_ALL_SVC psworg,savearea
113 stm %r12,%r15,\savearea
114 l %r13,__LC_SVC_NEW_PSW+4 # load &system_call to %r13
115 l %r15,__LC_KERNEL_STACK # problem state -> load ksp
116 s %r15,BASED(.Lc_spsize) # make room for registers & psw
119 .macro SAVE_ALL_BASE savearea
120 stm %r12,%r15,\savearea
121 l %r13,__LC_SVC_NEW_PSW+4 # load &system_call to %r13
124 .macro SAVE_ALL_PGM psworg,savearea
125 tm \psworg+1,0x01 # test problem state bit
126 #ifdef CONFIG_CHECK_STACK
128 tml %r15,STACK_SIZE - CONFIG_STACK_GUARD
131 b BASED(stack_overflow)
135 1: l %r15,__LC_KERNEL_STACK # problem state -> load ksp
136 2: s %r15,BASED(.Lc_spsize) # make room for registers & psw
139 .macro SAVE_ALL_ASYNC psworg,savearea
140 stm %r12,%r15,\savearea
141 l %r13,__LC_SVC_NEW_PSW+4 # load &system_call to %r13
143 tm \psworg+1,0x01 # test problem state bit
144 bnz BASED(1f) # from user -> load async stack
145 clc \psworg+4(4),BASED(.Lcritical_end)
147 clc \psworg+4(4),BASED(.Lcritical_start)
149 l %r14,BASED(.Lcleanup_critical)
151 tm 1(%r12),0x01 # retest problem state after cleanup
153 0: l %r14,__LC_ASYNC_STACK # are we already on the async stack ?
156 #ifdef CONFIG_CHECK_STACK
158 tml %r15,STACK_SIZE - CONFIG_STACK_GUARD
160 b BASED(stack_overflow)
164 1: l %r15,__LC_ASYNC_STACK
165 2: s %r15,BASED(.Lc_spsize) # make room for registers & psw
168 .macro CREATE_STACK_FRAME savearea
169 xc __SF_BACKCHAIN(4,%r15),__SF_BACKCHAIN(%r15)
170 st %r2,SP_ORIG_R2(%r15) # store original content of gpr 2
171 mvc SP_R12(16,%r15),\savearea # move %r12-%r15 to stack
172 stm %r0,%r11,SP_R0(%r15) # store gprs %r0-%r11 to kernel stack
175 .macro RESTORE_ALL psworg,sync
176 mvc \psworg(8),SP_PSW(%r15) # move user PSW to lowcore
178 ni \psworg+1,0xfd # clear wait state bit
180 lm %r0,%r15,SP_R0(%r15) # load gprs 0-15 of user
182 lpsw \psworg # back to caller
186 mvc __SF_EMPTY(1,%r15),SP_PSW(%r15)
187 ni __SF_EMPTY(%r15),0xbf
191 .section .kprobes.text, "ax"
194 * Scheduler resume function, called by switch_to
195 * gpr2 = (task_struct *) prev
196 * gpr3 = (task_struct *) next
203 0: l %r4,__THREAD_info(%r2) # get thread_info of prev
204 l %r5,__THREAD_info(%r3) # get thread_info of next
205 tm __TI_flags+3(%r4),_TIF_MCCK_PENDING # machine check pending?
207 ni __TI_flags+3(%r4),255-_TIF_MCCK_PENDING # clear flag in prev
208 oi __TI_flags+3(%r5),_TIF_MCCK_PENDING # set it in next
209 1: stm %r6,%r15,__SF_GPRS(%r15) # store gprs of prev task
210 st %r15,__THREAD_ksp(%r2) # store kernel stack of prev
211 l %r15,__THREAD_ksp(%r3) # load kernel stack of next
212 lctl %c4,%c4,__TASK_pid(%r3) # load pid to control reg. 4
213 lm %r6,%r15,__SF_GPRS(%r15) # load gprs of next task
214 st %r3,__LC_CURRENT # store task struct of next
215 mvc __LC_CURRENT_PID(4,%r0),__TASK_pid(%r3) # store pid of next
216 st %r5,__LC_THREAD_INFO # store thread info of next
217 ahi %r5,STACK_SIZE # end of kernel stack of next
218 st %r5,__LC_KERNEL_STACK # store end of kernel stack
223 * SVC interrupt handler routine. System calls are synchronous events and
224 * are executed with interrupts enabled.
229 stpt __LC_SYNC_ENTER_TIMER
231 SAVE_ALL_SVC __LC_SVC_OLD_PSW,__LC_SAVE_AREA
232 CREATE_STACK_FRAME __LC_SAVE_AREA
233 mvc SP_PSW(8,%r15),__LC_SVC_OLD_PSW
234 mvc SP_ILC(4,%r15),__LC_SVC_ILC
235 l %r12,__LC_THREAD_INFO # load pointer to thread_info struct
237 UPDATE_VTIME __LC_EXIT_TIMER,__LC_SYNC_ENTER_TIMER,__LC_USER_TIMER
239 UPDATE_VTIME __LC_LAST_UPDATE_TIMER,__LC_EXIT_TIMER,__LC_SYSTEM_TIMER
241 mvc __LC_LAST_UPDATE_TIMER(8),__LC_SYNC_ENTER_TIMER
244 icm %r7,3,SP_SVCNR(%r15) # load svc number and test for svc 0
245 bnz BASED(sysc_nr_ok) # svc number > 0
246 # svc 0: system call number in %r1
247 cl %r1,BASED(.Lnr_syscalls)
248 bnl BASED(sysc_nr_ok)
249 sth %r1,SP_SVCNR(%r15)
250 lr %r7,%r1 # copy svc number to %r7
252 sll %r7,2 # svc number *4
253 l %r10,BASED(.Lsysc_table)
254 tm __TI_flags+2(%r12),_TIF_SYSCALL
255 mvc SP_ARGS(4,%r15),SP_R7(%r15)
256 l %r8,0(%r7,%r10) # get system call addr.
257 bnz BASED(sysc_tracesys)
258 basr %r14,%r8 # call sys_xxxx
259 st %r2,SP_R2(%r15) # store return value (change R2 on stack)
264 tm __TI_flags+3(%r12),_TIF_WORK_SVC
265 bnz BASED(sysc_work) # there is work to do (signals etc.)
267 RESTORE_ALL __LC_RETURN_PSW,1
271 # There is work to do, but first we need to check if we return to userspace.
274 tm SP_PSW+1(%r15),0x01 # returning to user ?
275 bno BASED(sysc_restore)
278 # One of the work bits is on. Find out which one.
281 tm __TI_flags+3(%r12),_TIF_MCCK_PENDING
282 bo BASED(sysc_mcck_pending)
283 tm __TI_flags+3(%r12),_TIF_NEED_RESCHED
284 bo BASED(sysc_reschedule)
285 tm __TI_flags+3(%r12),_TIF_SIGPENDING
286 bo BASED(sysc_sigpending)
287 tm __TI_flags+3(%r12),_TIF_NOTIFY_RESUME
288 bo BASED(sysc_notify_resume)
289 tm __TI_flags+3(%r12),_TIF_RESTART_SVC
290 bo BASED(sysc_restart)
291 tm __TI_flags+3(%r12),_TIF_PER_TRAP
292 bo BASED(sysc_singlestep)
293 b BASED(sysc_return) # beware of critical section cleanup
296 # _TIF_NEED_RESCHED is set, call schedule
299 l %r1,BASED(.Lschedule)
300 la %r14,BASED(sysc_return)
301 br %r1 # call scheduler
304 # _TIF_MCCK_PENDING is set, call handler
307 l %r1,BASED(.Ls390_handle_mcck)
308 la %r14,BASED(sysc_return)
309 br %r1 # TIF bit will be cleared by handler
312 # _TIF_SIGPENDING is set, call do_signal
315 ni __TI_flags+3(%r12),255-_TIF_PER_TRAP # clear TIF_PER_TRAP
316 la %r2,SP_PTREGS(%r15) # load pt_regs
317 l %r1,BASED(.Ldo_signal)
318 basr %r14,%r1 # call do_signal
319 tm __TI_flags+3(%r12),_TIF_RESTART_SVC
320 bo BASED(sysc_restart)
321 tm __TI_flags+3(%r12),_TIF_PER_TRAP
322 bo BASED(sysc_singlestep)
326 # _TIF_NOTIFY_RESUME is set, call do_notify_resume
329 la %r2,SP_PTREGS(%r15) # load pt_regs
330 l %r1,BASED(.Ldo_notify_resume)
331 la %r14,BASED(sysc_return)
332 br %r1 # call do_notify_resume
336 # _TIF_RESTART_SVC is set, set up registers and restart svc
339 ni __TI_flags+3(%r12),255-_TIF_RESTART_SVC # clear TIF_RESTART_SVC
340 l %r7,SP_R2(%r15) # load new svc number
341 mvc SP_R2(4,%r15),SP_ORIG_R2(%r15) # restore first argument
342 lm %r2,%r6,SP_R2(%r15) # load svc arguments
343 sth %r7,SP_SVCNR(%r15)
344 b BASED(sysc_nr_ok) # restart svc
347 # _TIF_PER_TRAP is set, call do_per_trap
350 ni __TI_flags+3(%r12),255-_TIF_PER_TRAP # clear TIF_PER_TRAP
351 xc SP_SVCNR(2,%r15),SP_SVCNR(%r15) # clear svc number
352 la %r2,SP_PTREGS(%r15) # address of register-save area
353 l %r1,BASED(.Lhandle_per) # load adr. of per handler
354 la %r14,BASED(sysc_return) # load adr. of system return
355 br %r1 # branch to do_per_trap
358 # call tracehook_report_syscall_entry/tracehook_report_syscall_exit before
359 # and after the system call
362 l %r1,BASED(.Ltrace_entry)
363 la %r2,SP_PTREGS(%r15) # load pt_regs
366 icm %r0,3,SP_SVCNR(%r15)
369 cl %r2,BASED(.Lnr_syscalls)
370 bnl BASED(sysc_tracenogo)
372 sll %r7,2 # svc number *4
375 lm %r3,%r6,SP_R3(%r15)
376 mvc SP_ARGS(4,%r15),SP_R7(%r15)
377 l %r2,SP_ORIG_R2(%r15)
378 basr %r14,%r8 # call sys_xxx
379 st %r2,SP_R2(%r15) # store return value
381 tm __TI_flags+2(%r12),_TIF_SYSCALL
382 bz BASED(sysc_return)
383 l %r1,BASED(.Ltrace_exit)
384 la %r2,SP_PTREGS(%r15) # load pt_regs
385 la %r14,BASED(sysc_return)
389 # a new process exits the kernel with ret_from_fork
393 l %r13,__LC_SVC_NEW_PSW+4
394 l %r12,__LC_THREAD_INFO # load pointer to thread_info struct
395 tm SP_PSW+1(%r15),0x01 # forking a kernel thread ?
397 st %r15,SP_R15(%r15) # store stack pointer for new kthread
398 0: l %r1,BASED(.Lschedtail)
401 stosm __SF_EMPTY(%r15),0x03 # reenable interrupts
402 b BASED(sysc_tracenogo)
405 # kernel_execve function needs to deal with pt_regs that is not
410 stm %r12,%r15,48(%r15)
412 l %r13,__LC_SVC_NEW_PSW+4
413 s %r15,BASED(.Lc_spsize)
414 st %r14,__SF_BACKCHAIN(%r15)
415 la %r12,SP_PTREGS(%r15)
416 xc 0(__PT_SIZE,%r12),0(%r12)
417 l %r1,BASED(.Ldo_execve)
422 a %r15,BASED(.Lc_spsize)
423 lm %r12,%r15,48(%r15)
426 0: stnsm __SF_EMPTY(%r15),0xfc # disable interrupts
427 l %r15,__LC_KERNEL_STACK # load ksp
428 s %r15,BASED(.Lc_spsize) # make room for registers & psw
429 mvc SP_PTREGS(__PT_SIZE,%r15),0(%r12) # copy pt_regs
430 l %r12,__LC_THREAD_INFO
431 xc __SF_BACKCHAIN(4,%r15),__SF_BACKCHAIN(%r15)
432 stosm __SF_EMPTY(%r15),0x03 # reenable interrupts
433 l %r1,BASED(.Lexecve_tail)
438 * Program check handler routine
441 .globl pgm_check_handler
444 * First we need to check for a special case:
445 * Single stepping an instruction that disables the PER event mask will
446 * cause a PER event AFTER the mask has been set. Example: SVC or LPSW.
447 * For a single stepped SVC the program check handler gets control after
448 * the SVC new PSW has been loaded. But we want to execute the SVC first and
449 * then handle the PER event. Therefore we update the SVC old PSW to point
450 * to the pgm_check_handler and branch to the SVC handler after we checked
451 * if we have to load the kernel stack register.
452 * For every other possible cause for PER event without the PER mask set
453 * we just ignore the PER event (FIXME: is there anything we have to do
456 stpt __LC_SYNC_ENTER_TIMER
457 SAVE_ALL_BASE __LC_SAVE_AREA
458 tm __LC_PGM_INT_CODE+1,0x80 # check whether we got a per exception
459 bnz BASED(pgm_per) # got per exception -> special case
460 SAVE_ALL_PGM __LC_PGM_OLD_PSW,__LC_SAVE_AREA
461 CREATE_STACK_FRAME __LC_SAVE_AREA
462 xc SP_ILC(4,%r15),SP_ILC(%r15)
463 mvc SP_PSW(8,%r15),__LC_PGM_OLD_PSW
464 l %r12,__LC_THREAD_INFO # load pointer to thread_info struct
465 tm SP_PSW+1(%r15),0x01 # interrupting from user ?
466 bz BASED(pgm_no_vtime)
467 UPDATE_VTIME __LC_EXIT_TIMER,__LC_SYNC_ENTER_TIMER,__LC_USER_TIMER
468 UPDATE_VTIME __LC_LAST_UPDATE_TIMER,__LC_EXIT_TIMER,__LC_SYSTEM_TIMER
469 mvc __LC_LAST_UPDATE_TIMER(8),__LC_SYNC_ENTER_TIMER
471 l %r3,__LC_PGM_ILC # load program interruption code
472 l %r4,__LC_TRANS_EXC_CODE
477 l %r1,BASED(.Ljump_table)
478 l %r1,0(%r8,%r1) # load address of handler routine
479 la %r2,SP_PTREGS(%r15) # address of register-save area
480 basr %r14,%r1 # branch to interrupt-handler
485 # handle per exception
488 tm __LC_PGM_OLD_PSW,0x40 # test if per event recording is on
489 bnz BASED(pgm_per_std) # ok, normal per event from user space
490 # ok its one of the special cases, now we need to find out which one
491 clc __LC_PGM_OLD_PSW(8),__LC_SVC_NEW_PSW
493 # no interesting special case, ignore PER event
494 lm %r12,%r15,__LC_SAVE_AREA
498 # Normal per exception
501 SAVE_ALL_PGM __LC_PGM_OLD_PSW,__LC_SAVE_AREA
502 CREATE_STACK_FRAME __LC_SAVE_AREA
503 mvc SP_PSW(8,%r15),__LC_PGM_OLD_PSW
504 l %r12,__LC_THREAD_INFO # load pointer to thread_info struct
505 tm SP_PSW+1(%r15),0x01 # interrupting from user ?
506 bz BASED(pgm_no_vtime2)
507 UPDATE_VTIME __LC_EXIT_TIMER,__LC_SYNC_ENTER_TIMER,__LC_USER_TIMER
508 UPDATE_VTIME __LC_LAST_UPDATE_TIMER,__LC_EXIT_TIMER,__LC_SYSTEM_TIMER
509 mvc __LC_LAST_UPDATE_TIMER(8),__LC_SYNC_ENTER_TIMER
511 l %r1,__TI_task(%r12)
512 tm SP_PSW+1(%r15),0x01 # kernel per event ?
514 mvc __THREAD_per_cause(2,%r1),__LC_PER_CAUSE
515 mvc __THREAD_per_address(4,%r1),__LC_PER_ADDRESS
516 mvc __THREAD_per_paid(1,%r1),__LC_PER_PAID
517 oi __TI_flags+3(%r12),_TIF_PER_TRAP # set TIF_PER_TRAP
518 l %r3,__LC_PGM_ILC # load program interruption code
519 l %r4,__LC_TRANS_EXC_CODE
522 nr %r8,%r3 # clear per-event-bit and ilc
523 be BASED(pgm_exit2) # only per or per+check ?
525 l %r1,BASED(.Ljump_table)
526 l %r1,0(%r8,%r1) # load address of handler routine
527 la %r2,SP_PTREGS(%r15) # address of register-save area
528 basr %r14,%r1 # branch to interrupt-handler
533 # it was a single stepped SVC that is causing all the trouble
536 SAVE_ALL_PGM __LC_SVC_OLD_PSW,__LC_SAVE_AREA
537 CREATE_STACK_FRAME __LC_SAVE_AREA
538 mvc SP_PSW(8,%r15),__LC_SVC_OLD_PSW
539 mvc SP_ILC(4,%r15),__LC_SVC_ILC
540 l %r12,__LC_THREAD_INFO # load pointer to thread_info struct
541 UPDATE_VTIME __LC_EXIT_TIMER,__LC_SYNC_ENTER_TIMER,__LC_USER_TIMER
542 UPDATE_VTIME __LC_LAST_UPDATE_TIMER,__LC_EXIT_TIMER,__LC_SYSTEM_TIMER
543 mvc __LC_LAST_UPDATE_TIMER(8),__LC_SYNC_ENTER_TIMER
544 l %r8,__TI_task(%r12)
545 mvc __THREAD_per_cause(2,%r8),__LC_PER_CAUSE
546 mvc __THREAD_per_address(4,%r8),__LC_PER_ADDRESS
547 mvc __THREAD_per_paid(1,%r8),__LC_PER_PAID
548 oi __TI_flags+3(%r12),_TIF_PER_TRAP # set TIF_PER_TRAP
549 stosm __SF_EMPTY(%r15),0x03 # reenable interrupts
550 lm %r2,%r6,SP_R2(%r15) # load svc arguments
554 # per was called from kernel, must be kprobes
558 xc SP_SVCNR(2,%r15),SP_SVCNR(%r15)
559 la %r2,SP_PTREGS(%r15) # address of register-save area
560 l %r1,BASED(.Lhandle_per) # load adr. of per handler
561 basr %r14,%r1 # branch to do_single_step
565 * IO interrupt handler routine
568 .globl io_int_handler
571 stpt __LC_ASYNC_ENTER_TIMER
572 SAVE_ALL_ASYNC __LC_IO_OLD_PSW,__LC_SAVE_AREA+16
573 CREATE_STACK_FRAME __LC_SAVE_AREA+16
574 mvc SP_PSW(8,%r15),0(%r12) # move user PSW to stack
575 l %r12,__LC_THREAD_INFO # load pointer to thread_info struct
576 tm SP_PSW+1(%r15),0x01 # interrupting from user ?
577 bz BASED(io_no_vtime)
578 UPDATE_VTIME __LC_EXIT_TIMER,__LC_ASYNC_ENTER_TIMER,__LC_USER_TIMER
579 UPDATE_VTIME __LC_LAST_UPDATE_TIMER,__LC_EXIT_TIMER,__LC_SYSTEM_TIMER
580 mvc __LC_LAST_UPDATE_TIMER(8),__LC_ASYNC_ENTER_TIMER
583 l %r1,BASED(.Ldo_IRQ) # load address of do_IRQ
584 la %r2,SP_PTREGS(%r15) # address of register-save area
585 basr %r14,%r1 # branch to standard irq handler
590 tm __TI_flags+3(%r12),_TIF_WORK_INT
591 bnz BASED(io_work) # there is work to do (signals etc.)
593 RESTORE_ALL __LC_RETURN_PSW,0
597 # There is work todo, find out in which context we have been interrupted:
598 # 1) if we return to user space we can do all _TIF_WORK_INT work
599 # 2) if we return to kernel code and preemptive scheduling is enabled check
600 # the preemption counter and if it is zero call preempt_schedule_irq
601 # Before any work can be done, a switch to the kernel stack is required.
604 tm SP_PSW+1(%r15),0x01 # returning to user ?
605 bo BASED(io_work_user) # yes -> do resched & signal
606 #ifdef CONFIG_PREEMPT
607 # check for preemptive scheduling
608 icm %r0,15,__TI_precount(%r12)
609 bnz BASED(io_restore) # preemption disabled
610 tm __TI_flags+3(%r12),_TIF_NEED_RESCHED
611 bno BASED(io_restore)
612 # switch to kernel stack
614 s %r1,BASED(.Lc_spsize)
615 mvc SP_PTREGS(__PT_SIZE,%r1),SP_PTREGS(%r15)
616 xc __SF_BACKCHAIN(4,%r1),__SF_BACKCHAIN(%r1) # clear back chain
618 # TRACE_IRQS_ON already done at io_return, call
619 # TRACE_IRQS_OFF to keep things symmetrical
621 l %r1,BASED(.Lpreempt_schedule_irq)
622 basr %r14,%r1 # call preempt_schedule_irq
629 # Need to do work before returning to userspace, switch to kernel stack
632 l %r1,__LC_KERNEL_STACK
633 s %r1,BASED(.Lc_spsize)
634 mvc SP_PTREGS(__PT_SIZE,%r1),SP_PTREGS(%r15)
635 xc __SF_BACKCHAIN(4,%r1),__SF_BACKCHAIN(%r1) # clear back chain
639 # One of the work bits is on. Find out which one.
640 # Checked are: _TIF_SIGPENDING, _TIF_NOTIFY_RESUME, _TIF_NEED_RESCHED
641 # and _TIF_MCCK_PENDING
644 tm __TI_flags+3(%r12),_TIF_MCCK_PENDING
645 bo BASED(io_mcck_pending)
646 tm __TI_flags+3(%r12),_TIF_NEED_RESCHED
647 bo BASED(io_reschedule)
648 tm __TI_flags+3(%r12),_TIF_SIGPENDING
649 bo BASED(io_sigpending)
650 tm __TI_flags+3(%r12),_TIF_NOTIFY_RESUME
651 bo BASED(io_notify_resume)
652 b BASED(io_return) # beware of critical section cleanup
655 # _TIF_MCCK_PENDING is set, call handler
658 # TRACE_IRQS_ON already done at io_return
659 l %r1,BASED(.Ls390_handle_mcck)
660 basr %r14,%r1 # TIF bit will be cleared by handler
665 # _TIF_NEED_RESCHED is set, call schedule
668 # TRACE_IRQS_ON already done at io_return
669 l %r1,BASED(.Lschedule)
670 stosm __SF_EMPTY(%r15),0x03 # reenable interrupts
671 basr %r14,%r1 # call scheduler
672 stnsm __SF_EMPTY(%r15),0xfc # disable I/O and ext. interrupts
677 # _TIF_SIGPENDING is set, call do_signal
680 # TRACE_IRQS_ON already done at io_return
681 stosm __SF_EMPTY(%r15),0x03 # reenable interrupts
682 la %r2,SP_PTREGS(%r15) # load pt_regs
683 l %r1,BASED(.Ldo_signal)
684 basr %r14,%r1 # call do_signal
685 stnsm __SF_EMPTY(%r15),0xfc # disable I/O and ext. interrupts
690 # _TIF_SIGPENDING is set, call do_signal
693 # TRACE_IRQS_ON already done at io_return
694 stosm __SF_EMPTY(%r15),0x03 # reenable interrupts
695 la %r2,SP_PTREGS(%r15) # load pt_regs
696 l %r1,BASED(.Ldo_notify_resume)
697 basr %r14,%r1 # call do_signal
698 stnsm __SF_EMPTY(%r15),0xfc # disable I/O and ext. interrupts
703 * External interrupt handler routine
706 .globl ext_int_handler
709 stpt __LC_ASYNC_ENTER_TIMER
710 SAVE_ALL_ASYNC __LC_EXT_OLD_PSW,__LC_SAVE_AREA+16
711 CREATE_STACK_FRAME __LC_SAVE_AREA+16
712 mvc SP_PSW(8,%r15),0(%r12) # move user PSW to stack
713 l %r12,__LC_THREAD_INFO # load pointer to thread_info struct
714 tm SP_PSW+1(%r15),0x01 # interrupting from user ?
715 bz BASED(ext_no_vtime)
716 UPDATE_VTIME __LC_EXIT_TIMER,__LC_ASYNC_ENTER_TIMER,__LC_USER_TIMER
717 UPDATE_VTIME __LC_LAST_UPDATE_TIMER,__LC_EXIT_TIMER,__LC_SYSTEM_TIMER
718 mvc __LC_LAST_UPDATE_TIMER(8),__LC_ASYNC_ENTER_TIMER
721 la %r2,SP_PTREGS(%r15) # address of register-save area
722 l %r3,__LC_CPU_ADDRESS # get cpu address + interruption code
723 l %r4,__LC_EXT_PARAMS # get external parameters
724 l %r1,BASED(.Ldo_extint)
731 * Machine check handler routines
734 .globl mcck_int_handler
737 spt __LC_CPU_TIMER_SAVE_AREA # revalidate cpu timer
738 lm %r0,%r15,__LC_GPREGS_SAVE_AREA # revalidate gprs
739 SAVE_ALL_BASE __LC_SAVE_AREA+32
740 la %r12,__LC_MCK_OLD_PSW
741 tm __LC_MCCK_CODE,0x80 # system damage?
742 bo BASED(mcck_int_main) # yes -> rest of mcck code invalid
743 mvc __LC_MCCK_ENTER_TIMER(8),__LC_CPU_TIMER_SAVE_AREA
744 tm __LC_MCCK_CODE+5,0x02 # stored cpu timer value valid?
746 la %r14,__LC_SYNC_ENTER_TIMER
747 clc 0(8,%r14),__LC_ASYNC_ENTER_TIMER
749 la %r14,__LC_ASYNC_ENTER_TIMER
750 0: clc 0(8,%r14),__LC_EXIT_TIMER
752 la %r14,__LC_EXIT_TIMER
753 0: clc 0(8,%r14),__LC_LAST_UPDATE_TIMER
755 la %r14,__LC_LAST_UPDATE_TIMER
757 mvc __LC_MCCK_ENTER_TIMER(8),0(%r14)
758 1: tm __LC_MCCK_CODE+2,0x09 # mwp + ia of old psw valid?
759 bno BASED(mcck_int_main) # no -> skip cleanup critical
760 tm __LC_MCK_OLD_PSW+1,0x01 # test problem state bit
761 bnz BASED(mcck_int_main) # from user -> load async stack
762 clc __LC_MCK_OLD_PSW+4(4),BASED(.Lcritical_end)
763 bhe BASED(mcck_int_main)
764 clc __LC_MCK_OLD_PSW+4(4),BASED(.Lcritical_start)
765 bl BASED(mcck_int_main)
766 l %r14,BASED(.Lcleanup_critical)
769 l %r14,__LC_PANIC_STACK # are we already on the panic stack?
773 l %r15,__LC_PANIC_STACK # load panic stack
774 0: s %r15,BASED(.Lc_spsize) # make room for registers & psw
775 CREATE_STACK_FRAME __LC_SAVE_AREA+32
776 mvc SP_PSW(8,%r15),0(%r12)
777 l %r12,__LC_THREAD_INFO # load pointer to thread_info struct
778 tm __LC_MCCK_CODE+2,0x08 # mwp of old psw valid?
779 bno BASED(mcck_no_vtime) # no -> skip cleanup critical
780 tm SP_PSW+1(%r15),0x01 # interrupting from user ?
781 bz BASED(mcck_no_vtime)
782 UPDATE_VTIME __LC_EXIT_TIMER,__LC_MCCK_ENTER_TIMER,__LC_USER_TIMER
783 UPDATE_VTIME __LC_LAST_UPDATE_TIMER,__LC_EXIT_TIMER,__LC_SYSTEM_TIMER
784 mvc __LC_LAST_UPDATE_TIMER(8),__LC_MCCK_ENTER_TIMER
786 la %r2,SP_PTREGS(%r15) # load pt_regs
787 l %r1,BASED(.Ls390_mcck)
788 basr %r14,%r1 # call machine check handler
789 tm SP_PSW+1(%r15),0x01 # returning to user ?
790 bno BASED(mcck_return)
791 l %r1,__LC_KERNEL_STACK # switch to kernel stack
792 s %r1,BASED(.Lc_spsize)
793 mvc SP_PTREGS(__PT_SIZE,%r1),SP_PTREGS(%r15)
794 xc __SF_BACKCHAIN(4,%r1),__SF_BACKCHAIN(%r1) # clear back chain
796 stosm __SF_EMPTY(%r15),0x04 # turn dat on
797 tm __TI_flags+3(%r12),_TIF_MCCK_PENDING
798 bno BASED(mcck_return)
800 l %r1,BASED(.Ls390_handle_mcck)
801 basr %r14,%r1 # call machine check handler
804 mvc __LC_RETURN_MCCK_PSW(8),SP_PSW(%r15) # move return PSW
805 ni __LC_RETURN_MCCK_PSW+1,0xfd # clear wait state bit
806 tm __LC_RETURN_MCCK_PSW+1,0x01 # returning to user ?
808 lm %r0,%r15,SP_R0(%r15) # load gprs 0-15
810 lpsw __LC_RETURN_MCCK_PSW # back to caller
811 0: lm %r0,%r15,SP_R0(%r15) # load gprs 0-15
812 lpsw __LC_RETURN_MCCK_PSW # back to caller
814 RESTORE_ALL __LC_RETURN_MCCK_PSW,0
817 * Restart interruption handler, kick starter for additional CPUs
821 .globl restart_int_handler
825 spt restart_vtime-restart_base(%r1)
826 stck __LC_LAST_UPDATE_CLOCK
827 mvc __LC_LAST_UPDATE_TIMER(8),restart_vtime-restart_base(%r1)
828 mvc __LC_EXIT_TIMER(8),restart_vtime-restart_base(%r1)
829 l %r15,__LC_SAVE_AREA+60 # load ksp
830 lctl %c0,%c15,__LC_CREGS_SAVE_AREA # get new ctl regs
831 lam %a0,%a15,__LC_AREGS_SAVE_AREA
832 lm %r6,%r15,__SF_GPRS(%r15) # load registers from clone
833 l %r1,__LC_THREAD_INFO
834 mvc __LC_USER_TIMER(8),__TI_user_timer(%r1)
835 mvc __LC_SYSTEM_TIMER(8),__TI_system_timer(%r1)
836 xc __LC_STEAL_TIMER(8),__LC_STEAL_TIMER
837 stosm __SF_EMPTY(%r15),0x04 # now we can turn dat on
839 l %r14,restart_addr-.(%r14)
840 basr %r14,%r14 # branch to start_secondary
842 .long start_secondary
845 .long 0x7fffffff,0xffffffff
849 * If we do not run with SMP enabled, let the new CPU crash ...
851 .globl restart_int_handler
855 lpsw restart_crash-restart_base(%r1)
858 .long 0x000a0000,0x00000000
862 .section .kprobes.text, "ax"
864 #ifdef CONFIG_CHECK_STACK
866 * The synchronous or the asynchronous stack overflowed. We are dead.
867 * No need to properly save the registers, we are going to panic anyway.
868 * Setup a pt_regs so that show_trace can provide a good call trace.
871 l %r15,__LC_PANIC_STACK # change to panic stack
872 sl %r15,BASED(.Lc_spsize)
873 mvc SP_PSW(8,%r15),0(%r12) # move user PSW to stack
874 stm %r0,%r11,SP_R0(%r15) # store gprs %r0-%r11 to kernel stack
875 la %r1,__LC_SAVE_AREA
876 ch %r12,BASED(.L0x020) # old psw addr == __LC_SVC_OLD_PSW ?
878 ch %r12,BASED(.L0x028) # old psw addr == __LC_PGM_OLD_PSW ?
880 la %r1,__LC_SAVE_AREA+16
881 0: mvc SP_R12(16,%r15),0(%r1) # move %r12-%r15 to stack
882 xc __SF_BACKCHAIN(4,%r15),__SF_BACKCHAIN(%r15) # clear back chain
883 l %r1,BASED(1f) # branch to kernel_stack_overflow
884 la %r2,SP_PTREGS(%r15) # load pt_regs
886 1: .long kernel_stack_overflow
889 cleanup_table_system_call:
890 .long system_call + 0x80000000, sysc_do_svc + 0x80000000
891 cleanup_table_sysc_tif:
892 .long sysc_tif + 0x80000000, sysc_restore + 0x80000000
893 cleanup_table_sysc_restore:
894 .long sysc_restore + 0x80000000, sysc_done + 0x80000000
895 cleanup_table_io_tif:
896 .long io_tif + 0x80000000, io_restore + 0x80000000
897 cleanup_table_io_restore:
898 .long io_restore + 0x80000000, io_done + 0x80000000
901 clc 4(4,%r12),BASED(cleanup_table_system_call)
903 clc 4(4,%r12),BASED(cleanup_table_system_call+4)
904 bl BASED(cleanup_system_call)
906 clc 4(4,%r12),BASED(cleanup_table_sysc_tif)
908 clc 4(4,%r12),BASED(cleanup_table_sysc_tif+4)
909 bl BASED(cleanup_sysc_tif)
911 clc 4(4,%r12),BASED(cleanup_table_sysc_restore)
913 clc 4(4,%r12),BASED(cleanup_table_sysc_restore+4)
914 bl BASED(cleanup_sysc_restore)
916 clc 4(4,%r12),BASED(cleanup_table_io_tif)
918 clc 4(4,%r12),BASED(cleanup_table_io_tif+4)
919 bl BASED(cleanup_io_tif)
921 clc 4(4,%r12),BASED(cleanup_table_io_restore)
923 clc 4(4,%r12),BASED(cleanup_table_io_restore+4)
924 bl BASED(cleanup_io_restore)
929 mvc __LC_RETURN_PSW(8),0(%r12)
930 clc __LC_RETURN_PSW+4(4),BASED(cleanup_system_call_insn+4)
932 mvc __LC_SYNC_ENTER_TIMER(8),__LC_MCCK_ENTER_TIMER
933 c %r12,BASED(.Lmck_old_psw)
935 mvc __LC_SYNC_ENTER_TIMER(8),__LC_ASYNC_ENTER_TIMER
936 0: c %r12,BASED(.Lmck_old_psw)
937 la %r12,__LC_SAVE_AREA+32
939 la %r12,__LC_SAVE_AREA+16
940 0: clc __LC_RETURN_PSW+4(4),BASED(cleanup_system_call_insn+8)
941 bhe BASED(cleanup_vtime)
942 clc __LC_RETURN_PSW+4(4),BASED(cleanup_system_call_insn)
944 mvc __LC_SAVE_AREA(16),0(%r12)
946 l %r15,__LC_KERNEL_STACK # problem state -> load ksp
947 s %r15,BASED(.Lc_spsize) # make room for registers & psw
949 CREATE_STACK_FRAME __LC_SAVE_AREA
950 mvc SP_PSW(8,%r15),__LC_SVC_OLD_PSW
951 mvc SP_ILC(4,%r15),__LC_SVC_ILC
952 mvc 0(4,%r12),__LC_THREAD_INFO
954 clc __LC_RETURN_PSW+4(4),BASED(cleanup_system_call_insn+12)
955 bhe BASED(cleanup_stime)
956 UPDATE_VTIME __LC_EXIT_TIMER,__LC_SYNC_ENTER_TIMER,__LC_USER_TIMER
958 clc __LC_RETURN_PSW+4(4),BASED(cleanup_system_call_insn+16)
959 bh BASED(cleanup_update)
960 UPDATE_VTIME __LC_LAST_UPDATE_TIMER,__LC_EXIT_TIMER,__LC_SYSTEM_TIMER
962 mvc __LC_LAST_UPDATE_TIMER(8),__LC_SYNC_ENTER_TIMER
963 mvc __LC_RETURN_PSW+4(4),BASED(cleanup_table_system_call+4)
964 la %r12,__LC_RETURN_PSW
966 cleanup_system_call_insn:
967 .long sysc_saveall + 0x80000000
968 .long system_call + 0x80000000
969 .long sysc_vtime + 0x80000000
970 .long sysc_stime + 0x80000000
971 .long sysc_update + 0x80000000
974 mvc __LC_RETURN_PSW(4),0(%r12)
975 mvc __LC_RETURN_PSW+4(4),BASED(cleanup_table_sysc_tif)
976 la %r12,__LC_RETURN_PSW
979 cleanup_sysc_restore:
980 clc 4(4,%r12),BASED(cleanup_sysc_restore_insn)
982 mvc __LC_EXIT_TIMER(8),__LC_MCCK_ENTER_TIMER
983 c %r12,BASED(.Lmck_old_psw)
985 mvc __LC_EXIT_TIMER(8),__LC_ASYNC_ENTER_TIMER
986 0: clc 4(4,%r12),BASED(cleanup_sysc_restore_insn+4)
988 mvc __LC_RETURN_PSW(8),SP_PSW(%r15)
989 c %r12,BASED(.Lmck_old_psw)
990 la %r12,__LC_SAVE_AREA+32
992 la %r12,__LC_SAVE_AREA+16
993 1: mvc 0(16,%r12),SP_R12(%r15)
994 lm %r0,%r11,SP_R0(%r15)
996 2: la %r12,__LC_RETURN_PSW
998 cleanup_sysc_restore_insn:
999 .long sysc_done - 4 + 0x80000000
1000 .long sysc_done - 8 + 0x80000000
1003 mvc __LC_RETURN_PSW(4),0(%r12)
1004 mvc __LC_RETURN_PSW+4(4),BASED(cleanup_table_io_tif)
1005 la %r12,__LC_RETURN_PSW
1009 clc 4(4,%r12),BASED(cleanup_io_restore_insn)
1011 mvc __LC_EXIT_TIMER(8),__LC_MCCK_ENTER_TIMER
1012 clc 4(4,%r12),BASED(cleanup_io_restore_insn+4)
1014 mvc __LC_RETURN_PSW(8),SP_PSW(%r15)
1015 mvc __LC_SAVE_AREA+32(16),SP_R12(%r15)
1016 lm %r0,%r11,SP_R0(%r15)
1018 1: la %r12,__LC_RETURN_PSW
1020 cleanup_io_restore_insn:
1021 .long io_done - 4 + 0x80000000
1022 .long io_done - 8 + 0x80000000
1028 .Lc_spsize: .long SP_SIZE
1029 .Lc_overhead: .long STACK_FRAME_OVERHEAD
1030 .Lnr_syscalls: .long NR_syscalls
1031 .L0x018: .short 0x018
1032 .L0x020: .short 0x020
1033 .L0x028: .short 0x028
1034 .L0x030: .short 0x030
1035 .L0x038: .short 0x038
1041 .Ls390_mcck: .long s390_do_machine_check
1043 .long s390_handle_mcck
1044 .Lmck_old_psw: .long __LC_MCK_OLD_PSW
1045 .Ldo_IRQ: .long do_IRQ
1046 .Ldo_extint: .long do_extint
1047 .Ldo_signal: .long do_signal
1049 .long do_notify_resume
1050 .Lhandle_per: .long do_per_trap
1051 .Ldo_execve: .long do_execve
1052 .Lexecve_tail: .long execve_tail
1053 .Ljump_table: .long pgm_check_table
1054 .Lschedule: .long schedule
1055 #ifdef CONFIG_PREEMPT
1056 .Lpreempt_schedule_irq:
1057 .long preempt_schedule_irq
1059 .Ltrace_entry: .long do_syscall_trace_enter
1060 .Ltrace_exit: .long do_syscall_trace_exit
1061 .Lschedtail: .long schedule_tail
1062 .Lsysc_table: .long sys_call_table
1063 #ifdef CONFIG_TRACE_IRQFLAGS
1064 .Ltrace_irq_on_caller:
1065 .long trace_hardirqs_on_caller
1066 .Ltrace_irq_off_caller:
1067 .long trace_hardirqs_off_caller
1069 #ifdef CONFIG_LOCKDEP
1071 .long lockdep_sys_exit
1074 .long __critical_start + 0x80000000
1076 .long __critical_end + 0x80000000
1078 .long cleanup_critical
1080 .section .rodata, "a"
1081 #define SYSCALL(esa,esame,emu) .long esa
1082 .globl sys_call_table
1084 #include "syscalls.S"