LXR linux/arch/s390/kernel/entry.S

   1/*
   2 *    S390 low-level entry points.
   3 *
   4 *    Copyright IBM Corp. 1999, 2012
   5 *    Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
   6 *               Hartmut Penner (hp@de.ibm.com),
   7 *               Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com),
   8 *               Heiko Carstens <heiko.carstens@de.ibm.com>
   9 */
  10
  11#include <linux/init.h>
  12#include <linux/linkage.h>
  13#include <asm/cache.h>
  14#include <asm/errno.h>
  15#include <asm/ptrace.h>
  16#include <asm/thread_info.h>
  17#include <asm/asm-offsets.h>
  18#include <asm/unistd.h>
  19#include <asm/page.h>
  20#include <asm/sigp.h>
  21
  22__PT_R0      =  __PT_GPRS
  23__PT_R1      =  __PT_GPRS + 4
  24__PT_R2      =  __PT_GPRS + 8
  25__PT_R3      =  __PT_GPRS + 12
  26__PT_R4      =  __PT_GPRS + 16
  27__PT_R5      =  __PT_GPRS + 20
  28__PT_R6      =  __PT_GPRS + 24
  29__PT_R7      =  __PT_GPRS + 28
  30__PT_R8      =  __PT_GPRS + 32
  31__PT_R9      =  __PT_GPRS + 36
  32__PT_R10     =  __PT_GPRS + 40
  33__PT_R11     =  __PT_GPRS + 44
  34__PT_R12     =  __PT_GPRS + 48
  35__PT_R13     =  __PT_GPRS + 524
  36__PT_R14     =  __PT_GPRS + 56
  37__PT_R15     =  __PT_GPRS + 60
  38
  39_TIF_WORK_SVC = (_TIF_SIGPENDING | _TIF_NOTIFY_RESUME | _TIF_NEED_RESCHED | \
  40                 _TIF_MCCK_PENDING | _TIF_PER_TRAP )
  41_TIF_WORK_INT = (_TIF_SIGPENDING | _TIF_NOTIFY_RESUME | _TIF_NEED_RESCHED | \
  42                 _TIF_MCCK_PENDING)
  43_TIF_TRACE    = (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | _TIF_SECCOMP | \
  44                 _TIF_SYSCALL_TRACEPOINT)
  45
  46STACK_SHIFT = PAGE_SHIFT + THREAD_ORDER
  47STACK_SIZE  = 1 << STACK_SHIFT
  48STACK_INIT  = STACK_SIZE - STACK_FRAME_OVERHEAD - __PT_SIZE
  49
  50#define BASED(name) name-system_call(%r13)
  51
  52        .macro  TRACE_IRQS_ON
  53#ifdef CONFIG_TRACE_IRQFLAGS
  54        basr    %r2,%r0
  55        l       %r1,BASED(.Lhardirqs_on)
  56        basr    %r14,%r1                # call trace_hardirqs_on_caller
  57#endif
  58        .endm
  59
  60        .macro  TRACE_IRQS_OFF
  61#ifdef CONFIG_TRACE_IRQFLAGS
  62        basr    %r2,%r0
  63        l       %r1,BASED(.Lhardirqs_off)
  64        basr    %r14,%r1                # call trace_hardirqs_off_caller
  65#endif
  66        .endm
  67
  68        .macro  LOCKDEP_SYS_EXIT
  69#ifdef CONFIG_LOCKDEP
  70        tm      __PT_PSW+1(%r11),0x01   # returning to user ?
  71        jz      .+10
  72        l       %r1,BASED(.Llockdep_sys_exit)
  73        basr    %r14,%r1                # call lockdep_sys_exit
  74#endif
  75        .endm
  76
  77        .macro  CHECK_STACK stacksize,savearea
  78#ifdef CONFIG_CHECK_STACK
  79        tml     %r15,\stacksize - CONFIG_STACK_GUARD
  80        la      %r14,\savearea
  81        jz      stack_overflow
  82#endif
  83        .endm
  84
  85        .macro  SWITCH_ASYNC savearea,stack,shift
  86        tmh     %r8,0x0001              # interrupting from user ?
  87        jnz     1f
  88        lr      %r14,%r9
  89        sl      %r14,BASED(.Lcritical_start)
  90        cl      %r14,BASED(.Lcritical_length)
  91        jhe     0f
  92        la      %r11,\savearea          # inside critical section, do cleanup
  93        bras    %r14,cleanup_critical
  94        tmh     %r8,0x0001              # retest problem state after cleanup
  95        jnz     1f
  960:      l       %r14,\stack             # are we already on the target stack?
  97        slr     %r14,%r15
  98        sra     %r14,\shift
  99        jnz     1f
 100        CHECK_STACK 1<<\shift,\savearea
 101        ahi     %r15,-(STACK_FRAME_OVERHEAD + __PT_SIZE)
 102        j       2f
 1031:      l       %r15,\stack             # load target stack
 1042:      la      %r11,STACK_FRAME_OVERHEAD(%r15)
 105        .endm
 106
 107        .macro  ADD64 high,low,timer
 108        al      \high,\timer
 109        al      \low,4+\timer
 110        brc     12,.+8
 111        ahi     \high,1
 112        .endm
 113
 114        .macro  SUB64 high,low,timer
 115        sl      \high,\timer
 116        sl      \low,4+\timer
 117        brc     3,.+8
 118        ahi     \high,-1
 119        .endm
 120
 121        .macro  UPDATE_VTIME high,low,enter_timer
 122        lm      \high,\low,__LC_EXIT_TIMER
 123        SUB64   \high,\low,\enter_timer
 124        ADD64   \high,\low,__LC_USER_TIMER
 125        stm     \high,\low,__LC_USER_TIMER
 126        lm      \high,\low,__LC_LAST_UPDATE_TIMER
 127        SUB64   \high,\low,__LC_EXIT_TIMER
 128        ADD64   \high,\low,__LC_SYSTEM_TIMER
 129        stm     \high,\low,__LC_SYSTEM_TIMER
 130        mvc     __LC_LAST_UPDATE_TIMER(8),\enter_timer
 131        .endm
 132
 133        .macro REENABLE_IRQS
 134        st      %r8,__LC_RETURN_PSW
 135        ni      __LC_RETURN_PSW,0xbf
 136        ssm     __LC_RETURN_PSW
 137        .endm
 138
 139        .section .kprobes.text, "ax"
 140
 141/*
 142 * Scheduler resume function, called by switch_to
 143 *  gpr2 = (task_struct *) prev
 144 *  gpr3 = (task_struct *) next
 145 * Returns:
 146 *  gpr2 = prev
 147 */
 148ENTRY(__switch_to)
 149        stm     %r6,%r15,__SF_GPRS(%r15)        # store gprs of prev task
 150        st      %r15,__THREAD_ksp(%r2)          # store kernel stack of prev
 151        l       %r4,__THREAD_info(%r2)          # get thread_info of prev
 152        l       %r5,__THREAD_info(%r3)          # get thread_info of next
 153        lr      %r15,%r5
 154        ahi     %r15,STACK_INIT                 # end of kernel stack of next
 155        st      %r3,__LC_CURRENT                # store task struct of next
 156        st      %r5,__LC_THREAD_INFO            # store thread info of next
 157        st      %r15,__LC_KERNEL_STACK          # store end of kernel stack
 158        lctl    %c4,%c4,__TASK_pid(%r3)         # load pid to control reg. 4
 159        mvc     __LC_CURRENT_PID(4,%r0),__TASK_pid(%r3) # store pid of next
 160        l       %r15,__THREAD_ksp(%r3)          # load kernel stack of next
 161        tm      __TI_flags+3(%r4),_TIF_MCCK_PENDING # machine check pending?
 162        jz      0f
 163        ni      __TI_flags+3(%r4),255-_TIF_MCCK_PENDING # clear flag in prev
 164        oi      __TI_flags+3(%r5),_TIF_MCCK_PENDING     # set it in next
 1650:      lm      %r6,%r15,__SF_GPRS(%r15)        # load gprs of next task
 166        br      %r14
 167
 168__critical_start:
 169/*
 170 * SVC interrupt handler routine. System calls are synchronous events and
 171 * are executed with interrupts enabled.
 172 */
 173
 174ENTRY(system_call)
 175        stpt    __LC_SYNC_ENTER_TIMER
 176sysc_stm:
 177        stm     %r8,%r15,__LC_SAVE_AREA_SYNC
 178        l       %r12,__LC_THREAD_INFO
 179        l       %r13,__LC_SVC_NEW_PSW+4
 180sysc_per:
 181        l       %r15,__LC_KERNEL_STACK
 182        la      %r11,STACK_FRAME_OVERHEAD(%r15) # pointer to pt_regs
 183sysc_vtime:
 184        UPDATE_VTIME %r8,%r9,__LC_SYNC_ENTER_TIMER
 185        stm     %r0,%r7,__PT_R0(%r11)
 186        mvc     __PT_R8(32,%r11),__LC_SAVE_AREA_SYNC
 187        mvc     __PT_PSW(8,%r11),__LC_SVC_OLD_PSW
 188        mvc     __PT_INT_CODE(4,%r11),__LC_SVC_ILC
 189sysc_do_svc:
 190        oi      __TI_flags+3(%r12),_TIF_SYSCALL
 191        l       %r10,__TI_sysc_table(%r12)      # 31 bit system call table
 192        lh      %r8,__PT_INT_CODE+2(%r11)
 193        sla     %r8,2                           # shift and test for svc0
 194        jnz     sysc_nr_ok
 195        # svc 0: system call number in %r1
 196        cl      %r1,BASED(.Lnr_syscalls)
 197        jnl     sysc_nr_ok
 198        sth     %r1,__PT_INT_CODE+2(%r11)
 199        lr      %r8,%r1
 200        sla     %r8,2
 201sysc_nr_ok:
 202        xc      __SF_BACKCHAIN(4,%r15),__SF_BACKCHAIN(%r15)
 203        st      %r2,__PT_ORIG_GPR2(%r11)
 204        st      %r7,STACK_FRAME_OVERHEAD(%r15)
 205        l       %r9,0(%r8,%r10)                 # get system call addr.
 206        tm      __TI_flags+2(%r12),_TIF_TRACE >> 8
 207        jnz     sysc_tracesys
 208        basr    %r14,%r9                        # call sys_xxxx
 209        st      %r2,__PT_R2(%r11)               # store return value
 210
 211sysc_return:
 212        LOCKDEP_SYS_EXIT
 213sysc_tif:
 214        tm      __PT_PSW+1(%r11),0x01           # returning to user ?
 215        jno     sysc_restore
 216        tm      __TI_flags+3(%r12),_TIF_WORK_SVC
 217        jnz     sysc_work                       # check for work
 218        ni      __TI_flags+3(%r12),255-_TIF_SYSCALL
 219sysc_restore:
 220        mvc     __LC_RETURN_PSW(8),__PT_PSW(%r11)
 221        stpt    __LC_EXIT_TIMER
 222        lm      %r0,%r15,__PT_R0(%r11)
 223        lpsw    __LC_RETURN_PSW
 224sysc_done:
 225
 226#
 227# One of the work bits is on. Find out which one.
 228#
 229sysc_work:
 230        tm      __TI_flags+3(%r12),_TIF_MCCK_PENDING
 231        jo      sysc_mcck_pending
 232        tm      __TI_flags+3(%r12),_TIF_NEED_RESCHED
 233        jo      sysc_reschedule
 234        tm      __TI_flags+3(%r12),_TIF_PER_TRAP
 235        jo      sysc_singlestep
 236        tm      __TI_flags+3(%r12),_TIF_SIGPENDING
 237        jo      sysc_sigpending
 238        tm      __TI_flags+3(%r12),_TIF_NOTIFY_RESUME
 239        jo      sysc_notify_resume
 240        j       sysc_return             # beware of critical section cleanup
 241
 242#
 243# _TIF_NEED_RESCHED is set, call schedule
 244#
 245sysc_reschedule:
 246        l       %r1,BASED(.Lschedule)
 247        la      %r14,BASED(sysc_return)
 248        br      %r1                     # call schedule
 249
 250#
 251# _TIF_MCCK_PENDING is set, call handler
 252#
 253sysc_mcck_pending:
 254        l       %r1,BASED(.Lhandle_mcck)
 255        la      %r14,BASED(sysc_return)
 256        br      %r1                     # TIF bit will be cleared by handler
 257
 258#
 259# _TIF_SIGPENDING is set, call do_signal
 260#
 261sysc_sigpending:
 262        lr      %r2,%r11                # pass pointer to pt_regs
 263        l       %r1,BASED(.Ldo_signal)
 264        basr    %r14,%r1                # call do_signal
 265        tm      __TI_flags+3(%r12),_TIF_SYSCALL
 266        jno     sysc_return
 267        lm      %r2,%r7,__PT_R2(%r11)   # load svc arguments
 268        xr      %r8,%r8                 # svc 0 returns -ENOSYS
 269        clc     __PT_INT_CODE+2(2,%r11),BASED(.Lnr_syscalls+2)
 270        jnl     sysc_nr_ok              # invalid svc number -> do svc 0
 271        lh      %r8,__PT_INT_CODE+2(%r11)       # load new svc number
 272        sla     %r8,2
 273        j       sysc_nr_ok              # restart svc
 274
 275#
 276# _TIF_NOTIFY_RESUME is set, call do_notify_resume
 277#
 278sysc_notify_resume:
 279        lr      %r2,%r11                # pass pointer to pt_regs
 280        l       %r1,BASED(.Ldo_notify_resume)
 281        la      %r14,BASED(sysc_return)
 282        br      %r1                     # call do_notify_resume
 283
 284#
 285# _TIF_PER_TRAP is set, call do_per_trap
 286#
 287sysc_singlestep:
 288        ni      __TI_flags+3(%r12),255-_TIF_PER_TRAP
 289        lr      %r2,%r11                # pass pointer to pt_regs
 290        l       %r1,BASED(.Ldo_per_trap)
 291        la      %r14,BASED(sysc_return)
 292        br      %r1                     # call do_per_trap
 293
 294#
 295# call tracehook_report_syscall_entry/tracehook_report_syscall_exit before
 296# and after the system call
 297#
 298sysc_tracesys:
 299        l       %r1,BASED(.Ltrace_enter)
 300        lr      %r2,%r11                # pass pointer to pt_regs
 301        la      %r3,0
 302        xr      %r0,%r0
 303        icm     %r0,3,__PT_INT_CODE+2(%r11)
 304        st      %r0,__PT_R2(%r11)
 305        basr    %r14,%r1                # call do_syscall_trace_enter
 306        cl      %r2,BASED(.Lnr_syscalls)
 307        jnl     sysc_tracenogo
 308        lr      %r8,%r2
 309        sll     %r8,2
 310        l       %r9,0(%r8,%r10)
 311sysc_tracego:
 312        lm      %r3,%r7,__PT_R3(%r11)
 313        st      %r7,STACK_FRAME_OVERHEAD(%r15)
 314        l       %r2,__PT_ORIG_GPR2(%r11)
 315        basr    %r14,%r9                # call sys_xxx
 316        st      %r2,__PT_R2(%r11)       # store return value
 317sysc_tracenogo:
 318        tm      __TI_flags+2(%r12),_TIF_TRACE >> 8
 319        jz      sysc_return
 320        l       %r1,BASED(.Ltrace_exit)
 321        lr      %r2,%r11                # pass pointer to pt_regs
 322        la      %r14,BASED(sysc_return)
 323        br      %r1                     # call do_syscall_trace_exit
 324
 325#
 326# a new process exits the kernel with ret_from_fork
 327#
 328ENTRY(ret_from_fork)
 329        la      %r11,STACK_FRAME_OVERHEAD(%r15)
 330        l       %r12,__LC_THREAD_INFO
 331        l       %r13,__LC_SVC_NEW_PSW+4
 332        l       %r1,BASED(.Lschedule_tail)
 333        basr    %r14,%r1                # call schedule_tail
 334        TRACE_IRQS_ON
 335        ssm     __LC_SVC_NEW_PSW        # reenable interrupts
 336        tm      __PT_PSW+1(%r11),0x01   # forking a kernel thread ?
 337        jne     sysc_tracenogo
 338        # it's a kernel thread
 339        lm      %r9,%r10,__PT_R9(%r11)  # load gprs
 340ENTRY(kernel_thread_starter)
 341        la      %r2,0(%r10)
 342        basr    %r14,%r9
 343        j       sysc_tracenogo
 344
 345/*
 346 * Program check handler routine
 347 */
 348
 349ENTRY(pgm_check_handler)
 350        stpt    __LC_SYNC_ENTER_TIMER
 351        stm     %r8,%r15,__LC_SAVE_AREA_SYNC
 352        l       %r12,__LC_THREAD_INFO
 353        l       %r13,__LC_SVC_NEW_PSW+4
 354        lm      %r8,%r9,__LC_PGM_OLD_PSW
 355        tmh     %r8,0x0001              # test problem state bit
 356        jnz     1f                      # -> fault in user space
 357        tmh     %r8,0x4000              # PER bit set in old PSW ?
 358        jnz     0f                      # -> enabled, can't be a double fault
 359        tm      __LC_PGM_ILC+3,0x80     # check for per exception
 360        jnz     pgm_svcper              # -> single stepped svc
 3610:      CHECK_STACK STACK_SIZE,__LC_SAVE_AREA_SYNC
 362        ahi     %r15,-(STACK_FRAME_OVERHEAD + __PT_SIZE)
 363        j       2f
 3641:      UPDATE_VTIME %r14,%r15,__LC_SYNC_ENTER_TIMER
 365        l       %r15,__LC_KERNEL_STACK
 3662:      la      %r11,STACK_FRAME_OVERHEAD(%r15)
 367        stm     %r0,%r7,__PT_R0(%r11)
 368        mvc     __PT_R8(32,%r11),__LC_SAVE_AREA_SYNC
 369        stm     %r8,%r9,__PT_PSW(%r11)
 370        mvc     __PT_INT_CODE(4,%r11),__LC_PGM_ILC
 371        mvc     __PT_INT_PARM_LONG(4,%r11),__LC_TRANS_EXC_CODE
 372        tm      __LC_PGM_ILC+3,0x80     # check for per exception
 373        jz      0f
 374        l       %r1,__TI_task(%r12)
 375        tmh     %r8,0x0001              # kernel per event ?
 376        jz      pgm_kprobe
 377        oi      __TI_flags+3(%r12),_TIF_PER_TRAP
 378        mvc     __THREAD_per_address(4,%r1),__LC_PER_ADDRESS
 379        mvc     __THREAD_per_cause(2,%r1),__LC_PER_CAUSE
 380        mvc     __THREAD_per_paid(1,%r1),__LC_PER_PAID
 3810:      REENABLE_IRQS
 382        xc      __SF_BACKCHAIN(4,%r15),__SF_BACKCHAIN(%r15)
 383        l       %r1,BASED(.Ljump_table)
 384        la      %r10,0x7f
 385        n       %r10,__PT_INT_CODE(%r11)
 386        je      sysc_return
 387        sll     %r10,2
 388        l       %r1,0(%r10,%r1)         # load address of handler routine
 389        lr      %r2,%r11                # pass pointer to pt_regs
 390        basr    %r14,%r1                # branch to interrupt-handler
 391        j       sysc_return
 392
 393#
 394# PER event in supervisor state, must be kprobes
 395#
 396pgm_kprobe:
 397        REENABLE_IRQS
 398        xc      __SF_BACKCHAIN(4,%r15),__SF_BACKCHAIN(%r15)
 399        l       %r1,BASED(.Ldo_per_trap)
 400        lr      %r2,%r11                # pass pointer to pt_regs
 401        basr    %r14,%r1                # call do_per_trap
 402        j       sysc_return
 403
 404#
 405# single stepped system call
 406#
 407pgm_svcper:
 408        oi      __TI_flags+3(%r12),_TIF_PER_TRAP
 409        mvc     __LC_RETURN_PSW(4),__LC_SVC_NEW_PSW
 410        mvc     __LC_RETURN_PSW+4(4),BASED(.Lsysc_per)
 411        lpsw    __LC_RETURN_PSW         # branch to sysc_per and enable irqs
 412
 413/*
 414 * IO interrupt handler routine
 415 */
 416
 417ENTRY(io_int_handler)
 418        stck    __LC_INT_CLOCK
 419        stpt    __LC_ASYNC_ENTER_TIMER
 420        stm     %r8,%r15,__LC_SAVE_AREA_ASYNC
 421        l       %r12,__LC_THREAD_INFO
 422        l       %r13,__LC_SVC_NEW_PSW+4
 423        lm      %r8,%r9,__LC_IO_OLD_PSW
 424        tmh     %r8,0x0001              # interrupting from user ?
 425        jz      io_skip
 426        UPDATE_VTIME %r14,%r15,__LC_ASYNC_ENTER_TIMER
 427io_skip:
 428        SWITCH_ASYNC __LC_SAVE_AREA_ASYNC,__LC_ASYNC_STACK,STACK_SHIFT
 429        stm     %r0,%r7,__PT_R0(%r11)
 430        mvc     __PT_R8(32,%r11),__LC_SAVE_AREA_ASYNC
 431        stm     %r8,%r9,__PT_PSW(%r11)
 432        TRACE_IRQS_OFF
 433        xc      __SF_BACKCHAIN(4,%r15),__SF_BACKCHAIN(%r15)
 434        l       %r1,BASED(.Ldo_IRQ)
 435        lr      %r2,%r11                # pass pointer to pt_regs
 436        basr    %r14,%r1                # call do_IRQ
 437io_return:
 438        LOCKDEP_SYS_EXIT
 439        TRACE_IRQS_ON
 440io_tif:
 441        tm      __TI_flags+3(%r12),_TIF_WORK_INT
 442        jnz     io_work                 # there is work to do (signals etc.)
 443io_restore:
 444        mvc     __LC_RETURN_PSW(8),__PT_PSW(%r11)
 445        stpt    __LC_EXIT_TIMER
 446        lm      %r0,%r15,__PT_R0(%r11)
 447        lpsw    __LC_RETURN_PSW
 448io_done:
 449
 450#
 451# There is work todo, find out in which context we have been interrupted:
 452# 1) if we return to user space we can do all _TIF_WORK_INT work
 453# 2) if we return to kernel code and preemptive scheduling is enabled check
 454#    the preemption counter and if it is zero call preempt_schedule_irq
 455# Before any work can be done, a switch to the kernel stack is required.
 456#
 457io_work:
 458        tm      __PT_PSW+1(%r11),0x01   # returning to user ?
 459        jo      io_work_user            # yes -> do resched & signal
 460#ifdef CONFIG_PREEMPT
 461        # check for preemptive scheduling
 462        icm     %r0,15,__TI_precount(%r12)
 463        jnz     io_restore              # preemption disabled
 464        tm      __TI_flags+3(%r12),_TIF_NEED_RESCHED
 465        jno     io_restore
 466        # switch to kernel stack
 467        l       %r1,__PT_R15(%r11)
 468        ahi     %r1,-(STACK_FRAME_OVERHEAD + __PT_SIZE)
 469        mvc     STACK_FRAME_OVERHEAD(__PT_SIZE,%r1),0(%r11)
 470        xc      __SF_BACKCHAIN(4,%r1),__SF_BACKCHAIN(%r1)
 471        la      %r11,STACK_FRAME_OVERHEAD(%r1)
 472        lr      %r15,%r1
 473        # TRACE_IRQS_ON already done at io_return, call
 474        # TRACE_IRQS_OFF to keep things symmetrical
 475        TRACE_IRQS_OFF
 476        l       %r1,BASED(.Lpreempt_irq)
 477        basr    %r14,%r1                # call preempt_schedule_irq
 478        j       io_return
 479#else
 480        j       io_restore
 481#endif
 482
 483#
 484# Need to do work before returning to userspace, switch to kernel stack
 485#
 486io_work_user:
 487        l       %r1,__LC_KERNEL_STACK
 488        mvc     STACK_FRAME_OVERHEAD(__PT_SIZE,%r1),0(%r11)
 489        xc      __SF_BACKCHAIN(4,%r1),__SF_BACKCHAIN(%r1)
 490        la      %r11,STACK_FRAME_OVERHEAD(%r1)
 491        lr      %r15,%r1
 492
 493#
 494# One of the work bits is on. Find out which one.
 495# Checked are: _TIF_SIGPENDING, _TIF_NOTIFY_RESUME, _TIF_NEED_RESCHED
 496#               and _TIF_MCCK_PENDING
 497#
 498io_work_tif:
 499        tm      __TI_flags+3(%r12),_TIF_MCCK_PENDING
 500        jo      io_mcck_pending
 501        tm      __TI_flags+3(%r12),_TIF_NEED_RESCHED
 502        jo      io_reschedule
 503        tm      __TI_flags+3(%r12),_TIF_SIGPENDING
 504        jo      io_sigpending
 505        tm      __TI_flags+3(%r12),_TIF_NOTIFY_RESUME
 506        jo      io_notify_resume
 507        j       io_return               # beware of critical section cleanup
 508
 509#
 510# _TIF_MCCK_PENDING is set, call handler
 511#
 512io_mcck_pending:
 513        # TRACE_IRQS_ON already done at io_return
 514        l       %r1,BASED(.Lhandle_mcck)
 515        basr    %r14,%r1                # TIF bit will be cleared by handler
 516        TRACE_IRQS_OFF
 517        j       io_return
 518
 519#
 520# _TIF_NEED_RESCHED is set, call schedule
 521#
 522io_reschedule:
 523        # TRACE_IRQS_ON already done at io_return
 524        l       %r1,BASED(.Lschedule)
 525        ssm     __LC_SVC_NEW_PSW        # reenable interrupts
 526        basr    %r14,%r1                # call scheduler
 527        ssm     __LC_PGM_NEW_PSW        # disable I/O and ext. interrupts
 528        TRACE_IRQS_OFF
 529        j       io_return
 530
 531#
 532# _TIF_SIGPENDING is set, call do_signal
 533#
 534io_sigpending:
 535        # TRACE_IRQS_ON already done at io_return
 536        l       %r1,BASED(.Ldo_signal)
 537        ssm     __LC_SVC_NEW_PSW        # reenable interrupts
 538        lr      %r2,%r11                # pass pointer to pt_regs
 539        basr    %r14,%r1                # call do_signal
 540        ssm     __LC_PGM_NEW_PSW        # disable I/O and ext. interrupts
 541        TRACE_IRQS_OFF
 542        j       io_return
 543
 544#
 545# _TIF_SIGPENDING is set, call do_signal
 546#
 547io_notify_resume:
 548        # TRACE_IRQS_ON already done at io_return
 549        l       %r1,BASED(.Ldo_notify_resume)
 550        ssm     __LC_SVC_NEW_PSW        # reenable interrupts
 551        lr      %r2,%r11                # pass pointer to pt_regs
 552        basr    %r14,%r1                # call do_notify_resume
 553        ssm     __LC_PGM_NEW_PSW        # disable I/O and ext. interrupts
 554        TRACE_IRQS_OFF
 555        j       io_return
 556
 557/*
 558 * External interrupt handler routine
 559 */
 560
 561ENTRY(ext_int_handler)
 562        stck    __LC_INT_CLOCK
 563        stpt    __LC_ASYNC_ENTER_TIMER
 564        stm     %r8,%r15,__LC_SAVE_AREA_ASYNC
 565        l       %r12,__LC_THREAD_INFO
 566        l       %r13,__LC_SVC_NEW_PSW+4
 567        lm      %r8,%r9,__LC_EXT_OLD_PSW
 568        tmh     %r8,0x0001              # interrupting from user ?
 569        jz      ext_skip
 570        UPDATE_VTIME %r14,%r15,__LC_ASYNC_ENTER_TIMER
 571ext_skip:
 572        SWITCH_ASYNC __LC_SAVE_AREA_ASYNC,__LC_ASYNC_STACK,STACK_SHIFT
 573        stm     %r0,%r7,__PT_R0(%r11)
 574        mvc     __PT_R8(32,%r11),__LC_SAVE_AREA_ASYNC
 575        stm     %r8,%r9,__PT_PSW(%r11)
 576        TRACE_IRQS_OFF
 577        lr      %r2,%r11                # pass pointer to pt_regs
 578        l       %r3,__LC_EXT_CPU_ADDR   # get cpu address + interruption code
 579        l       %r4,__LC_EXT_PARAMS     # get external parameters
 580        l       %r1,BASED(.Ldo_extint)
 581        basr    %r14,%r1                # call do_extint
 582        j       io_return
 583
 584/*
 585 * Load idle PSW. The second "half" of this function is in cleanup_idle.
 586 */
 587ENTRY(psw_idle)
 588        st      %r3,__SF_EMPTY(%r15)
 589        basr    %r1,0
 590        la      %r1,psw_idle_lpsw+4-.(%r1)
 591        st      %r1,__SF_EMPTY+4(%r15)
 592        oi      __SF_EMPTY+4(%r15),0x80
 593        stck    __CLOCK_IDLE_ENTER(%r2)
 594        stpt    __TIMER_IDLE_ENTER(%r2)
 595psw_idle_lpsw:
 596        lpsw    __SF_EMPTY(%r15)
 597        br      %r14
 598psw_idle_end:
 599
 600__critical_end:
 601
 602/*
 603 * Machine check handler routines
 604 */
 605
 606ENTRY(mcck_int_handler)
 607        stck    __LC_MCCK_CLOCK
 608        spt     __LC_CPU_TIMER_SAVE_AREA        # revalidate cpu timer
 609        lm      %r0,%r15,__LC_GPREGS_SAVE_AREA  # revalidate gprs
 610        l       %r12,__LC_THREAD_INFO
 611        l       %r13,__LC_SVC_NEW_PSW+4
 612        lm      %r8,%r9,__LC_MCK_OLD_PSW
 613        tm      __LC_MCCK_CODE,0x80     # system damage?
 614        jo      mcck_panic              # yes -> rest of mcck code invalid
 615        la      %r14,__LC_CPU_TIMER_SAVE_AREA
 616        mvc     __LC_MCCK_ENTER_TIMER(8),0(%r14)
 617        tm      __LC_MCCK_CODE+5,0x02   # stored cpu timer value valid?
 618        jo      3f
 619        la      %r14,__LC_SYNC_ENTER_TIMER
 620        clc     0(8,%r14),__LC_ASYNC_ENTER_TIMER
 621        jl      0f
 622        la      %r14,__LC_ASYNC_ENTER_TIMER
 6230:      clc     0(8,%r14),__LC_EXIT_TIMER
 624        jl      1f
 625        la      %r14,__LC_EXIT_TIMER
 6261:      clc     0(8,%r14),__LC_LAST_UPDATE_TIMER
 627        jl      2f
 628        la      %r14,__LC_LAST_UPDATE_TIMER
 6292:      spt     0(%r14)
 630        mvc     __LC_MCCK_ENTER_TIMER(8),0(%r14)
 6313:      tm      __LC_MCCK_CODE+2,0x09   # mwp + ia of old psw valid?
 632        jno     mcck_panic              # no -> skip cleanup critical
 633        tm      %r8,0x0001              # interrupting from user ?
 634        jz      mcck_skip
 635        UPDATE_VTIME %r14,%r15,__LC_MCCK_ENTER_TIMER
 636mcck_skip:
 637        SWITCH_ASYNC __LC_GPREGS_SAVE_AREA+32,__LC_PANIC_STACK,PAGE_SHIFT
 638        stm     %r0,%r7,__PT_R0(%r11)
 639        mvc     __PT_R8(32,%r11),__LC_GPREGS_SAVE_AREA+32
 640        stm     %r8,%r9,__PT_PSW(%r11)
 641        xc      __SF_BACKCHAIN(4,%r15),__SF_BACKCHAIN(%r15)
 642        l       %r1,BASED(.Ldo_machine_check)
 643        lr      %r2,%r11                # pass pointer to pt_regs
 644        basr    %r14,%r1                # call s390_do_machine_check
 645        tm      __PT_PSW+1(%r11),0x01   # returning to user ?
 646        jno     mcck_return
 647        l       %r1,__LC_KERNEL_STACK   # switch to kernel stack
 648        mvc     STACK_FRAME_OVERHEAD(__PT_SIZE,%r1),0(%r11)
 649        xc      __SF_BACKCHAIN(4,%r1),__SF_BACKCHAIN(%r1)
 650        la      %r11,STACK_FRAME_OVERHEAD(%r15)
 651        lr      %r15,%r1
 652        ssm     __LC_PGM_NEW_PSW        # turn dat on, keep irqs off
 653        tm      __TI_flags+3(%r12),_TIF_MCCK_PENDING
 654        jno     mcck_return
 655        TRACE_IRQS_OFF
 656        l       %r1,BASED(.Lhandle_mcck)
 657        basr    %r14,%r1                # call s390_handle_mcck
 658        TRACE_IRQS_ON
 659mcck_return:
 660        mvc     __LC_RETURN_MCCK_PSW(8),__PT_PSW(%r11) # move return PSW
 661        tm      __LC_RETURN_MCCK_PSW+1,0x01 # returning to user ?
 662        jno     0f
 663        lm      %r0,%r15,__PT_R0(%r11)
 664        stpt    __LC_EXIT_TIMER
 665        lpsw    __LC_RETURN_MCCK_PSW
 6660:      lm      %r0,%r15,__PT_R0(%r11)
 667        lpsw    __LC_RETURN_MCCK_PSW
 668
 669mcck_panic:
 670        l       %r14,__LC_PANIC_STACK
 671        slr     %r14,%r15
 672        sra     %r14,PAGE_SHIFT
 673        jz      0f
 674        l       %r15,__LC_PANIC_STACK
 675        j       mcck_skip
 6760:      ahi     %r15,-(STACK_FRAME_OVERHEAD + __PT_SIZE)
 677        j       mcck_skip
 678
 679#
 680# PSW restart interrupt handler
 681#
 682ENTRY(restart_int_handler)
 683        st      %r15,__LC_SAVE_AREA_RESTART
 684        l       %r15,__LC_RESTART_STACK
 685        ahi     %r15,-__PT_SIZE                 # create pt_regs on stack
 686        xc      0(__PT_SIZE,%r15),0(%r15)
 687        stm     %r0,%r14,__PT_R0(%r15)
 688        mvc     __PT_R15(4,%r15),__LC_SAVE_AREA_RESTART
 689        mvc     __PT_PSW(8,%r15),__LC_RST_OLD_PSW # store restart old psw
 690        ahi     %r15,-STACK_FRAME_OVERHEAD      # create stack frame on stack
 691        xc      0(STACK_FRAME_OVERHEAD,%r15),0(%r15)
 692        l       %r1,__LC_RESTART_FN             # load fn, parm & source cpu
 693        l       %r2,__LC_RESTART_DATA
 694        l       %r3,__LC_RESTART_SOURCE
 695        ltr     %r3,%r3                         # test source cpu address
 696        jm      1f                              # negative -> skip source stop
 6970:      sigp    %r4,%r3,SIGP_SENSE              # sigp sense to source cpu
 698        brc     10,0b                           # wait for status stored
 6991:      basr    %r14,%r1                        # call function
 700        stap    __SF_EMPTY(%r15)                # store cpu address
 701        lh      %r3,__SF_EMPTY(%r15)
 7022:      sigp    %r4,%r3,SIGP_STOP               # sigp stop to current cpu
 703        brc     2,2b
 7043:      j       3b
 705
 706        .section .kprobes.text, "ax"
 707
 708#ifdef CONFIG_CHECK_STACK
 709/*
 710 * The synchronous or the asynchronous stack overflowed. We are dead.
 711 * No need to properly save the registers, we are going to panic anyway.
 712 * Setup a pt_regs so that show_trace can provide a good call trace.
 713 */
 714stack_overflow:
 715        l       %r15,__LC_PANIC_STACK   # change to panic stack
 716        la      %r11,STACK_FRAME_OVERHEAD(%r15)
 717        stm     %r0,%r7,__PT_R0(%r11)
 718        stm     %r8,%r9,__PT_PSW(%r11)
 719        mvc     __PT_R8(32,%r11),0(%r14)
 720        l       %r1,BASED(1f)
 721        xc      __SF_BACKCHAIN(4,%r15),__SF_BACKCHAIN(%r15)
 722        lr      %r2,%r11                # pass pointer to pt_regs
 723        br      %r1                     # branch to kernel_stack_overflow
 7241:      .long   kernel_stack_overflow
 725#endif
 726
 727cleanup_table:
 728        .long   system_call + 0x80000000
 729        .long   sysc_do_svc + 0x80000000
 730        .long   sysc_tif + 0x80000000
 731        .long   sysc_restore + 0x80000000
 732        .long   sysc_done + 0x80000000
 733        .long   io_tif + 0x80000000
 734        .long   io_restore + 0x80000000
 735        .long   io_done + 0x80000000
 736        .long   psw_idle + 0x80000000
 737        .long   psw_idle_end + 0x80000000
 738
 739cleanup_critical:
 740        cl      %r9,BASED(cleanup_table)        # system_call
 741        jl      0f
 742        cl      %r9,BASED(cleanup_table+4)      # sysc_do_svc
 743        jl      cleanup_system_call
 744        cl      %r9,BASED(cleanup_table+8)      # sysc_tif
 745        jl      0f
 746        cl      %r9,BASED(cleanup_table+12)     # sysc_restore
 747        jl      cleanup_sysc_tif
 748        cl      %r9,BASED(cleanup_table+16)     # sysc_done
 749        jl      cleanup_sysc_restore
 750        cl      %r9,BASED(cleanup_table+20)     # io_tif
 751        jl      0f
 752        cl      %r9,BASED(cleanup_table+24)     # io_restore
 753        jl      cleanup_io_tif
 754        cl      %r9,BASED(cleanup_table+28)     # io_done
 755        jl      cleanup_io_restore
 756        cl      %r9,BASED(cleanup_table+32)     # psw_idle
 757        jl      0f
 758        cl      %r9,BASED(cleanup_table+36)     # psw_idle_end
 759        jl      cleanup_idle
 7600:      br      %r14
 761
 762cleanup_system_call:
 763        # check if stpt has been executed
 764        cl      %r9,BASED(cleanup_system_call_insn)
 765        jh      0f
 766        mvc     __LC_SYNC_ENTER_TIMER(8),__LC_ASYNC_ENTER_TIMER
 767        chi     %r11,__LC_SAVE_AREA_ASYNC
 768        je      0f
 769        mvc     __LC_SYNC_ENTER_TIMER(8),__LC_MCCK_ENTER_TIMER
 7700:      # check if stm has been executed
 771        cl      %r9,BASED(cleanup_system_call_insn+4)
 772        jh      0f
 773        mvc     __LC_SAVE_AREA_SYNC(32),0(%r11)
 7740:      # set up saved registers r12, and r13
 775        st      %r12,16(%r11)           # r12 thread-info pointer
 776        st      %r13,20(%r11)           # r13 literal-pool pointer
 777        # check if the user time calculation has been done
 778        cl      %r9,BASED(cleanup_system_call_insn+8)
 779        jh      0f
 780        l       %r10,__LC_EXIT_TIMER
 781        l       %r15,__LC_EXIT_TIMER+4
 782        SUB64   %r10,%r15,__LC_SYNC_ENTER_TIMER
 783        ADD64   %r10,%r15,__LC_USER_TIMER
 784        st      %r10,__LC_USER_TIMER
 785        st      %r15,__LC_USER_TIMER+4
 7860:      # check if the system time calculation has been done
 787        cl      %r9,BASED(cleanup_system_call_insn+12)
 788        jh      0f
 789        l       %r10,__LC_LAST_UPDATE_TIMER
 790        l       %r15,__LC_LAST_UPDATE_TIMER+4
 791        SUB64   %r10,%r15,__LC_EXIT_TIMER
 792        ADD64   %r10,%r15,__LC_SYSTEM_TIMER
 793        st      %r10,__LC_SYSTEM_TIMER
 794        st      %r15,__LC_SYSTEM_TIMER+4
 7950:      # update accounting time stamp
 796        mvc     __LC_LAST_UPDATE_TIMER(8),__LC_SYNC_ENTER_TIMER
 797        # set up saved register 11
 798        l       %r15,__LC_KERNEL_STACK
 799        la      %r9,STACK_FRAME_OVERHEAD(%r15)
 800        st      %r9,12(%r11)            # r11 pt_regs pointer
 801        # fill pt_regs
 802        mvc     __PT_R8(32,%r9),__LC_SAVE_AREA_SYNC
 803        stm     %r0,%r7,__PT_R0(%r9)
 804        mvc     __PT_PSW(8,%r9),__LC_SVC_OLD_PSW
 805        mvc     __PT_INT_CODE(4,%r9),__LC_SVC_ILC
 806        # setup saved register 15
 807        st      %r15,28(%r11)           # r15 stack pointer
 808        # set new psw address and exit
 809        l       %r9,BASED(cleanup_table+4)      # sysc_do_svc + 0x80000000
 810        br      %r14
 811cleanup_system_call_insn:
 812        .long   system_call + 0x80000000
 813        .long   sysc_stm + 0x80000000
 814        .long   sysc_vtime + 0x80000000 + 36
 815        .long   sysc_vtime + 0x80000000 + 76
 816
 817cleanup_sysc_tif:
 818        l       %r9,BASED(cleanup_table+8)      # sysc_tif + 0x80000000
 819        br      %r14
 820
 821cleanup_sysc_restore:
 822        cl      %r9,BASED(cleanup_sysc_restore_insn)
 823        jhe     0f
 824        l       %r9,12(%r11)            # get saved pointer to pt_regs
 825        mvc     __LC_RETURN_PSW(8),__PT_PSW(%r9)
 826        mvc     0(32,%r11),__PT_R8(%r9)
 827        lm      %r0,%r7,__PT_R0(%r9)
 8280:      lm      %r8,%r9,__LC_RETURN_PSW
 829        br      %r14
 830cleanup_sysc_restore_insn:
 831        .long   sysc_done - 4 + 0x80000000
 832
 833cleanup_io_tif:
 834        l       %r9,BASED(cleanup_table+20)     # io_tif + 0x80000000
 835        br      %r14
 836
 837cleanup_io_restore:
 838        cl      %r9,BASED(cleanup_io_restore_insn)
 839        jhe     0f
 840        l       %r9,12(%r11)            # get saved r11 pointer to pt_regs
 841        mvc     __LC_RETURN_PSW(8),__PT_PSW(%r9)
 842        mvc     0(32,%r11),__PT_R8(%r9)
 843        lm      %r0,%r7,__PT_R0(%r9)
 8440:      lm      %r8,%r9,__LC_RETURN_PSW
 845        br      %r14
 846cleanup_io_restore_insn:
 847        .long   io_done - 4 + 0x80000000
 848
 849cleanup_idle:
 850        # copy interrupt clock & cpu timer
 851        mvc     __CLOCK_IDLE_EXIT(8,%r2),__LC_INT_CLOCK
 852        mvc     __TIMER_IDLE_EXIT(8,%r2),__LC_ASYNC_ENTER_TIMER
 853        chi     %r11,__LC_SAVE_AREA_ASYNC
 854        je      0f
 855        mvc     __CLOCK_IDLE_EXIT(8,%r2),__LC_MCCK_CLOCK
 856        mvc     __TIMER_IDLE_EXIT(8,%r2),__LC_MCCK_ENTER_TIMER
 8570:      # check if stck has been executed
 858        cl      %r9,BASED(cleanup_idle_insn)
 859        jhe     1f
 860        mvc     __CLOCK_IDLE_ENTER(8,%r2),__CLOCK_IDLE_EXIT(%r2)
 861        mvc     __TIMER_IDLE_ENTER(8,%r2),__TIMER_IDLE_EXIT(%r3)
 8621:      # account system time going idle
 863        lm      %r9,%r10,__LC_STEAL_TIMER
 864        ADD64   %r9,%r10,__CLOCK_IDLE_ENTER(%r2)
 865        SUB64   %r9,%r10,__LC_LAST_UPDATE_CLOCK
 866        stm     %r9,%r10,__LC_STEAL_TIMER
 867        mvc     __LC_LAST_UPDATE_CLOCK(8),__CLOCK_IDLE_EXIT(%r2)
 868        lm      %r9,%r10,__LC_SYSTEM_TIMER
 869        ADD64   %r9,%r10,__LC_LAST_UPDATE_TIMER
 870        SUB64   %r9,%r10,__TIMER_IDLE_ENTER(%r2)
 871        stm     %r9,%r10,__LC_SYSTEM_TIMER
 872        mvc     __LC_LAST_UPDATE_TIMER(8),__TIMER_IDLE_EXIT(%r2)
 873        # prepare return psw
 874        n       %r8,BASED(cleanup_idle_wait)    # clear wait state bit
 875        l       %r9,24(%r11)                    # return from psw_idle
 876        br      %r14
 877cleanup_idle_insn:
 878        .long   psw_idle_lpsw + 0x80000000
 879cleanup_idle_wait:
 880        .long   0xfffdffff
 881
 882/*
 883 * Integer constants
 884 */
 885        .align  4
 886.Lnr_syscalls:
 887        .long   NR_syscalls
 888.Lvtimer_max:
 889        .quad   0x7fffffffffffffff
 890
 891/*
 892 * Symbol constants
 893 */
 894.Ldo_machine_check:     .long   s390_do_machine_check
 895.Lhandle_mcck:          .long   s390_handle_mcck
 896.Ldo_IRQ:               .long   do_IRQ
 897.Ldo_extint:            .long   do_extint
 898.Ldo_signal:            .long   do_signal
 899.Ldo_notify_resume:     .long   do_notify_resume
 900.Ldo_per_trap:          .long   do_per_trap
 901.Ljump_table:           .long   pgm_check_table
 902.Lschedule:             .long   schedule
 903#ifdef CONFIG_PREEMPT
 904.Lpreempt_irq:          .long   preempt_schedule_irq
 905#endif
 906.Ltrace_enter:          .long   do_syscall_trace_enter
 907.Ltrace_exit:           .long   do_syscall_trace_exit
 908.Lschedule_tail:        .long   schedule_tail
 909.Lsysc_per:             .long   sysc_per + 0x80000000
 910#ifdef CONFIG_TRACE_IRQFLAGS
 911.Lhardirqs_on:          .long   trace_hardirqs_on_caller
 912.Lhardirqs_off:         .long   trace_hardirqs_off_caller
 913#endif
 914#ifdef CONFIG_LOCKDEP
 915.Llockdep_sys_exit:     .long   lockdep_sys_exit
 916#endif
 917.Lcritical_start:       .long   __critical_start + 0x80000000
 918.Lcritical_length:      .long   __critical_end - __critical_start
 919
 920                .section .rodata, "a"
 921#define SYSCALL(esa,esame,emu)  .long esa
 922        .globl  sys_call_table
 923sys_call_table:
 924#include "syscalls.S"
 925#undef SYSCALL
 926