arch/s390/kernel/entry64.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/processor.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>
  20 #include <asm/page.h>
  21 #include <asm/sigp.h>
  22
  23 __PT_R0      =  __PT_GPRS
  24 __PT_R1      =  __PT_GPRS + 8
  25 __PT_R2      =  __PT_GPRS + 16
  26 __PT_R3      =  __PT_GPRS + 24
  27 __PT_R4      =  __PT_GPRS + 32
  28 __PT_R5      =  __PT_GPRS + 40
  29 __PT_R6      =  __PT_GPRS + 48
  30 __PT_R7      =  __PT_GPRS + 56
  31 __PT_R8      =  __PT_GPRS + 64
  32 __PT_R9      =  __PT_GPRS + 72
  33 __PT_R10     =  __PT_GPRS + 80
  34 __PT_R11     =  __PT_GPRS + 88
  35 __PT_R12     =  __PT_GPRS + 96
  36 __PT_R13     =  __PT_GPRS + 104
  37 __PT_R14     =  __PT_GPRS + 112
  38 __PT_R15     =  __PT_GPRS + 120
  39
  40 STACK_SHIFT = PAGE_SHIFT + THREAD_ORDER
  41 STACK_SIZE  = 1 << STACK_SHIFT
  42
  43 _TIF_WORK_SVC = (_TIF_SIGPENDING | _TIF_NOTIFY_RESUME | _TIF_NEED_RESCHED | \
  44                  _TIF_MCCK_PENDING | _TIF_PER_TRAP )
  45 _TIF_WORK_INT = (_TIF_SIGPENDING | _TIF_NOTIFY_RESUME | _TIF_NEED_RESCHED | \
  46                  _TIF_MCCK_PENDING)
  47 _TIF_TRACE    = (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | _TIF_SECCOMP | \
  48                  _TIF_SYSCALL_TRACEPOINT)
  49 _TIF_EXIT_SIE = (_TIF_SIGPENDING | _TIF_NEED_RESCHED | _TIF_MCCK_PENDING)
  50
  51 #define BASED(name) name-system_call(%r13)
  52
  53         .macro  TRACE_IRQS_ON
  54 #ifdef CONFIG_TRACE_IRQFLAGS
  55         basr    %r2,%r0
  56         brasl   %r14,trace_hardirqs_on_caller
  57 #endif
  58         .endm
  59
  60         .macro  TRACE_IRQS_OFF
  61 #ifdef CONFIG_TRACE_IRQFLAGS
  62         basr    %r2,%r0
  63         brasl   %r14,trace_hardirqs_off_caller
  64 #endif
  65         .endm
  66
  67         .macro  LOCKDEP_SYS_EXIT
  68 #ifdef CONFIG_LOCKDEP
  69         tm      __PT_PSW+1(%r11),0x01   # returning to user ?
  70         jz      .+10
  71         brasl   %r14,lockdep_sys_exit
  72 #endif
  73         .endm
  74
  75         .macro SPP newpp
  76 #if defined(CONFIG_KVM) || defined(CONFIG_KVM_MODULE)
  77         tm      __LC_MACHINE_FLAGS+6,0x20       # MACHINE_FLAG_SPP
  78         jz      .+8
  79         .insn   s,0xb2800000,\newpp
  80 #endif
  81         .endm
  82
  83         .macro  HANDLE_SIE_INTERCEPT scratch,pgmcheck
  84 #if defined(CONFIG_KVM) || defined(CONFIG_KVM_MODULE)
  85         tmhh    %r8,0x0001              # interrupting from user ?
  86         jnz     .+42
  87         lgr     \scratch,%r9
  88         slg     \scratch,BASED(.Lsie_loop)
  89         clg     \scratch,BASED(.Lsie_length)
  90         .if     \pgmcheck
  91         # Some program interrupts are suppressing (e.g. protection).
  92         # We must also check the instruction after SIE in that case.
  93         # do_protection_exception will rewind to rewind_pad
  94         jh      .+22
  95         .else
  96         jhe     .+22
  97         .endif
  98         lg      %r9,BASED(.Lsie_loop)
  99         SPP     BASED(.Lhost_id)        # set host id
 100 #endif
 101         .endm
 102
 103         .macro  CHECK_STACK stacksize,savearea
 104 #ifdef CONFIG_CHECK_STACK
 105         tml     %r15,\stacksize - CONFIG_STACK_GUARD
 106         lghi    %r14,\savearea
 107         jz      stack_overflow
 108 #endif
 109         .endm
 110
 111         .macro  SWITCH_ASYNC savearea,stack,shift
 112         tmhh    %r8,0x0001              # interrupting from user ?
 113         jnz     1f
 114         lgr     %r14,%r9
 115         slg     %r14,BASED(.Lcritical_start)
 116         clg     %r14,BASED(.Lcritical_length)
 117         jhe     0f
 118         lghi    %r11,\savearea          # inside critical section, do cleanup
 119         brasl   %r14,cleanup_critical
 120         tmhh    %r8,0x0001              # retest problem state after cleanup
 121         jnz     1f
 122 0:      lg      %r14,\stack             # are we already on the target stack?
 123         slgr    %r14,%r15
 124         srag    %r14,%r14,\shift
 125         jnz     1f
 126         CHECK_STACK 1<<\shift,\savearea
 127         j       2f
 128 1:      lg      %r15,\stack             # load target stack
 129 2:      aghi    %r15,-(STACK_FRAME_OVERHEAD + __PT_SIZE)
 130         la      %r11,STACK_FRAME_OVERHEAD(%r15)
 131         .endm
 132
 133         .macro UPDATE_VTIME scratch,enter_timer
 134         lg      \scratch,__LC_EXIT_TIMER
 135         slg     \scratch,\enter_timer
 136         alg     \scratch,__LC_USER_TIMER
 137         stg     \scratch,__LC_USER_TIMER
 138         lg      \scratch,__LC_LAST_UPDATE_TIMER
 139         slg     \scratch,__LC_EXIT_TIMER
 140         alg     \scratch,__LC_SYSTEM_TIMER
 141         stg     \scratch,__LC_SYSTEM_TIMER
 142         mvc     __LC_LAST_UPDATE_TIMER(8),\enter_timer
 143         .endm
 144
 145         .macro  LAST_BREAK scratch
 146         srag    \scratch,%r10,23
 147         jz      .+10
 148         stg     %r10,__TI_last_break(%r12)
 149         .endm
 150
 151         .macro REENABLE_IRQS
 152         stg     %r8,__LC_RETURN_PSW
 153         ni      __LC_RETURN_PSW,0xbf
 154         ssm     __LC_RETURN_PSW
 155         .endm
 156
 157         .macro STCK savearea
 158 #ifdef CONFIG_HAVE_MARCH_Z9_109_FEATURES
 159         .insn   s,0xb27c0000,\savearea          # store clock fast
 160 #else
 161         .insn   s,0xb2050000,\savearea          # store clock
 162 #endif
 163         .endm
 164
 165         .section .kprobes.text, "ax"
 166
 167 /*
 168  * Scheduler resume function, called by switch_to
 169  *  gpr2 = (task_struct *) prev
 170  *  gpr3 = (task_struct *) next
 171  * Returns:
 172  *  gpr2 = prev
 173  */
 174 ENTRY(__switch_to)
 175         stmg    %r6,%r15,__SF_GPRS(%r15)        # store gprs of prev task
 176         stg     %r15,__THREAD_ksp(%r2)          # store kernel stack of prev
 177         lg      %r4,__THREAD_info(%r2)          # get thread_info of prev
 178         lg      %r5,__THREAD_info(%r3)          # get thread_info of next
 179         lgr     %r15,%r5
 180         aghi    %r15,STACK_SIZE                 # end of kernel stack of next
 181         stg     %r3,__LC_CURRENT                # store task struct of next
 182         stg     %r5,__LC_THREAD_INFO            # store thread info of next
 183         stg     %r15,__LC_KERNEL_STACK          # store end of kernel stack
 184         lctl    %c4,%c4,__TASK_pid(%r3)         # load pid to control reg. 4
 185         mvc     __LC_CURRENT_PID+4(4,%r0),__TASK_pid(%r3) # store pid of next
 186         lg      %r15,__THREAD_ksp(%r3)          # load kernel stack of next
 187         tm      __TI_flags+7(%r4),_TIF_MCCK_PENDING # machine check pending?
 188         jz      0f
 189         ni      __TI_flags+7(%r4),255-_TIF_MCCK_PENDING # clear flag in prev
 190         oi      __TI_flags+7(%r5),_TIF_MCCK_PENDING     # set it in next
 191 0:      lmg     %r6,%r15,__SF_GPRS(%r15)        # load gprs of next task
 192         br      %r14
 193
 194 __critical_start:
 195 /*
 196  * SVC interrupt handler routine. System calls are synchronous events and
 197  * are executed with interrupts enabled.
 198  */
 199
 200 ENTRY(system_call)
 201         stpt    __LC_SYNC_ENTER_TIMER
 202 sysc_stmg:
 203         stmg    %r8,%r15,__LC_SAVE_AREA_SYNC
 204         lg      %r10,__LC_LAST_BREAK
 205         lg      %r12,__LC_THREAD_INFO
 206         larl    %r13,system_call
 207 sysc_per:
 208         lg      %r15,__LC_KERNEL_STACK
 209         aghi    %r15,-(STACK_FRAME_OVERHEAD + __PT_SIZE)
 210         la      %r11,STACK_FRAME_OVERHEAD(%r15) # pointer to pt_regs
 211 sysc_vtime:
 212         UPDATE_VTIME %r13,__LC_SYNC_ENTER_TIMER
 213         LAST_BREAK %r13
 214         stmg    %r0,%r7,__PT_R0(%r11)
 215         mvc     __PT_R8(64,%r11),__LC_SAVE_AREA_SYNC
 216         mvc     __PT_PSW(16,%r11),__LC_SVC_OLD_PSW
 217         mvc     __PT_INT_CODE(4,%r11),__LC_SVC_ILC
 218 sysc_do_svc:
 219         oi      __TI_flags+7(%r12),_TIF_SYSCALL
 220         llgh    %r8,__PT_INT_CODE+2(%r11)
 221         slag    %r8,%r8,2                       # shift and test for svc 0
 222         jnz     sysc_nr_ok
 223         # svc 0: system call number in %r1
 224         llgfr   %r1,%r1                         # clear high word in r1
 225         cghi    %r1,NR_syscalls
 226         jnl     sysc_nr_ok
 227         sth     %r1,__PT_INT_CODE+2(%r11)
 228         slag    %r8,%r1,2
 229 sysc_nr_ok:
 230         larl    %r10,sys_call_table             # 64 bit system call table
 231 #ifdef CONFIG_COMPAT
 232         tm      __TI_flags+5(%r12),(_TIF_31BIT>>16)
 233         jno     sysc_noemu
 234         larl    %r10,sys_call_table_emu         # 31 bit system call table
 235 sysc_noemu:
 236 #endif
 237         xc      __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
 238         stg     %r2,__PT_ORIG_GPR2(%r11)
 239         stg     %r7,STACK_FRAME_OVERHEAD(%r15)
 240         lgf     %r9,0(%r8,%r10)                 # get system call add.
 241         tm      __TI_flags+6(%r12),_TIF_TRACE >> 8
 242         jnz     sysc_tracesys
 243         basr    %r14,%r9                        # call sys_xxxx
 244         stg     %r2,__PT_R2(%r11)               # store return value
 245
 246 sysc_return:
 247         LOCKDEP_SYS_EXIT
 248 sysc_tif:
 249         tm      __PT_PSW+1(%r11),0x01           # returning to user ?
 250         jno     sysc_restore
 251         tm      __TI_flags+7(%r12),_TIF_WORK_SVC
 252         jnz     sysc_work                       # check for work
 253         ni      __TI_flags+7(%r12),255-_TIF_SYSCALL
 254 sysc_restore:
 255         lg      %r14,__LC_VDSO_PER_CPU
 256         lmg     %r0,%r10,__PT_R0(%r11)
 257         mvc     __LC_RETURN_PSW(16),__PT_PSW(%r11)
 258         stpt    __LC_EXIT_TIMER
 259         mvc     __VDSO_ECTG_BASE(16,%r14),__LC_EXIT_TIMER
 260         lmg     %r11,%r15,__PT_R11(%r11)
 261         lpswe   __LC_RETURN_PSW
 262 sysc_done:
 263
 264 #
 265 # One of the work bits is on. Find out which one.
 266 #
 267 sysc_work:
 268         tm      __TI_flags+7(%r12),_TIF_MCCK_PENDING
 269         jo      sysc_mcck_pending
 270         tm      __TI_flags+7(%r12),_TIF_NEED_RESCHED
 271         jo      sysc_reschedule
 272         tm      __TI_flags+7(%r12),_TIF_PER_TRAP
 273         jo      sysc_singlestep
 274         tm      __TI_flags+7(%r12),_TIF_SIGPENDING
 275         jo      sysc_sigpending
 276         tm      __TI_flags+7(%r12),_TIF_NOTIFY_RESUME
 277         jo      sysc_notify_resume
 278         j       sysc_return             # beware of critical section cleanup
 279
 280 #
 281 # _TIF_NEED_RESCHED is set, call schedule
 282 #
 283 sysc_reschedule:
 284         larl    %r14,sysc_return
 285         jg      schedule
 286
 287 #
 288 # _TIF_MCCK_PENDING is set, call handler
 289 #
 290 sysc_mcck_pending:
 291         larl    %r14,sysc_return
 292         jg      s390_handle_mcck        # TIF bit will be cleared by handler
 293
 294 #
 295 # _TIF_SIGPENDING is set, call do_signal
 296 #
 297 sysc_sigpending:
 298         lgr     %r2,%r11                # pass pointer to pt_regs
 299         brasl   %r14,do_signal
 300         tm      __TI_flags+7(%r12),_TIF_SYSCALL
 301         jno     sysc_return
 302         lmg     %r2,%r7,__PT_R2(%r11)   # load svc arguments
 303         lghi    %r8,0                   # svc 0 returns -ENOSYS
 304         llgh    %r1,__PT_INT_CODE+2(%r11)       # load new svc number
 305         cghi    %r1,NR_syscalls
 306         jnl     sysc_nr_ok              # invalid svc number -> do svc 0
 307         slag    %r8,%r1,2
 308         j       sysc_nr_ok              # restart svc
 309
 310 #
 311 # _TIF_NOTIFY_RESUME is set, call do_notify_resume
 312 #
 313 sysc_notify_resume:
 314         lgr     %r2,%r11                # pass pointer to pt_regs
 315         larl    %r14,sysc_return
 316         jg      do_notify_resume
 317
 318 #
 319 # _TIF_PER_TRAP is set, call do_per_trap
 320 #
 321 sysc_singlestep:
 322         ni      __TI_flags+7(%r12),255-_TIF_PER_TRAP
 323         lgr     %r2,%r11                # pass pointer to pt_regs
 324         larl    %r14,sysc_return
 325         jg      do_per_trap
 326
 327 #
 328 # call tracehook_report_syscall_entry/tracehook_report_syscall_exit before
 329 # and after the system call
 330 #
 331 sysc_tracesys:
 332         lgr     %r2,%r11                # pass pointer to pt_regs
 333         la      %r3,0
 334         llgh    %r0,__PT_INT_CODE+2(%r11)
 335         stg     %r0,__PT_R2(%r11)
 336         brasl   %r14,do_syscall_trace_enter
 337         lghi    %r0,NR_syscalls
 338         clgr    %r0,%r2
 339         jnh     sysc_tracenogo
 340         sllg    %r8,%r2,2
 341         lgf     %r9,0(%r8,%r10)
 342 sysc_tracego:
 343         lmg     %r3,%r7,__PT_R3(%r11)
 344         stg     %r7,STACK_FRAME_OVERHEAD(%r15)
 345         lg      %r2,__PT_ORIG_GPR2(%r11)
 346         basr    %r14,%r9                # call sys_xxx
 347         stg     %r2,__PT_R2(%r11)       # store return value
 348 sysc_tracenogo:
 349         tm      __TI_flags+6(%r12),_TIF_TRACE >> 8
 350         jz      sysc_return
 351         lgr     %r2,%r11                # pass pointer to pt_regs
 352         larl    %r14,sysc_return
 353         jg      do_syscall_trace_exit
 354
 355 #
 356 # a new process exits the kernel with ret_from_fork
 357 #
 358 ENTRY(ret_from_fork)
 359         la      %r11,STACK_FRAME_OVERHEAD(%r15)
 360         lg      %r12,__LC_THREAD_INFO
 361         brasl   %r14,schedule_tail
 362         TRACE_IRQS_ON
 363         ssm     __LC_SVC_NEW_PSW        # reenable interrupts
 364         tm      __PT_PSW+1(%r11),0x01   # forking a kernel thread ?
 365         jne     sysc_tracenogo
 366         # it's a kernel thread
 367         lmg     %r9,%r10,__PT_R9(%r11)  # load gprs
 368 ENTRY(kernel_thread_starter)
 369         la      %r2,0(%r10)
 370         basr    %r14,%r9
 371         j       sysc_tracenogo
 372
 373 /*
 374  * Program check handler routine
 375  */
 376
 377 ENTRY(pgm_check_handler)
 378         stpt    __LC_SYNC_ENTER_TIMER
 379         stmg    %r8,%r15,__LC_SAVE_AREA_SYNC
 380         lg      %r10,__LC_LAST_BREAK
 381         lg      %r12,__LC_THREAD_INFO
 382         larl    %r13,system_call
 383         lmg     %r8,%r9,__LC_PGM_OLD_PSW
 384         HANDLE_SIE_INTERCEPT %r14,1
 385         tmhh    %r8,0x0001              # test problem state bit
 386         jnz     1f                      # -> fault in user space
 387         tmhh    %r8,0x4000              # PER bit set in old PSW ?
 388         jnz     0f                      # -> enabled, can't be a double fault
 389         tm      __LC_PGM_ILC+3,0x80     # check for per exception
 390         jnz     pgm_svcper              # -> single stepped svc
 391 0:      CHECK_STACK STACK_SIZE,__LC_SAVE_AREA_SYNC
 392         j       2f
 393 1:      UPDATE_VTIME %r14,__LC_SYNC_ENTER_TIMER
 394         LAST_BREAK %r14
 395         lg      %r15,__LC_KERNEL_STACK
 396         lg      %r14,__TI_task(%r12)
 397         lghi    %r13,__LC_PGM_TDB
 398         tm      __LC_PGM_ILC+2,0x02     # check for transaction abort
 399         jz      2f
 400         mvc     __THREAD_trap_tdb(256,%r14),0(%r13)
 401 2:      aghi    %r15,-(STACK_FRAME_OVERHEAD + __PT_SIZE)
 402         la      %r11,STACK_FRAME_OVERHEAD(%r15)
 403         stmg    %r0,%r7,__PT_R0(%r11)
 404         mvc     __PT_R8(64,%r11),__LC_SAVE_AREA_SYNC
 405         stmg    %r8,%r9,__PT_PSW(%r11)
 406         mvc     __PT_INT_CODE(4,%r11),__LC_PGM_ILC
 407         mvc     __PT_INT_PARM_LONG(8,%r11),__LC_TRANS_EXC_CODE
 408         stg     %r10,__PT_ARGS(%r11)
 409         tm      __LC_PGM_ILC+3,0x80     # check for per exception
 410         jz      0f
 411         tmhh    %r8,0x0001              # kernel per event ?
 412         jz      pgm_kprobe
 413         oi      __TI_flags+7(%r12),_TIF_PER_TRAP
 414         mvc     __THREAD_per_address(8,%r14),__LC_PER_ADDRESS
 415         mvc     __THREAD_per_cause(2,%r14),__LC_PER_CAUSE
 416         mvc     __THREAD_per_paid(1,%r14),__LC_PER_PAID
 417 0:      REENABLE_IRQS
 418         xc      __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
 419         larl    %r1,pgm_check_table
 420         llgh    %r10,__PT_INT_CODE+2(%r11)
 421         nill    %r10,0x007f
 422         sll     %r10,2
 423         je      sysc_return
 424         lgf     %r1,0(%r10,%r1)         # load address of handler routine
 425         lgr     %r2,%r11                # pass pointer to pt_regs
 426         basr    %r14,%r1                # branch to interrupt-handler
 427         j       sysc_return
 428
 429 #
 430 # PER event in supervisor state, must be kprobes
 431 #
 432 pgm_kprobe:
 433         REENABLE_IRQS
 434         xc      __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
 435         lgr     %r2,%r11                # pass pointer to pt_regs
 436         brasl   %r14,do_per_trap
 437         j       sysc_return
 438
 439 #
 440 # single stepped system call
 441 #
 442 pgm_svcper:
 443         oi      __TI_flags+7(%r12),_TIF_PER_TRAP
 444         mvc     __LC_RETURN_PSW(8),__LC_SVC_NEW_PSW
 445         larl    %r14,sysc_per
 446         stg     %r14,__LC_RETURN_PSW+8
 447         lpswe   __LC_RETURN_PSW         # branch to sysc_per and enable irqs
 448
 449 /*
 450  * IO interrupt handler routine
 451  */
 452 ENTRY(io_int_handler)
 453         STCK    __LC_INT_CLOCK
 454         stpt    __LC_ASYNC_ENTER_TIMER
 455         stmg    %r8,%r15,__LC_SAVE_AREA_ASYNC
 456         lg      %r10,__LC_LAST_BREAK
 457         lg      %r12,__LC_THREAD_INFO
 458         larl    %r13,system_call
 459         lmg     %r8,%r9,__LC_IO_OLD_PSW
 460         HANDLE_SIE_INTERCEPT %r14,0
 461         SWITCH_ASYNC __LC_SAVE_AREA_ASYNC,__LC_ASYNC_STACK,STACK_SHIFT
 462         tmhh    %r8,0x0001              # interrupting from user?
 463         jz      io_skip
 464         UPDATE_VTIME %r14,__LC_ASYNC_ENTER_TIMER
 465         LAST_BREAK %r14
 466 io_skip:
 467         stmg    %r0,%r7,__PT_R0(%r11)
 468         mvc     __PT_R8(64,%r11),__LC_SAVE_AREA_ASYNC
 469         stmg    %r8,%r9,__PT_PSW(%r11)
 470         TRACE_IRQS_OFF
 471         xc      __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
 472         lgr     %r2,%r11                # pass pointer to pt_regs
 473         brasl   %r14,do_IRQ
 474 io_return:
 475         LOCKDEP_SYS_EXIT
 476         TRACE_IRQS_ON
 477 io_tif:
 478         tm      __TI_flags+7(%r12),_TIF_WORK_INT
 479         jnz     io_work                 # there is work to do (signals etc.)
 480 io_restore:
 481         lg      %r14,__LC_VDSO_PER_CPU
 482         lmg     %r0,%r10,__PT_R0(%r11)
 483         mvc     __LC_RETURN_PSW(16),__PT_PSW(%r11)
 484         stpt    __LC_EXIT_TIMER
 485         mvc     __VDSO_ECTG_BASE(16,%r14),__LC_EXIT_TIMER
 486         lmg     %r11,%r15,__PT_R11(%r11)
 487         lpswe   __LC_RETURN_PSW
 488 io_done:
 489
 490 #
 491 # There is work todo, find out in which context we have been interrupted:
 492 # 1) if we return to user space we can do all _TIF_WORK_INT work
 493 # 2) if we return to kernel code and kvm is enabled check if we need to
 494 #    modify the psw to leave SIE
 495 # 3) if we return to kernel code and preemptive scheduling is enabled check
 496 #    the preemption counter and if it is zero call preempt_schedule_irq
 497 # Before any work can be done, a switch to the kernel stack is required.
 498 #
 499 io_work:
 500         tm      __PT_PSW+1(%r11),0x01   # returning to user ?
 501         jo      io_work_user            # yes -> do resched & signal
 502 #ifdef CONFIG_PREEMPT
 503         # check for preemptive scheduling
 504         icm     %r0,15,__TI_precount(%r12)
 505         jnz     io_restore              # preemption is disabled
 506         tm      __TI_flags+7(%r12),_TIF_NEED_RESCHED
 507         jno     io_restore
 508         # switch to kernel stack
 509         lg      %r1,__PT_R15(%r11)
 510         aghi    %r1,-(STACK_FRAME_OVERHEAD + __PT_SIZE)
 511         mvc     STACK_FRAME_OVERHEAD(__PT_SIZE,%r1),0(%r11)
 512         xc      __SF_BACKCHAIN(8,%r1),__SF_BACKCHAIN(%r1)
 513         la      %r11,STACK_FRAME_OVERHEAD(%r1)
 514         lgr     %r15,%r1
 515         # TRACE_IRQS_ON already done at io_return, call
 516         # TRACE_IRQS_OFF to keep things symmetrical
 517         TRACE_IRQS_OFF
 518         brasl   %r14,preempt_schedule_irq
 519         j       io_return
 520 #else
 521         j       io_restore
 522 #endif
 523
 524 #
 525 # Need to do work before returning to userspace, switch to kernel stack
 526 #
 527 io_work_user:
 528         lg      %r1,__LC_KERNEL_STACK
 529         aghi    %r1,-(STACK_FRAME_OVERHEAD + __PT_SIZE)
 530         mvc     STACK_FRAME_OVERHEAD(__PT_SIZE,%r1),0(%r11)
 531         xc      __SF_BACKCHAIN(8,%r1),__SF_BACKCHAIN(%r1)
 532         la      %r11,STACK_FRAME_OVERHEAD(%r1)
 533         lgr     %r15,%r1
 534
 535 #
 536 # One of the work bits is on. Find out which one.
 537 # Checked are: _TIF_SIGPENDING, _TIF_NOTIFY_RESUME, _TIF_NEED_RESCHED
 538 #              and _TIF_MCCK_PENDING
 539 #
 540 io_work_tif:
 541         tm      __TI_flags+7(%r12),_TIF_MCCK_PENDING
 542         jo      io_mcck_pending
 543         tm      __TI_flags+7(%r12),_TIF_NEED_RESCHED
 544         jo      io_reschedule
 545         tm      __TI_flags+7(%r12),_TIF_SIGPENDING
 546         jo      io_sigpending
 547         tm      __TI_flags+7(%r12),_TIF_NOTIFY_RESUME
 548         jo      io_notify_resume
 549         j       io_return               # beware of critical section cleanup
 550
 551 #
 552 # _TIF_MCCK_PENDING is set, call handler
 553 #
 554 io_mcck_pending:
 555         # TRACE_IRQS_ON already done at io_return
 556         brasl   %r14,s390_handle_mcck   # TIF bit will be cleared by handler
 557         TRACE_IRQS_OFF
 558         j       io_return
 559
 560 #
 561 # _TIF_NEED_RESCHED is set, call schedule
 562 #
 563 io_reschedule:
 564         # TRACE_IRQS_ON already done at io_return
 565         ssm     __LC_SVC_NEW_PSW        # reenable interrupts
 566         brasl   %r14,schedule           # call scheduler
 567         ssm     __LC_PGM_NEW_PSW        # disable I/O and ext. interrupts
 568         TRACE_IRQS_OFF
 569         j       io_return
 570
 571 #
 572 # _TIF_SIGPENDING or is set, call do_signal
 573 #
 574 io_sigpending:
 575         # TRACE_IRQS_ON already done at io_return
 576         ssm     __LC_SVC_NEW_PSW        # reenable interrupts
 577         lgr     %r2,%r11                # pass pointer to pt_regs
 578         brasl   %r14,do_signal
 579         ssm     __LC_PGM_NEW_PSW        # disable I/O and ext. interrupts
 580         TRACE_IRQS_OFF
 581         j       io_return
 582
 583 #
 584 # _TIF_NOTIFY_RESUME or is set, call do_notify_resume
 585 #
 586 io_notify_resume:
 587         # TRACE_IRQS_ON already done at io_return
 588         ssm     __LC_SVC_NEW_PSW        # reenable interrupts
 589         lgr     %r2,%r11                # pass pointer to pt_regs
 590         brasl   %r14,do_notify_resume
 591         ssm     __LC_PGM_NEW_PSW        # disable I/O and ext. interrupts
 592         TRACE_IRQS_OFF
 593         j       io_return
 594
 595 /*
 596  * External interrupt handler routine
 597  */
 598 ENTRY(ext_int_handler)
 599         STCK    __LC_INT_CLOCK
 600         stpt    __LC_ASYNC_ENTER_TIMER
 601         stmg    %r8,%r15,__LC_SAVE_AREA_ASYNC
 602         lg      %r10,__LC_LAST_BREAK
 603         lg      %r12,__LC_THREAD_INFO
 604         larl    %r13,system_call
 605         lmg     %r8,%r9,__LC_EXT_OLD_PSW
 606         HANDLE_SIE_INTERCEPT %r14,0
 607         SWITCH_ASYNC __LC_SAVE_AREA_ASYNC,__LC_ASYNC_STACK,STACK_SHIFT
 608         tmhh    %r8,0x0001              # interrupting from user ?
 609         jz      ext_skip
 610         UPDATE_VTIME %r14,__LC_ASYNC_ENTER_TIMER
 611         LAST_BREAK %r14
 612 ext_skip:
 613         stmg    %r0,%r7,__PT_R0(%r11)
 614         mvc     __PT_R8(64,%r11),__LC_SAVE_AREA_ASYNC
 615         stmg    %r8,%r9,__PT_PSW(%r11)
 616         TRACE_IRQS_OFF
 617         xc      __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
 618         lghi    %r1,4096
 619         lgr     %r2,%r11                # pass pointer to pt_regs
 620         llgf    %r3,__LC_EXT_CPU_ADDR   # get cpu address + interruption code
 621         llgf    %r4,__LC_EXT_PARAMS     # get external parameter
 622         lg      %r5,__LC_EXT_PARAMS2-4096(%r1)  # get 64 bit external parameter
 623         brasl   %r14,do_extint
 624         j       io_return
 625
 626 /*
 627  * Load idle PSW. The second "half" of this function is in cleanup_idle.
 628  */
 629 ENTRY(psw_idle)
 630         stg     %r3,__SF_EMPTY(%r15)
 631         larl    %r1,psw_idle_lpsw+4
 632         stg     %r1,__SF_EMPTY+8(%r15)
 633         STCK    __CLOCK_IDLE_ENTER(%r2)
 634         stpt    __TIMER_IDLE_ENTER(%r2)
 635 psw_idle_lpsw:
 636         lpswe   __SF_EMPTY(%r15)
 637         br      %r14
 638 psw_idle_end:
 639
 640 __critical_end:
 641
 642 /*
 643  * Machine check handler routines
 644  */
 645 ENTRY(mcck_int_handler)
 646         STCK    __LC_MCCK_CLOCK
 647         la      %r1,4095                # revalidate r1
 648         spt     __LC_CPU_TIMER_SAVE_AREA-4095(%r1)      # revalidate cpu timer
 649         lmg     %r0,%r15,__LC_GPREGS_SAVE_AREA-4095(%r1)# revalidate gprs
 650         lg      %r10,__LC_LAST_BREAK
 651         lg      %r12,__LC_THREAD_INFO
 652         larl    %r13,system_call
 653         lmg     %r8,%r9,__LC_MCK_OLD_PSW
 654         HANDLE_SIE_INTERCEPT %r14,0
 655         tm      __LC_MCCK_CODE,0x80     # system damage?
 656         jo      mcck_panic              # yes -> rest of mcck code invalid
 657         lghi    %r14,__LC_CPU_TIMER_SAVE_AREA
 658         mvc     __LC_MCCK_ENTER_TIMER(8),0(%r14)
 659         tm      __LC_MCCK_CODE+5,0x02   # stored cpu timer value valid?
 660         jo      3f
 661         la      %r14,__LC_SYNC_ENTER_TIMER
 662         clc     0(8,%r14),__LC_ASYNC_ENTER_TIMER
 663         jl      0f
 664         la      %r14,__LC_ASYNC_ENTER_TIMER
 665 0:      clc     0(8,%r14),__LC_EXIT_TIMER
 666         jl      1f
 667         la      %r14,__LC_EXIT_TIMER
 668 1:      clc     0(8,%r14),__LC_LAST_UPDATE_TIMER
 669         jl      2f
 670         la      %r14,__LC_LAST_UPDATE_TIMER
 671 2:      spt     0(%r14)
 672         mvc     __LC_MCCK_ENTER_TIMER(8),0(%r14)
 673 3:      tm      __LC_MCCK_CODE+2,0x09   # mwp + ia of old psw valid?
 674         jno     mcck_panic              # no -> skip cleanup critical
 675         SWITCH_ASYNC __LC_GPREGS_SAVE_AREA+64,__LC_PANIC_STACK,PAGE_SHIFT
 676         tm      %r8,0x0001              # interrupting from user ?
 677         jz      mcck_skip
 678         UPDATE_VTIME %r14,__LC_MCCK_ENTER_TIMER
 679         LAST_BREAK %r14
 680 mcck_skip:
 681         lghi    %r14,__LC_GPREGS_SAVE_AREA
 682         mvc     __PT_R0(128,%r11),0(%r14)
 683         stmg    %r8,%r9,__PT_PSW(%r11)
 684         xc      __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
 685         lgr     %r2,%r11                # pass pointer to pt_regs
 686         brasl   %r14,s390_do_machine_check
 687         tm      __PT_PSW+1(%r11),0x01   # returning to user ?
 688         jno     mcck_return
 689         lg      %r1,__LC_KERNEL_STACK   # switch to kernel stack
 690         aghi    %r1,-(STACK_FRAME_OVERHEAD + __PT_SIZE)
 691         mvc     STACK_FRAME_OVERHEAD(__PT_SIZE,%r1),0(%r11)
 692         xc      __SF_BACKCHAIN(8,%r1),__SF_BACKCHAIN(%r1)
 693         la      %r11,STACK_FRAME_OVERHEAD(%r1)
 694         lgr     %r15,%r1
 695         ssm     __LC_PGM_NEW_PSW        # turn dat on, keep irqs off
 696         tm      __TI_flags+7(%r12),_TIF_MCCK_PENDING
 697         jno     mcck_return
 698         TRACE_IRQS_OFF
 699         brasl   %r14,s390_handle_mcck
 700         TRACE_IRQS_ON
 701 mcck_return:
 702         lg      %r14,__LC_VDSO_PER_CPU
 703         lmg     %r0,%r10,__PT_R0(%r11)
 704         mvc     __LC_RETURN_MCCK_PSW(16),__PT_PSW(%r11) # move return PSW
 705         tm      __LC_RETURN_MCCK_PSW+1,0x01 # returning to user ?
 706         jno     0f
 707         stpt    __LC_EXIT_TIMER
 708         mvc     __VDSO_ECTG_BASE(16,%r14),__LC_EXIT_TIMER
 709 0:      lmg     %r11,%r15,__PT_R11(%r11)
 710         lpswe   __LC_RETURN_MCCK_PSW
 711
 712 mcck_panic:
 713         lg      %r14,__LC_PANIC_STACK
 714         slgr    %r14,%r15
 715         srag    %r14,%r14,PAGE_SHIFT
 716         jz      0f
 717         lg      %r15,__LC_PANIC_STACK
 718 0:      aghi    %r15,-(STACK_FRAME_OVERHEAD + __PT_SIZE)
 719         j       mcck_skip
 720
 721 #
 722 # PSW restart interrupt handler
 723 #
 724 ENTRY(restart_int_handler)
 725         stg     %r15,__LC_SAVE_AREA_RESTART
 726         lg      %r15,__LC_RESTART_STACK
 727         aghi    %r15,-__PT_SIZE                 # create pt_regs on stack
 728         xc      0(__PT_SIZE,%r15),0(%r15)
 729         stmg    %r0,%r14,__PT_R0(%r15)
 730         mvc     __PT_R15(8,%r15),__LC_SAVE_AREA_RESTART
 731         mvc     __PT_PSW(16,%r15),__LC_RST_OLD_PSW # store restart old psw
 732         aghi    %r15,-STACK_FRAME_OVERHEAD      # create stack frame on stack
 733         xc      0(STACK_FRAME_OVERHEAD,%r15),0(%r15)
 734         lg      %r1,__LC_RESTART_FN             # load fn, parm & source cpu
 735         lg      %r2,__LC_RESTART_DATA
 736         lg      %r3,__LC_RESTART_SOURCE
 737         ltgr    %r3,%r3                         # test source cpu address
 738         jm      1f                              # negative -> skip source stop
 739 0:      sigp    %r4,%r3,SIGP_SENSE              # sigp sense to source cpu
 740         brc     10,0b                           # wait for status stored
 741 1:      basr    %r14,%r1                        # call function
 742         stap    __SF_EMPTY(%r15)                # store cpu address
 743         llgh    %r3,__SF_EMPTY(%r15)
 744 2:      sigp    %r4,%r3,SIGP_STOP               # sigp stop to current cpu
 745         brc     2,2b
 746 3:      j       3b
 747
 748         .section .kprobes.text, "ax"
 749
 750 #ifdef CONFIG_CHECK_STACK
 751 /*
 752  * The synchronous or the asynchronous stack overflowed. We are dead.
 753  * No need to properly save the registers, we are going to panic anyway.
 754  * Setup a pt_regs so that show_trace can provide a good call trace.
 755  */
 756 stack_overflow:
 757         lg      %r11,__LC_PANIC_STACK   # change to panic stack
 758         aghi    %r11,-__PT_SIZE         # create pt_regs
 759         stmg    %r0,%r7,__PT_R0(%r11)
 760         stmg    %r8,%r9,__PT_PSW(%r11)
 761         mvc     __PT_R8(64,%r11),0(%r14)
 762         stg     %r10,__PT_ORIG_GPR2(%r11) # store last break to orig_gpr2
 763         lgr     %r15,%r11
 764         aghi    %r15,-STACK_FRAME_OVERHEAD
 765         xc      __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
 766         lgr     %r2,%r11                # pass pointer to pt_regs
 767         jg      kernel_stack_overflow
 768 #endif
 769
 770         .align  8
 771 cleanup_table:
 772         .quad   system_call
 773         .quad   sysc_do_svc
 774         .quad   sysc_tif
 775         .quad   sysc_restore
 776         .quad   sysc_done
 777         .quad   io_tif
 778         .quad   io_restore
 779         .quad   io_done
 780         .quad   psw_idle
 781         .quad   psw_idle_end
 782
 783 cleanup_critical:
 784         clg     %r9,BASED(cleanup_table)        # system_call
 785         jl      0f
 786         clg     %r9,BASED(cleanup_table+8)      # sysc_do_svc
 787         jl      cleanup_system_call
 788         clg     %r9,BASED(cleanup_table+16)     # sysc_tif
 789         jl      0f
 790         clg     %r9,BASED(cleanup_table+24)     # sysc_restore
 791         jl      cleanup_sysc_tif
 792         clg     %r9,BASED(cleanup_table+32)     # sysc_done
 793         jl      cleanup_sysc_restore
 794         clg     %r9,BASED(cleanup_table+40)     # io_tif
 795         jl      0f
 796         clg     %r9,BASED(cleanup_table+48)     # io_restore
 797         jl      cleanup_io_tif
 798         clg     %r9,BASED(cleanup_table+56)     # io_done
 799         jl      cleanup_io_restore
 800         clg     %r9,BASED(cleanup_table+64)     # psw_idle
 801         jl      0f
 802         clg     %r9,BASED(cleanup_table+72)     # psw_idle_end
 803         jl      cleanup_idle
 804 0:      br      %r14
 805
 806
 807 cleanup_system_call:
 808         # check if stpt has been executed
 809         clg     %r9,BASED(cleanup_system_call_insn)
 810         jh      0f
 811         mvc     __LC_SYNC_ENTER_TIMER(8),__LC_ASYNC_ENTER_TIMER
 812         cghi    %r11,__LC_SAVE_AREA_ASYNC
 813         je      0f
 814         mvc     __LC_SYNC_ENTER_TIMER(8),__LC_MCCK_ENTER_TIMER
 815 0:      # check if stmg has been executed
 816         clg     %r9,BASED(cleanup_system_call_insn+8)
 817         jh      0f
 818         mvc     __LC_SAVE_AREA_SYNC(64),0(%r11)
 819 0:      # check if base register setup + TIF bit load has been done
 820         clg     %r9,BASED(cleanup_system_call_insn+16)
 821         jhe     0f
 822         # set up saved registers r10 and r12
 823         stg     %r10,16(%r11)           # r10 last break
 824         stg     %r12,32(%r11)           # r12 thread-info pointer
 825 0:      # check if the user time update has been done
 826         clg     %r9,BASED(cleanup_system_call_insn+24)
 827         jh      0f
 828         lg      %r15,__LC_EXIT_TIMER
 829         slg     %r15,__LC_SYNC_ENTER_TIMER
 830         alg     %r15,__LC_USER_TIMER
 831         stg     %r15,__LC_USER_TIMER
 832 0:      # check if the system time update has been done
 833         clg     %r9,BASED(cleanup_system_call_insn+32)
 834         jh      0f
 835         lg      %r15,__LC_LAST_UPDATE_TIMER
 836         slg     %r15,__LC_EXIT_TIMER
 837         alg     %r15,__LC_SYSTEM_TIMER
 838         stg     %r15,__LC_SYSTEM_TIMER
 839 0:      # update accounting time stamp
 840         mvc     __LC_LAST_UPDATE_TIMER(8),__LC_SYNC_ENTER_TIMER
 841         # do LAST_BREAK
 842         lg      %r9,16(%r11)
 843         srag    %r9,%r9,23
 844         jz      0f
 845         mvc     __TI_last_break(8,%r12),16(%r11)
 846 0:      # set up saved register r11
 847         lg      %r15,__LC_KERNEL_STACK
 848         aghi    %r15,-__PT_SIZE
 849         stg     %r15,24(%r11)           # r11 pt_regs pointer
 850         # fill pt_regs
 851         mvc     __PT_R8(64,%r15),__LC_SAVE_AREA_SYNC
 852         stmg    %r0,%r7,__PT_R0(%r15)
 853         mvc     __PT_PSW(16,%r15),__LC_SVC_OLD_PSW
 854         mvc     __PT_INT_CODE(4,%r15),__LC_SVC_ILC
 855         # setup saved register r15
 856         aghi    %r15,-STACK_FRAME_OVERHEAD
 857         stg     %r15,56(%r11)           # r15 stack pointer
 858         # set new psw address and exit
 859         larl    %r9,sysc_do_svc
 860         br      %r14
 861 cleanup_system_call_insn:
 862         .quad   system_call
 863         .quad   sysc_stmg
 864         .quad   sysc_per
 865         .quad   sysc_vtime+18
 866         .quad   sysc_vtime+42
 867
 868 cleanup_sysc_tif:
 869         larl    %r9,sysc_tif
 870         br      %r14
 871
 872 cleanup_sysc_restore:
 873         clg     %r9,BASED(cleanup_sysc_restore_insn)
 874         je      0f
 875         lg      %r9,24(%r11)            # get saved pointer to pt_regs
 876         mvc     __LC_RETURN_PSW(16),__PT_PSW(%r9)
 877         mvc     0(64,%r11),__PT_R8(%r9)
 878         lmg     %r0,%r7,__PT_R0(%r9)
 879 0:      lmg     %r8,%r9,__LC_RETURN_PSW
 880         br      %r14
 881 cleanup_sysc_restore_insn:
 882         .quad   sysc_done - 4
 883
 884 cleanup_io_tif:
 885         larl    %r9,io_tif
 886         br      %r14
 887
 888 cleanup_io_restore:
 889         clg     %r9,BASED(cleanup_io_restore_insn)
 890         je      0f
 891         lg      %r9,24(%r11)            # get saved r11 pointer to pt_regs
 892         mvc     __LC_RETURN_PSW(16),__PT_PSW(%r9)
 893         mvc     0(64,%r11),__PT_R8(%r9)
 894         lmg     %r0,%r7,__PT_R0(%r9)
 895 0:      lmg     %r8,%r9,__LC_RETURN_PSW
 896         br      %r14
 897 cleanup_io_restore_insn:
 898         .quad   io_done - 4
 899
 900 cleanup_idle:
 901         # copy interrupt clock & cpu timer
 902         mvc     __CLOCK_IDLE_EXIT(8,%r2),__LC_INT_CLOCK
 903         mvc     __TIMER_IDLE_EXIT(8,%r2),__LC_ASYNC_ENTER_TIMER
 904         cghi    %r11,__LC_SAVE_AREA_ASYNC
 905         je      0f
 906         mvc     __CLOCK_IDLE_EXIT(8,%r2),__LC_MCCK_CLOCK
 907         mvc     __TIMER_IDLE_EXIT(8,%r2),__LC_MCCK_ENTER_TIMER
 908 0:      # check if stck & stpt have been executed
 909         clg     %r9,BASED(cleanup_idle_insn)
 910         jhe     1f
 911         mvc     __CLOCK_IDLE_ENTER(8,%r2),__CLOCK_IDLE_EXIT(%r2)
 912         mvc     __TIMER_IDLE_ENTER(8,%r2),__TIMER_IDLE_EXIT(%r2)
 913 1:      # account system time going idle
 914         lg      %r9,__LC_STEAL_TIMER
 915         alg     %r9,__CLOCK_IDLE_ENTER(%r2)
 916         slg     %r9,__LC_LAST_UPDATE_CLOCK
 917         stg     %r9,__LC_STEAL_TIMER
 918         mvc     __LC_LAST_UPDATE_CLOCK(8),__CLOCK_IDLE_EXIT(%r2)
 919         lg      %r9,__LC_SYSTEM_TIMER
 920         alg     %r9,__LC_LAST_UPDATE_TIMER
 921         slg     %r9,__TIMER_IDLE_ENTER(%r2)
 922         stg     %r9,__LC_SYSTEM_TIMER
 923         mvc     __LC_LAST_UPDATE_TIMER(8),__TIMER_IDLE_EXIT(%r2)
 924         # prepare return psw
 925         nihh    %r8,0xfffd              # clear wait state bit
 926         lg      %r9,48(%r11)            # return from psw_idle
 927         br      %r14
 928 cleanup_idle_insn:
 929         .quad   psw_idle_lpsw
 930
 931 /*
 932  * Integer constants
 933  */
 934         .align  8
 935 .Lcritical_start:
 936         .quad   __critical_start
 937 .Lcritical_length:
 938         .quad   __critical_end - __critical_start
 939
 940
 941 #if defined(CONFIG_KVM) || defined(CONFIG_KVM_MODULE)
 942 /*
 943  * sie64a calling convention:
 944  * %r2 pointer to sie control block
 945  * %r3 guest register save area
 946  */
 947 ENTRY(sie64a)
 948         stmg    %r6,%r14,__SF_GPRS(%r15)        # save kernel registers
 949         stg     %r2,__SF_EMPTY(%r15)            # save control block pointer
 950         stg     %r3,__SF_EMPTY+8(%r15)          # save guest register save area
 951         xc      __SF_EMPTY+16(8,%r15),__SF_EMPTY+16(%r15) # host id == 0
 952         lmg     %r0,%r13,0(%r3)                 # load guest gprs 0-13
 953 # some program checks are suppressing. C code (e.g. do_protection_exception)
 954 # will rewind the PSW by the ILC, which is 4 bytes in case of SIE. Other
 955 # instructions in the sie_loop should not cause program interrupts. So
 956 # lets use a nop (47 00 00 00) as a landing pad.
 957 # See also HANDLE_SIE_INTERCEPT
 958 rewind_pad:
 959         nop     0
 960 sie_loop:
 961         lg      %r14,__LC_THREAD_INFO           # pointer thread_info struct
 962         tm      __TI_flags+7(%r14),_TIF_EXIT_SIE
 963         jnz     sie_exit
 964         lg      %r14,__LC_GMAP                  # get gmap pointer
 965         ltgr    %r14,%r14
 966         jz      sie_gmap
 967         lctlg   %c1,%c1,__GMAP_ASCE(%r14)       # load primary asce
 968 sie_gmap:
 969         lg      %r14,__SF_EMPTY(%r15)           # get control block pointer
 970         SPP     __SF_EMPTY(%r15)                # set guest id
 971         sie     0(%r14)
 972 sie_done:
 973         SPP     __SF_EMPTY+16(%r15)             # set host id
 974         lg      %r14,__LC_THREAD_INFO           # pointer thread_info struct
 975 sie_exit:
 976         lctlg   %c1,%c1,__LC_USER_ASCE          # load primary asce
 977         lg      %r14,__SF_EMPTY+8(%r15)         # load guest register save area
 978         stmg    %r0,%r13,0(%r14)                # save guest gprs 0-13
 979         lmg     %r6,%r14,__SF_GPRS(%r15)        # restore kernel registers
 980         lghi    %r2,0
 981         br      %r14
 982 sie_fault:
 983         lctlg   %c1,%c1,__LC_USER_ASCE          # load primary asce
 984         lg      %r14,__LC_THREAD_INFO           # pointer thread_info struct
 985         lg      %r14,__SF_EMPTY+8(%r15)         # load guest register save area
 986         stmg    %r0,%r13,0(%r14)                # save guest gprs 0-13
 987         lmg     %r6,%r14,__SF_GPRS(%r15)        # restore kernel registers
 988         lghi    %r2,-EFAULT
 989         br      %r14
 990
 991         .align  8
 992 .Lsie_loop:
 993         .quad   sie_loop
 994 .Lsie_length:
 995         .quad   sie_done - sie_loop
 996 .Lhost_id:
 997         .quad   0
 998
 999         EX_TABLE(rewind_pad,sie_fault)
1000         EX_TABLE(sie_loop,sie_fault)
1001 #endif
1002
1003                 .section .rodata, "a"
1004 #define SYSCALL(esa,esame,emu)  .long esame
1005         .globl  sys_call_table
1006 sys_call_table:
1007 #include "syscalls.S"
1008 #undef SYSCALL
1009
1010 #ifdef CONFIG_COMPAT
1011
1012 #define SYSCALL(esa,esame,emu)  .long emu
1013 sys_call_table_emu:
1014 #include "syscalls.S"
1015 #undef SYSCALL
1016 #endif