arch/s390/kernel/entry64.S

   1 /*
   2  *  arch/s390/kernel/entry.S
   3  *    S390 low-level entry points.
   4  *
   5  *  S390 version
   6  *    Copyright (C) 1999,2000 IBM Deutschland Entwicklung GmbH, IBM Corporation
   7  *    Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
   8  *               Hartmut Penner (hp@de.ibm.com),
   9  *               Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com),
  10  */
  11
  12 #include <linux/sys.h>
  13 #include <linux/linkage.h>
  14 #include <linux/config.h>
  15 #include <asm/cache.h>
  16 #include <asm/lowcore.h>
  17 #include <asm/errno.h>
  18 #include <asm/ptrace.h>
  19 #include <asm/thread_info.h>
  20 #include <asm/offsets.h>
  21 #include <asm/unistd.h>
  22 #include <asm/page.h>
  23
  24 /*
  25  * Stack layout for the system_call stack entry.
  26  * The first few entries are identical to the user_regs_struct.
  27  */
  28 SP_PTREGS    =  STACK_FRAME_OVERHEAD
  29 SP_ARGS      =  STACK_FRAME_OVERHEAD + __PT_ARGS
  30 SP_PSW       =  STACK_FRAME_OVERHEAD + __PT_PSW
  31 SP_R0        =  STACK_FRAME_OVERHEAD + __PT_GPRS
  32 SP_R1        =  STACK_FRAME_OVERHEAD + __PT_GPRS + 8
  33 SP_R2        =  STACK_FRAME_OVERHEAD + __PT_GPRS + 16
  34 SP_R3        =  STACK_FRAME_OVERHEAD + __PT_GPRS + 24
  35 SP_R4        =  STACK_FRAME_OVERHEAD + __PT_GPRS + 32
  36 SP_R5        =  STACK_FRAME_OVERHEAD + __PT_GPRS + 40
  37 SP_R6        =  STACK_FRAME_OVERHEAD + __PT_GPRS + 48
  38 SP_R7        =  STACK_FRAME_OVERHEAD + __PT_GPRS + 56
  39 SP_R8        =  STACK_FRAME_OVERHEAD + __PT_GPRS + 64
  40 SP_R9        =  STACK_FRAME_OVERHEAD + __PT_GPRS + 72
  41 SP_R10       =  STACK_FRAME_OVERHEAD + __PT_GPRS + 80
  42 SP_R11       =  STACK_FRAME_OVERHEAD + __PT_GPRS + 88
  43 SP_R12       =  STACK_FRAME_OVERHEAD + __PT_GPRS + 96
  44 SP_R13       =  STACK_FRAME_OVERHEAD + __PT_GPRS + 104
  45 SP_R14       =  STACK_FRAME_OVERHEAD + __PT_GPRS + 112
  46 SP_R15       =  STACK_FRAME_OVERHEAD + __PT_GPRS + 120
  47 SP_ORIG_R2   =  STACK_FRAME_OVERHEAD + __PT_ORIG_GPR2
  48 SP_ILC       =  STACK_FRAME_OVERHEAD + __PT_ILC
  49 SP_TRAP      =  STACK_FRAME_OVERHEAD + __PT_TRAP
  50 SP_SIZE      =  STACK_FRAME_OVERHEAD + __PT_SIZE
  51
  52 STACK_SHIFT = PAGE_SHIFT + THREAD_ORDER
  53 STACK_SIZE  = 1 << STACK_SHIFT
  54
  55 _TIF_WORK_SVC = (_TIF_SIGPENDING | _TIF_NEED_RESCHED | \
  56                  _TIF_RESTART_SVC | _TIF_SINGLE_STEP )
  57 _TIF_WORK_INT = (_TIF_SIGPENDING | _TIF_NEED_RESCHED)
  58
  59 #define BASED(name) name-system_call(%r13)
  60
  61         .macro  STORE_TIMER lc_offset
  62 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
  63         stpt    \lc_offset
  64 #endif
  65         .endm
  66
  67 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
  68         .macro  UPDATE_VTIME lc_from,lc_to,lc_sum
  69         lg      %r10,\lc_from
  70         slg     %r10,\lc_to
  71         alg     %r10,\lc_sum
  72         stg     %r10,\lc_sum
  73         .endm
  74 #endif
  75
  76 /*
  77  * Register usage in interrupt handlers:
  78  *    R9  - pointer to current task structure
  79  *    R13 - pointer to literal pool
  80  *    R14 - return register for function calls
  81  *    R15 - kernel stack pointer
  82  */
  83
  84         .macro  SAVE_ALL_BASE savearea
  85         stmg    %r12,%r15,\savearea
  86         larl    %r13,system_call
  87         .endm
  88
  89         .macro  SAVE_ALL psworg,savearea,sync
  90         la      %r12,\psworg
  91         .if     \sync
  92         tm      \psworg+1,0x01          # test problem state bit
  93         jz      2f                      # skip stack setup save
  94         lg      %r15,__LC_KERNEL_STACK  # problem state -> load ksp
  95         .else
  96         tm      \psworg+1,0x01          # test problem state bit
  97         jnz     1f                      # from user -> load kernel stack
  98         clc     \psworg+8(8),BASED(.Lcritical_end)
  99         jhe     0f
 100         clc     \psworg+8(8),BASED(.Lcritical_start)
 101         jl      0f
 102         brasl   %r14,cleanup_critical
 103         tm      0(%r12),0x01            # retest problem state after cleanup
 104         jnz     1f
 105 0:      lg      %r14,__LC_ASYNC_STACK   # are we already on the async. stack ?
 106         slgr    %r14,%r15
 107         srag    %r14,%r14,STACK_SHIFT
 108         jz      2f
 109 1:      lg      %r15,__LC_ASYNC_STACK   # load async stack
 110         .endif
 111 #ifdef CONFIG_CHECK_STACK
 112         j       3f
 113 2:      tml     %r15,STACK_SIZE - CONFIG_STACK_GUARD
 114         jz      stack_overflow
 115 3:
 116 #endif
 117 2:      aghi    %r15,-SP_SIZE           # make room for registers & psw
 118         mvc     SP_PSW(16,%r15),0(%r12) # move user PSW to stack
 119         la      %r12,\psworg
 120         stg     %r2,SP_ORIG_R2(%r15)    # store original content of gpr 2
 121         icm     %r12,12,__LC_SVC_ILC
 122         stmg    %r0,%r11,SP_R0(%r15)    # store gprs %r0-%r11 to kernel stack
 123         st      %r12,SP_ILC(%r15)
 124         mvc     SP_R12(32,%r15),\savearea # move %r12-%r15 to stack
 125         la      %r12,0
 126         stg     %r12,__SF_BACKCHAIN(%r15)
 127         .endm
 128
 129         .macro  RESTORE_ALL sync
 130         mvc     __LC_RETURN_PSW(16),SP_PSW(%r15) # move user PSW to lowcore
 131         .if !\sync
 132         ni      __LC_RETURN_PSW+1,0xfd  # clear wait state bit
 133         .endif
 134         lmg     %r0,%r15,SP_R0(%r15)    # load gprs 0-15 of user
 135         STORE_TIMER __LC_EXIT_TIMER
 136         lpswe   __LC_RETURN_PSW         # back to caller
 137         .endm
 138
 139 /*
 140  * Scheduler resume function, called by switch_to
 141  *  gpr2 = (task_struct *) prev
 142  *  gpr3 = (task_struct *) next
 143  * Returns:
 144  *  gpr2 = prev
 145  */
 146         .globl  __switch_to
 147 __switch_to:
 148         tm      __THREAD_per+4(%r3),0xe8 # is the new process using per ?
 149         jz      __switch_to_noper               # if not we're fine
 150         stctg   %c9,%c11,__SF_EMPTY(%r15)# We are using per stuff
 151         clc     __THREAD_per(24,%r3),__SF_EMPTY(%r15)
 152         je      __switch_to_noper            # we got away without bashing TLB's
 153         lctlg   %c9,%c11,__THREAD_per(%r3)      # Nope we didn't
 154 __switch_to_noper:
 155         stmg    %r6,%r15,__SF_GPRS(%r15)# store __switch_to registers of prev task
 156         stg     %r15,__THREAD_ksp(%r2)  # store kernel stack to prev->tss.ksp
 157         lg      %r15,__THREAD_ksp(%r3)  # load kernel stack from next->tss.ksp
 158         lmg     %r6,%r15,__SF_GPRS(%r15)# load __switch_to registers of next task
 159         stg     %r3,__LC_CURRENT        # __LC_CURRENT = current task struct
 160         lctl    %c4,%c4,__TASK_pid(%r3) # load pid to control reg. 4
 161         lg      %r3,__THREAD_info(%r3)  # load thread_info from task struct
 162         stg     %r3,__LC_THREAD_INFO
 163         aghi    %r3,STACK_SIZE
 164         stg     %r3,__LC_KERNEL_STACK   # __LC_KERNEL_STACK = new kernel stack
 165         br      %r14
 166
 167 __critical_start:
 168 /*
 169  * SVC interrupt handler routine. System calls are synchronous events and
 170  * are executed with interrupts enabled.
 171  */
 172
 173         .globl  system_call
 174 system_call:
 175         STORE_TIMER __LC_SYNC_ENTER_TIMER
 176 sysc_saveall:
 177         SAVE_ALL_BASE __LC_SAVE_AREA
 178         SAVE_ALL __LC_SVC_OLD_PSW,__LC_SAVE_AREA,1
 179         llgh    %r7,__LC_SVC_INT_CODE # get svc number from lowcore
 180 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
 181 sysc_vtime:
 182         tm      SP_PSW+1(%r15),0x01     # interrupting from user ?
 183         jz      sysc_do_svc
 184         UPDATE_VTIME __LC_EXIT_TIMER,__LC_SYNC_ENTER_TIMER,__LC_USER_TIMER
 185 sysc_stime:
 186         UPDATE_VTIME __LC_LAST_UPDATE_TIMER,__LC_EXIT_TIMER,__LC_SYSTEM_TIMER
 187 sysc_update:
 188         mvc     __LC_LAST_UPDATE_TIMER(8),__LC_SYNC_ENTER_TIMER
 189 #endif
 190 sysc_do_svc:
 191         lg      %r9,__LC_THREAD_INFO    # load pointer to thread_info struct
 192         slag    %r7,%r7,2         # *4 and test for svc 0
 193         jnz     sysc_nr_ok
 194         # svc 0: system call number in %r1
 195         cl      %r1,BASED(.Lnr_syscalls)
 196         jnl     sysc_nr_ok
 197         lgfr    %r7,%r1           # clear high word in r1
 198         slag    %r7,%r7,2         # svc 0: system call number in %r1
 199 sysc_nr_ok:
 200         mvc     SP_ARGS(8,%r15),SP_R7(%r15)
 201 sysc_do_restart:
 202         larl    %r10,sys_call_table
 203 #ifdef CONFIG_S390_SUPPORT
 204         tm      SP_PSW+3(%r15),0x01  # are we running in 31 bit mode ?
 205         jo      sysc_noemu
 206         larl    %r10,sys_call_table_emu  # use 31 bit emulation system calls
 207 sysc_noemu:
 208 #endif
 209         tm      __TI_flags+7(%r9),(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT)
 210         lgf     %r8,0(%r7,%r10)   # load address of system call routine
 211         jnz     sysc_tracesys
 212         basr    %r14,%r8          # call sys_xxxx
 213         stg     %r2,SP_R2(%r15)   # store return value (change R2 on stack)
 214                                   # ATTENTION: check sys_execve_glue before
 215                                   # changing anything here !!
 216
 217 sysc_return:
 218         tm      SP_PSW+1(%r15),0x01    # returning to user ?
 219         jno     sysc_leave
 220         tm      __TI_flags+7(%r9),_TIF_WORK_SVC
 221         jnz     sysc_work         # there is work to do (signals etc.)
 222 sysc_leave:
 223         RESTORE_ALL 1
 224
 225 #
 226 # recheck if there is more work to do
 227 #
 228 sysc_work_loop:
 229         tm      __TI_flags+7(%r9),_TIF_WORK_SVC
 230         jz      sysc_leave        # there is no work to do
 231 #
 232 # One of the work bits is on. Find out which one.
 233 #
 234 sysc_work:
 235         tm      __TI_flags+7(%r9),_TIF_NEED_RESCHED
 236         jo      sysc_reschedule
 237         tm      __TI_flags+7(%r9),_TIF_SIGPENDING
 238         jo      sysc_sigpending
 239         tm      __TI_flags+7(%r9),_TIF_RESTART_SVC
 240         jo      sysc_restart
 241         tm      __TI_flags+7(%r9),_TIF_SINGLE_STEP
 242         jo      sysc_singlestep
 243         j       sysc_leave
 244
 245 #
 246 # _TIF_NEED_RESCHED is set, call schedule
 247 #
 248 sysc_reschedule:
 249         larl    %r14,sysc_work_loop
 250         jg      schedule            # return point is sysc_return
 251
 252 #
 253 # _TIF_SIGPENDING is set, call do_signal
 254 #
 255 sysc_sigpending:
 256         ni      __TI_flags+7(%r9),255-_TIF_SINGLE_STEP # clear TIF_SINGLE_STEP
 257         la      %r2,SP_PTREGS(%r15) # load pt_regs
 258         sgr     %r3,%r3           # clear *oldset
 259         brasl   %r14,do_signal    # call do_signal
 260         tm      __TI_flags+7(%r9),_TIF_RESTART_SVC
 261         jo      sysc_restart
 262         tm      __TI_flags+7(%r9),_TIF_SINGLE_STEP
 263         jo      sysc_singlestep
 264         j       sysc_leave        # out of here, do NOT recheck
 265
 266 #
 267 # _TIF_RESTART_SVC is set, set up registers and restart svc
 268 #
 269 sysc_restart:
 270         ni      __TI_flags+7(%r9),255-_TIF_RESTART_SVC # clear TIF_RESTART_SVC
 271         lg      %r7,SP_R2(%r15)        # load new svc number
 272         slag    %r7,%r7,2              # *4
 273         mvc     SP_R2(8,%r15),SP_ORIG_R2(%r15) # restore first argument
 274         lmg     %r2,%r6,SP_R2(%r15)    # load svc arguments
 275         j       sysc_do_restart        # restart svc
 276
 277 #
 278 # _TIF_SINGLE_STEP is set, call do_single_step
 279 #
 280 sysc_singlestep:
 281         ni      __TI_flags+7(%r9),255-_TIF_SINGLE_STEP # clear TIF_SINGLE_STEP
 282         lhi     %r0,__LC_PGM_OLD_PSW
 283         sth     %r0,SP_TRAP(%r15)       # set trap indication to pgm check
 284         la      %r2,SP_PTREGS(%r15)     # address of register-save area
 285         larl    %r14,sysc_return        # load adr. of system return
 286         jg      do_single_step          # branch to do_sigtrap
 287
 288
 289 __critical_end:
 290
 291 #
 292 # call syscall_trace before and after system call
 293 # special linkage: %r12 contains the return address for trace_svc
 294 #
 295 sysc_tracesys:
 296         la      %r2,SP_PTREGS(%r15)    # load pt_regs
 297         la      %r3,0
 298         srl     %r7,2
 299         stg     %r7,SP_R2(%r15)
 300         brasl   %r14,syscall_trace
 301         lghi    %r0,NR_syscalls
 302         clg     %r0,SP_R2(%r15)
 303         jnh     sysc_tracenogo
 304         lg      %r7,SP_R2(%r15)   # strace might have changed the
 305         sll     %r7,2             #  system call
 306         lgf     %r8,0(%r7,%r10)
 307 sysc_tracego:
 308         lmg     %r3,%r6,SP_R3(%r15)
 309         lg      %r2,SP_ORIG_R2(%r15)
 310         basr    %r14,%r8            # call sys_xxx
 311         stg     %r2,SP_R2(%r15)     # store return value
 312 sysc_tracenogo:
 313         tm      __TI_flags+7(%r9),(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT)
 314         jz      sysc_return
 315         la      %r2,SP_PTREGS(%r15)    # load pt_regs
 316         la      %r3,1
 317         larl    %r14,sysc_return    # return point is sysc_return
 318         jg      syscall_trace
 319
 320 #
 321 # a new process exits the kernel with ret_from_fork
 322 #
 323         .globl  ret_from_fork
 324 ret_from_fork:
 325         lg      %r13,__LC_SVC_NEW_PSW+8
 326         lg      %r9,__LC_THREAD_INFO    # load pointer to thread_info struct
 327         tm      SP_PSW+1(%r15),0x01     # forking a kernel thread ?
 328         jo      0f
 329         stg     %r15,SP_R15(%r15)       # store stack pointer for new kthread
 330 0:      brasl   %r14,schedule_tail
 331         stosm   24(%r15),0x03     # reenable interrupts
 332         j       sysc_return
 333
 334 #
 335 # clone, fork, vfork, exec and sigreturn need glue,
 336 # because they all expect pt_regs as parameter,
 337 # but are called with different parameter.
 338 # return-address is set up above
 339 #
 340 sys_clone_glue:
 341         la      %r2,SP_PTREGS(%r15)    # load pt_regs
 342         jg      sys_clone              # branch to sys_clone
 343
 344 #ifdef CONFIG_S390_SUPPORT
 345 sys32_clone_glue:
 346         la      %r2,SP_PTREGS(%r15)    # load pt_regs
 347         jg      sys32_clone            # branch to sys32_clone
 348 #endif
 349
 350 sys_fork_glue:
 351         la      %r2,SP_PTREGS(%r15)    # load pt_regs
 352         jg      sys_fork               # branch to sys_fork
 353
 354 sys_vfork_glue:
 355         la      %r2,SP_PTREGS(%r15)    # load pt_regs
 356         jg      sys_vfork              # branch to sys_vfork
 357
 358 sys_execve_glue:
 359         la      %r2,SP_PTREGS(%r15)   # load pt_regs
 360         lgr     %r12,%r14             # save return address
 361         brasl   %r14,sys_execve       # call sys_execve
 362         ltgr    %r2,%r2               # check if execve failed
 363         bnz     0(%r12)               # it did fail -> store result in gpr2
 364         b       6(%r12)               # SKIP STG 2,SP_R2(15) in
 365                                       # system_call/sysc_tracesys
 366 #ifdef CONFIG_S390_SUPPORT
 367 sys32_execve_glue:
 368         la      %r2,SP_PTREGS(%r15)   # load pt_regs
 369         lgr     %r12,%r14             # save return address
 370         brasl   %r14,sys32_execve     # call sys32_execve
 371         ltgr    %r2,%r2               # check if execve failed
 372         bnz     0(%r12)               # it did fail -> store result in gpr2
 373         b       6(%r12)               # SKIP STG 2,SP_R2(15) in
 374                                       # system_call/sysc_tracesys
 375 #endif
 376
 377 sys_sigreturn_glue:
 378         la      %r2,SP_PTREGS(%r15)   # load pt_regs as parameter
 379         jg      sys_sigreturn         # branch to sys_sigreturn
 380
 381 #ifdef CONFIG_S390_SUPPORT
 382 sys32_sigreturn_glue:
 383         la      %r2,SP_PTREGS(%r15)   # load pt_regs as parameter
 384         jg      sys32_sigreturn       # branch to sys32_sigreturn
 385 #endif
 386
 387 sys_rt_sigreturn_glue:
 388         la      %r2,SP_PTREGS(%r15)   # load pt_regs as parameter
 389         jg      sys_rt_sigreturn      # branch to sys_sigreturn
 390
 391 #ifdef CONFIG_S390_SUPPORT
 392 sys32_rt_sigreturn_glue:
 393         la      %r2,SP_PTREGS(%r15)   # load pt_regs as parameter
 394         jg      sys32_rt_sigreturn    # branch to sys32_sigreturn
 395 #endif
 396
 397 #
 398 # sigsuspend and rt_sigsuspend need pt_regs as an additional
 399 # parameter and they have to skip the store of %r2 into the
 400 # user register %r2 because the return value was set in
 401 # sigsuspend and rt_sigsuspend already and must not be overwritten!
 402 #
 403
 404 sys_sigsuspend_glue:
 405         lgr     %r5,%r4               # move mask back
 406         lgr     %r4,%r3               # move history1 parameter
 407         lgr     %r3,%r2               # move history0 parameter
 408         la      %r2,SP_PTREGS(%r15)   # load pt_regs as first parameter
 409         la      %r14,6(%r14)          # skip store of return value
 410         jg      sys_sigsuspend        # branch to sys_sigsuspend
 411
 412 #ifdef CONFIG_S390_SUPPORT
 413 sys32_sigsuspend_glue:
 414         llgfr   %r4,%r4               # unsigned long
 415         lgr     %r5,%r4               # move mask back
 416         lgfr    %r3,%r3               # int
 417         lgr     %r4,%r3               # move history1 parameter
 418         lgfr    %r2,%r2               # int
 419         lgr     %r3,%r2               # move history0 parameter
 420         la      %r2,SP_PTREGS(%r15)   # load pt_regs as first parameter
 421         la      %r14,6(%r14)          # skip store of return value
 422         jg      sys32_sigsuspend      # branch to sys32_sigsuspend
 423 #endif
 424
 425 sys_rt_sigsuspend_glue:
 426         lgr     %r4,%r3               # move sigsetsize parameter
 427         lgr     %r3,%r2               # move unewset parameter
 428         la      %r2,SP_PTREGS(%r15)   # load pt_regs as first parameter
 429         la      %r14,6(%r14)          # skip store of return value
 430         jg      sys_rt_sigsuspend     # branch to sys_rt_sigsuspend
 431
 432 #ifdef CONFIG_S390_SUPPORT
 433 sys32_rt_sigsuspend_glue:
 434         llgfr   %r3,%r3               # size_t
 435         lgr     %r4,%r3               # move sigsetsize parameter
 436         llgtr   %r2,%r2               # sigset_emu31_t *
 437         lgr     %r3,%r2               # move unewset parameter
 438         la      %r2,SP_PTREGS(%r15)   # load pt_regs as first parameter
 439         la      %r14,6(%r14)          # skip store of return value
 440         jg      sys32_rt_sigsuspend   # branch to sys32_rt_sigsuspend
 441 #endif
 442
 443 sys_sigaltstack_glue:
 444         la      %r4,SP_PTREGS(%r15)   # load pt_regs as parameter
 445         jg      sys_sigaltstack       # branch to sys_sigreturn
 446
 447 #ifdef CONFIG_S390_SUPPORT
 448 sys32_sigaltstack_glue:
 449         la      %r4,SP_PTREGS(%r15)   # load pt_regs as parameter
 450         jg      sys32_sigaltstack_wrapper # branch to sys_sigreturn
 451 #endif
 452
 453 /*
 454  * Program check handler routine
 455  */
 456
 457         .globl  pgm_check_handler
 458 pgm_check_handler:
 459 /*
 460  * First we need to check for a special case:
 461  * Single stepping an instruction that disables the PER event mask will
 462  * cause a PER event AFTER the mask has been set. Example: SVC or LPSW.
 463  * For a single stepped SVC the program check handler gets control after
 464  * the SVC new PSW has been loaded. But we want to execute the SVC first and
 465  * then handle the PER event. Therefore we update the SVC old PSW to point
 466  * to the pgm_check_handler and branch to the SVC handler after we checked
 467  * if we have to load the kernel stack register.
 468  * For every other possible cause for PER event without the PER mask set
 469  * we just ignore the PER event (FIXME: is there anything we have to do
 470  * for LPSW?).
 471  */
 472         STORE_TIMER __LC_SYNC_ENTER_TIMER
 473         SAVE_ALL_BASE __LC_SAVE_AREA
 474         tm      __LC_PGM_INT_CODE+1,0x80 # check whether we got a per exception
 475         jnz     pgm_per                  # got per exception -> special case
 476         SAVE_ALL __LC_PGM_OLD_PSW,__LC_SAVE_AREA,1
 477 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
 478         tm      SP_PSW+1(%r15),0x01     # interrupting from user ?
 479         jz      pgm_no_vtime
 480         UPDATE_VTIME __LC_EXIT_TIMER,__LC_SYNC_ENTER_TIMER,__LC_USER_TIMER
 481         UPDATE_VTIME __LC_LAST_UPDATE_TIMER,__LC_EXIT_TIMER,__LC_SYSTEM_TIMER
 482         mvc     __LC_LAST_UPDATE_TIMER(8),__LC_SYNC_ENTER_TIMER
 483 pgm_no_vtime:
 484 #endif
 485         lg      %r9,__LC_THREAD_INFO    # load pointer to thread_info struct
 486         lgf     %r3,__LC_PGM_ILC         # load program interruption code
 487         lghi    %r8,0x7f
 488         ngr     %r8,%r3
 489 pgm_do_call:
 490         sll     %r8,3
 491         larl    %r1,pgm_check_table
 492         lg      %r1,0(%r8,%r1)           # load address of handler routine
 493         la      %r2,SP_PTREGS(%r15)      # address of register-save area
 494         larl    %r14,sysc_return
 495         br      %r1                      # branch to interrupt-handler
 496
 497 #
 498 # handle per exception
 499 #
 500 pgm_per:
 501         tm      __LC_PGM_OLD_PSW,0x40    # test if per event recording is on
 502         jnz     pgm_per_std              # ok, normal per event from user space
 503 # ok its one of the special cases, now we need to find out which one
 504         clc     __LC_PGM_OLD_PSW(16),__LC_SVC_NEW_PSW
 505         je      pgm_svcper
 506 # no interesting special case, ignore PER event
 507         lmg     %r12,%r15,__LC_SAVE_AREA
 508         lpswe   __LC_PGM_OLD_PSW
 509
 510 #
 511 # Normal per exception
 512 #
 513 pgm_per_std:
 514         SAVE_ALL __LC_PGM_OLD_PSW,__LC_SAVE_AREA,1
 515 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
 516         tm      SP_PSW+1(%r15),0x01     # interrupting from user ?
 517         jz      pgm_no_vtime2
 518         UPDATE_VTIME __LC_EXIT_TIMER,__LC_SYNC_ENTER_TIMER,__LC_USER_TIMER
 519         UPDATE_VTIME __LC_LAST_UPDATE_TIMER,__LC_EXIT_TIMER,__LC_SYSTEM_TIMER
 520         mvc     __LC_LAST_UPDATE_TIMER(8),__LC_SYNC_ENTER_TIMER
 521 pgm_no_vtime2:
 522 #endif
 523         lg      %r9,__LC_THREAD_INFO    # load pointer to thread_info struct
 524         lg      %r1,__TI_task(%r9)
 525         mvc     __THREAD_per+__PER_atmid(2,%r1),__LC_PER_ATMID
 526         mvc     __THREAD_per+__PER_address(8,%r1),__LC_PER_ADDRESS
 527         mvc     __THREAD_per+__PER_access_id(1,%r1),__LC_PER_ACCESS_ID
 528         oi      __TI_flags+7(%r9),_TIF_SINGLE_STEP # set TIF_SINGLE_STEP
 529         lgf     %r3,__LC_PGM_ILC         # load program interruption code
 530         lghi    %r8,0x7f
 531         ngr     %r8,%r3                  # clear per-event-bit and ilc
 532         je      sysc_return
 533         j       pgm_do_call
 534
 535 #
 536 # it was a single stepped SVC that is causing all the trouble
 537 #
 538 pgm_svcper:
 539         SAVE_ALL __LC_SVC_OLD_PSW,__LC_SAVE_AREA,1
 540 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
 541         tm      SP_PSW+1(%r15),0x01     # interrupting from user ?
 542         jz      pgm_no_vtime3
 543         UPDATE_VTIME __LC_EXIT_TIMER,__LC_SYNC_ENTER_TIMER,__LC_USER_TIMER
 544         UPDATE_VTIME __LC_LAST_UPDATE_TIMER,__LC_EXIT_TIMER,__LC_SYSTEM_TIMER
 545         mvc     __LC_LAST_UPDATE_TIMER(8),__LC_SYNC_ENTER_TIMER
 546 pgm_no_vtime3:
 547 #endif
 548         llgh    %r7,__LC_SVC_INT_CODE   # get svc number from lowcore
 549         lg      %r9,__LC_THREAD_INFO    # load pointer to thread_info struct
 550         lg      %r1,__TI_task(%r9)
 551         mvc     __THREAD_per+__PER_atmid(2,%r1),__LC_PER_ATMID
 552         mvc     __THREAD_per+__PER_address(8,%r1),__LC_PER_ADDRESS
 553         mvc     __THREAD_per+__PER_access_id(1,%r1),__LC_PER_ACCESS_ID
 554         oi      __TI_flags+7(%r9),_TIF_SINGLE_STEP # set TIF_SINGLE_STEP
 555         stosm   __SF_EMPTY(%r15),0x03   # reenable interrupts
 556         j       sysc_do_svc
 557
 558 /*
 559  * IO interrupt handler routine
 560  */
 561         .globl io_int_handler
 562 io_int_handler:
 563         STORE_TIMER __LC_ASYNC_ENTER_TIMER
 564         stck    __LC_INT_CLOCK
 565         SAVE_ALL_BASE __LC_SAVE_AREA+32
 566         SAVE_ALL __LC_IO_OLD_PSW,__LC_SAVE_AREA+32,0
 567 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
 568         tm      SP_PSW+1(%r15),0x01     # interrupting from user ?
 569         jz      io_no_vtime
 570         UPDATE_VTIME __LC_EXIT_TIMER,__LC_ASYNC_ENTER_TIMER,__LC_USER_TIMER
 571         UPDATE_VTIME __LC_LAST_UPDATE_TIMER,__LC_EXIT_TIMER,__LC_SYSTEM_TIMER
 572         mvc     __LC_LAST_UPDATE_TIMER(8),__LC_ASYNC_ENTER_TIMER
 573 io_no_vtime:
 574 #endif
 575         lg      %r9,__LC_THREAD_INFO    # load pointer to thread_info struct
 576         la      %r2,SP_PTREGS(%r15)    # address of register-save area
 577         brasl   %r14,do_IRQ            # call standard irq handler
 578
 579 io_return:
 580         tm      SP_PSW+1(%r15),0x01    # returning to user ?
 581 #ifdef CONFIG_PREEMPT
 582         jno     io_preempt             # no -> check for preemptive scheduling
 583 #else
 584         jno     io_leave               # no-> skip resched & signal
 585 #endif
 586         tm      __TI_flags+7(%r9),_TIF_WORK_INT
 587         jnz     io_work                # there is work to do (signals etc.)
 588 io_leave:
 589         RESTORE_ALL 0
 590
 591 #ifdef CONFIG_PREEMPT
 592 io_preempt:
 593         icm     %r0,15,__TI_precount(%r9)
 594         jnz     io_leave
 595         # switch to kernel stack
 596         lg      %r1,SP_R15(%r15)
 597         aghi    %r1,-SP_SIZE
 598         mvc     SP_PTREGS(__PT_SIZE,%r1),SP_PTREGS(%r15)
 599         xc      __SF_BACKCHAIN(8,%r1),__SF_BACKCHAIN(%r1) # clear back chain
 600         lgr     %r15,%r1
 601 io_resume_loop:
 602         tm      __TI_flags+7(%r9),_TIF_NEED_RESCHED
 603         jno     io_leave
 604         larl    %r1,.Lc_pactive
 605         mvc     __TI_precount(4,%r9),0(%r1)
 606         stosm   __SF_EMPTY(%r15),0x03   # reenable interrupts
 607         brasl   %r14,schedule          # call schedule
 608         stnsm   __SF_EMPTY(%r15),0xfc   # disable I/O and ext. interrupts
 609         xc      __TI_precount(4,%r9),__TI_precount(%r9)
 610         j       io_resume_loop
 611 #endif
 612
 613 #
 614 # switch to kernel stack, then check TIF bits
 615 #
 616 io_work:
 617         lg      %r1,__LC_KERNEL_STACK
 618         aghi    %r1,-SP_SIZE
 619         mvc     SP_PTREGS(__PT_SIZE,%r1),SP_PTREGS(%r15)
 620         xc      __SF_BACKCHAIN(8,%r1),__SF_BACKCHAIN(%r1) # clear back chain
 621         lgr     %r15,%r1
 622 #
 623 # One of the work bits is on. Find out which one.
 624 # Checked are: _TIF_SIGPENDING and _TIF_NEED_RESCHED
 625 #
 626 io_work_loop:
 627         tm      __TI_flags+7(%r9),_TIF_NEED_RESCHED
 628         jo      io_reschedule
 629         tm      __TI_flags+7(%r9),_TIF_SIGPENDING
 630         jo      io_sigpending
 631         j       io_leave
 632
 633 #
 634 # _TIF_NEED_RESCHED is set, call schedule
 635 #
 636 io_reschedule:
 637         stosm   __SF_EMPTY(%r15),0x03   # reenable interrupts
 638         brasl   %r14,schedule           # call scheduler
 639         stnsm   __SF_EMPTY(%r15),0xfc   # disable I/O and ext. interrupts
 640         tm      __TI_flags+7(%r9),_TIF_WORK_INT
 641         jz      io_leave                # there is no work to do
 642         j       io_work_loop
 643
 644 #
 645 # _TIF_SIGPENDING is set, call do_signal
 646 #
 647 io_sigpending:
 648         stosm   __SF_EMPTY(%r15),0x03   # reenable interrupts
 649         la      %r2,SP_PTREGS(%r15)     # load pt_regs
 650         slgr    %r3,%r3                 # clear *oldset
 651         brasl   %r14,do_signal          # call do_signal
 652         stnsm   __SF_EMPTY(%r15),0xfc   # disable I/O and ext. interrupts
 653         j       sysc_leave              # out of here, do NOT recheck
 654
 655 /*
 656  * External interrupt handler routine
 657  */
 658         .globl  ext_int_handler
 659 ext_int_handler:
 660         STORE_TIMER __LC_ASYNC_ENTER_TIMER
 661         stck    __LC_INT_CLOCK
 662         SAVE_ALL_BASE __LC_SAVE_AREA+32
 663         SAVE_ALL __LC_EXT_OLD_PSW,__LC_SAVE_AREA+32,0
 664 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
 665         tm      SP_PSW+1(%r15),0x01     # interrupting from user ?
 666         jz      ext_no_vtime
 667         UPDATE_VTIME __LC_EXIT_TIMER,__LC_ASYNC_ENTER_TIMER,__LC_USER_TIMER
 668         UPDATE_VTIME __LC_LAST_UPDATE_TIMER,__LC_EXIT_TIMER,__LC_SYSTEM_TIMER
 669         mvc     __LC_LAST_UPDATE_TIMER(8),__LC_ASYNC_ENTER_TIMER
 670 ext_no_vtime:
 671 #endif
 672         lg      %r9,__LC_THREAD_INFO    # load pointer to thread_info struct
 673         la      %r2,SP_PTREGS(%r15)    # address of register-save area
 674         llgh    %r3,__LC_EXT_INT_CODE  # get interruption code
 675         brasl   %r14,do_extint
 676         j       io_return
 677
 678 /*
 679  * Machine check handler routines
 680  */
 681         .globl mcck_int_handler
 682 mcck_int_handler:
 683         STORE_TIMER __LC_ASYNC_ENTER_TIMER
 684         SAVE_ALL_BASE __LC_SAVE_AREA+64
 685         SAVE_ALL __LC_MCK_OLD_PSW,__LC_SAVE_AREA+64,0
 686 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
 687         tm      SP_PSW+1(%r15),0x01     # interrupting from user ?
 688         jz      mcck_no_vtime
 689         UPDATE_VTIME __LC_EXIT_TIMER,__LC_ASYNC_ENTER_TIMER,__LC_USER_TIMER
 690         UPDATE_VTIME __LC_LAST_UPDATE_TIMER,__LC_EXIT_TIMER,__LC_SYSTEM_TIMER
 691         mvc     __LC_LAST_UPDATE_TIMER(8),__LC_ASYNC_ENTER_TIMER
 692 mcck_no_vtime:
 693 #endif
 694         brasl   %r14,s390_do_machine_check
 695 mcck_return:
 696         RESTORE_ALL 0
 697
 698 #ifdef CONFIG_SMP
 699 /*
 700  * Restart interruption handler, kick starter for additional CPUs
 701  */
 702         .globl restart_int_handler
 703 restart_int_handler:
 704         lg      %r15,__LC_SAVE_AREA+120 # load ksp
 705         lghi    %r10,__LC_CREGS_SAVE_AREA
 706         lctlg   %c0,%c15,0(%r10) # get new ctl regs
 707         lghi    %r10,__LC_AREGS_SAVE_AREA
 708         lam     %a0,%a15,0(%r10)
 709         lmg     %r6,%r15,__SF_GPRS(%r15) # load registers from clone
 710         stosm   __SF_EMPTY(%r15),0x04    # now we can turn dat on
 711         jg      start_secondary
 712 #else
 713 /*
 714  * If we do not run with SMP enabled, let the new CPU crash ...
 715  */
 716         .globl restart_int_handler
 717 restart_int_handler:
 718         basr    %r1,0
 719 restart_base:
 720         lpswe   restart_crash-restart_base(%r1)
 721         .align 8
 722 restart_crash:
 723         .long  0x000a0000,0x00000000,0x00000000,0x00000000
 724 restart_go:
 725 #endif
 726
 727 #ifdef CONFIG_CHECK_STACK
 728 /*
 729  * The synchronous or the asynchronous stack overflowed. We are dead.
 730  * No need to properly save the registers, we are going to panic anyway.
 731  * Setup a pt_regs so that show_trace can provide a good call trace.
 732  */
 733 stack_overflow:
 734         lg      %r15,__LC_PANIC_STACK   # change to panic stack
 735         aghi    %r1,-SP_SIZE
 736         mvc     SP_PSW(16,%r15),0(%r12) # move user PSW to stack
 737         stmg    %r0,%r11,SP_R0(%r15)    # store gprs %r0-%r11 to kernel stack
 738         la      %r1,__LC_SAVE_AREA
 739         chi     %r12,__LC_SVC_OLD_PSW
 740         je      0f
 741         chi     %r12,__LC_PGM_OLD_PSW
 742         je      0f
 743         la      %r1,__LC_SAVE_AREA+16
 744 0:      mvc     SP_R12(32,%r15),0(%r1)  # move %r12-%r15 to stack
 745         xc      __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15) # clear back chain
 746         la      %r2,SP_PTREGS(%r15)     # load pt_regs
 747         jg      kernel_stack_overflow
 748 #endif
 749
 750 cleanup_table_system_call:
 751         .quad   system_call, sysc_do_svc
 752 cleanup_table_sysc_return:
 753         .quad   sysc_return, sysc_leave
 754 cleanup_table_sysc_leave:
 755         .quad   sysc_leave, sysc_work_loop
 756 cleanup_table_sysc_work_loop:
 757         .quad   sysc_work_loop, sysc_reschedule
 758
 759 cleanup_critical:
 760         clc     8(8,%r12),BASED(cleanup_table_system_call)
 761         jl      0f
 762         clc     8(8,%r12),BASED(cleanup_table_system_call+8)
 763         jl      cleanup_system_call
 764 0:
 765         clc     8(8,%r12),BASED(cleanup_table_sysc_return)
 766         jl      0f
 767         clc     8(8,%r12),BASED(cleanup_table_sysc_return+8)
 768         jl      cleanup_sysc_return
 769 0:
 770         clc     8(8,%r12),BASED(cleanup_table_sysc_leave)
 771         jl      0f
 772         clc     8(8,%r12),BASED(cleanup_table_sysc_leave+8)
 773         jl      cleanup_sysc_leave
 774 0:
 775         clc     8(8,%r12),BASED(cleanup_table_sysc_work_loop)
 776         jl      0f
 777         clc     8(8,%r12),BASED(cleanup_table_sysc_work_loop+8)
 778         jl      cleanup_sysc_leave
 779 0:
 780         br      %r14
 781
 782 cleanup_system_call:
 783         mvc     __LC_RETURN_PSW(16),0(%r12)
 784 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
 785         clc     __LC_RETURN_PSW+8(8),BASED(cleanup_system_call_insn+8)
 786         jh      0f
 787         mvc     __LC_SYNC_ENTER_TIMER(8),__LC_ASYNC_ENTER_TIMER
 788 0:      clc     __LC_RETURN_PSW+8(8),BASED(cleanup_system_call_insn+16)
 789         jhe     cleanup_vtime
 790 #endif
 791         clc     __LC_RETURN_PSW+8(8),BASED(cleanup_system_call_insn)
 792         jh      0f
 793         mvc     __LC_SAVE_AREA(32),__LC_SAVE_AREA+32
 794 0:      stg     %r13,__LC_SAVE_AREA+40
 795         SAVE_ALL __LC_SVC_OLD_PSW,__LC_SAVE_AREA,1
 796         stg     %r15,__LC_SAVE_AREA+56
 797         llgh    %r7,__LC_SVC_INT_CODE
 798 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
 799 cleanup_vtime:
 800         clc     __LC_RETURN_PSW+8(8),BASED(cleanup_system_call_insn+24)
 801         jhe     cleanup_stime
 802         tm      SP_PSW+1(%r15),0x01     # interrupting from user ?
 803         jz      cleanup_novtime
 804         UPDATE_VTIME __LC_EXIT_TIMER,__LC_SYNC_ENTER_TIMER,__LC_USER_TIMER
 805 cleanup_stime:
 806         clc     __LC_RETURN_PSW+8(8),BASED(cleanup_system_call_insn+32)
 807         jh      cleanup_update
 808         UPDATE_VTIME __LC_LAST_UPDATE_TIMER,__LC_EXIT_TIMER,__LC_SYSTEM_TIMER
 809 cleanup_update:
 810         mvc     __LC_LAST_UPDATE_TIMER(8),__LC_SYNC_ENTER_TIMER
 811 cleanup_novtime:
 812 #endif
 813         mvc     __LC_RETURN_PSW+8(8),BASED(cleanup_table_system_call+8)
 814         la      %r12,__LC_RETURN_PSW
 815         br      %r14
 816 cleanup_system_call_insn:
 817         .quad   sysc_saveall
 818 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
 819         .quad   system_call
 820         .quad   sysc_vtime
 821         .quad   sysc_stime
 822         .quad   sysc_update
 823 #endif
 824
 825 cleanup_sysc_return:
 826         mvc     __LC_RETURN_PSW(8),0(%r12)
 827         mvc     __LC_RETURN_PSW+8(8),BASED(cleanup_table_sysc_return)
 828         la      %r12,__LC_RETURN_PSW
 829         br      %r14
 830
 831 cleanup_sysc_leave:
 832         clc     8(8,%r12),BASED(cleanup_sysc_leave_insn)
 833         je      0f
 834 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
 835         mvc     __LC_EXIT_TIMER(8),__LC_ASYNC_ENTER_TIMER
 836         clc     8(8,%r12),BASED(cleanup_sysc_leave_insn+8)
 837         je      0f
 838 #endif
 839         mvc     __LC_RETURN_PSW(16),SP_PSW(%r15)
 840         mvc     __LC_SAVE_AREA+32(32),SP_R12(%r15)
 841         lmg     %r0,%r11,SP_R0(%r15)
 842         lg      %r15,SP_R15(%r15)
 843 0:      la      %r12,__LC_RETURN_PSW
 844         br      %r14
 845 cleanup_sysc_leave_insn:
 846 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
 847         .quad   sysc_leave + 16
 848 #endif
 849         .quad   sysc_leave + 12
 850
 851 /*
 852  * Integer constants
 853  */
 854                .align 4
 855 .Lconst:
 856 .Lc_pactive:   .long  PREEMPT_ACTIVE
 857 .Lnr_syscalls: .long  NR_syscalls
 858 .L0x0130:      .short 0x130
 859 .L0x0140:      .short 0x140
 860 .L0x0150:      .short 0x150
 861 .L0x0160:      .short 0x160
 862 .L0x0170:      .short 0x170
 863 .Lcritical_start:
 864                .quad  __critical_start
 865 .Lcritical_end:
 866                .quad  __critical_end
 867
 868 #define SYSCALL(esa,esame,emu)  .long esame
 869         .globl  sys_call_table
 870 sys_call_table:
 871 #include "syscalls.S"
 872 #undef SYSCALL
 873
 874 #ifdef CONFIG_S390_SUPPORT
 875
 876 #define SYSCALL(esa,esame,emu)  .long emu
 877         .globl  sys_call_table_emu
 878 sys_call_table_emu:
 879 #include "syscalls.S"
 880 #undef SYSCALL
 881 #endif