arch/s390/kernel/entry.S

   1 /*
   2  *  arch/s390/kernel/entry.S
   3  *    S390 low-level entry points.
   4  *
   5  *    Copyright (C) IBM Corp. 1999,2012
   6  *    Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
   7  *               Hartmut Penner (hp@de.ibm.com),
   8  *               Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com),
   9  *               Heiko Carstens <heiko.carstens@de.ibm.com>
  10  */
  11
  12 #include <linux/init.h>
  13 #include <linux/linkage.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
  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
  46 STACK_SHIFT = PAGE_SHIFT + THREAD_ORDER
  47 STACK_SIZE  = 1 << STACK_SHIFT
  48
  49 #define BASED(name) name-system_call(%r13)
  50
  51         .macro  TRACE_IRQS_ON
  52 #ifdef CONFIG_TRACE_IRQFLAGS
  53         basr    %r2,%r0
  54         l       %r1,BASED(.Lhardirqs_on)
  55         basr    %r14,%r1                # call trace_hardirqs_on_caller
  56 #endif
  57         .endm
  58
  59         .macro  TRACE_IRQS_OFF
  60 #ifdef CONFIG_TRACE_IRQFLAGS
  61         basr    %r2,%r0
  62         l       %r1,BASED(.Lhardirqs_off)
  63         basr    %r14,%r1                # call 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         l       %r1,BASED(.Llockdep_sys_exit)
  72         basr    %r14,%r1                # call lockdep_sys_exit
  73 #endif
  74         .endm
  75
  76         .macro  CHECK_STACK stacksize,savearea
  77 #ifdef CONFIG_CHECK_STACK
  78         tml     %r15,\stacksize - CONFIG_STACK_GUARD
  79         la      %r14,\savearea
  80         jz      stack_overflow
  81 #endif
  82         .endm
  83
  84         .macro  SWITCH_ASYNC savearea,stack,shift
  85         tmh     %r8,0x0001              # interrupting from user ?
  86         jnz     1f
  87         lr      %r14,%r9
  88         sl      %r14,BASED(.Lcritical_start)
  89         cl      %r14,BASED(.Lcritical_length)
  90         jhe     0f
  91         la      %r11,\savearea          # inside critical section, do cleanup
  92         bras    %r14,cleanup_critical
  93         tmh     %r8,0x0001              # retest problem state after cleanup
  94         jnz     1f
  95 0:      l       %r14,\stack             # are we already on the target stack?
  96         slr     %r14,%r15
  97         sra     %r14,\shift
  98         jnz     1f
  99         CHECK_STACK 1<<\shift,\savearea
 100         j       2f
 101 1:      l       %r15,\stack             # load target stack
 102 2:      ahi     %r15,-(STACK_FRAME_OVERHEAD + __PT_SIZE)
 103         la      %r11,STACK_FRAME_OVERHEAD(%r15)
 104         .endm
 105
 106         .macro  ADD64 high,low,timer
 107         al      \high,\timer
 108         al      \low,4+\timer
 109         brc     12,.+8
 110         ahi     \high,1
 111         .endm
 112
 113         .macro  SUB64 high,low,timer
 114         sl      \high,\timer
 115         sl      \low,4+\timer
 116         brc     3,.+8
 117         ahi     \high,-1
 118         .endm
 119
 120         .macro  UPDATE_VTIME high,low,enter_timer
 121         lm      \high,\low,__LC_EXIT_TIMER
 122         SUB64   \high,\low,\enter_timer
 123         ADD64   \high,\low,__LC_USER_TIMER
 124         stm     \high,\low,__LC_USER_TIMER
 125         lm      \high,\low,__LC_LAST_UPDATE_TIMER
 126         SUB64   \high,\low,__LC_EXIT_TIMER
 127         ADD64   \high,\low,__LC_SYSTEM_TIMER
 128         stm     \high,\low,__LC_SYSTEM_TIMER
 129         mvc     __LC_LAST_UPDATE_TIMER(8),\enter_timer
 130         .endm
 131
 132         .macro REENABLE_IRQS
 133         st      %r8,__LC_RETURN_PSW
 134         ni      __LC_RETURN_PSW,0xbf
 135         ssm     __LC_RETURN_PSW
 136         .endm
 137
 138         .section .kprobes.text, "ax"
 139
 140 /*
 141  * Scheduler resume function, called by switch_to
 142  *  gpr2 = (task_struct *) prev
 143  *  gpr3 = (task_struct *) next
 144  * Returns:
 145  *  gpr2 = prev
 146  */
 147 ENTRY(__switch_to)
 148         stm     %r6,%r15,__SF_GPRS(%r15)        # store gprs of prev task
 149         st      %r15,__THREAD_ksp(%r2)          # store kernel stack of prev
 150         l       %r4,__THREAD_info(%r2)          # get thread_info of prev
 151         l       %r5,__THREAD_info(%r3)          # get thread_info of next
 152         lr      %r15,%r5
 153         ahi     %r15,STACK_SIZE                 # end of kernel stack of next
 154         st      %r3,__LC_CURRENT                # store task struct of next
 155         st      %r5,__LC_THREAD_INFO            # store thread info of next
 156         st      %r15,__LC_KERNEL_STACK          # store end of kernel stack
 157         lctl    %c4,%c4,__TASK_pid(%r3)         # load pid to control reg. 4
 158         mvc     __LC_CURRENT_PID(4,%r0),__TASK_pid(%r3) # store pid of next
 159         l       %r15,__THREAD_ksp(%r3)          # load kernel stack of next
 160         tm      __TI_flags+3(%r4),_TIF_MCCK_PENDING # machine check pending?
 161         jz      0f
 162         ni      __TI_flags+3(%r4),255-_TIF_MCCK_PENDING # clear flag in prev
 163         oi      __TI_flags+3(%r5),_TIF_MCCK_PENDING     # set it in next
 164 0:      lm      %r6,%r15,__SF_GPRS(%r15)        # load gprs of next task
 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 ENTRY(system_call)
 174         stpt    __LC_SYNC_ENTER_TIMER
 175 sysc_stm:
 176         stm     %r8,%r15,__LC_SAVE_AREA_SYNC
 177         l       %r12,__LC_THREAD_INFO
 178         l       %r13,__LC_SVC_NEW_PSW+4
 179 sysc_per:
 180         l       %r15,__LC_KERNEL_STACK
 181         ahi     %r15,-(STACK_FRAME_OVERHEAD + __PT_SIZE)
 182         la      %r11,STACK_FRAME_OVERHEAD(%r15) # pointer to pt_regs
 183 sysc_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
 189 sysc_do_svc:
 190         oi      __TI_flags+3(%r12),_TIF_SYSCALL
 191         lh      %r8,__PT_INT_CODE+2(%r11)
 192         sla     %r8,2                           # shift and test for svc0
 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         sth     %r1,__PT_INT_CODE+2(%r11)
 198         lr      %r8,%r1
 199         sla     %r8,2
 200 sysc_nr_ok:
 201         l       %r10,BASED(.Lsys_call_table)    # 31 bit system call table
 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
 211 sysc_return:
 212         LOCKDEP_SYS_EXIT
 213 sysc_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
 219 sysc_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
 224 sysc_done:
 225
 226 #
 227 # One of the work bits is on. Find out which one.
 228 #
 229 sysc_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_SIGPENDING
 235         jo      sysc_sigpending
 236         tm      __TI_flags+3(%r12),_TIF_NOTIFY_RESUME
 237         jo      sysc_notify_resume
 238         tm      __TI_flags+3(%r12),_TIF_PER_TRAP
 239         jo      sysc_singlestep
 240         j       sysc_return             # beware of critical section cleanup
 241
 242 #
 243 # _TIF_NEED_RESCHED is set, call schedule
 244 #
 245 sysc_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 #
 253 sysc_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 #
 261 sysc_sigpending:
 262         ni      __TI_flags+3(%r12),255-_TIF_PER_TRAP # clear TIF_PER_TRAP
 263         lr      %r2,%r11                # pass pointer to pt_regs
 264         l       %r1,BASED(.Ldo_signal)
 265         basr    %r14,%r1                # call do_signal
 266         tm      __TI_flags+3(%r12),_TIF_SYSCALL
 267         jno     sysc_return
 268         lm      %r2,%r7,__PT_R2(%r11)   # load svc arguments
 269         xr      %r8,%r8                 # svc 0 returns -ENOSYS
 270         clc     __PT_INT_CODE+2(2,%r11),BASED(.Lnr_syscalls+2)
 271         jnl     sysc_nr_ok              # invalid svc number -> do svc 0
 272         lh      %r8,__PT_INT_CODE+2(%r11)       # load new svc number
 273         sla     %r8,2
 274         j       sysc_nr_ok              # restart svc
 275
 276 #
 277 # _TIF_NOTIFY_RESUME is set, call do_notify_resume
 278 #
 279 sysc_notify_resume:
 280         lr      %r2,%r11                # pass pointer to pt_regs
 281         l       %r1,BASED(.Ldo_notify_resume)
 282         la      %r14,BASED(sysc_return)
 283         br      %r1                     # call do_notify_resume
 284
 285 #
 286 # _TIF_PER_TRAP is set, call do_per_trap
 287 #
 288 sysc_singlestep:
 289         ni      __TI_flags+3(%r12),255-(_TIF_SYSCALL | _TIF_PER_TRAP)
 290         lr      %r2,%r11                # pass pointer to pt_regs
 291         l       %r1,BASED(.Ldo_per_trap)
 292         la      %r14,BASED(sysc_return)
 293         br      %r1                     # call do_per_trap
 294
 295 #
 296 # call tracehook_report_syscall_entry/tracehook_report_syscall_exit before
 297 # and after the system call
 298 #
 299 sysc_tracesys:
 300         l       %r1,BASED(.Ltrace_enter)
 301         lr      %r2,%r11                # pass pointer to pt_regs
 302         la      %r3,0
 303         xr      %r0,%r0
 304         icm     %r0,3,__PT_INT_CODE+2(%r11)
 305         st      %r0,__PT_R2(%r11)
 306         basr    %r14,%r1                # call do_syscall_trace_enter
 307         cl      %r2,BASED(.Lnr_syscalls)
 308         jnl     sysc_tracenogo
 309         lr      %r8,%r2
 310         sll     %r8,2
 311         l       %r9,0(%r8,%r10)
 312 sysc_tracego:
 313         lm      %r3,%r7,__PT_R3(%r11)
 314         st      %r7,STACK_FRAME_OVERHEAD(%r15)
 315         l       %r2,__PT_ORIG_GPR2(%r11)
 316         basr    %r14,%r9                # call sys_xxx
 317         st      %r2,__PT_R2(%r11)       # store return value
 318 sysc_tracenogo:
 319         tm      __TI_flags+2(%r12),_TIF_TRACE >> 8
 320         jz      sysc_return
 321         l       %r1,BASED(.Ltrace_exit)
 322         lr      %r2,%r11                # pass pointer to pt_regs
 323         la      %r14,BASED(sysc_return)
 324         br      %r1                     # call do_syscall_trace_exit
 325
 326 #
 327 # a new process exits the kernel with ret_from_fork
 328 #
 329 ENTRY(ret_from_fork)
 330         la      %r11,STACK_FRAME_OVERHEAD(%r15)
 331         l       %r12,__LC_THREAD_INFO
 332         l       %r13,__LC_SVC_NEW_PSW+4
 333         tm      __PT_PSW+1(%r11),0x01   # forking a kernel thread ?
 334         jo      0f
 335         st      %r15,__PT_R15(%r11)     # store stack pointer for new kthread
 336 0:      l       %r1,BASED(.Lschedule_tail)
 337         basr    %r14,%r1                # call schedule_tail
 338         TRACE_IRQS_ON
 339         ssm     __LC_SVC_NEW_PSW        # reenable interrupts
 340         j       sysc_tracenogo
 341
 342 #
 343 # kernel_execve function needs to deal with pt_regs that is not
 344 # at the usual place
 345 #
 346 ENTRY(kernel_execve)
 347         stm     %r12,%r15,48(%r15)
 348         lr      %r14,%r15
 349         l       %r13,__LC_SVC_NEW_PSW+4
 350         ahi     %r15,-(STACK_FRAME_OVERHEAD + __PT_SIZE)
 351         st      %r14,__SF_BACKCHAIN(%r15)
 352         la      %r12,STACK_FRAME_OVERHEAD(%r15)
 353         xc      0(__PT_SIZE,%r12),0(%r12)
 354         l       %r1,BASED(.Ldo_execve)
 355         lr      %r5,%r12
 356         basr    %r14,%r1                # call do_execve
 357         ltr     %r2,%r2
 358         je      0f
 359         ahi     %r15,(STACK_FRAME_OVERHEAD + __PT_SIZE)
 360         lm      %r12,%r15,48(%r15)
 361         br      %r14
 362         # execve succeeded.
 363 0:      ssm     __LC_PGM_NEW_PSW        # disable I/O and ext. interrupts
 364         l       %r15,__LC_KERNEL_STACK  # load ksp
 365         ahi     %r15,-(STACK_FRAME_OVERHEAD + __PT_SIZE)
 366         la      %r11,STACK_FRAME_OVERHEAD(%r15)
 367         mvc     0(__PT_SIZE,%r11),0(%r12)       # copy pt_regs
 368         l       %r12,__LC_THREAD_INFO
 369         xc      __SF_BACKCHAIN(4,%r15),__SF_BACKCHAIN(%r15)
 370         ssm     __LC_SVC_NEW_PSW        # reenable interrupts
 371         l       %r1,BASED(.Lexecve_tail)
 372         basr    %r14,%r1                # call execve_tail
 373         j       sysc_return
 374
 375 /*
 376  * Program check handler routine
 377  */
 378
 379 ENTRY(pgm_check_handler)
 380         stpt    __LC_SYNC_ENTER_TIMER
 381         stm     %r8,%r15,__LC_SAVE_AREA_SYNC
 382         l       %r12,__LC_THREAD_INFO
 383         l       %r13,__LC_SVC_NEW_PSW+4
 384         lm      %r8,%r9,__LC_PGM_OLD_PSW
 385         tmh     %r8,0x0001              # test problem state bit
 386         jnz     1f                      # -> fault in user space
 387         tmh     %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,%r15,__LC_SYNC_ENTER_TIMER
 394         l       %r15,__LC_KERNEL_STACK
 395 2:      ahi     %r15,-(STACK_FRAME_OVERHEAD + __PT_SIZE)
 396         la      %r11,STACK_FRAME_OVERHEAD(%r15)
 397         stm     %r0,%r7,__PT_R0(%r11)
 398         mvc     __PT_R8(32,%r11),__LC_SAVE_AREA_SYNC
 399         stm     %r8,%r9,__PT_PSW(%r11)
 400         mvc     __PT_INT_CODE(4,%r11),__LC_PGM_ILC
 401         mvc     __PT_INT_PARM_LONG(4,%r11),__LC_TRANS_EXC_CODE
 402         tm      __LC_PGM_ILC+3,0x80     # check for per exception
 403         jz      0f
 404         l       %r1,__TI_task(%r12)
 405         tmh     %r8,0x0001              # kernel per event ?
 406         jz      pgm_kprobe
 407         oi      __TI_flags+3(%r12),_TIF_PER_TRAP
 408         mvc     __THREAD_per_address(4,%r1),__LC_PER_ADDRESS
 409         mvc     __THREAD_per_cause(2,%r1),__LC_PER_CAUSE
 410         mvc     __THREAD_per_paid(1,%r1),__LC_PER_PAID
 411 0:      REENABLE_IRQS
 412         xc      __SF_BACKCHAIN(4,%r15),__SF_BACKCHAIN(%r15)
 413         l       %r1,BASED(.Ljump_table)
 414         la      %r10,0x7f
 415         n       %r10,__PT_INT_CODE(%r11)
 416         je      sysc_return
 417         sll     %r10,2
 418         l       %r1,0(%r10,%r1)         # load address of handler routine
 419         lr      %r2,%r11                # pass pointer to pt_regs
 420         basr    %r14,%r1                # branch to interrupt-handler
 421         j       sysc_return
 422
 423 #
 424 # PER event in supervisor state, must be kprobes
 425 #
 426 pgm_kprobe:
 427         REENABLE_IRQS
 428         xc      __SF_BACKCHAIN(4,%r15),__SF_BACKCHAIN(%r15)
 429         l       %r1,BASED(.Ldo_per_trap)
 430         lr      %r2,%r11                # pass pointer to pt_regs
 431         basr    %r14,%r1                # call do_per_trap
 432         j       sysc_return
 433
 434 #
 435 # single stepped system call
 436 #
 437 pgm_svcper:
 438         oi      __TI_flags+3(%r12),_TIF_PER_TRAP
 439         mvc     __LC_RETURN_PSW(4),__LC_SVC_NEW_PSW
 440         mvc     __LC_RETURN_PSW+4(4),BASED(.Lsysc_per)
 441         lpsw    __LC_RETURN_PSW         # branch to sysc_per and enable irqs
 442
 443 /*
 444  * IO interrupt handler routine
 445  */
 446
 447 ENTRY(io_int_handler)
 448         stck    __LC_INT_CLOCK
 449         stpt    __LC_ASYNC_ENTER_TIMER
 450         stm     %r8,%r15,__LC_SAVE_AREA_ASYNC
 451         l       %r12,__LC_THREAD_INFO
 452         l       %r13,__LC_SVC_NEW_PSW+4
 453         lm      %r8,%r9,__LC_IO_OLD_PSW
 454         tmh     %r8,0x0001              # interrupting from user ?
 455         jz      io_skip
 456         UPDATE_VTIME %r14,%r15,__LC_ASYNC_ENTER_TIMER
 457 io_skip:
 458         SWITCH_ASYNC __LC_SAVE_AREA_ASYNC,__LC_ASYNC_STACK,STACK_SHIFT
 459         stm     %r0,%r7,__PT_R0(%r11)
 460         mvc     __PT_R8(32,%r11),__LC_SAVE_AREA_ASYNC
 461         stm     %r8,%r9,__PT_PSW(%r11)
 462         TRACE_IRQS_OFF
 463         xc      __SF_BACKCHAIN(4,%r15),__SF_BACKCHAIN(%r15)
 464         l       %r1,BASED(.Ldo_IRQ)
 465         lr      %r2,%r11                # pass pointer to pt_regs
 466         basr    %r14,%r1                # call do_IRQ
 467 io_return:
 468         LOCKDEP_SYS_EXIT
 469         TRACE_IRQS_ON
 470 io_tif:
 471         tm      __TI_flags+3(%r12),_TIF_WORK_INT
 472         jnz     io_work                 # there is work to do (signals etc.)
 473 io_restore:
 474         mvc     __LC_RETURN_PSW(8),__PT_PSW(%r11)
 475         stpt    __LC_EXIT_TIMER
 476         lm      %r0,%r15,__PT_R0(%r11)
 477         lpsw    __LC_RETURN_PSW
 478 io_done:
 479
 480 #
 481 # There is work todo, find out in which context we have been interrupted:
 482 # 1) if we return to user space we can do all _TIF_WORK_INT work
 483 # 2) if we return to kernel code and preemptive scheduling is enabled check
 484 #    the preemption counter and if it is zero call preempt_schedule_irq
 485 # Before any work can be done, a switch to the kernel stack is required.
 486 #
 487 io_work:
 488         tm      __PT_PSW+1(%r11),0x01   # returning to user ?
 489         jo      io_work_user            # yes -> do resched & signal
 490 #ifdef CONFIG_PREEMPT
 491         # check for preemptive scheduling
 492         icm     %r0,15,__TI_precount(%r12)
 493         jnz     io_restore              # preemption disabled
 494         tm      __TI_flags+3(%r12),_TIF_NEED_RESCHED
 495         jno     io_restore
 496         # switch to kernel stack
 497         l       %r1,__PT_R15(%r11)
 498         ahi     %r1,-(STACK_FRAME_OVERHEAD + __PT_SIZE)
 499         mvc     STACK_FRAME_OVERHEAD(__PT_SIZE,%r1),0(%r11)
 500         xc      __SF_BACKCHAIN(4,%r1),__SF_BACKCHAIN(%r1)
 501         la      %r11,STACK_FRAME_OVERHEAD(%r1)
 502         lr      %r15,%r1
 503         # TRACE_IRQS_ON already done at io_return, call
 504         # TRACE_IRQS_OFF to keep things symmetrical
 505         TRACE_IRQS_OFF
 506         l       %r1,BASED(.Lpreempt_irq)
 507         basr    %r14,%r1                # call preempt_schedule_irq
 508         j       io_return
 509 #else
 510         j       io_restore
 511 #endif
 512
 513 #
 514 # Need to do work before returning to userspace, switch to kernel stack
 515 #
 516 io_work_user:
 517         l       %r1,__LC_KERNEL_STACK
 518         ahi     %r1,-(STACK_FRAME_OVERHEAD + __PT_SIZE)
 519         mvc     STACK_FRAME_OVERHEAD(__PT_SIZE,%r1),0(%r11)
 520         xc      __SF_BACKCHAIN(4,%r1),__SF_BACKCHAIN(%r1)
 521         la      %r11,STACK_FRAME_OVERHEAD(%r1)
 522         lr      %r15,%r1
 523
 524 #
 525 # One of the work bits is on. Find out which one.
 526 # Checked are: _TIF_SIGPENDING, _TIF_NOTIFY_RESUME, _TIF_NEED_RESCHED
 527 #               and _TIF_MCCK_PENDING
 528 #
 529 io_work_tif:
 530         tm      __TI_flags+3(%r12),_TIF_MCCK_PENDING
 531         jo      io_mcck_pending
 532         tm      __TI_flags+3(%r12),_TIF_NEED_RESCHED
 533         jo      io_reschedule
 534         tm      __TI_flags+3(%r12),_TIF_SIGPENDING
 535         jo      io_sigpending
 536         tm      __TI_flags+3(%r12),_TIF_NOTIFY_RESUME
 537         jo      io_notify_resume
 538         j       io_return               # beware of critical section cleanup
 539
 540 #
 541 # _TIF_MCCK_PENDING is set, call handler
 542 #
 543 io_mcck_pending:
 544         # TRACE_IRQS_ON already done at io_return
 545         l       %r1,BASED(.Lhandle_mcck)
 546         basr    %r14,%r1                # TIF bit will be cleared by handler
 547         TRACE_IRQS_OFF
 548         j       io_return
 549
 550 #
 551 # _TIF_NEED_RESCHED is set, call schedule
 552 #
 553 io_reschedule:
 554         # TRACE_IRQS_ON already done at io_return
 555         l       %r1,BASED(.Lschedule)
 556         ssm     __LC_SVC_NEW_PSW        # reenable interrupts
 557         basr    %r14,%r1                # call scheduler
 558         ssm     __LC_PGM_NEW_PSW        # disable I/O and ext. interrupts
 559         TRACE_IRQS_OFF
 560         j       io_return
 561
 562 #
 563 # _TIF_SIGPENDING is set, call do_signal
 564 #
 565 io_sigpending:
 566         # TRACE_IRQS_ON already done at io_return
 567         l       %r1,BASED(.Ldo_signal)
 568         ssm     __LC_SVC_NEW_PSW        # reenable interrupts
 569         lr      %r2,%r11                # pass pointer to pt_regs
 570         basr    %r14,%r1                # call do_signal
 571         ssm     __LC_PGM_NEW_PSW        # disable I/O and ext. interrupts
 572         TRACE_IRQS_OFF
 573         j       io_return
 574
 575 #
 576 # _TIF_SIGPENDING is set, call do_signal
 577 #
 578 io_notify_resume:
 579         # TRACE_IRQS_ON already done at io_return
 580         l       %r1,BASED(.Ldo_notify_resume)
 581         ssm     __LC_SVC_NEW_PSW        # reenable interrupts
 582         lr      %r2,%r11                # pass pointer to pt_regs
 583         basr    %r14,%r1                # call do_notify_resume
 584         ssm     __LC_PGM_NEW_PSW        # disable I/O and ext. interrupts
 585         TRACE_IRQS_OFF
 586         j       io_return
 587
 588 /*
 589  * External interrupt handler routine
 590  */
 591
 592 ENTRY(ext_int_handler)
 593         stck    __LC_INT_CLOCK
 594         stpt    __LC_ASYNC_ENTER_TIMER
 595         stm     %r8,%r15,__LC_SAVE_AREA_ASYNC
 596         l       %r12,__LC_THREAD_INFO
 597         l       %r13,__LC_SVC_NEW_PSW+4
 598         lm      %r8,%r9,__LC_EXT_OLD_PSW
 599         tmh     %r8,0x0001              # interrupting from user ?
 600         jz      ext_skip
 601         UPDATE_VTIME %r14,%r15,__LC_ASYNC_ENTER_TIMER
 602 ext_skip:
 603         SWITCH_ASYNC __LC_SAVE_AREA_ASYNC,__LC_ASYNC_STACK,STACK_SHIFT
 604         stm     %r0,%r7,__PT_R0(%r11)
 605         mvc     __PT_R8(32,%r11),__LC_SAVE_AREA_ASYNC
 606         stm     %r8,%r9,__PT_PSW(%r11)
 607         TRACE_IRQS_OFF
 608         lr      %r2,%r11                # pass pointer to pt_regs
 609         l       %r3,__LC_EXT_CPU_ADDR   # get cpu address + interruption code
 610         l       %r4,__LC_EXT_PARAMS     # get external parameters
 611         l       %r1,BASED(.Ldo_extint)
 612         basr    %r14,%r1                # call do_extint
 613         j       io_return
 614
 615 /*
 616  * Load idle PSW. The second "half" of this function is in cleanup_idle.
 617  */
 618 ENTRY(psw_idle)
 619         st      %r4,__SF_EMPTY(%r15)
 620         basr    %r1,0
 621         la      %r1,psw_idle_lpsw+4-.(%r1)
 622         st      %r1,__SF_EMPTY+4(%r15)
 623         oi      __SF_EMPTY+4(%r15),0x80
 624         la      %r1,.Lvtimer_max-psw_idle_lpsw-4(%r1)
 625         stck    __IDLE_ENTER(%r2)
 626         ltr     %r5,%r5
 627         stpt    __VQ_IDLE_ENTER(%r3)
 628         jz      psw_idle_lpsw
 629         spt     0(%r1)
 630 psw_idle_lpsw:
 631         lpsw    __SF_EMPTY(%r15)
 632         br      %r14
 633 psw_idle_end:
 634
 635 __critical_end:
 636
 637 /*
 638  * Machine check handler routines
 639  */
 640
 641 ENTRY(mcck_int_handler)
 642         stck    __LC_MCCK_CLOCK
 643         spt     __LC_CPU_TIMER_SAVE_AREA        # revalidate cpu timer
 644         lm      %r0,%r15,__LC_GPREGS_SAVE_AREA  # revalidate gprs
 645         l       %r12,__LC_THREAD_INFO
 646         l       %r13,__LC_SVC_NEW_PSW+4
 647         lm      %r8,%r9,__LC_MCK_OLD_PSW
 648         tm      __LC_MCCK_CODE,0x80     # system damage?
 649         jo      mcck_panic              # yes -> rest of mcck code invalid
 650         la      %r14,__LC_CPU_TIMER_SAVE_AREA
 651         mvc     __LC_MCCK_ENTER_TIMER(8),0(%r14)
 652         tm      __LC_MCCK_CODE+5,0x02   # stored cpu timer value valid?
 653         jo      3f
 654         la      %r14,__LC_SYNC_ENTER_TIMER
 655         clc     0(8,%r14),__LC_ASYNC_ENTER_TIMER
 656         jl      0f
 657         la      %r14,__LC_ASYNC_ENTER_TIMER
 658 0:      clc     0(8,%r14),__LC_EXIT_TIMER
 659         jl      1f
 660         la      %r14,__LC_EXIT_TIMER
 661 1:      clc     0(8,%r14),__LC_LAST_UPDATE_TIMER
 662         jl      2f
 663         la      %r14,__LC_LAST_UPDATE_TIMER
 664 2:      spt     0(%r14)
 665         mvc     __LC_MCCK_ENTER_TIMER(8),0(%r14)
 666 3:      tm      __LC_MCCK_CODE+2,0x09   # mwp + ia of old psw valid?
 667         jno     mcck_panic              # no -> skip cleanup critical
 668         tm      %r8,0x0001              # interrupting from user ?
 669         jz      mcck_skip
 670         UPDATE_VTIME %r14,%r15,__LC_MCCK_ENTER_TIMER
 671 mcck_skip:
 672         SWITCH_ASYNC __LC_GPREGS_SAVE_AREA+32,__LC_PANIC_STACK,PAGE_SHIFT
 673         mvc     __PT_R0(64,%r11),__LC_GPREGS_SAVE_AREA
 674         stm     %r8,%r9,__PT_PSW(%r11)
 675         xc      __SF_BACKCHAIN(4,%r15),__SF_BACKCHAIN(%r15)
 676         l       %r1,BASED(.Ldo_machine_check)
 677         lr      %r2,%r11                # pass pointer to pt_regs
 678         basr    %r14,%r1                # call s390_do_machine_check
 679         tm      __PT_PSW+1(%r11),0x01   # returning to user ?
 680         jno     mcck_return
 681         l       %r1,__LC_KERNEL_STACK   # switch to kernel stack
 682         ahi     %r1,-(STACK_FRAME_OVERHEAD + __PT_SIZE)
 683         mvc     STACK_FRAME_OVERHEAD(__PT_SIZE,%r1),0(%r11)
 684         xc      __SF_BACKCHAIN(4,%r1),__SF_BACKCHAIN(%r1)
 685         la      %r11,STACK_FRAME_OVERHEAD(%r15)
 686         lr      %r15,%r1
 687         ssm     __LC_PGM_NEW_PSW        # turn dat on, keep irqs off
 688         tm      __TI_flags+3(%r12),_TIF_MCCK_PENDING
 689         jno     mcck_return
 690         TRACE_IRQS_OFF
 691         l       %r1,BASED(.Lhandle_mcck)
 692         basr    %r14,%r1                # call s390_handle_mcck
 693         TRACE_IRQS_ON
 694 mcck_return:
 695         mvc     __LC_RETURN_MCCK_PSW(8),__PT_PSW(%r11) # move return PSW
 696         tm      __LC_RETURN_MCCK_PSW+1,0x01 # returning to user ?
 697         jno     0f
 698         lm      %r0,%r15,__PT_R0(%r11)
 699         stpt    __LC_EXIT_TIMER
 700         lpsw    __LC_RETURN_MCCK_PSW
 701 0:      lm      %r0,%r15,__PT_R0(%r11)
 702         lpsw    __LC_RETURN_MCCK_PSW
 703
 704 mcck_panic:
 705         l       %r14,__LC_PANIC_STACK
 706         slr     %r14,%r15
 707         sra     %r14,PAGE_SHIFT
 708         jz      0f
 709         l       %r15,__LC_PANIC_STACK
 710 0:      ahi     %r15,-(STACK_FRAME_OVERHEAD + __PT_SIZE)
 711         j       mcck_skip
 712
 713 #
 714 # PSW restart interrupt handler
 715 #
 716 ENTRY(restart_int_handler)
 717         st      %r15,__LC_SAVE_AREA_RESTART
 718         l       %r15,__LC_RESTART_STACK
 719         ahi     %r15,-__PT_SIZE                 # create pt_regs on stack
 720         xc      0(__PT_SIZE,%r15),0(%r15)
 721         stm     %r0,%r14,__PT_R0(%r15)
 722         mvc     __PT_R15(4,%r15),__LC_SAVE_AREA_RESTART
 723         mvc     __PT_PSW(8,%r15),__LC_RST_OLD_PSW # store restart old psw
 724         ahi     %r15,-STACK_FRAME_OVERHEAD      # create stack frame on stack
 725         xc      0(STACK_FRAME_OVERHEAD,%r15),0(%r15)
 726         lm      %r1,%r3,__LC_RESTART_FN         # load fn, parm & source cpu
 727         ltr     %r3,%r3                         # test source cpu address
 728         jm      1f                              # negative -> skip source stop
 729 0:      sigp    %r4,%r3,1                       # sigp sense to source cpu
 730         brc     10,0b                           # wait for status stored
 731 1:      basr    %r14,%r1                        # call function
 732         stap    __SF_EMPTY(%r15)                # store cpu address
 733         lh      %r3,__SF_EMPTY(%r15)
 734 2:      sigp    %r4,%r3,5                       # sigp stop to current cpu
 735         brc     2,2b
 736 3:      j       3b
 737
 738         .section .kprobes.text, "ax"
 739
 740 #ifdef CONFIG_CHECK_STACK
 741 /*
 742  * The synchronous or the asynchronous stack overflowed. We are dead.
 743  * No need to properly save the registers, we are going to panic anyway.
 744  * Setup a pt_regs so that show_trace can provide a good call trace.
 745  */
 746 stack_overflow:
 747         l       %r15,__LC_PANIC_STACK   # change to panic stack
 748         ahi     %r15,-__PT_SIZE         # create pt_regs
 749         stm     %r0,%r7,__PT_R0(%r15)
 750         stm     %r8,%r9,__PT_PSW(%r15)
 751         mvc     __PT_R8(32,%r11),0(%r14)
 752         lr      %r15,%r11
 753         ahi     %r15,-STACK_FRAME_OVERHEAD
 754         l       %r1,BASED(1f)
 755         xc      __SF_BACKCHAIN(4,%r15),__SF_BACKCHAIN(%r15)
 756         lr      %r2,%r11                # pass pointer to pt_regs
 757         br      %r1                     # branch to kernel_stack_overflow
 758 1:      .long   kernel_stack_overflow
 759 #endif
 760
 761 cleanup_table:
 762         .long   system_call + 0x80000000
 763         .long   sysc_do_svc + 0x80000000
 764         .long   sysc_tif + 0x80000000
 765         .long   sysc_restore + 0x80000000
 766         .long   sysc_done + 0x80000000
 767         .long   io_tif + 0x80000000
 768         .long   io_restore + 0x80000000
 769         .long   io_done + 0x80000000
 770         .long   psw_idle + 0x80000000
 771         .long   psw_idle_end + 0x80000000
 772
 773 cleanup_critical:
 774         cl      %r9,BASED(cleanup_table)        # system_call
 775         jl      0f
 776         cl      %r9,BASED(cleanup_table+4)      # sysc_do_svc
 777         jl      cleanup_system_call
 778         cl      %r9,BASED(cleanup_table+8)      # sysc_tif
 779         jl      0f
 780         cl      %r9,BASED(cleanup_table+12)     # sysc_restore
 781         jl      cleanup_sysc_tif
 782         cl      %r9,BASED(cleanup_table+16)     # sysc_done
 783         jl      cleanup_sysc_restore
 784         cl      %r9,BASED(cleanup_table+20)     # io_tif
 785         jl      0f
 786         cl      %r9,BASED(cleanup_table+24)     # io_restore
 787         jl      cleanup_io_tif
 788         cl      %r9,BASED(cleanup_table+28)     # io_done
 789         jl      cleanup_io_restore
 790         cl      %r9,BASED(cleanup_table+32)     # psw_idle
 791         jl      0f
 792         cl      %r9,BASED(cleanup_table+36)     # psw_idle_end
 793         jl      cleanup_idle
 794 0:      br      %r14
 795
 796 cleanup_system_call:
 797         # check if stpt has been executed
 798         cl      %r9,BASED(cleanup_system_call_insn)
 799         jh      0f
 800         mvc     __LC_SYNC_ENTER_TIMER(8),__LC_ASYNC_ENTER_TIMER
 801         chi     %r11,__LC_SAVE_AREA_ASYNC
 802         je      0f
 803         mvc     __LC_SYNC_ENTER_TIMER(8),__LC_MCCK_ENTER_TIMER
 804 0:      # check if stm has been executed
 805         cl      %r9,BASED(cleanup_system_call_insn+4)
 806         jh      0f
 807         mvc     __LC_SAVE_AREA_SYNC(32),0(%r11)
 808 0:      # set up saved registers r12, and r13
 809         st      %r12,16(%r11)           # r12 thread-info pointer
 810         st      %r13,20(%r11)           # r13 literal-pool pointer
 811         # check if the user time calculation has been done
 812         cl      %r9,BASED(cleanup_system_call_insn+8)
 813         jh      0f
 814         l       %r10,__LC_EXIT_TIMER
 815         l       %r15,__LC_EXIT_TIMER+4
 816         SUB64   %r10,%r15,__LC_SYNC_ENTER_TIMER
 817         ADD64   %r10,%r15,__LC_USER_TIMER
 818         st      %r10,__LC_USER_TIMER
 819         st      %r15,__LC_USER_TIMER+4
 820 0:      # check if the system time calculation has been done
 821         cl      %r9,BASED(cleanup_system_call_insn+12)
 822         jh      0f
 823         l       %r10,__LC_LAST_UPDATE_TIMER
 824         l       %r15,__LC_LAST_UPDATE_TIMER+4
 825         SUB64   %r10,%r15,__LC_EXIT_TIMER
 826         ADD64   %r10,%r15,__LC_SYSTEM_TIMER
 827         st      %r10,__LC_SYSTEM_TIMER
 828         st      %r15,__LC_SYSTEM_TIMER+4
 829 0:      # update accounting time stamp
 830         mvc     __LC_LAST_UPDATE_TIMER(8),__LC_SYNC_ENTER_TIMER
 831         # set up saved register 11
 832         l       %r15,__LC_KERNEL_STACK
 833         ahi     %r15,-__PT_SIZE
 834         st      %r15,12(%r11)           # r11 pt_regs pointer
 835         # fill pt_regs
 836         mvc     __PT_R8(32,%r15),__LC_SAVE_AREA_SYNC
 837         stm     %r0,%r7,__PT_R0(%r15)
 838         mvc     __PT_PSW(8,%r15),__LC_SVC_OLD_PSW
 839         mvc     __PT_INT_CODE(4,%r15),__LC_SVC_ILC
 840         # setup saved register 15
 841         ahi     %r15,-STACK_FRAME_OVERHEAD
 842         st      %r15,28(%r11)           # r15 stack pointer
 843         # set new psw address and exit
 844         l       %r9,BASED(cleanup_table+4)      # sysc_do_svc + 0x80000000
 845         br      %r14
 846 cleanup_system_call_insn:
 847         .long   system_call + 0x80000000
 848         .long   sysc_stm + 0x80000000
 849         .long   sysc_vtime + 0x80000000 + 36
 850         .long   sysc_vtime + 0x80000000 + 76
 851
 852 cleanup_sysc_tif:
 853         l       %r9,BASED(cleanup_table+8)      # sysc_tif + 0x80000000
 854         br      %r14
 855
 856 cleanup_sysc_restore:
 857         cl      %r9,BASED(cleanup_sysc_restore_insn)
 858         jhe     0f
 859         l       %r9,12(%r11)            # get saved pointer to pt_regs
 860         mvc     __LC_RETURN_PSW(8),__PT_PSW(%r9)
 861         mvc     0(32,%r11),__PT_R8(%r9)
 862         lm      %r0,%r7,__PT_R0(%r9)
 863 0:      lm      %r8,%r9,__LC_RETURN_PSW
 864         br      %r14
 865 cleanup_sysc_restore_insn:
 866         .long   sysc_done - 4 + 0x80000000
 867
 868 cleanup_io_tif:
 869         l       %r9,BASED(cleanup_table+20)     # io_tif + 0x80000000
 870         br      %r14
 871
 872 cleanup_io_restore:
 873         cl      %r9,BASED(cleanup_io_restore_insn)
 874         jhe     0f
 875         l       %r9,12(%r11)            # get saved r11 pointer to pt_regs
 876         mvc     __LC_RETURN_PSW(8),__PT_PSW(%r9)
 877         mvc     0(32,%r11),__PT_R8(%r9)
 878         lm      %r0,%r7,__PT_R0(%r9)
 879 0:      lm      %r8,%r9,__LC_RETURN_PSW
 880         br      %r14
 881 cleanup_io_restore_insn:
 882         .long   io_done - 4 + 0x80000000
 883
 884 cleanup_idle:
 885         # copy interrupt clock & cpu timer
 886         mvc     __IDLE_EXIT(8,%r2),__LC_INT_CLOCK
 887         mvc     __VQ_IDLE_EXIT(8,%r3),__LC_ASYNC_ENTER_TIMER
 888         chi     %r11,__LC_SAVE_AREA_ASYNC
 889         je      0f
 890         mvc     __IDLE_EXIT(8,%r2),__LC_MCCK_CLOCK
 891         mvc     __VQ_IDLE_EXIT(8,%r3),__LC_MCCK_ENTER_TIMER
 892 0:      # check if stck has been executed
 893         cl      %r9,BASED(cleanup_idle_insn)
 894         jhe     1f
 895         mvc     __IDLE_ENTER(8,%r2),__IDLE_EXIT(%r2)
 896         mvc     __VQ_IDLE_ENTER(8,%r3),__VQ_IDLE_EXIT(%r3)
 897         j       2f
 898 1:      # check if the cpu timer has been reprogrammed
 899         ltr     %r5,%r5
 900         jz      2f
 901         spt     __VQ_IDLE_ENTER(%r3)
 902 2:      # account system time going idle
 903         lm      %r9,%r10,__LC_STEAL_TIMER
 904         ADD64   %r9,%r10,__IDLE_ENTER(%r2)
 905         SUB64   %r9,%r10,__LC_LAST_UPDATE_CLOCK
 906         stm     %r9,%r10,__LC_STEAL_TIMER
 907         mvc     __LC_LAST_UPDATE_CLOCK(8),__IDLE_EXIT(%r2)
 908         lm      %r9,%r10,__LC_SYSTEM_TIMER
 909         ADD64   %r9,%r10,__LC_LAST_UPDATE_TIMER
 910         SUB64   %r9,%r10,__VQ_IDLE_ENTER(%r3)
 911         stm     %r9,%r10,__LC_SYSTEM_TIMER
 912         mvc     __LC_LAST_UPDATE_TIMER(8),__VQ_IDLE_EXIT(%r3)
 913         # prepare return psw
 914         n       %r8,BASED(cleanup_idle_wait)    # clear wait state bit
 915         l       %r9,24(%r11)                    # return from psw_idle
 916         br      %r14
 917 cleanup_idle_insn:
 918         .long   psw_idle_lpsw + 0x80000000
 919 cleanup_idle_wait:
 920         .long   0xfffdffff
 921
 922 /*
 923  * Integer constants
 924  */
 925         .align  4
 926 .Lnr_syscalls:
 927         .long   NR_syscalls
 928 .Lvtimer_max:
 929         .quad   0x7fffffffffffffff
 930
 931 /*
 932  * Symbol constants
 933  */
 934 .Ldo_machine_check:     .long   s390_do_machine_check
 935 .Lhandle_mcck:          .long   s390_handle_mcck
 936 .Ldo_IRQ:               .long   do_IRQ
 937 .Ldo_extint:            .long   do_extint
 938 .Ldo_signal:            .long   do_signal
 939 .Ldo_notify_resume:     .long   do_notify_resume
 940 .Ldo_per_trap:          .long   do_per_trap
 941 .Ldo_execve:            .long   do_execve
 942 .Lexecve_tail:          .long   execve_tail
 943 .Ljump_table:           .long   pgm_check_table
 944 .Lschedule:             .long   schedule
 945 #ifdef CONFIG_PREEMPT
 946 .Lpreempt_irq:          .long   preempt_schedule_irq
 947 #endif
 948 .Ltrace_enter:          .long   do_syscall_trace_enter
 949 .Ltrace_exit:           .long   do_syscall_trace_exit
 950 .Lschedule_tail:        .long   schedule_tail
 951 .Lsys_call_table:       .long   sys_call_table
 952 .Lsysc_per:             .long   sysc_per + 0x80000000
 953 #ifdef CONFIG_TRACE_IRQFLAGS
 954 .Lhardirqs_on:          .long   trace_hardirqs_on_caller
 955 .Lhardirqs_off:         .long   trace_hardirqs_off_caller
 956 #endif
 957 #ifdef CONFIG_LOCKDEP
 958 .Llockdep_sys_exit:     .long   lockdep_sys_exit
 959 #endif
 960 .Lcritical_start:       .long   __critical_start + 0x80000000
 961 .Lcritical_length:      .long   __critical_end - __critical_start
 962
 963                 .section .rodata, "a"
 964 #define SYSCALL(esa,esame,emu)  .long esa
 965         .globl  sys_call_table
 966 sys_call_table:
 967 #include "syscalls.S"
 968 #undef SYSCALL