arch/s390/kernel/entry.S

   1 /*
   2  *    S390 low-level entry points.
   3  *
   4  *    Copyright IBM Corp. 1999, 2012
   5  *    Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
   6  *               Hartmut Penner (hp@de.ibm.com),
   7  *               Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com),
   8  *               Heiko Carstens <heiko.carstens@de.ibm.com>
   9  */
  10
  11 #include <linux/init.h>
  12 #include <linux/linkage.h>
  13 #include <asm/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 #include <asm/irq.h>
  23 #include <asm/vx-insn.h>
  24 #include <asm/setup.h>
  25 #include <asm/nmi.h>
  26 #include <asm/export.h>
  27
  28 __PT_R0      =  __PT_GPRS
  29 __PT_R1      =  __PT_GPRS + 8
  30 __PT_R2      =  __PT_GPRS + 16
  31 __PT_R3      =  __PT_GPRS + 24
  32 __PT_R4      =  __PT_GPRS + 32
  33 __PT_R5      =  __PT_GPRS + 40
  34 __PT_R6      =  __PT_GPRS + 48
  35 __PT_R7      =  __PT_GPRS + 56
  36 __PT_R8      =  __PT_GPRS + 64
  37 __PT_R9      =  __PT_GPRS + 72
  38 __PT_R10     =  __PT_GPRS + 80
  39 __PT_R11     =  __PT_GPRS + 88
  40 __PT_R12     =  __PT_GPRS + 96
  41 __PT_R13     =  __PT_GPRS + 104
  42 __PT_R14     =  __PT_GPRS + 112
  43 __PT_R15     =  __PT_GPRS + 120
  44
  45 STACK_SHIFT = PAGE_SHIFT + THREAD_SIZE_ORDER
  46 STACK_SIZE  = 1 << STACK_SHIFT
  47 STACK_INIT = STACK_SIZE - STACK_FRAME_OVERHEAD - __PT_SIZE
  48
  49 _TIF_WORK       = (_TIF_SIGPENDING | _TIF_NOTIFY_RESUME | _TIF_NEED_RESCHED | \
  50                    _TIF_UPROBE | _TIF_GUARDED_STORAGE | _TIF_PATCH_PENDING)
  51 _TIF_TRACE      = (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | _TIF_SECCOMP | \
  52                    _TIF_SYSCALL_TRACEPOINT)
  53 _CIF_WORK       = (_CIF_MCCK_PENDING | _CIF_ASCE_PRIMARY | \
  54                    _CIF_ASCE_SECONDARY | _CIF_FPU)
  55 _PIF_WORK       = (_PIF_PER_TRAP)
  56
  57 #define BASED(name) name-cleanup_critical(%r13)
  58
  59         .macro  TRACE_IRQS_ON
  60 #ifdef CONFIG_TRACE_IRQFLAGS
  61         basr    %r2,%r0
  62         brasl   %r14,trace_hardirqs_on_caller
  63 #endif
  64         .endm
  65
  66         .macro  TRACE_IRQS_OFF
  67 #ifdef CONFIG_TRACE_IRQFLAGS
  68         basr    %r2,%r0
  69         brasl   %r14,trace_hardirqs_off_caller
  70 #endif
  71         .endm
  72
  73         .macro  LOCKDEP_SYS_EXIT
  74 #ifdef CONFIG_LOCKDEP
  75         tm      __PT_PSW+1(%r11),0x01   # returning to user ?
  76         jz      .+10
  77         brasl   %r14,lockdep_sys_exit
  78 #endif
  79         .endm
  80
  81         .macro  CHECK_STACK stacksize,savearea
  82 #ifdef CONFIG_CHECK_STACK
  83         tml     %r15,\stacksize - CONFIG_STACK_GUARD
  84         lghi    %r14,\savearea
  85         jz      stack_overflow
  86 #endif
  87         .endm
  88
  89         .macro  SWITCH_ASYNC savearea,timer
  90         tmhh    %r8,0x0001              # interrupting from user ?
  91         jnz     1f
  92         lgr     %r14,%r9
  93         slg     %r14,BASED(.Lcritical_start)
  94         clg     %r14,BASED(.Lcritical_length)
  95         jhe     0f
  96         lghi    %r11,\savearea          # inside critical section, do cleanup
  97         brasl   %r14,cleanup_critical
  98         tmhh    %r8,0x0001              # retest problem state after cleanup
  99         jnz     1f
 100 0:      lg      %r14,__LC_ASYNC_STACK   # are we already on the async stack?
 101         slgr    %r14,%r15
 102         srag    %r14,%r14,STACK_SHIFT
 103         jnz     2f
 104         CHECK_STACK 1<<STACK_SHIFT,\savearea
 105         aghi    %r15,-(STACK_FRAME_OVERHEAD + __PT_SIZE)
 106         j       3f
 107 1:      UPDATE_VTIME %r14,%r15,\timer
 108 2:      lg      %r15,__LC_ASYNC_STACK   # load async stack
 109 3:      la      %r11,STACK_FRAME_OVERHEAD(%r15)
 110         .endm
 111
 112         .macro UPDATE_VTIME w1,w2,enter_timer
 113         lg      \w1,__LC_EXIT_TIMER
 114         lg      \w2,__LC_LAST_UPDATE_TIMER
 115         slg     \w1,\enter_timer
 116         slg     \w2,__LC_EXIT_TIMER
 117         alg     \w1,__LC_USER_TIMER
 118         alg     \w2,__LC_SYSTEM_TIMER
 119         stg     \w1,__LC_USER_TIMER
 120         stg     \w2,__LC_SYSTEM_TIMER
 121         mvc     __LC_LAST_UPDATE_TIMER(8),\enter_timer
 122         .endm
 123
 124         .macro REENABLE_IRQS
 125         stg     %r8,__LC_RETURN_PSW
 126         ni      __LC_RETURN_PSW,0xbf
 127         ssm     __LC_RETURN_PSW
 128         .endm
 129
 130         .macro STCK savearea
 131 #ifdef CONFIG_HAVE_MARCH_Z9_109_FEATURES
 132         .insn   s,0xb27c0000,\savearea          # store clock fast
 133 #else
 134         .insn   s,0xb2050000,\savearea          # store clock
 135 #endif
 136         .endm
 137
 138         /*
 139          * The TSTMSK macro generates a test-under-mask instruction by
 140          * calculating the memory offset for the specified mask value.
 141          * Mask value can be any constant.  The macro shifts the mask
 142          * value to calculate the memory offset for the test-under-mask
 143          * instruction.
 144          */
 145         .macro TSTMSK addr, mask, size=8, bytepos=0
 146                 .if (\bytepos < \size) && (\mask >> 8)
 147                         .if (\mask & 0xff)
 148                                 .error "Mask exceeds byte boundary"
 149                         .endif
 150                         TSTMSK \addr, "(\mask >> 8)", \size, "(\bytepos + 1)"
 151                         .exitm
 152                 .endif
 153                 .ifeq \mask
 154                         .error "Mask must not be zero"
 155                 .endif
 156                 off = \size - \bytepos - 1
 157                 tm      off+\addr, \mask
 158         .endm
 159
 160         .section .kprobes.text, "ax"
 161 .Ldummy:
 162         /*
 163          * This nop exists only in order to avoid that __switch_to starts at
 164          * the beginning of the kprobes text section. In that case we would
 165          * have several symbols at the same address. E.g. objdump would take
 166          * an arbitrary symbol name when disassembling this code.
 167          * With the added nop in between the __switch_to symbol is unique
 168          * again.
 169          */
 170         nop     0
 171
 172 /*
 173  * Scheduler resume function, called by switch_to
 174  *  gpr2 = (task_struct *) prev
 175  *  gpr3 = (task_struct *) next
 176  * Returns:
 177  *  gpr2 = prev
 178  */
 179 ENTRY(__switch_to)
 180         stmg    %r6,%r15,__SF_GPRS(%r15)        # store gprs of prev task
 181         lgr     %r1,%r2
 182         aghi    %r1,__TASK_thread               # thread_struct of prev task
 183         lg      %r5,__TASK_stack(%r3)           # start of kernel stack of next
 184         stg     %r15,__THREAD_ksp(%r1)          # store kernel stack of prev
 185         lgr     %r1,%r3
 186         aghi    %r1,__TASK_thread               # thread_struct of next task
 187         lgr     %r15,%r5
 188         aghi    %r15,STACK_INIT                 # end of kernel stack of next
 189         stg     %r3,__LC_CURRENT                # store task struct of next
 190         stg     %r15,__LC_KERNEL_STACK          # store end of kernel stack
 191         lg      %r15,__THREAD_ksp(%r1)          # load kernel stack of next
 192         mvc     __LC_CURRENT_PID(4,%r0),__TASK_pid(%r3) # store pid of next
 193         lmg     %r6,%r15,__SF_GPRS(%r15)        # load gprs of next task
 194         TSTMSK  __LC_MACHINE_FLAGS,MACHINE_FLAG_LPP
 195         bzr     %r14
 196         .insn   s,0xb2800000,__LC_LPP           # set program parameter
 197         br      %r14
 198
 199 .L__critical_start:
 200
 201 #if IS_ENABLED(CONFIG_KVM)
 202 /*
 203  * sie64a calling convention:
 204  * %r2 pointer to sie control block
 205  * %r3 guest register save area
 206  */
 207 ENTRY(sie64a)
 208         stmg    %r6,%r14,__SF_GPRS(%r15)        # save kernel registers
 209         stg     %r2,__SF_EMPTY(%r15)            # save control block pointer
 210         stg     %r3,__SF_EMPTY+8(%r15)          # save guest register save area
 211         xc      __SF_EMPTY+16(8,%r15),__SF_EMPTY+16(%r15) # reason code = 0
 212         TSTMSK  __LC_CPU_FLAGS,_CIF_FPU         # load guest fp/vx registers ?
 213         jno     .Lsie_load_guest_gprs
 214         brasl   %r14,load_fpu_regs              # load guest fp/vx regs
 215 .Lsie_load_guest_gprs:
 216         lmg     %r0,%r13,0(%r3)                 # load guest gprs 0-13
 217         lg      %r14,__LC_GMAP                  # get gmap pointer
 218         ltgr    %r14,%r14
 219         jz      .Lsie_gmap
 220         lctlg   %c1,%c1,__GMAP_ASCE(%r14)       # load primary asce
 221 .Lsie_gmap:
 222         lg      %r14,__SF_EMPTY(%r15)           # get control block pointer
 223         oi      __SIE_PROG0C+3(%r14),1          # we are going into SIE now
 224         tm      __SIE_PROG20+3(%r14),3          # last exit...
 225         jnz     .Lsie_skip
 226         TSTMSK  __LC_CPU_FLAGS,_CIF_FPU
 227         jo      .Lsie_skip                      # exit if fp/vx regs changed
 228         sie     0(%r14)
 229 .Lsie_skip:
 230         ni      __SIE_PROG0C+3(%r14),0xfe       # no longer in SIE
 231         lctlg   %c1,%c1,__LC_USER_ASCE          # load primary asce
 232 .Lsie_done:
 233 # some program checks are suppressing. C code (e.g. do_protection_exception)
 234 # will rewind the PSW by the ILC, which is often 4 bytes in case of SIE. There
 235 # are some corner cases (e.g. runtime instrumentation) where ILC is unpredictable.
 236 # Other instructions between sie64a and .Lsie_done should not cause program
 237 # interrupts. So lets use 3 nops as a landing pad for all possible rewinds.
 238 # See also .Lcleanup_sie
 239 .Lrewind_pad6:
 240         nopr    7
 241 .Lrewind_pad4:
 242         nopr    7
 243 .Lrewind_pad2:
 244         nopr    7
 245         .globl sie_exit
 246 sie_exit:
 247         lg      %r14,__SF_EMPTY+8(%r15)         # load guest register save area
 248         stmg    %r0,%r13,0(%r14)                # save guest gprs 0-13
 249         lmg     %r6,%r14,__SF_GPRS(%r15)        # restore kernel registers
 250         lg      %r2,__SF_EMPTY+16(%r15)         # return exit reason code
 251         br      %r14
 252 .Lsie_fault:
 253         lghi    %r14,-EFAULT
 254         stg     %r14,__SF_EMPTY+16(%r15)        # set exit reason code
 255         j       sie_exit
 256
 257         EX_TABLE(.Lrewind_pad6,.Lsie_fault)
 258         EX_TABLE(.Lrewind_pad4,.Lsie_fault)
 259         EX_TABLE(.Lrewind_pad2,.Lsie_fault)
 260         EX_TABLE(sie_exit,.Lsie_fault)
 261 EXPORT_SYMBOL(sie64a)
 262 EXPORT_SYMBOL(sie_exit)
 263 #endif
 264
 265 /*
 266  * SVC interrupt handler routine. System calls are synchronous events and
 267  * are executed with interrupts enabled.
 268  */
 269
 270 ENTRY(system_call)
 271         stpt    __LC_SYNC_ENTER_TIMER
 272 .Lsysc_stmg:
 273         stmg    %r8,%r15,__LC_SAVE_AREA_SYNC
 274         lg      %r12,__LC_CURRENT
 275         lghi    %r13,__TASK_thread
 276         lghi    %r14,_PIF_SYSCALL
 277 .Lsysc_per:
 278         lg      %r15,__LC_KERNEL_STACK
 279         la      %r11,STACK_FRAME_OVERHEAD(%r15) # pointer to pt_regs
 280 .Lsysc_vtime:
 281         UPDATE_VTIME %r8,%r9,__LC_SYNC_ENTER_TIMER
 282         stmg    %r0,%r7,__PT_R0(%r11)
 283         mvc     __PT_R8(64,%r11),__LC_SAVE_AREA_SYNC
 284         mvc     __PT_PSW(16,%r11),__LC_SVC_OLD_PSW
 285         mvc     __PT_INT_CODE(4,%r11),__LC_SVC_ILC
 286         stg     %r14,__PT_FLAGS(%r11)
 287 .Lsysc_do_svc:
 288         # load address of system call table
 289         lg      %r10,__THREAD_sysc_table(%r13,%r12)
 290         llgh    %r8,__PT_INT_CODE+2(%r11)
 291         slag    %r8,%r8,2                       # shift and test for svc 0
 292         jnz     .Lsysc_nr_ok
 293         # svc 0: system call number in %r1
 294         llgfr   %r1,%r1                         # clear high word in r1
 295         cghi    %r1,NR_syscalls
 296         jnl     .Lsysc_nr_ok
 297         sth     %r1,__PT_INT_CODE+2(%r11)
 298         slag    %r8,%r1,2
 299 .Lsysc_nr_ok:
 300         xc      __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
 301         stg     %r2,__PT_ORIG_GPR2(%r11)
 302         stg     %r7,STACK_FRAME_OVERHEAD(%r15)
 303         lgf     %r9,0(%r8,%r10)                 # get system call add.
 304         TSTMSK  __TI_flags(%r12),_TIF_TRACE
 305         jnz     .Lsysc_tracesys
 306         basr    %r14,%r9                        # call sys_xxxx
 307         stg     %r2,__PT_R2(%r11)               # store return value
 308
 309 .Lsysc_return:
 310         LOCKDEP_SYS_EXIT
 311 .Lsysc_tif:
 312         TSTMSK  __PT_FLAGS(%r11),_PIF_WORK
 313         jnz     .Lsysc_work
 314         TSTMSK  __TI_flags(%r12),_TIF_WORK
 315         jnz     .Lsysc_work                     # check for work
 316         TSTMSK  __LC_CPU_FLAGS,_CIF_WORK
 317         jnz     .Lsysc_work
 318 .Lsysc_restore:
 319         lg      %r14,__LC_VDSO_PER_CPU
 320         lmg     %r0,%r10,__PT_R0(%r11)
 321         mvc     __LC_RETURN_PSW(16),__PT_PSW(%r11)
 322 .Lsysc_exit_timer:
 323         stpt    __LC_EXIT_TIMER
 324         mvc     __VDSO_ECTG_BASE(16,%r14),__LC_EXIT_TIMER
 325         lmg     %r11,%r15,__PT_R11(%r11)
 326         lpswe   __LC_RETURN_PSW
 327 .Lsysc_done:
 328
 329 #
 330 # One of the work bits is on. Find out which one.
 331 #
 332 .Lsysc_work:
 333         TSTMSK  __LC_CPU_FLAGS,_CIF_MCCK_PENDING
 334         jo      .Lsysc_mcck_pending
 335         TSTMSK  __TI_flags(%r12),_TIF_NEED_RESCHED
 336         jo      .Lsysc_reschedule
 337 #ifdef CONFIG_UPROBES
 338         TSTMSK  __TI_flags(%r12),_TIF_UPROBE
 339         jo      .Lsysc_uprobe_notify
 340 #endif
 341         TSTMSK  __TI_flags(%r12),_TIF_GUARDED_STORAGE
 342         jo      .Lsysc_guarded_storage
 343         TSTMSK  __PT_FLAGS(%r11),_PIF_PER_TRAP
 344         jo      .Lsysc_singlestep
 345 #ifdef CONFIG_LIVEPATCH
 346         TSTMSK  __TI_flags(%r12),_TIF_PATCH_PENDING
 347         jo      .Lsysc_patch_pending    # handle live patching just before
 348                                         # signals and possible syscall restart
 349 #endif
 350         TSTMSK  __TI_flags(%r12),_TIF_SIGPENDING
 351         jo      .Lsysc_sigpending
 352         TSTMSK  __TI_flags(%r12),_TIF_NOTIFY_RESUME
 353         jo      .Lsysc_notify_resume
 354         TSTMSK  __LC_CPU_FLAGS,_CIF_FPU
 355         jo      .Lsysc_vxrs
 356         TSTMSK  __LC_CPU_FLAGS,(_CIF_ASCE_PRIMARY|_CIF_ASCE_SECONDARY)
 357         jnz     .Lsysc_asce
 358         j       .Lsysc_return           # beware of critical section cleanup
 359
 360 #
 361 # _TIF_NEED_RESCHED is set, call schedule
 362 #
 363 .Lsysc_reschedule:
 364         larl    %r14,.Lsysc_return
 365         jg      schedule
 366
 367 #
 368 # _CIF_MCCK_PENDING is set, call handler
 369 #
 370 .Lsysc_mcck_pending:
 371         larl    %r14,.Lsysc_return
 372         jg      s390_handle_mcck        # TIF bit will be cleared by handler
 373
 374 #
 375 # _CIF_ASCE_PRIMARY and/or CIF_ASCE_SECONDARY set, load user space asce
 376 #
 377 .Lsysc_asce:
 378         ni      __LC_CPU_FLAGS+7,255-_CIF_ASCE_PRIMARY
 379         lctlg   %c1,%c1,__LC_USER_ASCE          # load primary asce
 380         TSTMSK  __LC_CPU_FLAGS,_CIF_ASCE_SECONDARY
 381         jz      .Lsysc_return
 382         larl    %r14,.Lsysc_return
 383         jg      set_fs_fixup
 384
 385 #
 386 # CIF_FPU is set, restore floating-point controls and floating-point registers.
 387 #
 388 .Lsysc_vxrs:
 389         larl    %r14,.Lsysc_return
 390         jg      load_fpu_regs
 391
 392 #
 393 # _TIF_SIGPENDING is set, call do_signal
 394 #
 395 .Lsysc_sigpending:
 396         lgr     %r2,%r11                # pass pointer to pt_regs
 397         brasl   %r14,do_signal
 398         TSTMSK  __PT_FLAGS(%r11),_PIF_SYSCALL
 399         jno     .Lsysc_return
 400 .Lsysc_do_syscall:
 401         lghi    %r13,__TASK_thread
 402         lmg     %r2,%r7,__PT_R2(%r11)   # load svc arguments
 403         lghi    %r1,0                   # svc 0 returns -ENOSYS
 404         j       .Lsysc_do_svc
 405
 406 #
 407 # _TIF_NOTIFY_RESUME is set, call do_notify_resume
 408 #
 409 .Lsysc_notify_resume:
 410         lgr     %r2,%r11                # pass pointer to pt_regs
 411         larl    %r14,.Lsysc_return
 412         jg      do_notify_resume
 413
 414 #
 415 # _TIF_UPROBE is set, call uprobe_notify_resume
 416 #
 417 #ifdef CONFIG_UPROBES
 418 .Lsysc_uprobe_notify:
 419         lgr     %r2,%r11                # pass pointer to pt_regs
 420         larl    %r14,.Lsysc_return
 421         jg      uprobe_notify_resume
 422 #endif
 423
 424 #
 425 # _TIF_GUARDED_STORAGE is set, call guarded_storage_load
 426 #
 427 .Lsysc_guarded_storage:
 428         lgr     %r2,%r11                # pass pointer to pt_regs
 429         larl    %r14,.Lsysc_return
 430         jg      gs_load_bc_cb
 431 #
 432 # _TIF_PATCH_PENDING is set, call klp_update_patch_state
 433 #
 434 #ifdef CONFIG_LIVEPATCH
 435 .Lsysc_patch_pending:
 436         lg      %r2,__LC_CURRENT        # pass pointer to task struct
 437         larl    %r14,.Lsysc_return
 438         jg      klp_update_patch_state
 439 #endif
 440
 441 #
 442 # _PIF_PER_TRAP is set, call do_per_trap
 443 #
 444 .Lsysc_singlestep:
 445         ni      __PT_FLAGS+7(%r11),255-_PIF_PER_TRAP
 446         lgr     %r2,%r11                # pass pointer to pt_regs
 447         larl    %r14,.Lsysc_return
 448         jg      do_per_trap
 449
 450 #
 451 # call tracehook_report_syscall_entry/tracehook_report_syscall_exit before
 452 # and after the system call
 453 #
 454 .Lsysc_tracesys:
 455         lgr     %r2,%r11                # pass pointer to pt_regs
 456         la      %r3,0
 457         llgh    %r0,__PT_INT_CODE+2(%r11)
 458         stg     %r0,__PT_R2(%r11)
 459         brasl   %r14,do_syscall_trace_enter
 460         lghi    %r0,NR_syscalls
 461         clgr    %r0,%r2
 462         jnh     .Lsysc_tracenogo
 463         sllg    %r8,%r2,2
 464         lgf     %r9,0(%r8,%r10)
 465 .Lsysc_tracego:
 466         lmg     %r3,%r7,__PT_R3(%r11)
 467         stg     %r7,STACK_FRAME_OVERHEAD(%r15)
 468         lg      %r2,__PT_ORIG_GPR2(%r11)
 469         basr    %r14,%r9                # call sys_xxx
 470         stg     %r2,__PT_R2(%r11)       # store return value
 471 .Lsysc_tracenogo:
 472         TSTMSK  __TI_flags(%r12),_TIF_TRACE
 473         jz      .Lsysc_return
 474         lgr     %r2,%r11                # pass pointer to pt_regs
 475         larl    %r14,.Lsysc_return
 476         jg      do_syscall_trace_exit
 477
 478 #
 479 # a new process exits the kernel with ret_from_fork
 480 #
 481 ENTRY(ret_from_fork)
 482         la      %r11,STACK_FRAME_OVERHEAD(%r15)
 483         lg      %r12,__LC_CURRENT
 484         brasl   %r14,schedule_tail
 485         TRACE_IRQS_ON
 486         ssm     __LC_SVC_NEW_PSW        # reenable interrupts
 487         tm      __PT_PSW+1(%r11),0x01   # forking a kernel thread ?
 488         jne     .Lsysc_tracenogo
 489         # it's a kernel thread
 490         lmg     %r9,%r10,__PT_R9(%r11)  # load gprs
 491 ENTRY(kernel_thread_starter)
 492         la      %r2,0(%r10)
 493         basr    %r14,%r9
 494         j       .Lsysc_tracenogo
 495
 496 /*
 497  * Program check handler routine
 498  */
 499
 500 ENTRY(pgm_check_handler)
 501         stpt    __LC_SYNC_ENTER_TIMER
 502         stmg    %r8,%r15,__LC_SAVE_AREA_SYNC
 503         lg      %r10,__LC_LAST_BREAK
 504         lg      %r12,__LC_CURRENT
 505         larl    %r13,cleanup_critical
 506         lmg     %r8,%r9,__LC_PGM_OLD_PSW
 507         tmhh    %r8,0x0001              # test problem state bit
 508         jnz     2f                      # -> fault in user space
 509 #if IS_ENABLED(CONFIG_KVM)
 510         # cleanup critical section for sie64a
 511         lgr     %r14,%r9
 512         slg     %r14,BASED(.Lsie_critical_start)
 513         clg     %r14,BASED(.Lsie_critical_length)
 514         jhe     0f
 515         brasl   %r14,.Lcleanup_sie
 516 #endif
 517 0:      tmhh    %r8,0x4000              # PER bit set in old PSW ?
 518         jnz     1f                      # -> enabled, can't be a double fault
 519         tm      __LC_PGM_ILC+3,0x80     # check for per exception
 520         jnz     .Lpgm_svcper            # -> single stepped svc
 521 1:      CHECK_STACK STACK_SIZE,__LC_SAVE_AREA_SYNC
 522         aghi    %r15,-(STACK_FRAME_OVERHEAD + __PT_SIZE)
 523         j       4f
 524 2:      UPDATE_VTIME %r14,%r15,__LC_SYNC_ENTER_TIMER
 525         lg      %r15,__LC_KERNEL_STACK
 526         lgr     %r14,%r12
 527         aghi    %r14,__TASK_thread      # pointer to thread_struct
 528         lghi    %r13,__LC_PGM_TDB
 529         tm      __LC_PGM_ILC+2,0x02     # check for transaction abort
 530         jz      3f
 531         mvc     __THREAD_trap_tdb(256,%r14),0(%r13)
 532 3:      stg     %r10,__THREAD_last_break(%r14)
 533 4:      la      %r11,STACK_FRAME_OVERHEAD(%r15)
 534         stmg    %r0,%r7,__PT_R0(%r11)
 535         mvc     __PT_R8(64,%r11),__LC_SAVE_AREA_SYNC
 536         stmg    %r8,%r9,__PT_PSW(%r11)
 537         mvc     __PT_INT_CODE(4,%r11),__LC_PGM_ILC
 538         mvc     __PT_INT_PARM_LONG(8,%r11),__LC_TRANS_EXC_CODE
 539         xc      __PT_FLAGS(8,%r11),__PT_FLAGS(%r11)
 540         stg     %r10,__PT_ARGS(%r11)
 541         tm      __LC_PGM_ILC+3,0x80     # check for per exception
 542         jz      5f
 543         tmhh    %r8,0x0001              # kernel per event ?
 544         jz      .Lpgm_kprobe
 545         oi      __PT_FLAGS+7(%r11),_PIF_PER_TRAP
 546         mvc     __THREAD_per_address(8,%r14),__LC_PER_ADDRESS
 547         mvc     __THREAD_per_cause(2,%r14),__LC_PER_CODE
 548         mvc     __THREAD_per_paid(1,%r14),__LC_PER_ACCESS_ID
 549 5:      REENABLE_IRQS
 550         xc      __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
 551         larl    %r1,pgm_check_table
 552         llgh    %r10,__PT_INT_CODE+2(%r11)
 553         nill    %r10,0x007f
 554         sll     %r10,2
 555         je      .Lpgm_return
 556         lgf     %r1,0(%r10,%r1)         # load address of handler routine
 557         lgr     %r2,%r11                # pass pointer to pt_regs
 558         basr    %r14,%r1                # branch to interrupt-handler
 559 .Lpgm_return:
 560         LOCKDEP_SYS_EXIT
 561         tm      __PT_PSW+1(%r11),0x01   # returning to user ?
 562         jno     .Lsysc_restore
 563         TSTMSK  __PT_FLAGS(%r11),_PIF_SYSCALL
 564         jo      .Lsysc_do_syscall
 565         j       .Lsysc_tif
 566
 567 #
 568 # PER event in supervisor state, must be kprobes
 569 #
 570 .Lpgm_kprobe:
 571         REENABLE_IRQS
 572         xc      __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
 573         lgr     %r2,%r11                # pass pointer to pt_regs
 574         brasl   %r14,do_per_trap
 575         j       .Lpgm_return
 576
 577 #
 578 # single stepped system call
 579 #
 580 .Lpgm_svcper:
 581         mvc     __LC_RETURN_PSW(8),__LC_SVC_NEW_PSW
 582         lghi    %r13,__TASK_thread
 583         larl    %r14,.Lsysc_per
 584         stg     %r14,__LC_RETURN_PSW+8
 585         lghi    %r14,_PIF_SYSCALL | _PIF_PER_TRAP
 586         lpswe   __LC_RETURN_PSW         # branch to .Lsysc_per and enable irqs
 587
 588 /*
 589  * IO interrupt handler routine
 590  */
 591 ENTRY(io_int_handler)
 592         STCK    __LC_INT_CLOCK
 593         stpt    __LC_ASYNC_ENTER_TIMER
 594         stmg    %r8,%r15,__LC_SAVE_AREA_ASYNC
 595         lg      %r12,__LC_CURRENT
 596         larl    %r13,cleanup_critical
 597         lmg     %r8,%r9,__LC_IO_OLD_PSW
 598         SWITCH_ASYNC __LC_SAVE_AREA_ASYNC,__LC_ASYNC_ENTER_TIMER
 599         stmg    %r0,%r7,__PT_R0(%r11)
 600         mvc     __PT_R8(64,%r11),__LC_SAVE_AREA_ASYNC
 601         stmg    %r8,%r9,__PT_PSW(%r11)
 602         mvc     __PT_INT_CODE(12,%r11),__LC_SUBCHANNEL_ID
 603         xc      __PT_FLAGS(8,%r11),__PT_FLAGS(%r11)
 604         TSTMSK  __LC_CPU_FLAGS,_CIF_IGNORE_IRQ
 605         jo      .Lio_restore
 606         TRACE_IRQS_OFF
 607         xc      __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
 608 .Lio_loop:
 609         lgr     %r2,%r11                # pass pointer to pt_regs
 610         lghi    %r3,IO_INTERRUPT
 611         tm      __PT_INT_CODE+8(%r11),0x80      # adapter interrupt ?
 612         jz      .Lio_call
 613         lghi    %r3,THIN_INTERRUPT
 614 .Lio_call:
 615         brasl   %r14,do_IRQ
 616         TSTMSK  __LC_MACHINE_FLAGS,MACHINE_FLAG_LPAR
 617         jz      .Lio_return
 618         tpi     0
 619         jz      .Lio_return
 620         mvc     __PT_INT_CODE(12,%r11),__LC_SUBCHANNEL_ID
 621         j       .Lio_loop
 622 .Lio_return:
 623         LOCKDEP_SYS_EXIT
 624         TRACE_IRQS_ON
 625 .Lio_tif:
 626         TSTMSK  __TI_flags(%r12),_TIF_WORK
 627         jnz     .Lio_work               # there is work to do (signals etc.)
 628         TSTMSK  __LC_CPU_FLAGS,_CIF_WORK
 629         jnz     .Lio_work
 630 .Lio_restore:
 631         lg      %r14,__LC_VDSO_PER_CPU
 632         lmg     %r0,%r10,__PT_R0(%r11)
 633         mvc     __LC_RETURN_PSW(16),__PT_PSW(%r11)
 634 .Lio_exit_timer:
 635         stpt    __LC_EXIT_TIMER
 636         mvc     __VDSO_ECTG_BASE(16,%r14),__LC_EXIT_TIMER
 637         lmg     %r11,%r15,__PT_R11(%r11)
 638         lpswe   __LC_RETURN_PSW
 639 .Lio_done:
 640
 641 #
 642 # There is work todo, find out in which context we have been interrupted:
 643 # 1) if we return to user space we can do all _TIF_WORK work
 644 # 2) if we return to kernel code and kvm is enabled check if we need to
 645 #    modify the psw to leave SIE
 646 # 3) if we return to kernel code and preemptive scheduling is enabled check
 647 #    the preemption counter and if it is zero call preempt_schedule_irq
 648 # Before any work can be done, a switch to the kernel stack is required.
 649 #
 650 .Lio_work:
 651         tm      __PT_PSW+1(%r11),0x01   # returning to user ?
 652         jo      .Lio_work_user          # yes -> do resched & signal
 653 #ifdef CONFIG_PREEMPT
 654         # check for preemptive scheduling
 655         icm     %r0,15,__LC_PREEMPT_COUNT
 656         jnz     .Lio_restore            # preemption is disabled
 657         TSTMSK  __TI_flags(%r12),_TIF_NEED_RESCHED
 658         jno     .Lio_restore
 659         # switch to kernel stack
 660         lg      %r1,__PT_R15(%r11)
 661         aghi    %r1,-(STACK_FRAME_OVERHEAD + __PT_SIZE)
 662         mvc     STACK_FRAME_OVERHEAD(__PT_SIZE,%r1),0(%r11)
 663         xc      __SF_BACKCHAIN(8,%r1),__SF_BACKCHAIN(%r1)
 664         la      %r11,STACK_FRAME_OVERHEAD(%r1)
 665         lgr     %r15,%r1
 666         # TRACE_IRQS_ON already done at .Lio_return, call
 667         # TRACE_IRQS_OFF to keep things symmetrical
 668         TRACE_IRQS_OFF
 669         brasl   %r14,preempt_schedule_irq
 670         j       .Lio_return
 671 #else
 672         j       .Lio_restore
 673 #endif
 674
 675 #
 676 # Need to do work before returning to userspace, switch to kernel stack
 677 #
 678 .Lio_work_user:
 679         lg      %r1,__LC_KERNEL_STACK
 680         mvc     STACK_FRAME_OVERHEAD(__PT_SIZE,%r1),0(%r11)
 681         xc      __SF_BACKCHAIN(8,%r1),__SF_BACKCHAIN(%r1)
 682         la      %r11,STACK_FRAME_OVERHEAD(%r1)
 683         lgr     %r15,%r1
 684
 685 #
 686 # One of the work bits is on. Find out which one.
 687 #
 688 .Lio_work_tif:
 689         TSTMSK  __LC_CPU_FLAGS,_CIF_MCCK_PENDING
 690         jo      .Lio_mcck_pending
 691         TSTMSK  __TI_flags(%r12),_TIF_NEED_RESCHED
 692         jo      .Lio_reschedule
 693 #ifdef CONFIG_LIVEPATCH
 694         TSTMSK  __TI_flags(%r12),_TIF_PATCH_PENDING
 695         jo      .Lio_patch_pending
 696 #endif
 697         TSTMSK  __TI_flags(%r12),_TIF_SIGPENDING
 698         jo      .Lio_sigpending
 699         TSTMSK  __TI_flags(%r12),_TIF_NOTIFY_RESUME
 700         jo      .Lio_notify_resume
 701         TSTMSK  __TI_flags(%r12),_TIF_GUARDED_STORAGE
 702         jo      .Lio_guarded_storage
 703         TSTMSK  __LC_CPU_FLAGS,_CIF_FPU
 704         jo      .Lio_vxrs
 705         TSTMSK  __LC_CPU_FLAGS,(_CIF_ASCE_PRIMARY|_CIF_ASCE_SECONDARY)
 706         jnz     .Lio_asce
 707         j       .Lio_return             # beware of critical section cleanup
 708
 709 #
 710 # _CIF_MCCK_PENDING is set, call handler
 711 #
 712 .Lio_mcck_pending:
 713         # TRACE_IRQS_ON already done at .Lio_return
 714         brasl   %r14,s390_handle_mcck   # TIF bit will be cleared by handler
 715         TRACE_IRQS_OFF
 716         j       .Lio_return
 717
 718 #
 719 # _CIF_ASCE_PRIMARY and/or CIF_ASCE_SECONDARY set, load user space asce
 720 #
 721 .Lio_asce:
 722         ni      __LC_CPU_FLAGS+7,255-_CIF_ASCE_PRIMARY
 723         lctlg   %c1,%c1,__LC_USER_ASCE          # load primary asce
 724         TSTMSK  __LC_CPU_FLAGS,_CIF_ASCE_SECONDARY
 725         jz      .Lio_return
 726         larl    %r14,.Lio_return
 727         jg      set_fs_fixup
 728
 729 #
 730 # CIF_FPU is set, restore floating-point controls and floating-point registers.
 731 #
 732 .Lio_vxrs:
 733         larl    %r14,.Lio_return
 734         jg      load_fpu_regs
 735
 736 #
 737 # _TIF_GUARDED_STORAGE is set, call guarded_storage_load
 738 #
 739 .Lio_guarded_storage:
 740         # TRACE_IRQS_ON already done at .Lio_return
 741         ssm     __LC_SVC_NEW_PSW        # reenable interrupts
 742         lgr     %r2,%r11                # pass pointer to pt_regs
 743         brasl   %r14,gs_load_bc_cb
 744         ssm     __LC_PGM_NEW_PSW        # disable I/O and ext. interrupts
 745         TRACE_IRQS_OFF
 746         j       .Lio_return
 747
 748 #
 749 # _TIF_NEED_RESCHED is set, call schedule
 750 #
 751 .Lio_reschedule:
 752         # TRACE_IRQS_ON already done at .Lio_return
 753         ssm     __LC_SVC_NEW_PSW        # reenable interrupts
 754         brasl   %r14,schedule           # call scheduler
 755         ssm     __LC_PGM_NEW_PSW        # disable I/O and ext. interrupts
 756         TRACE_IRQS_OFF
 757         j       .Lio_return
 758
 759 #
 760 # _TIF_PATCH_PENDING is set, call klp_update_patch_state
 761 #
 762 #ifdef CONFIG_LIVEPATCH
 763 .Lio_patch_pending:
 764         lg      %r2,__LC_CURRENT        # pass pointer to task struct
 765         larl    %r14,.Lio_return
 766         jg      klp_update_patch_state
 767 #endif
 768
 769 #
 770 # _TIF_SIGPENDING or is set, call do_signal
 771 #
 772 .Lio_sigpending:
 773         # TRACE_IRQS_ON already done at .Lio_return
 774         ssm     __LC_SVC_NEW_PSW        # reenable interrupts
 775         lgr     %r2,%r11                # pass pointer to pt_regs
 776         brasl   %r14,do_signal
 777         ssm     __LC_PGM_NEW_PSW        # disable I/O and ext. interrupts
 778         TRACE_IRQS_OFF
 779         j       .Lio_return
 780
 781 #
 782 # _TIF_NOTIFY_RESUME or is set, call do_notify_resume
 783 #
 784 .Lio_notify_resume:
 785         # TRACE_IRQS_ON already done at .Lio_return
 786         ssm     __LC_SVC_NEW_PSW        # reenable interrupts
 787         lgr     %r2,%r11                # pass pointer to pt_regs
 788         brasl   %r14,do_notify_resume
 789         ssm     __LC_PGM_NEW_PSW        # disable I/O and ext. interrupts
 790         TRACE_IRQS_OFF
 791         j       .Lio_return
 792
 793 /*
 794  * External interrupt handler routine
 795  */
 796 ENTRY(ext_int_handler)
 797         STCK    __LC_INT_CLOCK
 798         stpt    __LC_ASYNC_ENTER_TIMER
 799         stmg    %r8,%r15,__LC_SAVE_AREA_ASYNC
 800         lg      %r12,__LC_CURRENT
 801         larl    %r13,cleanup_critical
 802         lmg     %r8,%r9,__LC_EXT_OLD_PSW
 803         SWITCH_ASYNC __LC_SAVE_AREA_ASYNC,__LC_ASYNC_ENTER_TIMER
 804         stmg    %r0,%r7,__PT_R0(%r11)
 805         mvc     __PT_R8(64,%r11),__LC_SAVE_AREA_ASYNC
 806         stmg    %r8,%r9,__PT_PSW(%r11)
 807         lghi    %r1,__LC_EXT_PARAMS2
 808         mvc     __PT_INT_CODE(4,%r11),__LC_EXT_CPU_ADDR
 809         mvc     __PT_INT_PARM(4,%r11),__LC_EXT_PARAMS
 810         mvc     __PT_INT_PARM_LONG(8,%r11),0(%r1)
 811         xc      __PT_FLAGS(8,%r11),__PT_FLAGS(%r11)
 812         TSTMSK  __LC_CPU_FLAGS,_CIF_IGNORE_IRQ
 813         jo      .Lio_restore
 814         TRACE_IRQS_OFF
 815         xc      __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
 816         lgr     %r2,%r11                # pass pointer to pt_regs
 817         lghi    %r3,EXT_INTERRUPT
 818         brasl   %r14,do_IRQ
 819         j       .Lio_return
 820
 821 /*
 822  * Load idle PSW. The second "half" of this function is in .Lcleanup_idle.
 823  */
 824 ENTRY(psw_idle)
 825         stg     %r3,__SF_EMPTY(%r15)
 826         larl    %r1,.Lpsw_idle_lpsw+4
 827         stg     %r1,__SF_EMPTY+8(%r15)
 828 #ifdef CONFIG_SMP
 829         larl    %r1,smp_cpu_mtid
 830         llgf    %r1,0(%r1)
 831         ltgr    %r1,%r1
 832         jz      .Lpsw_idle_stcctm
 833         .insn   rsy,0xeb0000000017,%r1,5,__SF_EMPTY+16(%r15)
 834 .Lpsw_idle_stcctm:
 835 #endif
 836         oi      __LC_CPU_FLAGS+7,_CIF_ENABLED_WAIT
 837         STCK    __CLOCK_IDLE_ENTER(%r2)
 838         stpt    __TIMER_IDLE_ENTER(%r2)
 839 .Lpsw_idle_lpsw:
 840         lpswe   __SF_EMPTY(%r15)
 841         br      %r14
 842 .Lpsw_idle_end:
 843
 844 /*
 845  * Store floating-point controls and floating-point or vector register
 846  * depending whether the vector facility is available.  A critical section
 847  * cleanup assures that the registers are stored even if interrupted for
 848  * some other work.  The CIF_FPU flag is set to trigger a lazy restore
 849  * of the register contents at return from io or a system call.
 850  */
 851 ENTRY(save_fpu_regs)
 852         lg      %r2,__LC_CURRENT
 853         aghi    %r2,__TASK_thread
 854         TSTMSK  __LC_CPU_FLAGS,_CIF_FPU
 855         bor     %r14
 856         stfpc   __THREAD_FPU_fpc(%r2)
 857         lg      %r3,__THREAD_FPU_regs(%r2)
 858         TSTMSK  __LC_MACHINE_FLAGS,MACHINE_FLAG_VX
 859         jz      .Lsave_fpu_regs_fp        # no -> store FP regs
 860         VSTM    %v0,%v15,0,%r3            # vstm 0,15,0(3)
 861         VSTM    %v16,%v31,256,%r3         # vstm 16,31,256(3)
 862         j       .Lsave_fpu_regs_done      # -> set CIF_FPU flag
 863 .Lsave_fpu_regs_fp:
 864         std     0,0(%r3)
 865         std     1,8(%r3)
 866         std     2,16(%r3)
 867         std     3,24(%r3)
 868         std     4,32(%r3)
 869         std     5,40(%r3)
 870         std     6,48(%r3)
 871         std     7,56(%r3)
 872         std     8,64(%r3)
 873         std     9,72(%r3)
 874         std     10,80(%r3)
 875         std     11,88(%r3)
 876         std     12,96(%r3)
 877         std     13,104(%r3)
 878         std     14,112(%r3)
 879         std     15,120(%r3)
 880 .Lsave_fpu_regs_done:
 881         oi      __LC_CPU_FLAGS+7,_CIF_FPU
 882         br      %r14
 883 .Lsave_fpu_regs_end:
 884 #if IS_ENABLED(CONFIG_KVM)
 885 EXPORT_SYMBOL(save_fpu_regs)
 886 #endif
 887
 888 /*
 889  * Load floating-point controls and floating-point or vector registers.
 890  * A critical section cleanup assures that the register contents are
 891  * loaded even if interrupted for some other work.
 892  *
 893  * There are special calling conventions to fit into sysc and io return work:
 894  *      %r15:   <kernel stack>
 895  * The function requires:
 896  *      %r4
 897  */
 898 load_fpu_regs:
 899         lg      %r4,__LC_CURRENT
 900         aghi    %r4,__TASK_thread
 901         TSTMSK  __LC_CPU_FLAGS,_CIF_FPU
 902         bnor    %r14
 903         lfpc    __THREAD_FPU_fpc(%r4)
 904         TSTMSK  __LC_MACHINE_FLAGS,MACHINE_FLAG_VX
 905         lg      %r4,__THREAD_FPU_regs(%r4)      # %r4 <- reg save area
 906         jz      .Lload_fpu_regs_fp              # -> no VX, load FP regs
 907         VLM     %v0,%v15,0,%r4
 908         VLM     %v16,%v31,256,%r4
 909         j       .Lload_fpu_regs_done
 910 .Lload_fpu_regs_fp:
 911         ld      0,0(%r4)
 912         ld      1,8(%r4)
 913         ld      2,16(%r4)
 914         ld      3,24(%r4)
 915         ld      4,32(%r4)
 916         ld      5,40(%r4)
 917         ld      6,48(%r4)
 918         ld      7,56(%r4)
 919         ld      8,64(%r4)
 920         ld      9,72(%r4)
 921         ld      10,80(%r4)
 922         ld      11,88(%r4)
 923         ld      12,96(%r4)
 924         ld      13,104(%r4)
 925         ld      14,112(%r4)
 926         ld      15,120(%r4)
 927 .Lload_fpu_regs_done:
 928         ni      __LC_CPU_FLAGS+7,255-_CIF_FPU
 929         br      %r14
 930 .Lload_fpu_regs_end:
 931
 932 .L__critical_end:
 933
 934 /*
 935  * Machine check handler routines
 936  */
 937 ENTRY(mcck_int_handler)
 938         STCK    __LC_MCCK_CLOCK
 939         la      %r1,4095                # revalidate r1
 940         spt     __LC_CPU_TIMER_SAVE_AREA-4095(%r1)      # revalidate cpu timer
 941         lmg     %r0,%r15,__LC_GPREGS_SAVE_AREA-4095(%r1)# revalidate gprs
 942         lg      %r12,__LC_CURRENT
 943         larl    %r13,cleanup_critical
 944         lmg     %r8,%r9,__LC_MCK_OLD_PSW
 945         TSTMSK  __LC_MCCK_CODE,MCCK_CODE_SYSTEM_DAMAGE
 946         jo      .Lmcck_panic            # yes -> rest of mcck code invalid
 947         lghi    %r14,__LC_CPU_TIMER_SAVE_AREA
 948         mvc     __LC_MCCK_ENTER_TIMER(8),0(%r14)
 949         TSTMSK  __LC_MCCK_CODE,MCCK_CODE_CPU_TIMER_VALID
 950         jo      3f
 951         la      %r14,__LC_SYNC_ENTER_TIMER
 952         clc     0(8,%r14),__LC_ASYNC_ENTER_TIMER
 953         jl      0f
 954         la      %r14,__LC_ASYNC_ENTER_TIMER
 955 0:      clc     0(8,%r14),__LC_EXIT_TIMER
 956         jl      1f
 957         la      %r14,__LC_EXIT_TIMER
 958 1:      clc     0(8,%r14),__LC_LAST_UPDATE_TIMER
 959         jl      2f
 960         la      %r14,__LC_LAST_UPDATE_TIMER
 961 2:      spt     0(%r14)
 962         mvc     __LC_MCCK_ENTER_TIMER(8),0(%r14)
 963 3:      TSTMSK  __LC_MCCK_CODE,(MCCK_CODE_PSW_MWP_VALID|MCCK_CODE_PSW_IA_VALID)
 964         jno     .Lmcck_panic            # no -> skip cleanup critical
 965         SWITCH_ASYNC __LC_GPREGS_SAVE_AREA+64,__LC_MCCK_ENTER_TIMER
 966 .Lmcck_skip:
 967         lghi    %r14,__LC_GPREGS_SAVE_AREA+64
 968         stmg    %r0,%r7,__PT_R0(%r11)
 969         mvc     __PT_R8(64,%r11),0(%r14)
 970         stmg    %r8,%r9,__PT_PSW(%r11)
 971         xc      __PT_FLAGS(8,%r11),__PT_FLAGS(%r11)
 972         xc      __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
 973         lgr     %r2,%r11                # pass pointer to pt_regs
 974         brasl   %r14,s390_do_machine_check
 975         tm      __PT_PSW+1(%r11),0x01   # returning to user ?
 976         jno     .Lmcck_return
 977         lg      %r1,__LC_KERNEL_STACK   # switch to kernel stack
 978         mvc     STACK_FRAME_OVERHEAD(__PT_SIZE,%r1),0(%r11)
 979         xc      __SF_BACKCHAIN(8,%r1),__SF_BACKCHAIN(%r1)
 980         la      %r11,STACK_FRAME_OVERHEAD(%r1)
 981         lgr     %r15,%r1
 982         ssm     __LC_PGM_NEW_PSW        # turn dat on, keep irqs off
 983         TSTMSK  __LC_CPU_FLAGS,_CIF_MCCK_PENDING
 984         jno     .Lmcck_return
 985         TRACE_IRQS_OFF
 986         brasl   %r14,s390_handle_mcck
 987         TRACE_IRQS_ON
 988 .Lmcck_return:
 989         lg      %r14,__LC_VDSO_PER_CPU
 990         lmg     %r0,%r10,__PT_R0(%r11)
 991         mvc     __LC_RETURN_MCCK_PSW(16),__PT_PSW(%r11) # move return PSW
 992         tm      __LC_RETURN_MCCK_PSW+1,0x01 # returning to user ?
 993         jno     0f
 994         stpt    __LC_EXIT_TIMER
 995         mvc     __VDSO_ECTG_BASE(16,%r14),__LC_EXIT_TIMER
 996 0:      lmg     %r11,%r15,__PT_R11(%r11)
 997         lpswe   __LC_RETURN_MCCK_PSW
 998
 999 .Lmcck_panic:
1000         lg      %r15,__LC_PANIC_STACK
1001         la      %r11,STACK_FRAME_OVERHEAD(%r15)
1002         j       .Lmcck_skip
1003
1004 #
1005 # PSW restart interrupt handler
1006 #
1007 ENTRY(restart_int_handler)
1008         TSTMSK  __LC_MACHINE_FLAGS,MACHINE_FLAG_LPP
1009         jz      0f
1010         .insn   s,0xb2800000,__LC_LPP
1011 0:      stg     %r15,__LC_SAVE_AREA_RESTART
1012         lg      %r15,__LC_RESTART_STACK
1013         aghi    %r15,-__PT_SIZE                 # create pt_regs on stack
1014         xc      0(__PT_SIZE,%r15),0(%r15)
1015         stmg    %r0,%r14,__PT_R0(%r15)
1016         mvc     __PT_R15(8,%r15),__LC_SAVE_AREA_RESTART
1017         mvc     __PT_PSW(16,%r15),__LC_RST_OLD_PSW # store restart old psw
1018         aghi    %r15,-STACK_FRAME_OVERHEAD      # create stack frame on stack
1019         xc      0(STACK_FRAME_OVERHEAD,%r15),0(%r15)
1020         lg      %r1,__LC_RESTART_FN             # load fn, parm & source cpu
1021         lg      %r2,__LC_RESTART_DATA
1022         lg      %r3,__LC_RESTART_SOURCE
1023         ltgr    %r3,%r3                         # test source cpu address
1024         jm      1f                              # negative -> skip source stop
1025 0:      sigp    %r4,%r3,SIGP_SENSE              # sigp sense to source cpu
1026         brc     10,0b                           # wait for status stored
1027 1:      basr    %r14,%r1                        # call function
1028         stap    __SF_EMPTY(%r15)                # store cpu address
1029         llgh    %r3,__SF_EMPTY(%r15)
1030 2:      sigp    %r4,%r3,SIGP_STOP               # sigp stop to current cpu
1031         brc     2,2b
1032 3:      j       3b
1033
1034         .section .kprobes.text, "ax"
1035
1036 #ifdef CONFIG_CHECK_STACK
1037 /*
1038  * The synchronous or the asynchronous stack overflowed. We are dead.
1039  * No need to properly save the registers, we are going to panic anyway.
1040  * Setup a pt_regs so that show_trace can provide a good call trace.
1041  */
1042 stack_overflow:
1043         lg      %r15,__LC_PANIC_STACK   # change to panic stack
1044         la      %r11,STACK_FRAME_OVERHEAD(%r15)
1045         stmg    %r0,%r7,__PT_R0(%r11)
1046         stmg    %r8,%r9,__PT_PSW(%r11)
1047         mvc     __PT_R8(64,%r11),0(%r14)
1048         stg     %r10,__PT_ORIG_GPR2(%r11) # store last break to orig_gpr2
1049         xc      __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
1050         lgr     %r2,%r11                # pass pointer to pt_regs
1051         jg      kernel_stack_overflow
1052 #endif
1053
1054 cleanup_critical:
1055 #if IS_ENABLED(CONFIG_KVM)
1056         clg     %r9,BASED(.Lcleanup_table_sie)  # .Lsie_gmap
1057         jl      0f
1058         clg     %r9,BASED(.Lcleanup_table_sie+8)# .Lsie_done
1059         jl      .Lcleanup_sie
1060 #endif
1061         clg     %r9,BASED(.Lcleanup_table)      # system_call
1062         jl      0f
1063         clg     %r9,BASED(.Lcleanup_table+8)    # .Lsysc_do_svc
1064         jl      .Lcleanup_system_call
1065         clg     %r9,BASED(.Lcleanup_table+16)   # .Lsysc_tif
1066         jl      0f
1067         clg     %r9,BASED(.Lcleanup_table+24)   # .Lsysc_restore
1068         jl      .Lcleanup_sysc_tif
1069         clg     %r9,BASED(.Lcleanup_table+32)   # .Lsysc_done
1070         jl      .Lcleanup_sysc_restore
1071         clg     %r9,BASED(.Lcleanup_table+40)   # .Lio_tif
1072         jl      0f
1073         clg     %r9,BASED(.Lcleanup_table+48)   # .Lio_restore
1074         jl      .Lcleanup_io_tif
1075         clg     %r9,BASED(.Lcleanup_table+56)   # .Lio_done
1076         jl      .Lcleanup_io_restore
1077         clg     %r9,BASED(.Lcleanup_table+64)   # psw_idle
1078         jl      0f
1079         clg     %r9,BASED(.Lcleanup_table+72)   # .Lpsw_idle_end
1080         jl      .Lcleanup_idle
1081         clg     %r9,BASED(.Lcleanup_table+80)   # save_fpu_regs
1082         jl      0f
1083         clg     %r9,BASED(.Lcleanup_table+88)   # .Lsave_fpu_regs_end
1084         jl      .Lcleanup_save_fpu_regs
1085         clg     %r9,BASED(.Lcleanup_table+96)   # load_fpu_regs
1086         jl      0f
1087         clg     %r9,BASED(.Lcleanup_table+104)  # .Lload_fpu_regs_end
1088         jl      .Lcleanup_load_fpu_regs
1089 0:      br      %r14
1090
1091         .align  8
1092 .Lcleanup_table:
1093         .quad   system_call
1094         .quad   .Lsysc_do_svc
1095         .quad   .Lsysc_tif
1096         .quad   .Lsysc_restore
1097         .quad   .Lsysc_done
1098         .quad   .Lio_tif
1099         .quad   .Lio_restore
1100         .quad   .Lio_done
1101         .quad   psw_idle
1102         .quad   .Lpsw_idle_end
1103         .quad   save_fpu_regs
1104         .quad   .Lsave_fpu_regs_end
1105         .quad   load_fpu_regs
1106         .quad   .Lload_fpu_regs_end
1107
1108 #if IS_ENABLED(CONFIG_KVM)
1109 .Lcleanup_table_sie:
1110         .quad   .Lsie_gmap
1111         .quad   .Lsie_done
1112
1113 .Lcleanup_sie:
1114         lg      %r9,__SF_EMPTY(%r15)            # get control block pointer
1115         ni      __SIE_PROG0C+3(%r9),0xfe        # no longer in SIE
1116         lctlg   %c1,%c1,__LC_USER_ASCE          # load primary asce
1117         larl    %r9,sie_exit                    # skip forward to sie_exit
1118         br      %r14
1119 #endif
1120
1121 .Lcleanup_system_call:
1122         # check if stpt has been executed
1123         clg     %r9,BASED(.Lcleanup_system_call_insn)
1124         jh      0f
1125         mvc     __LC_SYNC_ENTER_TIMER(8),__LC_ASYNC_ENTER_TIMER
1126         cghi    %r11,__LC_SAVE_AREA_ASYNC
1127         je      0f
1128         mvc     __LC_SYNC_ENTER_TIMER(8),__LC_MCCK_ENTER_TIMER
1129 0:      # check if stmg has been executed
1130         clg     %r9,BASED(.Lcleanup_system_call_insn+8)
1131         jh      0f
1132         mvc     __LC_SAVE_AREA_SYNC(64),0(%r11)
1133 0:      # check if base register setup + TIF bit load has been done
1134         clg     %r9,BASED(.Lcleanup_system_call_insn+16)
1135         jhe     0f
1136         # set up saved register r12 task struct pointer
1137         stg     %r12,32(%r11)
1138         # set up saved register r13 __TASK_thread offset
1139         mvc     40(8,%r11),BASED(.Lcleanup_system_call_const)
1140 0:      # check if the user time update has been done
1141         clg     %r9,BASED(.Lcleanup_system_call_insn+24)
1142         jh      0f
1143         lg      %r15,__LC_EXIT_TIMER
1144         slg     %r15,__LC_SYNC_ENTER_TIMER
1145         alg     %r15,__LC_USER_TIMER
1146         stg     %r15,__LC_USER_TIMER
1147 0:      # check if the system time update has been done
1148         clg     %r9,BASED(.Lcleanup_system_call_insn+32)
1149         jh      0f
1150         lg      %r15,__LC_LAST_UPDATE_TIMER
1151         slg     %r15,__LC_EXIT_TIMER
1152         alg     %r15,__LC_SYSTEM_TIMER
1153         stg     %r15,__LC_SYSTEM_TIMER
1154 0:      # update accounting time stamp
1155         mvc     __LC_LAST_UPDATE_TIMER(8),__LC_SYNC_ENTER_TIMER
1156         # set up saved register r11
1157         lg      %r15,__LC_KERNEL_STACK
1158         la      %r9,STACK_FRAME_OVERHEAD(%r15)
1159         stg     %r9,24(%r11)            # r11 pt_regs pointer
1160         # fill pt_regs
1161         mvc     __PT_R8(64,%r9),__LC_SAVE_AREA_SYNC
1162         stmg    %r0,%r7,__PT_R0(%r9)
1163         mvc     __PT_PSW(16,%r9),__LC_SVC_OLD_PSW
1164         mvc     __PT_INT_CODE(4,%r9),__LC_SVC_ILC
1165         xc      __PT_FLAGS(8,%r9),__PT_FLAGS(%r9)
1166         mvi     __PT_FLAGS+7(%r9),_PIF_SYSCALL
1167         # setup saved register r15
1168         stg     %r15,56(%r11)           # r15 stack pointer
1169         # set new psw address and exit
1170         larl    %r9,.Lsysc_do_svc
1171         br      %r14
1172 .Lcleanup_system_call_insn:
1173         .quad   system_call
1174         .quad   .Lsysc_stmg
1175         .quad   .Lsysc_per
1176         .quad   .Lsysc_vtime+36
1177         .quad   .Lsysc_vtime+42
1178 .Lcleanup_system_call_const:
1179         .quad   __TASK_thread
1180
1181 .Lcleanup_sysc_tif:
1182         larl    %r9,.Lsysc_tif
1183         br      %r14
1184
1185 .Lcleanup_sysc_restore:
1186         # check if stpt has been executed
1187         clg     %r9,BASED(.Lcleanup_sysc_restore_insn)
1188         jh      0f
1189         mvc     __LC_EXIT_TIMER(8),__LC_ASYNC_ENTER_TIMER
1190         cghi    %r11,__LC_SAVE_AREA_ASYNC
1191         je      0f
1192         mvc     __LC_EXIT_TIMER(8),__LC_MCCK_ENTER_TIMER
1193 0:      clg     %r9,BASED(.Lcleanup_sysc_restore_insn+8)
1194         je      1f
1195         lg      %r9,24(%r11)            # get saved pointer to pt_regs
1196         mvc     __LC_RETURN_PSW(16),__PT_PSW(%r9)
1197         mvc     0(64,%r11),__PT_R8(%r9)
1198         lmg     %r0,%r7,__PT_R0(%r9)
1199 1:      lmg     %r8,%r9,__LC_RETURN_PSW
1200         br      %r14
1201 .Lcleanup_sysc_restore_insn:
1202         .quad   .Lsysc_exit_timer
1203         .quad   .Lsysc_done - 4
1204
1205 .Lcleanup_io_tif:
1206         larl    %r9,.Lio_tif
1207         br      %r14
1208
1209 .Lcleanup_io_restore:
1210         # check if stpt has been executed
1211         clg     %r9,BASED(.Lcleanup_io_restore_insn)
1212         jh      0f
1213         mvc     __LC_EXIT_TIMER(8),__LC_MCCK_ENTER_TIMER
1214 0:      clg     %r9,BASED(.Lcleanup_io_restore_insn+8)
1215         je      1f
1216         lg      %r9,24(%r11)            # get saved r11 pointer to pt_regs
1217         mvc     __LC_RETURN_PSW(16),__PT_PSW(%r9)
1218         mvc     0(64,%r11),__PT_R8(%r9)
1219         lmg     %r0,%r7,__PT_R0(%r9)
1220 1:      lmg     %r8,%r9,__LC_RETURN_PSW
1221         br      %r14
1222 .Lcleanup_io_restore_insn:
1223         .quad   .Lio_exit_timer
1224         .quad   .Lio_done - 4
1225
1226 .Lcleanup_idle:
1227         ni      __LC_CPU_FLAGS+7,255-_CIF_ENABLED_WAIT
1228         # copy interrupt clock & cpu timer
1229         mvc     __CLOCK_IDLE_EXIT(8,%r2),__LC_INT_CLOCK
1230         mvc     __TIMER_IDLE_EXIT(8,%r2),__LC_ASYNC_ENTER_TIMER
1231         cghi    %r11,__LC_SAVE_AREA_ASYNC
1232         je      0f
1233         mvc     __CLOCK_IDLE_EXIT(8,%r2),__LC_MCCK_CLOCK
1234         mvc     __TIMER_IDLE_EXIT(8,%r2),__LC_MCCK_ENTER_TIMER
1235 0:      # check if stck & stpt have been executed
1236         clg     %r9,BASED(.Lcleanup_idle_insn)
1237         jhe     1f
1238         mvc     __CLOCK_IDLE_ENTER(8,%r2),__CLOCK_IDLE_EXIT(%r2)
1239         mvc     __TIMER_IDLE_ENTER(8,%r2),__TIMER_IDLE_EXIT(%r2)
1240 1:      # calculate idle cycles
1241 #ifdef CONFIG_SMP
1242         clg     %r9,BASED(.Lcleanup_idle_insn)
1243         jl      3f
1244         larl    %r1,smp_cpu_mtid
1245         llgf    %r1,0(%r1)
1246         ltgr    %r1,%r1
1247         jz      3f
1248         .insn   rsy,0xeb0000000017,%r1,5,__SF_EMPTY+80(%r15)
1249         larl    %r3,mt_cycles
1250         ag      %r3,__LC_PERCPU_OFFSET
1251         la      %r4,__SF_EMPTY+16(%r15)
1252 2:      lg      %r0,0(%r3)
1253         slg     %r0,0(%r4)
1254         alg     %r0,64(%r4)
1255         stg     %r0,0(%r3)
1256         la      %r3,8(%r3)
1257         la      %r4,8(%r4)
1258         brct    %r1,2b
1259 #endif
1260 3:      # account system time going idle
1261         lg      %r9,__LC_STEAL_TIMER
1262         alg     %r9,__CLOCK_IDLE_ENTER(%r2)
1263         slg     %r9,__LC_LAST_UPDATE_CLOCK
1264         stg     %r9,__LC_STEAL_TIMER
1265         mvc     __LC_LAST_UPDATE_CLOCK(8),__CLOCK_IDLE_EXIT(%r2)
1266         lg      %r9,__LC_SYSTEM_TIMER
1267         alg     %r9,__LC_LAST_UPDATE_TIMER
1268         slg     %r9,__TIMER_IDLE_ENTER(%r2)
1269         stg     %r9,__LC_SYSTEM_TIMER
1270         mvc     __LC_LAST_UPDATE_TIMER(8),__TIMER_IDLE_EXIT(%r2)
1271         # prepare return psw
1272         nihh    %r8,0xfcfd              # clear irq & wait state bits
1273         lg      %r9,48(%r11)            # return from psw_idle
1274         br      %r14
1275 .Lcleanup_idle_insn:
1276         .quad   .Lpsw_idle_lpsw
1277
1278 .Lcleanup_save_fpu_regs:
1279         larl    %r9,save_fpu_regs
1280         br      %r14
1281
1282 .Lcleanup_load_fpu_regs:
1283         larl    %r9,load_fpu_regs
1284         br      %r14
1285
1286 /*
1287  * Integer constants
1288  */
1289         .align  8
1290 .Lcritical_start:
1291         .quad   .L__critical_start
1292 .Lcritical_length:
1293         .quad   .L__critical_end - .L__critical_start
1294 #if IS_ENABLED(CONFIG_KVM)
1295 .Lsie_critical_start:
1296         .quad   .Lsie_gmap
1297 .Lsie_critical_length:
1298         .quad   .Lsie_done - .Lsie_gmap
1299 #endif
1300
1301         .section .rodata, "a"
1302 #define SYSCALL(esame,emu)      .long esame
1303         .globl  sys_call_table
1304 sys_call_table:
1305 #include "syscalls.S"
1306 #undef SYSCALL
1307
1308 #ifdef CONFIG_COMPAT
1309
1310 #define SYSCALL(esame,emu)      .long emu
1311         .globl  sys_call_table_emu
1312 sys_call_table_emu:
1313 #include "syscalls.S"
1314 #undef SYSCALL
1315 #endif