arch/s390/kernel/traps.c

   1 /*
   2  *  arch/s390/kernel/traps.c
   3  *
   4  *  S390 version
   5  *    Copyright (C) 1999,2000 IBM Deutschland Entwicklung GmbH, IBM Corporation
   6  *    Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
   7  *               Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com),
   8  *
   9  *  Derived from "arch/i386/kernel/traps.c"
  10  *    Copyright (C) 1991, 1992 Linus Torvalds
  11  */
  12
  13 /*
  14  * 'Traps.c' handles hardware traps and faults after we have saved some
  15  * state in 'asm.s'.
  16  */
  17 #include <linux/config.h>
  18 #include <linux/sched.h>
  19 #include <linux/kernel.h>
  20 #include <linux/string.h>
  21 #include <linux/errno.h>
  22 #include <linux/ptrace.h>
  23 #include <linux/timer.h>
  24 #include <linux/mm.h>
  25 #include <linux/smp.h>
  26 #include <linux/smp_lock.h>
  27 #include <linux/init.h>
  28 #include <linux/delay.h>
  29 #include <linux/module.h>
  30 #include <linux/kallsyms.h>
  31
  32 #include <asm/system.h>
  33 #include <asm/uaccess.h>
  34 #include <asm/io.h>
  35 #include <asm/atomic.h>
  36 #include <asm/mathemu.h>
  37 #include <asm/cpcmd.h>
  38 #include <asm/s390_ext.h>
  39 #include <asm/lowcore.h>
  40
  41 /* Called from entry.S only */
  42 extern void handle_per_exception(struct pt_regs *regs);
  43
  44 typedef void pgm_check_handler_t(struct pt_regs *, long);
  45 pgm_check_handler_t *pgm_check_table[128];
  46
  47 #ifdef CONFIG_SYSCTL
  48 #ifdef CONFIG_PROCESS_DEBUG
  49 int sysctl_userprocess_debug = 1;
  50 #else
  51 int sysctl_userprocess_debug = 0;
  52 #endif
  53 #endif
  54
  55 extern pgm_check_handler_t do_protection_exception;
  56 extern pgm_check_handler_t do_segment_exception;
  57 extern pgm_check_handler_t do_region_exception;
  58 extern pgm_check_handler_t do_page_exception;
  59 extern pgm_check_handler_t do_pseudo_page_fault;
  60 #ifdef CONFIG_PFAULT
  61 extern int pfault_init(void);
  62 extern void pfault_fini(void);
  63 extern void pfault_interrupt(struct pt_regs *regs, __u16 error_code);
  64 static ext_int_info_t ext_int_pfault;
  65 #endif
  66
  67 #define stack_pointer ({ void **sp; asm("la %0,0(15)" : "=&d" (sp)); sp; })
  68
  69 #ifndef CONFIG_ARCH_S390X
  70 #define RET_ADDR 56
  71 #define FOURLONG "%08lx %08lx %08lx %08lx\n"
  72 static int kstack_depth_to_print = 12;
  73
  74 #else /* CONFIG_ARCH_S390X */
  75 #define RET_ADDR 112
  76 #define FOURLONG "%016lx %016lx %016lx %016lx\n"
  77 static int kstack_depth_to_print = 20;
  78
  79 #endif /* CONFIG_ARCH_S390X */
  80
  81 void show_trace(struct task_struct *task, unsigned long * stack)
  82 {
  83         unsigned long backchain, low_addr, high_addr, ret_addr;
  84
  85         if (!stack)
  86                 stack = *stack_pointer;
  87
  88         printk("Call Trace:\n");
  89         low_addr = ((unsigned long) stack) & PSW_ADDR_INSN;
  90         high_addr = (low_addr & (-THREAD_SIZE)) + THREAD_SIZE;
  91         /* Skip the first frame (biased stack) */
  92         backchain = *((unsigned long *) low_addr) & PSW_ADDR_INSN;
  93         /* Print up to 8 lines */
  94         while  (backchain > low_addr && backchain <= high_addr) {
  95                 ret_addr = *((unsigned long *) (backchain+RET_ADDR)) & PSW_ADDR_INSN;
  96                 printk(" [<%016lx>] ", ret_addr);
  97                 print_symbol("%s\n", ret_addr);
  98                 low_addr = backchain;
  99                 backchain = *((unsigned long *) backchain) & PSW_ADDR_INSN;
 100         }
 101         printk("\n");
 102 }
 103
 104 void show_trace_task(struct task_struct *tsk)
 105 {
 106         /*
 107          * We can't print the backtrace of a running process. It is
 108          * unreliable at best and can cause kernel oopses.
 109          */
 110         if (tsk->state == TASK_RUNNING)
 111                 return;
 112         show_trace(tsk, (unsigned long *) tsk->thread.ksp);
 113 }
 114
 115 void show_stack(struct task_struct *task, unsigned long *sp)
 116 {
 117         unsigned long *stack;
 118         int i;
 119
 120         // debugging aid: "show_stack(NULL);" prints the
 121         // back trace for this cpu.
 122
 123         if(sp == NULL)
 124                 sp = *stack_pointer;
 125
 126         stack = sp;
 127         for (i = 0; i < kstack_depth_to_print; i++) {
 128                 if (((addr_t) stack & (THREAD_SIZE-1)) == 0)
 129                         break;
 130                 if (i && ((i * sizeof (long) % 32) == 0))
 131                         printk("\n       ");
 132                 printk("%p ", (void *)*stack++);
 133         }
 134         printk("\n");
 135         show_trace(task, sp);
 136 }
 137
 138 /*
 139  * The architecture-independent dump_stack generator
 140  */
 141 void dump_stack(void)
 142 {
 143         show_stack(current, 0);
 144 }
 145
 146 void show_registers(struct pt_regs *regs)
 147 {
 148         mm_segment_t old_fs;
 149         char *mode;
 150         int i;
 151
 152         mode = (regs->psw.mask & PSW_MASK_PSTATE) ? "User" : "Krnl";
 153         printk("%s PSW : %p %p\n",
 154                mode, (void *) regs->psw.mask,
 155                (void *) regs->psw.addr);
 156         printk("%s GPRS: " FOURLONG, mode,
 157                regs->gprs[0], regs->gprs[1], regs->gprs[2], regs->gprs[3]);
 158         printk("           " FOURLONG,
 159                regs->gprs[4], regs->gprs[5], regs->gprs[6], regs->gprs[7]);
 160         printk("           " FOURLONG,
 161                regs->gprs[8], regs->gprs[9], regs->gprs[10], regs->gprs[11]);
 162         printk("           " FOURLONG,
 163                regs->gprs[12], regs->gprs[13], regs->gprs[14], regs->gprs[15]);
 164
 165         printk("%s ACRS: %08x %08x %08x %08x\n", mode,
 166                regs->acrs[0], regs->acrs[1], regs->acrs[2], regs->acrs[3]);
 167         printk("           %08x %08x %08x %08x\n",
 168                regs->acrs[4], regs->acrs[5], regs->acrs[6], regs->acrs[7]);
 169         printk("           %08x %08x %08x %08x\n",
 170                regs->acrs[8], regs->acrs[9], regs->acrs[10], regs->acrs[11]);
 171         printk("           %08x %08x %08x %08x\n",
 172                regs->acrs[12], regs->acrs[13], regs->acrs[14], regs->acrs[15]);
 173
 174         /*
 175          * Print the first 20 byte of the instruction stream at the
 176          * time of the fault.
 177          */
 178         old_fs = get_fs();
 179         if (regs->psw.mask & PSW_MASK_PSTATE)
 180                 set_fs(USER_DS);
 181         else
 182                 set_fs(KERNEL_DS);
 183         printk("%s Code: ", mode);
 184         for (i = 0; i < 20; i++) {
 185                 unsigned char c;
 186                 if (__get_user(c, (char *)(regs->psw.addr + i))) {
 187                         printk(" Bad PSW.");
 188                         break;
 189                 }
 190                 printk("%02x ", c);
 191         }
 192         set_fs(old_fs);
 193
 194         printk("\n");
 195 }
 196
 197 /* This is called from fs/proc/array.c */
 198 char *task_show_regs(struct task_struct *task, char *buffer)
 199 {
 200         struct pt_regs *regs;
 201
 202         regs = __KSTK_PTREGS(task);
 203         buffer += sprintf(buffer, "task: %p, ksp: %p\n",
 204                        task, (void *)task->thread.ksp);
 205         buffer += sprintf(buffer, "User PSW : %p %p\n",
 206                        (void *) regs->psw.mask, (void *)regs->psw.addr);
 207
 208         buffer += sprintf(buffer, "User GPRS: " FOURLONG,
 209                           regs->gprs[0], regs->gprs[1],
 210                           regs->gprs[2], regs->gprs[3]);
 211         buffer += sprintf(buffer, "           " FOURLONG,
 212                           regs->gprs[4], regs->gprs[5],
 213                           regs->gprs[6], regs->gprs[7]);
 214         buffer += sprintf(buffer, "           " FOURLONG,
 215                           regs->gprs[8], regs->gprs[9],
 216                           regs->gprs[10], regs->gprs[11]);
 217         buffer += sprintf(buffer, "           " FOURLONG,
 218                           regs->gprs[12], regs->gprs[13],
 219                           regs->gprs[14], regs->gprs[15]);
 220         buffer += sprintf(buffer, "User ACRS: %08x %08x %08x %08x\n",
 221                           regs->acrs[0], regs->acrs[1],
 222                           regs->acrs[2], regs->acrs[3]);
 223         buffer += sprintf(buffer, "           %08x %08x %08x %08x\n",
 224                           regs->acrs[4], regs->acrs[5],
 225                           regs->acrs[6], regs->acrs[7]);
 226         buffer += sprintf(buffer, "           %08x %08x %08x %08x\n",
 227                           regs->acrs[8], regs->acrs[9],
 228                           regs->acrs[10], regs->acrs[11]);
 229         buffer += sprintf(buffer, "           %08x %08x %08x %08x\n",
 230                           regs->acrs[12], regs->acrs[13],
 231                           regs->acrs[14], regs->acrs[15]);
 232         return buffer;
 233 }
 234
 235 spinlock_t die_lock = SPIN_LOCK_UNLOCKED;
 236
 237 void die(const char * str, struct pt_regs * regs, long err)
 238 {
 239         static int die_counter;
 240         console_verbose();
 241         spin_lock_irq(&die_lock);
 242         bust_spinlocks(1);
 243         printk("%s: %04lx [#%d]\n", str, err & 0xffff, ++die_counter);
 244         show_regs(regs);
 245         bust_spinlocks(0);
 246         spin_unlock_irq(&die_lock);
 247         do_exit(SIGSEGV);
 248 }
 249
 250 static void inline do_trap(long interruption_code, int signr, char *str,
 251                            struct pt_regs *regs, siginfo_t *info)
 252 {
 253         /*
 254          * We got all needed information from the lowcore and can
 255          * now safely switch on interrupts.
 256          */
 257         if (regs->psw.mask & PSW_MASK_PSTATE)
 258                 local_irq_enable();
 259
 260         if (regs->psw.mask & PSW_MASK_PSTATE) {
 261                 struct task_struct *tsk = current;
 262
 263                 tsk->thread.trap_no = interruption_code & 0xffff;
 264                 if (info)
 265                         force_sig_info(signr, info, tsk);
 266                 else
 267                         force_sig(signr, tsk);
 268 #ifndef CONFIG_SYSCTL
 269 #ifdef CONFIG_PROCESS_DEBUG
 270                 printk("User process fault: interruption code 0x%lX\n",
 271                        interruption_code);
 272                 show_regs(regs);
 273 #endif
 274 #else
 275                 if (sysctl_userprocess_debug) {
 276                         printk("User process fault: interruption code 0x%lX\n",
 277                                interruption_code);
 278                         show_regs(regs);
 279                 }
 280 #endif
 281         } else {
 282                 const struct exception_table_entry *fixup;
 283                 fixup = search_exception_tables(regs->psw.addr & PSW_ADDR_INSN);
 284                 if (fixup)
 285                         regs->psw.addr = fixup->fixup | PSW_ADDR_AMODE;
 286                 else
 287                         die(str, regs, interruption_code);
 288         }
 289 }
 290
 291 static inline void *get_check_address(struct pt_regs *regs)
 292 {
 293         return (void *)((regs->psw.addr-S390_lowcore.pgm_ilc) & PSW_ADDR_INSN);
 294 }
 295
 296 static int do_debugger_trap(struct pt_regs *regs)
 297 {
 298         if ((regs->psw.mask & PSW_MASK_PSTATE) &&
 299             (current->ptrace & PT_PTRACED)) {
 300                 force_sig(SIGTRAP,current);
 301                 return 0;
 302         }
 303         return 1;
 304 }
 305
 306 #define DO_ERROR(signr, str, name) \
 307 asmlinkage void name(struct pt_regs * regs, long interruption_code) \
 308 { \
 309         do_trap(interruption_code, signr, str, regs, NULL); \
 310 }
 311
 312 #define DO_ERROR_INFO(signr, str, name, sicode, siaddr) \
 313 asmlinkage void name(struct pt_regs * regs, long interruption_code) \
 314 { \
 315         siginfo_t info; \
 316         info.si_signo = signr; \
 317         info.si_errno = 0; \
 318         info.si_code = sicode; \
 319         info.si_addr = (void *)siaddr; \
 320         do_trap(interruption_code, signr, str, regs, &info); \
 321 }
 322
 323 DO_ERROR(SIGSEGV, "Unknown program exception", default_trap_handler)
 324
 325 DO_ERROR_INFO(SIGBUS, "addressing exception", addressing_exception,
 326               BUS_ADRERR, get_check_address(regs))
 327 DO_ERROR_INFO(SIGILL,  "execute exception", execute_exception,
 328               ILL_ILLOPN, get_check_address(regs))
 329 DO_ERROR_INFO(SIGFPE,  "fixpoint divide exception", divide_exception,
 330               FPE_INTDIV, get_check_address(regs))
 331 DO_ERROR_INFO(SIGILL,  "operand exception", operand_exception,
 332               ILL_ILLOPN, get_check_address(regs))
 333 DO_ERROR_INFO(SIGILL,  "privileged operation", privileged_op,
 334               ILL_PRVOPC, get_check_address(regs))
 335 DO_ERROR_INFO(SIGILL,  "special operation exception", special_op_exception,
 336               ILL_ILLOPN, get_check_address(regs))
 337 DO_ERROR_INFO(SIGILL,  "translation exception", translation_exception,
 338               ILL_ILLOPN, get_check_address(regs))
 339
 340 static inline void
 341 do_fp_trap(struct pt_regs *regs, void *location,
 342            int fpc, long interruption_code)
 343 {
 344         siginfo_t si;
 345
 346         si.si_signo = SIGFPE;
 347         si.si_errno = 0;
 348         si.si_addr = location;
 349         si.si_code = 0;
 350         /* FPC[2] is Data Exception Code */
 351         if ((fpc & 0x00000300) == 0) {
 352                 /* bits 6 and 7 of DXC are 0 iff IEEE exception */
 353                 if (fpc & 0x8000) /* invalid fp operation */
 354                         si.si_code = FPE_FLTINV;
 355                 else if (fpc & 0x4000) /* div by 0 */
 356                         si.si_code = FPE_FLTDIV;
 357                 else if (fpc & 0x2000) /* overflow */
 358                         si.si_code = FPE_FLTOVF;
 359                 else if (fpc & 0x1000) /* underflow */
 360                         si.si_code = FPE_FLTUND;
 361                 else if (fpc & 0x0800) /* inexact */
 362                         si.si_code = FPE_FLTRES;
 363         }
 364         current->thread.ieee_instruction_pointer = (addr_t) location;
 365         do_trap(interruption_code, SIGFPE,
 366                 "floating point exception", regs, &si);
 367 }
 368
 369 asmlinkage void illegal_op(struct pt_regs * regs, long interruption_code)
 370 {
 371         __u8 opcode[6];
 372         __u16 *location;
 373         int signal = 0;
 374
 375         location = (__u16 *) get_check_address(regs);
 376
 377         /*
 378          * We got all needed information from the lowcore and can
 379          * now safely switch on interrupts.
 380          */
 381         if (regs->psw.mask & PSW_MASK_PSTATE)
 382                 local_irq_enable();
 383
 384         if (regs->psw.mask & PSW_MASK_PSTATE)
 385                 get_user(*((__u16 *) opcode), location);
 386         else
 387                 *((__u16 *)opcode)=*((__u16 *)location);
 388         if (*((__u16 *)opcode)==S390_BREAKPOINT_U16)
 389         {
 390                 if(do_debugger_trap(regs))
 391                         signal = SIGILL;
 392         }
 393 #ifdef CONFIG_MATHEMU
 394         else if (regs->psw.mask & PSW_MASK_PSTATE)
 395         {
 396                 if (opcode[0] == 0xb3) {
 397                         get_user(*((__u16 *) (opcode+2)), location+1);
 398                         signal = math_emu_b3(opcode, regs);
 399                 } else if (opcode[0] == 0xed) {
 400                         get_user(*((__u32 *) (opcode+2)),
 401                                  (__u32 *)(location+1));
 402                         signal = math_emu_ed(opcode, regs);
 403                 } else if (*((__u16 *) opcode) == 0xb299) {
 404                         get_user(*((__u16 *) (opcode+2)), location+1);
 405                         signal = math_emu_srnm(opcode, regs);
 406                 } else if (*((__u16 *) opcode) == 0xb29c) {
 407                         get_user(*((__u16 *) (opcode+2)), location+1);
 408                         signal = math_emu_stfpc(opcode, regs);
 409                 } else if (*((__u16 *) opcode) == 0xb29d) {
 410                         get_user(*((__u16 *) (opcode+2)), location+1);
 411                         signal = math_emu_lfpc(opcode, regs);
 412                 } else
 413                         signal = SIGILL;
 414         }
 415 #endif
 416         else
 417                 signal = SIGILL;
 418         if (signal == SIGFPE)
 419                 do_fp_trap(regs, location,
 420                            current->thread.fp_regs.fpc, interruption_code);
 421         else if (signal)
 422                 do_trap(interruption_code, signal,
 423                         "illegal operation", regs, NULL);
 424 }
 425
 426
 427 #ifdef CONFIG_MATHEMU
 428 asmlinkage void
 429 specification_exception(struct pt_regs * regs, long interruption_code)
 430 {
 431         __u8 opcode[6];
 432         __u16 *location = NULL;
 433         int signal = 0;
 434
 435         location = (__u16 *) get_check_address(regs);
 436
 437         /*
 438          * We got all needed information from the lowcore and can
 439          * now safely switch on interrupts.
 440          */
 441         if (regs->psw.mask & PSW_MASK_PSTATE)
 442                 local_irq_enable();
 443
 444         if (regs->psw.mask & PSW_MASK_PSTATE) {
 445                 get_user(*((__u16 *) opcode), location);
 446                 switch (opcode[0]) {
 447                 case 0x28: /* LDR Rx,Ry   */
 448                         signal = math_emu_ldr(opcode);
 449                         break;
 450                 case 0x38: /* LER Rx,Ry   */
 451                         signal = math_emu_ler(opcode);
 452                         break;
 453                 case 0x60: /* STD R,D(X,B) */
 454                         get_user(*((__u16 *) (opcode+2)), location+1);
 455                         signal = math_emu_std(opcode, regs);
 456                         break;
 457                 case 0x68: /* LD R,D(X,B) */
 458                         get_user(*((__u16 *) (opcode+2)), location+1);
 459                         signal = math_emu_ld(opcode, regs);
 460                         break;
 461                 case 0x70: /* STE R,D(X,B) */
 462                         get_user(*((__u16 *) (opcode+2)), location+1);
 463                         signal = math_emu_ste(opcode, regs);
 464                         break;
 465                 case 0x78: /* LE R,D(X,B) */
 466                         get_user(*((__u16 *) (opcode+2)), location+1);
 467                         signal = math_emu_le(opcode, regs);
 468                         break;
 469                 default:
 470                         signal = SIGILL;
 471                         break;
 472                 }
 473         } else
 474                 signal = SIGILL;
 475         if (signal == SIGFPE)
 476                 do_fp_trap(regs, location,
 477                            current->thread.fp_regs.fpc, interruption_code);
 478         else if (signal) {
 479                 siginfo_t info;
 480                 info.si_signo = signal;
 481                 info.si_errno = 0;
 482                 info.si_code = ILL_ILLOPN;
 483                 info.si_addr = location;
 484                 do_trap(interruption_code, signal,
 485                         "specification exception", regs, &info);
 486         }
 487 }
 488 #else
 489 DO_ERROR_INFO(SIGILL, "specification exception", specification_exception,
 490               ILL_ILLOPN, get_check_address(regs));
 491 #endif
 492
 493 asmlinkage void data_exception(struct pt_regs * regs, long interruption_code)
 494 {
 495         __u16 *location;
 496         int signal = 0;
 497
 498         location = (__u16 *) get_check_address(regs);
 499
 500         /*
 501          * We got all needed information from the lowcore and can
 502          * now safely switch on interrupts.
 503          */
 504         if (regs->psw.mask & PSW_MASK_PSTATE)
 505                 local_irq_enable();
 506
 507         if (MACHINE_HAS_IEEE)
 508                 __asm__ volatile ("stfpc %0\n\t"
 509                                   : "=m" (current->thread.fp_regs.fpc));
 510
 511 #ifdef CONFIG_MATHEMU
 512         else if (regs->psw.mask & PSW_MASK_PSTATE) {
 513                 __u8 opcode[6];
 514                 get_user(*((__u16 *) opcode), location);
 515                 switch (opcode[0]) {
 516                 case 0x28: /* LDR Rx,Ry   */
 517                         signal = math_emu_ldr(opcode);
 518                         break;
 519                 case 0x38: /* LER Rx,Ry   */
 520                         signal = math_emu_ler(opcode);
 521                         break;
 522                 case 0x60: /* STD R,D(X,B) */
 523                         get_user(*((__u16 *) (opcode+2)), location+1);
 524                         signal = math_emu_std(opcode, regs);
 525                         break;
 526                 case 0x68: /* LD R,D(X,B) */
 527                         get_user(*((__u16 *) (opcode+2)), location+1);
 528                         signal = math_emu_ld(opcode, regs);
 529                         break;
 530                 case 0x70: /* STE R,D(X,B) */
 531                         get_user(*((__u16 *) (opcode+2)), location+1);
 532                         signal = math_emu_ste(opcode, regs);
 533                         break;
 534                 case 0x78: /* LE R,D(X,B) */
 535                         get_user(*((__u16 *) (opcode+2)), location+1);
 536                         signal = math_emu_le(opcode, regs);
 537                         break;
 538                 case 0xb3:
 539                         get_user(*((__u16 *) (opcode+2)), location+1);
 540                         signal = math_emu_b3(opcode, regs);
 541                         break;
 542                 case 0xed:
 543                         get_user(*((__u32 *) (opcode+2)),
 544                                  (__u32 *)(location+1));
 545                         signal = math_emu_ed(opcode, regs);
 546                         break;
 547                 case 0xb2:
 548                         if (opcode[1] == 0x99) {
 549                                 get_user(*((__u16 *) (opcode+2)), location+1);
 550                                 signal = math_emu_srnm(opcode, regs);
 551                         } else if (opcode[1] == 0x9c) {
 552                                 get_user(*((__u16 *) (opcode+2)), location+1);
 553                                 signal = math_emu_stfpc(opcode, regs);
 554                         } else if (opcode[1] == 0x9d) {
 555                                 get_user(*((__u16 *) (opcode+2)), location+1);
 556                                 signal = math_emu_lfpc(opcode, regs);
 557                         } else
 558                                 signal = SIGILL;
 559                         break;
 560                 default:
 561                         signal = SIGILL;
 562                         break;
 563                 }
 564         }
 565 #endif
 566         if (current->thread.fp_regs.fpc & FPC_DXC_MASK)
 567                 signal = SIGFPE;
 568         else
 569                 signal = SIGILL;
 570         if (signal == SIGFPE)
 571                 do_fp_trap(regs, location,
 572                            current->thread.fp_regs.fpc, interruption_code);
 573         else if (signal) {
 574                 siginfo_t info;
 575                 info.si_signo = signal;
 576                 info.si_errno = 0;
 577                 info.si_code = ILL_ILLOPN;
 578                 info.si_addr = location;
 579                 do_trap(interruption_code, signal,
 580                         "data exception", regs, &info);
 581         }
 582 }
 583
 584
 585
 586 /* init is done in lowcore.S and head.S */
 587
 588 void __init trap_init(void)
 589 {
 590         int i;
 591
 592         for (i = 0; i < 128; i++)
 593           pgm_check_table[i] = &default_trap_handler;
 594         pgm_check_table[1] = &illegal_op;
 595         pgm_check_table[2] = &privileged_op;
 596         pgm_check_table[3] = &execute_exception;
 597         pgm_check_table[4] = &do_protection_exception;
 598         pgm_check_table[5] = &addressing_exception;
 599         pgm_check_table[6] = &specification_exception;
 600         pgm_check_table[7] = &data_exception;
 601         pgm_check_table[9] = &divide_exception;
 602         pgm_check_table[0x10] = &do_segment_exception;
 603         pgm_check_table[0x11] = &do_page_exception;
 604         pgm_check_table[0x10] = &do_segment_exception;
 605         pgm_check_table[0x11] = &do_page_exception;
 606         pgm_check_table[0x12] = &translation_exception;
 607         pgm_check_table[0x13] = &special_op_exception;
 608 #ifndef CONFIG_ARCH_S390X
 609         pgm_check_table[0x14] = &do_pseudo_page_fault;
 610 #else /* CONFIG_ARCH_S390X */
 611         pgm_check_table[0x38] = &addressing_exception;
 612         pgm_check_table[0x3B] = &do_region_exception;
 613 #endif /* CONFIG_ARCH_S390X */
 614         pgm_check_table[0x15] = &operand_exception;
 615         pgm_check_table[0x1C] = &privileged_op;
 616         if (MACHINE_IS_VM) {
 617                 /*
 618                  * First try to get pfault pseudo page faults going.
 619                  * If this isn't available turn on pagex page faults.
 620                  */
 621 #ifdef CONFIG_PFAULT
 622                 /* request the 0x2603 external interrupt */
 623                 if (register_early_external_interrupt(0x2603, pfault_interrupt,
 624                                                       &ext_int_pfault) != 0)
 625                         panic("Couldn't request external interrupt 0x2603");
 626
 627                 if (pfault_init() == 0)
 628                         return;
 629
 630                 /* Tough luck, no pfault. */
 631                 unregister_early_external_interrupt(0x2603, pfault_interrupt,
 632                                                     &ext_int_pfault);
 633 #endif
 634 #ifndef CONFIG_ARCH_S390X
 635                 cpcmd("SET PAGEX ON", NULL, 0);
 636 #endif
 637         }
 638 }
 639
 640
 641 void handle_per_exception(struct pt_regs *regs)
 642 {
 643         if (regs->psw.mask & PSW_MASK_PSTATE) {
 644                 per_struct *per_info=&current->thread.per_info;
 645                 per_info->lowcore.words.perc_atmid=S390_lowcore.per_perc_atmid;
 646                 per_info->lowcore.words.address=S390_lowcore.per_address;
 647                 per_info->lowcore.words.access_id=S390_lowcore.per_access_id;
 648         }
 649         if (do_debugger_trap(regs)) {
 650                 /* I've seen this possibly a task structure being reused ? */
 651                 printk("Spurious per exception detected\n");
 652                 printk("switching off per tracing for this task.\n");
 653                 show_regs(regs);
 654                 /* Hopefully switching off per tracing will help us survive */
 655                 regs->psw.mask &= ~PSW_MASK_PER;
 656         }
 657 }
 658