arch/s390/kernel/traps.c

   1 /*
   2  *  S390 version
   3  *    Copyright IBM Corp. 1999, 2000
   4  *    Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
   5  *               Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com),
   6  *
   7  *  Derived from "arch/i386/kernel/traps.c"
   8  *    Copyright (C) 1991, 1992 Linus Torvalds
   9  */
  10
  11 /*
  12  * 'Traps.c' handles hardware traps and faults after we have saved some
  13  * state in 'asm.s'.
  14  */
  15 #include <linux/sched.h>
  16 #include <linux/kernel.h>
  17 #include <linux/string.h>
  18 #include <linux/errno.h>
  19 #include <linux/ptrace.h>
  20 #include <linux/timer.h>
  21 #include <linux/mm.h>
  22 #include <linux/smp.h>
  23 #include <linux/init.h>
  24 #include <linux/interrupt.h>
  25 #include <linux/seq_file.h>
  26 #include <linux/delay.h>
  27 #include <linux/module.h>
  28 #include <linux/kdebug.h>
  29 #include <linux/kallsyms.h>
  30 #include <linux/reboot.h>
  31 #include <linux/kprobes.h>
  32 #include <linux/bug.h>
  33 #include <linux/utsname.h>
  34 #include <asm/uaccess.h>
  35 #include <asm/io.h>
  36 #include <linux/atomic.h>
  37 #include <asm/mathemu.h>
  38 #include <asm/cpcmd.h>
  39 #include <asm/lowcore.h>
  40 #include <asm/debug.h>
  41 #include <asm/ipl.h>
  42 #include "entry.h"
  43
  44 void (*pgm_check_table[128])(struct pt_regs *regs);
  45
  46 int show_unhandled_signals = 1;
  47
  48 #define stack_pointer ({ void **sp; asm("la %0,0(15)" : "=&d" (sp)); sp; })
  49
  50 #ifndef CONFIG_64BIT
  51 #define LONG "%08lx "
  52 #define FOURLONG "%08lx %08lx %08lx %08lx\n"
  53 static int kstack_depth_to_print = 12;
  54 #else /* CONFIG_64BIT */
  55 #define LONG "%016lx "
  56 #define FOURLONG "%016lx %016lx %016lx %016lx\n"
  57 static int kstack_depth_to_print = 20;
  58 #endif /* CONFIG_64BIT */
  59
  60 /*
  61  * For show_trace we have tree different stack to consider:
  62  *   - the panic stack which is used if the kernel stack has overflown
  63  *   - the asynchronous interrupt stack (cpu related)
  64  *   - the synchronous kernel stack (process related)
  65  * The stack trace can start at any of the three stack and can potentially
  66  * touch all of them. The order is: panic stack, async stack, sync stack.
  67  */
  68 static unsigned long
  69 __show_trace(unsigned long sp, unsigned long low, unsigned long high)
  70 {
  71         struct stack_frame *sf;
  72         struct pt_regs *regs;
  73
  74         while (1) {
  75                 sp = sp & PSW_ADDR_INSN;
  76                 if (sp < low || sp > high - sizeof(*sf))
  77                         return sp;
  78                 sf = (struct stack_frame *) sp;
  79                 printk("([<%016lx>] ", sf->gprs[8] & PSW_ADDR_INSN);
  80                 print_symbol("%s)\n", sf->gprs[8] & PSW_ADDR_INSN);
  81                 /* Follow the backchain. */
  82                 while (1) {
  83                         low = sp;
  84                         sp = sf->back_chain & PSW_ADDR_INSN;
  85                         if (!sp)
  86                                 break;
  87                         if (sp <= low || sp > high - sizeof(*sf))
  88                                 return sp;
  89                         sf = (struct stack_frame *) sp;
  90                         printk(" [<%016lx>] ", sf->gprs[8] & PSW_ADDR_INSN);
  91                         print_symbol("%s\n", sf->gprs[8] & PSW_ADDR_INSN);
  92                 }
  93                 /* Zero backchain detected, check for interrupt frame. */
  94                 sp = (unsigned long) (sf + 1);
  95                 if (sp <= low || sp > high - sizeof(*regs))
  96                         return sp;
  97                 regs = (struct pt_regs *) sp;
  98                 printk(" [<%016lx>] ", regs->psw.addr & PSW_ADDR_INSN);
  99                 print_symbol("%s\n", regs->psw.addr & PSW_ADDR_INSN);
 100                 low = sp;
 101                 sp = regs->gprs[15];
 102         }
 103 }
 104
 105 static void show_trace(struct task_struct *task, unsigned long *stack)
 106 {
 107         register unsigned long __r15 asm ("15");
 108         unsigned long sp;
 109
 110         sp = (unsigned long) stack;
 111         if (!sp)
 112                 sp = task ? task->thread.ksp : __r15;
 113         printk("Call Trace:\n");
 114 #ifdef CONFIG_CHECK_STACK
 115         sp = __show_trace(sp, S390_lowcore.panic_stack - 4096,
 116                           S390_lowcore.panic_stack);
 117 #endif
 118         sp = __show_trace(sp, S390_lowcore.async_stack - ASYNC_SIZE,
 119                           S390_lowcore.async_stack);
 120         if (task)
 121                 __show_trace(sp, (unsigned long) task_stack_page(task),
 122                              (unsigned long) task_stack_page(task) + THREAD_SIZE);
 123         else
 124                 __show_trace(sp, S390_lowcore.thread_info,
 125                              S390_lowcore.thread_info + THREAD_SIZE);
 126         if (!task)
 127                 task = current;
 128         debug_show_held_locks(task);
 129 }
 130
 131 void show_stack(struct task_struct *task, unsigned long *sp)
 132 {
 133         register unsigned long * __r15 asm ("15");
 134         unsigned long *stack;
 135         int i;
 136
 137         if (!sp)
 138                 stack = task ? (unsigned long *) task->thread.ksp : __r15;
 139         else
 140                 stack = sp;
 141
 142         for (i = 0; i < kstack_depth_to_print; i++) {
 143                 if (((addr_t) stack & (THREAD_SIZE-1)) == 0)
 144                         break;
 145                 if ((i * sizeof(long) % 32) == 0)
 146                         printk("%s       ", i == 0 ? "" : "\n");
 147                 printk(LONG, *stack++);
 148         }
 149         printk("\n");
 150         show_trace(task, sp);
 151 }
 152
 153 static void show_last_breaking_event(struct pt_regs *regs)
 154 {
 155 #ifdef CONFIG_64BIT
 156         printk("Last Breaking-Event-Address:\n");
 157         printk(" [<%016lx>] ", regs->args[0] & PSW_ADDR_INSN);
 158         print_symbol("%s\n", regs->args[0] & PSW_ADDR_INSN);
 159 #endif
 160 }
 161
 162 /*
 163  * The architecture-independent dump_stack generator
 164  */
 165 void dump_stack(void)
 166 {
 167         printk("CPU: %d %s %s %.*s\n",
 168                task_thread_info(current)->cpu, print_tainted(),
 169                init_utsname()->release,
 170                (int)strcspn(init_utsname()->version, " "),
 171                init_utsname()->version);
 172         printk("Process %s (pid: %d, task: %p, ksp: %p)\n",
 173                current->comm, current->pid, current,
 174                (void *) current->thread.ksp);
 175         show_stack(NULL, NULL);
 176 }
 177 EXPORT_SYMBOL(dump_stack);
 178
 179 static inline int mask_bits(struct pt_regs *regs, unsigned long bits)
 180 {
 181         return (regs->psw.mask & bits) / ((~bits + 1) & bits);
 182 }
 183
 184 void show_registers(struct pt_regs *regs)
 185 {
 186         char *mode;
 187
 188         mode = (regs->psw.mask & PSW_MASK_PSTATE) ? "User" : "Krnl";
 189         printk("%s PSW : %p %p",
 190                mode, (void *) regs->psw.mask,
 191                (void *) regs->psw.addr);
 192         print_symbol(" (%s)\n", regs->psw.addr & PSW_ADDR_INSN);
 193         printk("           R:%x T:%x IO:%x EX:%x Key:%x M:%x W:%x "
 194                "P:%x AS:%x CC:%x PM:%x", mask_bits(regs, PSW_MASK_PER),
 195                mask_bits(regs, PSW_MASK_DAT), mask_bits(regs, PSW_MASK_IO),
 196                mask_bits(regs, PSW_MASK_EXT), mask_bits(regs, PSW_MASK_KEY),
 197                mask_bits(regs, PSW_MASK_MCHECK), mask_bits(regs, PSW_MASK_WAIT),
 198                mask_bits(regs, PSW_MASK_PSTATE), mask_bits(regs, PSW_MASK_ASC),
 199                mask_bits(regs, PSW_MASK_CC), mask_bits(regs, PSW_MASK_PM));
 200 #ifdef CONFIG_64BIT
 201         printk(" EA:%x", mask_bits(regs, PSW_MASK_EA | PSW_MASK_BA));
 202 #endif
 203         printk("\n%s GPRS: " FOURLONG, mode,
 204                regs->gprs[0], regs->gprs[1], regs->gprs[2], regs->gprs[3]);
 205         printk("           " FOURLONG,
 206                regs->gprs[4], regs->gprs[5], regs->gprs[6], regs->gprs[7]);
 207         printk("           " FOURLONG,
 208                regs->gprs[8], regs->gprs[9], regs->gprs[10], regs->gprs[11]);
 209         printk("           " FOURLONG,
 210                regs->gprs[12], regs->gprs[13], regs->gprs[14], regs->gprs[15]);
 211
 212         show_code(regs);
 213 }
 214
 215 void show_regs(struct pt_regs *regs)
 216 {
 217         print_modules();
 218         printk("CPU: %d %s %s %.*s\n",
 219                task_thread_info(current)->cpu, print_tainted(),
 220                init_utsname()->release,
 221                (int)strcspn(init_utsname()->version, " "),
 222                init_utsname()->version);
 223         printk("Process %s (pid: %d, task: %p, ksp: %p)\n",
 224                current->comm, current->pid, current,
 225                (void *) current->thread.ksp);
 226         show_registers(regs);
 227         /* Show stack backtrace if pt_regs is from kernel mode */
 228         if (!(regs->psw.mask & PSW_MASK_PSTATE))
 229                 show_trace(NULL, (unsigned long *) regs->gprs[15]);
 230         show_last_breaking_event(regs);
 231 }
 232
 233 static DEFINE_SPINLOCK(die_lock);
 234
 235 void die(struct pt_regs *regs, const char *str)
 236 {
 237         static int die_counter;
 238
 239         oops_enter();
 240         lgr_info_log();
 241         debug_stop_all();
 242         console_verbose();
 243         spin_lock_irq(&die_lock);
 244         bust_spinlocks(1);
 245         printk("%s: %04x [#%d] ", str, regs->int_code & 0xffff, ++die_counter);
 246 #ifdef CONFIG_PREEMPT
 247         printk("PREEMPT ");
 248 #endif
 249 #ifdef CONFIG_SMP
 250         printk("SMP ");
 251 #endif
 252 #ifdef CONFIG_DEBUG_PAGEALLOC
 253         printk("DEBUG_PAGEALLOC");
 254 #endif
 255         printk("\n");
 256         notify_die(DIE_OOPS, str, regs, 0, regs->int_code & 0xffff, SIGSEGV);
 257         show_regs(regs);
 258         bust_spinlocks(0);
 259         add_taint(TAINT_DIE);
 260         spin_unlock_irq(&die_lock);
 261         if (in_interrupt())
 262                 panic("Fatal exception in interrupt");
 263         if (panic_on_oops)
 264                 panic("Fatal exception: panic_on_oops");
 265         oops_exit();
 266         do_exit(SIGSEGV);
 267 }
 268
 269 static inline void report_user_fault(struct pt_regs *regs, int signr)
 270 {
 271         if ((task_pid_nr(current) > 1) && !show_unhandled_signals)
 272                 return;
 273         if (!unhandled_signal(current, signr))
 274                 return;
 275         if (!printk_ratelimit())
 276                 return;
 277         printk("User process fault: interruption code 0x%X ", regs->int_code);
 278         print_vma_addr("in ", regs->psw.addr & PSW_ADDR_INSN);
 279         printk("\n");
 280         show_regs(regs);
 281 }
 282
 283 int is_valid_bugaddr(unsigned long addr)
 284 {
 285         return 1;
 286 }
 287
 288 static inline void __user *get_psw_address(struct pt_regs *regs)
 289 {
 290         return (void __user *)
 291                 ((regs->psw.addr - (regs->int_code >> 16)) & PSW_ADDR_INSN);
 292 }
 293
 294 static void __kprobes do_trap(struct pt_regs *regs,
 295                               int si_signo, int si_code, char *str)
 296 {
 297         siginfo_t info;
 298
 299         if (notify_die(DIE_TRAP, str, regs, 0,
 300                        regs->int_code, si_signo) == NOTIFY_STOP)
 301                 return;
 302
 303         if (regs->psw.mask & PSW_MASK_PSTATE) {
 304                 info.si_signo = si_signo;
 305                 info.si_errno = 0;
 306                 info.si_code = si_code;
 307                 info.si_addr = get_psw_address(regs);
 308                 force_sig_info(si_signo, &info, current);
 309                 report_user_fault(regs, si_signo);
 310         } else {
 311                 const struct exception_table_entry *fixup;
 312                 fixup = search_exception_tables(regs->psw.addr & PSW_ADDR_INSN);
 313                 if (fixup)
 314                         regs->psw.addr = fixup->fixup | PSW_ADDR_AMODE;
 315                 else {
 316                         enum bug_trap_type btt;
 317
 318                         btt = report_bug(regs->psw.addr & PSW_ADDR_INSN, regs);
 319                         if (btt == BUG_TRAP_TYPE_WARN)
 320                                 return;
 321                         die(regs, str);
 322                 }
 323         }
 324 }
 325
 326 void __kprobes do_per_trap(struct pt_regs *regs)
 327 {
 328         siginfo_t info;
 329
 330         if (notify_die(DIE_SSTEP, "sstep", regs, 0, 0, SIGTRAP) == NOTIFY_STOP)
 331                 return;
 332         if (!current->ptrace)
 333                 return;
 334         info.si_signo = SIGTRAP;
 335         info.si_errno = 0;
 336         info.si_code = TRAP_HWBKPT;
 337         info.si_addr =
 338                 (void __force __user *) current->thread.per_event.address;
 339         force_sig_info(SIGTRAP, &info, current);
 340 }
 341
 342 static void default_trap_handler(struct pt_regs *regs)
 343 {
 344         if (regs->psw.mask & PSW_MASK_PSTATE) {
 345                 report_user_fault(regs, SIGSEGV);
 346                 do_exit(SIGSEGV);
 347         } else
 348                 die(regs, "Unknown program exception");
 349 }
 350
 351 #define DO_ERROR_INFO(name, signr, sicode, str) \
 352 static void name(struct pt_regs *regs) \
 353 { \
 354         do_trap(regs, signr, sicode, str); \
 355 }
 356
 357 DO_ERROR_INFO(addressing_exception, SIGILL, ILL_ILLADR,
 358               "addressing exception")
 359 DO_ERROR_INFO(execute_exception, SIGILL, ILL_ILLOPN,
 360               "execute exception")
 361 DO_ERROR_INFO(divide_exception, SIGFPE, FPE_INTDIV,
 362               "fixpoint divide exception")
 363 DO_ERROR_INFO(overflow_exception, SIGFPE, FPE_INTOVF,
 364               "fixpoint overflow exception")
 365 DO_ERROR_INFO(hfp_overflow_exception, SIGFPE, FPE_FLTOVF,
 366               "HFP overflow exception")
 367 DO_ERROR_INFO(hfp_underflow_exception, SIGFPE, FPE_FLTUND,
 368               "HFP underflow exception")
 369 DO_ERROR_INFO(hfp_significance_exception, SIGFPE, FPE_FLTRES,
 370               "HFP significance exception")
 371 DO_ERROR_INFO(hfp_divide_exception, SIGFPE, FPE_FLTDIV,
 372               "HFP divide exception")
 373 DO_ERROR_INFO(hfp_sqrt_exception, SIGFPE, FPE_FLTINV,
 374               "HFP square root exception")
 375 DO_ERROR_INFO(operand_exception, SIGILL, ILL_ILLOPN,
 376               "operand exception")
 377 DO_ERROR_INFO(privileged_op, SIGILL, ILL_PRVOPC,
 378               "privileged operation")
 379 DO_ERROR_INFO(special_op_exception, SIGILL, ILL_ILLOPN,
 380               "special operation exception")
 381 DO_ERROR_INFO(translation_exception, SIGILL, ILL_ILLOPN,
 382               "translation exception")
 383
 384 static inline void do_fp_trap(struct pt_regs *regs, int fpc)
 385 {
 386         int si_code = 0;
 387         /* FPC[2] is Data Exception Code */
 388         if ((fpc & 0x00000300) == 0) {
 389                 /* bits 6 and 7 of DXC are 0 iff IEEE exception */
 390                 if (fpc & 0x8000) /* invalid fp operation */
 391                         si_code = FPE_FLTINV;
 392                 else if (fpc & 0x4000) /* div by 0 */
 393                         si_code = FPE_FLTDIV;
 394                 else if (fpc & 0x2000) /* overflow */
 395                         si_code = FPE_FLTOVF;
 396                 else if (fpc & 0x1000) /* underflow */
 397                         si_code = FPE_FLTUND;
 398                 else if (fpc & 0x0800) /* inexact */
 399                         si_code = FPE_FLTRES;
 400         }
 401         do_trap(regs, SIGFPE, si_code, "floating point exception");
 402 }
 403
 404 static void __kprobes illegal_op(struct pt_regs *regs)
 405 {
 406         siginfo_t info;
 407         __u8 opcode[6];
 408         __u16 __user *location;
 409         int signal = 0;
 410
 411         location = get_psw_address(regs);
 412
 413         if (regs->psw.mask & PSW_MASK_PSTATE) {
 414                 if (get_user(*((__u16 *) opcode), (__u16 __user *) location))
 415                         return;
 416                 if (*((__u16 *) opcode) == S390_BREAKPOINT_U16) {
 417                         if (current->ptrace) {
 418                                 info.si_signo = SIGTRAP;
 419                                 info.si_errno = 0;
 420                                 info.si_code = TRAP_BRKPT;
 421                                 info.si_addr = location;
 422                                 force_sig_info(SIGTRAP, &info, current);
 423                         } else
 424                                 signal = SIGILL;
 425 #ifdef CONFIG_MATHEMU
 426                 } else if (opcode[0] == 0xb3) {
 427                         if (get_user(*((__u16 *) (opcode+2)), location+1))
 428                                 return;
 429                         signal = math_emu_b3(opcode, regs);
 430                 } else if (opcode[0] == 0xed) {
 431                         if (get_user(*((__u32 *) (opcode+2)),
 432                                      (__u32 __user *)(location+1)))
 433                                 return;
 434                         signal = math_emu_ed(opcode, regs);
 435                 } else if (*((__u16 *) opcode) == 0xb299) {
 436                         if (get_user(*((__u16 *) (opcode+2)), location+1))
 437                                 return;
 438                         signal = math_emu_srnm(opcode, regs);
 439                 } else if (*((__u16 *) opcode) == 0xb29c) {
 440                         if (get_user(*((__u16 *) (opcode+2)), location+1))
 441                                 return;
 442                         signal = math_emu_stfpc(opcode, regs);
 443                 } else if (*((__u16 *) opcode) == 0xb29d) {
 444                         if (get_user(*((__u16 *) (opcode+2)), location+1))
 445                                 return;
 446                         signal = math_emu_lfpc(opcode, regs);
 447 #endif
 448                 } else
 449                         signal = SIGILL;
 450         } else {
 451                 /*
 452                  * If we get an illegal op in kernel mode, send it through the
 453                  * kprobes notifier. If kprobes doesn't pick it up, SIGILL
 454                  */
 455                 if (notify_die(DIE_BPT, "bpt", regs, 0,
 456                                3, SIGTRAP) != NOTIFY_STOP)
 457                         signal = SIGILL;
 458         }
 459
 460 #ifdef CONFIG_MATHEMU
 461         if (signal == SIGFPE)
 462                 do_fp_trap(regs, current->thread.fp_regs.fpc);
 463         else if (signal == SIGSEGV)
 464                 do_trap(regs, signal, SEGV_MAPERR, "user address fault");
 465         else
 466 #endif
 467         if (signal)
 468                 do_trap(regs, signal, ILL_ILLOPC, "illegal operation");
 469 }
 470
 471
 472 #ifdef CONFIG_MATHEMU
 473 void specification_exception(struct pt_regs *regs)
 474 {
 475         __u8 opcode[6];
 476         __u16 __user *location = NULL;
 477         int signal = 0;
 478
 479         location = (__u16 __user *) get_psw_address(regs);
 480
 481         if (regs->psw.mask & PSW_MASK_PSTATE) {
 482                 get_user(*((__u16 *) opcode), location);
 483                 switch (opcode[0]) {
 484                 case 0x28: /* LDR Rx,Ry   */
 485                         signal = math_emu_ldr(opcode);
 486                         break;
 487                 case 0x38: /* LER Rx,Ry   */
 488                         signal = math_emu_ler(opcode);
 489                         break;
 490                 case 0x60: /* STD R,D(X,B) */
 491                         get_user(*((__u16 *) (opcode+2)), location+1);
 492                         signal = math_emu_std(opcode, regs);
 493                         break;
 494                 case 0x68: /* LD R,D(X,B) */
 495                         get_user(*((__u16 *) (opcode+2)), location+1);
 496                         signal = math_emu_ld(opcode, regs);
 497                         break;
 498                 case 0x70: /* STE R,D(X,B) */
 499                         get_user(*((__u16 *) (opcode+2)), location+1);
 500                         signal = math_emu_ste(opcode, regs);
 501                         break;
 502                 case 0x78: /* LE R,D(X,B) */
 503                         get_user(*((__u16 *) (opcode+2)), location+1);
 504                         signal = math_emu_le(opcode, regs);
 505                         break;
 506                 default:
 507                         signal = SIGILL;
 508                         break;
 509                 }
 510         } else
 511                 signal = SIGILL;
 512
 513         if (signal == SIGFPE)
 514                 do_fp_trap(regs, current->thread.fp_regs.fpc);
 515         else if (signal)
 516                 do_trap(regs, signal, ILL_ILLOPN, "specification exception");
 517 }
 518 #else
 519 DO_ERROR_INFO(specification_exception, SIGILL, ILL_ILLOPN,
 520               "specification exception");
 521 #endif
 522
 523 static void data_exception(struct pt_regs *regs)
 524 {
 525         __u16 __user *location;
 526         int signal = 0;
 527
 528         location = get_psw_address(regs);
 529
 530         if (MACHINE_HAS_IEEE)
 531                 asm volatile("stfpc %0" : "=m" (current->thread.fp_regs.fpc));
 532
 533 #ifdef CONFIG_MATHEMU
 534         else if (regs->psw.mask & PSW_MASK_PSTATE) {
 535                 __u8 opcode[6];
 536                 get_user(*((__u16 *) opcode), location);
 537                 switch (opcode[0]) {
 538                 case 0x28: /* LDR Rx,Ry   */
 539                         signal = math_emu_ldr(opcode);
 540                         break;
 541                 case 0x38: /* LER Rx,Ry   */
 542                         signal = math_emu_ler(opcode);
 543                         break;
 544                 case 0x60: /* STD R,D(X,B) */
 545                         get_user(*((__u16 *) (opcode+2)), location+1);
 546                         signal = math_emu_std(opcode, regs);
 547                         break;
 548                 case 0x68: /* LD R,D(X,B) */
 549                         get_user(*((__u16 *) (opcode+2)), location+1);
 550                         signal = math_emu_ld(opcode, regs);
 551                         break;
 552                 case 0x70: /* STE R,D(X,B) */
 553                         get_user(*((__u16 *) (opcode+2)), location+1);
 554                         signal = math_emu_ste(opcode, regs);
 555                         break;
 556                 case 0x78: /* LE R,D(X,B) */
 557                         get_user(*((__u16 *) (opcode+2)), location+1);
 558                         signal = math_emu_le(opcode, regs);
 559                         break;
 560                 case 0xb3:
 561                         get_user(*((__u16 *) (opcode+2)), location+1);
 562                         signal = math_emu_b3(opcode, regs);
 563                         break;
 564                 case 0xed:
 565                         get_user(*((__u32 *) (opcode+2)),
 566                                  (__u32 __user *)(location+1));
 567                         signal = math_emu_ed(opcode, regs);
 568                         break;
 569                 case 0xb2:
 570                         if (opcode[1] == 0x99) {
 571                                 get_user(*((__u16 *) (opcode+2)), location+1);
 572                                 signal = math_emu_srnm(opcode, regs);
 573                         } else if (opcode[1] == 0x9c) {
 574                                 get_user(*((__u16 *) (opcode+2)), location+1);
 575                                 signal = math_emu_stfpc(opcode, regs);
 576                         } else if (opcode[1] == 0x9d) {
 577                                 get_user(*((__u16 *) (opcode+2)), location+1);
 578                                 signal = math_emu_lfpc(opcode, regs);
 579                         } else
 580                                 signal = SIGILL;
 581                         break;
 582                 default:
 583                         signal = SIGILL;
 584                         break;
 585                 }
 586         }
 587 #endif
 588         if (current->thread.fp_regs.fpc & FPC_DXC_MASK)
 589                 signal = SIGFPE;
 590         else
 591                 signal = SIGILL;
 592         if (signal == SIGFPE)
 593                 do_fp_trap(regs, current->thread.fp_regs.fpc);
 594         else if (signal)
 595                 do_trap(regs, signal, ILL_ILLOPN, "data exception");
 596 }
 597
 598 static void space_switch_exception(struct pt_regs *regs)
 599 {
 600         /* Set user psw back to home space mode. */
 601         if (regs->psw.mask & PSW_MASK_PSTATE)
 602                 regs->psw.mask |= PSW_ASC_HOME;
 603         /* Send SIGILL. */
 604         do_trap(regs, SIGILL, ILL_PRVOPC, "space switch event");
 605 }
 606
 607 void __kprobes kernel_stack_overflow(struct pt_regs * regs)
 608 {
 609         bust_spinlocks(1);
 610         printk("Kernel stack overflow.\n");
 611         show_regs(regs);
 612         bust_spinlocks(0);
 613         panic("Corrupt kernel stack, can't continue.");
 614 }
 615
 616 /* init is done in lowcore.S and head.S */
 617
 618 void __init trap_init(void)
 619 {
 620         int i;
 621
 622         for (i = 0; i < 128; i++)
 623           pgm_check_table[i] = &default_trap_handler;
 624         pgm_check_table[1] = &illegal_op;
 625         pgm_check_table[2] = &privileged_op;
 626         pgm_check_table[3] = &execute_exception;
 627         pgm_check_table[4] = &do_protection_exception;
 628         pgm_check_table[5] = &addressing_exception;
 629         pgm_check_table[6] = &specification_exception;
 630         pgm_check_table[7] = &data_exception;
 631         pgm_check_table[8] = &overflow_exception;
 632         pgm_check_table[9] = &divide_exception;
 633         pgm_check_table[0x0A] = &overflow_exception;
 634         pgm_check_table[0x0B] = &divide_exception;
 635         pgm_check_table[0x0C] = &hfp_overflow_exception;
 636         pgm_check_table[0x0D] = &hfp_underflow_exception;
 637         pgm_check_table[0x0E] = &hfp_significance_exception;
 638         pgm_check_table[0x0F] = &hfp_divide_exception;
 639         pgm_check_table[0x10] = &do_dat_exception;
 640         pgm_check_table[0x11] = &do_dat_exception;
 641         pgm_check_table[0x12] = &translation_exception;
 642         pgm_check_table[0x13] = &special_op_exception;
 643 #ifdef CONFIG_64BIT
 644         pgm_check_table[0x38] = &do_asce_exception;
 645         pgm_check_table[0x39] = &do_dat_exception;
 646         pgm_check_table[0x3A] = &do_dat_exception;
 647         pgm_check_table[0x3B] = &do_dat_exception;
 648 #endif /* CONFIG_64BIT */
 649         pgm_check_table[0x15] = &operand_exception;
 650         pgm_check_table[0x1C] = &space_switch_exception;
 651         pgm_check_table[0x1D] = &hfp_sqrt_exception;
 652         /* Enable machine checks early. */
 653         local_mcck_enable();
 654 }