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/interrupt.h>
  29 #include <linux/delay.h>
  30 #include <linux/module.h>
  31 #include <linux/kallsyms.h>
  32 #include <linux/reboot.h>
  33
  34 #include <asm/system.h>
  35 #include <asm/uaccess.h>
  36 #include <asm/io.h>
  37 #include <asm/atomic.h>
  38 #include <asm/mathemu.h>
  39 #include <asm/cpcmd.h>
  40 #include <asm/s390_ext.h>
  41 #include <asm/lowcore.h>
  42 #include <asm/debug.h>
  43
  44 /* Called from entry.S only */
  45 extern void handle_per_exception(struct pt_regs *regs);
  46
  47 typedef void pgm_check_handler_t(struct pt_regs *, long);
  48 pgm_check_handler_t *pgm_check_table[128];
  49
  50 #ifdef CONFIG_SYSCTL
  51 #ifdef CONFIG_PROCESS_DEBUG
  52 int sysctl_userprocess_debug = 1;
  53 #else
  54 int sysctl_userprocess_debug = 0;
  55 #endif
  56 #endif
  57
  58 extern pgm_check_handler_t do_protection_exception;
  59 extern pgm_check_handler_t do_dat_exception;
  60 extern pgm_check_handler_t do_pseudo_page_fault;
  61 #ifdef CONFIG_PFAULT
  62 extern int pfault_init(void);
  63 extern void pfault_fini(void);
  64 extern void pfault_interrupt(struct pt_regs *regs, __u16 error_code);
  65 static ext_int_info_t ext_int_pfault;
  66 #endif
  67 extern pgm_check_handler_t do_monitor_call;
  68
  69 #define stack_pointer ({ void **sp; asm("la %0,0(15)" : "=&d" (sp)); sp; })
  70
  71 #ifndef CONFIG_ARCH_S390X
  72 #define FOURLONG "%08lx %08lx %08lx %08lx\n"
  73 static int kstack_depth_to_print = 12;
  74 #else /* CONFIG_ARCH_S390X */
  75 #define FOURLONG "%016lx %016lx %016lx %016lx\n"
  76 static int kstack_depth_to_print = 20;
  77 #endif /* CONFIG_ARCH_S390X */
  78
  79 /*
  80  * For show_trace we have tree different stack to consider:
  81  *   - the panic stack which is used if the kernel stack has overflown
  82  *   - the asynchronous interrupt stack (cpu related)
  83  *   - the synchronous kernel stack (process related)
  84  * The stack trace can start at any of the three stack and can potentially
  85  * touch all of them. The order is: panic stack, async stack, sync stack.
  86  */
  87 static unsigned long
  88 __show_trace(unsigned long sp, unsigned long low, unsigned long high)
  89 {
  90         struct stack_frame *sf;
  91         struct pt_regs *regs;
  92
  93         while (1) {
  94                 sp = sp & PSW_ADDR_INSN;
  95                 if (sp < low || sp > high - sizeof(*sf))
  96                         return sp;
  97                 sf = (struct stack_frame *) sp;
  98                 printk("([<%016lx>] ", sf->gprs[8] & PSW_ADDR_INSN);
  99                 print_symbol("%s)\n", sf->gprs[8] & PSW_ADDR_INSN);
 100                 /* Follow the backchain. */
 101                 while (1) {
 102                         low = sp;
 103                         sp = sf->back_chain & PSW_ADDR_INSN;
 104                         if (!sp)
 105                                 break;
 106                         if (sp <= low || sp > high - sizeof(*sf))
 107                                 return sp;
 108                         sf = (struct stack_frame *) sp;
 109                         printk(" [<%016lx>] ", sf->gprs[8] & PSW_ADDR_INSN);
 110                         print_symbol("%s\n", sf->gprs[8] & PSW_ADDR_INSN);
 111                 }
 112                 /* Zero backchain detected, check for interrupt frame. */
 113                 sp = (unsigned long) (sf + 1);
 114                 if (sp <= low || sp > high - sizeof(*regs))
 115                         return sp;
 116                 regs = (struct pt_regs *) sp;
 117                 printk(" [<%016lx>] ", regs->psw.addr & PSW_ADDR_INSN);
 118                 print_symbol("%s\n", regs->psw.addr & PSW_ADDR_INSN);
 119                 low = sp;
 120                 sp = regs->gprs[15];
 121         }
 122 }
 123
 124 void show_trace(struct task_struct *task, unsigned long * stack)
 125 {
 126         register unsigned long __r15 asm ("15");
 127         unsigned long sp;
 128
 129         sp = (unsigned long) stack;
 130         if (!sp)
 131                 sp = task ? task->thread.ksp : __r15;
 132         printk("Call Trace:\n");
 133 #ifdef CONFIG_CHECK_STACK
 134         sp = __show_trace(sp, S390_lowcore.panic_stack - 4096,
 135                           S390_lowcore.panic_stack);
 136 #endif
 137         sp = __show_trace(sp, S390_lowcore.async_stack - ASYNC_SIZE,
 138                           S390_lowcore.async_stack);
 139         if (task)
 140                 __show_trace(sp, (unsigned long) task->thread_info,
 141                              (unsigned long) task->thread_info + THREAD_SIZE);
 142         else
 143                 __show_trace(sp, S390_lowcore.thread_info,
 144                              S390_lowcore.thread_info + THREAD_SIZE);
 145         printk("\n");
 146 }
 147
 148 void show_stack(struct task_struct *task, unsigned long *sp)
 149 {
 150         register unsigned long * __r15 asm ("15");
 151         unsigned long *stack;
 152         int i;
 153
 154         // debugging aid: "show_stack(NULL);" prints the
 155         // back trace for this cpu.
 156
 157         if (!sp)
 158                 sp = task ? (unsigned long *) task->thread.ksp : __r15;
 159
 160         stack = sp;
 161         for (i = 0; i < kstack_depth_to_print; i++) {
 162                 if (((addr_t) stack & (THREAD_SIZE-1)) == 0)
 163                         break;
 164                 if (i && ((i * sizeof (long) % 32) == 0))
 165                         printk("\n       ");
 166                 printk("%p ", (void *)*stack++);
 167         }
 168         printk("\n");
 169         show_trace(task, sp);
 170 }
 171
 172 /*
 173  * The architecture-independent dump_stack generator
 174  */
 175 void dump_stack(void)
 176 {
 177         show_stack(0, 0);
 178 }
 179
 180 EXPORT_SYMBOL(dump_stack);
 181
 182 void show_registers(struct pt_regs *regs)
 183 {
 184         mm_segment_t old_fs;
 185         char *mode;
 186         int i;
 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("%s GPRS: " FOURLONG, mode,
 194                regs->gprs[0], regs->gprs[1], regs->gprs[2], regs->gprs[3]);
 195         printk("           " FOURLONG,
 196                regs->gprs[4], regs->gprs[5], regs->gprs[6], regs->gprs[7]);
 197         printk("           " FOURLONG,
 198                regs->gprs[8], regs->gprs[9], regs->gprs[10], regs->gprs[11]);
 199         printk("           " FOURLONG,
 200                regs->gprs[12], regs->gprs[13], regs->gprs[14], regs->gprs[15]);
 201
 202 #if 0
 203         /* FIXME: this isn't needed any more but it changes the ksymoops
 204          * input. To remove or not to remove ... */
 205         save_access_regs(regs->acrs);
 206         printk("%s ACRS: %08x %08x %08x %08x\n", mode,
 207                regs->acrs[0], regs->acrs[1], regs->acrs[2], regs->acrs[3]);
 208         printk("           %08x %08x %08x %08x\n",
 209                regs->acrs[4], regs->acrs[5], regs->acrs[6], regs->acrs[7]);
 210         printk("           %08x %08x %08x %08x\n",
 211                regs->acrs[8], regs->acrs[9], regs->acrs[10], regs->acrs[11]);
 212         printk("           %08x %08x %08x %08x\n",
 213                regs->acrs[12], regs->acrs[13], regs->acrs[14], regs->acrs[15]);
 214 #endif
 215
 216         /*
 217          * Print the first 20 byte of the instruction stream at the
 218          * time of the fault.
 219          */
 220         old_fs = get_fs();
 221         if (regs->psw.mask & PSW_MASK_PSTATE)
 222                 set_fs(USER_DS);
 223         else
 224                 set_fs(KERNEL_DS);
 225         printk("%s Code: ", mode);
 226         for (i = 0; i < 20; i++) {
 227                 unsigned char c;
 228                 if (__get_user(c, (char __user *)(regs->psw.addr + i))) {
 229                         printk(" Bad PSW.");
 230                         break;
 231                 }
 232                 printk("%02x ", c);
 233         }
 234         set_fs(old_fs);
 235
 236         printk("\n");
 237 }
 238
 239 /* This is called from fs/proc/array.c */
 240 char *task_show_regs(struct task_struct *task, char *buffer)
 241 {
 242         struct pt_regs *regs;
 243
 244         regs = __KSTK_PTREGS(task);
 245         buffer += sprintf(buffer, "task: %p, ksp: %p\n",
 246                        task, (void *)task->thread.ksp);
 247         buffer += sprintf(buffer, "User PSW : %p %p\n",
 248                        (void *) regs->psw.mask, (void *)regs->psw.addr);
 249
 250         buffer += sprintf(buffer, "User GPRS: " FOURLONG,
 251                           regs->gprs[0], regs->gprs[1],
 252                           regs->gprs[2], regs->gprs[3]);
 253         buffer += sprintf(buffer, "           " FOURLONG,
 254                           regs->gprs[4], regs->gprs[5],
 255                           regs->gprs[6], regs->gprs[7]);
 256         buffer += sprintf(buffer, "           " FOURLONG,
 257                           regs->gprs[8], regs->gprs[9],
 258                           regs->gprs[10], regs->gprs[11]);
 259         buffer += sprintf(buffer, "           " FOURLONG,
 260                           regs->gprs[12], regs->gprs[13],
 261                           regs->gprs[14], regs->gprs[15]);
 262         buffer += sprintf(buffer, "User ACRS: %08x %08x %08x %08x\n",
 263                           task->thread.acrs[0], task->thread.acrs[1],
 264                           task->thread.acrs[2], task->thread.acrs[3]);
 265         buffer += sprintf(buffer, "           %08x %08x %08x %08x\n",
 266                           task->thread.acrs[4], task->thread.acrs[5],
 267                           task->thread.acrs[6], task->thread.acrs[7]);
 268         buffer += sprintf(buffer, "           %08x %08x %08x %08x\n",
 269                           task->thread.acrs[8], task->thread.acrs[9],
 270                           task->thread.acrs[10], task->thread.acrs[11]);
 271         buffer += sprintf(buffer, "           %08x %08x %08x %08x\n",
 272                           task->thread.acrs[12], task->thread.acrs[13],
 273                           task->thread.acrs[14], task->thread.acrs[15]);
 274         return buffer;
 275 }
 276
 277 DEFINE_SPINLOCK(die_lock);
 278
 279 void die(const char * str, struct pt_regs * regs, long err)
 280 {
 281         static int die_counter;
 282
 283         debug_stop_all();
 284         console_verbose();
 285         spin_lock_irq(&die_lock);
 286         bust_spinlocks(1);
 287         printk("%s: %04lx [#%d]\n", str, err & 0xffff, ++die_counter);
 288         show_regs(regs);
 289         bust_spinlocks(0);
 290         spin_unlock_irq(&die_lock);
 291         if (in_interrupt())
 292                 panic("Fatal exception in interrupt");
 293         if (panic_on_oops)
 294                 panic("Fatal exception: panic_on_oops");
 295         do_exit(SIGSEGV);
 296 }
 297
 298 static void inline
 299 report_user_fault(long interruption_code, struct pt_regs *regs)
 300 {
 301 #if defined(CONFIG_SYSCTL)
 302         if (!sysctl_userprocess_debug)
 303                 return;
 304 #endif
 305 #if defined(CONFIG_SYSCTL) || defined(CONFIG_PROCESS_DEBUG)
 306         printk("User process fault: interruption code 0x%lX\n",
 307                interruption_code);
 308         show_regs(regs);
 309 #endif
 310 }
 311
 312 static void inline do_trap(long interruption_code, int signr, char *str,
 313                            struct pt_regs *regs, siginfo_t *info)
 314 {
 315         /*
 316          * We got all needed information from the lowcore and can
 317          * now safely switch on interrupts.
 318          */
 319         if (regs->psw.mask & PSW_MASK_PSTATE)
 320                 local_irq_enable();
 321
 322         if (regs->psw.mask & PSW_MASK_PSTATE) {
 323                 struct task_struct *tsk = current;
 324
 325                 tsk->thread.trap_no = interruption_code & 0xffff;
 326                 force_sig_info(signr, info, tsk);
 327                 report_user_fault(interruption_code, regs);
 328         } else {
 329                 const struct exception_table_entry *fixup;
 330                 fixup = search_exception_tables(regs->psw.addr & PSW_ADDR_INSN);
 331                 if (fixup)
 332                         regs->psw.addr = fixup->fixup | PSW_ADDR_AMODE;
 333                 else
 334                         die(str, regs, interruption_code);
 335         }
 336 }
 337
 338 static inline void *get_check_address(struct pt_regs *regs)
 339 {
 340         return (void *)((regs->psw.addr-S390_lowcore.pgm_ilc) & PSW_ADDR_INSN);
 341 }
 342
 343 void do_single_step(struct pt_regs *regs)
 344 {
 345         if ((current->ptrace & PT_PTRACED) != 0)
 346                 force_sig(SIGTRAP, current);
 347 }
 348
 349 asmlinkage void
 350 default_trap_handler(struct pt_regs * regs, long interruption_code)
 351 {
 352         if (regs->psw.mask & PSW_MASK_PSTATE) {
 353                 local_irq_enable();
 354                 do_exit(SIGSEGV);
 355                 report_user_fault(interruption_code, regs);
 356         } else
 357                 die("Unknown program exception", regs, interruption_code);
 358 }
 359
 360 #define DO_ERROR_INFO(signr, str, name, sicode, siaddr) \
 361 asmlinkage void name(struct pt_regs * regs, long interruption_code) \
 362 { \
 363         siginfo_t info; \
 364         info.si_signo = signr; \
 365         info.si_errno = 0; \
 366         info.si_code = sicode; \
 367         info.si_addr = (void *)siaddr; \
 368         do_trap(interruption_code, signr, str, regs, &info); \
 369 }
 370
 371 DO_ERROR_INFO(SIGILL, "addressing exception", addressing_exception,
 372               ILL_ILLADR, get_check_address(regs))
 373 DO_ERROR_INFO(SIGILL,  "execute exception", execute_exception,
 374               ILL_ILLOPN, get_check_address(regs))
 375 DO_ERROR_INFO(SIGFPE,  "fixpoint divide exception", divide_exception,
 376               FPE_INTDIV, get_check_address(regs))
 377 DO_ERROR_INFO(SIGFPE,  "fixpoint overflow exception", overflow_exception,
 378               FPE_INTOVF, get_check_address(regs))
 379 DO_ERROR_INFO(SIGFPE,  "HFP overflow exception", hfp_overflow_exception,
 380               FPE_FLTOVF, get_check_address(regs))
 381 DO_ERROR_INFO(SIGFPE,  "HFP underflow exception", hfp_underflow_exception,
 382               FPE_FLTUND, get_check_address(regs))
 383 DO_ERROR_INFO(SIGFPE,  "HFP significance exception", hfp_significance_exception,
 384               FPE_FLTRES, get_check_address(regs))
 385 DO_ERROR_INFO(SIGFPE,  "HFP divide exception", hfp_divide_exception,
 386               FPE_FLTDIV, get_check_address(regs))
 387 DO_ERROR_INFO(SIGFPE,  "HFP square root exception", hfp_sqrt_exception,
 388               FPE_FLTINV, get_check_address(regs))
 389 DO_ERROR_INFO(SIGILL,  "operand exception", operand_exception,
 390               ILL_ILLOPN, get_check_address(regs))
 391 DO_ERROR_INFO(SIGILL,  "privileged operation", privileged_op,
 392               ILL_PRVOPC, get_check_address(regs))
 393 DO_ERROR_INFO(SIGILL,  "special operation exception", special_op_exception,
 394               ILL_ILLOPN, get_check_address(regs))
 395 DO_ERROR_INFO(SIGILL,  "translation exception", translation_exception,
 396               ILL_ILLOPN, get_check_address(regs))
 397
 398 static inline void
 399 do_fp_trap(struct pt_regs *regs, void *location,
 400            int fpc, long interruption_code)
 401 {
 402         siginfo_t si;
 403
 404         si.si_signo = SIGFPE;
 405         si.si_errno = 0;
 406         si.si_addr = location;
 407         si.si_code = 0;
 408         /* FPC[2] is Data Exception Code */
 409         if ((fpc & 0x00000300) == 0) {
 410                 /* bits 6 and 7 of DXC are 0 iff IEEE exception */
 411                 if (fpc & 0x8000) /* invalid fp operation */
 412                         si.si_code = FPE_FLTINV;
 413                 else if (fpc & 0x4000) /* div by 0 */
 414                         si.si_code = FPE_FLTDIV;
 415                 else if (fpc & 0x2000) /* overflow */
 416                         si.si_code = FPE_FLTOVF;
 417                 else if (fpc & 0x1000) /* underflow */
 418                         si.si_code = FPE_FLTUND;
 419                 else if (fpc & 0x0800) /* inexact */
 420                         si.si_code = FPE_FLTRES;
 421         }
 422         current->thread.ieee_instruction_pointer = (addr_t) location;
 423         do_trap(interruption_code, SIGFPE,
 424                 "floating point exception", regs, &si);
 425 }
 426
 427 asmlinkage void illegal_op(struct pt_regs * regs, long interruption_code)
 428 {
 429         siginfo_t info;
 430         __u8 opcode[6];
 431         __u16 *location;
 432         int signal = 0;
 433
 434         location = (__u16 *) get_check_address(regs);
 435
 436         /*
 437          * We got all needed information from the lowcore and can
 438          * now safely switch on interrupts.
 439          */
 440         if (regs->psw.mask & PSW_MASK_PSTATE)
 441                 local_irq_enable();
 442
 443         if (regs->psw.mask & PSW_MASK_PSTATE) {
 444                 get_user(*((__u16 *) opcode), (__u16 __user *) location);
 445                 if (*((__u16 *) opcode) == S390_BREAKPOINT_U16) {
 446                         if (current->ptrace & PT_PTRACED)
 447                                 force_sig(SIGTRAP, current);
 448                         else
 449                                 signal = SIGILL;
 450 #ifdef CONFIG_MATHEMU
 451                 } else if (opcode[0] == 0xb3) {
 452                         get_user(*((__u16 *) (opcode+2)), location+1);
 453                         signal = math_emu_b3(opcode, regs);
 454                 } else if (opcode[0] == 0xed) {
 455                         get_user(*((__u32 *) (opcode+2)),
 456                                  (__u32 *)(location+1));
 457                         signal = math_emu_ed(opcode, regs);
 458                 } else if (*((__u16 *) opcode) == 0xb299) {
 459                         get_user(*((__u16 *) (opcode+2)), location+1);
 460                         signal = math_emu_srnm(opcode, regs);
 461                 } else if (*((__u16 *) opcode) == 0xb29c) {
 462                         get_user(*((__u16 *) (opcode+2)), location+1);
 463                         signal = math_emu_stfpc(opcode, regs);
 464                 } else if (*((__u16 *) opcode) == 0xb29d) {
 465                         get_user(*((__u16 *) (opcode+2)), location+1);
 466                         signal = math_emu_lfpc(opcode, regs);
 467 #endif
 468                 } else
 469                         signal = SIGILL;
 470         } else
 471                 signal = SIGILL;
 472
 473 #ifdef CONFIG_MATHEMU
 474         if (signal == SIGFPE)
 475                 do_fp_trap(regs, location,
 476                            current->thread.fp_regs.fpc, interruption_code);
 477         else if (signal == SIGSEGV) {
 478                 info.si_signo = signal;
 479                 info.si_errno = 0;
 480                 info.si_code = SEGV_MAPERR;
 481                 info.si_addr = (void *) location;
 482                 do_trap(interruption_code, signal,
 483                         "user address fault", regs, &info);
 484         } else
 485 #endif
 486         if (signal) {
 487                 info.si_signo = signal;
 488                 info.si_errno = 0;
 489                 info.si_code = ILL_ILLOPC;
 490                 info.si_addr = (void *) location;
 491                 do_trap(interruption_code, signal,
 492                         "illegal operation", regs, &info);
 493         }
 494 }
 495
 496
 497 #ifdef CONFIG_MATHEMU
 498 asmlinkage void
 499 specification_exception(struct pt_regs * regs, long interruption_code)
 500 {
 501         __u8 opcode[6];
 502         __u16 *location = NULL;
 503         int signal = 0;
 504
 505         location = (__u16 *) get_check_address(regs);
 506
 507         /*
 508          * We got all needed information from the lowcore and can
 509          * now safely switch on interrupts.
 510          */
 511         if (regs->psw.mask & PSW_MASK_PSTATE)
 512                 local_irq_enable();
 513
 514         if (regs->psw.mask & PSW_MASK_PSTATE) {
 515                 get_user(*((__u16 *) opcode), location);
 516                 switch (opcode[0]) {
 517                 case 0x28: /* LDR Rx,Ry   */
 518                         signal = math_emu_ldr(opcode);
 519                         break;
 520                 case 0x38: /* LER Rx,Ry   */
 521                         signal = math_emu_ler(opcode);
 522                         break;
 523                 case 0x60: /* STD R,D(X,B) */
 524                         get_user(*((__u16 *) (opcode+2)), location+1);
 525                         signal = math_emu_std(opcode, regs);
 526                         break;
 527                 case 0x68: /* LD R,D(X,B) */
 528                         get_user(*((__u16 *) (opcode+2)), location+1);
 529                         signal = math_emu_ld(opcode, regs);
 530                         break;
 531                 case 0x70: /* STE R,D(X,B) */
 532                         get_user(*((__u16 *) (opcode+2)), location+1);
 533                         signal = math_emu_ste(opcode, regs);
 534                         break;
 535                 case 0x78: /* LE R,D(X,B) */
 536                         get_user(*((__u16 *) (opcode+2)), location+1);
 537                         signal = math_emu_le(opcode, regs);
 538                         break;
 539                 default:
 540                         signal = SIGILL;
 541                         break;
 542                 }
 543         } else
 544                 signal = SIGILL;
 545
 546         if (signal == SIGFPE)
 547                 do_fp_trap(regs, location,
 548                            current->thread.fp_regs.fpc, interruption_code);
 549         else if (signal) {
 550                 siginfo_t info;
 551                 info.si_signo = signal;
 552                 info.si_errno = 0;
 553                 info.si_code = ILL_ILLOPN;
 554                 info.si_addr = location;
 555                 do_trap(interruption_code, signal,
 556                         "specification exception", regs, &info);
 557         }
 558 }
 559 #else
 560 DO_ERROR_INFO(SIGILL, "specification exception", specification_exception,
 561               ILL_ILLOPN, get_check_address(regs));
 562 #endif
 563
 564 asmlinkage void data_exception(struct pt_regs * regs, long interruption_code)
 565 {
 566         __u16 *location;
 567         int signal = 0;
 568
 569         location = (__u16 *) get_check_address(regs);
 570
 571         /*
 572          * We got all needed information from the lowcore and can
 573          * now safely switch on interrupts.
 574          */
 575         if (regs->psw.mask & PSW_MASK_PSTATE)
 576                 local_irq_enable();
 577
 578         if (MACHINE_HAS_IEEE)
 579                 __asm__ volatile ("stfpc %0\n\t"
 580                                   : "=m" (current->thread.fp_regs.fpc));
 581
 582 #ifdef CONFIG_MATHEMU
 583         else if (regs->psw.mask & PSW_MASK_PSTATE) {
 584                 __u8 opcode[6];
 585                 get_user(*((__u16 *) opcode), location);
 586                 switch (opcode[0]) {
 587                 case 0x28: /* LDR Rx,Ry   */
 588                         signal = math_emu_ldr(opcode);
 589                         break;
 590                 case 0x38: /* LER Rx,Ry   */
 591                         signal = math_emu_ler(opcode);
 592                         break;
 593                 case 0x60: /* STD R,D(X,B) */
 594                         get_user(*((__u16 *) (opcode+2)), location+1);
 595                         signal = math_emu_std(opcode, regs);
 596                         break;
 597                 case 0x68: /* LD R,D(X,B) */
 598                         get_user(*((__u16 *) (opcode+2)), location+1);
 599                         signal = math_emu_ld(opcode, regs);
 600                         break;
 601                 case 0x70: /* STE R,D(X,B) */
 602                         get_user(*((__u16 *) (opcode+2)), location+1);
 603                         signal = math_emu_ste(opcode, regs);
 604                         break;
 605                 case 0x78: /* LE R,D(X,B) */
 606                         get_user(*((__u16 *) (opcode+2)), location+1);
 607                         signal = math_emu_le(opcode, regs);
 608                         break;
 609                 case 0xb3:
 610                         get_user(*((__u16 *) (opcode+2)), location+1);
 611                         signal = math_emu_b3(opcode, regs);
 612                         break;
 613                 case 0xed:
 614                         get_user(*((__u32 *) (opcode+2)),
 615                                  (__u32 *)(location+1));
 616                         signal = math_emu_ed(opcode, regs);
 617                         break;
 618                 case 0xb2:
 619                         if (opcode[1] == 0x99) {
 620                                 get_user(*((__u16 *) (opcode+2)), location+1);
 621                                 signal = math_emu_srnm(opcode, regs);
 622                         } else if (opcode[1] == 0x9c) {
 623                                 get_user(*((__u16 *) (opcode+2)), location+1);
 624                                 signal = math_emu_stfpc(opcode, regs);
 625                         } else if (opcode[1] == 0x9d) {
 626                                 get_user(*((__u16 *) (opcode+2)), location+1);
 627                                 signal = math_emu_lfpc(opcode, regs);
 628                         } else
 629                                 signal = SIGILL;
 630                         break;
 631                 default:
 632                         signal = SIGILL;
 633                         break;
 634                 }
 635         }
 636 #endif
 637         if (current->thread.fp_regs.fpc & FPC_DXC_MASK)
 638                 signal = SIGFPE;
 639         else
 640                 signal = SIGILL;
 641         if (signal == SIGFPE)
 642                 do_fp_trap(regs, location,
 643                            current->thread.fp_regs.fpc, interruption_code);
 644         else if (signal) {
 645                 siginfo_t info;
 646                 info.si_signo = signal;
 647                 info.si_errno = 0;
 648                 info.si_code = ILL_ILLOPN;
 649                 info.si_addr = location;
 650                 do_trap(interruption_code, signal,
 651                         "data exception", regs, &info);
 652         }
 653 }
 654
 655 asmlinkage void space_switch_exception(struct pt_regs * regs, long int_code)
 656 {
 657         siginfo_t info;
 658
 659         /* Set user psw back to home space mode. */
 660         if (regs->psw.mask & PSW_MASK_PSTATE)
 661                 regs->psw.mask |= PSW_ASC_HOME;
 662         /* Send SIGILL. */
 663         info.si_signo = SIGILL;
 664         info.si_errno = 0;
 665         info.si_code = ILL_PRVOPC;
 666         info.si_addr = get_check_address(regs);
 667         do_trap(int_code, SIGILL, "space switch event", regs, &info);
 668 }
 669
 670 asmlinkage void kernel_stack_overflow(struct pt_regs * regs)
 671 {
 672         bust_spinlocks(1);
 673         printk("Kernel stack overflow.\n");
 674         show_regs(regs);
 675         bust_spinlocks(0);
 676         panic("Corrupt kernel stack, can't continue.");
 677 }
 678
 679 #ifndef CONFIG_ARCH_S390X
 680 static int
 681 pagex_reboot_event(struct notifier_block *this, unsigned long event, void *ptr)
 682 {
 683         if (MACHINE_IS_VM)
 684                 cpcmd("SET PAGEX OFF", NULL, 0, NULL);
 685         return NOTIFY_DONE;
 686 }
 687
 688 static struct notifier_block pagex_reboot_notifier = {
 689         .notifier_call = &pagex_reboot_event,
 690 };
 691 #endif
 692
 693 /* init is done in lowcore.S and head.S */
 694
 695 void __init trap_init(void)
 696 {
 697         int i;
 698
 699         for (i = 0; i < 128; i++)
 700           pgm_check_table[i] = &default_trap_handler;
 701         pgm_check_table[1] = &illegal_op;
 702         pgm_check_table[2] = &privileged_op;
 703         pgm_check_table[3] = &execute_exception;
 704         pgm_check_table[4] = &do_protection_exception;
 705         pgm_check_table[5] = &addressing_exception;
 706         pgm_check_table[6] = &specification_exception;
 707         pgm_check_table[7] = &data_exception;
 708         pgm_check_table[8] = &overflow_exception;
 709         pgm_check_table[9] = &divide_exception;
 710         pgm_check_table[0x0A] = &overflow_exception;
 711         pgm_check_table[0x0B] = &divide_exception;
 712         pgm_check_table[0x0C] = &hfp_overflow_exception;
 713         pgm_check_table[0x0D] = &hfp_underflow_exception;
 714         pgm_check_table[0x0E] = &hfp_significance_exception;
 715         pgm_check_table[0x0F] = &hfp_divide_exception;
 716         pgm_check_table[0x10] = &do_dat_exception;
 717         pgm_check_table[0x11] = &do_dat_exception;
 718         pgm_check_table[0x12] = &translation_exception;
 719         pgm_check_table[0x13] = &special_op_exception;
 720 #ifndef CONFIG_ARCH_S390X
 721         pgm_check_table[0x14] = &do_pseudo_page_fault;
 722 #else /* CONFIG_ARCH_S390X */
 723         pgm_check_table[0x38] = &do_dat_exception;
 724         pgm_check_table[0x39] = &do_dat_exception;
 725         pgm_check_table[0x3A] = &do_dat_exception;
 726         pgm_check_table[0x3B] = &do_dat_exception;
 727 #endif /* CONFIG_ARCH_S390X */
 728         pgm_check_table[0x15] = &operand_exception;
 729         pgm_check_table[0x1C] = &space_switch_exception;
 730         pgm_check_table[0x1D] = &hfp_sqrt_exception;
 731         pgm_check_table[0x40] = &do_monitor_call;
 732
 733         if (MACHINE_IS_VM) {
 734                 /*
 735                  * First try to get pfault pseudo page faults going.
 736                  * If this isn't available turn on pagex page faults.
 737                  */
 738 #ifdef CONFIG_PFAULT
 739                 /* request the 0x2603 external interrupt */
 740                 if (register_early_external_interrupt(0x2603, pfault_interrupt,
 741                                                       &ext_int_pfault) != 0)
 742                         panic("Couldn't request external interrupt 0x2603");
 743
 744                 if (pfault_init() == 0)
 745                         return;
 746
 747                 /* Tough luck, no pfault. */
 748                 unregister_early_external_interrupt(0x2603, pfault_interrupt,
 749                                                     &ext_int_pfault);
 750 #endif
 751 #ifndef CONFIG_ARCH_S390X
 752                 register_reboot_notifier(&pagex_reboot_notifier);
 753                 cpcmd("SET PAGEX ON", NULL, 0, NULL);
 754 #endif
 755         }
 756 }