arch/powerpc/kernel/traps.c

   1 /*
   2  *  Copyright (C) 1995-1996  Gary Thomas (gdt@linuxppc.org)
   3  *
   4  *  This program is free software; you can redistribute it and/or
   5  *  modify it under the terms of the GNU General Public License
   6  *  as published by the Free Software Foundation; either version
   7  *  2 of the License, or (at your option) any later version.
   8  *
   9  *  Modified by Cort Dougan (cort@cs.nmt.edu)
  10  *  and Paul Mackerras (paulus@samba.org)
  11  */
  12
  13 /*
  14  * This file handles the architecture-dependent parts of hardware exceptions
  15  */
  16
  17 #include <linux/config.h>
  18 #include <linux/errno.h>
  19 #include <linux/sched.h>
  20 #include <linux/kernel.h>
  21 #include <linux/mm.h>
  22 #include <linux/stddef.h>
  23 #include <linux/unistd.h>
  24 #include <linux/ptrace.h>
  25 #include <linux/slab.h>
  26 #include <linux/user.h>
  27 #include <linux/a.out.h>
  28 #include <linux/interrupt.h>
  29 #include <linux/init.h>
  30 #include <linux/module.h>
  31 #include <linux/prctl.h>
  32 #include <linux/delay.h>
  33 #include <linux/kprobes.h>
  34 #include <linux/kexec.h>
  35
  36 #include <asm/kdebug.h>
  37 #include <asm/pgtable.h>
  38 #include <asm/uaccess.h>
  39 #include <asm/system.h>
  40 #include <asm/io.h>
  41 #include <asm/machdep.h>
  42 #include <asm/rtas.h>
  43 #include <asm/pmc.h>
  44 #ifdef CONFIG_PPC32
  45 #include <asm/reg.h>
  46 #endif
  47 #ifdef CONFIG_PMAC_BACKLIGHT
  48 #include <asm/backlight.h>
  49 #endif
  50 #ifdef CONFIG_PPC64
  51 #include <asm/firmware.h>
  52 #include <asm/processor.h>
  53 #endif
  54
  55 #ifdef CONFIG_PPC64     /* XXX */
  56 #define _IO_BASE        pci_io_base
  57 #endif
  58
  59 #ifdef CONFIG_DEBUGGER
  60 int (*__debugger)(struct pt_regs *regs);
  61 int (*__debugger_ipi)(struct pt_regs *regs);
  62 int (*__debugger_bpt)(struct pt_regs *regs);
  63 int (*__debugger_sstep)(struct pt_regs *regs);
  64 int (*__debugger_iabr_match)(struct pt_regs *regs);
  65 int (*__debugger_dabr_match)(struct pt_regs *regs);
  66 int (*__debugger_fault_handler)(struct pt_regs *regs);
  67
  68 EXPORT_SYMBOL(__debugger);
  69 EXPORT_SYMBOL(__debugger_ipi);
  70 EXPORT_SYMBOL(__debugger_bpt);
  71 EXPORT_SYMBOL(__debugger_sstep);
  72 EXPORT_SYMBOL(__debugger_iabr_match);
  73 EXPORT_SYMBOL(__debugger_dabr_match);
  74 EXPORT_SYMBOL(__debugger_fault_handler);
  75 #endif
  76
  77 struct notifier_block *powerpc_die_chain;
  78 static DEFINE_SPINLOCK(die_notifier_lock);
  79
  80 int register_die_notifier(struct notifier_block *nb)
  81 {
  82         int err = 0;
  83         unsigned long flags;
  84
  85         spin_lock_irqsave(&die_notifier_lock, flags);
  86         err = notifier_chain_register(&powerpc_die_chain, nb);
  87         spin_unlock_irqrestore(&die_notifier_lock, flags);
  88         return err;
  89 }
  90
  91 /*
  92  * Trap & Exception support
  93  */
  94
  95 static DEFINE_SPINLOCK(die_lock);
  96
  97 int die(const char *str, struct pt_regs *regs, long err)
  98 {
  99         static int die_counter, crash_dump_start = 0;
 100         int nl = 0;
 101
 102         if (debugger(regs))
 103                 return 1;
 104
 105         console_verbose();
 106         spin_lock_irq(&die_lock);
 107         bust_spinlocks(1);
 108 #ifdef CONFIG_PMAC_BACKLIGHT
 109         if (_machine == _MACH_Pmac) {
 110                 set_backlight_enable(1);
 111                 set_backlight_level(BACKLIGHT_MAX);
 112         }
 113 #endif
 114         printk("Oops: %s, sig: %ld [#%d]\n", str, err, ++die_counter);
 115 #ifdef CONFIG_PREEMPT
 116         printk("PREEMPT ");
 117         nl = 1;
 118 #endif
 119 #ifdef CONFIG_SMP
 120         printk("SMP NR_CPUS=%d ", NR_CPUS);
 121         nl = 1;
 122 #endif
 123 #ifdef CONFIG_DEBUG_PAGEALLOC
 124         printk("DEBUG_PAGEALLOC ");
 125         nl = 1;
 126 #endif
 127 #ifdef CONFIG_NUMA
 128         printk("NUMA ");
 129         nl = 1;
 130 #endif
 131 #ifdef CONFIG_PPC64
 132         switch (_machine) {
 133         case PLATFORM_PSERIES:
 134                 printk("PSERIES ");
 135                 nl = 1;
 136                 break;
 137         case PLATFORM_PSERIES_LPAR:
 138                 printk("PSERIES LPAR ");
 139                 nl = 1;
 140                 break;
 141         case PLATFORM_ISERIES_LPAR:
 142                 printk("ISERIES LPAR ");
 143                 nl = 1;
 144                 break;
 145         case PLATFORM_POWERMAC:
 146                 printk("POWERMAC ");
 147                 nl = 1;
 148                 break;
 149         case PLATFORM_CELL:
 150                 printk("CELL ");
 151                 nl = 1;
 152                 break;
 153         }
 154 #endif
 155         if (nl)
 156                 printk("\n");
 157         print_modules();
 158         show_regs(regs);
 159         bust_spinlocks(0);
 160
 161         if (!crash_dump_start && kexec_should_crash(current)) {
 162                 crash_dump_start = 1;
 163                 spin_unlock_irq(&die_lock);
 164                 crash_kexec(regs);
 165                 /* NOTREACHED */
 166         }
 167         spin_unlock_irq(&die_lock);
 168         if (crash_dump_start)
 169                 /*
 170                  * Only for soft-reset: Other CPUs will be responded to an IPI
 171                  * sent by first kexec CPU.
 172                  */
 173                 for(;;)
 174                         ;
 175
 176         if (in_interrupt())
 177                 panic("Fatal exception in interrupt");
 178
 179         if (panic_on_oops) {
 180 #ifdef CONFIG_PPC64
 181                 printk(KERN_EMERG "Fatal exception: panic in 5 seconds\n");
 182                 ssleep(5);
 183 #endif
 184                 panic("Fatal exception");
 185         }
 186         do_exit(err);
 187
 188         return 0;
 189 }
 190
 191 void _exception(int signr, struct pt_regs *regs, int code, unsigned long addr)
 192 {
 193         siginfo_t info;
 194
 195         if (!user_mode(regs)) {
 196                 if (die("Exception in kernel mode", regs, signr))
 197                         return;
 198         }
 199
 200         memset(&info, 0, sizeof(info));
 201         info.si_signo = signr;
 202         info.si_code = code;
 203         info.si_addr = (void __user *) addr;
 204         force_sig_info(signr, &info, current);
 205
 206         /*
 207          * Init gets no signals that it doesn't have a handler for.
 208          * That's all very well, but if it has caused a synchronous
 209          * exception and we ignore the resulting signal, it will just
 210          * generate the same exception over and over again and we get
 211          * nowhere.  Better to kill it and let the kernel panic.
 212          */
 213         if (current->pid == 1) {
 214                 __sighandler_t handler;
 215
 216                 spin_lock_irq(&current->sighand->siglock);
 217                 handler = current->sighand->action[signr-1].sa.sa_handler;
 218                 spin_unlock_irq(&current->sighand->siglock);
 219                 if (handler == SIG_DFL) {
 220                         /* init has generated a synchronous exception
 221                            and it doesn't have a handler for the signal */
 222                         printk(KERN_CRIT "init has generated signal %d "
 223                                "but has no handler for it\n", signr);
 224                         do_exit(signr);
 225                 }
 226         }
 227 }
 228
 229 #ifdef CONFIG_PPC64
 230 void system_reset_exception(struct pt_regs *regs)
 231 {
 232         /* See if any machine dependent calls */
 233         if (ppc_md.system_reset_exception) {
 234                 if (ppc_md.system_reset_exception(regs))
 235                         return;
 236         }
 237
 238         die("System Reset", regs, SIGABRT);
 239
 240         /* Must die if the interrupt is not recoverable */
 241         if (!(regs->msr & MSR_RI))
 242                 panic("Unrecoverable System Reset");
 243
 244         /* What should we do here? We could issue a shutdown or hard reset. */
 245 }
 246 #endif
 247
 248 /*
 249  * I/O accesses can cause machine checks on powermacs.
 250  * Check if the NIP corresponds to the address of a sync
 251  * instruction for which there is an entry in the exception
 252  * table.
 253  * Note that the 601 only takes a machine check on TEA
 254  * (transfer error ack) signal assertion, and does not
 255  * set any of the top 16 bits of SRR1.
 256  *  -- paulus.
 257  */
 258 static inline int check_io_access(struct pt_regs *regs)
 259 {
 260 #ifdef CONFIG_PPC_PMAC
 261         unsigned long msr = regs->msr;
 262         const struct exception_table_entry *entry;
 263         unsigned int *nip = (unsigned int *)regs->nip;
 264
 265         if (((msr & 0xffff0000) == 0 || (msr & (0x80000 | 0x40000)))
 266             && (entry = search_exception_tables(regs->nip)) != NULL) {
 267                 /*
 268                  * Check that it's a sync instruction, or somewhere
 269                  * in the twi; isync; nop sequence that inb/inw/inl uses.
 270                  * As the address is in the exception table
 271                  * we should be able to read the instr there.
 272                  * For the debug message, we look at the preceding
 273                  * load or store.
 274                  */
 275                 if (*nip == 0x60000000)         /* nop */
 276                         nip -= 2;
 277                 else if (*nip == 0x4c00012c)    /* isync */
 278                         --nip;
 279                 if (*nip == 0x7c0004ac || (*nip >> 26) == 3) {
 280                         /* sync or twi */
 281                         unsigned int rb;
 282
 283                         --nip;
 284                         rb = (*nip >> 11) & 0x1f;
 285                         printk(KERN_DEBUG "%s bad port %lx at %p\n",
 286                                (*nip & 0x100)? "OUT to": "IN from",
 287                                regs->gpr[rb] - _IO_BASE, nip);
 288                         regs->msr |= MSR_RI;
 289                         regs->nip = entry->fixup;
 290                         return 1;
 291                 }
 292         }
 293 #endif /* CONFIG_PPC_PMAC */
 294         return 0;
 295 }
 296
 297 #if defined(CONFIG_4xx) || defined(CONFIG_BOOKE)
 298 /* On 4xx, the reason for the machine check or program exception
 299    is in the ESR. */
 300 #define get_reason(regs)        ((regs)->dsisr)
 301 #ifndef CONFIG_FSL_BOOKE
 302 #define get_mc_reason(regs)     ((regs)->dsisr)
 303 #else
 304 #define get_mc_reason(regs)     (mfspr(SPRN_MCSR))
 305 #endif
 306 #define REASON_FP               ESR_FP
 307 #define REASON_ILLEGAL          (ESR_PIL | ESR_PUO)
 308 #define REASON_PRIVILEGED       ESR_PPR
 309 #define REASON_TRAP             ESR_PTR
 310
 311 /* single-step stuff */
 312 #define single_stepping(regs)   (current->thread.dbcr0 & DBCR0_IC)
 313 #define clear_single_step(regs) (current->thread.dbcr0 &= ~DBCR0_IC)
 314
 315 #else
 316 /* On non-4xx, the reason for the machine check or program
 317    exception is in the MSR. */
 318 #define get_reason(regs)        ((regs)->msr)
 319 #define get_mc_reason(regs)     ((regs)->msr)
 320 #define REASON_FP               0x100000
 321 #define REASON_ILLEGAL          0x80000
 322 #define REASON_PRIVILEGED       0x40000
 323 #define REASON_TRAP             0x20000
 324
 325 #define single_stepping(regs)   ((regs)->msr & MSR_SE)
 326 #define clear_single_step(regs) ((regs)->msr &= ~MSR_SE)
 327 #endif
 328
 329 /*
 330  * This is "fall-back" implementation for configurations
 331  * which don't provide platform-specific machine check info
 332  */
 333 void __attribute__ ((weak))
 334 platform_machine_check(struct pt_regs *regs)
 335 {
 336 }
 337
 338 void machine_check_exception(struct pt_regs *regs)
 339 {
 340 #ifdef CONFIG_PPC64
 341         int recover = 0;
 342
 343         /* See if any machine dependent calls */
 344         if (ppc_md.machine_check_exception)
 345                 recover = ppc_md.machine_check_exception(regs);
 346
 347         if (recover)
 348                 return;
 349 #else
 350         unsigned long reason = get_mc_reason(regs);
 351
 352         if (user_mode(regs)) {
 353                 regs->msr |= MSR_RI;
 354                 _exception(SIGBUS, regs, BUS_ADRERR, regs->nip);
 355                 return;
 356         }
 357
 358 #if defined(CONFIG_8xx) && defined(CONFIG_PCI)
 359         /* the qspan pci read routines can cause machine checks -- Cort */
 360         bad_page_fault(regs, regs->dar, SIGBUS);
 361         return;
 362 #endif
 363
 364         if (debugger_fault_handler(regs)) {
 365                 regs->msr |= MSR_RI;
 366                 return;
 367         }
 368
 369         if (check_io_access(regs))
 370                 return;
 371
 372 #if defined(CONFIG_4xx) && !defined(CONFIG_440A)
 373         if (reason & ESR_IMCP) {
 374                 printk("Instruction");
 375                 mtspr(SPRN_ESR, reason & ~ESR_IMCP);
 376         } else
 377                 printk("Data");
 378         printk(" machine check in kernel mode.\n");
 379 #elif defined(CONFIG_440A)
 380         printk("Machine check in kernel mode.\n");
 381         if (reason & ESR_IMCP){
 382                 printk("Instruction Synchronous Machine Check exception\n");
 383                 mtspr(SPRN_ESR, reason & ~ESR_IMCP);
 384         }
 385         else {
 386                 u32 mcsr = mfspr(SPRN_MCSR);
 387                 if (mcsr & MCSR_IB)
 388                         printk("Instruction Read PLB Error\n");
 389                 if (mcsr & MCSR_DRB)
 390                         printk("Data Read PLB Error\n");
 391                 if (mcsr & MCSR_DWB)
 392                         printk("Data Write PLB Error\n");
 393                 if (mcsr & MCSR_TLBP)
 394                         printk("TLB Parity Error\n");
 395                 if (mcsr & MCSR_ICP){
 396                         flush_instruction_cache();
 397                         printk("I-Cache Parity Error\n");
 398                 }
 399                 if (mcsr & MCSR_DCSP)
 400                         printk("D-Cache Search Parity Error\n");
 401                 if (mcsr & MCSR_DCFP)
 402                         printk("D-Cache Flush Parity Error\n");
 403                 if (mcsr & MCSR_IMPE)
 404                         printk("Machine Check exception is imprecise\n");
 405
 406                 /* Clear MCSR */
 407                 mtspr(SPRN_MCSR, mcsr);
 408         }
 409 #elif defined (CONFIG_E500)
 410         printk("Machine check in kernel mode.\n");
 411         printk("Caused by (from MCSR=%lx): ", reason);
 412
 413         if (reason & MCSR_MCP)
 414                 printk("Machine Check Signal\n");
 415         if (reason & MCSR_ICPERR)
 416                 printk("Instruction Cache Parity Error\n");
 417         if (reason & MCSR_DCP_PERR)
 418                 printk("Data Cache Push Parity Error\n");
 419         if (reason & MCSR_DCPERR)
 420                 printk("Data Cache Parity Error\n");
 421         if (reason & MCSR_GL_CI)
 422                 printk("Guarded Load or Cache-Inhibited stwcx.\n");
 423         if (reason & MCSR_BUS_IAERR)
 424                 printk("Bus - Instruction Address Error\n");
 425         if (reason & MCSR_BUS_RAERR)
 426                 printk("Bus - Read Address Error\n");
 427         if (reason & MCSR_BUS_WAERR)
 428                 printk("Bus - Write Address Error\n");
 429         if (reason & MCSR_BUS_IBERR)
 430                 printk("Bus - Instruction Data Error\n");
 431         if (reason & MCSR_BUS_RBERR)
 432                 printk("Bus - Read Data Bus Error\n");
 433         if (reason & MCSR_BUS_WBERR)
 434                 printk("Bus - Read Data Bus Error\n");
 435         if (reason & MCSR_BUS_IPERR)
 436                 printk("Bus - Instruction Parity Error\n");
 437         if (reason & MCSR_BUS_RPERR)
 438                 printk("Bus - Read Parity Error\n");
 439 #elif defined (CONFIG_E200)
 440         printk("Machine check in kernel mode.\n");
 441         printk("Caused by (from MCSR=%lx): ", reason);
 442
 443         if (reason & MCSR_MCP)
 444                 printk("Machine Check Signal\n");
 445         if (reason & MCSR_CP_PERR)
 446                 printk("Cache Push Parity Error\n");
 447         if (reason & MCSR_CPERR)
 448                 printk("Cache Parity Error\n");
 449         if (reason & MCSR_EXCP_ERR)
 450                 printk("ISI, ITLB, or Bus Error on first instruction fetch for an exception handler\n");
 451         if (reason & MCSR_BUS_IRERR)
 452                 printk("Bus - Read Bus Error on instruction fetch\n");
 453         if (reason & MCSR_BUS_DRERR)
 454                 printk("Bus - Read Bus Error on data load\n");
 455         if (reason & MCSR_BUS_WRERR)
 456                 printk("Bus - Write Bus Error on buffered store or cache line push\n");
 457 #else /* !CONFIG_4xx && !CONFIG_E500 && !CONFIG_E200 */
 458         printk("Machine check in kernel mode.\n");
 459         printk("Caused by (from SRR1=%lx): ", reason);
 460         switch (reason & 0x601F0000) {
 461         case 0x80000:
 462                 printk("Machine check signal\n");
 463                 break;
 464         case 0:         /* for 601 */
 465         case 0x40000:
 466         case 0x140000:  /* 7450 MSS error and TEA */
 467                 printk("Transfer error ack signal\n");
 468                 break;
 469         case 0x20000:
 470                 printk("Data parity error signal\n");
 471                 break;
 472         case 0x10000:
 473                 printk("Address parity error signal\n");
 474                 break;
 475         case 0x20000000:
 476                 printk("L1 Data Cache error\n");
 477                 break;
 478         case 0x40000000:
 479                 printk("L1 Instruction Cache error\n");
 480                 break;
 481         case 0x00100000:
 482                 printk("L2 data cache parity error\n");
 483                 break;
 484         default:
 485                 printk("Unknown values in msr\n");
 486         }
 487 #endif /* CONFIG_4xx */
 488
 489         /*
 490          * Optional platform-provided routine to print out
 491          * additional info, e.g. bus error registers.
 492          */
 493         platform_machine_check(regs);
 494 #endif /* CONFIG_PPC64 */
 495
 496         if (debugger_fault_handler(regs))
 497                 return;
 498         die("Machine check", regs, SIGBUS);
 499
 500         /* Must die if the interrupt is not recoverable */
 501         if (!(regs->msr & MSR_RI))
 502                 panic("Unrecoverable Machine check");
 503 }
 504
 505 void SMIException(struct pt_regs *regs)
 506 {
 507         die("System Management Interrupt", regs, SIGABRT);
 508 }
 509
 510 void unknown_exception(struct pt_regs *regs)
 511 {
 512         printk("Bad trap at PC: %lx, SR: %lx, vector=%lx\n",
 513                regs->nip, regs->msr, regs->trap);
 514
 515         _exception(SIGTRAP, regs, 0, 0);
 516 }
 517
 518 void instruction_breakpoint_exception(struct pt_regs *regs)
 519 {
 520         if (notify_die(DIE_IABR_MATCH, "iabr_match", regs, 5,
 521                                         5, SIGTRAP) == NOTIFY_STOP)
 522                 return;
 523         if (debugger_iabr_match(regs))
 524                 return;
 525         _exception(SIGTRAP, regs, TRAP_BRKPT, regs->nip);
 526 }
 527
 528 void RunModeException(struct pt_regs *regs)
 529 {
 530         _exception(SIGTRAP, regs, 0, 0);
 531 }
 532
 533 void __kprobes single_step_exception(struct pt_regs *regs)
 534 {
 535         regs->msr &= ~(MSR_SE | MSR_BE);  /* Turn off 'trace' bits */
 536
 537         if (notify_die(DIE_SSTEP, "single_step", regs, 5,
 538                                         5, SIGTRAP) == NOTIFY_STOP)
 539                 return;
 540         if (debugger_sstep(regs))
 541                 return;
 542
 543         _exception(SIGTRAP, regs, TRAP_TRACE, regs->nip);
 544 }
 545
 546 /*
 547  * After we have successfully emulated an instruction, we have to
 548  * check if the instruction was being single-stepped, and if so,
 549  * pretend we got a single-step exception.  This was pointed out
 550  * by Kumar Gala.  -- paulus
 551  */
 552 static void emulate_single_step(struct pt_regs *regs)
 553 {
 554         if (single_stepping(regs)) {
 555                 clear_single_step(regs);
 556                 _exception(SIGTRAP, regs, TRAP_TRACE, 0);
 557         }
 558 }
 559
 560 static void parse_fpe(struct pt_regs *regs)
 561 {
 562         int code = 0;
 563         unsigned long fpscr;
 564
 565         flush_fp_to_thread(current);
 566
 567         fpscr = current->thread.fpscr.val;
 568
 569         /* Invalid operation */
 570         if ((fpscr & FPSCR_VE) && (fpscr & FPSCR_VX))
 571                 code = FPE_FLTINV;
 572
 573         /* Overflow */
 574         else if ((fpscr & FPSCR_OE) && (fpscr & FPSCR_OX))
 575                 code = FPE_FLTOVF;
 576
 577         /* Underflow */
 578         else if ((fpscr & FPSCR_UE) && (fpscr & FPSCR_UX))
 579                 code = FPE_FLTUND;
 580
 581         /* Divide by zero */
 582         else if ((fpscr & FPSCR_ZE) && (fpscr & FPSCR_ZX))
 583                 code = FPE_FLTDIV;
 584
 585         /* Inexact result */
 586         else if ((fpscr & FPSCR_XE) && (fpscr & FPSCR_XX))
 587                 code = FPE_FLTRES;
 588
 589         _exception(SIGFPE, regs, code, regs->nip);
 590 }
 591
 592 /*
 593  * Illegal instruction emulation support.  Originally written to
 594  * provide the PVR to user applications using the mfspr rd, PVR.
 595  * Return non-zero if we can't emulate, or -EFAULT if the associated
 596  * memory access caused an access fault.  Return zero on success.
 597  *
 598  * There are a couple of ways to do this, either "decode" the instruction
 599  * or directly match lots of bits.  In this case, matching lots of
 600  * bits is faster and easier.
 601  *
 602  */
 603 #define INST_MFSPR_PVR          0x7c1f42a6
 604 #define INST_MFSPR_PVR_MASK     0xfc1fffff
 605
 606 #define INST_DCBA               0x7c0005ec
 607 #define INST_DCBA_MASK          0x7c0007fe
 608
 609 #define INST_MCRXR              0x7c000400
 610 #define INST_MCRXR_MASK         0x7c0007fe
 611
 612 #define INST_STRING             0x7c00042a
 613 #define INST_STRING_MASK        0x7c0007fe
 614 #define INST_STRING_GEN_MASK    0x7c00067e
 615 #define INST_LSWI               0x7c0004aa
 616 #define INST_LSWX               0x7c00042a
 617 #define INST_STSWI              0x7c0005aa
 618 #define INST_STSWX              0x7c00052a
 619
 620 static int emulate_string_inst(struct pt_regs *regs, u32 instword)
 621 {
 622         u8 rT = (instword >> 21) & 0x1f;
 623         u8 rA = (instword >> 16) & 0x1f;
 624         u8 NB_RB = (instword >> 11) & 0x1f;
 625         u32 num_bytes;
 626         unsigned long EA;
 627         int pos = 0;
 628
 629         /* Early out if we are an invalid form of lswx */
 630         if ((instword & INST_STRING_MASK) == INST_LSWX)
 631                 if ((rT == rA) || (rT == NB_RB))
 632                         return -EINVAL;
 633
 634         EA = (rA == 0) ? 0 : regs->gpr[rA];
 635
 636         switch (instword & INST_STRING_MASK) {
 637                 case INST_LSWX:
 638                 case INST_STSWX:
 639                         EA += NB_RB;
 640                         num_bytes = regs->xer & 0x7f;
 641                         break;
 642                 case INST_LSWI:
 643                 case INST_STSWI:
 644                         num_bytes = (NB_RB == 0) ? 32 : NB_RB;
 645                         break;
 646                 default:
 647                         return -EINVAL;
 648         }
 649
 650         while (num_bytes != 0)
 651         {
 652                 u8 val;
 653                 u32 shift = 8 * (3 - (pos & 0x3));
 654
 655                 switch ((instword & INST_STRING_MASK)) {
 656                         case INST_LSWX:
 657                         case INST_LSWI:
 658                                 if (get_user(val, (u8 __user *)EA))
 659                                         return -EFAULT;
 660                                 /* first time updating this reg,
 661                                  * zero it out */
 662                                 if (pos == 0)
 663                                         regs->gpr[rT] = 0;
 664                                 regs->gpr[rT] |= val << shift;
 665                                 break;
 666                         case INST_STSWI:
 667                         case INST_STSWX:
 668                                 val = regs->gpr[rT] >> shift;
 669                                 if (put_user(val, (u8 __user *)EA))
 670                                         return -EFAULT;
 671                                 break;
 672                 }
 673                 /* move EA to next address */
 674                 EA += 1;
 675                 num_bytes--;
 676
 677                 /* manage our position within the register */
 678                 if (++pos == 4) {
 679                         pos = 0;
 680                         if (++rT == 32)
 681                                 rT = 0;
 682                 }
 683         }
 684
 685         return 0;
 686 }
 687
 688 static int emulate_instruction(struct pt_regs *regs)
 689 {
 690         u32 instword;
 691         u32 rd;
 692
 693         if (!user_mode(regs))
 694                 return -EINVAL;
 695         CHECK_FULL_REGS(regs);
 696
 697         if (get_user(instword, (u32 __user *)(regs->nip)))
 698                 return -EFAULT;
 699
 700         /* Emulate the mfspr rD, PVR. */
 701         if ((instword & INST_MFSPR_PVR_MASK) == INST_MFSPR_PVR) {
 702                 rd = (instword >> 21) & 0x1f;
 703                 regs->gpr[rd] = mfspr(SPRN_PVR);
 704                 return 0;
 705         }
 706
 707         /* Emulating the dcba insn is just a no-op.  */
 708         if ((instword & INST_DCBA_MASK) == INST_DCBA)
 709                 return 0;
 710
 711         /* Emulate the mcrxr insn.  */
 712         if ((instword & INST_MCRXR_MASK) == INST_MCRXR) {
 713                 int shift = (instword >> 21) & 0x1c;
 714                 unsigned long msk = 0xf0000000UL >> shift;
 715
 716                 regs->ccr = (regs->ccr & ~msk) | ((regs->xer >> shift) & msk);
 717                 regs->xer &= ~0xf0000000UL;
 718                 return 0;
 719         }
 720
 721         /* Emulate load/store string insn. */
 722         if ((instword & INST_STRING_GEN_MASK) == INST_STRING)
 723                 return emulate_string_inst(regs, instword);
 724
 725         return -EINVAL;
 726 }
 727
 728 /*
 729  * Look through the list of trap instructions that are used for BUG(),
 730  * BUG_ON() and WARN_ON() and see if we hit one.  At this point we know
 731  * that the exception was caused by a trap instruction of some kind.
 732  * Returns 1 if we should continue (i.e. it was a WARN_ON) or 0
 733  * otherwise.
 734  */
 735 extern struct bug_entry __start___bug_table[], __stop___bug_table[];
 736
 737 #ifndef CONFIG_MODULES
 738 #define module_find_bug(x)      NULL
 739 #endif
 740
 741 struct bug_entry *find_bug(unsigned long bugaddr)
 742 {
 743         struct bug_entry *bug;
 744
 745         for (bug = __start___bug_table; bug < __stop___bug_table; ++bug)
 746                 if (bugaddr == bug->bug_addr)
 747                         return bug;
 748         return module_find_bug(bugaddr);
 749 }
 750
 751 static int check_bug_trap(struct pt_regs *regs)
 752 {
 753         struct bug_entry *bug;
 754         unsigned long addr;
 755
 756         if (regs->msr & MSR_PR)
 757                 return 0;       /* not in kernel */
 758         addr = regs->nip;       /* address of trap instruction */
 759         if (addr < PAGE_OFFSET)
 760                 return 0;
 761         bug = find_bug(regs->nip);
 762         if (bug == NULL)
 763                 return 0;
 764         if (bug->line & BUG_WARNING_TRAP) {
 765                 /* this is a WARN_ON rather than BUG/BUG_ON */
 766                 printk(KERN_ERR "Badness in %s at %s:%ld\n",
 767                        bug->function, bug->file,
 768                        bug->line & ~BUG_WARNING_TRAP);
 769                 dump_stack();
 770                 return 1;
 771         }
 772         printk(KERN_CRIT "kernel BUG in %s at %s:%ld!\n",
 773                bug->function, bug->file, bug->line);
 774
 775         return 0;
 776 }
 777
 778 void __kprobes program_check_exception(struct pt_regs *regs)
 779 {
 780         unsigned int reason = get_reason(regs);
 781         extern int do_mathemu(struct pt_regs *regs);
 782
 783 #ifdef CONFIG_MATH_EMULATION
 784         /* (reason & REASON_ILLEGAL) would be the obvious thing here,
 785          * but there seems to be a hardware bug on the 405GP (RevD)
 786          * that means ESR is sometimes set incorrectly - either to
 787          * ESR_DST (!?) or 0.  In the process of chasing this with the
 788          * hardware people - not sure if it can happen on any illegal
 789          * instruction or only on FP instructions, whether there is a
 790          * pattern to occurences etc. -dgibson 31/Mar/2003 */
 791         if (!(reason & REASON_TRAP) && do_mathemu(regs) == 0) {
 792                 emulate_single_step(regs);
 793                 return;
 794         }
 795 #endif /* CONFIG_MATH_EMULATION */
 796
 797         if (reason & REASON_FP) {
 798                 /* IEEE FP exception */
 799                 parse_fpe(regs);
 800                 return;
 801         }
 802         if (reason & REASON_TRAP) {
 803                 /* trap exception */
 804                 if (notify_die(DIE_BPT, "breakpoint", regs, 5, 5, SIGTRAP)
 805                                 == NOTIFY_STOP)
 806                         return;
 807                 if (debugger_bpt(regs))
 808                         return;
 809                 if (check_bug_trap(regs)) {
 810                         regs->nip += 4;
 811                         return;
 812                 }
 813                 _exception(SIGTRAP, regs, TRAP_BRKPT, regs->nip);
 814                 return;
 815         }
 816
 817         local_irq_enable();
 818
 819         /* Try to emulate it if we should. */
 820         if (reason & (REASON_ILLEGAL | REASON_PRIVILEGED)) {
 821                 switch (emulate_instruction(regs)) {
 822                 case 0:
 823                         regs->nip += 4;
 824                         emulate_single_step(regs);
 825                         return;
 826                 case -EFAULT:
 827                         _exception(SIGSEGV, regs, SEGV_MAPERR, regs->nip);
 828                         return;
 829                 }
 830         }
 831
 832         if (reason & REASON_PRIVILEGED)
 833                 _exception(SIGILL, regs, ILL_PRVOPC, regs->nip);
 834         else
 835                 _exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
 836 }
 837
 838 void alignment_exception(struct pt_regs *regs)
 839 {
 840         int fixed;
 841
 842         fixed = fix_alignment(regs);
 843
 844         if (fixed == 1) {
 845                 regs->nip += 4; /* skip over emulated instruction */
 846                 emulate_single_step(regs);
 847                 return;
 848         }
 849
 850         /* Operand address was bad */
 851         if (fixed == -EFAULT) {
 852                 if (user_mode(regs))
 853                         _exception(SIGSEGV, regs, SEGV_ACCERR, regs->dar);
 854                 else
 855                         /* Search exception table */
 856                         bad_page_fault(regs, regs->dar, SIGSEGV);
 857                 return;
 858         }
 859         _exception(SIGBUS, regs, BUS_ADRALN, regs->dar);
 860 }
 861
 862 void StackOverflow(struct pt_regs *regs)
 863 {
 864         printk(KERN_CRIT "Kernel stack overflow in process %p, r1=%lx\n",
 865                current, regs->gpr[1]);
 866         debugger(regs);
 867         show_regs(regs);
 868         panic("kernel stack overflow");
 869 }
 870
 871 void nonrecoverable_exception(struct pt_regs *regs)
 872 {
 873         printk(KERN_ERR "Non-recoverable exception at PC=%lx MSR=%lx\n",
 874                regs->nip, regs->msr);
 875         debugger(regs);
 876         die("nonrecoverable exception", regs, SIGKILL);
 877 }
 878
 879 void trace_syscall(struct pt_regs *regs)
 880 {
 881         printk("Task: %p(%d), PC: %08lX/%08lX, Syscall: %3ld, Result: %s%ld    %s\n",
 882                current, current->pid, regs->nip, regs->link, regs->gpr[0],
 883                regs->ccr&0x10000000?"Error=":"", regs->gpr[3], print_tainted());
 884 }
 885
 886 void kernel_fp_unavailable_exception(struct pt_regs *regs)
 887 {
 888         printk(KERN_EMERG "Unrecoverable FP Unavailable Exception "
 889                           "%lx at %lx\n", regs->trap, regs->nip);
 890         die("Unrecoverable FP Unavailable Exception", regs, SIGABRT);
 891 }
 892
 893 void altivec_unavailable_exception(struct pt_regs *regs)
 894 {
 895 #if !defined(CONFIG_ALTIVEC)
 896         if (user_mode(regs)) {
 897                 /* A user program has executed an altivec instruction,
 898                    but this kernel doesn't support altivec. */
 899                 _exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
 900                 return;
 901         }
 902 #endif
 903         printk(KERN_EMERG "Unrecoverable VMX/Altivec Unavailable Exception "
 904                         "%lx at %lx\n", regs->trap, regs->nip);
 905         die("Unrecoverable VMX/Altivec Unavailable Exception", regs, SIGABRT);
 906 }
 907
 908 void performance_monitor_exception(struct pt_regs *regs)
 909 {
 910         perf_irq(regs);
 911 }
 912
 913 #ifdef CONFIG_8xx
 914 void SoftwareEmulation(struct pt_regs *regs)
 915 {
 916         extern int do_mathemu(struct pt_regs *);
 917         extern int Soft_emulate_8xx(struct pt_regs *);
 918         int errcode;
 919
 920         CHECK_FULL_REGS(regs);
 921
 922         if (!user_mode(regs)) {
 923                 debugger(regs);
 924                 die("Kernel Mode Software FPU Emulation", regs, SIGFPE);
 925         }
 926
 927 #ifdef CONFIG_MATH_EMULATION
 928         errcode = do_mathemu(regs);
 929 #else
 930         errcode = Soft_emulate_8xx(regs);
 931 #endif
 932         if (errcode) {
 933                 if (errcode > 0)
 934                         _exception(SIGFPE, regs, 0, 0);
 935                 else if (errcode == -EFAULT)
 936                         _exception(SIGSEGV, regs, 0, 0);
 937                 else
 938                         _exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
 939         } else
 940                 emulate_single_step(regs);
 941 }
 942 #endif /* CONFIG_8xx */
 943
 944 #if defined(CONFIG_40x) || defined(CONFIG_BOOKE)
 945
 946 void DebugException(struct pt_regs *regs, unsigned long debug_status)
 947 {
 948         if (debug_status & DBSR_IC) {   /* instruction completion */
 949                 regs->msr &= ~MSR_DE;
 950                 if (user_mode(regs)) {
 951                         current->thread.dbcr0 &= ~DBCR0_IC;
 952                 } else {
 953                         /* Disable instruction completion */
 954                         mtspr(SPRN_DBCR0, mfspr(SPRN_DBCR0) & ~DBCR0_IC);
 955                         /* Clear the instruction completion event */
 956                         mtspr(SPRN_DBSR, DBSR_IC);
 957                         if (debugger_sstep(regs))
 958                                 return;
 959                 }
 960                 _exception(SIGTRAP, regs, TRAP_TRACE, 0);
 961         }
 962 }
 963 #endif /* CONFIG_4xx || CONFIG_BOOKE */
 964
 965 #if !defined(CONFIG_TAU_INT)
 966 void TAUException(struct pt_regs *regs)
 967 {
 968         printk("TAU trap at PC: %lx, MSR: %lx, vector=%lx    %s\n",
 969                regs->nip, regs->msr, regs->trap, print_tainted());
 970 }
 971 #endif /* CONFIG_INT_TAU */
 972
 973 #ifdef CONFIG_ALTIVEC
 974 void altivec_assist_exception(struct pt_regs *regs)
 975 {
 976         int err;
 977
 978         if (!user_mode(regs)) {
 979                 printk(KERN_EMERG "VMX/Altivec assist exception in kernel mode"
 980                        " at %lx\n", regs->nip);
 981                 die("Kernel VMX/Altivec assist exception", regs, SIGILL);
 982         }
 983
 984         flush_altivec_to_thread(current);
 985
 986         err = emulate_altivec(regs);
 987         if (err == 0) {
 988                 regs->nip += 4;         /* skip emulated instruction */
 989                 emulate_single_step(regs);
 990                 return;
 991         }
 992
 993         if (err == -EFAULT) {
 994                 /* got an error reading the instruction */
 995                 _exception(SIGSEGV, regs, SEGV_ACCERR, regs->nip);
 996         } else {
 997                 /* didn't recognize the instruction */
 998                 /* XXX quick hack for now: set the non-Java bit in the VSCR */
 999                 if (printk_ratelimit())
1000                         printk(KERN_ERR "Unrecognized altivec instruction "
1001                                "in %s at %lx\n", current->comm, regs->nip);
1002                 current->thread.vscr.u[3] |= 0x10000;
1003         }
1004 }
1005 #endif /* CONFIG_ALTIVEC */
1006
1007 #ifdef CONFIG_FSL_BOOKE
1008 void CacheLockingException(struct pt_regs *regs, unsigned long address,
1009                            unsigned long error_code)
1010 {
1011         /* We treat cache locking instructions from the user
1012          * as priv ops, in the future we could try to do
1013          * something smarter
1014          */
1015         if (error_code & (ESR_DLK|ESR_ILK))
1016                 _exception(SIGILL, regs, ILL_PRVOPC, regs->nip);
1017         return;
1018 }
1019 #endif /* CONFIG_FSL_BOOKE */
1020
1021 #ifdef CONFIG_SPE
1022 void SPEFloatingPointException(struct pt_regs *regs)
1023 {
1024         unsigned long spefscr;
1025         int fpexc_mode;
1026         int code = 0;
1027
1028         spefscr = current->thread.spefscr;
1029         fpexc_mode = current->thread.fpexc_mode;
1030
1031         /* Hardware does not neccessarily set sticky
1032          * underflow/overflow/invalid flags */
1033         if ((spefscr & SPEFSCR_FOVF) && (fpexc_mode & PR_FP_EXC_OVF)) {
1034                 code = FPE_FLTOVF;
1035                 spefscr |= SPEFSCR_FOVFS;
1036         }
1037         else if ((spefscr & SPEFSCR_FUNF) && (fpexc_mode & PR_FP_EXC_UND)) {
1038                 code = FPE_FLTUND;
1039                 spefscr |= SPEFSCR_FUNFS;
1040         }
1041         else if ((spefscr & SPEFSCR_FDBZ) && (fpexc_mode & PR_FP_EXC_DIV))
1042                 code = FPE_FLTDIV;
1043         else if ((spefscr & SPEFSCR_FINV) && (fpexc_mode & PR_FP_EXC_INV)) {
1044                 code = FPE_FLTINV;
1045                 spefscr |= SPEFSCR_FINVS;
1046         }
1047         else if ((spefscr & (SPEFSCR_FG | SPEFSCR_FX)) && (fpexc_mode & PR_FP_EXC_RES))
1048                 code = FPE_FLTRES;
1049
1050         current->thread.spefscr = spefscr;
1051
1052         _exception(SIGFPE, regs, code, regs->nip);
1053         return;
1054 }
1055 #endif
1056
1057 /*
1058  * We enter here if we get an unrecoverable exception, that is, one
1059  * that happened at a point where the RI (recoverable interrupt) bit
1060  * in the MSR is 0.  This indicates that SRR0/1 are live, and that
1061  * we therefore lost state by taking this exception.
1062  */
1063 void unrecoverable_exception(struct pt_regs *regs)
1064 {
1065         printk(KERN_EMERG "Unrecoverable exception %lx at %lx\n",
1066                regs->trap, regs->nip);
1067         die("Unrecoverable exception", regs, SIGABRT);
1068 }
1069
1070 #ifdef CONFIG_BOOKE_WDT
1071 /*
1072  * Default handler for a Watchdog exception,
1073  * spins until a reboot occurs
1074  */
1075 void __attribute__ ((weak)) WatchdogHandler(struct pt_regs *regs)
1076 {
1077         /* Generic WatchdogHandler, implement your own */
1078         mtspr(SPRN_TCR, mfspr(SPRN_TCR)&(~TCR_WIE));
1079         return;
1080 }
1081
1082 void WatchdogException(struct pt_regs *regs)
1083 {
1084         printk (KERN_EMERG "PowerPC Book-E Watchdog Exception\n");
1085         WatchdogHandler(regs);
1086 }
1087 #endif
1088
1089 /*
1090  * We enter here if we discover during exception entry that we are
1091  * running in supervisor mode with a userspace value in the stack pointer.
1092  */
1093 void kernel_bad_stack(struct pt_regs *regs)
1094 {
1095         printk(KERN_EMERG "Bad kernel stack pointer %lx at %lx\n",
1096                regs->gpr[1], regs->nip);
1097         die("Bad kernel stack pointer", regs, SIGABRT);
1098 }
1099
1100 void __init trap_init(void)
1101 {
1102 }