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