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 #include <linux/bug.h>
  36 #include <linux/kdebug.h>
  37
  38 #include <asm/pgtable.h>
  39 #include <asm/uaccess.h>
  40 #include <asm/system.h>
  41 #include <asm/io.h>
  42 #include <asm/machdep.h>
  43 #include <asm/rtas.h>
  44 #include <asm/pmc.h>
  45 #ifdef CONFIG_PPC32
  46 #include <asm/reg.h>
  47 #endif
  48 #ifdef CONFIG_PMAC_BACKLIGHT
  49 #include <asm/backlight.h>
  50 #endif
  51 #ifdef CONFIG_PPC64
  52 #include <asm/firmware.h>
  53 #include <asm/processor.h>
  54 #endif
  55 #include <asm/kexec.h>
  56
  57 #if defined(CONFIG_DEBUGGER) || defined(CONFIG_KEXEC)
  58 int (*__debugger)(struct pt_regs *regs);
  59 int (*__debugger_ipi)(struct pt_regs *regs);
  60 int (*__debugger_bpt)(struct pt_regs *regs);
  61 int (*__debugger_sstep)(struct pt_regs *regs);
  62 int (*__debugger_iabr_match)(struct pt_regs *regs);
  63 int (*__debugger_dabr_match)(struct pt_regs *regs);
  64 int (*__debugger_fault_handler)(struct pt_regs *regs);
  65
  66 EXPORT_SYMBOL(__debugger);
  67 EXPORT_SYMBOL(__debugger_ipi);
  68 EXPORT_SYMBOL(__debugger_bpt);
  69 EXPORT_SYMBOL(__debugger_sstep);
  70 EXPORT_SYMBOL(__debugger_iabr_match);
  71 EXPORT_SYMBOL(__debugger_dabr_match);
  72 EXPORT_SYMBOL(__debugger_fault_handler);
  73 #endif
  74
  75 /*
  76  * Trap & Exception support
  77  */
  78
  79 #ifdef CONFIG_PMAC_BACKLIGHT
  80 static void pmac_backlight_unblank(void)
  81 {
  82         mutex_lock(&pmac_backlight_mutex);
  83         if (pmac_backlight) {
  84                 struct backlight_properties *props;
  85
  86                 props = &pmac_backlight->props;
  87                 props->brightness = props->max_brightness;
  88                 props->power = FB_BLANK_UNBLANK;
  89                 backlight_update_status(pmac_backlight);
  90         }
  91         mutex_unlock(&pmac_backlight_mutex);
  92 }
  93 #else
  94 static inline void pmac_backlight_unblank(void) { }
  95 #endif
  96
  97 int die(const char *str, struct pt_regs *regs, long err)
  98 {
  99         static struct {
 100                 spinlock_t lock;
 101                 u32 lock_owner;
 102                 int lock_owner_depth;
 103         } die = {
 104                 .lock =                 __SPIN_LOCK_UNLOCKED(die.lock),
 105                 .lock_owner =           -1,
 106                 .lock_owner_depth =     0
 107         };
 108         static int die_counter;
 109         unsigned long flags;
 110
 111         if (debugger(regs))
 112                 return 1;
 113
 114         oops_enter();
 115
 116         if (die.lock_owner != raw_smp_processor_id()) {
 117                 console_verbose();
 118                 spin_lock_irqsave(&die.lock, flags);
 119                 die.lock_owner = smp_processor_id();
 120                 die.lock_owner_depth = 0;
 121                 bust_spinlocks(1);
 122                 if (machine_is(powermac))
 123                         pmac_backlight_unblank();
 124         } else {
 125                 local_save_flags(flags);
 126         }
 127
 128         if (++die.lock_owner_depth < 3) {
 129                 printk("Oops: %s, sig: %ld [#%d]\n", str, err, ++die_counter);
 130 #ifdef CONFIG_PREEMPT
 131                 printk("PREEMPT ");
 132 #endif
 133 #ifdef CONFIG_SMP
 134                 printk("SMP NR_CPUS=%d ", NR_CPUS);
 135 #endif
 136 #ifdef CONFIG_DEBUG_PAGEALLOC
 137                 printk("DEBUG_PAGEALLOC ");
 138 #endif
 139 #ifdef CONFIG_NUMA
 140                 printk("NUMA ");
 141 #endif
 142                 printk("%s\n", ppc_md.name ? ppc_md.name : "");
 143
 144                 print_modules();
 145                 show_regs(regs);
 146         } else {
 147                 printk("Recursive die() failure, output suppressed\n");
 148         }
 149
 150         bust_spinlocks(0);
 151         die.lock_owner = -1;
 152         add_taint(TAINT_DIE);
 153         spin_unlock_irqrestore(&die.lock, flags);
 154
 155         if (kexec_should_crash(current) ||
 156                 kexec_sr_activated(smp_processor_id()))
 157                 crash_kexec(regs);
 158         crash_kexec_secondary(regs);
 159
 160         if (in_interrupt())
 161                 panic("Fatal exception in interrupt");
 162
 163         if (panic_on_oops)
 164                 panic("Fatal exception");
 165
 166         oops_exit();
 167         do_exit(err);
 168
 169         return 0;
 170 }
 171
 172 void _exception(int signr, struct pt_regs *regs, int code, unsigned long addr)
 173 {
 174         siginfo_t info;
 175         const char fmt32[] = KERN_INFO "%s[%d]: unhandled signal %d " \
 176                         "at %08lx nip %08lx lr %08lx code %x\n";
 177         const char fmt64[] = KERN_INFO "%s[%d]: unhandled signal %d " \
 178                         "at %016lx nip %016lx lr %016lx code %x\n";
 179
 180         if (!user_mode(regs)) {
 181                 if (die("Exception in kernel mode", regs, signr))
 182                         return;
 183         } else if (show_unhandled_signals &&
 184                     unhandled_signal(current, signr) &&
 185                     printk_ratelimit()) {
 186                         printk(regs->msr & MSR_SF ? fmt64 : fmt32,
 187                                 current->comm, current->pid, signr,
 188                                 addr, regs->nip, regs->link, code);
 189                 }
 190
 191         memset(&info, 0, sizeof(info));
 192         info.si_signo = signr;
 193         info.si_code = code;
 194         info.si_addr = (void __user *) addr;
 195         force_sig_info(signr, &info, current);
 196
 197         /*
 198          * Init gets no signals that it doesn't have a handler for.
 199          * That's all very well, but if it has caused a synchronous
 200          * exception and we ignore the resulting signal, it will just
 201          * generate the same exception over and over again and we get
 202          * nowhere.  Better to kill it and let the kernel panic.
 203          */
 204         if (is_global_init(current)) {
 205                 __sighandler_t handler;
 206
 207                 spin_lock_irq(&current->sighand->siglock);
 208                 handler = current->sighand->action[signr-1].sa.sa_handler;
 209                 spin_unlock_irq(&current->sighand->siglock);
 210                 if (handler == SIG_DFL) {
 211                         /* init has generated a synchronous exception
 212                            and it doesn't have a handler for the signal */
 213                         printk(KERN_CRIT "init has generated signal %d "
 214                                "but has no handler for it\n", signr);
 215                         do_exit(signr);
 216                 }
 217         }
 218 }
 219
 220 #ifdef CONFIG_PPC64
 221 void system_reset_exception(struct pt_regs *regs)
 222 {
 223         /* See if any machine dependent calls */
 224         if (ppc_md.system_reset_exception) {
 225                 if (ppc_md.system_reset_exception(regs))
 226                         return;
 227         }
 228
 229 #ifdef CONFIG_KEXEC
 230         cpu_set(smp_processor_id(), cpus_in_sr);
 231 #endif
 232
 233         die("System Reset", regs, SIGABRT);
 234
 235         /*
 236          * Some CPUs when released from the debugger will execute this path.
 237          * These CPUs entered the debugger via a soft-reset. If the CPU was
 238          * hung before entering the debugger it will return to the hung
 239          * state when exiting this function.  This causes a problem in
 240          * kdump since the hung CPU(s) will not respond to the IPI sent
 241          * from kdump. To prevent the problem we call crash_kexec_secondary()
 242          * here. If a kdump had not been initiated or we exit the debugger
 243          * with the "exit and recover" command (x) crash_kexec_secondary()
 244          * will return after 5ms and the CPU returns to its previous state.
 245          */
 246         crash_kexec_secondary(regs);
 247
 248         /* Must die if the interrupt is not recoverable */
 249         if (!(regs->msr & MSR_RI))
 250                 panic("Unrecoverable System Reset");
 251
 252         /* What should we do here? We could issue a shutdown or hard reset. */
 253 }
 254 #endif
 255
 256 /*
 257  * I/O accesses can cause machine checks on powermacs.
 258  * Check if the NIP corresponds to the address of a sync
 259  * instruction for which there is an entry in the exception
 260  * table.
 261  * Note that the 601 only takes a machine check on TEA
 262  * (transfer error ack) signal assertion, and does not
 263  * set any of the top 16 bits of SRR1.
 264  *  -- paulus.
 265  */
 266 static inline int check_io_access(struct pt_regs *regs)
 267 {
 268 #ifdef CONFIG_PPC32
 269         unsigned long msr = regs->msr;
 270         const struct exception_table_entry *entry;
 271         unsigned int *nip = (unsigned int *)regs->nip;
 272
 273         if (((msr & 0xffff0000) == 0 || (msr & (0x80000 | 0x40000)))
 274             && (entry = search_exception_tables(regs->nip)) != NULL) {
 275                 /*
 276                  * Check that it's a sync instruction, or somewhere
 277                  * in the twi; isync; nop sequence that inb/inw/inl uses.
 278                  * As the address is in the exception table
 279                  * we should be able to read the instr there.
 280                  * For the debug message, we look at the preceding
 281                  * load or store.
 282                  */
 283                 if (*nip == 0x60000000)         /* nop */
 284                         nip -= 2;
 285                 else if (*nip == 0x4c00012c)    /* isync */
 286                         --nip;
 287                 if (*nip == 0x7c0004ac || (*nip >> 26) == 3) {
 288                         /* sync or twi */
 289                         unsigned int rb;
 290
 291                         --nip;
 292                         rb = (*nip >> 11) & 0x1f;
 293                         printk(KERN_DEBUG "%s bad port %lx at %p\n",
 294                                (*nip & 0x100)? "OUT to": "IN from",
 295                                regs->gpr[rb] - _IO_BASE, nip);
 296                         regs->msr |= MSR_RI;
 297                         regs->nip = entry->fixup;
 298                         return 1;
 299                 }
 300         }
 301 #endif /* CONFIG_PPC32 */
 302         return 0;
 303 }
 304
 305 #if defined(CONFIG_4xx) || defined(CONFIG_BOOKE)
 306 /* On 4xx, the reason for the machine check or program exception
 307    is in the ESR. */
 308 #define get_reason(regs)        ((regs)->dsisr)
 309 #ifndef CONFIG_FSL_BOOKE
 310 #define get_mc_reason(regs)     ((regs)->dsisr)
 311 #else
 312 #define get_mc_reason(regs)     (mfspr(SPRN_MCSR) & MCSR_MASK)
 313 #endif
 314 #define REASON_FP               ESR_FP
 315 #define REASON_ILLEGAL          (ESR_PIL | ESR_PUO)
 316 #define REASON_PRIVILEGED       ESR_PPR
 317 #define REASON_TRAP             ESR_PTR
 318
 319 /* single-step stuff */
 320 #define single_stepping(regs)   (current->thread.dbcr0 & DBCR0_IC)
 321 #define clear_single_step(regs) (current->thread.dbcr0 &= ~DBCR0_IC)
 322
 323 #else
 324 /* On non-4xx, the reason for the machine check or program
 325    exception is in the MSR. */
 326 #define get_reason(regs)        ((regs)->msr)
 327 #define get_mc_reason(regs)     ((regs)->msr)
 328 #define REASON_FP               0x100000
 329 #define REASON_ILLEGAL          0x80000
 330 #define REASON_PRIVILEGED       0x40000
 331 #define REASON_TRAP             0x20000
 332
 333 #define single_stepping(regs)   ((regs)->msr & MSR_SE)
 334 #define clear_single_step(regs) ((regs)->msr &= ~MSR_SE)
 335 #endif
 336
 337 #if defined(CONFIG_4xx)
 338 int machine_check_4xx(struct pt_regs *regs)
 339 {
 340         unsigned long reason = get_mc_reason(regs);
 341
 342         if (reason & ESR_IMCP) {
 343                 printk("Instruction");
 344                 mtspr(SPRN_ESR, reason & ~ESR_IMCP);
 345         } else
 346                 printk("Data");
 347         printk(" machine check in kernel mode.\n");
 348
 349         return 0;
 350 }
 351
 352 int machine_check_440A(struct pt_regs *regs)
 353 {
 354         unsigned long reason = get_mc_reason(regs);
 355
 356         printk("Machine check in kernel mode.\n");
 357         if (reason & ESR_IMCP){
 358                 printk("Instruction Synchronous Machine Check exception\n");
 359                 mtspr(SPRN_ESR, reason & ~ESR_IMCP);
 360         }
 361         else {
 362                 u32 mcsr = mfspr(SPRN_MCSR);
 363                 if (mcsr & MCSR_IB)
 364                         printk("Instruction Read PLB Error\n");
 365                 if (mcsr & MCSR_DRB)
 366                         printk("Data Read PLB Error\n");
 367                 if (mcsr & MCSR_DWB)
 368                         printk("Data Write PLB Error\n");
 369                 if (mcsr & MCSR_TLBP)
 370                         printk("TLB Parity Error\n");
 371                 if (mcsr & MCSR_ICP){
 372                         flush_instruction_cache();
 373                         printk("I-Cache Parity Error\n");
 374                 }
 375                 if (mcsr & MCSR_DCSP)
 376                         printk("D-Cache Search Parity Error\n");
 377                 if (mcsr & MCSR_DCFP)
 378                         printk("D-Cache Flush Parity Error\n");
 379                 if (mcsr & MCSR_IMPE)
 380                         printk("Machine Check exception is imprecise\n");
 381
 382                 /* Clear MCSR */
 383                 mtspr(SPRN_MCSR, mcsr);
 384         }
 385         return 0;
 386 }
 387 #elif defined(CONFIG_E500)
 388 int machine_check_e500(struct pt_regs *regs)
 389 {
 390         unsigned long reason = get_mc_reason(regs);
 391
 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_BUS_IAERR)
 404                 printk("Bus - Instruction Address Error\n");
 405         if (reason & MCSR_BUS_RAERR)
 406                 printk("Bus - Read Address Error\n");
 407         if (reason & MCSR_BUS_WAERR)
 408                 printk("Bus - Write Address Error\n");
 409         if (reason & MCSR_BUS_IBERR)
 410                 printk("Bus - Instruction Data Error\n");
 411         if (reason & MCSR_BUS_RBERR)
 412                 printk("Bus - Read Data Bus Error\n");
 413         if (reason & MCSR_BUS_WBERR)
 414                 printk("Bus - Read Data Bus Error\n");
 415         if (reason & MCSR_BUS_IPERR)
 416                 printk("Bus - Instruction Parity Error\n");
 417         if (reason & MCSR_BUS_RPERR)
 418                 printk("Bus - Read Parity Error\n");
 419
 420         return 0;
 421 }
 422 #elif defined(CONFIG_E200)
 423 int machine_check_e200(struct pt_regs *regs)
 424 {
 425         unsigned long reason = get_mc_reason(regs);
 426
 427         printk("Machine check in kernel mode.\n");
 428         printk("Caused by (from MCSR=%lx): ", reason);
 429
 430         if (reason & MCSR_MCP)
 431                 printk("Machine Check Signal\n");
 432         if (reason & MCSR_CP_PERR)
 433                 printk("Cache Push Parity Error\n");
 434         if (reason & MCSR_CPERR)
 435                 printk("Cache Parity Error\n");
 436         if (reason & MCSR_EXCP_ERR)
 437                 printk("ISI, ITLB, or Bus Error on first instruction fetch for an exception handler\n");
 438         if (reason & MCSR_BUS_IRERR)
 439                 printk("Bus - Read Bus Error on instruction fetch\n");
 440         if (reason & MCSR_BUS_DRERR)
 441                 printk("Bus - Read Bus Error on data load\n");
 442         if (reason & MCSR_BUS_WRERR)
 443                 printk("Bus - Write Bus Error on buffered store or cache line push\n");
 444
 445         return 0;
 446 }
 447 #else
 448 int machine_check_generic(struct pt_regs *regs)
 449 {
 450         unsigned long reason = get_mc_reason(regs);
 451
 452         printk("Machine check in kernel mode.\n");
 453         printk("Caused by (from SRR1=%lx): ", reason);
 454         switch (reason & 0x601F0000) {
 455         case 0x80000:
 456                 printk("Machine check signal\n");
 457                 break;
 458         case 0:         /* for 601 */
 459         case 0x40000:
 460         case 0x140000:  /* 7450 MSS error and TEA */
 461                 printk("Transfer error ack signal\n");
 462                 break;
 463         case 0x20000:
 464                 printk("Data parity error signal\n");
 465                 break;
 466         case 0x10000:
 467                 printk("Address parity error signal\n");
 468                 break;
 469         case 0x20000000:
 470                 printk("L1 Data Cache error\n");
 471                 break;
 472         case 0x40000000:
 473                 printk("L1 Instruction Cache error\n");
 474                 break;
 475         case 0x00100000:
 476                 printk("L2 data cache parity error\n");
 477                 break;
 478         default:
 479                 printk("Unknown values in msr\n");
 480         }
 481         return 0;
 482 }
 483 #endif /* everything else */
 484
 485 void machine_check_exception(struct pt_regs *regs)
 486 {
 487         int recover = 0;
 488
 489         /* See if any machine dependent calls. In theory, we would want
 490          * to call the CPU first, and call the ppc_md. one if the CPU
 491          * one returns a positive number. However there is existing code
 492          * that assumes the board gets a first chance, so let's keep it
 493          * that way for now and fix things later. --BenH.
 494          */
 495         if (ppc_md.machine_check_exception)
 496                 recover = ppc_md.machine_check_exception(regs);
 497         else if (cur_cpu_spec->machine_check)
 498                 recover = cur_cpu_spec->machine_check(regs);
 499
 500         if (recover > 0)
 501                 return;
 502
 503         if (user_mode(regs)) {
 504                 regs->msr |= MSR_RI;
 505                 _exception(SIGBUS, regs, BUS_ADRERR, regs->nip);
 506                 return;
 507         }
 508
 509 #if defined(CONFIG_8xx) && defined(CONFIG_PCI)
 510         /* the qspan pci read routines can cause machine checks -- Cort
 511          *
 512          * yuck !!! that totally needs to go away ! There are better ways
 513          * to deal with that than having a wart in the mcheck handler.
 514          * -- BenH
 515          */
 516         bad_page_fault(regs, regs->dar, SIGBUS);
 517         return;
 518 #endif
 519
 520         if (debugger_fault_handler(regs)) {
 521                 regs->msr |= MSR_RI;
 522                 return;
 523         }
 524
 525         if (check_io_access(regs))
 526                 return;
 527
 528         if (debugger_fault_handler(regs))
 529                 return;
 530         die("Machine check", regs, SIGBUS);
 531
 532         /* Must die if the interrupt is not recoverable */
 533         if (!(regs->msr & MSR_RI))
 534                 panic("Unrecoverable Machine check");
 535 }
 536
 537 void SMIException(struct pt_regs *regs)
 538 {
 539         die("System Management Interrupt", regs, SIGABRT);
 540 }
 541
 542 void unknown_exception(struct pt_regs *regs)
 543 {
 544         printk("Bad trap at PC: %lx, SR: %lx, vector=%lx\n",
 545                regs->nip, regs->msr, regs->trap);
 546
 547         _exception(SIGTRAP, regs, 0, 0);
 548 }
 549
 550 void instruction_breakpoint_exception(struct pt_regs *regs)
 551 {
 552         if (notify_die(DIE_IABR_MATCH, "iabr_match", regs, 5,
 553                                         5, SIGTRAP) == NOTIFY_STOP)
 554                 return;
 555         if (debugger_iabr_match(regs))
 556                 return;
 557         _exception(SIGTRAP, regs, TRAP_BRKPT, regs->nip);
 558 }
 559
 560 void RunModeException(struct pt_regs *regs)
 561 {
 562         _exception(SIGTRAP, regs, 0, 0);
 563 }
 564
 565 void __kprobes single_step_exception(struct pt_regs *regs)
 566 {
 567         regs->msr &= ~(MSR_SE | MSR_BE);  /* Turn off 'trace' bits */
 568
 569         if (notify_die(DIE_SSTEP, "single_step", regs, 5,
 570                                         5, SIGTRAP) == NOTIFY_STOP)
 571                 return;
 572         if (debugger_sstep(regs))
 573                 return;
 574
 575         _exception(SIGTRAP, regs, TRAP_TRACE, regs->nip);
 576 }
 577
 578 /*
 579  * After we have successfully emulated an instruction, we have to
 580  * check if the instruction was being single-stepped, and if so,
 581  * pretend we got a single-step exception.  This was pointed out
 582  * by Kumar Gala.  -- paulus
 583  */
 584 static void emulate_single_step(struct pt_regs *regs)
 585 {
 586         if (single_stepping(regs)) {
 587                 clear_single_step(regs);
 588                 _exception(SIGTRAP, regs, TRAP_TRACE, 0);
 589         }
 590 }
 591
 592 static inline int __parse_fpscr(unsigned long fpscr)
 593 {
 594         int ret = 0;
 595
 596         /* Invalid operation */
 597         if ((fpscr & FPSCR_VE) && (fpscr & FPSCR_VX))
 598                 ret = FPE_FLTINV;
 599
 600         /* Overflow */
 601         else if ((fpscr & FPSCR_OE) && (fpscr & FPSCR_OX))
 602                 ret = FPE_FLTOVF;
 603
 604         /* Underflow */
 605         else if ((fpscr & FPSCR_UE) && (fpscr & FPSCR_UX))
 606                 ret = FPE_FLTUND;
 607
 608         /* Divide by zero */
 609         else if ((fpscr & FPSCR_ZE) && (fpscr & FPSCR_ZX))
 610                 ret = FPE_FLTDIV;
 611
 612         /* Inexact result */
 613         else if ((fpscr & FPSCR_XE) && (fpscr & FPSCR_XX))
 614                 ret = FPE_FLTRES;
 615
 616         return ret;
 617 }
 618
 619 static void parse_fpe(struct pt_regs *regs)
 620 {
 621         int code = 0;
 622
 623         flush_fp_to_thread(current);
 624
 625         code = __parse_fpscr(current->thread.fpscr.val);
 626
 627         _exception(SIGFPE, regs, code, regs->nip);
 628 }
 629
 630 /*
 631  * Illegal instruction emulation support.  Originally written to
 632  * provide the PVR to user applications using the mfspr rd, PVR.
 633  * Return non-zero if we can't emulate, or -EFAULT if the associated
 634  * memory access caused an access fault.  Return zero on success.
 635  *
 636  * There are a couple of ways to do this, either "decode" the instruction
 637  * or directly match lots of bits.  In this case, matching lots of
 638  * bits is faster and easier.
 639  *
 640  */
 641 #define INST_MFSPR_PVR          0x7c1f42a6
 642 #define INST_MFSPR_PVR_MASK     0xfc1fffff
 643
 644 #define INST_DCBA               0x7c0005ec
 645 #define INST_DCBA_MASK          0xfc0007fe
 646
 647 #define INST_MCRXR              0x7c000400
 648 #define INST_MCRXR_MASK         0xfc0007fe
 649
 650 #define INST_STRING             0x7c00042a
 651 #define INST_STRING_MASK        0xfc0007fe
 652 #define INST_STRING_GEN_MASK    0xfc00067e
 653 #define INST_LSWI               0x7c0004aa
 654 #define INST_LSWX               0x7c00042a
 655 #define INST_STSWI              0x7c0005aa
 656 #define INST_STSWX              0x7c00052a
 657
 658 #define INST_POPCNTB            0x7c0000f4
 659 #define INST_POPCNTB_MASK       0xfc0007fe
 660
 661 #define INST_ISEL               0x7c00001e
 662 #define INST_ISEL_MASK          0xfc00003e
 663
 664 static int emulate_string_inst(struct pt_regs *regs, u32 instword)
 665 {
 666         u8 rT = (instword >> 21) & 0x1f;
 667         u8 rA = (instword >> 16) & 0x1f;
 668         u8 NB_RB = (instword >> 11) & 0x1f;
 669         u32 num_bytes;
 670         unsigned long EA;
 671         int pos = 0;
 672
 673         /* Early out if we are an invalid form of lswx */
 674         if ((instword & INST_STRING_MASK) == INST_LSWX)
 675                 if ((rT == rA) || (rT == NB_RB))
 676                         return -EINVAL;
 677
 678         EA = (rA == 0) ? 0 : regs->gpr[rA];
 679
 680         switch (instword & INST_STRING_MASK) {
 681                 case INST_LSWX:
 682                 case INST_STSWX:
 683                         EA += NB_RB;
 684                         num_bytes = regs->xer & 0x7f;
 685                         break;
 686                 case INST_LSWI:
 687                 case INST_STSWI:
 688                         num_bytes = (NB_RB == 0) ? 32 : NB_RB;
 689                         break;
 690                 default:
 691                         return -EINVAL;
 692         }
 693
 694         while (num_bytes != 0)
 695         {
 696                 u8 val;
 697                 u32 shift = 8 * (3 - (pos & 0x3));
 698
 699                 switch ((instword & INST_STRING_MASK)) {
 700                         case INST_LSWX:
 701                         case INST_LSWI:
 702                                 if (get_user(val, (u8 __user *)EA))
 703                                         return -EFAULT;
 704                                 /* first time updating this reg,
 705                                  * zero it out */
 706                                 if (pos == 0)
 707                                         regs->gpr[rT] = 0;
 708                                 regs->gpr[rT] |= val << shift;
 709                                 break;
 710                         case INST_STSWI:
 711                         case INST_STSWX:
 712                                 val = regs->gpr[rT] >> shift;
 713                                 if (put_user(val, (u8 __user *)EA))
 714                                         return -EFAULT;
 715                                 break;
 716                 }
 717                 /* move EA to next address */
 718                 EA += 1;
 719                 num_bytes--;
 720
 721                 /* manage our position within the register */
 722                 if (++pos == 4) {
 723                         pos = 0;
 724                         if (++rT == 32)
 725                                 rT = 0;
 726                 }
 727         }
 728
 729         return 0;
 730 }
 731
 732 static int emulate_popcntb_inst(struct pt_regs *regs, u32 instword)
 733 {
 734         u32 ra,rs;
 735         unsigned long tmp;
 736
 737         ra = (instword >> 16) & 0x1f;
 738         rs = (instword >> 21) & 0x1f;
 739
 740         tmp = regs->gpr[rs];
 741         tmp = tmp - ((tmp >> 1) & 0x5555555555555555ULL);
 742         tmp = (tmp & 0x3333333333333333ULL) + ((tmp >> 2) & 0x3333333333333333ULL);
 743         tmp = (tmp + (tmp >> 4)) & 0x0f0f0f0f0f0f0f0fULL;
 744         regs->gpr[ra] = tmp;
 745
 746         return 0;
 747 }
 748
 749 static int emulate_isel(struct pt_regs *regs, u32 instword)
 750 {
 751         u8 rT = (instword >> 21) & 0x1f;
 752         u8 rA = (instword >> 16) & 0x1f;
 753         u8 rB = (instword >> 11) & 0x1f;
 754         u8 BC = (instword >> 6) & 0x1f;
 755         u8 bit;
 756         unsigned long tmp;
 757
 758         tmp = (rA == 0) ? 0 : regs->gpr[rA];
 759         bit = (regs->ccr >> (31 - BC)) & 0x1;
 760
 761         regs->gpr[rT] = bit ? tmp : regs->gpr[rB];
 762
 763         return 0;
 764 }
 765
 766 static int emulate_instruction(struct pt_regs *regs)
 767 {
 768         u32 instword;
 769         u32 rd;
 770
 771         if (!user_mode(regs) || (regs->msr & MSR_LE))
 772                 return -EINVAL;
 773         CHECK_FULL_REGS(regs);
 774
 775         if (get_user(instword, (u32 __user *)(regs->nip)))
 776                 return -EFAULT;
 777
 778         /* Emulate the mfspr rD, PVR. */
 779         if ((instword & INST_MFSPR_PVR_MASK) == INST_MFSPR_PVR) {
 780                 rd = (instword >> 21) & 0x1f;
 781                 regs->gpr[rd] = mfspr(SPRN_PVR);
 782                 return 0;
 783         }
 784
 785         /* Emulating the dcba insn is just a no-op.  */
 786         if ((instword & INST_DCBA_MASK) == INST_DCBA)
 787                 return 0;
 788
 789         /* Emulate the mcrxr insn.  */
 790         if ((instword & INST_MCRXR_MASK) == INST_MCRXR) {
 791                 int shift = (instword >> 21) & 0x1c;
 792                 unsigned long msk = 0xf0000000UL >> shift;
 793
 794                 regs->ccr = (regs->ccr & ~msk) | ((regs->xer >> shift) & msk);
 795                 regs->xer &= ~0xf0000000UL;
 796                 return 0;
 797         }
 798
 799         /* Emulate load/store string insn. */
 800         if ((instword & INST_STRING_GEN_MASK) == INST_STRING)
 801                 return emulate_string_inst(regs, instword);
 802
 803         /* Emulate the popcntb (Population Count Bytes) instruction. */
 804         if ((instword & INST_POPCNTB_MASK) == INST_POPCNTB) {
 805                 return emulate_popcntb_inst(regs, instword);
 806         }
 807
 808         /* Emulate isel (Integer Select) instruction */
 809         if ((instword & INST_ISEL_MASK) == INST_ISEL) {
 810                 return emulate_isel(regs, instword);
 811         }
 812
 813         return -EINVAL;
 814 }
 815
 816 int is_valid_bugaddr(unsigned long addr)
 817 {
 818         return is_kernel_addr(addr);
 819 }
 820
 821 void __kprobes program_check_exception(struct pt_regs *regs)
 822 {
 823         unsigned int reason = get_reason(regs);
 824         extern int do_mathemu(struct pt_regs *regs);
 825
 826         /* We can now get here via a FP Unavailable exception if the core
 827          * has no FPU, in that case the reason flags will be 0 */
 828
 829         if (reason & REASON_FP) {
 830                 /* IEEE FP exception */
 831                 parse_fpe(regs);
 832                 return;
 833         }
 834         if (reason & REASON_TRAP) {
 835                 /* trap exception */
 836                 if (notify_die(DIE_BPT, "breakpoint", regs, 5, 5, SIGTRAP)
 837                                 == NOTIFY_STOP)
 838                         return;
 839                 if (debugger_bpt(regs))
 840                         return;
 841
 842                 if (!(regs->msr & MSR_PR) &&  /* not user-mode */
 843                     report_bug(regs->nip, regs) == BUG_TRAP_TYPE_WARN) {
 844                         regs->nip += 4;
 845                         return;
 846                 }
 847                 _exception(SIGTRAP, regs, TRAP_BRKPT, regs->nip);
 848                 return;
 849         }
 850
 851         local_irq_enable();
 852
 853 #ifdef CONFIG_MATH_EMULATION
 854         /* (reason & REASON_ILLEGAL) would be the obvious thing here,
 855          * but there seems to be a hardware bug on the 405GP (RevD)
 856          * that means ESR is sometimes set incorrectly - either to
 857          * ESR_DST (!?) or 0.  In the process of chasing this with the
 858          * hardware people - not sure if it can happen on any illegal
 859          * instruction or only on FP instructions, whether there is a
 860          * pattern to occurences etc. -dgibson 31/Mar/2003 */
 861         switch (do_mathemu(regs)) {
 862         case 0:
 863                 emulate_single_step(regs);
 864                 return;
 865         case 1: {
 866                         int code = 0;
 867                         code = __parse_fpscr(current->thread.fpscr.val);
 868                         _exception(SIGFPE, regs, code, regs->nip);
 869                         return;
 870                 }
 871         case -EFAULT:
 872                 _exception(SIGSEGV, regs, SEGV_MAPERR, regs->nip);
 873                 return;
 874         }
 875         /* fall through on any other errors */
 876 #endif /* CONFIG_MATH_EMULATION */
 877
 878         /* Try to emulate it if we should. */
 879         if (reason & (REASON_ILLEGAL | REASON_PRIVILEGED)) {
 880                 switch (emulate_instruction(regs)) {
 881                 case 0:
 882                         regs->nip += 4;
 883                         emulate_single_step(regs);
 884                         return;
 885                 case -EFAULT:
 886                         _exception(SIGSEGV, regs, SEGV_MAPERR, regs->nip);
 887                         return;
 888                 }
 889         }
 890
 891         if (reason & REASON_PRIVILEGED)
 892                 _exception(SIGILL, regs, ILL_PRVOPC, regs->nip);
 893         else
 894                 _exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
 895 }
 896
 897 void alignment_exception(struct pt_regs *regs)
 898 {
 899         int sig, code, fixed = 0;
 900
 901         /* we don't implement logging of alignment exceptions */
 902         if (!(current->thread.align_ctl & PR_UNALIGN_SIGBUS))
 903                 fixed = fix_alignment(regs);
 904
 905         if (fixed == 1) {
 906                 regs->nip += 4; /* skip over emulated instruction */
 907                 emulate_single_step(regs);
 908                 return;
 909         }
 910
 911         /* Operand address was bad */
 912         if (fixed == -EFAULT) {
 913                 sig = SIGSEGV;
 914                 code = SEGV_ACCERR;
 915         } else {
 916                 sig = SIGBUS;
 917                 code = BUS_ADRALN;
 918         }
 919         if (user_mode(regs))
 920                 _exception(sig, regs, code, regs->dar);
 921         else
 922                 bad_page_fault(regs, regs->dar, sig);
 923 }
 924
 925 void StackOverflow(struct pt_regs *regs)
 926 {
 927         printk(KERN_CRIT "Kernel stack overflow in process %p, r1=%lx\n",
 928                current, regs->gpr[1]);
 929         debugger(regs);
 930         show_regs(regs);
 931         panic("kernel stack overflow");
 932 }
 933
 934 void nonrecoverable_exception(struct pt_regs *regs)
 935 {
 936         printk(KERN_ERR "Non-recoverable exception at PC=%lx MSR=%lx\n",
 937                regs->nip, regs->msr);
 938         debugger(regs);
 939         die("nonrecoverable exception", regs, SIGKILL);
 940 }
 941
 942 void trace_syscall(struct pt_regs *regs)
 943 {
 944         printk("Task: %p(%d), PC: %08lX/%08lX, Syscall: %3ld, Result: %s%ld    %s\n",
 945                current, task_pid_nr(current), regs->nip, regs->link, regs->gpr[0],
 946                regs->ccr&0x10000000?"Error=":"", regs->gpr[3], print_tainted());
 947 }
 948
 949 void kernel_fp_unavailable_exception(struct pt_regs *regs)
 950 {
 951         printk(KERN_EMERG "Unrecoverable FP Unavailable Exception "
 952                           "%lx at %lx\n", regs->trap, regs->nip);
 953         die("Unrecoverable FP Unavailable Exception", regs, SIGABRT);
 954 }
 955
 956 void altivec_unavailable_exception(struct pt_regs *regs)
 957 {
 958         if (user_mode(regs)) {
 959                 /* A user program has executed an altivec instruction,
 960                    but this kernel doesn't support altivec. */
 961                 _exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
 962                 return;
 963         }
 964
 965         printk(KERN_EMERG "Unrecoverable VMX/Altivec Unavailable Exception "
 966                         "%lx at %lx\n", regs->trap, regs->nip);
 967         die("Unrecoverable VMX/Altivec Unavailable Exception", regs, SIGABRT);
 968 }
 969
 970 void vsx_unavailable_exception(struct pt_regs *regs)
 971 {
 972         if (user_mode(regs)) {
 973                 /* A user program has executed an vsx instruction,
 974                    but this kernel doesn't support vsx. */
 975                 _exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
 976                 return;
 977         }
 978
 979         printk(KERN_EMERG "Unrecoverable VSX Unavailable Exception "
 980                         "%lx at %lx\n", regs->trap, regs->nip);
 981         die("Unrecoverable VSX Unavailable Exception", regs, SIGABRT);
 982 }
 983
 984 void performance_monitor_exception(struct pt_regs *regs)
 985 {
 986         perf_irq(regs);
 987 }
 988
 989 #ifdef CONFIG_8xx
 990 void SoftwareEmulation(struct pt_regs *regs)
 991 {
 992         extern int do_mathemu(struct pt_regs *);
 993         extern int Soft_emulate_8xx(struct pt_regs *);
 994 #if defined(CONFIG_MATH_EMULATION) || defined(CONFIG_8XX_MINIMAL_FPEMU)
 995         int errcode;
 996 #endif
 997
 998         CHECK_FULL_REGS(regs);
 999
1000         if (!user_mode(regs)) {
1001                 debugger(regs);
1002                 die("Kernel Mode Software FPU Emulation", regs, SIGFPE);
1003         }
1004
1005 #ifdef CONFIG_MATH_EMULATION
1006         errcode = do_mathemu(regs);
1007
1008         switch (errcode) {
1009         case 0:
1010                 emulate_single_step(regs);
1011                 return;
1012         case 1: {
1013                         int code = 0;
1014                         code = __parse_fpscr(current->thread.fpscr.val);
1015                         _exception(SIGFPE, regs, code, regs->nip);
1016                         return;
1017                 }
1018         case -EFAULT:
1019                 _exception(SIGSEGV, regs, SEGV_MAPERR, regs->nip);
1020                 return;
1021         default:
1022                 _exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
1023                 return;
1024         }
1025
1026 #elif defined(CONFIG_8XX_MINIMAL_FPEMU)
1027         errcode = Soft_emulate_8xx(regs);
1028         switch (errcode) {
1029         case 0:
1030                 emulate_single_step(regs);
1031                 return;
1032         case 1:
1033                 _exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
1034                 return;
1035         case -EFAULT:
1036                 _exception(SIGSEGV, regs, SEGV_MAPERR, regs->nip);
1037                 return;
1038         }
1039 #else
1040         _exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
1041 #endif
1042 }
1043 #endif /* CONFIG_8xx */
1044
1045 #if defined(CONFIG_40x) || defined(CONFIG_BOOKE)
1046
1047 void __kprobes DebugException(struct pt_regs *regs, unsigned long debug_status)
1048 {
1049         if (debug_status & DBSR_IC) {   /* instruction completion */
1050                 regs->msr &= ~MSR_DE;
1051
1052                 /* Disable instruction completion */
1053                 mtspr(SPRN_DBCR0, mfspr(SPRN_DBCR0) & ~DBCR0_IC);
1054                 /* Clear the instruction completion event */
1055                 mtspr(SPRN_DBSR, DBSR_IC);
1056
1057                 if (notify_die(DIE_SSTEP, "single_step", regs, 5,
1058                                5, SIGTRAP) == NOTIFY_STOP) {
1059                         return;
1060                 }
1061
1062                 if (debugger_sstep(regs))
1063                         return;
1064
1065                 if (user_mode(regs)) {
1066                         current->thread.dbcr0 &= ~DBCR0_IC;
1067                 }
1068
1069                 _exception(SIGTRAP, regs, TRAP_TRACE, regs->nip);
1070         }
1071 }
1072 #endif /* CONFIG_4xx || CONFIG_BOOKE */
1073
1074 #if !defined(CONFIG_TAU_INT)
1075 void TAUException(struct pt_regs *regs)
1076 {
1077         printk("TAU trap at PC: %lx, MSR: %lx, vector=%lx    %s\n",
1078                regs->nip, regs->msr, regs->trap, print_tainted());
1079 }
1080 #endif /* CONFIG_INT_TAU */
1081
1082 #ifdef CONFIG_ALTIVEC
1083 void altivec_assist_exception(struct pt_regs *regs)
1084 {
1085         int err;
1086
1087         if (!user_mode(regs)) {
1088                 printk(KERN_EMERG "VMX/Altivec assist exception in kernel mode"
1089                        " at %lx\n", regs->nip);
1090                 die("Kernel VMX/Altivec assist exception", regs, SIGILL);
1091         }
1092
1093         flush_altivec_to_thread(current);
1094
1095         err = emulate_altivec(regs);
1096         if (err == 0) {
1097                 regs->nip += 4;         /* skip emulated instruction */
1098                 emulate_single_step(regs);
1099                 return;
1100         }
1101
1102         if (err == -EFAULT) {
1103                 /* got an error reading the instruction */
1104                 _exception(SIGSEGV, regs, SEGV_ACCERR, regs->nip);
1105         } else {
1106                 /* didn't recognize the instruction */
1107                 /* XXX quick hack for now: set the non-Java bit in the VSCR */
1108                 if (printk_ratelimit())
1109                         printk(KERN_ERR "Unrecognized altivec instruction "
1110                                "in %s at %lx\n", current->comm, regs->nip);
1111                 current->thread.vscr.u[3] |= 0x10000;
1112         }
1113 }
1114 #endif /* CONFIG_ALTIVEC */
1115
1116 #ifdef CONFIG_VSX
1117 void vsx_assist_exception(struct pt_regs *regs)
1118 {
1119         if (!user_mode(regs)) {
1120                 printk(KERN_EMERG "VSX assist exception in kernel mode"
1121                        " at %lx\n", regs->nip);
1122                 die("Kernel VSX assist exception", regs, SIGILL);
1123         }
1124
1125         flush_vsx_to_thread(current);
1126         printk(KERN_INFO "VSX assist not supported at %lx\n", regs->nip);
1127         _exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
1128 }
1129 #endif /* CONFIG_VSX */
1130
1131 #ifdef CONFIG_FSL_BOOKE
1132 void CacheLockingException(struct pt_regs *regs, unsigned long address,
1133                            unsigned long error_code)
1134 {
1135         /* We treat cache locking instructions from the user
1136          * as priv ops, in the future we could try to do
1137          * something smarter
1138          */
1139         if (error_code & (ESR_DLK|ESR_ILK))
1140                 _exception(SIGILL, regs, ILL_PRVOPC, regs->nip);
1141         return;
1142 }
1143 #endif /* CONFIG_FSL_BOOKE */
1144
1145 #ifdef CONFIG_SPE
1146 void SPEFloatingPointException(struct pt_regs *regs)
1147 {
1148         unsigned long spefscr;
1149         int fpexc_mode;
1150         int code = 0;
1151
1152         spefscr = current->thread.spefscr;
1153         fpexc_mode = current->thread.fpexc_mode;
1154
1155         /* Hardware does not neccessarily set sticky
1156          * underflow/overflow/invalid flags */
1157         if ((spefscr & SPEFSCR_FOVF) && (fpexc_mode & PR_FP_EXC_OVF)) {
1158                 code = FPE_FLTOVF;
1159                 spefscr |= SPEFSCR_FOVFS;
1160         }
1161         else if ((spefscr & SPEFSCR_FUNF) && (fpexc_mode & PR_FP_EXC_UND)) {
1162                 code = FPE_FLTUND;
1163                 spefscr |= SPEFSCR_FUNFS;
1164         }
1165         else if ((spefscr & SPEFSCR_FDBZ) && (fpexc_mode & PR_FP_EXC_DIV))
1166                 code = FPE_FLTDIV;
1167         else if ((spefscr & SPEFSCR_FINV) && (fpexc_mode & PR_FP_EXC_INV)) {
1168                 code = FPE_FLTINV;
1169                 spefscr |= SPEFSCR_FINVS;
1170         }
1171         else if ((spefscr & (SPEFSCR_FG | SPEFSCR_FX)) && (fpexc_mode & PR_FP_EXC_RES))
1172                 code = FPE_FLTRES;
1173
1174         current->thread.spefscr = spefscr;
1175
1176         _exception(SIGFPE, regs, code, regs->nip);
1177         return;
1178 }
1179 #endif
1180
1181 /*
1182  * We enter here if we get an unrecoverable exception, that is, one
1183  * that happened at a point where the RI (recoverable interrupt) bit
1184  * in the MSR is 0.  This indicates that SRR0/1 are live, and that
1185  * we therefore lost state by taking this exception.
1186  */
1187 void unrecoverable_exception(struct pt_regs *regs)
1188 {
1189         printk(KERN_EMERG "Unrecoverable exception %lx at %lx\n",
1190                regs->trap, regs->nip);
1191         die("Unrecoverable exception", regs, SIGABRT);
1192 }
1193
1194 #ifdef CONFIG_BOOKE_WDT
1195 /*
1196  * Default handler for a Watchdog exception,
1197  * spins until a reboot occurs
1198  */
1199 void __attribute__ ((weak)) WatchdogHandler(struct pt_regs *regs)
1200 {
1201         /* Generic WatchdogHandler, implement your own */
1202         mtspr(SPRN_TCR, mfspr(SPRN_TCR)&(~TCR_WIE));
1203         return;
1204 }
1205
1206 void WatchdogException(struct pt_regs *regs)
1207 {
1208         printk (KERN_EMERG "PowerPC Book-E Watchdog Exception\n");
1209         WatchdogHandler(regs);
1210 }
1211 #endif
1212
1213 /*
1214  * We enter here if we discover during exception entry that we are
1215  * running in supervisor mode with a userspace value in the stack pointer.
1216  */
1217 void kernel_bad_stack(struct pt_regs *regs)
1218 {
1219         printk(KERN_EMERG "Bad kernel stack pointer %lx at %lx\n",
1220                regs->gpr[1], regs->nip);
1221         die("Bad kernel stack pointer", regs, SIGABRT);
1222 }
1223
1224 void __init trap_init(void)
1225 {
1226 }