arch/ppc/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@cs.anu.edu.au)
  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/config.h>
  29 #include <linux/init.h>
  30 #include <linux/module.h>
  31 #include <linux/prctl.h>
  32
  33 #include <asm/pgtable.h>
  34 #include <asm/uaccess.h>
  35 #include <asm/system.h>
  36 #include <asm/io.h>
  37 #include <asm/reg.h>
  38 #include <asm/xmon.h>
  39 #include <asm/pmc.h>
  40
  41 #ifdef CONFIG_XMON
  42 extern int xmon_bpt(struct pt_regs *regs);
  43 extern int xmon_sstep(struct pt_regs *regs);
  44 extern int xmon_iabr_match(struct pt_regs *regs);
  45 extern int xmon_dabr_match(struct pt_regs *regs);
  46
  47 int (*debugger)(struct pt_regs *regs) = xmon;
  48 int (*debugger_bpt)(struct pt_regs *regs) = xmon_bpt;
  49 int (*debugger_sstep)(struct pt_regs *regs) = xmon_sstep;
  50 int (*debugger_iabr_match)(struct pt_regs *regs) = xmon_iabr_match;
  51 int (*debugger_dabr_match)(struct pt_regs *regs) = xmon_dabr_match;
  52 void (*debugger_fault_handler)(struct pt_regs *regs);
  53 #else
  54 #ifdef CONFIG_KGDB
  55 int (*debugger)(struct pt_regs *regs);
  56 int (*debugger_bpt)(struct pt_regs *regs);
  57 int (*debugger_sstep)(struct pt_regs *regs);
  58 int (*debugger_iabr_match)(struct pt_regs *regs);
  59 int (*debugger_dabr_match)(struct pt_regs *regs);
  60 void (*debugger_fault_handler)(struct pt_regs *regs);
  61 #else
  62 #define debugger(regs)                  do { } while (0)
  63 #define debugger_bpt(regs)              0
  64 #define debugger_sstep(regs)            0
  65 #define debugger_iabr_match(regs)       0
  66 #define debugger_dabr_match(regs)       0
  67 #define debugger_fault_handler          ((void (*)(struct pt_regs *))0)
  68 #endif
  69 #endif
  70
  71 /*
  72  * Trap & Exception support
  73  */
  74
  75 DEFINE_SPINLOCK(die_lock);
  76
  77 int die(const char * str, struct pt_regs * fp, long err)
  78 {
  79         static int die_counter;
  80         int nl = 0;
  81         console_verbose();
  82         spin_lock_irq(&die_lock);
  83         printk("Oops: %s, sig: %ld [#%d]\n", str, err, ++die_counter);
  84 #ifdef CONFIG_PREEMPT
  85         printk("PREEMPT ");
  86         nl = 1;
  87 #endif
  88 #ifdef CONFIG_SMP
  89         printk("SMP NR_CPUS=%d ", NR_CPUS);
  90         nl = 1;
  91 #endif
  92         if (nl)
  93                 printk("\n");
  94         show_regs(fp);
  95         spin_unlock_irq(&die_lock);
  96         /* do_exit() should take care of panic'ing from an interrupt
  97          * context so we don't handle it here
  98          */
  99         do_exit(err);
 100 }
 101
 102 void _exception(int signr, struct pt_regs *regs, int code, unsigned long addr)
 103 {
 104         siginfo_t info;
 105
 106         if (!user_mode(regs)) {
 107                 debugger(regs);
 108                 die("Exception in kernel mode", regs, signr);
 109         }
 110         info.si_signo = signr;
 111         info.si_errno = 0;
 112         info.si_code = code;
 113         info.si_addr = (void __user *) addr;
 114         force_sig_info(signr, &info, current);
 115
 116         /*
 117          * Init gets no signals that it doesn't have a handler for.
 118          * That's all very well, but if it has caused a synchronous
 119          * exception and we ignore the resulting signal, it will just
 120          * generate the same exception over and over again and we get
 121          * nowhere.  Better to kill it and let the kernel panic.
 122          */
 123         if (current->pid == 1) {
 124                 __sighandler_t handler;
 125
 126                 spin_lock_irq(&current->sighand->siglock);
 127                 handler = current->sighand->action[signr-1].sa.sa_handler;
 128                 spin_unlock_irq(&current->sighand->siglock);
 129                 if (handler == SIG_DFL) {
 130                         /* init has generated a synchronous exception
 131                            and it doesn't have a handler for the signal */
 132                         printk(KERN_CRIT "init has generated signal %d "
 133                                "but has no handler for it\n", signr);
 134                         do_exit(signr);
 135                 }
 136         }
 137 }
 138
 139 /*
 140  * I/O accesses can cause machine checks on powermacs.
 141  * Check if the NIP corresponds to the address of a sync
 142  * instruction for which there is an entry in the exception
 143  * table.
 144  * Note that the 601 only takes a machine check on TEA
 145  * (transfer error ack) signal assertion, and does not
 146  * set any of the top 16 bits of SRR1.
 147  *  -- paulus.
 148  */
 149 static inline int check_io_access(struct pt_regs *regs)
 150 {
 151 #if defined CONFIG_8xx
 152         unsigned long msr = regs->msr;
 153         const struct exception_table_entry *entry;
 154         unsigned int *nip = (unsigned int *)regs->nip;
 155
 156         if (((msr & 0xffff0000) == 0 || (msr & (0x80000 | 0x40000)))
 157             && (entry = search_exception_tables(regs->nip)) != NULL) {
 158                 /*
 159                  * Check that it's a sync instruction, or somewhere
 160                  * in the twi; isync; nop sequence that inb/inw/inl uses.
 161                  * As the address is in the exception table
 162                  * we should be able to read the instr there.
 163                  * For the debug message, we look at the preceding
 164                  * load or store.
 165                  */
 166                 if (*nip == 0x60000000)         /* nop */
 167                         nip -= 2;
 168                 else if (*nip == 0x4c00012c)    /* isync */
 169                         --nip;
 170                 /* eieio from I/O string functions */
 171                 else if ((*nip) == 0x7c0006ac || *(nip+1) == 0x7c0006ac)
 172                         nip += 2;
 173                 if (*nip == 0x7c0004ac || (*nip >> 26) == 3 ||
 174                         (*(nip+1) >> 26) == 3) {
 175                         /* sync or twi */
 176                         unsigned int rb;
 177
 178                         --nip;
 179                         rb = (*nip >> 11) & 0x1f;
 180                         printk(KERN_DEBUG "%s bad port %lx at %p\n",
 181                                (*nip & 0x100)? "OUT to": "IN from",
 182                                regs->gpr[rb] - _IO_BASE, nip);
 183                         regs->msr |= MSR_RI;
 184                         regs->nip = entry->fixup;
 185                         return 1;
 186                 }
 187         }
 188 #endif /* CONFIG_8xx */
 189         return 0;
 190 }
 191
 192 #if defined(CONFIG_4xx) || defined(CONFIG_BOOKE)
 193 /* On 4xx, the reason for the machine check or program exception
 194    is in the ESR. */
 195 #define get_reason(regs)        ((regs)->dsisr)
 196 #ifndef CONFIG_FSL_BOOKE
 197 #define get_mc_reason(regs)     ((regs)->dsisr)
 198 #else
 199 #define get_mc_reason(regs)     (mfspr(SPRN_MCSR))
 200 #endif
 201 #define REASON_FP               ESR_FP
 202 #define REASON_ILLEGAL          (ESR_PIL | ESR_PUO)
 203 #define REASON_PRIVILEGED       ESR_PPR
 204 #define REASON_TRAP             ESR_PTR
 205
 206 /* single-step stuff */
 207 #define single_stepping(regs)   (current->thread.dbcr0 & DBCR0_IC)
 208 #define clear_single_step(regs) (current->thread.dbcr0 &= ~DBCR0_IC)
 209
 210 #else
 211 /* On non-4xx, the reason for the machine check or program
 212    exception is in the MSR. */
 213 #define get_reason(regs)        ((regs)->msr)
 214 #define get_mc_reason(regs)     ((regs)->msr)
 215 #define REASON_FP               0x100000
 216 #define REASON_ILLEGAL          0x80000
 217 #define REASON_PRIVILEGED       0x40000
 218 #define REASON_TRAP             0x20000
 219
 220 #define single_stepping(regs)   ((regs)->msr & MSR_SE)
 221 #define clear_single_step(regs) ((regs)->msr &= ~MSR_SE)
 222 #endif
 223
 224 /*
 225  * This is "fall-back" implementation for configurations
 226  * which don't provide platform-specific machine check info
 227  */
 228 void __attribute__ ((weak))
 229 platform_machine_check(struct pt_regs *regs)
 230 {
 231 }
 232
 233 void machine_check_exception(struct pt_regs *regs)
 234 {
 235         unsigned long reason = get_mc_reason(regs);
 236
 237         if (user_mode(regs)) {
 238                 regs->msr |= MSR_RI;
 239                 _exception(SIGBUS, regs, BUS_ADRERR, regs->nip);
 240                 return;
 241         }
 242
 243 #if defined(CONFIG_8xx) && defined(CONFIG_PCI)
 244         /* the qspan pci read routines can cause machine checks -- Cort */
 245         bad_page_fault(regs, regs->dar, SIGBUS);
 246         return;
 247 #endif
 248
 249         if (debugger_fault_handler) {
 250                 debugger_fault_handler(regs);
 251                 regs->msr |= MSR_RI;
 252                 return;
 253         }
 254
 255         if (check_io_access(regs))
 256                 return;
 257
 258 #if defined(CONFIG_4xx) && !defined(CONFIG_440A)
 259         if (reason & ESR_IMCP) {
 260                 printk("Instruction");
 261                 mtspr(SPRN_ESR, reason & ~ESR_IMCP);
 262         } else
 263                 printk("Data");
 264         printk(" machine check in kernel mode.\n");
 265 #elif defined(CONFIG_440A)
 266         printk("Machine check in kernel mode.\n");
 267         if (reason & ESR_IMCP){
 268                 printk("Instruction Synchronous Machine Check exception\n");
 269                 mtspr(SPRN_ESR, reason & ~ESR_IMCP);
 270         }
 271         else {
 272                 u32 mcsr = mfspr(SPRN_MCSR);
 273                 if (mcsr & MCSR_IB)
 274                         printk("Instruction Read PLB Error\n");
 275                 if (mcsr & MCSR_DRB)
 276                         printk("Data Read PLB Error\n");
 277                 if (mcsr & MCSR_DWB)
 278                         printk("Data Write PLB Error\n");
 279                 if (mcsr & MCSR_TLBP)
 280                         printk("TLB Parity Error\n");
 281                 if (mcsr & MCSR_ICP){
 282                         flush_instruction_cache();
 283                         printk("I-Cache Parity Error\n");
 284                 }
 285                 if (mcsr & MCSR_DCSP)
 286                         printk("D-Cache Search Parity Error\n");
 287                 if (mcsr & MCSR_DCFP)
 288                         printk("D-Cache Flush Parity Error\n");
 289                 if (mcsr & MCSR_IMPE)
 290                         printk("Machine Check exception is imprecise\n");
 291
 292                 /* Clear MCSR */
 293                 mtspr(SPRN_MCSR, mcsr);
 294         }
 295 #elif defined (CONFIG_E500)
 296         printk("Machine check in kernel mode.\n");
 297         printk("Caused by (from MCSR=%lx): ", reason);
 298
 299         if (reason & MCSR_MCP)
 300                 printk("Machine Check Signal\n");
 301         if (reason & MCSR_ICPERR)
 302                 printk("Instruction Cache Parity Error\n");
 303         if (reason & MCSR_DCP_PERR)
 304                 printk("Data Cache Push Parity Error\n");
 305         if (reason & MCSR_DCPERR)
 306                 printk("Data Cache Parity Error\n");
 307         if (reason & MCSR_GL_CI)
 308                 printk("Guarded Load or Cache-Inhibited stwcx.\n");
 309         if (reason & MCSR_BUS_IAERR)
 310                 printk("Bus - Instruction Address Error\n");
 311         if (reason & MCSR_BUS_RAERR)
 312                 printk("Bus - Read Address Error\n");
 313         if (reason & MCSR_BUS_WAERR)
 314                 printk("Bus - Write Address Error\n");
 315         if (reason & MCSR_BUS_IBERR)
 316                 printk("Bus - Instruction Data Error\n");
 317         if (reason & MCSR_BUS_RBERR)
 318                 printk("Bus - Read Data Bus Error\n");
 319         if (reason & MCSR_BUS_WBERR)
 320                 printk("Bus - Read Data Bus Error\n");
 321         if (reason & MCSR_BUS_IPERR)
 322                 printk("Bus - Instruction Parity Error\n");
 323         if (reason & MCSR_BUS_RPERR)
 324                 printk("Bus - Read Parity Error\n");
 325 #elif defined (CONFIG_E200)
 326         printk("Machine check in kernel mode.\n");
 327         printk("Caused by (from MCSR=%lx): ", reason);
 328
 329         if (reason & MCSR_MCP)
 330                 printk("Machine Check Signal\n");
 331         if (reason & MCSR_CP_PERR)
 332                 printk("Cache Push Parity Error\n");
 333         if (reason & MCSR_CPERR)
 334                 printk("Cache Parity Error\n");
 335         if (reason & MCSR_EXCP_ERR)
 336                 printk("ISI, ITLB, or Bus Error on first instruction fetch for an exception handler\n");
 337         if (reason & MCSR_BUS_IRERR)
 338                 printk("Bus - Read Bus Error on instruction fetch\n");
 339         if (reason & MCSR_BUS_DRERR)
 340                 printk("Bus - Read Bus Error on data load\n");
 341         if (reason & MCSR_BUS_WRERR)
 342                 printk("Bus - Write Bus Error on buffered store or cache line push\n");
 343 #else /* !CONFIG_4xx && !CONFIG_E500 && !CONFIG_E200 */
 344         printk("Machine check in kernel mode.\n");
 345         printk("Caused by (from SRR1=%lx): ", reason);
 346         switch (reason & 0x601F0000) {
 347         case 0x80000:
 348                 printk("Machine check signal\n");
 349                 break;
 350         case 0:         /* for 601 */
 351         case 0x40000:
 352         case 0x140000:  /* 7450 MSS error and TEA */
 353                 printk("Transfer error ack signal\n");
 354                 break;
 355         case 0x20000:
 356                 printk("Data parity error signal\n");
 357                 break;
 358         case 0x10000:
 359                 printk("Address parity error signal\n");
 360                 break;
 361         case 0x20000000:
 362                 printk("L1 Data Cache error\n");
 363                 break;
 364         case 0x40000000:
 365                 printk("L1 Instruction Cache error\n");
 366                 break;
 367         case 0x00100000:
 368                 printk("L2 data cache parity error\n");
 369                 break;
 370         default:
 371                 printk("Unknown values in msr\n");
 372         }
 373 #endif /* CONFIG_4xx */
 374
 375         /*
 376          * Optional platform-provided routine to print out
 377          * additional info, e.g. bus error registers.
 378          */
 379         platform_machine_check(regs);
 380
 381         debugger(regs);
 382         die("machine check", regs, SIGBUS);
 383 }
 384
 385 void SMIException(struct pt_regs *regs)
 386 {
 387         debugger(regs);
 388 #if !(defined(CONFIG_XMON) || defined(CONFIG_KGDB))
 389         show_regs(regs);
 390         panic("System Management Interrupt");
 391 #endif
 392 }
 393
 394 void unknown_exception(struct pt_regs *regs)
 395 {
 396         printk("Bad trap at PC: %lx, MSR: %lx, vector=%lx    %s\n",
 397                regs->nip, regs->msr, regs->trap, print_tainted());
 398         _exception(SIGTRAP, regs, 0, 0);
 399 }
 400
 401 void instruction_breakpoint_exception(struct pt_regs *regs)
 402 {
 403         if (debugger_iabr_match(regs))
 404                 return;
 405         _exception(SIGTRAP, regs, TRAP_BRKPT, 0);
 406 }
 407
 408 void RunModeException(struct pt_regs *regs)
 409 {
 410         _exception(SIGTRAP, regs, 0, 0);
 411 }
 412
 413 /* Illegal instruction emulation support.  Originally written to
 414  * provide the PVR to user applications using the mfspr rd, PVR.
 415  * Return non-zero if we can't emulate, or -EFAULT if the associated
 416  * memory access caused an access fault.  Return zero on success.
 417  *
 418  * There are a couple of ways to do this, either "decode" the instruction
 419  * or directly match lots of bits.  In this case, matching lots of
 420  * bits is faster and easier.
 421  *
 422  */
 423 #define INST_MFSPR_PVR          0x7c1f42a6
 424 #define INST_MFSPR_PVR_MASK     0xfc1fffff
 425
 426 #define INST_DCBA               0x7c0005ec
 427 #define INST_DCBA_MASK          0x7c0007fe
 428
 429 #define INST_MCRXR              0x7c000400
 430 #define INST_MCRXR_MASK         0x7c0007fe
 431
 432 #define INST_STRING             0x7c00042a
 433 #define INST_STRING_MASK        0x7c0007fe
 434 #define INST_STRING_GEN_MASK    0x7c00067e
 435 #define INST_LSWI               0x7c0004aa
 436 #define INST_LSWX               0x7c00042a
 437 #define INST_STSWI              0x7c0005aa
 438 #define INST_STSWX              0x7c00052a
 439
 440 static int emulate_string_inst(struct pt_regs *regs, u32 instword)
 441 {
 442         u8 rT = (instword >> 21) & 0x1f;
 443         u8 rA = (instword >> 16) & 0x1f;
 444         u8 NB_RB = (instword >> 11) & 0x1f;
 445         u32 num_bytes;
 446         unsigned long EA;
 447         int pos = 0;
 448
 449         /* Early out if we are an invalid form of lswx */
 450         if ((instword & INST_STRING_MASK) == INST_LSWX)
 451                 if ((rT == rA) || (rT == NB_RB))
 452                         return -EINVAL;
 453
 454         EA = (rA == 0) ? 0 : regs->gpr[rA];
 455
 456         switch (instword & INST_STRING_MASK) {
 457                 case INST_LSWX:
 458                 case INST_STSWX:
 459                         EA += NB_RB;
 460                         num_bytes = regs->xer & 0x7f;
 461                         break;
 462                 case INST_LSWI:
 463                 case INST_STSWI:
 464                         num_bytes = (NB_RB == 0) ? 32 : NB_RB;
 465                         break;
 466                 default:
 467                         return -EINVAL;
 468         }
 469
 470         while (num_bytes != 0)
 471         {
 472                 u8 val;
 473                 u32 shift = 8 * (3 - (pos & 0x3));
 474
 475                 switch ((instword & INST_STRING_MASK)) {
 476                         case INST_LSWX:
 477                         case INST_LSWI:
 478                                 if (get_user(val, (u8 __user *)EA))
 479                                         return -EFAULT;
 480                                 /* first time updating this reg,
 481                                  * zero it out */
 482                                 if (pos == 0)
 483                                         regs->gpr[rT] = 0;
 484                                 regs->gpr[rT] |= val << shift;
 485                                 break;
 486                         case INST_STSWI:
 487                         case INST_STSWX:
 488                                 val = regs->gpr[rT] >> shift;
 489                                 if (put_user(val, (u8 __user *)EA))
 490                                         return -EFAULT;
 491                                 break;
 492                 }
 493                 /* move EA to next address */
 494                 EA += 1;
 495                 num_bytes--;
 496
 497                 /* manage our position within the register */
 498                 if (++pos == 4) {
 499                         pos = 0;
 500                         if (++rT == 32)
 501                                 rT = 0;
 502                 }
 503         }
 504
 505         return 0;
 506 }
 507
 508 static int emulate_instruction(struct pt_regs *regs)
 509 {
 510         u32 instword;
 511         u32 rd;
 512
 513         if (!user_mode(regs))
 514                 return -EINVAL;
 515         CHECK_FULL_REGS(regs);
 516
 517         if (get_user(instword, (u32 __user *)(regs->nip)))
 518                 return -EFAULT;
 519
 520         /* Emulate the mfspr rD, PVR.
 521          */
 522         if ((instword & INST_MFSPR_PVR_MASK) == INST_MFSPR_PVR) {
 523                 rd = (instword >> 21) & 0x1f;
 524                 regs->gpr[rd] = mfspr(SPRN_PVR);
 525                 return 0;
 526         }
 527
 528         /* Emulating the dcba insn is just a no-op.  */
 529         if ((instword & INST_DCBA_MASK) == INST_DCBA)
 530                 return 0;
 531
 532         /* Emulate the mcrxr insn.  */
 533         if ((instword & INST_MCRXR_MASK) == INST_MCRXR) {
 534                 int shift = (instword >> 21) & 0x1c;
 535                 unsigned long msk = 0xf0000000UL >> shift;
 536
 537                 regs->ccr = (regs->ccr & ~msk) | ((regs->xer >> shift) & msk);
 538                 regs->xer &= ~0xf0000000UL;
 539                 return 0;
 540         }
 541
 542         /* Emulate load/store string insn. */
 543         if ((instword & INST_STRING_GEN_MASK) == INST_STRING)
 544                 return emulate_string_inst(regs, instword);
 545
 546         return -EINVAL;
 547 }
 548
 549 /*
 550  * After we have successfully emulated an instruction, we have to
 551  * check if the instruction was being single-stepped, and if so,
 552  * pretend we got a single-step exception.  This was pointed out
 553  * by Kumar Gala.  -- paulus
 554  */
 555 static void emulate_single_step(struct pt_regs *regs)
 556 {
 557         if (single_stepping(regs)) {
 558                 clear_single_step(regs);
 559                 _exception(SIGTRAP, regs, TRAP_TRACE, 0);
 560         }
 561 }
 562
 563 /*
 564  * Look through the list of trap instructions that are used for BUG(),
 565  * BUG_ON() and WARN_ON() and see if we hit one.  At this point we know
 566  * that the exception was caused by a trap instruction of some kind.
 567  * Returns 1 if we should continue (i.e. it was a WARN_ON) or 0
 568  * otherwise.
 569  */
 570 extern struct bug_entry __start___bug_table[], __stop___bug_table[];
 571
 572 #ifndef CONFIG_MODULES
 573 #define module_find_bug(x)      NULL
 574 #endif
 575
 576 struct bug_entry *find_bug(unsigned long bugaddr)
 577 {
 578         struct bug_entry *bug;
 579
 580         for (bug = __start___bug_table; bug < __stop___bug_table; ++bug)
 581                 if (bugaddr == bug->bug_addr)
 582                         return bug;
 583         return module_find_bug(bugaddr);
 584 }
 585
 586 int check_bug_trap(struct pt_regs *regs)
 587 {
 588         struct bug_entry *bug;
 589         unsigned long addr;
 590
 591         if (regs->msr & MSR_PR)
 592                 return 0;       /* not in kernel */
 593         addr = regs->nip;       /* address of trap instruction */
 594         if (addr < PAGE_OFFSET)
 595                 return 0;
 596         bug = find_bug(regs->nip);
 597         if (bug == NULL)
 598                 return 0;
 599         if (bug->line & BUG_WARNING_TRAP) {
 600                 /* this is a WARN_ON rather than BUG/BUG_ON */
 601 #ifdef CONFIG_XMON
 602                 xmon_printf(KERN_ERR "Badness in %s at %s:%ld\n",
 603                        bug->function, bug->file,
 604                        bug->line & ~BUG_WARNING_TRAP);
 605 #endif /* CONFIG_XMON */
 606                 printk(KERN_ERR "Badness in %s at %s:%ld\n",
 607                        bug->function, bug->file,
 608                        bug->line & ~BUG_WARNING_TRAP);
 609                 dump_stack();
 610                 return 1;
 611         }
 612 #ifdef CONFIG_XMON
 613         xmon_printf(KERN_CRIT "kernel BUG in %s at %s:%ld!\n",
 614                bug->function, bug->file, bug->line);
 615         xmon(regs);
 616 #endif /* CONFIG_XMON */
 617         printk(KERN_CRIT "kernel BUG in %s at %s:%ld!\n",
 618                bug->function, bug->file, bug->line);
 619
 620         return 0;
 621 }
 622
 623 void program_check_exception(struct pt_regs *regs)
 624 {
 625         unsigned int reason = get_reason(regs);
 626         extern int do_mathemu(struct pt_regs *regs);
 627
 628 #ifdef CONFIG_MATH_EMULATION
 629         /* (reason & REASON_ILLEGAL) would be the obvious thing here,
 630          * but there seems to be a hardware bug on the 405GP (RevD)
 631          * that means ESR is sometimes set incorrectly - either to
 632          * ESR_DST (!?) or 0.  In the process of chasing this with the
 633          * hardware people - not sure if it can happen on any illegal
 634          * instruction or only on FP instructions, whether there is a
 635          * pattern to occurences etc. -dgibson 31/Mar/2003 */
 636         if (!(reason & REASON_TRAP) && do_mathemu(regs) == 0) {
 637                 emulate_single_step(regs);
 638                 return;
 639         }
 640 #endif /* CONFIG_MATH_EMULATION */
 641
 642         if (reason & REASON_FP) {
 643                 /* IEEE FP exception */
 644                 int code = 0;
 645                 u32 fpscr;
 646
 647                 /* We must make sure the FP state is consistent with
 648                  * our MSR_FP in regs
 649                  */
 650                 preempt_disable();
 651                 if (regs->msr & MSR_FP)
 652                         giveup_fpu(current);
 653                 preempt_enable();
 654
 655                 fpscr = current->thread.fpscr.val;
 656                 fpscr &= fpscr << 22;   /* mask summary bits with enables */
 657                 if (fpscr & FPSCR_VX)
 658                         code = FPE_FLTINV;
 659                 else if (fpscr & FPSCR_OX)
 660                         code = FPE_FLTOVF;
 661                 else if (fpscr & FPSCR_UX)
 662                         code = FPE_FLTUND;
 663                 else if (fpscr & FPSCR_ZX)
 664                         code = FPE_FLTDIV;
 665                 else if (fpscr & FPSCR_XX)
 666                         code = FPE_FLTRES;
 667                 _exception(SIGFPE, regs, code, regs->nip);
 668                 return;
 669         }
 670
 671         if (reason & REASON_TRAP) {
 672                 /* trap exception */
 673                 if (debugger_bpt(regs))
 674                         return;
 675                 if (check_bug_trap(regs)) {
 676                         regs->nip += 4;
 677                         return;
 678                 }
 679                 _exception(SIGTRAP, regs, TRAP_BRKPT, 0);
 680                 return;
 681         }
 682
 683         /* Try to emulate it if we should. */
 684         if (reason & (REASON_ILLEGAL | REASON_PRIVILEGED)) {
 685                 switch (emulate_instruction(regs)) {
 686                 case 0:
 687                         regs->nip += 4;
 688                         emulate_single_step(regs);
 689                         return;
 690                 case -EFAULT:
 691                         _exception(SIGSEGV, regs, SEGV_MAPERR, regs->nip);
 692                         return;
 693                 }
 694         }
 695
 696         if (reason & REASON_PRIVILEGED)
 697                 _exception(SIGILL, regs, ILL_PRVOPC, regs->nip);
 698         else
 699                 _exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
 700 }
 701
 702 void single_step_exception(struct pt_regs *regs)
 703 {
 704         regs->msr &= ~(MSR_SE | MSR_BE);  /* Turn off 'trace' bits */
 705         if (debugger_sstep(regs))
 706                 return;
 707         _exception(SIGTRAP, regs, TRAP_TRACE, 0);
 708 }
 709
 710 void alignment_exception(struct pt_regs *regs)
 711 {
 712         int fixed;
 713
 714         fixed = fix_alignment(regs);
 715         if (fixed == 1) {
 716                 regs->nip += 4; /* skip over emulated instruction */
 717                 emulate_single_step(regs);
 718                 return;
 719         }
 720         if (fixed == -EFAULT) {
 721                 /* fixed == -EFAULT means the operand address was bad */
 722                 if (user_mode(regs))
 723                         _exception(SIGSEGV, regs, SEGV_ACCERR, regs->dar);
 724                 else
 725                         bad_page_fault(regs, regs->dar, SIGSEGV);
 726                 return;
 727         }
 728         _exception(SIGBUS, regs, BUS_ADRALN, regs->dar);
 729 }
 730
 731 void StackOverflow(struct pt_regs *regs)
 732 {
 733         printk(KERN_CRIT "Kernel stack overflow in process %p, r1=%lx\n",
 734                current, regs->gpr[1]);
 735         debugger(regs);
 736         show_regs(regs);
 737         panic("kernel stack overflow");
 738 }
 739
 740 void nonrecoverable_exception(struct pt_regs *regs)
 741 {
 742         printk(KERN_ERR "Non-recoverable exception at PC=%lx MSR=%lx\n",
 743                regs->nip, regs->msr);
 744         debugger(regs);
 745         die("nonrecoverable exception", regs, SIGKILL);
 746 }
 747
 748 void trace_syscall(struct pt_regs *regs)
 749 {
 750         printk("Task: %p(%d), PC: %08lX/%08lX, Syscall: %3ld, Result: %s%ld    %s\n",
 751                current, current->pid, regs->nip, regs->link, regs->gpr[0],
 752                regs->ccr&0x10000000?"Error=":"", regs->gpr[3], print_tainted());
 753 }
 754
 755 #ifdef CONFIG_8xx
 756 void SoftwareEmulation(struct pt_regs *regs)
 757 {
 758         extern int do_mathemu(struct pt_regs *);
 759         extern int Soft_emulate_8xx(struct pt_regs *);
 760         int errcode;
 761
 762         CHECK_FULL_REGS(regs);
 763
 764         if (!user_mode(regs)) {
 765                 debugger(regs);
 766                 die("Kernel Mode Software FPU Emulation", regs, SIGFPE);
 767         }
 768
 769 #ifdef CONFIG_MATH_EMULATION
 770         errcode = do_mathemu(regs);
 771 #else
 772         errcode = Soft_emulate_8xx(regs);
 773 #endif
 774         if (errcode) {
 775                 if (errcode > 0)
 776                         _exception(SIGFPE, regs, 0, 0);
 777                 else if (errcode == -EFAULT)
 778                         _exception(SIGSEGV, regs, 0, 0);
 779                 else
 780                         _exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
 781         } else
 782                 emulate_single_step(regs);
 783 }
 784 #endif /* CONFIG_8xx */
 785
 786 #if defined(CONFIG_40x) || defined(CONFIG_BOOKE)
 787
 788 void DebugException(struct pt_regs *regs, unsigned long debug_status)
 789 {
 790         if (debug_status & DBSR_IC) {   /* instruction completion */
 791                 regs->msr &= ~MSR_DE;
 792                 if (user_mode(regs)) {
 793                         current->thread.dbcr0 &= ~DBCR0_IC;
 794                 } else {
 795                         /* Disable instruction completion */
 796                         mtspr(SPRN_DBCR0, mfspr(SPRN_DBCR0) & ~DBCR0_IC);
 797                         /* Clear the instruction completion event */
 798                         mtspr(SPRN_DBSR, DBSR_IC);
 799                         if (debugger_sstep(regs))
 800                                 return;
 801                 }
 802                 _exception(SIGTRAP, regs, TRAP_TRACE, 0);
 803         }
 804 }
 805 #endif /* CONFIG_4xx || CONFIG_BOOKE */
 806
 807 #if !defined(CONFIG_TAU_INT)
 808 void TAUException(struct pt_regs *regs)
 809 {
 810         printk("TAU trap at PC: %lx, MSR: %lx, vector=%lx    %s\n",
 811                regs->nip, regs->msr, regs->trap, print_tainted());
 812 }
 813 #endif /* CONFIG_INT_TAU */
 814
 815 /*
 816  * FP unavailable trap from kernel - print a message, but let
 817  * the task use FP in the kernel until it returns to user mode.
 818  */
 819 void kernel_fp_unavailable_exception(struct pt_regs *regs)
 820 {
 821         regs->msr |= MSR_FP;
 822         printk(KERN_ERR "floating point used in kernel (task=%p, pc=%lx)\n",
 823                current, regs->nip);
 824 }
 825
 826 void altivec_unavailable_exception(struct pt_regs *regs)
 827 {
 828         static int kernel_altivec_count;
 829
 830 #ifndef CONFIG_ALTIVEC
 831         if (user_mode(regs)) {
 832                 /* A user program has executed an altivec instruction,
 833                    but this kernel doesn't support altivec. */
 834                 _exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
 835                 return;
 836         }
 837 #endif
 838         /* The kernel has executed an altivec instruction without
 839            first enabling altivec.  Whinge but let it do it. */
 840         if (++kernel_altivec_count < 10)
 841                 printk(KERN_ERR "AltiVec used in kernel (task=%p, pc=%lx)\n",
 842                        current, regs->nip);
 843         regs->msr |= MSR_VEC;
 844 }
 845
 846 #ifdef CONFIG_ALTIVEC
 847 void altivec_assist_exception(struct pt_regs *regs)
 848 {
 849         int err;
 850
 851         preempt_disable();
 852         if (regs->msr & MSR_VEC)
 853                 giveup_altivec(current);
 854         preempt_enable();
 855         if (!user_mode(regs)) {
 856                 printk(KERN_ERR "altivec assist exception in kernel mode"
 857                        " at %lx\n", regs->nip);
 858                 debugger(regs);
 859                 die("altivec assist exception", regs, SIGFPE);
 860                 return;
 861         }
 862
 863         err = emulate_altivec(regs);
 864         if (err == 0) {
 865                 regs->nip += 4;         /* skip emulated instruction */
 866                 emulate_single_step(regs);
 867                 return;
 868         }
 869
 870         if (err == -EFAULT) {
 871                 /* got an error reading the instruction */
 872                 _exception(SIGSEGV, regs, SEGV_ACCERR, regs->nip);
 873         } else {
 874                 /* didn't recognize the instruction */
 875                 /* XXX quick hack for now: set the non-Java bit in the VSCR */
 876                 printk(KERN_ERR "unrecognized altivec instruction "
 877                        "in %s at %lx\n", current->comm, regs->nip);
 878                 current->thread.vscr.u[3] |= 0x10000;
 879         }
 880 }
 881 #endif /* CONFIG_ALTIVEC */
 882
 883 #ifdef CONFIG_E500
 884 void performance_monitor_exception(struct pt_regs *regs)
 885 {
 886         perf_irq(regs);
 887 }
 888 #endif
 889
 890 #ifdef CONFIG_FSL_BOOKE
 891 void CacheLockingException(struct pt_regs *regs, unsigned long address,
 892                            unsigned long error_code)
 893 {
 894         /* We treat cache locking instructions from the user
 895          * as priv ops, in the future we could try to do
 896          * something smarter
 897          */
 898         if (error_code & (ESR_DLK|ESR_ILK))
 899                 _exception(SIGILL, regs, ILL_PRVOPC, regs->nip);
 900         return;
 901 }
 902 #endif /* CONFIG_FSL_BOOKE */
 903
 904 #ifdef CONFIG_SPE
 905 void SPEFloatingPointException(struct pt_regs *regs)
 906 {
 907         unsigned long spefscr;
 908         int fpexc_mode;
 909         int code = 0;
 910
 911         spefscr = current->thread.spefscr;
 912         fpexc_mode = current->thread.fpexc_mode;
 913
 914         /* Hardware does not neccessarily set sticky
 915          * underflow/overflow/invalid flags */
 916         if ((spefscr & SPEFSCR_FOVF) && (fpexc_mode & PR_FP_EXC_OVF)) {
 917                 code = FPE_FLTOVF;
 918                 spefscr |= SPEFSCR_FOVFS;
 919         }
 920         else if ((spefscr & SPEFSCR_FUNF) && (fpexc_mode & PR_FP_EXC_UND)) {
 921                 code = FPE_FLTUND;
 922                 spefscr |= SPEFSCR_FUNFS;
 923         }
 924         else if ((spefscr & SPEFSCR_FDBZ) && (fpexc_mode & PR_FP_EXC_DIV))
 925                 code = FPE_FLTDIV;
 926         else if ((spefscr & SPEFSCR_FINV) && (fpexc_mode & PR_FP_EXC_INV)) {
 927                 code = FPE_FLTINV;
 928                 spefscr |= SPEFSCR_FINVS;
 929         }
 930         else if ((spefscr & (SPEFSCR_FG | SPEFSCR_FX)) && (fpexc_mode & PR_FP_EXC_RES))
 931                 code = FPE_FLTRES;
 932
 933         current->thread.spefscr = spefscr;
 934
 935         _exception(SIGFPE, regs, code, regs->nip);
 936         return;
 937 }
 938 #endif
 939
 940 #ifdef CONFIG_BOOKE_WDT
 941 /*
 942  * Default handler for a Watchdog exception,
 943  * spins until a reboot occurs
 944  */
 945 void __attribute__ ((weak)) WatchdogHandler(struct pt_regs *regs)
 946 {
 947         /* Generic WatchdogHandler, implement your own */
 948         mtspr(SPRN_TCR, mfspr(SPRN_TCR)&(~TCR_WIE));
 949         return;
 950 }
 951
 952 void WatchdogException(struct pt_regs *regs)
 953 {
 954         printk (KERN_EMERG "PowerPC Book-E Watchdog Exception\n");
 955         WatchdogHandler(regs);
 956 }
 957 #endif
 958
 959 void __init trap_init(void)
 960 {
 961 }