arch/alpha/kernel/traps.c

   1 /*
   2  * arch/alpha/kernel/traps.c
   3  *
   4  * (C) Copyright 1994 Linus Torvalds
   5  */
   6
   7 /*
   8  * This file initializes the trap entry points
   9  */
  10
  11 #include <linux/jiffies.h>
  12 #include <linux/mm.h>
  13 #include <linux/sched.h>
  14 #include <linux/tty.h>
  15 #include <linux/delay.h>
  16 #include <linux/module.h>
  17 #include <linux/init.h>
  18 #include <linux/kallsyms.h>
  19 #include <linux/ratelimit.h>
  20
  21 #include <asm/gentrap.h>
  22 #include <asm/uaccess.h>
  23 #include <asm/unaligned.h>
  24 #include <asm/sysinfo.h>
  25 #include <asm/hwrpb.h>
  26 #include <asm/mmu_context.h>
  27 #include <asm/special_insns.h>
  28
  29 #include "proto.h"
  30
  31 /* Work-around for some SRMs which mishandle opDEC faults.  */
  32
  33 static int opDEC_fix;
  34
  35 static void __cpuinit
  36 opDEC_check(void)
  37 {
  38         __asm__ __volatile__ (
  39         /* Load the address of... */
  40         "       br      $16, 1f\n"
  41         /* A stub instruction fault handler.  Just add 4 to the
  42            pc and continue.  */
  43         "       ldq     $16, 8($sp)\n"
  44         "       addq    $16, 4, $16\n"
  45         "       stq     $16, 8($sp)\n"
  46         "       call_pal %[rti]\n"
  47         /* Install the instruction fault handler.  */
  48         "1:     lda     $17, 3\n"
  49         "       call_pal %[wrent]\n"
  50         /* With that in place, the fault from the round-to-minf fp
  51            insn will arrive either at the "lda 4" insn (bad) or one
  52            past that (good).  This places the correct fixup in %0.  */
  53         "       lda %[fix], 0\n"
  54         "       cvttq/svm $f31,$f31\n"
  55         "       lda %[fix], 4"
  56         : [fix] "=r" (opDEC_fix)
  57         : [rti] "n" (PAL_rti), [wrent] "n" (PAL_wrent)
  58         : "$0", "$1", "$16", "$17", "$22", "$23", "$24", "$25");
  59
  60         if (opDEC_fix)
  61                 printk("opDEC fixup enabled.\n");
  62 }
  63
  64 void
  65 dik_show_regs(struct pt_regs *regs, unsigned long *r9_15)
  66 {
  67         printk("pc = [<%016lx>]  ra = [<%016lx>]  ps = %04lx    %s\n",
  68                regs->pc, regs->r26, regs->ps, print_tainted());
  69         print_symbol("pc is at %s\n", regs->pc);
  70         print_symbol("ra is at %s\n", regs->r26 );
  71         printk("v0 = %016lx  t0 = %016lx  t1 = %016lx\n",
  72                regs->r0, regs->r1, regs->r2);
  73         printk("t2 = %016lx  t3 = %016lx  t4 = %016lx\n",
  74                regs->r3, regs->r4, regs->r5);
  75         printk("t5 = %016lx  t6 = %016lx  t7 = %016lx\n",
  76                regs->r6, regs->r7, regs->r8);
  77
  78         if (r9_15) {
  79                 printk("s0 = %016lx  s1 = %016lx  s2 = %016lx\n",
  80                        r9_15[9], r9_15[10], r9_15[11]);
  81                 printk("s3 = %016lx  s4 = %016lx  s5 = %016lx\n",
  82                        r9_15[12], r9_15[13], r9_15[14]);
  83                 printk("s6 = %016lx\n", r9_15[15]);
  84         }
  85
  86         printk("a0 = %016lx  a1 = %016lx  a2 = %016lx\n",
  87                regs->r16, regs->r17, regs->r18);
  88         printk("a3 = %016lx  a4 = %016lx  a5 = %016lx\n",
  89                regs->r19, regs->r20, regs->r21);
  90         printk("t8 = %016lx  t9 = %016lx  t10= %016lx\n",
  91                regs->r22, regs->r23, regs->r24);
  92         printk("t11= %016lx  pv = %016lx  at = %016lx\n",
  93                regs->r25, regs->r27, regs->r28);
  94         printk("gp = %016lx  sp = %p\n", regs->gp, regs+1);
  95 #if 0
  96 __halt();
  97 #endif
  98 }
  99
 100 #if 0
 101 static char * ireg_name[] = {"v0", "t0", "t1", "t2", "t3", "t4", "t5", "t6",
 102                            "t7", "s0", "s1", "s2", "s3", "s4", "s5", "s6",
 103                            "a0", "a1", "a2", "a3", "a4", "a5", "t8", "t9",
 104                            "t10", "t11", "ra", "pv", "at", "gp", "sp", "zero"};
 105 #endif
 106
 107 static void
 108 dik_show_code(unsigned int *pc)
 109 {
 110         long i;
 111
 112         printk("Code:");
 113         for (i = -6; i < 2; i++) {
 114                 unsigned int insn;
 115                 if (__get_user(insn, (unsigned int __user *)pc + i))
 116                         break;
 117                 printk("%c%08x%c", i ? ' ' : '<', insn, i ? ' ' : '>');
 118         }
 119         printk("\n");
 120 }
 121
 122 static void
 123 dik_show_trace(unsigned long *sp)
 124 {
 125         long i = 0;
 126         printk("Trace:\n");
 127         while (0x1ff8 & (unsigned long) sp) {
 128                 extern char _stext[], _etext[];
 129                 unsigned long tmp = *sp;
 130                 sp++;
 131                 if (tmp < (unsigned long) &_stext)
 132                         continue;
 133                 if (tmp >= (unsigned long) &_etext)
 134                         continue;
 135                 printk("[<%lx>]", tmp);
 136                 print_symbol(" %s", tmp);
 137                 printk("\n");
 138                 if (i > 40) {
 139                         printk(" ...");
 140                         break;
 141                 }
 142         }
 143         printk("\n");
 144 }
 145
 146 static int kstack_depth_to_print = 24;
 147
 148 void show_stack(struct task_struct *task, unsigned long *sp)
 149 {
 150         unsigned long *stack;
 151         int i;
 152
 153         /*
 154          * debugging aid: "show_stack(NULL);" prints the
 155          * back trace for this cpu.
 156          */
 157         if(sp==NULL)
 158                 sp=(unsigned long*)&sp;
 159
 160         stack = sp;
 161         for(i=0; i < kstack_depth_to_print; i++) {
 162                 if (((long) stack & (THREAD_SIZE-1)) == 0)
 163                         break;
 164                 if (i && ((i % 4) == 0))
 165                         printk("\n       ");
 166                 printk("%016lx ", *stack++);
 167         }
 168         printk("\n");
 169         dik_show_trace(sp);
 170 }
 171
 172 void dump_stack(void)
 173 {
 174         show_stack(NULL, NULL);
 175 }
 176
 177 EXPORT_SYMBOL(dump_stack);
 178
 179 void
 180 die_if_kernel(char * str, struct pt_regs *regs, long err, unsigned long *r9_15)
 181 {
 182         if (regs->ps & 8)
 183                 return;
 184 #ifdef CONFIG_SMP
 185         printk("CPU %d ", hard_smp_processor_id());
 186 #endif
 187         printk("%s(%d): %s %ld\n", current->comm, task_pid_nr(current), str, err);
 188         dik_show_regs(regs, r9_15);
 189         add_taint(TAINT_DIE);
 190         dik_show_trace((unsigned long *)(regs+1));
 191         dik_show_code((unsigned int *)regs->pc);
 192
 193         if (test_and_set_thread_flag (TIF_DIE_IF_KERNEL)) {
 194                 printk("die_if_kernel recursion detected.\n");
 195                 local_irq_enable();
 196                 while (1);
 197         }
 198         do_exit(SIGSEGV);
 199 }
 200
 201 #ifndef CONFIG_MATHEMU
 202 static long dummy_emul(void) { return 0; }
 203 long (*alpha_fp_emul_imprecise)(struct pt_regs *regs, unsigned long writemask)
 204   = (void *)dummy_emul;
 205 long (*alpha_fp_emul) (unsigned long pc)
 206   = (void *)dummy_emul;
 207 #else
 208 long alpha_fp_emul_imprecise(struct pt_regs *regs, unsigned long writemask);
 209 long alpha_fp_emul (unsigned long pc);
 210 #endif
 211
 212 asmlinkage void
 213 do_entArith(unsigned long summary, unsigned long write_mask,
 214             struct pt_regs *regs)
 215 {
 216         long si_code = FPE_FLTINV;
 217         siginfo_t info;
 218
 219         if (summary & 1) {
 220                 /* Software-completion summary bit is set, so try to
 221                    emulate the instruction.  If the processor supports
 222                    precise exceptions, we don't have to search.  */
 223                 if (!amask(AMASK_PRECISE_TRAP))
 224                         si_code = alpha_fp_emul(regs->pc - 4);
 225                 else
 226                         si_code = alpha_fp_emul_imprecise(regs, write_mask);
 227                 if (si_code == 0)
 228                         return;
 229         }
 230         die_if_kernel("Arithmetic fault", regs, 0, NULL);
 231
 232         info.si_signo = SIGFPE;
 233         info.si_errno = 0;
 234         info.si_code = si_code;
 235         info.si_addr = (void __user *) regs->pc;
 236         send_sig_info(SIGFPE, &info, current);
 237 }
 238
 239 asmlinkage void
 240 do_entIF(unsigned long type, struct pt_regs *regs)
 241 {
 242         siginfo_t info;
 243         int signo, code;
 244
 245         if ((regs->ps & ~IPL_MAX) == 0) {
 246                 if (type == 1) {
 247                         const unsigned int *data
 248                           = (const unsigned int *) regs->pc;
 249                         printk("Kernel bug at %s:%d\n",
 250                                (const char *)(data[1] | (long)data[2] << 32),
 251                                data[0]);
 252                 }
 253                 die_if_kernel((type == 1 ? "Kernel Bug" : "Instruction fault"),
 254                               regs, type, NULL);
 255         }
 256
 257         switch (type) {
 258               case 0: /* breakpoint */
 259                 info.si_signo = SIGTRAP;
 260                 info.si_errno = 0;
 261                 info.si_code = TRAP_BRKPT;
 262                 info.si_trapno = 0;
 263                 info.si_addr = (void __user *) regs->pc;
 264
 265                 if (ptrace_cancel_bpt(current)) {
 266                         regs->pc -= 4;  /* make pc point to former bpt */
 267                 }
 268
 269                 send_sig_info(SIGTRAP, &info, current);
 270                 return;
 271
 272               case 1: /* bugcheck */
 273                 info.si_signo = SIGTRAP;
 274                 info.si_errno = 0;
 275                 info.si_code = __SI_FAULT;
 276                 info.si_addr = (void __user *) regs->pc;
 277                 info.si_trapno = 0;
 278                 send_sig_info(SIGTRAP, &info, current);
 279                 return;
 280
 281               case 2: /* gentrap */
 282                 info.si_addr = (void __user *) regs->pc;
 283                 info.si_trapno = regs->r16;
 284                 switch ((long) regs->r16) {
 285                 case GEN_INTOVF:
 286                         signo = SIGFPE;
 287                         code = FPE_INTOVF;
 288                         break;
 289                 case GEN_INTDIV:
 290                         signo = SIGFPE;
 291                         code = FPE_INTDIV;
 292                         break;
 293                 case GEN_FLTOVF:
 294                         signo = SIGFPE;
 295                         code = FPE_FLTOVF;
 296                         break;
 297                 case GEN_FLTDIV:
 298                         signo = SIGFPE;
 299                         code = FPE_FLTDIV;
 300                         break;
 301                 case GEN_FLTUND:
 302                         signo = SIGFPE;
 303                         code = FPE_FLTUND;
 304                         break;
 305                 case GEN_FLTINV:
 306                         signo = SIGFPE;
 307                         code = FPE_FLTINV;
 308                         break;
 309                 case GEN_FLTINE:
 310                         signo = SIGFPE;
 311                         code = FPE_FLTRES;
 312                         break;
 313                 case GEN_ROPRAND:
 314                         signo = SIGFPE;
 315                         code = __SI_FAULT;
 316                         break;
 317
 318                 case GEN_DECOVF:
 319                 case GEN_DECDIV:
 320                 case GEN_DECINV:
 321                 case GEN_ASSERTERR:
 322                 case GEN_NULPTRERR:
 323                 case GEN_STKOVF:
 324                 case GEN_STRLENERR:
 325                 case GEN_SUBSTRERR:
 326                 case GEN_RANGERR:
 327                 case GEN_SUBRNG:
 328                 case GEN_SUBRNG1:
 329                 case GEN_SUBRNG2:
 330                 case GEN_SUBRNG3:
 331                 case GEN_SUBRNG4:
 332                 case GEN_SUBRNG5:
 333                 case GEN_SUBRNG6:
 334                 case GEN_SUBRNG7:
 335                 default:
 336                         signo = SIGTRAP;
 337                         code = __SI_FAULT;
 338                         break;
 339                 }
 340
 341                 info.si_signo = signo;
 342                 info.si_errno = 0;
 343                 info.si_code = code;
 344                 info.si_addr = (void __user *) regs->pc;
 345                 send_sig_info(signo, &info, current);
 346                 return;
 347
 348               case 4: /* opDEC */
 349                 if (implver() == IMPLVER_EV4) {
 350                         long si_code;
 351
 352                         /* The some versions of SRM do not handle
 353                            the opDEC properly - they return the PC of the
 354                            opDEC fault, not the instruction after as the
 355                            Alpha architecture requires.  Here we fix it up.
 356                            We do this by intentionally causing an opDEC
 357                            fault during the boot sequence and testing if
 358                            we get the correct PC.  If not, we set a flag
 359                            to correct it every time through.  */
 360                         regs->pc += opDEC_fix;
 361
 362                         /* EV4 does not implement anything except normal
 363                            rounding.  Everything else will come here as
 364                            an illegal instruction.  Emulate them.  */
 365                         si_code = alpha_fp_emul(regs->pc - 4);
 366                         if (si_code == 0)
 367                                 return;
 368                         if (si_code > 0) {
 369                                 info.si_signo = SIGFPE;
 370                                 info.si_errno = 0;
 371                                 info.si_code = si_code;
 372                                 info.si_addr = (void __user *) regs->pc;
 373                                 send_sig_info(SIGFPE, &info, current);
 374                                 return;
 375                         }
 376                 }
 377                 break;
 378
 379               case 3: /* FEN fault */
 380                 /* Irritating users can call PAL_clrfen to disable the
 381                    FPU for the process.  The kernel will then trap in
 382                    do_switch_stack and undo_switch_stack when we try
 383                    to save and restore the FP registers.
 384
 385                    Given that GCC by default generates code that uses the
 386                    FP registers, PAL_clrfen is not useful except for DoS
 387                    attacks.  So turn the bleeding FPU back on and be done
 388                    with it.  */
 389                 current_thread_info()->pcb.flags |= 1;
 390                 __reload_thread(&current_thread_info()->pcb);
 391                 return;
 392
 393               case 5: /* illoc */
 394               default: /* unexpected instruction-fault type */
 395                       ;
 396         }
 397
 398         info.si_signo = SIGILL;
 399         info.si_errno = 0;
 400         info.si_code = ILL_ILLOPC;
 401         info.si_addr = (void __user *) regs->pc;
 402         send_sig_info(SIGILL, &info, current);
 403 }
 404
 405 /* There is an ifdef in the PALcode in MILO that enables a
 406    "kernel debugging entry point" as an unprivileged call_pal.
 407
 408    We don't want to have anything to do with it, but unfortunately
 409    several versions of MILO included in distributions have it enabled,
 410    and if we don't put something on the entry point we'll oops.  */
 411
 412 asmlinkage void
 413 do_entDbg(struct pt_regs *regs)
 414 {
 415         siginfo_t info;
 416
 417         die_if_kernel("Instruction fault", regs, 0, NULL);
 418
 419         info.si_signo = SIGILL;
 420         info.si_errno = 0;
 421         info.si_code = ILL_ILLOPC;
 422         info.si_addr = (void __user *) regs->pc;
 423         force_sig_info(SIGILL, &info, current);
 424 }
 425
 426
 427 /*
 428  * entUna has a different register layout to be reasonably simple. It
 429  * needs access to all the integer registers (the kernel doesn't use
 430  * fp-regs), and it needs to have them in order for simpler access.
 431  *
 432  * Due to the non-standard register layout (and because we don't want
 433  * to handle floating-point regs), user-mode unaligned accesses are
 434  * handled separately by do_entUnaUser below.
 435  *
 436  * Oh, btw, we don't handle the "gp" register correctly, but if we fault
 437  * on a gp-register unaligned load/store, something is _very_ wrong
 438  * in the kernel anyway..
 439  */
 440 struct allregs {
 441         unsigned long regs[32];
 442         unsigned long ps, pc, gp, a0, a1, a2;
 443 };
 444
 445 struct unaligned_stat {
 446         unsigned long count, va, pc;
 447 } unaligned[2];
 448
 449
 450 /* Macro for exception fixup code to access integer registers.  */
 451 #define una_reg(r)  (_regs[(r) >= 16 && (r) <= 18 ? (r)+19 : (r)])
 452
 453
 454 asmlinkage void
 455 do_entUna(void * va, unsigned long opcode, unsigned long reg,
 456           struct allregs *regs)
 457 {
 458         long error, tmp1, tmp2, tmp3, tmp4;
 459         unsigned long pc = regs->pc - 4;
 460         unsigned long *_regs = regs->regs;
 461         const struct exception_table_entry *fixup;
 462
 463         unaligned[0].count++;
 464         unaligned[0].va = (unsigned long) va;
 465         unaligned[0].pc = pc;
 466
 467         /* We don't want to use the generic get/put unaligned macros as
 468            we want to trap exceptions.  Only if we actually get an
 469            exception will we decide whether we should have caught it.  */
 470
 471         switch (opcode) {
 472         case 0x0c: /* ldwu */
 473                 __asm__ __volatile__(
 474                 "1:     ldq_u %1,0(%3)\n"
 475                 "2:     ldq_u %2,1(%3)\n"
 476                 "       extwl %1,%3,%1\n"
 477                 "       extwh %2,%3,%2\n"
 478                 "3:\n"
 479                 ".section __ex_table,\"a\"\n"
 480                 "       .long 1b - .\n"
 481                 "       lda %1,3b-1b(%0)\n"
 482                 "       .long 2b - .\n"
 483                 "       lda %2,3b-2b(%0)\n"
 484                 ".previous"
 485                         : "=r"(error), "=&r"(tmp1), "=&r"(tmp2)
 486                         : "r"(va), "0"(0));
 487                 if (error)
 488                         goto got_exception;
 489                 una_reg(reg) = tmp1|tmp2;
 490                 return;
 491
 492         case 0x28: /* ldl */
 493                 __asm__ __volatile__(
 494                 "1:     ldq_u %1,0(%3)\n"
 495                 "2:     ldq_u %2,3(%3)\n"
 496                 "       extll %1,%3,%1\n"
 497                 "       extlh %2,%3,%2\n"
 498                 "3:\n"
 499                 ".section __ex_table,\"a\"\n"
 500                 "       .long 1b - .\n"
 501                 "       lda %1,3b-1b(%0)\n"
 502                 "       .long 2b - .\n"
 503                 "       lda %2,3b-2b(%0)\n"
 504                 ".previous"
 505                         : "=r"(error), "=&r"(tmp1), "=&r"(tmp2)
 506                         : "r"(va), "0"(0));
 507                 if (error)
 508                         goto got_exception;
 509                 una_reg(reg) = (int)(tmp1|tmp2);
 510                 return;
 511
 512         case 0x29: /* ldq */
 513                 __asm__ __volatile__(
 514                 "1:     ldq_u %1,0(%3)\n"
 515                 "2:     ldq_u %2,7(%3)\n"
 516                 "       extql %1,%3,%1\n"
 517                 "       extqh %2,%3,%2\n"
 518                 "3:\n"
 519                 ".section __ex_table,\"a\"\n"
 520                 "       .long 1b - .\n"
 521                 "       lda %1,3b-1b(%0)\n"
 522                 "       .long 2b - .\n"
 523                 "       lda %2,3b-2b(%0)\n"
 524                 ".previous"
 525                         : "=r"(error), "=&r"(tmp1), "=&r"(tmp2)
 526                         : "r"(va), "0"(0));
 527                 if (error)
 528                         goto got_exception;
 529                 una_reg(reg) = tmp1|tmp2;
 530                 return;
 531
 532         /* Note that the store sequences do not indicate that they change
 533            memory because it _should_ be affecting nothing in this context.
 534            (Otherwise we have other, much larger, problems.)  */
 535         case 0x0d: /* stw */
 536                 __asm__ __volatile__(
 537                 "1:     ldq_u %2,1(%5)\n"
 538                 "2:     ldq_u %1,0(%5)\n"
 539                 "       inswh %6,%5,%4\n"
 540                 "       inswl %6,%5,%3\n"
 541                 "       mskwh %2,%5,%2\n"
 542                 "       mskwl %1,%5,%1\n"
 543                 "       or %2,%4,%2\n"
 544                 "       or %1,%3,%1\n"
 545                 "3:     stq_u %2,1(%5)\n"
 546                 "4:     stq_u %1,0(%5)\n"
 547                 "5:\n"
 548                 ".section __ex_table,\"a\"\n"
 549                 "       .long 1b - .\n"
 550                 "       lda %2,5b-1b(%0)\n"
 551                 "       .long 2b - .\n"
 552                 "       lda %1,5b-2b(%0)\n"
 553                 "       .long 3b - .\n"
 554                 "       lda $31,5b-3b(%0)\n"
 555                 "       .long 4b - .\n"
 556                 "       lda $31,5b-4b(%0)\n"
 557                 ".previous"
 558                         : "=r"(error), "=&r"(tmp1), "=&r"(tmp2),
 559                           "=&r"(tmp3), "=&r"(tmp4)
 560                         : "r"(va), "r"(una_reg(reg)), "0"(0));
 561                 if (error)
 562                         goto got_exception;
 563                 return;
 564
 565         case 0x2c: /* stl */
 566                 __asm__ __volatile__(
 567                 "1:     ldq_u %2,3(%5)\n"
 568                 "2:     ldq_u %1,0(%5)\n"
 569                 "       inslh %6,%5,%4\n"
 570                 "       insll %6,%5,%3\n"
 571                 "       msklh %2,%5,%2\n"
 572                 "       mskll %1,%5,%1\n"
 573                 "       or %2,%4,%2\n"
 574                 "       or %1,%3,%1\n"
 575                 "3:     stq_u %2,3(%5)\n"
 576                 "4:     stq_u %1,0(%5)\n"
 577                 "5:\n"
 578                 ".section __ex_table,\"a\"\n"
 579                 "       .long 1b - .\n"
 580                 "       lda %2,5b-1b(%0)\n"
 581                 "       .long 2b - .\n"
 582                 "       lda %1,5b-2b(%0)\n"
 583                 "       .long 3b - .\n"
 584                 "       lda $31,5b-3b(%0)\n"
 585                 "       .long 4b - .\n"
 586                 "       lda $31,5b-4b(%0)\n"
 587                 ".previous"
 588                         : "=r"(error), "=&r"(tmp1), "=&r"(tmp2),
 589                           "=&r"(tmp3), "=&r"(tmp4)
 590                         : "r"(va), "r"(una_reg(reg)), "0"(0));
 591                 if (error)
 592                         goto got_exception;
 593                 return;
 594
 595         case 0x2d: /* stq */
 596                 __asm__ __volatile__(
 597                 "1:     ldq_u %2,7(%5)\n"
 598                 "2:     ldq_u %1,0(%5)\n"
 599                 "       insqh %6,%5,%4\n"
 600                 "       insql %6,%5,%3\n"
 601                 "       mskqh %2,%5,%2\n"
 602                 "       mskql %1,%5,%1\n"
 603                 "       or %2,%4,%2\n"
 604                 "       or %1,%3,%1\n"
 605                 "3:     stq_u %2,7(%5)\n"
 606                 "4:     stq_u %1,0(%5)\n"
 607                 "5:\n"
 608                 ".section __ex_table,\"a\"\n\t"
 609                 "       .long 1b - .\n"
 610                 "       lda %2,5b-1b(%0)\n"
 611                 "       .long 2b - .\n"
 612                 "       lda %1,5b-2b(%0)\n"
 613                 "       .long 3b - .\n"
 614                 "       lda $31,5b-3b(%0)\n"
 615                 "       .long 4b - .\n"
 616                 "       lda $31,5b-4b(%0)\n"
 617                 ".previous"
 618                         : "=r"(error), "=&r"(tmp1), "=&r"(tmp2),
 619                           "=&r"(tmp3), "=&r"(tmp4)
 620                         : "r"(va), "r"(una_reg(reg)), "0"(0));
 621                 if (error)
 622                         goto got_exception;
 623                 return;
 624         }
 625
 626         printk("Bad unaligned kernel access at %016lx: %p %lx %lu\n",
 627                 pc, va, opcode, reg);
 628         do_exit(SIGSEGV);
 629
 630 got_exception:
 631         /* Ok, we caught the exception, but we don't want it.  Is there
 632            someone to pass it along to?  */
 633         if ((fixup = search_exception_tables(pc)) != 0) {
 634                 unsigned long newpc;
 635                 newpc = fixup_exception(una_reg, fixup, pc);
 636
 637                 printk("Forwarding unaligned exception at %lx (%lx)\n",
 638                        pc, newpc);
 639
 640                 regs->pc = newpc;
 641                 return;
 642         }
 643
 644         /*
 645          * Yikes!  No one to forward the exception to.
 646          * Since the registers are in a weird format, dump them ourselves.
 647          */
 648
 649         printk("%s(%d): unhandled unaligned exception\n",
 650                current->comm, task_pid_nr(current));
 651
 652         printk("pc = [<%016lx>]  ra = [<%016lx>]  ps = %04lx\n",
 653                pc, una_reg(26), regs->ps);
 654         printk("r0 = %016lx  r1 = %016lx  r2 = %016lx\n",
 655                una_reg(0), una_reg(1), una_reg(2));
 656         printk("r3 = %016lx  r4 = %016lx  r5 = %016lx\n",
 657                una_reg(3), una_reg(4), una_reg(5));
 658         printk("r6 = %016lx  r7 = %016lx  r8 = %016lx\n",
 659                una_reg(6), una_reg(7), una_reg(8));
 660         printk("r9 = %016lx  r10= %016lx  r11= %016lx\n",
 661                una_reg(9), una_reg(10), una_reg(11));
 662         printk("r12= %016lx  r13= %016lx  r14= %016lx\n",
 663                una_reg(12), una_reg(13), una_reg(14));
 664         printk("r15= %016lx\n", una_reg(15));
 665         printk("r16= %016lx  r17= %016lx  r18= %016lx\n",
 666                una_reg(16), una_reg(17), una_reg(18));
 667         printk("r19= %016lx  r20= %016lx  r21= %016lx\n",
 668                una_reg(19), una_reg(20), una_reg(21));
 669         printk("r22= %016lx  r23= %016lx  r24= %016lx\n",
 670                una_reg(22), una_reg(23), una_reg(24));
 671         printk("r25= %016lx  r27= %016lx  r28= %016lx\n",
 672                una_reg(25), una_reg(27), una_reg(28));
 673         printk("gp = %016lx  sp = %p\n", regs->gp, regs+1);
 674
 675         dik_show_code((unsigned int *)pc);
 676         dik_show_trace((unsigned long *)(regs+1));
 677
 678         if (test_and_set_thread_flag (TIF_DIE_IF_KERNEL)) {
 679                 printk("die_if_kernel recursion detected.\n");
 680                 local_irq_enable();
 681                 while (1);
 682         }
 683         do_exit(SIGSEGV);
 684 }
 685
 686 /*
 687  * Convert an s-floating point value in memory format to the
 688  * corresponding value in register format.  The exponent
 689  * needs to be remapped to preserve non-finite values
 690  * (infinities, not-a-numbers, denormals).
 691  */
 692 static inline unsigned long
 693 s_mem_to_reg (unsigned long s_mem)
 694 {
 695         unsigned long frac    = (s_mem >>  0) & 0x7fffff;
 696         unsigned long sign    = (s_mem >> 31) & 0x1;
 697         unsigned long exp_msb = (s_mem >> 30) & 0x1;
 698         unsigned long exp_low = (s_mem >> 23) & 0x7f;
 699         unsigned long exp;
 700
 701         exp = (exp_msb << 10) | exp_low;        /* common case */
 702         if (exp_msb) {
 703                 if (exp_low == 0x7f) {
 704                         exp = 0x7ff;
 705                 }
 706         } else {
 707                 if (exp_low == 0x00) {
 708                         exp = 0x000;
 709                 } else {
 710                         exp |= (0x7 << 7);
 711                 }
 712         }
 713         return (sign << 63) | (exp << 52) | (frac << 29);
 714 }
 715
 716 /*
 717  * Convert an s-floating point value in register format to the
 718  * corresponding value in memory format.
 719  */
 720 static inline unsigned long
 721 s_reg_to_mem (unsigned long s_reg)
 722 {
 723         return ((s_reg >> 62) << 30) | ((s_reg << 5) >> 34);
 724 }
 725
 726 /*
 727  * Handle user-level unaligned fault.  Handling user-level unaligned
 728  * faults is *extremely* slow and produces nasty messages.  A user
 729  * program *should* fix unaligned faults ASAP.
 730  *
 731  * Notice that we have (almost) the regular kernel stack layout here,
 732  * so finding the appropriate registers is a little more difficult
 733  * than in the kernel case.
 734  *
 735  * Finally, we handle regular integer load/stores only.  In
 736  * particular, load-linked/store-conditionally and floating point
 737  * load/stores are not supported.  The former make no sense with
 738  * unaligned faults (they are guaranteed to fail) and I don't think
 739  * the latter will occur in any decent program.
 740  *
 741  * Sigh. We *do* have to handle some FP operations, because GCC will
 742  * uses them as temporary storage for integer memory to memory copies.
 743  * However, we need to deal with stt/ldt and sts/lds only.
 744  */
 745
 746 #define OP_INT_MASK     ( 1L << 0x28 | 1L << 0x2c   /* ldl stl */       \
 747                         | 1L << 0x29 | 1L << 0x2d   /* ldq stq */       \
 748                         | 1L << 0x0c | 1L << 0x0d   /* ldwu stw */      \
 749                         | 1L << 0x0a | 1L << 0x0e ) /* ldbu stb */
 750
 751 #define OP_WRITE_MASK   ( 1L << 0x26 | 1L << 0x27   /* sts stt */       \
 752                         | 1L << 0x2c | 1L << 0x2d   /* stl stq */       \
 753                         | 1L << 0x0d | 1L << 0x0e ) /* stw stb */
 754
 755 #define R(x)    ((size_t) &((struct pt_regs *)0)->x)
 756
 757 static int unauser_reg_offsets[32] = {
 758         R(r0), R(r1), R(r2), R(r3), R(r4), R(r5), R(r6), R(r7), R(r8),
 759         /* r9 ... r15 are stored in front of regs.  */
 760         -56, -48, -40, -32, -24, -16, -8,
 761         R(r16), R(r17), R(r18),
 762         R(r19), R(r20), R(r21), R(r22), R(r23), R(r24), R(r25), R(r26),
 763         R(r27), R(r28), R(gp),
 764         0, 0
 765 };
 766
 767 #undef R
 768
 769 asmlinkage void
 770 do_entUnaUser(void __user * va, unsigned long opcode,
 771               unsigned long reg, struct pt_regs *regs)
 772 {
 773         static DEFINE_RATELIMIT_STATE(ratelimit, 5 * HZ, 5);
 774
 775         unsigned long tmp1, tmp2, tmp3, tmp4;
 776         unsigned long fake_reg, *reg_addr = &fake_reg;
 777         siginfo_t info;
 778         long error;
 779
 780         /* Check the UAC bits to decide what the user wants us to do
 781            with the unaliged access.  */
 782
 783         if (!test_thread_flag (TIF_UAC_NOPRINT)) {
 784                 if (__ratelimit(&ratelimit)) {
 785                         printk("%s(%d): unaligned trap at %016lx: %p %lx %ld\n",
 786                                current->comm, task_pid_nr(current),
 787                                regs->pc - 4, va, opcode, reg);
 788                 }
 789         }
 790         if (test_thread_flag (TIF_UAC_SIGBUS))
 791                 goto give_sigbus;
 792         /* Not sure why you'd want to use this, but... */
 793         if (test_thread_flag (TIF_UAC_NOFIX))
 794                 return;
 795
 796         /* Don't bother reading ds in the access check since we already
 797            know that this came from the user.  Also rely on the fact that
 798            the page at TASK_SIZE is unmapped and so can't be touched anyway. */
 799         if (!__access_ok((unsigned long)va, 0, USER_DS))
 800                 goto give_sigsegv;
 801
 802         ++unaligned[1].count;
 803         unaligned[1].va = (unsigned long)va;
 804         unaligned[1].pc = regs->pc - 4;
 805
 806         if ((1L << opcode) & OP_INT_MASK) {
 807                 /* it's an integer load/store */
 808                 if (reg < 30) {
 809                         reg_addr = (unsigned long *)
 810                           ((char *)regs + unauser_reg_offsets[reg]);
 811                 } else if (reg == 30) {
 812                         /* usp in PAL regs */
 813                         fake_reg = rdusp();
 814                 } else {
 815                         /* zero "register" */
 816                         fake_reg = 0;
 817                 }
 818         }
 819
 820         /* We don't want to use the generic get/put unaligned macros as
 821            we want to trap exceptions.  Only if we actually get an
 822            exception will we decide whether we should have caught it.  */
 823
 824         switch (opcode) {
 825         case 0x0c: /* ldwu */
 826                 __asm__ __volatile__(
 827                 "1:     ldq_u %1,0(%3)\n"
 828                 "2:     ldq_u %2,1(%3)\n"
 829                 "       extwl %1,%3,%1\n"
 830                 "       extwh %2,%3,%2\n"
 831                 "3:\n"
 832                 ".section __ex_table,\"a\"\n"
 833                 "       .long 1b - .\n"
 834                 "       lda %1,3b-1b(%0)\n"
 835                 "       .long 2b - .\n"
 836                 "       lda %2,3b-2b(%0)\n"
 837                 ".previous"
 838                         : "=r"(error), "=&r"(tmp1), "=&r"(tmp2)
 839                         : "r"(va), "0"(0));
 840                 if (error)
 841                         goto give_sigsegv;
 842                 *reg_addr = tmp1|tmp2;
 843                 break;
 844
 845         case 0x22: /* lds */
 846                 __asm__ __volatile__(
 847                 "1:     ldq_u %1,0(%3)\n"
 848                 "2:     ldq_u %2,3(%3)\n"
 849                 "       extll %1,%3,%1\n"
 850                 "       extlh %2,%3,%2\n"
 851                 "3:\n"
 852                 ".section __ex_table,\"a\"\n"
 853                 "       .long 1b - .\n"
 854                 "       lda %1,3b-1b(%0)\n"
 855                 "       .long 2b - .\n"
 856                 "       lda %2,3b-2b(%0)\n"
 857                 ".previous"
 858                         : "=r"(error), "=&r"(tmp1), "=&r"(tmp2)
 859                         : "r"(va), "0"(0));
 860                 if (error)
 861                         goto give_sigsegv;
 862                 alpha_write_fp_reg(reg, s_mem_to_reg((int)(tmp1|tmp2)));
 863                 return;
 864
 865         case 0x23: /* ldt */
 866                 __asm__ __volatile__(
 867                 "1:     ldq_u %1,0(%3)\n"
 868                 "2:     ldq_u %2,7(%3)\n"
 869                 "       extql %1,%3,%1\n"
 870                 "       extqh %2,%3,%2\n"
 871                 "3:\n"
 872                 ".section __ex_table,\"a\"\n"
 873                 "       .long 1b - .\n"
 874                 "       lda %1,3b-1b(%0)\n"
 875                 "       .long 2b - .\n"
 876                 "       lda %2,3b-2b(%0)\n"
 877                 ".previous"
 878                         : "=r"(error), "=&r"(tmp1), "=&r"(tmp2)
 879                         : "r"(va), "0"(0));
 880                 if (error)
 881                         goto give_sigsegv;
 882                 alpha_write_fp_reg(reg, tmp1|tmp2);
 883                 return;
 884
 885         case 0x28: /* ldl */
 886                 __asm__ __volatile__(
 887                 "1:     ldq_u %1,0(%3)\n"
 888                 "2:     ldq_u %2,3(%3)\n"
 889                 "       extll %1,%3,%1\n"
 890                 "       extlh %2,%3,%2\n"
 891                 "3:\n"
 892                 ".section __ex_table,\"a\"\n"
 893                 "       .long 1b - .\n"
 894                 "       lda %1,3b-1b(%0)\n"
 895                 "       .long 2b - .\n"
 896                 "       lda %2,3b-2b(%0)\n"
 897                 ".previous"
 898                         : "=r"(error), "=&r"(tmp1), "=&r"(tmp2)
 899                         : "r"(va), "0"(0));
 900                 if (error)
 901                         goto give_sigsegv;
 902                 *reg_addr = (int)(tmp1|tmp2);
 903                 break;
 904
 905         case 0x29: /* ldq */
 906                 __asm__ __volatile__(
 907                 "1:     ldq_u %1,0(%3)\n"
 908                 "2:     ldq_u %2,7(%3)\n"
 909                 "       extql %1,%3,%1\n"
 910                 "       extqh %2,%3,%2\n"
 911                 "3:\n"
 912                 ".section __ex_table,\"a\"\n"
 913                 "       .long 1b - .\n"
 914                 "       lda %1,3b-1b(%0)\n"
 915                 "       .long 2b - .\n"
 916                 "       lda %2,3b-2b(%0)\n"
 917                 ".previous"
 918                         : "=r"(error), "=&r"(tmp1), "=&r"(tmp2)
 919                         : "r"(va), "0"(0));
 920                 if (error)
 921                         goto give_sigsegv;
 922                 *reg_addr = tmp1|tmp2;
 923                 break;
 924
 925         /* Note that the store sequences do not indicate that they change
 926            memory because it _should_ be affecting nothing in this context.
 927            (Otherwise we have other, much larger, problems.)  */
 928         case 0x0d: /* stw */
 929                 __asm__ __volatile__(
 930                 "1:     ldq_u %2,1(%5)\n"
 931                 "2:     ldq_u %1,0(%5)\n"
 932                 "       inswh %6,%5,%4\n"
 933                 "       inswl %6,%5,%3\n"
 934                 "       mskwh %2,%5,%2\n"
 935                 "       mskwl %1,%5,%1\n"
 936                 "       or %2,%4,%2\n"
 937                 "       or %1,%3,%1\n"
 938                 "3:     stq_u %2,1(%5)\n"
 939                 "4:     stq_u %1,0(%5)\n"
 940                 "5:\n"
 941                 ".section __ex_table,\"a\"\n"
 942                 "       .long 1b - .\n"
 943                 "       lda %2,5b-1b(%0)\n"
 944                 "       .long 2b - .\n"
 945                 "       lda %1,5b-2b(%0)\n"
 946                 "       .long 3b - .\n"
 947                 "       lda $31,5b-3b(%0)\n"
 948                 "       .long 4b - .\n"
 949                 "       lda $31,5b-4b(%0)\n"
 950                 ".previous"
 951                         : "=r"(error), "=&r"(tmp1), "=&r"(tmp2),
 952                           "=&r"(tmp3), "=&r"(tmp4)
 953                         : "r"(va), "r"(*reg_addr), "0"(0));
 954                 if (error)
 955                         goto give_sigsegv;
 956                 return;
 957
 958         case 0x26: /* sts */
 959                 fake_reg = s_reg_to_mem(alpha_read_fp_reg(reg));
 960                 /* FALLTHRU */
 961
 962         case 0x2c: /* stl */
 963                 __asm__ __volatile__(
 964                 "1:     ldq_u %2,3(%5)\n"
 965                 "2:     ldq_u %1,0(%5)\n"
 966                 "       inslh %6,%5,%4\n"
 967                 "       insll %6,%5,%3\n"
 968                 "       msklh %2,%5,%2\n"
 969                 "       mskll %1,%5,%1\n"
 970                 "       or %2,%4,%2\n"
 971                 "       or %1,%3,%1\n"
 972                 "3:     stq_u %2,3(%5)\n"
 973                 "4:     stq_u %1,0(%5)\n"
 974                 "5:\n"
 975                 ".section __ex_table,\"a\"\n"
 976                 "       .long 1b - .\n"
 977                 "       lda %2,5b-1b(%0)\n"
 978                 "       .long 2b - .\n"
 979                 "       lda %1,5b-2b(%0)\n"
 980                 "       .long 3b - .\n"
 981                 "       lda $31,5b-3b(%0)\n"
 982                 "       .long 4b - .\n"
 983                 "       lda $31,5b-4b(%0)\n"
 984                 ".previous"
 985                         : "=r"(error), "=&r"(tmp1), "=&r"(tmp2),
 986                           "=&r"(tmp3), "=&r"(tmp4)
 987                         : "r"(va), "r"(*reg_addr), "0"(0));
 988                 if (error)
 989                         goto give_sigsegv;
 990                 return;
 991
 992         case 0x27: /* stt */
 993                 fake_reg = alpha_read_fp_reg(reg);
 994                 /* FALLTHRU */
 995
 996         case 0x2d: /* stq */
 997                 __asm__ __volatile__(
 998                 "1:     ldq_u %2,7(%5)\n"
 999                 "2:     ldq_u %1,0(%5)\n"
1000                 "       insqh %6,%5,%4\n"
1001                 "       insql %6,%5,%3\n"
1002                 "       mskqh %2,%5,%2\n"
1003                 "       mskql %1,%5,%1\n"
1004                 "       or %2,%4,%2\n"
1005                 "       or %1,%3,%1\n"
1006                 "3:     stq_u %2,7(%5)\n"
1007                 "4:     stq_u %1,0(%5)\n"
1008                 "5:\n"
1009                 ".section __ex_table,\"a\"\n\t"
1010                 "       .long 1b - .\n"
1011                 "       lda %2,5b-1b(%0)\n"
1012                 "       .long 2b - .\n"
1013                 "       lda %1,5b-2b(%0)\n"
1014                 "       .long 3b - .\n"
1015                 "       lda $31,5b-3b(%0)\n"
1016                 "       .long 4b - .\n"
1017                 "       lda $31,5b-4b(%0)\n"
1018                 ".previous"
1019                         : "=r"(error), "=&r"(tmp1), "=&r"(tmp2),
1020                           "=&r"(tmp3), "=&r"(tmp4)
1021                         : "r"(va), "r"(*reg_addr), "0"(0));
1022                 if (error)
1023                         goto give_sigsegv;
1024                 return;
1025
1026         default:
1027                 /* What instruction were you trying to use, exactly?  */
1028                 goto give_sigbus;
1029         }
1030
1031         /* Only integer loads should get here; everyone else returns early. */
1032         if (reg == 30)
1033                 wrusp(fake_reg);
1034         return;
1035
1036 give_sigsegv:
1037         regs->pc -= 4;  /* make pc point to faulting insn */
1038         info.si_signo = SIGSEGV;
1039         info.si_errno = 0;
1040
1041         /* We need to replicate some of the logic in mm/fault.c,
1042            since we don't have access to the fault code in the
1043            exception handling return path.  */
1044         if (!__access_ok((unsigned long)va, 0, USER_DS))
1045                 info.si_code = SEGV_ACCERR;
1046         else {
1047                 struct mm_struct *mm = current->mm;
1048                 down_read(&mm->mmap_sem);
1049                 if (find_vma(mm, (unsigned long)va))
1050                         info.si_code = SEGV_ACCERR;
1051                 else
1052                         info.si_code = SEGV_MAPERR;
1053                 up_read(&mm->mmap_sem);
1054         }
1055         info.si_addr = va;
1056         send_sig_info(SIGSEGV, &info, current);
1057         return;
1058
1059 give_sigbus:
1060         regs->pc -= 4;
1061         info.si_signo = SIGBUS;
1062         info.si_errno = 0;
1063         info.si_code = BUS_ADRALN;
1064         info.si_addr = va;
1065         send_sig_info(SIGBUS, &info, current);
1066         return;
1067 }
1068
1069 void __cpuinit
1070 trap_init(void)
1071 {
1072         /* Tell PAL-code what global pointer we want in the kernel.  */
1073         register unsigned long gptr __asm__("$29");
1074         wrkgp(gptr);
1075
1076         /* Hack for Multia (UDB) and JENSEN: some of their SRMs have
1077            a bug in the handling of the opDEC fault.  Fix it up if so.  */
1078         if (implver() == IMPLVER_EV4)
1079                 opDEC_check();
1080
1081         wrent(entArith, 1);
1082         wrent(entMM, 2);
1083         wrent(entIF, 3);
1084         wrent(entUna, 4);
1085         wrent(entSys, 5);
1086         wrent(entDbg, 6);
1087 }