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/mm.h>
  12 #include <linux/sched.h>
  13 #include <linux/tty.h>
  14 #include <linux/delay.h>
  15 #include <linux/smp_lock.h>
  16 #include <linux/module.h>
  17 #include <linux/init.h>
  18 #include <linux/kallsyms.h>
  19
  20 #include <asm/gentrap.h>
  21 #include <asm/uaccess.h>
  22 #include <asm/unaligned.h>
  23 #include <asm/sysinfo.h>
  24 #include <asm/hwrpb.h>
  25 #include <asm/mmu_context.h>
  26
  27 #include "proto.h"
  28
  29 /* Work-around for some SRMs which mishandle opDEC faults.  */
  30
  31 static int opDEC_fix;
  32
  33 static void __init
  34 opDEC_check(void)
  35 {
  36         __asm__ __volatile__ (
  37         /* Load the address of... */
  38         "       br      $16, 1f\n"
  39         /* A stub instruction fault handler.  Just add 4 to the
  40            pc and continue.  */
  41         "       ldq     $16, 8($sp)\n"
  42         "       addq    $16, 4, $16\n"
  43         "       stq     $16, 8($sp)\n"
  44         "       call_pal %[rti]\n"
  45         /* Install the instruction fault handler.  */
  46         "1:     lda     $17, 3\n"
  47         "       call_pal %[wrent]\n"
  48         /* With that in place, the fault from the round-to-minf fp
  49            insn will arrive either at the "lda 4" insn (bad) or one
  50            past that (good).  This places the correct fixup in %0.  */
  51         "       lda %[fix], 0\n"
  52         "       cvttq/svm $f31,$f31\n"
  53         "       lda %[fix], 4"
  54         : [fix] "=r" (opDEC_fix)
  55         : [rti] "n" (PAL_rti), [wrent] "n" (PAL_wrent)
  56         : "$0", "$1", "$16", "$17", "$22", "$23", "$24", "$25");
  57
  58         if (opDEC_fix)
  59                 printk("opDEC fixup enabled.\n");
  60 }
  61
  62 void
  63 dik_show_regs(struct pt_regs *regs, unsigned long *r9_15)
  64 {
  65         printk("pc = [<%016lx>]  ra = [<%016lx>]  ps = %04lx    %s\n",
  66                regs->pc, regs->r26, regs->ps, print_tainted());
  67         print_symbol("pc is at %s\n", regs->pc);
  68         print_symbol("ra is at %s\n", regs->r26 );
  69         printk("v0 = %016lx  t0 = %016lx  t1 = %016lx\n",
  70                regs->r0, regs->r1, regs->r2);
  71         printk("t2 = %016lx  t3 = %016lx  t4 = %016lx\n",
  72                regs->r3, regs->r4, regs->r5);
  73         printk("t5 = %016lx  t6 = %016lx  t7 = %016lx\n",
  74                regs->r6, regs->r7, regs->r8);
  75
  76         if (r9_15) {
  77                 printk("s0 = %016lx  s1 = %016lx  s2 = %016lx\n",
  78                        r9_15[9], r9_15[10], r9_15[11]);
  79                 printk("s3 = %016lx  s4 = %016lx  s5 = %016lx\n",
  80                        r9_15[12], r9_15[13], r9_15[14]);
  81                 printk("s6 = %016lx\n", r9_15[15]);
  82         }
  83
  84         printk("a0 = %016lx  a1 = %016lx  a2 = %016lx\n",
  85                regs->r16, regs->r17, regs->r18);
  86         printk("a3 = %016lx  a4 = %016lx  a5 = %016lx\n",
  87                regs->r19, regs->r20, regs->r21);
  88         printk("t8 = %016lx  t9 = %016lx  t10= %016lx\n",
  89                regs->r22, regs->r23, regs->r24);
  90         printk("t11= %016lx  pv = %016lx  at = %016lx\n",
  91                regs->r25, regs->r27, regs->r28);
  92         printk("gp = %016lx  sp = %p\n", regs->gp, regs+1);
  93 #if 0
  94 __halt();
  95 #endif
  96 }
  97
  98 #if 0
  99 static char * ireg_name[] = {"v0", "t0", "t1", "t2", "t3", "t4", "t5", "t6",
 100                            "t7", "s0", "s1", "s2", "s3", "s4", "s5", "s6",
 101                            "a0", "a1", "a2", "a3", "a4", "a5", "t8", "t9",
 102                            "t10", "t11", "ra", "pv", "at", "gp", "sp", "zero"};
 103 #endif
 104
 105 static void
 106 dik_show_code(unsigned int *pc)
 107 {
 108         long i;
 109
 110         printk("Code:");
 111         for (i = -6; i < 2; i++) {
 112                 unsigned int insn;
 113                 if (__get_user(insn, (unsigned int __user *)pc + i))
 114                         break;
 115                 printk("%c%08x%c", i ? ' ' : '<', insn, i ? ' ' : '>');
 116         }
 117         printk("\n");
 118 }
 119
 120 static void
 121 dik_show_trace(unsigned long *sp)
 122 {
 123         long i = 0;
 124         printk("Trace:\n");
 125         while (0x1ff8 & (unsigned long) sp) {
 126                 extern char _stext[], _etext[];
 127                 unsigned long tmp = *sp;
 128                 sp++;
 129                 if (tmp < (unsigned long) &_stext)
 130                         continue;
 131                 if (tmp >= (unsigned long) &_etext)
 132                         continue;
 133                 printk("[<%lx>]", tmp);
 134                 print_symbol(" %s", tmp);
 135                 printk("\n");
 136                 if (i > 40) {
 137                         printk(" ...");
 138                         break;
 139                 }
 140         }
 141         printk("\n");
 142 }
 143
 144 static int kstack_depth_to_print = 24;
 145
 146 void show_stack(struct task_struct *task, unsigned long *sp)
 147 {
 148         unsigned long *stack;
 149         int i;
 150
 151         /*
 152          * debugging aid: "show_stack(NULL);" prints the
 153          * back trace for this cpu.
 154          */
 155         if(sp==NULL)
 156                 sp=(unsigned long*)&sp;
 157
 158         stack = sp;
 159         for(i=0; i < kstack_depth_to_print; i++) {
 160                 if (((long) stack & (THREAD_SIZE-1)) == 0)
 161                         break;
 162                 if (i && ((i % 4) == 0))
 163                         printk("\n       ");
 164                 printk("%016lx ", *stack++);
 165         }
 166         printk("\n");
 167         dik_show_trace(sp);
 168 }
 169
 170 void dump_stack(void)
 171 {
 172         show_stack(NULL, NULL);
 173 }
 174
 175 EXPORT_SYMBOL(dump_stack);
 176
 177 void
 178 die_if_kernel(char * str, struct pt_regs *regs, long err, unsigned long *r9_15)
 179 {
 180         if (regs->ps & 8)
 181                 return;
 182 #ifdef CONFIG_SMP
 183         printk("CPU %d ", hard_smp_processor_id());
 184 #endif
 185         printk("%s(%d): %s %ld\n", current->comm, task_pid_nr(current), str, err);
 186         dik_show_regs(regs, r9_15);
 187         add_taint(TAINT_DIE);
 188         dik_show_trace((unsigned long *)(regs+1));
 189         dik_show_code((unsigned int *)regs->pc);
 190
 191         if (test_and_set_thread_flag (TIF_DIE_IF_KERNEL)) {
 192                 printk("die_if_kernel recursion detected.\n");
 193                 local_irq_enable();
 194                 while (1);
 195         }
 196         do_exit(SIGSEGV);
 197 }
 198
 199 #ifndef CONFIG_MATHEMU
 200 static long dummy_emul(void) { return 0; }
 201 long (*alpha_fp_emul_imprecise)(struct pt_regs *regs, unsigned long writemask)
 202   = (void *)dummy_emul;
 203 long (*alpha_fp_emul) (unsigned long pc)
 204   = (void *)dummy_emul;
 205 #else
 206 long alpha_fp_emul_imprecise(struct pt_regs *regs, unsigned long writemask);
 207 long alpha_fp_emul (unsigned long pc);
 208 #endif
 209
 210 asmlinkage void
 211 do_entArith(unsigned long summary, unsigned long write_mask,
 212             struct pt_regs *regs)
 213 {
 214         long si_code = FPE_FLTINV;
 215         siginfo_t info;
 216
 217         if (summary & 1) {
 218                 /* Software-completion summary bit is set, so try to
 219                    emulate the instruction.  If the processor supports
 220                    precise exceptions, we don't have to search.  */
 221                 if (!amask(AMASK_PRECISE_TRAP))
 222                         si_code = alpha_fp_emul(regs->pc - 4);
 223                 else
 224                         si_code = alpha_fp_emul_imprecise(regs, write_mask);
 225                 if (si_code == 0)
 226                         return;
 227         }
 228         die_if_kernel("Arithmetic fault", regs, 0, NULL);
 229
 230         info.si_signo = SIGFPE;
 231         info.si_errno = 0;
 232         info.si_code = si_code;
 233         info.si_addr = (void __user *) regs->pc;
 234         send_sig_info(SIGFPE, &info, current);
 235 }
 236
 237 asmlinkage void
 238 do_entIF(unsigned long type, struct pt_regs *regs)
 239 {
 240         siginfo_t info;
 241         int signo, code;
 242
 243         if ((regs->ps & ~IPL_MAX) == 0) {
 244                 if (type == 1) {
 245                         const unsigned int *data
 246                           = (const unsigned int *) regs->pc;
 247                         printk("Kernel bug at %s:%d\n",
 248                                (const char *)(data[1] | (long)data[2] << 32),
 249                                data[0]);
 250                 }
 251                 die_if_kernel((type == 1 ? "Kernel Bug" : "Instruction fault"),
 252                               regs, type, NULL);
 253         }
 254
 255         switch (type) {
 256               case 0: /* breakpoint */
 257                 info.si_signo = SIGTRAP;
 258                 info.si_errno = 0;
 259                 info.si_code = TRAP_BRKPT;
 260                 info.si_trapno = 0;
 261                 info.si_addr = (void __user *) regs->pc;
 262
 263                 if (ptrace_cancel_bpt(current)) {
 264                         regs->pc -= 4;  /* make pc point to former bpt */
 265                 }
 266
 267                 send_sig_info(SIGTRAP, &info, current);
 268                 return;
 269
 270               case 1: /* bugcheck */
 271                 info.si_signo = SIGTRAP;
 272                 info.si_errno = 0;
 273                 info.si_code = __SI_FAULT;
 274                 info.si_addr = (void __user *) regs->pc;
 275                 info.si_trapno = 0;
 276                 send_sig_info(SIGTRAP, &info, current);
 277                 return;
 278
 279               case 2: /* gentrap */
 280                 info.si_addr = (void __user *) regs->pc;
 281                 info.si_trapno = regs->r16;
 282                 switch ((long) regs->r16) {
 283                 case GEN_INTOVF:
 284                         signo = SIGFPE;
 285                         code = FPE_INTOVF;
 286                         break;
 287                 case GEN_INTDIV:
 288                         signo = SIGFPE;
 289                         code = FPE_INTDIV;
 290                         break;
 291                 case GEN_FLTOVF:
 292                         signo = SIGFPE;
 293                         code = FPE_FLTOVF;
 294                         break;
 295                 case GEN_FLTDIV:
 296                         signo = SIGFPE;
 297                         code = FPE_FLTDIV;
 298                         break;
 299                 case GEN_FLTUND:
 300                         signo = SIGFPE;
 301                         code = FPE_FLTUND;
 302                         break;
 303                 case GEN_FLTINV:
 304                         signo = SIGFPE;
 305                         code = FPE_FLTINV;
 306                         break;
 307                 case GEN_FLTINE:
 308                         signo = SIGFPE;
 309                         code = FPE_FLTRES;
 310                         break;
 311                 case GEN_ROPRAND:
 312                         signo = SIGFPE;
 313                         code = __SI_FAULT;
 314                         break;
 315
 316                 case GEN_DECOVF:
 317                 case GEN_DECDIV:
 318                 case GEN_DECINV:
 319                 case GEN_ASSERTERR:
 320                 case GEN_NULPTRERR:
 321                 case GEN_STKOVF:
 322                 case GEN_STRLENERR:
 323                 case GEN_SUBSTRERR:
 324                 case GEN_RANGERR:
 325                 case GEN_SUBRNG:
 326                 case GEN_SUBRNG1:
 327                 case GEN_SUBRNG2:
 328                 case GEN_SUBRNG3:
 329                 case GEN_SUBRNG4:
 330                 case GEN_SUBRNG5:
 331                 case GEN_SUBRNG6:
 332                 case GEN_SUBRNG7:
 333                 default:
 334                         signo = SIGTRAP;
 335                         code = __SI_FAULT;
 336                         break;
 337                 }
 338
 339                 info.si_signo = signo;
 340                 info.si_errno = 0;
 341                 info.si_code = code;
 342                 info.si_addr = (void __user *) regs->pc;
 343                 send_sig_info(signo, &info, current);
 344                 return;
 345
 346               case 4: /* opDEC */
 347                 if (implver() == IMPLVER_EV4) {
 348                         long si_code;
 349
 350                         /* The some versions of SRM do not handle
 351                            the opDEC properly - they return the PC of the
 352                            opDEC fault, not the instruction after as the
 353                            Alpha architecture requires.  Here we fix it up.
 354                            We do this by intentionally causing an opDEC
 355                            fault during the boot sequence and testing if
 356                            we get the correct PC.  If not, we set a flag
 357                            to correct it every time through.  */
 358                         regs->pc += opDEC_fix;
 359
 360                         /* EV4 does not implement anything except normal
 361                            rounding.  Everything else will come here as
 362                            an illegal instruction.  Emulate them.  */
 363                         si_code = alpha_fp_emul(regs->pc - 4);
 364                         if (si_code == 0)
 365                                 return;
 366                         if (si_code > 0) {
 367                                 info.si_signo = SIGFPE;
 368                                 info.si_errno = 0;
 369                                 info.si_code = si_code;
 370                                 info.si_addr = (void __user *) regs->pc;
 371                                 send_sig_info(SIGFPE, &info, current);
 372                                 return;
 373                         }
 374                 }
 375                 break;
 376
 377               case 3: /* FEN fault */
 378                 /* Irritating users can call PAL_clrfen to disable the
 379                    FPU for the process.  The kernel will then trap in
 380                    do_switch_stack and undo_switch_stack when we try
 381                    to save and restore the FP registers.
 382
 383                    Given that GCC by default generates code that uses the
 384                    FP registers, PAL_clrfen is not useful except for DoS
 385                    attacks.  So turn the bleeding FPU back on and be done
 386                    with it.  */
 387                 current_thread_info()->pcb.flags |= 1;
 388                 __reload_thread(&current_thread_info()->pcb);
 389                 return;
 390
 391               case 5: /* illoc */
 392               default: /* unexpected instruction-fault type */
 393                       ;
 394         }
 395
 396         info.si_signo = SIGILL;
 397         info.si_errno = 0;
 398         info.si_code = ILL_ILLOPC;
 399         info.si_addr = (void __user *) regs->pc;
 400         send_sig_info(SIGILL, &info, current);
 401 }
 402
 403 /* There is an ifdef in the PALcode in MILO that enables a
 404    "kernel debugging entry point" as an unprivileged call_pal.
 405
 406    We don't want to have anything to do with it, but unfortunately
 407    several versions of MILO included in distributions have it enabled,
 408    and if we don't put something on the entry point we'll oops.  */
 409
 410 asmlinkage void
 411 do_entDbg(struct pt_regs *regs)
 412 {
 413         siginfo_t info;
 414
 415         die_if_kernel("Instruction fault", regs, 0, NULL);
 416
 417         info.si_signo = SIGILL;
 418         info.si_errno = 0;
 419         info.si_code = ILL_ILLOPC;
 420         info.si_addr = (void __user *) regs->pc;
 421         force_sig_info(SIGILL, &info, current);
 422 }
 423
 424
 425 /*
 426  * entUna has a different register layout to be reasonably simple. It
 427  * needs access to all the integer registers (the kernel doesn't use
 428  * fp-regs), and it needs to have them in order for simpler access.
 429  *
 430  * Due to the non-standard register layout (and because we don't want
 431  * to handle floating-point regs), user-mode unaligned accesses are
 432  * handled separately by do_entUnaUser below.
 433  *
 434  * Oh, btw, we don't handle the "gp" register correctly, but if we fault
 435  * on a gp-register unaligned load/store, something is _very_ wrong
 436  * in the kernel anyway..
 437  */
 438 struct allregs {
 439         unsigned long regs[32];
 440         unsigned long ps, pc, gp, a0, a1, a2;
 441 };
 442
 443 struct unaligned_stat {
 444         unsigned long count, va, pc;
 445 } unaligned[2];
 446
 447
 448 /* Macro for exception fixup code to access integer registers.  */
 449 #define una_reg(r)  (regs->regs[(r) >= 16 && (r) <= 18 ? (r)+19 : (r)])
 450
 451
 452 asmlinkage void
 453 do_entUna(void * va, unsigned long opcode, unsigned long reg,
 454           struct allregs *regs)
 455 {
 456         long error, tmp1, tmp2, tmp3, tmp4;
 457         unsigned long pc = regs->pc - 4;
 458         const struct exception_table_entry *fixup;
 459
 460         unaligned[0].count++;
 461         unaligned[0].va = (unsigned long) va;
 462         unaligned[0].pc = pc;
 463
 464         /* We don't want to use the generic get/put unaligned macros as
 465            we want to trap exceptions.  Only if we actually get an
 466            exception will we decide whether we should have caught it.  */
 467
 468         switch (opcode) {
 469         case 0x0c: /* ldwu */
 470                 __asm__ __volatile__(
 471                 "1:     ldq_u %1,0(%3)\n"
 472                 "2:     ldq_u %2,1(%3)\n"
 473                 "       extwl %1,%3,%1\n"
 474                 "       extwh %2,%3,%2\n"
 475                 "3:\n"
 476                 ".section __ex_table,\"a\"\n"
 477                 "       .long 1b - .\n"
 478                 "       lda %1,3b-1b(%0)\n"
 479                 "       .long 2b - .\n"
 480                 "       lda %2,3b-2b(%0)\n"
 481                 ".previous"
 482                         : "=r"(error), "=&r"(tmp1), "=&r"(tmp2)
 483                         : "r"(va), "0"(0));
 484                 if (error)
 485                         goto got_exception;
 486                 una_reg(reg) = tmp1|tmp2;
 487                 return;
 488
 489         case 0x28: /* ldl */
 490                 __asm__ __volatile__(
 491                 "1:     ldq_u %1,0(%3)\n"
 492                 "2:     ldq_u %2,3(%3)\n"
 493                 "       extll %1,%3,%1\n"
 494                 "       extlh %2,%3,%2\n"
 495                 "3:\n"
 496                 ".section __ex_table,\"a\"\n"
 497                 "       .long 1b - .\n"
 498                 "       lda %1,3b-1b(%0)\n"
 499                 "       .long 2b - .\n"
 500                 "       lda %2,3b-2b(%0)\n"
 501                 ".previous"
 502                         : "=r"(error), "=&r"(tmp1), "=&r"(tmp2)
 503                         : "r"(va), "0"(0));
 504                 if (error)
 505                         goto got_exception;
 506                 una_reg(reg) = (int)(tmp1|tmp2);
 507                 return;
 508
 509         case 0x29: /* ldq */
 510                 __asm__ __volatile__(
 511                 "1:     ldq_u %1,0(%3)\n"
 512                 "2:     ldq_u %2,7(%3)\n"
 513                 "       extql %1,%3,%1\n"
 514                 "       extqh %2,%3,%2\n"
 515                 "3:\n"
 516                 ".section __ex_table,\"a\"\n"
 517                 "       .long 1b - .\n"
 518                 "       lda %1,3b-1b(%0)\n"
 519                 "       .long 2b - .\n"
 520                 "       lda %2,3b-2b(%0)\n"
 521                 ".previous"
 522                         : "=r"(error), "=&r"(tmp1), "=&r"(tmp2)
 523                         : "r"(va), "0"(0));
 524                 if (error)
 525                         goto got_exception;
 526                 una_reg(reg) = tmp1|tmp2;
 527                 return;
 528
 529         /* Note that the store sequences do not indicate that they change
 530            memory because it _should_ be affecting nothing in this context.
 531            (Otherwise we have other, much larger, problems.)  */
 532         case 0x0d: /* stw */
 533                 __asm__ __volatile__(
 534                 "1:     ldq_u %2,1(%5)\n"
 535                 "2:     ldq_u %1,0(%5)\n"
 536                 "       inswh %6,%5,%4\n"
 537                 "       inswl %6,%5,%3\n"
 538                 "       mskwh %2,%5,%2\n"
 539                 "       mskwl %1,%5,%1\n"
 540                 "       or %2,%4,%2\n"
 541                 "       or %1,%3,%1\n"
 542                 "3:     stq_u %2,1(%5)\n"
 543                 "4:     stq_u %1,0(%5)\n"
 544                 "5:\n"
 545                 ".section __ex_table,\"a\"\n"
 546                 "       .long 1b - .\n"
 547                 "       lda %2,5b-1b(%0)\n"
 548                 "       .long 2b - .\n"
 549                 "       lda %1,5b-2b(%0)\n"
 550                 "       .long 3b - .\n"
 551                 "       lda $31,5b-3b(%0)\n"
 552                 "       .long 4b - .\n"
 553                 "       lda $31,5b-4b(%0)\n"
 554                 ".previous"
 555                         : "=r"(error), "=&r"(tmp1), "=&r"(tmp2),
 556                           "=&r"(tmp3), "=&r"(tmp4)
 557                         : "r"(va), "r"(una_reg(reg)), "0"(0));
 558                 if (error)
 559                         goto got_exception;
 560                 return;
 561
 562         case 0x2c: /* stl */
 563                 __asm__ __volatile__(
 564                 "1:     ldq_u %2,3(%5)\n"
 565                 "2:     ldq_u %1,0(%5)\n"
 566                 "       inslh %6,%5,%4\n"
 567                 "       insll %6,%5,%3\n"
 568                 "       msklh %2,%5,%2\n"
 569                 "       mskll %1,%5,%1\n"
 570                 "       or %2,%4,%2\n"
 571                 "       or %1,%3,%1\n"
 572                 "3:     stq_u %2,3(%5)\n"
 573                 "4:     stq_u %1,0(%5)\n"
 574                 "5:\n"
 575                 ".section __ex_table,\"a\"\n"
 576                 "       .long 1b - .\n"
 577                 "       lda %2,5b-1b(%0)\n"
 578                 "       .long 2b - .\n"
 579                 "       lda %1,5b-2b(%0)\n"
 580                 "       .long 3b - .\n"
 581                 "       lda $31,5b-3b(%0)\n"
 582                 "       .long 4b - .\n"
 583                 "       lda $31,5b-4b(%0)\n"
 584                 ".previous"
 585                         : "=r"(error), "=&r"(tmp1), "=&r"(tmp2),
 586                           "=&r"(tmp3), "=&r"(tmp4)
 587                         : "r"(va), "r"(una_reg(reg)), "0"(0));
 588                 if (error)
 589                         goto got_exception;
 590                 return;
 591
 592         case 0x2d: /* stq */
 593                 __asm__ __volatile__(
 594                 "1:     ldq_u %2,7(%5)\n"
 595                 "2:     ldq_u %1,0(%5)\n"
 596                 "       insqh %6,%5,%4\n"
 597                 "       insql %6,%5,%3\n"
 598                 "       mskqh %2,%5,%2\n"
 599                 "       mskql %1,%5,%1\n"
 600                 "       or %2,%4,%2\n"
 601                 "       or %1,%3,%1\n"
 602                 "3:     stq_u %2,7(%5)\n"
 603                 "4:     stq_u %1,0(%5)\n"
 604                 "5:\n"
 605                 ".section __ex_table,\"a\"\n\t"
 606                 "       .long 1b - .\n"
 607                 "       lda %2,5b-1b(%0)\n"
 608                 "       .long 2b - .\n"
 609                 "       lda %1,5b-2b(%0)\n"
 610                 "       .long 3b - .\n"
 611                 "       lda $31,5b-3b(%0)\n"
 612                 "       .long 4b - .\n"
 613                 "       lda $31,5b-4b(%0)\n"
 614                 ".previous"
 615                         : "=r"(error), "=&r"(tmp1), "=&r"(tmp2),
 616                           "=&r"(tmp3), "=&r"(tmp4)
 617                         : "r"(va), "r"(una_reg(reg)), "0"(0));
 618                 if (error)
 619                         goto got_exception;
 620                 return;
 621         }
 622
 623         lock_kernel();
 624         printk("Bad unaligned kernel access at %016lx: %p %lx %ld\n",
 625                 pc, va, opcode, reg);
 626         do_exit(SIGSEGV);
 627
 628 got_exception:
 629         /* Ok, we caught the exception, but we don't want it.  Is there
 630            someone to pass it along to?  */
 631         if ((fixup = search_exception_tables(pc)) != 0) {
 632                 unsigned long newpc;
 633                 newpc = fixup_exception(una_reg, fixup, pc);
 634
 635                 printk("Forwarding unaligned exception at %lx (%lx)\n",
 636                        pc, newpc);
 637
 638                 regs->pc = newpc;
 639                 return;
 640         }
 641
 642         /*
 643          * Yikes!  No one to forward the exception to.
 644          * Since the registers are in a weird format, dump them ourselves.
 645          */
 646         lock_kernel();
 647
 648         printk("%s(%d): unhandled unaligned exception\n",
 649                current->comm, task_pid_nr(current));
 650
 651         printk("pc = [<%016lx>]  ra = [<%016lx>]  ps = %04lx\n",
 652                pc, una_reg(26), regs->ps);
 653         printk("r0 = %016lx  r1 = %016lx  r2 = %016lx\n",
 654                una_reg(0), una_reg(1), una_reg(2));
 655         printk("r3 = %016lx  r4 = %016lx  r5 = %016lx\n",
 656                una_reg(3), una_reg(4), una_reg(5));
 657         printk("r6 = %016lx  r7 = %016lx  r8 = %016lx\n",
 658                una_reg(6), una_reg(7), una_reg(8));
 659         printk("r9 = %016lx  r10= %016lx  r11= %016lx\n",
 660                una_reg(9), una_reg(10), una_reg(11));
 661         printk("r12= %016lx  r13= %016lx  r14= %016lx\n",
 662                una_reg(12), una_reg(13), una_reg(14));
 663         printk("r15= %016lx\n", una_reg(15));
 664         printk("r16= %016lx  r17= %016lx  r18= %016lx\n",
 665                una_reg(16), una_reg(17), una_reg(18));
 666         printk("r19= %016lx  r20= %016lx  r21= %016lx\n",
 667                una_reg(19), una_reg(20), una_reg(21));
 668         printk("r22= %016lx  r23= %016lx  r24= %016lx\n",
 669                una_reg(22), una_reg(23), una_reg(24));
 670         printk("r25= %016lx  r27= %016lx  r28= %016lx\n",
 671                una_reg(25), una_reg(27), una_reg(28));
 672         printk("gp = %016lx  sp = %p\n", regs->gp, regs+1);
 673
 674         dik_show_code((unsigned int *)pc);
 675         dik_show_trace((unsigned long *)(regs+1));
 676
 677         if (test_and_set_thread_flag (TIF_DIE_IF_KERNEL)) {
 678                 printk("die_if_kernel recursion detected.\n");
 679                 local_irq_enable();
 680                 while (1);
 681         }
 682         do_exit(SIGSEGV);
 683 }
 684
 685 /*
 686  * Convert an s-floating point value in memory format to the
 687  * corresponding value in register format.  The exponent
 688  * needs to be remapped to preserve non-finite values
 689  * (infinities, not-a-numbers, denormals).
 690  */
 691 static inline unsigned long
 692 s_mem_to_reg (unsigned long s_mem)
 693 {
 694         unsigned long frac    = (s_mem >>  0) & 0x7fffff;
 695         unsigned long sign    = (s_mem >> 31) & 0x1;
 696         unsigned long exp_msb = (s_mem >> 30) & 0x1;
 697         unsigned long exp_low = (s_mem >> 23) & 0x7f;
 698         unsigned long exp;
 699
 700         exp = (exp_msb << 10) | exp_low;        /* common case */
 701         if (exp_msb) {
 702                 if (exp_low == 0x7f) {
 703                         exp = 0x7ff;
 704                 }
 705         } else {
 706                 if (exp_low == 0x00) {
 707                         exp = 0x000;
 708                 } else {
 709                         exp |= (0x7 << 7);
 710                 }
 711         }
 712         return (sign << 63) | (exp << 52) | (frac << 29);
 713 }
 714
 715 /*
 716  * Convert an s-floating point value in register format to the
 717  * corresponding value in memory format.
 718  */
 719 static inline unsigned long
 720 s_reg_to_mem (unsigned long s_reg)
 721 {
 722         return ((s_reg >> 62) << 30) | ((s_reg << 5) >> 34);
 723 }
 724
 725 /*
 726  * Handle user-level unaligned fault.  Handling user-level unaligned
 727  * faults is *extremely* slow and produces nasty messages.  A user
 728  * program *should* fix unaligned faults ASAP.
 729  *
 730  * Notice that we have (almost) the regular kernel stack layout here,
 731  * so finding the appropriate registers is a little more difficult
 732  * than in the kernel case.
 733  *
 734  * Finally, we handle regular integer load/stores only.  In
 735  * particular, load-linked/store-conditionally and floating point
 736  * load/stores are not supported.  The former make no sense with
 737  * unaligned faults (they are guaranteed to fail) and I don't think
 738  * the latter will occur in any decent program.
 739  *
 740  * Sigh. We *do* have to handle some FP operations, because GCC will
 741  * uses them as temporary storage for integer memory to memory copies.
 742  * However, we need to deal with stt/ldt and sts/lds only.
 743  */
 744
 745 #define OP_INT_MASK     ( 1L << 0x28 | 1L << 0x2c   /* ldl stl */       \
 746                         | 1L << 0x29 | 1L << 0x2d   /* ldq stq */       \
 747                         | 1L << 0x0c | 1L << 0x0d   /* ldwu stw */      \
 748                         | 1L << 0x0a | 1L << 0x0e ) /* ldbu stb */
 749
 750 #define OP_WRITE_MASK   ( 1L << 0x26 | 1L << 0x27   /* sts stt */       \
 751                         | 1L << 0x2c | 1L << 0x2d   /* stl stq */       \
 752                         | 1L << 0x0d | 1L << 0x0e ) /* stw stb */
 753
 754 #define R(x)    ((size_t) &((struct pt_regs *)0)->x)
 755
 756 static int unauser_reg_offsets[32] = {
 757         R(r0), R(r1), R(r2), R(r3), R(r4), R(r5), R(r6), R(r7), R(r8),
 758         /* r9 ... r15 are stored in front of regs.  */
 759         -56, -48, -40, -32, -24, -16, -8,
 760         R(r16), R(r17), R(r18),
 761         R(r19), R(r20), R(r21), R(r22), R(r23), R(r24), R(r25), R(r26),
 762         R(r27), R(r28), R(gp),
 763         0, 0
 764 };
 765
 766 #undef R
 767
 768 asmlinkage void
 769 do_entUnaUser(void __user * va, unsigned long opcode,
 770               unsigned long reg, struct pt_regs *regs)
 771 {
 772         static int cnt = 0;
 773         static long last_time = 0;
 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 (cnt >= 5 && jiffies - last_time > 5*HZ) {
 785                         cnt = 0;
 786                 }
 787                 if (++cnt < 5) {
 788                         printk("%s(%d): unaligned trap at %016lx: %p %lx %ld\n",
 789                                current->comm, task_pid_nr(current),
 790                                regs->pc - 4, va, opcode, reg);
 791                 }
 792                 last_time = jiffies;
 793         }
 794         if (test_thread_flag (TIF_UAC_SIGBUS))
 795                 goto give_sigbus;
 796         /* Not sure why you'd want to use this, but... */
 797         if (test_thread_flag (TIF_UAC_NOFIX))
 798                 return;
 799
 800         /* Don't bother reading ds in the access check since we already
 801            know that this came from the user.  Also rely on the fact that
 802            the page at TASK_SIZE is unmapped and so can't be touched anyway. */
 803         if (!__access_ok((unsigned long)va, 0, USER_DS))
 804                 goto give_sigsegv;
 805
 806         ++unaligned[1].count;
 807         unaligned[1].va = (unsigned long)va;
 808         unaligned[1].pc = regs->pc - 4;
 809
 810         if ((1L << opcode) & OP_INT_MASK) {
 811                 /* it's an integer load/store */
 812                 if (reg < 30) {
 813                         reg_addr = (unsigned long *)
 814                           ((char *)regs + unauser_reg_offsets[reg]);
 815                 } else if (reg == 30) {
 816                         /* usp in PAL regs */
 817                         fake_reg = rdusp();
 818                 } else {
 819                         /* zero "register" */
 820                         fake_reg = 0;
 821                 }
 822         }
 823
 824         /* We don't want to use the generic get/put unaligned macros as
 825            we want to trap exceptions.  Only if we actually get an
 826            exception will we decide whether we should have caught it.  */
 827
 828         switch (opcode) {
 829         case 0x0c: /* ldwu */
 830                 __asm__ __volatile__(
 831                 "1:     ldq_u %1,0(%3)\n"
 832                 "2:     ldq_u %2,1(%3)\n"
 833                 "       extwl %1,%3,%1\n"
 834                 "       extwh %2,%3,%2\n"
 835                 "3:\n"
 836                 ".section __ex_table,\"a\"\n"
 837                 "       .long 1b - .\n"
 838                 "       lda %1,3b-1b(%0)\n"
 839                 "       .long 2b - .\n"
 840                 "       lda %2,3b-2b(%0)\n"
 841                 ".previous"
 842                         : "=r"(error), "=&r"(tmp1), "=&r"(tmp2)
 843                         : "r"(va), "0"(0));
 844                 if (error)
 845                         goto give_sigsegv;
 846                 *reg_addr = tmp1|tmp2;
 847                 break;
 848
 849         case 0x22: /* lds */
 850                 __asm__ __volatile__(
 851                 "1:     ldq_u %1,0(%3)\n"
 852                 "2:     ldq_u %2,3(%3)\n"
 853                 "       extll %1,%3,%1\n"
 854                 "       extlh %2,%3,%2\n"
 855                 "3:\n"
 856                 ".section __ex_table,\"a\"\n"
 857                 "       .long 1b - .\n"
 858                 "       lda %1,3b-1b(%0)\n"
 859                 "       .long 2b - .\n"
 860                 "       lda %2,3b-2b(%0)\n"
 861                 ".previous"
 862                         : "=r"(error), "=&r"(tmp1), "=&r"(tmp2)
 863                         : "r"(va), "0"(0));
 864                 if (error)
 865                         goto give_sigsegv;
 866                 alpha_write_fp_reg(reg, s_mem_to_reg((int)(tmp1|tmp2)));
 867                 return;
 868
 869         case 0x23: /* ldt */
 870                 __asm__ __volatile__(
 871                 "1:     ldq_u %1,0(%3)\n"
 872                 "2:     ldq_u %2,7(%3)\n"
 873                 "       extql %1,%3,%1\n"
 874                 "       extqh %2,%3,%2\n"
 875                 "3:\n"
 876                 ".section __ex_table,\"a\"\n"
 877                 "       .long 1b - .\n"
 878                 "       lda %1,3b-1b(%0)\n"
 879                 "       .long 2b - .\n"
 880                 "       lda %2,3b-2b(%0)\n"
 881                 ".previous"
 882                         : "=r"(error), "=&r"(tmp1), "=&r"(tmp2)
 883                         : "r"(va), "0"(0));
 884                 if (error)
 885                         goto give_sigsegv;
 886                 alpha_write_fp_reg(reg, tmp1|tmp2);
 887                 return;
 888
 889         case 0x28: /* ldl */
 890                 __asm__ __volatile__(
 891                 "1:     ldq_u %1,0(%3)\n"
 892                 "2:     ldq_u %2,3(%3)\n"
 893                 "       extll %1,%3,%1\n"
 894                 "       extlh %2,%3,%2\n"
 895                 "3:\n"
 896                 ".section __ex_table,\"a\"\n"
 897                 "       .long 1b - .\n"
 898                 "       lda %1,3b-1b(%0)\n"
 899                 "       .long 2b - .\n"
 900                 "       lda %2,3b-2b(%0)\n"
 901                 ".previous"
 902                         : "=r"(error), "=&r"(tmp1), "=&r"(tmp2)
 903                         : "r"(va), "0"(0));
 904                 if (error)
 905                         goto give_sigsegv;
 906                 *reg_addr = (int)(tmp1|tmp2);
 907                 break;
 908
 909         case 0x29: /* ldq */
 910                 __asm__ __volatile__(
 911                 "1:     ldq_u %1,0(%3)\n"
 912                 "2:     ldq_u %2,7(%3)\n"
 913                 "       extql %1,%3,%1\n"
 914                 "       extqh %2,%3,%2\n"
 915                 "3:\n"
 916                 ".section __ex_table,\"a\"\n"
 917                 "       .long 1b - .\n"
 918                 "       lda %1,3b-1b(%0)\n"
 919                 "       .long 2b - .\n"
 920                 "       lda %2,3b-2b(%0)\n"
 921                 ".previous"
 922                         : "=r"(error), "=&r"(tmp1), "=&r"(tmp2)
 923                         : "r"(va), "0"(0));
 924                 if (error)
 925                         goto give_sigsegv;
 926                 *reg_addr = tmp1|tmp2;
 927                 break;
 928
 929         /* Note that the store sequences do not indicate that they change
 930            memory because it _should_ be affecting nothing in this context.
 931            (Otherwise we have other, much larger, problems.)  */
 932         case 0x0d: /* stw */
 933                 __asm__ __volatile__(
 934                 "1:     ldq_u %2,1(%5)\n"
 935                 "2:     ldq_u %1,0(%5)\n"
 936                 "       inswh %6,%5,%4\n"
 937                 "       inswl %6,%5,%3\n"
 938                 "       mskwh %2,%5,%2\n"
 939                 "       mskwl %1,%5,%1\n"
 940                 "       or %2,%4,%2\n"
 941                 "       or %1,%3,%1\n"
 942                 "3:     stq_u %2,1(%5)\n"
 943                 "4:     stq_u %1,0(%5)\n"
 944                 "5:\n"
 945                 ".section __ex_table,\"a\"\n"
 946                 "       .long 1b - .\n"
 947                 "       lda %2,5b-1b(%0)\n"
 948                 "       .long 2b - .\n"
 949                 "       lda %1,5b-2b(%0)\n"
 950                 "       .long 3b - .\n"
 951                 "       lda $31,5b-3b(%0)\n"
 952                 "       .long 4b - .\n"
 953                 "       lda $31,5b-4b(%0)\n"
 954                 ".previous"
 955                         : "=r"(error), "=&r"(tmp1), "=&r"(tmp2),
 956                           "=&r"(tmp3), "=&r"(tmp4)
 957                         : "r"(va), "r"(*reg_addr), "0"(0));
 958                 if (error)
 959                         goto give_sigsegv;
 960                 return;
 961
 962         case 0x26: /* sts */
 963                 fake_reg = s_reg_to_mem(alpha_read_fp_reg(reg));
 964                 /* FALLTHRU */
 965
 966         case 0x2c: /* stl */
 967                 __asm__ __volatile__(
 968                 "1:     ldq_u %2,3(%5)\n"
 969                 "2:     ldq_u %1,0(%5)\n"
 970                 "       inslh %6,%5,%4\n"
 971                 "       insll %6,%5,%3\n"
 972                 "       msklh %2,%5,%2\n"
 973                 "       mskll %1,%5,%1\n"
 974                 "       or %2,%4,%2\n"
 975                 "       or %1,%3,%1\n"
 976                 "3:     stq_u %2,3(%5)\n"
 977                 "4:     stq_u %1,0(%5)\n"
 978                 "5:\n"
 979                 ".section __ex_table,\"a\"\n"
 980                 "       .long 1b - .\n"
 981                 "       lda %2,5b-1b(%0)\n"
 982                 "       .long 2b - .\n"
 983                 "       lda %1,5b-2b(%0)\n"
 984                 "       .long 3b - .\n"
 985                 "       lda $31,5b-3b(%0)\n"
 986                 "       .long 4b - .\n"
 987                 "       lda $31,5b-4b(%0)\n"
 988                 ".previous"
 989                         : "=r"(error), "=&r"(tmp1), "=&r"(tmp2),
 990                           "=&r"(tmp3), "=&r"(tmp4)
 991                         : "r"(va), "r"(*reg_addr), "0"(0));
 992                 if (error)
 993                         goto give_sigsegv;
 994                 return;
 995
 996         case 0x27: /* stt */
 997                 fake_reg = alpha_read_fp_reg(reg);
 998                 /* FALLTHRU */
 999
1000         case 0x2d: /* stq */
1001                 __asm__ __volatile__(
1002                 "1:     ldq_u %2,7(%5)\n"
1003                 "2:     ldq_u %1,0(%5)\n"
1004                 "       insqh %6,%5,%4\n"
1005                 "       insql %6,%5,%3\n"
1006                 "       mskqh %2,%5,%2\n"
1007                 "       mskql %1,%5,%1\n"
1008                 "       or %2,%4,%2\n"
1009                 "       or %1,%3,%1\n"
1010                 "3:     stq_u %2,7(%5)\n"
1011                 "4:     stq_u %1,0(%5)\n"
1012                 "5:\n"
1013                 ".section __ex_table,\"a\"\n\t"
1014                 "       .long 1b - .\n"
1015                 "       lda %2,5b-1b(%0)\n"
1016                 "       .long 2b - .\n"
1017                 "       lda %1,5b-2b(%0)\n"
1018                 "       .long 3b - .\n"
1019                 "       lda $31,5b-3b(%0)\n"
1020                 "       .long 4b - .\n"
1021                 "       lda $31,5b-4b(%0)\n"
1022                 ".previous"
1023                         : "=r"(error), "=&r"(tmp1), "=&r"(tmp2),
1024                           "=&r"(tmp3), "=&r"(tmp4)
1025                         : "r"(va), "r"(*reg_addr), "0"(0));
1026                 if (error)
1027                         goto give_sigsegv;
1028                 return;
1029
1030         default:
1031                 /* What instruction were you trying to use, exactly?  */
1032                 goto give_sigbus;
1033         }
1034
1035         /* Only integer loads should get here; everyone else returns early. */
1036         if (reg == 30)
1037                 wrusp(fake_reg);
1038         return;
1039
1040 give_sigsegv:
1041         regs->pc -= 4;  /* make pc point to faulting insn */
1042         info.si_signo = SIGSEGV;
1043         info.si_errno = 0;
1044
1045         /* We need to replicate some of the logic in mm/fault.c,
1046            since we don't have access to the fault code in the
1047            exception handling return path.  */
1048         if (!__access_ok((unsigned long)va, 0, USER_DS))
1049                 info.si_code = SEGV_ACCERR;
1050         else {
1051                 struct mm_struct *mm = current->mm;
1052                 down_read(&mm->mmap_sem);
1053                 if (find_vma(mm, (unsigned long)va))
1054                         info.si_code = SEGV_ACCERR;
1055                 else
1056                         info.si_code = SEGV_MAPERR;
1057                 up_read(&mm->mmap_sem);
1058         }
1059         info.si_addr = va;
1060         send_sig_info(SIGSEGV, &info, current);
1061         return;
1062
1063 give_sigbus:
1064         regs->pc -= 4;
1065         info.si_signo = SIGBUS;
1066         info.si_errno = 0;
1067         info.si_code = BUS_ADRALN;
1068         info.si_addr = va;
1069         send_sig_info(SIGBUS, &info, current);
1070         return;
1071 }
1072
1073 void __init
1074 trap_init(void)
1075 {
1076         /* Tell PAL-code what global pointer we want in the kernel.  */
1077         register unsigned long gptr __asm__("$29");
1078         wrkgp(gptr);
1079
1080         /* Hack for Multia (UDB) and JENSEN: some of their SRMs have
1081            a bug in the handling of the opDEC fault.  Fix it up if so.  */
1082         if (implver() == IMPLVER_EV4)
1083                 opDEC_check();
1084
1085         wrent(entArith, 1);
1086         wrent(entMM, 2);
1087         wrent(entIF, 3);
1088         wrent(entUna, 4);
1089         wrent(entSys, 5);
1090         wrent(entDbg, 6);
1091 }