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/smp_lock.h>
  17 #include <linux/module.h>
  18 #include <linux/init.h>
  19 #include <linux/kallsyms.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
  28 #include "proto.h"
  29
  30 /* Work-around for some SRMs which mishandle opDEC faults.  */
  31
  32 static int opDEC_fix;
  33
  34 static void __init
  35 opDEC_check(void)
  36 {
  37         __asm__ __volatile__ (
  38         /* Load the address of... */
  39         "       br      $16, 1f\n"
  40         /* A stub instruction fault handler.  Just add 4 to the
  41            pc and continue.  */
  42         "       ldq     $16, 8($sp)\n"
  43         "       addq    $16, 4, $16\n"
  44         "       stq     $16, 8($sp)\n"
  45         "       call_pal %[rti]\n"
  46         /* Install the instruction fault handler.  */
  47         "1:     lda     $17, 3\n"
  48         "       call_pal %[wrent]\n"
  49         /* With that in place, the fault from the round-to-minf fp
  50            insn will arrive either at the "lda 4" insn (bad) or one
  51            past that (good).  This places the correct fixup in %0.  */
  52         "       lda %[fix], 0\n"
  53         "       cvttq/svm $f31,$f31\n"
  54         "       lda %[fix], 4"
  55         : [fix] "=r" (opDEC_fix)
  56         : [rti] "n" (PAL_rti), [wrent] "n" (PAL_wrent)
  57         : "$0", "$1", "$16", "$17", "$22", "$23", "$24", "$25");
  58
  59         if (opDEC_fix)
  60                 printk("opDEC fixup enabled.\n");
  61 }
  62
  63 void
  64 dik_show_regs(struct pt_regs *regs, unsigned long *r9_15)
  65 {
  66         printk("pc = [<%016lx>]  ra = [<%016lx>]  ps = %04lx    %s\n",
  67                regs->pc, regs->r26, regs->ps, print_tainted());
  68         print_symbol("pc is at %s\n", regs->pc);
  69         print_symbol("ra is at %s\n", regs->r26 );
  70         printk("v0 = %016lx  t0 = %016lx  t1 = %016lx\n",
  71                regs->r0, regs->r1, regs->r2);
  72         printk("t2 = %016lx  t3 = %016lx  t4 = %016lx\n",
  73                regs->r3, regs->r4, regs->r5);
  74         printk("t5 = %016lx  t6 = %016lx  t7 = %016lx\n",
  75                regs->r6, regs->r7, regs->r8);
  76
  77         if (r9_15) {
  78                 printk("s0 = %016lx  s1 = %016lx  s2 = %016lx\n",
  79                        r9_15[9], r9_15[10], r9_15[11]);
  80                 printk("s3 = %016lx  s4 = %016lx  s5 = %016lx\n",
  81                        r9_15[12], r9_15[13], r9_15[14]);
  82                 printk("s6 = %016lx\n", r9_15[15]);
  83         }
  84
  85         printk("a0 = %016lx  a1 = %016lx  a2 = %016lx\n",
  86                regs->r16, regs->r17, regs->r18);
  87         printk("a3 = %016lx  a4 = %016lx  a5 = %016lx\n",
  88                regs->r19, regs->r20, regs->r21);
  89         printk("t8 = %016lx  t9 = %016lx  t10= %016lx\n",
  90                regs->r22, regs->r23, regs->r24);
  91         printk("t11= %016lx  pv = %016lx  at = %016lx\n",
  92                regs->r25, regs->r27, regs->r28);
  93         printk("gp = %016lx  sp = %p\n", regs->gp, regs+1);
  94 #if 0
  95 __halt();
  96 #endif
  97 }
  98
  99 #if 0
 100 static char * ireg_name[] = {"v0", "t0", "t1", "t2", "t3", "t4", "t5", "t6",
 101                            "t7", "s0", "s1", "s2", "s3", "s4", "s5", "s6",
 102                            "a0", "a1", "a2", "a3", "a4", "a5", "t8", "t9",
 103                            "t10", "t11", "ra", "pv", "at", "gp", "sp", "zero"};
 104 #endif
 105
 106 static void
 107 dik_show_code(unsigned int *pc)
 108 {
 109         long i;
 110
 111         printk("Code:");
 112         for (i = -6; i < 2; i++) {
 113                 unsigned int insn;
 114                 if (__get_user(insn, (unsigned int __user *)pc + i))
 115                         break;
 116                 printk("%c%08x%c", i ? ' ' : '<', insn, i ? ' ' : '>');
 117         }
 118         printk("\n");
 119 }
 120
 121 static void
 122 dik_show_trace(unsigned long *sp)
 123 {
 124         long i = 0;
 125         printk("Trace:\n");
 126         while (0x1ff8 & (unsigned long) sp) {
 127                 extern char _stext[], _etext[];
 128                 unsigned long tmp = *sp;
 129                 sp++;
 130                 if (tmp < (unsigned long) &_stext)
 131                         continue;
 132                 if (tmp >= (unsigned long) &_etext)
 133                         continue;
 134                 printk("[<%lx>]", tmp);
 135                 print_symbol(" %s", tmp);
 136                 printk("\n");
 137                 if (i > 40) {
 138                         printk(" ...");
 139                         break;
 140                 }
 141         }
 142         printk("\n");
 143 }
 144
 145 static int kstack_depth_to_print = 24;
 146
 147 void show_stack(struct task_struct *task, unsigned long *sp)
 148 {
 149         unsigned long *stack;
 150         int i;
 151
 152         /*
 153          * debugging aid: "show_stack(NULL);" prints the
 154          * back trace for this cpu.
 155          */
 156         if(sp==NULL)
 157                 sp=(unsigned long*)&sp;
 158
 159         stack = sp;
 160         for(i=0; i < kstack_depth_to_print; i++) {
 161                 if (((long) stack & (THREAD_SIZE-1)) == 0)
 162                         break;
 163                 if (i && ((i % 4) == 0))
 164                         printk("\n       ");
 165                 printk("%016lx ", *stack++);
 166         }
 167         printk("\n");
 168         dik_show_trace(sp);
 169 }
 170
 171 void dump_stack(void)
 172 {
 173         show_stack(NULL, NULL);
 174 }
 175
 176 EXPORT_SYMBOL(dump_stack);
 177
 178 void
 179 die_if_kernel(char * str, struct pt_regs *regs, long err, unsigned long *r9_15)
 180 {
 181         if (regs->ps & 8)
 182                 return;
 183 #ifdef CONFIG_SMP
 184         printk("CPU %d ", hard_smp_processor_id());
 185 #endif
 186         printk("%s(%d): %s %ld\n", current->comm, task_pid_nr(current), str, err);
 187         dik_show_regs(regs, r9_15);
 188         add_taint(TAINT_DIE);
 189         dik_show_trace((unsigned long *)(regs+1));
 190         dik_show_code((unsigned int *)regs->pc);
 191
 192         if (test_and_set_thread_flag (TIF_DIE_IF_KERNEL)) {
 193                 printk("die_if_kernel recursion detected.\n");
 194                 local_irq_enable();
 195                 while (1);
 196         }
 197         do_exit(SIGSEGV);
 198 }
 199
 200 #ifndef CONFIG_MATHEMU
 201 static long dummy_emul(void) { return 0; }
 202 long (*alpha_fp_emul_imprecise)(struct pt_regs *regs, unsigned long writemask)
 203   = (void *)dummy_emul;
 204 long (*alpha_fp_emul) (unsigned long pc)
 205   = (void *)dummy_emul;
 206 #else
 207 long alpha_fp_emul_imprecise(struct pt_regs *regs, unsigned long writemask);
 208 long alpha_fp_emul (unsigned long pc);
 209 #endif
 210
 211 asmlinkage void
 212 do_entArith(unsigned long summary, unsigned long write_mask,
 213             struct pt_regs *regs)
 214 {
 215         long si_code = FPE_FLTINV;
 216         siginfo_t info;
 217
 218         if (summary & 1) {
 219                 /* Software-completion summary bit is set, so try to
 220                    emulate the instruction.  If the processor supports
 221                    precise exceptions, we don't have to search.  */
 222                 if (!amask(AMASK_PRECISE_TRAP))
 223                         si_code = alpha_fp_emul(regs->pc - 4);
 224                 else
 225                         si_code = alpha_fp_emul_imprecise(regs, write_mask);
 226                 if (si_code == 0)
 227                         return;
 228         }
 229         die_if_kernel("Arithmetic fault", regs, 0, NULL);
 230
 231         info.si_signo = SIGFPE;
 232         info.si_errno = 0;
 233         info.si_code = si_code;
 234         info.si_addr = (void __user *) regs->pc;
 235         send_sig_info(SIGFPE, &info, current);
 236 }
 237
 238 asmlinkage void
 239 do_entIF(unsigned long type, struct pt_regs *regs)
 240 {
 241         siginfo_t info;
 242         int signo, code;
 243
 244         if ((regs->ps & ~IPL_MAX) == 0) {
 245                 if (type == 1) {
 246                         const unsigned int *data
 247                           = (const unsigned int *) regs->pc;
 248                         printk("Kernel bug at %s:%d\n",
 249                                (const char *)(data[1] | (long)data[2] << 32),
 250                                data[0]);
 251                 }
 252                 die_if_kernel((type == 1 ? "Kernel Bug" : "Instruction fault"),
 253                               regs, type, NULL);
 254         }
 255
 256         switch (type) {
 257               case 0: /* breakpoint */
 258                 info.si_signo = SIGTRAP;
 259                 info.si_errno = 0;
 260                 info.si_code = TRAP_BRKPT;
 261                 info.si_trapno = 0;
 262                 info.si_addr = (void __user *) regs->pc;
 263
 264                 if (ptrace_cancel_bpt(current)) {
 265                         regs->pc -= 4;  /* make pc point to former bpt */
 266                 }
 267
 268                 send_sig_info(SIGTRAP, &info, current);
 269                 return;
 270
 271               case 1: /* bugcheck */
 272                 info.si_signo = SIGTRAP;
 273                 info.si_errno = 0;
 274                 info.si_code = __SI_FAULT;
 275                 info.si_addr = (void __user *) regs->pc;
 276                 info.si_trapno = 0;
 277                 send_sig_info(SIGTRAP, &info, current);
 278                 return;
 279
 280               case 2: /* gentrap */
 281                 info.si_addr = (void __user *) regs->pc;
 282                 info.si_trapno = regs->r16;
 283                 switch ((long) regs->r16) {
 284                 case GEN_INTOVF:
 285                         signo = SIGFPE;
 286                         code = FPE_INTOVF;
 287                         break;
 288                 case GEN_INTDIV:
 289                         signo = SIGFPE;
 290                         code = FPE_INTDIV;
 291                         break;
 292                 case GEN_FLTOVF:
 293                         signo = SIGFPE;
 294                         code = FPE_FLTOVF;
 295                         break;
 296                 case GEN_FLTDIV:
 297                         signo = SIGFPE;
 298                         code = FPE_FLTDIV;
 299                         break;
 300                 case GEN_FLTUND:
 301                         signo = SIGFPE;
 302                         code = FPE_FLTUND;
 303                         break;
 304                 case GEN_FLTINV:
 305                         signo = SIGFPE;
 306                         code = FPE_FLTINV;
 307                         break;
 308                 case GEN_FLTINE:
 309                         signo = SIGFPE;
 310                         code = FPE_FLTRES;
 311                         break;
 312                 case GEN_ROPRAND:
 313                         signo = SIGFPE;
 314                         code = __SI_FAULT;
 315                         break;
 316
 317                 case GEN_DECOVF:
 318                 case GEN_DECDIV:
 319                 case GEN_DECINV:
 320                 case GEN_ASSERTERR:
 321                 case GEN_NULPTRERR:
 322                 case GEN_STKOVF:
 323                 case GEN_STRLENERR:
 324                 case GEN_SUBSTRERR:
 325                 case GEN_RANGERR:
 326                 case GEN_SUBRNG:
 327                 case GEN_SUBRNG1:
 328                 case GEN_SUBRNG2:
 329                 case GEN_SUBRNG3:
 330                 case GEN_SUBRNG4:
 331                 case GEN_SUBRNG5:
 332                 case GEN_SUBRNG6:
 333                 case GEN_SUBRNG7:
 334                 default:
 335                         signo = SIGTRAP;
 336                         code = __SI_FAULT;
 337                         break;
 338                 }
 339
 340                 info.si_signo = signo;
 341                 info.si_errno = 0;
 342                 info.si_code = code;
 343                 info.si_addr = (void __user *) regs->pc;
 344                 send_sig_info(signo, &info, current);
 345                 return;
 346
 347               case 4: /* opDEC */
 348                 if (implver() == IMPLVER_EV4) {
 349                         long si_code;
 350
 351                         /* The some versions of SRM do not handle
 352                            the opDEC properly - they return the PC of the
 353                            opDEC fault, not the instruction after as the
 354                            Alpha architecture requires.  Here we fix it up.
 355                            We do this by intentionally causing an opDEC
 356                            fault during the boot sequence and testing if
 357                            we get the correct PC.  If not, we set a flag
 358                            to correct it every time through.  */
 359                         regs->pc += opDEC_fix;
 360
 361                         /* EV4 does not implement anything except normal
 362                            rounding.  Everything else will come here as
 363                            an illegal instruction.  Emulate them.  */
 364                         si_code = alpha_fp_emul(regs->pc - 4);
 365                         if (si_code == 0)
 366                                 return;
 367                         if (si_code > 0) {
 368                                 info.si_signo = SIGFPE;
 369                                 info.si_errno = 0;
 370                                 info.si_code = si_code;
 371                                 info.si_addr = (void __user *) regs->pc;
 372                                 send_sig_info(SIGFPE, &info, current);
 373                                 return;
 374                         }
 375                 }
 376                 break;
 377
 378               case 3: /* FEN fault */
 379                 /* Irritating users can call PAL_clrfen to disable the
 380                    FPU for the process.  The kernel will then trap in
 381                    do_switch_stack and undo_switch_stack when we try
 382                    to save and restore the FP registers.
 383
 384                    Given that GCC by default generates code that uses the
 385                    FP registers, PAL_clrfen is not useful except for DoS
 386                    attacks.  So turn the bleeding FPU back on and be done
 387                    with it.  */
 388                 current_thread_info()->pcb.flags |= 1;
 389                 __reload_thread(&current_thread_info()->pcb);
 390                 return;
 391
 392               case 5: /* illoc */
 393               default: /* unexpected instruction-fault type */
 394                       ;
 395         }
 396
 397         info.si_signo = SIGILL;
 398         info.si_errno = 0;
 399         info.si_code = ILL_ILLOPC;
 400         info.si_addr = (void __user *) regs->pc;
 401         send_sig_info(SIGILL, &info, current);
 402 }
 403
 404 /* There is an ifdef in the PALcode in MILO that enables a
 405    "kernel debugging entry point" as an unprivileged call_pal.
 406
 407    We don't want to have anything to do with it, but unfortunately
 408    several versions of MILO included in distributions have it enabled,
 409    and if we don't put something on the entry point we'll oops.  */
 410
 411 asmlinkage void
 412 do_entDbg(struct pt_regs *regs)
 413 {
 414         siginfo_t info;
 415
 416         die_if_kernel("Instruction fault", regs, 0, NULL);
 417
 418         info.si_signo = SIGILL;
 419         info.si_errno = 0;
 420         info.si_code = ILL_ILLOPC;
 421         info.si_addr = (void __user *) regs->pc;
 422         force_sig_info(SIGILL, &info, current);
 423 }
 424
 425
 426 /*
 427  * entUna has a different register layout to be reasonably simple. It
 428  * needs access to all the integer registers (the kernel doesn't use
 429  * fp-regs), and it needs to have them in order for simpler access.
 430  *
 431  * Due to the non-standard register layout (and because we don't want
 432  * to handle floating-point regs), user-mode unaligned accesses are
 433  * handled separately by do_entUnaUser below.
 434  *
 435  * Oh, btw, we don't handle the "gp" register correctly, but if we fault
 436  * on a gp-register unaligned load/store, something is _very_ wrong
 437  * in the kernel anyway..
 438  */
 439 struct allregs {
 440         unsigned long regs[32];
 441         unsigned long ps, pc, gp, a0, a1, a2;
 442 };
 443
 444 struct unaligned_stat {
 445         unsigned long count, va, pc;
 446 } unaligned[2];
 447
 448
 449 /* Macro for exception fixup code to access integer registers.  */
 450 #define una_reg(r)  (_regs[(r) >= 16 && (r) <= 18 ? (r)+19 : (r)])
 451
 452
 453 asmlinkage void
 454 do_entUna(void * va, unsigned long opcode, unsigned long reg,
 455           struct allregs *regs)
 456 {
 457         long error, tmp1, tmp2, tmp3, tmp4;
 458         unsigned long pc = regs->pc - 4;
 459         unsigned long *_regs = regs->regs;
 460         const struct exception_table_entry *fixup;
 461
 462         unaligned[0].count++;
 463         unaligned[0].va = (unsigned long) va;
 464         unaligned[0].pc = pc;
 465
 466         /* We don't want to use the generic get/put unaligned macros as
 467            we want to trap exceptions.  Only if we actually get an
 468            exception will we decide whether we should have caught it.  */
 469
 470         switch (opcode) {
 471         case 0x0c: /* ldwu */
 472                 __asm__ __volatile__(
 473                 "1:     ldq_u %1,0(%3)\n"
 474                 "2:     ldq_u %2,1(%3)\n"
 475                 "       extwl %1,%3,%1\n"
 476                 "       extwh %2,%3,%2\n"
 477                 "3:\n"
 478                 ".section __ex_table,\"a\"\n"
 479                 "       .long 1b - .\n"
 480                 "       lda %1,3b-1b(%0)\n"
 481                 "       .long 2b - .\n"
 482                 "       lda %2,3b-2b(%0)\n"
 483                 ".previous"
 484                         : "=r"(error), "=&r"(tmp1), "=&r"(tmp2)
 485                         : "r"(va), "0"(0));
 486                 if (error)
 487                         goto got_exception;
 488                 una_reg(reg) = tmp1|tmp2;
 489                 return;
 490
 491         case 0x28: /* ldl */
 492                 __asm__ __volatile__(
 493                 "1:     ldq_u %1,0(%3)\n"
 494                 "2:     ldq_u %2,3(%3)\n"
 495                 "       extll %1,%3,%1\n"
 496                 "       extlh %2,%3,%2\n"
 497                 "3:\n"
 498                 ".section __ex_table,\"a\"\n"
 499                 "       .long 1b - .\n"
 500                 "       lda %1,3b-1b(%0)\n"
 501                 "       .long 2b - .\n"
 502                 "       lda %2,3b-2b(%0)\n"
 503                 ".previous"
 504                         : "=r"(error), "=&r"(tmp1), "=&r"(tmp2)
 505                         : "r"(va), "0"(0));
 506                 if (error)
 507                         goto got_exception;
 508                 una_reg(reg) = (int)(tmp1|tmp2);
 509                 return;
 510
 511         case 0x29: /* ldq */
 512                 __asm__ __volatile__(
 513                 "1:     ldq_u %1,0(%3)\n"
 514                 "2:     ldq_u %2,7(%3)\n"
 515                 "       extql %1,%3,%1\n"
 516                 "       extqh %2,%3,%2\n"
 517                 "3:\n"
 518                 ".section __ex_table,\"a\"\n"
 519                 "       .long 1b - .\n"
 520                 "       lda %1,3b-1b(%0)\n"
 521                 "       .long 2b - .\n"
 522                 "       lda %2,3b-2b(%0)\n"
 523                 ".previous"
 524                         : "=r"(error), "=&r"(tmp1), "=&r"(tmp2)
 525                         : "r"(va), "0"(0));
 526                 if (error)
 527                         goto got_exception;
 528                 una_reg(reg) = tmp1|tmp2;
 529                 return;
 530
 531         /* Note that the store sequences do not indicate that they change
 532            memory because it _should_ be affecting nothing in this context.
 533            (Otherwise we have other, much larger, problems.)  */
 534         case 0x0d: /* stw */
 535                 __asm__ __volatile__(
 536                 "1:     ldq_u %2,1(%5)\n"
 537                 "2:     ldq_u %1,0(%5)\n"
 538                 "       inswh %6,%5,%4\n"
 539                 "       inswl %6,%5,%3\n"
 540                 "       mskwh %2,%5,%2\n"
 541                 "       mskwl %1,%5,%1\n"
 542                 "       or %2,%4,%2\n"
 543                 "       or %1,%3,%1\n"
 544                 "3:     stq_u %2,1(%5)\n"
 545                 "4:     stq_u %1,0(%5)\n"
 546                 "5:\n"
 547                 ".section __ex_table,\"a\"\n"
 548                 "       .long 1b - .\n"
 549                 "       lda %2,5b-1b(%0)\n"
 550                 "       .long 2b - .\n"
 551                 "       lda %1,5b-2b(%0)\n"
 552                 "       .long 3b - .\n"
 553                 "       lda $31,5b-3b(%0)\n"
 554                 "       .long 4b - .\n"
 555                 "       lda $31,5b-4b(%0)\n"
 556                 ".previous"
 557                         : "=r"(error), "=&r"(tmp1), "=&r"(tmp2),
 558                           "=&r"(tmp3), "=&r"(tmp4)
 559                         : "r"(va), "r"(una_reg(reg)), "0"(0));
 560                 if (error)
 561                         goto got_exception;
 562                 return;
 563
 564         case 0x2c: /* stl */
 565                 __asm__ __volatile__(
 566                 "1:     ldq_u %2,3(%5)\n"
 567                 "2:     ldq_u %1,0(%5)\n"
 568                 "       inslh %6,%5,%4\n"
 569                 "       insll %6,%5,%3\n"
 570                 "       msklh %2,%5,%2\n"
 571                 "       mskll %1,%5,%1\n"
 572                 "       or %2,%4,%2\n"
 573                 "       or %1,%3,%1\n"
 574                 "3:     stq_u %2,3(%5)\n"
 575                 "4:     stq_u %1,0(%5)\n"
 576                 "5:\n"
 577                 ".section __ex_table,\"a\"\n"
 578                 "       .long 1b - .\n"
 579                 "       lda %2,5b-1b(%0)\n"
 580                 "       .long 2b - .\n"
 581                 "       lda %1,5b-2b(%0)\n"
 582                 "       .long 3b - .\n"
 583                 "       lda $31,5b-3b(%0)\n"
 584                 "       .long 4b - .\n"
 585                 "       lda $31,5b-4b(%0)\n"
 586                 ".previous"
 587                         : "=r"(error), "=&r"(tmp1), "=&r"(tmp2),
 588                           "=&r"(tmp3), "=&r"(tmp4)
 589                         : "r"(va), "r"(una_reg(reg)), "0"(0));
 590                 if (error)
 591                         goto got_exception;
 592                 return;
 593
 594         case 0x2d: /* stq */
 595                 __asm__ __volatile__(
 596                 "1:     ldq_u %2,7(%5)\n"
 597                 "2:     ldq_u %1,0(%5)\n"
 598                 "       insqh %6,%5,%4\n"
 599                 "       insql %6,%5,%3\n"
 600                 "       mskqh %2,%5,%2\n"
 601                 "       mskql %1,%5,%1\n"
 602                 "       or %2,%4,%2\n"
 603                 "       or %1,%3,%1\n"
 604                 "3:     stq_u %2,7(%5)\n"
 605                 "4:     stq_u %1,0(%5)\n"
 606                 "5:\n"
 607                 ".section __ex_table,\"a\"\n\t"
 608                 "       .long 1b - .\n"
 609                 "       lda %2,5b-1b(%0)\n"
 610                 "       .long 2b - .\n"
 611                 "       lda %1,5b-2b(%0)\n"
 612                 "       .long 3b - .\n"
 613                 "       lda $31,5b-3b(%0)\n"
 614                 "       .long 4b - .\n"
 615                 "       lda $31,5b-4b(%0)\n"
 616                 ".previous"
 617                         : "=r"(error), "=&r"(tmp1), "=&r"(tmp2),
 618                           "=&r"(tmp3), "=&r"(tmp4)
 619                         : "r"(va), "r"(una_reg(reg)), "0"(0));
 620                 if (error)
 621                         goto got_exception;
 622                 return;
 623         }
 624
 625         lock_kernel();
 626         printk("Bad unaligned kernel access at %016lx: %p %lx %ld\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         lock_kernel();
 649
 650         printk("%s(%d): unhandled unaligned exception\n",
 651                current->comm, task_pid_nr(current));
 652
 653         printk("pc = [<%016lx>]  ra = [<%016lx>]  ps = %04lx\n",
 654                pc, una_reg(26), regs->ps);
 655         printk("r0 = %016lx  r1 = %016lx  r2 = %016lx\n",
 656                una_reg(0), una_reg(1), una_reg(2));
 657         printk("r3 = %016lx  r4 = %016lx  r5 = %016lx\n",
 658                una_reg(3), una_reg(4), una_reg(5));
 659         printk("r6 = %016lx  r7 = %016lx  r8 = %016lx\n",
 660                una_reg(6), una_reg(7), una_reg(8));
 661         printk("r9 = %016lx  r10= %016lx  r11= %016lx\n",
 662                una_reg(9), una_reg(10), una_reg(11));
 663         printk("r12= %016lx  r13= %016lx  r14= %016lx\n",
 664                una_reg(12), una_reg(13), una_reg(14));
 665         printk("r15= %016lx\n", una_reg(15));
 666         printk("r16= %016lx  r17= %016lx  r18= %016lx\n",
 667                una_reg(16), una_reg(17), una_reg(18));
 668         printk("r19= %016lx  r20= %016lx  r21= %016lx\n",
 669                una_reg(19), una_reg(20), una_reg(21));
 670         printk("r22= %016lx  r23= %016lx  r24= %016lx\n",
 671                una_reg(22), una_reg(23), una_reg(24));
 672         printk("r25= %016lx  r27= %016lx  r28= %016lx\n",
 673                una_reg(25), una_reg(27), una_reg(28));
 674         printk("gp = %016lx  sp = %p\n", regs->gp, regs+1);
 675
 676         dik_show_code((unsigned int *)pc);
 677         dik_show_trace((unsigned long *)(regs+1));
 678
 679         if (test_and_set_thread_flag (TIF_DIE_IF_KERNEL)) {
 680                 printk("die_if_kernel recursion detected.\n");
 681                 local_irq_enable();
 682                 while (1);
 683         }
 684         do_exit(SIGSEGV);
 685 }
 686
 687 /*
 688  * Convert an s-floating point value in memory format to the
 689  * corresponding value in register format.  The exponent
 690  * needs to be remapped to preserve non-finite values
 691  * (infinities, not-a-numbers, denormals).
 692  */
 693 static inline unsigned long
 694 s_mem_to_reg (unsigned long s_mem)
 695 {
 696         unsigned long frac    = (s_mem >>  0) & 0x7fffff;
 697         unsigned long sign    = (s_mem >> 31) & 0x1;
 698         unsigned long exp_msb = (s_mem >> 30) & 0x1;
 699         unsigned long exp_low = (s_mem >> 23) & 0x7f;
 700         unsigned long exp;
 701
 702         exp = (exp_msb << 10) | exp_low;        /* common case */
 703         if (exp_msb) {
 704                 if (exp_low == 0x7f) {
 705                         exp = 0x7ff;
 706                 }
 707         } else {
 708                 if (exp_low == 0x00) {
 709                         exp = 0x000;
 710                 } else {
 711                         exp |= (0x7 << 7);
 712                 }
 713         }
 714         return (sign << 63) | (exp << 52) | (frac << 29);
 715 }
 716
 717 /*
 718  * Convert an s-floating point value in register format to the
 719  * corresponding value in memory format.
 720  */
 721 static inline unsigned long
 722 s_reg_to_mem (unsigned long s_reg)
 723 {
 724         return ((s_reg >> 62) << 30) | ((s_reg << 5) >> 34);
 725 }
 726
 727 /*
 728  * Handle user-level unaligned fault.  Handling user-level unaligned
 729  * faults is *extremely* slow and produces nasty messages.  A user
 730  * program *should* fix unaligned faults ASAP.
 731  *
 732  * Notice that we have (almost) the regular kernel stack layout here,
 733  * so finding the appropriate registers is a little more difficult
 734  * than in the kernel case.
 735  *
 736  * Finally, we handle regular integer load/stores only.  In
 737  * particular, load-linked/store-conditionally and floating point
 738  * load/stores are not supported.  The former make no sense with
 739  * unaligned faults (they are guaranteed to fail) and I don't think
 740  * the latter will occur in any decent program.
 741  *
 742  * Sigh. We *do* have to handle some FP operations, because GCC will
 743  * uses them as temporary storage for integer memory to memory copies.
 744  * However, we need to deal with stt/ldt and sts/lds only.
 745  */
 746
 747 #define OP_INT_MASK     ( 1L << 0x28 | 1L << 0x2c   /* ldl stl */       \
 748                         | 1L << 0x29 | 1L << 0x2d   /* ldq stq */       \
 749                         | 1L << 0x0c | 1L << 0x0d   /* ldwu stw */      \
 750                         | 1L << 0x0a | 1L << 0x0e ) /* ldbu stb */
 751
 752 #define OP_WRITE_MASK   ( 1L << 0x26 | 1L << 0x27   /* sts stt */       \
 753                         | 1L << 0x2c | 1L << 0x2d   /* stl stq */       \
 754                         | 1L << 0x0d | 1L << 0x0e ) /* stw stb */
 755
 756 #define R(x)    ((size_t) &((struct pt_regs *)0)->x)
 757
 758 static int unauser_reg_offsets[32] = {
 759         R(r0), R(r1), R(r2), R(r3), R(r4), R(r5), R(r6), R(r7), R(r8),
 760         /* r9 ... r15 are stored in front of regs.  */
 761         -56, -48, -40, -32, -24, -16, -8,
 762         R(r16), R(r17), R(r18),
 763         R(r19), R(r20), R(r21), R(r22), R(r23), R(r24), R(r25), R(r26),
 764         R(r27), R(r28), R(gp),
 765         0, 0
 766 };
 767
 768 #undef R
 769
 770 asmlinkage void
 771 do_entUnaUser(void __user * va, unsigned long opcode,
 772               unsigned long reg, struct pt_regs *regs)
 773 {
 774         static int cnt = 0;
 775         static unsigned long last_time;
 776
 777         unsigned long tmp1, tmp2, tmp3, tmp4;
 778         unsigned long fake_reg, *reg_addr = &fake_reg;
 779         siginfo_t info;
 780         long error;
 781
 782         /* Check the UAC bits to decide what the user wants us to do
 783            with the unaliged access.  */
 784
 785         if (!test_thread_flag (TIF_UAC_NOPRINT)) {
 786                 if (cnt >= 5 && time_after(jiffies, last_time + 5 * HZ)) {
 787                         cnt = 0;
 788                 }
 789                 if (++cnt < 5) {
 790                         printk("%s(%d): unaligned trap at %016lx: %p %lx %ld\n",
 791                                current->comm, task_pid_nr(current),
 792                                regs->pc - 4, va, opcode, reg);
 793                 }
 794                 last_time = jiffies;
 795         }
 796         if (test_thread_flag (TIF_UAC_SIGBUS))
 797                 goto give_sigbus;
 798         /* Not sure why you'd want to use this, but... */
 799         if (test_thread_flag (TIF_UAC_NOFIX))
 800                 return;
 801
 802         /* Don't bother reading ds in the access check since we already
 803            know that this came from the user.  Also rely on the fact that
 804            the page at TASK_SIZE is unmapped and so can't be touched anyway. */
 805         if (!__access_ok((unsigned long)va, 0, USER_DS))
 806                 goto give_sigsegv;
 807
 808         ++unaligned[1].count;
 809         unaligned[1].va = (unsigned long)va;
 810         unaligned[1].pc = regs->pc - 4;
 811
 812         if ((1L << opcode) & OP_INT_MASK) {
 813                 /* it's an integer load/store */
 814                 if (reg < 30) {
 815                         reg_addr = (unsigned long *)
 816                           ((char *)regs + unauser_reg_offsets[reg]);
 817                 } else if (reg == 30) {
 818                         /* usp in PAL regs */
 819                         fake_reg = rdusp();
 820                 } else {
 821                         /* zero "register" */
 822                         fake_reg = 0;
 823                 }
 824         }
 825
 826         /* We don't want to use the generic get/put unaligned macros as
 827            we want to trap exceptions.  Only if we actually get an
 828            exception will we decide whether we should have caught it.  */
 829
 830         switch (opcode) {
 831         case 0x0c: /* ldwu */
 832                 __asm__ __volatile__(
 833                 "1:     ldq_u %1,0(%3)\n"
 834                 "2:     ldq_u %2,1(%3)\n"
 835                 "       extwl %1,%3,%1\n"
 836                 "       extwh %2,%3,%2\n"
 837                 "3:\n"
 838                 ".section __ex_table,\"a\"\n"
 839                 "       .long 1b - .\n"
 840                 "       lda %1,3b-1b(%0)\n"
 841                 "       .long 2b - .\n"
 842                 "       lda %2,3b-2b(%0)\n"
 843                 ".previous"
 844                         : "=r"(error), "=&r"(tmp1), "=&r"(tmp2)
 845                         : "r"(va), "0"(0));
 846                 if (error)
 847                         goto give_sigsegv;
 848                 *reg_addr = tmp1|tmp2;
 849                 break;
 850
 851         case 0x22: /* lds */
 852                 __asm__ __volatile__(
 853                 "1:     ldq_u %1,0(%3)\n"
 854                 "2:     ldq_u %2,3(%3)\n"
 855                 "       extll %1,%3,%1\n"
 856                 "       extlh %2,%3,%2\n"
 857                 "3:\n"
 858                 ".section __ex_table,\"a\"\n"
 859                 "       .long 1b - .\n"
 860                 "       lda %1,3b-1b(%0)\n"
 861                 "       .long 2b - .\n"
 862                 "       lda %2,3b-2b(%0)\n"
 863                 ".previous"
 864                         : "=r"(error), "=&r"(tmp1), "=&r"(tmp2)
 865                         : "r"(va), "0"(0));
 866                 if (error)
 867                         goto give_sigsegv;
 868                 alpha_write_fp_reg(reg, s_mem_to_reg((int)(tmp1|tmp2)));
 869                 return;
 870
 871         case 0x23: /* ldt */
 872                 __asm__ __volatile__(
 873                 "1:     ldq_u %1,0(%3)\n"
 874                 "2:     ldq_u %2,7(%3)\n"
 875                 "       extql %1,%3,%1\n"
 876                 "       extqh %2,%3,%2\n"
 877                 "3:\n"
 878                 ".section __ex_table,\"a\"\n"
 879                 "       .long 1b - .\n"
 880                 "       lda %1,3b-1b(%0)\n"
 881                 "       .long 2b - .\n"
 882                 "       lda %2,3b-2b(%0)\n"
 883                 ".previous"
 884                         : "=r"(error), "=&r"(tmp1), "=&r"(tmp2)
 885                         : "r"(va), "0"(0));
 886                 if (error)
 887                         goto give_sigsegv;
 888                 alpha_write_fp_reg(reg, tmp1|tmp2);
 889                 return;
 890
 891         case 0x28: /* ldl */
 892                 __asm__ __volatile__(
 893                 "1:     ldq_u %1,0(%3)\n"
 894                 "2:     ldq_u %2,3(%3)\n"
 895                 "       extll %1,%3,%1\n"
 896                 "       extlh %2,%3,%2\n"
 897                 "3:\n"
 898                 ".section __ex_table,\"a\"\n"
 899                 "       .long 1b - .\n"
 900                 "       lda %1,3b-1b(%0)\n"
 901                 "       .long 2b - .\n"
 902                 "       lda %2,3b-2b(%0)\n"
 903                 ".previous"
 904                         : "=r"(error), "=&r"(tmp1), "=&r"(tmp2)
 905                         : "r"(va), "0"(0));
 906                 if (error)
 907                         goto give_sigsegv;
 908                 *reg_addr = (int)(tmp1|tmp2);
 909                 break;
 910
 911         case 0x29: /* ldq */
 912                 __asm__ __volatile__(
 913                 "1:     ldq_u %1,0(%3)\n"
 914                 "2:     ldq_u %2,7(%3)\n"
 915                 "       extql %1,%3,%1\n"
 916                 "       extqh %2,%3,%2\n"
 917                 "3:\n"
 918                 ".section __ex_table,\"a\"\n"
 919                 "       .long 1b - .\n"
 920                 "       lda %1,3b-1b(%0)\n"
 921                 "       .long 2b - .\n"
 922                 "       lda %2,3b-2b(%0)\n"
 923                 ".previous"
 924                         : "=r"(error), "=&r"(tmp1), "=&r"(tmp2)
 925                         : "r"(va), "0"(0));
 926                 if (error)
 927                         goto give_sigsegv;
 928                 *reg_addr = tmp1|tmp2;
 929                 break;
 930
 931         /* Note that the store sequences do not indicate that they change
 932            memory because it _should_ be affecting nothing in this context.
 933            (Otherwise we have other, much larger, problems.)  */
 934         case 0x0d: /* stw */
 935                 __asm__ __volatile__(
 936                 "1:     ldq_u %2,1(%5)\n"
 937                 "2:     ldq_u %1,0(%5)\n"
 938                 "       inswh %6,%5,%4\n"
 939                 "       inswl %6,%5,%3\n"
 940                 "       mskwh %2,%5,%2\n"
 941                 "       mskwl %1,%5,%1\n"
 942                 "       or %2,%4,%2\n"
 943                 "       or %1,%3,%1\n"
 944                 "3:     stq_u %2,1(%5)\n"
 945                 "4:     stq_u %1,0(%5)\n"
 946                 "5:\n"
 947                 ".section __ex_table,\"a\"\n"
 948                 "       .long 1b - .\n"
 949                 "       lda %2,5b-1b(%0)\n"
 950                 "       .long 2b - .\n"
 951                 "       lda %1,5b-2b(%0)\n"
 952                 "       .long 3b - .\n"
 953                 "       lda $31,5b-3b(%0)\n"
 954                 "       .long 4b - .\n"
 955                 "       lda $31,5b-4b(%0)\n"
 956                 ".previous"
 957                         : "=r"(error), "=&r"(tmp1), "=&r"(tmp2),
 958                           "=&r"(tmp3), "=&r"(tmp4)
 959                         : "r"(va), "r"(*reg_addr), "0"(0));
 960                 if (error)
 961                         goto give_sigsegv;
 962                 return;
 963
 964         case 0x26: /* sts */
 965                 fake_reg = s_reg_to_mem(alpha_read_fp_reg(reg));
 966                 /* FALLTHRU */
 967
 968         case 0x2c: /* stl */
 969                 __asm__ __volatile__(
 970                 "1:     ldq_u %2,3(%5)\n"
 971                 "2:     ldq_u %1,0(%5)\n"
 972                 "       inslh %6,%5,%4\n"
 973                 "       insll %6,%5,%3\n"
 974                 "       msklh %2,%5,%2\n"
 975                 "       mskll %1,%5,%1\n"
 976                 "       or %2,%4,%2\n"
 977                 "       or %1,%3,%1\n"
 978                 "3:     stq_u %2,3(%5)\n"
 979                 "4:     stq_u %1,0(%5)\n"
 980                 "5:\n"
 981                 ".section __ex_table,\"a\"\n"
 982                 "       .long 1b - .\n"
 983                 "       lda %2,5b-1b(%0)\n"
 984                 "       .long 2b - .\n"
 985                 "       lda %1,5b-2b(%0)\n"
 986                 "       .long 3b - .\n"
 987                 "       lda $31,5b-3b(%0)\n"
 988                 "       .long 4b - .\n"
 989                 "       lda $31,5b-4b(%0)\n"
 990                 ".previous"
 991                         : "=r"(error), "=&r"(tmp1), "=&r"(tmp2),
 992                           "=&r"(tmp3), "=&r"(tmp4)
 993                         : "r"(va), "r"(*reg_addr), "0"(0));
 994                 if (error)
 995                         goto give_sigsegv;
 996                 return;
 997
 998         case 0x27: /* stt */
 999                 fake_reg = alpha_read_fp_reg(reg);
1000                 /* FALLTHRU */
1001
1002         case 0x2d: /* stq */
1003                 __asm__ __volatile__(
1004                 "1:     ldq_u %2,7(%5)\n"
1005                 "2:     ldq_u %1,0(%5)\n"
1006                 "       insqh %6,%5,%4\n"
1007                 "       insql %6,%5,%3\n"
1008                 "       mskqh %2,%5,%2\n"
1009                 "       mskql %1,%5,%1\n"
1010                 "       or %2,%4,%2\n"
1011                 "       or %1,%3,%1\n"
1012                 "3:     stq_u %2,7(%5)\n"
1013                 "4:     stq_u %1,0(%5)\n"
1014                 "5:\n"
1015                 ".section __ex_table,\"a\"\n\t"
1016                 "       .long 1b - .\n"
1017                 "       lda %2,5b-1b(%0)\n"
1018                 "       .long 2b - .\n"
1019                 "       lda %1,5b-2b(%0)\n"
1020                 "       .long 3b - .\n"
1021                 "       lda $31,5b-3b(%0)\n"
1022                 "       .long 4b - .\n"
1023                 "       lda $31,5b-4b(%0)\n"
1024                 ".previous"
1025                         : "=r"(error), "=&r"(tmp1), "=&r"(tmp2),
1026                           "=&r"(tmp3), "=&r"(tmp4)
1027                         : "r"(va), "r"(*reg_addr), "0"(0));
1028                 if (error)
1029                         goto give_sigsegv;
1030                 return;
1031
1032         default:
1033                 /* What instruction were you trying to use, exactly?  */
1034                 goto give_sigbus;
1035         }
1036
1037         /* Only integer loads should get here; everyone else returns early. */
1038         if (reg == 30)
1039                 wrusp(fake_reg);
1040         return;
1041
1042 give_sigsegv:
1043         regs->pc -= 4;  /* make pc point to faulting insn */
1044         info.si_signo = SIGSEGV;
1045         info.si_errno = 0;
1046
1047         /* We need to replicate some of the logic in mm/fault.c,
1048            since we don't have access to the fault code in the
1049            exception handling return path.  */
1050         if (!__access_ok((unsigned long)va, 0, USER_DS))
1051                 info.si_code = SEGV_ACCERR;
1052         else {
1053                 struct mm_struct *mm = current->mm;
1054                 down_read(&mm->mmap_sem);
1055                 if (find_vma(mm, (unsigned long)va))
1056                         info.si_code = SEGV_ACCERR;
1057                 else
1058                         info.si_code = SEGV_MAPERR;
1059                 up_read(&mm->mmap_sem);
1060         }
1061         info.si_addr = va;
1062         send_sig_info(SIGSEGV, &info, current);
1063         return;
1064
1065 give_sigbus:
1066         regs->pc -= 4;
1067         info.si_signo = SIGBUS;
1068         info.si_errno = 0;
1069         info.si_code = BUS_ADRALN;
1070         info.si_addr = va;
1071         send_sig_info(SIGBUS, &info, current);
1072         return;
1073 }
1074
1075 void __init
1076 trap_init(void)
1077 {
1078         /* Tell PAL-code what global pointer we want in the kernel.  */
1079         register unsigned long gptr __asm__("$29");
1080         wrkgp(gptr);
1081
1082         /* Hack for Multia (UDB) and JENSEN: some of their SRMs have
1083            a bug in the handling of the opDEC fault.  Fix it up if so.  */
1084         if (implver() == IMPLVER_EV4)
1085                 opDEC_check();
1086
1087         wrent(entArith, 1);
1088         wrent(entMM, 2);
1089         wrent(entIF, 3);
1090         wrent(entUna, 4);
1091         wrent(entSys, 5);
1092         wrent(entDbg, 6);
1093 }