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   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->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         const struct exception_table_entry *fixup;
 460
 461         unaligned[0].count++;
 462         unaligned[0].va = (unsigned long) va;
 463         unaligned[0].pc = pc;
 464
 465         /* We don't want to use the generic get/put unaligned macros as
 466            we want to trap exceptions.  Only if we actually get an
 467            exception will we decide whether we should have caught it.  */
 468
 469         switch (opcode) {
 470         case 0x0c: /* ldwu */
 471                 __asm__ __volatile__(
 472                 "1:     ldq_u %1,0(%3)\n"
 473                 "2:     ldq_u %2,1(%3)\n"
 474                 "       extwl %1,%3,%1\n"
 475                 "       extwh %2,%3,%2\n"
 476                 "3:\n"
 477                 ".section __ex_table,\"a\"\n"
 478                 "       .long 1b - .\n"
 479                 "       lda %1,3b-1b(%0)\n"
 480                 "       .long 2b - .\n"
 481                 "       lda %2,3b-2b(%0)\n"
 482                 ".previous"
 483                         : "=r"(error), "=&r"(tmp1), "=&r"(tmp2)
 484                         : "r"(va), "0"(0));
 485                 if (error)
 486                         goto got_exception;
 487                 una_reg(reg) = tmp1|tmp2;
 488                 return;
 489
 490         case 0x28: /* ldl */
 491                 __asm__ __volatile__(
 492                 "1:     ldq_u %1,0(%3)\n"
 493                 "2:     ldq_u %2,3(%3)\n"
 494                 "       extll %1,%3,%1\n"
 495                 "       extlh %2,%3,%2\n"
 496                 "3:\n"
 497                 ".section __ex_table,\"a\"\n"
 498                 "       .long 1b - .\n"
 499                 "       lda %1,3b-1b(%0)\n"
 500                 "       .long 2b - .\n"
 501                 "       lda %2,3b-2b(%0)\n"
 502                 ".previous"
 503                         : "=r"(error), "=&r"(tmp1), "=&r"(tmp2)
 504                         : "r"(va), "0"(0));
 505                 if (error)
 506                         goto got_exception;
 507                 una_reg(reg) = (int)(tmp1|tmp2);
 508                 return;
 509
 510         case 0x29: /* ldq */
 511                 __asm__ __volatile__(
 512                 "1:     ldq_u %1,0(%3)\n"
 513                 "2:     ldq_u %2,7(%3)\n"
 514                 "       extql %1,%3,%1\n"
 515                 "       extqh %2,%3,%2\n"
 516                 "3:\n"
 517                 ".section __ex_table,\"a\"\n"
 518                 "       .long 1b - .\n"
 519                 "       lda %1,3b-1b(%0)\n"
 520                 "       .long 2b - .\n"
 521                 "       lda %2,3b-2b(%0)\n"
 522                 ".previous"
 523                         : "=r"(error), "=&r"(tmp1), "=&r"(tmp2)
 524                         : "r"(va), "0"(0));
 525                 if (error)
 526                         goto got_exception;
 527                 una_reg(reg) = tmp1|tmp2;
 528                 return;
 529
 530         /* Note that the store sequences do not indicate that they change
 531            memory because it _should_ be affecting nothing in this context.
 532            (Otherwise we have other, much larger, problems.)  */
 533         case 0x0d: /* stw */
 534                 __asm__ __volatile__(
 535                 "1:     ldq_u %2,1(%5)\n"
 536                 "2:     ldq_u %1,0(%5)\n"
 537                 "       inswh %6,%5,%4\n"
 538                 "       inswl %6,%5,%3\n"
 539                 "       mskwh %2,%5,%2\n"
 540                 "       mskwl %1,%5,%1\n"
 541                 "       or %2,%4,%2\n"
 542                 "       or %1,%3,%1\n"
 543                 "3:     stq_u %2,1(%5)\n"
 544                 "4:     stq_u %1,0(%5)\n"
 545                 "5:\n"
 546                 ".section __ex_table,\"a\"\n"
 547                 "       .long 1b - .\n"
 548                 "       lda %2,5b-1b(%0)\n"
 549                 "       .long 2b - .\n"
 550                 "       lda %1,5b-2b(%0)\n"
 551                 "       .long 3b - .\n"
 552                 "       lda $31,5b-3b(%0)\n"
 553                 "       .long 4b - .\n"
 554                 "       lda $31,5b-4b(%0)\n"
 555                 ".previous"
 556                         : "=r"(error), "=&r"(tmp1), "=&r"(tmp2),
 557                           "=&r"(tmp3), "=&r"(tmp4)
 558                         : "r"(va), "r"(una_reg(reg)), "0"(0));
 559                 if (error)
 560                         goto got_exception;
 561                 return;
 562
 563         case 0x2c: /* stl */
 564                 __asm__ __volatile__(
 565                 "1:     ldq_u %2,3(%5)\n"
 566                 "2:     ldq_u %1,0(%5)\n"
 567                 "       inslh %6,%5,%4\n"
 568                 "       insll %6,%5,%3\n"
 569                 "       msklh %2,%5,%2\n"
 570                 "       mskll %1,%5,%1\n"
 571                 "       or %2,%4,%2\n"
 572                 "       or %1,%3,%1\n"
 573                 "3:     stq_u %2,3(%5)\n"
 574                 "4:     stq_u %1,0(%5)\n"
 575                 "5:\n"
 576                 ".section __ex_table,\"a\"\n"
 577                 "       .long 1b - .\n"
 578                 "       lda %2,5b-1b(%0)\n"
 579                 "       .long 2b - .\n"
 580                 "       lda %1,5b-2b(%0)\n"
 581                 "       .long 3b - .\n"
 582                 "       lda $31,5b-3b(%0)\n"
 583                 "       .long 4b - .\n"
 584                 "       lda $31,5b-4b(%0)\n"
 585                 ".previous"
 586                         : "=r"(error), "=&r"(tmp1), "=&r"(tmp2),
 587                           "=&r"(tmp3), "=&r"(tmp4)
 588                         : "r"(va), "r"(una_reg(reg)), "0"(0));
 589                 if (error)
 590                         goto got_exception;
 591                 return;
 592
 593         case 0x2d: /* stq */
 594                 __asm__ __volatile__(
 595                 "1:     ldq_u %2,7(%5)\n"
 596                 "2:     ldq_u %1,0(%5)\n"
 597                 "       insqh %6,%5,%4\n"
 598                 "       insql %6,%5,%3\n"
 599                 "       mskqh %2,%5,%2\n"
 600                 "       mskql %1,%5,%1\n"
 601                 "       or %2,%4,%2\n"
 602                 "       or %1,%3,%1\n"
 603                 "3:     stq_u %2,7(%5)\n"
 604                 "4:     stq_u %1,0(%5)\n"
 605                 "5:\n"
 606                 ".section __ex_table,\"a\"\n\t"
 607                 "       .long 1b - .\n"
 608                 "       lda %2,5b-1b(%0)\n"
 609                 "       .long 2b - .\n"
 610                 "       lda %1,5b-2b(%0)\n"
 611                 "       .long 3b - .\n"
 612                 "       lda $31,5b-3b(%0)\n"
 613                 "       .long 4b - .\n"
 614                 "       lda $31,5b-4b(%0)\n"
 615                 ".previous"
 616                         : "=r"(error), "=&r"(tmp1), "=&r"(tmp2),
 617                           "=&r"(tmp3), "=&r"(tmp4)
 618                         : "r"(va), "r"(una_reg(reg)), "0"(0));
 619                 if (error)
 620                         goto got_exception;
 621                 return;
 622         }
 623
 624         lock_kernel();
 625         printk("Bad unaligned kernel access at %016lx: %p %lx %ld\n",
 626                 pc, va, opcode, reg);
 627         do_exit(SIGSEGV);
 628
 629 got_exception:
 630         /* Ok, we caught the exception, but we don't want it.  Is there
 631            someone to pass it along to?  */
 632         if ((fixup = search_exception_tables(pc)) != 0) {
 633                 unsigned long newpc;
 634                 newpc = fixup_exception(una_reg, fixup, pc);
 635
 636                 printk("Forwarding unaligned exception at %lx (%lx)\n",
 637                        pc, newpc);
 638
 639                 regs->pc = newpc;
 640                 return;
 641         }
 642
 643         /*
 644          * Yikes!  No one to forward the exception to.
 645          * Since the registers are in a weird format, dump them ourselves.
 646          */
 647         lock_kernel();
 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 int cnt = 0;
 774         static unsigned long last_time;
 775
 776         unsigned long tmp1, tmp2, tmp3, tmp4;
 777         unsigned long fake_reg, *reg_addr = &fake_reg;
 778         siginfo_t info;
 779         long error;
 780
 781         /* Check the UAC bits to decide what the user wants us to do
 782            with the unaliged access.  */
 783
 784         if (!test_thread_flag (TIF_UAC_NOPRINT)) {
 785                 if (cnt >= 5 && time_after(jiffies, last_time + 5 * HZ)) {
 786                         cnt = 0;
 787                 }
 788                 if (++cnt < 5) {
 789                         printk("%s(%d): unaligned trap at %016lx: %p %lx %ld\n",
 790                                current->comm, task_pid_nr(current),
 791                                regs->pc - 4, va, opcode, reg);
 792                 }
 793                 last_time = jiffies;
 794         }
 795         if (test_thread_flag (TIF_UAC_SIGBUS))
 796                 goto give_sigbus;
 797         /* Not sure why you'd want to use this, but... */
 798         if (test_thread_flag (TIF_UAC_NOFIX))
 799                 return;
 800
 801         /* Don't bother reading ds in the access check since we already
 802            know that this came from the user.  Also rely on the fact that
 803            the page at TASK_SIZE is unmapped and so can't be touched anyway. */
 804         if (!__access_ok((unsigned long)va, 0, USER_DS))
 805                 goto give_sigsegv;
 806
 807         ++unaligned[1].count;
 808         unaligned[1].va = (unsigned long)va;
 809         unaligned[1].pc = regs->pc - 4;
 810
 811         if ((1L << opcode) & OP_INT_MASK) {
 812                 /* it's an integer load/store */
 813                 if (reg < 30) {
 814                         reg_addr = (unsigned long *)
 815                           ((char *)regs + unauser_reg_offsets[reg]);
 816                 } else if (reg == 30) {
 817                         /* usp in PAL regs */
 818                         fake_reg = rdusp();
 819                 } else {
 820                         /* zero "register" */
 821                         fake_reg = 0;
 822                 }
 823         }
 824
 825         /* We don't want to use the generic get/put unaligned macros as
 826            we want to trap exceptions.  Only if we actually get an
 827            exception will we decide whether we should have caught it.  */
 828
 829         switch (opcode) {
 830         case 0x0c: /* ldwu */
 831                 __asm__ __volatile__(
 832                 "1:     ldq_u %1,0(%3)\n"
 833                 "2:     ldq_u %2,1(%3)\n"
 834                 "       extwl %1,%3,%1\n"
 835                 "       extwh %2,%3,%2\n"
 836                 "3:\n"
 837                 ".section __ex_table,\"a\"\n"
 838                 "       .long 1b - .\n"
 839                 "       lda %1,3b-1b(%0)\n"
 840                 "       .long 2b - .\n"
 841                 "       lda %2,3b-2b(%0)\n"
 842                 ".previous"
 843                         : "=r"(error), "=&r"(tmp1), "=&r"(tmp2)
 844                         : "r"(va), "0"(0));
 845                 if (error)
 846                         goto give_sigsegv;
 847                 *reg_addr = tmp1|tmp2;
 848                 break;
 849
 850         case 0x22: /* lds */
 851                 __asm__ __volatile__(
 852                 "1:     ldq_u %1,0(%3)\n"
 853                 "2:     ldq_u %2,3(%3)\n"
 854                 "       extll %1,%3,%1\n"
 855                 "       extlh %2,%3,%2\n"
 856                 "3:\n"
 857                 ".section __ex_table,\"a\"\n"
 858                 "       .long 1b - .\n"
 859                 "       lda %1,3b-1b(%0)\n"
 860                 "       .long 2b - .\n"
 861                 "       lda %2,3b-2b(%0)\n"
 862                 ".previous"
 863                         : "=r"(error), "=&r"(tmp1), "=&r"(tmp2)
 864                         : "r"(va), "0"(0));
 865                 if (error)
 866                         goto give_sigsegv;
 867                 alpha_write_fp_reg(reg, s_mem_to_reg((int)(tmp1|tmp2)));
 868                 return;
 869
 870         case 0x23: /* ldt */
 871                 __asm__ __volatile__(
 872                 "1:     ldq_u %1,0(%3)\n"
 873                 "2:     ldq_u %2,7(%3)\n"
 874                 "       extql %1,%3,%1\n"
 875                 "       extqh %2,%3,%2\n"
 876                 "3:\n"
 877                 ".section __ex_table,\"a\"\n"
 878                 "       .long 1b - .\n"
 879                 "       lda %1,3b-1b(%0)\n"
 880                 "       .long 2b - .\n"
 881                 "       lda %2,3b-2b(%0)\n"
 882                 ".previous"
 883                         : "=r"(error), "=&r"(tmp1), "=&r"(tmp2)
 884                         : "r"(va), "0"(0));
 885                 if (error)
 886                         goto give_sigsegv;
 887                 alpha_write_fp_reg(reg, tmp1|tmp2);
 888                 return;
 889
 890         case 0x28: /* ldl */
 891                 __asm__ __volatile__(
 892                 "1:     ldq_u %1,0(%3)\n"
 893                 "2:     ldq_u %2,3(%3)\n"
 894                 "       extll %1,%3,%1\n"
 895                 "       extlh %2,%3,%2\n"
 896                 "3:\n"
 897                 ".section __ex_table,\"a\"\n"
 898                 "       .long 1b - .\n"
 899                 "       lda %1,3b-1b(%0)\n"
 900                 "       .long 2b - .\n"
 901                 "       lda %2,3b-2b(%0)\n"
 902                 ".previous"
 903                         : "=r"(error), "=&r"(tmp1), "=&r"(tmp2)
 904                         : "r"(va), "0"(0));
 905                 if (error)
 906                         goto give_sigsegv;
 907                 *reg_addr = (int)(tmp1|tmp2);
 908                 break;
 909
 910         case 0x29: /* ldq */
 911                 __asm__ __volatile__(
 912                 "1:     ldq_u %1,0(%3)\n"
 913                 "2:     ldq_u %2,7(%3)\n"
 914                 "       extql %1,%3,%1\n"
 915                 "       extqh %2,%3,%2\n"
 916                 "3:\n"
 917                 ".section __ex_table,\"a\"\n"
 918                 "       .long 1b - .\n"
 919                 "       lda %1,3b-1b(%0)\n"
 920                 "       .long 2b - .\n"
 921                 "       lda %2,3b-2b(%0)\n"
 922                 ".previous"
 923                         : "=r"(error), "=&r"(tmp1), "=&r"(tmp2)
 924                         : "r"(va), "0"(0));
 925                 if (error)
 926                         goto give_sigsegv;
 927                 *reg_addr = tmp1|tmp2;
 928                 break;
 929
 930         /* Note that the store sequences do not indicate that they change
 931            memory because it _should_ be affecting nothing in this context.
 932            (Otherwise we have other, much larger, problems.)  */
 933         case 0x0d: /* stw */
 934                 __asm__ __volatile__(
 935                 "1:     ldq_u %2,1(%5)\n"
 936                 "2:     ldq_u %1,0(%5)\n"
 937                 "       inswh %6,%5,%4\n"
 938                 "       inswl %6,%5,%3\n"
 939                 "       mskwh %2,%5,%2\n"
 940                 "       mskwl %1,%5,%1\n"
 941                 "       or %2,%4,%2\n"
 942                 "       or %1,%3,%1\n"
 943                 "3:     stq_u %2,1(%5)\n"
 944                 "4:     stq_u %1,0(%5)\n"
 945                 "5:\n"
 946                 ".section __ex_table,\"a\"\n"
 947                 "       .long 1b - .\n"
 948                 "       lda %2,5b-1b(%0)\n"
 949                 "       .long 2b - .\n"
 950                 "       lda %1,5b-2b(%0)\n"
 951                 "       .long 3b - .\n"
 952                 "       lda $31,5b-3b(%0)\n"
 953                 "       .long 4b - .\n"
 954                 "       lda $31,5b-4b(%0)\n"
 955                 ".previous"
 956                         : "=r"(error), "=&r"(tmp1), "=&r"(tmp2),
 957                           "=&r"(tmp3), "=&r"(tmp4)
 958                         : "r"(va), "r"(*reg_addr), "0"(0));
 959                 if (error)
 960                         goto give_sigsegv;
 961                 return;
 962
 963         case 0x26: /* sts */
 964                 fake_reg = s_reg_to_mem(alpha_read_fp_reg(reg));
 965                 /* FALLTHRU */
 966
 967         case 0x2c: /* stl */
 968                 __asm__ __volatile__(
 969                 "1:     ldq_u %2,3(%5)\n"
 970                 "2:     ldq_u %1,0(%5)\n"
 971                 "       inslh %6,%5,%4\n"
 972                 "       insll %6,%5,%3\n"
 973                 "       msklh %2,%5,%2\n"
 974                 "       mskll %1,%5,%1\n"
 975                 "       or %2,%4,%2\n"
 976                 "       or %1,%3,%1\n"
 977                 "3:     stq_u %2,3(%5)\n"
 978                 "4:     stq_u %1,0(%5)\n"
 979                 "5:\n"
 980                 ".section __ex_table,\"a\"\n"
 981                 "       .long 1b - .\n"
 982                 "       lda %2,5b-1b(%0)\n"
 983                 "       .long 2b - .\n"
 984                 "       lda %1,5b-2b(%0)\n"
 985                 "       .long 3b - .\n"
 986                 "       lda $31,5b-3b(%0)\n"
 987                 "       .long 4b - .\n"
 988                 "       lda $31,5b-4b(%0)\n"
 989                 ".previous"
 990                         : "=r"(error), "=&r"(tmp1), "=&r"(tmp2),
 991                           "=&r"(tmp3), "=&r"(tmp4)
 992                         : "r"(va), "r"(*reg_addr), "0"(0));
 993                 if (error)
 994                         goto give_sigsegv;
 995                 return;
 996
 997         case 0x27: /* stt */
 998                 fake_reg = alpha_read_fp_reg(reg);
 999                 /* FALLTHRU */
1000
1001         case 0x2d: /* stq */
1002                 __asm__ __volatile__(
1003                 "1:     ldq_u %2,7(%5)\n"
1004                 "2:     ldq_u %1,0(%5)\n"
1005                 "       insqh %6,%5,%4\n"
1006                 "       insql %6,%5,%3\n"
1007                 "       mskqh %2,%5,%2\n"
1008                 "       mskql %1,%5,%1\n"
1009                 "       or %2,%4,%2\n"
1010                 "       or %1,%3,%1\n"
1011                 "3:     stq_u %2,7(%5)\n"
1012                 "4:     stq_u %1,0(%5)\n"
1013                 "5:\n"
1014                 ".section __ex_table,\"a\"\n\t"
1015                 "       .long 1b - .\n"
1016                 "       lda %2,5b-1b(%0)\n"
1017                 "       .long 2b - .\n"
1018                 "       lda %1,5b-2b(%0)\n"
1019                 "       .long 3b - .\n"
1020                 "       lda $31,5b-3b(%0)\n"
1021                 "       .long 4b - .\n"
1022                 "       lda $31,5b-4b(%0)\n"
1023                 ".previous"
1024                         : "=r"(error), "=&r"(tmp1), "=&r"(tmp2),
1025                           "=&r"(tmp3), "=&r"(tmp4)
1026                         : "r"(va), "r"(*reg_addr), "0"(0));
1027                 if (error)
1028                         goto give_sigsegv;
1029                 return;
1030
1031         default:
1032                 /* What instruction were you trying to use, exactly?  */
1033                 goto give_sigbus;
1034         }
1035
1036         /* Only integer loads should get here; everyone else returns early. */
1037         if (reg == 30)
1038                 wrusp(fake_reg);
1039         return;
1040
1041 give_sigsegv:
1042         regs->pc -= 4;  /* make pc point to faulting insn */
1043         info.si_signo = SIGSEGV;
1044         info.si_errno = 0;
1045
1046         /* We need to replicate some of the logic in mm/fault.c,
1047            since we don't have access to the fault code in the
1048            exception handling return path.  */
1049         if (!__access_ok((unsigned long)va, 0, USER_DS))
1050                 info.si_code = SEGV_ACCERR;
1051         else {
1052                 struct mm_struct *mm = current->mm;
1053                 down_read(&mm->mmap_sem);
1054                 if (find_vma(mm, (unsigned long)va))
1055                         info.si_code = SEGV_ACCERR;
1056                 else
1057                         info.si_code = SEGV_MAPERR;
1058                 up_read(&mm->mmap_sem);
1059         }
1060         info.si_addr = va;
1061         send_sig_info(SIGSEGV, &info, current);
1062         return;
1063
1064 give_sigbus:
1065         regs->pc -= 4;
1066         info.si_signo = SIGBUS;
1067         info.si_errno = 0;
1068         info.si_code = BUS_ADRALN;
1069         info.si_addr = va;
1070         send_sig_info(SIGBUS, &info, current);
1071         return;
1072 }
1073
1074 void __init
1075 trap_init(void)
1076 {
1077         /* Tell PAL-code what global pointer we want in the kernel.  */
1078         register unsigned long gptr __asm__("$29");
1079         wrkgp(gptr);
1080
1081         /* Hack for Multia (UDB) and JENSEN: some of their SRMs have
1082            a bug in the handling of the opDEC fault.  Fix it up if so.  */
1083         if (implver() == IMPLVER_EV4)
1084                 opDEC_check();
1085
1086         wrent(entArith, 1);
1087         wrent(entMM, 2);
1088         wrent(entIF, 3);
1089         wrent(entUna, 4);
1090         wrent(entSys, 5);
1091         wrent(entDbg, 6);
1092 }