sys/powerpc/powerpc/trap.c

   1 /*-
   2  * Copyright (C) 1995, 1996 Wolfgang Solfrank.
   3  * Copyright (C) 1995, 1996 TooLs GmbH.
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  * 3. All advertising materials mentioning features or use of this software
  15  *    must display the following acknowledgement:
  16  *      This product includes software developed by TooLs GmbH.
  17  * 4. The name of TooLs GmbH may not be used to endorse or promote products
  18  *    derived from this software without specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR
  21  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  22  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  23  * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  24  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  25  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
  26  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
  27  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
  28  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
  29  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  30  *
  31  * $NetBSD: trap.c,v 1.58 2002/03/04 04:07:35 dbj Exp $
  32  */
  33
  34 #include <sys/cdefs.h>
  35 __FBSDID("$FreeBSD$");
  36
  37 #include <sys/param.h>
  38 #include <sys/kdb.h>
  39 #include <sys/proc.h>
  40 #include <sys/ktr.h>
  41 #include <sys/lock.h>
  42 #include <sys/mutex.h>
  43 #include <sys/pioctl.h>
  44 #include <sys/ptrace.h>
  45 #include <sys/reboot.h>
  46 #include <sys/syscall.h>
  47 #include <sys/sysent.h>
  48 #include <sys/systm.h>
  49 #include <sys/kernel.h>
  50 #include <sys/uio.h>
  51 #include <sys/signalvar.h>
  52 #include <sys/vmmeter.h>
  53
  54 #include <security/audit/audit.h>
  55
  56 #include <vm/vm.h>
  57 #include <vm/pmap.h>
  58 #include <vm/vm_extern.h>
  59 #include <vm/vm_param.h>
  60 #include <vm/vm_kern.h>
  61 #include <vm/vm_map.h>
  62 #include <vm/vm_page.h>
  63
  64 #include <machine/_inttypes.h>
  65 #include <machine/altivec.h>
  66 #include <machine/cpu.h>
  67 #include <machine/db_machdep.h>
  68 #include <machine/fpu.h>
  69 #include <machine/frame.h>
  70 #include <machine/pcb.h>
  71 #include <machine/psl.h>
  72 #include <machine/trap.h>
  73 #include <machine/spr.h>
  74 #include <machine/sr.h>
  75
  76 /* Below matches setjmp.S */
  77 #define FAULTBUF_LR     21
  78 #define FAULTBUF_R1     1
  79 #define FAULTBUF_R2     2
  80 #define FAULTBUF_CR     22
  81 #define FAULTBUF_R14    3
  82
  83 static void     trap_fatal(struct trapframe *frame);
  84 static void     printtrap(u_int vector, struct trapframe *frame, int isfatal,
  85                     int user);
  86 static int      trap_pfault(struct trapframe *frame, int user);
  87 static int      fix_unaligned(struct thread *td, struct trapframe *frame);
  88 static int      handle_onfault(struct trapframe *frame);
  89 static void     syscall(struct trapframe *frame);
  90
  91 #ifdef __powerpc64__
  92        void     handle_kernel_slb_spill(int, register_t, register_t);
  93 static int      handle_user_slb_spill(pmap_t pm, vm_offset_t addr);
  94 extern int      n_slbs;
  95 #endif
  96
  97 struct powerpc_exception {
  98         u_int   vector;
  99         char    *name;
 100 };
 101
 102 #ifdef KDTRACE_HOOKS
 103 #include <sys/dtrace_bsd.h>
 104
 105 int (*dtrace_invop_jump_addr)(struct trapframe *);
 106 #endif
 107
 108 static struct powerpc_exception powerpc_exceptions[] = {
 109         { EXC_CRIT,     "critical input" },
 110         { EXC_RST,      "system reset" },
 111         { EXC_MCHK,     "machine check" },
 112         { EXC_DSI,      "data storage interrupt" },
 113         { EXC_DSE,      "data segment exception" },
 114         { EXC_ISI,      "instruction storage interrupt" },
 115         { EXC_ISE,      "instruction segment exception" },
 116         { EXC_EXI,      "external interrupt" },
 117         { EXC_ALI,      "alignment" },
 118         { EXC_PGM,      "program" },
 119         { EXC_FPU,      "floating-point unavailable" },
 120         { EXC_APU,      "auxiliary proc unavailable" },
 121         { EXC_DECR,     "decrementer" },
 122         { EXC_FIT,      "fixed-interval timer" },
 123         { EXC_WDOG,     "watchdog timer" },
 124         { EXC_SC,       "system call" },
 125         { EXC_TRC,      "trace" },
 126         { EXC_FPA,      "floating-point assist" },
 127         { EXC_DEBUG,    "debug" },
 128         { EXC_PERF,     "performance monitoring" },
 129         { EXC_VEC,      "altivec unavailable" },
 130         { EXC_VSX,      "vsx unavailable" },
 131         { EXC_ITMISS,   "instruction tlb miss" },
 132         { EXC_DLMISS,   "data load tlb miss" },
 133         { EXC_DSMISS,   "data store tlb miss" },
 134         { EXC_BPT,      "instruction breakpoint" },
 135         { EXC_SMI,      "system management" },
 136         { EXC_VECAST_G4,        "altivec assist" },
 137         { EXC_THRM,     "thermal management" },
 138         { EXC_RUNMODETRC,       "run mode/trace" },
 139         { EXC_LAST,     NULL }
 140 };
 141
 142 static const char *
 143 trapname(u_int vector)
 144 {
 145         struct  powerpc_exception *pe;
 146
 147         for (pe = powerpc_exceptions; pe->vector != EXC_LAST; pe++) {
 148                 if (pe->vector == vector)
 149                         return (pe->name);
 150         }
 151
 152         return ("unknown");
 153 }
 154
 155 void
 156 trap(struct trapframe *frame)
 157 {
 158         struct thread   *td;
 159         struct proc     *p;
 160 #ifdef KDTRACE_HOOKS
 161         uint32_t inst;
 162 #endif
 163         int             sig, type, user;
 164         u_int           ucode;
 165         ksiginfo_t      ksi;
 166
 167         PCPU_INC(cnt.v_trap);
 168
 169         td = curthread;
 170         p = td->td_proc;
 171
 172         type = ucode = frame->exc;
 173         sig = 0;
 174         user = frame->srr1 & PSL_PR;
 175
 176         CTR3(KTR_TRAP, "trap: %s type=%s (%s)", td->td_name,
 177             trapname(type), user ? "user" : "kernel");
 178
 179 #ifdef KDTRACE_HOOKS
 180         /*
 181          * A trap can occur while DTrace executes a probe. Before
 182          * executing the probe, DTrace blocks re-scheduling and sets
 183          * a flag in its per-cpu flags to indicate that it doesn't
 184          * want to fault. On returning from the probe, the no-fault
 185          * flag is cleared and finally re-scheduling is enabled.
 186          *
 187          * If the DTrace kernel module has registered a trap handler,
 188          * call it and if it returns non-zero, assume that it has
 189          * handled the trap and modified the trap frame so that this
 190          * function can return normally.
 191          */
 192         if (dtrace_trap_func != NULL && (*dtrace_trap_func)(frame, type) != 0)
 193                 return;
 194 #endif
 195
 196         if (user) {
 197                 td->td_pticks = 0;
 198                 td->td_frame = frame;
 199                 if (td->td_cowgen != p->p_cowgen)
 200                         thread_cow_update(td);
 201
 202                 /* User Mode Traps */
 203                 switch (type) {
 204                 case EXC_RUNMODETRC:
 205                 case EXC_TRC:
 206                         frame->srr1 &= ~PSL_SE;
 207                         sig = SIGTRAP;
 208                         ucode = TRAP_TRACE;
 209                         break;
 210
 211 #ifdef __powerpc64__
 212                 case EXC_ISE:
 213                 case EXC_DSE:
 214                         if (handle_user_slb_spill(&p->p_vmspace->vm_pmap,
 215                             (type == EXC_ISE) ? frame->srr0 : frame->dar) != 0){
 216                                 sig = SIGSEGV;
 217                                 ucode = SEGV_MAPERR;
 218                         }
 219                         break;
 220 #endif
 221                 case EXC_DSI:
 222                 case EXC_ISI:
 223                         sig = trap_pfault(frame, 1);
 224                         if (sig == SIGSEGV)
 225                                 ucode = SEGV_MAPERR;
 226                         break;
 227
 228                 case EXC_SC:
 229                         syscall(frame);
 230                         break;
 231
 232                 case EXC_FPU:
 233                         KASSERT((td->td_pcb->pcb_flags & PCB_FPU) != PCB_FPU,
 234                             ("FPU already enabled for thread"));
 235                         enable_fpu(td);
 236                         break;
 237
 238                 case EXC_VEC:
 239                         KASSERT((td->td_pcb->pcb_flags & PCB_VEC) != PCB_VEC,
 240                             ("Altivec already enabled for thread"));
 241                         enable_vec(td);
 242                         break;
 243
 244                 case EXC_VSX:
 245                         KASSERT((td->td_pcb->pcb_flags & PCB_VSX) != PCB_VSX,
 246                             ("VSX already enabled for thread"));
 247                         if (!(td->td_pcb->pcb_flags & PCB_VEC))
 248                                 enable_vec(td);
 249                         if (!(td->td_pcb->pcb_flags & PCB_FPU))
 250                                 save_fpu(td);
 251                         td->td_pcb->pcb_flags |= PCB_VSX;
 252                         enable_fpu(td);
 253                         break;
 254
 255                 case EXC_VECAST_E:
 256                 case EXC_VECAST_G4:
 257                 case EXC_VECAST_G5:
 258                         /*
 259                          * We get a VPU assist exception for IEEE mode
 260                          * vector operations on denormalized floats.
 261                          * Emulating this is a giant pain, so for now,
 262                          * just switch off IEEE mode and treat them as
 263                          * zero.
 264                          */
 265
 266                         save_vec(td);
 267                         td->td_pcb->pcb_vec.vscr |= ALTIVEC_VSCR_NJ;
 268                         enable_vec(td);
 269                         break;
 270
 271                 case EXC_ALI:
 272                         if (fix_unaligned(td, frame) != 0) {
 273                                 sig = SIGBUS;
 274                                 ucode = BUS_ADRALN;
 275                         }
 276                         else
 277                                 frame->srr0 += 4;
 278                         break;
 279
 280                 case EXC_DEBUG: /* Single stepping */
 281                         mtspr(SPR_DBSR, mfspr(SPR_DBSR));
 282                         frame->srr1 &= ~PSL_DE;
 283                         frame->cpu.booke.dbcr0 &= ~(DBCR0_IDM || DBCR0_IC);
 284                         sig = SIGTRAP;
 285                         ucode = TRAP_TRACE;
 286                         break;
 287
 288                 case EXC_PGM:
 289                         /* Identify the trap reason */
 290 #ifdef AIM
 291                         if (frame->srr1 & EXC_PGM_TRAP) {
 292 #else
 293                         if (frame->cpu.booke.esr & ESR_PTR) {
 294 #endif
 295 #ifdef KDTRACE_HOOKS
 296                                 inst = fuword32((const void *)frame->srr0);
 297                                 if (inst == 0x0FFFDDDD &&
 298                                     dtrace_pid_probe_ptr != NULL) {
 299                                         struct reg regs;
 300                                         fill_regs(td, &regs);
 301                                         (*dtrace_pid_probe_ptr)(&regs);
 302                                         break;
 303                                 }
 304 #endif
 305                                 sig = SIGTRAP;
 306                                 ucode = TRAP_BRKPT;
 307                         } else {
 308                                 sig = ppc_instr_emulate(frame, td->td_pcb);
 309                                 if (sig == SIGILL) {
 310                                         if (frame->srr1 & EXC_PGM_PRIV)
 311                                                 ucode = ILL_PRVOPC;
 312                                         else if (frame->srr1 & EXC_PGM_ILLEGAL)
 313                                                 ucode = ILL_ILLOPC;
 314                                 } else if (sig == SIGFPE)
 315                                         ucode = FPE_FLTINV;     /* Punt for now, invalid operation. */
 316                         }
 317                         break;
 318
 319                 case EXC_MCHK:
 320                         /*
 321                          * Note that this may not be recoverable for the user
 322                          * process, depending on the type of machine check,
 323                          * but it at least prevents the kernel from dying.
 324                          */
 325                         sig = SIGBUS;
 326                         ucode = BUS_OBJERR;
 327                         break;
 328
 329                 default:
 330                         trap_fatal(frame);
 331                 }
 332         } else {
 333                 /* Kernel Mode Traps */
 334
 335                 KASSERT(cold || td->td_ucred != NULL,
 336                     ("kernel trap doesn't have ucred"));
 337                 switch (type) {
 338 #ifdef KDTRACE_HOOKS
 339                 case EXC_PGM:
 340                         if (frame->srr1 & EXC_PGM_TRAP) {
 341                                 if (*(uint32_t *)frame->srr0 == EXC_DTRACE) {
 342                                         if (dtrace_invop_jump_addr != NULL) {
 343                                                 dtrace_invop_jump_addr(frame);
 344                                                 return;
 345                                         }
 346                                 }
 347                         }
 348                         break;
 349 #endif
 350 #ifdef __powerpc64__
 351                 case EXC_DSE:
 352                         if ((frame->dar & SEGMENT_MASK) == USER_ADDR) {
 353                                 __asm __volatile ("slbmte %0, %1" ::
 354                                         "r"(td->td_pcb->pcb_cpu.aim.usr_vsid),
 355                                         "r"(USER_SLB_SLBE));
 356                                 return;
 357                         }
 358                         break;
 359 #endif
 360                 case EXC_DSI:
 361                         if (trap_pfault(frame, 0) == 0)
 362                                 return;
 363                         break;
 364                 case EXC_MCHK:
 365                         if (handle_onfault(frame))
 366                                 return;
 367                         break;
 368                 default:
 369                         break;
 370                 }
 371                 trap_fatal(frame);
 372         }
 373
 374         if (sig != 0) {
 375                 if (p->p_sysent->sv_transtrap != NULL)
 376                         sig = (p->p_sysent->sv_transtrap)(sig, type);
 377                 ksiginfo_init_trap(&ksi);
 378                 ksi.ksi_signo = sig;
 379                 ksi.ksi_code = (int) ucode; /* XXX, not POSIX */
 380                 /* ksi.ksi_addr = ? */
 381                 ksi.ksi_trapno = type;
 382                 trapsignal(td, &ksi);
 383         }
 384
 385         userret(td, frame);
 386 }
 387
 388 static void
 389 trap_fatal(struct trapframe *frame)
 390 {
 391
 392         printtrap(frame->exc, frame, 1, (frame->srr1 & PSL_PR));
 393 #ifdef KDB
 394         if ((debugger_on_panic || kdb_active) &&
 395             kdb_trap(frame->exc, 0, frame))
 396                 return;
 397 #endif
 398         panic("%s trap", trapname(frame->exc));
 399 }
 400
 401 static void
 402 printtrap(u_int vector, struct trapframe *frame, int isfatal, int user)
 403 {
 404         uint16_t ver;
 405 #ifdef BOOKE
 406         vm_paddr_t pa;
 407 #endif
 408
 409         printf("\n");
 410         printf("%s %s trap:\n", isfatal ? "fatal" : "handled",
 411             user ? "user" : "kernel");
 412         printf("\n");
 413         printf("   exception       = 0x%x (%s)\n", vector, trapname(vector));
 414         switch (vector) {
 415         case EXC_DSE:
 416         case EXC_DSI:
 417         case EXC_DTMISS:
 418                 printf("   virtual address = 0x%" PRIxPTR "\n", frame->dar);
 419 #ifdef AIM
 420                 printf("   dsisr           = 0x%lx\n",
 421                     (u_long)frame->cpu.aim.dsisr);
 422 #endif
 423                 break;
 424         case EXC_ISE:
 425         case EXC_ISI:
 426         case EXC_ITMISS:
 427                 printf("   virtual address = 0x%" PRIxPTR "\n", frame->srr0);
 428                 break;
 429         case EXC_MCHK:
 430                 ver = mfpvr() >> 16;
 431 #if defined(AIM)
 432                 if (MPC745X_P(ver))
 433                         printf("    msssr0         = 0x%lx\n",
 434                             (u_long)mfspr(SPR_MSSSR0));
 435 #elif defined(BOOKE)
 436                 pa = mfspr(SPR_MCARU);
 437                 pa = (pa << 32) | mfspr(SPR_MCAR);
 438                 printf("   mcsr            = 0x%lx\n", (u_long)mfspr(SPR_MCSR));
 439                 printf("   mcar            = 0x%jx\n", (uintmax_t)pa);
 440 #endif
 441                 break;
 442         }
 443 #ifdef BOOKE
 444         printf("   esr             = 0x%" PRIxPTR "\n",
 445             frame->cpu.booke.esr);
 446 #endif
 447         printf("   srr0            = 0x%" PRIxPTR "\n", frame->srr0);
 448         printf("   srr1            = 0x%lx\n", (u_long)frame->srr1);
 449         printf("   lr              = 0x%" PRIxPTR "\n", frame->lr);
 450         printf("   curthread       = %p\n", curthread);
 451         if (curthread != NULL)
 452                 printf("          pid = %d, comm = %s\n",
 453                     curthread->td_proc->p_pid, curthread->td_name);
 454         printf("\n");
 455 }
 456
 457 /*
 458  * Handles a fatal fault when we have onfault state to recover.  Returns
 459  * non-zero if there was onfault recovery state available.
 460  */
 461 static int
 462 handle_onfault(struct trapframe *frame)
 463 {
 464         struct          thread *td;
 465         jmp_buf         *fb;
 466
 467         td = curthread;
 468         fb = td->td_pcb->pcb_onfault;
 469         if (fb != NULL) {
 470                 frame->srr0 = (*fb)->_jb[FAULTBUF_LR];
 471                 frame->fixreg[1] = (*fb)->_jb[FAULTBUF_R1];
 472                 frame->fixreg[2] = (*fb)->_jb[FAULTBUF_R2];
 473                 frame->fixreg[3] = 1;
 474                 frame->cr = (*fb)->_jb[FAULTBUF_CR];
 475                 bcopy(&(*fb)->_jb[FAULTBUF_R14], &frame->fixreg[14],
 476                     18 * sizeof(register_t));
 477                 td->td_pcb->pcb_onfault = NULL; /* Returns twice, not thrice */
 478                 return (1);
 479         }
 480         return (0);
 481 }
 482
 483 int
 484 cpu_fetch_syscall_args(struct thread *td, struct syscall_args *sa)
 485 {
 486         struct proc *p;
 487         struct trapframe *frame;
 488         caddr_t params;
 489         size_t argsz;
 490         int error, n, i;
 491
 492         p = td->td_proc;
 493         frame = td->td_frame;
 494
 495         sa->code = frame->fixreg[0];
 496         params = (caddr_t)(frame->fixreg + FIRSTARG);
 497         n = NARGREG;
 498
 499         if (sa->code == SYS_syscall) {
 500                 /*
 501                  * code is first argument,
 502                  * followed by actual args.
 503                  */
 504                 sa->code = *(register_t *) params;
 505                 params += sizeof(register_t);
 506                 n -= 1;
 507         } else if (sa->code == SYS___syscall) {
 508                 /*
 509                  * Like syscall, but code is a quad,
 510                  * so as to maintain quad alignment
 511                  * for the rest of the args.
 512                  */
 513                 if (SV_PROC_FLAG(p, SV_ILP32)) {
 514                         params += sizeof(register_t);
 515                         sa->code = *(register_t *) params;
 516                         params += sizeof(register_t);
 517                         n -= 2;
 518                 } else {
 519                         sa->code = *(register_t *) params;
 520                         params += sizeof(register_t);
 521                         n -= 1;
 522                 }
 523         }
 524
 525         if (p->p_sysent->sv_mask)
 526                 sa->code &= p->p_sysent->sv_mask;
 527         if (sa->code >= p->p_sysent->sv_size)
 528                 sa->callp = &p->p_sysent->sv_table[0];
 529         else
 530                 sa->callp = &p->p_sysent->sv_table[sa->code];
 531
 532         sa->narg = sa->callp->sy_narg;
 533
 534         if (SV_PROC_FLAG(p, SV_ILP32)) {
 535                 argsz = sizeof(uint32_t);
 536
 537                 for (i = 0; i < n; i++)
 538                         sa->args[i] = ((u_register_t *)(params))[i] &
 539                             0xffffffff;
 540         } else {
 541                 argsz = sizeof(uint64_t);
 542
 543                 for (i = 0; i < n; i++)
 544                         sa->args[i] = ((u_register_t *)(params))[i];
 545         }
 546
 547         if (sa->narg > n)
 548                 error = copyin(MOREARGS(frame->fixreg[1]), sa->args + n,
 549                                (sa->narg - n) * argsz);
 550         else
 551                 error = 0;
 552
 553 #ifdef __powerpc64__
 554         if (SV_PROC_FLAG(p, SV_ILP32) && sa->narg > n) {
 555                 /* Expand the size of arguments copied from the stack */
 556
 557                 for (i = sa->narg; i >= n; i--)
 558                         sa->args[i] = ((uint32_t *)(&sa->args[n]))[i-n];
 559         }
 560 #endif
 561
 562         if (error == 0) {
 563                 td->td_retval[0] = 0;
 564                 td->td_retval[1] = frame->fixreg[FIRSTARG + 1];
 565         }
 566         return (error);
 567 }
 568
 569 #include "../../kern/subr_syscall.c"
 570
 571 void
 572 syscall(struct trapframe *frame)
 573 {
 574         struct thread *td;
 575         struct syscall_args sa;
 576         int error;
 577
 578         td = curthread;
 579         td->td_frame = frame;
 580
 581 #ifdef __powerpc64__
 582         /*
 583          * Speculatively restore last user SLB segment, which we know is
 584          * invalid already, since we are likely to do copyin()/copyout().
 585          */
 586         __asm __volatile ("slbmte %0, %1; isync" ::
 587             "r"(td->td_pcb->pcb_cpu.aim.usr_vsid), "r"(USER_SLB_SLBE));
 588 #endif
 589
 590         error = syscallenter(td, &sa);
 591         syscallret(td, error, &sa);
 592 }
 593
 594 #ifdef __powerpc64__
 595 /* Handle kernel SLB faults -- runs in real mode, all seat belts off */
 596 void
 597 handle_kernel_slb_spill(int type, register_t dar, register_t srr0)
 598 {
 599         struct slb *slbcache;
 600         uint64_t slbe, slbv;
 601         uint64_t esid, addr;
 602         int i;
 603
 604         addr = (type == EXC_ISE) ? srr0 : dar;
 605         slbcache = PCPU_GET(slb);
 606         esid = (uintptr_t)addr >> ADDR_SR_SHFT;
 607         slbe = (esid << SLBE_ESID_SHIFT) | SLBE_VALID;
 608
 609         /* See if the hardware flushed this somehow (can happen in LPARs) */
 610         for (i = 0; i < n_slbs; i++)
 611                 if (slbcache[i].slbe == (slbe | (uint64_t)i))
 612                         return;
 613
 614         /* Not in the map, needs to actually be added */
 615         slbv = kernel_va_to_slbv(addr);
 616         if (slbcache[USER_SLB_SLOT].slbe == 0) {
 617                 for (i = 0; i < n_slbs; i++) {
 618                         if (i == USER_SLB_SLOT)
 619                                 continue;
 620                         if (!(slbcache[i].slbe & SLBE_VALID))
 621                                 goto fillkernslb;
 622                 }
 623
 624                 if (i == n_slbs)
 625                         slbcache[USER_SLB_SLOT].slbe = 1;
 626         }
 627
 628         /* Sacrifice a random SLB entry that is not the user entry */
 629         i = mftb() % n_slbs;
 630         if (i == USER_SLB_SLOT)
 631                 i = (i+1) % n_slbs;
 632
 633 fillkernslb:
 634         /* Write new entry */
 635         slbcache[i].slbv = slbv;
 636         slbcache[i].slbe = slbe | (uint64_t)i;
 637
 638         /* Trap handler will restore from cache on exit */
 639 }
 640
 641 static int
 642 handle_user_slb_spill(pmap_t pm, vm_offset_t addr)
 643 {
 644         struct slb *user_entry;
 645         uint64_t esid;
 646         int i;
 647
 648         esid = (uintptr_t)addr >> ADDR_SR_SHFT;
 649
 650         PMAP_LOCK(pm);
 651         user_entry = user_va_to_slb_entry(pm, addr);
 652
 653         if (user_entry == NULL) {
 654                 /* allocate_vsid auto-spills it */
 655                 (void)allocate_user_vsid(pm, esid, 0);
 656         } else {
 657                 /*
 658                  * Check that another CPU has not already mapped this.
 659                  * XXX: Per-thread SLB caches would be better.
 660                  */
 661                 for (i = 0; i < pm->pm_slb_len; i++)
 662                         if (pm->pm_slb[i] == user_entry)
 663                                 break;
 664
 665                 if (i == pm->pm_slb_len)
 666                         slb_insert_user(pm, user_entry);
 667         }
 668         PMAP_UNLOCK(pm);
 669
 670         return (0);
 671 }
 672 #endif
 673
 674 static int
 675 trap_pfault(struct trapframe *frame, int user)
 676 {
 677         vm_offset_t     eva, va;
 678         struct          thread *td;
 679         struct          proc *p;
 680         vm_map_t        map;
 681         vm_prot_t       ftype;
 682         int             rv;
 683 #ifdef AIM
 684         register_t      user_sr;
 685 #endif
 686
 687         td = curthread;
 688         p = td->td_proc;
 689         if (frame->exc == EXC_ISI) {
 690                 eva = frame->srr0;
 691                 ftype = VM_PROT_EXECUTE;
 692                 if (frame->srr1 & SRR1_ISI_PFAULT)
 693                         ftype |= VM_PROT_READ;
 694         } else {
 695                 eva = frame->dar;
 696 #ifdef BOOKE
 697                 if (frame->cpu.booke.esr & ESR_ST)
 698 #else
 699                 if (frame->cpu.aim.dsisr & DSISR_STORE)
 700 #endif
 701                         ftype = VM_PROT_WRITE;
 702                 else
 703                         ftype = VM_PROT_READ;
 704         }
 705
 706         if (user) {
 707                 KASSERT(p->p_vmspace != NULL, ("trap_pfault: vmspace  NULL"));
 708                 map = &p->p_vmspace->vm_map;
 709         } else {
 710 #ifdef BOOKE
 711                 if (eva < VM_MAXUSER_ADDRESS) {
 712 #else
 713                 if ((eva >> ADDR_SR_SHFT) == (USER_ADDR >> ADDR_SR_SHFT)) {
 714 #endif
 715                         map = &p->p_vmspace->vm_map;
 716
 717 #ifdef AIM
 718                         user_sr = td->td_pcb->pcb_cpu.aim.usr_segm;
 719                         eva &= ADDR_PIDX | ADDR_POFF;
 720                         eva |= user_sr << ADDR_SR_SHFT;
 721 #endif
 722                 } else {
 723                         map = kernel_map;
 724                 }
 725         }
 726         va = trunc_page(eva);
 727
 728         /* Fault in the page. */
 729         rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL);
 730         /*
 731          * XXXDTRACE: add dtrace_doubletrap_func here?
 732          */
 733
 734         if (rv == KERN_SUCCESS)
 735                 return (0);
 736
 737         if (!user && handle_onfault(frame))
 738                 return (0);
 739
 740         return (SIGSEGV);
 741 }
 742
 743 /*
 744  * For now, this only deals with the particular unaligned access case
 745  * that gcc tends to generate.  Eventually it should handle all of the
 746  * possibilities that can happen on a 32-bit PowerPC in big-endian mode.
 747  */
 748
 749 static int
 750 fix_unaligned(struct thread *td, struct trapframe *frame)
 751 {
 752         struct thread   *fputhread;
 753         int             indicator, reg;
 754         double          *fpr;
 755
 756         indicator = EXC_ALI_OPCODE_INDICATOR(frame->cpu.aim.dsisr);
 757
 758         switch (indicator) {
 759         case EXC_ALI_LFD:
 760         case EXC_ALI_STFD:
 761                 reg = EXC_ALI_RST(frame->cpu.aim.dsisr);
 762                 fpr = &td->td_pcb->pcb_fpu.fpr[reg].fpr;
 763                 fputhread = PCPU_GET(fputhread);
 764
 765                 /* Juggle the FPU to ensure that we've initialized
 766                  * the FPRs, and that their current state is in
 767                  * the PCB.
 768                  */
 769                 if (fputhread != td) {
 770                         if (fputhread)
 771                                 save_fpu(fputhread);
 772                         enable_fpu(td);
 773                 }
 774                 save_fpu(td);
 775
 776                 if (indicator == EXC_ALI_LFD) {
 777                         if (copyin((void *)frame->dar, fpr,
 778                             sizeof(double)) != 0)
 779                                 return (-1);
 780                         enable_fpu(td);
 781                 } else {
 782                         if (copyout(fpr, (void *)frame->dar,
 783                             sizeof(double)) != 0)
 784                                 return (-1);
 785                 }
 786                 return (0);
 787                 break;
 788         }
 789
 790         return (-1);
 791 }
 792
 793 #ifdef KDB
 794 int db_trap_glue(struct trapframe *);           /* Called from trap_subr.S */
 795
 796 int
 797 db_trap_glue(struct trapframe *frame)
 798 {
 799         if (!(frame->srr1 & PSL_PR)
 800             && (frame->exc == EXC_TRC || frame->exc == EXC_RUNMODETRC
 801 #ifdef AIM
 802                 || (frame->exc == EXC_PGM
 803                     && (frame->srr1 & EXC_PGM_TRAP))
 804 #else
 805                 || (frame->exc == EXC_DEBUG)
 806 #endif
 807                 || frame->exc == EXC_BPT
 808                 || frame->exc == EXC_DSI)) {
 809                 int type = frame->exc;
 810
 811                 /* Ignore DTrace traps. */
 812                 if (*(uint32_t *)frame->srr0 == EXC_DTRACE)
 813                         return (0);
 814 #ifdef AIM
 815                 if (type == EXC_PGM && (frame->srr1 & EXC_PGM_TRAP)) {
 816 #else
 817                 if (frame->cpu.booke.esr & ESR_PTR) {
 818 #endif
 819                         type = T_BREAKPOINT;
 820                 }
 821                 return (kdb_trap(type, 0, frame));
 822         }
 823
 824         return (0);
 825 }
 826 #endif