text: /*-
   * Copyright (C) 1995, 1996 Wolfgang Solfrank.
   * Copyright (C) 1995, 1996 TooLs GmbH.
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   * 3. All advertising materials mentioning features or use of this software
   *    must display the following acknowledgement:
   *	This product includes software developed by TooLs GmbH.
   * 4. The name of TooLs GmbH may not be used to endorse or promote products
   *    derived from this software without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR
   * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
   * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
   * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
   * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
   * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
   * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
   * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   *
   * $NetBSD: trap.c,v 1.58 2002/03/04 04:07:35 dbj Exp $
   */
  
  #include <sys/cdefs.h>
  __FBSDID("$FreeBSD$");
  
  #include <sys/param.h>
  #include <sys/kdb.h>
  #include <sys/proc.h>
  #include <sys/ktr.h>
  #include <sys/lock.h>
  #include <sys/mutex.h>
  #include <sys/pioctl.h>
  #include <sys/ptrace.h>
  #include <sys/reboot.h>
  #include <sys/syscall.h>
  #include <sys/sysent.h>
  #include <sys/systm.h>
  #include <sys/kernel.h>
  #include <sys/uio.h>
  #include <sys/signalvar.h>
  #include <sys/vmmeter.h>
  
  #include <security/audit/audit.h>
  
  #include <vm/vm.h>
  #include <vm/pmap.h>
  #include <vm/vm_extern.h>
  #include <vm/vm_param.h>
  #include <vm/vm_kern.h>
  #include <vm/vm_map.h>
  #include <vm/vm_page.h>
  
  #include <machine/_inttypes.h>
  #include <machine/altivec.h>
  #include <machine/cpu.h>
  #include <machine/db_machdep.h>
  #include <machine/fpu.h>
  #include <machine/frame.h>
  #include <machine/pcb.h>
  #include <machine/psl.h>
  #include <machine/trap.h>
  #include <machine/spr.h>
  #include <machine/sr.h>
  
  /* Below matches setjmp.S */
  #define	FAULTBUF_LR	21
  #define	FAULTBUF_R1	1
  #define	FAULTBUF_R2	2
  #define	FAULTBUF_CR	22
  #define	FAULTBUF_R14	3
  
  static void	trap_fatal(struct trapframe *frame);
  static void	printtrap(u_int vector, struct trapframe *frame, int isfatal,
  		    int user);
  static int	trap_pfault(struct trapframe *frame, int user);
  static int	fix_unaligned(struct thread *td, struct trapframe *frame);
  static int	handle_onfault(struct trapframe *frame);
  static void	syscall(struct trapframe *frame);
  
  #ifdef __powerpc64__
         void	handle_kernel_slb_spill(int, register_t, register_t);
  static int	handle_user_slb_spill(pmap_t pm, vm_offset_t addr);
  extern int	n_slbs;
  #endif
  
  struct powerpc_exception {
  	u_int	vector;
  	char	*name;
  };
  
  #ifdef KDTRACE_HOOKS
  #include <sys/dtrace_bsd.h>
  
  int (*dtrace_invop_jump_addr)(struct trapframe *);
  #endif
  
  static struct powerpc_exception powerpc_exceptions[] = {
  	{ EXC_CRIT,	"critical input" },
  	{ EXC_RST,	"system reset" },
  	{ EXC_MCHK,	"machine check" },
  	{ EXC_DSI,	"data storage interrupt" },
  	{ EXC_DSE,	"data segment exception" },
  	{ EXC_ISI,	"instruction storage interrupt" },
  	{ EXC_ISE,	"instruction segment exception" },
  	{ EXC_EXI,	"external interrupt" },
  	{ EXC_ALI,	"alignment" },
  	{ EXC_PGM,	"program" },
  	{ EXC_FPU,	"floating-point unavailable" },
  	{ EXC_APU,	"auxiliary proc unavailable" },
  	{ EXC_DECR,	"decrementer" },
  	{ EXC_FIT,	"fixed-interval timer" },
  	{ EXC_WDOG,	"watchdog timer" },
  	{ EXC_SC,	"system call" },
  	{ EXC_TRC,	"trace" },
  	{ EXC_FPA,	"floating-point assist" },
  	{ EXC_DEBUG,	"debug" },
  	{ EXC_PERF,	"performance monitoring" },
  	{ EXC_VEC,	"altivec unavailable" },
  	{ EXC_VSX,	"vsx unavailable" },
  	{ EXC_ITMISS,	"instruction tlb miss" },
  	{ EXC_DLMISS,	"data load tlb miss" },
  	{ EXC_DSMISS,	"data store tlb miss" },
  	{ EXC_BPT,	"instruction breakpoint" },
  	{ EXC_SMI,	"system management" },
  	{ EXC_VECAST_G4,	"altivec assist" },
  	{ EXC_THRM,	"thermal management" },
  	{ EXC_RUNMODETRC,	"run mode/trace" },
  	{ EXC_LAST,	NULL }
  };
  
  static const char *
  trapname(u_int vector)
  {
  	struct	powerpc_exception *pe;
  
  	for (pe = powerpc_exceptions; pe->vector != EXC_LAST; pe++) {
  		if (pe->vector == vector)
  			return (pe->name);
  	}
  
  	return ("unknown");
  }
  
  void
  trap(struct trapframe *frame)
  {
  	struct thread	*td;
  	struct proc	*p;
  #ifdef KDTRACE_HOOKS
  	uint32_t inst;
  #endif
  	int		sig, type, user;
  	u_int		ucode;
  	ksiginfo_t	ksi;
  
  	PCPU_INC(cnt.v_trap);
  
  	td = curthread;
  	p = td->td_proc;
  
  	type = ucode = frame->exc;
  	sig = 0;
  	user = frame->srr1 & PSL_PR;
  
  	CTR3(KTR_TRAP, "trap: %s type=%s (%s)", td->td_name,
  	    trapname(type), user ? "user" : "kernel");
  
  #ifdef KDTRACE_HOOKS
  	/*
  	 * A trap can occur while DTrace executes a probe. Before
  	 * executing the probe, DTrace blocks re-scheduling and sets
  	 * a flag in its per-cpu flags to indicate that it doesn't
  	 * want to fault. On returning from the probe, the no-fault
  	 * flag is cleared and finally re-scheduling is enabled.
  	 *
  	 * If the DTrace kernel module has registered a trap handler,
  	 * call it and if it returns non-zero, assume that it has
  	 * handled the trap and modified the trap frame so that this
  	 * function can return normally.
  	 */
  	if (dtrace_trap_func != NULL && (*dtrace_trap_func)(frame, type) != 0)
  		return;
  #endif
  
  	if (user) {
  		td->td_pticks = 0;
  		td->td_frame = frame;
  		if (td->td_cowgen != p->p_cowgen)
  			thread_cow_update(td);
  
  		/* User Mode Traps */
  		switch (type) {
  		case EXC_RUNMODETRC:
  		case EXC_TRC:
  			frame->srr1 &= ~PSL_SE;
  			sig = SIGTRAP;
  			ucode = TRAP_TRACE;
  			break;
  
  #ifdef __powerpc64__
  		case EXC_ISE:
  		case EXC_DSE:
  			if (handle_user_slb_spill(&p->p_vmspace->vm_pmap,
  			    (type == EXC_ISE) ? frame->srr0 : frame->dar) != 0){
  				sig = SIGSEGV;
  				ucode = SEGV_MAPERR;
  			}
  			break;
  #endif
  		case EXC_DSI:
  		case EXC_ISI:
  			sig = trap_pfault(frame, 1);
  			if (sig == SIGSEGV)
  				ucode = SEGV_MAPERR;
  			break;
  
  		case EXC_SC:
  			syscall(frame);
  			break;
  
  		case EXC_FPU:
  			KASSERT((td->td_pcb->pcb_flags & PCB_FPU) != PCB_FPU,
  			    ("FPU already enabled for thread"));
  			enable_fpu(td);
  			break;
  
  		case EXC_VEC:
  			KASSERT((td->td_pcb->pcb_flags & PCB_VEC) != PCB_VEC,
  			    ("Altivec already enabled for thread"));
  			enable_vec(td);
  			break;
  
  		case EXC_VSX:
  			KASSERT((td->td_pcb->pcb_flags & PCB_VSX) != PCB_VSX,
  			    ("VSX already enabled for thread"));
  			if (!(td->td_pcb->pcb_flags & PCB_VEC))
  				enable_vec(td);
  			if (!(td->td_pcb->pcb_flags & PCB_FPU))
  				save_fpu(td);
  			td->td_pcb->pcb_flags |= PCB_VSX;
  			enable_fpu(td);
  			break;
  
  		case EXC_VECAST_E:
  		case EXC_VECAST_G4:
  		case EXC_VECAST_G5:
  			/*
  			 * We get a VPU assist exception for IEEE mode
  			 * vector operations on denormalized floats.
  			 * Emulating this is a giant pain, so for now,
  			 * just switch off IEEE mode and treat them as
  			 * zero.
  			 */
  
  			save_vec(td);
  			td->td_pcb->pcb_vec.vscr |= ALTIVEC_VSCR_NJ;
  			enable_vec(td);
  			break;
  
  		case EXC_ALI:
  			if (fix_unaligned(td, frame) != 0) {
  				sig = SIGBUS;
  				ucode = BUS_ADRALN;
  			}
  			else
  				frame->srr0 += 4;
  			break;
  
  		case EXC_DEBUG:	/* Single stepping */
  			mtspr(SPR_DBSR, mfspr(SPR_DBSR));
  			frame->srr1 &= ~PSL_DE;
  			frame->cpu.booke.dbcr0 &= ~(DBCR0_IDM || DBCR0_IC);
  			sig = SIGTRAP;
  			ucode = TRAP_TRACE;
  			break;
  
  		case EXC_PGM:
  			/* Identify the trap reason */
  #ifdef AIM
  			if (frame->srr1 & EXC_PGM_TRAP) {
  #else
  			if (frame->cpu.booke.esr & ESR_PTR) {
  #endif
  #ifdef KDTRACE_HOOKS
  				inst = fuword32((const void *)frame->srr0);
  				if (inst == 0x0FFFDDDD &&
  				    dtrace_pid_probe_ptr != NULL) {
  					struct reg regs;
  					fill_regs(td, &regs);
  					(*dtrace_pid_probe_ptr)(&regs);
  					break;
  				}
  #endif
   				sig = SIGTRAP;
  				ucode = TRAP_BRKPT;
  			} else {
  				sig = ppc_instr_emulate(frame, td->td_pcb);
  				if (sig == SIGILL) {
  					if (frame->srr1 & EXC_PGM_PRIV)
  						ucode = ILL_PRVOPC;
  					else if (frame->srr1 & EXC_PGM_ILLEGAL)
  						ucode = ILL_ILLOPC;
  				} else if (sig == SIGFPE)
  					ucode = FPE_FLTINV;	/* Punt for now, invalid operation. */
  			}
  			break;
  
  		case EXC_MCHK:
  			/*
  			 * Note that this may not be recoverable for the user
  			 * process, depending on the type of machine check,
  			 * but it at least prevents the kernel from dying.
  			 */
  			sig = SIGBUS;
  			ucode = BUS_OBJERR;
  			break;
  
  		default:
  			trap_fatal(frame);
  		}
  	} else {
  		/* Kernel Mode Traps */
  
  		KASSERT(cold || td->td_ucred != NULL,
  		    ("kernel trap doesn't have ucred"));
  		switch (type) {
  #ifdef KDTRACE_HOOKS
  		case EXC_PGM:
  			if (frame->srr1 & EXC_PGM_TRAP) {
  				if (*(uint32_t *)frame->srr0 == EXC_DTRACE) {
  					if (dtrace_invop_jump_addr != NULL) {
  						dtrace_invop_jump_addr(frame);
  						return;
  					}
  				}
  			}
  			break;
  #endif
  #ifdef __powerpc64__
  		case EXC_DSE:
  			if ((frame->dar & SEGMENT_MASK) == USER_ADDR) {
  				__asm __volatile ("slbmte %0, %1" ::
  					"r"(td->td_pcb->pcb_cpu.aim.usr_vsid),
  					"r"(USER_SLB_SLBE));
  				return;
  			}
  			break;
  #endif
  		case EXC_DSI:
  			if (trap_pfault(frame, 0) == 0)
   				return;
  			break;
  		case EXC_MCHK:
  			if (handle_onfault(frame))
   				return;
  			break;
  		default:
  			break;
  		}
  		trap_fatal(frame);
  	}
  
  	if (sig != 0) {
  		if (p->p_sysent->sv_transtrap != NULL)
  			sig = (p->p_sysent->sv_transtrap)(sig, type);
  		ksiginfo_init_trap(&ksi);
  		ksi.ksi_signo = sig;
  		ksi.ksi_code = (int) ucode; /* XXX, not POSIX */
  		/* ksi.ksi_addr = ? */
  		ksi.ksi_trapno = type;
  		trapsignal(td, &ksi);
  	}
  
  	userret(td, frame);
  }
  
  static void
  trap_fatal(struct trapframe *frame)
  {
  
  	printtrap(frame->exc, frame, 1, (frame->srr1 & PSL_PR));
  #ifdef KDB
  	if ((debugger_on_panic || kdb_active) &&
  	    kdb_trap(frame->exc, 0, frame))
  		return;
  #endif
  	panic("%s trap", trapname(frame->exc));
  }
  
  static void
  printtrap(u_int vector, struct trapframe *frame, int isfatal, int user)
  {
  	uint16_t ver;
  #ifdef BOOKE
  	vm_paddr_t pa;
  #endif
  
  	printf("\n");
  	printf("%s %s trap:\n", isfatal ? "fatal" : "handled",
  	    user ? "user" : "kernel");
  	printf("\n");
  	printf("   exception       = 0x%x (%s)\n", vector, trapname(vector));
  	switch (vector) {
  	case EXC_DSE:
  	case EXC_DSI:
  	case EXC_DTMISS:
  		printf("   virtual address = 0x%" PRIxPTR "\n", frame->dar);
  #ifdef AIM
  		printf("   dsisr           = 0x%lx\n",
  		    (u_long)frame->cpu.aim.dsisr);
  #endif
  		break;
  	case EXC_ISE:
  	case EXC_ISI:
  	case EXC_ITMISS:
  		printf("   virtual address = 0x%" PRIxPTR "\n", frame->srr0);
  		break;
  	case EXC_MCHK:
  		ver = mfpvr() >> 16;
  #if defined(AIM)
  		if (MPC745X_P(ver))
  			printf("    msssr0         = 0x%lx\n",
  			    (u_long)mfspr(SPR_MSSSR0));
  #elif defined(BOOKE)
  		pa = mfspr(SPR_MCARU);
  		pa = (pa << 32) | (u_register_t)mfspr(SPR_MCAR);
  		printf("   mcsr            = 0x%lx\n", (u_long)mfspr(SPR_MCSR));
  		printf("   mcar            = 0x%jx\n", (uintmax_t)pa);
  #endif
  		break;
  	}
  #ifdef BOOKE
  	printf("   esr             = 0x%" PRIxPTR "\n",
  	    frame->cpu.booke.esr);
  #endif
  	printf("   srr0            = 0x%" PRIxPTR "\n", frame->srr0);
  	printf("   srr1            = 0x%lx\n", (u_long)frame->srr1);
  	printf("   lr              = 0x%" PRIxPTR "\n", frame->lr);
  	printf("   curthread       = %p\n", curthread);
  	if (curthread != NULL)
  		printf("          pid = %d, comm = %s\n",
  		    curthread->td_proc->p_pid, curthread->td_name);
  	printf("\n");
  }
  
  /*
   * Handles a fatal fault when we have onfault state to recover.  Returns
   * non-zero if there was onfault recovery state available.
   */
  static int
  handle_onfault(struct trapframe *frame)
  {
  	struct		thread *td;
  	jmp_buf		*fb;
  
  	td = curthread;
  	fb = td->td_pcb->pcb_onfault;
  	if (fb != NULL) {
  		frame->srr0 = (*fb)->_jb[FAULTBUF_LR];
  		frame->fixreg[1] = (*fb)->_jb[FAULTBUF_R1];
  		frame->fixreg[2] = (*fb)->_jb[FAULTBUF_R2];
  		frame->fixreg[3] = 1;
  		frame->cr = (*fb)->_jb[FAULTBUF_CR];
  		bcopy(&(*fb)->_jb[FAULTBUF_R14], &frame->fixreg[14],
  		    18 * sizeof(register_t));
  		td->td_pcb->pcb_onfault = NULL; /* Returns twice, not thrice */
  		return (1);
  	}
  	return (0);
  }
  
  int
  cpu_fetch_syscall_args(struct thread *td, struct syscall_args *sa)
  {
  	struct proc *p;
  	struct trapframe *frame;
  	caddr_t	params;
  	size_t argsz;
  	int error, n, i;
  
  	p = td->td_proc;
  	frame = td->td_frame;
  
  	sa->code = frame->fixreg[0];
  	params = (caddr_t)(frame->fixreg + FIRSTARG);
  	n = NARGREG;
  
  	if (sa->code == SYS_syscall) {
  		/*
  		 * code is first argument,
  		 * followed by actual args.
  		 */
  		sa->code = *(register_t *) params;
  		params += sizeof(register_t);
  		n -= 1;
  	} else if (sa->code == SYS___syscall) {
  		/*
  		 * Like syscall, but code is a quad,
  		 * so as to maintain quad alignment
  		 * for the rest of the args.
  		 */
  		if (SV_PROC_FLAG(p, SV_ILP32)) {
  			params += sizeof(register_t);
  			sa->code = *(register_t *) params;
  			params += sizeof(register_t);
  			n -= 2;
  		} else {
  			sa->code = *(register_t *) params;
  			params += sizeof(register_t);
  			n -= 1;
  		}
  	}
  
   	if (p->p_sysent->sv_mask)
  		sa->code &= p->p_sysent->sv_mask;
  	if (sa->code >= p->p_sysent->sv_size)
  		sa->callp = &p->p_sysent->sv_table[0];
  	else
  		sa->callp = &p->p_sysent->sv_table[sa->code];
  
  	sa->narg = sa->callp->sy_narg;
  
  	if (SV_PROC_FLAG(p, SV_ILP32)) {
  		argsz = sizeof(uint32_t);
  
  		for (i = 0; i < n; i++)
  			sa->args[i] = ((u_register_t *)(params))[i] &
  			    0xffffffff;
  	} else {
  		argsz = sizeof(uint64_t);
  
  		for (i = 0; i < n; i++)
  			sa->args[i] = ((u_register_t *)(params))[i];
  	}
  
  	if (sa->narg > n)
  		error = copyin(MOREARGS(frame->fixreg[1]), sa->args + n,
  			       (sa->narg - n) * argsz);
  	else
  		error = 0;
  
  #ifdef __powerpc64__
  	if (SV_PROC_FLAG(p, SV_ILP32) && sa->narg > n) {
  		/* Expand the size of arguments copied from the stack */
  
  		for (i = sa->narg; i >= n; i--)
  			sa->args[i] = ((uint32_t *)(&sa->args[n]))[i-n];
  	}
  #endif
  
  	if (error == 0) {
  		td->td_retval[0] = 0;
  		td->td_retval[1] = frame->fixreg[FIRSTARG + 1];
  	}
  	return (error);
  }
  
  #include "../../kern/subr_syscall.c"
  
  void
  syscall(struct trapframe *frame)
  {
  	struct thread *td;
  	struct syscall_args sa;
  	int error;
  
  	td = curthread;
  	td->td_frame = frame;
  
  #ifdef __powerpc64__
  	/*
  	 * Speculatively restore last user SLB segment, which we know is
  	 * invalid already, since we are likely to do copyin()/copyout().
  	 */
  	__asm __volatile ("slbmte %0, %1; isync" ::
              "r"(td->td_pcb->pcb_cpu.aim.usr_vsid), "r"(USER_SLB_SLBE));
  #endif
  
  	error = syscallenter(td, &sa);
  	syscallret(td, error, &sa);
  }
  
  #ifdef __powerpc64__
  /* Handle kernel SLB faults -- runs in real mode, all seat belts off */
  void
  handle_kernel_slb_spill(int type, register_t dar, register_t srr0)
  {
  	struct slb *slbcache;
  	uint64_t slbe, slbv;
  	uint64_t esid, addr;
  	int i;
  
  	addr = (type == EXC_ISE) ? srr0 : dar;
  	slbcache = PCPU_GET(slb);
  	esid = (uintptr_t)addr >> ADDR_SR_SHFT;
  	slbe = (esid << SLBE_ESID_SHIFT) | SLBE_VALID;
  	
  	/* See if the hardware flushed this somehow (can happen in LPARs) */
  	for (i = 0; i < n_slbs; i++)
  		if (slbcache[i].slbe == (slbe | (uint64_t)i))
  			return;
  
  	/* Not in the map, needs to actually be added */
  	slbv = kernel_va_to_slbv(addr);
  	if (slbcache[USER_SLB_SLOT].slbe == 0) {
  		for (i = 0; i < n_slbs; i++) {
  			if (i == USER_SLB_SLOT)
  				continue;
  			if (!(slbcache[i].slbe & SLBE_VALID))
  				goto fillkernslb;
  		}
  
  		if (i == n_slbs)
  			slbcache[USER_SLB_SLOT].slbe = 1;
  	}
  
  	/* Sacrifice a random SLB entry that is not the user entry */
  	i = mftb() % n_slbs;
  	if (i == USER_SLB_SLOT)
  		i = (i+1) % n_slbs;
  
  fillkernslb:
  	/* Write new entry */
  	slbcache[i].slbv = slbv;
  	slbcache[i].slbe = slbe | (uint64_t)i;
  
  	/* Trap handler will restore from cache on exit */
  }
  
  static int 
  handle_user_slb_spill(pmap_t pm, vm_offset_t addr)
  {
  	struct slb *user_entry;
  	uint64_t esid;
  	int i;
  
  	esid = (uintptr_t)addr >> ADDR_SR_SHFT;
  
  	PMAP_LOCK(pm);
  	user_entry = user_va_to_slb_entry(pm, addr);
  
  	if (user_entry == NULL) {
  		/* allocate_vsid auto-spills it */
  		(void)allocate_user_vsid(pm, esid, 0);
  	} else {
  		/*
  		 * Check that another CPU has not already mapped this.
  		 * XXX: Per-thread SLB caches would be better.
  		 */
  		for (i = 0; i < pm->pm_slb_len; i++)
  			if (pm->pm_slb[i] == user_entry)
  				break;
  
  		if (i == pm->pm_slb_len)
  			slb_insert_user(pm, user_entry);
  	}
  	PMAP_UNLOCK(pm);
  
  	return (0);
  }
  #endif
  
  static int
  trap_pfault(struct trapframe *frame, int user)
  {
  	vm_offset_t	eva, va;
  	struct		thread *td;
  	struct		proc *p;
  	vm_map_t	map;
  	vm_prot_t	ftype;
  	int		rv;
  #ifdef AIM
  	register_t	user_sr;
  #endif
  
  	td = curthread;
  	p = td->td_proc;
  	if (frame->exc == EXC_ISI) {
  		eva = frame->srr0;
  		ftype = VM_PROT_EXECUTE;
  		if (frame->srr1 & SRR1_ISI_PFAULT)
  			ftype |= VM_PROT_READ;
  	} else {
  		eva = frame->dar;
  #ifdef BOOKE
  		if (frame->cpu.booke.esr & ESR_ST)
  #else
  		if (frame->cpu.aim.dsisr & DSISR_STORE)
  #endif
  			ftype = VM_PROT_WRITE;
  		else
  			ftype = VM_PROT_READ;
  	}
  
  	if (user) {
  		KASSERT(p->p_vmspace != NULL, ("trap_pfault: vmspace  NULL"));
  		map = &p->p_vmspace->vm_map;
  	} else {
  #ifdef BOOKE
  		if (eva < VM_MAXUSER_ADDRESS) {
  #else
  		if ((eva >> ADDR_SR_SHFT) == (USER_ADDR >> ADDR_SR_SHFT)) {
  #endif
  			map = &p->p_vmspace->vm_map;
  
  #ifdef AIM
  			user_sr = td->td_pcb->pcb_cpu.aim.usr_segm;
  			eva &= ADDR_PIDX | ADDR_POFF;
  			eva |= user_sr << ADDR_SR_SHFT;
  #endif
  		} else {
  			map = kernel_map;
  		}
  	}
  	va = trunc_page(eva);
  
  	/* Fault in the page. */
  	rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL);
  	/*
  	 * XXXDTRACE: add dtrace_doubletrap_func here?
  	 */
  
  	if (rv == KERN_SUCCESS)
  		return (0);
  
  	if (!user && handle_onfault(frame))
  		return (0);
  
  	return (SIGSEGV);
  }
  
  /*
   * For now, this only deals with the particular unaligned access case
   * that gcc tends to generate.  Eventually it should handle all of the
   * possibilities that can happen on a 32-bit PowerPC in big-endian mode.
   */
  
  static int
  fix_unaligned(struct thread *td, struct trapframe *frame)
  {
  	struct thread	*fputhread;
  	int		indicator, reg;
  	double		*fpr;
  
  	indicator = EXC_ALI_OPCODE_INDICATOR(frame->cpu.aim.dsisr);
  
  	switch (indicator) {
  	case EXC_ALI_LFD:
  	case EXC_ALI_STFD:
  		reg = EXC_ALI_RST(frame->cpu.aim.dsisr);
  		fpr = &td->td_pcb->pcb_fpu.fpr[reg].fpr;
  		fputhread = PCPU_GET(fputhread);
  
  		/* Juggle the FPU to ensure that we've initialized
  		 * the FPRs, and that their current state is in
  		 * the PCB.
  		 */
  		if (fputhread != td) {
  			if (fputhread)
  				save_fpu(fputhread);
  			enable_fpu(td);
  		}
  		save_fpu(td);
  
  		if (indicator == EXC_ALI_LFD) {
  			if (copyin((void *)frame->dar, fpr,
  			    sizeof(double)) != 0)
  				return (-1);
  			enable_fpu(td);
  		} else {
  			if (copyout(fpr, (void *)frame->dar,
  			    sizeof(double)) != 0)
  				return (-1);
  		}
  		return (0);
  		break;
  	}
  
  	return (-1);
  }
  
  #ifdef KDB
  int db_trap_glue(struct trapframe *);		/* Called from trap_subr.S */
  
  int
  db_trap_glue(struct trapframe *frame)
  {
  	if (!(frame->srr1 & PSL_PR)
  	    && (frame->exc == EXC_TRC || frame->exc == EXC_RUNMODETRC
  #ifdef AIM
  		|| (frame->exc == EXC_PGM
  		    && (frame->srr1 & EXC_PGM_TRAP))
  #else
  		|| (frame->exc == EXC_DEBUG)
  #endif
  		|| frame->exc == EXC_BPT
  		|| frame->exc == EXC_DSI)) {
  		int type = frame->exc;
  
  		/* Ignore DTrace traps. */
  		if (*(uint32_t *)frame->srr0 == EXC_DTRACE)
  			return (0);
  #ifdef AIM
  		if (type == EXC_PGM && (frame->srr1 & EXC_PGM_TRAP)) {
  #else
  		if (frame->cpu.booke.esr & ESR_PTR) {
  #endif
  			type = T_BREAKPOINT;
  		}
  		return (kdb_trap(type, 0, frame));
  	}
  
  	return (0);
  }
  #endif
  