xref: /src/sys/arch/powerpc/ibm4xx/trap.c

/*	$NetBSD: trap.c,v 1.102 2023/10/05 19:41:05 ad Exp $	*/

/*
 * Copyright 2001 Wasabi Systems, Inc.
 * All rights reserved.
 *
 * Written by Eduardo Horvath and Simon Burge for Wasabi Systems, Inc.
 *
 * 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 for the NetBSD Project by
 *      Wasabi Systems, Inc.
 * 4. The name of Wasabi Systems, Inc. may not be used to endorse
 *    or promote products derived from this software without specific prior
 *    written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``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 WASABI SYSTEMS, INC
 * 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.
 */

/*
 * 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.
 */

#define	__UFETCHSTORE_PRIVATE

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: trap.c,v 1.102 2023/10/05 19:41:05 ad Exp $");

#ifdef _KERNEL_OPT
#include "opt_ddb.h"
#include "opt_kgdb.h"
#include "opt_ppcarch.h"
#include "opt_ppcopts.h"
#endif

#include <sys/param.h>
#include <sys/cpu.h>
#include <sys/kauth.h>
#include <sys/proc.h>
#include <sys/ptrace.h>
#include <sys/reboot.h>
#include <sys/syscall.h>
#include <sys/systm.h>

#if defined(KGDB)
#include <sys/kgdb.h>
#endif

#include <uvm/uvm_extern.h>

#include <dev/cons.h>

#include <machine/fpu.h>
#include <machine/frame.h>
#include <machine/pcb.h>
#include <machine/psl.h>
#include <machine/trap.h>

#include <powerpc/db_machdep.h>
#include <powerpc/spr.h>
#include <powerpc/userret.h>

#include <powerpc/ibm4xx/cpu.h>
#include <powerpc/ibm4xx/pmap.h>
#include <powerpc/ibm4xx/spr.h>
#include <powerpc/ibm4xx/tlb.h>

#include <powerpc/fpu/fpu_extern.h>

/* These definitions should probably be somewhere else			XXX */
#define	FIRSTARG	3		/* first argument is in reg 3 */
#define	NARGREG		8		/* 8 args are in registers */
#define	MOREARGS(sp)	((void *)((int)(sp) + 8)) /* more args go here */

void trap(struct trapframe *);	/* Called from locore / trap_subr */
#if 0
/* Not currently used nor exposed externally in any header file */
int badaddr(void *, size_t);
int badaddr_read(void *, size_t, int *);
#endif
int ctx_setup(int, int);

#ifndef PPC_NO_UNALIGNED
static bool fix_unaligned(struct trapframe *, ksiginfo_t *);
#endif

#ifdef DEBUG
#define TDB_ALL	0x1
int trapdebug = /* TDB_ALL */ 0;
#define	DBPRINTF(x, y)	if (trapdebug & (x)) printf y
#else
#define DBPRINTF(x, y)
#endif

void
trap(struct trapframe *tf)
{
	struct lwp *l = curlwp;
	struct proc *p = l->l_proc;
	struct pcb *pcb;
	int type = tf->tf_exc;
	int ftype, rv;
	ksiginfo_t ksi;

	KASSERT(l->l_stat == LSONPROC);

	if (tf->tf_srr1 & PSL_PR) {
		type |= EXC_USER;
	}

	ftype = VM_PROT_READ;

	DBPRINTF(TDB_ALL, ("trap(%x) at %lx from frame %p &frame %p\n",
	    type, tf->tf_srr0, tf, &tf));

	switch (type) {
	case EXC_DEBUG|EXC_USER:
		/* We don't use hardware breakpoints for userland. */
		goto brain_damage;

	case EXC_TRC|EXC_USER:
		KSI_INIT_TRAP(&ksi);
		ksi.ksi_signo = SIGTRAP;
		ksi.ksi_trap = EXC_TRC;
		ksi.ksi_addr = (void *)tf->tf_srr0;
		trapsignal(l, &ksi);
		break;

	case EXC_DSI:
		/* FALLTHROUGH */
	case EXC_DTMISS:
		{
			struct vm_map *map;
			vaddr_t va;
			struct faultbuf *fb;

			pcb = lwp_getpcb(l);
			fb = pcb->pcb_onfault;

			if (curcpu()->ci_idepth >= 0) {
				rv = EFAULT;
				goto out;
			}

			va = tf->tf_dear;
			if (tf->tf_pid == KERNEL_PID) {
				map = kernel_map;
			} else {
				map = &p->p_vmspace->vm_map;
			}

			if (tf->tf_esr & (ESR_DST|ESR_DIZ))
				ftype = VM_PROT_WRITE;

			DBPRINTF(TDB_ALL,
			    ("trap(EXC_DSI) at %lx %s fault on %p esr %x\n",
			    tf->tf_srr0,
			    (ftype & VM_PROT_WRITE) ? "write" : "read",
			    (void *)va, tf->tf_esr));

			pcb->pcb_onfault = NULL;
			rv = uvm_fault(map, trunc_page(va), ftype);
			pcb->pcb_onfault = fb;
			if (rv == 0)
				return;
out:
			if (fb != NULL) {
				tf->tf_pid = KERNEL_PID;
				tf->tf_srr0 = fb->fb_pc;
				tf->tf_srr1 |= PSL_IR; /* Re-enable IMMU */
				tf->tf_cr = fb->fb_cr;
				tf->tf_fixreg[1] = fb->fb_sp;
				tf->tf_fixreg[2] = fb->fb_r2;
				tf->tf_fixreg[3] = rv;
				memcpy(&tf->tf_fixreg[13], fb->fb_fixreg,
				    sizeof(fb->fb_fixreg));
				return;
			}
		}
		goto brain_damage;

	case EXC_DSI|EXC_USER:
		/* FALLTHROUGH */
	case EXC_DTMISS|EXC_USER:
		if (tf->tf_esr & (ESR_DST|ESR_DIZ))
			ftype = VM_PROT_WRITE;

		DBPRINTF(TDB_ALL,
		    ("trap(EXC_DSI|EXC_USER) at %lx %s fault on %lx %x\n",
		    tf->tf_srr0, (ftype & VM_PROT_WRITE) ? "write" : "read",
		    tf->tf_dear, tf->tf_esr));
		KASSERT(l == curlwp && (l->l_stat == LSONPROC));
//		KASSERT(curpcb->pcb_onfault == NULL);
		rv = uvm_fault(&p->p_vmspace->vm_map, trunc_page(tf->tf_dear),
		    ftype);
		if (rv == 0) {
			break;
		}
		KSI_INIT_TRAP(&ksi);
		ksi.ksi_trap = EXC_DSI;
		ksi.ksi_addr = (void *)tf->tf_dear;
vm_signal:
		switch (rv) {
		case EINVAL:
			ksi.ksi_signo = SIGBUS;
			ksi.ksi_code = BUS_ADRERR;
			break;
		case EACCES:
			ksi.ksi_signo = SIGSEGV;
			ksi.ksi_code = SEGV_ACCERR;
			break;
		case ENOMEM:
			ksi.ksi_signo = SIGKILL;
			printf("UVM: pid %d.%d (%s), uid %d killed: "
			       "out of swap\n", p->p_pid, l->l_lid, p->p_comm,
			       l->l_cred ? kauth_cred_geteuid(l->l_cred) : -1);
			break;
		default:
			ksi.ksi_signo = SIGSEGV;
			ksi.ksi_code = SEGV_MAPERR;
			break;
		}
		trapsignal(l, &ksi);
		break;

	case EXC_ITMISS|EXC_USER:
	case EXC_ISI|EXC_USER:
		ftype = VM_PROT_EXECUTE;
		DBPRINTF(TDB_ALL,
		    ("trap(EXC_ISI|EXC_USER) at %lx execute fault tf %p\n",
		    tf->tf_srr0, tf));
//		KASSERT(curpcb->pcb_onfault == NULL);
		rv = uvm_fault(&p->p_vmspace->vm_map, trunc_page(tf->tf_srr0),
		    ftype);
		if (rv == 0) {
			break;
		}
isi:
		KSI_INIT_TRAP(&ksi);
		ksi.ksi_trap = EXC_ISI;
		ksi.ksi_addr = (void *)tf->tf_srr0;
		goto vm_signal;
		break;

	case EXC_AST|EXC_USER:
		cpu_ast(l, curcpu());
		break;

	case EXC_ALI|EXC_USER:
		if (fix_unaligned(tf, &ksi))
			trapsignal(l, &ksi);
		break;

	case EXC_PGM|EXC_USER:
		curcpu()->ci_data.cpu_ntrap++;

		KSI_INIT_TRAP(&ksi);
		ksi.ksi_trap = EXC_PGM;
		ksi.ksi_addr = (void *)tf->tf_srr0;

		if (tf->tf_esr & ESR_PTR) {
			vaddr_t va;
sigtrap:
			va = (vaddr_t)tf->tf_srr0;
			/*
		 	 * Restore original instruction and clear BP.
		 	 */
			if (p->p_md.md_ss_addr[0] == va ||
			    p->p_md.md_ss_addr[1] == va) {
				rv = ppc_sstep(l, 0);
				if (rv != 0)
					goto vm_signal;
				ksi.ksi_code = TRAP_TRACE;
			} else
				ksi.ksi_code = TRAP_BRKPT;
			if (p->p_raslist != NULL &&
			    ras_lookup(p, (void *)va) != (void *)-1) {
				tf->tf_srr0 += (ksi.ksi_code == TRAP_TRACE) ?
				    0 : 4;
				break;
			}
			ksi.ksi_signo = SIGTRAP;
		} else if (tf->tf_esr & ESR_PPR) {
			uint32_t opcode;

			rv = copyin((void *)tf->tf_srr0, &opcode,
			    sizeof(opcode));
			if (rv)
				goto isi;
			if (emulate_mxmsr(l, tf, opcode)) {
				tf->tf_srr0 += 4;
				break;
			}

			ksi.ksi_code = ILL_PRVOPC;
			ksi.ksi_signo = SIGILL;
		} else {
			pcb = lwp_getpcb(l);

			if (__predict_false(!fpu_used_p(l))) {
				memset(&pcb->pcb_fpu, 0, sizeof(pcb->pcb_fpu));
				fpu_mark_used(l);
			}

			if (fpu_emulate(tf, &pcb->pcb_fpu, &ksi)) {
				if (ksi.ksi_signo == 0)	/* was emulated */
					break;
				else if (ksi.ksi_signo == SIGTRAP)
					goto sigtrap;	/* XXX H/W bug? */
			} else {
				ksi.ksi_code = ILL_ILLOPC;
				ksi.ksi_signo = SIGILL;
			}
		}

		trapsignal(l, &ksi);
		break;

	case EXC_MCHK:
		{
			struct faultbuf *fb;

			pcb = lwp_getpcb(l);
			if ((fb = pcb->pcb_onfault) != NULL) {
				tf->tf_pid = KERNEL_PID;
				tf->tf_srr0 = fb->fb_pc;
				tf->tf_srr1 |= PSL_IR; /* Re-enable IMMU */
				tf->tf_fixreg[1] = fb->fb_sp;
				tf->tf_fixreg[2] = fb->fb_r2;
				tf->tf_fixreg[3] = 1; /* Return TRUE */
				tf->tf_cr = fb->fb_cr;
				memcpy(&tf->tf_fixreg[13], fb->fb_fixreg,
				    sizeof(fb->fb_fixreg));
				return;
			}
		}
		goto brain_damage;

	default:
brain_damage:
		printf("trap type 0x%x at 0x%lx\n", type, tf->tf_srr0);
#if defined(DDB) || defined(KGDB)
		if (kdb_trap(type, tf))
			return;
#endif
#ifdef TRAP_PANICWAIT
		printf("Press a key to panic.\n");
		cngetc();
#endif
		panic("trap");
	}

	/* Invoke powerpc userret code */
	userret(l, tf);
}

int
ctx_setup(int ctx, int srr1)
{
	volatile struct pmap *pm;

	/* Update PID if we're returning to user mode. */
	if (srr1 & PSL_PR) {
		pm = curproc->p_vmspace->vm_map.pmap;
		if (!pm->pm_ctx) {
			ctx_alloc(__UNVOLATILE(pm));
		}
		ctx = pm->pm_ctx;
	}
	else if (!ctx) {
		ctx = KERNEL_PID;
	}
	return (ctx);
}

/*
 * Used by copyin()/copyout()
 */
extern vaddr_t vmaprange(struct proc *, vaddr_t, vsize_t, int);
extern void vunmaprange(vaddr_t, vsize_t);
static int bigcopyin(const void *, void *, size_t );
static int bigcopyout(const void *, void *, size_t );

#ifdef __clang__
#pragma clang optimize off
#endif
int
copyin(const void *uaddr, void *kaddr, size_t len)
{
	struct pmap *pm = curproc->p_vmspace->vm_map.pmap;
	int rv, msr, pid, tmp, ctx;
	struct faultbuf env;

	/* For bigger buffers use the faster copy */
	if (len > 1024)
		return (bigcopyin(uaddr, kaddr, len));

	if ((rv = setfault(&env))) {
		curpcb->pcb_onfault = NULL;
		return rv;
	}

	if (!(ctx = pm->pm_ctx)) {
		/* No context -- assign it one */
		ctx_alloc(pm);
		ctx = pm->pm_ctx;
	}

	__asm volatile (
		"mfmsr	%[msr];"		/* Save MSR */
		"li	%[tmp],0x20;"		/* Disable IMMU */
		"andc	%[tmp],%[msr],%[tmp];"
		"mtmsr	%[tmp];"
		"isync;"
		MFPID(%[pid])			/* Save old PID */

		"srwi.	%[tmp],%[len],0x2;"	/* How many words? */
		"beq-	2f;"			/* No words. Go do bytes */
		"mtctr	%[tmp];"

	"1:"	MTPID(%[ctx])
		"isync;"
#ifdef PPC_IBM403
		"lswi	%[tmp],%[uaddr],4;"	/* Load user word */
#else
		"lwz	%[tmp],0(%[uaddr]);"
#endif
		"addi	%[uaddr],%[uaddr],0x4;"	/* next uaddr word */
		"sync;"

		MTPID(%[pid])
		"isync;"
#ifdef PPC_IBM403
		"stswi	%[tmp],%[kaddr],4;"	/* Store kernel word */
#else
		"stw	%[tmp],0(%[kaddr]);"
#endif
		"addi	%[kaddr],%[kaddr],0x4;"	/* next kaddr word */
		"sync;"
		"bdnz	1b;"			/* repeat */

	"2:"	"andi.	%[tmp],%[len],0x3;"	/* How many remaining bytes? */
		"beq	10f;"
		"mtxer	%[tmp];"

		MTPID(%[ctx])
		"isync;"
		"lswx	%[tmp],0,%[uaddr];"	/* Load user bytes */
		"sync;"

		MTPID(%[pid])
		"isync;"
		"stswx	%[tmp],0,%[kaddr];"	/* Store kernel bytes */
		"sync;"

	"10:"	"mtmsr	%[msr];"		/* Restore MSR */
		"isync;"

		: [msr] "=&r" (msr), [pid] "=&r" (pid), [tmp] "=&r" (tmp)
		: [uaddr] "b" (uaddr), [kaddr] "b" (kaddr),
		  [ctx] "r" (ctx), [len] "r" (len)
		: "cr0", "ctr", "xer");

	curpcb->pcb_onfault = NULL;
	return 0;
}
#ifdef __clang__
#pragma clang optimize on
#endif

static int
bigcopyin(const void *uaddr, void *kaddr, size_t len)
{
	const char *up;
	char *kp = kaddr;
	struct lwp *l = curlwp;
	struct proc *p;
	struct faultbuf env;
	int error;

	p = l->l_proc;

	/*
	 * Stolen from physio():
	 */
	error = uvm_vslock(p->p_vmspace, __UNCONST(uaddr), len, VM_PROT_READ);
	if (error) {
		return error;
	}
	up = (char *)vmaprange(p, (vaddr_t)uaddr, len, VM_PROT_READ);

	if ((error = setfault(&env)) == 0) {
		memcpy(kp, up, len);
	}

	curpcb->pcb_onfault = NULL;
	vunmaprange((vaddr_t)up, len);
	uvm_vsunlock(p->p_vmspace, __UNCONST(uaddr), len);

	return error;
}

#ifdef __clang__
#pragma clang optimize off
#endif
int
copyout(const void *kaddr, void *uaddr, size_t len)
{
	struct pmap *pm = curproc->p_vmspace->vm_map.pmap;
	int rv, msr, pid, tmp, ctx;
	struct faultbuf env;

	/* For big copies use more efficient routine */
	if (len > 1024)
		return (bigcopyout(kaddr, uaddr, len));

	if ((rv = setfault(&env))) {
		curpcb->pcb_onfault = NULL;
		return rv;
	}

	if (!(ctx = pm->pm_ctx)) {
		/* No context -- assign it one */
		ctx_alloc(pm);
		ctx = pm->pm_ctx;
	}

	__asm volatile (
		"mfmsr	%[msr];"		/* Save MSR */
		"li	%[tmp],0x20;"		/* Disable IMMU */
		"andc	%[tmp],%[msr],%[tmp];"
		"mtmsr	%[tmp];"
		"isync;"
		MFPID(%[pid])			/* Save old PID */

		"srwi.	%[tmp],%[len],0x2;"	/* How many words? */
		"beq-	2f;"			/* No words. Go do bytes */
		"mtctr	%[tmp];"

	"1:"
#ifdef PPC_IBM403
		"lswi	%[tmp],%[kaddr],4;"	/* Load kernel word */
#else
		"lwz	%[tmp],0(%[kaddr]);"
#endif
		"addi	%[kaddr],%[kaddr],0x4;"	/* next kaddr word */
		"sync;"

		MTPID(%[ctx])
		"isync;"
#ifdef PPC_IBM403
		"stswi	%[tmp],%[uaddr],4;"	/* Store user word */
#else
		"stw	%[tmp],0(%[uaddr]);"
#endif
		"addi	%[uaddr],%[uaddr],0x4;"	/* next uaddr word */
		"sync;"

		MTPID(%[pid])
		"isync;"
		"bdnz	1b;"			/* repeat */

	"2:"	"andi.	%[tmp],%[len],0x3;"	/* How many remaining bytes? */
		"beq	10f;"
		"mtxer	%[tmp];"

		"lswx	%[tmp],0,%[kaddr];"	/* Load kernel bytes */
		"sync;"

		MTPID(%[ctx])
		"isync;"
		"stswx	%[tmp],0,%[uaddr];"	/* Store user bytes */
		"sync;"

		MTPID(%[pid])			/* Restore PID and MSR */
	"10:"	"mtmsr	%[msr];"
		"isync;"

		: [msr] "=&r" (msr), [pid] "=&r" (pid), [tmp] "=&r" (tmp)
		: [uaddr] "b" (uaddr), [kaddr] "b" (kaddr),
		  [ctx] "r" (ctx), [len] "r" (len)
		: "cr0", "ctr", "xer");

	curpcb->pcb_onfault = NULL;
	return 0;
}
#ifdef __clang__
#pragma clang optimize on
#endif

static int
bigcopyout(const void *kaddr, void *uaddr, size_t len)
{
	char *up;
	const char *kp = (const char *)kaddr;
	struct lwp *l = curlwp;
	struct proc *p;
	struct faultbuf env;
	int error;

	p = l->l_proc;

	/*
	 * Stolen from physio():
	 */
	error = uvm_vslock(p->p_vmspace, uaddr, len, VM_PROT_WRITE);
	if (error) {
		return error;
	}
	up = (char *)vmaprange(p, (vaddr_t)uaddr, len,
	    VM_PROT_READ | VM_PROT_WRITE);

	if ((error = setfault(&env)) == 0) {
		memcpy(up, kp, len);
	}

	curpcb->pcb_onfault = NULL;
	vunmaprange((vaddr_t)up, len);
	uvm_vsunlock(p->p_vmspace, uaddr, len);

	return error;
}

/*
 * kcopy(const void *src, void *dst, size_t len);
 *
 * Copy len bytes from src to dst, aborting if we encounter a fatal
 * page fault.
 *
 * kcopy() _must_ save and restore the old fault handler since it is
 * called by uiomove(), which may be in the path of servicing a non-fatal
 * page fault.
 */
int
kcopy(const void *src, void *dst, size_t len)
{
	struct faultbuf env, *oldfault;
	int rv;

	oldfault = curpcb->pcb_onfault;
	if ((rv = setfault(&env))) {
		curpcb->pcb_onfault = oldfault;
		return rv;
	}

	memcpy(dst, src, len);

	curpcb->pcb_onfault = oldfault;
	return 0;
}

#if 0
int
badaddr(void *addr, size_t size)
{

	return badaddr_read(addr, size, NULL);
}

int
badaddr_read(void *addr, size_t size, int *rptr)
{
	struct faultbuf env;
	int x;

	/* Get rid of any stale machine checks that have been waiting.  */
	__asm volatile ("sync; isync");

	if (setfault(&env)) {
		curpcb->pcb_onfault = NULL;
		__asm volatile ("sync");
		return 1;
	}

	__asm volatile ("sync");

	switch (size) {
	case 1:
		x = *(volatile int8_t *)addr;
		break;
	case 2:
		x = *(volatile int16_t *)addr;
		break;
	case 4:
		x = *(volatile int32_t *)addr;
		break;
	default:
		panic("badaddr: invalid size (%d)", size);
	}

	/* Make sure we took the machine check, if we caused one. */
	__asm volatile ("sync; isync");

	curpcb->pcb_onfault = NULL;
	__asm volatile ("sync");	/* To be sure. */

	/* Use the value to avoid reorder. */
	if (rptr)
		*rptr = x;

	return 0;
}
#endif

#ifndef PPC_NO_UNALIGNED
static bool
fix_unaligned(struct trapframe *tf, ksiginfo_t *ksi)
{

	KSI_INIT_TRAP(ksi);
	ksi->ksi_signo = SIGBUS;
	ksi->ksi_trap = EXC_ALI;
	ksi->ksi_addr = (void *)tf->tf_dear;
	return true;
}
#endif

/*
 * XXX Extremely lame implementations of _ufetch_* / _ustore_*.  IBM 4xx
 * experts should make versions that are good.
 */

#define UFETCH(sz)							\
int									\
_ufetch_ ## sz(const uint ## sz ## _t *uaddr, uint ## sz ## _t *valp)	\
{									\
	return copyin(uaddr, valp, sizeof(*valp));			\
}

UFETCH(8)
UFETCH(16)
UFETCH(32)

#define USTORE(sz)							\
int									\
_ustore_ ## sz(uint ## sz ## _t *uaddr, uint ## sz ## _t val)		\
{									\
	return copyout(&val, uaddr, sizeof(val));			\
}

USTORE(8)
USTORE(16)
USTORE(32)