freebsd-skq/sys/powerpc/aim/machdep.c
2003-01-08 12:27:47 +00:00

831 lines
19 KiB
C

/*
* 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.
*/
/*
* Copyright (C) 2001 Benno Rice
* 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.
*
* THIS SOFTWARE IS PROVIDED BY Benno Rice ``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: machdep.c,v 1.74.2.1 2000/11/01 16:13:48 tv Exp $
*/
#ifndef lint
static const char rcsid[] =
"$FreeBSD$";
#endif /* not lint */
#include "opt_ddb.h"
#include "opt_compat.h"
#include "opt_msgbuf.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/eventhandler.h>
#include <sys/imgact.h>
#include <sys/sysproto.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/ktr.h>
#include <sys/signalvar.h>
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/malloc.h>
#include <sys/reboot.h>
#include <sys/bio.h>
#include <sys/buf.h>
#include <sys/bus.h>
#include <sys/mbuf.h>
#include <sys/vmmeter.h>
#include <sys/msgbuf.h>
#include <sys/exec.h>
#include <sys/sysctl.h>
#include <sys/uio.h>
#include <sys/linker.h>
#include <sys/cons.h>
#include <sys/ucontext.h>
#include <sys/sysent.h>
#include <net/netisr.h>
#include <vm/vm.h>
#include <vm/vm_kern.h>
#include <vm/vm_page.h>
#include <vm/vm_map.h>
#include <vm/vm_extern.h>
#include <vm/vm_object.h>
#include <vm/vm_pager.h>
#include <sys/user.h>
#include <sys/ptrace.h>
#include <machine/bat.h>
#include <machine/clock.h>
#include <machine/md_var.h>
#include <machine/metadata.h>
#include <machine/reg.h>
#include <machine/fpu.h>
#include <machine/vmparam.h>
#include <machine/elf.h>
#include <machine/trap.h>
#include <machine/powerpc.h>
#include <dev/ofw/openfirm.h>
#include <ddb/ddb.h>
#include <sys/vnode.h>
#include <machine/sigframe.h>
int cold = 1;
char pcpu0[PAGE_SIZE];
char uarea0[UAREA_PAGES * PAGE_SIZE];
struct trapframe frame0;
vm_offset_t kstack0;
vm_offset_t kstack0_phys;
char machine[] = "powerpc";
SYSCTL_STRING(_hw, HW_MACHINE, machine, CTLFLAG_RD, machine, 0, "");
static char model[128];
SYSCTL_STRING(_hw, HW_MODEL, model, CTLFLAG_RD, model, 0, "");
static int cacheline_size = CACHELINESIZE;
SYSCTL_INT(_machdep, CPU_CACHELINE, cacheline_size,
CTLFLAG_RD, &cacheline_size, 0, "");
char bootpath[256];
#ifdef DDB
/* start and end of kernel symbol table */
void *ksym_start, *ksym_end;
#endif /* DDB */
static void cpu_startup(void *);
SYSINIT(cpu, SI_SUB_CPU, SI_ORDER_FIRST, cpu_startup, NULL)
void powerpc_init(u_int, u_int, u_int, void *);
int save_ofw_mapping(void);
int restore_ofw_mapping(void);
void install_extint(void (*)(void));
int setfault(faultbuf); /* defined in locore.S */
long Maxmem = 0;
static int chosen;
struct pmap ofw_pmap;
extern int ofmsr;
struct bat battable[16];
static void identifycpu(void);
struct kva_md_info kmi;
static void
powerpc_ofw_shutdown(void *junk, int howto)
{
if (howto & RB_HALT) {
OF_exit();
}
}
static void
cpu_startup(void *dummy)
{
/*
* Good {morning,afternoon,evening,night}.
*/
identifycpu();
/* startrtclock(); */
#ifdef PERFMON
perfmon_init();
#endif
printf("real memory = %ld (%ld MB)\n", ptoa(Maxmem),
ptoa(Maxmem) / 1048576);
/*
* Display any holes after the first chunk of extended memory.
*/
if (bootverbose) {
int indx;
printf("Physical memory chunk(s):\n");
for (indx = 0; phys_avail[indx + 1] != 0; indx += 2) {
int size1 = phys_avail[indx + 1] - phys_avail[indx];
printf("0x%08x - 0x%08x, %d bytes (%d pages)\n",
phys_avail[indx], phys_avail[indx + 1] - 1, size1,
size1 / PAGE_SIZE);
}
}
vm_ksubmap_init(&kmi);
printf("avail memory = %ld (%ld MB)\n", ptoa(cnt.v_free_count),
ptoa(cnt.v_free_count) / 1048576);
/*
* Set up buffers, so they can be used to read disk labels.
*/
bufinit();
vm_pager_bufferinit();
EVENTHANDLER_REGISTER(shutdown_final, powerpc_ofw_shutdown, 0,
SHUTDOWN_PRI_LAST);
#ifdef SMP
/*
* OK, enough kmem_alloc/malloc state should be up, lets get on with it!
*/
mp_start(); /* fire up the secondaries */
mp_announce();
#endif /* SMP */
}
void
identifycpu()
{
unsigned int pvr, version, revision;
/*
* Find cpu type (Do it by OpenFirmware?)
*/
__asm ("mfpvr %0" : "=r"(pvr));
version = pvr >> 16;
revision = pvr & 0xffff;
switch (version) {
case 0x0000:
sprintf(model, "Simulator (psim)");
break;
case 0x0001:
sprintf(model, "601");
break;
case 0x0003:
sprintf(model, "603 (Wart)");
break;
case 0x0004:
sprintf(model, "604 (Zephyr)");
break;
case 0x0005:
sprintf(model, "602 (Galahad)");
break;
case 0x0006:
sprintf(model, "603e (Stretch)");
break;
case 0x0007:
if ((revision && 0xf000) == 0x0000)
sprintf(model, "603ev (Valiant)");
else
sprintf(model, "603r (Goldeneye)");
break;
case 0x0008:
if ((revision && 0xf000) == 0x0000)
sprintf(model, "G3 / 750 (Arthur)");
else
sprintf(model, "G3 / 755 (Goldfinger)");
break;
case 0x0009:
if ((revision && 0xf000) == 0x0000)
sprintf(model, "604e (Sirocco)");
else
sprintf(model, "604r (Mach V)");
break;
case 0x000a:
sprintf(model, "604r (Mach V)");
break;
case 0x000c:
sprintf(model, "G4 / 7400 (Max)");
break;
case 0x0014:
sprintf(model, "620 (Red October)");
break;
case 0x0081:
sprintf(model, "8240 (Kahlua)");
break;
case 0x8000:
sprintf(model, "G4 / 7450 (V'ger)");
break;
case 0x800c:
sprintf(model, "G4 / 7410 (Nitro)");
break;
case 0x8081:
sprintf(model, "8245 (Kahlua II)");
break;
default:
sprintf(model, "Version %x", version);
break;
}
sprintf(model + strlen(model), " (Revision %x)", revision);
printf("CPU: PowerPC %s\n", model);
}
extern char kernel_text[], _end[];
extern void *trapcode, *trapsize;
extern void *alitrap, *alisize;
extern void *dsitrap, *dsisize;
extern void *isitrap, *isisize;
extern void *decrint, *decrsize;
extern void *tlbimiss, *tlbimsize;
extern void *tlbdlmiss, *tlbdlmsize;
extern void *tlbdsmiss, *tlbdsmsize;
extern void *extint, *extsize;
#if 0 /* XXX: interrupt handler. We'll get to this later */
extern void ext_intr(void);
#endif
#ifdef DDB
extern ddblow, ddbsize;
#endif
#ifdef IPKDB
extern ipkdblow, ipkdbsize;
#endif
void
powerpc_init(u_int startkernel, u_int endkernel, u_int basekernel, void *mdp)
{
struct pcpu *pc;
vm_offset_t end, off;
void *kmdp;
end = 0;
kmdp = NULL;
/*
* Parse metadata if present and fetch parameters. Must be done
* before console is inited so cninit gets the right value of
* boothowto.
*/
if (mdp != NULL) {
preload_metadata = mdp;
kmdp = preload_search_by_type("elf kernel");
if (kmdp != NULL) {
boothowto = MD_FETCH(kmdp, MODINFOMD_HOWTO, int);
kern_envp = MD_FETCH(kmdp, MODINFOMD_ENVP, char *);
end = MD_FETCH(kmdp, MODINFOMD_KERNEND, vm_offset_t);
}
}
/*
* Initialize the console before printing anything.
*/
cninit();
/*
* Complain if there is no metadata.
*/
if (mdp == NULL || kmdp == NULL) {
printf("powerpc_init: no loader metadata.\n");
}
#ifdef DDB
kdb_init();
#endif
/*
* XXX: Initialize the interrupt tables.
*/
bcopy(&dsitrap, (void *)EXC_DSI, (size_t)&dsisize);
bcopy(&isitrap, (void *)EXC_ISI, (size_t)&isisize);
bcopy(&trapcode, (void *)EXC_EXI, (size_t)&trapsize);
bcopy(&trapcode, (void *)EXC_ALI, (size_t)&trapsize);
bcopy(&trapcode, (void *)EXC_PGM, (size_t)&trapsize);
bcopy(&trapcode, (void *)EXC_FPU, (size_t)&trapsize);
bcopy(&trapcode, (void *)EXC_DECR, (size_t)&trapsize);
bcopy(&trapcode, (void *)EXC_SC, (size_t)&trapsize);
bcopy(&trapcode, (void *)EXC_TRC, (size_t)&trapsize);
__syncicache(EXC_RSVD, EXC_LAST - EXC_RSVD);
/*
* Start initializing proc0 and thread0.
*/
proc_linkup(&proc0, &ksegrp0, &kse0, &thread0);
proc0.p_uarea = (struct user *)uarea0;
proc0.p_stats = &proc0.p_uarea->u_stats;
thread0.td_frame = &frame0;
/*
* Set up per-cpu data.
*/
pc = (struct pcpu *)(pcpu0 + PAGE_SIZE) - 1;
pcpu_init(pc, 0, sizeof(struct pcpu));
pc->pc_curthread = &thread0;
pc->pc_curpcb = thread0.td_pcb;
pc->pc_cpuid = 0;
/* pc->pc_mid = mid; */
__asm __volatile("mtsprg 0, %0" :: "r"(pc));
mutex_init();
/*
* Make sure translation has been enabled
*/
mtmsr(mfmsr() | PSL_IR|PSL_DR|PSL_ME|PSL_RI);
/*
* Initialise virtual memory.
*/
pmap_bootstrap(startkernel, endkernel);
/*
* Initialize tunables.
*/
init_param1();
init_param2(physmem);
/*
* Finish setting up thread0.
*/
thread0.td_kstack = kstack0;
thread0.td_pcb = (struct pcb *)
(thread0.td_kstack + KSTACK_PAGES * PAGE_SIZE) - 1;
/*
* Map and initialise the message buffer.
*/
for (off = 0; off < round_page(MSGBUF_SIZE); off += PAGE_SIZE)
pmap_kenter((vm_offset_t)msgbufp + off, msgbuf_phys + off);
msgbufinit(msgbufp, MSGBUF_SIZE);
}
void
bzero(void *buf, size_t len)
{
caddr_t p;
p = buf;
while (((vm_offset_t) p & (sizeof(u_long) - 1)) && len) {
*p++ = 0;
len--;
}
while (len >= sizeof(u_long) * 8) {
*(u_long*) p = 0;
*((u_long*) p + 1) = 0;
*((u_long*) p + 2) = 0;
*((u_long*) p + 3) = 0;
len -= sizeof(u_long) * 8;
*((u_long*) p + 4) = 0;
*((u_long*) p + 5) = 0;
*((u_long*) p + 6) = 0;
*((u_long*) p + 7) = 0;
p += sizeof(u_long) * 8;
}
while (len >= sizeof(u_long)) {
*(u_long*) p = 0;
len -= sizeof(u_long);
p += sizeof(u_long);
}
while (len) {
*p++ = 0;
len--;
}
}
void
sendsig(sig_t catcher, int sig, sigset_t *mask, u_long code)
{
struct trapframe *tf;
struct sigframe *sfp;
struct sigacts *psp;
struct sigframe sf;
struct thread *td;
struct proc *p;
int oonstack, rndfsize;
td = curthread;
p = td->td_proc;
psp = p->p_sigacts;
tf = td->td_frame;
oonstack = sigonstack(tf->fixreg[1]);
rndfsize = ((sizeof(sf) + 15) / 16) * 16;
CTR4(KTR_SIG, "sendsig: td=%p (%s) catcher=%p sig=%d", td, p->p_comm,
catcher, sig);
/*
* Save user context
*/
memset(&sf, 0, sizeof(sf));
sf.sf_uc.uc_sigmask = *mask;
sf.sf_uc.uc_stack = p->p_sigstk;
sf.sf_uc.uc_stack.ss_flags = (p->p_flag & P_ALTSTACK)
? ((oonstack) ? SS_ONSTACK : 0) : SS_DISABLE;
sf.sf_uc.uc_mcontext.mc_onstack = (oonstack) ? 1 : 0;
memcpy(&sf.sf_uc.uc_mcontext.mc_frame, tf, sizeof(struct trapframe));
/*
* Allocate and validate space for the signal handler context.
*/
if ((p->p_flag & P_ALTSTACK) != 0 && !oonstack &&
SIGISMEMBER(psp->ps_sigonstack, sig)) {
sfp = (struct sigframe *)((caddr_t)p->p_sigstk.ss_sp +
p->p_sigstk.ss_size - rndfsize);
} else {
sfp = (struct sigframe *)(tf->fixreg[1] - rndfsize);
}
PROC_UNLOCK(p);
/*
* Translate the signal if appropriate (Linux emu ?)
*/
if (p->p_sysent->sv_sigtbl && sig <= p->p_sysent->sv_sigsize)
sig = p->p_sysent->sv_sigtbl[_SIG_IDX(sig)];
/*
* Save the floating-point state, if necessary, then copy it.
*/
/* XXX */
/*
* Set up the registers to return to sigcode.
*
* r1/sp - sigframe ptr
* lr - sig function, dispatched to by blrl in trampoline
* r3 - sig number
* r4 - SIGINFO ? &siginfo : exception code
* r5 - user context
* srr0 - trampoline function addr
*/
tf->lr = (register_t)catcher;
tf->fixreg[1] = (register_t)sfp;
tf->fixreg[FIRSTARG] = sig;
tf->fixreg[FIRSTARG+2] = (register_t)&sfp->sf_uc;
PROC_LOCK(p);
if (SIGISMEMBER(p->p_sigacts->ps_siginfo, sig)) {
/*
* Signal handler installed with SA_SIGINFO.
*/
tf->fixreg[FIRSTARG+1] = (register_t)&sfp->sf_si;
/*
* Fill siginfo structure.
*/
sf.sf_si.si_signo = sig;
sf.sf_si.si_code = code;
sf.sf_si.si_addr = (void *)tf->srr0;
} else {
/* Old FreeBSD-style arguments. */
tf->fixreg[FIRSTARG+1] = code;
}
PROC_UNLOCK(p);
tf->srr0 = (register_t)(PS_STRINGS - *(p->p_sysent->sv_szsigcode));
/*
* copy the frame out to userland.
*/
if (copyout((caddr_t)&sf, (caddr_t)sfp, sizeof(sf)) != 0) {
/*
* Process has trashed its stack. Kill it.
*/
CTR2(KTR_SIG, "sendsig: sigexit td=%p sfp=%p", td, sfp);
PROC_LOCK(p);
sigexit(td, SIGILL);
}
CTR3(KTR_SIG, "sendsig: return td=%p pc=%#x sp=%#x", td,
tf->srr0, tf->fixreg[1]);
PROC_LOCK(p);
}
int
sigreturn(struct thread *td, struct sigreturn_args *uap)
{
struct trapframe *tf;
struct proc *p;
ucontext_t uc;
CTR2(KTR_SIG, "sigreturn: td=%p ucp=%p", td, uap->sigcntxp);
if (copyin(uap->sigcntxp, &uc, sizeof(uc)) != 0) {
CTR1(KTR_SIG, "sigreturn: efault td=%p", td);
return (EFAULT);
}
/*
* Don't let the user set privileged MSR bits
*/
tf = td->td_frame;
if ((uc.uc_mcontext.mc_frame.srr1 & PSL_USERSTATIC) !=
(tf->srr1 & PSL_USERSTATIC)) {
return (EINVAL);
}
/*
* Restore the user-supplied context
*/
memcpy(tf, &uc.uc_mcontext.mc_frame, sizeof(struct trapframe));
p = td->td_proc;
PROC_LOCK(p);
p->p_sigmask = uc.uc_sigmask;
SIG_CANTMASK(p->p_sigmask);
signotify(p);
PROC_UNLOCK(p);
/*
* Restore FP state
*/
/* XXX */
CTR3(KTR_SIG, "sigreturn: return td=%p pc=%#x sp=%#x",
td, tf->srr0, tf->fixreg[1]);
return (EJUSTRETURN);
}
#ifdef COMPAT_FREEBSD4
int
freebsd4_sigreturn(struct thread *td, struct freebsd4_sigreturn_args *uap)
{
return sigreturn(td, (struct sigreturn_args *)uap);
}
#endif
int
get_mcontext(struct thread *td, mcontext_t *mcp)
{
return (ENOSYS);
}
int
set_mcontext(struct thread *td, const mcontext_t *mcp)
{
return (ENOSYS);
}
void
cpu_boot(int howto)
{
}
/*
* Shutdown the CPU as much as possible.
*/
void
cpu_halt(void)
{
OF_exit();
}
/*
* Set set up registers on exec.
*/
void
exec_setregs(struct thread *td, u_long entry, u_long stack, u_long ps_strings)
{
struct trapframe *tf;
struct ps_strings arginfo;
tf = trapframe(td);
bzero(tf, sizeof *tf);
tf->fixreg[1] = -roundup(-stack + 8, 16);
/*
* XXX Machine-independent code has already copied arguments and
* XXX environment to userland. Get them back here.
*/
(void)copyin((char *)PS_STRINGS, &arginfo, sizeof(arginfo));
/*
* Set up arguments for _start():
* _start(argc, argv, envp, obj, cleanup, ps_strings);
*
* Notes:
* - obj and cleanup are the auxilliary and termination
* vectors. They are fixed up by ld.elf_so.
* - ps_strings is a NetBSD extention, and will be
* ignored by executables which are strictly
* compliant with the SVR4 ABI.
*
* XXX We have to set both regs and retval here due to different
* XXX calling convention in trap.c and init_main.c.
*/
/*
* XXX PG: these get overwritten in the syscall return code.
* execve() should return EJUSTRETURN, like it does on NetBSD.
* Emulate by setting the syscall return value cells. The
* registers still have to be set for init's fork trampoline.
*/
td->td_retval[0] = arginfo.ps_nargvstr;
td->td_retval[1] = (register_t)arginfo.ps_argvstr;
tf->fixreg[3] = arginfo.ps_nargvstr;
tf->fixreg[4] = (register_t)arginfo.ps_argvstr;
tf->fixreg[5] = (register_t)arginfo.ps_envstr;
tf->fixreg[6] = 0; /* auxillary vector */
tf->fixreg[7] = 0; /* termination vector */
tf->fixreg[8] = (register_t)PS_STRINGS; /* NetBSD extension */
tf->srr0 = entry;
tf->srr1 = PSL_MBO | PSL_USERSET | PSL_FE_DFLT;
td->td_pcb->pcb_flags = 0;
}
#if !defined(DDB)
void
Debugger(const char *msg)
{
printf("Debugger(\"%s\") called.\n", msg);
}
#endif /* !defined(DDB) */
/* XXX: dummy {fill,set}_[fp]regs */
int
fill_regs(struct thread *td, struct reg *regs)
{
return (ENOSYS);
}
int
fill_dbregs(struct thread *td, struct dbreg *dbregs)
{
return (ENOSYS);
}
int
fill_fpregs(struct thread *td, struct fpreg *fpregs)
{
return (ENOSYS);
}
int
set_regs(struct thread *td, struct reg *regs)
{
return (ENOSYS);
}
int
set_dbregs(struct thread *td, struct dbreg *dbregs)
{
return (ENOSYS);
}
int
set_fpregs(struct thread *td, struct fpreg *fpregs)
{
return (ENOSYS);
}
int
ptrace_set_pc(struct thread *td, unsigned long addr)
{
/* XXX: coming soon... */
return (ENOSYS);
}
int
ptrace_single_step(struct thread *td)
{
/* XXX: coming soon... */
return (ENOSYS);
}
/*
* Initialise a struct pcpu.
*/
void
cpu_pcpu_init(struct pcpu *pcpu, int cpuid, size_t sz)
{
pcpu->pc_current_asngen = 1;
}
/*
* 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 thread *td;
faultbuf env, *oldfault;
int rv;
td = PCPU_GET(curthread);
oldfault = td->td_pcb->pcb_onfault;
if ((rv = setfault(env)) != 0) {
td->td_pcb->pcb_onfault = oldfault;
return rv;
}
memcpy(dst, src, len);
td->td_pcb->pcb_onfault = oldfault;
return (0);
}