freebsd-dev/sys/powerpc/aim/machdep.c
Daniel Eischen 2be05b70c9 Add getcontext, setcontext, and swapcontext as system calls.
Previously these were libc functions but were requested to
be made into system calls for atomicity and to coalesce what
might be two entrances into the kernel (signal mask setting
and floating point trap) into one.

A few style nits and comments from bde are also included.

Tested on alpha by: gallatin
2002-11-16 06:35:53 +00:00

830 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);
/*
* 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);
}