trap.c revision 1.40.10.5 1 /* $NetBSD: trap.c,v 1.40.10.5 2007/10/03 19:24:42 garbled Exp $ */
2
3 /*
4 * Copyright 2001 Wasabi Systems, Inc.
5 * All rights reserved.
6 *
7 * Written by Eduardo Horvath and Simon Burge for Wasabi Systems, Inc.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 * 3. All advertising materials mentioning features or use of this software
18 * must display the following acknowledgement:
19 * This product includes software developed for the NetBSD Project by
20 * Wasabi Systems, Inc.
21 * 4. The name of Wasabi Systems, Inc. may not be used to endorse
22 * or promote products derived from this software without specific prior
23 * written permission.
24 *
25 * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND
26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
27 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
28 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL WASABI SYSTEMS, INC
29 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
30 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
31 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
32 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
33 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
34 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
35 * POSSIBILITY OF SUCH DAMAGE.
36 */
37
38 /*
39 * Copyright (C) 1995, 1996 Wolfgang Solfrank.
40 * Copyright (C) 1995, 1996 TooLs GmbH.
41 * All rights reserved.
42 *
43 * Redistribution and use in source and binary forms, with or without
44 * modification, are permitted provided that the following conditions
45 * are met:
46 * 1. Redistributions of source code must retain the above copyright
47 * notice, this list of conditions and the following disclaimer.
48 * 2. Redistributions in binary form must reproduce the above copyright
49 * notice, this list of conditions and the following disclaimer in the
50 * documentation and/or other materials provided with the distribution.
51 * 3. All advertising materials mentioning features or use of this software
52 * must display the following acknowledgement:
53 * This product includes software developed by TooLs GmbH.
54 * 4. The name of TooLs GmbH may not be used to endorse or promote products
55 * derived from this software without specific prior written permission.
56 *
57 * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR
58 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
59 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
60 * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
61 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
62 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
63 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
64 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
65 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
66 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
67 */
68
69 #include <sys/cdefs.h>
70 __KERNEL_RCSID(0, "$NetBSD: trap.c,v 1.40.10.5 2007/10/03 19:24:42 garbled Exp $");
71
72 #include "opt_altivec.h"
73 #include "opt_ddb.h"
74 #include "opt_kgdb.h"
75
76 #include <sys/param.h>
77 #include <sys/proc.h>
78 #include <sys/reboot.h>
79 #include <sys/syscall.h>
80 #include <sys/systm.h>
81 #include <sys/user.h>
82 #include <sys/pool.h>
83 #include <sys/userret.h>
84 #include <sys/kauth.h>
85
86 #if defined(KGDB)
87 #include <sys/kgdb.h>
88 #endif
89
90 #include <uvm/uvm_extern.h>
91
92 #include <dev/cons.h>
93
94 #include <machine/cpu.h>
95 #include <machine/db_machdep.h>
96 #include <machine/fpu.h>
97 #include <machine/frame.h>
98 #include <machine/pcb.h>
99 #include <machine/psl.h>
100 #include <machine/trap.h>
101
102 #include <powerpc/spr.h>
103 #include <powerpc/ibm4xx/pmap.h>
104 #include <powerpc/ibm4xx/tlb.h>
105 #include <powerpc/fpu/fpu_extern.h>
106
107 /* These definitions should probably be somewhere else XXX */
108 #define FIRSTARG 3 /* first argument is in reg 3 */
109 #define NARGREG 8 /* 8 args are in registers */
110 #define MOREARGS(sp) ((void *)((int)(sp) + 8)) /* more args go here */
111
112 static int fix_unaligned __P((struct lwp *l, struct trapframe *frame));
113
114 void trap __P((struct trapframe *)); /* Called from locore / trap_subr */
115 /* Why are these not defined in a header? */
116 int badaddr __P((void *, size_t));
117 int badaddr_read __P((void *, size_t, int *));
118 int ctx_setup __P((int, int));
119
120 #ifdef DEBUG
121 #define TDB_ALL 0x1
122 int trapdebug = /* TDB_ALL */ 0;
123 #define DBPRINTF(x, y) if (trapdebug & (x)) printf y
124 #else
125 #define DBPRINTF(x, y)
126 #endif
127
128 void
129 trap(struct trapframe *frame)
130 {
131 struct lwp *l = curlwp;
132 struct proc *p = l ? l->l_proc : NULL;
133 int type = frame->exc;
134 int ftype, rv;
135 ksiginfo_t ksi;
136
137 KASSERT(l == 0 || (l->l_stat == LSONPROC));
138
139 if (frame->srr1 & PSL_PR) {
140 LWP_CACHE_CREDS(l, p);
141 type |= EXC_USER;
142 }
143
144 ftype = VM_PROT_READ;
145
146 DBPRINTF(TDB_ALL, ("trap(%x) at %lx from frame %p &frame %p\n",
147 type, frame->srr0, frame, &frame));
148
149 switch (type) {
150 case EXC_DEBUG|EXC_USER:
151 {
152 int srr2, srr3;
153
154 __asm volatile("mfspr %0,0x3f0" :
155 "=r" (rv), "=r" (srr2), "=r" (srr3) :);
156 printf("debug reg is %x srr2 %x srr3 %x\n", rv, srr2,
157 srr3);
158 /* XXX fall through or break here?! */
159 }
160 /*
161 * DEBUG intr -- probably single-step.
162 */
163 case EXC_TRC|EXC_USER:
164 frame->srr1 &= ~PSL_SE;
165 KSI_INIT_TRAP(&ksi);
166 ksi.ksi_signo = SIGTRAP;
167 ksi.ksi_trap = EXC_TRC;
168 ksi.ksi_addr = (void *)frame->srr0;
169 KERNEL_LOCK(1, l);
170 trapsignal(l, &ksi);
171 KERNEL_UNLOCK_LAST(l);
172 break;
173
174 /*
175 * If we could not find and install appropriate TLB entry, fall through.
176 */
177
178 case EXC_DSI:
179 /* FALLTHROUGH */
180 case EXC_DTMISS:
181 {
182 struct vm_map *map;
183 vaddr_t va;
184 struct faultbuf *fb = NULL;
185
186 KERNEL_LOCK(1, NULL);
187 va = frame->dar;
188 if (frame->tf_xtra[TF_PID] == KERNEL_PID) {
189 map = kernel_map;
190 } else {
191 map = &p->p_vmspace->vm_map;
192 }
193
194 if (frame->tf_xtra[TF_ESR] & (ESR_DST|ESR_DIZ))
195 ftype = VM_PROT_WRITE;
196
197 DBPRINTF(TDB_ALL,
198 ("trap(EXC_DSI) at %lx %s fault on %p esr %x\n",
199 frame->srr0,
200 (ftype & VM_PROT_WRITE) ? "write" : "read",
201 (void *)va, frame->tf_xtra[TF_ESR]));
202 rv = uvm_fault(map, trunc_page(va), ftype);
203 KERNEL_UNLOCK_ONE(NULL);
204 if (rv == 0)
205 goto done;
206 if ((fb = l->l_addr->u_pcb.pcb_onfault) != NULL) {
207 frame->tf_xtra[TF_PID] = KERNEL_PID;
208 frame->srr0 = fb->fb_pc;
209 frame->srr1 |= PSL_IR; /* Re-enable IMMU */
210 frame->fixreg[1] = fb->fb_sp;
211 frame->fixreg[2] = fb->fb_r2;
212 frame->fixreg[3] = 1; /* Return TRUE */
213 frame->cr = fb->fb_cr;
214 memcpy(&frame->fixreg[13], fb->fb_fixreg,
215 sizeof(fb->fb_fixreg));
216 goto done;
217 }
218 }
219 goto brain_damage;
220
221 case EXC_DSI|EXC_USER:
222 /* FALLTHROUGH */
223 case EXC_DTMISS|EXC_USER:
224 KERNEL_LOCK(1, l);
225
226 if (frame->tf_xtra[TF_ESR] & (ESR_DST|ESR_DIZ))
227 ftype = VM_PROT_WRITE;
228
229 DBPRINTF(TDB_ALL,
230 ("trap(EXC_DSI|EXC_USER) at %lx %s fault on %lx %x\n",
231 frame->srr0, (ftype & VM_PROT_WRITE) ? "write" : "read",
232 frame->dar, frame->tf_xtra[TF_ESR]));
233 KASSERT(l == curlwp && (l->l_stat == LSONPROC));
234 rv = uvm_fault(&p->p_vmspace->vm_map, trunc_page(frame->dar),
235 ftype);
236 if (rv == 0) {
237 KERNEL_UNLOCK_LAST(l);
238 break;
239 }
240 KSI_INIT_TRAP(&ksi);
241 ksi.ksi_signo = SIGSEGV;
242 ksi.ksi_trap = EXC_DSI;
243 ksi.ksi_addr = (void *)frame->dar;
244 if (rv == ENOMEM) {
245 printf("UVM: pid %d (%s) lid %d, uid %d killed: "
246 "out of swap\n",
247 p->p_pid, p->p_comm, l->l_lid,
248 l->l_cred ?
249 kauth_cred_geteuid(l->l_cred) : -1);
250 ksi.ksi_signo = SIGKILL;
251 }
252 trapsignal(l, &ksi);
253 KERNEL_UNLOCK_LAST(l);
254 break;
255
256 case EXC_ITMISS|EXC_USER:
257 case EXC_ISI|EXC_USER:
258 KERNEL_LOCK(1, l);
259 ftype = VM_PROT_EXECUTE;
260 DBPRINTF(TDB_ALL,
261 ("trap(EXC_ISI|EXC_USER) at %lx execute fault tf %p\n",
262 frame->srr0, frame));
263 rv = uvm_fault(&p->p_vmspace->vm_map, trunc_page(frame->srr0),
264 ftype);
265 if (rv == 0) {
266 KERNEL_UNLOCK_LAST(l);
267 break;
268 }
269 KSI_INIT_TRAP(&ksi);
270 ksi.ksi_signo = SIGSEGV;
271 ksi.ksi_trap = EXC_ISI;
272 ksi.ksi_addr = (void *)frame->srr0;
273 ksi.ksi_code = (rv == EACCES ? SEGV_ACCERR : SEGV_MAPERR);
274 trapsignal(l, &ksi);
275 KERNEL_UNLOCK_LAST(l);
276 break;
277
278 case EXC_AST|EXC_USER:
279 curcpu()->ci_astpending = 0; /* we are about to do it */
280 uvmexp.softs++;
281 if (l->l_pflag & LP_OWEUPC) {
282 l->l_pflag &= ~LP_OWEUPC;
283 ADDUPROF(l);
284 }
285 /* Check whether we are being preempted. */
286 if (curcpu()->ci_want_resched)
287 preempt();
288 break;
289
290
291 case EXC_ALI|EXC_USER:
292 KERNEL_LOCK(1, l);
293 if (fix_unaligned(l, frame) != 0) {
294 KSI_INIT_TRAP(&ksi);
295 ksi.ksi_signo = SIGBUS;
296 ksi.ksi_trap = EXC_ALI;
297 ksi.ksi_addr = (void *)frame->dar;
298 trapsignal(l, &ksi);
299 } else
300 frame->srr0 += 4;
301 KERNEL_UNLOCK_LAST(l);
302 break;
303
304 case EXC_PGM|EXC_USER:
305 /*
306 * Illegal insn:
307 *
308 * let's try to see if it's FPU and can be emulated.
309 */
310 uvmexp.traps++;
311 if (!(l->l_addr->u_pcb.pcb_flags & PCB_FPU)) {
312 memset(&l->l_addr->u_pcb.pcb_fpu, 0,
313 sizeof l->l_addr->u_pcb.pcb_fpu);
314 l->l_addr->u_pcb.pcb_flags |= PCB_FPU;
315 }
316
317 if ((rv = fpu_emulate(frame,
318 (struct fpreg *)&l->l_addr->u_pcb.pcb_fpu))) {
319 KSI_INIT_TRAP(&ksi);
320 ksi.ksi_signo = rv;
321 ksi.ksi_trap = EXC_PGM;
322 ksi.ksi_addr = (void *)frame->srr0;
323 KERNEL_LOCK(1, l);
324 trapsignal(l, &ksi);
325 KERNEL_UNLOCK_LAST(l);
326 }
327 break;
328
329 case EXC_MCHK:
330 {
331 struct faultbuf *fb;
332
333 if ((fb = l->l_addr->u_pcb.pcb_onfault) != NULL) {
334 frame->tf_xtra[TF_PID] = KERNEL_PID;
335 frame->srr0 = fb->fb_pc;
336 frame->srr1 |= PSL_IR; /* Re-enable IMMU */
337 frame->fixreg[1] = fb->fb_sp;
338 frame->fixreg[2] = fb->fb_r2;
339 frame->fixreg[3] = 1; /* Return TRUE */
340 frame->cr = fb->fb_cr;
341 memcpy(&frame->fixreg[13], fb->fb_fixreg,
342 sizeof(fb->fb_fixreg));
343 goto done;
344 }
345 }
346 goto brain_damage;
347 default:
348 brain_damage:
349 printf("trap type 0x%x at 0x%lx\n", type, frame->srr0);
350 #if defined(DDB) || defined(KGDB)
351 if (kdb_trap(type, frame))
352 goto done;
353 #endif
354 #ifdef TRAP_PANICWAIT
355 printf("Press a key to panic.\n");
356 cngetc();
357 #endif
358 panic("trap");
359 }
360
361 /* Invoke MI userret code */
362 mi_userret(l);
363
364 curcpu()->ci_schedstate.spc_curpriority = l->l_priority = l->l_usrpri;
365 done:
366 return;
367 }
368
369 int
370 ctx_setup(int ctx, int srr1)
371 {
372 volatile struct pmap *pm;
373
374 /* Update PID if we're returning to user mode. */
375 if (srr1 & PSL_PR) {
376 pm = curproc->p_vmspace->vm_map.pmap;
377 if (!pm->pm_ctx) {
378 ctx_alloc(__UNVOLATILE(pm));
379 }
380 ctx = pm->pm_ctx;
381 if (srr1 & PSL_SE) {
382 int dbreg, mask = 0x48000000;
383 /*
384 * Set the Internal Debug and
385 * Instruction Completion bits of
386 * the DBCR0 register.
387 *
388 * XXX this is also used by jtag debuggers...
389 */
390 __asm volatile("mfspr %0,0x3f2;"
391 "or %0,%0,%1;"
392 "mtspr 0x3f2,%0;" :
393 "=&r" (dbreg) : "r" (mask));
394 }
395 }
396 else if (!ctx) {
397 ctx = KERNEL_PID;
398 }
399 return (ctx);
400 }
401
402 /*
403 * Used by copyin()/copyout()
404 */
405 extern vaddr_t vmaprange __P((struct proc *, vaddr_t, vsize_t, int));
406 extern void vunmaprange __P((vaddr_t, vsize_t));
407 static int bigcopyin __P((const void *, void *, size_t ));
408 static int bigcopyout __P((const void *, void *, size_t ));
409
410 int
411 copyin(const void *udaddr, void *kaddr, size_t len)
412 {
413 struct pmap *pm = curproc->p_vmspace->vm_map.pmap;
414 int msr, pid, tmp, ctx;
415 struct faultbuf env;
416
417 /* For bigger buffers use the faster copy */
418 if (len > 256)
419 return (bigcopyin(udaddr, kaddr, len));
420
421 if (setfault(&env)) {
422 curpcb->pcb_onfault = 0;
423 return EFAULT;
424 }
425
426 if (!(ctx = pm->pm_ctx)) {
427 /* No context -- assign it one */
428 ctx_alloc(pm);
429 ctx = pm->pm_ctx;
430 }
431
432 __asm volatile("addi %6,%6,1; mtctr %6;" /* Set up counter */
433 "mfmsr %0;" /* Save MSR */
434 "li %1,0x20; "
435 "andc %1,%0,%1; mtmsr %1;" /* Disable IMMU */
436 "mfpid %1;" /* Save old PID */
437 "sync; isync;"
438
439 "1: bdz 2f;" /* while len */
440 "mtpid %3; sync;" /* Load user ctx */
441 "lbz %2,0(%4); addi %4,%4,1;" /* Load byte */
442 "sync; isync;"
443 "mtpid %1;sync;"
444 "stb %2,0(%5); dcbf 0,%5; addi %5,%5,1;" /* Store kernel byte */
445 "sync; isync;"
446 "b 1b;" /* repeat */
447
448 "2: mtpid %1; mtmsr %0;" /* Restore PID and MSR */
449 "sync; isync;"
450 : "=&r" (msr), "=&r" (pid), "=&r" (tmp)
451 : "r" (ctx), "b" (udaddr), "b" (kaddr), "b" (len));
452
453 curpcb->pcb_onfault = 0;
454 return 0;
455 }
456
457 static int
458 bigcopyin(const void *udaddr, void *kaddr, size_t len)
459 {
460 const char *up;
461 char *kp = kaddr;
462 struct lwp *l = curlwp;
463 struct proc *p;
464 int error;
465
466 if (!l) {
467 return EFAULT;
468 }
469
470 p = l->l_proc;
471
472 /*
473 * Stolen from physio():
474 */
475 uvm_lwp_hold(l);
476 error = uvm_vslock(p->p_vmspace, __UNCONST(udaddr), len, VM_PROT_READ);
477 if (error) {
478 uvm_lwp_rele(l);
479 return EFAULT;
480 }
481 up = (char *)vmaprange(p, (vaddr_t)udaddr, len, VM_PROT_READ);
482
483 memcpy(kp, up, len);
484 vunmaprange((vaddr_t)up, len);
485 uvm_vsunlock(p->p_vmspace, __UNCONST(udaddr), len);
486 uvm_lwp_rele(l);
487
488 return 0;
489 }
490
491 int
492 copyout(const void *kaddr, void *udaddr, size_t len)
493 {
494 struct pmap *pm = curproc->p_vmspace->vm_map.pmap;
495 int msr, pid, tmp, ctx;
496 struct faultbuf env;
497
498 /* For big copies use more efficient routine */
499 if (len > 256)
500 return (bigcopyout(kaddr, udaddr, len));
501
502 if (setfault(&env)) {
503 curpcb->pcb_onfault = 0;
504 return EFAULT;
505 }
506
507 if (!(ctx = pm->pm_ctx)) {
508 /* No context -- assign it one */
509 ctx_alloc(pm);
510 ctx = pm->pm_ctx;
511 }
512
513 __asm volatile("addi %6,%6,1; mtctr %6;" /* Set up counter */
514 "mfmsr %0;" /* Save MSR */
515 "li %1,0x20; "
516 "andc %1,%0,%1; mtmsr %1;" /* Disable IMMU */
517 "mfpid %1;" /* Save old PID */
518 "sync; isync;"
519
520 "1: bdz 2f;" /* while len */
521 "mtpid %1;sync;"
522 "lbz %2,0(%5); addi %5,%5,1;" /* Load kernel byte */
523 "sync; isync;"
524 "mtpid %3; sync;" /* Load user ctx */
525 "stb %2,0(%4); dcbf 0,%4; addi %4,%4,1;" /* Store user byte */
526 "sync; isync;"
527 "b 1b;" /* repeat */
528
529 "2: mtpid %1; mtmsr %0;" /* Restore PID and MSR */
530 "sync; isync;"
531 : "=&r" (msr), "=&r" (pid), "=&r" (tmp)
532 : "r" (ctx), "b" (udaddr), "b" (kaddr), "b" (len));
533
534 curpcb->pcb_onfault = 0;
535 return 0;
536 }
537
538 static int
539 bigcopyout(const void *kaddr, void *udaddr, size_t len)
540 {
541 char *up;
542 const char *kp = (const char *)kaddr;
543 struct lwp *l = curlwp;
544 struct proc *p;
545 int error;
546
547 if (!l) {
548 return EFAULT;
549 }
550
551 p = l->l_proc;
552
553 /*
554 * Stolen from physio():
555 */
556 uvm_lwp_hold(l);
557 error = uvm_vslock(p->p_vmspace, udaddr, len, VM_PROT_WRITE);
558 if (error) {
559 uvm_lwp_rele(l);
560 return EFAULT;
561 }
562 up = (char *)vmaprange(p, (vaddr_t)udaddr, len,
563 VM_PROT_READ | VM_PROT_WRITE);
564
565 memcpy(up, kp, len);
566 vunmaprange((vaddr_t)up, len);
567 uvm_vsunlock(p->p_vmspace, udaddr, len);
568 uvm_lwp_rele(l);
569
570 return 0;
571 }
572
573 /*
574 * kcopy(const void *src, void *dst, size_t len);
575 *
576 * Copy len bytes from src to dst, aborting if we encounter a fatal
577 * page fault.
578 *
579 * kcopy() _must_ save and restore the old fault handler since it is
580 * called by uiomove(), which may be in the path of servicing a non-fatal
581 * page fault.
582 */
583 int
584 kcopy(const void *src, void *dst, size_t len)
585 {
586 struct faultbuf env, *oldfault;
587
588 oldfault = curpcb->pcb_onfault;
589 if (setfault(&env)) {
590 curpcb->pcb_onfault = oldfault;
591 return EFAULT;
592 }
593
594 memcpy(dst, src, len);
595
596 curpcb->pcb_onfault = oldfault;
597 return 0;
598 }
599
600 int
601 badaddr(void *addr, size_t size)
602 {
603
604 return badaddr_read(addr, size, NULL);
605 }
606
607 int
608 badaddr_read(void *addr, size_t size, int *rptr)
609 {
610 struct faultbuf env;
611 int x;
612
613 /* Get rid of any stale machine checks that have been waiting. */
614 __asm volatile ("sync; isync");
615
616 if (setfault(&env)) {
617 curpcb->pcb_onfault = 0;
618 __asm volatile ("sync");
619 return 1;
620 }
621
622 __asm volatile ("sync");
623
624 switch (size) {
625 case 1:
626 x = *(volatile int8_t *)addr;
627 break;
628 case 2:
629 x = *(volatile int16_t *)addr;
630 break;
631 case 4:
632 x = *(volatile int32_t *)addr;
633 break;
634 default:
635 panic("badaddr: invalid size (%d)", size);
636 }
637
638 /* Make sure we took the machine check, if we caused one. */
639 __asm volatile ("sync; isync");
640
641 curpcb->pcb_onfault = 0;
642 __asm volatile ("sync"); /* To be sure. */
643
644 /* Use the value to avoid reorder. */
645 if (rptr)
646 *rptr = x;
647
648 return 0;
649 }
650
651 /*
652 * For now, this only deals with the particular unaligned access case
653 * that gcc tends to generate. Eventually it should handle all of the
654 * possibilities that can happen on a 32-bit PowerPC in big-endian mode.
655 */
656
657 static int
658 fix_unaligned(struct lwp *l, struct trapframe *frame)
659 {
660
661 return -1;
662 }
663
664 /*
665 * Start a new LWP
666 */
667 void
668 startlwp(arg)
669 void *arg;
670 {
671 int err;
672 ucontext_t *uc = arg;
673 struct lwp *l = curlwp;
674
675 err = cpu_setmcontext(l, &uc->uc_mcontext, uc->uc_flags);
676 #if DIAGNOSTIC
677 if (err) {
678 printf("Error %d from cpu_setmcontext.", err);
679 }
680 #endif
681 pool_put(&lwp_uc_pool, uc);
682
683 /* Invoke MI userret code */
684 mi_userret(l);
685
686 curcpu()->ci_schedstate.spc_curpriority = l->l_priority = l->l_usrpri;
687 }
688