xref: /netbsd-src/sys/arch/powerpc/ibm4xx/trap.c (revision da5f4674a3fc214be3572d358b66af40ab9401e7)
1 /*	$NetBSD: trap.c,v 1.15 2003/08/24 17:52:34 chs 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 1.15 2003/08/24 17:52:34 chs Exp $");
71 
72 #include "opt_altivec.h"
73 #include "opt_ddb.h"
74 #include "opt_ktrace.h"
75 #include "opt_systrace.h"
76 #include "opt_syscall_debug.h"
77 
78 #include <sys/param.h>
79 #include <sys/proc.h>
80 #include <sys/reboot.h>
81 #include <sys/syscall.h>
82 #include <sys/systm.h>
83 #include <sys/user.h>
84 #ifdef KTRACE
85 #include <sys/ktrace.h>
86 #endif
87 #include <sys/pool.h>
88 #include <sys/sa.h>
89 #include <sys/savar.h>
90 #ifdef SYSTRACE
91 #include <sys/systrace.h>
92 #endif
93 
94 #include <uvm/uvm_extern.h>
95 
96 #include <dev/cons.h>
97 
98 #include <machine/cpu.h>
99 #include <machine/db_machdep.h>
100 #include <machine/fpu.h>
101 #include <machine/frame.h>
102 #include <machine/pcb.h>
103 #include <machine/psl.h>
104 #include <machine/trap.h>
105 
106 #include <powerpc/spr.h>
107 #include <powerpc/ibm4xx/pmap.h>
108 #include <powerpc/ibm4xx/tlb.h>
109 #include <powerpc/fpu/fpu_extern.h>
110 
111 /* These definitions should probably be somewhere else			XXX */
112 #define	FIRSTARG	3		/* first argument is in reg 3 */
113 #define	NARGREG		8		/* 8 args are in registers */
114 #define	MOREARGS(sp)	((caddr_t)((int)(sp) + 8)) /* more args go here */
115 
116 static int fix_unaligned __P((struct lwp *l, struct trapframe *frame));
117 
118 void trap __P((struct trapframe *));	/* Called from locore / trap_subr */
119 /* Why are these not defined in a header? */
120 int badaddr __P((void *, size_t));
121 int badaddr_read __P((void *, size_t, int *));
122 int ctx_setup __P((int, int));
123 
124 #ifdef DEBUG
125 #define TDB_ALL	0x1
126 int trapdebug = /* TDB_ALL */ 0;
127 #define	DBPRINTF(x, y)	if (trapdebug & (x)) printf y
128 #else
129 #define DBPRINTF(x, y)
130 #endif
131 
132 void
133 trap(struct trapframe *frame)
134 {
135 	struct lwp *l = curlwp;
136 	struct proc *p = l ? l->l_proc : NULL;
137 	int type = frame->exc;
138 	int ftype, rv;
139 
140 	KASSERT(l == 0 || (l->l_stat == LSONPROC));
141 
142 	if (frame->srr1 & PSL_PR)
143 		type |= EXC_USER;
144 
145 	ftype = VM_PROT_READ;
146 
147 	DBPRINTF(TDB_ALL, ("trap(%x) at %lx from frame %p &frame %p\n",
148 	    type, frame->srr0, frame, &frame));
149 
150 	switch (type) {
151 	case EXC_DEBUG|EXC_USER:
152 		{
153 			int srr2, srr3;
154 
155 			__asm __volatile("mfspr %0,0x3f0" :
156 			    "=r" (rv), "=r" (srr2), "=r" (srr3) :);
157 			printf("debug reg is %x srr2 %x srr3 %x\n", rv, srr2,
158 			    srr3);
159 			/* XXX fall through or break here?! */
160 		}
161 		/*
162 		 * DEBUG intr -- probably single-step.
163 		 */
164 	case EXC_TRC|EXC_USER:
165 		KERNEL_PROC_LOCK(l);
166 		frame->srr1 &= ~PSL_SE;
167 		trapsignal(l, SIGTRAP, EXC_TRC);
168 		KERNEL_PROC_UNLOCK(l);
169 		break;
170 
171 	/*
172 	 * If we could not find and install appropriate TLB entry, fall through.
173 	 */
174 
175 	case EXC_DSI:
176 		/* FALLTHROUGH */
177 	case EXC_DTMISS:
178 		{
179 			struct vm_map *map;
180 			vaddr_t va;
181 			struct faultbuf *fb = NULL;
182 
183 			KERNEL_LOCK(LK_CANRECURSE|LK_EXCLUSIVE);
184 			va = frame->dar;
185 			if (frame->tf_xtra[TF_PID] == KERNEL_PID) {
186 				map = kernel_map;
187 			} else {
188 				map = &p->p_vmspace->vm_map;
189 			}
190 
191 			if (frame->tf_xtra[TF_ESR] & (ESR_DST|ESR_DIZ))
192 				ftype = VM_PROT_WRITE;
193 
194 			DBPRINTF(TDB_ALL,
195 			    ("trap(EXC_DSI) at %lx %s fault on %p esr %x\n",
196 			    frame->srr0,
197 			    (ftype & VM_PROT_WRITE) ? "write" : "read",
198 			    (void *)va, frame->tf_xtra[TF_ESR]));
199 			rv = uvm_fault(map, trunc_page(va), 0, ftype);
200 			KERNEL_UNLOCK();
201 			if (rv == 0)
202 				goto done;
203 			if ((fb = l->l_addr->u_pcb.pcb_onfault) != NULL) {
204 				frame->tf_xtra[TF_PID] = KERNEL_PID;
205 				frame->srr0 = fb->fb_pc;
206 				frame->srr1 |= PSL_IR; /* Re-enable IMMU */
207 				frame->fixreg[1] = fb->fb_sp;
208 				frame->fixreg[2] = fb->fb_r2;
209 				frame->fixreg[3] = 1; /* Return TRUE */
210 				frame->cr = fb->fb_cr;
211 				memcpy(&frame->fixreg[13], fb->fb_fixreg,
212 				    sizeof(fb->fb_fixreg));
213 				goto done;
214 			}
215 		}
216 		goto brain_damage;
217 
218 	case EXC_DSI|EXC_USER:
219 		/* FALLTHROUGH */
220 	case EXC_DTMISS|EXC_USER:
221 		KERNEL_PROC_LOCK(l);
222 
223 		if (frame->tf_xtra[TF_ESR] & (ESR_DST|ESR_DIZ))
224 			ftype = VM_PROT_WRITE;
225 
226 		DBPRINTF(TDB_ALL,
227 		    ("trap(EXC_DSI|EXC_USER) at %lx %s fault on %lx %x\n",
228 		    frame->srr0, (ftype & VM_PROT_WRITE) ? "write" : "read",
229 		    frame->dar, frame->tf_xtra[TF_ESR]));
230 		KASSERT(l == curlwp && (l->l_stat == LSONPROC));
231 		rv = uvm_fault(&p->p_vmspace->vm_map, trunc_page(frame->dar),
232 		    0, ftype);
233 		if (rv == 0) {
234 			KERNEL_PROC_UNLOCK(l);
235 			break;
236 		}
237 		if (rv == ENOMEM) {
238 			printf("UVM: pid %d (%s) lid %d, uid %d killed: "
239 			    "out of swap\n",
240 			    p->p_pid, p->p_comm, l->l_lid,
241 			    p->p_cred && p->p_ucred ?
242 			    p->p_ucred->cr_uid : -1);
243 			trapsignal(l, SIGKILL, EXC_DSI);
244 		} else {
245 			trapsignal(l, SIGSEGV, EXC_DSI);
246 		}
247 		KERNEL_PROC_UNLOCK(l);
248 		break;
249 
250 	case EXC_ITMISS|EXC_USER:
251 	case EXC_ISI|EXC_USER:
252 		KERNEL_PROC_LOCK(l);
253 		ftype = VM_PROT_EXECUTE;
254 		DBPRINTF(TDB_ALL,
255 		    ("trap(EXC_ISI|EXC_USER) at %lx execute fault tf %p\n",
256 		    frame->srr0, frame));
257 		rv = uvm_fault(&p->p_vmspace->vm_map, trunc_page(frame->srr0),
258 		    0, ftype);
259 		if (rv == 0) {
260 			KERNEL_PROC_UNLOCK(l);
261 			break;
262 		}
263 		trapsignal(l, SIGSEGV, EXC_ISI);
264 		KERNEL_PROC_UNLOCK(l);
265 		break;
266 
267 	case EXC_AST|EXC_USER:
268 		curcpu()->ci_astpending = 0;	/* we are about to do it */
269 		KERNEL_PROC_LOCK(l);
270 		uvmexp.softs++;
271 		if (p->p_flag & P_OWEUPC) {
272 			p->p_flag &= ~P_OWEUPC;
273 			ADDUPROF(p);
274 		}
275 		/* Check whether we are being preempted. */
276 		if (curcpu()->ci_want_resched)
277 			preempt(0);
278 		KERNEL_PROC_UNLOCK(l);
279 		break;
280 
281 
282 	case EXC_ALI|EXC_USER:
283 		KERNEL_PROC_LOCK(l);
284 		if (fix_unaligned(l, frame) != 0)
285 			trapsignal(l, SIGBUS, EXC_ALI);
286 		else
287 			frame->srr0 += 4;
288 		KERNEL_PROC_UNLOCK(l);
289 		break;
290 
291 	case EXC_PGM|EXC_USER:
292 		/*
293 		 * Illegal insn:
294 		 *
295 		 * let's try to see if it's FPU and can be emulated.
296 		 */
297 		uvmexp.traps ++;
298 		if (!(l->l_addr->u_pcb.pcb_flags & PCB_FPU)) {
299 			memset(&l->l_addr->u_pcb.pcb_fpu, 0,
300 				sizeof l->l_addr->u_pcb.pcb_fpu);
301 			l->l_addr->u_pcb.pcb_flags |= PCB_FPU;
302 		}
303 
304 		if ((rv = fpu_emulate(frame,
305 			(struct fpreg *)&l->l_addr->u_pcb.pcb_fpu))) {
306 			KERNEL_PROC_LOCK(l);
307 			trapsignal(l, rv, EXC_PGM);
308 			KERNEL_PROC_UNLOCK(l);
309 		}
310 		break;
311 
312 	case EXC_MCHK:
313 		{
314 			struct faultbuf *fb;
315 
316 			if ((fb = l->l_addr->u_pcb.pcb_onfault) != NULL) {
317 				frame->tf_xtra[TF_PID] = KERNEL_PID;
318 				frame->srr0 = fb->fb_pc;
319 				frame->srr1 |= PSL_IR; /* Re-enable IMMU */
320 				frame->fixreg[1] = fb->fb_sp;
321 				frame->fixreg[2] = fb->fb_r2;
322 				frame->fixreg[3] = 1; /* Return TRUE */
323 				frame->cr = fb->fb_cr;
324 				memcpy(&frame->fixreg[13], fb->fb_fixreg,
325 				    sizeof(fb->fb_fixreg));
326 				goto done;
327 			}
328 		}
329 		goto brain_damage;
330 	default:
331  brain_damage:
332 		printf("trap type 0x%x at 0x%lx\n", type, frame->srr0);
333 #ifdef DDB
334 		if (kdb_trap(type, frame))
335 			goto done;
336 #endif
337 #ifdef TRAP_PANICWAIT
338 		printf("Press a key to panic.\n");
339 		cngetc();
340 #endif
341 		panic("trap");
342 	}
343 
344 	/* Take pending signals. */
345 	{
346 		int sig;
347 
348 		while ((sig = CURSIG(l)) != 0)
349 			postsig(sig);
350 	}
351 
352 	/* Invoke per-process kernel-exit handling, if any */
353 	if (p->p_userret)
354 		(p->p_userret)(l, p->p_userret_arg);
355 
356 	/* Invoke any pending upcalls */
357 	while (l->l_flag & L_SA_UPCALL)
358 		sa_upcall_userret(l);
359 
360 	curcpu()->ci_schedstate.spc_curpriority = l->l_priority = l->l_usrpri;
361  done:
362 	return;
363 }
364 
365 int
366 ctx_setup(int ctx, int srr1)
367 {
368 	volatile struct pmap *pm;
369 
370 	/* Update PID if we're returning to user mode. */
371 	if (srr1 & PSL_PR) {
372 		pm = curproc->p_vmspace->vm_map.pmap;
373 		if (!pm->pm_ctx) {
374 			ctx_alloc((struct pmap *)pm);
375 		}
376 		ctx = pm->pm_ctx;
377 		if (srr1 & PSL_SE) {
378 			int dbreg, mask = 0x48000000;
379 				/*
380 				 * Set the Internal Debug and
381 				 * Instruction Completion bits of
382 				 * the DBCR0 register.
383 				 *
384 				 * XXX this is also used by jtag debuggers...
385 				 */
386 			__asm __volatile("mfspr %0,0x3f2;"
387 			    "or %0,%0,%1;"
388 			    "mtspr 0x3f2,%0;" :
389 			    "=&r" (dbreg) : "r" (mask));
390 		}
391 	}
392 	else if (!ctx) {
393 		ctx = KERNEL_PID;
394 	}
395 	return (ctx);
396 }
397 
398 /*
399  * Used by copyin()/copyout()
400  */
401 extern vaddr_t vmaprange __P((struct proc *, vaddr_t, vsize_t, int));
402 extern void vunmaprange __P((vaddr_t, vsize_t));
403 static int bigcopyin __P((const void *, void *, size_t ));
404 static int bigcopyout __P((const void *, void *, size_t ));
405 
406 int
407 copyin(const void *udaddr, void *kaddr, size_t len)
408 {
409 	struct pmap *pm = curproc->p_vmspace->vm_map.pmap;
410 	int msr, pid, tmp, ctx;
411 	struct faultbuf env;
412 
413 	/* For bigger buffers use the faster copy */
414 	if (len > 256) return (bigcopyin(udaddr, kaddr, len));
415 
416 	if (setfault(&env)) {
417 		curpcb->pcb_onfault = 0;
418 		return EFAULT;
419 	}
420 
421 	if (!(ctx = pm->pm_ctx)) {
422 		/* No context -- assign it one */
423 		ctx_alloc(pm);
424 		ctx = pm->pm_ctx;
425 	}
426 
427 	asm volatile("addi %6,%6,1; mtctr %6;"	/* Set up counter */
428 		"mfmsr %0;"			/* Save MSR */
429 		"li %1,0x20; "
430 		"andc %1,%0,%1; mtmsr %1;"	/* Disable IMMU */
431 		"mfpid %1;"			/* Save old PID */
432 		"sync; isync;"
433 
434 		"1: bdz 2f;"			/* while len */
435 		"mtpid %3; sync;"		/* Load user ctx */
436 		"lbz %2,0(%4); addi %4,%4,1;"	/* Load byte */
437 		"sync; isync;"
438 		"mtpid %1;sync;"
439 		"stb %2,0(%5); dcbf 0,%5; addi %5,%5,1;" /* Store kernel byte */
440 		"sync; isync;"
441 		"b 1b;"				/* repeat */
442 
443 		"2: mtpid %1; mtmsr %0;"	/* Restore PID and MSR */
444 		"sync; isync;"
445 		: "=&r" (msr), "=&r" (pid), "=&r" (tmp)
446 		: "r" (ctx), "r" (udaddr), "r" (kaddr), "r" (len));
447 
448 	curpcb->pcb_onfault = 0;
449 	return 0;
450 }
451 
452 static int
453 bigcopyin(const void *udaddr, void *kaddr, size_t len)
454 {
455 	const char *up;
456 	char *kp = kaddr;
457 	struct lwp *l = curlwp;
458 	struct proc *p;
459 	int error;
460 
461 	if (!l) {
462 		return EFAULT;
463 	}
464 
465 	p = l->l_proc;
466 
467 	/*
468 	 * Stolen from physio():
469 	 */
470 	PHOLD(l);
471 	error = uvm_vslock(p, (caddr_t)udaddr, len, VM_PROT_READ);
472 	if (error) {
473 		PRELE(l);
474 		return EFAULT;
475 	}
476 	up = (char *)vmaprange(p, (vaddr_t)udaddr, len, VM_PROT_READ);
477 
478 	memcpy(kp, up, len);
479 	vunmaprange((vaddr_t)up, len);
480 	uvm_vsunlock(p, (caddr_t)udaddr, len);
481 	PRELE(l);
482 
483 	return 0;
484 }
485 
486 int
487 copyout(const void *kaddr, void *udaddr, size_t len)
488 {
489 	struct pmap *pm = curproc->p_vmspace->vm_map.pmap;
490 	int msr, pid, tmp, ctx;
491 	struct faultbuf env;
492 
493 	/* For big copies use more efficient routine */
494 	if (len > 256) return (bigcopyout(kaddr, udaddr, len));
495 
496 	if (setfault(&env)) {
497 		curpcb->pcb_onfault = 0;
498 		return EFAULT;
499 	}
500 
501 	if (!(ctx = pm->pm_ctx)) {
502 		/* No context -- assign it one */
503 		ctx_alloc(pm);
504 		ctx = pm->pm_ctx;
505 	}
506 
507 	asm volatile("addi %6,%6,1; mtctr %6;"	/* Set up counter */
508 		"mfmsr %0;"			/* Save MSR */
509 		"li %1,0x20; "
510 		"andc %1,%0,%1; mtmsr %1;"	/* Disable IMMU */
511 		"mfpid %1;"			/* Save old PID */
512 		"sync; isync;"
513 
514 		"1: bdz 2f;"			/* while len */
515 		"mtpid %1;sync;"
516 		"lbz %2,0(%5); addi %5,%5,1;"	/* Load kernel byte */
517 		"sync; isync;"
518 		"mtpid %3; sync;"		/* Load user ctx */
519 		"stb %2,0(%4);  dcbf 0,%4; addi %4,%4,1;" /* Store user byte */
520 		"sync; isync;"
521 		"b 1b;"				/* repeat */
522 
523 		"2: mtpid %1; mtmsr %0;"	/* Restore PID and MSR */
524 		"sync; isync;"
525 		: "=&r" (msr), "=&r" (pid), "=&r" (tmp)
526 		: "r" (ctx), "r" (udaddr), "r" (kaddr), "r" (len));
527 
528 	curpcb->pcb_onfault = 0;
529 	return 0;
530 }
531 
532 static int
533 bigcopyout(const void *kaddr, void *udaddr, size_t len)
534 {
535 	char *up;
536 	const char *kp = (char *)kaddr;
537 	struct lwp *l = curlwp;
538 	struct proc *p;
539 	int error;
540 
541 	if (!l) {
542 		return EFAULT;
543 	}
544 
545 	p = l->l_proc;
546 
547 	/*
548 	 * Stolen from physio():
549 	 */
550 	PHOLD(l);
551 	error = uvm_vslock(p, udaddr, len, VM_PROT_WRITE);
552 	if (error) {
553 		PRELE(l);
554 		return EFAULT;
555 	}
556 	up = (char *)vmaprange(p, (vaddr_t)udaddr, len,
557 	    VM_PROT_READ | VM_PROT_WRITE);
558 
559 	memcpy(up, kp, len);
560 	vunmaprange((vaddr_t)up, len);
561 	uvm_vsunlock(p, udaddr, len);
562 	PRELE(l);
563 
564 	return 0;
565 }
566 
567 /*
568  * kcopy(const void *src, void *dst, size_t len);
569  *
570  * Copy len bytes from src to dst, aborting if we encounter a fatal
571  * page fault.
572  *
573  * kcopy() _must_ save and restore the old fault handler since it is
574  * called by uiomove(), which may be in the path of servicing a non-fatal
575  * page fault.
576  */
577 int
578 kcopy(const void *src, void *dst, size_t len)
579 {
580 	struct faultbuf env, *oldfault;
581 
582 	oldfault = curpcb->pcb_onfault;
583 	if (setfault(&env)) {
584 		curpcb->pcb_onfault = oldfault;
585 		return EFAULT;
586 	}
587 
588 	memcpy(dst, src, len);
589 
590 	curpcb->pcb_onfault = oldfault;
591 	return 0;
592 }
593 
594 int
595 badaddr(void *addr, size_t size)
596 {
597 
598 	return badaddr_read(addr, size, NULL);
599 }
600 
601 int
602 badaddr_read(void *addr, size_t size, int *rptr)
603 {
604 	struct faultbuf env;
605 	int x;
606 
607 	/* Get rid of any stale machine checks that have been waiting.  */
608 	__asm __volatile ("sync; isync");
609 
610 	if (setfault(&env)) {
611 		curpcb->pcb_onfault = 0;
612 		__asm __volatile ("sync");
613 		return 1;
614 	}
615 
616 	__asm __volatile ("sync");
617 
618 	switch (size) {
619 	case 1:
620 		x = *(volatile int8_t *)addr;
621 		break;
622 	case 2:
623 		x = *(volatile int16_t *)addr;
624 		break;
625 	case 4:
626 		x = *(volatile int32_t *)addr;
627 		break;
628 	default:
629 		panic("badaddr: invalid size (%d)", size);
630 	}
631 
632 	/* Make sure we took the machine check, if we caused one. */
633 	__asm __volatile ("sync; isync");
634 
635 	curpcb->pcb_onfault = 0;
636 	__asm __volatile ("sync");	/* To be sure. */
637 
638 	/* Use the value to avoid reorder. */
639 	if (rptr)
640 		*rptr = x;
641 
642 	return 0;
643 }
644 
645 /*
646  * For now, this only deals with the particular unaligned access case
647  * that gcc tends to generate.  Eventually it should handle all of the
648  * possibilities that can happen on a 32-bit PowerPC in big-endian mode.
649  */
650 
651 static int
652 fix_unaligned(struct lwp *l, struct trapframe *frame)
653 {
654 
655 	return -1;
656 }
657 
658 /*
659  * Start a new LWP
660  */
661 void
662 startlwp(arg)
663 	void *arg;
664 {
665 	int err;
666 	ucontext_t *uc = arg;
667 	struct lwp *l = curlwp;
668 
669 	err = cpu_setmcontext(l, &uc->uc_mcontext, uc->uc_flags);
670 #if DIAGNOSTIC
671 	if (err) {
672 		printf("Error %d from cpu_setmcontext.", err);
673 	}
674 #endif
675 	pool_put(&lwp_uc_pool, uc);
676 
677 	upcallret(l);
678 }
679 
680 /*
681  * XXX This is a terrible name.
682  */
683 void
684 upcallret(l)
685 	struct lwp *l;
686 {
687 	int sig;
688 
689 	/* Take pending signals. */
690 	while ((sig = CURSIG(l)) != 0)
691 		postsig(sig);
692 
693 	/* Invoke per-process kernel-exit handling, if any */
694 	if (l->l_proc->p_userret)
695 		(l->l_proc->p_userret)(l, l->l_proc->p_userret_arg);
696 
697 	/* Invoke any pending upcalls */
698 	while (l->l_flag & L_SA_UPCALL)
699 		sa_upcall_userret(l);
700 
701 	curcpu()->ci_schedstate.spc_curpriority = l->l_priority = l->l_usrpri;
702 }
703