xref: /netbsd-src/sys/arch/arm/arm32/fault.c (revision 1ca5c1b28139779176bd5c13ad7c5f25c0bcd5f8)
1 /*	$NetBSD: fault.c,v 1.7 2002/01/05 22:41:47 chris Exp $	*/
2 
3 /*
4  * Copyright (c) 1994-1997 Mark Brinicombe.
5  * Copyright (c) 1994 Brini.
6  * All rights reserved.
7  *
8  * This code is derived from software written for Brini by Mark Brinicombe
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. All advertising materials mentioning features or use of this software
19  *    must display the following acknowledgement:
20  *	This product includes software developed by Brini.
21  * 4. The name of the company nor the name of the author may be used to
22  *    endorse or promote products derived from this software without specific
23  *    prior written permission.
24  *
25  * THIS SOFTWARE IS PROVIDED BY BRINI ``AS IS'' AND ANY EXPRESS OR IMPLIED
26  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
27  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
28  * IN NO EVENT SHALL BRINI OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
29  * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
30  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
31  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
32  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
33  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
34  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35  * SUCH DAMAGE.
36  *
37  * RiscBSD kernel project
38  *
39  * fault.c
40  *
41  * Fault handlers
42  *
43  * Created      : 28/11/94
44  */
45 
46 #include "opt_ddb.h"
47 #include "opt_pmap_debug.h"
48 
49 #include <sys/types.h>
50 #include <sys/param.h>
51 #include <sys/systm.h>
52 #include <sys/proc.h>
53 #include <sys/user.h>
54 #include <sys/kernel.h>
55 
56 #include <uvm/uvm_extern.h>
57 
58 #include <machine/frame.h>
59 #include <arm/arm32/katelib.h>
60 #include <machine/cpu.h>
61 #include <machine/intr.h>
62 #ifdef DDB
63 #include <machine/db_machdep.h>
64 #endif
65 
66 #include <arch/arm/arm/disassem.h>
67 #include <arm/arm32/machdep.h>
68 
69 int cowfault __P((vaddr_t));
70 int fetchuserword __P((u_int address, u_int *location));
71 extern char fusubailout[];
72 
73 static void report_abort __P((const char *, u_int, u_int, u_int));
74 
75 /* Abort code */
76 
77 /* Define text descriptions of the different aborts */
78 
79 static const char *aborts[16] = {
80 	"Write buffer fault",
81 	"Alignment fault",
82 	"Write buffer fault",
83 	"Alignment fault",
84 	"Bus error (LF section)",
85 	"Translation fault (section)",
86 	"Bus error (page)",
87 	"Translation fault (page)",
88 	"Bus error (section)",
89 	"Domain error (section)",
90 	"Bus error (page)",
91 	"Domain error (page)",
92 	"Bus error trans (L1)",
93 	"Permission error (section)",
94 	"Bus error trans (L2)",
95 	"Permission error (page)"
96 };
97 
98 static void
99 report_abort(prefix, fault_status, fault_address, fault_pc)
100 	const char *prefix;
101 	u_int fault_status;
102 	u_int fault_address;
103 	u_int fault_pc;
104 {
105 #ifndef DEBUG
106 	if (prefix == NULL) {
107 #endif
108 		if (prefix)
109 			printf("%s ", prefix);
110 		printf("Data abort: '%s' status=%03x address=%08x PC=%08x\n",
111 		    aborts[fault_status & FAULT_TYPE_MASK],
112 		    fault_status & 0xfff, fault_address, fault_pc);
113 #ifndef DEBUG
114 	}
115 #endif
116 }
117 
118 static __volatile int data_abort_expected;
119 static __volatile int data_abort_received;
120 
121 int
122 badaddr_read(void *addr, size_t size, void *rptr)
123 {
124 	u_long rcpt;
125 	int rv;
126 
127 	/* Tell the Data Abort handler that we're expecting one. */
128 	data_abort_received = 0;
129 	data_abort_expected = 1;
130 
131 	cpu_drain_writebuf();
132 
133 	/* Read from the test address. */
134 	switch (size) {
135 	case sizeof(uint8_t):
136 		__asm __volatile("ldrb %0, [%1]"
137 			: "=r" (rcpt)
138 			: "r" (addr));
139 		break;
140 
141 	case sizeof(uint16_t):
142 		__asm __volatile("ldrh %0, [%1]"
143 			: "=r" (rcpt)
144 			: "r" (addr));
145 		break;
146 
147 	case sizeof(uint32_t):
148 		__asm __volatile("ldr %0, [%1]"
149 			: "=r" (rcpt)
150 			: "r" (addr));
151 		break;
152 
153 	default:
154 		data_abort_expected = 0;
155 		panic("badaddr: invalid size (%lu)\n", (u_long) size);
156 	}
157 
158 	/* Disallow further Data Aborts. */
159 	data_abort_expected = 0;
160 
161 	rv = data_abort_received;
162 	data_abort_received = 0;
163 
164 	/* Copy the data back if no fault occurred. */
165 	if (rptr != NULL && rv == 0) {
166 		switch (size) {
167 		case sizeof(uint8_t):
168 			*(uint8_t *) rptr = rcpt;
169 			break;
170 
171 		case sizeof(uint16_t):
172 			*(uint16_t *) rptr = rcpt;
173 			break;
174 
175 		case sizeof(uint32_t):
176 			*(uint32_t *) rptr = rcpt;
177 			break;
178 		}
179 	}
180 
181 	/* Return true if the address was invalid. */
182 	return (rv);
183 }
184 
185 /*
186  * void data_abort_handler(trapframe_t *frame)
187  *
188  * Abort handler called when read/write occurs at an address of
189  * a non existent or restricted (access permissions) memory page.
190  * We first need to identify the type of page fault.
191  */
192 
193 #define TRAP_CODE ((fault_status & 0x0f) | (fault_address & 0xfffffff0))
194 
195 void
196 data_abort_handler(frame)
197 	trapframe_t *frame;
198 {
199 	struct proc *p;
200 	struct pcb *pcb;
201 	u_int fault_address;
202 	u_int fault_status;
203 	u_int fault_pc;
204 	u_int fault_instruction;
205 	int fault_code;
206 	int user;
207 	int error;
208 	void *onfault;
209 
210 	/*
211 	 * If we were expecting a Data Abort, signal that we got
212 	 * one, adjust the PC to skip the faulting insn, and
213 	 * return.
214 	 */
215 	if (data_abort_expected) {
216 		data_abort_received = 1;
217 		frame->tf_pc += INSN_SIZE;
218 		return;
219 	}
220 
221 	/*
222 	 * Must get fault address and status from the CPU before
223 	 * re-enabling interrupts.  (Interrupt handlers may take
224 	 * R/M emulation faults.)
225 	 */
226 	fault_address = cpu_faultaddress();
227 	fault_status = cpu_faultstatus();
228 	fault_pc = frame->tf_pc;
229 
230 	/*
231 	 * Enable IRQ's (disabled by CPU on abort) if trapframe
232 	 * shows they were enabled.
233 	 */
234 	if (!(frame->tf_spsr & I32_bit))
235 		enable_interrupts(I32_bit);
236 
237 #ifdef DEBUG
238 	if ((GetCPSR() & PSR_MODE) != PSR_SVC32_MODE)
239 		panic("data_abort_handler: not in SVC32 mode");
240 #endif
241 
242 	/* Update vmmeter statistics */
243 	uvmexp.traps++;
244 
245 	/* Extract the fault code from the fault status */
246 	fault_code = fault_status & FAULT_TYPE_MASK;
247 
248 	/* Get the current proc structure or proc0 if there is none */
249 	if ((p = curproc) == NULL)
250 		p = &proc0;
251 
252 	/*
253 	 * can't use curpcb, as it might be NULL; and we have p in
254 	 * a register anyway
255 	 */
256 	pcb = &p->p_addr->u_pcb;
257 
258 	/* fusubailout is used by [fs]uswintr to avoid page faulting */
259 	if (pcb->pcb_onfault
260 	    && ((fault_code != FAULT_TRANS_S && fault_code != FAULT_TRANS_P &&
261 		 fault_code != FAULT_PERM_S && fault_code != FAULT_PERM_P)
262 	        || pcb->pcb_onfault == fusubailout)) {
263 
264 copyfault:
265 #ifdef DEBUG
266 		printf("Using pcb_onfault=%p addr=%08x st=%08x p=%p\n",
267 		    pcb->pcb_onfault, fault_address, fault_status, p);
268 #endif
269 		frame->tf_pc = (u_int)pcb->pcb_onfault;
270 		if ((frame->tf_spsr & PSR_MODE) == PSR_USR32_MODE)
271 			panic("Yikes pcb_onfault=%p during USR mode fault\n",
272 			    pcb->pcb_onfault);
273 		return;
274 	}
275 
276 	/* More debug stuff */
277 
278 	fault_instruction = ReadWord(fault_pc);
279 
280 #ifdef PMAP_DEBUG
281 	if (pmap_debug_level >= 0) {
282 		report_abort(NULL, fault_status, fault_address, fault_pc);
283 		printf("Instruction @V%08x = %08x\n",
284 		    fault_pc, fault_instruction);
285 	}
286 #endif
287 
288 	/* Call the cpu specific abort fixup routine */
289 	error = cpu_dataabt_fixup(frame);
290 	if (error == ABORT_FIXUP_RETURN)
291 		return;
292 	if (error == ABORT_FIXUP_FAILED) {
293 		printf("pc = 0x%08x, insn = ", fault_pc);
294 		disassemble(fault_pc);
295 		panic("data abort fixup failed\n");
296 	}
297 
298 #ifdef PMAP_DEBUG
299 	if (pmap_debug_level >= 0)
300 		printf("fault in process %p\n", p);
301 #endif
302 
303 #ifdef DEBUG
304 	/* Is this needed ? */
305 	if (pcb != curpcb) {
306 		printf("data_abort: Alert ! pcb(%p) != curpcb(%p)\n",
307 		    pcb, curpcb);
308 		printf("data_abort: Alert ! proc(%p), curproc(%p)\n",
309 		    p, curproc);
310 	}
311 #endif	/* DEBUG */
312 
313 	/* Were we in user mode when the abort occurred ? */
314 	if ((frame->tf_spsr & PSR_MODE) == PSR_USR32_MODE) {
315 		/*
316 		 * Note that the fault was from USR mode.
317 		 */
318 		user = 1;
319 		p->p_addr->u_pcb.pcb_tf = frame;
320 	} else
321 		user = 0;
322 
323 	/* Now act on the fault type */
324 	switch (fault_code) {
325 	case FAULT_WRTBUF_0:              /* Write Buffer Fault */
326 	case FAULT_WRTBUF_1:              /* Write Buffer Fault */
327 		/* If this happens forget it no point in continuing */
328 
329 		/* FALLTHROUGH */
330 
331 	case FAULT_ALIGN_0:              /* Alignment Fault */
332 	case FAULT_ALIGN_1:              /* Alignment Fault */
333 		/*
334 		 * Really this should just kill the process.
335 		 * Alignment faults are turned off in the kernel
336 		 * in order to get better performance from shorts with
337 		 * GCC so an alignment fault means somebody has played
338 		 * with the control register in the CPU. Might as well
339 		 * panic as the kernel was not compiled for aligned accesses.
340 		 */
341 
342 		/* FALLTHROUGH */
343 
344 	case FAULT_BUSERR_0:              /* Bus Error LF Section */
345 	case FAULT_BUSERR_1:              /* Bus Error Page */
346 	case FAULT_BUSERR_2:              /* Bus Error Section */
347 	case FAULT_BUSERR_3:              /* Bus Error Page */
348 		/* What will accutally cause a bus error ? */
349 		/* Real bus errors are not a process problem but hardware */
350 
351 		/* FALLTHROUGH */
352 
353 	case FAULT_DOMAIN_S:              /* Section Domain Error Fault */
354 	case FAULT_DOMAIN_P:              /* Page Domain Error Fault*/
355 		/*
356 		 * Right well we dont use domains, everything is
357 		 * always a client and thus subject to access permissions.
358 		 * If we get a domain error then we have corrupts PTE's
359 		 * so we might as well die !
360 		 * I suppose eventually this should just kill the process
361 		 * who owns the PTE's but if this happens it implies a
362 		 * kernel problem.
363 		 */
364 
365 		/* FALLTHROUGH */
366 
367 	case FAULT_BUSTRNL1:              /* Bus Error Trans L1 Fault */
368 	case FAULT_BUSTRNL2:              /* Bus Error Trans L2 Fault */
369 		/*
370 		 * These faults imply that the PTE is corrupt.
371 		 * Likely to be a kernel fault so we had better stop.
372 		 */
373 
374 		/* FALLTHROUGH */
375 
376 	default :
377 		/* Are there any combinations I have missed ? */
378 		report_abort(NULL, fault_status, fault_address, fault_pc);
379 
380 	we_re_toast:
381 		/*
382 		 * Were are dead, try and provide some debug
383 		 * information before dying.
384 		 */
385 #ifdef DDB
386 		printf("Unhandled trap (frame = %p)\n", frame);
387 		report_abort(NULL, fault_status, fault_address, fault_pc);
388 		kdb_trap(-1, frame);
389 		return;
390 #else
391 		panic("Unhandled trap (frame = %p)", frame);
392 #endif	/* DDB */
393 
394 	case FAULT_TRANS_P:              /* Page Translation Fault */
395 	case FAULT_PERM_P:		 /* Page Permission Fault */
396 	case FAULT_TRANS_S:              /* Section Translation Fault */
397 	case FAULT_PERM_S:		 /* Section Permission Fault */
398 	/*
399 	 * Page/section translation/permission fault -- need to fault in
400 	 * the page and possibly the page table page.
401 	 */
402 	{
403 		register vaddr_t va;
404 		register struct vmspace *vm = p->p_vmspace;
405 		register struct vm_map *map;
406 		int rv;
407 		vm_prot_t ftype;
408 		extern struct vm_map *kernel_map;
409 
410 		va = trunc_page((vaddr_t)fault_address);
411 
412 #ifdef PMAP_DEBUG
413 		if (pmap_debug_level >= 0)
414 			printf("page fault: addr=V%08lx ", va);
415 #endif
416 
417 		/*
418 		 * It is only a kernel address space fault iff:
419 		 *	1. user == 0  and
420 		 *	2. pcb_onfault not set or
421 		 *	3. pcb_onfault set but supervisor space fault
422 		 * The last can occur during an exec() copyin where the
423 		 * argument space is lazy-allocated.
424 		 */
425 		if (!user &&
426 		    (va >= VM_MIN_KERNEL_ADDRESS || va < VM_MIN_ADDRESS)) {
427 			/* Was the fault due to the FPE/IPKDB ? */
428 			if ((frame->tf_spsr & PSR_MODE) == PSR_UND32_MODE) {
429 				report_abort("UND32", fault_status,
430 				    fault_address, fault_pc);
431 				trapsignal(p, SIGSEGV, TRAP_CODE);
432 
433 				/*
434 				 * Force exit via userret()
435 				 * This is necessary as the FPE is an extension
436 				 * to userland that actually runs in a
437 				 * priveledged mode but uses USR mode
438 				 * permissions for its accesses.
439 				 */
440 				userret(p);
441 				return;
442 			}
443 			map = kernel_map;
444 		} else
445 			map = &vm->vm_map;
446 
447 #ifdef PMAP_DEBUG
448 		if (pmap_debug_level >= 0)
449 			printf("vmmap=%p ", map);
450 #endif
451 
452 		if (map == NULL)
453 			panic("No map for fault address\n");
454 
455 		/*
456 		 * We need to know whether the page should be mapped
457 		 * as R or R/W. The MMU does not give us the info as
458 		 * to whether the fault was caused by a read or a write.
459 		 * This means we need to disassemble the instruction
460 		 * responsible and determine if it was a read or write
461 		 * instruction.
462 		 */
463 		/* STR instruction ? */
464 		if ((fault_instruction & 0x0c100000) == 0x04000000)
465 			ftype = VM_PROT_READ | VM_PROT_WRITE;
466 		/* STM or CDT instruction ? */
467 		else if ((fault_instruction & 0x0a100000) == 0x08000000)
468 			ftype = VM_PROT_READ | VM_PROT_WRITE;
469 		/* STRH, STRSH or STRSB instruction ? */
470 		else if ((fault_instruction & 0x0e100090) == 0x00000090)
471 			ftype = VM_PROT_READ | VM_PROT_WRITE;
472 		/* SWP instruction ? */
473 		else if ((fault_instruction & 0x0fb00ff0) == 0x01000090)
474 			ftype = VM_PROT_READ | VM_PROT_WRITE;
475 		else
476 			ftype = VM_PROT_READ;
477 
478 #ifdef PMAP_DEBUG
479 		if (pmap_debug_level >= 0)
480 			printf("fault protection = %d\n", ftype);
481 #endif
482 
483 		if ((ftype & VM_PROT_WRITE) ?
484 		    pmap_modified_emulation(map->pmap, va) :
485 		    pmap_handled_emulation(map->pmap, va))
486 			goto out;
487 
488 		if (current_intr_depth > 0) {
489 #ifdef DDB
490 			printf("Non-emulated page fault with intr_depth > 0\n");
491 			report_abort(NULL, fault_status, fault_address, fault_pc);
492 			kdb_trap(-1, frame);
493 			return;
494 #else
495 			panic("Fault with intr_depth > 0");
496 #endif	/* DDB */
497 		}
498 
499 		onfault = pcb->pcb_onfault;
500 		pcb->pcb_onfault = NULL;
501 		rv = uvm_fault(map, va, 0, ftype);
502 		pcb->pcb_onfault = onfault;
503 		if (rv == 0)
504 			goto out;
505 
506 		if (user == 0) {
507 			if (pcb->pcb_onfault)
508 				goto copyfault;
509 			printf("[u]vm_fault(%p, %lx, %x, 0) -> %x\n",
510 			    map, va, ftype, rv);
511 			goto we_re_toast;
512 		}
513 
514 		report_abort("", fault_status, fault_address, fault_pc);
515 		if (rv == ENOMEM) {
516 			printf("UVM: pid %d (%s), uid %d killed: "
517 			       "out of swap\n", p->p_pid, p->p_comm,
518 			       p->p_cred && p->p_ucred ?
519 			       p->p_ucred->cr_uid : -1);
520 			trapsignal(p, SIGKILL, TRAP_CODE);
521 		} else
522 			trapsignal(p, SIGSEGV, TRAP_CODE);
523 		break;
524 	}
525 	}
526 
527 out:
528 	/* Call userret() if it was a USR mode fault */
529 	if (user)
530 		userret(p);
531 }
532 
533 
534 /*
535  * void prefetch_abort_handler(trapframe_t *frame)
536  *
537  * Abort handler called when instruction execution occurs at
538  * a non existent or restricted (access permissions) memory page.
539  * If the address is invalid and we were in SVC mode then panic as
540  * the kernel should never prefetch abort.
541  * If the address is invalid and the page is mapped then the user process
542  * does no have read permission so send it a signal.
543  * Otherwise fault the page in and try again.
544  */
545 
546 extern int kernel_debug;
547 
548 void
549 prefetch_abort_handler(frame)
550 	trapframe_t *frame;
551 {
552 	register u_int fault_pc;
553 	register struct proc *p;
554 	register struct pcb *pcb;
555 	u_int fault_instruction;
556 	pt_entry_t *pte;
557 	int error;
558 
559 	/*
560 	 * Enable IRQ's (disabled by the abort) This always comes
561 	 * from user mode so we know interrupts were not disabled.
562 	 * But we check anyway.
563 	 */
564 	if (!(frame->tf_spsr & I32_bit))
565 		enable_interrupts(I32_bit);
566 
567 #ifdef DEBUG
568 	if ((GetCPSR() & PSR_MODE) != PSR_SVC32_MODE)
569 		panic("prefetch_abort_handler: not in SVC32 mode");
570 #endif
571 
572 	/* Update vmmeter statistics */
573 	uvmexp.traps++;
574 
575 	/* Call the cpu specific abort fixup routine */
576 	error = cpu_prefetchabt_fixup(frame);
577 	if (error == ABORT_FIXUP_RETURN)
578 		return;
579 	if (error == ABORT_FIXUP_FAILED)
580 		panic("prefetch abort fixup failed\n");
581 
582 	/* Get the current proc structure or proc0 if there is none */
583 	if ((p = curproc) == 0) {
584 		p = &proc0;
585 #ifdef DEBUG
586 		printf("Prefetch abort with curproc == 0\n");
587 #endif
588 	}
589 
590 #ifdef PMAP_DEBUG
591 	if (pmap_debug_level >= 0)
592 		printf("prefetch fault in process %p %s\n", p, p->p_comm);
593 #endif
594 	/*
595 	 * can't use curpcb, as it might be NULL; and we have p in a
596 	 * register anyway
597 	 */
598 	pcb = &p->p_addr->u_pcb;
599 	if (pcb == 0)
600 		panic("prefetch_abort_handler: no pcb ... we're toast !\n");
601 
602 #ifdef DEBUG
603 	if (pcb != curpcb) {
604 		printf("data_abort: Alert ! pcb(%p) != curpcb(%p)\n",
605 		    pcb, curpcb);
606 		printf("data_abort: Alert ! proc(%p), curproc(%p)\n",
607 		    p, curproc);
608 	}
609 #endif	/* DEBUG */
610 
611 	/* Get fault address */
612 	fault_pc = frame->tf_pc;
613 
614 	/* Was the prefectch abort from USR32 mode ? */
615 	if ((frame->tf_spsr & PSR_MODE) == PSR_USR32_MODE) {
616 		p->p_addr->u_pcb.pcb_tf = frame;
617 	} else {
618 		/*
619 		 * All the kernel code pages are loaded at boot time
620 		 * and do not get paged
621 		 */
622 	        panic("Prefetch abort in non-USR mode (frame=%p PC=0x%08x)\n",
623 	            frame, fault_pc);
624 	}
625 
626 #ifdef PMAP_DEBUG
627 	if (pmap_debug_level >= 0)
628 		printf("prefetch_abort: PC = %08x\n", fault_pc);
629 #endif
630 	/* Ok validate the address, can only execute in USER space */
631 	if (fault_pc < VM_MIN_ADDRESS || fault_pc >= VM_MAXUSER_ADDRESS) {
632 #ifdef DEBUG
633 		printf("prefetch: pc (%08x) not in user process space\n",
634 		    fault_pc);
635 #endif
636 		trapsignal(p, SIGSEGV, fault_pc);
637 		userret(p);
638 		return;
639 	}
640 
641 	/* Is the page already mapped ? */
642 	/* This is debugging for rev K SA110 silicon */
643 	pte = pmap_pte(p->p_vmspace->vm_map.pmap, (vaddr_t)fault_pc);
644 	if (pte && *pte != 0) {
645 		if (kernel_debug & 1) {
646 			printf("prefetch_abort: page is already mapped - pte=%p *pte=%08x\n",
647 			    pte, *pte);
648 			printf("prefetch_abort: pc=%08x proc=%p process=%s\n", fault_pc, p, p->p_comm);
649 			printf("prefetch_abort: far=%08x fs=%x\n", cpu_faultaddress(), cpu_faultstatus());
650 			printf("prefetch_abort: trapframe=%08x\n", (u_int)frame);
651 		}
652 #ifdef DDB
653 		if (kernel_debug & 2)
654 			Debugger();
655 #endif
656 	}
657 
658 	/* Ok read the fault address. This will fault the page in for us */
659 	if (fetchuserword(fault_pc, &fault_instruction) != 0) {
660 #ifdef DEBUG
661 		printf("prefetch: faultin failed for address %08x\n",
662 		    fault_pc);
663 #endif
664 		trapsignal(p, SIGSEGV, fault_pc);
665 	} else {
666 
667 #ifdef DIAGNOSTIC
668 		/* More debug stuff */
669 
670 #ifdef PMAP_DEBUG
671 		if (pmap_debug_level >= 0) {
672 			printf("Instruction @V%08x = %08x\n", fault_pc,
673 			    fault_instruction);
674 			disassemble(fault_pc);
675 			printf("return addr=%08x", frame->tf_pc);
676 			pte = pmap_pte(p->p_vmspace->vm_map.pmap,
677 			    (vaddr_t)fault_pc);
678 			if (pte)
679 				printf(" pte=%p *pte=%08x\n", pte, *pte);
680 			else
681 				printf("\n");
682 
683 		}
684 #endif	/* PMAP_DEBUG */
685 #endif	/* DIAGNOSTIC */
686 	}
687 
688 	userret(p);
689 }
690 
691 int
692 cowfault(va)
693 	vaddr_t va;
694 {
695 	struct vmspace *vm;
696 	int error;
697 
698 	if (va >= VM_MAXUSER_ADDRESS)
699 		return (EFAULT);
700 
701 	/* uvm_fault can't be called from within an interrupt */
702 	KASSERT(current_intr_depth == 0);
703 
704 	vm = curproc->p_vmspace;
705 	error = uvm_fault(&vm->vm_map, va, 0, VM_PROT_READ | VM_PROT_WRITE);
706 	return error;
707 }
708 
709 /* End of fault.c */
710