xref: /netbsd-src/sys/arch/powerpc/ibm4xx/trap.c (revision dd3ee07da436799d8de85f3055253118b76bf345)
1 /*	$NetBSD: trap.c,v 1.87 2022/05/30 14:09:01 rin 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 #define	__UFETCHSTORE_PRIVATE
70 
71 #include <sys/cdefs.h>
72 __KERNEL_RCSID(0, "$NetBSD: trap.c,v 1.87 2022/05/30 14:09:01 rin Exp $");
73 
74 #ifdef _KERNEL_OPT
75 #include "opt_ddb.h"
76 #include "opt_kgdb.h"
77 #include "opt_ppcarch.h"
78 #include "opt_ppcopts.h"
79 #endif
80 
81 #include <sys/param.h>
82 #include <sys/cpu.h>
83 #include <sys/kauth.h>
84 #include <sys/proc.h>
85 #include <sys/ptrace.h>
86 #include <sys/reboot.h>
87 #include <sys/syscall.h>
88 #include <sys/systm.h>
89 
90 #if defined(KGDB)
91 #include <sys/kgdb.h>
92 #endif
93 
94 #include <uvm/uvm_extern.h>
95 
96 #include <dev/cons.h>
97 
98 #include <machine/fpu.h>
99 #include <machine/frame.h>
100 #include <machine/pcb.h>
101 #include <machine/psl.h>
102 #include <machine/trap.h>
103 
104 #include <powerpc/db_machdep.h>
105 #include <powerpc/spr.h>
106 #include <powerpc/userret.h>
107 
108 #include <powerpc/ibm4xx/cpu.h>
109 #include <powerpc/ibm4xx/pmap.h>
110 #include <powerpc/ibm4xx/spr.h>
111 #include <powerpc/ibm4xx/tlb.h>
112 
113 #include <powerpc/fpu/fpu_extern.h>
114 
115 /* These definitions should probably be somewhere else			XXX */
116 #define	FIRSTARG	3		/* first argument is in reg 3 */
117 #define	NARGREG		8		/* 8 args are in registers */
118 #define	MOREARGS(sp)	((void *)((int)(sp) + 8)) /* more args go here */
119 
120 void trap(struct trapframe *);	/* Called from locore / trap_subr */
121 #if 0
122 /* Not currently used nor exposed externally in any header file */
123 int badaddr(void *, size_t);
124 int badaddr_read(void *, size_t, int *);
125 #endif
126 int ctx_setup(int, int);
127 
128 #ifndef PPC_NO_UNALIGNED
129 static bool fix_unaligned(struct trapframe *, ksiginfo_t *);
130 #endif
131 
132 #ifdef DEBUG
133 #define TDB_ALL	0x1
134 int trapdebug = /* TDB_ALL */ 0;
135 #define	DBPRINTF(x, y)	if (trapdebug & (x)) printf y
136 #else
137 #define DBPRINTF(x, y)
138 #endif
139 
140 void
141 trap(struct trapframe *tf)
142 {
143 	struct lwp *l = curlwp;
144 	struct proc *p = l->l_proc;
145 	struct pcb *pcb;
146 	int type = tf->tf_exc;
147 	int ftype, rv;
148 	ksiginfo_t ksi;
149 
150 	KASSERT(l->l_stat == LSONPROC);
151 
152 	if (tf->tf_srr1 & PSL_PR) {
153 		LWP_CACHE_CREDS(l, p);
154 		type |= EXC_USER;
155 	}
156 
157 	ftype = VM_PROT_READ;
158 
159 	DBPRINTF(TDB_ALL, ("trap(%x) at %lx from frame %p &frame %p\n",
160 	    type, tf->tf_srr0, tf, &tf));
161 
162 	switch (type) {
163 	case EXC_DEBUG|EXC_USER:
164 		/* We don't use hardware breakpoints for userland. */
165 		goto brain_damage;
166 
167 	case EXC_TRC|EXC_USER:
168 		KSI_INIT_TRAP(&ksi);
169 		ksi.ksi_signo = SIGTRAP;
170 		ksi.ksi_trap = EXC_TRC;
171 		ksi.ksi_addr = (void *)tf->tf_srr0;
172 		trapsignal(l, &ksi);
173 		break;
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;
182 
183 			pcb = lwp_getpcb(l);
184 			fb = pcb->pcb_onfault;
185 
186 			if (curcpu()->ci_idepth >= 0) {
187 				rv = EFAULT;
188 				goto out;
189 			}
190 
191 			va = tf->tf_dear;
192 			if (tf->tf_pid == KERNEL_PID) {
193 				map = kernel_map;
194 			} else {
195 				map = &p->p_vmspace->vm_map;
196 			}
197 
198 			if (tf->tf_esr & (ESR_DST|ESR_DIZ))
199 				ftype = VM_PROT_WRITE;
200 
201 			DBPRINTF(TDB_ALL,
202 			    ("trap(EXC_DSI) at %lx %s fault on %p esr %x\n",
203 			    tf->tf_srr0,
204 			    (ftype & VM_PROT_WRITE) ? "write" : "read",
205 			    (void *)va, tf->tf_esr));
206 
207 			pcb->pcb_onfault = NULL;
208 			rv = uvm_fault(map, trunc_page(va), ftype);
209 			pcb->pcb_onfault = fb;
210 			if (rv == 0)
211 				return;
212 out:
213 			if (fb != NULL) {
214 				tf->tf_pid = KERNEL_PID;
215 				tf->tf_srr0 = fb->fb_pc;
216 				tf->tf_srr1 |= PSL_IR; /* Re-enable IMMU */
217 				tf->tf_cr = fb->fb_cr;
218 				tf->tf_fixreg[1] = fb->fb_sp;
219 				tf->tf_fixreg[2] = fb->fb_r2;
220 				tf->tf_fixreg[3] = rv;
221 				memcpy(&tf->tf_fixreg[13], fb->fb_fixreg,
222 				    sizeof(fb->fb_fixreg));
223 				return;
224 			}
225 		}
226 		goto brain_damage;
227 
228 	case EXC_DSI|EXC_USER:
229 		/* FALLTHROUGH */
230 	case EXC_DTMISS|EXC_USER:
231 		if (tf->tf_esr & (ESR_DST|ESR_DIZ))
232 			ftype = VM_PROT_WRITE;
233 
234 		DBPRINTF(TDB_ALL,
235 		    ("trap(EXC_DSI|EXC_USER) at %lx %s fault on %lx %x\n",
236 		    tf->tf_srr0, (ftype & VM_PROT_WRITE) ? "write" : "read",
237 		    tf->tf_dear, tf->tf_esr));
238 		KASSERT(l == curlwp && (l->l_stat == LSONPROC));
239 //		KASSERT(curpcb->pcb_onfault == NULL);
240 		rv = uvm_fault(&p->p_vmspace->vm_map, trunc_page(tf->tf_dear),
241 		    ftype);
242 		if (rv == 0) {
243 			break;
244 		}
245 		KSI_INIT_TRAP(&ksi);
246 		ksi.ksi_trap = EXC_DSI;
247 		ksi.ksi_addr = (void *)tf->tf_dear;
248 vm_signal:
249 		switch (rv) {
250 		case EINVAL:
251 			ksi.ksi_signo = SIGBUS;
252 			ksi.ksi_code = BUS_ADRERR;
253 			break;
254 		case EACCES:
255 			ksi.ksi_signo = SIGSEGV;
256 			ksi.ksi_code = SEGV_ACCERR;
257 			break;
258 		case ENOMEM:
259 			ksi.ksi_signo = SIGKILL;
260 			printf("UVM: pid %d.%d (%s), uid %d killed: "
261 			       "out of swap\n", p->p_pid, l->l_lid, p->p_comm,
262 			       l->l_cred ? kauth_cred_geteuid(l->l_cred) : -1);
263 			break;
264 		default:
265 			ksi.ksi_signo = SIGSEGV;
266 			ksi.ksi_code = SEGV_MAPERR;
267 			break;
268 		}
269 		trapsignal(l, &ksi);
270 		break;
271 
272 	case EXC_ITMISS|EXC_USER:
273 	case EXC_ISI|EXC_USER:
274 		ftype = VM_PROT_EXECUTE;
275 		DBPRINTF(TDB_ALL,
276 		    ("trap(EXC_ISI|EXC_USER) at %lx execute fault tf %p\n",
277 		    tf->tf_srr0, tf));
278 //		KASSERT(curpcb->pcb_onfault == NULL);
279 		rv = uvm_fault(&p->p_vmspace->vm_map, trunc_page(tf->tf_srr0),
280 		    ftype);
281 		if (rv == 0) {
282 			break;
283 		}
284 isi:
285 		KSI_INIT_TRAP(&ksi);
286 		ksi.ksi_trap = EXC_ISI;
287 		ksi.ksi_addr = (void *)tf->tf_srr0;
288 		goto vm_signal;
289 		break;
290 
291 	case EXC_AST|EXC_USER:
292 		cpu_ast(l, curcpu());
293 		break;
294 
295 	case EXC_ALI|EXC_USER:
296 		if (fix_unaligned(tf, &ksi))
297 			trapsignal(l, &ksi);
298 		break;
299 
300 	case EXC_PGM|EXC_USER:
301 		curcpu()->ci_data.cpu_ntrap++;
302 
303 		KSI_INIT_TRAP(&ksi);
304 		ksi.ksi_trap = EXC_PGM;
305 		ksi.ksi_addr = (void *)tf->tf_srr0;
306 
307 		if (tf->tf_esr & ESR_PTR) {
308 			vaddr_t va;
309 sigtrap:
310 			va = (vaddr_t)tf->tf_srr0;
311 			/*
312 		 	 * Restore original instruction and clear BP.
313 		 	 */
314 			if (p->p_md.md_ss_addr[0] == va ||
315 			    p->p_md.md_ss_addr[1] == va) {
316 				rv = ppc_sstep(l, 0);
317 				if (rv != 0)
318 					goto vm_signal;
319 				ksi.ksi_code = TRAP_TRACE;
320 			} else
321 				ksi.ksi_code = TRAP_BRKPT;
322 			if (p->p_raslist != NULL &&
323 			    ras_lookup(p, (void *)va) != (void *)-1) {
324 				tf->tf_srr0 += (ksi.ksi_code == TRAP_TRACE) ?
325 				    0 : 4;
326 				break;
327 			}
328 			ksi.ksi_signo = SIGTRAP;
329 		} else if (tf->tf_esr & ESR_PPR) {
330 			uint32_t opcode;
331 
332 			rv = copyin((void *)tf->tf_srr0, &opcode,
333 			    sizeof(opcode));
334 			if (rv)
335 				goto isi;
336 			if (emulate_mxmsr(l, tf, opcode)) {
337 				tf->tf_srr0 += 4;
338 				break;
339 			}
340 
341 			ksi.ksi_code = ILL_PRVOPC;
342 			ksi.ksi_signo = SIGILL;
343 		} else {
344 			pcb = lwp_getpcb(l);
345 
346 			if (__predict_false(!fpu_used_p(l))) {
347 				memset(&pcb->pcb_fpu, 0, sizeof(pcb->pcb_fpu));
348 				fpu_mark_used(l);
349 			}
350 
351 			if (fpu_emulate(tf, &pcb->pcb_fpu, &ksi)) {
352 				if (ksi.ksi_signo == 0)	/* was emulated */
353 					break;
354 				else if (ksi.ksi_signo == SIGTRAP)
355 					goto sigtrap;	/* XXX H/W bug? */
356 			} else {
357 				ksi.ksi_code = ILL_ILLOPC;
358 				ksi.ksi_signo = SIGILL;
359 			}
360 		}
361 
362 		trapsignal(l, &ksi);
363 		break;
364 
365 	case EXC_MCHK:
366 		{
367 			struct faultbuf *fb;
368 
369 			pcb = lwp_getpcb(l);
370 			if ((fb = pcb->pcb_onfault) != NULL) {
371 				tf->tf_pid = KERNEL_PID;
372 				tf->tf_srr0 = fb->fb_pc;
373 				tf->tf_srr1 |= PSL_IR; /* Re-enable IMMU */
374 				tf->tf_fixreg[1] = fb->fb_sp;
375 				tf->tf_fixreg[2] = fb->fb_r2;
376 				tf->tf_fixreg[3] = 1; /* Return TRUE */
377 				tf->tf_cr = fb->fb_cr;
378 				memcpy(&tf->tf_fixreg[13], fb->fb_fixreg,
379 				    sizeof(fb->fb_fixreg));
380 				return;
381 			}
382 		}
383 		goto brain_damage;
384 
385 	default:
386 brain_damage:
387 		printf("trap type 0x%x at 0x%lx\n", type, tf->tf_srr0);
388 #if defined(DDB) || defined(KGDB)
389 		if (kdb_trap(type, tf))
390 			return;
391 #endif
392 #ifdef TRAP_PANICWAIT
393 		printf("Press a key to panic.\n");
394 		cngetc();
395 #endif
396 		panic("trap");
397 	}
398 
399 	/* Invoke powerpc userret code */
400 	userret(l, tf);
401 }
402 
403 int
404 ctx_setup(int ctx, int srr1)
405 {
406 	volatile struct pmap *pm;
407 
408 	/* Update PID if we're returning to user mode. */
409 	if (srr1 & PSL_PR) {
410 		pm = curproc->p_vmspace->vm_map.pmap;
411 		if (!pm->pm_ctx) {
412 			ctx_alloc(__UNVOLATILE(pm));
413 		}
414 		ctx = pm->pm_ctx;
415 	}
416 	else if (!ctx) {
417 		ctx = KERNEL_PID;
418 	}
419 	return (ctx);
420 }
421 
422 /*
423  * Used by copyin()/copyout()
424  */
425 extern vaddr_t vmaprange(struct proc *, vaddr_t, vsize_t, int);
426 extern void vunmaprange(vaddr_t, vsize_t);
427 static int bigcopyin(const void *, void *, size_t );
428 static int bigcopyout(const void *, void *, size_t );
429 
430 int
431 copyin(const void *udaddr, void *kaddr, size_t len)
432 {
433 	struct pmap *pm = curproc->p_vmspace->vm_map.pmap;
434 	int rv, msr, pid, tmp, ctx, count = 0;
435 	struct faultbuf env;
436 
437 	/* For bigger buffers use the faster copy */
438 	if (len > 1024)
439 		return (bigcopyin(udaddr, kaddr, len));
440 
441 	if ((rv = setfault(&env))) {
442 		curpcb->pcb_onfault = NULL;
443 		return rv;
444 	}
445 
446 	if (!(ctx = pm->pm_ctx)) {
447 		/* No context -- assign it one */
448 		ctx_alloc(pm);
449 		ctx = pm->pm_ctx;
450 	}
451 
452 	__asm volatile(
453 		"   mfmsr %[msr];"		/* Save MSR */
454 		"   li %[pid],0x20;"
455 		"   andc %[pid],%[msr],%[pid]; mtmsr %[pid];" /* Disable IMMU */
456 		"   isync;"
457 		"   mfpid %[pid];"		/* Save old PID */
458 
459 		"   srwi. %[count],%[len],0x2;"	/* How many words? */
460 		"   beq- 2f;"			/* No words. Go do bytes */
461 		"   mtctr %[count];"
462 		"1: mtpid %[ctx]; isync;"
463 #ifdef PPC_IBM403
464 		"   lswi %[tmp],%[udaddr],4;"	/* Load user word */
465 #else
466 		"   lwz %[tmp],0(%[udaddr]);"
467 #endif
468 		"   addi %[udaddr],%[udaddr],0x4;" /* next udaddr word */
469 		"   sync;"
470 		"   mtpid %[pid]; isync;"
471 #ifdef PPC_IBM403
472 		"   stswi %[tmp],%[kaddr],4;"	/* Store kernel word */
473 #else
474 		"   stw %[tmp],0(%[kaddr]);"
475 #endif
476 		"   dcbst 0,%[kaddr];"		/* flush cache */
477 		"   addi %[kaddr],%[kaddr],0x4;" /* next udaddr word */
478 		"   sync;"
479 		"   bdnz 1b;"			/* repeat */
480 
481 		"2: andi. %[count],%[len],0x3;"	/* How many remaining bytes? */
482 		"   addi %[count],%[count],0x1;"
483 		"   mtctr %[count];"
484 		"3: bdz 10f;"			/* while count */
485 		"   mtpid %[ctx]; isync;"
486 		"   lbz %[tmp],0(%[udaddr]);"	/* Load user byte */
487 		"   addi %[udaddr],%[udaddr],0x1;" /* next udaddr byte */
488 		"   sync;"
489 		"   mtpid %[pid]; isync;"
490 		"   stb %[tmp],0(%[kaddr]);"	/* Store kernel byte */
491 		"   dcbst 0,%[kaddr];"		/* flush cache */
492 		"   addi %[kaddr],%[kaddr],0x1;"
493 		"   sync;"
494 		"   b 3b;"
495 		"10:mtpid %[pid]; mtmsr %[msr]; isync;"
496 						/* Restore PID and MSR */
497 		: [msr] "=&r" (msr), [pid] "=&r" (pid), [tmp] "=&r" (tmp)
498 		: [udaddr] "b" (udaddr), [ctx] "b" (ctx), [kaddr] "b" (kaddr),
499 		  [len] "b" (len), [count] "b" (count));
500 
501 	curpcb->pcb_onfault = NULL;
502 	return 0;
503 }
504 
505 static int
506 bigcopyin(const void *udaddr, void *kaddr, size_t len)
507 {
508 	const char *up;
509 	char *kp = kaddr;
510 	struct lwp *l = curlwp;
511 	struct proc *p;
512 	struct faultbuf env;
513 	int error;
514 
515 	p = l->l_proc;
516 
517 	/*
518 	 * Stolen from physio():
519 	 */
520 	error = uvm_vslock(p->p_vmspace, __UNCONST(udaddr), len, VM_PROT_READ);
521 	if (error) {
522 		return error;
523 	}
524 	up = (char *)vmaprange(p, (vaddr_t)udaddr, len, VM_PROT_READ);
525 
526 	if ((error = setfault(&env)) == 0) {
527 		memcpy(kp, up, len);
528 	}
529 
530 	curpcb->pcb_onfault = NULL;
531 	vunmaprange((vaddr_t)up, len);
532 	uvm_vsunlock(p->p_vmspace, __UNCONST(udaddr), len);
533 
534 	return error;
535 }
536 
537 int
538 copyout(const void *kaddr, void *udaddr, size_t len)
539 {
540 	struct pmap *pm = curproc->p_vmspace->vm_map.pmap;
541 	int rv, msr, pid, tmp, ctx, count = 0;
542 	struct faultbuf env;
543 
544 	/* For big copies use more efficient routine */
545 	if (len > 1024)
546 		return (bigcopyout(kaddr, udaddr, len));
547 
548 	if ((rv = setfault(&env))) {
549 		curpcb->pcb_onfault = NULL;
550 		return rv;
551 	}
552 
553 	if (!(ctx = pm->pm_ctx)) {
554 		/* No context -- assign it one */
555 		ctx_alloc(pm);
556 		ctx = pm->pm_ctx;
557 	}
558 
559 	__asm volatile(
560 		"   mfmsr %[msr];"		/* Save MSR */
561 		"   li %[pid],0x20;"
562 		"   andc %[pid],%[msr],%[pid]; mtmsr %[pid];" /* Disable IMMU */
563 		"   isync;"
564 		"   mfpid %[pid];"		/* Save old PID */
565 
566 		"   srwi. %[count],%[len],0x2;"	/* How many words? */
567 		"   beq- 2f;"			/* No words. Go do bytes */
568 		"   mtctr %[count];"
569 		"1: mtpid %[pid]; isync;"
570 #ifdef PPC_IBM403
571 		"   lswi %[tmp],%[kaddr],4;"	/* Load kernel word */
572 #else
573 		"   lwz %[tmp],0(%[kaddr]);"
574 #endif
575 		"   addi %[kaddr],%[kaddr],0x4;" /* next kaddr word */
576 		"   sync;"
577 		"   mtpid %[ctx]; isync;"
578 #ifdef PPC_IBM403
579 		"   stswi %[tmp],%[udaddr],4;"	/* Store user word */
580 #else
581 		"   stw %[tmp],0(%[udaddr]);"
582 #endif
583 		"   dcbst 0,%[udaddr];"		/* flush cache */
584 		"   addi %[udaddr],%[udaddr],0x4;" /* next udaddr word */
585 		"   sync;"
586 		"   bdnz 1b;"			/* repeat */
587 
588 		"2: andi. %[count],%[len],0x3;"	/* How many remaining bytes? */
589 		"   addi %[count],%[count],0x1;"
590 		"   mtctr %[count];"
591 		"3: bdz  10f;"			/* while count */
592 		"   mtpid %[pid]; isync;"
593 		"   lbz %[tmp],0(%[kaddr]);"	/* Load kernel byte */
594 		"   addi %[kaddr],%[kaddr],0x1;" /* next kaddr byte */
595 		"   sync;"
596 		"   mtpid %[ctx]; isync;"
597 		"   stb %[tmp],0(%[udaddr]);"	/* Store user byte */
598 		"   dcbst 0,%[udaddr];"		/* flush cache */
599 		"   addi %[udaddr],%[udaddr],0x1;"
600 		"   sync;"
601 		"   b 3b;"
602 		"10:mtpid %[pid]; mtmsr %[msr]; isync;"
603 						/* Restore PID and MSR */
604 		: [msr] "=&r" (msr), [pid] "=&r" (pid), [tmp] "=&r" (tmp)
605 		: [udaddr] "b" (udaddr), [ctx] "b" (ctx), [kaddr] "b" (kaddr),
606 		  [len] "b" (len), [count] "b" (count));
607 
608 	curpcb->pcb_onfault = NULL;
609 	return 0;
610 }
611 
612 static int
613 bigcopyout(const void *kaddr, void *udaddr, size_t len)
614 {
615 	char *up;
616 	const char *kp = (const char *)kaddr;
617 	struct lwp *l = curlwp;
618 	struct proc *p;
619 	struct faultbuf env;
620 	int error;
621 
622 	p = l->l_proc;
623 
624 	/*
625 	 * Stolen from physio():
626 	 */
627 	error = uvm_vslock(p->p_vmspace, udaddr, len, VM_PROT_WRITE);
628 	if (error) {
629 		return error;
630 	}
631 	up = (char *)vmaprange(p, (vaddr_t)udaddr, len,
632 	    VM_PROT_READ | VM_PROT_WRITE);
633 
634 	if ((error = setfault(&env)) == 0) {
635 		memcpy(up, kp, len);
636 	}
637 
638 	curpcb->pcb_onfault = NULL;
639 	vunmaprange((vaddr_t)up, len);
640 	uvm_vsunlock(p->p_vmspace, udaddr, len);
641 
642 	return error;
643 }
644 
645 /*
646  * kcopy(const void *src, void *dst, size_t len);
647  *
648  * Copy len bytes from src to dst, aborting if we encounter a fatal
649  * page fault.
650  *
651  * kcopy() _must_ save and restore the old fault handler since it is
652  * called by uiomove(), which may be in the path of servicing a non-fatal
653  * page fault.
654  */
655 int
656 kcopy(const void *src, void *dst, size_t len)
657 {
658 	struct faultbuf env, *oldfault;
659 	int rv;
660 
661 	oldfault = curpcb->pcb_onfault;
662 	if ((rv = setfault(&env))) {
663 		curpcb->pcb_onfault = oldfault;
664 		return rv;
665 	}
666 
667 	memcpy(dst, src, len);
668 
669 	curpcb->pcb_onfault = oldfault;
670 	return 0;
671 }
672 
673 #if 0
674 int
675 badaddr(void *addr, size_t size)
676 {
677 
678 	return badaddr_read(addr, size, NULL);
679 }
680 
681 int
682 badaddr_read(void *addr, size_t size, int *rptr)
683 {
684 	struct faultbuf env;
685 	int x;
686 
687 	/* Get rid of any stale machine checks that have been waiting.  */
688 	__asm volatile ("sync; isync");
689 
690 	if (setfault(&env)) {
691 		curpcb->pcb_onfault = NULL;
692 		__asm volatile ("sync");
693 		return 1;
694 	}
695 
696 	__asm volatile ("sync");
697 
698 	switch (size) {
699 	case 1:
700 		x = *(volatile int8_t *)addr;
701 		break;
702 	case 2:
703 		x = *(volatile int16_t *)addr;
704 		break;
705 	case 4:
706 		x = *(volatile int32_t *)addr;
707 		break;
708 	default:
709 		panic("badaddr: invalid size (%d)", size);
710 	}
711 
712 	/* Make sure we took the machine check, if we caused one. */
713 	__asm volatile ("sync; isync");
714 
715 	curpcb->pcb_onfault = NULL;
716 	__asm volatile ("sync");	/* To be sure. */
717 
718 	/* Use the value to avoid reorder. */
719 	if (rptr)
720 		*rptr = x;
721 
722 	return 0;
723 }
724 #endif
725 
726 #ifndef PPC_NO_UNALIGNED
727 static bool
728 fix_unaligned(struct trapframe *tf, ksiginfo_t *ksi)
729 {
730 
731 	KSI_INIT_TRAP(ksi);
732 	ksi->ksi_signo = SIGBUS;
733 	ksi->ksi_trap = EXC_ALI;
734 	ksi->ksi_addr = (void *)tf->tf_dear;
735 	return true;
736 }
737 #endif
738 
739 /*
740  * XXX Extremely lame implementations of _ufetch_* / _ustore_*.  IBM 4xx
741  * experts should make versions that are good.
742  */
743 
744 #define UFETCH(sz)							\
745 int									\
746 _ufetch_ ## sz(const uint ## sz ## _t *uaddr, uint ## sz ## _t *valp)	\
747 {									\
748 	return copyin(uaddr, valp, sizeof(*valp));			\
749 }
750 
751 UFETCH(8)
752 UFETCH(16)
753 UFETCH(32)
754 
755 #define USTORE(sz)							\
756 int									\
757 _ustore_ ## sz(uint ## sz ## _t *uaddr, uint ## sz ## _t val)		\
758 {									\
759 	return copyout(&val, uaddr, sizeof(val));			\
760 }
761 
762 USTORE(8)
763 USTORE(16)
764 USTORE(32)
765