trap.c revision 110190 
1/*
2 * Copyright (C) 1995, 1996 Wolfgang Solfrank.
3 * Copyright (C) 1995, 1996 TooLs GmbH.
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 * 3. All advertising materials mentioning features or use of this software
15 *    must display the following acknowledgement:
16 *	This product includes software developed by TooLs GmbH.
17 * 4. The name of TooLs GmbH may not be used to endorse or promote products
18 *    derived from this software without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR
21 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
22 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
23 * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
24 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
25 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
26 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
27 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
28 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
29 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30 *
31 * $NetBSD: trap.c,v 1.58 2002/03/04 04:07:35 dbj Exp $
32 */
33
34#ifndef lint
35static const char rcsid[] =
36  "$FreeBSD: head/sys/powerpc/aim/trap.c 110190 2003-02-01 12:17:09Z julian $";
37#endif /* not lint */
38
39#include "opt_ddb.h"
40#include "opt_ktrace.h"
41
42#include <sys/param.h>
43#include <sys/proc.h>
44#include <sys/ktr.h>
45#include <sys/lock.h>
46#include <sys/mutex.h>
47#include <sys/pioctl.h>
48#include <sys/reboot.h>
49#include <sys/syscall.h>
50#include <sys/sysent.h>
51#include <sys/systm.h>
52#include <sys/uio.h>
53#include <sys/user.h>
54#ifdef KTRACE
55#include <sys/ktrace.h>
56#endif
57#include <sys/vmmeter.h>
58
59#include <vm/vm.h>
60#include <vm/pmap.h>
61#include <vm/vm_extern.h>
62#include <vm/vm_param.h>
63#include <vm/vm_kern.h>
64#include <vm/vm_map.h>
65#include <vm/vm_page.h>
66
67#include <machine/cpu.h>
68#include <machine/db_machdep.h>
69#include <machine/fpu.h>
70#include <machine/frame.h>
71#include <machine/pcb.h>
72#include <machine/pmap.h>
73#include <machine/psl.h>
74#include <machine/trap.h>
75#include <machine/spr.h>
76#include <machine/sr.h>
77
78#include <ddb/ddb.h>
79
80#ifndef MULTIPROCESSOR
81extern int intr_depth;
82#endif
83
84void		trap(struct trapframe *);
85
86static void	trap_fatal(struct trapframe *frame);
87static void	printtrap(u_int vector, struct trapframe *frame, int isfatal,
88		    int user);
89static int	trap_pfault(struct trapframe *frame, int user);
90static int	fix_unaligned(struct thread *td, struct trapframe *frame);
91static int	handle_onfault(struct trapframe *frame);
92static void	syscall(struct trapframe *frame);
93
94static __inline void	setusr(u_int);
95
96int	setfault(faultbuf);		/* defined in locore.S */
97
98/* Why are these not defined in a header? */
99int	badaddr(void *, size_t);
100int	badaddr_read(void *, size_t, int *);
101
102#ifdef	WITNESS
103extern char	*syscallnames[];
104#endif
105
106struct powerpc_exception {
107	u_int	vector;
108	char	*name;
109};
110
111static struct powerpc_exception powerpc_exceptions[] = {
112	{ 0x0100, "system reset" },
113	{ 0x0200, "machine check" },
114	{ 0x0300, "data storage interrupt" },
115	{ 0x0400, "instruction storage interrupt" },
116	{ 0x0500, "external interrupt" },
117	{ 0x0600, "alignment" },
118	{ 0x0700, "program" },
119	{ 0x0800, "floating-point unavailable" },
120	{ 0x0900, "decrementer" },
121	{ 0x0c00, "system call" },
122	{ 0x0d00, "trace" },
123	{ 0x0e00, "floating-point assist" },
124	{ 0x0f00, "performance monitoring" },
125	{ 0x0f20, "altivec unavailable" },
126	{ 0x1000, "instruction tlb miss" },
127	{ 0x1100, "data load tlb miss" },
128	{ 0x1200, "data store tlb miss" },
129	{ 0x1300, "instruction breakpoint" },
130	{ 0x1400, "system management" },
131	{ 0x1600, "altivec assist" },
132	{ 0x1700, "thermal management" },
133	{ 0x2000, "run mode/trace" },
134	{ 0x3000, NULL }
135};
136
137static const char *
138trapname(u_int vector)
139{
140	struct	powerpc_exception *pe;
141
142	for (pe = powerpc_exceptions; pe->vector != 0x3000; pe++) {
143		if (pe->vector == vector)
144			return (pe->name);
145	}
146
147	return ("unknown");
148}
149
150void
151trap(struct trapframe *frame)
152{
153	struct thread	*td, *fputhread;
154	struct proc	*p;
155	int		sig, type, user;
156	u_int		sticks, ucode;
157
158	atomic_add_int(&cnt.v_trap, 1);
159
160	td = PCPU_GET(curthread);
161	p = td->td_proc;
162
163	type = ucode = frame->exc;
164	sig = 0;
165	user = frame->srr1 & PSL_PR;
166	sticks = 0;
167
168	CTR3(KTR_TRAP, "trap: %s type=%s (%s)", p->p_comm,
169	    trapname(type), user ? "user" : "kernel");
170
171	if (user) {
172		sticks = td->td_kse->ke_sticks;
173		td->td_frame = frame;
174		if (td->td_ucred != p->p_ucred)
175			cred_update_thread(td);
176
177		/* User Mode Traps */
178		switch (type) {
179		case EXC_RUNMODETRC:
180		case EXC_TRC:
181			frame->srr1 &= ~PSL_SE;
182			sig = SIGTRAP;
183			break;
184
185		case EXC_DSI:
186		case EXC_ISI:
187			sig = trap_pfault(frame, 1);
188			break;
189
190		case EXC_SC:
191			syscall(frame);
192			break;
193
194		case EXC_FPU:
195			if ((fputhread = PCPU_GET(fputhread)) != NULL) {
196				save_fpu(fputhread);
197			}
198			PCPU_SET(fputhread, td);
199			td->td_pcb->pcb_fpcpu = PCPU_GET(cpuid);
200			enable_fpu(td);
201			frame->srr1 |= PSL_FP;
202			break;
203
204#ifdef	ALTIVEC
205		case EXC_VEC:
206			if ((vecthread = PCPU_GET(vecthread)) != NULL) {
207				KASSERT(vecthread != td,
208				    ("altivec already enabled"));
209				save_vec(vecthread);
210			}
211			PCPU_SET(vecthread, td);
212			td->td_pcb->pcb_veccpu = PCPU_GET(cpuid);
213			enable_vec(td);
214			frame->srr1 |= PSL_VEC;
215			break;
216#endif /* ALTIVEC */
217
218		case EXC_ALI:
219			if (fix_unaligned(td, frame) != 0)
220				sig = SIGBUS;
221			else
222				frame->srr0 += 4;
223			break;
224
225		case EXC_PGM:
226			/* XXX temporarily */
227			/* XXX: Magic Number? */
228			if (frame->srr1 & 0x0002000)
229				sig = SIGTRAP;
230 			else
231				sig = SIGILL;
232			break;
233
234		default:
235			trap_fatal(frame);
236		}
237	} else {
238		/* Kernel Mode Traps */
239
240		KASSERT(cold || td->td_ucred != NULL,
241		    ("kernel trap doesn't have ucred"));
242		switch (type) {
243		case EXC_DSI:
244			if (trap_pfault(frame, 0) == 0)
245 				return;
246			break;
247		case EXC_MCHK:
248			if (handle_onfault(frame))
249 				return;
250			break;
251		default:
252			trap_fatal(frame);
253		}
254	}
255
256	if (td != PCPU_GET(fputhread) ||
257	    td->td_pcb->pcb_fpcpu != PCPU_GET(cpuid))
258		frame->srr1 &= ~PSL_FP;
259
260#ifdef	ALTIVEC
261	if (td != PCPU_GET(vecthread) ||
262	    td->td_pcb->pcb_veccpu != PCPU_GET(cpuid))
263		frame->srr1 &= ~PSL_VEC;
264#endif /* ALTIVEC */
265
266	if (sig != 0) {
267		if (p->p_sysent->sv_transtrap != NULL)
268			sig = (p->p_sysent->sv_transtrap)(sig, type);
269		trapsignal(p, sig, ucode);
270	}
271
272	userret(td, frame, sticks);
273	mtx_assert(&Giant, MA_NOTOWNED);
274#ifdef	DIAGNOSTIC
275	cred_free_thread(td);
276#endif	/* DIAGNOSTIC */
277}
278
279static void
280trap_fatal(struct trapframe *frame)
281{
282
283	printtrap(frame->exc, frame, 1, (frame->srr1 & PSL_PR));
284#ifdef DDB
285	if ((debugger_on_panic || db_active) && kdb_trap(frame->exc, frame))
286		return;
287#endif
288	panic("%s trap", trapname(frame->exc));
289}
290
291static void
292printtrap(u_int vector, struct trapframe *frame, int isfatal, int user)
293{
294
295	printf("\n");
296	printf("%s %s trap:\n", isfatal ? "fatal" : "handled",
297	    user ? "user" : "kernel");
298	printf("\n");
299	printf("   exception       = 0x%x (%s)\n", vector >> 8,
300	    trapname(vector));
301	switch (vector) {
302	case EXC_DSI:
303		printf("   virtual address = 0x%x\n", frame->dar);
304		break;
305	case EXC_ISI:
306		printf("   virtual address = 0x%x\n", frame->srr0);
307		break;
308	}
309	printf("   srr0            = 0x%x\n", frame->srr0);
310	printf("   srr1            = 0x%x\n", frame->srr1);
311	printf("   curthread       = %p\n", curthread);
312	if (curthread != NULL)
313		printf("          pid = %d, comm = %s\n",
314		    curthread->td_proc->p_pid, curthread->td_proc->p_comm);
315	printf("\n");
316}
317
318/*
319 * Handles a fatal fault when we have onfault state to recover.  Returns
320 * non-zero if there was onfault recovery state available.
321 */
322static int
323handle_onfault(struct trapframe *frame)
324{
325	struct		thread *td;
326	faultbuf	*fb;
327
328	td = curthread;
329	fb = td->td_pcb->pcb_onfault;
330	if (fb != NULL) {
331		frame->srr0 = (*fb)[0];
332		frame->fixreg[1] = (*fb)[1];
333		frame->fixreg[2] = (*fb)[2];
334		frame->cr = (*fb)[3];
335		bcopy(&(*fb)[4], &frame->fixreg[13],
336		    19 * sizeof(register_t));
337		return (1);
338	}
339	return (0);
340}
341
342void
343syscall(struct trapframe *frame)
344{
345	caddr_t		params;
346	struct		sysent *callp;
347	struct		thread *td;
348	struct		proc *p;
349	int		error, n;
350	size_t		narg;
351	register_t	args[10];
352	u_int		code;
353
354	td = PCPU_GET(curthread);
355	p = td->td_proc;
356
357	atomic_add_int(&cnt.v_syscall, 1);
358
359	code = frame->fixreg[0];
360	params = (caddr_t)(frame->fixreg + FIRSTARG);
361	n = NARGREG;
362
363	if (p->p_sysent->sv_prepsyscall) {
364		/*
365		 * The prep code is MP aware.
366		 */
367		(*p->p_sysent->sv_prepsyscall)(frame, args, &code, &params);
368	} else if (code == SYS_syscall) {
369		/*
370		 * code is first argument,
371		 * followed by actual args.
372		 */
373		code = *(u_int *) params;
374		params += sizeof(register_t);
375		n -= 1;
376	} else if (code == SYS___syscall) {
377		/*
378		 * Like syscall, but code is a quad,
379		 * so as to maintain quad alignment
380		 * for the rest of the args.
381		 */
382		params += sizeof(register_t);
383		code = *(u_int *) params;
384		params += sizeof(register_t);
385		n -= 2;
386	}
387
388 	if (p->p_sysent->sv_mask)
389 		code &= p->p_sysent->sv_mask;
390
391 	if (code >= p->p_sysent->sv_size)
392 		callp = &p->p_sysent->sv_table[0];
393  	else
394 		callp = &p->p_sysent->sv_table[code];
395
396	narg = callp->sy_narg & SYF_ARGMASK;
397
398	if (narg > n) {
399		bcopy(params, args, n * sizeof(register_t));
400		error = copyin(MOREARGS(frame->fixreg[1]), args + n,
401			       (narg - n) * sizeof(register_t));
402		params = (caddr_t)args;
403	} else
404		error = 0;
405
406#ifdef	KTRACE
407	if (KTRPOINT(td, KTR_SYSCALL))
408		ktrsyscall(code, narg, (register_t *)params);
409#endif
410	/*
411	 * Try to run the syscall without Giant if the syscall is MP safe.
412	 */
413	if ((callp->sy_narg & SYF_MPSAFE) == 0)
414		mtx_lock(&Giant);
415
416	if (error == 0) {
417		td->td_retval[0] = 0;
418		td->td_retval[1] = frame->fixreg[FIRSTARG + 1];
419
420		STOPEVENT(p, S_SCE, narg);
421
422		error = (*callp->sy_call)(td, params);
423	}
424	switch (error) {
425	case 0:
426		if ((frame->fixreg[0] == SYS___syscall) &&
427		    (code != SYS_lseek)) {
428			/*
429			 * 64-bit return, 32-bit syscall. Fixup byte order
430			 */
431			frame->fixreg[FIRSTARG] = 0;
432			frame->fixreg[FIRSTARG + 1] = td->td_retval[0];
433		} else {
434			frame->fixreg[FIRSTARG] = td->td_retval[0];
435			frame->fixreg[FIRSTARG + 1] = td->td_retval[1];
436		}
437		/* XXX: Magic number */
438		frame->cr &= ~0x10000000;
439		break;
440	case ERESTART:
441		/*
442		 * Set user's pc back to redo the system call.
443		 */
444		frame->srr0 -= 4;
445		break;
446	case EJUSTRETURN:
447		/* nothing to do */
448		break;
449	default:
450		if (p->p_sysent->sv_errsize) {
451			if (error >= p->p_sysent->sv_errsize)
452				error = -1;	/* XXX */
453			else
454				error = p->p_sysent->sv_errtbl[error];
455		}
456		frame->fixreg[FIRSTARG] = error;
457		/* XXX: Magic number: Carry Flag Equivalent? */
458		frame->cr |= 0x10000000;
459		break;
460	}
461
462
463	if ((callp->sy_narg & SYF_MPSAFE) == 0)
464		mtx_unlock(&Giant);
465
466#ifdef	KTRACE
467	if (KTRPOINT(td, KTR_SYSRET))
468		ktrsysret(code, error, td->td_retval[0]);
469#endif
470
471	/*
472	 * Does the comment in the i386 code about errno apply here?
473	 */
474	STOPEVENT(p, S_SCX, code);
475
476#ifdef WITNESS
477	if (witness_list(td)) {
478		panic("system call %s returning with mutex(s) held\n",
479		    syscallnames[code]);
480	}
481#endif
482	mtx_assert(&sched_lock, MA_NOTOWNED);
483	mtx_assert(&Giant, MA_NOTOWNED);
484}
485
486static int
487trap_pfault(struct trapframe *frame, int user)
488{
489	vm_offset_t	eva, va;
490	struct		thread *td;
491	struct		proc *p;
492	vm_map_t	map;
493	vm_prot_t	ftype;
494	int		rv;
495	u_int		user_sr;
496
497	td = curthread;
498	p = td->td_proc;
499	if (frame->exc == EXC_ISI) {
500		eva = frame->srr0;
501		ftype = VM_PROT_READ | VM_PROT_EXECUTE;
502	} else {
503		eva = frame->dar;
504		if (frame->dsisr & DSISR_STORE)
505			ftype = VM_PROT_WRITE;
506		else
507			ftype = VM_PROT_READ;
508	}
509
510	if (user) {
511		map = &p->p_vmspace->vm_map;
512	} else {
513		if ((eva >> ADDR_SR_SHFT) == USER_SR) {
514			if (p->p_vmspace == NULL)
515				return (SIGSEGV);
516
517			__asm ("mfsr %0, %1"
518			    : "=r"(user_sr)
519			    : "K"(USER_SR));
520			eva &= ADDR_PIDX | ADDR_POFF;
521			eva |= user_sr << ADDR_SR_SHFT;
522			map = &p->p_vmspace->vm_map;
523		} else {
524			map = kernel_map;
525		}
526	}
527	va = trunc_page(eva);
528
529	mtx_lock(&Giant);
530	if (map != kernel_map) {
531		/*
532		 * Keep swapout from messing with us during this
533		 *	critical time.
534		 */
535		PROC_LOCK(p);
536		++p->p_lock;
537		PROC_UNLOCK(p);
538
539		/* Fault in the user page: */
540		rv = vm_fault(map, va, ftype,
541		      (ftype & VM_PROT_WRITE) ? VM_FAULT_DIRTY
542					      : VM_FAULT_NORMAL);
543
544		PROC_LOCK(p);
545		--p->p_lock;
546		PROC_UNLOCK(p);
547	} else {
548		/*
549		 * Don't have to worry about process locking or stacks in the
550		 * kernel.
551		 */
552		rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL);
553	}
554	mtx_unlock(&Giant);
555
556	if (rv == KERN_SUCCESS)
557		return (0);
558
559	if (!user && handle_onfault(frame))
560		return (0);
561
562	return (SIGSEGV);
563}
564
565static __inline void
566setusr(u_int content)
567{
568	__asm __volatile ("isync; mtsr %0,%1; isync"
569		      :: "n"(USER_SR), "r"(content));
570}
571
572int
573badaddr(void *addr, size_t size)
574{
575	return (badaddr_read(addr, size, NULL));
576}
577
578int
579badaddr_read(void *addr, size_t size, int *rptr)
580{
581	struct thread	*td;
582	faultbuf	env;
583	int		x;
584
585	/* Get rid of any stale machine checks that have been waiting.  */
586	__asm __volatile ("sync; isync");
587
588	td = PCPU_GET(curthread);
589
590	if (setfault(env)) {
591		td->td_pcb->pcb_onfault = 0;
592		__asm __volatile ("sync");
593		return 1;
594	}
595
596	__asm __volatile ("sync");
597
598	switch (size) {
599	case 1:
600		x = *(volatile int8_t *)addr;
601		break;
602	case 2:
603		x = *(volatile int16_t *)addr;
604		break;
605	case 4:
606		x = *(volatile int32_t *)addr;
607		break;
608	default:
609		panic("badaddr: invalid size (%d)", size);
610	}
611
612	/* Make sure we took the machine check, if we caused one. */
613	__asm __volatile ("sync; isync");
614
615	td->td_pcb->pcb_onfault = 0;
616	__asm __volatile ("sync");	/* To be sure. */
617
618	/* Use the value to avoid reorder. */
619	if (rptr)
620		*rptr = x;
621
622	return (0);
623}
624
625/*
626 * For now, this only deals with the particular unaligned access case
627 * that gcc tends to generate.  Eventually it should handle all of the
628 * possibilities that can happen on a 32-bit PowerPC in big-endian mode.
629 */
630
631static int
632fix_unaligned(struct thread *td, struct trapframe *frame)
633{
634	struct thread	*fputhread;
635	int		indicator, reg;
636	double		*fpr;
637
638	indicator = EXC_ALI_OPCODE_INDICATOR(frame->dsisr);
639
640	switch (indicator) {
641	case EXC_ALI_LFD:
642	case EXC_ALI_STFD:
643		reg = EXC_ALI_RST(frame->dsisr);
644		fpr = &td->td_pcb->pcb_fpu.fpr[reg];
645		fputhread = PCPU_GET(fputhread);
646
647		/* Juggle the FPU to ensure that we've initialized
648		 * the FPRs, and that their current state is in
649		 * the PCB.
650		 */
651		if (fputhread != td) {
652			if (fputhread)
653				save_fpu(fputhread);
654			enable_fpu(td);
655		}
656		save_fpu(td);
657
658		if (indicator == EXC_ALI_LFD) {
659			if (copyin((void *)frame->dar, fpr,
660			    sizeof(double)) != 0)
661				return -1;
662			enable_fpu(td);
663		} else {
664			if (copyout(fpr, (void *)frame->dar,
665			    sizeof(double)) != 0)
666				return -1;
667		}
668		return 0;
669		break;
670	}
671
672	return -1;
673}
674