trap.c revision 97395 
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 97395 2002-05-28 09:38:02Z benno $";
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/* These definitions should probably be somewhere else			XXX */
79#define	FIRSTARG	3		/* first argument is in reg 3 */
80#define	NARGREG		8		/* 8 args are in registers */
81#define	MOREARGS(sp)	((caddr_t)((int)(sp) + 8)) /* more args go here */
82
83#ifndef MULTIPROCESSOR
84extern int intr_depth;
85#endif
86
87void		trap(struct trapframe *);
88
89static void	trap_fatal(struct trapframe *frame);
90static void	printtrap(u_int vector, struct trapframe *frame, int isfatal,
91		    int user);
92static int	trap_pfault(struct trapframe *frame, int user);
93static int	fix_unaligned(struct thread *td, struct trapframe *frame);
94static int	handle_onfault(struct trapframe *frame);
95static void	syscall(struct trapframe *frame);
96
97static __inline void	setusr(u_int);
98
99int	setfault(faultbuf);		/* defined in locore.S */
100
101/* Why are these not defined in a header? */
102int	badaddr(void *, size_t);
103int	badaddr_read(void *, size_t, int *);
104
105#ifdef	WITNESS
106extern char	*syscallnames[];
107#endif
108
109struct powerpc_exception {
110	u_int	vector;
111	char	*name;
112};
113
114static struct powerpc_exception powerpc_exceptions[] = {
115	{ 0x0100, "system reset" },
116	{ 0x0200, "machine check" },
117	{ 0x0300, "data storage interrupt" },
118	{ 0x0400, "instruction storage interrupt" },
119	{ 0x0500, "external interrupt" },
120	{ 0x0600, "alignment" },
121	{ 0x0700, "program" },
122	{ 0x0800, "floating-point unavailable" },
123	{ 0x0900, "decrementer" },
124	{ 0x0c00, "system call" },
125	{ 0x0d00, "trace" },
126	{ 0x0e00, "floating-point assist" },
127	{ 0x0f00, "performance monitoring" },
128	{ 0x0f20, "altivec unavailable" },
129	{ 0x1000, "instruction tlb miss" },
130	{ 0x1100, "data load tlb miss" },
131	{ 0x1200, "data store tlb miss" },
132	{ 0x1300, "instruction breakpoint" },
133	{ 0x1400, "system management" },
134	{ 0x1600, "altivec assist" },
135	{ 0x1700, "thermal management" },
136	{ 0x2000, "run mode/trace" },
137	{ 0x3000, NULL }
138};
139
140static const char *
141trapname(u_int vector)
142{
143	struct	powerpc_exception *pe;
144
145	for (pe = powerpc_exceptions; pe->vector != 0x3000; pe++) {
146		if (pe->vector == vector)
147			return (pe->name);
148	}
149
150	return ("unknown");
151}
152
153void
154trap(struct trapframe *frame)
155{
156	struct thread	*td, *fputhread;
157	struct proc	*p;
158	int		sig, type, user;
159	u_int		sticks, ucode;
160
161	atomic_add_int(&cnt.v_trap, 1);
162
163	td = PCPU_GET(curthread);
164	p = td->td_proc;
165
166	type = ucode = frame->exc;
167	sig = 0;
168	user = frame->srr1 & PSL_PR;
169	sticks = 0;
170
171	CTR3(KTR_TRAP, "trap: %s type=%s (%s)", p->p_comm,
172	    trapname(type), user ? "user" : "kernel");
173
174	if (user) {
175		sticks = td->td_kse->ke_sticks;
176		td->td_frame = frame;
177		if (td->td_ucred != p->p_ucred)
178			cred_update_thread(td);
179
180		/* User Mode Traps */
181		switch (type) {
182		case EXC_RUNMODETRC:
183		case EXC_TRC:
184			frame->srr1 &= ~PSL_SE;
185			sig = SIGTRAP;
186			break;
187
188		case EXC_DSI:
189		case EXC_ISI:
190			sig = trap_pfault(frame, 1);
191			break;
192
193		case EXC_SC:
194			syscall(frame);
195			break;
196
197		case EXC_FPU:
198			if ((fputhread = PCPU_GET(fputhread)) != NULL) {
199				KASSERT(fputhread != td,
200				    ("floating-point already enabled"));
201				save_fpu(fputhread);
202			}
203			PCPU_SET(fputhread, td);
204			td->td_pcb->pcb_fpcpu = PCPU_GET(cpuid);
205			enable_fpu(td);
206			frame->srr1 |= PSL_FP;
207			break;
208
209#ifdef	ALTIVEC
210		case EXC_VEC:
211			if ((vecthread = PCPU_GET(vecthread)) != NULL) {
212				KASSERT(vecthread != td,
213				    ("altivec already enabled"));
214				save_vec(vecthread);
215			}
216			PCPU_SET(vecthread, td);
217			td->td_pcb->pcb_veccpu = PCPU_GET(cpuid);
218			enable_vec(td);
219			frame->srr1 |= PSL_VEC;
220			break;
221#endif /* ALTIVEC */
222
223		case EXC_ALI:
224			if (fix_unaligned(td, frame) != 0)
225				sig = SIGBUS;
226			else
227				frame->srr0 += 4;
228			break;
229
230		case EXC_PGM:
231			/* XXX temporarily */
232			/* XXX: Magic Number? */
233			if (frame->srr1 & 0x0002000)
234				sig = SIGTRAP;
235 			else
236				sig = SIGILL;
237			break;
238
239		default:
240			trap_fatal(frame);
241		}
242	} else {
243		/* Kernel Mode Traps */
244
245		KASSERT(cold || td->td_ucred != NULL,
246		    ("kernel trap doesn't have ucred"));
247		switch (type) {
248		case EXC_DSI:
249			if (trap_pfault(frame, 0) == 0)
250 				return;
251			break;
252		case EXC_MCHK:
253			if (handle_onfault(frame))
254 				return;
255			break;
256		default:
257			trap_fatal(frame);
258		}
259	}
260
261	if (td != PCPU_GET(fputhread) ||
262	    td->td_pcb->pcb_fpcpu != PCPU_GET(cpuid))
263		frame->srr1 &= ~PSL_FP;
264
265#ifdef	ALTIVEC
266	if (td != PCPU_GET(vecthread) ||
267	    td->td_pcb->pcb_veccpu != PCPU_GET(cpuid))
268		frame->srr1 &= ~PSL_VEC;
269#endif /* ALTIVEC */
270
271	if (sig != 0) {
272		if (p->p_sysent->sv_transtrap != NULL)
273			sig = (p->p_sysent->sv_transtrap)(sig, type);
274		trapsignal(p, sig, ucode);
275	}
276
277	userret(td, frame, sticks);
278	mtx_assert(&Giant, MA_NOTOWNED);
279#ifdef	DIAGNOSTIC
280	cred_free_thread(td);
281#endif	/* DIAGNOSTIC */
282}
283
284static void
285trap_fatal(struct trapframe *frame)
286{
287
288	printtrap(frame->exc, frame, 1, (frame->srr1 & PSL_PR));
289#ifdef DDB
290	if ((debugger_on_panic || db_active) && kdb_trap(frame->exc, 0, frame))
291		return;
292#endif
293	panic("%s trap", trapname(frame->exc));
294}
295
296static void
297printtrap(u_int vector, struct trapframe *frame, int isfatal, int user)
298{
299
300	printf("\n");
301	printf("%s %s trap:\n", isfatal ? "fatal" : "handled",
302	    user ? "user" : "kernel");
303	printf("\n");
304	printf("   exception       = 0x%x (%s)\n", vector >> 8,
305	    trapname(vector));
306	switch (vector) {
307	case EXC_DSI:
308		printf("   virtual address = 0x%x\n", frame->dar);
309		break;
310	case EXC_ISI:
311		printf("   virtual address = 0x%x\n", frame->srr0);
312		break;
313	}
314	printf("   srr0            = 0x%x\n", frame->srr0);
315	printf("   srr1            = 0x%x\n", frame->srr1);
316	printf("   curthread       = %p\n", curthread);
317	if (curthread != NULL)
318		printf("          pid = %d, comm = %s\n",
319		    curthread->td_proc->p_pid, curthread->td_proc->p_comm);
320	printf("\n");
321}
322
323/*
324 * Handles a fatal fault when we have onfault state to recover.  Returns
325 * non-zero if there was onfault recovery state available.
326 */
327static int
328handle_onfault(struct trapframe *frame)
329{
330	struct		thread *td;
331	faultbuf	*fb;
332
333	td = curthread;
334	fb = td->td_pcb->pcb_onfault;
335	if (fb != NULL) {
336		frame->srr0 = (*fb)[0];
337		frame->fixreg[1] = (*fb)[1];
338		frame->fixreg[2] = (*fb)[2];
339		frame->cr = (*fb)[3];
340		bcopy(&(*fb)[4], &frame->fixreg[13],
341		    19 * sizeof(register_t));
342		return (1);
343	}
344	return (0);
345}
346
347void
348syscall(struct trapframe *frame)
349{
350	caddr_t		params;
351	struct		sysent *callp;
352	struct		thread *td;
353	struct		proc *p;
354	int		error, n;
355	size_t		narg;
356	register_t	args[10];
357	u_int		code;
358
359	td = PCPU_GET(curthread);
360	p = td->td_proc;
361
362	atomic_add_int(&cnt.v_syscall, 1);
363
364	code = frame->fixreg[0];
365	params = (caddr_t)(frame->fixreg + FIRSTARG);
366	n = NARGREG;
367
368	if (p->p_sysent->sv_prepsyscall) {
369		/*
370		 * The prep code is MP aware.
371		 */
372		(*p->p_sysent->sv_prepsyscall)(frame, args, &code, &params);
373	} else if (code == SYS_syscall) {
374		/*
375		 * code is first argument,
376		 * followed by actual args.
377		 */
378		code = *params++;
379		n -= 1;
380	} else if (code == SYS___syscall) {
381		/*
382		 * Like syscall, but code is a quad,
383		 * so as to maintain quad alignment
384		 * for the rest of the args.
385		 */
386		params++;
387		code = *params++;
388		n -= 2;
389	}
390
391 	if (p->p_sysent->sv_mask)
392 		code &= p->p_sysent->sv_mask;
393
394 	if (code >= p->p_sysent->sv_size)
395 		callp = &p->p_sysent->sv_table[0];
396  	else
397 		callp = &p->p_sysent->sv_table[code];
398
399	narg = callp->sy_narg & SYF_ARGMASK;
400
401	if (narg > n * sizeof(register_t)) {
402		bcopy(params, args, n * sizeof(register_t));
403		error = copyin(MOREARGS(frame->fixreg[1]), args + n,
404			narg - n * sizeof(register_t));
405		if (error) {
406#ifdef	KTRACE
407			/* Can't get all the arguments! */
408			if (KTRPOINT(p, KTR_SYSCALL))
409				ktrsyscall(p->p_tracep, code, narg, args);
410#endif
411			goto bad;
412		}
413		params = (caddr_t)args;
414	}
415
416	/*
417	 * Try to run the syscall without Giant if the syscall is MP safe.
418	 */
419	if ((callp->sy_narg & SYF_MPSAFE) == 0)
420		mtx_lock(&Giant);
421
422#ifdef	KTRACE
423	if (KTRPOINT(p, KTR_SYSCALL))
424		ktrsyscall(p->p_tracep, code, narg, params);
425#endif
426	td->td_retval[0] = 0;
427	td->td_retval[1] = frame->fixreg[FIRSTARG + 1];
428
429	STOPEVENT(p, S_SCE, narg);
430
431	error = (*callp->sy_call)(td, params);
432	switch (error) {
433	case 0:
434		frame->fixreg[FIRSTARG] = td->td_retval[0];
435		frame->fixreg[FIRSTARG + 1] = td->td_retval[1];
436		/* XXX: Magic number */
437		frame->cr &= ~0x10000000;
438		break;
439	case ERESTART:
440		/*
441		 * Set user's pc back to redo the system call.
442		 */
443		frame->srr0 -= 4;
444		break;
445	case EJUSTRETURN:
446		/* nothing to do */
447		break;
448	default:
449bad:
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#ifdef	KTRACE
464	if (KTRPOINT(p, KTR_SYSRET))
465		ktrsysret(p->p_tracep, code, error, td->td_retval[0]);
466#endif
467
468	if ((callp->sy_narg & SYF_MPSAFE) == 0)
469		mtx_unlock(&Giant);
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_READ | 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