trap.c revision 148568 
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#include <sys/cdefs.h>
35__FBSDID("$FreeBSD: head/sys/powerpc/aim/trap.c 148568 2005-07-30 11:14:31Z grehan $");
36
37#include "opt_ktrace.h"
38
39#include <sys/param.h>
40#include <sys/kdb.h>
41#include <sys/proc.h>
42#include <sys/ktr.h>
43#include <sys/lock.h>
44#include <sys/mutex.h>
45#include <sys/pioctl.h>
46#include <sys/reboot.h>
47#include <sys/syscall.h>
48#include <sys/sysent.h>
49#include <sys/systm.h>
50#include <sys/uio.h>
51#include <sys/signalvar.h>
52#ifdef KTRACE
53#include <sys/ktrace.h>
54#endif
55#include <sys/vmmeter.h>
56
57#include <vm/vm.h>
58#include <vm/pmap.h>
59#include <vm/vm_extern.h>
60#include <vm/vm_param.h>
61#include <vm/vm_kern.h>
62#include <vm/vm_map.h>
63#include <vm/vm_page.h>
64
65#include <machine/cpu.h>
66#include <machine/db_machdep.h>
67#include <machine/fpu.h>
68#include <machine/frame.h>
69#include <machine/pcb.h>
70#include <machine/pmap.h>
71#include <machine/psl.h>
72#include <machine/trap.h>
73#include <machine/spr.h>
74#include <machine/sr.h>
75
76void		trap(struct trapframe *);
77
78static void	trap_fatal(struct trapframe *frame);
79static void	printtrap(u_int vector, struct trapframe *frame, int isfatal,
80		    int user);
81static int	trap_pfault(struct trapframe *frame, int user);
82static int	fix_unaligned(struct thread *td, struct trapframe *frame);
83static int	handle_onfault(struct trapframe *frame);
84static void	syscall(struct trapframe *frame);
85
86static __inline void	setusr(u_int);
87
88int	setfault(faultbuf);		/* defined in locore.S */
89
90/* Why are these not defined in a header? */
91int	badaddr(void *, size_t);
92int	badaddr_read(void *, size_t, int *);
93
94extern char	*syscallnames[];
95
96struct powerpc_exception {
97	u_int	vector;
98	char	*name;
99};
100
101static struct powerpc_exception powerpc_exceptions[] = {
102	{ 0x0100, "system reset" },
103	{ 0x0200, "machine check" },
104	{ 0x0300, "data storage interrupt" },
105	{ 0x0400, "instruction storage interrupt" },
106	{ 0x0500, "external interrupt" },
107	{ 0x0600, "alignment" },
108	{ 0x0700, "program" },
109	{ 0x0800, "floating-point unavailable" },
110	{ 0x0900, "decrementer" },
111	{ 0x0c00, "system call" },
112	{ 0x0d00, "trace" },
113	{ 0x0e00, "floating-point assist" },
114	{ 0x0f00, "performance monitoring" },
115	{ 0x0f20, "altivec unavailable" },
116	{ 0x1000, "instruction tlb miss" },
117	{ 0x1100, "data load tlb miss" },
118	{ 0x1200, "data store tlb miss" },
119	{ 0x1300, "instruction breakpoint" },
120	{ 0x1400, "system management" },
121	{ 0x1600, "altivec assist" },
122	{ 0x1700, "thermal management" },
123	{ 0x2000, "run mode/trace" },
124	{ 0x3000, NULL }
125};
126
127static const char *
128trapname(u_int vector)
129{
130	struct	powerpc_exception *pe;
131
132	for (pe = powerpc_exceptions; pe->vector != 0x3000; pe++) {
133		if (pe->vector == vector)
134			return (pe->name);
135	}
136
137	return ("unknown");
138}
139
140void
141trap(struct trapframe *frame)
142{
143	struct thread	*td;
144	struct proc	*p;
145	int		sig, type, user;
146	u_int		sticks, ucode;
147
148	PCPU_LAZY_INC(cnt.v_trap);
149
150	td = PCPU_GET(curthread);
151	p = td->td_proc;
152
153	type = ucode = frame->exc;
154	sig = 0;
155	user = frame->srr1 & PSL_PR;
156	sticks = 0;
157
158	CTR3(KTR_TRAP, "trap: %s type=%s (%s)", p->p_comm,
159	    trapname(type), user ? "user" : "kernel");
160
161	if (user) {
162		sticks = td->td_sticks;
163		td->td_frame = frame;
164		if (td->td_ucred != p->p_ucred)
165			cred_update_thread(td);
166
167		/* User Mode Traps */
168		switch (type) {
169		case EXC_RUNMODETRC:
170		case EXC_TRC:
171			frame->srr1 &= ~PSL_SE;
172			sig = SIGTRAP;
173			break;
174
175		case EXC_DSI:
176		case EXC_ISI:
177			sig = trap_pfault(frame, 1);
178			break;
179
180		case EXC_SC:
181			syscall(frame);
182			break;
183
184		case EXC_FPU:
185			KASSERT((td->td_pcb->pcb_flags & PCB_FPU) != PCB_FPU,
186			    ("FPU already enabled for thread"));
187			enable_fpu(td);
188			break;
189
190#ifdef	ALTIVEC
191		case EXC_VEC:
192			if ((vecthread = PCPU_GET(vecthread)) != NULL) {
193				KASSERT(vecthread != td,
194				    ("altivec already enabled"));
195				save_vec(vecthread);
196			}
197			PCPU_SET(vecthread, td);
198			td->td_pcb->pcb_veccpu = PCPU_GET(cpuid);
199			enable_vec(td);
200			frame->srr1 |= PSL_VEC;
201			break;
202#else
203		case EXC_VEC:
204		case EXC_VECAST:
205			sig = SIGILL;
206			break;
207#endif /* ALTIVEC */
208
209		case EXC_ALI:
210			if (fix_unaligned(td, frame) != 0)
211				sig = SIGBUS;
212			else
213				frame->srr0 += 4;
214			break;
215
216		case EXC_PGM:
217			/* XXX temporarily */
218			/* XXX: Magic Number? */
219			if (frame->srr1 & 0x0002000)
220				sig = SIGTRAP;
221 			else
222				sig = SIGILL;
223			break;
224
225		default:
226			trap_fatal(frame);
227		}
228	} else {
229		/* Kernel Mode Traps */
230
231		KASSERT(cold || td->td_ucred != NULL,
232		    ("kernel trap doesn't have ucred"));
233		switch (type) {
234		case EXC_DSI:
235			if (trap_pfault(frame, 0) == 0)
236 				return;
237			break;
238		case EXC_MCHK:
239			if (handle_onfault(frame))
240 				return;
241			break;
242		default:
243			break;
244		}
245		trap_fatal(frame);
246	}
247
248#ifdef	ALTIVEC
249	if (td != PCPU_GET(vecthread) ||
250	    td->td_pcb->pcb_veccpu != PCPU_GET(cpuid))
251		frame->srr1 &= ~PSL_VEC;
252#endif /* ALTIVEC */
253
254	if (sig != 0) {
255		if (p->p_sysent->sv_transtrap != NULL)
256			sig = (p->p_sysent->sv_transtrap)(sig, type);
257		trapsignal(td, sig, ucode);
258	}
259
260	userret(td, frame, sticks);
261	mtx_assert(&Giant, MA_NOTOWNED);
262}
263
264static void
265trap_fatal(struct trapframe *frame)
266{
267
268	printtrap(frame->exc, frame, 1, (frame->srr1 & PSL_PR));
269#ifdef KDB
270	if ((debugger_on_panic || kdb_active) &&
271	    kdb_trap(frame->exc, 0, frame))
272		return;
273#endif
274	panic("%s trap", trapname(frame->exc));
275}
276
277static void
278printtrap(u_int vector, struct trapframe *frame, int isfatal, int user)
279{
280
281	printf("\n");
282	printf("%s %s trap:\n", isfatal ? "fatal" : "handled",
283	    user ? "user" : "kernel");
284	printf("\n");
285	printf("   exception       = 0x%x (%s)\n", vector >> 8,
286	    trapname(vector));
287	switch (vector) {
288	case EXC_DSI:
289		printf("   virtual address = 0x%x\n", frame->dar);
290		break;
291	case EXC_ISI:
292		printf("   virtual address = 0x%x\n", frame->srr0);
293		break;
294	}
295	printf("   srr0            = 0x%x\n", frame->srr0);
296	printf("   srr1            = 0x%x\n", frame->srr1);
297	printf("   curthread       = %p\n", curthread);
298	if (curthread != NULL)
299		printf("          pid = %d, comm = %s\n",
300		    curthread->td_proc->p_pid, curthread->td_proc->p_comm);
301	printf("\n");
302}
303
304/*
305 * Handles a fatal fault when we have onfault state to recover.  Returns
306 * non-zero if there was onfault recovery state available.
307 */
308static int
309handle_onfault(struct trapframe *frame)
310{
311	struct		thread *td;
312	faultbuf	*fb;
313
314	td = curthread;
315	fb = td->td_pcb->pcb_onfault;
316	if (fb != NULL) {
317		frame->srr0 = (*fb)[0];
318		frame->fixreg[1] = (*fb)[1];
319		frame->fixreg[2] = (*fb)[2];
320		frame->fixreg[3] = 1;
321		frame->cr = (*fb)[3];
322		bcopy(&(*fb)[4], &frame->fixreg[13],
323		    19 * sizeof(register_t));
324		return (1);
325	}
326	return (0);
327}
328
329void
330syscall(struct trapframe *frame)
331{
332	caddr_t		params;
333	struct		sysent *callp;
334	struct		thread *td;
335	struct		proc *p;
336	int		error, n;
337	size_t		narg;
338	register_t	args[10];
339	u_int		code;
340
341	td = PCPU_GET(curthread);
342	p = td->td_proc;
343
344	PCPU_LAZY_INC(cnt.v_syscall);
345
346	if (p->p_flag & P_SA)
347		thread_user_enter(td);
348
349	code = frame->fixreg[0];
350	params = (caddr_t)(frame->fixreg + FIRSTARG);
351	n = NARGREG;
352
353	if (p->p_sysent->sv_prepsyscall) {
354		/*
355		 * The prep code is MP aware.
356		 */
357		(*p->p_sysent->sv_prepsyscall)(frame, args, &code, &params);
358	} else if (code == SYS_syscall) {
359		/*
360		 * code is first argument,
361		 * followed by actual args.
362		 */
363		code = *(u_int *) params;
364		params += sizeof(register_t);
365		n -= 1;
366	} else if (code == SYS___syscall) {
367		/*
368		 * Like syscall, but code is a quad,
369		 * so as to maintain quad alignment
370		 * for the rest of the args.
371		 */
372		params += sizeof(register_t);
373		code = *(u_int *) params;
374		params += sizeof(register_t);
375		n -= 2;
376	}
377
378 	if (p->p_sysent->sv_mask)
379 		code &= p->p_sysent->sv_mask;
380
381 	if (code >= p->p_sysent->sv_size)
382 		callp = &p->p_sysent->sv_table[0];
383  	else
384 		callp = &p->p_sysent->sv_table[code];
385
386	narg = callp->sy_narg & SYF_ARGMASK;
387
388	if (narg > n) {
389		bcopy(params, args, n * sizeof(register_t));
390		error = copyin(MOREARGS(frame->fixreg[1]), args + n,
391			       (narg - n) * sizeof(register_t));
392		params = (caddr_t)args;
393	} else
394		error = 0;
395
396	CTR5(KTR_SYSC, "syscall: p=%s %s(%x %x %x)", p->p_comm,
397	     syscallnames[code],
398	     frame->fixreg[FIRSTARG],
399	     frame->fixreg[FIRSTARG+1],
400	     frame->fixreg[FIRSTARG+2]);
401
402#ifdef	KTRACE
403	if (KTRPOINT(td, KTR_SYSCALL))
404		ktrsyscall(code, narg, (register_t *)params);
405#endif
406	/*
407	 * Try to run the syscall without Giant if the syscall is MP safe.
408	 */
409	if ((callp->sy_narg & SYF_MPSAFE) == 0)
410		mtx_lock(&Giant);
411
412	if (error == 0) {
413		td->td_retval[0] = 0;
414		td->td_retval[1] = frame->fixreg[FIRSTARG + 1];
415
416		STOPEVENT(p, S_SCE, narg);
417
418		error = (*callp->sy_call)(td, params);
419
420		CTR3(KTR_SYSC, "syscall: p=%s %s ret=%x", p->p_comm,
421		     syscallnames[code], td->td_retval[0]);
422	}
423	switch (error) {
424	case 0:
425		if ((frame->fixreg[0] == SYS___syscall) &&
426		    (code != SYS_lseek)) {
427			/*
428			 * 64-bit return, 32-bit syscall. Fixup byte order
429			 */
430			frame->fixreg[FIRSTARG] = 0;
431			frame->fixreg[FIRSTARG + 1] = td->td_retval[0];
432		} else {
433			frame->fixreg[FIRSTARG] = td->td_retval[0];
434			frame->fixreg[FIRSTARG + 1] = td->td_retval[1];
435		}
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:
449		if (p->p_sysent->sv_errsize) {
450			if (error >= p->p_sysent->sv_errsize)
451				error = -1;	/* XXX */
452			else
453				error = p->p_sysent->sv_errtbl[error];
454		}
455		frame->fixreg[FIRSTARG] = error;
456		/* XXX: Magic number: Carry Flag Equivalent? */
457		frame->cr |= 0x10000000;
458		break;
459	}
460
461
462	if ((callp->sy_narg & SYF_MPSAFE) == 0)
463		mtx_unlock(&Giant);
464
465#ifdef	KTRACE
466	if (KTRPOINT(td, KTR_SYSRET))
467		ktrsysret(code, error, td->td_retval[0]);
468#endif
469
470	/*
471	 * Does the comment in the i386 code about errno apply here?
472	 */
473	STOPEVENT(p, S_SCX, code);
474
475	WITNESS_WARN(WARN_PANIC, NULL, "System call %s returning",
476	    (code >= 0 && code < SYS_MAXSYSCALL) ? syscallnames[code] : "???");
477	mtx_assert(&sched_lock, MA_NOTOWNED);
478	mtx_assert(&Giant, MA_NOTOWNED);
479}
480
481static int
482trap_pfault(struct trapframe *frame, int user)
483{
484	vm_offset_t	eva, va;
485	struct		thread *td;
486	struct		proc *p;
487	vm_map_t	map;
488	vm_prot_t	ftype;
489	int		rv;
490	u_int		user_sr;
491
492	td = curthread;
493	p = td->td_proc;
494	if (frame->exc == EXC_ISI) {
495		eva = frame->srr0;
496		ftype = VM_PROT_READ | VM_PROT_EXECUTE;
497	} else {
498		eva = frame->dar;
499		if (frame->dsisr & DSISR_STORE)
500			ftype = VM_PROT_WRITE;
501		else
502			ftype = VM_PROT_READ;
503	}
504
505	if (user) {
506		map = &p->p_vmspace->vm_map;
507	} else {
508		if ((eva >> ADDR_SR_SHFT) == USER_SR) {
509			if (p->p_vmspace == NULL)
510				return (SIGSEGV);
511
512			__asm ("mfsr %0, %1"
513			    : "=r"(user_sr)
514			    : "K"(USER_SR));
515			eva &= ADDR_PIDX | ADDR_POFF;
516			eva |= user_sr << ADDR_SR_SHFT;
517			map = &p->p_vmspace->vm_map;
518		} else {
519			map = kernel_map;
520		}
521	}
522	va = trunc_page(eva);
523
524	if (map != kernel_map) {
525		/*
526		 * Keep swapout from messing with us during this
527		 *	critical time.
528		 */
529		PROC_LOCK(p);
530		++p->p_lock;
531		PROC_UNLOCK(p);
532
533		/* Fault in the user page: */
534		rv = vm_fault(map, va, ftype,
535		      (ftype & VM_PROT_WRITE) ? VM_FAULT_DIRTY
536					      : VM_FAULT_NORMAL);
537
538		PROC_LOCK(p);
539		--p->p_lock;
540		PROC_UNLOCK(p);
541	} else {
542		/*
543		 * Don't have to worry about process locking or stacks in the
544		 * kernel.
545		 */
546		rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL);
547	}
548
549	if (rv == KERN_SUCCESS)
550		return (0);
551
552	if (!user && handle_onfault(frame))
553		return (0);
554
555	return (SIGSEGV);
556}
557
558static __inline void
559setusr(u_int content)
560{
561	__asm __volatile ("isync; mtsr %0,%1; isync"
562		      :: "n"(USER_SR), "r"(content));
563}
564
565int
566badaddr(void *addr, size_t size)
567{
568	return (badaddr_read(addr, size, NULL));
569}
570
571int
572badaddr_read(void *addr, size_t size, int *rptr)
573{
574	struct thread	*td;
575	faultbuf	env;
576	int		x;
577
578	/* Get rid of any stale machine checks that have been waiting.  */
579	__asm __volatile ("sync; isync");
580
581	td = PCPU_GET(curthread);
582
583	if (setfault(env)) {
584		td->td_pcb->pcb_onfault = 0;
585		__asm __volatile ("sync");
586		return 1;
587	}
588
589	__asm __volatile ("sync");
590
591	switch (size) {
592	case 1:
593		x = *(volatile int8_t *)addr;
594		break;
595	case 2:
596		x = *(volatile int16_t *)addr;
597		break;
598	case 4:
599		x = *(volatile int32_t *)addr;
600		break;
601	default:
602		panic("badaddr: invalid size (%d)", size);
603	}
604
605	/* Make sure we took the machine check, if we caused one. */
606	__asm __volatile ("sync; isync");
607
608	td->td_pcb->pcb_onfault = 0;
609	__asm __volatile ("sync");	/* To be sure. */
610
611	/* Use the value to avoid reorder. */
612	if (rptr)
613		*rptr = x;
614
615	return (0);
616}
617
618/*
619 * For now, this only deals with the particular unaligned access case
620 * that gcc tends to generate.  Eventually it should handle all of the
621 * possibilities that can happen on a 32-bit PowerPC in big-endian mode.
622 */
623
624static int
625fix_unaligned(struct thread *td, struct trapframe *frame)
626{
627	struct thread	*fputhread;
628	int		indicator, reg;
629	double		*fpr;
630
631	indicator = EXC_ALI_OPCODE_INDICATOR(frame->dsisr);
632
633	switch (indicator) {
634	case EXC_ALI_LFD:
635	case EXC_ALI_STFD:
636		reg = EXC_ALI_RST(frame->dsisr);
637		fpr = &td->td_pcb->pcb_fpu.fpr[reg];
638		fputhread = PCPU_GET(fputhread);
639
640		/* Juggle the FPU to ensure that we've initialized
641		 * the FPRs, and that their current state is in
642		 * the PCB.
643		 */
644		if (fputhread != td) {
645			if (fputhread)
646				save_fpu(fputhread);
647			enable_fpu(td);
648		}
649		save_fpu(td);
650
651		if (indicator == EXC_ALI_LFD) {
652			if (copyin((void *)frame->dar, fpr,
653			    sizeof(double)) != 0)
654				return -1;
655			enable_fpu(td);
656		} else {
657			if (copyout(fpr, (void *)frame->dar,
658			    sizeof(double)) != 0)
659				return -1;
660		}
661		return 0;
662		break;
663	}
664
665	return -1;
666}
667