trap.c revision 97397 
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 97397 2002-05-28 12:24:29Z 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#ifndef MULTIPROCESSOR
79extern int intr_depth;
80#endif
81
82void		trap(struct trapframe *);
83
84static void	trap_fatal(struct trapframe *frame);
85static void	printtrap(u_int vector, struct trapframe *frame, int isfatal,
86		    int user);
87static int	trap_pfault(struct trapframe *frame, int user);
88static int	fix_unaligned(struct thread *td, struct trapframe *frame);
89static int	handle_onfault(struct trapframe *frame);
90static void	syscall(struct trapframe *frame);
91
92static __inline void	setusr(u_int);
93
94int	setfault(faultbuf);		/* defined in locore.S */
95
96/* Why are these not defined in a header? */
97int	badaddr(void *, size_t);
98int	badaddr_read(void *, size_t, int *);
99
100#ifdef	WITNESS
101extern char	*syscallnames[];
102#endif
103
104struct powerpc_exception {
105	u_int	vector;
106	char	*name;
107};
108
109static struct powerpc_exception powerpc_exceptions[] = {
110	{ 0x0100, "system reset" },
111	{ 0x0200, "machine check" },
112	{ 0x0300, "data storage interrupt" },
113	{ 0x0400, "instruction storage interrupt" },
114	{ 0x0500, "external interrupt" },
115	{ 0x0600, "alignment" },
116	{ 0x0700, "program" },
117	{ 0x0800, "floating-point unavailable" },
118	{ 0x0900, "decrementer" },
119	{ 0x0c00, "system call" },
120	{ 0x0d00, "trace" },
121	{ 0x0e00, "floating-point assist" },
122	{ 0x0f00, "performance monitoring" },
123	{ 0x0f20, "altivec unavailable" },
124	{ 0x1000, "instruction tlb miss" },
125	{ 0x1100, "data load tlb miss" },
126	{ 0x1200, "data store tlb miss" },
127	{ 0x1300, "instruction breakpoint" },
128	{ 0x1400, "system management" },
129	{ 0x1600, "altivec assist" },
130	{ 0x1700, "thermal management" },
131	{ 0x2000, "run mode/trace" },
132	{ 0x3000, NULL }
133};
134
135static const char *
136trapname(u_int vector)
137{
138	struct	powerpc_exception *pe;
139
140	for (pe = powerpc_exceptions; pe->vector != 0x3000; pe++) {
141		if (pe->vector == vector)
142			return (pe->name);
143	}
144
145	return ("unknown");
146}
147
148void
149trap(struct trapframe *frame)
150{
151	struct thread	*td, *fputhread;
152	struct proc	*p;
153	int		sig, type, user;
154	u_int		sticks, ucode;
155
156	atomic_add_int(&cnt.v_trap, 1);
157
158	td = PCPU_GET(curthread);
159	p = td->td_proc;
160
161	type = ucode = frame->exc;
162	sig = 0;
163	user = frame->srr1 & PSL_PR;
164	sticks = 0;
165
166	CTR3(KTR_TRAP, "trap: %s type=%s (%s)", p->p_comm,
167	    trapname(type), user ? "user" : "kernel");
168
169	if (user) {
170		sticks = td->td_kse->ke_sticks;
171		td->td_frame = frame;
172		if (td->td_ucred != p->p_ucred)
173			cred_update_thread(td);
174
175		/* User Mode Traps */
176		switch (type) {
177		case EXC_RUNMODETRC:
178		case EXC_TRC:
179			frame->srr1 &= ~PSL_SE;
180			sig = SIGTRAP;
181			break;
182
183		case EXC_DSI:
184		case EXC_ISI:
185			sig = trap_pfault(frame, 1);
186			break;
187
188		case EXC_SC:
189			syscall(frame);
190			break;
191
192		case EXC_FPU:
193			if ((fputhread = PCPU_GET(fputhread)) != NULL) {
194				KASSERT(fputhread != td,
195				    ("floating-point already enabled"));
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, 0, 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 = *params++;
374		n -= 1;
375	} else if (code == SYS___syscall) {
376		/*
377		 * Like syscall, but code is a quad,
378		 * so as to maintain quad alignment
379		 * for the rest of the args.
380		 */
381		params++;
382		code = *params++;
383		n -= 2;
384	}
385
386 	if (p->p_sysent->sv_mask)
387 		code &= p->p_sysent->sv_mask;
388
389 	if (code >= p->p_sysent->sv_size)
390 		callp = &p->p_sysent->sv_table[0];
391  	else
392 		callp = &p->p_sysent->sv_table[code];
393
394	narg = callp->sy_narg & SYF_ARGMASK;
395
396	if (narg > n * sizeof(register_t)) {
397		bcopy(params, args, n * sizeof(register_t));
398		error = copyin(MOREARGS(frame->fixreg[1]), args + n,
399			narg - n * sizeof(register_t));
400		if (error) {
401#ifdef	KTRACE
402			/* Can't get all the arguments! */
403			if (KTRPOINT(p, KTR_SYSCALL))
404				ktrsyscall(p->p_tracep, code, narg, args);
405#endif
406			goto bad;
407		}
408		params = (caddr_t)args;
409	}
410
411	/*
412	 * Try to run the syscall without Giant if the syscall is MP safe.
413	 */
414	if ((callp->sy_narg & SYF_MPSAFE) == 0)
415		mtx_lock(&Giant);
416
417#ifdef	KTRACE
418	if (KTRPOINT(p, KTR_SYSCALL))
419		ktrsyscall(p->p_tracep, code, narg, params);
420#endif
421	td->td_retval[0] = 0;
422	td->td_retval[1] = frame->fixreg[FIRSTARG + 1];
423
424	STOPEVENT(p, S_SCE, narg);
425
426	error = (*callp->sy_call)(td, params);
427	switch (error) {
428	case 0:
429		frame->fixreg[FIRSTARG] = td->td_retval[0];
430		frame->fixreg[FIRSTARG + 1] = td->td_retval[1];
431		/* XXX: Magic number */
432		frame->cr &= ~0x10000000;
433		break;
434	case ERESTART:
435		/*
436		 * Set user's pc back to redo the system call.
437		 */
438		frame->srr0 -= 4;
439		break;
440	case EJUSTRETURN:
441		/* nothing to do */
442		break;
443	default:
444bad:
445		if (p->p_sysent->sv_errsize) {
446			if (error >= p->p_sysent->sv_errsize)
447				error = -1;	/* XXX */
448			else
449				error = p->p_sysent->sv_errtbl[error];
450		}
451		frame->fixreg[FIRSTARG] = error;
452		/* XXX: Magic number: Carry Flag Equivalent? */
453		frame->cr |= 0x10000000;
454		break;
455	}
456
457
458#ifdef	KTRACE
459	if (KTRPOINT(p, KTR_SYSRET))
460		ktrsysret(p->p_tracep, code, error, td->td_retval[0]);
461#endif
462
463	if ((callp->sy_narg & SYF_MPSAFE) == 0)
464		mtx_unlock(&Giant);
465
466	/*
467	 * Does the comment in the i386 code about errno apply here?
468	 */
469	STOPEVENT(p, S_SCX, code);
470
471#ifdef WITNESS
472	if (witness_list(td)) {
473		panic("system call %s returning with mutex(s) held\n",
474		    syscallnames[code]);
475	}
476#endif
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_READ | 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	mtx_lock(&Giant);
525	if (map != kernel_map) {
526		/*
527		 * Keep swapout from messing with us during this
528		 *	critical time.
529		 */
530		PROC_LOCK(p);
531		++p->p_lock;
532		PROC_UNLOCK(p);
533
534		/* Fault in the user page: */
535		rv = vm_fault(map, va, ftype,
536		      (ftype & VM_PROT_WRITE) ? VM_FAULT_DIRTY
537					      : VM_FAULT_NORMAL);
538
539		PROC_LOCK(p);
540		--p->p_lock;
541		PROC_UNLOCK(p);
542	} else {
543		/*
544		 * Don't have to worry about process locking or stacks in the
545		 * kernel.
546		 */
547		rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL);
548	}
549	mtx_unlock(&Giant);
550
551	if (rv == KERN_SUCCESS)
552		return (0);
553
554	if (!user && handle_onfault(frame))
555		return (0);
556
557	return (SIGSEGV);
558}
559
560static __inline void
561setusr(u_int content)
562{
563	__asm __volatile ("isync; mtsr %0,%1; isync"
564		      :: "n"(USER_SR), "r"(content));
565}
566
567int
568badaddr(void *addr, size_t size)
569{
570	return (badaddr_read(addr, size, NULL));
571}
572
573int
574badaddr_read(void *addr, size_t size, int *rptr)
575{
576	struct thread	*td;
577	faultbuf	env;
578	int		x;
579
580	/* Get rid of any stale machine checks that have been waiting.  */
581	__asm __volatile ("sync; isync");
582
583	td = PCPU_GET(curthread);
584
585	if (setfault(env)) {
586		td->td_pcb->pcb_onfault = 0;
587		__asm __volatile ("sync");
588		return 1;
589	}
590
591	__asm __volatile ("sync");
592
593	switch (size) {
594	case 1:
595		x = *(volatile int8_t *)addr;
596		break;
597	case 2:
598		x = *(volatile int16_t *)addr;
599		break;
600	case 4:
601		x = *(volatile int32_t *)addr;
602		break;
603	default:
604		panic("badaddr: invalid size (%d)", size);
605	}
606
607	/* Make sure we took the machine check, if we caused one. */
608	__asm __volatile ("sync; isync");
609
610	td->td_pcb->pcb_onfault = 0;
611	__asm __volatile ("sync");	/* To be sure. */
612
613	/* Use the value to avoid reorder. */
614	if (rptr)
615		*rptr = x;
616
617	return (0);
618}
619
620/*
621 * For now, this only deals with the particular unaligned access case
622 * that gcc tends to generate.  Eventually it should handle all of the
623 * possibilities that can happen on a 32-bit PowerPC in big-endian mode.
624 */
625
626static int
627fix_unaligned(struct thread *td, struct trapframe *frame)
628{
629	struct thread	*fputhread;
630	int		indicator, reg;
631	double		*fpr;
632
633	indicator = EXC_ALI_OPCODE_INDICATOR(frame->dsisr);
634
635	switch (indicator) {
636	case EXC_ALI_LFD:
637	case EXC_ALI_STFD:
638		reg = EXC_ALI_RST(frame->dsisr);
639		fpr = &td->td_pcb->pcb_fpu.fpr[reg];
640		fputhread = PCPU_GET(fputhread);
641
642		/* Juggle the FPU to ensure that we've initialized
643		 * the FPRs, and that their current state is in
644		 * the PCB.
645		 */
646		if (fputhread != td) {
647			if (fputhread)
648				save_fpu(fputhread);
649			enable_fpu(td);
650		}
651		save_fpu(td);
652
653		if (indicator == EXC_ALI_LFD) {
654			if (copyin((void *)frame->dar, fpr,
655			    sizeof(double)) != 0)
656				return -1;
657			enable_fpu(td);
658		} else {
659			if (copyout(fpr, (void *)frame->dar,
660			    sizeof(double)) != 0)
661				return -1;
662		}
663		return 0;
664		break;
665	}
666
667	return -1;
668}
669