trap.c revision 113038 
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 113038 2003-04-03 21:36:33Z obrien $");
36
37#include "opt_ddb.h"
38#include "opt_ktrace.h"
39
40#include <sys/param.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/user.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
76#include <ddb/ddb.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;
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_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			KASSERT((td->td_pcb->pcb_flags & PCB_FPU) != PCB_FPU,
194			    ("FPU already enabled for thread"));
195			enable_fpu(td);
196			break;
197
198#ifdef	ALTIVEC
199		case EXC_VEC:
200			if ((vecthread = PCPU_GET(vecthread)) != NULL) {
201				KASSERT(vecthread != td,
202				    ("altivec already enabled"));
203				save_vec(vecthread);
204			}
205			PCPU_SET(vecthread, td);
206			td->td_pcb->pcb_veccpu = PCPU_GET(cpuid);
207			enable_vec(td);
208			frame->srr1 |= PSL_VEC;
209			break;
210#endif /* ALTIVEC */
211
212		case EXC_ALI:
213			if (fix_unaligned(td, frame) != 0)
214				sig = SIGBUS;
215			else
216				frame->srr0 += 4;
217			break;
218
219		case EXC_PGM:
220			/* XXX temporarily */
221			/* XXX: Magic Number? */
222			if (frame->srr1 & 0x0002000)
223				sig = SIGTRAP;
224 			else
225				sig = SIGILL;
226			break;
227
228		default:
229			trap_fatal(frame);
230		}
231	} else {
232		/* Kernel Mode Traps */
233
234		KASSERT(cold || td->td_ucred != NULL,
235		    ("kernel trap doesn't have ucred"));
236		switch (type) {
237		case EXC_DSI:
238			if (trap_pfault(frame, 0) == 0)
239 				return;
240			break;
241		case EXC_MCHK:
242			if (handle_onfault(frame))
243 				return;
244			break;
245		default:
246			trap_fatal(frame);
247		}
248	}
249
250#ifdef	ALTIVEC
251	if (td != PCPU_GET(vecthread) ||
252	    td->td_pcb->pcb_veccpu != PCPU_GET(cpuid))
253		frame->srr1 &= ~PSL_VEC;
254#endif /* ALTIVEC */
255
256	if (sig != 0) {
257		if (p->p_sysent->sv_transtrap != NULL)
258			sig = (p->p_sysent->sv_transtrap)(sig, type);
259		trapsignal(td, sig, ucode);
260	}
261
262	userret(td, frame, sticks);
263	mtx_assert(&Giant, MA_NOTOWNED);
264#ifdef	DIAGNOSTIC
265	cred_free_thread(td);
266#endif	/* DIAGNOSTIC */
267}
268
269static void
270trap_fatal(struct trapframe *frame)
271{
272
273	printtrap(frame->exc, frame, 1, (frame->srr1 & PSL_PR));
274#ifdef DDB
275	if ((debugger_on_panic || db_active) && kdb_trap(frame->exc, frame))
276		return;
277#endif
278	panic("%s trap", trapname(frame->exc));
279}
280
281static void
282printtrap(u_int vector, struct trapframe *frame, int isfatal, int user)
283{
284
285	printf("\n");
286	printf("%s %s trap:\n", isfatal ? "fatal" : "handled",
287	    user ? "user" : "kernel");
288	printf("\n");
289	printf("   exception       = 0x%x (%s)\n", vector >> 8,
290	    trapname(vector));
291	switch (vector) {
292	case EXC_DSI:
293		printf("   virtual address = 0x%x\n", frame->dar);
294		break;
295	case EXC_ISI:
296		printf("   virtual address = 0x%x\n", frame->srr0);
297		break;
298	}
299	printf("   srr0            = 0x%x\n", frame->srr0);
300	printf("   srr1            = 0x%x\n", frame->srr1);
301	printf("   curthread       = %p\n", curthread);
302	if (curthread != NULL)
303		printf("          pid = %d, comm = %s\n",
304		    curthread->td_proc->p_pid, curthread->td_proc->p_comm);
305	printf("\n");
306}
307
308/*
309 * Handles a fatal fault when we have onfault state to recover.  Returns
310 * non-zero if there was onfault recovery state available.
311 */
312static int
313handle_onfault(struct trapframe *frame)
314{
315	struct		thread *td;
316	faultbuf	*fb;
317
318	td = curthread;
319	fb = td->td_pcb->pcb_onfault;
320	if (fb != NULL) {
321		frame->srr0 = (*fb)[0];
322		frame->fixreg[1] = (*fb)[1];
323		frame->fixreg[2] = (*fb)[2];
324		frame->cr = (*fb)[3];
325		bcopy(&(*fb)[4], &frame->fixreg[13],
326		    19 * sizeof(register_t));
327		return (1);
328	}
329	return (0);
330}
331
332void
333syscall(struct trapframe *frame)
334{
335	caddr_t		params;
336	struct		sysent *callp;
337	struct		thread *td;
338	struct		proc *p;
339	int		error, n;
340	size_t		narg;
341	register_t	args[10];
342	u_int		code;
343
344	td = PCPU_GET(curthread);
345	p = td->td_proc;
346
347	atomic_add_int(&cnt.v_syscall, 1);
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#ifdef	KTRACE
397	if (KTRPOINT(td, KTR_SYSCALL))
398		ktrsyscall(code, narg, (register_t *)params);
399#endif
400	/*
401	 * Try to run the syscall without Giant if the syscall is MP safe.
402	 */
403	if ((callp->sy_narg & SYF_MPSAFE) == 0)
404		mtx_lock(&Giant);
405
406	if (error == 0) {
407		td->td_retval[0] = 0;
408		td->td_retval[1] = frame->fixreg[FIRSTARG + 1];
409
410		STOPEVENT(p, S_SCE, narg);
411
412		error = (*callp->sy_call)(td, params);
413	}
414	switch (error) {
415	case 0:
416		if ((frame->fixreg[0] == SYS___syscall) &&
417		    (code != SYS_lseek)) {
418			/*
419			 * 64-bit return, 32-bit syscall. Fixup byte order
420			 */
421			frame->fixreg[FIRSTARG] = 0;
422			frame->fixreg[FIRSTARG + 1] = td->td_retval[0];
423		} else {
424			frame->fixreg[FIRSTARG] = td->td_retval[0];
425			frame->fixreg[FIRSTARG + 1] = td->td_retval[1];
426		}
427		/* XXX: Magic number */
428		frame->cr &= ~0x10000000;
429		break;
430	case ERESTART:
431		/*
432		 * Set user's pc back to redo the system call.
433		 */
434		frame->srr0 -= 4;
435		break;
436	case EJUSTRETURN:
437		/* nothing to do */
438		break;
439	default:
440		if (p->p_sysent->sv_errsize) {
441			if (error >= p->p_sysent->sv_errsize)
442				error = -1;	/* XXX */
443			else
444				error = p->p_sysent->sv_errtbl[error];
445		}
446		frame->fixreg[FIRSTARG] = error;
447		/* XXX: Magic number: Carry Flag Equivalent? */
448		frame->cr |= 0x10000000;
449		break;
450	}
451
452
453	if ((callp->sy_narg & SYF_MPSAFE) == 0)
454		mtx_unlock(&Giant);
455
456#ifdef	KTRACE
457	if (KTRPOINT(td, KTR_SYSRET))
458		ktrsysret(code, error, td->td_retval[0]);
459#endif
460
461	/*
462	 * Does the comment in the i386 code about errno apply here?
463	 */
464	STOPEVENT(p, S_SCX, code);
465
466	WITNESS_WARN(WARN_PANIC, NULL, "System call %s returning",
467	    syscallnames[code]);
468	mtx_assert(&sched_lock, MA_NOTOWNED);
469	mtx_assert(&Giant, MA_NOTOWNED);
470}
471
472static int
473trap_pfault(struct trapframe *frame, int user)
474{
475	vm_offset_t	eva, va;
476	struct		thread *td;
477	struct		proc *p;
478	vm_map_t	map;
479	vm_prot_t	ftype;
480	int		rv;
481	u_int		user_sr;
482
483	td = curthread;
484	p = td->td_proc;
485	if (frame->exc == EXC_ISI) {
486		eva = frame->srr0;
487		ftype = VM_PROT_READ | VM_PROT_EXECUTE;
488	} else {
489		eva = frame->dar;
490		if (frame->dsisr & DSISR_STORE)
491			ftype = VM_PROT_WRITE;
492		else
493			ftype = VM_PROT_READ;
494	}
495
496	if (user) {
497		map = &p->p_vmspace->vm_map;
498	} else {
499		if ((eva >> ADDR_SR_SHFT) == USER_SR) {
500			if (p->p_vmspace == NULL)
501				return (SIGSEGV);
502
503			__asm ("mfsr %0, %1"
504			    : "=r"(user_sr)
505			    : "K"(USER_SR));
506			eva &= ADDR_PIDX | ADDR_POFF;
507			eva |= user_sr << ADDR_SR_SHFT;
508			map = &p->p_vmspace->vm_map;
509		} else {
510			map = kernel_map;
511		}
512	}
513	va = trunc_page(eva);
514
515	mtx_lock(&Giant);
516	if (map != kernel_map) {
517		/*
518		 * Keep swapout from messing with us during this
519		 *	critical time.
520		 */
521		PROC_LOCK(p);
522		++p->p_lock;
523		PROC_UNLOCK(p);
524
525		/* Fault in the user page: */
526		rv = vm_fault(map, va, ftype,
527		      (ftype & VM_PROT_WRITE) ? VM_FAULT_DIRTY
528					      : VM_FAULT_NORMAL);
529
530		PROC_LOCK(p);
531		--p->p_lock;
532		PROC_UNLOCK(p);
533	} else {
534		/*
535		 * Don't have to worry about process locking or stacks in the
536		 * kernel.
537		 */
538		rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL);
539	}
540	mtx_unlock(&Giant);
541
542	if (rv == KERN_SUCCESS)
543		return (0);
544
545	if (!user && handle_onfault(frame))
546		return (0);
547
548	return (SIGSEGV);
549}
550
551static __inline void
552setusr(u_int content)
553{
554	__asm __volatile ("isync; mtsr %0,%1; isync"
555		      :: "n"(USER_SR), "r"(content));
556}
557
558int
559badaddr(void *addr, size_t size)
560{
561	return (badaddr_read(addr, size, NULL));
562}
563
564int
565badaddr_read(void *addr, size_t size, int *rptr)
566{
567	struct thread	*td;
568	faultbuf	env;
569	int		x;
570
571	/* Get rid of any stale machine checks that have been waiting.  */
572	__asm __volatile ("sync; isync");
573
574	td = PCPU_GET(curthread);
575
576	if (setfault(env)) {
577		td->td_pcb->pcb_onfault = 0;
578		__asm __volatile ("sync");
579		return 1;
580	}
581
582	__asm __volatile ("sync");
583
584	switch (size) {
585	case 1:
586		x = *(volatile int8_t *)addr;
587		break;
588	case 2:
589		x = *(volatile int16_t *)addr;
590		break;
591	case 4:
592		x = *(volatile int32_t *)addr;
593		break;
594	default:
595		panic("badaddr: invalid size (%d)", size);
596	}
597
598	/* Make sure we took the machine check, if we caused one. */
599	__asm __volatile ("sync; isync");
600
601	td->td_pcb->pcb_onfault = 0;
602	__asm __volatile ("sync");	/* To be sure. */
603
604	/* Use the value to avoid reorder. */
605	if (rptr)
606		*rptr = x;
607
608	return (0);
609}
610
611/*
612 * For now, this only deals with the particular unaligned access case
613 * that gcc tends to generate.  Eventually it should handle all of the
614 * possibilities that can happen on a 32-bit PowerPC in big-endian mode.
615 */
616
617static int
618fix_unaligned(struct thread *td, struct trapframe *frame)
619{
620	struct thread	*fputhread;
621	int		indicator, reg;
622	double		*fpr;
623
624	indicator = EXC_ALI_OPCODE_INDICATOR(frame->dsisr);
625
626	switch (indicator) {
627	case EXC_ALI_LFD:
628	case EXC_ALI_STFD:
629		reg = EXC_ALI_RST(frame->dsisr);
630		fpr = &td->td_pcb->pcb_fpu.fpr[reg];
631		fputhread = PCPU_GET(fputhread);
632
633		/* Juggle the FPU to ensure that we've initialized
634		 * the FPRs, and that their current state is in
635		 * the PCB.
636		 */
637		if (fputhread != td) {
638			if (fputhread)
639				save_fpu(fputhread);
640			enable_fpu(td);
641		}
642		save_fpu(td);
643
644		if (indicator == EXC_ALI_LFD) {
645			if (copyin((void *)frame->dar, fpr,
646			    sizeof(double)) != 0)
647				return -1;
648			enable_fpu(td);
649		} else {
650			if (copyout(fpr, (void *)frame->dar,
651			    sizeof(double)) != 0)
652				return -1;
653		}
654		return 0;
655		break;
656	}
657
658	return -1;
659}
660