trap.c revision 188860 
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 188860 2009-02-20 17:48:40Z nwhitehorn $");
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/ptrace.h>
47#include <sys/reboot.h>
48#include <sys/syscall.h>
49#include <sys/sysent.h>
50#include <sys/systm.h>
51#include <sys/uio.h>
52#include <sys/signalvar.h>
53#ifdef KTRACE
54#include <sys/ktrace.h>
55#endif
56#include <sys/vmmeter.h>
57
58#include <security/audit/audit.h>
59
60#include <vm/vm.h>
61#include <vm/pmap.h>
62#include <vm/vm_extern.h>
63#include <vm/vm_param.h>
64#include <vm/vm_kern.h>
65#include <vm/vm_map.h>
66#include <vm/vm_page.h>
67
68#include <machine/altivec.h>
69#include <machine/cpu.h>
70#include <machine/db_machdep.h>
71#include <machine/fpu.h>
72#include <machine/frame.h>
73#include <machine/pcb.h>
74#include <machine/pmap.h>
75#include <machine/psl.h>
76#include <machine/trap.h>
77#include <machine/spr.h>
78#include <machine/sr.h>
79
80static void	trap_fatal(struct trapframe *frame);
81static void	printtrap(u_int vector, struct trapframe *frame, int isfatal,
82		    int user);
83static int	trap_pfault(struct trapframe *frame, int user);
84static int	fix_unaligned(struct thread *td, struct trapframe *frame);
85static int	handle_onfault(struct trapframe *frame);
86static void	syscall(struct trapframe *frame);
87
88static __inline void	setusr(u_int);
89
90int	setfault(faultbuf);		/* defined in locore.S */
91
92/* Why are these not defined in a header? */
93int	badaddr(void *, size_t);
94int	badaddr_read(void *, size_t, int *);
95
96extern char	*syscallnames[];
97
98struct powerpc_exception {
99	u_int	vector;
100	char	*name;
101};
102
103static struct powerpc_exception powerpc_exceptions[] = {
104	{ 0x0100, "system reset" },
105	{ 0x0200, "machine check" },
106	{ 0x0300, "data storage interrupt" },
107	{ 0x0400, "instruction storage interrupt" },
108	{ 0x0500, "external interrupt" },
109	{ 0x0600, "alignment" },
110	{ 0x0700, "program" },
111	{ 0x0800, "floating-point unavailable" },
112	{ 0x0900, "decrementer" },
113	{ 0x0c00, "system call" },
114	{ 0x0d00, "trace" },
115	{ 0x0e00, "floating-point assist" },
116	{ 0x0f00, "performance monitoring" },
117	{ 0x0f20, "altivec unavailable" },
118	{ 0x1000, "instruction tlb miss" },
119	{ 0x1100, "data load tlb miss" },
120	{ 0x1200, "data store tlb miss" },
121	{ 0x1300, "instruction breakpoint" },
122	{ 0x1400, "system management" },
123	{ 0x1600, "altivec assist" },
124	{ 0x1700, "thermal management" },
125	{ 0x2000, "run mode/trace" },
126	{ 0x3000, NULL }
127};
128
129static const char *
130trapname(u_int vector)
131{
132	struct	powerpc_exception *pe;
133
134	for (pe = powerpc_exceptions; pe->vector != 0x3000; pe++) {
135		if (pe->vector == vector)
136			return (pe->name);
137	}
138
139	return ("unknown");
140}
141
142void
143trap(struct trapframe *frame)
144{
145	struct thread	*td;
146	struct proc	*p;
147	int		sig, type, user;
148	u_int		ucode;
149	ksiginfo_t	ksi;
150
151	PCPU_INC(cnt.v_trap);
152
153	td = PCPU_GET(curthread);
154	p = td->td_proc;
155
156	type = ucode = frame->exc;
157	sig = 0;
158	user = frame->srr1 & PSL_PR;
159
160	CTR3(KTR_TRAP, "trap: %s type=%s (%s)", td->td_name,
161	    trapname(type), user ? "user" : "kernel");
162
163	if (user) {
164		td->td_pticks = 0;
165		td->td_frame = frame;
166		if (td->td_ucred != p->p_ucred)
167			cred_update_thread(td);
168
169		/* User Mode Traps */
170		switch (type) {
171		case EXC_RUNMODETRC:
172		case EXC_TRC:
173			frame->srr1 &= ~PSL_SE;
174			sig = SIGTRAP;
175			break;
176
177		case EXC_DSI:
178		case EXC_ISI:
179			sig = trap_pfault(frame, 1);
180			break;
181
182		case EXC_SC:
183			syscall(frame);
184			break;
185
186		case EXC_FPU:
187			KASSERT((td->td_pcb->pcb_flags & PCB_FPU) != PCB_FPU,
188			    ("FPU already enabled for thread"));
189			enable_fpu(td);
190			break;
191
192		case EXC_VEC:
193			KASSERT((td->td_pcb->pcb_flags & PCB_VEC) != PCB_VEC,
194			    ("Altivec already enabled for thread"));
195			enable_vec(td);
196			break;
197
198		case EXC_VECAST:
199			printf("Vector assist exception!\n");
200			sig = SIGILL;
201			break;
202
203		case EXC_ALI:
204			if (fix_unaligned(td, frame) != 0)
205				sig = SIGBUS;
206			else
207				frame->srr0 += 4;
208			break;
209
210		case EXC_PGM:
211			/* XXX temporarily */
212			/* XXX: Magic Number? */
213			if (frame->srr1 & 0x0002000)
214				sig = SIGTRAP;
215 			else
216				sig = SIGILL;
217			break;
218
219		default:
220			trap_fatal(frame);
221		}
222	} else {
223		/* Kernel Mode Traps */
224
225		KASSERT(cold || td->td_ucred != NULL,
226		    ("kernel trap doesn't have ucred"));
227		switch (type) {
228		case EXC_DSI:
229			if (trap_pfault(frame, 0) == 0)
230 				return;
231			break;
232		case EXC_MCHK:
233			if (handle_onfault(frame))
234 				return;
235			break;
236		default:
237			break;
238		}
239		trap_fatal(frame);
240	}
241
242#ifdef	ALTIVEC
243	if (td != PCPU_GET(vecthread) ||
244	    td->td_pcb->pcb_veccpu != PCPU_GET(cpuid))
245		frame->srr1 &= ~PSL_VEC;
246#endif /* ALTIVEC */
247
248	if (sig != 0) {
249		if (p->p_sysent->sv_transtrap != NULL)
250			sig = (p->p_sysent->sv_transtrap)(sig, type);
251		ksiginfo_init_trap(&ksi);
252		ksi.ksi_signo = sig;
253		ksi.ksi_code = (int) ucode; /* XXX, not POSIX */
254		/* ksi.ksi_addr = ? */
255		ksi.ksi_trapno = type;
256		trapsignal(td, &ksi);
257	}
258
259	userret(td, frame);
260	mtx_assert(&Giant, MA_NOTOWNED);
261}
262
263static void
264trap_fatal(struct trapframe *frame)
265{
266
267	printtrap(frame->exc, frame, 1, (frame->srr1 & PSL_PR));
268#ifdef KDB
269	if ((debugger_on_panic || kdb_active) &&
270	    kdb_trap(frame->exc, 0, frame))
271		return;
272#endif
273	panic("%s trap", trapname(frame->exc));
274}
275
276static void
277printtrap(u_int vector, struct trapframe *frame, int isfatal, int user)
278{
279
280	printf("\n");
281	printf("%s %s trap:\n", isfatal ? "fatal" : "handled",
282	    user ? "user" : "kernel");
283	printf("\n");
284	printf("   exception       = 0x%x (%s)\n", vector >> 8,
285	    trapname(vector));
286	switch (vector) {
287	case EXC_DSI:
288		printf("   virtual address = 0x%x\n", frame->cpu.aim.dar);
289		break;
290	case EXC_ISI:
291		printf("   virtual address = 0x%x\n", frame->srr0);
292		break;
293	}
294	printf("   srr0            = 0x%x\n", frame->srr0);
295	printf("   srr1            = 0x%x\n", frame->srr1);
296	printf("   lr              = 0x%x\n", frame->lr);
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_name);
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_INC(cnt.v_syscall);
345
346	code = frame->fixreg[0];
347	params = (caddr_t)(frame->fixreg + FIRSTARG);
348	n = NARGREG;
349
350	if (p->p_sysent->sv_prepsyscall) {
351		/*
352		 * The prep code is MP aware.
353		 */
354		(*p->p_sysent->sv_prepsyscall)(frame, args, &code, &params);
355	} else if (code == SYS_syscall) {
356		/*
357		 * code is first argument,
358		 * followed by actual args.
359		 */
360		code = *(u_int *) params;
361		params += sizeof(register_t);
362		n -= 1;
363	} else if (code == SYS___syscall) {
364		/*
365		 * Like syscall, but code is a quad,
366		 * so as to maintain quad alignment
367		 * for the rest of the args.
368		 */
369		params += sizeof(register_t);
370		code = *(u_int *) params;
371		params += sizeof(register_t);
372		n -= 2;
373	}
374
375 	if (p->p_sysent->sv_mask)
376 		code &= p->p_sysent->sv_mask;
377
378 	if (code >= p->p_sysent->sv_size)
379 		callp = &p->p_sysent->sv_table[0];
380  	else
381 		callp = &p->p_sysent->sv_table[code];
382
383	narg = callp->sy_narg;
384
385	if (narg > n) {
386		bcopy(params, args, n * sizeof(register_t));
387		error = copyin(MOREARGS(frame->fixreg[1]), args + n,
388			       (narg - n) * sizeof(register_t));
389		params = (caddr_t)args;
390	} else
391		error = 0;
392
393	CTR5(KTR_SYSC, "syscall: p=%s %s(%x %x %x)", td->td_name,
394	     syscallnames[code],
395	     frame->fixreg[FIRSTARG],
396	     frame->fixreg[FIRSTARG+1],
397	     frame->fixreg[FIRSTARG+2]);
398
399#ifdef	KTRACE
400	if (KTRPOINT(td, KTR_SYSCALL))
401		ktrsyscall(code, narg, (register_t *)params);
402#endif
403
404	td->td_syscalls++;
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		PTRACESTOP_SC(p, td, S_PT_SCE);
413
414		AUDIT_SYSCALL_ENTER(code, td);
415		error = (*callp->sy_call)(td, params);
416		AUDIT_SYSCALL_EXIT(error, td);
417
418		CTR3(KTR_SYSC, "syscall: p=%s %s ret=%x", td->td_name,
419		     syscallnames[code], td->td_retval[0]);
420	}
421	switch (error) {
422	case 0:
423		if (frame->fixreg[0] == SYS___syscall &&
424		    code != SYS_freebsd6_lseek && code != SYS_lseek) {
425			/*
426			 * 64-bit return, 32-bit syscall. Fixup byte order
427			 */
428			frame->fixreg[FIRSTARG] = 0;
429			frame->fixreg[FIRSTARG + 1] = td->td_retval[0];
430		} else {
431			frame->fixreg[FIRSTARG] = td->td_retval[0];
432			frame->fixreg[FIRSTARG + 1] = td->td_retval[1];
433		}
434		/* XXX: Magic number */
435		frame->cr &= ~0x10000000;
436		break;
437	case ERESTART:
438		/*
439		 * Set user's pc back to redo the system call.
440		 */
441		frame->srr0 -= 4;
442		break;
443	case EJUSTRETURN:
444		/* nothing to do */
445		break;
446	default:
447		if (p->p_sysent->sv_errsize) {
448			if (error >= p->p_sysent->sv_errsize)
449				error = -1;	/* XXX */
450			else
451				error = p->p_sysent->sv_errtbl[error];
452		}
453		frame->fixreg[FIRSTARG] = error;
454		/* XXX: Magic number: Carry Flag Equivalent? */
455		frame->cr |= 0x10000000;
456		break;
457	}
458
459	/*
460	 * Check for misbehavior.
461	 */
462	WITNESS_WARN(WARN_PANIC, NULL, "System call %s returning",
463	    (code >= 0 && code < SYS_MAXSYSCALL) ? syscallnames[code] : "???");
464	KASSERT(td->td_critnest == 0,
465	    ("System call %s returning in a critical section",
466	    (code >= 0 && code < SYS_MAXSYSCALL) ? syscallnames[code] : "???"));
467	KASSERT(td->td_locks == 0,
468	    ("System call %s returning with %d locks held",
469	    (code >= 0 && code < SYS_MAXSYSCALL) ? syscallnames[code] : "???",
470	    td->td_locks));
471
472#ifdef	KTRACE
473	if (KTRPOINT(td, KTR_SYSRET))
474		ktrsysret(code, error, td->td_retval[0]);
475#endif
476
477	/*
478	 * Does the comment in the i386 code about errno apply here?
479	 */
480	STOPEVENT(p, S_SCX, code);
481
482	PTRACESTOP_SC(p, td, S_PT_SCX);
483}
484
485static int
486trap_pfault(struct trapframe *frame, int user)
487{
488	vm_offset_t	eva, va;
489	struct		thread *td;
490	struct		proc *p;
491	vm_map_t	map;
492	vm_prot_t	ftype;
493	int		rv;
494	u_int		user_sr;
495
496	td = curthread;
497	p = td->td_proc;
498	if (frame->exc == EXC_ISI) {
499		eva = frame->srr0;
500		ftype = VM_PROT_READ | VM_PROT_EXECUTE;
501	} else {
502		eva = frame->cpu.aim.dar;
503		if (frame->cpu.aim.dsisr & DSISR_STORE)
504			ftype = VM_PROT_WRITE;
505		else
506			ftype = VM_PROT_READ;
507	}
508
509	if (user) {
510		map = &p->p_vmspace->vm_map;
511	} else {
512		if ((eva >> ADDR_SR_SHFT) == USER_SR) {
513			if (p->p_vmspace == NULL)
514				return (SIGSEGV);
515
516			__asm ("mfsr %0, %1"
517			    : "=r"(user_sr)
518			    : "K"(USER_SR));
519			eva &= ADDR_PIDX | ADDR_POFF;
520			eva |= user_sr << ADDR_SR_SHFT;
521			map = &p->p_vmspace->vm_map;
522		} else {
523			map = kernel_map;
524		}
525	}
526	va = trunc_page(eva);
527
528	if (map != kernel_map) {
529		/*
530		 * Keep swapout from messing with us during this
531		 *	critical time.
532		 */
533		PROC_LOCK(p);
534		++p->p_lock;
535		PROC_UNLOCK(p);
536
537		/* Fault in the user page: */
538		rv = vm_fault(map, va, ftype,
539		      (ftype & VM_PROT_WRITE) ? VM_FAULT_DIRTY
540					      : VM_FAULT_NORMAL);
541
542		PROC_LOCK(p);
543		--p->p_lock;
544		PROC_UNLOCK(p);
545	} else {
546		/*
547		 * Don't have to worry about process locking or stacks in the
548		 * kernel.
549		 */
550		rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL);
551	}
552
553	if (rv == KERN_SUCCESS)
554		return (0);
555
556	if (!user && handle_onfault(frame))
557		return (0);
558
559	return (SIGSEGV);
560}
561
562static __inline void
563setusr(u_int content)
564{
565	__asm __volatile ("isync; mtsr %0,%1; isync"
566		      :: "n"(USER_SR), "r"(content));
567}
568
569int
570badaddr(void *addr, size_t size)
571{
572	return (badaddr_read(addr, size, NULL));
573}
574
575int
576badaddr_read(void *addr, size_t size, int *rptr)
577{
578	struct thread	*td;
579	faultbuf	env;
580	int		x;
581
582	/* Get rid of any stale machine checks that have been waiting.  */
583	__asm __volatile ("sync; isync");
584
585	td = PCPU_GET(curthread);
586
587	if (setfault(env)) {
588		td->td_pcb->pcb_onfault = 0;
589		__asm __volatile ("sync");
590		return 1;
591	}
592
593	__asm __volatile ("sync");
594
595	switch (size) {
596	case 1:
597		x = *(volatile int8_t *)addr;
598		break;
599	case 2:
600		x = *(volatile int16_t *)addr;
601		break;
602	case 4:
603		x = *(volatile int32_t *)addr;
604		break;
605	default:
606		panic("badaddr: invalid size (%d)", size);
607	}
608
609	/* Make sure we took the machine check, if we caused one. */
610	__asm __volatile ("sync; isync");
611
612	td->td_pcb->pcb_onfault = 0;
613	__asm __volatile ("sync");	/* To be sure. */
614
615	/* Use the value to avoid reorder. */
616	if (rptr)
617		*rptr = x;
618
619	return (0);
620}
621
622/*
623 * For now, this only deals with the particular unaligned access case
624 * that gcc tends to generate.  Eventually it should handle all of the
625 * possibilities that can happen on a 32-bit PowerPC in big-endian mode.
626 */
627
628static int
629fix_unaligned(struct thread *td, struct trapframe *frame)
630{
631	struct thread	*fputhread;
632	int		indicator, reg;
633	double		*fpr;
634
635	indicator = EXC_ALI_OPCODE_INDICATOR(frame->cpu.aim.dsisr);
636
637	switch (indicator) {
638	case EXC_ALI_LFD:
639	case EXC_ALI_STFD:
640		reg = EXC_ALI_RST(frame->cpu.aim.dsisr);
641		fpr = &td->td_pcb->pcb_fpu.fpr[reg];
642		fputhread = PCPU_GET(fputhread);
643
644		/* Juggle the FPU to ensure that we've initialized
645		 * the FPRs, and that their current state is in
646		 * the PCB.
647		 */
648		if (fputhread != td) {
649			if (fputhread)
650				save_fpu(fputhread);
651			enable_fpu(td);
652		}
653		save_fpu(td);
654
655		if (indicator == EXC_ALI_LFD) {
656			if (copyin((void *)frame->cpu.aim.dar, fpr,
657			    sizeof(double)) != 0)
658				return -1;
659			enable_fpu(td);
660		} else {
661			if (copyout(fpr, (void *)frame->cpu.aim.dar,
662			    sizeof(double)) != 0)
663				return -1;
664		}
665		return 0;
666		break;
667	}
668
669	return -1;
670}
671