trap.c revision 204197 
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 204197 2010-02-22 14:17:23Z 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	ppc_instr_emulate(struct trapframe *frame);
86static int	handle_onfault(struct trapframe *frame);
87static void	syscall(struct trapframe *frame);
88
89int	setfault(faultbuf);		/* defined in locore.S */
90
91/* Why are these not defined in a header? */
92int	badaddr(void *, size_t);
93int	badaddr_read(void *, size_t, int *);
94
95extern char	*syscallnames[];
96
97struct powerpc_exception {
98	u_int	vector;
99	char	*name;
100};
101
102static struct powerpc_exception powerpc_exceptions[] = {
103	{ 0x0100, "system reset" },
104	{ 0x0200, "machine check" },
105	{ 0x0300, "data storage interrupt" },
106	{ 0x0400, "instruction storage interrupt" },
107	{ 0x0500, "external interrupt" },
108	{ 0x0600, "alignment" },
109	{ 0x0700, "program" },
110	{ 0x0800, "floating-point unavailable" },
111	{ 0x0900, "decrementer" },
112	{ 0x0c00, "system call" },
113	{ 0x0d00, "trace" },
114	{ 0x0e00, "floating-point assist" },
115	{ 0x0f00, "performance monitoring" },
116	{ 0x0f20, "altivec unavailable" },
117	{ 0x1000, "instruction tlb miss" },
118	{ 0x1100, "data load tlb miss" },
119	{ 0x1200, "data store tlb miss" },
120	{ 0x1300, "instruction breakpoint" },
121	{ 0x1400, "system management" },
122	{ 0x1600, "altivec assist" },
123	{ 0x1700, "thermal management" },
124	{ 0x2000, "run mode/trace" },
125	{ 0x3000, NULL }
126};
127
128static const char *
129trapname(u_int vector)
130{
131	struct	powerpc_exception *pe;
132
133	for (pe = powerpc_exceptions; pe->vector != 0x3000; pe++) {
134		if (pe->vector == vector)
135			return (pe->name);
136	}
137
138	return ("unknown");
139}
140
141void
142trap(struct trapframe *frame)
143{
144	struct thread	*td;
145	struct proc	*p;
146	int		sig, type, user;
147	u_int		ucode;
148	ksiginfo_t	ksi;
149
150	PCPU_INC(cnt.v_trap);
151
152	td = PCPU_GET(curthread);
153	p = td->td_proc;
154
155	type = ucode = frame->exc;
156	sig = 0;
157	user = frame->srr1 & PSL_PR;
158
159	CTR3(KTR_TRAP, "trap: %s type=%s (%s)", td->td_name,
160	    trapname(type), user ? "user" : "kernel");
161
162	if (user) {
163		td->td_pticks = 0;
164		td->td_frame = frame;
165		if (td->td_ucred != p->p_ucred)
166			cred_update_thread(td);
167
168		/* User Mode Traps */
169		switch (type) {
170		case EXC_RUNMODETRC:
171		case EXC_TRC:
172			frame->srr1 &= ~PSL_SE;
173			sig = SIGTRAP;
174			break;
175
176		case EXC_DSI:
177		case EXC_ISI:
178			sig = trap_pfault(frame, 1);
179			break;
180
181		case EXC_SC:
182			syscall(frame);
183			break;
184
185		case EXC_FPU:
186			KASSERT((td->td_pcb->pcb_flags & PCB_FPU) != PCB_FPU,
187			    ("FPU already enabled for thread"));
188			enable_fpu(td);
189			break;
190
191		case EXC_VEC:
192			KASSERT((td->td_pcb->pcb_flags & PCB_VEC) != PCB_VEC,
193			    ("Altivec already enabled for thread"));
194			enable_vec(td);
195			break;
196
197		case EXC_VECAST:
198			printf("Vector assist exception!\n");
199			sig = SIGILL;
200			break;
201
202		case EXC_ALI:
203			if (fix_unaligned(td, frame) != 0)
204				sig = SIGBUS;
205			else
206				frame->srr0 += 4;
207			break;
208
209		case EXC_PGM:
210			/* Identify the trap reason */
211			if (frame->srr1 & EXC_PGM_TRAP)
212				sig = SIGTRAP;
213 			else if (ppc_instr_emulate(frame) == 0)
214				frame->srr0 += 4;
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	if (sig != 0) {
243		if (p->p_sysent->sv_transtrap != NULL)
244			sig = (p->p_sysent->sv_transtrap)(sig, type);
245		ksiginfo_init_trap(&ksi);
246		ksi.ksi_signo = sig;
247		ksi.ksi_code = (int) ucode; /* XXX, not POSIX */
248		/* ksi.ksi_addr = ? */
249		ksi.ksi_trapno = type;
250		trapsignal(td, &ksi);
251	}
252
253	userret(td, frame);
254	mtx_assert(&Giant, MA_NOTOWNED);
255}
256
257static void
258trap_fatal(struct trapframe *frame)
259{
260
261	printtrap(frame->exc, frame, 1, (frame->srr1 & PSL_PR));
262#ifdef KDB
263	if ((debugger_on_panic || kdb_active) &&
264	    kdb_trap(frame->exc, 0, frame))
265		return;
266#endif
267	panic("%s trap", trapname(frame->exc));
268}
269
270static void
271printtrap(u_int vector, struct trapframe *frame, int isfatal, int user)
272{
273
274	printf("\n");
275	printf("%s %s trap:\n", isfatal ? "fatal" : "handled",
276	    user ? "user" : "kernel");
277	printf("\n");
278	printf("   exception       = 0x%x (%s)\n", vector >> 8,
279	    trapname(vector));
280	switch (vector) {
281	case EXC_DSI:
282		printf("   virtual address = 0x%x\n", frame->cpu.aim.dar);
283		break;
284	case EXC_ISI:
285		printf("   virtual address = 0x%x\n", frame->srr0);
286		break;
287	}
288	printf("   srr0            = 0x%x\n", frame->srr0);
289	printf("   srr1            = 0x%x\n", frame->srr1);
290	printf("   lr              = 0x%x\n", frame->lr);
291	printf("   curthread       = %p\n", curthread);
292	if (curthread != NULL)
293		printf("          pid = %d, comm = %s\n",
294		    curthread->td_proc->p_pid, curthread->td_name);
295	printf("\n");
296}
297
298/*
299 * Handles a fatal fault when we have onfault state to recover.  Returns
300 * non-zero if there was onfault recovery state available.
301 */
302static int
303handle_onfault(struct trapframe *frame)
304{
305	struct		thread *td;
306	faultbuf	*fb;
307
308	td = curthread;
309	fb = td->td_pcb->pcb_onfault;
310	if (fb != NULL) {
311		frame->srr0 = (*fb)[0];
312		frame->fixreg[1] = (*fb)[1];
313		frame->fixreg[2] = (*fb)[2];
314		frame->fixreg[3] = 1;
315		frame->cr = (*fb)[3];
316		bcopy(&(*fb)[4], &frame->fixreg[13],
317		    19 * sizeof(register_t));
318		return (1);
319	}
320	return (0);
321}
322
323void
324syscall(struct trapframe *frame)
325{
326	caddr_t		params;
327	struct		sysent *callp;
328	struct		thread *td;
329	struct		proc *p;
330	int		error, n;
331	size_t		narg;
332	register_t	args[10];
333	u_int		code;
334
335	td = PCPU_GET(curthread);
336	p = td->td_proc;
337
338	PCPU_INC(cnt.v_syscall);
339
340	code = frame->fixreg[0];
341	params = (caddr_t)(frame->fixreg + FIRSTARG);
342	n = NARGREG;
343
344	if (p->p_sysent->sv_prepsyscall) {
345		/*
346		 * The prep code is MP aware.
347		 */
348		(*p->p_sysent->sv_prepsyscall)(frame, args, &code, &params);
349	} else if (code == SYS_syscall) {
350		/*
351		 * code is first argument,
352		 * followed by actual args.
353		 */
354		code = *(u_int *) params;
355		params += sizeof(register_t);
356		n -= 1;
357	} else if (code == SYS___syscall) {
358		/*
359		 * Like syscall, but code is a quad,
360		 * so as to maintain quad alignment
361		 * for the rest of the args.
362		 */
363		params += sizeof(register_t);
364		code = *(u_int *) params;
365		params += sizeof(register_t);
366		n -= 2;
367	}
368
369 	if (p->p_sysent->sv_mask)
370 		code &= p->p_sysent->sv_mask;
371
372 	if (code >= p->p_sysent->sv_size)
373 		callp = &p->p_sysent->sv_table[0];
374  	else
375 		callp = &p->p_sysent->sv_table[code];
376
377	narg = callp->sy_narg;
378
379	if (narg > n) {
380		bcopy(params, args, n * sizeof(register_t));
381		error = copyin(MOREARGS(frame->fixreg[1]), args + n,
382			       (narg - n) * sizeof(register_t));
383		params = (caddr_t)args;
384	} else
385		error = 0;
386
387	CTR5(KTR_SYSC, "syscall: p=%s %s(%x %x %x)", td->td_name,
388	     syscallnames[code],
389	     frame->fixreg[FIRSTARG],
390	     frame->fixreg[FIRSTARG+1],
391	     frame->fixreg[FIRSTARG+2]);
392
393#ifdef	KTRACE
394	if (KTRPOINT(td, KTR_SYSCALL))
395		ktrsyscall(code, narg, (register_t *)params);
396#endif
397
398	td->td_syscalls++;
399
400	if (error == 0) {
401		td->td_retval[0] = 0;
402		td->td_retval[1] = frame->fixreg[FIRSTARG + 1];
403
404		STOPEVENT(p, S_SCE, narg);
405
406		PTRACESTOP_SC(p, td, S_PT_SCE);
407
408		AUDIT_SYSCALL_ENTER(code, td);
409		error = (*callp->sy_call)(td, params);
410		AUDIT_SYSCALL_EXIT(error, td);
411
412		CTR3(KTR_SYSC, "syscall: p=%s %s ret=%x", td->td_name,
413		     syscallnames[code], td->td_retval[0]);
414	}
415
416	cpu_set_syscall_retval(td, error);
417
418	/*
419	 * Check for misbehavior.
420	 */
421	WITNESS_WARN(WARN_PANIC, NULL, "System call %s returning",
422	    (code >= 0 && code < SYS_MAXSYSCALL) ? syscallnames[code] : "???");
423	KASSERT(td->td_critnest == 0,
424	    ("System call %s returning in a critical section",
425	    (code >= 0 && code < SYS_MAXSYSCALL) ? syscallnames[code] : "???"));
426	KASSERT(td->td_locks == 0,
427	    ("System call %s returning with %d locks held",
428	    (code >= 0 && code < SYS_MAXSYSCALL) ? syscallnames[code] : "???",
429	    td->td_locks));
430
431#ifdef	KTRACE
432	if (KTRPOINT(td, KTR_SYSRET))
433		ktrsysret(code, error, td->td_retval[0]);
434#endif
435
436	/*
437	 * Does the comment in the i386 code about errno apply here?
438	 */
439	STOPEVENT(p, S_SCX, code);
440
441	PTRACESTOP_SC(p, td, S_PT_SCX);
442}
443
444static int
445trap_pfault(struct trapframe *frame, int user)
446{
447	vm_offset_t	eva, va;
448	struct		thread *td;
449	struct		proc *p;
450	vm_map_t	map;
451	vm_prot_t	ftype;
452	int		rv;
453	u_int		user_sr;
454
455	td = curthread;
456	p = td->td_proc;
457	if (frame->exc == EXC_ISI) {
458		eva = frame->srr0;
459		ftype = VM_PROT_READ | VM_PROT_EXECUTE;
460	} else {
461		eva = frame->cpu.aim.dar;
462		if (frame->cpu.aim.dsisr & DSISR_STORE)
463			ftype = VM_PROT_WRITE;
464		else
465			ftype = VM_PROT_READ;
466	}
467
468	if (user) {
469		map = &p->p_vmspace->vm_map;
470	} else {
471		if ((eva >> ADDR_SR_SHFT) == USER_SR) {
472			if (p->p_vmspace == NULL)
473				return (SIGSEGV);
474
475			__asm ("mfsr %0, %1"
476			    : "=r"(user_sr)
477			    : "K"(USER_SR));
478			eva &= ADDR_PIDX | ADDR_POFF;
479			eva |= user_sr << ADDR_SR_SHFT;
480			map = &p->p_vmspace->vm_map;
481		} else {
482			map = kernel_map;
483		}
484	}
485	va = trunc_page(eva);
486
487	if (map != kernel_map) {
488		/*
489		 * Keep swapout from messing with us during this
490		 *	critical time.
491		 */
492		PROC_LOCK(p);
493		++p->p_lock;
494		PROC_UNLOCK(p);
495
496		/* Fault in the user page: */
497		rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL);
498
499		PROC_LOCK(p);
500		--p->p_lock;
501		PROC_UNLOCK(p);
502	} else {
503		/*
504		 * Don't have to worry about process locking or stacks in the
505		 * kernel.
506		 */
507		rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL);
508	}
509
510	if (rv == KERN_SUCCESS)
511		return (0);
512
513	if (!user && handle_onfault(frame))
514		return (0);
515
516	return (SIGSEGV);
517}
518
519int
520badaddr(void *addr, size_t size)
521{
522	return (badaddr_read(addr, size, NULL));
523}
524
525int
526badaddr_read(void *addr, size_t size, int *rptr)
527{
528	struct thread	*td;
529	faultbuf	env;
530	int		x;
531
532	/* Get rid of any stale machine checks that have been waiting.  */
533	__asm __volatile ("sync; isync");
534
535	td = PCPU_GET(curthread);
536
537	if (setfault(env)) {
538		td->td_pcb->pcb_onfault = 0;
539		__asm __volatile ("sync");
540		return 1;
541	}
542
543	__asm __volatile ("sync");
544
545	switch (size) {
546	case 1:
547		x = *(volatile int8_t *)addr;
548		break;
549	case 2:
550		x = *(volatile int16_t *)addr;
551		break;
552	case 4:
553		x = *(volatile int32_t *)addr;
554		break;
555	default:
556		panic("badaddr: invalid size (%d)", size);
557	}
558
559	/* Make sure we took the machine check, if we caused one. */
560	__asm __volatile ("sync; isync");
561
562	td->td_pcb->pcb_onfault = 0;
563	__asm __volatile ("sync");	/* To be sure. */
564
565	/* Use the value to avoid reorder. */
566	if (rptr)
567		*rptr = x;
568
569	return (0);
570}
571
572/*
573 * For now, this only deals with the particular unaligned access case
574 * that gcc tends to generate.  Eventually it should handle all of the
575 * possibilities that can happen on a 32-bit PowerPC in big-endian mode.
576 */
577
578static int
579fix_unaligned(struct thread *td, struct trapframe *frame)
580{
581	struct thread	*fputhread;
582	int		indicator, reg;
583	double		*fpr;
584
585	indicator = EXC_ALI_OPCODE_INDICATOR(frame->cpu.aim.dsisr);
586
587	switch (indicator) {
588	case EXC_ALI_LFD:
589	case EXC_ALI_STFD:
590		reg = EXC_ALI_RST(frame->cpu.aim.dsisr);
591		fpr = &td->td_pcb->pcb_fpu.fpr[reg];
592		fputhread = PCPU_GET(fputhread);
593
594		/* Juggle the FPU to ensure that we've initialized
595		 * the FPRs, and that their current state is in
596		 * the PCB.
597		 */
598		if (fputhread != td) {
599			if (fputhread)
600				save_fpu(fputhread);
601			enable_fpu(td);
602		}
603		save_fpu(td);
604
605		if (indicator == EXC_ALI_LFD) {
606			if (copyin((void *)frame->cpu.aim.dar, fpr,
607			    sizeof(double)) != 0)
608				return -1;
609			enable_fpu(td);
610		} else {
611			if (copyout(fpr, (void *)frame->cpu.aim.dar,
612			    sizeof(double)) != 0)
613				return -1;
614		}
615		return 0;
616		break;
617	}
618
619	return -1;
620}
621
622static int
623ppc_instr_emulate(struct trapframe *frame)
624{
625	uint32_t instr;
626	int reg;
627
628	instr = fuword32((void *)frame->srr0);
629
630	if ((instr & 0xfc1fffff) == 0x7c1f42a6) {	/* mfpvr */
631		reg = (instr & ~0xfc1fffff) >> 21;
632		frame->fixreg[reg] = mfpvr();
633		return (0);
634	}
635
636	return (-1);
637}
638
639