trap.c revision 266005 
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: stable/10/sys/powerpc/booke/trap.c 266005 2014-05-14 04:57:55Z ian $");
36
37#include "opt_fpu_emu.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#include <sys/vmmeter.h>
54
55#include <security/audit/audit.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/frame.h>
68#include <machine/pcb.h>
69#include <machine/pmap.h>
70#include <machine/psl.h>
71#include <machine/trap.h>
72#include <machine/spr.h>
73
74#define	FAULTBUF_LR	0
75#define	FAULTBUF_R1	1
76#define	FAULTBUF_R2	2
77#define	FAULTBUF_CR	3
78#define	FAULTBUF_CTR	4
79#define	FAULTBUF_XER	5
80#define	FAULTBUF_R13	6
81
82static void	trap_fatal(struct trapframe *frame);
83static void	printtrap(u_int vector, struct trapframe *frame, int isfatal,
84    int user);
85static int	trap_pfault(struct trapframe *frame, int user);
86static int	fix_unaligned(struct thread *td, struct trapframe *frame);
87static int	handle_onfault(struct trapframe *frame);
88static void	syscall(struct trapframe *frame);
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
96struct powerpc_exception {
97	u_int	vector;
98	char	*name;
99};
100
101static struct powerpc_exception powerpc_exceptions[] = {
102	{ EXC_CRIT,	"critical input" },
103	{ EXC_MCHK,	"machine check" },
104	{ EXC_DSI,	"data storage interrupt" },
105	{ EXC_ISI,	"instruction storage interrupt" },
106	{ EXC_EXI,	"external interrupt" },
107	{ EXC_ALI,	"alignment" },
108	{ EXC_PGM,	"program" },
109	{ EXC_SC,	"system call" },
110	{ EXC_APU,	"auxiliary proc unavailable" },
111	{ EXC_DECR,	"decrementer" },
112	{ EXC_FIT,	"fixed-interval timer" },
113	{ EXC_WDOG,	"watchdog timer" },
114	{ EXC_DTMISS,	"data tlb miss" },
115	{ EXC_ITMISS,	"instruction tlb miss" },
116	{ EXC_DEBUG,	"debug" },
117	{ EXC_PERF,	"performance monitoring" },
118	{ EXC_LAST,	NULL }
119};
120
121static const char *
122trapname(u_int vector)
123{
124	struct	powerpc_exception *pe;
125
126	for (pe = powerpc_exceptions; pe->vector != EXC_LAST; pe++) {
127		if (pe->vector == vector)
128			return (pe->name);
129	}
130
131	return ("unknown");
132}
133
134void
135trap(struct trapframe *frame)
136{
137	struct thread	*td;
138	struct proc	*p;
139	int		sig, type, user;
140	ksiginfo_t	ksi;
141
142#ifdef KDB
143	if (kdb_active) {
144		kdb_reenter();
145		return;
146	}
147#endif
148
149	PCPU_INC(cnt.v_trap);
150
151	td = curthread;
152	p = td->td_proc;
153
154	type = frame->exc;
155	sig = 0;
156	user = (frame->srr1 & PSL_PR) ? 1 : 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		td->td_frame = frame;
163		if (td->td_ucred != p->p_ucred)
164			cred_update_thread(td);
165
166		/* User Mode Traps */
167		switch (type) {
168		case EXC_DSI:
169		case EXC_ISI:
170			sig = trap_pfault(frame, 1);
171			break;
172
173		case EXC_SC:
174			syscall(frame);
175			break;
176
177		case EXC_ALI:
178			if (fix_unaligned(td, frame) != 0)
179				sig = SIGBUS;
180			else
181				frame->srr0 += 4;
182			break;
183
184		case EXC_DEBUG:	/* Single stepping */
185			mtspr(SPR_DBSR, mfspr(SPR_DBSR));
186			frame->srr1 &= ~PSL_DE;
187			frame->cpu.booke.dbcr0 &= ~(DBCR0_IDM || DBCR0_IC);
188			sig = SIGTRAP;
189			break;
190
191		case EXC_PGM:	/* Program exception */
192			sig = ppc_instr_emulate(frame, td->td_pcb);
193			break;
194
195		default:
196			trap_fatal(frame);
197		}
198	} else {
199		/* Kernel Mode Traps */
200		KASSERT(cold || td->td_ucred != NULL,
201		    ("kernel trap doesn't have ucred"));
202
203		switch (type) {
204		case EXC_DEBUG:
205			mtspr(SPR_DBSR, mfspr(SPR_DBSR));
206			kdb_trap(frame->exc, 0, frame);
207			return;
208
209		case EXC_DSI:
210			if (trap_pfault(frame, 0) == 0)
211 				return;
212			break;
213
214		case EXC_MCHK:
215			if (handle_onfault(frame))
216 				return;
217			break;
218#ifdef KDB
219		case EXC_PGM:
220			if (frame->cpu.booke.esr & ESR_PTR)
221				kdb_trap(EXC_PGM, 0, frame);
222			return;
223#endif
224		default:
225			break;
226		}
227		trap_fatal(frame);
228	}
229
230	if (sig != 0) {
231		if (p->p_sysent->sv_transtrap != NULL)
232			sig = (p->p_sysent->sv_transtrap)(sig, type);
233		ksiginfo_init_trap(&ksi);
234		ksi.ksi_signo = sig;
235		ksi.ksi_code = type; /* XXX, not POSIX */
236		/* ksi.ksi_addr = ? */
237		ksi.ksi_trapno = type;
238		trapsignal(td, &ksi);
239	}
240
241	userret(td, frame);
242}
243
244static void
245trap_fatal(struct trapframe *frame)
246{
247
248	printtrap(frame->exc, frame, 1, (frame->srr1 & PSL_PR));
249#ifdef KDB
250	if ((debugger_on_panic || kdb_active) &&
251	    kdb_trap(frame->exc, 0, frame))
252		return;
253#endif
254	panic("%s trap", trapname(frame->exc));
255}
256
257static void
258printtrap(u_int vector, struct trapframe *frame, int isfatal, int user)
259{
260	register_t va = 0;
261
262	printf("\n");
263	printf("%s %s trap:\n", isfatal ? "fatal" : "handled",
264	    user ? "user" : "kernel");
265	printf("\n");
266	printf("   exception       = 0x%x (%s)\n", vector, trapname(vector));
267
268	switch (vector) {
269	case EXC_DTMISS:
270	case EXC_DSI:
271		va = frame->cpu.booke.dear;
272		break;
273
274	case EXC_ITMISS:
275	case EXC_ISI:
276		va = frame->srr0;
277		break;
278	}
279
280	printf("   virtual address = 0x%08x\n", va);
281	printf("   srr0            = 0x%08x\n", frame->srr0);
282	printf("   srr1            = 0x%08x\n", frame->srr1);
283	printf("   curthread       = %p\n", curthread);
284	if (curthread != NULL)
285		printf("          pid = %d, comm = %s\n",
286		    curthread->td_proc->p_pid, curthread->td_proc->p_comm);
287	printf("\n");
288}
289
290/*
291 * Handles a fatal fault when we have onfault state to recover.  Returns
292 * non-zero if there was onfault recovery state available.
293 */
294static int
295handle_onfault(struct trapframe *frame)
296{
297	struct		thread *td;
298	faultbuf	*fb;
299
300	td = curthread;
301	fb = td->td_pcb->pcb_onfault;
302	if (fb != NULL) {
303		frame->srr0 = (*fb)[FAULTBUF_LR];
304		frame->fixreg[1] = (*fb)[FAULTBUF_R1];
305		frame->fixreg[2] = (*fb)[FAULTBUF_R2];
306		frame->fixreg[3] = 1;
307		frame->cr = (*fb)[FAULTBUF_CR];
308		frame->ctr = (*fb)[FAULTBUF_CTR];
309		frame->xer = (*fb)[FAULTBUF_XER];
310		bcopy(&(*fb)[FAULTBUF_R13], &frame->fixreg[13],
311		    19 * sizeof(register_t));
312		return (1);
313	}
314	return (0);
315}
316
317int
318cpu_fetch_syscall_args(struct thread *td, struct syscall_args *sa)
319{
320	struct proc *p;
321	struct trapframe *frame;
322	caddr_t	params;
323	int error, n;
324
325	p = td->td_proc;
326	frame = td->td_frame;
327
328	sa->code = frame->fixreg[0];
329	params = (caddr_t)(frame->fixreg + FIRSTARG);
330	n = NARGREG;
331
332	if (sa->code == SYS_syscall) {
333		/*
334		 * code is first argument,
335		 * followed by actual args.
336		 */
337		sa->code = *(u_int *) params;
338		params += sizeof(register_t);
339		n -= 1;
340	} else if (sa->code == SYS___syscall) {
341		/*
342		 * Like syscall, but code is a quad,
343		 * so as to maintain quad alignment
344		 * for the rest of the args.
345		 */
346		params += sizeof(register_t);
347		sa->code = *(u_int *) params;
348		params += sizeof(register_t);
349		n -= 2;
350	}
351
352	if (p->p_sysent->sv_mask)
353		sa->code &= p->p_sysent->sv_mask;
354	if (sa->code >= p->p_sysent->sv_size)
355		sa->callp = &p->p_sysent->sv_table[0];
356	else
357		sa->callp = &p->p_sysent->sv_table[sa->code];
358	sa->narg = sa->callp->sy_narg;
359
360	bcopy(params, sa->args, n * sizeof(register_t));
361	if (sa->narg > n) {
362		error = copyin(MOREARGS(frame->fixreg[1]), sa->args + n,
363		    (sa->narg - n) * sizeof(register_t));
364	} else
365		error = 0;
366
367	if (error == 0) {
368		td->td_retval[0] = 0;
369		td->td_retval[1] = frame->fixreg[FIRSTARG + 1];
370	}
371	return (error);
372}
373
374#include "../../kern/subr_syscall.c"
375
376void
377syscall(struct trapframe *frame)
378{
379	struct thread *td;
380	struct syscall_args sa;
381	int error;
382
383	td = curthread;
384	td->td_frame = frame;
385
386	error = syscallenter(td, &sa);
387	syscallret(td, error, &sa);
388}
389
390static int
391trap_pfault(struct trapframe *frame, int user)
392{
393	vm_offset_t	eva, va;
394	struct		thread *td;
395	struct		proc *p;
396	vm_map_t	map;
397	vm_prot_t	ftype;
398	int		rv;
399
400	td = curthread;
401	p = td->td_proc;
402
403	if (frame->exc == EXC_ISI) {
404		eva = frame->srr0;
405		ftype = VM_PROT_READ | VM_PROT_EXECUTE;
406
407	} else {
408		eva = frame->cpu.booke.dear;
409		if (frame->cpu.booke.esr & ESR_ST)
410			ftype = VM_PROT_WRITE;
411		else
412			ftype = VM_PROT_READ;
413	}
414
415	if (user) {
416		KASSERT(p->p_vmspace != NULL, ("trap_pfault: vmspace  NULL"));
417		map = &p->p_vmspace->vm_map;
418	} else {
419		if (eva < VM_MAXUSER_ADDRESS) {
420
421			if (p->p_vmspace == NULL)
422				return (SIGSEGV);
423
424			map = &p->p_vmspace->vm_map;
425
426		} else {
427			map = kernel_map;
428		}
429	}
430	va = trunc_page(eva);
431
432	if (map != kernel_map) {
433		/*
434		 * Keep swapout from messing with us during this
435		 *	critical time.
436		 */
437		PROC_LOCK(p);
438		++p->p_lock;
439		PROC_UNLOCK(p);
440
441		/* Fault in the user page: */
442		rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL);
443
444		PROC_LOCK(p);
445		--p->p_lock;
446		PROC_UNLOCK(p);
447	} else {
448		/*
449		 * Don't have to worry about process locking or stacks in the
450		 * kernel.
451		 */
452		rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL);
453	}
454
455	if (rv == KERN_SUCCESS)
456		return (0);
457
458	if (!user && handle_onfault(frame))
459		return (0);
460
461	return ((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV);
462}
463
464int
465badaddr(void *addr, size_t size)
466{
467
468	return (badaddr_read(addr, size, NULL));
469}
470
471int
472badaddr_read(void *addr, size_t size, int *rptr)
473{
474	struct thread	*td;
475	faultbuf	env;
476	int		x;
477
478	/* Get rid of any stale machine checks that have been waiting.  */
479	__asm __volatile ("sync; isync");
480
481	td = curthread;
482
483	if (setfault(env)) {
484		td->td_pcb->pcb_onfault = 0;
485		__asm __volatile ("sync");
486		return (1);
487	}
488
489	__asm __volatile ("sync");
490
491	switch (size) {
492	case 1:
493		x = *(volatile int8_t *)addr;
494		break;
495	case 2:
496		x = *(volatile int16_t *)addr;
497		break;
498	case 4:
499		x = *(volatile int32_t *)addr;
500		break;
501	default:
502		panic("badaddr: invalid size (%d)", size);
503	}
504
505	/* Make sure we took the machine check, if we caused one. */
506	__asm __volatile ("sync; isync");
507
508	td->td_pcb->pcb_onfault = 0;
509	__asm __volatile ("sync");	/* To be sure. */
510
511	/* Use the value to avoid reorder. */
512	if (rptr)
513		*rptr = x;
514
515	return (0);
516}
517
518/*
519 * For now, this only deals with the particular unaligned access case
520 * that gcc tends to generate.  Eventually it should handle all of the
521 * possibilities that can happen on a 32-bit PowerPC in big-endian mode.
522 */
523
524static int
525fix_unaligned(struct thread *td, struct trapframe *frame)
526{
527#if 0
528	struct thread	*fputhread;
529	int		indicator, reg;
530	double		*fpr;
531
532	indicator = EXC_ALI_OPCODE_INDICATOR(frame->dsisr);
533
534	switch (indicator) {
535	case EXC_ALI_LFD:
536	case EXC_ALI_STFD:
537		reg = EXC_ALI_RST(frame->dsisr);
538		fpr = &td->td_pcb->pcb_fpu.fpr[reg];
539		fputhread = PCPU_GET(fputhread);
540		/* Juggle the FPU to ensure that we've initialized
541		 * the FPRs, and that their current state is in
542		 * the PCB.
543		 */
544		if (fputhread != td) {
545			if (fputhread)
546				save_fpu(fputhread);
547			enable_fpu(td);
548		}
549		save_fpu(td);
550
551		if (indicator == EXC_ALI_LFD) {
552			if (copyin((void *)frame->dar, fpr,
553			    sizeof(double)) != 0)
554				return -1;
555			enable_fpu(td);
556		} else {
557			if (copyout(fpr, (void *)frame->dar,
558			    sizeof(double)) != 0)
559				return -1;
560		}
561		return 0;
562		break;
563	}
564
565#endif
566	return (-1);
567}
568
569#ifdef KDB
570int db_trap_glue(struct trapframe *);
571int
572db_trap_glue(struct trapframe *tf)
573{
574	if (!(tf->srr1 & PSL_PR))
575		return (kdb_trap(tf->exc, 0, tf));
576	return (0);
577}
578#endif
579