trap.c revision 266019 
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 266019 2014-05-14 14:08:45Z 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
90struct powerpc_exception {
91	u_int	vector;
92	char	*name;
93};
94
95static struct powerpc_exception powerpc_exceptions[] = {
96	{ EXC_CRIT,	"critical input" },
97	{ EXC_MCHK,	"machine check" },
98	{ EXC_DSI,	"data storage interrupt" },
99	{ EXC_ISI,	"instruction storage interrupt" },
100	{ EXC_EXI,	"external interrupt" },
101	{ EXC_ALI,	"alignment" },
102	{ EXC_PGM,	"program" },
103	{ EXC_SC,	"system call" },
104	{ EXC_APU,	"auxiliary proc unavailable" },
105	{ EXC_DECR,	"decrementer" },
106	{ EXC_FIT,	"fixed-interval timer" },
107	{ EXC_WDOG,	"watchdog timer" },
108	{ EXC_DTMISS,	"data tlb miss" },
109	{ EXC_ITMISS,	"instruction tlb miss" },
110	{ EXC_DEBUG,	"debug" },
111	{ EXC_PERF,	"performance monitoring" },
112	{ EXC_LAST,	NULL }
113};
114
115static const char *
116trapname(u_int vector)
117{
118	struct	powerpc_exception *pe;
119
120	for (pe = powerpc_exceptions; pe->vector != EXC_LAST; pe++) {
121		if (pe->vector == vector)
122			return (pe->name);
123	}
124
125	return ("unknown");
126}
127
128void
129trap(struct trapframe *frame)
130{
131	struct thread	*td;
132	struct proc	*p;
133	int		sig, type, user;
134	ksiginfo_t	ksi;
135
136#ifdef KDB
137	if (kdb_active) {
138		kdb_reenter();
139		return;
140	}
141#endif
142
143	PCPU_INC(cnt.v_trap);
144
145	td = curthread;
146	p = td->td_proc;
147
148	type = frame->exc;
149	sig = 0;
150	user = (frame->srr1 & PSL_PR) ? 1 : 0;
151
152	CTR3(KTR_TRAP, "trap: %s type=%s (%s)", p->p_comm,
153	    trapname(type), user ? "user" : "kernel");
154
155	if (user) {
156		td->td_frame = frame;
157		if (td->td_ucred != p->p_ucred)
158			cred_update_thread(td);
159
160		/* User Mode Traps */
161		switch (type) {
162		case EXC_DSI:
163		case EXC_ISI:
164			sig = trap_pfault(frame, 1);
165			break;
166
167		case EXC_SC:
168			syscall(frame);
169			break;
170
171		case EXC_ALI:
172			if (fix_unaligned(td, frame) != 0)
173				sig = SIGBUS;
174			else
175				frame->srr0 += 4;
176			break;
177
178		case EXC_DEBUG:	/* Single stepping */
179			mtspr(SPR_DBSR, mfspr(SPR_DBSR));
180			frame->srr1 &= ~PSL_DE;
181			frame->cpu.booke.dbcr0 &= ~(DBCR0_IDM || DBCR0_IC);
182			sig = SIGTRAP;
183			break;
184
185		case EXC_PGM:	/* Program exception */
186			sig = ppc_instr_emulate(frame, td->td_pcb);
187			break;
188
189		default:
190			trap_fatal(frame);
191		}
192	} else {
193		/* Kernel Mode Traps */
194		KASSERT(cold || td->td_ucred != NULL,
195		    ("kernel trap doesn't have ucred"));
196
197		switch (type) {
198		case EXC_DEBUG:
199			mtspr(SPR_DBSR, mfspr(SPR_DBSR));
200			kdb_trap(frame->exc, 0, frame);
201			return;
202
203		case EXC_DSI:
204			if (trap_pfault(frame, 0) == 0)
205 				return;
206			break;
207
208		case EXC_MCHK:
209			if (handle_onfault(frame))
210 				return;
211			break;
212#ifdef KDB
213		case EXC_PGM:
214			if (frame->cpu.booke.esr & ESR_PTR)
215				kdb_trap(EXC_PGM, 0, frame);
216			return;
217#endif
218		default:
219			break;
220		}
221		trap_fatal(frame);
222	}
223
224	if (sig != 0) {
225		if (p->p_sysent->sv_transtrap != NULL)
226			sig = (p->p_sysent->sv_transtrap)(sig, type);
227		ksiginfo_init_trap(&ksi);
228		ksi.ksi_signo = sig;
229		ksi.ksi_code = type; /* XXX, not POSIX */
230		/* ksi.ksi_addr = ? */
231		ksi.ksi_trapno = type;
232		trapsignal(td, &ksi);
233	}
234
235	userret(td, frame);
236}
237
238static void
239trap_fatal(struct trapframe *frame)
240{
241
242	printtrap(frame->exc, frame, 1, (frame->srr1 & PSL_PR));
243#ifdef KDB
244	if ((debugger_on_panic || kdb_active) &&
245	    kdb_trap(frame->exc, 0, frame))
246		return;
247#endif
248	panic("%s trap", trapname(frame->exc));
249}
250
251static void
252printtrap(u_int vector, struct trapframe *frame, int isfatal, int user)
253{
254	register_t va = 0;
255
256	printf("\n");
257	printf("%s %s trap:\n", isfatal ? "fatal" : "handled",
258	    user ? "user" : "kernel");
259	printf("\n");
260	printf("   exception       = 0x%x (%s)\n", vector, trapname(vector));
261
262	switch (vector) {
263	case EXC_DTMISS:
264	case EXC_DSI:
265		va = frame->cpu.booke.dear;
266		break;
267
268	case EXC_ITMISS:
269	case EXC_ISI:
270		va = frame->srr0;
271		break;
272	}
273
274	printf("   virtual address = 0x%08x\n", va);
275	printf("   srr0            = 0x%08x\n", frame->srr0);
276	printf("   srr1            = 0x%08x\n", frame->srr1);
277	printf("   curthread       = %p\n", curthread);
278	if (curthread != NULL)
279		printf("          pid = %d, comm = %s\n",
280		    curthread->td_proc->p_pid, curthread->td_proc->p_comm);
281	printf("\n");
282}
283
284/*
285 * Handles a fatal fault when we have onfault state to recover.  Returns
286 * non-zero if there was onfault recovery state available.
287 */
288static int
289handle_onfault(struct trapframe *frame)
290{
291	struct		thread *td;
292	faultbuf	*fb;
293
294	td = curthread;
295	fb = td->td_pcb->pcb_onfault;
296	if (fb != NULL) {
297		frame->srr0 = (*fb)[FAULTBUF_LR];
298		frame->fixreg[1] = (*fb)[FAULTBUF_R1];
299		frame->fixreg[2] = (*fb)[FAULTBUF_R2];
300		frame->fixreg[3] = 1;
301		frame->cr = (*fb)[FAULTBUF_CR];
302		frame->ctr = (*fb)[FAULTBUF_CTR];
303		frame->xer = (*fb)[FAULTBUF_XER];
304		bcopy(&(*fb)[FAULTBUF_R13], &frame->fixreg[13],
305		    19 * sizeof(register_t));
306		return (1);
307	}
308	return (0);
309}
310
311int
312cpu_fetch_syscall_args(struct thread *td, struct syscall_args *sa)
313{
314	struct proc *p;
315	struct trapframe *frame;
316	caddr_t	params;
317	int error, n;
318
319	p = td->td_proc;
320	frame = td->td_frame;
321
322	sa->code = frame->fixreg[0];
323	params = (caddr_t)(frame->fixreg + FIRSTARG);
324	n = NARGREG;
325
326	if (sa->code == SYS_syscall) {
327		/*
328		 * code is first argument,
329		 * followed by actual args.
330		 */
331		sa->code = *(u_int *) params;
332		params += sizeof(register_t);
333		n -= 1;
334	} else if (sa->code == SYS___syscall) {
335		/*
336		 * Like syscall, but code is a quad,
337		 * so as to maintain quad alignment
338		 * for the rest of the args.
339		 */
340		params += sizeof(register_t);
341		sa->code = *(u_int *) params;
342		params += sizeof(register_t);
343		n -= 2;
344	}
345
346	if (p->p_sysent->sv_mask)
347		sa->code &= p->p_sysent->sv_mask;
348	if (sa->code >= p->p_sysent->sv_size)
349		sa->callp = &p->p_sysent->sv_table[0];
350	else
351		sa->callp = &p->p_sysent->sv_table[sa->code];
352	sa->narg = sa->callp->sy_narg;
353
354	bcopy(params, sa->args, n * sizeof(register_t));
355	if (sa->narg > n) {
356		error = copyin(MOREARGS(frame->fixreg[1]), sa->args + n,
357		    (sa->narg - n) * sizeof(register_t));
358	} else
359		error = 0;
360
361	if (error == 0) {
362		td->td_retval[0] = 0;
363		td->td_retval[1] = frame->fixreg[FIRSTARG + 1];
364	}
365	return (error);
366}
367
368#include "../../kern/subr_syscall.c"
369
370void
371syscall(struct trapframe *frame)
372{
373	struct thread *td;
374	struct syscall_args sa;
375	int error;
376
377	td = curthread;
378	td->td_frame = frame;
379
380	error = syscallenter(td, &sa);
381	syscallret(td, error, &sa);
382}
383
384static int
385trap_pfault(struct trapframe *frame, int user)
386{
387	vm_offset_t	eva, va;
388	struct		thread *td;
389	struct		proc *p;
390	vm_map_t	map;
391	vm_prot_t	ftype;
392	int		rv;
393
394	td = curthread;
395	p = td->td_proc;
396
397	if (frame->exc == EXC_ISI) {
398		eva = frame->srr0;
399		ftype = VM_PROT_READ | VM_PROT_EXECUTE;
400
401	} else {
402		eva = frame->cpu.booke.dear;
403		if (frame->cpu.booke.esr & ESR_ST)
404			ftype = VM_PROT_WRITE;
405		else
406			ftype = VM_PROT_READ;
407	}
408
409	if (user) {
410		KASSERT(p->p_vmspace != NULL, ("trap_pfault: vmspace  NULL"));
411		map = &p->p_vmspace->vm_map;
412	} else {
413		if (eva < VM_MAXUSER_ADDRESS) {
414
415			if (p->p_vmspace == NULL)
416				return (SIGSEGV);
417
418			map = &p->p_vmspace->vm_map;
419
420		} else {
421			map = kernel_map;
422		}
423	}
424	va = trunc_page(eva);
425
426	if (map != kernel_map) {
427		/*
428		 * Keep swapout from messing with us during this
429		 *	critical time.
430		 */
431		PROC_LOCK(p);
432		++p->p_lock;
433		PROC_UNLOCK(p);
434
435		/* Fault in the user page: */
436		rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL);
437
438		PROC_LOCK(p);
439		--p->p_lock;
440		PROC_UNLOCK(p);
441	} else {
442		/*
443		 * Don't have to worry about process locking or stacks in the
444		 * kernel.
445		 */
446		rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL);
447	}
448
449	if (rv == KERN_SUCCESS)
450		return (0);
451
452	if (!user && handle_onfault(frame))
453		return (0);
454
455	return ((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV);
456}
457
458/*
459 * For now, this only deals with the particular unaligned access case
460 * that gcc tends to generate.  Eventually it should handle all of the
461 * possibilities that can happen on a 32-bit PowerPC in big-endian mode.
462 */
463
464static int
465fix_unaligned(struct thread *td, struct trapframe *frame)
466{
467#if 0
468	struct thread	*fputhread;
469	int		indicator, reg;
470	double		*fpr;
471
472	indicator = EXC_ALI_OPCODE_INDICATOR(frame->dsisr);
473
474	switch (indicator) {
475	case EXC_ALI_LFD:
476	case EXC_ALI_STFD:
477		reg = EXC_ALI_RST(frame->dsisr);
478		fpr = &td->td_pcb->pcb_fpu.fpr[reg];
479		fputhread = PCPU_GET(fputhread);
480		/* Juggle the FPU to ensure that we've initialized
481		 * the FPRs, and that their current state is in
482		 * the PCB.
483		 */
484		if (fputhread != td) {
485			if (fputhread)
486				save_fpu(fputhread);
487			enable_fpu(td);
488		}
489		save_fpu(td);
490
491		if (indicator == EXC_ALI_LFD) {
492			if (copyin((void *)frame->dar, fpr,
493			    sizeof(double)) != 0)
494				return -1;
495			enable_fpu(td);
496		} else {
497			if (copyout(fpr, (void *)frame->dar,
498			    sizeof(double)) != 0)
499				return -1;
500		}
501		return 0;
502		break;
503	}
504
505#endif
506	return (-1);
507}
508
509#ifdef KDB
510int db_trap_glue(struct trapframe *);
511int
512db_trap_glue(struct trapframe *tf)
513{
514	if (!(tf->srr1 & PSL_PR))
515		return (kdb_trap(tf->exc, 0, tf));
516	return (0);
517}
518#endif
519