trap.c revision 266004 
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 266004 2014-05-14 04:42:38Z 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#ifdef FPU_EMU
75#include <powerpc/fpu/fpu_extern.h>
76#endif
77
78#define	FAULTBUF_LR	0
79#define	FAULTBUF_R1	1
80#define	FAULTBUF_R2	2
81#define	FAULTBUF_CR	3
82#define	FAULTBUF_CTR	4
83#define	FAULTBUF_XER	5
84#define	FAULTBUF_R13	6
85
86static void	trap_fatal(struct trapframe *frame);
87static void	printtrap(u_int vector, struct trapframe *frame, int isfatal,
88    int user);
89static int	trap_pfault(struct trapframe *frame, int user);
90static int	fix_unaligned(struct thread *td, struct trapframe *frame);
91static int	handle_onfault(struct trapframe *frame);
92static void	syscall(struct trapframe *frame);
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
100struct powerpc_exception {
101	u_int	vector;
102	char	*name;
103};
104
105static struct powerpc_exception powerpc_exceptions[] = {
106	{ EXC_CRIT,	"critical input" },
107	{ EXC_MCHK,	"machine check" },
108	{ EXC_DSI,	"data storage interrupt" },
109	{ EXC_ISI,	"instruction storage interrupt" },
110	{ EXC_EXI,	"external interrupt" },
111	{ EXC_ALI,	"alignment" },
112	{ EXC_PGM,	"program" },
113	{ EXC_SC,	"system call" },
114	{ EXC_APU,	"auxiliary proc unavailable" },
115	{ EXC_DECR,	"decrementer" },
116	{ EXC_FIT,	"fixed-interval timer" },
117	{ EXC_WDOG,	"watchdog timer" },
118	{ EXC_DTMISS,	"data tlb miss" },
119	{ EXC_ITMISS,	"instruction tlb miss" },
120	{ EXC_DEBUG,	"debug" },
121	{ EXC_PERF,	"performance monitoring" },
122	{ EXC_LAST,	NULL }
123};
124
125static const char *
126trapname(u_int vector)
127{
128	struct	powerpc_exception *pe;
129
130	for (pe = powerpc_exceptions; pe->vector != EXC_LAST; pe++) {
131		if (pe->vector == vector)
132			return (pe->name);
133	}
134
135	return ("unknown");
136}
137
138void
139trap(struct trapframe *frame)
140{
141	struct thread	*td;
142	struct proc	*p;
143	int		sig, type, user;
144	ksiginfo_t	ksi;
145
146#ifdef KDB
147	if (kdb_active) {
148		kdb_reenter();
149		return;
150	}
151#endif
152
153	PCPU_INC(cnt.v_trap);
154
155	td = curthread;
156	p = td->td_proc;
157
158	type = frame->exc;
159	sig = 0;
160	user = (frame->srr1 & PSL_PR) ? 1 : 0;
161
162	CTR3(KTR_TRAP, "trap: %s type=%s (%s)", p->p_comm,
163	    trapname(type), user ? "user" : "kernel");
164
165	if (user) {
166		td->td_frame = frame;
167		if (td->td_ucred != p->p_ucred)
168			cred_update_thread(td);
169
170		/* User Mode Traps */
171		switch (type) {
172		case EXC_DSI:
173		case EXC_ISI:
174			sig = trap_pfault(frame, 1);
175			break;
176
177		case EXC_SC:
178			syscall(frame);
179			break;
180
181		case EXC_ALI:
182			if (fix_unaligned(td, frame) != 0)
183				sig = SIGBUS;
184			else
185				frame->srr0 += 4;
186			break;
187
188		case EXC_DEBUG:	/* Single stepping */
189			mtspr(SPR_DBSR, mfspr(SPR_DBSR));
190			frame->srr1 &= ~PSL_DE;
191			frame->cpu.booke.dbcr0 &= ~(DBCR0_IDM || DBCR0_IC);
192			sig = SIGTRAP;
193			break;
194
195		case EXC_PGM:	/* Program exception */
196#ifdef FPU_EMU
197			if (!(td->td_pcb->pcb_flags & PCB_FPREGS)) {
198				bzero(&td->td_pcb->pcb_fpu,
199				    sizeof(td->td_pcb->pcb_fpu));
200				td->td_pcb->pcb_flags |= PCB_FPREGS;
201			}
202			sig = fpu_emulate(frame,
203			    (struct fpreg *)&td->td_pcb->pcb_fpu);
204#else
205			/* XXX SIGILL for non-trap instructions. */
206			sig = SIGTRAP;
207#endif
208			break;
209
210		default:
211			trap_fatal(frame);
212		}
213	} else {
214		/* Kernel Mode Traps */
215		KASSERT(cold || td->td_ucred != NULL,
216		    ("kernel trap doesn't have ucred"));
217
218		switch (type) {
219		case EXC_DEBUG:
220			mtspr(SPR_DBSR, mfspr(SPR_DBSR));
221			kdb_trap(frame->exc, 0, frame);
222			return;
223
224		case EXC_DSI:
225			if (trap_pfault(frame, 0) == 0)
226 				return;
227			break;
228
229		case EXC_MCHK:
230			if (handle_onfault(frame))
231 				return;
232			break;
233#ifdef KDB
234		case EXC_PGM:
235			if (frame->cpu.booke.esr & ESR_PTR)
236				kdb_trap(EXC_PGM, 0, frame);
237			return;
238#endif
239		default:
240			break;
241		}
242		trap_fatal(frame);
243	}
244
245	if (sig != 0) {
246		if (p->p_sysent->sv_transtrap != NULL)
247			sig = (p->p_sysent->sv_transtrap)(sig, type);
248		ksiginfo_init_trap(&ksi);
249		ksi.ksi_signo = sig;
250		ksi.ksi_code = type; /* XXX, not POSIX */
251		/* ksi.ksi_addr = ? */
252		ksi.ksi_trapno = type;
253		trapsignal(td, &ksi);
254	}
255
256	userret(td, frame);
257}
258
259static void
260trap_fatal(struct trapframe *frame)
261{
262
263	printtrap(frame->exc, frame, 1, (frame->srr1 & PSL_PR));
264#ifdef KDB
265	if ((debugger_on_panic || kdb_active) &&
266	    kdb_trap(frame->exc, 0, frame))
267		return;
268#endif
269	panic("%s trap", trapname(frame->exc));
270}
271
272static void
273printtrap(u_int vector, struct trapframe *frame, int isfatal, int user)
274{
275	register_t va = 0;
276
277	printf("\n");
278	printf("%s %s trap:\n", isfatal ? "fatal" : "handled",
279	    user ? "user" : "kernel");
280	printf("\n");
281	printf("   exception       = 0x%x (%s)\n", vector, trapname(vector));
282
283	switch (vector) {
284	case EXC_DTMISS:
285	case EXC_DSI:
286		va = frame->cpu.booke.dear;
287		break;
288
289	case EXC_ITMISS:
290	case EXC_ISI:
291		va = frame->srr0;
292		break;
293	}
294
295	printf("   virtual address = 0x%08x\n", va);
296	printf("   srr0            = 0x%08x\n", frame->srr0);
297	printf("   srr1            = 0x%08x\n", frame->srr1);
298	printf("   curthread       = %p\n", curthread);
299	if (curthread != NULL)
300		printf("          pid = %d, comm = %s\n",
301		    curthread->td_proc->p_pid, curthread->td_proc->p_comm);
302	printf("\n");
303}
304
305/*
306 * Handles a fatal fault when we have onfault state to recover.  Returns
307 * non-zero if there was onfault recovery state available.
308 */
309static int
310handle_onfault(struct trapframe *frame)
311{
312	struct		thread *td;
313	faultbuf	*fb;
314
315	td = curthread;
316	fb = td->td_pcb->pcb_onfault;
317	if (fb != NULL) {
318		frame->srr0 = (*fb)[FAULTBUF_LR];
319		frame->fixreg[1] = (*fb)[FAULTBUF_R1];
320		frame->fixreg[2] = (*fb)[FAULTBUF_R2];
321		frame->fixreg[3] = 1;
322		frame->cr = (*fb)[FAULTBUF_CR];
323		frame->ctr = (*fb)[FAULTBUF_CTR];
324		frame->xer = (*fb)[FAULTBUF_XER];
325		bcopy(&(*fb)[FAULTBUF_R13], &frame->fixreg[13],
326		    19 * sizeof(register_t));
327		return (1);
328	}
329	return (0);
330}
331
332int
333cpu_fetch_syscall_args(struct thread *td, struct syscall_args *sa)
334{
335	struct proc *p;
336	struct trapframe *frame;
337	caddr_t	params;
338	int error, n;
339
340	p = td->td_proc;
341	frame = td->td_frame;
342
343	sa->code = frame->fixreg[0];
344	params = (caddr_t)(frame->fixreg + FIRSTARG);
345	n = NARGREG;
346
347	if (sa->code == SYS_syscall) {
348		/*
349		 * code is first argument,
350		 * followed by actual args.
351		 */
352		sa->code = *(u_int *) params;
353		params += sizeof(register_t);
354		n -= 1;
355	} else if (sa->code == SYS___syscall) {
356		/*
357		 * Like syscall, but code is a quad,
358		 * so as to maintain quad alignment
359		 * for the rest of the args.
360		 */
361		params += sizeof(register_t);
362		sa->code = *(u_int *) params;
363		params += sizeof(register_t);
364		n -= 2;
365	}
366
367	if (p->p_sysent->sv_mask)
368		sa->code &= p->p_sysent->sv_mask;
369	if (sa->code >= p->p_sysent->sv_size)
370		sa->callp = &p->p_sysent->sv_table[0];
371	else
372		sa->callp = &p->p_sysent->sv_table[sa->code];
373	sa->narg = sa->callp->sy_narg;
374
375	bcopy(params, sa->args, n * sizeof(register_t));
376	if (sa->narg > n) {
377		error = copyin(MOREARGS(frame->fixreg[1]), sa->args + n,
378		    (sa->narg - n) * sizeof(register_t));
379	} else
380		error = 0;
381
382	if (error == 0) {
383		td->td_retval[0] = 0;
384		td->td_retval[1] = frame->fixreg[FIRSTARG + 1];
385	}
386	return (error);
387}
388
389#include "../../kern/subr_syscall.c"
390
391void
392syscall(struct trapframe *frame)
393{
394	struct thread *td;
395	struct syscall_args sa;
396	int error;
397
398	td = curthread;
399	td->td_frame = frame;
400
401	error = syscallenter(td, &sa);
402	syscallret(td, error, &sa);
403}
404
405static int
406trap_pfault(struct trapframe *frame, int user)
407{
408	vm_offset_t	eva, va;
409	struct		thread *td;
410	struct		proc *p;
411	vm_map_t	map;
412	vm_prot_t	ftype;
413	int		rv;
414
415	td = curthread;
416	p = td->td_proc;
417
418	if (frame->exc == EXC_ISI) {
419		eva = frame->srr0;
420		ftype = VM_PROT_READ | VM_PROT_EXECUTE;
421
422	} else {
423		eva = frame->cpu.booke.dear;
424		if (frame->cpu.booke.esr & ESR_ST)
425			ftype = VM_PROT_WRITE;
426		else
427			ftype = VM_PROT_READ;
428	}
429
430	if (user) {
431		KASSERT(p->p_vmspace != NULL, ("trap_pfault: vmspace  NULL"));
432		map = &p->p_vmspace->vm_map;
433	} else {
434		if (eva < VM_MAXUSER_ADDRESS) {
435
436			if (p->p_vmspace == NULL)
437				return (SIGSEGV);
438
439			map = &p->p_vmspace->vm_map;
440
441		} else {
442			map = kernel_map;
443		}
444	}
445	va = trunc_page(eva);
446
447	if (map != kernel_map) {
448		/*
449		 * Keep swapout from messing with us during this
450		 *	critical time.
451		 */
452		PROC_LOCK(p);
453		++p->p_lock;
454		PROC_UNLOCK(p);
455
456		/* Fault in the user page: */
457		rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL);
458
459		PROC_LOCK(p);
460		--p->p_lock;
461		PROC_UNLOCK(p);
462	} else {
463		/*
464		 * Don't have to worry about process locking or stacks in the
465		 * kernel.
466		 */
467		rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL);
468	}
469
470	if (rv == KERN_SUCCESS)
471		return (0);
472
473	if (!user && handle_onfault(frame))
474		return (0);
475
476	return ((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV);
477}
478
479int
480badaddr(void *addr, size_t size)
481{
482
483	return (badaddr_read(addr, size, NULL));
484}
485
486int
487badaddr_read(void *addr, size_t size, int *rptr)
488{
489	struct thread	*td;
490	faultbuf	env;
491	int		x;
492
493	/* Get rid of any stale machine checks that have been waiting.  */
494	__asm __volatile ("sync; isync");
495
496	td = curthread;
497
498	if (setfault(env)) {
499		td->td_pcb->pcb_onfault = 0;
500		__asm __volatile ("sync");
501		return (1);
502	}
503
504	__asm __volatile ("sync");
505
506	switch (size) {
507	case 1:
508		x = *(volatile int8_t *)addr;
509		break;
510	case 2:
511		x = *(volatile int16_t *)addr;
512		break;
513	case 4:
514		x = *(volatile int32_t *)addr;
515		break;
516	default:
517		panic("badaddr: invalid size (%d)", size);
518	}
519
520	/* Make sure we took the machine check, if we caused one. */
521	__asm __volatile ("sync; isync");
522
523	td->td_pcb->pcb_onfault = 0;
524	__asm __volatile ("sync");	/* To be sure. */
525
526	/* Use the value to avoid reorder. */
527	if (rptr)
528		*rptr = x;
529
530	return (0);
531}
532
533/*
534 * For now, this only deals with the particular unaligned access case
535 * that gcc tends to generate.  Eventually it should handle all of the
536 * possibilities that can happen on a 32-bit PowerPC in big-endian mode.
537 */
538
539static int
540fix_unaligned(struct thread *td, struct trapframe *frame)
541{
542#if 0
543	struct thread	*fputhread;
544	int		indicator, reg;
545	double		*fpr;
546
547	indicator = EXC_ALI_OPCODE_INDICATOR(frame->dsisr);
548
549	switch (indicator) {
550	case EXC_ALI_LFD:
551	case EXC_ALI_STFD:
552		reg = EXC_ALI_RST(frame->dsisr);
553		fpr = &td->td_pcb->pcb_fpu.fpr[reg];
554		fputhread = PCPU_GET(fputhread);
555		/* Juggle the FPU to ensure that we've initialized
556		 * the FPRs, and that their current state is in
557		 * the PCB.
558		 */
559		if (fputhread != td) {
560			if (fputhread)
561				save_fpu(fputhread);
562			enable_fpu(td);
563		}
564		save_fpu(td);
565
566		if (indicator == EXC_ALI_LFD) {
567			if (copyin((void *)frame->dar, fpr,
568			    sizeof(double)) != 0)
569				return -1;
570			enable_fpu(td);
571		} else {
572			if (copyout(fpr, (void *)frame->dar,
573			    sizeof(double)) != 0)
574				return -1;
575		}
576		return 0;
577		break;
578	}
579
580#endif
581	return (-1);
582}
583
584#ifdef KDB
585int db_trap_glue(struct trapframe *);
586int
587db_trap_glue(struct trapframe *tf)
588{
589	if (!(tf->srr1 & PSL_PR))
590		return (kdb_trap(tf->exc, 0, tf));
591	return (0);
592}
593#endif
594