1 /*-
2 * Mach Operating System
3 * Copyright (c) 1991,1990 Carnegie Mellon University
4 * All Rights Reserved.
5 *
6 * Permission to use, copy, modify and distribute this software and its
7 * documentation is hereby granted, provided that both the copyright
8 * notice and this permission notice appear in all copies of the
9 * software, derivative works or modified versions, and any portions
10 * thereof, and that both notices appear in supporting documentation.
11 *
12 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS
13 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
14 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
15 *
16 * Carnegie Mellon requests users of this software to return to
17 *
18 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
19 * School of Computer Science
20 * Carnegie Mellon University
21 * Pittsburgh PA 15213-3890
22 *
23 * any improvements or extensions that they make and grant Carnegie the
24 * rights to redistribute these changes.
25 */
26
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD: releng/9.2/sys/i386/i386/db_trace.c 244337 2012-12-17 05:13:15Z kib $");
29
30 #include <sys/param.h>
31 #include <sys/systm.h>
32 #include <sys/kdb.h>
33 #include <sys/proc.h>
34 #include <sys/sysent.h>
35
36 #include <machine/cpu.h>
37 #include <machine/md_var.h>
38 #include <machine/pcb.h>
39 #include <machine/reg.h>
40 #include <machine/stack.h>
41
42 #include <vm/vm.h>
43 #include <vm/vm_param.h>
44 #include <vm/pmap.h>
45
46 #include <ddb/ddb.h>
47 #include <ddb/db_access.h>
48 #include <ddb/db_sym.h>
49 #include <ddb/db_variables.h>
50
51 static db_varfcn_t db_dr0;
52 static db_varfcn_t db_dr1;
53 static db_varfcn_t db_dr2;
54 static db_varfcn_t db_dr3;
55 static db_varfcn_t db_dr4;
56 static db_varfcn_t db_dr5;
57 static db_varfcn_t db_dr6;
58 static db_varfcn_t db_dr7;
59 static db_varfcn_t db_esp;
60 static db_varfcn_t db_frame;
61 static db_varfcn_t db_ss;
62
63 /*
64 * Machine register set.
65 */
66 #define DB_OFFSET(x) (db_expr_t *)offsetof(struct trapframe, x)
67 struct db_variable db_regs[] = {
68 { "cs", DB_OFFSET(tf_cs), db_frame },
69 { "ds", DB_OFFSET(tf_ds), db_frame },
70 { "es", DB_OFFSET(tf_es), db_frame },
71 { "fs", DB_OFFSET(tf_fs), db_frame },
72 { "ss", NULL, db_ss },
73 { "eax", DB_OFFSET(tf_eax), db_frame },
74 { "ecx", DB_OFFSET(tf_ecx), db_frame },
75 { "edx", DB_OFFSET(tf_edx), db_frame },
76 { "ebx", DB_OFFSET(tf_ebx), db_frame },
77 { "esp", NULL, db_esp },
78 { "ebp", DB_OFFSET(tf_ebp), db_frame },
79 { "esi", DB_OFFSET(tf_esi), db_frame },
80 { "edi", DB_OFFSET(tf_edi), db_frame },
81 { "eip", DB_OFFSET(tf_eip), db_frame },
82 { "efl", DB_OFFSET(tf_eflags), db_frame },
83 #define DB_N_SHOW_REGS 15 /* Don't show registers after here. */
84 { "dr0", NULL, db_dr0 },
85 { "dr1", NULL, db_dr1 },
86 { "dr2", NULL, db_dr2 },
87 { "dr3", NULL, db_dr3 },
88 { "dr4", NULL, db_dr4 },
89 { "dr5", NULL, db_dr5 },
90 { "dr6", NULL, db_dr6 },
91 { "dr7", NULL, db_dr7 },
92 };
93 struct db_variable *db_eregs = db_regs + DB_N_SHOW_REGS;
94
95 #define DB_DRX_FUNC(reg) \
96 static int \
97 db_ ## reg (vp, valuep, op) \
98 struct db_variable *vp; \
99 db_expr_t * valuep; \
100 int op; \
101 { \
102 if (op == DB_VAR_GET) \
103 *valuep = r ## reg (); \
104 else \
105 load_ ## reg (*valuep); \
106 return (1); \
107 }
108
109 DB_DRX_FUNC(dr0)
110 DB_DRX_FUNC(dr1)
111 DB_DRX_FUNC(dr2)
112 DB_DRX_FUNC(dr3)
113 DB_DRX_FUNC(dr4)
114 DB_DRX_FUNC(dr5)
115 DB_DRX_FUNC(dr6)
116 DB_DRX_FUNC(dr7)
117
118 static __inline int
119 get_esp(struct trapframe *tf)
120 {
121 return ((ISPL(tf->tf_cs)) ? tf->tf_esp :
122 (db_expr_t)tf + (uintptr_t)DB_OFFSET(tf_esp));
123 }
124
125 static int
126 db_frame(struct db_variable *vp, db_expr_t *valuep, int op)
127 {
128 int *reg;
129
130 if (kdb_frame == NULL)
131 return (0);
132
133 reg = (int *)((uintptr_t)kdb_frame + (db_expr_t)vp->valuep);
134 if (op == DB_VAR_GET)
135 *valuep = *reg;
136 else
137 *reg = *valuep;
138 return (1);
139 }
140
141 static int
142 db_esp(struct db_variable *vp, db_expr_t *valuep, int op)
143 {
144
145 if (kdb_frame == NULL)
146 return (0);
147
148 if (op == DB_VAR_GET)
149 *valuep = get_esp(kdb_frame);
150 else if (ISPL(kdb_frame->tf_cs))
151 kdb_frame->tf_esp = *valuep;
152 return (1);
153 }
154
155 static int
156 db_ss(struct db_variable *vp, db_expr_t *valuep, int op)
157 {
158
159 if (kdb_frame == NULL)
160 return (0);
161
162 if (op == DB_VAR_GET)
163 *valuep = (ISPL(kdb_frame->tf_cs)) ? kdb_frame->tf_ss : rss();
164 else if (ISPL(kdb_frame->tf_cs))
165 kdb_frame->tf_ss = *valuep;
166 return (1);
167 }
168
169 #define NORMAL 0
170 #define TRAP 1
171 #define INTERRUPT 2
172 #define SYSCALL 3
173 #define DOUBLE_FAULT 4
174 #define TRAP_INTERRUPT 5
175 #define TRAP_TIMERINT 6
176
177 static void db_nextframe(struct i386_frame **, db_addr_t *, struct thread *);
178 static int db_numargs(struct i386_frame *);
179 static void db_print_stack_entry(const char *, int, char **, int *, db_addr_t,
180 void *);
181 static void decode_syscall(int, struct thread *);
182
183 static const char * watchtype_str(int type);
184 int i386_set_watch(int watchnum, unsigned int watchaddr, int size, int access,
185 struct dbreg *d);
186 int i386_clr_watch(int watchnum, struct dbreg *d);
187
188 /*
189 * Figure out how many arguments were passed into the frame at "fp".
190 */
191 static int
192 db_numargs(fp)
193 struct i386_frame *fp;
194 {
195 char *argp;
196 int inst;
197 int args;
198
199 argp = (char *)db_get_value((int)&fp->f_retaddr, 4, FALSE);
200 /*
201 * XXX etext is wrong for LKMs. We should attempt to interpret
202 * the instruction at the return address in all cases. This
203 * may require better fault handling.
204 */
205 if (argp < btext || argp >= etext) {
206 args = -1;
207 } else {
208 retry:
209 inst = db_get_value((int)argp, 4, FALSE);
210 if ((inst & 0xff) == 0x59) /* popl %ecx */
211 args = 1;
212 else if ((inst & 0xffff) == 0xc483) /* addl $Ibs, %esp */
213 args = ((inst >> 16) & 0xff) / 4;
214 else if ((inst & 0xf8ff) == 0xc089) { /* movl %eax, %Reg */
215 argp += 2;
216 goto retry;
217 } else
218 args = -1;
219 }
220 return (args);
221 }
222
223 static void
224 db_print_stack_entry(name, narg, argnp, argp, callpc, frame)
225 const char *name;
226 int narg;
227 char **argnp;
228 int *argp;
229 db_addr_t callpc;
230 void *frame;
231 {
232 int n = narg >= 0 ? narg : 5;
233
234 db_printf("%s(", name);
235 while (n) {
236 if (argnp)
237 db_printf("%s=", *argnp++);
238 db_printf("%r", db_get_value((int)argp, 4, FALSE));
239 argp++;
240 if (--n != 0)
241 db_printf(",");
242 }
243 if (narg < 0)
244 db_printf(",...");
245 db_printf(") at ");
246 db_printsym(callpc, DB_STGY_PROC);
247 if (frame != NULL)
248 db_printf("/frame 0x%r", (register_t)frame);
249 db_printf("\n");
250 }
251
252 static void
253 decode_syscall(int number, struct thread *td)
254 {
255 struct proc *p;
256 c_db_sym_t sym;
257 db_expr_t diff;
258 sy_call_t *f;
259 const char *symname;
260
261 db_printf(" (%d", number);
262 p = (td != NULL) ? td->td_proc : NULL;
263 if (p != NULL && 0 <= number && number < p->p_sysent->sv_size) {
264 f = p->p_sysent->sv_table[number].sy_call;
265 sym = db_search_symbol((db_addr_t)f, DB_STGY_ANY, &diff);
266 if (sym != DB_SYM_NULL && diff == 0) {
267 db_symbol_values(sym, &symname, NULL);
268 db_printf(", %s, %s", p->p_sysent->sv_name, symname);
269 }
270 }
271 db_printf(")");
272 }
273
274 /*
275 * Figure out the next frame up in the call stack.
276 */
277 static void
278 db_nextframe(struct i386_frame **fp, db_addr_t *ip, struct thread *td)
279 {
280 struct trapframe *tf;
281 int frame_type;
282 int eip, esp, ebp;
283 db_expr_t offset;
284 c_db_sym_t sym;
285 const char *name;
286
287 eip = db_get_value((int) &(*fp)->f_retaddr, 4, FALSE);
288 ebp = db_get_value((int) &(*fp)->f_frame, 4, FALSE);
289
290 /*
291 * Figure out frame type. We look at the address just before
292 * the saved instruction pointer as the saved EIP is after the
293 * call function, and if the function being called is marked as
294 * dead (such as panic() at the end of dblfault_handler()), then
295 * the instruction at the saved EIP will be part of a different
296 * function (syscall() in this example) rather than the one that
297 * actually made the call.
298 */
299 frame_type = NORMAL;
300 sym = db_search_symbol(eip - 1, DB_STGY_ANY, &offset);
301 db_symbol_values(sym, &name, NULL);
302 if (name != NULL) {
303 if (strcmp(name, "calltrap") == 0 ||
304 strcmp(name, "fork_trampoline") == 0)
305 frame_type = TRAP;
306 else if (strncmp(name, "Xatpic_intr", 11) == 0 ||
307 strncmp(name, "Xapic_isr", 9) == 0)
308 frame_type = INTERRUPT;
309 else if (strcmp(name, "Xlcall_syscall") == 0 ||
310 strcmp(name, "Xint0x80_syscall") == 0)
311 frame_type = SYSCALL;
312 else if (strcmp(name, "dblfault_handler") == 0)
313 frame_type = DOUBLE_FAULT;
314 /* XXX: These are interrupts with trap frames. */
315 else if (strcmp(name, "Xtimerint") == 0)
316 frame_type = TRAP_TIMERINT;
317 else if (strcmp(name, "Xcpustop") == 0 ||
318 strcmp(name, "Xrendezvous") == 0 ||
319 strcmp(name, "Xipi_intr_bitmap_handler") == 0 ||
320 strcmp(name, "Xlazypmap") == 0)
321 frame_type = TRAP_INTERRUPT;
322 }
323
324 /*
325 * Normal frames need no special processing.
326 */
327 if (frame_type == NORMAL) {
328 *ip = (db_addr_t) eip;
329 *fp = (struct i386_frame *) ebp;
330 return;
331 }
332
333 db_print_stack_entry(name, 0, 0, 0, eip, &(*fp)->f_frame);
334
335 /*
336 * For a double fault, we have to snag the values from the
337 * previous TSS since a double fault uses a task gate to
338 * switch to a known good state.
339 */
340 if (frame_type == DOUBLE_FAULT) {
341 esp = PCPU_GET(common_tss.tss_esp);
342 eip = PCPU_GET(common_tss.tss_eip);
343 ebp = PCPU_GET(common_tss.tss_ebp);
344 db_printf(
345 "--- trap 0x17, eip = %#r, esp = %#r, ebp = %#r ---\n",
346 eip, esp, ebp);
347 *ip = (db_addr_t) eip;
348 *fp = (struct i386_frame *) ebp;
349 return;
350 }
351
352 /*
353 * Point to base of trapframe which is just above the
354 * current frame.
355 */
356 if (frame_type == INTERRUPT)
357 tf = (struct trapframe *)((int)*fp + 16);
358 else if (frame_type == TRAP_INTERRUPT)
359 tf = (struct trapframe *)((int)*fp + 8);
360 else
361 tf = (struct trapframe *)((int)*fp + 12);
362
363 if (INKERNEL((int) tf)) {
364 esp = get_esp(tf);
365 eip = tf->tf_eip;
366 ebp = tf->tf_ebp;
367 switch (frame_type) {
368 case TRAP:
369 db_printf("--- trap %#r", tf->tf_trapno);
370 break;
371 case SYSCALL:
372 db_printf("--- syscall");
373 decode_syscall(tf->tf_eax, td);
374 break;
375 case TRAP_TIMERINT:
376 case TRAP_INTERRUPT:
377 case INTERRUPT:
378 db_printf("--- interrupt");
379 break;
380 default:
381 panic("The moon has moved again.");
382 }
383 db_printf(", eip = %#r, esp = %#r, ebp = %#r ---\n", eip,
384 esp, ebp);
385 }
386
387 *ip = (db_addr_t) eip;
388 *fp = (struct i386_frame *) ebp;
389 }
390
391 static int
392 db_backtrace(struct thread *td, struct trapframe *tf, struct i386_frame *frame,
393 db_addr_t pc, int count)
394 {
395 struct i386_frame *actframe;
396 #define MAXNARG 16
397 char *argnames[MAXNARG], **argnp = NULL;
398 const char *name;
399 int *argp;
400 db_expr_t offset;
401 c_db_sym_t sym;
402 int instr, narg;
403 boolean_t first;
404
405 /*
406 * If an indirect call via an invalid pointer caused a trap,
407 * %pc contains the invalid address while the return address
408 * of the unlucky caller has been saved by CPU on the stack
409 * just before the trap frame. In this case, try to recover
410 * the caller's address so that the first frame is assigned
411 * to the right spot in the right function, for that is where
412 * the failure actually happened.
413 *
414 * This trick depends on the fault address stashed in tf_err
415 * by trap_fatal() before entering KDB.
416 */
417 if (kdb_frame && pc == kdb_frame->tf_err) {
418 /*
419 * Find where the trap frame actually ends.
420 * It won't contain tf_esp or tf_ss unless crossing rings.
421 */
422 if (ISPL(kdb_frame->tf_cs))
423 instr = (int)(kdb_frame + 1);
424 else
425 instr = (int)&kdb_frame->tf_esp;
426 pc = db_get_value(instr, 4, FALSE);
427 }
428
429 if (count == -1)
430 count = 1024;
431
432 first = TRUE;
433 while (count-- && !db_pager_quit) {
434 sym = db_search_symbol(pc, DB_STGY_ANY, &offset);
435 db_symbol_values(sym, &name, NULL);
436
437 /*
438 * Attempt to determine a (possibly fake) frame that gives
439 * the caller's pc. It may differ from `frame' if the
440 * current function never sets up a standard frame or hasn't
441 * set one up yet or has just discarded one. The last two
442 * cases can be guessed fairly reliably for code generated
443 * by gcc. The first case is too much trouble to handle in
444 * general because the amount of junk on the stack depends
445 * on the pc (the special handling of "calltrap", etc. in
446 * db_nextframe() works because the `next' pc is special).
447 */
448 actframe = frame;
449 if (first) {
450 if (tf != NULL) {
451 instr = db_get_value(pc, 4, FALSE);
452 if ((instr & 0xffffff) == 0x00e58955) {
453 /* pushl %ebp; movl %esp, %ebp */
454 actframe = (void *)(get_esp(tf) - 4);
455 } else if ((instr & 0xffff) == 0x0000e589) {
456 /* movl %esp, %ebp */
457 actframe = (void *)get_esp(tf);
458 if (tf->tf_ebp == 0) {
459 /* Fake frame better. */
460 frame = actframe;
461 }
462 } else if ((instr & 0xff) == 0x000000c3) {
463 /* ret */
464 actframe = (void *)(get_esp(tf) - 4);
465 } else if (offset == 0) {
466 /* Probably an assembler symbol. */
467 actframe = (void *)(get_esp(tf) - 4);
468 }
469 } else if (strcmp(name, "fork_trampoline") == 0) {
470 /*
471 * Don't try to walk back on a stack for a
472 * process that hasn't actually been run yet.
473 */
474 db_print_stack_entry(name, 0, 0, 0, pc,
475 actframe);
476 break;
477 }
478 first = FALSE;
479 }
480
481 argp = &actframe->f_arg0;
482 narg = MAXNARG;
483 if (sym != NULL && db_sym_numargs(sym, &narg, argnames)) {
484 argnp = argnames;
485 } else {
486 narg = db_numargs(frame);
487 }
488
489 db_print_stack_entry(name, narg, argnp, argp, pc, actframe);
490
491 if (actframe != frame) {
492 /* `frame' belongs to caller. */
493 pc = (db_addr_t)
494 db_get_value((int)&actframe->f_retaddr, 4, FALSE);
495 continue;
496 }
497
498 db_nextframe(&frame, &pc, td);
499
500 if (INKERNEL((int)pc) && !INKERNEL((int) frame)) {
501 sym = db_search_symbol(pc, DB_STGY_ANY, &offset);
502 db_symbol_values(sym, &name, NULL);
503 db_print_stack_entry(name, 0, 0, 0, pc, frame);
504 break;
505 }
506 if (!INKERNEL((int) frame)) {
507 break;
508 }
509 }
510
511 return (0);
512 }
513
514 void
515 db_trace_self(void)
516 {
517 struct i386_frame *frame;
518 db_addr_t callpc;
519 register_t ebp;
520
521 __asm __volatile("movl %%ebp,%0" : "=r" (ebp));
522 frame = (struct i386_frame *)ebp;
523 callpc = (db_addr_t)db_get_value((int)&frame->f_retaddr, 4, FALSE);
524 frame = frame->f_frame;
525 db_backtrace(curthread, NULL, frame, callpc, -1);
526 }
527
528 int
529 db_trace_thread(struct thread *thr, int count)
530 {
531 struct pcb *ctx;
532
533 ctx = kdb_thr_ctx(thr);
534 return (db_backtrace(thr, NULL, (struct i386_frame *)ctx->pcb_ebp,
535 ctx->pcb_eip, count));
536 }
537
538 int
539 i386_set_watch(watchnum, watchaddr, size, access, d)
540 int watchnum;
541 unsigned int watchaddr;
542 int size;
543 int access;
544 struct dbreg *d;
545 {
546 int i, len;
547
548 if (watchnum == -1) {
549 for (i = 0; i < 4; i++)
550 if (!DBREG_DR7_ENABLED(d->dr[7], i))
551 break;
552 if (i < 4)
553 watchnum = i;
554 else
555 return (-1);
556 }
557
558 switch (access) {
559 case DBREG_DR7_EXEC:
560 size = 1; /* size must be 1 for an execution breakpoint */
561 /* fall through */
562 case DBREG_DR7_WRONLY:
563 case DBREG_DR7_RDWR:
564 break;
565 default:
566 return (-1);
567 }
568
569 /*
570 * we can watch a 1, 2, or 4 byte sized location
571 */
572 switch (size) {
573 case 1:
574 len = DBREG_DR7_LEN_1;
575 break;
576 case 2:
577 len = DBREG_DR7_LEN_2;
578 break;
579 case 4:
580 len = DBREG_DR7_LEN_4;
581 break;
582 default:
583 return (-1);
584 }
585
586 /* clear the bits we are about to affect */
587 d->dr[7] &= ~DBREG_DR7_MASK(watchnum);
588
589 /* set drN register to the address, N=watchnum */
590 DBREG_DRX(d, watchnum) = watchaddr;
591
592 /* enable the watchpoint */
593 d->dr[7] |= DBREG_DR7_SET(watchnum, len, access,
594 DBREG_DR7_GLOBAL_ENABLE);
595
596 return (watchnum);
597 }
598
599
600 int
601 i386_clr_watch(watchnum, d)
602 int watchnum;
603 struct dbreg *d;
604 {
605
606 if (watchnum < 0 || watchnum >= 4)
607 return (-1);
608
609 d->dr[7] &= ~DBREG_DR7_MASK(watchnum);
610 DBREG_DRX(d, watchnum) = 0;
611
612 return (0);
613 }
614
615
616 int
617 db_md_set_watchpoint(addr, size)
618 db_expr_t addr;
619 db_expr_t size;
620 {
621 struct dbreg d;
622 int avail, i, wsize;
623
624 fill_dbregs(NULL, &d);
625
626 avail = 0;
627 for(i = 0; i < 4; i++) {
628 if (!DBREG_DR7_ENABLED(d.dr[7], i))
629 avail++;
630 }
631
632 if (avail * 4 < size)
633 return (-1);
634
635 for (i = 0; i < 4 && (size > 0); i++) {
636 if (!DBREG_DR7_ENABLED(d.dr[7], i)) {
637 if (size > 2)
638 wsize = 4;
639 else
640 wsize = size;
641 i386_set_watch(i, addr, wsize,
642 DBREG_DR7_WRONLY, &d);
643 addr += wsize;
644 size -= wsize;
645 }
646 }
647
648 set_dbregs(NULL, &d);
649
650 return(0);
651 }
652
653
654 int
655 db_md_clr_watchpoint(addr, size)
656 db_expr_t addr;
657 db_expr_t size;
658 {
659 struct dbreg d;
660 int i;
661
662 fill_dbregs(NULL, &d);
663
664 for(i = 0; i < 4; i++) {
665 if (DBREG_DR7_ENABLED(d.dr[7], i)) {
666 if ((DBREG_DRX((&d), i) >= addr) &&
667 (DBREG_DRX((&d), i) < addr+size))
668 i386_clr_watch(i, &d);
669
670 }
671 }
672
673 set_dbregs(NULL, &d);
674
675 return(0);
676 }
677
678
679 static const char *
680 watchtype_str(type)
681 int type;
682 {
683 switch (type) {
684 case DBREG_DR7_EXEC : return "execute"; break;
685 case DBREG_DR7_RDWR : return "read/write"; break;
686 case DBREG_DR7_WRONLY : return "write"; break;
687 default : return "invalid"; break;
688 }
689 }
690
691
692 void
693 db_md_list_watchpoints()
694 {
695 struct dbreg d;
696 int i, len, type;
697
698 fill_dbregs(NULL, &d);
699
700 db_printf("\nhardware watchpoints:\n");
701 db_printf(" watch status type len address\n");
702 db_printf(" ----- -------- ---------- --- ----------\n");
703 for (i = 0; i < 4; i++) {
704 if (DBREG_DR7_ENABLED(d.dr[7], i)) {
705 type = DBREG_DR7_ACCESS(d.dr[7], i);
706 len = DBREG_DR7_LEN(d.dr[7], i);
707 db_printf(" %-5d %-8s %10s %3d ",
708 i, "enabled", watchtype_str(type), len + 1);
709 db_printsym((db_addr_t)DBREG_DRX((&d), i), DB_STGY_ANY);
710 db_printf("\n");
711 } else {
712 db_printf(" %-5d disabled\n", i);
713 }
714 }
715
716 db_printf("\ndebug register values:\n");
717 for (i = 0; i < 8; i++) {
718 db_printf(" dr%d 0x%08x\n", i, DBREG_DRX((&d), i));
719 }
720 db_printf("\n");
721 }
722
723
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