Don't segfault the kernel if it can't resolve a name on a backtrace.
[dragonfly.git] / sys / platform / vkernel / i386 / db_trace.c
CommitLineData
6f7b98e0
MD
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 * $FreeBSD: src/sys/i386/i386/db_trace.c,v 1.35.2.3 2002/02/21 22:31:25 silby Exp $
27735f7d 27 * $DragonFly: src/sys/platform/vkernel/i386/db_trace.c,v 1.6 2007/02/02 15:57:51 corecode Exp $
6f7b98e0
MD
28 */
29
30#include <sys/param.h>
31#include <sys/systm.h>
32#include <sys/linker_set.h>
33#include <sys/lock.h>
34#include <sys/proc.h>
35#include <sys/reg.h>
36
37#include <machine/cpu.h>
38#include <machine/md_var.h>
39
40#include <vm/vm.h>
41#include <vm/vm_param.h>
42#include <vm/pmap.h>
43#include <vm/vm_map.h>
44#include <ddb/ddb.h>
45
46#include <sys/user.h>
47
48#include <ddb/db_access.h>
49#include <ddb/db_sym.h>
50#include <ddb/db_variables.h>
51
52db_varfcn_t db_dr0;
53db_varfcn_t db_dr1;
54db_varfcn_t db_dr2;
55db_varfcn_t db_dr3;
56db_varfcn_t db_dr4;
57db_varfcn_t db_dr5;
58db_varfcn_t db_dr6;
59db_varfcn_t db_dr7;
60
61/*
62 * Machine register set.
63 */
64struct db_variable db_regs[] = {
65 { "cs", &ddb_regs.tf_cs, FCN_NULL },
66 { "ds", &ddb_regs.tf_ds, FCN_NULL },
67 { "es", &ddb_regs.tf_es, FCN_NULL },
68 { "fs", &ddb_regs.tf_fs, FCN_NULL },
6f7b98e0 69 { "gs", &ddb_regs.tf_gs, FCN_NULL },
6f7b98e0
MD
70 { "ss", &ddb_regs.tf_ss, FCN_NULL },
71 { "eax", &ddb_regs.tf_eax, FCN_NULL },
72 { "ecx", &ddb_regs.tf_ecx, FCN_NULL },
73 { "edx", &ddb_regs.tf_edx, FCN_NULL },
74 { "ebx", &ddb_regs.tf_ebx, FCN_NULL },
75 { "esp", &ddb_regs.tf_esp, FCN_NULL },
76 { "ebp", &ddb_regs.tf_ebp, FCN_NULL },
77 { "esi", &ddb_regs.tf_esi, FCN_NULL },
78 { "edi", &ddb_regs.tf_edi, FCN_NULL },
79 { "eip", &ddb_regs.tf_eip, FCN_NULL },
80 { "efl", &ddb_regs.tf_eflags, FCN_NULL },
81 { "dr0", NULL, db_dr0 },
82 { "dr1", NULL, db_dr1 },
83 { "dr2", NULL, db_dr2 },
84 { "dr3", NULL, db_dr3 },
85 { "dr4", NULL, db_dr4 },
86 { "dr5", NULL, db_dr5 },
87 { "dr6", NULL, db_dr6 },
88 { "dr7", NULL, db_dr7 },
89};
90struct db_variable *db_eregs = db_regs + sizeof(db_regs)/sizeof(db_regs[0]);
91
92/*
93 * Stack trace.
94 */
95#define INKERNEL(va) (((vm_offset_t)(va)) >= USRSTACK)
96
97struct i386_frame {
98 struct i386_frame *f_frame;
99 int f_retaddr;
100 int f_arg0;
101};
102
103#define NORMAL 0
104#define TRAP 1
105#define INTERRUPT 2
106#define SYSCALL 3
107
108static void db_nextframe(struct i386_frame **, db_addr_t *);
109static int db_numargs(struct i386_frame *);
110static void db_print_stack_entry(const char *, int, char **, int *, db_addr_t);
111
112
113static char *watchtype_str(int type);
114static int ki386_set_watch(int watchnum, unsigned int watchaddr,
115 int size, int access, struct dbreg * d);
116static int ki386_clr_watch(int watchnum, struct dbreg * d);
117int db_md_set_watchpoint(db_expr_t addr, db_expr_t size);
118int db_md_clr_watchpoint(db_expr_t addr, db_expr_t size);
119void db_md_list_watchpoints(void);
120
121
122/*
123 * Figure out how many arguments were passed into the frame at "fp".
124 */
125static int
126db_numargs(struct i386_frame *fp)
127{
9ad680a3
MD
128 int args;
129#if 0
6f7b98e0
MD
130 int *argp;
131 int inst;
6f7b98e0
MD
132
133 argp = (int *)db_get_value((int)&fp->f_retaddr, 4, FALSE);
134 /*
135 * XXX etext is wrong for LKMs. We should attempt to interpret
136 * the instruction at the return address in all cases. This
137 * may require better fault handling.
138 */
139 if (argp < (int *)btext || argp >= (int *)etext) {
140 args = 5;
141 } else {
142 inst = db_get_value((int)argp, 4, FALSE);
143 if ((inst & 0xff) == 0x59) /* popl %ecx */
144 args = 1;
145 else if ((inst & 0xffff) == 0xc483) /* addl $Ibs, %esp */
146 args = ((inst >> 16) & 0xff) / 4;
147 else
148 args = 5;
149 }
9ad680a3
MD
150#endif
151 args = 5;
6f7b98e0
MD
152 return(args);
153}
154
155static void
156db_print_stack_entry(const char *name, int narg, char **argnp, int *argp,
157 db_addr_t callpc)
158{
159 db_printf("%s(", name);
160 while (narg) {
161 if (argnp)
162 db_printf("%s=", *argnp++);
163 db_printf("%r", db_get_value((int)argp, 4, FALSE));
164 argp++;
165 if (--narg != 0)
166 db_printf(",");
167 }
168 db_printf(") at ");
169 db_printsym(callpc, DB_STGY_PROC);
170 db_printf("\n");
171}
172
173/*
174 * Figure out the next frame up in the call stack.
175 */
176static void
177db_nextframe(struct i386_frame **fp, db_addr_t *ip)
178{
179 struct trapframe *tf;
180 int frame_type;
181 int eip, esp, ebp;
182 db_expr_t offset;
183 const char *sym, *name;
184
185 eip = db_get_value((int) &(*fp)->f_retaddr, 4, FALSE);
186 ebp = db_get_value((int) &(*fp)->f_frame, 4, FALSE);
187
188 /*
189 * Figure out frame type.
190 */
191
192 frame_type = NORMAL;
193
194 sym = db_search_symbol(eip, DB_STGY_ANY, &offset);
195 db_symbol_values(sym, &name, NULL);
196 if (name != NULL) {
197 if (!strcmp(name, "calltrap")) {
198 frame_type = TRAP;
199 } else if (!strncmp(name, "Xresume", 7)) {
200 frame_type = INTERRUPT;
201 } else if (!strcmp(name, "_Xsyscall")) {
202 frame_type = SYSCALL;
203 }
204 }
205
206 /*
207 * Normal frames need no special processing.
208 */
209 if (frame_type == NORMAL) {
210 *ip = (db_addr_t) eip;
211 *fp = (struct i386_frame *) ebp;
212 return;
213 }
214
215 db_print_stack_entry(name, 0, 0, 0, eip);
216
217 /*
218 * Point to base of trapframe which is just above the
219 * current frame.
220 */
221 tf = (struct trapframe *) ((int)*fp + 8);
222
9097944f 223#if 0
6f7b98e0 224 esp = (ISPL(tf->tf_cs) == SEL_UPL) ? tf->tf_esp : (int)&tf->tf_esp;
9097944f
MD
225#endif
226 esp = (int)&tf->tf_esp;
cced5af3 227
6f7b98e0
MD
228 switch (frame_type) {
229 case TRAP:
cced5af3 230 {
6f7b98e0
MD
231 eip = tf->tf_eip;
232 ebp = tf->tf_ebp;
233 db_printf(
234 "--- trap %#r, eip = %#r, esp = %#r, ebp = %#r ---\n",
235 tf->tf_trapno, eip, esp, ebp);
236 }
237 break;
238 case SYSCALL:
cced5af3 239 {
6f7b98e0
MD
240 eip = tf->tf_eip;
241 ebp = tf->tf_ebp;
242 db_printf(
243 "--- syscall %#r, eip = %#r, esp = %#r, ebp = %#r ---\n",
244 tf->tf_eax, eip, esp, ebp);
245 }
246 break;
247 case INTERRUPT:
248 tf = (struct trapframe *)((int)*fp + 16);
cced5af3 249 {
6f7b98e0
MD
250 eip = tf->tf_eip;
251 ebp = tf->tf_ebp;
252 db_printf(
253 "--- interrupt, eip = %#r, esp = %#r, ebp = %#r ---\n",
254 eip, esp, ebp);
255 }
256 break;
257 default:
258 break;
259 }
260
261 *ip = (db_addr_t) eip;
262 *fp = (struct i386_frame *) ebp;
263}
264
265void
266db_stack_trace_cmd(db_expr_t addr, boolean_t have_addr, db_expr_t count,
267 char *modif)
268{
269 struct i386_frame *frame;
270 int *argp;
271 db_addr_t callpc;
272 boolean_t first;
273 int i;
274
275 if (count == -1)
276 count = 1024;
277
278 if (!have_addr) {
279 frame = (struct i386_frame *)BP_REGS(&ddb_regs);
280 if (frame == NULL)
281 frame = (struct i386_frame *)(SP_REGS(&ddb_regs) - 4);
282 callpc = PC_REGS(&ddb_regs);
6f7b98e0
MD
283 } else {
284 /*
285 * Look for something that might be a frame pointer, just as
286 * a convenience.
287 */
288 frame = (struct i386_frame *)addr;
289 for (i = 0; i < 4096; i += 4) {
290 struct i386_frame *check;
291
292 check = (struct i386_frame *)db_get_value((int)((char *)&frame->f_frame + i), 4, FALSE);
293 if ((char *)check - (char *)frame >= 0 &&
294 (char *)check - (char *)frame < 4096
295 ) {
296 break;
297 }
298 db_printf("%p does not look like a stack frame, skipping\n", (char *)&frame->f_frame + i);
299 }
300 if (i == 4096) {
301 db_printf("Unable to find anything that looks like a stack frame\n");
302 return;
303 }
304 frame = (void *)((char *)frame + i);
305 db_printf("Trace beginning at frame %p\n", frame);
306 callpc = (db_addr_t)db_get_value((int)&frame->f_retaddr, 4, FALSE);
307 }
308
309 first = TRUE;
310 while (count--) {
311 struct i386_frame *actframe;
312 int narg;
313 const char * name;
314 db_expr_t offset;
315 c_db_sym_t sym;
316#define MAXNARG 16
317 char *argnames[MAXNARG], **argnp = NULL;
318
319 sym = db_search_symbol(callpc, DB_STGY_ANY, &offset);
320 db_symbol_values(sym, &name, NULL);
321
322 /*
323 * Attempt to determine a (possibly fake) frame that gives
324 * the caller's pc. It may differ from `frame' if the
325 * current function never sets up a standard frame or hasn't
326 * set one up yet or has just discarded one. The last two
327 * cases can be guessed fairly reliably for code generated
328 * by gcc. The first case is too much trouble to handle in
329 * general because the amount of junk on the stack depends
330 * on the pc (the special handling of "calltrap", etc. in
331 * db_nextframe() works because the `next' pc is special).
332 */
333 actframe = frame;
334 if (first) {
335 if (!have_addr) {
336 int instr;
337
338 instr = db_get_value(callpc, 4, FALSE);
339 if ((instr & 0x00ffffff) == 0x00e58955) {
340 /* pushl %ebp; movl %esp, %ebp */
341 actframe = (struct i386_frame *)
342 (SP_REGS(&ddb_regs) - 4);
343 } else if ((instr & 0x0000ffff) == 0x0000e589) {
344 /* movl %esp, %ebp */
345 actframe = (struct i386_frame *)
346 SP_REGS(&ddb_regs);
347 if (ddb_regs.tf_ebp == 0) {
348 /* Fake caller's frame better. */
349 frame = actframe;
350 }
351 } else if ((instr & 0x000000ff) == 0x000000c3) {
352 /* ret */
353 actframe = (struct i386_frame *)
354 (SP_REGS(&ddb_regs) - 4);
355 } else if (offset == 0) {
356 /* Probably a symbol in assembler code. */
357 actframe = (struct i386_frame *)
358 (SP_REGS(&ddb_regs) - 4);
359 }
27735f7d
SS
360 } else if (name != NULL &&
361 strcmp(name, "fork_trampoline") == 0) {
6f7b98e0
MD
362 /*
363 * Don't try to walk back on a stack for a
364 * process that hasn't actually been run yet.
365 */
366 db_print_stack_entry(name, 0, 0, 0, callpc);
367 break;
368 }
369 first = FALSE;
370 }
371
372 argp = &actframe->f_arg0;
373 narg = MAXNARG;
374 if (sym != NULL && db_sym_numargs(sym, &narg, argnames)) {
375 argnp = argnames;
376 } else {
377 narg = db_numargs(frame);
378 }
379
380 db_print_stack_entry(name, narg, argnp, argp, callpc);
381
382 if (actframe != frame) {
383 /* `frame' belongs to caller. */
384 callpc = (db_addr_t)
385 db_get_value((int)&actframe->f_retaddr, 4, FALSE);
386 continue;
387 }
388
389 db_nextframe(&frame, &callpc);
390
cced5af3 391 {
6f7b98e0
MD
392 sym = db_search_symbol(callpc, DB_STGY_ANY, &offset);
393 db_symbol_values(sym, &name, NULL);
394 db_print_stack_entry(name, 0, 0, 0, callpc);
395 break;
396 }
cced5af3 397 if (frame == 0)
6f7b98e0 398 break;
6f7b98e0
MD
399 }
400}
401
402void
403db_print_backtrace(void)
404{
405 register_t ebp;
406
407 __asm __volatile("movl %%ebp, %0" : "=r" (ebp));
408 db_stack_trace_cmd(ebp, 1, -1, NULL);
409}
410
411#define DB_DRX_FUNC(reg) \
412int \
413db_ ## reg (struct db_variable *vp, db_expr_t *valuep, int op) \
414{ \
415 if (op == DB_VAR_GET) \
416 *valuep = r ## reg (); \
417 else \
418 load_ ## reg (*valuep); \
419 \
420 return(0); \
421}
422
423DB_DRX_FUNC(dr0)
424DB_DRX_FUNC(dr1)
425DB_DRX_FUNC(dr2)
426DB_DRX_FUNC(dr3)
427DB_DRX_FUNC(dr4)
428DB_DRX_FUNC(dr5)
429DB_DRX_FUNC(dr6)
430DB_DRX_FUNC(dr7)
431
432static int
433ki386_set_watch(int watchnum, unsigned int watchaddr, int size, int access,
434 struct dbreg *d)
435{
436 int i;
437 unsigned int mask;
438
439 if (watchnum == -1) {
440 for (i = 0, mask = 0x3; i < 4; i++, mask <<= 2)
441 if ((d->dr7 & mask) == 0)
442 break;
443 if (i < 4)
444 watchnum = i;
445 else
446 return(-1);
447 }
448
449 switch (access) {
450 case DBREG_DR7_EXEC:
451 size = 1; /* size must be 1 for an execution breakpoint */
452 /* fall through */
453 case DBREG_DR7_WRONLY:
454 case DBREG_DR7_RDWR:
455 break;
456 default:
457 return(-1);
458 }
459
460 /*
461 * we can watch a 1, 2, or 4 byte sized location
462 */
463 switch (size) {
464 case 1:
465 mask = 0x00;
466 break;
467 case 2:
468 mask = 0x01 << 2;
469 break;
470 case 4:
471 mask = 0x03 << 2;
472 break;
473 default:
474 return(-1);
475 }
476
477 mask |= access;
478
479 /* clear the bits we are about to affect */
480 d->dr7 &= ~((0x3 << (watchnum * 2)) | (0x0f << (watchnum * 4 + 16)));
481
482 /* set drN register to the address, N=watchnum */
483 DBREG_DRX(d, watchnum) = watchaddr;
484
485 /* enable the watchpoint */
486 d->dr7 |= (0x2 << (watchnum * 2)) | (mask << (watchnum * 4 + 16));
487
488 return(watchnum);
489}
490
491
492int
493ki386_clr_watch(int watchnum, struct dbreg *d)
494{
495 if (watchnum < 0 || watchnum >= 4)
496 return(-1);
497
498 d->dr7 &= ~((0x3 << (watchnum * 2)) | (0x0f << (watchnum * 4 + 16)));
499 DBREG_DRX(d, watchnum) = 0;
500
501 return(0);
502}
503
504
505int
506db_md_set_watchpoint(db_expr_t addr, db_expr_t size)
507{
508 int avail, wsize;
509 int i;
510 struct dbreg d;
511
512 fill_dbregs(NULL, &d);
513
514 avail = 0;
515 for(i=0; i < 4; i++) {
516 if ((d.dr7 & (3 << (i * 2))) == 0)
517 avail++;
518 }
519
520 if (avail * 4 < size)
521 return(-1);
522
523 for (i=0; i < 4 && (size != 0); i++) {
524 if ((d.dr7 & (3 << (i * 2))) == 0) {
525 if (size > 4)
526 wsize = 4;
527 else
528 wsize = size;
529 if (wsize == 3)
530 wsize++;
531 ki386_set_watch(i, addr, wsize, DBREG_DR7_WRONLY, &d);
532 addr += wsize;
533 size -= wsize;
534 }
535 }
536
537 set_dbregs(NULL, &d);
538
539 return(0);
540}
541
542int
543db_md_clr_watchpoint(db_expr_t addr, db_expr_t size)
544{
545 int i;
546 struct dbreg d;
547
548 fill_dbregs(NULL, &d);
549
550 for(i=0; i<4; i++) {
551 if (d.dr7 & (3 << (i * 2))) {
552 if ((DBREG_DRX((&d), i) >= addr) &&
553 (DBREG_DRX((&d), i) < addr + size))
554 ki386_clr_watch(i, &d);
555 }
556 }
557
558 set_dbregs(NULL, &d);
559
560 return(0);
561}
562
563static char *
564watchtype_str(int type)
565{
566 switch (type) {
567 case DBREG_DR7_EXEC:
568 return "execute";
569 case DBREG_DR7_RDWR:
570 return "read/write";
571 case DBREG_DR7_WRONLY:
572 return "write";
573 default:
574 return "invalid";
575 }
576}
577
578void
579db_md_list_watchpoints(void)
580{
581 int i;
582 struct dbreg d;
583
584 fill_dbregs(NULL, &d);
585
586 db_printf("\nhardware watchpoints:\n");
587 db_printf(" watch status type len address\n"
588 " ----- -------- ---------- --- ----------\n");
589 for (i=0; i < 4; i++) {
590 if (d.dr7 & (0x03 << (i * 2))) {
591 unsigned type, len;
592 type = (d.dr7 >> (16 + (i * 4))) & 3;
593 len = (d.dr7 >> (16 + (i * 4) + 2)) & 3;
594 db_printf(" %-5d %-8s %10s %3d 0x%08x\n",
595 i, "enabled", watchtype_str(type),
596 len + 1, DBREG_DRX((&d), i));
597 } else {
598 db_printf(" %-5d disabled\n", i);
599 }
600 }
601
602 db_printf("\ndebug register values:\n");
603 for (i=0; i < 8; i++)
604 db_printf(" dr%d 0x%08x\n", i, DBREG_DRX((&d),i));
605 db_printf("\n");
606}