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/10.4/sys/amd64/amd64/db_trace.c 290731 2015-11-12 23:49:47Z jhb $");
29
30 #include "opt_compat.h"
31
32 #include <sys/param.h>
33 #include <sys/systm.h>
34 #include <sys/kdb.h>
35 #include <sys/proc.h>
36 #include <sys/smp.h>
37 #include <sys/stack.h>
38 #include <sys/sysent.h>
39
40 #include <machine/cpu.h>
41 #include <machine/md_var.h>
42 #include <machine/pcb.h>
43 #include <machine/reg.h>
44 #include <machine/stack.h>
45
46 #include <vm/vm.h>
47 #include <vm/vm_param.h>
48 #include <vm/pmap.h>
49
50 #include <ddb/ddb.h>
51 #include <ddb/db_access.h>
52 #include <ddb/db_sym.h>
53 #include <ddb/db_variables.h>
54
55 static db_varfcn_t db_frame;
56 static db_varfcn_t db_frame_seg;
57
58 CTASSERT(sizeof(struct dbreg) == sizeof(((struct pcpu *)NULL)->pc_dbreg));
59
60 /*
61 * Machine register set.
62 */
63 #define DB_OFFSET(x) (db_expr_t *)offsetof(struct trapframe, x)
64 struct db_variable db_regs[] = {
65 { "cs", DB_OFFSET(tf_cs), db_frame_seg },
66 { "ds", DB_OFFSET(tf_ds), db_frame_seg },
67 { "es", DB_OFFSET(tf_es), db_frame_seg },
68 { "fs", DB_OFFSET(tf_fs), db_frame_seg },
69 { "gs", DB_OFFSET(tf_gs), db_frame_seg },
70 { "ss", DB_OFFSET(tf_ss), db_frame_seg },
71 { "rax", DB_OFFSET(tf_rax), db_frame },
72 { "rcx", DB_OFFSET(tf_rcx), db_frame },
73 { "rdx", DB_OFFSET(tf_rdx), db_frame },
74 { "rbx", DB_OFFSET(tf_rbx), db_frame },
75 { "rsp", DB_OFFSET(tf_rsp), db_frame },
76 { "rbp", DB_OFFSET(tf_rbp), db_frame },
77 { "rsi", DB_OFFSET(tf_rsi), db_frame },
78 { "rdi", DB_OFFSET(tf_rdi), db_frame },
79 { "r8", DB_OFFSET(tf_r8), db_frame },
80 { "r9", DB_OFFSET(tf_r9), db_frame },
81 { "r10", DB_OFFSET(tf_r10), db_frame },
82 { "r11", DB_OFFSET(tf_r11), db_frame },
83 { "r12", DB_OFFSET(tf_r12), db_frame },
84 { "r13", DB_OFFSET(tf_r13), db_frame },
85 { "r14", DB_OFFSET(tf_r14), db_frame },
86 { "r15", DB_OFFSET(tf_r15), db_frame },
87 { "rip", DB_OFFSET(tf_rip), db_frame },
88 { "rflags", DB_OFFSET(tf_rflags), db_frame },
89 };
90 struct db_variable *db_eregs = db_regs + nitems(db_regs);
91
92 static int
93 db_frame_seg(struct db_variable *vp, db_expr_t *valuep, int op)
94 {
95 uint16_t *reg;
96
97 if (kdb_frame == NULL)
98 return (0);
99
100 reg = (uint16_t *)((uintptr_t)kdb_frame + (db_expr_t)vp->valuep);
101 if (op == DB_VAR_GET)
102 *valuep = *reg;
103 else
104 *reg = *valuep;
105 return (1);
106 }
107
108 static int
109 db_frame(struct db_variable *vp, db_expr_t *valuep, int op)
110 {
111 long *reg;
112
113 if (kdb_frame == NULL)
114 return (0);
115
116 reg = (long *)((uintptr_t)kdb_frame + (db_expr_t)vp->valuep);
117 if (op == DB_VAR_GET)
118 *valuep = *reg;
119 else
120 *reg = *valuep;
121 return (1);
122 }
123
124 #define NORMAL 0
125 #define TRAP 1
126 #define INTERRUPT 2
127 #define SYSCALL 3
128 #define TRAP_INTERRUPT 5
129
130 static void db_nextframe(struct amd64_frame **, db_addr_t *, struct thread *);
131 static void db_print_stack_entry(const char *, db_addr_t, void *);
132 static void decode_syscall(int, struct thread *);
133
134 static const char * watchtype_str(int type);
135 int amd64_set_watch(int watchnum, unsigned long watchaddr, int size,
136 int access, struct dbreg *d);
137 int amd64_clr_watch(int watchnum, struct dbreg *d);
138
139 static void
140 db_print_stack_entry(const char *name, db_addr_t callpc, void *frame)
141 {
142
143 db_printf("%s() at ", name != NULL ? name : "??");
144 db_printsym(callpc, DB_STGY_PROC);
145 if (frame != NULL)
146 db_printf("/frame 0x%lx", (register_t)frame);
147 db_printf("\n");
148 }
149
150 static void
151 decode_syscall(int number, struct thread *td)
152 {
153 struct proc *p;
154 c_db_sym_t sym;
155 db_expr_t diff;
156 sy_call_t *f;
157 const char *symname;
158
159 db_printf(" (%d", number);
160 p = (td != NULL) ? td->td_proc : NULL;
161 if (p != NULL && 0 <= number && number < p->p_sysent->sv_size) {
162 f = p->p_sysent->sv_table[number].sy_call;
163 sym = db_search_symbol((db_addr_t)f, DB_STGY_ANY, &diff);
164 if (sym != DB_SYM_NULL && diff == 0) {
165 db_symbol_values(sym, &symname, NULL);
166 db_printf(", %s, %s", p->p_sysent->sv_name, symname);
167 }
168 }
169 db_printf(")");
170 }
171
172 /*
173 * Figure out the next frame up in the call stack.
174 */
175 static void
176 db_nextframe(struct amd64_frame **fp, db_addr_t *ip, struct thread *td)
177 {
178 struct trapframe *tf;
179 int frame_type;
180 long rip, rsp, rbp;
181 db_expr_t offset;
182 c_db_sym_t sym;
183 const char *name;
184
185 rip = db_get_value((long) &(*fp)->f_retaddr, 8, FALSE);
186 rbp = db_get_value((long) &(*fp)->f_frame, 8, FALSE);
187
188 /*
189 * Figure out frame type. We look at the address just before
190 * the saved instruction pointer as the saved EIP is after the
191 * call function, and if the function being called is marked as
192 * dead (such as panic() at the end of dblfault_handler()), then
193 * the instruction at the saved EIP will be part of a different
194 * function (syscall() in this example) rather than the one that
195 * actually made the call.
196 */
197 frame_type = NORMAL;
198 sym = db_search_symbol(rip - 1, DB_STGY_ANY, &offset);
199 db_symbol_values(sym, &name, NULL);
200 if (name != NULL) {
201 if (strcmp(name, "calltrap") == 0 ||
202 strcmp(name, "fork_trampoline") == 0 ||
203 strcmp(name, "nmi_calltrap") == 0 ||
204 strcmp(name, "Xdblfault") == 0)
205 frame_type = TRAP;
206 else if (strncmp(name, "Xatpic_intr", 11) == 0 ||
207 strncmp(name, "Xapic_isr", 9) == 0 ||
208 strcmp(name, "Xtimerint") == 0 ||
209 strcmp(name, "Xipi_intr_bitmap_handler") == 0 ||
210 strcmp(name, "Xcpustop") == 0 ||
211 strcmp(name, "Xcpususpend") == 0 ||
212 strcmp(name, "Xrendezvous") == 0)
213 frame_type = INTERRUPT;
214 else if (strcmp(name, "Xfast_syscall") == 0)
215 frame_type = SYSCALL;
216 #ifdef COMPAT_FREEBSD32
217 else if (strcmp(name, "Xint0x80_syscall") == 0)
218 frame_type = SYSCALL;
219 #endif
220 /* XXX: These are interrupts with trap frames. */
221 else if (strcmp(name, "Xtimerint") == 0 ||
222 strcmp(name, "Xcpustop") == 0 ||
223 strcmp(name, "Xcpususpend") == 0 ||
224 strcmp(name, "Xrendezvous") == 0 ||
225 strcmp(name, "Xipi_intr_bitmap_handler") == 0)
226 frame_type = TRAP_INTERRUPT;
227 }
228
229 /*
230 * Normal frames need no special processing.
231 */
232 if (frame_type == NORMAL) {
233 *ip = (db_addr_t) rip;
234 *fp = (struct amd64_frame *) rbp;
235 return;
236 }
237
238 db_print_stack_entry(name, rip, &(*fp)->f_frame);
239
240 /*
241 * Point to base of trapframe which is just above the
242 * current frame.
243 */
244 tf = (struct trapframe *)((long)*fp + 16);
245
246 if (INKERNEL((long) tf)) {
247 rsp = tf->tf_rsp;
248 rip = tf->tf_rip;
249 rbp = tf->tf_rbp;
250 switch (frame_type) {
251 case TRAP:
252 db_printf("--- trap %#r", tf->tf_trapno);
253 break;
254 case SYSCALL:
255 db_printf("--- syscall");
256 decode_syscall(tf->tf_rax, td);
257 break;
258 case TRAP_INTERRUPT:
259 case INTERRUPT:
260 db_printf("--- interrupt");
261 break;
262 default:
263 panic("The moon has moved again.");
264 }
265 db_printf(", rip = %#lr, rsp = %#lr, rbp = %#lr ---\n", rip,
266 rsp, rbp);
267 }
268
269 *ip = (db_addr_t) rip;
270 *fp = (struct amd64_frame *) rbp;
271 }
272
273 static int
274 db_backtrace(struct thread *td, struct trapframe *tf, struct amd64_frame *frame,
275 db_addr_t pc, register_t sp, int count)
276 {
277 struct amd64_frame *actframe;
278 const char *name;
279 db_expr_t offset;
280 c_db_sym_t sym;
281 boolean_t first;
282
283 if (count == -1)
284 count = 1024;
285
286 first = TRUE;
287 while (count-- && !db_pager_quit) {
288 sym = db_search_symbol(pc, DB_STGY_ANY, &offset);
289 db_symbol_values(sym, &name, NULL);
290
291 /*
292 * Attempt to determine a (possibly fake) frame that gives
293 * the caller's pc. It may differ from `frame' if the
294 * current function never sets up a standard frame or hasn't
295 * set one up yet or has just discarded one. The last two
296 * cases can be guessed fairly reliably for code generated
297 * by gcc. The first case is too much trouble to handle in
298 * general because the amount of junk on the stack depends
299 * on the pc (the special handling of "calltrap", etc. in
300 * db_nextframe() works because the `next' pc is special).
301 */
302 actframe = frame;
303 if (first) {
304 first = FALSE;
305 if (sym == C_DB_SYM_NULL && sp != 0) {
306 /*
307 * If a symbol couldn't be found, we've probably
308 * jumped to a bogus location, so try and use
309 * the return address to find our caller.
310 */
311 db_print_stack_entry(name, pc, NULL);
312 pc = db_get_value(sp, 8, FALSE);
313 if (db_search_symbol(pc, DB_STGY_PROC,
314 &offset) == C_DB_SYM_NULL)
315 break;
316 continue;
317 } else if (tf != NULL) {
318 int instr;
319
320 instr = db_get_value(pc, 4, FALSE);
321 if ((instr & 0xffffffff) == 0xe5894855) {
322 /* pushq %rbp; movq %rsp, %rbp */
323 actframe = (void *)(tf->tf_rsp - 8);
324 } else if ((instr & 0xffffff) == 0xe58948) {
325 /* movq %rsp, %rbp */
326 actframe = (void *)tf->tf_rsp;
327 if (tf->tf_rbp == 0) {
328 /* Fake frame better. */
329 frame = actframe;
330 }
331 } else if ((instr & 0xff) == 0xc3) {
332 /* ret */
333 actframe = (void *)(tf->tf_rsp - 8);
334 } else if (offset == 0) {
335 /* Probably an assembler symbol. */
336 actframe = (void *)(tf->tf_rsp - 8);
337 }
338 } else if (strcmp(name, "fork_trampoline") == 0) {
339 /*
340 * Don't try to walk back on a stack for a
341 * process that hasn't actually been run yet.
342 */
343 db_print_stack_entry(name, pc, actframe);
344 break;
345 }
346 }
347
348 db_print_stack_entry(name, pc, actframe);
349
350 if (actframe != frame) {
351 /* `frame' belongs to caller. */
352 pc = (db_addr_t)
353 db_get_value((long)&actframe->f_retaddr, 8, FALSE);
354 continue;
355 }
356
357 db_nextframe(&frame, &pc, td);
358
359 if (INKERNEL((long)pc) && !INKERNEL((long)frame)) {
360 sym = db_search_symbol(pc, DB_STGY_ANY, &offset);
361 db_symbol_values(sym, &name, NULL);
362 db_print_stack_entry(name, pc, frame);
363 break;
364 }
365 if (!INKERNEL((long) frame)) {
366 break;
367 }
368 }
369
370 return (0);
371 }
372
373 void
374 db_trace_self(void)
375 {
376 struct amd64_frame *frame;
377 db_addr_t callpc;
378 register_t rbp;
379
380 __asm __volatile("movq %%rbp,%0" : "=r" (rbp));
381 frame = (struct amd64_frame *)rbp;
382 callpc = (db_addr_t)db_get_value((long)&frame->f_retaddr, 8, FALSE);
383 frame = frame->f_frame;
384 db_backtrace(curthread, NULL, frame, callpc, 0, -1);
385 }
386
387 int
388 db_trace_thread(struct thread *thr, int count)
389 {
390 struct pcb *ctx;
391 struct trapframe *tf;
392
393 ctx = kdb_thr_ctx(thr);
394 tf = thr == kdb_thread ? kdb_frame : NULL;
395 return (db_backtrace(thr, tf, (struct amd64_frame *)ctx->pcb_rbp,
396 ctx->pcb_rip, ctx->pcb_rsp, count));
397 }
398
399 int
400 amd64_set_watch(watchnum, watchaddr, size, access, d)
401 int watchnum;
402 unsigned long watchaddr;
403 int size;
404 int access;
405 struct dbreg *d;
406 {
407 int i, len;
408
409 if (watchnum == -1) {
410 for (i = 0; i < 4; i++)
411 if (!DBREG_DR7_ENABLED(d->dr[7], i))
412 break;
413 if (i < 4)
414 watchnum = i;
415 else
416 return (-1);
417 }
418
419 switch (access) {
420 case DBREG_DR7_EXEC:
421 size = 1; /* size must be 1 for an execution breakpoint */
422 /* fall through */
423 case DBREG_DR7_WRONLY:
424 case DBREG_DR7_RDWR:
425 break;
426 default:
427 return (-1);
428 }
429
430 /*
431 * we can watch a 1, 2, 4, or 8 byte sized location
432 */
433 switch (size) {
434 case 1:
435 len = DBREG_DR7_LEN_1;
436 break;
437 case 2:
438 len = DBREG_DR7_LEN_2;
439 break;
440 case 4:
441 len = DBREG_DR7_LEN_4;
442 break;
443 case 8:
444 len = DBREG_DR7_LEN_8;
445 break;
446 default:
447 return (-1);
448 }
449
450 /* clear the bits we are about to affect */
451 d->dr[7] &= ~DBREG_DR7_MASK(watchnum);
452
453 /* set drN register to the address, N=watchnum */
454 DBREG_DRX(d, watchnum) = watchaddr;
455
456 /* enable the watchpoint */
457 d->dr[7] |= DBREG_DR7_SET(watchnum, len, access,
458 DBREG_DR7_GLOBAL_ENABLE);
459
460 return (watchnum);
461 }
462
463
464 int
465 amd64_clr_watch(watchnum, d)
466 int watchnum;
467 struct dbreg *d;
468 {
469
470 if (watchnum < 0 || watchnum >= 4)
471 return (-1);
472
473 d->dr[7] &= ~DBREG_DR7_MASK(watchnum);
474 DBREG_DRX(d, watchnum) = 0;
475
476 return (0);
477 }
478
479
480 int
481 db_md_set_watchpoint(addr, size)
482 db_expr_t addr;
483 db_expr_t size;
484 {
485 struct dbreg *d;
486 struct pcpu *pc;
487 int avail, c, cpu, i, wsize;
488
489 d = (struct dbreg *)PCPU_PTR(dbreg);
490 cpu = PCPU_GET(cpuid);
491 fill_dbregs(NULL, d);
492
493 avail = 0;
494 for (i = 0; i < 4; i++) {
495 if (!DBREG_DR7_ENABLED(d->dr[7], i))
496 avail++;
497 }
498
499 if (avail * 8 < size)
500 return (-1);
501
502 for (i = 0; i < 4 && size > 0; i++) {
503 if (!DBREG_DR7_ENABLED(d->dr[7], i)) {
504 if (size >= 8 || (avail == 1 && size > 4))
505 wsize = 8;
506 else if (size > 2)
507 wsize = 4;
508 else
509 wsize = size;
510 amd64_set_watch(i, addr, wsize, DBREG_DR7_WRONLY, d);
511 addr += wsize;
512 size -= wsize;
513 avail--;
514 }
515 }
516
517 set_dbregs(NULL, d);
518 CPU_FOREACH(c) {
519 if (c == cpu)
520 continue;
521 pc = pcpu_find(c);
522 memcpy(pc->pc_dbreg, d, sizeof(*d));
523 pc->pc_dbreg_cmd = PC_DBREG_CMD_LOAD;
524 }
525
526 return (0);
527 }
528
529 int
530 db_md_clr_watchpoint(addr, size)
531 db_expr_t addr;
532 db_expr_t size;
533 {
534 struct dbreg *d;
535 struct pcpu *pc;
536 int i, c, cpu;
537
538 d = (struct dbreg *)PCPU_PTR(dbreg);
539 cpu = PCPU_GET(cpuid);
540 fill_dbregs(NULL, d);
541
542 for (i = 0; i < 4; i++) {
543 if (DBREG_DR7_ENABLED(d->dr[7], i)) {
544 if (DBREG_DRX((d), i) >= addr &&
545 DBREG_DRX((d), i) < addr + size)
546 amd64_clr_watch(i, d);
547
548 }
549 }
550
551 set_dbregs(NULL, d);
552 CPU_FOREACH(c) {
553 if (c == cpu)
554 continue;
555 pc = pcpu_find(c);
556 memcpy(pc->pc_dbreg, d, sizeof(*d));
557 pc->pc_dbreg_cmd = PC_DBREG_CMD_LOAD;
558 }
559
560 return (0);
561 }
562
563
564 static const char *
565 watchtype_str(type)
566 int type;
567 {
568 switch (type) {
569 case DBREG_DR7_EXEC : return "execute"; break;
570 case DBREG_DR7_RDWR : return "read/write"; break;
571 case DBREG_DR7_WRONLY : return "write"; break;
572 default : return "invalid"; break;
573 }
574 }
575
576
577 void
578 db_md_list_watchpoints()
579 {
580 struct dbreg d;
581 int i, len, type;
582
583 fill_dbregs(NULL, &d);
584
585 db_printf("\nhardware watchpoints:\n");
586 db_printf(" watch status type len address\n");
587 db_printf(" ----- -------- ---------- --- ------------------\n");
588 for (i = 0; i < 4; i++) {
589 if (DBREG_DR7_ENABLED(d.dr[7], i)) {
590 type = DBREG_DR7_ACCESS(d.dr[7], i);
591 len = DBREG_DR7_LEN(d.dr[7], i);
592 if (len == DBREG_DR7_LEN_8)
593 len = 8;
594 else
595 len++;
596 db_printf(" %-5d %-8s %10s %3d ",
597 i, "enabled", watchtype_str(type), len);
598 db_printsym((db_addr_t)DBREG_DRX((&d), i), DB_STGY_ANY);
599 db_printf("\n");
600 } else {
601 db_printf(" %-5d disabled\n", i);
602 }
603 }
604
605 db_printf("\ndebug register values:\n");
606 for (i = 0; i < 8; i++) {
607 db_printf(" dr%d 0x%016lx\n", i, DBREG_DRX((&d), i));
608 }
609 db_printf("\n");
610 }
611
612 void
613 amd64_db_resume_dbreg(void)
614 {
615 struct dbreg *d;
616
617 switch (PCPU_GET(dbreg_cmd)) {
618 case PC_DBREG_CMD_LOAD:
619 d = (struct dbreg *)PCPU_PTR(dbreg);
620 set_dbregs(NULL, d);
621 PCPU_SET(dbreg_cmd, PC_DBREG_CMD_NONE);
622 break;
623 }
624 }
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