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