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 "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, "mchk_calltrap") == 0 ||
204 strcmp(name, "nmi_calltrap") == 0 ||
205 strcmp(name, "Xdblfault") == 0)
206 frame_type = TRAP;
207 else if (strncmp(name, "Xatpic_intr", 11) == 0 ||
208 strncmp(name, "Xapic_isr", 9) == 0 ||
209 strcmp(name, "Xxen_intr_upcall") == 0 ||
210 strcmp(name, "Xtimerint") == 0 ||
211 strcmp(name, "Xipi_intr_bitmap_handler") == 0 ||
212 strcmp(name, "Xcpustop") == 0 ||
213 strcmp(name, "Xcpususpend") == 0 ||
214 strcmp(name, "Xrendezvous") == 0)
215 frame_type = INTERRUPT;
216 else if (strcmp(name, "Xfast_syscall") == 0 ||
217 strcmp(name, "Xfast_syscall_pti") == 0 ||
218 strcmp(name, "fast_syscall_common") == 0)
219 frame_type = SYSCALL;
220 #ifdef COMPAT_FREEBSD32
221 else if (strcmp(name, "Xint0x80_syscall") == 0)
222 frame_type = SYSCALL;
223 #endif
224 /* XXX: These are interrupts with trap frames. */
225 else if (strcmp(name, "Xtimerint") == 0 ||
226 strcmp(name, "Xcpustop") == 0 ||
227 strcmp(name, "Xcpususpend") == 0 ||
228 strcmp(name, "Xrendezvous") == 0 ||
229 strcmp(name, "Xipi_intr_bitmap_handler") == 0)
230 frame_type = TRAP_INTERRUPT;
231 }
232
233 /*
234 * Normal frames need no special processing.
235 */
236 if (frame_type == NORMAL) {
237 *ip = (db_addr_t) rip;
238 *fp = (struct amd64_frame *) rbp;
239 return;
240 }
241
242 db_print_stack_entry(name, rip, &(*fp)->f_frame);
243
244 /*
245 * Point to base of trapframe which is just above the
246 * current frame.
247 */
248 tf = (struct trapframe *)((long)*fp + 16);
249
250 if (INKERNEL((long) tf)) {
251 rsp = tf->tf_rsp;
252 rip = tf->tf_rip;
253 rbp = tf->tf_rbp;
254 switch (frame_type) {
255 case TRAP:
256 db_printf("--- trap %#r", tf->tf_trapno);
257 break;
258 case SYSCALL:
259 db_printf("--- syscall");
260 decode_syscall(tf->tf_rax, td);
261 break;
262 case TRAP_INTERRUPT:
263 case INTERRUPT:
264 db_printf("--- interrupt");
265 break;
266 default:
267 panic("The moon has moved again.");
268 }
269 db_printf(", rip = %#lr, rsp = %#lr, rbp = %#lr ---\n", rip,
270 rsp, rbp);
271 }
272
273 *ip = (db_addr_t) rip;
274 *fp = (struct amd64_frame *) rbp;
275 }
276
277 static int
278 db_backtrace(struct thread *td, struct trapframe *tf, struct amd64_frame *frame,
279 db_addr_t pc, register_t sp, int count)
280 {
281 struct amd64_frame *actframe;
282 const char *name;
283 db_expr_t offset;
284 c_db_sym_t sym;
285 boolean_t first;
286
287 if (count == -1)
288 count = 1024;
289
290 first = TRUE;
291 while (count-- && !db_pager_quit) {
292 sym = db_search_symbol(pc, DB_STGY_ANY, &offset);
293 db_symbol_values(sym, &name, NULL);
294
295 /*
296 * Attempt to determine a (possibly fake) frame that gives
297 * the caller's pc. It may differ from `frame' if the
298 * current function never sets up a standard frame or hasn't
299 * set one up yet or has just discarded one. The last two
300 * cases can be guessed fairly reliably for code generated
301 * by gcc. The first case is too much trouble to handle in
302 * general because the amount of junk on the stack depends
303 * on the pc (the special handling of "calltrap", etc. in
304 * db_nextframe() works because the `next' pc is special).
305 */
306 actframe = frame;
307 if (first) {
308 first = FALSE;
309 if (sym == C_DB_SYM_NULL && sp != 0) {
310 /*
311 * If a symbol couldn't be found, we've probably
312 * jumped to a bogus location, so try and use
313 * the return address to find our caller.
314 */
315 db_print_stack_entry(name, pc, NULL);
316 pc = db_get_value(sp, 8, FALSE);
317 if (db_search_symbol(pc, DB_STGY_PROC,
318 &offset) == C_DB_SYM_NULL)
319 break;
320 continue;
321 } else if (tf != NULL) {
322 int instr;
323
324 instr = db_get_value(pc, 4, FALSE);
325 if ((instr & 0xffffffff) == 0xe5894855) {
326 /* pushq %rbp; movq %rsp, %rbp */
327 actframe = (void *)(tf->tf_rsp - 8);
328 } else if ((instr & 0xffffff) == 0xe58948) {
329 /* movq %rsp, %rbp */
330 actframe = (void *)tf->tf_rsp;
331 if (tf->tf_rbp == 0) {
332 /* Fake frame better. */
333 frame = actframe;
334 }
335 } else if ((instr & 0xff) == 0xc3) {
336 /* ret */
337 actframe = (void *)(tf->tf_rsp - 8);
338 } else if (offset == 0) {
339 /* Probably an assembler symbol. */
340 actframe = (void *)(tf->tf_rsp - 8);
341 }
342 } else if (name != NULL &&
343 strcmp(name, "fork_trampoline") == 0) {
344 /*
345 * Don't try to walk back on a stack for a
346 * process that hasn't actually been run yet.
347 */
348 db_print_stack_entry(name, pc, actframe);
349 break;
350 }
351 }
352
353 db_print_stack_entry(name, pc, actframe);
354
355 if (actframe != frame) {
356 /* `frame' belongs to caller. */
357 pc = (db_addr_t)
358 db_get_value((long)&actframe->f_retaddr, 8, FALSE);
359 continue;
360 }
361
362 db_nextframe(&frame, &pc, td);
363
364 if (INKERNEL((long)pc) && !INKERNEL((long)frame)) {
365 sym = db_search_symbol(pc, DB_STGY_ANY, &offset);
366 db_symbol_values(sym, &name, NULL);
367 db_print_stack_entry(name, pc, frame);
368 break;
369 }
370 if (!INKERNEL((long) frame)) {
371 break;
372 }
373 }
374
375 return (0);
376 }
377
378 void
379 db_trace_self(void)
380 {
381 struct amd64_frame *frame;
382 db_addr_t callpc;
383 register_t rbp;
384
385 __asm __volatile("movq %%rbp,%0" : "=r" (rbp));
386 frame = (struct amd64_frame *)rbp;
387 callpc = (db_addr_t)db_get_value((long)&frame->f_retaddr, 8, FALSE);
388 frame = frame->f_frame;
389 db_backtrace(curthread, NULL, frame, callpc, 0, -1);
390 }
391
392 int
393 db_trace_thread(struct thread *thr, int count)
394 {
395 struct pcb *ctx;
396 struct trapframe *tf;
397
398 ctx = kdb_thr_ctx(thr);
399 tf = thr == kdb_thread ? kdb_frame : NULL;
400 return (db_backtrace(thr, tf, (struct amd64_frame *)ctx->pcb_rbp,
401 ctx->pcb_rip, ctx->pcb_rsp, count));
402 }
403
404 int
405 amd64_set_watch(watchnum, watchaddr, size, access, d)
406 int watchnum;
407 unsigned long watchaddr;
408 int size;
409 int access;
410 struct dbreg *d;
411 {
412 int i, len;
413
414 if (watchnum == -1) {
415 for (i = 0; i < 4; i++)
416 if (!DBREG_DR7_ENABLED(d->dr[7], i))
417 break;
418 if (i < 4)
419 watchnum = i;
420 else
421 return (-1);
422 }
423
424 switch (access) {
425 case DBREG_DR7_EXEC:
426 size = 1; /* size must be 1 for an execution breakpoint */
427 /* fall through */
428 case DBREG_DR7_WRONLY:
429 case DBREG_DR7_RDWR:
430 break;
431 default:
432 return (-1);
433 }
434
435 /*
436 * we can watch a 1, 2, 4, or 8 byte sized location
437 */
438 switch (size) {
439 case 1:
440 len = DBREG_DR7_LEN_1;
441 break;
442 case 2:
443 len = DBREG_DR7_LEN_2;
444 break;
445 case 4:
446 len = DBREG_DR7_LEN_4;
447 break;
448 case 8:
449 len = DBREG_DR7_LEN_8;
450 break;
451 default:
452 return (-1);
453 }
454
455 /* clear the bits we are about to affect */
456 d->dr[7] &= ~DBREG_DR7_MASK(watchnum);
457
458 /* set drN register to the address, N=watchnum */
459 DBREG_DRX(d, watchnum) = watchaddr;
460
461 /* enable the watchpoint */
462 d->dr[7] |= DBREG_DR7_SET(watchnum, len, access,
463 DBREG_DR7_GLOBAL_ENABLE);
464
465 return (watchnum);
466 }
467
468
469 int
470 amd64_clr_watch(watchnum, d)
471 int watchnum;
472 struct dbreg *d;
473 {
474
475 if (watchnum < 0 || watchnum >= 4)
476 return (-1);
477
478 d->dr[7] &= ~DBREG_DR7_MASK(watchnum);
479 DBREG_DRX(d, watchnum) = 0;
480
481 return (0);
482 }
483
484
485 int
486 db_md_set_watchpoint(addr, size)
487 db_expr_t addr;
488 db_expr_t size;
489 {
490 struct dbreg *d;
491 struct pcpu *pc;
492 int avail, c, cpu, i, wsize;
493
494 d = (struct dbreg *)PCPU_PTR(dbreg);
495 cpu = PCPU_GET(cpuid);
496 fill_dbregs(NULL, d);
497
498 avail = 0;
499 for (i = 0; i < 4; i++) {
500 if (!DBREG_DR7_ENABLED(d->dr[7], i))
501 avail++;
502 }
503
504 if (avail * 8 < size)
505 return (-1);
506
507 for (i = 0; i < 4 && size > 0; i++) {
508 if (!DBREG_DR7_ENABLED(d->dr[7], i)) {
509 if (size >= 8 || (avail == 1 && size > 4))
510 wsize = 8;
511 else if (size > 2)
512 wsize = 4;
513 else
514 wsize = size;
515 amd64_set_watch(i, addr, wsize, DBREG_DR7_WRONLY, d);
516 addr += wsize;
517 size -= wsize;
518 avail--;
519 }
520 }
521
522 set_dbregs(NULL, d);
523 CPU_FOREACH(c) {
524 if (c == cpu)
525 continue;
526 pc = pcpu_find(c);
527 memcpy(pc->pc_dbreg, d, sizeof(*d));
528 pc->pc_dbreg_cmd = PC_DBREG_CMD_LOAD;
529 }
530
531 return (0);
532 }
533
534 int
535 db_md_clr_watchpoint(addr, size)
536 db_expr_t addr;
537 db_expr_t size;
538 {
539 struct dbreg *d;
540 struct pcpu *pc;
541 int i, c, cpu;
542
543 d = (struct dbreg *)PCPU_PTR(dbreg);
544 cpu = PCPU_GET(cpuid);
545 fill_dbregs(NULL, d);
546
547 for (i = 0; i < 4; i++) {
548 if (DBREG_DR7_ENABLED(d->dr[7], i)) {
549 if (DBREG_DRX((d), i) >= addr &&
550 DBREG_DRX((d), i) < addr + size)
551 amd64_clr_watch(i, d);
552
553 }
554 }
555
556 set_dbregs(NULL, d);
557 CPU_FOREACH(c) {
558 if (c == cpu)
559 continue;
560 pc = pcpu_find(c);
561 memcpy(pc->pc_dbreg, d, sizeof(*d));
562 pc->pc_dbreg_cmd = PC_DBREG_CMD_LOAD;
563 }
564
565 return (0);
566 }
567
568
569 static const char *
570 watchtype_str(type)
571 int type;
572 {
573 switch (type) {
574 case DBREG_DR7_EXEC : return "execute"; break;
575 case DBREG_DR7_RDWR : return "read/write"; break;
576 case DBREG_DR7_WRONLY : return "write"; break;
577 default : return "invalid"; break;
578 }
579 }
580
581
582 void
583 db_md_list_watchpoints()
584 {
585 struct dbreg d;
586 int i, len, type;
587
588 fill_dbregs(NULL, &d);
589
590 db_printf("\nhardware watchpoints:\n");
591 db_printf(" watch status type len address\n");
592 db_printf(" ----- -------- ---------- --- ------------------\n");
593 for (i = 0; i < 4; i++) {
594 if (DBREG_DR7_ENABLED(d.dr[7], i)) {
595 type = DBREG_DR7_ACCESS(d.dr[7], i);
596 len = DBREG_DR7_LEN(d.dr[7], i);
597 if (len == DBREG_DR7_LEN_8)
598 len = 8;
599 else
600 len++;
601 db_printf(" %-5d %-8s %10s %3d ",
602 i, "enabled", watchtype_str(type), len);
603 db_printsym((db_addr_t)DBREG_DRX((&d), i), DB_STGY_ANY);
604 db_printf("\n");
605 } else {
606 db_printf(" %-5d disabled\n", i);
607 }
608 }
609
610 db_printf("\ndebug register values:\n");
611 for (i = 0; i < 8; i++) {
612 db_printf(" dr%d 0x%016lx\n", i, DBREG_DRX((&d), i));
613 }
614 db_printf("\n");
615 }
616
617 void
618 amd64_db_resume_dbreg(void)
619 {
620 struct dbreg *d;
621
622 switch (PCPU_GET(dbreg_cmd)) {
623 case PC_DBREG_CMD_LOAD:
624 d = (struct dbreg *)PCPU_PTR(dbreg);
625 set_dbregs(NULL, d);
626 PCPU_SET(dbreg_cmd, PC_DBREG_CMD_NONE);
627 break;
628 }
629 }
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