2 * Mach Operating System
3 * Copyright (c) 1991,1990 Carnegie Mellon University
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.
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.
16 * Carnegie Mellon requests users of this software to return to
18 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
19 * School of Computer Science
20 * Carnegie Mellon University
21 * Pittsburgh PA 15213-3890
23 * any improvements or extensions that they make and grant Carnegie the
24 * rights to redistribute these changes.
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
30 #include <sys/param.h>
31 #include <sys/systm.h>
34 #include <sys/sysent.h>
36 #include <machine/cpu.h>
37 #include <machine/frame.h>
38 #include <machine/md_var.h>
39 #include <machine/pcb.h>
40 #include <machine/reg.h>
41 #include <machine/stack.h>
44 #include <vm/vm_param.h>
48 #include <ddb/db_access.h>
49 #include <ddb/db_sym.h>
50 #include <ddb/db_variables.h>
52 static db_varfcn_t db_esp;
53 static db_varfcn_t db_frame;
54 static db_varfcn_t db_frame_seg;
55 static db_varfcn_t db_gs;
56 static db_varfcn_t db_ss;
59 * Machine register set.
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", NULL, db_gs },
68 { "ss", NULL, db_ss },
69 { "eax", DB_OFFSET(tf_eax), db_frame },
70 { "ecx", DB_OFFSET(tf_ecx), db_frame },
71 { "edx", DB_OFFSET(tf_edx), db_frame },
72 { "ebx", DB_OFFSET(tf_ebx), db_frame },
73 { "esp", NULL, db_esp },
74 { "ebp", DB_OFFSET(tf_ebp), db_frame },
75 { "esi", DB_OFFSET(tf_esi), db_frame },
76 { "edi", DB_OFFSET(tf_edi), db_frame },
77 { "eip", DB_OFFSET(tf_eip), db_frame },
78 { "efl", DB_OFFSET(tf_eflags), db_frame },
80 struct db_variable *db_eregs = db_regs + nitems(db_regs);
83 get_esp(struct trapframe *tf)
85 return ((ISPL(tf->tf_cs) || kdb_frame->tf_eflags & PSL_VM) ?
86 tf->tf_esp : (intptr_t)&tf->tf_esp);
90 db_frame(struct db_variable *vp, db_expr_t *valuep, int op)
94 if (kdb_frame == NULL)
97 reg = (int *)((uintptr_t)kdb_frame + (db_expr_t)vp->valuep);
106 db_frame_seg(struct db_variable *vp, db_expr_t *valuep, int op)
108 struct trapframe_vm86 *tfp;
112 if (kdb_frame == NULL)
115 off = (intptr_t)vp->valuep;
116 if (kdb_frame->tf_eflags & PSL_VM) {
117 tfp = (void *)kdb_frame;
118 switch ((intptr_t)vp->valuep) {
119 case (intptr_t)DB_OFFSET(tf_cs):
120 reg = (uint16_t *)&tfp->tf_cs;
122 case (intptr_t)DB_OFFSET(tf_ds):
123 reg = (uint16_t *)&tfp->tf_vm86_ds;
125 case (intptr_t)DB_OFFSET(tf_es):
126 reg = (uint16_t *)&tfp->tf_vm86_es;
128 case (intptr_t)DB_OFFSET(tf_fs):
129 reg = (uint16_t *)&tfp->tf_vm86_fs;
133 reg = (uint16_t *)((uintptr_t)kdb_frame + off);
134 if (op == DB_VAR_GET)
142 db_esp(struct db_variable *vp, db_expr_t *valuep, int op)
145 if (kdb_frame == NULL)
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;
156 db_gs(struct db_variable *vp, db_expr_t *valuep, int op)
158 struct trapframe_vm86 *tfp;
160 if (kdb_frame != NULL && kdb_frame->tf_eflags & PSL_VM) {
161 tfp = (void *)kdb_frame;
162 if (op == DB_VAR_GET)
163 *valuep = tfp->tf_vm86_gs;
165 tfp->tf_vm86_gs = *valuep;
168 if (op == DB_VAR_GET)
176 db_ss(struct db_variable *vp, db_expr_t *valuep, int op)
179 if (kdb_frame == NULL)
182 if (op == DB_VAR_GET)
183 *valuep = (ISPL(kdb_frame->tf_cs) ||
184 kdb_frame->tf_eflags & PSL_VM) ? kdb_frame->tf_ss : rss();
185 else if (ISPL(kdb_frame->tf_cs) || kdb_frame->tf_eflags & PSL_VM)
186 kdb_frame->tf_ss = *valuep;
194 #define DOUBLE_FAULT 4
195 #define TRAP_INTERRUPT 5
196 #define TRAP_TIMERINT 6
198 static void db_nextframe(struct i386_frame **, db_addr_t *, struct thread *);
199 static int db_numargs(struct i386_frame *);
200 static void db_print_stack_entry(const char *, int, char **, int *, db_addr_t,
202 static void decode_syscall(int, struct thread *);
204 static const char * watchtype_str(int type);
205 int i386_set_watch(int watchnum, unsigned int watchaddr, int size, int access,
207 int i386_clr_watch(int watchnum, struct dbreg *d);
210 * Figure out how many arguments were passed into the frame at "fp".
214 struct i386_frame *fp;
220 argp = (char *)db_get_value((int)&fp->f_retaddr, 4, FALSE);
222 * XXX etext is wrong for LKMs. We should attempt to interpret
223 * the instruction at the return address in all cases. This
224 * may require better fault handling.
226 if (argp < btext || argp >= etext) {
230 inst = db_get_value((int)argp, 4, FALSE);
231 if ((inst & 0xff) == 0x59) /* popl %ecx */
233 else if ((inst & 0xffff) == 0xc483) /* addl $Ibs, %esp */
234 args = ((inst >> 16) & 0xff) / 4;
235 else if ((inst & 0xf8ff) == 0xc089) { /* movl %eax, %Reg */
245 db_print_stack_entry(name, narg, argnp, argp, callpc, frame)
253 int n = narg >= 0 ? narg : 5;
255 db_printf("%s(", name);
258 db_printf("%s=", *argnp++);
259 db_printf("%r", db_get_value((int)argp, 4, FALSE));
267 db_printsym(callpc, DB_STGY_PROC);
269 db_printf("/frame 0x%r", (register_t)frame);
274 decode_syscall(int number, struct thread *td)
282 db_printf(" (%d", number);
283 p = (td != NULL) ? td->td_proc : NULL;
284 if (p != NULL && 0 <= number && number < p->p_sysent->sv_size) {
285 f = p->p_sysent->sv_table[number].sy_call;
286 sym = db_search_symbol((db_addr_t)f, DB_STGY_ANY, &diff);
287 if (sym != DB_SYM_NULL && diff == 0) {
288 db_symbol_values(sym, &symname, NULL);
289 db_printf(", %s, %s", p->p_sysent->sv_name, symname);
296 * Figure out the next frame up in the call stack.
299 db_nextframe(struct i386_frame **fp, db_addr_t *ip, struct thread *td)
301 struct trapframe *tf;
308 eip = db_get_value((int) &(*fp)->f_retaddr, 4, FALSE);
309 ebp = db_get_value((int) &(*fp)->f_frame, 4, FALSE);
312 * Figure out frame type. We look at the address just before
313 * the saved instruction pointer as the saved EIP is after the
314 * call function, and if the function being called is marked as
315 * dead (such as panic() at the end of dblfault_handler()), then
316 * the instruction at the saved EIP will be part of a different
317 * function (syscall() in this example) rather than the one that
318 * actually made the call.
321 sym = db_search_symbol(eip - 1, DB_STGY_ANY, &offset);
322 db_symbol_values(sym, &name, NULL);
324 if (strcmp(name, "calltrap") == 0 ||
325 strcmp(name, "fork_trampoline") == 0)
327 else if (strncmp(name, "Xatpic_intr", 11) == 0 ||
328 strncmp(name, "Xapic_isr", 9) == 0)
329 frame_type = INTERRUPT;
330 else if (strcmp(name, "Xlcall_syscall") == 0 ||
331 strcmp(name, "Xint0x80_syscall") == 0)
332 frame_type = SYSCALL;
333 else if (strcmp(name, "dblfault_handler") == 0)
334 frame_type = DOUBLE_FAULT;
335 /* XXX: These are interrupts with trap frames. */
336 else if (strcmp(name, "Xtimerint") == 0)
337 frame_type = TRAP_TIMERINT;
338 else if (strcmp(name, "Xcpustop") == 0 ||
339 strcmp(name, "Xrendezvous") == 0 ||
340 strcmp(name, "Xipi_intr_bitmap_handler") == 0)
341 frame_type = TRAP_INTERRUPT;
345 * Normal frames need no special processing.
347 if (frame_type == NORMAL) {
348 *ip = (db_addr_t) eip;
349 *fp = (struct i386_frame *) ebp;
353 db_print_stack_entry(name, 0, 0, 0, eip, &(*fp)->f_frame);
356 * For a double fault, we have to snag the values from the
357 * previous TSS since a double fault uses a task gate to
358 * switch to a known good state.
360 if (frame_type == DOUBLE_FAULT) {
361 esp = PCPU_GET(common_tss.tss_esp);
362 eip = PCPU_GET(common_tss.tss_eip);
363 ebp = PCPU_GET(common_tss.tss_ebp);
365 "--- trap 0x17, eip = %#r, esp = %#r, ebp = %#r ---\n",
367 *ip = (db_addr_t) eip;
368 *fp = (struct i386_frame *) ebp;
373 * Point to base of trapframe which is just above the
376 if (frame_type == INTERRUPT)
377 tf = (struct trapframe *)((int)*fp + 16);
378 else if (frame_type == TRAP_INTERRUPT)
379 tf = (struct trapframe *)((int)*fp + 8);
381 tf = (struct trapframe *)((int)*fp + 12);
383 if (INKERNEL((int) tf)) {
387 switch (frame_type) {
389 db_printf("--- trap %#r", tf->tf_trapno);
392 db_printf("--- syscall");
393 decode_syscall(tf->tf_eax, td);
398 db_printf("--- interrupt");
401 panic("The moon has moved again.");
403 db_printf(", eip = %#r, esp = %#r, ebp = %#r ---\n", eip,
407 *ip = (db_addr_t) eip;
408 *fp = (struct i386_frame *) ebp;
412 db_backtrace(struct thread *td, struct trapframe *tf, struct i386_frame *frame,
413 db_addr_t pc, register_t sp, int count)
415 struct i386_frame *actframe;
417 char *argnames[MAXNARG], **argnp = NULL;
426 * If an indirect call via an invalid pointer caused a trap,
427 * %pc contains the invalid address while the return address
428 * of the unlucky caller has been saved by CPU on the stack
429 * just before the trap frame. In this case, try to recover
430 * the caller's address so that the first frame is assigned
431 * to the right spot in the right function, for that is where
432 * the failure actually happened.
434 * This trick depends on the fault address stashed in tf_err
435 * by trap_fatal() before entering KDB.
437 if (kdb_frame && pc == kdb_frame->tf_err) {
439 * Find where the trap frame actually ends.
440 * It won't contain tf_esp or tf_ss unless crossing rings.
442 if (ISPL(kdb_frame->tf_cs))
443 instr = (int)(kdb_frame + 1);
445 instr = (int)&kdb_frame->tf_esp;
446 pc = db_get_value(instr, 4, FALSE);
453 while (count-- && !db_pager_quit) {
454 sym = db_search_symbol(pc, DB_STGY_ANY, &offset);
455 db_symbol_values(sym, &name, NULL);
458 * Attempt to determine a (possibly fake) frame that gives
459 * the caller's pc. It may differ from `frame' if the
460 * current function never sets up a standard frame or hasn't
461 * set one up yet or has just discarded one. The last two
462 * cases can be guessed fairly reliably for code generated
463 * by gcc. The first case is too much trouble to handle in
464 * general because the amount of junk on the stack depends
465 * on the pc (the special handling of "calltrap", etc. in
466 * db_nextframe() works because the `next' pc is special).
471 if (sym == C_DB_SYM_NULL && sp != 0) {
473 * If a symbol couldn't be found, we've probably
474 * jumped to a bogus location, so try and use
475 * the return address to find our caller.
477 db_print_stack_entry(name, 0, 0, 0, pc,
479 pc = db_get_value(sp, 4, FALSE);
480 if (db_search_symbol(pc, DB_STGY_PROC,
481 &offset) == C_DB_SYM_NULL)
484 } else if (tf != NULL) {
485 instr = db_get_value(pc, 4, FALSE);
486 if ((instr & 0xffffff) == 0x00e58955) {
487 /* pushl %ebp; movl %esp, %ebp */
488 actframe = (void *)(get_esp(tf) - 4);
489 } else if ((instr & 0xffff) == 0x0000e589) {
490 /* movl %esp, %ebp */
491 actframe = (void *)get_esp(tf);
492 if (tf->tf_ebp == 0) {
493 /* Fake frame better. */
496 } else if ((instr & 0xff) == 0x000000c3) {
498 actframe = (void *)(get_esp(tf) - 4);
499 } else if (offset == 0) {
500 /* Probably an assembler symbol. */
501 actframe = (void *)(get_esp(tf) - 4);
503 } else if (strcmp(name, "fork_trampoline") == 0) {
505 * Don't try to walk back on a stack for a
506 * process that hasn't actually been run yet.
508 db_print_stack_entry(name, 0, 0, 0, pc,
514 argp = &actframe->f_arg0;
516 if (sym != NULL && db_sym_numargs(sym, &narg, argnames)) {
519 narg = db_numargs(frame);
522 db_print_stack_entry(name, narg, argnp, argp, pc, actframe);
524 if (actframe != frame) {
525 /* `frame' belongs to caller. */
527 db_get_value((int)&actframe->f_retaddr, 4, FALSE);
531 db_nextframe(&frame, &pc, td);
533 if (INKERNEL((int)pc) && !INKERNEL((int) frame)) {
534 sym = db_search_symbol(pc, DB_STGY_ANY, &offset);
535 db_symbol_values(sym, &name, NULL);
536 db_print_stack_entry(name, 0, 0, 0, pc, frame);
539 if (!INKERNEL((int) frame)) {
550 struct i386_frame *frame;
554 __asm __volatile("movl %%ebp,%0" : "=r" (ebp));
555 frame = (struct i386_frame *)ebp;
556 callpc = (db_addr_t)db_get_value((int)&frame->f_retaddr, 4, FALSE);
557 frame = frame->f_frame;
558 db_backtrace(curthread, NULL, frame, callpc, 0, -1);
562 db_trace_thread(struct thread *thr, int count)
565 struct trapframe *tf;
567 ctx = kdb_thr_ctx(thr);
568 tf = thr == kdb_thread ? kdb_frame : NULL;
569 return (db_backtrace(thr, tf, (struct i386_frame *)ctx->pcb_ebp,
570 ctx->pcb_eip, ctx->pcb_esp, count));
574 i386_set_watch(watchnum, watchaddr, size, access, d)
576 unsigned int watchaddr;
583 if (watchnum == -1) {
584 for (i = 0; i < 4; i++)
585 if (!DBREG_DR7_ENABLED(d->dr[7], i))
595 size = 1; /* size must be 1 for an execution breakpoint */
597 case DBREG_DR7_WRONLY:
605 * we can watch a 1, 2, or 4 byte sized location
609 len = DBREG_DR7_LEN_1;
612 len = DBREG_DR7_LEN_2;
615 len = DBREG_DR7_LEN_4;
621 /* clear the bits we are about to affect */
622 d->dr[7] &= ~DBREG_DR7_MASK(watchnum);
624 /* set drN register to the address, N=watchnum */
625 DBREG_DRX(d, watchnum) = watchaddr;
627 /* enable the watchpoint */
628 d->dr[7] |= DBREG_DR7_SET(watchnum, len, access,
629 DBREG_DR7_GLOBAL_ENABLE);
636 i386_clr_watch(watchnum, d)
641 if (watchnum < 0 || watchnum >= 4)
644 d->dr[7] &= ~DBREG_DR7_MASK(watchnum);
645 DBREG_DRX(d, watchnum) = 0;
652 db_md_set_watchpoint(addr, size)
659 fill_dbregs(NULL, &d);
662 for(i = 0; i < 4; i++) {
663 if (!DBREG_DR7_ENABLED(d.dr[7], i))
667 if (avail * 4 < size)
670 for (i = 0; i < 4 && (size > 0); i++) {
671 if (!DBREG_DR7_ENABLED(d.dr[7], i)) {
676 i386_set_watch(i, addr, wsize,
677 DBREG_DR7_WRONLY, &d);
683 set_dbregs(NULL, &d);
690 db_md_clr_watchpoint(addr, size)
697 fill_dbregs(NULL, &d);
699 for(i = 0; i < 4; i++) {
700 if (DBREG_DR7_ENABLED(d.dr[7], i)) {
701 if ((DBREG_DRX((&d), i) >= addr) &&
702 (DBREG_DRX((&d), i) < addr+size))
703 i386_clr_watch(i, &d);
708 set_dbregs(NULL, &d);
719 case DBREG_DR7_EXEC : return "execute"; break;
720 case DBREG_DR7_RDWR : return "read/write"; break;
721 case DBREG_DR7_WRONLY : return "write"; break;
722 default : return "invalid"; break;
728 db_md_list_watchpoints()
733 fill_dbregs(NULL, &d);
735 db_printf("\nhardware watchpoints:\n");
736 db_printf(" watch status type len address\n");
737 db_printf(" ----- -------- ---------- --- ----------\n");
738 for (i = 0; i < 4; i++) {
739 if (DBREG_DR7_ENABLED(d.dr[7], i)) {
740 type = DBREG_DR7_ACCESS(d.dr[7], i);
741 len = DBREG_DR7_LEN(d.dr[7], i);
742 db_printf(" %-5d %-8s %10s %3d ",
743 i, "enabled", watchtype_str(type), len + 1);
744 db_printsym((db_addr_t)DBREG_DRX((&d), i), DB_STGY_ANY);
747 db_printf(" %-5d disabled\n", i);
751 db_printf("\ndebug register values:\n");
752 for (i = 0; i < 8; i++) {
753 db_printf(" dr%d 0x%08x\n", i, DBREG_DRX((&d), i));