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 (TF_HAS_STACKREGS(tf) ? tf->tf_esp : (intptr_t)&tf->tf_esp);
89 db_frame(struct db_variable *vp, db_expr_t *valuep, int op)
93 if (kdb_frame == NULL)
96 reg = (int *)((uintptr_t)kdb_frame + (db_expr_t)vp->valuep);
105 db_frame_seg(struct db_variable *vp, db_expr_t *valuep, int op)
107 struct trapframe_vm86 *tfp;
111 if (kdb_frame == NULL)
114 off = (intptr_t)vp->valuep;
115 if (kdb_frame->tf_eflags & PSL_VM) {
116 tfp = (void *)kdb_frame;
117 switch ((intptr_t)vp->valuep) {
118 case (intptr_t)DB_OFFSET(tf_cs):
119 reg = (uint16_t *)&tfp->tf_cs;
121 case (intptr_t)DB_OFFSET(tf_ds):
122 reg = (uint16_t *)&tfp->tf_vm86_ds;
124 case (intptr_t)DB_OFFSET(tf_es):
125 reg = (uint16_t *)&tfp->tf_vm86_es;
127 case (intptr_t)DB_OFFSET(tf_fs):
128 reg = (uint16_t *)&tfp->tf_vm86_fs;
132 reg = (uint16_t *)((uintptr_t)kdb_frame + off);
133 if (op == DB_VAR_GET)
141 db_esp(struct db_variable *vp, db_expr_t *valuep, int op)
144 if (kdb_frame == NULL)
147 if (op == DB_VAR_GET)
148 *valuep = get_esp(kdb_frame);
149 else if (TF_HAS_STACKREGS(kdb_frame))
150 kdb_frame->tf_esp = *valuep;
155 db_gs(struct db_variable *vp, db_expr_t *valuep, int op)
157 struct trapframe_vm86 *tfp;
159 if (kdb_frame != NULL && kdb_frame->tf_eflags & PSL_VM) {
160 tfp = (void *)kdb_frame;
161 if (op == DB_VAR_GET)
162 *valuep = tfp->tf_vm86_gs;
164 tfp->tf_vm86_gs = *valuep;
167 if (op == DB_VAR_GET)
175 db_ss(struct db_variable *vp, db_expr_t *valuep, int op)
178 if (kdb_frame == NULL)
181 if (op == DB_VAR_GET)
182 *valuep = TF_HAS_STACKREGS(kdb_frame) ? kdb_frame->tf_ss :
184 else if (TF_HAS_STACKREGS(kdb_frame))
185 kdb_frame->tf_ss = *valuep;
193 #define DOUBLE_FAULT 4
194 #define TRAP_INTERRUPT 5
195 #define TRAP_TIMERINT 6
197 static void db_nextframe(struct i386_frame **, db_addr_t *, struct thread *);
198 static int db_numargs(struct i386_frame *);
199 static void db_print_stack_entry(const char *, int, char **, int *, db_addr_t,
201 static void decode_syscall(int, struct thread *);
203 static const char * watchtype_str(int type);
204 int i386_set_watch(int watchnum, unsigned int watchaddr, int size, int access,
206 int i386_clr_watch(int watchnum, struct dbreg *d);
209 * Figure out how many arguments were passed into the frame at "fp".
213 struct i386_frame *fp;
219 argp = (char *)db_get_value((int)&fp->f_retaddr, 4, FALSE);
221 * XXX etext is wrong for LKMs. We should attempt to interpret
222 * the instruction at the return address in all cases. This
223 * may require better fault handling.
225 if (argp < btext || argp >= etext) {
229 inst = db_get_value((int)argp, 4, FALSE);
230 if ((inst & 0xff) == 0x59) /* popl %ecx */
232 else if ((inst & 0xffff) == 0xc483) /* addl $Ibs, %esp */
233 args = ((inst >> 16) & 0xff) / 4;
234 else if ((inst & 0xf8ff) == 0xc089) { /* movl %eax, %Reg */
244 db_print_stack_entry(name, narg, argnp, argp, callpc, frame)
252 int n = narg >= 0 ? narg : 5;
254 db_printf("%s(", name);
257 db_printf("%s=", *argnp++);
258 db_printf("%r", db_get_value((int)argp, 4, FALSE));
266 db_printsym(callpc, DB_STGY_PROC);
268 db_printf("/frame 0x%r", (register_t)frame);
273 decode_syscall(int number, struct thread *td)
281 db_printf(" (%d", number);
282 p = (td != NULL) ? td->td_proc : NULL;
283 if (p != NULL && 0 <= number && number < p->p_sysent->sv_size) {
284 f = p->p_sysent->sv_table[number].sy_call;
285 sym = db_search_symbol((db_addr_t)f, DB_STGY_ANY, &diff);
286 if (sym != DB_SYM_NULL && diff == 0) {
287 db_symbol_values(sym, &symname, NULL);
288 db_printf(", %s, %s", p->p_sysent->sv_name, symname);
295 * Figure out the next frame up in the call stack.
298 db_nextframe(struct i386_frame **fp, db_addr_t *ip, struct thread *td)
300 struct trapframe *tf;
307 eip = db_get_value((int) &(*fp)->f_retaddr, 4, FALSE);
308 ebp = db_get_value((int) &(*fp)->f_frame, 4, FALSE);
311 * Figure out frame type. We look at the address just before
312 * the saved instruction pointer as the saved EIP is after the
313 * call function, and if the function being called is marked as
314 * dead (such as panic() at the end of dblfault_handler()), then
315 * the instruction at the saved EIP will be part of a different
316 * function (syscall() in this example) rather than the one that
317 * actually made the call.
320 sym = db_search_symbol(eip - 1, DB_STGY_ANY, &offset);
321 db_symbol_values(sym, &name, NULL);
323 if (strcmp(name, "calltrap") == 0 ||
324 strcmp(name, "fork_trampoline") == 0)
326 else if (strncmp(name, "Xatpic_intr", 11) == 0 ||
327 strncmp(name, "Xapic_isr", 9) == 0)
328 frame_type = INTERRUPT;
329 else if (strcmp(name, "Xlcall_syscall") == 0 ||
330 strcmp(name, "Xint0x80_syscall") == 0)
331 frame_type = SYSCALL;
332 else if (strcmp(name, "dblfault_handler") == 0)
333 frame_type = DOUBLE_FAULT;
334 /* XXX: These are interrupts with trap frames. */
335 else if (strcmp(name, "Xtimerint") == 0)
336 frame_type = TRAP_TIMERINT;
337 else if (strcmp(name, "Xcpustop") == 0 ||
338 strcmp(name, "Xrendezvous") == 0 ||
339 strcmp(name, "Xipi_intr_bitmap_handler") == 0)
340 frame_type = TRAP_INTERRUPT;
344 * Normal frames need no special processing.
346 if (frame_type == NORMAL) {
347 *ip = (db_addr_t) eip;
348 *fp = (struct i386_frame *) ebp;
352 db_print_stack_entry(name, 0, 0, 0, eip, &(*fp)->f_frame);
355 * For a double fault, we have to snag the values from the
356 * previous TSS since a double fault uses a task gate to
357 * switch to a known good state.
359 if (frame_type == DOUBLE_FAULT) {
360 esp = PCPU_GET(common_tss.tss_esp);
361 eip = PCPU_GET(common_tss.tss_eip);
362 ebp = PCPU_GET(common_tss.tss_ebp);
364 "--- trap 0x17, eip = %#r, esp = %#r, ebp = %#r ---\n",
366 *ip = (db_addr_t) eip;
367 *fp = (struct i386_frame *) ebp;
372 * Point to base of trapframe which is just above the
375 if (frame_type == INTERRUPT)
376 tf = (struct trapframe *)((int)*fp + 16);
377 else if (frame_type == TRAP_INTERRUPT)
378 tf = (struct trapframe *)((int)*fp + 8);
380 tf = (struct trapframe *)((int)*fp + 12);
382 if (INKERNEL((int) tf)) {
386 switch (frame_type) {
388 db_printf("--- trap %#r", tf->tf_trapno);
391 db_printf("--- syscall");
392 decode_syscall(tf->tf_eax, td);
397 db_printf("--- interrupt");
400 panic("The moon has moved again.");
402 db_printf(", eip = %#r, esp = %#r, ebp = %#r ---\n", eip,
406 *ip = (db_addr_t) eip;
407 *fp = (struct i386_frame *) ebp;
411 db_backtrace(struct thread *td, struct trapframe *tf, struct i386_frame *frame,
412 db_addr_t pc, register_t sp, int count)
414 struct i386_frame *actframe;
416 char *argnames[MAXNARG], **argnp = NULL;
425 * If an indirect call via an invalid pointer caused a trap,
426 * %pc contains the invalid address while the return address
427 * of the unlucky caller has been saved by CPU on the stack
428 * just before the trap frame. In this case, try to recover
429 * the caller's address so that the first frame is assigned
430 * to the right spot in the right function, for that is where
431 * the failure actually happened.
433 * This trick depends on the fault address stashed in tf_err
434 * by trap_fatal() before entering KDB.
436 if (kdb_frame && pc == kdb_frame->tf_err) {
438 * Find where the trap frame actually ends.
439 * It won't contain tf_esp or tf_ss unless crossing rings.
441 if (TF_HAS_STACKREGS(kdb_frame))
442 instr = (int)(kdb_frame + 1);
444 instr = (int)&kdb_frame->tf_esp;
445 pc = db_get_value(instr, 4, FALSE);
452 while (count-- && !db_pager_quit) {
453 sym = db_search_symbol(pc, DB_STGY_ANY, &offset);
454 db_symbol_values(sym, &name, NULL);
457 * Attempt to determine a (possibly fake) frame that gives
458 * the caller's pc. It may differ from `frame' if the
459 * current function never sets up a standard frame or hasn't
460 * set one up yet or has just discarded one. The last two
461 * cases can be guessed fairly reliably for code generated
462 * by gcc. The first case is too much trouble to handle in
463 * general because the amount of junk on the stack depends
464 * on the pc (the special handling of "calltrap", etc. in
465 * db_nextframe() works because the `next' pc is special).
470 if (sym == C_DB_SYM_NULL && sp != 0) {
472 * If a symbol couldn't be found, we've probably
473 * jumped to a bogus location, so try and use
474 * the return address to find our caller.
476 db_print_stack_entry(name, 0, 0, 0, pc,
478 pc = db_get_value(sp, 4, FALSE);
479 if (db_search_symbol(pc, DB_STGY_PROC,
480 &offset) == C_DB_SYM_NULL)
483 } else if (tf != NULL) {
484 instr = db_get_value(pc, 4, FALSE);
485 if ((instr & 0xffffff) == 0x00e58955) {
486 /* pushl %ebp; movl %esp, %ebp */
487 actframe = (void *)(get_esp(tf) - 4);
488 } else if ((instr & 0xffff) == 0x0000e589) {
489 /* movl %esp, %ebp */
490 actframe = (void *)get_esp(tf);
491 if (tf->tf_ebp == 0) {
492 /* Fake frame better. */
495 } else if ((instr & 0xff) == 0x000000c3) {
497 actframe = (void *)(get_esp(tf) - 4);
498 } else if (offset == 0) {
499 /* Probably an assembler symbol. */
500 actframe = (void *)(get_esp(tf) - 4);
502 } else if (strcmp(name, "fork_trampoline") == 0) {
504 * Don't try to walk back on a stack for a
505 * process that hasn't actually been run yet.
507 db_print_stack_entry(name, 0, 0, 0, pc,
513 argp = &actframe->f_arg0;
515 if (sym != NULL && db_sym_numargs(sym, &narg, argnames)) {
518 narg = db_numargs(frame);
521 db_print_stack_entry(name, narg, argnp, argp, pc, actframe);
523 if (actframe != frame) {
524 /* `frame' belongs to caller. */
526 db_get_value((int)&actframe->f_retaddr, 4, FALSE);
530 db_nextframe(&frame, &pc, td);
532 if (INKERNEL((int)pc) && !INKERNEL((int) frame)) {
533 sym = db_search_symbol(pc, DB_STGY_ANY, &offset);
534 db_symbol_values(sym, &name, NULL);
535 db_print_stack_entry(name, 0, 0, 0, pc, frame);
538 if (!INKERNEL((int) frame)) {
549 struct i386_frame *frame;
553 __asm __volatile("movl %%ebp,%0" : "=r" (ebp));
554 frame = (struct i386_frame *)ebp;
555 callpc = (db_addr_t)db_get_value((int)&frame->f_retaddr, 4, FALSE);
556 frame = frame->f_frame;
557 db_backtrace(curthread, NULL, frame, callpc, 0, -1);
561 db_trace_thread(struct thread *thr, int count)
564 struct trapframe *tf;
566 ctx = kdb_thr_ctx(thr);
567 tf = thr == kdb_thread ? kdb_frame : NULL;
568 return (db_backtrace(thr, tf, (struct i386_frame *)ctx->pcb_ebp,
569 ctx->pcb_eip, ctx->pcb_esp, count));
573 i386_set_watch(watchnum, watchaddr, size, access, d)
575 unsigned int watchaddr;
582 if (watchnum == -1) {
583 for (i = 0; i < 4; i++)
584 if (!DBREG_DR7_ENABLED(d->dr[7], i))
594 size = 1; /* size must be 1 for an execution breakpoint */
596 case DBREG_DR7_WRONLY:
604 * we can watch a 1, 2, or 4 byte sized location
608 len = DBREG_DR7_LEN_1;
611 len = DBREG_DR7_LEN_2;
614 len = DBREG_DR7_LEN_4;
620 /* clear the bits we are about to affect */
621 d->dr[7] &= ~DBREG_DR7_MASK(watchnum);
623 /* set drN register to the address, N=watchnum */
624 DBREG_DRX(d, watchnum) = watchaddr;
626 /* enable the watchpoint */
627 d->dr[7] |= DBREG_DR7_SET(watchnum, len, access,
628 DBREG_DR7_GLOBAL_ENABLE);
635 i386_clr_watch(watchnum, d)
640 if (watchnum < 0 || watchnum >= 4)
643 d->dr[7] &= ~DBREG_DR7_MASK(watchnum);
644 DBREG_DRX(d, watchnum) = 0;
651 db_md_set_watchpoint(addr, size)
658 fill_dbregs(NULL, &d);
661 for(i = 0; i < 4; i++) {
662 if (!DBREG_DR7_ENABLED(d.dr[7], i))
666 if (avail * 4 < size)
669 for (i = 0; i < 4 && (size > 0); i++) {
670 if (!DBREG_DR7_ENABLED(d.dr[7], i)) {
675 i386_set_watch(i, addr, wsize,
676 DBREG_DR7_WRONLY, &d);
682 set_dbregs(NULL, &d);
689 db_md_clr_watchpoint(addr, size)
696 fill_dbregs(NULL, &d);
698 for(i = 0; i < 4; i++) {
699 if (DBREG_DR7_ENABLED(d.dr[7], i)) {
700 if ((DBREG_DRX((&d), i) >= addr) &&
701 (DBREG_DRX((&d), i) < addr+size))
702 i386_clr_watch(i, &d);
707 set_dbregs(NULL, &d);
718 case DBREG_DR7_EXEC : return "execute"; break;
719 case DBREG_DR7_RDWR : return "read/write"; break;
720 case DBREG_DR7_WRONLY : return "write"; break;
721 default : return "invalid"; break;
727 db_md_list_watchpoints()
732 fill_dbregs(NULL, &d);
734 db_printf("\nhardware watchpoints:\n");
735 db_printf(" watch status type len address\n");
736 db_printf(" ----- -------- ---------- --- ----------\n");
737 for (i = 0; i < 4; i++) {
738 if (DBREG_DR7_ENABLED(d.dr[7], i)) {
739 type = DBREG_DR7_ACCESS(d.dr[7], i);
740 len = DBREG_DR7_LEN(d.dr[7], i);
741 db_printf(" %-5d %-8s %10s %3d ",
742 i, "enabled", watchtype_str(type), len + 1);
743 db_printsym((db_addr_t)DBREG_DRX((&d), i), DB_STGY_ANY);
746 db_printf(" %-5d disabled\n", i);
750 db_printf("\ndebug register values:\n");
751 for (i = 0; i < 8; i++) {
752 db_printf(" dr%d 0x%08x\n", i, DBREG_DRX((&d), i));