8f0c2a62aa
that the latter can easily determine what the trap type actually is after callers are fixed to encode the type unambigously. ddb currently barely understands breakpoints, and it treats all non-breakpoints as single-step traps. This works OK for stopping after every instruction when single-stepping, but is broken for single-stepping with a count > 1 (especially with a large count). ddb needs to stop on the first non-single-step trap while single- stepping. Otherwise, ddb doesn't even stop the first time for fatal traps and external breakpoints like the one in kdb_enter().
280 lines
6.5 KiB
C
280 lines
6.5 KiB
C
/*-
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* Mach Operating System
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* Copyright (c) 1991,1990 Carnegie Mellon University
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* All Rights Reserved.
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*
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* Permission to use, copy, modify and distribute this software and its
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* documentation is hereby granted, provided that both the copyright
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* notice and this permission notice appear in all copies of the
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* software, derivative works or modified versions, and any portions
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* thereof, and that both notices appear in supporting documentation.
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*
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* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS
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* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
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* ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
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*
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* Carnegie Mellon requests users of this software to return to
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*
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* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
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* School of Computer Science
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* Carnegie Mellon University
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* Pittsburgh PA 15213-3890
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*
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* any improvements or extensions that they make and grant Carnegie the
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* rights to redistribute these changes.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/cons.h>
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#include <sys/linker.h>
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#include <sys/kdb.h>
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#include <sys/kernel.h>
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#include <sys/pcpu.h>
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#include <sys/proc.h>
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#include <sys/reboot.h>
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#include <sys/sysctl.h>
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#include <machine/kdb.h>
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#include <machine/pcb.h>
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#include <machine/setjmp.h>
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#include <ddb/ddb.h>
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#include <ddb/db_command.h>
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#include <ddb/db_sym.h>
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SYSCTL_NODE(_debug, OID_AUTO, ddb, CTLFLAG_RW, 0, "DDB settings");
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static dbbe_init_f db_init;
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static dbbe_trap_f db_trap;
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static dbbe_trace_f db_trace_self_wrapper;
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static dbbe_trace_thread_f db_trace_thread_wrapper;
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KDB_BACKEND(ddb, db_init, db_trace_self_wrapper, db_trace_thread_wrapper,
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db_trap);
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/*
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* Symbols can be loaded by specifying the exact addresses of
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* the symtab and strtab in memory. This is used when loaded from
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* boot loaders different than the native one (like Xen).
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*/
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vm_offset_t ksymtab, kstrtab, ksymtab_size;
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bool
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X_db_line_at_pc(db_symtab_t *symtab, c_db_sym_t sym, char **file, int *line,
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db_expr_t off)
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{
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return (false);
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}
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c_db_sym_t
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X_db_lookup(db_symtab_t *symtab, const char *symbol)
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{
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c_linker_sym_t lsym;
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Elf_Sym *sym;
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if (symtab->private == NULL) {
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return ((c_db_sym_t)((!linker_ddb_lookup(symbol, &lsym))
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? lsym : NULL));
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} else {
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sym = (Elf_Sym *)symtab->start;
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while ((char *)sym < symtab->end) {
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if (sym->st_name != 0 &&
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!strcmp(symtab->private + sym->st_name, symbol))
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return ((c_db_sym_t)sym);
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sym++;
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}
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}
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return (NULL);
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}
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c_db_sym_t
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X_db_search_symbol(db_symtab_t *symtab, db_addr_t off, db_strategy_t strat,
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db_expr_t *diffp)
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{
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c_linker_sym_t lsym;
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Elf_Sym *sym, *match;
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unsigned long diff;
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if (symtab->private == NULL) {
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if (!linker_ddb_search_symbol((caddr_t)off, &lsym, &diff)) {
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*diffp = (db_expr_t)diff;
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return ((c_db_sym_t)lsym);
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}
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return (NULL);
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}
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diff = ~0UL;
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match = NULL;
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for (sym = (Elf_Sym*)symtab->start; (char*)sym < symtab->end; sym++) {
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if (sym->st_name == 0 || sym->st_shndx == SHN_UNDEF)
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continue;
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if (off < sym->st_value)
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continue;
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if (ELF_ST_TYPE(sym->st_info) != STT_OBJECT &&
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ELF_ST_TYPE(sym->st_info) != STT_FUNC &&
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ELF_ST_TYPE(sym->st_info) != STT_NOTYPE)
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continue;
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if ((off - sym->st_value) > diff)
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continue;
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if ((off - sym->st_value) < diff) {
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diff = off - sym->st_value;
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match = sym;
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} else {
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if (match == NULL)
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match = sym;
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else if (ELF_ST_BIND(match->st_info) == STB_LOCAL &&
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ELF_ST_BIND(sym->st_info) != STB_LOCAL)
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match = sym;
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}
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if (diff == 0) {
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if (strat == DB_STGY_PROC &&
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ELF_ST_TYPE(sym->st_info) == STT_FUNC &&
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ELF_ST_BIND(sym->st_info) != STB_LOCAL)
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break;
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if (strat == DB_STGY_ANY &&
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ELF_ST_BIND(sym->st_info) != STB_LOCAL)
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break;
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}
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}
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*diffp = (match == NULL) ? off : diff;
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return ((c_db_sym_t)match);
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}
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bool
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X_db_sym_numargs(db_symtab_t *symtab, c_db_sym_t sym, int *nargp,
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char **argp)
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{
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return (false);
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}
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void
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X_db_symbol_values(db_symtab_t *symtab, c_db_sym_t sym, const char **namep,
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db_expr_t *valp)
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{
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linker_symval_t lval;
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if (symtab->private == NULL) {
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linker_ddb_symbol_values((c_linker_sym_t)sym, &lval);
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if (namep != NULL)
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*namep = (const char*)lval.name;
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if (valp != NULL)
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*valp = (db_expr_t)lval.value;
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} else {
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if (namep != NULL)
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*namep = (const char *)symtab->private +
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((const Elf_Sym *)sym)->st_name;
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if (valp != NULL)
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*valp = (db_expr_t)((const Elf_Sym *)sym)->st_value;
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}
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}
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int
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db_fetch_ksymtab(vm_offset_t ksym_start, vm_offset_t ksym_end)
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{
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Elf_Size strsz;
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if (ksym_end > ksym_start && ksym_start != 0) {
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ksymtab = ksym_start;
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ksymtab_size = *(Elf_Size*)ksymtab;
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ksymtab += sizeof(Elf_Size);
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kstrtab = ksymtab + ksymtab_size;
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strsz = *(Elf_Size*)kstrtab;
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kstrtab += sizeof(Elf_Size);
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if (kstrtab + strsz > ksym_end) {
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/* Sizes doesn't match, unset everything. */
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ksymtab = ksymtab_size = kstrtab = 0;
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}
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}
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if (ksymtab == 0 || ksymtab_size == 0 || kstrtab == 0)
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return (-1);
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return (0);
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}
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static int
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db_init(void)
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{
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db_command_init();
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if (ksymtab != 0 && kstrtab != 0 && ksymtab_size != 0) {
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db_add_symbol_table((char *)ksymtab,
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(char *)(ksymtab + ksymtab_size), "elf", (char *)kstrtab);
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}
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db_add_symbol_table(NULL, NULL, "kld", NULL);
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return (1); /* We're the default debugger. */
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}
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static int
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db_trap(int type, int code)
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{
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jmp_buf jb;
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void *prev_jb;
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bool bkpt, watchpt;
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const char *why;
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/*
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* Don't handle the trap if the console is unavailable (i.e. it
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* is in graphics mode).
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*/
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if (cnunavailable())
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return (0);
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if (db_stop_at_pc(type, code, &bkpt, &watchpt)) {
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if (db_inst_count) {
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db_printf("After %d instructions (%d loads, %d stores),\n",
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db_inst_count, db_load_count, db_store_count);
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}
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prev_jb = kdb_jmpbuf(jb);
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if (setjmp(jb) == 0) {
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db_dot = PC_REGS();
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db_print_thread();
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if (bkpt)
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db_printf("Breakpoint at\t");
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else if (watchpt)
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db_printf("Watchpoint at\t");
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else
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db_printf("Stopped at\t");
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db_print_loc_and_inst(db_dot);
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}
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why = kdb_why;
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db_script_kdbenter(why != KDB_WHY_UNSET ? why : "unknown");
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db_command_loop();
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(void)kdb_jmpbuf(prev_jb);
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}
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db_restart_at_pc(watchpt);
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return (1);
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}
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static void
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db_trace_self_wrapper(void)
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{
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jmp_buf jb;
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void *prev_jb;
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prev_jb = kdb_jmpbuf(jb);
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if (setjmp(jb) == 0)
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db_trace_self();
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(void)kdb_jmpbuf(prev_jb);
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}
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static void
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db_trace_thread_wrapper(struct thread *td)
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{
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jmp_buf jb;
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void *prev_jb;
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prev_jb = kdb_jmpbuf(jb);
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if (setjmp(jb) == 0)
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db_trace_thread(td, -1);
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(void)kdb_jmpbuf(prev_jb);
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}
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