sys/ddb/db_main.c

   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/cons.h>
  33 #include <sys/linker.h>
  34 #include <sys/kdb.h>
  35 #include <sys/kernel.h>
  36 #include <sys/pcpu.h>
  37 #include <sys/proc.h>
  38 #include <sys/reboot.h>
  39 #include <sys/sysctl.h>
  40
  41 #include <machine/kdb.h>
  42 #include <machine/pcb.h>
  43 #include <machine/setjmp.h>
  44
  45 #include <ddb/ddb.h>
  46 #include <ddb/db_command.h>
  47 #include <ddb/db_sym.h>
  48
  49 SYSCTL_NODE(_debug, OID_AUTO, ddb, CTLFLAG_RW, 0, "DDB settings");
  50
  51 static dbbe_init_f db_init;
  52 static dbbe_trap_f db_trap;
  53 static dbbe_trace_f db_trace_self_wrapper;
  54
  55 KDB_BACKEND(ddb, db_init, db_trace_self_wrapper, db_trap);
  56
  57 vm_offset_t ksym_start, ksym_end;
  58
  59 boolean_t
  60 X_db_line_at_pc(db_symtab_t *symtab, c_db_sym_t sym, char **file, int *line,
  61     db_expr_t off)
  62 {
  63         return (FALSE);
  64 }
  65
  66 c_db_sym_t
  67 X_db_lookup(db_symtab_t *symtab, const char *symbol)
  68 {
  69         c_linker_sym_t lsym;
  70         Elf_Sym *sym;
  71
  72         if (symtab->private == NULL) {
  73                 return ((c_db_sym_t)((!linker_ddb_lookup(symbol, &lsym))
  74                         ? lsym : NULL));
  75         } else {
  76                 sym = (Elf_Sym *)symtab->start;
  77                 while ((char *)sym < symtab->end) {
  78                         if (sym->st_name != 0 &&
  79                             !strcmp(symtab->private + sym->st_name, symbol))
  80                                 return ((c_db_sym_t)sym);
  81                         sym++;
  82                 }
  83         }
  84         return (NULL);
  85 }
  86
  87 c_db_sym_t
  88 X_db_search_symbol(db_symtab_t *symtab, db_addr_t off, db_strategy_t strat,
  89     db_expr_t *diffp)
  90 {
  91         c_linker_sym_t lsym;
  92         Elf_Sym *sym, *match;
  93         unsigned long diff;
  94
  95         if (symtab->private == NULL) {
  96                 if (!linker_ddb_search_symbol((caddr_t)off, &lsym, &diff)) {
  97                         *diffp = (db_expr_t)diff;
  98                         return ((c_db_sym_t)lsym);
  99                 }
 100                 return (NULL);
 101         }
 102
 103         diff = ~0UL;
 104         match = NULL;
 105         for (sym = (Elf_Sym*)symtab->start; (char*)sym < symtab->end; sym++) {
 106                 if (sym->st_name == 0)
 107                         continue;
 108                 if (off < sym->st_value)
 109                         continue;
 110                 if (ELF_ST_TYPE(sym->st_info) != STT_OBJECT &&
 111                     ELF_ST_TYPE(sym->st_info) != STT_FUNC &&
 112                     ELF_ST_TYPE(sym->st_info) != STT_NOTYPE)
 113                         continue;
 114                 if ((off - sym->st_value) > diff)
 115                         continue;
 116                 if ((off - sym->st_value) < diff) {
 117                         diff = off - sym->st_value;
 118                         match = sym;
 119                 } else {
 120                         if (match == NULL)
 121                                 match = sym;
 122                         else if (ELF_ST_BIND(match->st_info) == STB_LOCAL &&
 123                             ELF_ST_BIND(sym->st_info) != STB_LOCAL)
 124                                 match = sym;
 125                 }
 126                 if (diff == 0) {
 127                         if (strat == DB_STGY_PROC &&
 128                             ELF_ST_TYPE(sym->st_info) == STT_FUNC &&
 129                             ELF_ST_BIND(sym->st_info) != STB_LOCAL)
 130                                 break;
 131                         if (strat == DB_STGY_ANY &&
 132                             ELF_ST_BIND(sym->st_info) != STB_LOCAL)
 133                                 break;
 134                 }
 135         }
 136
 137         *diffp = (match == NULL) ? off : diff;
 138         return ((c_db_sym_t)match);
 139 }
 140
 141 boolean_t
 142 X_db_sym_numargs(db_symtab_t *symtab, c_db_sym_t sym, int *nargp,
 143     char **argp)
 144 {
 145         return (FALSE);
 146 }
 147
 148 void
 149 X_db_symbol_values(db_symtab_t *symtab, c_db_sym_t sym, const char **namep,
 150     db_expr_t *valp)
 151 {
 152         linker_symval_t lval;
 153
 154         if (symtab->private == NULL) {
 155                 linker_ddb_symbol_values((c_linker_sym_t)sym, &lval);
 156                 if (namep != NULL)
 157                         *namep = (const char*)lval.name;
 158                 if (valp != NULL)
 159                         *valp = (db_expr_t)lval.value;
 160         } else {
 161                 if (namep != NULL)
 162                         *namep = (const char *)symtab->private +
 163                             ((const Elf_Sym *)sym)->st_name;
 164                 if (valp != NULL)
 165                         *valp = (db_expr_t)((const Elf_Sym *)sym)->st_value;
 166         }
 167 }
 168
 169 static int
 170 db_init(void)
 171 {
 172         uintptr_t symtab, strtab;
 173         Elf_Size tabsz, strsz;
 174
 175         db_command_init();
 176         if (ksym_end > ksym_start && ksym_start != 0) {
 177                 symtab = ksym_start;
 178                 tabsz = *((Elf_Size*)symtab);
 179                 symtab += sizeof(Elf_Size);
 180                 strtab = symtab + tabsz;
 181                 strsz = *((Elf_Size*)strtab);
 182                 strtab += sizeof(Elf_Size);
 183                 if (strtab + strsz <= ksym_end) {
 184                         db_add_symbol_table((char *)symtab,
 185                             (char *)(symtab + tabsz), "elf", (char *)strtab);
 186                 }
 187         }
 188         db_add_symbol_table(NULL, NULL, "kld", NULL);
 189         return (1);     /* We're the default debugger. */
 190 }
 191
 192 static int
 193 db_trap(int type, int code)
 194 {
 195         jmp_buf jb;
 196         void *prev_jb;
 197         boolean_t bkpt, watchpt;
 198         const char *why;
 199
 200         /*
 201          * Don't handle the trap if the console is unavailable (i.e. it
 202          * is in graphics mode).
 203          */
 204         if (cnunavailable())
 205                 return (0);
 206
 207         bkpt = IS_BREAKPOINT_TRAP(type, code);
 208         watchpt = IS_WATCHPOINT_TRAP(type, code);
 209
 210         if (db_stop_at_pc(&bkpt)) {
 211                 if (db_inst_count) {
 212                         db_printf("After %d instructions (%d loads, %d stores),\n",
 213                             db_inst_count, db_load_count, db_store_count);
 214                 }
 215                 prev_jb = kdb_jmpbuf(jb);
 216                 if (setjmp(jb) == 0) {
 217                         db_dot = PC_REGS();
 218                         db_print_thread();
 219                         if (bkpt)
 220                                 db_printf("Breakpoint at\t");
 221                         else if (watchpt)
 222                                 db_printf("Watchpoint at\t");
 223                         else
 224                                 db_printf("Stopped at\t");
 225                         db_print_loc_and_inst(db_dot);
 226                 }
 227                 why = kdb_why;
 228                 db_script_kdbenter(why != KDB_WHY_UNSET ? why : "unknown");
 229                 db_command_loop();
 230                 (void)kdb_jmpbuf(prev_jb);
 231         }
 232
 233         db_restart_at_pc(watchpt);
 234
 235         return (1);
 236 }
 237
 238 static void
 239 db_trace_self_wrapper(void)
 240 {
 241         jmp_buf jb;
 242         void *prev_jb;
 243
 244         prev_jb = kdb_jmpbuf(jb);
 245         if (setjmp(jb) == 0)
 246                 db_trace_self();
 247         (void)kdb_jmpbuf(prev_jb);
 248 }