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