6/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
  51 KDB_BACKEND(ddb, db_init, db_trace_self, db_trap);
  52
  53 vm_offset_t ksym_start, ksym_end;
  54
  55 boolean_t
  56 X_db_line_at_pc(db_symtab_t *symtab, c_db_sym_t sym, char **file, int *line,
  57     db_expr_t off)
  58 {
  59         return (FALSE);
  60 }
  61
  62 c_db_sym_t
  63 X_db_lookup(db_symtab_t *symtab, const char *symbol)
  64 {
  65         c_linker_sym_t lsym;
  66         Elf_Sym *sym;
  67
  68         if (symtab->private == NULL) {
  69                 return ((c_db_sym_t)((!linker_ddb_lookup(symbol, &lsym))
  70                         ? lsym : NULL));
  71         } else {
  72                 sym = (Elf_Sym *)symtab->start;
  73                 while ((char *)sym < symtab->end) {
  74                         if (sym->st_name != 0 &&
  75                             !strcmp(symtab->private + sym->st_name, symbol))
  76                                 return ((c_db_sym_t)sym);
  77                         sym++;
  78                 }
  79         }
  80         return (NULL);
  81 }
  82
  83 c_db_sym_t
  84 X_db_search_symbol(db_symtab_t *symtab, db_addr_t off, db_strategy_t strat,
  85     db_expr_t *diffp)
  86 {
  87         c_linker_sym_t lsym;
  88         Elf_Sym *sym, *match;
  89         unsigned long diff;
  90
  91         if (symtab->private == NULL) {
  92                 if (!linker_ddb_search_symbol((caddr_t)off, &lsym, &diff)) {
  93                         *diffp = (db_expr_t)diff;
  94                         return ((c_db_sym_t)lsym);
  95                 }
  96                 return (NULL);
  97         }
  98
  99         diff = ~0UL;
 100         match = NULL;
 101         for (sym = (Elf_Sym*)symtab->start; (char*)sym < symtab->end; sym++) {
 102                 if (sym->st_name == 0)
 103                         continue;
 104                 if (off < sym->st_value)
 105                         continue;
 106                 if (ELF_ST_TYPE(sym->st_info) != STT_OBJECT &&
 107                     ELF_ST_TYPE(sym->st_info) != STT_FUNC &&
 108                     ELF_ST_TYPE(sym->st_info) != STT_NOTYPE)
 109                         continue;
 110                 if ((off - sym->st_value) > diff)
 111                         continue;
 112                 if ((off - sym->st_value) < diff) {
 113                         diff = off - sym->st_value;
 114                         match = sym;
 115                 } else {
 116                         if (match == NULL)
 117                                 match = sym;
 118                         else if (ELF_ST_BIND(match->st_info) == STB_LOCAL &&
 119                             ELF_ST_BIND(sym->st_info) != STB_LOCAL)
 120                                 match = sym;
 121                 }
 122                 if (diff == 0) {
 123                         if (strat == DB_STGY_PROC &&
 124                             ELF_ST_TYPE(sym->st_info) == STT_FUNC &&
 125                             ELF_ST_BIND(sym->st_info) != STB_LOCAL)
 126                                 break;
 127                         if (strat == DB_STGY_ANY &&
 128                             ELF_ST_BIND(sym->st_info) != STB_LOCAL)
 129                                 break;
 130                 }
 131         }
 132
 133         *diffp = (match == NULL) ? off : diff;
 134         return ((c_db_sym_t)match);
 135 }
 136
 137 boolean_t
 138 X_db_sym_numargs(db_symtab_t *symtab, c_db_sym_t sym, int *nargp,
 139     char **argp)
 140 {
 141         return (FALSE);
 142 }
 143
 144 void
 145 X_db_symbol_values(db_symtab_t *symtab, c_db_sym_t sym, const char **namep,
 146     db_expr_t *valp)
 147 {
 148         linker_symval_t lval;
 149
 150         if (symtab->private == NULL) {
 151                 linker_ddb_symbol_values((c_linker_sym_t)sym, &lval);
 152                 if (namep != NULL)
 153                         *namep = (const char*)lval.name;
 154                 if (valp != NULL)
 155                         *valp = (db_expr_t)lval.value;
 156         } else {
 157                 if (namep != NULL)
 158                         *namep = (const char *)symtab->private +
 159                             ((const Elf_Sym *)sym)->st_name;
 160                 if (valp != NULL)
 161                         *valp = (db_expr_t)((const Elf_Sym *)sym)->st_value;
 162         }
 163 }
 164
 165 static int
 166 db_init(void)
 167 {
 168         uintptr_t symtab, strtab;
 169         Elf_Size tabsz, strsz;
 170
 171         if (ksym_end > ksym_start && ksym_start != 0) {
 172                 symtab = ksym_start;
 173                 tabsz = *((Elf_Size*)symtab);
 174                 symtab += sizeof(Elf_Size);
 175                 strtab = symtab + tabsz;
 176                 strsz = *((Elf_Size*)strtab);
 177                 strtab += sizeof(Elf_Size);
 178                 if (strtab + strsz <= ksym_end) {
 179                         db_add_symbol_table((char *)symtab,
 180                             (char *)(symtab + tabsz), "elf", (char *)strtab);
 181                 }
 182         }
 183         db_add_symbol_table(NULL, NULL, "kld", NULL);
 184         return (1);     /* We're the default debugger. */
 185 }
 186
 187 static int
 188 db_trap(int type, int code)
 189 {
 190         jmp_buf jb;
 191         void *prev_jb;
 192         boolean_t bkpt, watchpt;
 193
 194         /*
 195          * Don't handle the trap if the console is unavailable (i.e. it
 196          * is in graphics mode).
 197          */
 198         if (cnunavailable())
 199                 return (0);
 200
 201         cndbctl(TRUE);
 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         cndbctl(FALSE);
 229         return (1);
 230 }