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 static dbbe_trace_thread_f db_trace_thread_wrapper;
  55
  56 KDB_BACKEND(ddb, db_init, db_trace_self_wrapper, db_trace_thread_wrapper,
  57     db_trap);
  58
  59 vm_offset_t ksym_start, ksym_end;
  60
  61 boolean_t
  62 X_db_line_at_pc(db_symtab_t *symtab, c_db_sym_t sym, char **file, int *line,
  63     db_expr_t off)
  64 {
  65         return (FALSE);
  66 }
  67
  68 c_db_sym_t
  69 X_db_lookup(db_symtab_t *symtab, const char *symbol)
  70 {
  71         c_linker_sym_t lsym;
  72         Elf_Sym *sym;
  73
  74         if (symtab->private == NULL) {
  75                 return ((c_db_sym_t)((!linker_ddb_lookup(symbol, &lsym))
  76                         ? lsym : NULL));
  77         } else {
  78                 sym = (Elf_Sym *)symtab->start;
  79                 while ((char *)sym < symtab->end) {
  80                         if (sym->st_name != 0 &&
  81                             !strcmp(symtab->private + sym->st_name, symbol))
  82                                 return ((c_db_sym_t)sym);
  83                         sym++;
  84                 }
  85         }
  86         return (NULL);
  87 }
  88
  89 c_db_sym_t
  90 X_db_search_symbol(db_symtab_t *symtab, db_addr_t off, db_strategy_t strat,
  91     db_expr_t *diffp)
  92 {
  93         c_linker_sym_t lsym;
  94         Elf_Sym *sym, *match;
  95         unsigned long diff;
  96
  97         if (symtab->private == NULL) {
  98                 if (!linker_ddb_search_symbol((caddr_t)off, &lsym, &diff)) {
  99                         *diffp = (db_expr_t)diff;
 100                         return ((c_db_sym_t)lsym);
 101                 }
 102                 return (NULL);
 103         }
 104
 105         diff = ~0UL;
 106         match = NULL;
 107         for (sym = (Elf_Sym*)symtab->start; (char*)sym < symtab->end; sym++) {
 108                 if (sym->st_name == 0)
 109                         continue;
 110                 if (off < sym->st_value)
 111                         continue;
 112                 if (ELF_ST_TYPE(sym->st_info) != STT_OBJECT &&
 113                     ELF_ST_TYPE(sym->st_info) != STT_FUNC &&
 114                     ELF_ST_TYPE(sym->st_info) != STT_NOTYPE)
 115                         continue;
 116                 if ((off - sym->st_value) > diff)
 117                         continue;
 118                 if ((off - sym->st_value) < diff) {
 119                         diff = off - sym->st_value;
 120                         match = sym;
 121                 } else {
 122                         if (match == NULL)
 123                                 match = sym;
 124                         else if (ELF_ST_BIND(match->st_info) == STB_LOCAL &&
 125                             ELF_ST_BIND(sym->st_info) != STB_LOCAL)
 126                                 match = sym;
 127                 }
 128                 if (diff == 0) {
 129                         if (strat == DB_STGY_PROC &&
 130                             ELF_ST_TYPE(sym->st_info) == STT_FUNC &&
 131                             ELF_ST_BIND(sym->st_info) != STB_LOCAL)
 132                                 break;
 133                         if (strat == DB_STGY_ANY &&
 134                             ELF_ST_BIND(sym->st_info) != STB_LOCAL)
 135                                 break;
 136                 }
 137         }
 138
 139         *diffp = (match == NULL) ? off : diff;
 140         return ((c_db_sym_t)match);
 141 }
 142
 143 boolean_t
 144 X_db_sym_numargs(db_symtab_t *symtab, c_db_sym_t sym, int *nargp,
 145     char **argp)
 146 {
 147         return (FALSE);
 148 }
 149
 150 void
 151 X_db_symbol_values(db_symtab_t *symtab, c_db_sym_t sym, const char **namep,
 152     db_expr_t *valp)
 153 {
 154         linker_symval_t lval;
 155
 156         if (symtab->private == NULL) {
 157                 linker_ddb_symbol_values((c_linker_sym_t)sym, &lval);
 158                 if (namep != NULL)
 159                         *namep = (const char*)lval.name;
 160                 if (valp != NULL)
 161                         *valp = (db_expr_t)lval.value;
 162         } else {
 163                 if (namep != NULL)
 164                         *namep = (const char *)symtab->private +
 165                             ((const Elf_Sym *)sym)->st_name;
 166                 if (valp != NULL)
 167                         *valp = (db_expr_t)((const Elf_Sym *)sym)->st_value;
 168         }
 169 }
 170
 171 static int
 172 db_init(void)
 173 {
 174         uintptr_t symtab, strtab;
 175         Elf_Size tabsz, strsz;
 176
 177         db_command_init();
 178         if (ksym_end > ksym_start && ksym_start != 0) {
 179                 symtab = ksym_start;
 180                 tabsz = *((Elf_Size*)symtab);
 181                 symtab += sizeof(Elf_Size);
 182                 strtab = symtab + tabsz;
 183                 strsz = *((Elf_Size*)strtab);
 184                 strtab += sizeof(Elf_Size);
 185                 if (strtab + strsz <= ksym_end) {
 186                         db_add_symbol_table((char *)symtab,
 187                             (char *)(symtab + tabsz), "elf", (char *)strtab);
 188                 }
 189         }
 190         db_add_symbol_table(NULL, NULL, "kld", NULL);
 191         return (1);     /* We're the default debugger. */
 192 }
 193
 194 static int
 195 db_trap(int type, int code)
 196 {
 197         jmp_buf jb;
 198         void *prev_jb;
 199         boolean_t bkpt, watchpt;
 200         const char *why;
 201
 202         /*
 203          * Don't handle the trap if the console is unavailable (i.e. it
 204          * is in graphics mode).
 205          */
 206         if (cnunavailable())
 207                 return (0);
 208
 209         bkpt = IS_BREAKPOINT_TRAP(type, code);
 210         watchpt = IS_WATCHPOINT_TRAP(type, code);
 211
 212         if (db_stop_at_pc(&bkpt)) {
 213                 if (db_inst_count) {
 214                         db_printf("After %d instructions (%d loads, %d stores),\n",
 215                             db_inst_count, db_load_count, db_store_count);
 216                 }
 217                 prev_jb = kdb_jmpbuf(jb);
 218                 if (setjmp(jb) == 0) {
 219                         db_dot = PC_REGS();
 220                         db_print_thread();
 221                         if (bkpt)
 222                                 db_printf("Breakpoint at\t");
 223                         else if (watchpt)
 224                                 db_printf("Watchpoint at\t");
 225                         else
 226                                 db_printf("Stopped at\t");
 227                         db_print_loc_and_inst(db_dot);
 228                 }
 229                 why = kdb_why;
 230                 db_script_kdbenter(why != KDB_WHY_UNSET ? why : "unknown");
 231                 db_command_loop();
 232                 (void)kdb_jmpbuf(prev_jb);
 233         }
 234
 235         db_restart_at_pc(watchpt);
 236
 237         return (1);
 238 }
 239
 240 static void
 241 db_trace_self_wrapper(void)
 242 {
 243         jmp_buf jb;
 244         void *prev_jb;
 245
 246         prev_jb = kdb_jmpbuf(jb);
 247         if (setjmp(jb) == 0)
 248                 db_trace_self();
 249         (void)kdb_jmpbuf(prev_jb);
 250 }
 251
 252 static void
 253 db_trace_thread_wrapper(struct thread *td)
 254 {
 255         jmp_buf jb;
 256         void *prev_jb;
 257
 258         prev_jb = kdb_jmpbuf(jb);
 259         if (setjmp(jb) == 0)
 260                 db_trace_thread(td, -1);
 261         (void)kdb_jmpbuf(prev_jb);
 262 }