sys/platform/vkernel/i386/db_trace.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  * $FreeBSD: src/sys/i386/i386/db_trace.c,v 1.35.2.3 2002/02/21 22:31:25 silby Exp $
  27  * $DragonFly: src/sys/platform/vkernel/i386/db_trace.c,v 1.9 2008/02/03 15:10:26 nth Exp $
  28  */
  29
  30 #include <sys/param.h>
  31 #include <sys/systm.h>
  32 #include <sys/linker_set.h>
  33 #include <sys/lock.h>
  34 #include <sys/proc.h>
  35 #include <sys/reg.h>
  36
  37 #include <machine/cpu.h>
  38 #include <machine/md_var.h>
  39
  40 #include <vm/vm.h>
  41 #include <vm/vm_param.h>
  42 #include <vm/pmap.h>
  43 #include <vm/vm_map.h>
  44 #include <ddb/ddb.h>
  45 #include <dlfcn.h>      /* DLL */
  46
  47 #include <sys/user.h>
  48
  49 #include <ddb/db_access.h>
  50 #include <ddb/db_sym.h>
  51 #include <ddb/db_variables.h>
  52
  53 static int db_dr(struct db_variable *vp, db_expr_t *valuep, int op);
  54
  55 /*
  56  * Machine register set.
  57  */
  58 struct db_variable db_regs[] = {
  59         { "cs",         &ddb_regs.tf_cs,     FCN_NULL },
  60         { "ds",         &ddb_regs.tf_ds,     FCN_NULL },
  61         { "es",         &ddb_regs.tf_es,     FCN_NULL },
  62         { "fs",         &ddb_regs.tf_fs,     FCN_NULL },
  63         { "gs",         &ddb_regs.tf_gs,     FCN_NULL },
  64         { "ss",         &ddb_regs.tf_ss,     FCN_NULL },
  65         { "eax",        &ddb_regs.tf_eax,    FCN_NULL },
  66         { "ecx",        &ddb_regs.tf_ecx,    FCN_NULL },
  67         { "edx",        &ddb_regs.tf_edx,    FCN_NULL },
  68         { "ebx",        &ddb_regs.tf_ebx,    FCN_NULL },
  69         { "esp",        &ddb_regs.tf_esp,    FCN_NULL },
  70         { "ebp",        &ddb_regs.tf_ebp,    FCN_NULL },
  71         { "esi",        &ddb_regs.tf_esi,    FCN_NULL },
  72         { "edi",        &ddb_regs.tf_edi,    FCN_NULL },
  73         { "eip",        &ddb_regs.tf_eip,    FCN_NULL },
  74         { "efl",        &ddb_regs.tf_eflags, FCN_NULL },
  75         { "dr0",        NULL,                db_dr },
  76         { "dr1",        NULL,                db_dr },
  77         { "dr2",        NULL,                db_dr },
  78         { "dr3",        NULL,                db_dr },
  79         { "dr4",        NULL,                db_dr },
  80         { "dr5",        NULL,                db_dr },
  81         { "dr6",        NULL,                db_dr },
  82         { "dr7",        NULL,                db_dr },
  83 };
  84 struct db_variable *db_eregs = db_regs + sizeof(db_regs)/sizeof(db_regs[0]);
  85
  86 /*
  87  * Stack trace.
  88  */
  89 #define INKERNEL(va)    (((vm_offset_t)(va)) >= USRSTACK)
  90
  91 struct i386_frame {
  92         struct i386_frame       *f_frame;
  93         int                     f_retaddr;
  94         int                     f_arg0;
  95 };
  96
  97 #define NORMAL          0
  98 #define TRAP            1
  99 #define INTERRUPT       2
 100 #define SYSCALL         3
 101
 102 static void     db_nextframe(struct i386_frame **, db_addr_t *);
 103 static int      db_numargs(struct i386_frame *);
 104 static void     db_print_stack_entry(const char *, int, char **, int *, db_addr_t);
 105 static void     dl_symbol_values(int callpc, const char **name);
 106
 107
 108 int             db_md_set_watchpoint(db_expr_t addr, db_expr_t size);
 109 int             db_md_clr_watchpoint(db_expr_t addr, db_expr_t size);
 110 void            db_md_list_watchpoints(void);
 111
 112
 113 /*
 114  * Figure out how many arguments were passed into the frame at "fp".
 115  */
 116 static int
 117 db_numargs(struct i386_frame *fp)
 118 {
 119         int     args;
 120 #if 0
 121         int     *argp;
 122         int     inst;
 123
 124         argp = (int *)db_get_value((int)&fp->f_retaddr, 4, FALSE);
 125         /*
 126          * XXX etext is wrong for LKMs.  We should attempt to interpret
 127          * the instruction at the return address in all cases.  This
 128          * may require better fault handling.
 129          */
 130         if (argp < (int *)btext || argp >= (int *)etext) {
 131                 args = 5;
 132         } else {
 133                 inst = db_get_value((int)argp, 4, FALSE);
 134                 if ((inst & 0xff) == 0x59)      /* popl %ecx */
 135                         args = 1;
 136                 else if ((inst & 0xffff) == 0xc483)     /* addl $Ibs, %esp */
 137                         args = ((inst >> 16) & 0xff) / 4;
 138                 else
 139                         args = 5;
 140         }
 141 #endif
 142         args = 5;
 143         return(args);
 144 }
 145
 146 static void
 147 db_print_stack_entry(const char *name, int narg, char **argnp, int *argp,
 148                      db_addr_t callpc)
 149 {
 150         db_printf("%s(", name);
 151         while (narg) {
 152                 if (argnp)
 153                         db_printf("%s=", *argnp++);
 154                 db_printf("%r", db_get_value((int)argp, 4, FALSE));
 155                 argp++;
 156                 if (--narg != 0)
 157                         db_printf(",");
 158         }
 159         db_printf(") at ");
 160         db_printsym(callpc, DB_STGY_PROC);
 161         db_printf("\n");
 162 }
 163
 164 /*
 165  * Figure out the next frame up in the call stack.
 166  */
 167 static void
 168 db_nextframe(struct i386_frame **fp, db_addr_t *ip)
 169 {
 170         struct trapframe *tf;
 171         int frame_type;
 172         int eip, esp, ebp;
 173         db_expr_t offset;
 174         const char *sym, *name;
 175
 176         eip = db_get_value((int) &(*fp)->f_retaddr, 4, FALSE);
 177         ebp = db_get_value((int) &(*fp)->f_frame, 4, FALSE);
 178
 179         /*
 180          * Figure out frame type.
 181          */
 182
 183         frame_type = NORMAL;
 184
 185         sym = db_search_symbol(eip, DB_STGY_ANY, &offset);
 186         db_symbol_values(sym, &name, NULL);
 187         dl_symbol_values(eip, &name);
 188         if (name != NULL) {
 189                 if (!strcmp(name, "calltrap")) {
 190                         frame_type = TRAP;
 191                 } else if (!strncmp(name, "Xresume", 7)) {
 192                         frame_type = INTERRUPT;
 193                 } else if (!strcmp(name, "_Xsyscall")) {
 194                         frame_type = SYSCALL;
 195                 }
 196         }
 197
 198         /*
 199          * Normal frames need no special processing.
 200          */
 201         if (frame_type == NORMAL) {
 202                 *ip = (db_addr_t) eip;
 203                 *fp = (struct i386_frame *) ebp;
 204                 return;
 205         }
 206
 207         db_print_stack_entry(name, 0, 0, 0, eip);
 208
 209         /*
 210          * Point to base of trapframe which is just above the
 211          * current frame.
 212          */
 213         tf = (struct trapframe *) ((int)*fp + 8);
 214
 215 #if 0
 216         esp = (ISPL(tf->tf_cs) == SEL_UPL) ?  tf->tf_esp : (int)&tf->tf_esp;
 217 #endif
 218         esp = (int)&tf->tf_esp;
 219
 220         switch (frame_type) {
 221         case TRAP:
 222                 {
 223                         eip = tf->tf_eip;
 224                         ebp = tf->tf_ebp;
 225                         db_printf(
 226                     "--- trap %#r, eip = %#r, esp = %#r, ebp = %#r ---\n",
 227                             tf->tf_trapno, eip, esp, ebp);
 228                 }
 229                 break;
 230         case SYSCALL:
 231                 {
 232                         eip = tf->tf_eip;
 233                         ebp = tf->tf_ebp;
 234                         db_printf(
 235                     "--- syscall %#r, eip = %#r, esp = %#r, ebp = %#r ---\n",
 236                             tf->tf_eax, eip, esp, ebp);
 237                 }
 238                 break;
 239         case INTERRUPT:
 240                 tf = (struct trapframe *)((int)*fp + 16);
 241                 {
 242                         eip = tf->tf_eip;
 243                         ebp = tf->tf_ebp;
 244                         db_printf(
 245                     "--- interrupt, eip = %#r, esp = %#r, ebp = %#r ---\n",
 246                             eip, esp, ebp);
 247                 }
 248                 break;
 249         default:
 250                 break;
 251         }
 252
 253         *ip = (db_addr_t) eip;
 254         *fp = (struct i386_frame *) ebp;
 255 }
 256
 257 void
 258 db_stack_trace_cmd(db_expr_t addr, boolean_t have_addr, db_expr_t count,
 259                    char *modif)
 260 {
 261         struct i386_frame *frame;
 262         int *argp;
 263         db_addr_t callpc;
 264         boolean_t first;
 265         int i;
 266
 267         if (count == -1)
 268                 count = 1024;
 269
 270         if (!have_addr) {
 271                 frame = (struct i386_frame *)BP_REGS(&ddb_regs);
 272                 if (frame == NULL)
 273                         frame = (struct i386_frame *)(SP_REGS(&ddb_regs) - 4);
 274                 callpc = PC_REGS(&ddb_regs);
 275         } else {
 276                 /*
 277                  * Look for something that might be a frame pointer, just as
 278                  * a convenience.
 279                  */
 280                 frame = (struct i386_frame *)addr;
 281                 for (i = 0; i < 4096; i += 4) {
 282                         struct i386_frame *check;
 283
 284                         check = (struct i386_frame *)db_get_value((int)((char *)&frame->f_frame + i), 4, FALSE);
 285                         if ((char *)check - (char *)frame >= 0 &&
 286                             (char *)check - (char *)frame < 4096
 287                         ) {
 288                                 break;
 289                         }
 290                         db_printf("%p does not look like a stack frame, skipping\n", (char *)&frame->f_frame + i);
 291                 }
 292                 if (i == 4096) {
 293                         db_printf("Unable to find anything that looks like a stack frame\n");
 294                         return;
 295                 }
 296                 frame = (void *)((char *)frame + i);
 297                 db_printf("Trace beginning at frame %p\n", frame);
 298                 callpc = (db_addr_t)db_get_value((int)&frame->f_retaddr, 4, FALSE);
 299         }
 300
 301         first = TRUE;
 302         while (count--) {
 303                 struct i386_frame *actframe;
 304                 int             narg;
 305                 const char *    name;
 306                 db_expr_t       offset;
 307                 c_db_sym_t      sym;
 308 #define MAXNARG 16
 309                 char    *argnames[MAXNARG], **argnp = NULL;
 310
 311                 sym = db_search_symbol(callpc, DB_STGY_ANY, &offset);
 312                 db_symbol_values(sym, &name, NULL);
 313                 dl_symbol_values(callpc, &name);
 314
 315                 /*
 316                  * Attempt to determine a (possibly fake) frame that gives
 317                  * the caller's pc.  It may differ from `frame' if the
 318                  * current function never sets up a standard frame or hasn't
 319                  * set one up yet or has just discarded one.  The last two
 320                  * cases can be guessed fairly reliably for code generated
 321                  * by gcc.  The first case is too much trouble to handle in
 322                  * general because the amount of junk on the stack depends
 323                  * on the pc (the special handling of "calltrap", etc. in
 324                  * db_nextframe() works because the `next' pc is special).
 325                  */
 326                 actframe = frame;
 327                 if (first) {
 328                         if (!have_addr) {
 329                                 int instr;
 330
 331                                 instr = db_get_value(callpc, 4, FALSE);
 332                                 if ((instr & 0x00ffffff) == 0x00e58955) {
 333                                         /* pushl %ebp; movl %esp, %ebp */
 334                                         actframe = (struct i386_frame *)
 335                                             (SP_REGS(&ddb_regs) - 4);
 336                                 } else if ((instr & 0x0000ffff) == 0x0000e589) {
 337                                         /* movl %esp, %ebp */
 338                                         actframe = (struct i386_frame *)
 339                                             SP_REGS(&ddb_regs);
 340                                         if (ddb_regs.tf_ebp == 0) {
 341                                                 /* Fake caller's frame better. */
 342                                                 frame = actframe;
 343                                         }
 344                                 } else if ((instr & 0x000000ff) == 0x000000c3) {
 345                                         /* ret */
 346                                         actframe = (struct i386_frame *)
 347                                             (SP_REGS(&ddb_regs) - 4);
 348                                 } else if (offset == 0) {
 349                                         /* Probably a symbol in assembler code. */
 350                                         actframe = (struct i386_frame *)
 351                                             (SP_REGS(&ddb_regs) - 4);
 352                                 }
 353                         } else if (name != NULL &&
 354                                    strcmp(name, "fork_trampoline") == 0) {
 355                                 /*
 356                                  * Don't try to walk back on a stack for a
 357                                  * process that hasn't actually been run yet.
 358                                  */
 359                                 db_print_stack_entry(name, 0, 0, 0, callpc);
 360                                 break;
 361                         }
 362                         first = FALSE;
 363                 }
 364
 365                 argp = &actframe->f_arg0;
 366                 narg = MAXNARG;
 367                 if (sym != NULL && db_sym_numargs(sym, &narg, argnames)) {
 368                         argnp = argnames;
 369                 } else {
 370                         narg = db_numargs(frame);
 371                 }
 372
 373                 db_print_stack_entry(name, narg, argnp, argp, callpc);
 374
 375                 if (actframe != frame) {
 376                         /* `frame' belongs to caller. */
 377                         callpc = (db_addr_t)
 378                             db_get_value((int)&actframe->f_retaddr, 4, FALSE);
 379                         continue;
 380                 }
 381
 382                 db_nextframe(&frame, &callpc);
 383                 if (frame == 0)
 384                         break;
 385         }
 386 }
 387
 388 void
 389 db_print_backtrace(void)
 390 {
 391         register_t  ebp;
 392
 393         __asm __volatile("movl %%ebp, %0" : "=r" (ebp));
 394         db_stack_trace_cmd(ebp, 1, -1, NULL);
 395 }
 396
 397 static int
 398 db_dr(struct db_variable *vp, db_expr_t *valuep, int op)
 399 {
 400         if (op == DB_VAR_GET)
 401                 *valuep = 0;
 402         return(-1);
 403 }
 404
 405 int
 406 db_md_set_watchpoint(db_expr_t addr, db_expr_t size)
 407 {
 408         return(-1);
 409 }
 410
 411 int
 412 db_md_clr_watchpoint(db_expr_t addr, db_expr_t size)
 413 {
 414         return(-1);
 415 }
 416
 417 void
 418 db_md_list_watchpoints(void)
 419 {
 420         /* no hardware watchpoints in vkernel */
 421 }
 422
 423 /*
 424  * See if dladdr() can get the symbol name via the standard dynamic loader.
 425  */
 426 static
 427 void
 428 dl_symbol_values(int callpc, const char **name)
 429 {
 430         Dl_info info;
 431
 432         if (*name == NULL) {
 433                 if (dladdr((const void *)callpc, &info) != 0) {
 434                         if (info.dli_saddr <= (const void *)callpc)
 435                                 *name = info.dli_sname;
 436                 }
 437         }
 438 }
 439