sys/ddb/db_access.c

   1 /*      $NetBSD: db_access.c,v 1.20 2009/09/27 18:24:23 bsh Exp $       */
   2
   3 /*
   4  * Mach Operating System
   5  * Copyright (c) 1991,1990 Carnegie Mellon University
   6  * All Rights Reserved.
   7  *
   8  * Permission to use, copy, modify and distribute this software and its
   9  * documentation is hereby granted, provided that both the copyright
  10  * notice and this permission notice appear in all copies of the
  11  * software, derivative works or modified versions, and any portions
  12  * thereof, and that both notices appear in supporting documentation.
  13  *
  14  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
  15  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
  16  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
  17  *
  18  * Carnegie Mellon requests users of this software to return to
  19  *
  20  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
  21  *  School of Computer Science
  22  *  Carnegie Mellon University
  23  *  Pittsburgh PA 15213-3890
  24  *
  25  * any improvements or extensions that they make and grant Carnegie the
  26  * rights to redistribute these changes.
  27  *
  28  *      Author: David B. Golub, Carnegie Mellon University
  29  *      Date:   7/90
  30  */
  31
  32 #include <sys/cdefs.h>
  33 __KERNEL_RCSID(0, "$NetBSD: db_access.c,v 1.20 2009/09/27 18:24:23 bsh Exp $");
  34
  35 #if defined(_KERNEL_OPT)
  36 #include "opt_kgdb.h"
  37 #endif
  38
  39 #include <sys/param.h>
  40 #include <sys/proc.h>
  41 #include <sys/endian.h>
  42
  43 #include <ddb/ddb.h>
  44
  45 /*
  46  * Access unaligned data items on aligned (longword)
  47  * boundaries.
  48  *
  49  * This file is shared by ddb, kgdb and crash(8).
  50  */
  51
  52 #if defined(DDB) || !defined(DDB) && !defined(KGDB)
  53 #define _COMPILE_THIS
  54 #endif
  55
  56 #if defined(_COMPILE_THIS) || defined(KGDB) && defined(SOFTWARE_SSTEP)
  57
  58 const int db_extend[] = {       /* table for sign-extending */
  59         0,
  60         0xFFFFFF80,
  61         0xFFFF8000,
  62         0xFF800000
  63 };
  64
  65 db_expr_t
  66 db_get_value(db_addr_t addr, size_t size, bool is_signed)
  67 {
  68         char data[sizeof(db_expr_t)];
  69         db_expr_t value;
  70         size_t i;
  71
  72         db_read_bytes(addr, size, data);
  73
  74         value = 0;
  75 #if BYTE_ORDER == LITTLE_ENDIAN
  76         for (i = size; i-- > 0;)
  77 #else /* BYTE_ORDER == BIG_ENDIAN */
  78         for (i = 0; i < size; i++)
  79 #endif /* BYTE_ORDER */
  80                 value = (value << 8) + (data[i] & 0xFF);
  81
  82         if (size < 4 && is_signed && (value & db_extend[size]) != 0)
  83                 value |= db_extend[size];
  84         return (value);
  85 }
  86
  87 void
  88 db_put_value(db_addr_t addr, size_t size, db_expr_t value)
  89 {
  90         char data[sizeof(db_expr_t)];
  91         size_t i;
  92
  93 #if BYTE_ORDER == LITTLE_ENDIAN
  94         for (i = 0; i < size; i++)
  95 #else /* BYTE_ORDER == BIG_ENDIAN */
  96         for (i = size; i-- > 0;)
  97 #endif /* BYTE_ORDER */
  98         {
  99                 data[i] = value & 0xFF;
 100                 value >>= 8;
 101         }
 102
 103         db_write_bytes(addr, size, data);
 104 }
 105
 106 #endif  /* _COMPILE_THIS || KGDB && SOFTWARE_SSTEP */
 107
 108 #ifdef  _COMPILE_THIS
 109
 110 void *
 111 db_read_ptr(const char *name)
 112 {
 113         db_expr_t val;
 114         void *p;
 115
 116         if (!db_value_of_name(name, &val)) {
 117                 db_printf("db_read_ptr: cannot find `%s'\n", name);
 118                 db_error(NULL);
 119                 /* NOTREACHED */
 120         }
 121         db_read_bytes((db_addr_t)val, sizeof(p), (char *)&p);
 122         return p;
 123 }
 124
 125 int
 126 db_read_int(const char *name)
 127 {
 128         db_expr_t val;
 129         int p;
 130
 131         if (!db_value_of_name(name, &val)) {
 132                 db_printf("db_read_int: cannot find `%s'\n", name);
 133                 db_error(NULL);
 134                 /* NOTREACHED */
 135         }
 136         db_read_bytes((db_addr_t)val, sizeof(p), (char *)&p);
 137         return p;
 138 }
 139
 140 #endif  /* _COMPILE_THIS */