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db_access.c revision 1.18.42.2 
      1 /*	$NetBSD: db_access.c,v 1.18.42.2 2010/03/11 15:03:20 yamt 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 (at) 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 1.18.42.2 2010/03/11 15:03:20 yamt 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 */
    141