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db_access.c revision 1.21.40.1 
      1 /*	$NetBSD: db_access.c,v 1.21.40.1 2015/09/22 12:05:56 skrll 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 1.21.40.1 2015/09/22 12:05:56 skrll 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 db_expr_t
     59 db_get_value(db_addr_t addr, size_t size, bool is_signed)
     60 {
     61 	char data[sizeof(db_expr_t)] __aligned(sizeof(db_expr_t));
     62 	db_expr_t value;
     63 	size_t i;
     64 
     65 	db_read_bytes(addr, size, data);
     66 
     67 	value = 0;
     68 #if BYTE_ORDER == LITTLE_ENDIAN
     69 	for (i = size; i-- > 0;)
     70 #else /* BYTE_ORDER == BIG_ENDIAN */
     71 	for (i = 0; i < size; i++)
     72 #endif /* BYTE_ORDER */
     73 		value = (value << 8) + (data[i] & 0xFF);
     74 
     75 	if (size < sizeof(db_expr_t) && is_signed
     76 	    && (value & ((db_expr_t)1 << (8*size - 1)))) {
     77 		value |= ~(db_expr_t)0 << (8*size - 1);
     78 	}
     79 	return (value);
     80 }
     81 
     82 void
     83 db_put_value(db_addr_t addr, size_t size, db_expr_t value)
     84 {
     85 	char data[sizeof(db_expr_t)] __aligned(sizeof(db_expr_t));
     86 	size_t i;
     87 
     88 #if BYTE_ORDER == LITTLE_ENDIAN
     89 	for (i = 0; i < size; i++)
     90 #else /* BYTE_ORDER == BIG_ENDIAN */
     91 	for (i = size; i-- > 0;)
     92 #endif /* BYTE_ORDER */
     93 	{
     94 		data[i] = value & 0xFF;
     95 		value >>= 8;
     96 	}
     97 
     98 	db_write_bytes(addr, size, data);
     99 }
    100 
    101 #endif	/* _COMPILE_THIS || KGDB && SOFTWARE_SSTEP */
    102 
    103 #ifdef	_COMPILE_THIS
    104 
    105 void *
    106 db_read_ptr(const char *name)
    107 {
    108 	db_expr_t val;
    109 	void *p;
    110 
    111 	if (!db_value_of_name(name, &val)) {
    112 		db_printf("db_read_ptr: cannot find `%s'\n", name);
    113 		db_error(NULL);
    114 		/* NOTREACHED */
    115 	}
    116 	db_read_bytes((db_addr_t)val, sizeof(p), (char *)&p);
    117 	return p;
    118 }
    119 
    120 int
    121 db_read_int(const char *name)
    122 {
    123 	db_expr_t val;
    124 	int p;
    125 
    126 	if (!db_value_of_name(name, &val)) {
    127 		db_printf("db_read_int: cannot find `%s'\n", name);
    128 		db_error(NULL);
    129 		/* NOTREACHED */
    130 	}
    131 	db_read_bytes((db_addr_t)val, sizeof(p), (char *)&p);
    132 	return p;
    133 }
    134 
    135 #endif	/* _COMPILE_THIS */
    136