1/*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License, Version 1.0 only
6 * (the "License"). You may not use this file except in compliance
7 * with the License.
8 *
9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10 * or http://www.opensolaris.org/os/licensing.
11 * See the License for the specific language governing permissions
12 * and limitations under the License.
13 *
14 * When distributing Covered Code, include this CDDL HEADER in each
15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16 * If applicable, add the following below this CDDL HEADER, with the
17 * fields enclosed by brackets "[]" replaced with your own identifying
18 * information: Portions Copyright [yyyy] [name of copyright owner]
19 *
20 * CDDL HEADER END
21 */
22/*
23 * Copyright 2005 Sun Microsystems, Inc. All rights reserved.
24 * Use is subject to license terms.
25 */
26
27/* Copyright (c) 1988 AT&T */
28/* All Rights Reserved */
29
30
31/*
32 * #pragma ident "@(#)instr_size.c 1.14 05/07/08 SMI"
33 */
34
35#include <sys/dtrace.h>
36#include <sys/dtrace_glue.h>
37
38#include <sys/dis_tables.h>
39
40/*
41 * This subsystem (with the minor exception of the instr_size() function) is
42 * is called from DTrace probe context. This imposes several requirements on
43 * the implementation:
44 *
45 * 1. External subsystems and functions may not be referenced. The one current
46 * exception is for cmn_err, but only to signal the detection of table
47 * errors. Assuming the tables are correct, no combination of input is to
48 * trigger a cmn_err call.
49 *
50 * 2. These functions can't be allowed to be traced. To prevent this,
51 * all functions in the probe path (everything except instr_size()) must
52 * have names that begin with "dtrace_".
53 */
54
55typedef enum dis_isize {
56 DIS_ISIZE_INSTR,
57 DIS_ISIZE_OPERAND
58} dis_isize_t;
59
60
61/*
62 * get a byte from instruction stream
63 */
64static int
65dtrace_dis_get_byte(void *p)
66{
67 int ret;
68 uchar_t **instr = p;
69
70 ret = **instr;
71 *instr += 1;
72
73 return (ret);
74}
75
76/*
77 * Returns either the size of a given instruction, in bytes, or the size of that
78 * instruction's memory access (if any), depending on the value of `which'.
79 * If a programming error in the tables is detected, the system will panic to
80 * ease diagnosis. Invalid instructions will not be flagged. They will appear
81 * to have an instruction size between 1 and the actual size, and will be
82 * reported as having no memory impact.
83 */
84/* ARGSUSED2 */
85static int
86dtrace_dis_isize(uchar_t *instr, dis_isize_t which, model_t model, int *rmindex)
87{
88 int sz;
89 dis86_t x;
90 uint_t mode = SIZE32;
91
92 mode = (model == DATAMODEL_LP64) ? SIZE64 : SIZE32;
93
94 x.d86_data = (void **)&instr;
95 x.d86_get_byte = dtrace_dis_get_byte;
96 x.d86_check_func = NULL;
97
98 if (dtrace_disx86(&x, mode) != 0)
99 return (-1);
100
101 if (which == DIS_ISIZE_INSTR)
102 sz = x.d86_len; /* length of the instruction */
103 else
104 sz = x.d86_memsize; /* length of memory operand */
105
106 if (rmindex != NULL)
107 *rmindex = x.d86_rmindex;
108 return (sz);
109}
110
111int
112dtrace_instr_size_isa(uchar_t *instr, model_t model, int *rmindex)
113{
114 return (dtrace_dis_isize(instr, DIS_ISIZE_INSTR, model, rmindex));
115}
116
117int
118dtrace_instr_size(uchar_t *instr)
119{
120 return (dtrace_dis_isize(instr, DIS_ISIZE_INSTR, DATAMODEL_NATIVE,
121 NULL));
122}
123