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#include <sys/types.h>
31#include <sys/param.h>
32#include <sys/proc.h>
33#ifdef illumos
34#include <sys/cmn_err.h>
35#include <sys/archsystm.h>
36#include <sys/copyops.h>
37#include <vm/seg_enum.h>
38#include <sys/privregs.h>
39#else
40#include <sys/cred.h>
41#include <cddl/dev/dtrace/dtrace_cddl.h>
42
43typedef	u_int			model_t;
44#define	DATAMODEL_NATIVE	0
45int dtrace_dis_get_byte(void *);
46int dtrace_instr_size(uint8_t *);
47int dtrace_instr_size_isa(uint8_t *, model_t, int *);
48#endif
49
50#include <dis_tables.h>
51
52/*
53 * This subsystem (with the minor exception of the instr_size() function) is
54 * is called from DTrace probe context.  This imposes several requirements on
55 * the implementation:
56 *
57 * 1. External subsystems and functions may not be referenced.  The one current
58 *    exception is for cmn_err, but only to signal the detection of table
59 *    errors.  Assuming the tables are correct, no combination of input is to
60 *    trigger a cmn_err call.
61 *
62 * 2. These functions can't be allowed to be traced.  To prevent this,
63 *    all functions in the probe path (everything except instr_size()) must
64 *    have names that begin with "dtrace_".
65 */
66
67typedef enum dis_isize {
68	DIS_ISIZE_INSTR,
69	DIS_ISIZE_OPERAND
70} dis_isize_t;
71
72
73/*
74 * get a byte from instruction stream
75 */
76int
77dtrace_dis_get_byte(void *p)
78{
79	int ret;
80	uint8_t **instr = p;
81
82	ret = **instr;
83	*instr += 1;
84
85	return (ret);
86}
87
88/*
89 * Returns either the size of a given instruction, in bytes, or the size of that
90 * instruction's memory access (if any), depending on the value of `which'.
91 * If a programming error in the tables is detected, the system will panic to
92 * ease diagnosis.  Invalid instructions will not be flagged.  They will appear
93 * to have an instruction size between 1 and the actual size, and will be
94 * reported as having no memory impact.
95 */
96/* ARGSUSED2 */
97static int
98dtrace_dis_isize(uint8_t *instr, dis_isize_t which, model_t model, int *rmindex)
99{
100	int sz;
101	dis86_t	x;
102	uint_t mode = SIZE32;
103
104	mode = (model == DATAMODEL_LP64) ? SIZE64 : SIZE32;
105
106	x.d86_data = (void **)&instr;
107	x.d86_get_byte = dtrace_dis_get_byte;
108	x.d86_check_func = NULL;
109
110	if (dtrace_disx86(&x, mode) != 0)
111		return (-1);
112
113	if (which == DIS_ISIZE_INSTR)
114		sz = x.d86_len;		/* length of the instruction */
115	else
116		sz = x.d86_memsize;	/* length of memory operand */
117
118	if (rmindex != NULL)
119		*rmindex = x.d86_rmindex;
120	return (sz);
121}
122
123int
124dtrace_instr_size_isa(uint8_t *instr, model_t model, int *rmindex)
125{
126	return (dtrace_dis_isize(instr, DIS_ISIZE_INSTR, model, rmindex));
127}
128
129int
130dtrace_instr_size(uint8_t *instr)
131{
132	return (dtrace_dis_isize(instr, DIS_ISIZE_INSTR, DATAMODEL_NATIVE,
133	    NULL));
134}
135