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 * $FreeBSD: head/sys/cddl/dev/dtrace/x86/instr_size.c 303050 2016-07-20 00:02:10Z markj $
23 */
24/*
25 * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
26 * Use is subject to license terms.
27 */
28
29/*	Copyright (c) 1988 AT&T	*/
30/*	  All Rights Reserved	*/
31
32
33#ifdef illumos
34#pragma ident	"@(#)instr_size.c	1.14	05/07/08 SMI"
35#endif
36
37#include <sys/types.h>
38#include <sys/proc.h>
39#include <sys/param.h>
40#ifdef illumos
41#include <sys/cmn_err.h>
42#include <sys/archsystm.h>
43#include <sys/copyops.h>
44#include <vm/seg_enum.h>
45#include <sys/privregs.h>
46#endif
47#ifdef __FreeBSD__
48#include <sys/cred.h>
49#include <cddl/dev/dtrace/dtrace_cddl.h>
50
51typedef	u_int			model_t;
52#define	DATAMODEL_NATIVE	0
53int dtrace_instr_size(uchar_t *);
54int dtrace_instr_size_isa(uchar_t *, model_t, int *);
55#endif
56#ifdef __NetBSD__
57#include <dtrace_cddl.h>
58
59typedef	u_int			model_t;
60#define	DATAMODEL_NATIVE	0
61int dtrace_instr_size(uchar_t *);
62int dtrace_instr_size_isa(uchar_t *, model_t, int *);
63#endif
64
65#include <dis_tables.h>
66
67/*
68 * This subsystem (with the minor exception of the instr_size() function) is
69 * is called from DTrace probe context.  This imposes several requirements on
70 * the implementation:
71 *
72 * 1. External subsystems and functions may not be referenced.  The one current
73 *    exception is for cmn_err, but only to signal the detection of table
74 *    errors.  Assuming the tables are correct, no combination of input is to
75 *    trigger a cmn_err call.
76 *
77 * 2. These functions can't be allowed to be traced.  To prevent this,
78 *    all functions in the probe path (everything except instr_size()) must
79 *    have names that begin with "dtrace_".
80 */
81
82typedef enum dis_isize {
83	DIS_ISIZE_INSTR,
84	DIS_ISIZE_OPERAND
85} dis_isize_t;
86
87
88/*
89 * get a byte from instruction stream
90 */
91static int
92dtrace_dis_get_byte(void *p)
93{
94	int ret;
95	uchar_t **instr = p;
96
97	ret = **instr;
98	*instr += 1;
99
100	return (ret);
101}
102
103/*
104 * Returns either the size of a given instruction, in bytes, or the size of that
105 * instruction's memory access (if any), depending on the value of `which'.
106 * If a programming error in the tables is detected, the system will panic to
107 * ease diagnosis.  Invalid instructions will not be flagged.  They will appear
108 * to have an instruction size between 1 and the actual size, and will be
109 * reported as having no memory impact.
110 */
111/* ARGSUSED2 */
112static int
113dtrace_dis_isize(uchar_t *instr, dis_isize_t which, model_t model, int *rmindex)
114{
115	int sz;
116	dis86_t	x;
117	uint_t mode = SIZE32;
118
119	mode = (model == DATAMODEL_LP64) ? SIZE64 : SIZE32;
120
121	x.d86_data = (void **)&instr;
122	x.d86_get_byte = dtrace_dis_get_byte;
123	x.d86_check_func = NULL;
124
125	if (dtrace_disx86(&x, mode) != 0)
126		return (-1);
127
128	if (which == DIS_ISIZE_INSTR)
129		sz = x.d86_len;		/* length of the instruction */
130	else
131		sz = x.d86_memsize;	/* length of memory operand */
132
133	if (rmindex != NULL)
134		*rmindex = x.d86_rmindex;
135	return (sz);
136}
137
138int
139dtrace_instr_size_isa(uchar_t *instr, model_t model, int *rmindex)
140{
141	return (dtrace_dis_isize(instr, DIS_ISIZE_INSTR, model, rmindex));
142}
143
144int
145dtrace_instr_size(uchar_t *instr)
146{
147	return (dtrace_dis_isize(instr, DIS_ISIZE_INSTR, DATAMODEL_NATIVE,
148	    NULL));
149}
150