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
51 typedef u_int model_t;
52 #define DATAMODEL_NATIVE 0
53 int dtrace_instr_size(uchar_t *);
54 int dtrace_instr_size_isa(uchar_t *, model_t, int *);
55 #endif
56 #ifdef __NetBSD__
57 #include <dtrace_cddl.h>
58
59 typedef u_int model_t;
60 #define DATAMODEL_NATIVE 0
61 int dtrace_instr_size(uchar_t *);
62 int 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
82 typedef 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 */
91 static int
dtrace_dis_get_byte(void * p)92 dtrace_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 */
112 static int
dtrace_dis_isize(uchar_t * instr,dis_isize_t which,model_t model,int * rmindex)113 dtrace_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
138 int
dtrace_instr_size_isa(uchar_t * instr,model_t model,int * rmindex)139 dtrace_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
144 int
dtrace_instr_size(uchar_t * instr)145 dtrace_instr_size(uchar_t *instr)
146 {
147 return (dtrace_dis_isize(instr, DIS_ISIZE_INSTR, DATAMODEL_NATIVE,
148 NULL));
149 }
150