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