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 #ifdef illumos
32 #pragma ident "@(#)instr_size.c 1.14 05/07/08 SMI"
33 #endif
34
35 #include <sys/types.h>
36 #include <sys/param.h>
37 #include <sys/proc.h>
38 #ifdef illumos
39 #include <sys/cmn_err.h>
40 #include <sys/archsystm.h>
41 #include <sys/copyops.h>
42 #include <vm/seg_enum.h>
43 #include <sys/privregs.h>
44 #else
45 #include <sys/cred.h>
46 #include <cddl/dev/dtrace/dtrace_cddl.h>
47
48 typedef u_int model_t;
49 #define DATAMODEL_NATIVE 0
50 int dtrace_instr_size(uint8_t *);
51 int dtrace_instr_size_isa(uint8_t *, model_t, int *);
52 #endif
53
54 #include <dis_tables.h>
55
56 /*
57 * This subsystem (with the minor exception of the instr_size() function) is
58 * is called from DTrace probe context. This imposes several requirements on
59 * the implementation:
60 *
61 * 1. External subsystems and functions may not be referenced. The one current
62 * exception is for cmn_err, but only to signal the detection of table
63 * errors. Assuming the tables are correct, no combination of input is to
64 * trigger a cmn_err call.
65 *
66 * 2. These functions can't be allowed to be traced. To prevent this,
67 * all functions in the probe path (everything except instr_size()) must
68 * have names that begin with "dtrace_".
69 */
70
71 typedef enum dis_isize {
72 DIS_ISIZE_INSTR,
73 DIS_ISIZE_OPERAND
74 } dis_isize_t;
75
76
77 /*
78 * get a byte from instruction stream
79 */
80 static int
dtrace_dis_get_byte(void * p)81 dtrace_dis_get_byte(void *p)
82 {
83 int ret;
84 uint8_t **instr = p;
85
86 ret = **instr;
87 *instr += 1;
88
89 return (ret);
90 }
91
92 /*
93 * Returns either the size of a given instruction, in bytes, or the size of that
94 * instruction's memory access (if any), depending on the value of `which'.
95 * If a programming error in the tables is detected, the system will panic to
96 * ease diagnosis. Invalid instructions will not be flagged. They will appear
97 * to have an instruction size between 1 and the actual size, and will be
98 * reported as having no memory impact.
99 */
100 /* ARGSUSED2 */
101 static int
dtrace_dis_isize(uint8_t * instr,dis_isize_t which,model_t model,int * rmindex)102 dtrace_dis_isize(uint8_t *instr, dis_isize_t which, model_t model, int *rmindex)
103 {
104 int sz;
105 dis86_t x;
106 uint_t mode = SIZE32;
107
108 mode = (model == DATAMODEL_LP64) ? SIZE64 : SIZE32;
109
110 x.d86_data = (void **)&instr;
111 x.d86_get_byte = dtrace_dis_get_byte;
112 x.d86_check_func = NULL;
113
114 if (dtrace_disx86(&x, mode) != 0)
115 return (-1);
116
117 if (which == DIS_ISIZE_INSTR)
118 sz = x.d86_len; /* length of the instruction */
119 else
120 sz = x.d86_memsize; /* length of memory operand */
121
122 if (rmindex != NULL)
123 *rmindex = x.d86_rmindex;
124 return (sz);
125 }
126
127 int
dtrace_instr_size_isa(uint8_t * instr,model_t model,int * rmindex)128 dtrace_instr_size_isa(uint8_t *instr, model_t model, int *rmindex)
129 {
130 return (dtrace_dis_isize(instr, DIS_ISIZE_INSTR, model, rmindex));
131 }
132
133 int
dtrace_instr_size(uint8_t * instr)134 dtrace_instr_size(uint8_t *instr)
135 {
136 return (dtrace_dis_isize(instr, DIS_ISIZE_INSTR, DATAMODEL_NATIVE,
137 NULL));
138 }
139