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 #pragma ident "%Z%%M% %I% %E% SMI"
32
33 #include <sys/proc.h>
34 #include <sys/param.h>
35 #include <sys/cmn_err.h>
36 #include <sys/archsystm.h>
37 #include <sys/copyops.h>
38 #include <vm/seg_enum.h>
39 #include <sys/privregs.h>
40
41 #include <dis_tables.h>
42
43 /*
44 * This subsystem (with the minor exception of the instr_size() function) is
45 * is called from DTrace probe context. This imposes several requirements on
46 * the implementation:
47 *
48 * 1. External subsystems and functions may not be referenced. The one current
49 * exception is for cmn_err, but only to signal the detection of table
50 * errors. Assuming the tables are correct, no combination of input is to
51 * trigger a cmn_err call.
52 *
53 * 2. These functions can't be allowed to be traced. To prevent this,
54 * all functions in the probe path (everything except instr_size()) must
55 * have names that begin with "dtrace_".
56 */
57
58 typedef enum dis_isize {
59 DIS_ISIZE_INSTR,
60 DIS_ISIZE_OPERAND
61 } dis_isize_t;
62
63
64 /*
65 * get a byte from instruction stream
66 */
67 static int
dtrace_dis_get_byte(void * p)68 dtrace_dis_get_byte(void *p)
69 {
70 int ret;
71 uchar_t **instr = p;
72
73 ret = **instr;
74 *instr += 1;
75
76 return (ret);
77 }
78
79 /*
80 * Returns either the size of a given instruction, in bytes, or the size of that
81 * instruction's memory access (if any), depending on the value of `which'.
82 * If a programming error in the tables is detected, the system will panic to
83 * ease diagnosis. Invalid instructions will not be flagged. They will appear
84 * to have an instruction size between 1 and the actual size, and will be
85 * reported as having no memory impact.
86 */
87 /* ARGSUSED2 */
88 static int
dtrace_dis_isize(uchar_t * instr,dis_isize_t which,model_t model,int * rmindex)89 dtrace_dis_isize(uchar_t *instr, dis_isize_t which, model_t model, int *rmindex)
90 {
91 int sz;
92 dis86_t x;
93 uint_t mode = SIZE32;
94
95 mode = (model == DATAMODEL_LP64) ? SIZE64 : SIZE32;
96
97 x.d86_data = (void **)&instr;
98 x.d86_get_byte = dtrace_dis_get_byte;
99 x.d86_check_func = NULL;
100
101 if (dtrace_disx86(&x, mode) != 0)
102 return (-1);
103
104 if (which == DIS_ISIZE_INSTR)
105 sz = x.d86_len; /* length of the instruction */
106 else
107 sz = x.d86_memsize; /* length of memory operand */
108
109 if (rmindex != NULL)
110 *rmindex = x.d86_rmindex;
111 return (sz);
112 }
113
114 int
dtrace_instr_size_isa(uchar_t * instr,model_t model,int * rmindex)115 dtrace_instr_size_isa(uchar_t *instr, model_t model, int *rmindex)
116 {
117 return (dtrace_dis_isize(instr, DIS_ISIZE_INSTR, model, rmindex));
118 }
119
120 int
dtrace_instr_size(uchar_t * instr)121 dtrace_instr_size(uchar_t *instr)
122 {
123 return (dtrace_dis_isize(instr, DIS_ISIZE_INSTR, DATAMODEL_NATIVE,
124 NULL));
125 }
126
127 /*ARGSUSED*/
128 int
instr_size(struct regs * rp,caddr_t * addrp,enum seg_rw rw)129 instr_size(struct regs *rp, caddr_t *addrp, enum seg_rw rw)
130 {
131 uchar_t instr[16]; /* maximum size instruction */
132 caddr_t pc = (caddr_t)rp->r_pc;
133
134 (void) copyin_nowatch(pc, (caddr_t)instr, sizeof (instr));
135
136 return (dtrace_dis_isize(instr,
137 rw == S_EXEC ? DIS_ISIZE_INSTR : DIS_ISIZE_OPERAND,
138 curproc->p_model, NULL));
139 }
140