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