obpsym.c revision 7799:05fc7b266484 
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 (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21
22/*
23 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
24 * Use is subject to license terms.
25 */
26
27/*
28 * This module supports callbacks from the firmware
29 * such that address and name lookups can work and use kernel symbol names.
30 * For example "ctrace" will provide symbolic names, if they are available.
31 * Also, normal firmware name to address lookups should work, though be
32 * careful with clashing kernel names, such as "startup" and "reset" which
33 * may be the firmware names and *not* the kernel names.
34 *
35 * The module locks the symbol tables in memory, when it's installed,
36 * and unlocks them when it is removed.  The module is loaded automatically
37 * on cobp systems and is replaced by forthdebug on all other systems.
38 *
39 * This file contains the actual code the does the lookups, and interfaces
40 * with the kernel kobj stuff.  The transfer of data and control to/from
41 * the firmware is handled in prom-dependent code.
42 */
43
44#include <sys/types.h>
45#include <sys/param.h>
46#include <sys/systm.h>
47#include <sys/debug.h>
48#include <sys/errno.h>
49#include <sys/modctl.h>
50#include <sys/kobj.h>
51#include <sys/promif.h>
52#include <sys/ddi.h>
53#include <sys/sunddi.h>
54#include <sys/reboot.h>
55#include <sys/callb.h>
56
57int obpsym_debug = 0;
58#define	DPRINTF(str)		if (obpsym_debug) prom_printf(str)
59#define	DPRINTF1(str, a)	if (obpsym_debug) prom_printf(str, a);
60#define	DPRINTF2(str, a, b)	if (obpsym_debug) prom_printf(str, a, b);
61#define	DXPRINTF		if (obpsym_debug > 1) prom_printf
62
63int obpheld = 1;		/* Prevents unloading when set */
64
65/*
66 * name_to_value - translate a string into an address
67 *
68 * The string may be one of two forms - 'symname' or 'modname:symname'.
69 * (We also accept 'unix:symname' as a synonymn for 'symname'.)
70 * The latter form causes a kobj_lookup() to occur only in the given module,
71 * the former causes a kobj_getsymvalue() on the entire kernel symbol table.
72 *
73 * mod_lock locking is not needed for the &modules list because
74 * modctl structures are never unlinked from the &modules list.
75 */
76int
77name_to_value(char *name, uintptr_t *value)
78{
79	register char *symname = name;
80	register char *modname = "";
81	char *p;
82	int retval = 0;
83	uintptr_t symvalue = 0;
84	char c = (char)0;
85
86	/*
87	 * we take names of the form: "modname:symbol", "unix:symbol", "symbol"
88	 */
89	if ((p = strchr(name, ':')) != NULL && p[1] != (char)0) {
90		symname = p + 1;
91		modname = name;
92		c = *p;
93		*p = (char)0;
94	}
95
96	if (*modname == (char)0) {
97		symvalue = kobj_getsymvalue(symname, 0);
98	} else  {
99		struct modctl *mp = &modules;
100
101		do {
102			if (strcmp(modname, mp->mod_modname) == 0) {
103				symvalue = kobj_lookup(mp->mod_mp, symname);
104				break;
105			}
106		} while ((mp = mp->mod_next) != &modules);
107	}
108
109	if (symvalue == 0)
110		retval = -1;
111	if (c != (char)0)		/* Restore incoming cstr */
112		*p = c;
113
114	*value = symvalue;
115	return (retval);
116}
117
118/*
119 * value_to_name - translate an address into a string + offset
120 *
121 * mod_lock locking is not needed fro the modules list because
122 * modctl structures are never unlinked from the &modules list.
123 */
124ulong_t
125value_to_name(uintptr_t value, char *symbol)
126{
127	struct modctl *modp = &modules;
128	ulong_t offset;
129	char *name;
130
131	DPRINTF1("value_to_name: Looking for %p\n", (void *)value);
132
133	do {
134		if (modp->mod_mp &&
135		    (name = kobj_searchsym(modp->mod_mp, value, &offset))) {
136			(void) strcpy(symbol, modp->mod_modname);
137			(void) strcat(symbol, ":");
138			(void) strcat(symbol, name);
139			return (offset);
140		}
141	} while ((modp = modp->mod_next) != &modules);
142
143	*symbol = (char)0;
144	return ((ulong_t)-1l);
145}
146
147/*
148 * loadable module wrapper
149 */
150static struct modlmisc modlmisc = {
151	&mod_miscops, "OBP symbol callbacks"
152};
153
154static struct modlinkage modlinkage = {
155	MODREV_1, (void *)&modlmisc, NULL
156};
157
158/*ARGSUSED*/
159static boolean_t
160reset_callbacks(void *arg, int code)
161{
162	extern void set_sym_callbacks();
163
164	if (code == CB_CODE_CPR_RESUME)
165		set_sym_callbacks();
166	return (B_TRUE);
167}
168
169int
170_init(void)
171{
172	int retval;
173	extern int install_callbacks(void);
174	extern void remove_callbacks(void);
175
176	if (install_callbacks() != 0)
177		return (ENXIO);
178
179	if (boothowto & RB_HALT)
180		debug_enter("obpsym: halt flag (-h) is set.\n");
181
182	retval = mod_install(&modlinkage);
183
184	/*
185	 * if load fails remove callback and unlock symbols
186	 */
187	if (retval) {
188		printf("obpsym: Error %d installing OBP syms module\n", retval);
189		remove_callbacks();
190	}
191	else
192		(void) callb_add(reset_callbacks, 0, CB_CL_CPR_OBP, "obpsym");
193
194	return (retval);
195}
196
197int
198_fini(void)
199{
200	int retval;
201	extern void remove_callbacks(void);
202
203	if (obpheld != 0)
204		return (EBUSY);
205
206	retval = mod_remove(&modlinkage);
207
208	/*
209	 * if unload succeeds remove callback and unlock symbols
210	 */
211	if (retval == 0) {
212		remove_callbacks();
213	}
214	return (retval);
215}
216
217int
218_info(struct modinfo *modinfop)
219{
220	return (mod_info(&modlinkage, modinfop));
221}
222