xref: /titanic_44/usr/src/uts/common/krtld/kobj_kdi.c (revision 18c2aff776a775d34a4c9893a4c72e0434d68e36)
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 2004 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 #pragma ident	"%Z%%M%	%I%	%E% SMI"
28 
29 /*
30  * The KDI is used to allow the kernel debugger to directly invoke various
31  * kernel functions.  In some cases, such as with kdi_mod_iter(), the
32  * debugger needs to execute functions that use the kernel's linker bindings.
33  * In other cases, the implementation of the KDI functions vary by platform
34  * and/or by CPU.  By embedding the implementation of these functions in
35  * the platmod/cpumod, we can avoid the need for platform-specific knowledge
36  * in the debugger, and can thus have a single debugger binary for all
37  * platforms.
38  *
39  * There are three classes of KDI function:
40  *
41  * 1. Normal - These are functions whose implementations are in the kernel for
42  *    convenience.  An example is the modctl iterator, kdi_mod_iter.  Using the
43  *    modules symbol, this function iterates through the kernel's modctl list,
44  *    invoking a debugger-provided callback for each one.  This function is in
45  *    the KDI because the debugger needs to be able to execute it in order to
46  *    enable symbol resolution.  Without symbol resolution, the debugger can't
47  *    locate the modules symbol.  A chicken-and-egg problem results.  We solve
48  *    this problem by locating the module iterator in the kernel, where run-time
49  *    linking solves the problem for us.
50  *
51  * 2. CPU-specific - Functions in this class have implementations that differ
52  *    by CPU.  For example, the crosscall delivery notification method differs
53  *    between Cheetah and Jalapeno, necessitating a different implementation for
54  *    each.  By locating the KDI implementation of these functions in the
55  *    cpumods, we automatically get the correct implementation, as krtld
56  *    automatically loads the correct cpumod when it starts.  The cpumods
57  *    directly fill in their portion of the kdi_t, using the mandatory
58  *    cpu_kdi_init cpumod entry point.
59  *
60  * 3. Platform-specific - Similar to the CPU-specific class, platform-specific
61  *    KDI functions have implementations that differ from platform to platform.
62  *    As such, the implementations live in the platmods.  Further
63  *    differentiating the platform-specific KDI functions from their
64  *    CPU-dependent brethren, many directly invoke PROM functions.  This poses
65  *    a problem, as the platmods use the kernel's promif functions, rather than
66  *    the lock-free kmdb versions.  We provide an interposition layer for these
67  *    platform-specific calls that disables the pre- and post-processing
68  *    functions used by the kernel to implement kernel-specific functionality
69  *    that must not be executed when kmdb has control of the machine.  Platmods
70  *    fill in a kdi_plat_t using their optional plat_kdi_init entry point.
71  *    krtld provides wrapper functions which suspend the necessary functions in
72  *    the promif layer before invoking the kdi_plat_t functions (if any).
73  */
74 
75 #include <sys/types.h>
76 #include <sys/systm.h>
77 #include <sys/reboot.h>
78 #include <sys/kdi_impl.h>
79 
80 #include <kobj_kdi.h>
81 
82 #define	KOBJ_KDI_MOD_IDLE	0
83 #define	KOBJ_KDI_MOD_CHANGING	1
84 #define	KOBJ_KDI_MOD_CHANGED	2
85 
86 static int kobj_kdi_mod_state = KOBJ_KDI_MOD_IDLE;
87 
88 extern int standalone;
89 
90 cons_polledio_t *
91 kobj_kdi_get_polled_io(void)
92 {
93 	cons_polledio_t **polled_io = &cons_polledio;
94 
95 	return (polled_io == NULL ? NULL : *polled_io);
96 }
97 
98 int
99 kobj_kdi_mod_iter(int (*func)(struct modctl *, void *), void *arg)
100 {
101 	int rc;
102 
103 	if (standalone) {
104 		struct modctl_list *lp, **lpp;
105 
106 		for (lpp = kobj_linkmaps; *lpp != NULL; lpp++) {
107 			for (lp = *lpp; lp != NULL; lp = lp->modl_next) {
108 				if ((rc = func(lp->modl_modp, arg)) != 0)
109 					return (rc);
110 			}
111 		}
112 
113 	} else {
114 		struct modctl *modp = &modules;
115 
116 		do {
117 			if ((rc = func(modp, arg)) != 0)
118 				return (rc);
119 		} while ((modp = modp->mod_next) != &modules);
120 	}
121 
122 	return (0);
123 }
124 
125 int
126 kobj_kdi_mod_isloaded(struct modctl *modp)
127 {
128 	return (modp->mod_mp != NULL);
129 }
130 
131 int
132 kobj_kdi_mods_changed(void)
133 {
134 	int state;
135 
136 	if ((state = kobj_kdi_mod_state) == KOBJ_KDI_MOD_CHANGED)
137 		kobj_kdi_mod_state = KOBJ_KDI_MOD_IDLE;
138 
139 	return (state != KOBJ_KDI_MOD_IDLE);
140 }
141 
142 /*ARGSUSED1*/
143 void
144 kobj_kdi_mod_notify(uint_t why, struct modctl *what)
145 {
146 	switch (why) {
147 	case KOBJ_NOTIFY_MODLOADING:
148 		kobj_kdi_mod_state = KOBJ_KDI_MOD_CHANGING;
149 		break;
150 	case KOBJ_NOTIFY_MODLOADED:
151 		kobj_kdi_mod_state = KOBJ_KDI_MOD_CHANGED;
152 		if (boothowto & RB_DEBUG)
153 			kdi_dvec_mod_loaded(what);
154 		break;
155 	case KOBJ_NOTIFY_MODUNLOADING:
156 		kobj_kdi_mod_state = KOBJ_KDI_MOD_CHANGING;
157 		if (boothowto & RB_DEBUG)
158 			kdi_dvec_mod_unloading(what);
159 		break;
160 	case KOBJ_NOTIFY_MODUNLOADED:
161 		kobj_kdi_mod_state = KOBJ_KDI_MOD_CHANGED;
162 		break;
163 	}
164 }
165 
166 /*
167  * Compare two modctl and module snapshots, attempting to determine whether
168  * the module to which they both refer has changed between the time of the first
169  * and the time of the second.  We can't do a straight bcmp, because there are
170  * fields that change in the normal course of operations.  False positives
171  * aren't the end of the world, but it'd be nice to avoid flagging a module
172  * as changed every time someone holds or releases it.
173  */
174 int
175 kobj_kdi_mod_haschanged(struct modctl *mc1, struct module *mp1,
176     struct modctl *mc2, struct module *mp2)
177 {
178 	if (mc1->mod_loadcnt != mc2->mod_loadcnt || mc1->mod_mp != mc2->mod_mp)
179 		return (1);
180 
181 	if (mc1->mod_mp == NULL)
182 		return (0);
183 
184 	/* Take breath here. */
185 	return (bcmp(&mp1->hdr, &mp2->hdr, sizeof (mp1->hdr)) != 0 ||
186 	    mp1->symhdr != mp2->symhdr || mp1->strhdr != mp2->strhdr ||
187 	    mp1->text != mp2->text || mp1->bss != mp2->bss ||
188 	    mp1->ctfdata != mp2->ctfdata || mp1->ctfsize != mp2->ctfsize);
189 }
190 
191 void
192 kobj_kdi_system_claim(void)
193 {
194 	kobj_kdi.kdi_plat_call(kobj_kdi.pkdi_system_claim);
195 	kobj_kdi.kdi_plat_call(kobj_kdi.pkdi_console_claim);
196 }
197 
198 void
199 kobj_kdi_system_release(void)
200 {
201 	kobj_kdi.kdi_plat_call(kobj_kdi.pkdi_console_release);
202 	kobj_kdi.kdi_plat_call(kobj_kdi.pkdi_system_release);
203 }
204 
205 void
206 kobj_kdi_init(void)
207 {
208 	static const char *const initializers[] = {
209 		"cpu_kdi_init", "mach_kdi_init", "plat_kdi_init", NULL
210 	};
211 
212 	Sym *sym;
213 	int i;
214 
215 	for (i = 0; initializers[i] != NULL; i++) {
216 		if ((sym = kobj_lookup_kernel(initializers[i])) != NULL)
217 			((void (*)(kdi_t *))sym->st_value)(&kobj_kdi);
218 	}
219 }
220 
221 kdi_t kobj_kdi = {
222 	KDI_VERSION,
223 	kobj_kdi_mods_changed,
224 	kobj_kdi_mod_iter,
225 	kobj_kdi_mod_isloaded,
226 	kobj_kdi_mod_haschanged,
227 	kobj_kdi_system_claim,
228 	kobj_kdi_system_release,
229 	kdi_pread,
230 	kdi_pwrite,
231 	kdi_flush_caches,
232 	kdi_range_is_nontoxic,
233 	kobj_kdi_get_polled_io,
234 	kdi_vtop,
235 	kdi_dtrace_get_state,
236 	kdi_dtrace_set,
237 	/*
238 	 * The rest are filled in by cpu_kdi_init, mach_kdi_init, and/or
239 	 * plat_kdi_init.
240 	 */
241 	NULL,			/* kdi_plat_call */
242 	{ NULL },		/* kdi_arch */
243 	{ NULL }		/* kdi_plat */
244 };
245