1/*-
2 * Copyright (c) 2005 Antoine Brodin
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27#include "opt_ddb.h"
28
29#include <sys/cdefs.h>
30__FBSDID("$FreeBSD$");
31
32#include <sys/param.h>
33#include <sys/kernel.h>
34#ifdef KTR
35#include <sys/ktr.h>
36#endif
37#include <sys/linker.h>
38#include <sys/malloc.h>
39#include <sys/sbuf.h>
40#include <sys/stack.h>
41#include <sys/systm.h>
42#include <sys/sysctl.h>
43
44FEATURE(stack, "Support for capturing kernel stack");
45
46static MALLOC_DEFINE(M_STACK, "stack", "Stack Traces");
47
48static int stack_symbol(vm_offset_t pc, char *namebuf, u_int buflen,
49	    long *offset);
50static int stack_symbol_ddb(vm_offset_t pc, const char **name, long *offset);
51
52struct stack *
53stack_create(void)
54{
55	struct stack *st;
56
57	st = malloc(sizeof *st, M_STACK, M_WAITOK | M_ZERO);
58	return (st);
59}
60
61void
62stack_destroy(struct stack *st)
63{
64
65	free(st, M_STACK);
66}
67
68int
69stack_put(struct stack *st, vm_offset_t pc)
70{
71
72	if (st->depth < STACK_MAX) {
73		st->pcs[st->depth++] = pc;
74		return (0);
75	} else
76		return (-1);
77}
78
79void
80stack_copy(const struct stack *src, struct stack *dst)
81{
82
83	*dst = *src;
84}
85
86void
87stack_zero(struct stack *st)
88{
89
90	bzero(st, sizeof *st);
91}
92
93void
94stack_print(const struct stack *st)
95{
96	char namebuf[64];
97	long offset;
98	int i;
99
100	KASSERT(st->depth <= STACK_MAX, ("bogus stack"));
101	for (i = 0; i < st->depth; i++) {
102		(void)stack_symbol(st->pcs[i], namebuf, sizeof(namebuf),
103		    &offset);
104		printf("#%d %p at %s+%#lx\n", i, (void *)st->pcs[i],
105		    namebuf, offset);
106	}
107}
108
109void
110stack_print_short(const struct stack *st)
111{
112	char namebuf[64];
113	long offset;
114	int i;
115
116	KASSERT(st->depth <= STACK_MAX, ("bogus stack"));
117	for (i = 0; i < st->depth; i++) {
118		if (i > 0)
119			printf(" ");
120		if (stack_symbol(st->pcs[i], namebuf, sizeof(namebuf),
121		    &offset) == 0)
122			printf("%s+%#lx", namebuf, offset);
123		else
124			printf("%p", (void *)st->pcs[i]);
125	}
126	printf("\n");
127}
128
129void
130stack_print_ddb(const struct stack *st)
131{
132	const char *name;
133	long offset;
134	int i;
135
136	KASSERT(st->depth <= STACK_MAX, ("bogus stack"));
137	for (i = 0; i < st->depth; i++) {
138		stack_symbol_ddb(st->pcs[i], &name, &offset);
139		printf("#%d %p at %s+%#lx\n", i, (void *)st->pcs[i],
140		    name, offset);
141	}
142}
143
144#if defined(DDB) || defined(WITNESS)
145void
146stack_print_short_ddb(const struct stack *st)
147{
148	const char *name;
149	long offset;
150	int i;
151
152	KASSERT(st->depth <= STACK_MAX, ("bogus stack"));
153	for (i = 0; i < st->depth; i++) {
154		if (i > 0)
155			printf(" ");
156		if (stack_symbol_ddb(st->pcs[i], &name, &offset) == 0)
157			printf("%s+%#lx", name, offset);
158		else
159			printf("%p", (void *)st->pcs[i]);
160	}
161	printf("\n");
162}
163#endif
164
165/*
166 * Two print routines -- one for use from DDB and DDB-like contexts, the
167 * other for use in the live kernel.
168 */
169void
170stack_sbuf_print(struct sbuf *sb, const struct stack *st)
171{
172	char namebuf[64];
173	long offset;
174	int i;
175
176	KASSERT(st->depth <= STACK_MAX, ("bogus stack"));
177	for (i = 0; i < st->depth; i++) {
178		(void)stack_symbol(st->pcs[i], namebuf, sizeof(namebuf),
179		    &offset);
180		sbuf_printf(sb, "#%d %p at %s+%#lx\n", i, (void *)st->pcs[i],
181		    namebuf, offset);
182	}
183}
184
185#if defined(DDB) || defined(WITNESS)
186void
187stack_sbuf_print_ddb(struct sbuf *sb, const struct stack *st)
188{
189	const char *name;
190	long offset;
191	int i;
192
193	KASSERT(st->depth <= STACK_MAX, ("bogus stack"));
194	for (i = 0; i < st->depth; i++) {
195		(void)stack_symbol_ddb(st->pcs[i], &name, &offset);
196		sbuf_printf(sb, "#%d %p at %s+%#lx\n", i, (void *)st->pcs[i],
197		    name, offset);
198	}
199}
200#endif
201
202#ifdef KTR
203void
204stack_ktr(u_int mask, const char *file, int line, const struct stack *st,
205    u_int depth, int cheap)
206{
207#ifdef DDB
208	const char *name;
209	long offset;
210	int i;
211#endif
212
213	KASSERT(st->depth <= STACK_MAX, ("bogus stack"));
214	if (cheap) {
215		ktr_tracepoint(mask, file, line, "#0 %p %p %p %p %p %p",
216		    st->pcs[0], st->pcs[1], st->pcs[2], st->pcs[3],
217		    st->pcs[4], st->pcs[5]);
218		if (st->depth <= 6)
219			return;
220		ktr_tracepoint(mask, file, line, "#1 %p %p %p %p %p %p",
221		    st->pcs[6], st->pcs[7], st->pcs[8], st->pcs[9],
222		    st->pcs[10], st->pcs[11]);
223		if (st->depth <= 12)
224			return;
225		ktr_tracepoint(mask, file, line, "#2 %p %p %p %p %p %p",
226		    st->pcs[12], st->pcs[13], st->pcs[14], st->pcs[15],
227		    st->pcs[16], st->pcs[17]);
228#ifdef DDB
229	} else {
230		if (depth == 0 || st->depth < depth)
231			depth = st->depth;
232		for (i = 0; i < depth; i++) {
233			(void)stack_symbol_ddb(st->pcs[i], &name, &offset);
234			ktr_tracepoint(mask, file, line, "#%d %p at %s+%#lx",
235			    i, st->pcs[i], (u_long)name, offset, 0, 0);
236		}
237#endif
238	}
239}
240#endif
241
242/*
243 * Two variants of stack symbol lookup -- one that uses the DDB interfaces
244 * and bypasses linker locking, and the other that doesn't.
245 */
246static int
247stack_symbol(vm_offset_t pc, char *namebuf, u_int buflen, long *offset)
248{
249
250	if (linker_search_symbol_name((caddr_t)pc, namebuf, buflen,
251	    offset) != 0) {
252		*offset = 0;
253		strlcpy(namebuf, "??", buflen);
254		return (ENOENT);
255	} else
256		return (0);
257}
258
259static int
260stack_symbol_ddb(vm_offset_t pc, const char **name, long *offset)
261{
262	linker_symval_t symval;
263	c_linker_sym_t sym;
264
265	if (linker_ddb_search_symbol((caddr_t)pc, &sym, offset) != 0)
266		goto out;
267	if (linker_ddb_symbol_values(sym, &symval) != 0)
268		goto out;
269	if (symval.name != NULL) {
270		*name = symval.name;
271		return (0);
272	}
273 out:
274	*offset = 0;
275	*name = "??";
276	return (ENOENT);
277}
278