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#pragma ident	"%Z%%M%	%I%	%E% SMI"
28
29#include "misc.h"
30#include <ucontext.h>
31#include <sys/frame.h>
32#include <sys/stack.h>
33#include <stdio.h>
34
35#if defined(__sparc) || defined(__sparcv9)
36extern void flush_windows(void);
37#define	UMEM_FRAMESIZE	MINFRAME
38
39#elif defined(__i386) || defined(__amd64)
40/*
41 * On x86, MINFRAME is defined to be 0, but we want to be sure we can
42 * dereference the entire frame structure.
43 */
44#define	UMEM_FRAMESIZE	(sizeof (struct frame))
45
46#else
47#error needs update for new architecture
48#endif
49
50/*
51 * Get a pc-only stacktrace.  Used for kmem_alloc() buffer ownership tracking.
52 * Returns MIN(current stack depth, pcstack_limit).
53 */
54/*ARGSUSED*/
55int
56getpcstack(uintptr_t *pcstack, int pcstack_limit, int check_signal)
57{
58	struct frame *fp;
59	struct frame *nextfp, *minfp;
60	int depth = 0;
61	uintptr_t base = 0;
62	size_t size = 0;
63#ifndef UMEM_STANDALONE
64	int on_altstack = 0;
65	uintptr_t sigbase = 0;
66	size_t sigsize = 0;
67
68	stack_t st;
69
70	if (stack_getbounds(&st) != 0) {
71		if (thr_stksegment(&st) != 0 ||
72		    (uintptr_t)st.ss_sp < st.ss_size) {
73			return (0);		/* unable to get stack bounds */
74		}
75		/*
76		 * thr_stksegment(3C) has a slightly different interface than
77		 * stack_getbounds(3C) -- correct it
78		 */
79		st.ss_sp = (void *)(((uintptr_t)st.ss_sp) - st.ss_size);
80		st.ss_flags = 0;		/* can't be on-stack */
81	}
82	on_altstack = (st.ss_flags & SS_ONSTACK);
83
84	if (st.ss_size != 0) {
85		base = (uintptr_t)st.ss_sp;
86		size = st.ss_size;
87	} else {
88		/*
89		 * If size == 0, then ss_sp is the *top* of the stack.
90		 *
91		 * Since we only allow increasing frame pointers, and we
92		 * know our caller set his up correctly, we can treat ss_sp
93		 * as an upper bound safely.
94		 */
95		base = 0;
96		size = (uintptr_t)st.ss_sp;
97	}
98
99	if (check_signal != 0) {
100		void (*sigfunc)() = NULL;
101		int sigfuncsize = 0;
102		extern void thr_sighndlrinfo(void (**)(), int *);
103
104		thr_sighndlrinfo(&sigfunc, &sigfuncsize);
105		sigbase = (uintptr_t)sigfunc;
106		sigsize = sigfuncsize;
107	}
108#else /* UMEM_STANDALONE */
109	base = (uintptr_t)umem_min_stack;
110	size = umem_max_stack - umem_min_stack;
111#endif
112
113	/*
114	 * shorten size so that fr_savfp and fr_savpc will be within the stack
115	 * bounds.
116	 */
117	if (size >= UMEM_FRAMESIZE - 1)
118		size -= (UMEM_FRAMESIZE - 1);
119	else
120		size = 0;
121
122#if defined(__sparc) || defined(__sparcv9)
123	flush_windows();
124#endif
125
126	/* LINTED alignment */
127	fp = (struct frame *)((caddr_t)getfp() + STACK_BIAS);
128
129	minfp = fp;
130
131	if (((uintptr_t)fp - base) >= size)
132		return (0);	/* the frame pointer isn't in our stack */
133
134	while (depth < pcstack_limit) {
135		uintptr_t tmp;
136
137		/* LINTED alignment */
138		nextfp = (struct frame *)((caddr_t)fp->fr_savfp + STACK_BIAS);
139		tmp = (uintptr_t)nextfp;
140
141		/*
142		 * Check nextfp for validity.  It must be properly aligned,
143		 * increasing compared to the last %fp (or the top of the
144		 * stack we just switched to), and it must be inside
145		 * [base, base + size).
146		 */
147		if (tmp != SA(tmp))
148			break;
149		else if (nextfp <= minfp || (tmp - base) >= size) {
150#ifndef UMEM_STANDALONE
151			if (tmp == NULL || !on_altstack)
152				break;
153			/*
154			 * If we're on an alternate signal stack, try jumping
155			 * to the main thread stack.
156			 *
157			 * If the main thread stack has an unlimited size, we
158			 * punt, since we don't know where the frame pointer's
159			 * been.
160			 *
161			 * (thr_stksegment() returns the *top of stack*
162			 * in ss_sp, not the bottom)
163			 */
164			if (thr_stksegment(&st) == 0) {
165				if (st.ss_size >= (uintptr_t)st.ss_sp ||
166				    st.ss_size < UMEM_FRAMESIZE - 1)
167					break;
168
169				on_altstack = 0;
170				base = (uintptr_t)st.ss_sp - st.ss_size;
171				size = st.ss_size - (UMEM_FRAMESIZE - 1);
172				minfp = (struct frame *)base;
173				continue;		/* try again */
174			}
175#endif
176			break;
177		}
178
179#ifndef UMEM_STANDALONE
180		if (check_signal && (fp->fr_savpc - sigbase) <= sigsize)
181			umem_panic("called from signal handler");
182#endif
183		pcstack[depth++] = fp->fr_savpc;
184		fp = nextfp;
185		minfp = fp;
186	}
187	return (depth);
188}
189