Annotation of sys/arch/zaurus/stand/zboot/alloc.c, Revision 1.1.1.1
1.1 nbrk 1: /* $OpenBSD: alloc.c,v 1.1 2005/01/10 00:25:03 deraadt Exp $ */
2: /* $NetBSD: alloc.c,v 1.6 1997/02/04 18:36:33 thorpej Exp $ */
3:
4: /*
5: * Copyright (c) 1997 Christopher G. Demetriou. All rights reserved.
6: * Copyright (c) 1996
7: * Matthias Drochner. All rights reserved.
8: * Copyright (c) 1993
9: * The Regents of the University of California. All rights reserved.
10: *
11: * This code is derived from software contributed to Berkeley by
12: * The Mach Operating System project at Carnegie-Mellon University.
13: *
14: * Redistribution and use in source and binary forms, with or without
15: * modification, are permitted provided that the following conditions
16: * are met:
17: * 1. Redistributions of source code must retain the above copyright
18: * notice, this list of conditions and the following disclaimer.
19: * 2. Redistributions in binary form must reproduce the above copyright
20: * notice, this list of conditions and the following disclaimer in the
21: * documentation and/or other materials provided with the distribution.
22: * 3. Neither the name of the University nor the names of its contributors
23: * may be used to endorse or promote products derived from this software
24: * without specific prior written permission.
25: *
26: * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29: * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36: * SUCH DAMAGE.
37: *
38: * @(#)alloc.c 8.1 (Berkeley) 6/11/93
39: *
40: *
41: * Copyright (c) 1989, 1990, 1991 Carnegie Mellon University
42: * All Rights Reserved.
43: *
44: * Author: Alessandro Forin
45: *
46: * Permission to use, copy, modify and distribute this software and its
47: * documentation is hereby granted, provided that both the copyright
48: * notice and this permission notice appear in all copies of the
49: * software, derivative works or modified versions, and any portions
50: * thereof, and that both notices appear in supporting documentation.
51: *
52: * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
53: * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
54: * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
55: *
56: * Carnegie Mellon requests users of this software to return to
57: *
58: * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
59: * School of Computer Science
60: * Carnegie Mellon University
61: * Pittsburgh PA 15213-3890
62: *
63: * any improvements or extensions that they make and grant Carnegie the
64: * rights to redistribute these changes.
65: */
66:
67: /*
68: * Dynamic memory allocator.
69: *
70: * Compile options:
71: *
72: * ALLOC_TRACE enable tracing of allocations/deallocations
73: *
74: * ALLOC_FIRST_FIT use a first-fit allocation algorithm, rather than
75: * the default best-fit algorithm.
76: *
77: * HEAP_LIMIT heap limit address (defaults to "no limit").
78: *
79: * HEAP_START start address of heap (defaults to '&end').
80: *
81: * DEBUG enable debugging sanity checks.
82: */
83:
84: #include <sys/param.h>
85:
86: /*
87: * Each block actually has ALIGN(unsigned) + ALIGN(size) bytes allocated
88: * to it, as follows:
89: *
90: * 0 ... (sizeof(unsigned) - 1)
91: * allocated or unallocated: holds size of user-data part of block.
92: *
93: * sizeof(unsigned) ... (ALIGN(sizeof(unsigned)) - 1)
94: * allocated: unused
95: * unallocated: depends on packing of struct fl
96: *
97: * ALIGN(sizeof(unsigned)) ... (ALIGN(sizeof(unsigned)) + ALIGN(data size) - 1)
98: * allocated: user data
99: * unallocated: depends on packing of struct fl
100: *
101: * 'next' is only used when the block is unallocated (i.e. on the free list).
102: * However, note that ALIGN(sizeof(unsigned)) + ALIGN(data size) must
103: * be at least 'sizeof(struct fl)', so that blocks can be used as structures
104: * when on the free list.
105: */
106:
107: #include <lib/libsa/stand.h>
108:
109: struct fl {
110: unsigned size;
111: struct fl *next;
112: } *freelist = (struct fl *)0;
113:
114: static char heap[4 * 1024 * 1024];
115: #define HEAP_START (heap)
116: #define HEAP_LIMIT (&heap[sizeof(heap)])
117:
118: #ifdef HEAP_START
119: static char *top = (char *)HEAP_START;
120: #else
121: extern char end[];
122: static char *top = end;
123: #endif
124:
125: void *
126: alloc(unsigned int size)
127: {
128: struct fl **f = &freelist, **bestf = NULL;
129: #ifndef ALLOC_FIRST_FIT
130: unsigned bestsize = 0xffffffff; /* greater than any real size */
131: #endif
132: char *help;
133: int failed;
134:
135: #ifdef ALLOC_TRACE
136: printf("alloc(%u)", size);
137: #endif
138:
139: #ifdef ALLOC_FIRST_FIT
140: while (*f != (struct fl *)0 && (*f)->size < size)
141: f = &((*f)->next);
142: bestf = f;
143: failed = (*bestf == (struct fl *)0);
144: #else
145: /* scan freelist */
146: while (*f) {
147: if ((*f)->size >= size) {
148: if ((*f)->size == size) /* exact match */
149: goto found;
150:
151: if ((*f)->size < bestsize) {
152: /* keep best fit */
153: bestf = f;
154: bestsize = (*f)->size;
155: }
156: }
157: f = &((*f)->next);
158: }
159:
160: /* no match in freelist if bestsize unchanged */
161: failed = (bestsize == 0xffffffff);
162: #endif
163:
164: if (failed) { /* nothing found */
165: /*
166: * allocate from heap, keep chunk len in
167: * first word
168: */
169: help = top;
170:
171: /* make _sure_ the region can hold a struct fl. */
172: if (size < ALIGN(sizeof (struct fl *)))
173: size = ALIGN(sizeof (struct fl *));
174: top += ALIGN(sizeof(unsigned)) + ALIGN(size);
175: #ifdef HEAP_LIMIT
176: if (top > (char *)HEAP_LIMIT)
177: panic("heap full (0x%lx+%u)", help, size);
178: #endif
179: *(unsigned *)help = ALIGN(size);
180: #ifdef ALLOC_TRACE
181: printf("=%p\n", help + ALIGN(sizeof(unsigned)));
182: #endif
183: return(help + ALIGN(sizeof(unsigned)));
184: }
185:
186: /* we take the best fit */
187: f = bestf;
188:
189: #ifndef ALLOC_FIRST_FIT
190: found:
191: #endif
192: /* remove from freelist */
193: help = (char *)*f;
194: *f = (*f)->next;
195: #ifdef ALLOC_TRACE
196: printf("=%p (origsize %u)\n", help + ALIGN(sizeof(unsigned)),
197: *(unsigned *)help);
198: #endif
199: return(help + ALIGN(sizeof(unsigned)));
200: }
201:
202: void
203: free(void *ptr, unsigned int size)
204: {
205: struct fl *f = (struct fl *)((char *)ptr -
206: ALIGN(sizeof(unsigned)));
207:
208: #ifdef ALLOC_TRACE
209: printf("free(%p, %u) (origsize %u)\n", ptr, size, f->size);
210: #endif
211: #ifdef DEBUG
212: if (size > f->size)
213: printf("free %u bytes @%p, should be <=%u\n",
214: size, ptr, f->size);
215: #ifdef HEAP_START
216: if (ptr < (void *)HEAP_START)
217: #else
218: if (ptr < (void *)end)
219: #endif
220: printf("free: %lx before start of heap.\n", (u_long)ptr);
221:
222: #ifdef HEAP_LIMIT
223: if (ptr > (void *)HEAP_LIMIT)
224: printf("free: %lx beyond end of heap.\n", (u_long)ptr);
225: #endif
226: #endif /* DEBUG */
227: /* put into freelist */
228: f->next = freelist;
229: freelist = f;
230: }
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