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 #include <sys/vmem.h>
28 #include <sys/kmem.h>
29 #include <sys/param.h>
30 #include <sys/sysmacros.h>
31 #include <sys/cmn_err.h>
32 #include <vm/seg_kmem.h>
33
34 static vmem_t *id32_arena;
35 static kmem_cache_t *id32_cache;
36
37 #define ID32_BITS 5
38 #define ID32_ALIGN (1 << ID32_BITS)
39 #define ID32_MOD (ID32_ALIGN - 1)
40
41 #if defined(__amd64)
42 /*
43 * For amd64 the 32 bit id is the offset of the entry in the arena.
44 */
45 extern char *heap_core_base;
46 #define ID32_ENCODE(x) (((x) - (uintptr_t)heap_core_base) | \
47 ((((x) - (uintptr_t)heap_core_base) % ID32_MOD)) + 1)
48 #define ID32_DECODE(x) (P2ALIGN((x), (uintptr_t)ID32_ALIGN) + \
49 (uintptr_t)heap_core_base)
50 #define ID32_VALID(x) (ID32_ENCODE(ID32_DECODE(x)) == (x))
51 #else /* __amd64 */
52 /*
53 * All other architectures use the 32 bit pointer value for the 32 bit id.
54 */
55 #define ID32_ENCODE(x) (((x) | ((x) % ID32_MOD)) + 1)
56 #define ID32_DECODE(x) P2ALIGN((x), ID32_ALIGN)
57 #define ID32_VALID(x) (ID32_ENCODE(ID32_DECODE(x)) == (x))
58 #endif /* __amd64 */
59
60 void
id32_init(void)61 id32_init(void)
62 {
63 id32_arena = vmem_create("id32", NULL, 0, PAGESIZE,
64 segkmem_alloc, segkmem_free, heap32_arena, 0, VM_SLEEP);
65
66 id32_cache = kmem_cache_create("id32_cache", ID32_ALIGN, ID32_ALIGN,
67 NULL, NULL, NULL, NULL, id32_arena, 0);
68 }
69
70 /*
71 * Return a 32-bit identifier for the specified pointer.
72 */
73 uint32_t
id32_alloc(void * ptr,int kmflag)74 id32_alloc(void *ptr, int kmflag)
75 {
76 void **hent = kmem_cache_alloc(id32_cache, kmflag);
77 uintptr_t id;
78
79 if (hent == NULL)
80 return (0);
81
82 *hent = ptr;
83 id = ID32_ENCODE((uintptr_t)hent);
84 ASSERT64(id <= UINT32_MAX);
85 return ((uint32_t)id);
86 }
87
88 /*
89 * Free a 32-bit ID.
90 */
91 void
id32_free(uint32_t id)92 id32_free(uint32_t id)
93 {
94 if (!ID32_VALID(id)) {
95 cmn_err(CE_WARN, "id32_free(%x): bad ID rejected\n", id);
96 return;
97 }
98
99 kmem_cache_free(id32_cache, (void *)(uintptr_t)ID32_DECODE(id));
100 }
101
102 /*
103 * Return the pointer described by a 32-bit ID, or NULL if the ID is bad.
104 */
105 void *
id32_lookup(uint32_t id)106 id32_lookup(uint32_t id)
107 {
108 if (!ID32_VALID(id)) {
109 cmn_err(CE_WARN, "id32_lookup(%x): bad ID rejected\n", id);
110 return (NULL);
111 }
112
113 return (((void **)(uintptr_t)ID32_DECODE(id))[0]);
114 }
115