1/*
2 * Copyright (c) 2000-2004 Apple Computer, Inc. All rights reserved.
3 *
4 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
5 *
6 * This file contains Original Code and/or Modifications of Original Code
7 * as defined in and that are subject to the Apple Public Source License
8 * Version 2.0 (the 'License'). You may not use this file except in
9 * compliance with the License. The rights granted to you under the License
10 * may not be used to create, or enable the creation or redistribution of,
11 * unlawful or unlicensed copies of an Apple operating system, or to
12 * circumvent, violate, or enable the circumvention or violation of, any
13 * terms of an Apple operating system software license agreement.
14 *
15 * Please obtain a copy of the License at
16 * http://www.opensource.apple.com/apsl/ and read it before using this file.
17 *
18 * The Original Code and all software distributed under the License are
19 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
20 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
21 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
22 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
23 * Please see the License for the specific language governing rights and
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25 *
26 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
27 */
28/*
29 * @OSF_COPYRIGHT@
30 */
31/*
32 * Mach Operating System
33 * Copyright (c) 1991,1990,1989 Carnegie Mellon University
34 * All Rights Reserved.
35 *
36 * Permission to use, copy, modify and distribute this software and its
37 * documentation is hereby granted, provided that both the copyright
38 * notice and this permission notice appear in all copies of the
39 * software, derivative works or modified versions, and any portions
40 * thereof, and that both notices appear in supporting documentation.
41 *
42 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
43 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
44 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
45 *
46 * Carnegie Mellon requests users of this software to return to
47 *
48 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
49 * School of Computer Science
50 * Carnegie Mellon University
51 * Pittsburgh PA 15213-3890
52 *
53 * any improvements or extensions that they make and grant Carnegie Mellon
54 * the rights to redistribute these changes.
55 */
56/*
57 */
58/*
59 * File: ipc/ipc_entry.h
60 * Author: Rich Draves
61 * Date: 1989
62 *
63 * Definitions for translation entries, which represent
64 * tasks' capabilities for ports and port sets.
65 */
66
67#ifndef _IPC_IPC_ENTRY_H_
68#define _IPC_IPC_ENTRY_H_
69
70#include <mach/mach_types.h>
71#include <mach/port.h>
72#include <mach/kern_return.h>
73
74#include <kern/kern_types.h>
75#include <kern/kalloc.h>
76#include <kern/smr_types.h>
77
78#include <ipc/ipc_types.h>
79
80/*
81 * Spaces hold capabilities for ipc_object_t's.
82 * Each ipc_entry_t records a capability. Most capabilities have
83 * small names, and the entries are elements of a table.
84 *
85 * The ie_index field of entries in the table implements
86 * a ordered hash table with open addressing and linear probing.
87 *
88 * The ie_dist field holds the distance to the desired spot,
89 * which is used to implement robin-hood hashing.
90 *
91 * This hash table converts (space, object) -> name.
92 * It is used independently of the other fields.
93 *
94 * Free (unallocated) entries in the table have null ie_object
95 * fields. The ie_bits field is zero except for IE_BITS_GEN.
96 * The ie_next (ie_request) field links free entries into a free list.
97 *
98 * The first entry in the table (index 0) is always free.
99 * It is used as the head of the free list.
100 */
101
102#define IPC_ENTRY_DIST_BITS 12
103#define IPC_ENTRY_DIST_MAX ((1 << IPC_ENTRY_DIST_BITS) - 1)
104#define IPC_ENTRY_INDEX_BITS 32
105#define IPC_ENTRY_INDEX_MAX (UINT32_MAX)
106
107struct ipc_entry {
108 union {
109 struct ipc_object *XNU_PTRAUTH_SIGNED_PTR("ipc_entry.ie_object") ie_object;
110 struct ipc_object *XNU_PTRAUTH_SIGNED_PTR("ipc_entry.ie_object") volatile ie_volatile_object;
111 struct ipc_entry_table *XNU_PTRAUTH_SIGNED_PTR("ipc_entry.ie_self") ie_self;
112 };
113 union {
114 struct {
115 ipc_entry_bits_t ie_bits;
116 union {
117 mach_port_index_t ie_next; /* next in freelist, or... */
118 ipc_table_index_t ie_request; /* dead name request notify */
119 };
120
121 /* hash fields */
122 uint32_t ie_dist;
123 mach_port_index_t ie_index;
124 };
125 struct smr_node ie_smr_node;
126 };
127};
128
129#define IPC_ENTRY_TABLE_MIN 32
130#define IPC_ENTRY_TABLE_PERIOD 16
131KALLOC_ARRAY_TYPE_DECL(ipc_entry_table, struct ipc_entry);
132
133#define IE_REQ_NONE 0 /* no request */
134
135#define IE_BITS_UREFS_MASK 0x0000ffff /* 16 bits of user-reference */
136#define IE_BITS_UREFS(bits) ((bits) & IE_BITS_UREFS_MASK)
137
138#define IE_BITS_TYPE_MASK 0x001f0000 /* 5 bits of capability type */
139#define IE_BITS_TYPE(bits) ((bits) & IE_BITS_TYPE_MASK)
140
141#define IE_BITS_EXTYPE_MASK 0x00200000 /* 1 bit for extended capability */
142
143#ifndef NO_PORT_GEN
144#define IE_BITS_GEN_MASK 0xff000000 /* 8 bits for generation */
145#define IE_BITS_GEN(bits) ((bits) & IE_BITS_GEN_MASK)
146#define IE_BITS_GEN_ONE 0x04000000 /* low bit of generation */
147#define IE_BITS_ROLL_POS 22 /* LSB pos of generation rollover */
148#define IE_BITS_ROLL_BITS 2 /* number of generation rollover bits */
149#define IE_BITS_ROLL_MASK (((1 << IE_BITS_ROLL_BITS) - 1) << IE_BITS_ROLL_POS)
150#define IE_BITS_ROLL(bits) ((((bits) & IE_BITS_ROLL_MASK) << 8) ^ IE_BITS_GEN_MASK)
151
152/*
153 * Restart a generation counter with the specified bits for the rollover point.
154 * There are 4 different rollover points:
155 * bits rollover period
156 * 0 0 64
157 * 0 1 48
158 * 1 0 32
159 * 1 1 16
160 */
161static inline ipc_entry_bits_t
162ipc_entry_new_rollpoint(
163 ipc_entry_bits_t rollbits)
164{
165 rollbits = (rollbits << IE_BITS_ROLL_POS) & IE_BITS_ROLL_MASK;
166 ipc_entry_bits_t newgen = IE_BITS_GEN_MASK + IE_BITS_GEN_ONE;
167 return newgen | rollbits;
168}
169
170/*
171 * Get the next gencount, modulo the entry's rollover point. If the sum rolls over,
172 * the caller should re-start the generation counter with a different rollpoint.
173 */
174static inline ipc_entry_bits_t
175ipc_entry_new_gen(
176 ipc_entry_bits_t oldgen)
177{
178 ipc_entry_bits_t sum = (oldgen + IE_BITS_GEN_ONE) & IE_BITS_GEN_MASK;
179 ipc_entry_bits_t roll = oldgen & IE_BITS_ROLL_MASK;
180 ipc_entry_bits_t newgen = (sum % IE_BITS_ROLL(oldgen)) | roll;
181 return newgen;
182}
183
184/* Determine if a gencount has rolled over or not. */
185static inline boolean_t
186ipc_entry_gen_rolled(
187 ipc_entry_bits_t oldgen,
188 ipc_entry_bits_t newgen)
189{
190 return (oldgen & IE_BITS_GEN_MASK) > (newgen & IE_BITS_GEN_MASK);
191}
192
193#else
194#define IE_BITS_GEN_MASK 0
195#define IE_BITS_GEN(bits) 0
196#define IE_BITS_GEN_ONE 0
197#define IE_BITS_ROLL_POS 0
198#define IE_BITS_ROLL_MASK 0
199#define IE_BITS_ROLL(bits) (bits)
200
201static inline ipc_entry_bits_t
202ipc_entry_new_rollpoint(
203 ipc_entry_bits_t rollbits)
204{
205 return 0;
206}
207
208static inline ipc_entry_bits_t
209ipc_entry_new_gen(
210 ipc_entry_bits_t oldgen)
211{
212 return 0;
213}
214
215static inline boolean_t
216ipc_entry_gen_rolled(
217 ipc_entry_bits_t oldgen,
218 ipc_entry_bits_t newgen)
219{
220 return FALSE;
221}
222
223#endif /* !USE_PORT_GEN */
224
225#define IE_BITS_RIGHT_MASK 0x007fffff /* relevant to the right */
226/*
227 * Exported interfaces
228 */
229
230extern unsigned int ipc_entry_table_count_max(void) __pure2;
231
232/* Search for entry in a space by name */
233extern ipc_entry_t ipc_entry_lookup(
234 ipc_space_t space,
235 mach_port_name_t name);
236
237/* Hold a number of entries in a locked space */
238extern kern_return_t ipc_entries_hold(
239 ipc_space_t space,
240 natural_t count);
241
242/* claim and initialize a held entry in a locked space */
243extern kern_return_t ipc_entry_claim(
244 ipc_space_t space,
245 ipc_object_t object,
246 mach_port_name_t *namep,
247 ipc_entry_t *entryp);
248
249/* Allocate an entry in a space, growing the space if necessary */
250extern kern_return_t ipc_entry_alloc(
251 ipc_space_t space,
252 ipc_object_t object,
253 mach_port_name_t *namep,
254 ipc_entry_t *entryp);
255
256/* Allocate/find an entry in a space with a specific name */
257extern kern_return_t ipc_entry_alloc_name(
258 ipc_space_t space,
259 mach_port_name_t name,
260 ipc_entry_t *entryp);
261
262/* Deallocate an entry from a space */
263extern void ipc_entry_dealloc(
264 ipc_space_t space,
265 ipc_object_t object,
266 mach_port_name_t name,
267 ipc_entry_t entry);
268
269/* Mark and entry modified in a space */
270extern void ipc_entry_modified(
271 ipc_space_t space,
272 mach_port_name_t name,
273 ipc_entry_t entry);
274
275/* Grow the table in a space */
276extern kern_return_t ipc_entry_grow_table(
277 ipc_space_t space,
278 ipc_table_elems_t target_size);
279
280/* mask on/off default entry generation bits */
281extern mach_port_name_t ipc_entry_name_mask(
282 mach_port_name_t name);
283#endif /* _IPC_IPC_ENTRY_H_ */
284