FreeBSD/Linux Kernel Cross Reference
sys/sys/param.h
1 /*-
2 * Copyright (c) 1982, 1986, 1989, 1993
3 * The Regents of the University of California. All rights reserved.
4 * (c) UNIX System Laboratories, Inc.
5 * All or some portions of this file are derived from material licensed
6 * to the University of California by American Telephone and Telegraph
7 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
8 * the permission of UNIX System Laboratories, Inc.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 4. Neither the name of the University nor the names of its contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 *
34 * @(#)param.h 8.3 (Berkeley) 4/4/95
35 * $FreeBSD: releng/11.2/sys/sys/param.h 334459 2018-06-01 00:22:49Z gjb $
36 */
37
38 #ifndef _SYS_PARAM_H_
39 #define _SYS_PARAM_H_
40
41 #include <sys/_null.h>
42
43 #define BSD 199506 /* System version (year & month). */
44 #define BSD4_3 1
45 #define BSD4_4 1
46
47 /*
48 * __FreeBSD_version numbers are documented in the Porter's Handbook.
49 * If you bump the version for any reason, you should update the documentation
50 * there.
51 * Currently this lives here in the doc/ repository:
52 *
53 * head/en_US.ISO8859-1/books/porters-handbook/versions/chapter.xml
54 *
55 * scheme is: <major><two digit minor>Rxx
56 * 'R' is in the range 0 to 4 if this is a release branch or
57 * X.0-CURRENT before releng/X.0 is created, otherwise 'R' is
58 * in the range 5 to 9.
59 */
60 #undef __FreeBSD_version
61 #define __FreeBSD_version 1102000 /* Master, propagated to newvers */
62
63 /*
64 * __FreeBSD_kernel__ indicates that this system uses the kernel of FreeBSD,
65 * which by definition is always true on FreeBSD. This macro is also defined
66 * on other systems that use the kernel of FreeBSD, such as GNU/kFreeBSD.
67 *
68 * It is tempting to use this macro in userland code when we want to enable
69 * kernel-specific routines, and in fact it's fine to do this in code that
70 * is part of FreeBSD itself. However, be aware that as presence of this
71 * macro is still not widespread (e.g. older FreeBSD versions, 3rd party
72 * compilers, etc), it is STRONGLY DISCOURAGED to check for this macro in
73 * external applications without also checking for __FreeBSD__ as an
74 * alternative.
75 */
76 #undef __FreeBSD_kernel__
77 #define __FreeBSD_kernel__
78
79 #if defined(_KERNEL) || defined(IN_RTLD)
80 #define P_OSREL_SIGWAIT 700000
81 #define P_OSREL_SIGSEGV 700004
82 #define P_OSREL_MAP_ANON 800104
83 #define P_OSREL_MAP_FSTRICT 1100036
84 #define P_OSREL_SHUTDOWN_ENOTCONN 1100077
85 #define P_OSREL_MAP_GUARD 1200035
86 #define P_OSREL_MAP_GUARD_11 1101501
87 #define P_OSREL_WRFSBASE 1200041
88 #define P_OSREL_WRFSBASE_11 1101503
89
90 #define P_OSREL_MAJOR(x) ((x) / 100000)
91 #endif
92
93 #ifndef LOCORE
94 #include <sys/types.h>
95 #endif
96
97 /*
98 * Machine-independent constants (some used in following include files).
99 * Redefined constants are from POSIX 1003.1 limits file.
100 *
101 * MAXCOMLEN should be >= sizeof(ac_comm) (see <acct.h>)
102 */
103 #include <sys/syslimits.h>
104
105 #define MAXCOMLEN 19 /* max command name remembered */
106 #define MAXINTERP PATH_MAX /* max interpreter file name length */
107 #define MAXLOGNAME 33 /* max login name length (incl. NUL) */
108 #define MAXUPRC CHILD_MAX /* max simultaneous processes */
109 #define NCARGS ARG_MAX /* max bytes for an exec function */
110 #define NGROUPS (NGROUPS_MAX+1) /* max number groups */
111 #define NOFILE OPEN_MAX /* max open files per process */
112 #define NOGROUP 65535 /* marker for empty group set member */
113 #define MAXHOSTNAMELEN 256 /* max hostname size */
114 #define SPECNAMELEN 63 /* max length of devicename */
115
116 /* More types and definitions used throughout the kernel. */
117 #ifdef _KERNEL
118 #include <sys/cdefs.h>
119 #include <sys/errno.h>
120 #ifndef LOCORE
121 #include <sys/time.h>
122 #include <sys/priority.h>
123 #endif
124
125 #ifndef FALSE
126 #define FALSE 0
127 #endif
128 #ifndef TRUE
129 #define TRUE 1
130 #endif
131 #endif
132
133 #ifndef _KERNEL
134 /* Signals. */
135 #include <sys/signal.h>
136 #endif
137
138 /* Machine type dependent parameters. */
139 #include <machine/param.h>
140 #ifndef _KERNEL
141 #include <sys/limits.h>
142 #endif
143
144 #ifndef DEV_BSHIFT
145 #define DEV_BSHIFT 9 /* log2(DEV_BSIZE) */
146 #endif
147 #define DEV_BSIZE (1<<DEV_BSHIFT)
148
149 #ifndef BLKDEV_IOSIZE
150 #define BLKDEV_IOSIZE PAGE_SIZE /* default block device I/O size */
151 #endif
152 #ifndef DFLTPHYS
153 #define DFLTPHYS (64 * 1024) /* default max raw I/O transfer size */
154 #endif
155 #ifndef MAXPHYS
156 #define MAXPHYS (128 * 1024) /* max raw I/O transfer size */
157 #endif
158 #ifndef MAXDUMPPGS
159 #define MAXDUMPPGS (DFLTPHYS/PAGE_SIZE)
160 #endif
161
162 /*
163 * Constants related to network buffer management.
164 * MCLBYTES must be no larger than PAGE_SIZE.
165 */
166 #ifndef MSIZE
167 #define MSIZE 256 /* size of an mbuf */
168 #endif
169
170 #ifndef MCLSHIFT
171 #define MCLSHIFT 11 /* convert bytes to mbuf clusters */
172 #endif /* MCLSHIFT */
173
174 #define MCLBYTES (1 << MCLSHIFT) /* size of an mbuf cluster */
175
176 #if PAGE_SIZE < 2048
177 #define MJUMPAGESIZE MCLBYTES
178 #elif PAGE_SIZE <= 8192
179 #define MJUMPAGESIZE PAGE_SIZE
180 #else
181 #define MJUMPAGESIZE (8 * 1024)
182 #endif
183
184 #define MJUM9BYTES (9 * 1024) /* jumbo cluster 9k */
185 #define MJUM16BYTES (16 * 1024) /* jumbo cluster 16k */
186
187 /*
188 * Some macros for units conversion
189 */
190
191 /* clicks to bytes */
192 #ifndef ctob
193 #define ctob(x) ((x)<<PAGE_SHIFT)
194 #endif
195
196 /* bytes to clicks */
197 #ifndef btoc
198 #define btoc(x) (((vm_offset_t)(x)+PAGE_MASK)>>PAGE_SHIFT)
199 #endif
200
201 /*
202 * btodb() is messy and perhaps slow because `bytes' may be an off_t. We
203 * want to shift an unsigned type to avoid sign extension and we don't
204 * want to widen `bytes' unnecessarily. Assume that the result fits in
205 * a daddr_t.
206 */
207 #ifndef btodb
208 #define btodb(bytes) /* calculates (bytes / DEV_BSIZE) */ \
209 (sizeof (bytes) > sizeof(long) \
210 ? (daddr_t)((unsigned long long)(bytes) >> DEV_BSHIFT) \
211 : (daddr_t)((unsigned long)(bytes) >> DEV_BSHIFT))
212 #endif
213
214 #ifndef dbtob
215 #define dbtob(db) /* calculates (db * DEV_BSIZE) */ \
216 ((off_t)(db) << DEV_BSHIFT)
217 #endif
218
219 #define PRIMASK 0x0ff
220 #define PCATCH 0x100 /* OR'd with pri for tsleep to check signals */
221 #define PDROP 0x200 /* OR'd with pri to stop re-entry of interlock mutex */
222
223 #define NZERO 0 /* default "nice" */
224
225 #define NBBY 8 /* number of bits in a byte */
226 #define NBPW sizeof(int) /* number of bytes per word (integer) */
227
228 #define CMASK 022 /* default file mask: S_IWGRP|S_IWOTH */
229
230 #define NODEV (dev_t)(-1) /* non-existent device */
231
232 /*
233 * File system parameters and macros.
234 *
235 * MAXBSIZE - Filesystems are made out of blocks of at most MAXBSIZE bytes
236 * per block. MAXBSIZE may be made larger without effecting
237 * any existing filesystems as long as it does not exceed MAXPHYS,
238 * and may be made smaller at the risk of not being able to use
239 * filesystems which require a block size exceeding MAXBSIZE.
240 *
241 * MAXBCACHEBUF - Maximum size of a buffer in the buffer cache. This must
242 * be >= MAXBSIZE and can be set differently for different
243 * architectures by defining it in <machine/param.h>.
244 * Making this larger allows NFS to do larger reads/writes.
245 *
246 * BKVASIZE - Nominal buffer space per buffer, in bytes. BKVASIZE is the
247 * minimum KVM memory reservation the kernel is willing to make.
248 * Filesystems can of course request smaller chunks. Actual
249 * backing memory uses a chunk size of a page (PAGE_SIZE).
250 * The default value here can be overridden on a per-architecture
251 * basis by defining it in <machine/param.h>.
252 *
253 * If you make BKVASIZE too small you risk seriously fragmenting
254 * the buffer KVM map which may slow things down a bit. If you
255 * make it too big the kernel will not be able to optimally use
256 * the KVM memory reserved for the buffer cache and will wind
257 * up with too-few buffers.
258 *
259 * The default is 16384, roughly 2x the block size used by a
260 * normal UFS filesystem.
261 */
262 #define MAXBSIZE 65536 /* must be power of 2 */
263 #ifndef MAXBCACHEBUF
264 #define MAXBCACHEBUF MAXBSIZE /* must be a power of 2 >= MAXBSIZE */
265 #endif
266 #ifndef BKVASIZE
267 #define BKVASIZE 16384 /* must be power of 2 */
268 #endif
269 #define BKVAMASK (BKVASIZE-1)
270
271 /*
272 * MAXPATHLEN defines the longest permissible path length after expanding
273 * symbolic links. It is used to allocate a temporary buffer from the buffer
274 * pool in which to do the name expansion, hence should be a power of two,
275 * and must be less than or equal to MAXBSIZE. MAXSYMLINKS defines the
276 * maximum number of symbolic links that may be expanded in a path name.
277 * It should be set high enough to allow all legitimate uses, but halt
278 * infinite loops reasonably quickly.
279 */
280 #define MAXPATHLEN PATH_MAX
281 #define MAXSYMLINKS 32
282
283 /* Bit map related macros. */
284 #define setbit(a,i) (((unsigned char *)(a))[(i)/NBBY] |= 1<<((i)%NBBY))
285 #define clrbit(a,i) (((unsigned char *)(a))[(i)/NBBY] &= ~(1<<((i)%NBBY)))
286 #define isset(a,i) \
287 (((const unsigned char *)(a))[(i)/NBBY] & (1<<((i)%NBBY)))
288 #define isclr(a,i) \
289 ((((const unsigned char *)(a))[(i)/NBBY] & (1<<((i)%NBBY))) == 0)
290
291 /* Macros for counting and rounding. */
292 #ifndef howmany
293 #define howmany(x, y) (((x)+((y)-1))/(y))
294 #endif
295 #define nitems(x) (sizeof((x)) / sizeof((x)[0]))
296 #define rounddown(x, y) (((x)/(y))*(y))
297 #define rounddown2(x, y) ((x)&(~((y)-1))) /* if y is power of two */
298 #define roundup(x, y) ((((x)+((y)-1))/(y))*(y)) /* to any y */
299 #define roundup2(x, y) (((x)+((y)-1))&(~((y)-1))) /* if y is powers of two */
300 #define powerof2(x) ((((x)-1)&(x))==0)
301
302 /* Macros for min/max. */
303 #define MIN(a,b) (((a)<(b))?(a):(b))
304 #define MAX(a,b) (((a)>(b))?(a):(b))
305
306 #ifdef _KERNEL
307 /*
308 * Basic byte order function prototypes for non-inline functions.
309 */
310 #ifndef LOCORE
311 #ifndef _BYTEORDER_PROTOTYPED
312 #define _BYTEORDER_PROTOTYPED
313 __BEGIN_DECLS
314 __uint32_t htonl(__uint32_t);
315 __uint16_t htons(__uint16_t);
316 __uint32_t ntohl(__uint32_t);
317 __uint16_t ntohs(__uint16_t);
318 __END_DECLS
319 #endif
320 #endif
321
322 #ifndef lint
323 #ifndef _BYTEORDER_FUNC_DEFINED
324 #define _BYTEORDER_FUNC_DEFINED
325 #define htonl(x) __htonl(x)
326 #define htons(x) __htons(x)
327 #define ntohl(x) __ntohl(x)
328 #define ntohs(x) __ntohs(x)
329 #endif /* !_BYTEORDER_FUNC_DEFINED */
330 #endif /* lint */
331 #endif /* _KERNEL */
332
333 /*
334 * Scale factor for scaled integers used to count %cpu time and load avgs.
335 *
336 * The number of CPU `tick's that map to a unique `%age' can be expressed
337 * by the formula (1 / (2 ^ (FSHIFT - 11))). The maximum load average that
338 * can be calculated (assuming 32 bits) can be closely approximated using
339 * the formula (2 ^ (2 * (16 - FSHIFT))) for (FSHIFT < 15).
340 *
341 * For the scheduler to maintain a 1:1 mapping of CPU `tick' to `%age',
342 * FSHIFT must be at least 11; this gives us a maximum load avg of ~1024.
343 */
344 #define FSHIFT 11 /* bits to right of fixed binary point */
345 #define FSCALE (1<<FSHIFT)
346
347 #define dbtoc(db) /* calculates devblks to pages */ \
348 ((db + (ctodb(1) - 1)) >> (PAGE_SHIFT - DEV_BSHIFT))
349
350 #define ctodb(db) /* calculates pages to devblks */ \
351 ((db) << (PAGE_SHIFT - DEV_BSHIFT))
352
353 /*
354 * Old spelling of __containerof().
355 */
356 #define member2struct(s, m, x) \
357 ((struct s *)(void *)((char *)(x) - offsetof(struct s, m)))
358
359 /*
360 * Access a variable length array that has been declared as a fixed
361 * length array.
362 */
363 #define __PAST_END(array, offset) (((__typeof__(*(array)) *)(array))[offset])
364
365 #endif /* _SYS_PARAM_H_ */
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