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/11.1/sys/sys/param.h 320763 2017-07-07 06:29:18Z kib $
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 1101001 /* 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_MAP_GUARD_11_1 1101001
88
89 #define P_OSREL_MAJOR(x) ((x) / 100000)
90 #endif
91
92 #ifndef LOCORE
93 #include <sys/types.h>
94 #endif
95
96 /*
97 * Machine-independent constants (some used in following include files).
98 * Redefined constants are from POSIX 1003.1 limits file.
99 *
100 * MAXCOMLEN should be >= sizeof(ac_comm) (see <acct.h>)
101 */
102 #include <sys/syslimits.h>
103
104 #define MAXCOMLEN 19 /* max command name remembered */
105 #define MAXINTERP PATH_MAX /* max interpreter file name length */
106 #define MAXLOGNAME 33 /* max login name length (incl. NUL) */
107 #define MAXUPRC CHILD_MAX /* max simultaneous processes */
108 #define NCARGS ARG_MAX /* max bytes for an exec function */
109 #define NGROUPS (NGROUPS_MAX+1) /* max number groups */
110 #define NOFILE OPEN_MAX /* max open files per process */
111 #define NOGROUP 65535 /* marker for empty group set member */
112 #define MAXHOSTNAMELEN 256 /* max hostname size */
113 #define SPECNAMELEN 63 /* max length of devicename */
114
115 /* More types and definitions used throughout the kernel. */
116 #ifdef _KERNEL
117 #include <sys/cdefs.h>
118 #include <sys/errno.h>
119 #ifndef LOCORE
120 #include <sys/time.h>
121 #include <sys/priority.h>
122 #endif
123
124 #ifndef FALSE
125 #define FALSE 0
126 #endif
127 #ifndef TRUE
128 #define TRUE 1
129 #endif
130 #endif
131
132 #ifndef _KERNEL
133 /* Signals. */
134 #include <sys/signal.h>
135 #endif
136
137 /* Machine type dependent parameters. */
138 #include <machine/param.h>
139 #ifndef _KERNEL
140 #include <sys/limits.h>
141 #endif
142
143 #ifndef DEV_BSHIFT
144 #define DEV_BSHIFT 9 /* log2(DEV_BSIZE) */
145 #endif
146 #define DEV_BSIZE (1<<DEV_BSHIFT)
147
148 #ifndef BLKDEV_IOSIZE
149 #define BLKDEV_IOSIZE PAGE_SIZE /* default block device I/O size */
150 #endif
151 #ifndef DFLTPHYS
152 #define DFLTPHYS (64 * 1024) /* default max raw I/O transfer size */
153 #endif
154 #ifndef MAXPHYS
155 #define MAXPHYS (128 * 1024) /* max raw I/O transfer size */
156 #endif
157 #ifndef MAXDUMPPGS
158 #define MAXDUMPPGS (DFLTPHYS/PAGE_SIZE)
159 #endif
160
161 /*
162 * Constants related to network buffer management.
163 * MCLBYTES must be no larger than PAGE_SIZE.
164 */
165 #ifndef MSIZE
166 #define MSIZE 256 /* size of an mbuf */
167 #endif
168
169 #ifndef MCLSHIFT
170 #define MCLSHIFT 11 /* convert bytes to mbuf clusters */
171 #endif /* MCLSHIFT */
172
173 #define MCLBYTES (1 << MCLSHIFT) /* size of an mbuf cluster */
174
175 #if PAGE_SIZE < 2048
176 #define MJUMPAGESIZE MCLBYTES
177 #elif PAGE_SIZE <= 8192
178 #define MJUMPAGESIZE PAGE_SIZE
179 #else
180 #define MJUMPAGESIZE (8 * 1024)
181 #endif
182
183 #define MJUM9BYTES (9 * 1024) /* jumbo cluster 9k */
184 #define MJUM16BYTES (16 * 1024) /* jumbo cluster 16k */
185
186 /*
187 * Some macros for units conversion
188 */
189
190 /* clicks to bytes */
191 #ifndef ctob
192 #define ctob(x) ((x)<<PAGE_SHIFT)
193 #endif
194
195 /* bytes to clicks */
196 #ifndef btoc
197 #define btoc(x) (((vm_offset_t)(x)+PAGE_MASK)>>PAGE_SHIFT)
198 #endif
199
200 /*
201 * btodb() is messy and perhaps slow because `bytes' may be an off_t. We
202 * want to shift an unsigned type to avoid sign extension and we don't
203 * want to widen `bytes' unnecessarily. Assume that the result fits in
204 * a daddr_t.
205 */
206 #ifndef btodb
207 #define btodb(bytes) /* calculates (bytes / DEV_BSIZE) */ \
208 (sizeof (bytes) > sizeof(long) \
209 ? (daddr_t)((unsigned long long)(bytes) >> DEV_BSHIFT) \
210 : (daddr_t)((unsigned long)(bytes) >> DEV_BSHIFT))
211 #endif
212
213 #ifndef dbtob
214 #define dbtob(db) /* calculates (db * DEV_BSIZE) */ \
215 ((off_t)(db) << DEV_BSHIFT)
216 #endif
217
218 #define PRIMASK 0x0ff
219 #define PCATCH 0x100 /* OR'd with pri for tsleep to check signals */
220 #define PDROP 0x200 /* OR'd with pri to stop re-entry of interlock mutex */
221
222 #define NZERO 0 /* default "nice" */
223
224 #define NBBY 8 /* number of bits in a byte */
225 #define NBPW sizeof(int) /* number of bytes per word (integer) */
226
227 #define CMASK 022 /* default file mask: S_IWGRP|S_IWOTH */
228
229 #define NODEV (dev_t)(-1) /* non-existent device */
230
231 /*
232 * File system parameters and macros.
233 *
234 * MAXBSIZE - Filesystems are made out of blocks of at most MAXBSIZE bytes
235 * per block. MAXBSIZE may be made larger without effecting
236 * any existing filesystems as long as it does not exceed MAXPHYS,
237 * and may be made smaller at the risk of not being able to use
238 * filesystems which require a block size exceeding MAXBSIZE.
239 *
240 * MAXBCACHEBUF - Maximum size of a buffer in the buffer cache. This must
241 * be >= MAXBSIZE and can be set differently for different
242 * architectures by defining it in <machine/param.h>.
243 * Making this larger allows NFS to do larger reads/writes.
244 *
245 * BKVASIZE - Nominal buffer space per buffer, in bytes. BKVASIZE is the
246 * minimum KVM memory reservation the kernel is willing to make.
247 * Filesystems can of course request smaller chunks. Actual
248 * backing memory uses a chunk size of a page (PAGE_SIZE).
249 * The default value here can be overridden on a per-architecture
250 * basis by defining it in <machine/param.h>. This should
251 * probably be done to increase its value, when MAXBCACHEBUF is
252 * defined as a larger value in <machine/param.h>.
253 *
254 * If you make BKVASIZE too small you risk seriously fragmenting
255 * the buffer KVM map which may slow things down a bit. If you
256 * make it too big the kernel will not be able to optimally use
257 * the KVM memory reserved for the buffer cache and will wind
258 * up with too-few buffers.
259 *
260 * The default is 16384, roughly 2x the block size used by a
261 * normal UFS filesystem.
262 */
263 #define MAXBSIZE 65536 /* must be power of 2 */
264 #ifndef MAXBCACHEBUF
265 #define MAXBCACHEBUF MAXBSIZE /* must be a power of 2 >= MAXBSIZE */
266 #endif
267 #ifndef BKVASIZE
268 #define BKVASIZE 16384 /* must be power of 2 */
269 #endif
270 #define BKVAMASK (BKVASIZE-1)
271
272 /*
273 * MAXPATHLEN defines the longest permissible path length after expanding
274 * symbolic links. It is used to allocate a temporary buffer from the buffer
275 * pool in which to do the name expansion, hence should be a power of two,
276 * and must be less than or equal to MAXBSIZE. MAXSYMLINKS defines the
277 * maximum number of symbolic links that may be expanded in a path name.
278 * It should be set high enough to allow all legitimate uses, but halt
279 * infinite loops reasonably quickly.
280 */
281 #define MAXPATHLEN PATH_MAX
282 #define MAXSYMLINKS 32
283
284 /* Bit map related macros. */
285 #define setbit(a,i) (((unsigned char *)(a))[(i)/NBBY] |= 1<<((i)%NBBY))
286 #define clrbit(a,i) (((unsigned char *)(a))[(i)/NBBY] &= ~(1<<((i)%NBBY)))
287 #define isset(a,i) \
288 (((const unsigned char *)(a))[(i)/NBBY] & (1<<((i)%NBBY)))
289 #define isclr(a,i) \
290 ((((const unsigned char *)(a))[(i)/NBBY] & (1<<((i)%NBBY))) == 0)
291
292 /* Macros for counting and rounding. */
293 #ifndef howmany
294 #define howmany(x, y) (((x)+((y)-1))/(y))
295 #endif
296 #define nitems(x) (sizeof((x)) / sizeof((x)[0]))
297 #define rounddown(x, y) (((x)/(y))*(y))
298 #define rounddown2(x, y) ((x)&(~((y)-1))) /* if y is power of two */
299 #define roundup(x, y) ((((x)+((y)-1))/(y))*(y)) /* to any y */
300 #define roundup2(x, y) (((x)+((y)-1))&(~((y)-1))) /* if y is powers of two */
301 #define powerof2(x) ((((x)-1)&(x))==0)
302
303 /* Macros for min/max. */
304 #define MIN(a,b) (((a)<(b))?(a):(b))
305 #define MAX(a,b) (((a)>(b))?(a):(b))
306
307 #ifdef _KERNEL
308 /*
309 * Basic byte order function prototypes for non-inline functions.
310 */
311 #ifndef LOCORE
312 #ifndef _BYTEORDER_PROTOTYPED
313 #define _BYTEORDER_PROTOTYPED
314 __BEGIN_DECLS
315 __uint32_t htonl(__uint32_t);
316 __uint16_t htons(__uint16_t);
317 __uint32_t ntohl(__uint32_t);
318 __uint16_t ntohs(__uint16_t);
319 __END_DECLS
320 #endif
321 #endif
322
323 #ifndef lint
324 #ifndef _BYTEORDER_FUNC_DEFINED
325 #define _BYTEORDER_FUNC_DEFINED
326 #define htonl(x) __htonl(x)
327 #define htons(x) __htons(x)
328 #define ntohl(x) __ntohl(x)
329 #define ntohs(x) __ntohs(x)
330 #endif /* !_BYTEORDER_FUNC_DEFINED */
331 #endif /* lint */
332 #endif /* _KERNEL */
333
334 /*
335 * Scale factor for scaled integers used to count %cpu time and load avgs.
336 *
337 * The number of CPU `tick's that map to a unique `%age' can be expressed
338 * by the formula (1 / (2 ^ (FSHIFT - 11))). The maximum load average that
339 * can be calculated (assuming 32 bits) can be closely approximated using
340 * the formula (2 ^ (2 * (16 - FSHIFT))) for (FSHIFT < 15).
341 *
342 * For the scheduler to maintain a 1:1 mapping of CPU `tick' to `%age',
343 * FSHIFT must be at least 11; this gives us a maximum load avg of ~1024.
344 */
345 #define FSHIFT 11 /* bits to right of fixed binary point */
346 #define FSCALE (1<<FSHIFT)
347
348 #define dbtoc(db) /* calculates devblks to pages */ \
349 ((db + (ctodb(1) - 1)) >> (PAGE_SHIFT - DEV_BSHIFT))
350
351 #define ctodb(db) /* calculates pages to devblks */ \
352 ((db) << (PAGE_SHIFT - DEV_BSHIFT))
353
354 /*
355 * Old spelling of __containerof().
356 */
357 #define member2struct(s, m, x) \
358 ((struct s *)(void *)((char *)(x) - offsetof(struct s, m)))
359
360 /*
361 * Access a variable length array that has been declared as a fixed
362 * length array.
363 */
364 #define __PAST_END(array, offset) (((__typeof__(*(array)) *)(array))[offset])
365
366 #endif /* _SYS_PARAM_H_ */
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