FreeBSD/Linux Kernel Cross Reference
sys/sys/param.h
1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1982, 1986, 1989, 1993
5 * The Regents of the University of California. All rights reserved.
6 * (c) UNIX System Laboratories, Inc.
7 * All or some portions of this file are derived from material licensed
8 * to the University of California by American Telephone and Telegraph
9 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
10 * the permission of UNIX System Laboratories, Inc.
11 *
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
14 * are met:
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 * notice, this list of conditions and the following disclaimer in the
19 * documentation and/or other materials provided with the distribution.
20 * 3. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 *
36 * @(#)param.h 8.3 (Berkeley) 4/4/95
37 * $FreeBSD$
38 */
39
40 #ifndef _SYS_PARAM_H_
41 #define _SYS_PARAM_H_
42
43 #include <sys/_null.h>
44
45 #define BSD 199506 /* System version (year & month). */
46 #define BSD4_3 1
47 #define BSD4_4 1
48
49 /*
50 * __FreeBSD_version numbers are documented in the Porter's Handbook.
51 * If you bump the version for any reason, you should update the documentation
52 * there.
53 * Currently this lives here in the doc/ repository:
54 *
55 * documentation/content/en/books/porters-handbook/versions/_index.adoc
56 *
57 * Encoding: <major><two digit minor>Rxx
58 * 'R' is in the range 0 to 4 if this is a release branch or
59 * X.0-CURRENT before releng/X.0 is created, otherwise 'R' is
60 * in the range 5 to 9.
61 * Short hand: MMmmXXX
62 *
63 * __FreeBSD_version is bumped every time there's a change in the base system
64 * that's noteworthy. A noteworthy change is any change which changes the
65 * kernel's KBI in -CURRENT, one that changes some detail about the system that
66 * external software (or the ports system) would want to know about, one that
67 * adds a system call, one that adds or deletes a shipped library, a security
68 * fix, or similar change not specifically noted here. Bumps should be limited
69 * to one per day / a couple per week except for security fixes.
70 *
71 * The approved way to obtain this from a shell script is:
72 * awk '/^\#define[[:space:]]*__FreeBSD_version/ {print $3}'
73 * Other methods to parse this file may work, but are not guaranteed against
74 * future changes. The above script works back to FreeBSD 3.x when this macro
75 * was introduced. This number is propagated to other places needing it that
76 * cannot include sys/param.h and should only be updated here.
77 */
78 #undef __FreeBSD_version
79 #define __FreeBSD_version 1400078
80
81 /*
82 * __FreeBSD_kernel__ indicates that this system uses the kernel of FreeBSD,
83 * which by definition is always true on FreeBSD. This macro is also defined
84 * on other systems that use the kernel of FreeBSD, such as GNU/kFreeBSD.
85 *
86 * It is tempting to use this macro in userland code when we want to enable
87 * kernel-specific routines, and in fact it's fine to do this in code that
88 * is part of FreeBSD itself. However, be aware that as presence of this
89 * macro is still not widespread (e.g. older FreeBSD versions, 3rd party
90 * compilers, etc), it is STRONGLY DISCOURAGED to check for this macro in
91 * external applications without also checking for __FreeBSD__ as an
92 * alternative.
93 */
94 #undef __FreeBSD_kernel__
95 #define __FreeBSD_kernel__
96
97 #if defined(_KERNEL) || defined(IN_RTLD)
98 #define P_OSREL_SIGWAIT 700000
99 #define P_OSREL_SIGSEGV 700004
100 #define P_OSREL_MAP_ANON 800104
101 #define P_OSREL_MAP_FSTRICT 1100036
102 #define P_OSREL_SHUTDOWN_ENOTCONN 1100077
103 #define P_OSREL_MAP_GUARD 1200035
104 #define P_OSREL_WRFSBASE 1200041
105 #define P_OSREL_CK_CYLGRP 1200046
106 #define P_OSREL_VMTOTAL64 1200054
107 #define P_OSREL_CK_SUPERBLOCK 1300000
108 #define P_OSREL_CK_INODE 1300005
109 #define P_OSREL_POWERPC_NEW_AUX_ARGS 1300070
110
111 #define P_OSREL_MAJOR(x) ((x) / 100000)
112 #endif
113
114 #ifndef LOCORE
115 #include <sys/types.h>
116 #endif
117
118 /*
119 * Machine-independent constants (some used in following include files).
120 * Redefined constants are from POSIX 1003.1 limits file.
121 *
122 * MAXCOMLEN should be >= sizeof(ac_comm) (see <acct.h>)
123 */
124 #include <sys/syslimits.h>
125
126 #define MAXCOMLEN 19 /* max command name remembered */
127 #define MAXINTERP PATH_MAX /* max interpreter file name length */
128 #define MAXLOGNAME 33 /* max login name length (incl. NUL) */
129 #define MAXUPRC CHILD_MAX /* max simultaneous processes */
130 #define NCARGS ARG_MAX /* max bytes for an exec function */
131 #define NGROUPS (NGROUPS_MAX+1) /* max number groups */
132 #define NOFILE OPEN_MAX /* max open files per process */
133 #define NOGROUP 65535 /* marker for empty group set member */
134 #define MAXHOSTNAMELEN 256 /* max hostname size */
135 #define SPECNAMELEN 255 /* max length of devicename */
136
137 /* More types and definitions used throughout the kernel. */
138 #ifdef _KERNEL
139 #include <sys/cdefs.h>
140 #include <sys/errno.h>
141 #ifndef LOCORE
142 #include <sys/time.h>
143 #include <sys/priority.h>
144 #endif
145
146 #ifndef FALSE
147 #define FALSE 0
148 #endif
149 #ifndef TRUE
150 #define TRUE 1
151 #endif
152 #endif
153
154 #ifndef _KERNEL
155 #ifndef LOCORE
156 /* Signals. */
157 #include <sys/signal.h>
158 #endif
159 #endif
160
161 /* Machine type dependent parameters. */
162 #include <machine/param.h>
163 #ifndef _KERNEL
164 #include <sys/limits.h>
165 #endif
166
167 #ifndef DEV_BSHIFT
168 #define DEV_BSHIFT 9 /* log2(DEV_BSIZE) */
169 #endif
170 #define DEV_BSIZE (1<<DEV_BSHIFT)
171
172 #ifndef BLKDEV_IOSIZE
173 #define BLKDEV_IOSIZE PAGE_SIZE /* default block device I/O size */
174 #endif
175 #ifndef DFLTPHYS
176 #define DFLTPHYS (64 * 1024) /* default max raw I/O transfer size */
177 #endif
178 #ifndef MAXPHYS /* max raw I/O transfer size */
179 #ifdef __ILP32__
180 #define MAXPHYS (128 * 1024)
181 #else
182 #define MAXPHYS (1024 * 1024)
183 #endif
184 #endif
185 #ifndef MAXDUMPPGS
186 #define MAXDUMPPGS (DFLTPHYS/PAGE_SIZE)
187 #endif
188
189 /*
190 * Constants related to network buffer management.
191 * MCLBYTES must be no larger than PAGE_SIZE.
192 */
193 #ifndef MSIZE
194 #define MSIZE 256 /* size of an mbuf */
195 #endif
196
197 #ifndef MCLSHIFT
198 #define MCLSHIFT 11 /* convert bytes to mbuf clusters */
199 #endif /* MCLSHIFT */
200
201 #define MCLBYTES (1 << MCLSHIFT) /* size of an mbuf cluster */
202
203 #if PAGE_SIZE <= 8192
204 #define MJUMPAGESIZE PAGE_SIZE
205 #else
206 #define MJUMPAGESIZE (8 * 1024)
207 #endif
208
209 #define MJUM9BYTES (9 * 1024) /* jumbo cluster 9k */
210 #define MJUM16BYTES (16 * 1024) /* jumbo cluster 16k */
211
212 /*
213 * Some macros for units conversion
214 */
215
216 /* clicks to bytes */
217 #ifndef ctob
218 #define ctob(x) ((x)<<PAGE_SHIFT)
219 #endif
220
221 /* bytes to clicks */
222 #ifndef btoc
223 #define btoc(x) (((vm_offset_t)(x)+PAGE_MASK)>>PAGE_SHIFT)
224 #endif
225
226 /*
227 * btodb() is messy and perhaps slow because `bytes' may be an off_t. We
228 * want to shift an unsigned type to avoid sign extension and we don't
229 * want to widen `bytes' unnecessarily. Assume that the result fits in
230 * a daddr_t.
231 */
232 #ifndef btodb
233 #define btodb(bytes) /* calculates (bytes / DEV_BSIZE) */ \
234 (sizeof (bytes) > sizeof(long) \
235 ? (daddr_t)((unsigned long long)(bytes) >> DEV_BSHIFT) \
236 : (daddr_t)((unsigned long)(bytes) >> DEV_BSHIFT))
237 #endif
238
239 #ifndef dbtob
240 #define dbtob(db) /* calculates (db * DEV_BSIZE) */ \
241 ((off_t)(db) << DEV_BSHIFT)
242 #endif
243
244 #define PRIMASK 0x0ff
245 #define PCATCH 0x100 /* OR'd with pri for tsleep to check signals */
246 #define PDROP 0x200 /* OR'd with pri to stop re-entry of interlock mutex */
247 #define PNOLOCK 0x400 /* OR'd with pri to allow sleeping w/o a lock */
248 #define PRILASTFLAG 0x400 /* Last flag defined above */
249
250 #define NZERO 0 /* default "nice" */
251
252 #define NBBY 8 /* number of bits in a byte */
253 #define NBPW sizeof(int) /* number of bytes per word (integer) */
254
255 #define CMASK 022 /* default file mask: S_IWGRP|S_IWOTH */
256
257 #define NODEV (dev_t)(-1) /* non-existent device */
258
259 /*
260 * File system parameters and macros.
261 *
262 * MAXBSIZE - Filesystems are made out of blocks of at most MAXBSIZE bytes
263 * per block. MAXBSIZE may be made larger without effecting
264 * any existing filesystems as long as it does not exceed MAXPHYS,
265 * and may be made smaller at the risk of not being able to use
266 * filesystems which require a block size exceeding MAXBSIZE.
267 *
268 * MAXBCACHEBUF - Maximum size of a buffer in the buffer cache. This must
269 * be >= MAXBSIZE and can be set differently for different
270 * architectures by defining it in <machine/param.h>.
271 * Making this larger allows NFS to do larger reads/writes.
272 *
273 * BKVASIZE - Nominal buffer space per buffer, in bytes. BKVASIZE is the
274 * minimum KVM memory reservation the kernel is willing to make.
275 * Filesystems can of course request smaller chunks. Actual
276 * backing memory uses a chunk size of a page (PAGE_SIZE).
277 * The default value here can be overridden on a per-architecture
278 * basis by defining it in <machine/param.h>.
279 *
280 * If you make BKVASIZE too small you risk seriously fragmenting
281 * the buffer KVM map which may slow things down a bit. If you
282 * make it too big the kernel will not be able to optimally use
283 * the KVM memory reserved for the buffer cache and will wind
284 * up with too-few buffers.
285 *
286 * The default is 16384, roughly 2x the block size used by a
287 * normal UFS filesystem.
288 */
289 #define MAXBSIZE 65536 /* must be power of 2 */
290 #ifndef MAXBCACHEBUF
291 #define MAXBCACHEBUF MAXBSIZE /* must be a power of 2 >= MAXBSIZE */
292 #endif
293 #ifndef BKVASIZE
294 #define BKVASIZE 16384 /* must be power of 2 */
295 #endif
296 #define BKVAMASK (BKVASIZE-1)
297
298 /*
299 * MAXPATHLEN defines the longest permissible path length after expanding
300 * symbolic links. It is used to allocate a temporary buffer from the buffer
301 * pool in which to do the name expansion, hence should be a power of two,
302 * and must be less than or equal to MAXBSIZE. MAXSYMLINKS defines the
303 * maximum number of symbolic links that may be expanded in a path name.
304 * It should be set high enough to allow all legitimate uses, but halt
305 * infinite loops reasonably quickly.
306 */
307 #define MAXPATHLEN PATH_MAX
308 #define MAXSYMLINKS 32
309
310 /* Bit map related macros. */
311 #define setbit(a,i) (((unsigned char *)(a))[(i)/NBBY] |= 1<<((i)%NBBY))
312 #define clrbit(a,i) (((unsigned char *)(a))[(i)/NBBY] &= ~(1<<((i)%NBBY)))
313 #define isset(a,i) \
314 (((const unsigned char *)(a))[(i)/NBBY] & (1<<((i)%NBBY)))
315 #define isclr(a,i) \
316 ((((const unsigned char *)(a))[(i)/NBBY] & (1<<((i)%NBBY))) == 0)
317
318 /* Macros for counting and rounding. */
319 #ifndef howmany
320 #define howmany(x, y) (((x)+((y)-1))/(y))
321 #endif
322 #define nitems(x) (sizeof((x)) / sizeof((x)[0]))
323 #define rounddown(x, y) (((x)/(y))*(y))
324 #define rounddown2(x, y) __align_down(x, y) /* if y is power of two */
325 #define roundup(x, y) ((((x)+((y)-1))/(y))*(y)) /* to any y */
326 #define roundup2(x, y) __align_up(x, y) /* if y is powers of two */
327 #define powerof2(x) ((((x)-1)&(x))==0)
328
329 /* Macros for min/max. */
330 #define MIN(a,b) (((a)<(b))?(a):(b))
331 #define MAX(a,b) (((a)>(b))?(a):(b))
332
333 #ifdef _KERNEL
334 /*
335 * Basic byte order function prototypes for non-inline functions.
336 */
337 #ifndef LOCORE
338 #ifndef _BYTEORDER_PROTOTYPED
339 #define _BYTEORDER_PROTOTYPED
340 __BEGIN_DECLS
341 __uint32_t htonl(__uint32_t);
342 __uint16_t htons(__uint16_t);
343 __uint32_t ntohl(__uint32_t);
344 __uint16_t ntohs(__uint16_t);
345 __END_DECLS
346 #endif
347 #endif
348
349 #ifndef _BYTEORDER_FUNC_DEFINED
350 #define _BYTEORDER_FUNC_DEFINED
351 #define htonl(x) __htonl(x)
352 #define htons(x) __htons(x)
353 #define ntohl(x) __ntohl(x)
354 #define ntohs(x) __ntohs(x)
355 #endif /* !_BYTEORDER_FUNC_DEFINED */
356 #endif /* _KERNEL */
357
358 /*
359 * Scale factor for scaled integers used to count %cpu time and load avgs.
360 *
361 * The number of CPU `tick's that map to a unique `%age' can be expressed
362 * by the formula (1 / (2 ^ (FSHIFT - 11))). Since the intermediate
363 * calculation is done with 64-bit precision, the maximum load average that can
364 * be calculated is approximately 2^32 / FSCALE.
365 *
366 * For the scheduler to maintain a 1:1 mapping of CPU `tick' to `%age',
367 * FSHIFT must be at least 11. This gives a maximum load avg of 2 million.
368 */
369 #define FSHIFT 11 /* bits to right of fixed binary point */
370 #define FSCALE (1<<FSHIFT)
371
372 #define dbtoc(db) /* calculates devblks to pages */ \
373 ((db + (ctodb(1) - 1)) >> (PAGE_SHIFT - DEV_BSHIFT))
374
375 #define ctodb(db) /* calculates pages to devblks */ \
376 ((db) << (PAGE_SHIFT - DEV_BSHIFT))
377
378 /*
379 * Old spelling of __containerof().
380 */
381 #define member2struct(s, m, x) \
382 ((struct s *)(void *)((char *)(x) - offsetof(struct s, m)))
383
384 /*
385 * Access a variable length array that has been declared as a fixed
386 * length array.
387 */
388 #define __PAST_END(array, offset) (((__typeof__(*(array)) *)(array))[offset])
389
390 #endif /* _SYS_PARAM_H_ */
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