xref: /freebsd-13-stable/sys/sys/param.h (revision 645ddc8048354b591d18330a512ad12da8d7190e)
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  */
38 
39 #ifndef _SYS_PARAM_H_
40 #define _SYS_PARAM_H_
41 
42 #include <sys/_null.h>
43 
44 #define	BSD	199506		/* System version (year & month). */
45 #define BSD4_3	1
46 #define BSD4_4	1
47 
48 /*
49  * __FreeBSD_version numbers are documented in the Porter's Handbook.
50  * If you bump the version for any reason, you should update the documentation
51  * there.
52  * Currently this lives here in the doc/ repository:
53  *
54  *	documentation/content/en/books/porters-handbook/versions/_index.adoc
55  *
56  * scheme is:  <major><two digit minor>Rxx
57  *		'R' is in the range 0 to 4 if this is a release branch or
58  *		X.0-CURRENT before releng/X.0 is created, otherwise 'R' is
59  *		in the range 5 to 9.
60  */
61 #undef __FreeBSD_version
62 #define __FreeBSD_version 1305500	/* Master, propagated to newvers */
63 
64 /*
65  * __FreeBSD_kernel__ indicates that this system uses the kernel of FreeBSD,
66  * which by definition is always true on FreeBSD. This macro is also defined
67  * on other systems that use the kernel of FreeBSD, such as GNU/kFreeBSD.
68  *
69  * It is tempting to use this macro in userland code when we want to enable
70  * kernel-specific routines, and in fact it's fine to do this in code that
71  * is part of FreeBSD itself.  However, be aware that as presence of this
72  * macro is still not widespread (e.g. older FreeBSD versions, 3rd party
73  * compilers, etc), it is STRONGLY DISCOURAGED to check for this macro in
74  * external applications without also checking for __FreeBSD__ as an
75  * alternative.
76  */
77 #undef __FreeBSD_kernel__
78 #define __FreeBSD_kernel__
79 
80 #if defined(_KERNEL) || defined(_WANT_P_OSREL)
81 #define	P_OSREL_SIGWAIT			700000
82 #define	P_OSREL_SIGSEGV			700004
83 #define	P_OSREL_MAP_ANON		800104
84 #define	P_OSREL_MAP_FSTRICT		1100036
85 #define	P_OSREL_SHUTDOWN_ENOTCONN	1100077
86 #define	P_OSREL_MAP_GUARD		1200035
87 #define	P_OSREL_WRFSBASE		1200041
88 #define	P_OSREL_CK_CYLGRP		1200046
89 #define	P_OSREL_VMTOTAL64		1200054
90 #define	P_OSREL_CK_SUPERBLOCK		1300000
91 #define	P_OSREL_CK_INODE		1300005
92 #define	P_OSREL_POWERPC_NEW_AUX_ARGS	1300070
93 #define	P_OSREL_TIDPID			1400079
94 #define	P_OSREL_TIDPID_13		1302501
95 
96 #define	P_OSREL_MAJOR(x)		((x) / 100000)
97 #endif
98 
99 #ifndef LOCORE
100 #include <sys/types.h>
101 #endif
102 
103 /*
104  * Machine-independent constants (some used in following include files).
105  * Redefined constants are from POSIX 1003.1 limits file.
106  *
107  * MAXCOMLEN should be >= sizeof(ac_comm) (see <acct.h>)
108  */
109 #include <sys/syslimits.h>
110 
111 #define	MAXCOMLEN	19		/* max command name remembered */
112 #define	MAXINTERP	PATH_MAX	/* max interpreter file name length */
113 #define	MAXLOGNAME	33		/* max login name length (incl. NUL) */
114 #define	MAXUPRC		CHILD_MAX	/* max simultaneous processes */
115 #define	NCARGS		ARG_MAX		/* max bytes for an exec function */
116 #define	NGROUPS		(NGROUPS_MAX+1)	/* max number groups */
117 #define	NOFILE		OPEN_MAX	/* max open files per process */
118 #define	NOGROUP		65535		/* marker for empty group set member */
119 #define MAXHOSTNAMELEN	256		/* max hostname size */
120 #define SPECNAMELEN	255		/* max length of devicename */
121 
122 /* More types and definitions used throughout the kernel. */
123 #ifdef _KERNEL
124 #include <sys/cdefs.h>
125 #include <sys/errno.h>
126 #ifndef LOCORE
127 #include <sys/time.h>
128 #include <sys/priority.h>
129 #endif
130 
131 #ifndef FALSE
132 #define	FALSE	0
133 #endif
134 #ifndef TRUE
135 #define	TRUE	1
136 #endif
137 #endif
138 
139 #ifndef _KERNEL
140 #ifndef LOCORE
141 /* Signals. */
142 #include <sys/signal.h>
143 #endif
144 #endif
145 
146 /* Machine type dependent parameters. */
147 #include <machine/param.h>
148 #ifndef _KERNEL
149 #include <sys/limits.h>
150 #endif
151 
152 #ifndef DEV_BSHIFT
153 #define	DEV_BSHIFT	9		/* log2(DEV_BSIZE) */
154 #endif
155 #define	DEV_BSIZE	(1<<DEV_BSHIFT)
156 
157 #ifndef BLKDEV_IOSIZE
158 #define BLKDEV_IOSIZE  PAGE_SIZE	/* default block device I/O size */
159 #endif
160 #ifndef DFLTPHYS
161 #define DFLTPHYS	(64 * 1024)	/* default max raw I/O transfer size */
162 #endif
163 #ifndef MAXPHYS				/* max raw I/O transfer size */
164 #ifdef __ILP32__
165 #define MAXPHYS		(128 * 1024)
166 #else
167 #define MAXPHYS		(1024 * 1024)
168 #endif
169 #endif
170 #ifndef MAXDUMPPGS
171 #define MAXDUMPPGS	(DFLTPHYS/PAGE_SIZE)
172 #endif
173 
174 /*
175  * Constants related to network buffer management.
176  * MCLBYTES must be no larger than PAGE_SIZE.
177  */
178 #ifndef	MSIZE
179 #define	MSIZE		256		/* size of an mbuf */
180 #endif
181 
182 #ifndef	MCLSHIFT
183 #define MCLSHIFT	11		/* convert bytes to mbuf clusters */
184 #endif	/* MCLSHIFT */
185 
186 #define MCLBYTES	(1 << MCLSHIFT)	/* size of an mbuf cluster */
187 
188 #if PAGE_SIZE < 2048
189 #define	MJUMPAGESIZE	MCLBYTES
190 #elif PAGE_SIZE <= 8192
191 #define	MJUMPAGESIZE	PAGE_SIZE
192 #else
193 #define	MJUMPAGESIZE	(8 * 1024)
194 #endif
195 
196 #define	MJUM9BYTES	(9 * 1024)	/* jumbo cluster 9k */
197 #define	MJUM16BYTES	(16 * 1024)	/* jumbo cluster 16k */
198 
199 /*
200  * Some macros for units conversion
201  */
202 
203 /* clicks to bytes */
204 #ifndef ctob
205 #define ctob(x)	((x)<<PAGE_SHIFT)
206 #endif
207 
208 /* bytes to clicks */
209 #ifndef btoc
210 #define btoc(x)	(((vm_offset_t)(x)+PAGE_MASK)>>PAGE_SHIFT)
211 #endif
212 
213 /*
214  * btodb() is messy and perhaps slow because `bytes' may be an off_t.  We
215  * want to shift an unsigned type to avoid sign extension and we don't
216  * want to widen `bytes' unnecessarily.  Assume that the result fits in
217  * a daddr_t.
218  */
219 #ifndef btodb
220 #define btodb(bytes)	 		/* calculates (bytes / DEV_BSIZE) */ \
221 	(sizeof (bytes) > sizeof(long) \
222 	 ? (daddr_t)((unsigned long long)(bytes) >> DEV_BSHIFT) \
223 	 : (daddr_t)((unsigned long)(bytes) >> DEV_BSHIFT))
224 #endif
225 
226 #ifndef dbtob
227 #define dbtob(db)			/* calculates (db * DEV_BSIZE) */ \
228 	((off_t)(db) << DEV_BSHIFT)
229 #endif
230 
231 #define	PRIMASK	0x0ff
232 #define	PCATCH	0x100		/* OR'd with pri for tsleep to check signals */
233 #define	PDROP	0x200	/* OR'd with pri to stop re-entry of interlock mutex */
234 
235 #define	NZERO	0		/* default "nice" */
236 
237 #define	NBBY	8		/* number of bits in a byte */
238 #define	NBPW	sizeof(int)	/* number of bytes per word (integer) */
239 
240 #define	CMASK	022		/* default file mask: S_IWGRP|S_IWOTH */
241 
242 #define	NODEV	(dev_t)(-1)	/* non-existent device */
243 
244 /*
245  * File system parameters and macros.
246  *
247  * MAXBSIZE -	Filesystems are made out of blocks of at most MAXBSIZE bytes
248  *		per block.  MAXBSIZE may be made larger without effecting
249  *		any existing filesystems as long as it does not exceed MAXPHYS,
250  *		and may be made smaller at the risk of not being able to use
251  *		filesystems which require a block size exceeding MAXBSIZE.
252  *
253  * MAXBCACHEBUF - Maximum size of a buffer in the buffer cache.  This must
254  *		be >= MAXBSIZE and can be set differently for different
255  *		architectures by defining it in <machine/param.h>.
256  *		Making this larger allows NFS to do larger reads/writes.
257  *
258  * BKVASIZE -	Nominal buffer space per buffer, in bytes.  BKVASIZE is the
259  *		minimum KVM memory reservation the kernel is willing to make.
260  *		Filesystems can of course request smaller chunks.  Actual
261  *		backing memory uses a chunk size of a page (PAGE_SIZE).
262  *		The default value here can be overridden on a per-architecture
263  *		basis by defining it in <machine/param.h>.
264  *
265  *		If you make BKVASIZE too small you risk seriously fragmenting
266  *		the buffer KVM map which may slow things down a bit.  If you
267  *		make it too big the kernel will not be able to optimally use
268  *		the KVM memory reserved for the buffer cache and will wind
269  *		up with too-few buffers.
270  *
271  *		The default is 16384, roughly 2x the block size used by a
272  *		normal UFS filesystem.
273  */
274 #define MAXBSIZE	65536	/* must be power of 2 */
275 #ifndef	MAXBCACHEBUF
276 #define	MAXBCACHEBUF	MAXBSIZE /* must be a power of 2 >= MAXBSIZE */
277 #endif
278 #ifndef	BKVASIZE
279 #define BKVASIZE	16384	/* must be power of 2 */
280 #endif
281 #define BKVAMASK	(BKVASIZE-1)
282 
283 /*
284  * MAXPATHLEN defines the longest permissible path length after expanding
285  * symbolic links. It is used to allocate a temporary buffer from the buffer
286  * pool in which to do the name expansion, hence should be a power of two,
287  * and must be less than or equal to MAXBSIZE.  MAXSYMLINKS defines the
288  * maximum number of symbolic links that may be expanded in a path name.
289  * It should be set high enough to allow all legitimate uses, but halt
290  * infinite loops reasonably quickly.
291  */
292 #define	MAXPATHLEN	PATH_MAX
293 #define MAXSYMLINKS	32
294 
295 /* Bit map related macros. */
296 #define	setbit(a,i)	(((unsigned char *)(a))[(i)/NBBY] |= 1<<((i)%NBBY))
297 #define	clrbit(a,i)	(((unsigned char *)(a))[(i)/NBBY] &= ~(1<<((i)%NBBY)))
298 #define	isset(a,i)							\
299 	(((const unsigned char *)(a))[(i)/NBBY] & (1<<((i)%NBBY)))
300 #define	isclr(a,i)							\
301 	((((const unsigned char *)(a))[(i)/NBBY] & (1<<((i)%NBBY))) == 0)
302 
303 /* Macros for counting and rounding. */
304 #ifndef howmany
305 #define	howmany(x, y)	(((x)+((y)-1))/(y))
306 #endif
307 #define	nitems(x)	(sizeof((x)) / sizeof((x)[0]))
308 #define	rounddown(x, y)	(((x)/(y))*(y))
309 #define	rounddown2(x, y) __align_down(x, y) /* if y is power of two */
310 #define	roundup(x, y)	((((x)+((y)-1))/(y))*(y))  /* to any y */
311 #define	roundup2(x, y)	__align_up(x, y) /* if y is powers of two */
312 #define powerof2(x)	((((x)-1)&(x))==0)
313 
314 /* Macros for min/max. */
315 #define	MIN(a,b) (((a)<(b))?(a):(b))
316 #define	MAX(a,b) (((a)>(b))?(a):(b))
317 
318 #ifdef _KERNEL
319 /*
320  * Basic byte order function prototypes for non-inline functions.
321  */
322 #ifndef LOCORE
323 #ifndef _BYTEORDER_PROTOTYPED
324 #define	_BYTEORDER_PROTOTYPED
325 __BEGIN_DECLS
326 __uint32_t	 htonl(__uint32_t);
327 __uint16_t	 htons(__uint16_t);
328 __uint32_t	 ntohl(__uint32_t);
329 __uint16_t	 ntohs(__uint16_t);
330 __END_DECLS
331 #endif
332 #endif
333 
334 #ifndef _BYTEORDER_FUNC_DEFINED
335 #define	_BYTEORDER_FUNC_DEFINED
336 #define	htonl(x)	__htonl(x)
337 #define	htons(x)	__htons(x)
338 #define	ntohl(x)	__ntohl(x)
339 #define	ntohs(x)	__ntohs(x)
340 #endif /* !_BYTEORDER_FUNC_DEFINED */
341 #endif /* _KERNEL */
342 
343 /*
344  * Scale factor for scaled integers used to count %cpu time and load avgs.
345  *
346  * The number of CPU `tick's that map to a unique `%age' can be expressed
347  * by the formula (1 / (2 ^ (FSHIFT - 11))).  Since the intermediate
348  * calculation is done with 64-bit precision, the maximum load average that can
349  * be calculated is approximately 2^32 / FSCALE.
350  *
351  * For the scheduler to maintain a 1:1 mapping of CPU `tick' to `%age',
352  * FSHIFT must be at least 11.  This gives a maximum load avg of 2 million.
353  */
354 #define	FSHIFT	11		/* bits to right of fixed binary point */
355 #define FSCALE	(1<<FSHIFT)
356 
357 #define dbtoc(db)			/* calculates devblks to pages */ \
358 	((db + (ctodb(1) - 1)) >> (PAGE_SHIFT - DEV_BSHIFT))
359 
360 #define ctodb(db)			/* calculates pages to devblks */ \
361 	((db) << (PAGE_SHIFT - DEV_BSHIFT))
362 
363 /*
364  * Old spelling of __containerof().
365  */
366 #define	member2struct(s, m, x)						\
367 	((struct s *)(void *)((char *)(x) - offsetof(struct s, m)))
368 
369 /*
370  * Access a variable length array that has been declared as a fixed
371  * length array.
372  */
373 #define __PAST_END(array, offset) (((__typeof__(*(array)) *)(array))[offset])
374 
375 #endif	/* _SYS_PARAM_H_ */
376