xref: /freebsd/sys/sys/param.h (revision cab31f5633c1ffdd8b24749a3c9dd22c59568503)
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 
37 #ifndef _SYS_PARAM_H_
38 #define _SYS_PARAM_H_
39 
40 #include <sys/_null.h>
41 
42 #define	BSD	199506		/* System version (year & month). */
43 #define BSD4_3	1
44 #define BSD4_4	1
45 
46 /*
47  * __FreeBSD_version numbers are documented in the Porter's Handbook.
48  * If you bump the version for any reason, you should update the documentation
49  * there.
50  * Currently this lives here in the doc/ repository:
51  *
52  *	documentation/content/en/books/porters-handbook/versions/_index.adoc
53  *
54  * Encoding:	<major><two digit minor>Rxx
55  *		'R' is in the range 0 to 4 if this is a release branch or
56  *		X.0-CURRENT before releng/X.0 is created, otherwise 'R' is
57  *		in the range 5 to 9.
58  * Short hand: MMmmXXX
59  *
60  * __FreeBSD_version is bumped every time there's a change in the base system
61  * that's noteworthy. A noteworthy change is any change which changes the
62  * kernel's KBI in -CURRENT, one that changes some detail about the system that
63  * external software (or the ports system) would want to know about, one that
64  * adds a system call, one that adds or deletes a shipped library, a security
65  * fix, or similar change not specifically noted here. Bumps should be limited
66  * to one per day / a couple per week except for security fixes.
67  *
68  * The approved way to obtain this from a shell script is:
69  *	awk '/^\#define[[:space:]]*__FreeBSD_version/ {print $3}'
70  * Other methods to parse this file may work, but are not guaranteed against
71  * future changes. The above script works back to FreeBSD 3.x when this macro
72  * was introduced. This number is propagated to other places needing it that
73  * cannot include sys/param.h and should only be updated here.
74  */
75 #undef __FreeBSD_version
76 #define __FreeBSD_version 1500028
77 
78 /*
79  * __FreeBSD_kernel__ indicates that this system uses the kernel of FreeBSD,
80  * which by definition is always true on FreeBSD. This macro is also defined
81  * on other systems that use the kernel of FreeBSD, such as GNU/kFreeBSD.
82  *
83  * It is tempting to use this macro in userland code when we want to enable
84  * kernel-specific routines, and in fact it's fine to do this in code that
85  * is part of FreeBSD itself.  However, be aware that as presence of this
86  * macro is still not widespread (e.g. older FreeBSD versions, 3rd party
87  * compilers, etc), it is STRONGLY DISCOURAGED to check for this macro in
88  * external applications without also checking for __FreeBSD__ as an
89  * alternative.
90  */
91 #undef __FreeBSD_kernel__
92 #define __FreeBSD_kernel__
93 
94 #if defined(_KERNEL) || defined(_WANT_P_OSREL)
95 #define	P_OSREL_SIGWAIT			700000
96 #define	P_OSREL_SIGSEGV			700004
97 #define	P_OSREL_MAP_ANON		800104
98 #define	P_OSREL_MAP_FSTRICT		1100036
99 #define	P_OSREL_SHUTDOWN_ENOTCONN	1100077
100 #define	P_OSREL_MAP_GUARD		1200035
101 #define	P_OSREL_WRFSBASE		1200041
102 #define	P_OSREL_CK_CYLGRP		1200046
103 #define	P_OSREL_VMTOTAL64		1200054
104 #define	P_OSREL_CK_SUPERBLOCK		1300000
105 #define	P_OSREL_CK_INODE		1300005
106 #define	P_OSREL_POWERPC_NEW_AUX_ARGS	1300070
107 #define	P_OSREL_TIDPID			1400079
108 #define	P_OSREL_ARM64_SPSR		1400084
109 
110 #define	P_OSREL_MAJOR(x)		((x) / 100000)
111 #endif
112 
113 #ifndef LOCORE
114 #include <sys/types.h>
115 #endif
116 
117 /*
118  * Machine-independent constants (some used in following include files).
119  * Redefined constants are from POSIX 1003.1 limits file.
120  *
121  * MAXCOMLEN should be >= sizeof(ac_comm) (see <acct.h>)
122  */
123 #include <sys/syslimits.h>
124 
125 #define	MAXCOMLEN	19		/* max command name remembered */
126 #define	MAXINTERP	PATH_MAX	/* max interpreter file name length */
127 #define	MAXLOGNAME	33		/* max login name length (incl. NUL) */
128 #define	MAXUPRC		CHILD_MAX	/* max simultaneous processes */
129 #define	NCARGS		ARG_MAX		/* max bytes for an exec function */
130 #define	NGROUPS		(NGROUPS_MAX+1)	/* max number groups */
131 #define	NOFILE		OPEN_MAX	/* max open files per process */
132 #define	NOGROUP		65535		/* marker for empty group set member */
133 #define MAXHOSTNAMELEN	256		/* max hostname size */
134 #define SPECNAMELEN	255		/* max length of devicename */
135 
136 /* More types and definitions used throughout the kernel. */
137 #ifdef _KERNEL
138 #include <sys/cdefs.h>
139 #include <sys/errno.h>
140 #ifndef LOCORE
141 #include <sys/time.h>
142 #include <sys/priority.h>
143 #endif
144 
145 #ifndef FALSE
146 #define	FALSE	0
147 #endif
148 #ifndef TRUE
149 #define	TRUE	1
150 #endif
151 #endif
152 
153 #if !defined(_KERNEL) && !defined(_STANDALONE) && !defined(LOCORE)
154 /* Signals. */
155 #include <sys/signal.h>
156 #endif
157 
158 /* Machine type dependent parameters. */
159 #include <machine/param.h>
160 #ifndef _KERNEL
161 #include <sys/limits.h>
162 #include <sys/_maxphys.h>
163 #endif
164 
165 #ifndef DEV_BSHIFT
166 #define	DEV_BSHIFT	9		/* log2(DEV_BSIZE) */
167 #endif
168 #define	DEV_BSIZE	(1<<DEV_BSHIFT)
169 
170 #ifndef BLKDEV_IOSIZE
171 #define BLKDEV_IOSIZE  PAGE_SIZE	/* default block device I/O size */
172 #endif
173 #ifndef DFLTPHYS
174 #define DFLTPHYS	(64 * 1024)	/* default max raw I/O transfer size */
175 #endif
176 #ifndef MAXDUMPPGS
177 #define MAXDUMPPGS	(DFLTPHYS/PAGE_SIZE)
178 #endif
179 
180 /*
181  * Constants related to network buffer management.
182  * MCLBYTES must be no larger than PAGE_SIZE.
183  */
184 #ifndef	MSIZE
185 #define	MSIZE		256		/* size of an mbuf */
186 #endif
187 
188 #ifndef	MCLSHIFT
189 #define MCLSHIFT	11		/* convert bytes to mbuf clusters */
190 #endif	/* MCLSHIFT */
191 
192 #define MCLBYTES	(1 << MCLSHIFT)	/* size of an mbuf cluster */
193 
194 #if PAGE_SIZE <= 8192
195 #define	MJUMPAGESIZE	PAGE_SIZE
196 #else
197 #define	MJUMPAGESIZE	(8 * 1024)
198 #endif
199 
200 #define	MJUM9BYTES	(9 * 1024)	/* jumbo cluster 9k */
201 #define	MJUM16BYTES	(16 * 1024)	/* jumbo cluster 16k */
202 
203 /*
204  * Some macros for units conversion
205  */
206 
207 /* clicks to bytes */
208 #ifndef ctob
209 #define ctob(x)	((x)<<PAGE_SHIFT)
210 #endif
211 
212 /* bytes to clicks */
213 #ifndef btoc
214 #define btoc(x)	(((vm_offset_t)(x)+PAGE_MASK)>>PAGE_SHIFT)
215 #endif
216 
217 /*
218  * btodb() is messy and perhaps slow because `bytes' may be an off_t.  We
219  * want to shift an unsigned type to avoid sign extension and we don't
220  * want to widen `bytes' unnecessarily.  Assume that the result fits in
221  * a daddr_t.
222  */
223 #ifndef btodb
224 #define btodb(bytes)	 		/* calculates (bytes / DEV_BSIZE) */ \
225 	(sizeof (bytes) > sizeof(long) \
226 	 ? (daddr_t)((unsigned long long)(bytes) >> DEV_BSHIFT) \
227 	 : (daddr_t)((unsigned long)(bytes) >> DEV_BSHIFT))
228 #endif
229 
230 #ifndef dbtob
231 #define dbtob(db)			/* calculates (db * DEV_BSIZE) */ \
232 	((off_t)(db) << DEV_BSHIFT)
233 #endif
234 
235 #define	PRIMASK		0x0ff
236 #define	PCATCH		0x100	/* OR'd with pri for tsleep to check signals */
237 #define	PDROP		0x200	/* OR'd with pri to stop re-entry of interlock mutex */
238 #define	PNOLOCK		0x400	/* OR'd with pri to allow sleeping w/o a lock */
239 #define	PRILASTFLAG	0x400	/* Last flag defined above */
240 
241 #define	NZERO	0		/* default "nice" */
242 
243 #define	NBBY	8		/* number of bits in a byte */
244 #define	NBPW	sizeof(int)	/* number of bytes per word (integer) */
245 
246 #define	CMASK	022		/* default file mask: S_IWGRP|S_IWOTH */
247 
248 #define	NODEV	(dev_t)(-1)	/* non-existent device */
249 
250 /*
251  * File system parameters and macros.
252  *
253  * MAXBSIZE -	Filesystems are made out of blocks of at most MAXBSIZE bytes
254  *		per block.  MAXBSIZE may be made larger without effecting
255  *		any existing filesystems as long as it does not exceed MAXPHYS,
256  *		and may be made smaller at the risk of not being able to use
257  *		filesystems which require a block size exceeding MAXBSIZE.
258  *
259  * MAXBCACHEBUF - Maximum size of a buffer in the buffer cache.  This must
260  *		be >= MAXBSIZE and can be set differently for different
261  *		architectures by defining it in <machine/param.h>.
262  *		Making this larger allows NFS to do larger reads/writes.
263  *
264  * BKVASIZE -	Nominal buffer space per buffer, in bytes.  BKVASIZE is the
265  *		minimum KVM memory reservation the kernel is willing to make.
266  *		Filesystems can of course request smaller chunks.  Actual
267  *		backing memory uses a chunk size of a page (PAGE_SIZE).
268  *		The default value here can be overridden on a per-architecture
269  *		basis by defining it in <machine/param.h>.
270  *
271  *		If you make BKVASIZE too small you risk seriously fragmenting
272  *		the buffer KVM map which may slow things down a bit.  If you
273  *		make it too big the kernel will not be able to optimally use
274  *		the KVM memory reserved for the buffer cache and will wind
275  *		up with too-few buffers.
276  *
277  *		The default is 16384, roughly 2x the block size used by a
278  *		normal UFS filesystem.
279  */
280 #define MAXBSIZE	65536	/* must be power of 2 */
281 #ifndef	MAXBCACHEBUF
282 #define	MAXBCACHEBUF	MAXBSIZE /* must be a power of 2 >= MAXBSIZE */
283 #endif
284 #ifndef	BKVASIZE
285 #define BKVASIZE	16384	/* must be power of 2 */
286 #endif
287 #define BKVAMASK	(BKVASIZE-1)
288 
289 /*
290  * MAXPATHLEN defines the longest permissible path length after expanding
291  * symbolic links. It is used to allocate a temporary buffer from the buffer
292  * pool in which to do the name expansion, hence should be a power of two,
293  * and must be less than or equal to MAXBSIZE.  MAXSYMLINKS defines the
294  * maximum number of symbolic links that may be expanded in a path name.
295  * It should be set high enough to allow all legitimate uses, but halt
296  * infinite loops reasonably quickly.
297  */
298 #define	MAXPATHLEN	PATH_MAX
299 #define MAXSYMLINKS	32
300 
301 /* Bit map related macros. */
302 #define	setbit(a,i)	(((unsigned char *)(a))[(i)/NBBY] |= 1<<((i)%NBBY))
303 #define	clrbit(a,i)	(((unsigned char *)(a))[(i)/NBBY] &= ~(1<<((i)%NBBY)))
304 #define	isset(a,i)							\
305 	(((const unsigned char *)(a))[(i)/NBBY] & (1<<((i)%NBBY)))
306 #define	isclr(a,i)							\
307 	((((const unsigned char *)(a))[(i)/NBBY] & (1<<((i)%NBBY))) == 0)
308 
309 /* Macros for counting and rounding. */
310 #ifndef howmany
311 #define	howmany(x, y)	(((x)+((y)-1))/(y))
312 #endif
313 #define	nitems(x)	(sizeof((x)) / sizeof((x)[0]))
314 #define	rounddown(x, y)	(((x)/(y))*(y))
315 #define	rounddown2(x, y) __align_down(x, y) /* if y is power of two */
316 #define	roundup(x, y)	((((x)+((y)-1))/(y))*(y))  /* to any y */
317 #define	roundup2(x, y)	__align_up(x, y) /* if y is powers of two */
318 #define powerof2(x)	((((x)-1)&(x))==0)
319 
320 /* Macros for min/max. */
321 #define	MIN(a,b) (((a)<(b))?(a):(b))
322 #define	MAX(a,b) (((a)>(b))?(a):(b))
323 
324 #ifdef _KERNEL
325 /*
326  * Basic byte order function prototypes for non-inline functions.
327  */
328 #ifndef LOCORE
329 #ifndef _BYTEORDER_PROTOTYPED
330 #define	_BYTEORDER_PROTOTYPED
331 __BEGIN_DECLS
332 __uint32_t	 htonl(__uint32_t);
333 __uint16_t	 htons(__uint16_t);
334 __uint32_t	 ntohl(__uint32_t);
335 __uint16_t	 ntohs(__uint16_t);
336 __END_DECLS
337 #endif
338 #endif
339 
340 #ifndef _BYTEORDER_FUNC_DEFINED
341 #define	_BYTEORDER_FUNC_DEFINED
342 #define	htonl(x)	__htonl(x)
343 #define	htons(x)	__htons(x)
344 #define	ntohl(x)	__ntohl(x)
345 #define	ntohs(x)	__ntohs(x)
346 #endif /* !_BYTEORDER_FUNC_DEFINED */
347 #endif /* _KERNEL */
348 
349 /*
350  * Scale factor for scaled integers used to count %cpu time and load avgs.
351  *
352  * The number of CPU `tick's that map to a unique `%age' can be expressed
353  * by the formula (1 / (2 ^ (FSHIFT - 11))).  Since the intermediate
354  * calculation is done with 64-bit precision, the maximum load average that can
355  * be calculated is approximately 2^32 / FSCALE.
356  *
357  * For the scheduler to maintain a 1:1 mapping of CPU `tick' to `%age',
358  * FSHIFT must be at least 11.  This gives a maximum load avg of 2 million.
359  */
360 #define	FSHIFT	11		/* bits to right of fixed binary point */
361 #define FSCALE	(1<<FSHIFT)
362 
363 #define dbtoc(db)			/* calculates devblks to pages */ \
364 	((db + (ctodb(1) - 1)) >> (PAGE_SHIFT - DEV_BSHIFT))
365 
366 #define ctodb(db)			/* calculates pages to devblks */ \
367 	((db) << (PAGE_SHIFT - DEV_BSHIFT))
368 
369 /*
370  * Old spelling of __containerof().
371  */
372 #define	member2struct(s, m, x)						\
373 	((struct s *)(void *)((char *)(x) - offsetof(struct s, m)))
374 
375 /*
376  * Access a variable length array that has been declared as a fixed
377  * length array.
378  */
379 #define __PAST_END(array, offset) (((__typeof__(*(array)) *)(array))[offset])
380 
381 #endif	/* _SYS_PARAM_H_ */
382