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  * 3. 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: src/sys/sys/param.h,v 1.61.2.38 2003/05/22 17:12:01 fjoe Exp $
  36  */
  37
  38 #ifndef _SYS_PARAM_H_
  39 #define _SYS_PARAM_H_
  40
  41 /*
  42  * Historic BSD #defines -- probably will remain untouched for all time.
  43  */
  44 #define BSD     199506          /* System version (year & month). */
  45 #define BSD4_3  1
  46 #define BSD4_4  1
  47
  48 /*
  49  * __DragonFly_version number.  The number doesn't really meaningfully
  50  * translate to a version number.
  51  *
  52  * 170000 - base development version after 1.6 branch
  53  * 170001 - base development version before 1.8 branch
  54  * 190000 - base development version after 1.8 branch
  55  * 195000 - base development version after 1.10 branch
  56  * 197500 - base development version before 1.12 branch
  57  * 197600 - 1.12 branch
  58  * 197700 - base development version after 1.12 branch
  59  * 199900 - base development version before 2.0 branch
  60  * 200000 - 2.0 branch
  61  * 200100 - base development version after 2.0 branch
  62  * 200101 - lchflags syscall
  63  * 200200 - 2.2 branch
  64  * 200201 - base development version after 2.2 branch
  65  * 200202 - major changes to libc
  66  * 200203 - introduce PCI domain
  67  * 200204 - suser() & suser_cred() removal
  68  * 200205 - devfs import
  69  * 200206 - *sleep() renames
  70  * 200400 - 2.4 release
  71  * 200500 - 2.5 master
  72  * 200600 - 2.6 release
  73  * 200700 - 2.7 master
  74  * 200800 - 2.8 release                 October 2010
  75  * 200900 - 2.9 master
  76  * 200901 - prototype changes for alphasort(3) and scandir(3)
  77  * 200902 - Xerox NS protocol removal
  78  * 201000 - 2.10 release
  79  * 201100 - 2.11 master
  80  * 201200 - 2.12 release
  81  * 201300 - 2.13 master
  82  * 201301 - header rename: <vfs/gnu/ext2fs/...> -> <gnu/vfs/ext2fs/...>
  83  * 201302 - header <crypt.h> is gone
  84  * 201303 - <netatalk/...> and <netproto/atalk/...> are gone
  85  * 201304 - Added wcscasecmp, wcsncasecmp to libc
  86  * 201305 - Sync libm with NetBSD-current libm (new functions added)
  87  * 201306 - Sync libm with FreeBSD-current libm (~50 new functions)
  88  * 300000 - 3.0 release
  89  * 300100 - 3.1 master
  90  * 300101 - i4b (ISDN) removal
  91  * 300102 - <sys/ata.h> is now just a link of <sys/nata.h>
  92  * 300103 - if SIG_IGN is set on SIGCHLD, do not keep zombie children
  93  * 300200 - 3.2 release
  94  * 300300 - 3.3 master
  95  * 300301 - Add eaccess syscall
  96  * 300302 - fpsave changes - ucontext_t, mcontext_t, sigcontext, sigframe
  97  * 300303 - Demarcation of old m4/flex with new m4/flex
  98  * 300304 - Update to dialog-1.2-20121230
  99  * 300400 - 3.4 release
 100  * 300500 - 3.5 master
 101  * 300501 - Convert libm to FreeBSD's version
 102  * 300502 - GEM and i915 KMS support in kernel
 103  * 300503 - Upgrade libiconv, locales, and associated libc functions
 104  * 300600 - 3.6 release
 105  * 300700 - 3.7 master
 106  * 300701 - Relocate bus/smbus/smb.h to dev/smbus/smb/smb.h
 107  * 300702 - drm/i915 update
 108  * 300703 - Make usb4bsd default
 109  * 300704 - Removal of IPX, NCP and NWFS support
 110  * 300705 - Removal of ATM support.
 111  * 300800 - 3.8 release
 112  * 300900 - 3.9 master
 113  * 300901 - drm/i915 hardware context support added
 114  * 400000 - 4.0 release
 115  * 400100 - 4.1 development
 116  * 400101 - Removal of SCTP support.
 117  * 400102 - Sound system update from FreeBSD
 118  * 400103 - Milestone - availability of gcc50 in base
 119  * 400104 - struct lwp_params (a public struct) members renaming
 120  * 400105 - Switch to gcc50 as the primary compiler
 121  * 400106 - Added pipe2() system call
 122  * 400107 - Add futimens() and utimensat() syscalls
 123  * 400200 - 4.2 release
 124  * 400300 - 4.3 development
 125  * 400301 - posix compliant iconv (no const qualifier)
 126  * 400302 - Replacement of libm with OpenBSD's libm
 127  * 400303 - environ and __progname are no longer linkable symbols
 128  * 400304 - Activate symbol versioning for libc.so (still on version 8)
 129  * 400305 - Add accept4() system call
 130  * 400306 - Add libexecinfo to base
 131  * 400307 - drm/i915 kernel module renamed to i915.ko
 132  * 400308 - <malloc.h> removal
 133  * 400309 - Add lwp_setname() system call
 134  * 400400 - 4.4 release
 135  * 400500 - 4.5 development
 136  * 400501 - unionfs removal
 137  * 400502 - private libraries: ssh ldns edit ncurses
 138  * 400503 - libarchive-3.0.2 import (add bsdcat)
 139  * 400600 - 4.6 release
 140  * 400700 - 4.7 development
 141  * 400701 - getline() visibility changes
 142  * 400702 - private library: libressl
 143  * 400703 - resolved conflicts of md, crypt and ressl libraries
 144  * 400704 - binutils update to 2.27
 145  * 400705 - lwp_{set,get}affinity()
 146  * 400706 - sched_{set,get}affinity()
 147  * 400707 - pthread_{set,get}affinity_np()
 148  * 400708 - lwp_create2()
 149  * 400709 - pthread_attr_{set,get}affinity_np()
 150  * 400710 - sched_getcpu();
 151  * 400711 - move lwp syscalls to sys/lwp.h
 152  * 400712 - restore lwp syscalls (except lwp_create*) declaration
 153  * 400713 - add sysctl kern.cp_times
 154  * 400800 - 4.8 release
 155  * 400900 - 4.9 development
 156  * 400901 - moved sigtramp, NX protection, sigtramp sysctl
 157  * 400902 - change CPU_SETSIZE to signed; allow proc to change self affinity
 158  * 400903 - malloc_type cleanup
 159  * 400904 - pad rtstatistics
 160  * 400905 - PTHREAD_STACK_MIN increase: 1024 => 16384
 161  * 400906 - lwpid_t >=1, instead of >=0
 162  * 400907 - pthread_getthreadid_np()
 163  * 400908 - {clock,pthread}_getcpuclockid()
 164  * 400909 - deleted ortentry, SIOC{ADD,DEL}RT, RTM_OLD{ADD,DEL}
 165  * 400910 - routing table is only available on netisr_ncpus
 166  * 500000 - 5.0 release
 167  * 500100 - 5.1 development
 168  * 500101 - kernel ppp removal
 169  * 500102 - <sys/sysref{,2}.h> inclusions removed from some public headers
 170  * 500103 - faith removal
 171  * 500104 - cfmakesane()
 172  * 500105 - _SC_LEVEL1_DCACHE_LINESIZE sysconf()
 173  * 500106 - %b and %r formats removal
 174  * 500107 - <machine/apm_bios.h> removal
 175  * 500200 - 5.2 release
 176  * 500300 - 5.3 development
 177  * 500301 - rename some public UFS constants
 178  * 500302 - move IOCTLTRIM to a better header and rename it to DAIOCTRIM
 179  * 500303 - get rid of sgtty (superseded by termios)
 180  * 500304 - remove IPSEC/FAST_IPSEC
 181  * 500305 - remove <sys/ioctl_compat.h> for good
 182  * 500306 - strsuftoll(), strsuftollx()
 183  * 500307 - tcsetsid()
 184  * 500308 - xdr_uint16_t()
 185  * 500309 - drop support for some ancient ioctls (OSIOCGIF*)
 186  * 500310 - remove more unimplemented ioctls
 187  * 500311 - add VIS_ALL to vis(3)
 188  * 500312 - OpenPAM Resedacea upgrade
 189  * 500313 - remove vmnet support from tap(4) (VMIO_* ioctls)
 190  * 500314 - add TAPGIFNAME to tap(4)
 191  * 500315 - add TUNGIFNAME to tun(4)
 192  * 500316 - add SIOC[ADG]IFGROUP, SIOCGIFGMEMB ioctl
 193  * 500317 - add wait6() and waitid() syscalls
 194  * 500400 - 5.4 release
 195  * 500500 - 5.5 development
 196  * 500501 - reallocarray() added to libc
 197  * 500502 - puffs etc. removed
 198  * 500503 - Lowered DATA rlimit supported by mmap(), libc sbrk() emulation
 199  *          had to be rewritten.  libc brk() removed entirely.  These changes
 200  *          are required to allow mmap hints to utilize lowered data rlimits.
 201  * 500504 - removed <sys/semaphore.h>, only <semaphore.h> remains
 202  * 500505 - rename <sys/termios.h> to <termios.h>
 203  * 500506 - LibreSSL, OpenSSH, XZ, libarchive update, libopie/libmd deprecation
 204  * 500600 - 5.6 release
 205  * 500700 - 5.7 development
 206  * 500701 - libopie/libmd removal
 207  * 500702 - TCP_KEEP* milliseconds -> seconds
 208  * 500703 - Static TLS bindings support for late-loaded shared libraries
 209  * 500704 - Announce IP6 address flag changes via route(4)
 210  * 500705 - Move us to utmpx only, delete utmp
 211  * 500706 - Switch to the now common three argument versions of the
 212  *          timespecadd() and timespecsub() macros in <sys/time.h>
 213  * 500707 - libradius/libtacplus removal
 214  * 500708 - Handle SIOCSIFMTU directly in tap(4) to support MTU > 1500
 215  * 500709 - Implement lwp_getname() and signal safety
 216  * 500710 - Implement getrandom() and __realpath() system calls
 217  * 500800 - 5.8 release
 218  * 500900 - 5.9 development
 219  * 500901 - fparseln() was moved from libutil to libc
 220  * 500902 - unlocked flavors of fflush(), fputc(), fputs(), fread(), fwrite()
 221  * 500903 - add SIOCGIFXMEDIA ioctl
 222  * 500904 - add IPPROTO_IP/IP_RECVTOS.
 223  * 500905 - add IPPROTO_IP/IP_SENDSRCADDR and IP_TOS control message.
 224  * 500906 - add struct ip_mreqn for IPPROTO_IP/IP_MULTICAST_IF,
 225  *          IP_ADD_MEMBERSHIP and IP_DROP_MEMBERSHIP.
 226  * 500907 - add clock_nanosleep()
 227  * 500908 - add fexecve() (also byteswap.h exists as of this vers)
 228  * 500909 - add AF_ARP
 229  * 600000 - 6.0 release
 230  * 600100 - 6.1 development
 231  * 600101 - kernel_{map,pmap,object} and {buffer,clean,pager}_map globals
 232  *          become pointers
 233  * 600102 - add nvmm(4) and libnvmm(3)
 234  * 600103 - remove the old vmm code
 235  * 600104 - add posix_fallocate()
 236  * 600105 - add fdatasync()
 237  * 600106 - msdosfs support in makefs(8)
 238  * 600107 - remove sys/gnu/vfs/ext2fs
 239  * 600200 - 6.2 release
 240  * 600300 - 6.3 development
 241  * 600301 - add strerror_l()
 242  * 600302 - change sysctl KERN_PROC behavior
 243  * 600400 - 6.4 release
 244  * 600500 - 6.5 development
 245  * 600501 - add fopencookie(3)
 246  * 600502 - WIFSIGNALED(x) excludes SIGCONT
 247  * 600503 - kldstat(2) supports module's full path
 248  * 600504 - change m_copyback(9) to forbid mbuf expansion
 249  * 600505 - add SO_USER_COOKIE to setsockopt(2)/getsockopt(2)
 250  * 600506 - add mbuf m_pkthdr.loop_cnt for loop detection
 251  * 600507 - remove mbuf m_pkthdr.loop_cnt and replace with
 252  *          if_tunnel_check_nesting()
 253  * 600508 - add ND6_IFF_AUTO_LINKLOCAL and ND6_IFF_NO_DAD;
 254  *          change ip6.accept_rtadv and ip6.auto_linklocal behavior
 255  */
 256 #undef __DragonFly_version
 257 #define __DragonFly_version 600508      /* propagated to newvers */
 258
 259 #include <sys/_null.h>
 260
 261 #ifndef LOCORE
 262 #include <sys/types.h>
 263 #endif
 264
 265 /*
 266  * Machine-independent constants (some used in following include files).
 267  * Redefined constants are from POSIX 1003.1 limits file.
 268  *
 269  * MAXCOMLEN should be >= sizeof(ac_comm) (see <acct.h>)
 270  */
 271 #include <sys/syslimits.h>
 272
 273 #define MAXCOMLEN       16              /* max command name remembered */
 274 #define MAXINTERP       32              /* max interpreter file name length */
 275 #define MAXLOGNAME      33              /* max login name length (incl. NUL) */
 276 #define MAXUPRC         CHILD_MAX       /* max simultaneous processes */
 277 #define NCARGS          ARG_MAX         /* max bytes for an exec function */
 278 #define NGROUPS         NGROUPS_MAX     /* max number groups */
 279 #define NOFILE          OPEN_MAX        /* max open files per process */
 280 #define NOGROUP         65535           /* marker for empty group set member */
 281 #define MAXHOSTNAMELEN  256             /* max hostname size */
 282 #define SPECNAMELEN     63              /* max length of devicename */
 283
 284 /* More types and definitions used throughout the kernel. */
 285 #ifdef _KERNEL
 286 #include <sys/cdefs.h>
 287 #include <sys/errno.h>
 288 #include <sys/time.h>
 289
 290 #define FALSE   0
 291 #define TRUE    1
 292 #endif
 293
 294 #ifndef _KERNEL
 295 /* Signals. */
 296 #include <sys/select.h>
 297 #include <sys/signal.h>
 298 #endif
 299
 300 /* Machine type dependent parameters. */
 301 #include <machine/alignbytes.h>
 302 #include <machine/param.h>
 303 #ifndef _KERNEL
 304 #include <machine/limits.h>
 305 #endif
 306
 307 /*
 308  * WARNING! Max supported cpu's due to PWAKEUP_CPUMASK is 16384.
 309  */
 310 #define PCATCH          0x00000100      /* tsleep checks signals */
 311 #define PUSRFLAG1       0x00000200      /* Subsystem specific flag */
 312 #define PINTERLOCKED    0x00000400      /* Interlocked tsleep */
 313 #define PWAKEUP_CPUMASK 0x00003FFF      /* start cpu for chained wakeups */
 314 #define PWAKEUP_MYCPU   0x00004000      /* wakeup on current cpu only */
 315 #define PWAKEUP_ONE     0x00008000      /* argument to wakeup: only one */
 316 #define PDOMAIN_MASK    0xFFFF0000      /* address domains for wakeup */
 317 #define PDOMAIN_UMTX    0x00010000      /* independant domain for UMTX */
 318 #define PDOMAIN_XLOCK   0x00020000      /* independant domain for fifo_lock */
 319 #define PDOMAIN_FBSD0   0x01000000      /* freebsd sleepq queues */
 320 #define PDOMAIN_FBSDINC 0x00010000      /* freebsd sleepq queue 1 */
 321 #define PWAKEUP_ENCODE(domain, cpu)     ((domain) | (cpu))
 322 #define PWAKEUP_DECODE(domain)          ((domain) & PWAKEUP_CPUMASK)
 323
 324 #define NZERO   0               /* default "nice" */
 325
 326 #define NBBY    8               /* number of bits in a byte */
 327 #define NBPW    sizeof(int)     /* number of bytes per word (integer) */
 328
 329 #define CMASK   022             /* default file mask: S_IWGRP|S_IWOTH */
 330 #if defined(_KERNEL) || defined(_KERNEL_STRUCTURES)
 331 #define NOUDEV  (dev_t)(-1)     /* non-existent device */
 332 #define NOMAJ   256             /* non-existent device */
 333 #endif
 334
 335 #ifndef _KERNEL
 336 #define NODEV   (dev_t)(-1)     /* non-existent device */
 337 #endif
 338
 339 /*
 340  * cpu_mi_feature bits
 341  */
 342 #define CPU_MI_BZERONT  0x00000001
 343 #define CPU_MI_MONITOR  0x00000010
 344
 345 /*
 346  * File system parameters and macros.
 347  *
 348  * MAXBSIZE -   Filesystems are made out of blocks of at most MAXBSIZE bytes
 349  *              per block.  MAXBSIZE may be made larger without effecting
 350  *              any existing filesystems as long as it does not exceed MAXPHYS,
 351  *              and may be made smaller at the risk of not being able to use
 352  *              filesystems which require a block size exceeding MAXBSIZE.
 353  *
 354  * NBUFCALCSIZE - Calculate sufficient buffer cache buffers for the memory
 355  *              desired as if each buffer were sized to this value (actual
 356  *              real memory use).  Hysteresis works both ways.
 357  */
 358 #define MAXBSIZE        65536           /* must be power of 2 */
 359 #define NBUFCALCSIZE    16384           /* for nbuf calculation only */
 360
 361 #define MAXFRAG         8
 362
 363 /*
 364  * MAXPATHLEN defines the longest permissible path length after expanding
 365  * symbolic links. It is used to allocate a temporary buffer from the buffer
 366  * pool in which to do the name expansion, hence should be a power of two,
 367  * and must be less than or equal to MAXBSIZE.  MAXSYMLINKS defines the
 368  * maximum number of symbolic links that may be expanded in a path name.
 369  * It should be set high enough to allow all legitimate uses, but halt
 370  * infinite loops reasonably quickly.
 371  */
 372 #define MAXPATHLEN      PATH_MAX
 373 #define MAXSYMLINKS     32
 374
 375 /* Bit map related macros. */
 376 #define setbit(a,i)     ((a)[(i)/NBBY] |= 1<<((i)%NBBY))
 377 #define clrbit(a,i)     ((a)[(i)/NBBY] &= ~(1<<((i)%NBBY)))
 378 #define isset(a,i)      ((a)[(i)/NBBY] & (1<<((i)%NBBY)))
 379 #define isclr(a,i)      (((a)[(i)/NBBY] & (1<<((i)%NBBY))) == 0)
 380
 381 /* Macros for counting and rounding. */
 382 #ifndef howmany
 383 #define howmany(x, y)   (((x)+((y)-1))/(y))
 384 #endif
 385 #define nitems(x)       NELEM(x)
 386 #define rounddown(x, y) (((x)/(y))*(y))
 387 #define rounddown2(x, y) ((x) & ~((y) - 1))        /* y power of two */
 388 #define roundup(x, y)   ((((x)+((y)-1))/(y))*(y))  /* to any y */
 389 #define roundup2(x, y)  (((x)+((y)-1))&(~((y)-1))) /* if y is powers of two */
 390 #define powerof2(x)     ((((x)-1)&(x))==0)
 391
 392 /*
 393  * VM objects can be larger than the virtual address space, make sure
 394  * we don't cut-off the mask.
 395  */
 396 #define trunc_page64(x)           ((x) & ~(int64_t)PAGE_MASK)
 397 #define round_page64(x)           (((x) + PAGE_MASK) & ~(int64_t)PAGE_MASK)
 398
 399 /*
 400  * Round p (pointer or byte index) up to a correctly-aligned value
 401  * for all data types (int, long, ...).   The result is unsigned int
 402  * and must be cast to any desired pointer type.  Single underscore
 403  * versions are for FreeBSD/OpenBSD compat.
 404  */
 405 #define _ALIGNBYTES     __ALIGNBYTES
 406 #define _ALIGN(p)       __ALIGNPTR(p)
 407 #ifndef ALIGNBYTES
 408 #define ALIGNBYTES      __ALIGNBYTES
 409 #endif
 410 #ifndef ALIGN
 411 #define ALIGN(p)        __ALIGNPTR(p)
 412 #endif
 413
 414 /* Macros for min/max. */
 415 #define MIN(a,b) (((a)<(b))?(a):(b))
 416 #define MAX(a,b) (((a)>(b))?(a):(b))
 417
 418 /* Macro for array size */
 419 #define NELEM(ary)      (sizeof(ary) / sizeof((ary)[0]))
 420
 421 /*
 422  * Constants for setting the parameters of the kernel memory allocator.
 423  *
 424  * 2 ** MINBUCKET is the smallest unit of memory that will be
 425  * allocated. It must be at least large enough to hold a pointer.
 426  *
 427  * Units of memory less or equal to MAXALLOCSAVE will permanently
 428  * allocate physical memory; requests for these size pieces of
 429  * memory are quite fast. Allocations greater than MAXALLOCSAVE must
 430  * always allocate and free physical memory; requests for these
 431  * size allocations should be done infrequently as they will be slow.
 432  *
 433  * Constraints: PAGE_SIZE <= MAXALLOCSAVE <= 2 ** (MINBUCKET + 14), and
 434  * MAXALLOCSIZE must be a power of two.
 435  */
 436 #define MINBUCKET       4               /* 4 => min allocation of 16 bytes */
 437 #define MAXALLOCSAVE    (2 * PAGE_SIZE)
 438
 439 /*
 440  * Scale factor for scaled integers used to count %cpu time and load avgs.
 441  *
 442  * The number of CPU `tick's that map to a unique `%age' can be expressed
 443  * by the formula (1 / (2 ^ (FSHIFT - 11))).  The maximum load average that
 444  * can be calculated (assuming 32 bits) can be closely approximated using
 445  * the formula (2 ^ (2 * (16 - FSHIFT))) for (FSHIFT < 15).
 446  *
 447  * For the scheduler to maintain a 1:1 mapping of CPU `tick' to `%age',
 448  * FSHIFT must be at least 11; this gives us a maximum load avg of ~1024.
 449  */
 450 #define FSHIFT  11              /* bits to right of fixed binary point */
 451 #define FSCALE  (1<<FSHIFT)
 452
 453 #define dbtoc(db)                       /* calculates devblks to pages */ \
 454         ((db + (ctodb(1) - 1)) >> (PAGE_SHIFT - DEV_BSHIFT))
 455
 456 #define ctodb(db)                       /* calculates pages to devblks */ \
 457         ((db) << (PAGE_SHIFT - DEV_BSHIFT))
 458
 459 #define MJUMPAGESIZE    PAGE_SIZE       /* jumbo cluster 4k */
 460 #define MJUM9BYTES      (9 * 1024)      /* jumbo cluster 9k */
 461 #define MJUM16BYTES     (16 * 1024)     /* jumbo cluster 16k */
 462
 463 /*
 464  * MBUF Management.
 465  *
 466  * Because many drivers can't deal with multiple DMA segments all mbufs
 467  * must avoid crossing a page boundary.  While we can accomodate mbufs
 468  * which are not a power-of-2 sized kmalloc() will only guarantee
 469  * non-crossing alignment if we use a power-of-2.  256 is no longer large
 470  * enough due to m_hdr and m_pkthdr bloat.
 471  *
 472  * MCLBYTES must be a power of 2 and is typically significantly larger
 473  * than MSIZE, sufficient to hold a standard-mtu packet.  2K is considered
 474  * reasonable.
 475  */
 476 #ifndef MSIZE
 477 #define MSIZE           512             /* size of an mbuf */
 478 #endif
 479
 480 #ifndef MCLSHIFT
 481 #define MCLSHIFT        11              /* convert bytes to m_buf clusters */
 482 #endif
 483 #define MCLBYTES        (1 << MCLSHIFT) /* size of an m_buf cluster */
 484 #define MCLOFSET        (MCLBYTES - 1)  /* offset within an m_buf cluster */
 485
 486 /*
 487  * Make this available for most of the kernel.  There were too many
 488  * things that included sys/systm.h just for panic().
 489  */
 490 #ifdef _KERNEL
 491 void    panic (const char *, ...) __dead2 __printflike(1, 2);
 492 #endif
 493
 494 #ifndef _BYTEORDER_FUNC_DEFINED
 495 #define _BYTEORDER_FUNC_DEFINED
 496 #define htonl(x)        __htonl(x)
 497 #define htons(x)        __htons(x)
 498 #define ntohl(x)        __ntohl(x)
 499 #define ntohs(x)        __ntohs(x)
 500 #endif
 501
 502 /*
 503  * Access a variable length array that has been declared as a fixed
 504  * length array.
 505  */
 506 #define __PAST_END(array, offset) (((__typeof__(*(array)) *)(array))[offset])
 507
 508 #endif  /* _SYS_PARAM_H_ */