kern_subr.c

Version: - FREEBSD - FREEBSD-13-STABLE - FREEBSD-13-0 - FREEBSD-12-STABLE - FREEBSD-12-0 - FREEBSD-11-STABLE - FREEBSD-11-0 - FREEBSD-10-STABLE - FREEBSD-10-0 - FREEBSD-9-STABLE - FREEBSD-9-0 - FREEBSD-8-STABLE - FREEBSD-8-0 - FREEBSD-7-STABLE - FREEBSD-7-0 - FREEBSD-6-STABLE - FREEBSD-6-0 - FREEBSD-5-STABLE - FREEBSD-5-0 - FREEBSD-4-STABLE - FREEBSD-3-STABLE - FREEBSD22 - l41 - OPENBSD - linux-2.6 - MK84 - PLAN9 - xnu-8792
SearchContext: - none - 3 - 10
    1 /*
    2  * Copyright (c) 1982, 1986, 1991, 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. All advertising materials mentioning features or use of this software
   19  *    must display the following acknowledgement:
   20  *      This product includes software developed by the University of
   21  *      California, Berkeley and its contributors.
   22  * 4. Neither the name of the University nor the names of its contributors
   23  *    may be used to endorse or promote products derived from this software
   24  *    without specific prior written permission.
   25  *
   26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   36  * SUCH DAMAGE.
   37  *
   38  *      @(#)kern_subr.c 8.3 (Berkeley) 1/21/94
   39  */
   40 
   41 #include <sys/cdefs.h>
   42 __FBSDID("$FreeBSD: releng/5.2/sys/kern/kern_subr.c 120665 2003-10-02 15:00:55Z nectar $");
   43 
   44 #include "opt_zero.h"
   45 
   46 #include <sys/param.h>
   47 #include <sys/systm.h>
   48 #include <sys/kernel.h>
   49 #include <sys/ktr.h>
   50 #include <sys/limits.h>
   51 #include <sys/lock.h>
   52 #include <sys/mutex.h>
   53 #include <sys/proc.h>
   54 #include <sys/malloc.h>
   55 #include <sys/resourcevar.h>
   56 #include <sys/sched.h>
   57 #include <sys/sysctl.h>
   58 #include <sys/vnode.h>
   59 
   60 #include <vm/vm.h>
   61 #include <vm/vm_page.h>
   62 #include <vm/vm_map.h>
   63 #ifdef ZERO_COPY_SOCKETS
   64 #include <vm/vm_param.h>
   65 #include <vm/vm_object.h>
   66 #endif
   67 
   68 SYSCTL_INT(_kern, KERN_IOV_MAX, iov_max, CTLFLAG_RD, NULL, UIO_MAXIOV,
   69         "Maximum number of elements in an I/O vector; sysconf(_SC_IOV_MAX)");
   70 
   71 #ifdef ZERO_COPY_SOCKETS
   72 /* Declared in uipc_socket.c */
   73 extern int so_zero_copy_receive;
   74 
   75 static int
   76 vm_pgmoveco(vm_map_t mapa, vm_object_t srcobj, vm_offset_t kaddr,
   77     vm_offset_t uaddr)
   78 {
   79         vm_map_t map = mapa;
   80         vm_page_t kern_pg, user_pg;
   81         vm_object_t uobject;
   82         vm_map_entry_t entry;
   83         vm_pindex_t upindex, kpindex;
   84         vm_prot_t prot;
   85         boolean_t wired;
   86 
   87         /*
   88          * First lookup the kernel page.
   89          */
   90         kern_pg = PHYS_TO_VM_PAGE(vtophys(kaddr));
   91         /*
   92          * XXX The vm object containing kern_pg needs locking.
   93          */
   94         if ((vm_map_lookup(&map, uaddr,
   95                            VM_PROT_WRITE, &entry, &uobject,
   96                            &upindex, &prot, &wired)) != KERN_SUCCESS) {
   97                 return(EFAULT);
   98         }
   99         VM_OBJECT_LOCK(uobject);
  100         if ((user_pg = vm_page_lookup(uobject, upindex)) != NULL) {
  101                 do
  102                         vm_page_lock_queues();
  103                 while (vm_page_sleep_if_busy(user_pg, 1, "vm_pgmoveco"));
  104                 vm_page_busy(user_pg);
  105                 pmap_remove_all(user_pg);
  106                 vm_page_free(user_pg);
  107         } else
  108                 vm_page_lock_queues();
  109         if (kern_pg->busy || ((kern_pg->queue - kern_pg->pc) == PQ_FREE) ||
  110             (kern_pg->hold_count != 0)|| (kern_pg->flags & PG_BUSY)) {
  111                 printf("vm_pgmoveco: pindex(%lu), busy(%d), PG_BUSY(%d), "
  112                        "hold(%d) paddr(0x%lx)\n", (u_long)kern_pg->pindex,
  113                         kern_pg->busy, (kern_pg->flags & PG_BUSY) ? 1 : 0,
  114                         kern_pg->hold_count, (u_long)kern_pg->phys_addr);
  115                 if ((kern_pg->queue - kern_pg->pc) == PQ_FREE)
  116                         panic("vm_pgmoveco: renaming free page");
  117                 else
  118                         panic("vm_pgmoveco: renaming busy page");
  119         }
  120         kpindex = kern_pg->pindex;
  121         vm_page_busy(kern_pg);
  122         vm_page_rename(kern_pg, uobject, upindex);
  123         vm_page_flag_clear(kern_pg, PG_BUSY);
  124         kern_pg->valid = VM_PAGE_BITS_ALL;
  125         vm_page_unlock_queues();
  126         VM_OBJECT_UNLOCK(uobject);
  127         vm_map_lookup_done(map, entry);
  128         return(KERN_SUCCESS);
  129 }
  130 #endif /* ZERO_COPY_SOCKETS */
  131 
  132 int
  133 uiomove(void *cp, int n, struct uio *uio)
  134 {
  135         struct thread *td = curthread;
  136         struct iovec *iov;
  137         u_int cnt;
  138         int error = 0;
  139         int save = 0;
  140 
  141         KASSERT(uio->uio_rw == UIO_READ || uio->uio_rw == UIO_WRITE,
  142             ("uiomove: mode"));
  143         KASSERT(uio->uio_segflg != UIO_USERSPACE || uio->uio_td == curthread,
  144             ("uiomove proc"));
  145 
  146         if (td) {
  147                 mtx_lock_spin(&sched_lock);
  148                 save = td->td_flags & TDF_DEADLKTREAT;
  149                 td->td_flags |= TDF_DEADLKTREAT;
  150                 mtx_unlock_spin(&sched_lock);
  151         }
  152 
  153         while (n > 0 && uio->uio_resid) {
  154                 iov = uio->uio_iov;
  155                 cnt = iov->iov_len;
  156                 if (cnt == 0) {
  157                         uio->uio_iov++;
  158                         uio->uio_iovcnt--;
  159                         continue;
  160                 }
  161                 if (cnt > n)
  162                         cnt = n;
  163 
  164                 switch (uio->uio_segflg) {
  165 
  166                 case UIO_USERSPACE:
  167                         if (ticks - PCPU_GET(switchticks) >= hogticks)
  168                                 uio_yield();
  169                         if (uio->uio_rw == UIO_READ)
  170                                 error = copyout(cp, iov->iov_base, cnt);
  171                         else
  172                                 error = copyin(iov->iov_base, cp, cnt);
  173                         if (error)
  174                                 goto out;
  175                         break;
  176 
  177                 case UIO_SYSSPACE:
  178                         if (uio->uio_rw == UIO_READ)
  179                                 bcopy(cp, iov->iov_base, cnt);
  180                         else
  181                                 bcopy(iov->iov_base, cp, cnt);
  182                         break;
  183                 case UIO_NOCOPY:
  184                         break;
  185                 }
  186                 iov->iov_base = (char *)iov->iov_base + cnt;
  187                 iov->iov_len -= cnt;
  188                 uio->uio_resid -= cnt;
  189                 uio->uio_offset += cnt;
  190                 cp = (char *)cp + cnt;
  191                 n -= cnt;
  192         }
  193 out:
  194         if (td && save == 0) {
  195                 mtx_lock_spin(&sched_lock);
  196                 td->td_flags &= ~TDF_DEADLKTREAT;
  197                 mtx_unlock_spin(&sched_lock);
  198         }
  199         return (error);
  200 }
  201 
  202 /*
  203  * Wrapper for uiomove() that validates the arguments against a known-good
  204  * kernel buffer.  Currently, uiomove accepts a signed (n) argument, which
  205  * is almost definitely a bad thing, so we catch that here as well.  We
  206  * return a runtime failure, but it might be desirable to generate a runtime
  207  * assertion failure instead.
  208  */
  209 int
  210 uiomove_frombuf(void *buf, int buflen, struct uio *uio)
  211 {
  212         unsigned int offset, n;
  213 
  214         if (uio->uio_offset < 0 || uio->uio_resid < 0 ||
  215             (offset = uio->uio_offset) != uio->uio_offset)
  216                 return (EINVAL);
  217         if (buflen <= 0 || offset >= buflen)
  218                 return (0);
  219         if ((n = buflen - offset) > INT_MAX)
  220                 return (EINVAL);
  221         return (uiomove((char *)buf + offset, n, uio));
  222 }
  223 
  224 #ifdef ZERO_COPY_SOCKETS
  225 /*
  226  * Experimental support for zero-copy I/O
  227  */
  228 static int
  229 userspaceco(void *cp, u_int cnt, struct uio *uio, struct vm_object *obj,
  230     int disposable)
  231 {
  232         struct iovec *iov;
  233         int error;
  234 
  235         iov = uio->uio_iov;
  236         if (uio->uio_rw == UIO_READ) {
  237                 if ((so_zero_copy_receive != 0)
  238                  && (obj != NULL)
  239                  && ((cnt & PAGE_MASK) == 0)
  240                  && ((((intptr_t) iov->iov_base) & PAGE_MASK) == 0)
  241                  && ((uio->uio_offset & PAGE_MASK) == 0)
  242                  && ((((intptr_t) cp) & PAGE_MASK) == 0)
  243                  && (obj->type == OBJT_DEFAULT)
  244                  && (disposable != 0)) {
  245                         /* SOCKET: use page-trading */
  246                         /*
  247                          * We only want to call vm_pgmoveco() on
  248                          * disposeable pages, since it gives the
  249                          * kernel page to the userland process.
  250                          */
  251                         error = vm_pgmoveco(&curproc->p_vmspace->vm_map,
  252                                             obj, (vm_offset_t)cp,
  253                                             (vm_offset_t)iov->iov_base);
  254 
  255                         /*
  256                          * If we get an error back, attempt
  257                          * to use copyout() instead.  The
  258                          * disposable page should be freed
  259                          * automatically if we weren't able to move
  260                          * it into userland.
  261                          */
  262                         if (error != 0)
  263                                 error = copyout(cp, iov->iov_base, cnt);
  264                 } else {
  265                         error = copyout(cp, iov->iov_base, cnt);
  266                 }
  267         } else {
  268                 error = copyin(iov->iov_base, cp, cnt);
  269         }
  270         return (error);
  271 }
  272 
  273 int
  274 uiomoveco(void *cp, int n, struct uio *uio, struct vm_object *obj,
  275     int disposable)
  276 {
  277         struct iovec *iov;
  278         u_int cnt;
  279         int error;
  280 
  281         KASSERT(uio->uio_rw == UIO_READ || uio->uio_rw == UIO_WRITE,
  282             ("uiomoveco: mode"));
  283         KASSERT(uio->uio_segflg != UIO_USERSPACE || uio->uio_td == curthread,
  284             ("uiomoveco proc"));
  285 
  286         while (n > 0 && uio->uio_resid) {
  287                 iov = uio->uio_iov;
  288                 cnt = iov->iov_len;
  289                 if (cnt == 0) {
  290                         uio->uio_iov++;
  291                         uio->uio_iovcnt--;
  292                         continue;
  293                 }
  294                 if (cnt > n)
  295                         cnt = n;
  296 
  297                 switch (uio->uio_segflg) {
  298 
  299                 case UIO_USERSPACE:
  300                         if (ticks - PCPU_GET(switchticks) >= hogticks)
  301                                 uio_yield();
  302 
  303                         error = userspaceco(cp, cnt, uio, obj, disposable);
  304 
  305                         if (error)
  306                                 return (error);
  307                         break;
  308 
  309                 case UIO_SYSSPACE:
  310                         if (uio->uio_rw == UIO_READ)
  311                                 bcopy(cp, iov->iov_base, cnt);
  312                         else
  313                                 bcopy(iov->iov_base, cp, cnt);
  314                         break;
  315                 case UIO_NOCOPY:
  316                         break;
  317                 }
  318                 iov->iov_base = (char *)iov->iov_base + cnt;
  319                 iov->iov_len -= cnt;
  320                 uio->uio_resid -= cnt;
  321                 uio->uio_offset += cnt;
  322                 cp = (char *)cp + cnt;
  323                 n -= cnt;
  324         }
  325         return (0);
  326 }
  327 #endif /* ZERO_COPY_SOCKETS */
  328 
  329 /*
  330  * Give next character to user as result of read.
  331  */
  332 int
  333 ureadc(int c, struct uio *uio)
  334 {
  335         struct iovec *iov;
  336         char *iov_base;
  337 
  338 again:
  339         if (uio->uio_iovcnt == 0 || uio->uio_resid == 0)
  340                 panic("ureadc");
  341         iov = uio->uio_iov;
  342         if (iov->iov_len == 0) {
  343                 uio->uio_iovcnt--;
  344                 uio->uio_iov++;
  345                 goto again;
  346         }
  347         switch (uio->uio_segflg) {
  348 
  349         case UIO_USERSPACE:
  350                 if (subyte(iov->iov_base, c) < 0)
  351                         return (EFAULT);
  352                 break;
  353 
  354         case UIO_SYSSPACE:
  355                 iov_base = iov->iov_base;
  356                 *iov_base = c;
  357                 iov->iov_base = iov_base;
  358                 break;
  359 
  360         case UIO_NOCOPY:
  361                 break;
  362         }
  363         iov->iov_base = (char *)iov->iov_base + 1;
  364         iov->iov_len--;
  365         uio->uio_resid--;
  366         uio->uio_offset++;
  367         return (0);
  368 }
  369 
  370 /*
  371  * General routine to allocate a hash table.
  372  */
  373 void *
  374 hashinit(int elements, struct malloc_type *type, u_long *hashmask)
  375 {
  376         long hashsize;
  377         LIST_HEAD(generic, generic) *hashtbl;
  378         int i;
  379 
  380         if (elements <= 0)
  381                 panic("hashinit: bad elements");
  382         for (hashsize = 1; hashsize <= elements; hashsize <<= 1)
  383                 continue;
  384         hashsize >>= 1;
  385         hashtbl = malloc((u_long)hashsize * sizeof(*hashtbl), type, M_WAITOK);
  386         for (i = 0; i < hashsize; i++)
  387                 LIST_INIT(&hashtbl[i]);
  388         *hashmask = hashsize - 1;
  389         return (hashtbl);
  390 }
  391 
  392 void
  393 hashdestroy(void *vhashtbl, struct malloc_type *type, u_long hashmask)
  394 {
  395         LIST_HEAD(generic, generic) *hashtbl, *hp;
  396 
  397         hashtbl = vhashtbl;
  398         for (hp = hashtbl; hp <= &hashtbl[hashmask]; hp++)
  399                 if (!LIST_EMPTY(hp))
  400                         panic("hashdestroy: hash not empty");
  401         free(hashtbl, type);
  402 }
  403 
  404 static int primes[] = { 1, 13, 31, 61, 127, 251, 509, 761, 1021, 1531, 2039,
  405                         2557, 3067, 3583, 4093, 4603, 5119, 5623, 6143, 6653,
  406                         7159, 7673, 8191, 12281, 16381, 24571, 32749 };
  407 #define NPRIMES (sizeof(primes) / sizeof(primes[0]))
  408 
  409 /*
  410  * General routine to allocate a prime number sized hash table.
  411  */
  412 void *
  413 phashinit(int elements, struct malloc_type *type, u_long *nentries)
  414 {
  415         long hashsize;
  416         LIST_HEAD(generic, generic) *hashtbl;
  417         int i;
  418 
  419         if (elements <= 0)
  420                 panic("phashinit: bad elements");
  421         for (i = 1, hashsize = primes[1]; hashsize <= elements;) {
  422                 i++;
  423                 if (i == NPRIMES)
  424                         break;
  425                 hashsize = primes[i];
  426         }
  427         hashsize = primes[i - 1];
  428         hashtbl = malloc((u_long)hashsize * sizeof(*hashtbl), type, M_WAITOK);
  429         for (i = 0; i < hashsize; i++)
  430                 LIST_INIT(&hashtbl[i]);
  431         *nentries = hashsize;
  432         return (hashtbl);
  433 }
  434 
  435 void
  436 uio_yield(void)
  437 {
  438         struct thread *td;
  439 
  440         td = curthread;
  441         mtx_lock_spin(&sched_lock);
  442         DROP_GIANT();
  443         sched_prio(td, td->td_ksegrp->kg_user_pri); /* XXXKSE */
  444         td->td_proc->p_stats->p_ru.ru_nivcsw++;
  445         mi_switch();
  446         mtx_unlock_spin(&sched_lock);
  447         PICKUP_GIANT();
  448 }
  449 
  450 int
  451 copyinfrom(const void *src, void *dst, size_t len, int seg)
  452 {
  453         int error = 0;
  454 
  455         switch (seg) {
  456         case UIO_USERSPACE:
  457                 error = copyin(src, dst, len);
  458                 break;
  459         case UIO_SYSSPACE:
  460                 bcopy(src, dst, len);
  461                 break;
  462         default:
  463                 panic("copyinfrom: bad seg %d\n", seg);
  464         }
  465         return (error);
  466 }
  467 
  468 int
  469 copyinstrfrom(const void *src, void *dst, size_t len, size_t *copied, int seg)
  470 {
  471         int error = 0;
  472 
  473         switch (seg) {
  474         case UIO_USERSPACE:
  475                 error = copyinstr(src, dst, len, copied);
  476                 break;
  477         case UIO_SYSSPACE:
  478                 error = copystr(src, dst, len, copied);
  479                 break;
  480         default:
  481                 panic("copyinstrfrom: bad seg %d\n", seg);
  482         }
  483         return (error);
  484 }
Cache object: 9f297e7d4d52e20ef6397792a4543799
[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]
This page is part of the FreeBSD/Linux Linux Kernel Cross-Reference, and was automatically generated using a modified version of the LXR engine.
FreeBSD/Linux Kernel Cross Reference sys/kern/kern_subr.c

FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_subr.c
