FreeBSD-5.3/sys/kern/kern_subr.c
/*
* Copyright (c) 1982, 1986, 1991, 1993
* The Regents of the University of California. All rights reserved.
* (c) UNIX System Laboratories, Inc.
* All or some portions of this file are derived from material licensed
* to the University of California by American Telephone and Telegraph
* Co. or Unix System Laboratories, Inc. and are reproduced herein with
* the permission of UNIX System Laboratories, Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)kern_subr.c 8.3 (Berkeley) 1/21/94
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD: src/sys/kern/kern_subr.c,v 1.88 2004/07/10 15:42:16 phk Exp $");
#include "opt_zero.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/ktr.h>
#include <sys/limits.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/malloc.h>
#include <sys/resourcevar.h>
#include <sys/sched.h>
#include <sys/sysctl.h>
#include <sys/vnode.h>
#include <vm/vm.h>
#include <vm/vm_page.h>
#include <vm/vm_map.h>
#ifdef ZERO_COPY_SOCKETS
#include <vm/vm_param.h>
#include <vm/vm_object.h>
#endif
SYSCTL_INT(_kern, KERN_IOV_MAX, iov_max, CTLFLAG_RD, NULL, UIO_MAXIOV,
"Maximum number of elements in an I/O vector; sysconf(_SC_IOV_MAX)");
#ifdef ZERO_COPY_SOCKETS
/* Declared in uipc_socket.c */
extern int so_zero_copy_receive;
static int
vm_pgmoveco(vm_map_t mapa, vm_object_t srcobj, vm_offset_t kaddr,
vm_offset_t uaddr)
{
vm_map_t map = mapa;
vm_page_t kern_pg, user_pg;
vm_object_t uobject;
vm_map_entry_t entry;
vm_pindex_t upindex, kpindex;
vm_prot_t prot;
boolean_t wired;
/*
* First lookup the kernel page.
*/
kern_pg = PHYS_TO_VM_PAGE(vtophys(kaddr));
/*
* XXX The vm object containing kern_pg needs locking.
*/
if ((vm_map_lookup(&map, uaddr,
VM_PROT_WRITE, &entry, &uobject,
&upindex, &prot, &wired)) != KERN_SUCCESS) {
return(EFAULT);
}
VM_OBJECT_LOCK(uobject);
if ((user_pg = vm_page_lookup(uobject, upindex)) != NULL) {
do
vm_page_lock_queues();
while (vm_page_sleep_if_busy(user_pg, 1, "vm_pgmoveco"));
vm_page_busy(user_pg);
pmap_remove_all(user_pg);
vm_page_free(user_pg);
} else
vm_page_lock_queues();
if (kern_pg->busy || ((kern_pg->queue - kern_pg->pc) == PQ_FREE) ||
(kern_pg->hold_count != 0)|| (kern_pg->flags & PG_BUSY)) {
printf("vm_pgmoveco: pindex(%lu), busy(%d), PG_BUSY(%d), "
"hold(%d) paddr(0x%lx)\n", (u_long)kern_pg->pindex,
kern_pg->busy, (kern_pg->flags & PG_BUSY) ? 1 : 0,
kern_pg->hold_count, (u_long)kern_pg->phys_addr);
if ((kern_pg->queue - kern_pg->pc) == PQ_FREE)
panic("vm_pgmoveco: renaming free page");
else
panic("vm_pgmoveco: renaming busy page");
}
kpindex = kern_pg->pindex;
vm_page_busy(kern_pg);
vm_page_rename(kern_pg, uobject, upindex);
vm_page_flag_clear(kern_pg, PG_BUSY);
kern_pg->valid = VM_PAGE_BITS_ALL;
vm_page_unlock_queues();
VM_OBJECT_UNLOCK(uobject);
vm_map_lookup_done(map, entry);
return(KERN_SUCCESS);
}
#endif /* ZERO_COPY_SOCKETS */
int
uiomove(void *cp, int n, struct uio *uio)
{
struct thread *td = curthread;
struct iovec *iov;
u_int cnt;
int error = 0;
int save = 0;
KASSERT(uio->uio_rw == UIO_READ || uio->uio_rw == UIO_WRITE,
("uiomove: mode"));
KASSERT(uio->uio_segflg != UIO_USERSPACE || uio->uio_td == curthread,
("uiomove proc"));
save = td->td_pflags & TDP_DEADLKTREAT;
td->td_pflags |= TDP_DEADLKTREAT;
while (n > 0 && uio->uio_resid) {
iov = uio->uio_iov;
cnt = iov->iov_len;
if (cnt == 0) {
uio->uio_iov++;
uio->uio_iovcnt--;
continue;
}
if (cnt > n)
cnt = n;
switch (uio->uio_segflg) {
case UIO_USERSPACE:
if (ticks - PCPU_GET(switchticks) >= hogticks)
uio_yield();
if (uio->uio_rw == UIO_READ)
error = copyout(cp, iov->iov_base, cnt);
else
error = copyin(iov->iov_base, cp, cnt);
if (error)
goto out;
break;
case UIO_SYSSPACE:
if (uio->uio_rw == UIO_READ)
bcopy(cp, iov->iov_base, cnt);
else
bcopy(iov->iov_base, cp, cnt);
break;
case UIO_NOCOPY:
break;
}
iov->iov_base = (char *)iov->iov_base + cnt;
iov->iov_len -= cnt;
uio->uio_resid -= cnt;
uio->uio_offset += cnt;
cp = (char *)cp + cnt;
n -= cnt;
}
out:
if (save == 0)
td->td_pflags &= ~TDP_DEADLKTREAT;
return (error);
}
/*
* Wrapper for uiomove() that validates the arguments against a known-good
* kernel buffer. Currently, uiomove accepts a signed (n) argument, which
* is almost definitely a bad thing, so we catch that here as well. We
* return a runtime failure, but it might be desirable to generate a runtime
* assertion failure instead.
*/
int
uiomove_frombuf(void *buf, int buflen, struct uio *uio)
{
unsigned int offset, n;
if (uio->uio_offset < 0 || uio->uio_resid < 0 ||
(offset = uio->uio_offset) != uio->uio_offset)
return (EINVAL);
if (buflen <= 0 || offset >= buflen)
return (0);
if ((n = buflen - offset) > INT_MAX)
return (EINVAL);
return (uiomove((char *)buf + offset, n, uio));
}
#ifdef ZERO_COPY_SOCKETS
/*
* Experimental support for zero-copy I/O
*/
static int
userspaceco(void *cp, u_int cnt, struct uio *uio, struct vm_object *obj,
int disposable)
{
struct iovec *iov;
int error;
iov = uio->uio_iov;
if (uio->uio_rw == UIO_READ) {
if ((so_zero_copy_receive != 0)
&& (obj != NULL)
&& ((cnt & PAGE_MASK) == 0)
&& ((((intptr_t) iov->iov_base) & PAGE_MASK) == 0)
&& ((uio->uio_offset & PAGE_MASK) == 0)
&& ((((intptr_t) cp) & PAGE_MASK) == 0)
&& (obj->type == OBJT_DEFAULT)
&& (disposable != 0)) {
/* SOCKET: use page-trading */
/*
* We only want to call vm_pgmoveco() on
* disposeable pages, since it gives the
* kernel page to the userland process.
*/
error = vm_pgmoveco(&curproc->p_vmspace->vm_map,
obj, (vm_offset_t)cp,
(vm_offset_t)iov->iov_base);
/*
* If we get an error back, attempt
* to use copyout() instead. The
* disposable page should be freed
* automatically if we weren't able to move
* it into userland.
*/
if (error != 0)
error = copyout(cp, iov->iov_base, cnt);
} else {
error = copyout(cp, iov->iov_base, cnt);
}
} else {
error = copyin(iov->iov_base, cp, cnt);
}
return (error);
}
int
uiomoveco(void *cp, int n, struct uio *uio, struct vm_object *obj,
int disposable)
{
struct iovec *iov;
u_int cnt;
int error;
KASSERT(uio->uio_rw == UIO_READ || uio->uio_rw == UIO_WRITE,
("uiomoveco: mode"));
KASSERT(uio->uio_segflg != UIO_USERSPACE || uio->uio_td == curthread,
("uiomoveco proc"));
while (n > 0 && uio->uio_resid) {
iov = uio->uio_iov;
cnt = iov->iov_len;
if (cnt == 0) {
uio->uio_iov++;
uio->uio_iovcnt--;
continue;
}
if (cnt > n)
cnt = n;
switch (uio->uio_segflg) {
case UIO_USERSPACE:
if (ticks - PCPU_GET(switchticks) >= hogticks)
uio_yield();
error = userspaceco(cp, cnt, uio, obj, disposable);
if (error)
return (error);
break;
case UIO_SYSSPACE:
if (uio->uio_rw == UIO_READ)
bcopy(cp, iov->iov_base, cnt);
else
bcopy(iov->iov_base, cp, cnt);
break;
case UIO_NOCOPY:
break;
}
iov->iov_base = (char *)iov->iov_base + cnt;
iov->iov_len -= cnt;
uio->uio_resid -= cnt;
uio->uio_offset += cnt;
cp = (char *)cp + cnt;
n -= cnt;
}
return (0);
}
#endif /* ZERO_COPY_SOCKETS */
/*
* Give next character to user as result of read.
*/
int
ureadc(int c, struct uio *uio)
{
struct iovec *iov;
char *iov_base;
again:
if (uio->uio_iovcnt == 0 || uio->uio_resid == 0)
panic("ureadc");
iov = uio->uio_iov;
if (iov->iov_len == 0) {
uio->uio_iovcnt--;
uio->uio_iov++;
goto again;
}
switch (uio->uio_segflg) {
case UIO_USERSPACE:
if (subyte(iov->iov_base, c) < 0)
return (EFAULT);
break;
case UIO_SYSSPACE:
iov_base = iov->iov_base;
*iov_base = c;
iov->iov_base = iov_base;
break;
case UIO_NOCOPY:
break;
}
iov->iov_base = (char *)iov->iov_base + 1;
iov->iov_len--;
uio->uio_resid--;
uio->uio_offset++;
return (0);
}
/*
* General routine to allocate a hash table.
*/
void *
hashinit(int elements, struct malloc_type *type, u_long *hashmask)
{
long hashsize;
LIST_HEAD(generic, generic) *hashtbl;
int i;
if (elements <= 0)
panic("hashinit: bad elements");
for (hashsize = 1; hashsize <= elements; hashsize <<= 1)
continue;
hashsize >>= 1;
hashtbl = malloc((u_long)hashsize * sizeof(*hashtbl), type, M_WAITOK);
for (i = 0; i < hashsize; i++)
LIST_INIT(&hashtbl[i]);
*hashmask = hashsize - 1;
return (hashtbl);
}
void
hashdestroy(void *vhashtbl, struct malloc_type *type, u_long hashmask)
{
LIST_HEAD(generic, generic) *hashtbl, *hp;
hashtbl = vhashtbl;
for (hp = hashtbl; hp <= &hashtbl[hashmask]; hp++)
if (!LIST_EMPTY(hp))
panic("hashdestroy: hash not empty");
free(hashtbl, type);
}
static int primes[] = { 1, 13, 31, 61, 127, 251, 509, 761, 1021, 1531, 2039,
2557, 3067, 3583, 4093, 4603, 5119, 5623, 6143, 6653,
7159, 7673, 8191, 12281, 16381, 24571, 32749 };
#define NPRIMES (sizeof(primes) / sizeof(primes[0]))
/*
* General routine to allocate a prime number sized hash table.
*/
void *
phashinit(int elements, struct malloc_type *type, u_long *nentries)
{
long hashsize;
LIST_HEAD(generic, generic) *hashtbl;
int i;
if (elements <= 0)
panic("phashinit: bad elements");
for (i = 1, hashsize = primes[1]; hashsize <= elements;) {
i++;
if (i == NPRIMES)
break;
hashsize = primes[i];
}
hashsize = primes[i - 1];
hashtbl = malloc((u_long)hashsize * sizeof(*hashtbl), type, M_WAITOK);
for (i = 0; i < hashsize; i++)
LIST_INIT(&hashtbl[i]);
*nentries = hashsize;
return (hashtbl);
}
void
uio_yield(void)
{
struct thread *td;
td = curthread;
mtx_lock_spin(&sched_lock);
DROP_GIANT();
sched_prio(td, td->td_ksegrp->kg_user_pri); /* XXXKSE */
mi_switch(SW_INVOL, NULL);
mtx_unlock_spin(&sched_lock);
PICKUP_GIANT();
}
int
copyinfrom(const void * __restrict src, void * __restrict dst, size_t len,
int seg)
{
int error = 0;
switch (seg) {
case UIO_USERSPACE:
error = copyin(src, dst, len);
break;
case UIO_SYSSPACE:
bcopy(src, dst, len);
break;
default:
panic("copyinfrom: bad seg %d\n", seg);
}
return (error);
}
int
copyinstrfrom(const void * __restrict src, void * __restrict dst, size_t len,
size_t * __restrict copied, int seg)
{
int error = 0;
switch (seg) {
case UIO_USERSPACE:
error = copyinstr(src, dst, len, copied);
break;
case UIO_SYSSPACE:
error = copystr(src, dst, len, copied);
break;
default:
panic("copyinstrfrom: bad seg %d\n", seg);
}
return (error);
}
int
copyiniov(struct iovec *iovp, u_int iovcnt, struct iovec **iov, int error)
{
u_int iovlen;
*iov = NULL;
if (iovcnt > UIO_MAXIOV)
return (error);
iovlen = iovcnt * sizeof (struct iovec);
*iov = malloc(iovlen, M_IOV, M_WAITOK);
error = copyin(iovp, *iov, iovlen);
if (error) {
free(*iov, M_IOV);
*iov = NULL;
}
return (error);
}
int
copyinuio(struct iovec *iovp, u_int iovcnt, struct uio **uiop)
{
struct iovec *iov;
struct uio *uio;
u_int iovlen;
int error, i;
*uiop = NULL;
if (iovcnt > UIO_MAXIOV)
return (EINVAL);
iovlen = iovcnt * sizeof (struct iovec);
uio = malloc(iovlen + sizeof *uio, M_IOV, M_WAITOK);
iov = (struct iovec *)(uio + 1);
error = copyin(iovp, iov, iovlen);
if (error) {
free(uio, M_IOV);
return (error);
}
uio->uio_iov = iov;
uio->uio_iovcnt = iovcnt;
uio->uio_segflg = UIO_USERSPACE;
uio->uio_offset = -1;
uio->uio_resid = 0;
for (i = 0; i < iovcnt; i++) {
if (iov->iov_len > INT_MAX - uio->uio_resid) {
free(uio, M_IOV);
return (EINVAL);
}
uio->uio_resid += iov->iov_len;
iov++;
}
*uiop = uio;
return (0);
}
struct uio *
cloneuio(struct uio *uiop)
{
struct uio *uio;
int iovlen;
iovlen = uiop->uio_iovcnt * sizeof (struct iovec);
uio = malloc(iovlen + sizeof *uio, M_IOV, M_WAITOK);
*uio = *uiop;
uio->uio_iov = (struct iovec *)(uio + 1);
bcopy(uiop->uio_iov, uio->uio_iov, iovlen);
return (uio);
}