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.
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
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.
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
38 * @(#)kern_subr.c 8.3 (Berkeley) 1/21/94
39 * $FreeBSD: src/sys/kern/kern_subr.c,v 1.31.2.2 2002/04/21 08:09:37 bde Exp $
42 #include <sys/param.h>
43 #include <sys/systm.h>
44 #include <sys/kernel.h>
46 #include <sys/malloc.h>
48 #include <sys/resourcevar.h>
49 #include <sys/sysctl.h>
51 #include <sys/vnode.h>
52 #include <sys/thread2.h>
53 #include <machine/limits.h>
55 #include <cpu/lwbuf.h>
58 #include <vm/vm_page.h>
59 #include <vm/vm_map.h>
61 SYSCTL_INT(_kern, KERN_IOV_MAX, iov_max, CTLFLAG_RD, NULL, UIO_MAXIOV,
62 "Maximum number of elements in an I/O vector; sysconf(_SC_IOV_MAX)");
65 * UIO_READ: copy the kernelspace cp to the user or kernelspace UIO
66 * UIO_WRITE: copy the user or kernelspace UIO to the kernelspace cp
68 * For userspace UIO's, uio_td must be the current thread.
70 * The syscall interface is responsible for limiting the length to
71 * ssize_t for things like read() or write() which return the bytes
72 * read or written as ssize_t. These functions work with unsigned
76 uiomove(caddr_t cp, size_t n, struct uio *uio)
78 thread_t td = curthread;
84 KASSERT(uio->uio_rw == UIO_READ || uio->uio_rw == UIO_WRITE,
86 KASSERT(uio->uio_segflg != UIO_USERSPACE || uio->uio_td == td,
90 save = td->td_flags & TDF_DEADLKTREAT;
91 td->td_flags |= TDF_DEADLKTREAT;
94 while (n > 0 && uio->uio_resid) {
105 switch (uio->uio_segflg) {
109 if (uio->uio_rw == UIO_READ)
110 error = copyout(cp, iov->iov_base, cnt);
112 error = copyin(iov->iov_base, cp, cnt);
118 if (uio->uio_rw == UIO_READ)
119 bcopy(cp, iov->iov_base, cnt);
121 bcopy(iov->iov_base, cp, cnt);
126 iov->iov_base = (char *)iov->iov_base + cnt;
128 uio->uio_resid -= cnt;
129 uio->uio_offset += cnt;
134 td->td_flags = (td->td_flags & ~TDF_DEADLKTREAT) | save;
140 * This is the same as uiomove() except (cp, n) is within the bounds of
141 * the passed, locked buffer. Under certain circumstances a VM fault
142 * occuring with a locked buffer held can result in a deadlock or an
143 * attempt to recursively lock the buffer.
145 * This procedure deals with these cases.
147 * If the buffer represents a regular file, is B_CACHE, but the last VM page
148 * is not fully valid we fix-up the last VM page. This should handle the
149 * recursive lock issue.
151 * Deadlocks are another issue. We are holding the vp and the bp locked
152 * and could deadlock against a different vp and/or bp if another thread is
153 * trying to access us while we accessing it. The only solution here is
154 * to release the bp and vnode lock and do the uio to/from a system buffer,
155 * then regain the locks and copyback (if applicable). XXX TODO.
158 uiomovebp(struct buf *bp, caddr_t cp, size_t n, struct uio *uio)
163 if (bp->b_vp && bp->b_vp->v_type == VREG &&
164 (bp->b_flags & B_CACHE) &&
165 (count = bp->b_xio.xio_npages) != 0 &&
166 (m = bp->b_xio.xio_pages[count-1])->valid != VM_PAGE_BITS_ALL) {
167 vm_page_zero_invalid(m, TRUE);
169 return (uiomove(cp, n, uio));
173 * Like uiomove() but copies zero-fill. Only allowed for UIO_READ,
174 * for obvious reasons.
177 uiomovez(size_t n, struct uio *uio)
183 KASSERT(uio->uio_rw == UIO_READ, ("uiomovez: mode"));
184 KASSERT(uio->uio_segflg != UIO_USERSPACE || uio->uio_td == curthread,
187 while (n > 0 && uio->uio_resid) {
198 switch (uio->uio_segflg) {
200 error = copyout(ZeroPage, iov->iov_base, cnt);
205 bzero(iov->iov_base, cnt);
210 iov->iov_base = (char *)iov->iov_base + cnt;
212 uio->uio_resid -= cnt;
213 uio->uio_offset += cnt;
220 * Wrapper for uiomove() that validates the arguments against a known-good
221 * kernel buffer. This function automatically indexes the buffer by
222 * uio_offset and handles all range checking.
225 uiomove_frombuf(void *buf, size_t buflen, struct uio *uio)
229 offset = (size_t)uio->uio_offset;
230 if ((off_t)offset != uio->uio_offset)
232 if (buflen == 0 || offset >= buflen)
234 return (uiomove((char *)buf + offset, buflen - offset, uio));
238 * Give next character to user as result of read.
241 ureadc(int c, struct uio *uio)
247 if (uio->uio_iovcnt == 0 || uio->uio_resid == 0)
250 if (iov->iov_len == 0) {
255 switch (uio->uio_segflg) {
258 if (subyte(iov->iov_base, c) < 0)
263 iov_base = iov->iov_base;
265 iov->iov_base = iov_base;
271 iov->iov_base = (char *)iov->iov_base + 1;
279 * General routine to allocate a hash table. Make the hash table size a
280 * power of 2 greater or equal to the number of elements requested, and
281 * store the masking value in *hashmask.
284 hashinit(int elements, struct malloc_type *type, u_long *hashmask)
287 LIST_HEAD(generic, generic) *hashtbl;
291 panic("hashinit: bad elements");
292 for (hashsize = 2; hashsize < elements; hashsize <<= 1)
294 hashtbl = kmalloc((u_long)hashsize * sizeof(*hashtbl), type, M_WAITOK);
295 for (i = 0; i < hashsize; i++)
296 LIST_INIT(&hashtbl[i]);
297 *hashmask = hashsize - 1;
302 hashdestroy(void *vhashtbl, struct malloc_type *type, u_long hashmask)
304 LIST_HEAD(generic, generic) *hashtbl, *hp;
307 for (hp = hashtbl; hp <= &hashtbl[hashmask]; hp++)
308 KASSERT(LIST_EMPTY(hp), ("%s: hash not empty", __func__));
309 kfree(hashtbl, type);
313 * This is a newer version which allocates a hash table of structures.
315 * The returned array will be zero'd. The caller is responsible for
316 * initializing the structures.
319 hashinit_ext(int elements, size_t size, struct malloc_type *type,
326 panic("hashinit: bad elements");
327 for (hashsize = 2; hashsize < elements; hashsize <<= 1)
329 hashtbl = kmalloc((size_t)hashsize * size, type, M_WAITOK | M_ZERO);
330 *hashmask = hashsize - 1;
334 static int primes[] = { 1, 13, 31, 61, 127, 251, 509, 761, 1021, 1531, 2039,
335 2557, 3067, 3583, 4093, 4603, 5119, 5623, 6143, 6653,
336 7159, 7673, 8191, 12281, 16381, 24571, 32749 };
337 #define NPRIMES NELEM(primes)
340 * General routine to allocate a prime number sized hash table.
343 phashinit(int elements, struct malloc_type *type, u_long *nentries)
346 LIST_HEAD(generic, generic) *hashtbl;
350 panic("phashinit: bad elements");
351 for (i = 1, hashsize = primes[1]; hashsize <= elements;) {
355 hashsize = primes[i];
357 hashsize = primes[i - 1];
358 hashtbl = kmalloc((u_long)hashsize * sizeof(*hashtbl), type, M_WAITOK);
359 for (i = 0; i < hashsize; i++)
360 LIST_INIT(&hashtbl[i]);
361 *nentries = hashsize;
366 * This is a newer version which allocates a hash table of structures
367 * in a prime-number size.
369 * The returned array will be zero'd. The caller is responsible for
370 * initializing the structures.
373 phashinit_ext(int elements, size_t size, struct malloc_type *type,
381 panic("phashinit: bad elements");
382 for (i = 1, hashsize = primes[1]; hashsize <= elements;) {
386 hashsize = primes[i];
388 hashsize = primes[i - 1];
389 hashtbl = kmalloc((size_t)hashsize * size, type, M_WAITOK | M_ZERO);
390 *nentries = hashsize;
395 * Copyin an iovec. If the iovec array fits, use the preallocated small
396 * iovec structure. If it is too big, dynamically allocate an iovec array
397 * of sufficient size.
402 iovec_copyin(struct iovec *uiov, struct iovec **kiov, struct iovec *siov,
403 size_t iov_cnt, size_t *iov_len)
409 if (iov_cnt > UIO_MAXIOV)
411 if (iov_cnt > UIO_SMALLIOV) {
412 *kiov = kmalloc(sizeof(struct iovec) * iov_cnt, M_IOV,
417 error = copyin(uiov, *kiov, iov_cnt * sizeof(struct iovec));
420 for (i = 0, iovp = *kiov; i < iov_cnt; i++, iovp++) {
422 * Check for both *iov_len overflows and out of
423 * range iovp->iov_len's. We limit to the
424 * capabilities of signed integers.
426 * GCC4 - overflow check opt requires assign/test.
428 len = *iov_len + iovp->iov_len;
436 * From userland disallow iovec's which exceed the sized size
437 * limit as the system calls return ssize_t.
439 * NOTE: Internal kernel interfaces can handle the unsigned
442 if (error == 0 && (ssize_t)*iov_len < 0)
446 iovec_free(kiov, siov);
452 * Copyright (c) 2004 Alan L. Cox <alc@cs.rice.edu>
453 * Copyright (c) 1982, 1986, 1991, 1993
454 * The Regents of the University of California. All rights reserved.
455 * (c) UNIX System Laboratories, Inc.
456 * All or some portions of this file are derived from material licensed
457 * to the University of California by American Telephone and Telegraph
458 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
459 * the permission of UNIX System Laboratories, Inc.
461 * Redistribution and use in source and binary forms, with or without
462 * modification, are permitted provided that the following conditions
464 * 1. Redistributions of source code must retain the above copyright
465 * notice, this list of conditions and the following disclaimer.
466 * 2. Redistributions in binary form must reproduce the above copyright
467 * notice, this list of conditions and the following disclaimer in the
468 * documentation and/or other materials provided with the distribution.
469 * 4. Neither the name of the University nor the names of its contributors
470 * may be used to endorse or promote products derived from this software
471 * without specific prior written permission.
473 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
474 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
475 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
476 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
477 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
478 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
479 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
480 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
481 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
482 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
485 * @(#)kern_subr.c 8.3 (Berkeley) 1/21/94
486 * $FreeBSD: src/sys/i386/i386/uio_machdep.c,v 1.1 2004/03/21 20:28:36 alc Exp $
490 * Implement uiomove(9) from physical memory using lwbuf's to reduce
491 * the creation and destruction of ephemeral mappings.
494 uiomove_fromphys(vm_page_t *ma, vm_offset_t offset, size_t n, struct uio *uio)
496 struct lwbuf lwb_cache;
498 struct thread *td = curthread;
501 vm_offset_t page_offset;
507 KASSERT(uio->uio_rw == UIO_READ || uio->uio_rw == UIO_WRITE,
508 ("uiomove_fromphys: mode"));
509 KASSERT(uio->uio_segflg != UIO_USERSPACE || uio->uio_td == curthread,
510 ("uiomove_fromphys proc"));
513 save = td->td_flags & TDF_DEADLKTREAT;
514 td->td_flags |= TDF_DEADLKTREAT;
517 while (n > 0 && uio->uio_resid) {
527 page_offset = offset & PAGE_MASK;
528 cnt = min(cnt, PAGE_SIZE - page_offset);
529 m = ma[offset >> PAGE_SHIFT];
530 lwb = lwbuf_alloc(m, &lwb_cache);
531 cp = (char *)lwbuf_kva(lwb) + page_offset;
532 switch (uio->uio_segflg) {
535 * note: removed uioyield (it was the wrong place to
538 if (uio->uio_rw == UIO_READ)
539 error = copyout(cp, iov->iov_base, cnt);
541 error = copyin(iov->iov_base, cp, cnt);
548 if (uio->uio_rw == UIO_READ)
549 bcopy(cp, iov->iov_base, cnt);
551 bcopy(iov->iov_base, cp, cnt);
557 iov->iov_base = (char *)iov->iov_base + cnt;
559 uio->uio_resid -= cnt;
560 uio->uio_offset += cnt;
567 td->td_flags &= ~TDF_DEADLKTREAT;