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. 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.
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
34 * @(#)kern_subr.c 8.3 (Berkeley) 1/21/94
35 * $FreeBSD: src/sys/kern/kern_subr.c,v 1.31.2.2 2002/04/21 08:09:37 bde Exp $
38 #include <sys/param.h>
39 #include <sys/systm.h>
40 #include <sys/kernel.h>
42 #include <sys/malloc.h>
44 #include <sys/resourcevar.h>
45 #include <sys/sysctl.h>
47 #include <sys/vnode.h>
48 #include <sys/thread2.h>
49 #include <machine/limits.h>
51 #include <cpu/lwbuf.h>
54 #include <vm/vm_page.h>
55 #include <vm/vm_map.h>
57 SYSCTL_INT(_kern, KERN_IOV_MAX, iov_max, CTLFLAG_RD, NULL, UIO_MAXIOV,
58 "Maximum number of elements in an I/O vector; sysconf(_SC_IOV_MAX)");
61 copyin_nofault(const void *udaddr, void *kaddr, size_t len)
63 thread_t td = curthread;
66 atomic_set_int(&td->td_flags, TDF_NOFAULT);
67 error = copyin(udaddr, kaddr, len);
68 atomic_clear_int(&td->td_flags, TDF_NOFAULT);
73 copyout_nofault(const void *kaddr, void *udaddr, size_t len)
75 thread_t td = curthread;
78 atomic_set_int(&td->td_flags, TDF_NOFAULT);
79 error = copyout(kaddr, udaddr, len);
80 atomic_clear_int(&td->td_flags, TDF_NOFAULT);
85 * UIO_READ: copy the kernelspace cp to the user or kernelspace UIO
86 * UIO_WRITE: copy the user or kernelspace UIO to the kernelspace cp
88 * For userspace UIO's, uio_td must be the current thread.
90 * The syscall interface is responsible for limiting the length to
91 * ssize_t for things like read() or write() which return the bytes
92 * read or written as ssize_t. These functions work with unsigned
96 uiomove(caddr_t cp, size_t n, struct uio *uio)
98 thread_t td = curthread;
105 KASSERT(uio->uio_rw == UIO_READ || uio->uio_rw == UIO_WRITE,
107 KASSERT(uio->uio_segflg != UIO_USERSPACE || uio->uio_td == td,
111 save = td->td_flags & TDF_DEADLKTREAT;
112 td->td_flags |= TDF_DEADLKTREAT;
117 while (n > 0 && uio->uio_resid) {
129 switch (uio->uio_segflg) {
133 if (uio->uio_rw == UIO_READ)
134 error = copyout(cp, iov->iov_base, cnt);
136 error = copyin(iov->iov_base, cp, cnt);
139 if (uio->uio_rw == UIO_READ)
140 bcopy(cp, iov->iov_base, cnt);
142 bcopy(iov->iov_base, cp, cnt);
150 iov->iov_base = (char *)iov->iov_base + cnt;
152 uio->uio_resid -= cnt;
153 uio->uio_offset += cnt;
158 td->td_flags = (td->td_flags & ~TDF_DEADLKTREAT) | save;
165 * This is the same as uiomove() except (cp, n) is within the bounds of
166 * the passed, locked buffer. Under certain circumstances a VM fault
167 * occuring with a locked buffer held can result in a deadlock or an
168 * attempt to recursively lock the buffer.
170 * This procedure deals with these cases.
172 * If the buffer represents a regular file, is B_CACHE, but the last VM page
173 * is not fully valid we fix-up the last VM page. This should handle the
174 * recursive lock issue.
176 * Deadlocks are another issue. We are holding the vp and the bp locked
177 * and could deadlock against a different vp and/or bp if another thread is
178 * trying to access us while we accessing it. The only solution here is
179 * to release the bp and vnode lock and do the uio to/from a system buffer,
180 * then regain the locks and copyback (if applicable). XXX TODO.
183 uiomovebp(struct buf *bp, caddr_t cp, size_t n, struct uio *uio)
188 if (bp->b_vp && bp->b_vp->v_type == VREG &&
189 (bp->b_flags & B_CACHE) &&
190 (count = bp->b_xio.xio_npages) != 0 &&
191 (m = bp->b_xio.xio_pages[count-1])->valid != VM_PAGE_BITS_ALL) {
192 vm_page_zero_invalid(m, TRUE);
194 return (uiomove(cp, n, uio));
198 * uiomove() but fail for non-trivial VM faults, even if the VM fault is
199 * valid. Returns EFAULT if a VM fault occurred via the copyin/copyout
202 * This allows callers to hold e.g. a busy VM page, or a busy VM object,
203 * or a locked vnode through the call and then fall-back to safer code
207 uiomove_nofault(caddr_t cp, size_t n, struct uio *uio)
209 thread_t td = curthread;
212 atomic_set_int(&td->td_flags, TDF_NOFAULT);
213 error = uiomove(cp, n, uio);
214 atomic_clear_int(&td->td_flags, TDF_NOFAULT);
219 * Like uiomove() but copies zero-fill. Only allowed for UIO_READ,
220 * for obvious reasons.
223 uiomovez(size_t n, struct uio *uio)
229 KASSERT(uio->uio_rw == UIO_READ, ("uiomovez: mode"));
230 KASSERT(uio->uio_segflg != UIO_USERSPACE || uio->uio_td == curthread,
233 while (n > 0 && uio->uio_resid) {
244 switch (uio->uio_segflg) {
246 error = copyout(ZeroPage, iov->iov_base, cnt);
249 bzero(iov->iov_base, cnt);
257 iov->iov_base = (char *)iov->iov_base + cnt;
259 uio->uio_resid -= cnt;
260 uio->uio_offset += cnt;
267 * Wrapper for uiomove() that validates the arguments against a known-good
268 * kernel buffer. This function automatically indexes the buffer by
269 * uio_offset and handles all range checking.
272 uiomove_frombuf(void *buf, size_t buflen, struct uio *uio)
276 offset = (size_t)uio->uio_offset;
277 if ((off_t)offset != uio->uio_offset)
279 if (buflen == 0 || offset >= buflen)
281 return (uiomove((char *)buf + offset, buflen - offset, uio));
285 * Give next character to user as result of read.
288 ureadc(int c, struct uio *uio)
294 if (uio->uio_iovcnt == 0 || uio->uio_resid == 0)
297 if (iov->iov_len == 0) {
303 switch (uio->uio_segflg) {
305 if (subyte(iov->iov_base, c) < 0)
309 iov_base = iov->iov_base;
311 iov->iov_base = iov_base;
317 iov->iov_base = (char *)iov->iov_base + 1;
325 * General routine to allocate a hash table. Make the hash table size a
326 * power of 2 greater or equal to the number of elements requested, and
327 * store the masking value in *hashmask.
330 hashinit(int elements, struct malloc_type *type, u_long *hashmask)
333 LIST_HEAD(generic, generic) *hashtbl;
337 panic("hashinit: bad elements");
338 for (hashsize = 2; hashsize < elements; hashsize <<= 1)
340 hashtbl = kmalloc((u_long)hashsize * sizeof(*hashtbl), type, M_WAITOK);
341 for (i = 0; i < hashsize; i++)
342 LIST_INIT(&hashtbl[i]);
343 *hashmask = hashsize - 1;
348 hashdestroy(void *vhashtbl, struct malloc_type *type, u_long hashmask)
350 LIST_HEAD(generic, generic) *hashtbl, *hp;
353 for (hp = hashtbl; hp <= &hashtbl[hashmask]; hp++)
354 KASSERT(LIST_EMPTY(hp), ("%s: hash not empty", __func__));
355 kfree(hashtbl, type);
359 * This is a newer version which allocates a hash table of structures.
361 * The returned array will be zero'd. The caller is responsible for
362 * initializing the structures.
365 hashinit_ext(int elements, size_t size, struct malloc_type *type,
372 panic("hashinit: bad elements");
373 for (hashsize = 2; hashsize < elements; hashsize <<= 1)
375 hashtbl = kmalloc((size_t)hashsize * size, type, M_WAITOK | M_ZERO);
376 *hashmask = hashsize - 1;
380 static int primes[] = { 1, 13, 31, 61, 127, 251, 509, 761, 1021, 1531, 2039,
381 2557, 3067, 3583, 4093, 4603, 5119, 5623, 6143, 6653,
382 7159, 7673, 8191, 12281, 16381, 24571, 32749 };
383 #define NPRIMES NELEM(primes)
386 * General routine to allocate a prime number sized hash table.
389 phashinit(int elements, struct malloc_type *type, u_long *nentries)
392 LIST_HEAD(generic, generic) *hashtbl;
396 panic("phashinit: bad elements");
397 for (i = 1, hashsize = primes[1]; hashsize <= elements;) {
401 hashsize = primes[i];
403 hashsize = primes[i - 1];
404 hashtbl = kmalloc((u_long)hashsize * sizeof(*hashtbl), type, M_WAITOK);
405 for (i = 0; i < hashsize; i++)
406 LIST_INIT(&hashtbl[i]);
407 *nentries = hashsize;
412 * This is a newer version which allocates a hash table of structures
413 * in a prime-number size.
415 * The returned array will be zero'd. The caller is responsible for
416 * initializing the structures.
419 phashinit_ext(int elements, size_t size, struct malloc_type *type,
427 panic("phashinit: bad elements");
428 for (i = 1, hashsize = primes[1]; hashsize <= elements;) {
432 hashsize = primes[i];
434 hashsize = primes[i - 1];
435 hashtbl = kmalloc((size_t)hashsize * size, type, M_WAITOK | M_ZERO);
436 *nentries = hashsize;
441 * Copyin an iovec. If the iovec array fits, use the preallocated small
442 * iovec structure. If it is too big, dynamically allocate an iovec array
443 * of sufficient size.
448 iovec_copyin(struct iovec *uiov, struct iovec **kiov, struct iovec *siov,
449 size_t iov_cnt, size_t *iov_len)
455 if (iov_cnt > UIO_MAXIOV)
457 if (iov_cnt > UIO_SMALLIOV) {
458 *kiov = kmalloc(sizeof(struct iovec) * iov_cnt, M_IOV,
463 error = copyin(uiov, *kiov, iov_cnt * sizeof(struct iovec));
466 for (i = 0, iovp = *kiov; i < iov_cnt; i++, iovp++) {
468 * Check for both *iov_len overflows and out of
469 * range iovp->iov_len's. We limit to the
470 * capabilities of signed integers.
472 * GCC4 - overflow check opt requires assign/test.
474 len = *iov_len + iovp->iov_len;
482 * From userland disallow iovec's which exceed the sized size
483 * limit as the system calls return ssize_t.
485 * NOTE: Internal kernel interfaces can handle the unsigned
488 if (error == 0 && (ssize_t)*iov_len < 0)
492 iovec_free(kiov, siov);
498 * Copyright (c) 2004 Alan L. Cox <alc@cs.rice.edu>
499 * Copyright (c) 1982, 1986, 1991, 1993
500 * The Regents of the University of California. All rights reserved.
501 * (c) UNIX System Laboratories, Inc.
502 * All or some portions of this file are derived from material licensed
503 * to the University of California by American Telephone and Telegraph
504 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
505 * the permission of UNIX System Laboratories, Inc.
507 * Redistribution and use in source and binary forms, with or without
508 * modification, are permitted provided that the following conditions
510 * 1. Redistributions of source code must retain the above copyright
511 * notice, this list of conditions and the following disclaimer.
512 * 2. Redistributions in binary form must reproduce the above copyright
513 * notice, this list of conditions and the following disclaimer in the
514 * documentation and/or other materials provided with the distribution.
515 * 4. Neither the name of the University nor the names of its contributors
516 * may be used to endorse or promote products derived from this software
517 * without specific prior written permission.
519 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
520 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
521 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
522 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
523 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
524 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
525 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
526 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
527 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
528 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
531 * @(#)kern_subr.c 8.3 (Berkeley) 1/21/94
532 * $FreeBSD: src/sys/i386/i386/uio_machdep.c,v 1.1 2004/03/21 20:28:36 alc Exp $
536 * Implement uiomove(9) from physical memory using lwbuf's to reduce
537 * the creation and destruction of ephemeral mappings.
540 uiomove_fromphys(vm_page_t *ma, vm_offset_t offset, size_t n, struct uio *uio)
542 struct lwbuf lwb_cache;
544 struct thread *td = curthread;
547 vm_offset_t page_offset;
553 KASSERT(uio->uio_rw == UIO_READ || uio->uio_rw == UIO_WRITE,
554 ("uiomove_fromphys: mode"));
555 KASSERT(uio->uio_segflg != UIO_USERSPACE || uio->uio_td == curthread,
556 ("uiomove_fromphys proc"));
559 save = td->td_flags & TDF_DEADLKTREAT;
560 td->td_flags |= TDF_DEADLKTREAT;
563 while (n > 0 && uio->uio_resid) {
573 page_offset = offset & PAGE_MASK;
574 cnt = min(cnt, PAGE_SIZE - page_offset);
575 m = ma[offset >> PAGE_SHIFT];
576 lwb = lwbuf_alloc(m, &lwb_cache);
577 cp = (char *)lwbuf_kva(lwb) + page_offset;
579 switch (uio->uio_segflg) {
582 * note: removed uioyield (it was the wrong place to
585 if (uio->uio_rw == UIO_READ)
586 error = copyout(cp, iov->iov_base, cnt);
588 error = copyin(iov->iov_base, cp, cnt);
595 if (uio->uio_rw == UIO_READ)
596 bcopy(cp, iov->iov_base, cnt);
598 bcopy(iov->iov_base, cp, cnt);
604 iov->iov_base = (char *)iov->iov_base + cnt;
606 uio->uio_resid -= cnt;
607 uio->uio_offset += cnt;
614 td->td_flags &= ~TDF_DEADLKTREAT;