1/*-
2 * Copyright (c) 2004 Alan L. Cox <alc@cs.rice.edu>
3 * Copyright (c) 1982, 1986, 1991, 1993
4 *	The Regents of the University of California.  All rights reserved.
5 * (c) UNIX System Laboratories, Inc.
6 * All or some portions of this file are derived from material licensed
7 * to the University of California by American Telephone and Telegraph
8 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
9 * the permission of UNIX System Laboratories, Inc.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 *    notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 *    notice, this list of conditions and the following disclaimer in the
18 *    documentation and/or other materials provided with the distribution.
19 * 3. Neither the name of the University nor the names of its contributors
20 *    may be used to endorse or promote products derived from this software
21 *    without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 *
35 *	@(#)kern_subr.c	8.3 (Berkeley) 1/21/94
36 */
37
38#include <sys/cdefs.h>
39__FBSDID("$FreeBSD$");
40
41#include <sys/param.h>
42#include <sys/systm.h>
43#include <sys/kernel.h>
44#include <sys/lock.h>
45#include <sys/mutex.h>
46#include <sys/proc.h>
47#include <sys/sched.h>
48#include <sys/sf_buf.h>
49#include <sys/uio.h>
50
51#include <vm/vm.h>
52#include <vm/vm_page.h>
53
54/*
55 * Implement uiomove(9) from physical memory using sf_bufs to reduce
56 * the creation and destruction of ephemeral mappings.
57 */
58int
59uiomove_fromphys(vm_page_t ma[], vm_offset_t offset, int n, struct uio *uio)
60{
61	struct sf_buf *sf;
62	struct thread *td = curthread;
63	struct iovec *iov;
64	void *cp;
65	vm_offset_t page_offset;
66	size_t cnt;
67	int error = 0;
68	int save = 0;
69
70	KASSERT(uio->uio_rw == UIO_READ || uio->uio_rw == UIO_WRITE,
71	    ("uiomove_fromphys: mode"));
72	KASSERT(uio->uio_segflg != UIO_USERSPACE || uio->uio_td == curthread,
73	    ("uiomove_fromphys proc"));
74	save = td->td_pflags & TDP_DEADLKTREAT;
75	td->td_pflags |= TDP_DEADLKTREAT;
76	while (n > 0 && uio->uio_resid) {
77		iov = uio->uio_iov;
78		cnt = iov->iov_len;
79		if (cnt == 0) {
80			uio->uio_iov++;
81			uio->uio_iovcnt--;
82			continue;
83		}
84		if (cnt > n)
85			cnt = n;
86		page_offset = offset & PAGE_MASK;
87		cnt = min(cnt, PAGE_SIZE - page_offset);
88		sched_pin();
89		sf = sf_buf_alloc(ma[offset >> PAGE_SHIFT], SFB_CPUPRIVATE);
90		cp = (char *)sf_buf_kva(sf) + page_offset;
91		switch (uio->uio_segflg) {
92		case UIO_USERSPACE:
93			maybe_yield();
94			if (uio->uio_rw == UIO_READ)
95				error = copyout(cp, iov->iov_base, cnt);
96			else
97				error = copyin(iov->iov_base, cp, cnt);
98			if (error) {
99				sf_buf_free(sf);
100				sched_unpin();
101				goto out;
102			}
103			break;
104		case UIO_SYSSPACE:
105			if (uio->uio_rw == UIO_READ)
106				bcopy(cp, iov->iov_base, cnt);
107			else
108				bcopy(iov->iov_base, cp, cnt);
109			break;
110		case UIO_NOCOPY:
111			break;
112		}
113		sf_buf_free(sf);
114		sched_unpin();
115		iov->iov_base = (char *)iov->iov_base + cnt;
116		iov->iov_len -= cnt;
117		uio->uio_resid -= cnt;
118		uio->uio_offset += cnt;
119		offset += cnt;
120		n -= cnt;
121	}
122out:
123	if (save == 0)
124		td->td_pflags &= ~TDP_DEADLKTREAT;
125	return (error);
126}
127