uio_machdep.c revision 178172 
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 * 4. 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 *	from: src/sys/i386/i386/uio_machdep.c,v 1.8 2005/02/13 23:09:36 alc
37 */
38
39#include <sys/cdefs.h>
40__FBSDID("$FreeBSD: head/sys/mips/mips/uio_machdep.c 178172 2008-04-13 07:27:37Z imp $");
41
42#include <sys/param.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/systm.h>
50#include <sys/uio.h>
51
52#include <vm/vm.h>
53#include <vm/vm_page.h>
54
55/*
56 * Implement uiomove(9) from physical memory using sf_bufs to reduce
57 * the creation and destruction of ephemeral mappings.
58 */
59int
60uiomove_fromphys(vm_page_t ma[], vm_offset_t offset, int n, struct uio *uio)
61{
62	struct sf_buf *sf;
63	struct thread *td = curthread;
64	struct iovec *iov;
65	void *cp;
66	vm_offset_t page_offset;
67	size_t cnt;
68	int error = 0;
69	int save = 0;
70
71	KASSERT(uio->uio_rw == UIO_READ || uio->uio_rw == UIO_WRITE,
72	    ("uiomove_fromphys: mode"));
73	KASSERT(uio->uio_segflg != UIO_USERSPACE || uio->uio_td == curthread,
74	    ("uiomove_fromphys proc"));
75	save = td->td_pflags & TDP_DEADLKTREAT;
76	td->td_pflags |= TDP_DEADLKTREAT;
77	while (n > 0 && uio->uio_resid) {
78		iov = uio->uio_iov;
79		cnt = iov->iov_len;
80		if (cnt == 0) {
81			uio->uio_iov++;
82			uio->uio_iovcnt--;
83			continue;
84		}
85		if (cnt > n)
86			cnt = n;
87		page_offset = offset & PAGE_MASK;
88		cnt = min(cnt, PAGE_SIZE - page_offset);
89		sched_pin();
90		sf = sf_buf_alloc(ma[offset >> PAGE_SHIFT], SFB_CPUPRIVATE);
91		cp = (char *)sf_buf_kva(sf) + page_offset;
92		switch (uio->uio_segflg) {
93		case UIO_USERSPACE:
94			if (ticks - PCPU_GET(switchticks) >= hogticks)
95				uio_yield();
96			if (uio->uio_rw == UIO_READ)
97				error = copyout(cp, iov->iov_base, cnt);
98			else
99				error = copyin(iov->iov_base, cp, cnt);
100			if (error) {
101				sf_buf_free(sf);
102				sched_unpin();
103				goto out;
104			}
105			break;
106		case UIO_SYSSPACE:
107			if (uio->uio_rw == UIO_READ)
108				bcopy(cp, iov->iov_base, cnt);
109			else
110				bcopy(iov->iov_base, cp, cnt);
111			break;
112		case UIO_NOCOPY:
113			break;
114		}
115		sf_buf_free(sf);
116		sched_unpin();
117		iov->iov_base = (char *)iov->iov_base + cnt;
118		iov->iov_len -= cnt;
119		uio->uio_resid -= cnt;
120		uio->uio_offset += cnt;
121		offset += cnt;
122		n -= cnt;
123	}
124out:
125	if (save == 0)
126		td->td_pflags &= ~TDP_DEADLKTREAT;
127	return (error);
128}
129