uio_machdep.c revision 330897 
1/*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 2004 Alan L. Cox <alc@cs.rice.edu>
5 * Copyright (c) 1982, 1986, 1991, 1993
6 *	The Regents of the University of California.  All rights reserved.
7 * (c) UNIX System Laboratories, Inc.
8 * All or some portions of this file are derived from material licensed
9 * to the University of California by American Telephone and Telegraph
10 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
11 * the permission of UNIX System Laboratories, Inc.
12 *
13 * Redistribution and use in source and binary forms, with or without
14 * modification, are permitted provided that the following conditions
15 * are met:
16 * 1. Redistributions of source code must retain the above copyright
17 *    notice, this list of conditions and the following disclaimer.
18 * 2. Redistributions in binary form must reproduce the above copyright
19 *    notice, this list of conditions and the following disclaimer in the
20 *    documentation and/or other materials provided with the distribution.
21 * 3. Neither the name of the University nor the names of its contributors
22 *    may be used to endorse or promote products derived from this software
23 *    without specific prior written permission.
24 *
25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
28 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35 * SUCH DAMAGE.
36 *
37 *	@(#)kern_subr.c	8.3 (Berkeley) 1/21/94
38 */
39
40#include <sys/cdefs.h>
41__FBSDID("$FreeBSD: stable/11/sys/arm/arm/uio_machdep.c 330897 2018-03-14 03:19:51Z eadler $");
42
43#include <sys/param.h>
44#include <sys/kernel.h>
45#include <sys/lock.h>
46#include <sys/mutex.h>
47#include <sys/proc.h>
48#include <sys/systm.h>
49#include <sys/uio.h>
50#include <sys/sf_buf.h>
51
52#include <vm/vm.h>
53#include <vm/vm_page.h>
54
55#include <machine/vmparam.h>
56
57/*
58 * Implement uiomove(9) from physical memory using sf_bufs to
59 * avoid the creation and destruction of ephemeral mappings.
60 */
61int
62uiomove_fromphys(vm_page_t ma[], vm_offset_t offset, int n, struct uio *uio)
63{
64	struct thread *td = curthread;
65	struct iovec *iov;
66	void *cp;
67	vm_offset_t page_offset;
68	size_t cnt;
69	int error = 0;
70	int save = 0;
71	struct sf_buf *sf;
72
73	KASSERT(uio->uio_rw == UIO_READ || uio->uio_rw == UIO_WRITE,
74	    ("uiomove_fromphys: mode"));
75	KASSERT(uio->uio_segflg != UIO_USERSPACE || uio->uio_td == curthread,
76	    ("uiomove_fromphys proc"));
77	save = td->td_pflags & TDP_DEADLKTREAT;
78	td->td_pflags |= TDP_DEADLKTREAT;
79	while (n > 0 && uio->uio_resid) {
80		iov = uio->uio_iov;
81		cnt = iov->iov_len;
82		if (cnt == 0) {
83			uio->uio_iov++;
84			uio->uio_iovcnt--;
85			continue;
86		}
87		if (cnt > n)
88			cnt = n;
89		page_offset = offset & PAGE_MASK;
90		cnt = min(cnt, PAGE_SIZE - page_offset);
91		sf = sf_buf_alloc(ma[offset >> PAGE_SHIFT], 0);
92		cp = (char*)sf_buf_kva(sf) + page_offset;
93		switch (uio->uio_segflg) {
94		case UIO_USERSPACE:
95			maybe_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				goto out;
103			}
104			break;
105		case UIO_SYSSPACE:
106			if (uio->uio_rw == UIO_READ)
107				bcopy(cp, iov->iov_base, cnt);
108			else
109				bcopy(iov->iov_base, cp, cnt);
110			break;
111		case UIO_NOCOPY:
112			break;
113		}
114		sf_buf_free(sf);
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