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
38#include <sys/param.h>
39#include <sys/systm.h>
40#include <sys/kernel.h>
41#include <sys/lock.h>
42#include <sys/mutex.h>
43#include <sys/proc.h>
44#include <sys/sched.h>
45#include <sys/sf_buf.h>
46#include <sys/uio.h>
47
48#include <vm/vm.h>
49#include <vm/vm_page.h>
50
51/*
52 * Implement uiomove(9) from physical memory using sf_bufs to reduce
53 * the creation and destruction of ephemeral mappings.
54 */
55int
56uiomove_fromphys(vm_page_t ma[], vm_offset_t offset, int n, struct uio *uio)
57{
58	struct sf_buf *sf;
59	struct thread *td = curthread;
60	struct iovec *iov;
61	void *cp;
62	vm_offset_t page_offset;
63	size_t cnt;
64	int error = 0;
65	int save = 0;
66
67	KASSERT(uio->uio_rw == UIO_READ || uio->uio_rw == UIO_WRITE,
68	    ("uiomove_fromphys: mode"));
69	KASSERT(uio->uio_segflg != UIO_USERSPACE || uio->uio_td == curthread,
70	    ("uiomove_fromphys proc"));
71	KASSERT(uio->uio_resid >= 0,
72	    ("%s: uio %p resid underflow", __func__, uio));
73
74	save = td->td_pflags & TDP_DEADLKTREAT;
75	td->td_pflags |= TDP_DEADLKTREAT;
76	while (n > 0 && uio->uio_resid) {
77		KASSERT(uio->uio_iovcnt > 0,
78		    ("%s: uio %p iovcnt underflow", __func__, uio));
79
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		sched_pin();
92		sf = sf_buf_alloc(ma[offset >> PAGE_SHIFT], SFB_CPUPRIVATE);
93		cp = (char *)sf_buf_kva(sf) + page_offset;
94		switch (uio->uio_segflg) {
95		case UIO_USERSPACE:
96			maybe_yield();
97			switch (uio->uio_rw) {
98			case UIO_READ:
99				error = copyout(cp, iov->iov_base, cnt);
100				break;
101			case UIO_WRITE:
102				error = copyin(iov->iov_base, cp, cnt);
103				break;
104			}
105			if (error) {
106				sf_buf_free(sf);
107				sched_unpin();
108				goto out;
109			}
110			break;
111		case UIO_SYSSPACE:
112			switch (uio->uio_rw) {
113			case UIO_READ:
114				bcopy(cp, iov->iov_base, cnt);
115				break;
116			case UIO_WRITE:
117				bcopy(iov->iov_base, cp, cnt);
118				break;
119			}
120			break;
121		case UIO_NOCOPY:
122			break;
123		}
124		sf_buf_free(sf);
125		sched_unpin();
126		iov->iov_base = (char *)iov->iov_base + cnt;
127		iov->iov_len -= cnt;
128		uio->uio_resid -= cnt;
129		uio->uio_offset += cnt;
130		offset += cnt;
131		n -= cnt;
132	}
133out:
134	if (save == 0)
135		td->td_pflags &= ~TDP_DEADLKTREAT;
136	return (error);
137}
138