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/uio.h>
45#include <sys/sf_buf.h>
46
47#include <vm/vm.h>
48#include <vm/vm_page.h>
49
50#include <machine/cpu.h>
51#include <machine/vmparam.h>
52#include <machine/md_var.h>
53
54/*
55 * Implement uiomove(9) from physical memory using sf_bufs to
56 * avoid 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 thread *td = curthread;
62	struct iovec *iov;
63	void *cp;
64	vm_offset_t page_offset;
65	vm_page_t m;
66	size_t cnt;
67	int error = 0;
68	int save = 0;
69	struct sf_buf *sf;
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	KASSERT(uio->uio_resid >= 0,
76	    ("%s: uio %p resid underflow", __func__, uio));
77
78	save = td->td_pflags & TDP_DEADLKTREAT;
79	td->td_pflags |= TDP_DEADLKTREAT;
80	while (n > 0 && uio->uio_resid) {
81		KASSERT(uio->uio_iovcnt > 0,
82		    ("%s: uio %p iovcnt underflow", __func__, uio));
83
84		iov = uio->uio_iov;
85		cnt = iov->iov_len;
86		if (cnt == 0) {
87			uio->uio_iov++;
88			uio->uio_iovcnt--;
89			continue;
90		}
91		if (cnt > n)
92			cnt = n;
93		page_offset = offset & PAGE_MASK;
94		cnt = min(cnt, PAGE_SIZE - page_offset);
95
96		m = ma[offset >> PAGE_SHIFT];
97		sf = sf_buf_alloc(m, 0);
98		cp = (char*)sf_buf_kva(sf) + page_offset;
99
100		switch (uio->uio_segflg) {
101			case UIO_USERSPACE:
102				maybe_yield();
103				switch (uio->uio_rw) {
104				case UIO_READ:
105					error = copyout(cp, iov->iov_base, cnt);
106					break;
107				case UIO_WRITE:
108					error = copyin(iov->iov_base, cp, cnt);
109					break;
110				}
111				if (error) {
112					sf_buf_free(sf);
113					goto out;
114				}
115				break;
116			case UIO_SYSSPACE:
117				switch (uio->uio_rw) {
118				case UIO_READ:
119					bcopy(cp, iov->iov_base, cnt);
120					break;
121				case UIO_WRITE:
122					bcopy(iov->iov_base, cp, cnt);
123					break;
124				}
125				break;
126			case UIO_NOCOPY:
127				break;
128		}
129		sf_buf_free(sf);
130		iov->iov_base = (char *)iov->iov_base + cnt;
131		iov->iov_len -= cnt;
132		uio->uio_resid -= cnt;
133		uio->uio_offset += cnt;
134		offset += cnt;
135		n -= cnt;
136	}
137out:
138	if (save == 0)
139		td->td_pflags &= ~TDP_DEADLKTREAT;
140	return (error);
141}
142