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("$FreeBSD$");
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
51#include <vm/vm.h>
52#include <vm/vm_page.h>
53
54#include <machine/vmparam.h>
55
56/*
57 * Implement uiomove(9) from physical memory using the direct map to
58 * avoid the creation and destruction of ephemeral mappings.
59 */
60int
61uiomove_fromphys(vm_page_t ma[], vm_offset_t offset, int n, struct uio *uio)
62{
63	struct thread *td = curthread;
64	struct iovec *iov;
65	void *cp;
66	vm_offset_t page_offset, vaddr;
67	size_t cnt;
68	int error = 0;
69	int save = 0;
70	boolean_t mapped;
71
72	KASSERT(uio->uio_rw == UIO_READ || uio->uio_rw == UIO_WRITE,
73	    ("uiomove_fromphys: mode"));
74	KASSERT(uio->uio_segflg != UIO_USERSPACE || uio->uio_td == curthread,
75	    ("uiomove_fromphys proc"));
76	save = td->td_pflags & TDP_DEADLKTREAT;
77	td->td_pflags |= TDP_DEADLKTREAT;
78	mapped = FALSE;
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		if (uio->uio_segflg != UIO_NOCOPY) {
92			mapped = pmap_map_io_transient(
93			    &ma[offset >> PAGE_SHIFT], &vaddr, 1, TRUE);
94			cp = (char *)vaddr + page_offset;
95		}
96		switch (uio->uio_segflg) {
97		case UIO_USERSPACE:
98			maybe_yield();
99			if (uio->uio_rw == UIO_READ)
100				error = copyout(cp, iov->iov_base, cnt);
101			else
102				error = copyin(iov->iov_base, cp, cnt);
103			if (error)
104				goto out;
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		if (__predict_false(mapped)) {
116			pmap_unmap_io_transient(&ma[offset >> PAGE_SHIFT],
117			    &vaddr, 1, TRUE);
118			mapped = FALSE;
119		}
120		iov->iov_base = (char *)iov->iov_base + cnt;
121		iov->iov_len -= cnt;
122		uio->uio_resid -= cnt;
123		uio->uio_offset += cnt;
124		offset += cnt;
125		n -= cnt;
126	}
127out:
128	if (__predict_false(mapped))
129		pmap_unmap_io_transient(&ma[offset >> PAGE_SHIFT], &vaddr, 1,
130		    TRUE);
131	if (save == 0)
132		td->td_pflags &= ~TDP_DEADLKTREAT;
133	return (error);
134}
135