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/systm.h>
45 #include <sys/kernel.h>
46 #include <sys/lock.h>
47 #include <sys/mutex.h>
48 #include <sys/proc.h>
49 #include <sys/sched.h>
50 #include <sys/sf_buf.h>
51 #include <sys/uio.h>
52
53 #include <vm/vm.h>
54 #include <vm/vm_page.h>
55
56 /*
57 * Implement uiomove(9) from physical memory using sf_bufs to reduce
58 * the creation and destruction of ephemeral mappings.
59 */
60 int
61 uiomove_fromphys(vm_page_t ma[], vm_offset_t offset, int n, struct uio *uio)
62 {
63 struct sf_buf *sf;
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
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 while (n > 0 && uio->uio_resid) {
79 iov = uio->uio_iov;
80 cnt = iov->iov_len;
81 if (cnt == 0) {
82 uio->uio_iov++;
83 uio->uio_iovcnt--;
84 continue;
85 }
86 if (cnt > n)
87 cnt = n;
88 page_offset = offset & PAGE_MASK;
89 cnt = min(cnt, PAGE_SIZE - page_offset);
90 sched_pin();
91 sf = sf_buf_alloc(ma[offset >> PAGE_SHIFT], SFB_CPUPRIVATE);
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 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 }
124 out:
125 if (save == 0)
126 td->td_pflags &= ~TDP_DEADLKTREAT;
127 return (error);
128 }
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