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/kernel.h>
40 #include <sys/lock.h>
41 #include <sys/mutex.h>
42 #include <sys/proc.h>
43 #include <sys/systm.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/vmparam.h>
51
52 /*
53 * Implement uiomove(9) from physical memory using sf_bufs to
54 * avoid the creation and destruction of ephemeral mappings.
55 */
56 int
uiomove_fromphys(vm_page_t ma[],vm_offset_t offset,int n,struct uio * uio)57 uiomove_fromphys(vm_page_t ma[], vm_offset_t offset, int n, struct uio *uio)
58 {
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 struct sf_buf *sf;
67
68 KASSERT(uio->uio_rw == UIO_READ || uio->uio_rw == UIO_WRITE,
69 ("uiomove_fromphys: mode"));
70 KASSERT(uio->uio_segflg != UIO_USERSPACE || uio->uio_td == curthread,
71 ("uiomove_fromphys proc"));
72 KASSERT(uio->uio_resid >= 0,
73 ("%s: uio %p resid underflow", __func__, uio));
74
75 save = td->td_pflags & TDP_DEADLKTREAT;
76 td->td_pflags |= TDP_DEADLKTREAT;
77 while (n > 0 && uio->uio_resid) {
78 KASSERT(uio->uio_iovcnt > 0,
79 ("%s: uio %p iovcnt underflow", __func__, uio));
80
81 iov = uio->uio_iov;
82 cnt = iov->iov_len;
83 if (cnt == 0) {
84 uio->uio_iov++;
85 uio->uio_iovcnt--;
86 continue;
87 }
88 if (cnt > n)
89 cnt = n;
90 page_offset = offset & PAGE_MASK;
91 cnt = min(cnt, PAGE_SIZE - page_offset);
92 sf = sf_buf_alloc(ma[offset >> PAGE_SHIFT], 0);
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 goto out;
108 }
109 break;
110 case UIO_SYSSPACE:
111 switch (uio->uio_rw) {
112 case UIO_READ:
113 bcopy(cp, iov->iov_base, cnt);
114 break;
115 case UIO_WRITE:
116 bcopy(iov->iov_base, cp, cnt);
117 break;
118 }
119 break;
120 case UIO_NOCOPY:
121 break;
122 }
123 sf_buf_free(sf);
124 iov->iov_base = (char *)iov->iov_base + cnt;
125 iov->iov_len -= cnt;
126 uio->uio_resid -= cnt;
127 uio->uio_offset += cnt;
128 offset += cnt;
129 n -= cnt;
130 }
131 out:
132 if (save == 0)
133 td->td_pflags &= ~TDP_DEADLKTREAT;
134 return (error);
135 }
136