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 */
58 int
uiomove_fromphys(vm_page_t ma[],vm_offset_t offset,int n,struct uio * uio)59 uiomove_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 }
137 out:
138 if (save == 0)
139 td->td_pflags &= ~TDP_DEADLKTREAT;
140 return (error);
141 }
142