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/sched.h>
45 #include <sys/sf_buf.h>
46 #include <sys/uio.h>
47
48 #include <vm/vm.h>
49 #include <vm/vm_page.h>
50
51 /*
52 * Implement uiomove(9) from physical memory using sf_bufs to reduce
53 * the creation and destruction of ephemeral mappings.
54 */
55 int
uiomove_fromphys(vm_page_t ma[],vm_offset_t offset,int n,struct uio * uio)56 uiomove_fromphys(vm_page_t ma[], vm_offset_t offset, int n, struct uio *uio)
57 {
58 struct sf_buf *sf;
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
67 KASSERT(uio->uio_rw == UIO_READ || uio->uio_rw == UIO_WRITE,
68 ("uiomove_fromphys: mode"));
69 KASSERT(uio->uio_segflg != UIO_USERSPACE || uio->uio_td == curthread,
70 ("uiomove_fromphys proc"));
71 KASSERT(uio->uio_resid >= 0,
72 ("%s: uio %p resid underflow", __func__, uio));
73
74 save = td->td_pflags & TDP_DEADLKTREAT;
75 td->td_pflags |= TDP_DEADLKTREAT;
76 while (n > 0 && uio->uio_resid) {
77 KASSERT(uio->uio_iovcnt > 0,
78 ("%s: uio %p iovcnt underflow", __func__, uio));
79
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 sched_pin();
92 sf = sf_buf_alloc(ma[offset >> PAGE_SHIFT], SFB_CPUPRIVATE);
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 sched_unpin();
108 goto out;
109 }
110 break;
111 case UIO_SYSSPACE:
112 switch (uio->uio_rw) {
113 case UIO_READ:
114 bcopy(cp, iov->iov_base, cnt);
115 break;
116 case UIO_WRITE:
117 bcopy(iov->iov_base, cp, cnt);
118 break;
119 }
120 break;
121 case UIO_NOCOPY:
122 break;
123 }
124 sf_buf_free(sf);
125 sched_unpin();
126 iov->iov_base = (char *)iov->iov_base + cnt;
127 iov->iov_len -= cnt;
128 uio->uio_resid -= cnt;
129 uio->uio_offset += cnt;
130 offset += cnt;
131 n -= cnt;
132 }
133 out:
134 if (save == 0)
135 td->td_pflags &= ~TDP_DEADLKTREAT;
136 return (error);
137 }
138