1 /*-
2 * Copyright (c) 2004 Alan L. Cox <alc@cs.rice.edu>
3 * Copyright (c) 1982, 1986, 1991, 1993
4 * The Regents of the University of California. All rights reserved.
5 * (c) UNIX System Laboratories, Inc.
6 * All or some portions of this file are derived from material licensed
7 * to the University of California by American Telephone and Telegraph
8 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
9 * the permission of UNIX System Laboratories, Inc.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 * 3. Neither the name of the University nor the names of its contributors
20 * may be used to endorse or promote products derived from this software
21 * without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 *
35 * @(#)kern_subr.c 8.3 (Berkeley) 1/21/94
36 */
37
38 #include <sys/cdefs.h>
39 __FBSDID("$FreeBSD: releng/11.2/sys/i386/i386/uio_machdep.c 331722 2018-03-29 02:50:57Z eadler $");
40
41 #include <sys/param.h>
42 #include <sys/systm.h>
43 #include <sys/kernel.h>
44 #include <sys/lock.h>
45 #include <sys/mutex.h>
46 #include <sys/proc.h>
47 #include <sys/sched.h>
48 #include <sys/sf_buf.h>
49 #include <sys/uio.h>
50
51 #include <vm/vm.h>
52 #include <vm/vm_page.h>
53
54 /*
55 * Implement uiomove(9) from physical memory using sf_bufs to reduce
56 * the creation and destruction of ephemeral mappings.
57 */
58 int
59 uiomove_fromphys(vm_page_t ma[], vm_offset_t offset, int n, struct uio *uio)
60 {
61 struct sf_buf *sf;
62 struct thread *td = curthread;
63 struct iovec *iov;
64 void *cp;
65 vm_offset_t page_offset;
66 size_t cnt;
67 int error = 0;
68 int save = 0;
69
70 KASSERT(uio->uio_rw == UIO_READ || uio->uio_rw == UIO_WRITE,
71 ("uiomove_fromphys: mode"));
72 KASSERT(uio->uio_segflg != UIO_USERSPACE || uio->uio_td == curthread,
73 ("uiomove_fromphys proc"));
74 save = td->td_pflags & TDP_DEADLKTREAT;
75 td->td_pflags |= TDP_DEADLKTREAT;
76 while (n > 0 && uio->uio_resid) {
77 iov = uio->uio_iov;
78 cnt = iov->iov_len;
79 if (cnt == 0) {
80 uio->uio_iov++;
81 uio->uio_iovcnt--;
82 continue;
83 }
84 if (cnt > n)
85 cnt = n;
86 page_offset = offset & PAGE_MASK;
87 cnt = min(cnt, PAGE_SIZE - page_offset);
88 sched_pin();
89 sf = sf_buf_alloc(ma[offset >> PAGE_SHIFT], SFB_CPUPRIVATE);
90 cp = (char *)sf_buf_kva(sf) + page_offset;
91 switch (uio->uio_segflg) {
92 case UIO_USERSPACE:
93 maybe_yield();
94 if (uio->uio_rw == UIO_READ)
95 error = copyout(cp, iov->iov_base, cnt);
96 else
97 error = copyin(iov->iov_base, cp, cnt);
98 if (error) {
99 sf_buf_free(sf);
100 sched_unpin();
101 goto out;
102 }
103 break;
104 case UIO_SYSSPACE:
105 if (uio->uio_rw == UIO_READ)
106 bcopy(cp, iov->iov_base, cnt);
107 else
108 bcopy(iov->iov_base, cp, cnt);
109 break;
110 case UIO_NOCOPY:
111 break;
112 }
113 sf_buf_free(sf);
114 sched_unpin();
115 iov->iov_base = (char *)iov->iov_base + cnt;
116 iov->iov_len -= cnt;
117 uio->uio_resid -= cnt;
118 uio->uio_offset += cnt;
119 offset += cnt;
120 n -= cnt;
121 }
122 out:
123 if (save == 0)
124 td->td_pflags &= ~TDP_DEADLKTREAT;
125 return (error);
126 }
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