1*8d6196f9Schs /* $NetBSD: uvm_io.c,v 1.29 2020/09/21 18:41:59 chs Exp $ */
2f2caacc7Smrg
3f2caacc7Smrg /*
4f2caacc7Smrg * Copyright (c) 1997 Charles D. Cranor and Washington University.
5f2caacc7Smrg * All rights reserved.
6f2caacc7Smrg *
7f2caacc7Smrg * Redistribution and use in source and binary forms, with or without
8f2caacc7Smrg * modification, are permitted provided that the following conditions
9f2caacc7Smrg * are met:
10f2caacc7Smrg * 1. Redistributions of source code must retain the above copyright
11f2caacc7Smrg * notice, this list of conditions and the following disclaimer.
12f2caacc7Smrg * 2. Redistributions in binary form must reproduce the above copyright
13f2caacc7Smrg * notice, this list of conditions and the following disclaimer in the
14f2caacc7Smrg * documentation and/or other materials provided with the distribution.
15f2caacc7Smrg *
16f2caacc7Smrg * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17f2caacc7Smrg * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18f2caacc7Smrg * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19f2caacc7Smrg * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20f2caacc7Smrg * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
21f2caacc7Smrg * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22f2caacc7Smrg * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23f2caacc7Smrg * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24f2caacc7Smrg * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
25f2caacc7Smrg * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
261f6b921cSmrg *
271f6b921cSmrg * from: Id: uvm_io.c,v 1.1.2.2 1997/12/30 12:02:00 mrg Exp
28f2caacc7Smrg */
29f2caacc7Smrg
30f2caacc7Smrg /*
31f2caacc7Smrg * uvm_io.c: uvm i/o ops
32f2caacc7Smrg */
33f2caacc7Smrg
34b616d1caSlukem #include <sys/cdefs.h>
35*8d6196f9Schs __KERNEL_RCSID(0, "$NetBSD: uvm_io.c,v 1.29 2020/09/21 18:41:59 chs Exp $");
36b616d1caSlukem
37f2caacc7Smrg #include <sys/param.h>
38f2caacc7Smrg #include <sys/systm.h>
39f2caacc7Smrg #include <sys/mman.h>
40f2caacc7Smrg #include <sys/uio.h>
41f2caacc7Smrg
42f2caacc7Smrg #include <uvm/uvm.h>
43f2caacc7Smrg
44f2caacc7Smrg /*
45f2caacc7Smrg * functions
46f2caacc7Smrg */
47f2caacc7Smrg
48f2caacc7Smrg /*
49f2caacc7Smrg * uvm_io: perform I/O on a map
50f2caacc7Smrg *
51f2caacc7Smrg * => caller must have a reference to "map" so that it doesn't go away
52f2caacc7Smrg * while we are working.
53f2caacc7Smrg */
54f2caacc7Smrg
558106d135Smrg int
uvm_io(struct vm_map * map,struct uio * uio,int flags)561b7c20bdSchristos uvm_io(struct vm_map *map, struct uio *uio, int flags)
57f2caacc7Smrg {
58a2dd74edSeeh vaddr_t baseva, endva, pageoffset, kva;
59a2dd74edSeeh vsize_t chunksz, togo, sz;
60821ec03eSchs struct vm_map_entry *dead_entries;
61f2caacc7Smrg int error;
62f2caacc7Smrg
63f2caacc7Smrg /*
64f2caacc7Smrg * step 0: sanity checks and set up for copy loop. start with a
65f2caacc7Smrg * large chunk size. if we have trouble finding vm space we will
66f2caacc7Smrg * reduce it.
67f2caacc7Smrg */
68f2caacc7Smrg
69f2caacc7Smrg if (uio->uio_resid == 0)
70f2caacc7Smrg return(0);
71f2caacc7Smrg togo = uio->uio_resid;
72f2caacc7Smrg
73a2dd74edSeeh baseva = (vaddr_t) uio->uio_offset;
74f2caacc7Smrg endva = baseva + (togo - 1);
75f2caacc7Smrg
76f2caacc7Smrg if (endva < baseva) /* wrap around? */
77f2caacc7Smrg return(EIO);
78f2caacc7Smrg
79f2caacc7Smrg if (baseva >= VM_MAXUSER_ADDRESS)
80f2caacc7Smrg return(0);
81f2caacc7Smrg if (endva >= VM_MAXUSER_ADDRESS)
828106d135Smrg /* EOF truncate */
838106d135Smrg togo = togo - (endva - VM_MAXUSER_ADDRESS + 1);
84f2caacc7Smrg pageoffset = baseva & PAGE_MASK;
85f2caacc7Smrg baseva = trunc_page(baseva);
8685c8cfb5Stls chunksz = MIN(round_page(togo + pageoffset), trunc_page(MAXPHYS));
87f2caacc7Smrg error = 0;
88f2caacc7Smrg
891b7c20bdSchristos flags |= UVM_EXTRACT_QREF | UVM_EXTRACT_CONTIG | UVM_EXTRACT_FIXPROT;
90*8d6196f9Schs
91*8d6196f9Schs /* XXX cannot use QREF with without AMAP_REFALL, and REFALL is unsafe */
92*8d6196f9Schs flags &= ~UVM_EXTRACT_QREF;
93*8d6196f9Schs
94f2caacc7Smrg /*
95f2caacc7Smrg * step 1: main loop... while we've got data to move
96f2caacc7Smrg */
97f2caacc7Smrg
98f2caacc7Smrg for (/*null*/; togo > 0 ; pageoffset = 0) {
99f2caacc7Smrg
100f2caacc7Smrg /*
101f2caacc7Smrg * step 2: extract mappings from the map into kernel_map
102f2caacc7Smrg */
103f2caacc7Smrg
104f2caacc7Smrg error = uvm_map_extract(map, baseva, chunksz, kernel_map, &kva,
1051b7c20bdSchristos flags);
106f2caacc7Smrg if (error) {
107f2caacc7Smrg
108f2caacc7Smrg /* retry with a smaller chunk... */
109f2caacc7Smrg if (error == ENOMEM && chunksz > PAGE_SIZE) {
110f2caacc7Smrg chunksz = trunc_page(chunksz / 2);
111f2caacc7Smrg if (chunksz < PAGE_SIZE)
112f2caacc7Smrg chunksz = PAGE_SIZE;
113f2caacc7Smrg continue;
114f2caacc7Smrg }
115f2caacc7Smrg
116f2caacc7Smrg break;
117f2caacc7Smrg }
118f2caacc7Smrg
119f2caacc7Smrg /*
120f2caacc7Smrg * step 3: move a chunk of data
121f2caacc7Smrg */
122f2caacc7Smrg
123f2caacc7Smrg sz = chunksz - pageoffset;
124f2caacc7Smrg if (sz > togo)
125f2caacc7Smrg sz = togo;
12653524e44Schristos error = uiomove((void *) (kva + pageoffset), sz, uio);
127f2caacc7Smrg togo -= sz;
128f2caacc7Smrg baseva += chunksz;
129f2caacc7Smrg
130f2caacc7Smrg /*
131f2caacc7Smrg * step 4: unmap the area of kernel memory
132f2caacc7Smrg */
133f2caacc7Smrg
134f2caacc7Smrg vm_map_lock(kernel_map);
1351207308bSyamt uvm_unmap_remove(kernel_map, kva, kva + chunksz, &dead_entries,
13655b033b1Spara 0);
137f2caacc7Smrg vm_map_unlock(kernel_map);
138f2caacc7Smrg if (dead_entries != NULL)
139f2caacc7Smrg uvm_unmap_detach(dead_entries, AMAP_REFALL);
140b794108bSchs
141b794108bSchs if (error)
142b794108bSchs break;
143f2caacc7Smrg }
144f2caacc7Smrg return (error);
145f2caacc7Smrg }
146