1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
|
/*
* Copyright (c) 2023-2024 Ian Marco Moffett and the Osmora Team.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of Hyra nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/types.h>
#include <sys/cdefs.h>
#include <sys/errno.h>
#include <sys/syslog.h>
#include <sys/systm.h>
#include <sys/vnode.h>
#include <vm/vm_vnode.h>
#include <vm/vm_page.h>
#include <vm/pmap.h>
#include <vm/vm.h>
#define VN_TIMEOUT_USEC 200000
#define pr_trace(fmt, ...) kprintf("vm_vnode: " fmt, ##__VA_ARGS__)
#define pr_error(...) pr_trace(__VA_ARGS__)
/* Debug print helper */
#if defined(PR_DEBUG)
#define pr_debug(...) pr_trace(__VA_ARGS__)
#else
#define pr_debug(...) __nothing
#endif /* PR_DEBUG */
const struct vm_pagerops vm_vnops;
/*
* Perform read/write operation on vnode to/from pages.
*
* Returns number of bytes read.
*/
static int
vn_io(struct vnode *vp, struct vm_page **pgs, unsigned int npages, int rw)
{
struct vop_getattr_args args;
struct sio_txn sio;
struct vattr vattr;
size_t c, read = 0;
int err;
/* TODO: Add support for writes */
if (rw != 0) {
return -ENOTSUP;
}
args.vp = vp;
args.res = &vattr;
c = MAX(vattr.size / DEFAULT_PAGESIZE, 1);
if ((err = vfs_vop_getattr(vp, &args)) != 0) {
return err;
}
if (npages > c) {
npages = c;
}
/* Prepare SIO constants */
sio.len = DEFAULT_PAGESIZE;
sio.offset = 0;
/* Copy in each page */
for (size_t i = 0; i < npages; ++i) {
sio.buf = PHYS_TO_VIRT(pgs[i]->phys_addr);
read = vfs_vop_read(vp, &sio);
if (read < 0)
pr_debug("vn_io: page-in @ %p failed (err=%d)\n", err);
}
return read;
}
/*
* Get pages from backing store.
*
* @obp: Object representing the backing store.
* @pgs: Page descriptors to be filled.
* @off: Offset to read from in backing store.
* @len: Length to read in bytes.
*/
static int
vn_get(struct vm_object *obp, struct vm_page **pgs, off_t off, size_t len)
{
struct vm_page *pgtmp;
size_t j, pgcnt;
spinlock_acquire(&obp->lock);
for (int i = off; i < len; i += DEFAULT_PAGESIZE) {
j = i / DEFAULT_PAGESIZE;
pgtmp = vm_pagelookup(obp, i);
/*
* If we have no corresponding page in the object
* at this offset, we will need to make our own.
*/
if (pgtmp == NULL) {
pgtmp = vm_pagealloc(obp, PALLOC_ZERO);
if (pgtmp == NULL) {
pgs[j]->flags &= ~PG_VALID;
continue;
}
pgtmp->offset = i;
pgs[j] = pgtmp;
}
if (spinlock_usleep(&pgtmp->lock, VN_TIMEOUT_USEC) != 0) {
pgs[j]->flags &= ~PG_VALID;
continue;
}
/* Set the page count and ensure it is valid */
pgcnt = ALIGN_DOWN(len, DEFAULT_PAGESIZE);
pgcnt = MAX(pgcnt, 1);
/* Page in and save this pgtmp */
vn_io(obp->data, &pgtmp, pgcnt, 0);
pgs[j] = pgtmp;
spinlock_release(&pgtmp->lock);
}
spinlock_release(&obp->lock);
return 0;
}
/*
* Attach a virtual memory object to a vnode.
*
* @vp: Vnode to attach to.
*/
struct vm_object *
vn_attach(struct vnode *vp, vm_prot_t prot)
{
struct vm_object *vmobj;
int error;
if (vp->type != VREG) {
pr_error("vn_attach: vp=%p, prot=%x\n", vp, prot);
pr_error("vn_attach: Special files not supported yet!\n");
return NULL;
}
error = vm_obj_init(&vp->vobj, &vm_vnops, 1);
if (error != 0) {
return NULL;
}
vmobj = &vp->vobj;
vmobj->prot = prot;
vmobj->data = vp;
vmobj->pgops = &vm_vnops;
return vmobj;
}
const struct vm_pagerops vm_vnops = {
.get = vn_get
};
|
