1 /*
2 * Copyright (c) 1988 University of Utah.
3 * Copyright (c) 1982, 1986, 1990, 1993
4 * The Regents of the University of California. All rights reserved.
5 *
6 * This code is derived from software contributed to Berkeley by
7 * the Systems Programming Group of the University of Utah Computer
8 * Science Department.
9 *
10 * %sccs.include.redist.c%
11 *
12 * from: Utah $Hdr: mem.c 1.14 90/10/12$
13 * from: hp300/hp300/mem.c 8.2 (Berkeley) 11/14/93
14 *
15 * @(#)mem.c 8.1 (Berkeley) 12/06/93
16 */
17
18 /*
19 * Memory special file
20 */
21
22 #include <sys/param.h>
23 #include <sys/conf.h>
24 #include <sys/buf.h>
25 #include <sys/systm.h>
26 #include <sys/malloc.h>
27
28 #include <machine/cpu.h>
29 #include <machine/stinger.h>
30
31 #include <vm/vm_param.h>
32 #include <vm/lock.h>
33 #include <vm/vm_prot.h>
34 #include <vm/pmap.h>
35
36 extern u_int lowram;
37 caddr_t zeropage;
38
39 /*ARGSUSED*/
mmrw(dev,uio,flags)40 mmrw(dev, uio, flags)
41 dev_t dev;
42 struct uio *uio;
43 int flags;
44 {
45 register int o;
46 register u_int c, v;
47 register struct iovec *iov;
48 int error = 0;
49 int kernloc;
50
51 while (uio->uio_resid > 0 && error == 0) {
52 iov = uio->uio_iov;
53 if (iov->iov_len == 0) {
54 uio->uio_iov++;
55 uio->uio_iovcnt--;
56 if (uio->uio_iovcnt < 0)
57 panic("mmrw");
58 continue;
59 }
60 switch (minor(dev)) {
61
62 /* minor device 0 is physical memory */
63 case 0:
64 v = uio->uio_offset;
65 #ifndef DEBUG
66 /* allow reads only in RAM (except for DEBUG) */
67 if (v >= 0xFFFFFFFC || v < lowram)
68 return (EFAULT);
69 #endif
70 pmap_enter(kernel_pmap, (vm_offset_t)vmmap,
71 trunc_page(v), uio->uio_rw == UIO_READ ?
72 VM_PROT_READ : VM_PROT_WRITE, TRUE);
73 o = (int)uio->uio_offset & PGOFSET;
74 c = (u_int)(NBPG - ((int)iov->iov_base & PGOFSET));
75 c = min(c, (u_int)(NBPG - o));
76 c = min(c, (u_int)iov->iov_len);
77 error = uiomove((caddr_t)&vmmap[o], (int)c, uio);
78 pmap_remove(kernel_pmap, (vm_offset_t)vmmap,
79 (vm_offset_t)&vmmap[NBPG]);
80 continue;
81
82 /* minor device 1 is kernel memory */
83 case 1:
84 kernloc = uio->uio_offset;
85 c = min(iov->iov_len, MAXPHYS);
86 if (!kernacc((caddr_t)kernloc, c,
87 uio->uio_rw == UIO_READ ? B_READ : B_WRITE))
88 return (EFAULT);
89 error = uiomove((caddr_t)kernloc, (int)c, uio);
90 continue;
91
92 /* minor device 2 is EOF/RATHOLE */
93 case 2:
94 if (uio->uio_rw == UIO_WRITE)
95 uio->uio_resid = 0;
96 return (0);
97
98 /* minor device 12 (/dev/zero) is source of nulls on read, rathole on write */
99 case 12:
100 if (uio->uio_rw == UIO_WRITE) {
101 c = iov->iov_len;
102 break;
103 }
104 /*
105 * On the first call, allocate and zero a page
106 * of memory for use with /dev/zero.
107 *
108 * XXX on the hp300 we already know where there
109 * is a global zeroed page, the null segment table.
110 */
111 if (zeropage == NULL) {
112 #if CLBYTES == NBPG
113 extern caddr_t Segtabzero;
114 zeropage = Segtabzero;
115 #else
116 zeropage = (caddr_t)
117 malloc(CLBYTES, M_TEMP, M_WAITOK);
118 bzero(zeropage, CLBYTES);
119 #endif
120 }
121 c = min(iov->iov_len, CLBYTES);
122 error = uiomove(zeropage, (int)c, uio);
123 continue;
124
125 default:
126 return (ENXIO);
127 }
128 if (error)
129 break;
130 iov->iov_base += c;
131 iov->iov_len -= c;
132 uio->uio_offset += c;
133 uio->uio_resid -= c;
134 }
135 return (error);
136 }
137
mmmap(dev,off,prot)138 mmmap(dev, off, prot)
139 dev_t dev;
140 {
141 /*
142 * /dev/mem is the only one that makes sense through this
143 * interface. For /dev/kmem any physaddr we return here
144 * could be transient and hence incorrect or invalid at
145 * a later time. /dev/null just doesn't make any sense
146 * and /dev/zero is a hack that is handled via the default
147 * pager in mmap().
148 */
149 if (minor(dev) != 0)
150 return (-1);
151 /*
152 * Allow access only in RAM.
153 *
154 * XXX could be extended to allow access to IO space but must
155 * be very careful.
156 */
157 if ((unsigned)off < lowram ||
158 (unsigned)off >= (unsigned) KernInter.maxaddr)
159 return (-1);
160 return (luna_btop(off));
161 }
162