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const-ify make segment ops structures
There is no reason to keep the segment ops structures writable.
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--- old/usr/src/uts/common/os/urw.c
+++ new/usr/src/uts/common/os/urw.c
1 1 /*
2 2 * CDDL HEADER START
3 3 *
4 4 * The contents of this file are subject to the terms of the
5 5 * Common Development and Distribution License (the "License").
6 6 * You may not use this file except in compliance with the License.
7 7 *
8 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 9 * or http://www.opensolaris.org/os/licensing.
10 10 * See the License for the specific language governing permissions
11 11 * and limitations under the License.
12 12 *
13 13 * When distributing Covered Code, include this CDDL HEADER in each
14 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 15 * If applicable, add the following below this CDDL HEADER, with the
16 16 * fields enclosed by brackets "[]" replaced with your own identifying
17 17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 18 *
19 19 * CDDL HEADER END
20 20 */
21 21 /*
22 22 * Copyright 2007 Sun Microsystems, Inc. All rights reserved.
23 23 * Use is subject to license terms.
24 24 */
25 25
26 26 /* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
27 27 /* All Rights Reserved */
28 28
29 29 #pragma ident "%Z%%M% %I% %E% SMI"
30 30
31 31 #include <sys/atomic.h>
32 32 #include <sys/errno.h>
33 33 #include <sys/stat.h>
34 34 #include <sys/modctl.h>
35 35 #include <sys/conf.h>
36 36 #include <sys/systm.h>
37 37 #include <sys/ddi.h>
38 38 #include <sys/sunddi.h>
39 39 #include <sys/cpuvar.h>
40 40 #include <sys/kmem.h>
41 41 #include <sys/strsubr.h>
42 42 #include <sys/sysmacros.h>
43 43 #include <sys/frame.h>
44 44 #include <sys/stack.h>
45 45 #include <sys/proc.h>
46 46 #include <sys/priv.h>
47 47 #include <sys/policy.h>
48 48 #include <sys/ontrap.h>
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49 49 #include <sys/vmsystm.h>
50 50 #include <sys/prsystm.h>
51 51
52 52 #include <vm/as.h>
53 53 #include <vm/seg.h>
54 54 #include <vm/seg_dev.h>
55 55 #include <vm/seg_vn.h>
56 56 #include <vm/seg_spt.h>
57 57 #include <vm/seg_kmem.h>
58 58
59 -extern struct seg_ops segdev_ops; /* needs a header file */
60 -extern struct seg_ops segspt_shmops; /* needs a header file */
59 +extern const struct seg_ops segdev_ops; /* needs a header file */
60 +extern const struct seg_ops segspt_shmops; /* needs a header file */
61 61
62 62 static int
63 63 page_valid(struct seg *seg, caddr_t addr)
64 64 {
65 65 struct segvn_data *svd;
66 66 vnode_t *vp;
67 67 vattr_t vattr;
68 68
69 69 /*
70 70 * Fail if the page doesn't map to a page in the underlying
71 71 * mapped file, if an underlying mapped file exists.
72 72 */
73 73 vattr.va_mask = AT_SIZE;
74 74 if (seg->s_ops == &segvn_ops &&
75 75 segop_getvp(seg, addr, &vp) == 0 &&
76 76 vp != NULL && vp->v_type == VREG &&
77 77 VOP_GETATTR(vp, &vattr, 0, CRED(), NULL) == 0) {
78 78 u_offset_t size = roundup(vattr.va_size, (u_offset_t)PAGESIZE);
79 79 u_offset_t offset = segop_getoffset(seg, addr);
80 80
81 81 if (offset >= size)
82 82 return (0);
83 83 }
84 84
85 85 /*
86 86 * Fail if this is an ISM shared segment and the address is
87 87 * not within the real size of the spt segment that backs it.
88 88 */
89 89 if (seg->s_ops == &segspt_shmops &&
90 90 addr >= seg->s_base + spt_realsize(seg))
91 91 return (0);
92 92
93 93 /*
94 94 * Fail if the segment is mapped from /dev/null.
95 95 * The key is that the mapping comes from segdev and the
96 96 * type is neither MAP_SHARED nor MAP_PRIVATE.
97 97 */
98 98 if (seg->s_ops == &segdev_ops &&
99 99 ((segop_gettype(seg, addr) & (MAP_SHARED | MAP_PRIVATE)) == 0))
100 100 return (0);
101 101
102 102 /*
103 103 * Fail if the page is a MAP_NORESERVE page that has
104 104 * not actually materialized.
105 105 * We cheat by knowing that segvn is the only segment
106 106 * driver that supports MAP_NORESERVE.
107 107 */
108 108 if (seg->s_ops == &segvn_ops &&
109 109 (svd = (struct segvn_data *)seg->s_data) != NULL &&
110 110 (svd->vp == NULL || svd->vp->v_type != VREG) &&
111 111 (svd->flags & MAP_NORESERVE)) {
112 112 /*
113 113 * Guilty knowledge here. We know that
114 114 * segvn_incore returns more than just the
115 115 * low-order bit that indicates the page is
116 116 * actually in memory. If any bits are set,
117 117 * then there is backing store for the page.
118 118 */
119 119 char incore = 0;
120 120 (void) segop_incore(seg, addr, PAGESIZE, &incore);
121 121 if (incore == 0)
122 122 return (0);
123 123 }
124 124 return (1);
125 125 }
126 126
127 127 /*
128 128 * Map address "addr" in address space "as" into a kernel virtual address.
129 129 * The memory is guaranteed to be resident and locked down.
130 130 */
131 131 static caddr_t
132 132 mapin(struct as *as, caddr_t addr, int writing)
133 133 {
134 134 page_t *pp;
135 135 caddr_t kaddr;
136 136 pfn_t pfnum;
137 137
138 138 /*
139 139 * NB: Because of past mistakes, we have bits being returned
140 140 * by getpfnum that are actually the page type bits of the pte.
141 141 * When the object we are trying to map is a memory page with
142 142 * a page structure everything is ok and we can use the optimal
143 143 * method, ppmapin. Otherwise, we have to do something special.
144 144 */
145 145 pfnum = hat_getpfnum(as->a_hat, addr);
146 146 if (pf_is_memory(pfnum)) {
147 147 pp = page_numtopp_nolock(pfnum);
148 148 if (pp != NULL) {
149 149 ASSERT(PAGE_LOCKED(pp));
150 150 kaddr = ppmapin(pp, writing ?
151 151 (PROT_READ | PROT_WRITE) : PROT_READ,
152 152 (caddr_t)-1);
153 153 return (kaddr + ((uintptr_t)addr & PAGEOFFSET));
154 154 }
155 155 }
156 156
157 157 /*
158 158 * Oh well, we didn't have a page struct for the object we were
159 159 * trying to map in; ppmapin doesn't handle devices, but allocating a
160 160 * heap address allows ppmapout to free virutal space when done.
161 161 */
162 162 kaddr = vmem_alloc(heap_arena, PAGESIZE, VM_SLEEP);
163 163
164 164 hat_devload(kas.a_hat, kaddr, PAGESIZE, pfnum,
165 165 writing ? (PROT_READ | PROT_WRITE) : PROT_READ, HAT_LOAD_LOCK);
166 166
167 167 return (kaddr + ((uintptr_t)addr & PAGEOFFSET));
168 168 }
169 169
170 170 /*ARGSUSED*/
171 171 static void
172 172 mapout(struct as *as, caddr_t addr, caddr_t vaddr, int writing)
173 173 {
174 174 vaddr = (caddr_t)(uintptr_t)((uintptr_t)vaddr & PAGEMASK);
175 175 ppmapout(vaddr);
176 176 }
177 177
178 178 /*
179 179 * Perform I/O to a given process. This will return EIO if we detect
180 180 * corrupt memory and ENXIO if there is no such mapped address in the
181 181 * user process's address space.
182 182 */
183 183 static int
184 184 urw(proc_t *p, int writing, void *buf, size_t len, uintptr_t a)
185 185 {
186 186 caddr_t addr = (caddr_t)a;
187 187 caddr_t page;
188 188 caddr_t vaddr;
189 189 struct seg *seg;
190 190 int error = 0;
191 191 int err = 0;
192 192 uint_t prot;
193 193 uint_t prot_rw = writing ? PROT_WRITE : PROT_READ;
194 194 int protchanged;
195 195 on_trap_data_t otd;
196 196 int retrycnt;
197 197 struct as *as = p->p_as;
198 198 enum seg_rw rw;
199 199
200 200 /*
201 201 * Locate segment containing address of interest.
202 202 */
203 203 page = (caddr_t)(uintptr_t)((uintptr_t)addr & PAGEMASK);
204 204 retrycnt = 0;
205 205 AS_LOCK_ENTER(as, &as->a_lock, RW_WRITER);
206 206 retry:
207 207 if ((seg = as_segat(as, page)) == NULL ||
208 208 !page_valid(seg, page)) {
209 209 AS_LOCK_EXIT(as, &as->a_lock);
210 210 return (ENXIO);
211 211 }
212 212 segop_getprot(seg, page, 0, &prot);
213 213
214 214 protchanged = 0;
215 215 if ((prot & prot_rw) == 0) {
216 216 protchanged = 1;
217 217 err = segop_setprot(seg, page, PAGESIZE, prot | prot_rw);
218 218
219 219 if (err == IE_RETRY) {
220 220 protchanged = 0;
221 221 ASSERT(retrycnt == 0);
222 222 retrycnt++;
223 223 goto retry;
224 224 }
225 225
226 226 if (err != 0) {
227 227 AS_LOCK_EXIT(as, &as->a_lock);
228 228 return (ENXIO);
229 229 }
230 230 }
231 231
232 232 /*
233 233 * segvn may do a copy-on-write for F_SOFTLOCK/S_READ case to break
234 234 * sharing to avoid a copy on write of a softlocked page by another
235 235 * thread. But since we locked the address space as a writer no other
236 236 * thread can cause a copy on write. S_READ_NOCOW is passed as the
237 237 * access type to tell segvn that it's ok not to do a copy-on-write
238 238 * for this SOFTLOCK fault.
239 239 */
240 240 if (writing)
241 241 rw = S_WRITE;
242 242 else if (seg->s_ops == &segvn_ops)
243 243 rw = S_READ_NOCOW;
244 244 else
245 245 rw = S_READ;
246 246
247 247 if (segop_fault(as->a_hat, seg, page, PAGESIZE, F_SOFTLOCK, rw)) {
248 248 if (protchanged)
249 249 (void) segop_setprot(seg, page, PAGESIZE, prot);
250 250 AS_LOCK_EXIT(as, &as->a_lock);
251 251 return (ENXIO);
252 252 }
253 253 CPU_STATS_ADD_K(vm, softlock, 1);
254 254
255 255 /*
256 256 * Make sure we're not trying to read or write off the end of the page.
257 257 */
258 258 ASSERT(len <= page + PAGESIZE - addr);
259 259
260 260 /*
261 261 * Map in the locked page, copy to our local buffer,
262 262 * then map the page out and unlock it.
263 263 */
264 264 vaddr = mapin(as, addr, writing);
265 265
266 266 /*
267 267 * Since we are copying memory on behalf of the user process,
268 268 * protect against memory error correction faults.
269 269 */
270 270 if (!on_trap(&otd, OT_DATA_EC)) {
271 271 if (seg->s_ops == &segdev_ops) {
272 272 /*
273 273 * Device memory can behave strangely; invoke
274 274 * a segdev-specific copy operation instead.
275 275 */
276 276 if (writing) {
277 277 if (segdev_copyto(seg, addr, buf, vaddr, len))
278 278 error = ENXIO;
279 279 } else {
280 280 if (segdev_copyfrom(seg, addr, vaddr, buf, len))
281 281 error = ENXIO;
282 282 }
283 283 } else {
284 284 if (writing)
285 285 bcopy(buf, vaddr, len);
286 286 else
287 287 bcopy(vaddr, buf, len);
288 288 }
289 289 } else {
290 290 error = EIO;
291 291 }
292 292 no_trap();
293 293
294 294 /*
295 295 * If we're writing to an executable page, we may need to sychronize
296 296 * the I$ with the modifications we made through the D$.
297 297 */
298 298 if (writing && (prot & PROT_EXEC))
299 299 sync_icache(vaddr, (uint_t)len);
300 300
301 301 mapout(as, addr, vaddr, writing);
302 302
303 303 if (rw == S_READ_NOCOW)
304 304 rw = S_READ;
305 305
306 306 (void) segop_fault(as->a_hat, seg, page, PAGESIZE, F_SOFTUNLOCK, rw);
307 307
308 308 if (protchanged)
309 309 (void) segop_setprot(seg, page, PAGESIZE, prot);
310 310
311 311 AS_LOCK_EXIT(as, &as->a_lock);
312 312
313 313 return (error);
314 314 }
315 315
316 316 int
317 317 uread(proc_t *p, void *buf, size_t len, uintptr_t a)
318 318 {
319 319 return (urw(p, 0, buf, len, a));
320 320 }
321 321
322 322 int
323 323 uwrite(proc_t *p, void *buf, size_t len, uintptr_t a)
324 324 {
325 325 return (urw(p, 1, buf, len, a));
326 326 }
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