1 /*- 2 * Copyright (c) 1988 University of Utah. 3 * Copyright (c) 1982, 1986, 1990 The Regents of the University of California. 4 * 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, and code derived from software contributed to 9 * Berkeley by William Jolitz. 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. All advertising materials mentioning features or use of this software 20 * must display the following acknowledgement: 21 * This product includes software developed by the University of 22 * California, Berkeley and its contributors. 23 * 4. Neither the name of the University nor the names of its contributors 24 * may be used to endorse or promote products derived from this software 25 * without specific prior written permission. 26 * 27 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 28 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 29 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 30 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 31 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 32 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 33 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 34 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 35 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 36 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 37 * SUCH DAMAGE. 38 * 39 * from: Utah $Hdr: mem.c 1.13 89/10/08$ 40 * from: @(#)mem.c 7.2 (Berkeley) 5/9/91 41 * $FreeBSD: src/sys/i386/i386/mem.c,v 1.79.2.9 2003/01/04 22:58:01 njl Exp $ 42 * $DragonFly: src/sys/kern/kern_memio.c,v 1.30 2007/02/25 23:17:12 corecode Exp $ 43 */ 44 45 /* 46 * Memory special file 47 */ 48 49 #include <sys/param.h> 50 #include <sys/systm.h> 51 #include <sys/buf.h> 52 #include <sys/conf.h> 53 #include <sys/fcntl.h> 54 #include <sys/filio.h> 55 #include <sys/ioccom.h> 56 #include <sys/kernel.h> 57 #include <sys/malloc.h> 58 #include <sys/memrange.h> 59 #include <sys/proc.h> 60 #include <sys/random.h> 61 #include <sys/signalvar.h> 62 #include <sys/signal2.h> 63 #include <sys/uio.h> 64 #include <sys/vnode.h> 65 66 #include <vm/vm.h> 67 #include <vm/pmap.h> 68 #include <vm/vm_extern.h> 69 70 71 static d_open_t mmopen; 72 static d_close_t mmclose; 73 static d_read_t mmread; 74 static d_write_t mmwrite; 75 static d_ioctl_t mmioctl; 76 static d_mmap_t memmmap; 77 static d_poll_t mmpoll; 78 79 #define CDEV_MAJOR 2 80 static struct dev_ops mem_ops = { 81 { "mem", CDEV_MAJOR, D_MEM }, 82 .d_open = mmopen, 83 .d_close = mmclose, 84 .d_read = mmread, 85 .d_write = mmwrite, 86 .d_ioctl = mmioctl, 87 .d_poll = mmpoll, 88 .d_mmap = memmmap, 89 }; 90 91 static int rand_bolt; 92 static caddr_t zbuf; 93 94 MALLOC_DEFINE(M_MEMDESC, "memdesc", "memory range descriptors"); 95 static int mem_ioctl (cdev_t, u_long, caddr_t, int, struct ucred *); 96 static int random_ioctl (cdev_t, u_long, caddr_t, int, struct ucred *); 97 98 struct mem_range_softc mem_range_softc; 99 100 101 static int 102 mmopen(struct dev_open_args *ap) 103 { 104 cdev_t dev = ap->a_head.a_dev; 105 int error; 106 107 switch (minor(dev)) { 108 case 0: 109 case 1: 110 if (ap->a_oflags & FWRITE) { 111 if (securelevel > 0 || kernel_mem_readonly) 112 return (EPERM); 113 } 114 error = 0; 115 break; 116 case 14: 117 error = suser_cred(ap->a_cred, 0); 118 if (error != 0) 119 break; 120 if (securelevel > 0 || kernel_mem_readonly) { 121 error = EPERM; 122 break; 123 } 124 error = cpu_set_iopl(); 125 break; 126 default: 127 error = 0; 128 break; 129 } 130 return (error); 131 } 132 133 static int 134 mmclose(struct dev_close_args *ap) 135 { 136 cdev_t dev = ap->a_head.a_dev; 137 int error; 138 139 switch (minor(dev)) { 140 case 14: 141 error = cpu_clr_iopl(); 142 break; 143 default: 144 error = 0; 145 break; 146 } 147 return (error); 148 } 149 150 151 static int 152 mmrw(cdev_t dev, struct uio *uio, int flags) 153 { 154 int o; 155 u_int c, v; 156 u_int poolsize; 157 struct iovec *iov; 158 int error = 0; 159 caddr_t buf = NULL; 160 161 while (uio->uio_resid > 0 && error == 0) { 162 iov = uio->uio_iov; 163 if (iov->iov_len == 0) { 164 uio->uio_iov++; 165 uio->uio_iovcnt--; 166 if (uio->uio_iovcnt < 0) 167 panic("mmrw"); 168 continue; 169 } 170 switch (minor(dev)) { 171 case 0: 172 /* 173 * minor device 0 is physical memory, /dev/mem 174 */ 175 v = uio->uio_offset; 176 v &= ~PAGE_MASK; 177 pmap_kenter((vm_offset_t)ptvmmap, v); 178 o = (int)uio->uio_offset & PAGE_MASK; 179 c = (u_int)(PAGE_SIZE - ((int)iov->iov_base & PAGE_MASK)); 180 c = min(c, (u_int)(PAGE_SIZE - o)); 181 c = min(c, (u_int)iov->iov_len); 182 error = uiomove((caddr_t)&ptvmmap[o], (int)c, uio); 183 pmap_kremove((vm_offset_t)ptvmmap); 184 continue; 185 186 case 1: { 187 /* 188 * minor device 1 is kernel memory, /dev/kmem 189 */ 190 vm_offset_t saddr, eaddr; 191 int prot; 192 193 c = iov->iov_len; 194 195 /* 196 * Make sure that all of the pages are currently 197 * resident so that we don't create any zero-fill 198 * pages. 199 */ 200 saddr = trunc_page(uio->uio_offset); 201 eaddr = round_page(uio->uio_offset + c); 202 if (saddr > eaddr) 203 return EFAULT; 204 205 /* 206 * Make sure the kernel addresses are mapped. 207 * platform_direct_mapped() can be used to bypass 208 * default mapping via the page table (virtual kernels 209 * contain a lot of out-of-band data). 210 */ 211 prot = VM_PROT_READ; 212 if (uio->uio_rw != UIO_READ) 213 prot |= VM_PROT_WRITE; 214 error = kvm_access_check(saddr, eaddr, prot); 215 if (error) 216 return (error); 217 error = uiomove((caddr_t)(vm_offset_t)uio->uio_offset, 218 (int)c, uio); 219 continue; 220 } 221 case 2: 222 /* 223 * minor device 2 is EOF/RATHOLE 224 */ 225 if (uio->uio_rw == UIO_READ) 226 return (0); 227 c = iov->iov_len; 228 break; 229 case 3: 230 /* 231 * minor device 3 (/dev/random) is source of filth 232 * on read, seeder on write 233 */ 234 if (buf == NULL) 235 buf = kmalloc(PAGE_SIZE, M_TEMP, M_WAITOK); 236 c = min(iov->iov_len, PAGE_SIZE); 237 if (uio->uio_rw == UIO_WRITE) { 238 error = uiomove(buf, (int)c, uio); 239 if (error == 0) 240 error = add_buffer_randomness(buf, c); 241 } else { 242 poolsize = read_random(buf, c); 243 if (poolsize == 0) { 244 if (buf) 245 kfree(buf, M_TEMP); 246 if ((flags & IO_NDELAY) != 0) 247 return (EWOULDBLOCK); 248 return (0); 249 } 250 c = min(c, poolsize); 251 error = uiomove(buf, (int)c, uio); 252 } 253 continue; 254 case 4: 255 /* 256 * minor device 4 (/dev/urandom) is source of muck 257 * on read, writes are disallowed. 258 */ 259 c = min(iov->iov_len, PAGE_SIZE); 260 if (uio->uio_rw == UIO_WRITE) { 261 error = EPERM; 262 break; 263 } 264 if (CURSIG(curthread->td_lwp) != 0) { 265 /* 266 * Use tsleep() to get the error code right. 267 * It should return immediately. 268 */ 269 error = tsleep(&rand_bolt, PCATCH, "urand", 1); 270 if (error != 0 && error != EWOULDBLOCK) 271 continue; 272 } 273 if (buf == NULL) 274 buf = kmalloc(PAGE_SIZE, M_TEMP, M_WAITOK); 275 poolsize = read_random_unlimited(buf, c); 276 c = min(c, poolsize); 277 error = uiomove(buf, (int)c, uio); 278 continue; 279 case 12: 280 /* 281 * minor device 12 (/dev/zero) is source of nulls 282 * on read, write are disallowed. 283 */ 284 if (uio->uio_rw == UIO_WRITE) { 285 c = iov->iov_len; 286 break; 287 } 288 if (zbuf == NULL) { 289 zbuf = (caddr_t) 290 kmalloc(PAGE_SIZE, M_TEMP, M_WAITOK); 291 bzero(zbuf, PAGE_SIZE); 292 } 293 c = min(iov->iov_len, PAGE_SIZE); 294 error = uiomove(zbuf, (int)c, uio); 295 continue; 296 default: 297 return (ENODEV); 298 } 299 if (error) 300 break; 301 iov->iov_base += c; 302 iov->iov_len -= c; 303 uio->uio_offset += c; 304 uio->uio_resid -= c; 305 } 306 if (buf) 307 kfree(buf, M_TEMP); 308 return (error); 309 } 310 311 static int 312 mmread(struct dev_read_args *ap) 313 { 314 return(mmrw(ap->a_head.a_dev, ap->a_uio, ap->a_ioflag)); 315 } 316 317 static int 318 mmwrite(struct dev_write_args *ap) 319 { 320 return(mmrw(ap->a_head.a_dev, ap->a_uio, ap->a_ioflag)); 321 } 322 323 324 325 326 327 /*******************************************************\ 328 * allow user processes to MMAP some memory sections * 329 * instead of going through read/write * 330 \*******************************************************/ 331 332 static int 333 memmmap(struct dev_mmap_args *ap) 334 { 335 cdev_t dev = ap->a_head.a_dev; 336 337 switch (minor(dev)) { 338 case 0: 339 /* 340 * minor device 0 is physical memory 341 */ 342 ap->a_result = i386_btop(ap->a_offset); 343 return 0; 344 case 1: 345 /* 346 * minor device 1 is kernel memory 347 */ 348 ap->a_result = i386_btop(vtophys(ap->a_offset)); 349 return 0; 350 351 default: 352 return EINVAL; 353 } 354 } 355 356 static int 357 mmioctl(struct dev_ioctl_args *ap) 358 { 359 cdev_t dev = ap->a_head.a_dev; 360 361 switch (minor(dev)) { 362 case 0: 363 return mem_ioctl(dev, ap->a_cmd, ap->a_data, 364 ap->a_fflag, ap->a_cred); 365 case 3: 366 case 4: 367 return random_ioctl(dev, ap->a_cmd, ap->a_data, 368 ap->a_fflag, ap->a_cred); 369 } 370 return (ENODEV); 371 } 372 373 /* 374 * Operations for changing memory attributes. 375 * 376 * This is basically just an ioctl shim for mem_range_attr_get 377 * and mem_range_attr_set. 378 */ 379 static int 380 mem_ioctl(cdev_t dev, u_long cmd, caddr_t data, int flags, struct ucred *cred) 381 { 382 int nd, error = 0; 383 struct mem_range_op *mo = (struct mem_range_op *)data; 384 struct mem_range_desc *md; 385 386 /* is this for us? */ 387 if ((cmd != MEMRANGE_GET) && 388 (cmd != MEMRANGE_SET)) 389 return (ENOTTY); 390 391 /* any chance we can handle this? */ 392 if (mem_range_softc.mr_op == NULL) 393 return (EOPNOTSUPP); 394 395 /* do we have any descriptors? */ 396 if (mem_range_softc.mr_ndesc == 0) 397 return (ENXIO); 398 399 switch (cmd) { 400 case MEMRANGE_GET: 401 nd = imin(mo->mo_arg[0], mem_range_softc.mr_ndesc); 402 if (nd > 0) { 403 md = (struct mem_range_desc *) 404 kmalloc(nd * sizeof(struct mem_range_desc), 405 M_MEMDESC, M_WAITOK); 406 error = mem_range_attr_get(md, &nd); 407 if (!error) 408 error = copyout(md, mo->mo_desc, 409 nd * sizeof(struct mem_range_desc)); 410 kfree(md, M_MEMDESC); 411 } else { 412 nd = mem_range_softc.mr_ndesc; 413 } 414 mo->mo_arg[0] = nd; 415 break; 416 417 case MEMRANGE_SET: 418 md = (struct mem_range_desc *)kmalloc(sizeof(struct mem_range_desc), 419 M_MEMDESC, M_WAITOK); 420 error = copyin(mo->mo_desc, md, sizeof(struct mem_range_desc)); 421 /* clamp description string */ 422 md->mr_owner[sizeof(md->mr_owner) - 1] = 0; 423 if (error == 0) 424 error = mem_range_attr_set(md, &mo->mo_arg[0]); 425 kfree(md, M_MEMDESC); 426 break; 427 } 428 return (error); 429 } 430 431 /* 432 * Implementation-neutral, kernel-callable functions for manipulating 433 * memory range attributes. 434 */ 435 int 436 mem_range_attr_get(struct mem_range_desc *mrd, int *arg) 437 { 438 /* can we handle this? */ 439 if (mem_range_softc.mr_op == NULL) 440 return (EOPNOTSUPP); 441 442 if (*arg == 0) { 443 *arg = mem_range_softc.mr_ndesc; 444 } else { 445 bcopy(mem_range_softc.mr_desc, mrd, (*arg) * sizeof(struct mem_range_desc)); 446 } 447 return (0); 448 } 449 450 int 451 mem_range_attr_set(struct mem_range_desc *mrd, int *arg) 452 { 453 /* can we handle this? */ 454 if (mem_range_softc.mr_op == NULL) 455 return (EOPNOTSUPP); 456 457 return (mem_range_softc.mr_op->set(&mem_range_softc, mrd, arg)); 458 } 459 460 #ifdef SMP 461 void 462 mem_range_AP_init(void) 463 { 464 if (mem_range_softc.mr_op && mem_range_softc.mr_op->initAP) 465 return (mem_range_softc.mr_op->initAP(&mem_range_softc)); 466 } 467 #endif 468 469 static int 470 random_ioctl(cdev_t dev, u_long cmd, caddr_t data, int flags, struct ucred *cred) 471 { 472 int error; 473 int intr; 474 475 /* 476 * Even inspecting the state is privileged, since it gives a hint 477 * about how easily the randomness might be guessed. 478 */ 479 error = 0; 480 481 switch (cmd) { 482 /* Really handled in upper layer */ 483 case FIOASYNC: 484 break; 485 case MEM_SETIRQ: 486 intr = *(int16_t *)data; 487 if ((error = suser_cred(cred, 0)) != 0) 488 break; 489 if (intr < 0 || intr >= MAX_INTS) 490 return (EINVAL); 491 register_randintr(intr); 492 break; 493 case MEM_CLEARIRQ: 494 intr = *(int16_t *)data; 495 if ((error = suser_cred(cred, 0)) != 0) 496 break; 497 if (intr < 0 || intr >= MAX_INTS) 498 return (EINVAL); 499 unregister_randintr(intr); 500 break; 501 case MEM_RETURNIRQ: 502 error = ENOTSUP; 503 break; 504 case MEM_FINDIRQ: 505 intr = *(int16_t *)data; 506 if ((error = suser_cred(cred, 0)) != 0) 507 break; 508 if (intr < 0 || intr >= MAX_INTS) 509 return (EINVAL); 510 intr = next_registered_randintr(intr); 511 if (intr == MAX_INTS) 512 return (ENOENT); 513 *(u_int16_t *)data = intr; 514 break; 515 default: 516 error = ENOTSUP; 517 break; 518 } 519 return (error); 520 } 521 522 int 523 mmpoll(struct dev_poll_args *ap) 524 { 525 cdev_t dev = ap->a_head.a_dev; 526 int revents; 527 528 switch (minor(dev)) { 529 case 3: /* /dev/random */ 530 revents = random_poll(dev, ap->a_events); 531 break; 532 case 4: /* /dev/urandom */ 533 default: 534 revents = seltrue(dev, ap->a_events); 535 break; 536 } 537 ap->a_events = revents; 538 return (0); 539 } 540 541 int 542 iszerodev(cdev_t dev) 543 { 544 return ((major(dev) == mem_ops.head.maj) 545 && minor(dev) == 12); 546 } 547 548 static void 549 mem_drvinit(void *unused) 550 { 551 552 /* Initialise memory range handling */ 553 if (mem_range_softc.mr_op != NULL) 554 mem_range_softc.mr_op->init(&mem_range_softc); 555 556 dev_ops_add(&mem_ops, 0xf0, 0); 557 make_dev(&mem_ops, 0, UID_ROOT, GID_KMEM, 0640, "mem"); 558 make_dev(&mem_ops, 1, UID_ROOT, GID_KMEM, 0640, "kmem"); 559 make_dev(&mem_ops, 2, UID_ROOT, GID_WHEEL, 0666, "null"); 560 make_dev(&mem_ops, 3, UID_ROOT, GID_WHEEL, 0644, "random"); 561 make_dev(&mem_ops, 4, UID_ROOT, GID_WHEEL, 0644, "urandom"); 562 make_dev(&mem_ops, 12, UID_ROOT, GID_WHEEL, 0666, "zero"); 563 make_dev(&mem_ops, 14, UID_ROOT, GID_WHEEL, 0600, "io"); 564 } 565 566 SYSINIT(memdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,mem_drvinit,NULL) 567 568