md.c revision 1.16
1 /* $NetBSD: md.c,v 1.16 1998/02/10 14:09:18 mrg Exp $ */ 2 3 /* 4 * Copyright (c) 1995 Gordon W. Ross, Leo Weppelman. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. The name of the author may not be used to endorse or promote products 16 * derived from this software without specific prior written permission. 17 * 4. All advertising materials mentioning features or use of this software 18 * must display the following acknowledgement: 19 * This product includes software developed by 20 * Gordon W. Ross and Leo Weppelman. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 23 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 24 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 25 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 26 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 27 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 28 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 29 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 30 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 31 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 32 */ 33 34 /* 35 * This implements a general-purpose memory-disk. 36 * See md.h for notes on the config types. 37 * 38 * Note that this driver provides the same functionality 39 * as the MFS filesystem hack, but this is better because 40 * you can use this for any filesystem type you'd like! 41 * 42 * Credit for most of the kmem ramdisk code goes to: 43 * Leo Weppelman (atari) and Phil Nelson (pc532) 44 * Credit for the ideas behind the "user space memory" code goes 45 * to the authors of the MFS implementation. 46 */ 47 48 #include "opt_uvm.h" 49 50 #include <sys/param.h> 51 #include <sys/kernel.h> 52 #include <sys/malloc.h> 53 #include <sys/systm.h> 54 #include <sys/buf.h> 55 #include <sys/device.h> 56 #include <sys/disk.h> 57 #include <sys/proc.h> 58 #include <sys/conf.h> 59 #include <sys/disklabel.h> 60 61 #include <vm/vm.h> 62 #include <vm/vm_kern.h> 63 #include <vm/vm_extern.h> 64 65 #include <dev/md.h> 66 67 /* 68 * By default, include the user-space functionality. 69 * Use `options MEMORY_DISK_SERVER=0' to turn it off. 70 */ 71 #ifndef MEMORY_DISK_SERVER 72 #define MEMORY_DISK_SERVER 1 73 #endif 74 75 /* 76 * XXX: the "control" unit is (base unit + 16). 77 * We should just use the cdev as the "control", but 78 * that interferes with the security stuff preventing 79 * simulatneous use of raw and block devices. 80 * 81 * XXX Assumption: 16 memory-disks are enough! 82 */ 83 #define MD_MAX_UNITS 0x10 84 #define MD_IS_CTRL(unit) (unit & 0x10) 85 #define MD_UNIT(unit) (unit & 0xF) 86 87 /* autoconfig stuff... */ 88 89 struct md_softc { 90 struct device sc_dev; /* REQUIRED first entry */ 91 struct disk sc_dkdev; /* hook for generic disk handling */ 92 struct md_conf sc_md; 93 struct buf *sc_buflist; 94 int sc_flags; 95 }; 96 /* shorthand for fields in sc_md: */ 97 #define sc_addr sc_md.md_addr 98 #define sc_size sc_md.md_size 99 #define sc_type sc_md.md_type 100 /* flags */ 101 #define MD_ISOPEN 0x01 102 #define MD_SERVED 0x02 103 104 void mdattach __P((int)); 105 static void md_attach __P((struct device *, struct device *, void *)); 106 107 /* 108 * Some ports (like i386) use a swapgeneric that wants to 109 * snoop around in this md_cd structure. It is preserved 110 * (for now) to remain compatible with such practice. 111 * XXX - that practice is questionable... 112 */ 113 struct cfdriver md_cd = { 114 NULL, "md", DV_DULL, NULL, 0 115 }; 116 117 void mdstrategy __P((struct buf *bp)); 118 struct dkdriver mddkdriver = { mdstrategy }; 119 120 static int ramdisk_ndevs; 121 static void *ramdisk_devs[MD_MAX_UNITS]; 122 123 /* 124 * This is called if we are configured as a pseudo-device 125 */ 126 void 127 mdattach(n) 128 int n; 129 { 130 struct md_softc *sc; 131 int i; 132 133 #ifdef DIAGNOSTIC 134 if (ramdisk_ndevs) { 135 printf("ramdisk: multiple attach calls?\n"); 136 return; 137 } 138 #endif 139 140 /* XXX: Are we supposed to provide a default? */ 141 if (n <= 1) 142 n = 1; 143 if (n > MD_MAX_UNITS) 144 n = MD_MAX_UNITS; 145 ramdisk_ndevs = n; 146 147 /* XXX: Fake-up md_cd (see above) */ 148 md_cd.cd_ndevs = ramdisk_ndevs; 149 md_cd.cd_devs = ramdisk_devs; 150 151 /* Attach as if by autoconfig. */ 152 for (i = 0; i < n; i++) { 153 154 sc = malloc(sizeof(*sc), M_DEVBUF, M_NOWAIT); 155 if (!sc) { 156 printf("ramdisk: malloc for attach failed!\n"); 157 return; 158 } 159 bzero((caddr_t)sc, sizeof(*sc)); 160 ramdisk_devs[i] = sc; 161 sc->sc_dev.dv_unit = i; 162 sprintf(sc->sc_dev.dv_xname, "md%d", i); 163 md_attach(NULL, &sc->sc_dev, NULL); 164 } 165 } 166 167 static void 168 md_attach(parent, self, aux) 169 struct device *parent, *self; 170 void *aux; 171 { 172 struct md_softc *sc = (struct md_softc *)self; 173 174 /* XXX - Could accept aux info here to set the config. */ 175 #ifdef MEMORY_DISK_HOOKS 176 /* 177 * This external function might setup a pre-loaded disk. 178 * All it would need to do is setup the md_conf struct. 179 * See sys/arch/sun3/dev/md_root.c for an example. 180 */ 181 md_attach_hook(sc->sc_dev.dv_unit, &sc->sc_md); 182 #endif 183 184 /* 185 * Initialize and attach the disk structure. 186 */ 187 sc->sc_dkdev.dk_driver = &mddkdriver; 188 sc->sc_dkdev.dk_name = sc->sc_dev.dv_xname; 189 disk_attach(&sc->sc_dkdev); 190 } 191 192 /* 193 * operational routines: 194 * open, close, read, write, strategy, 195 * ioctl, dump, size 196 */ 197 198 #if MEMORY_DISK_SERVER 199 static int md_server_loop __P((struct md_softc *sc)); 200 static int md_ioctl_server __P((struct md_softc *sc, 201 struct md_conf *umd, struct proc *proc)); 202 #endif 203 static int md_ioctl_kalloc __P((struct md_softc *sc, 204 struct md_conf *umd, struct proc *proc)); 205 206 dev_type_open(mdopen); 207 dev_type_close(mdclose); 208 dev_type_read(mdread); 209 dev_type_write(mdwrite); 210 dev_type_ioctl(mdioctl); 211 dev_type_size(mdsize); 212 dev_type_dump(mddump); 213 214 int mddump(dev, blkno, va, size) 215 dev_t dev; 216 daddr_t blkno; 217 caddr_t va; 218 size_t size; 219 { 220 return ENODEV; 221 } 222 223 int mdsize(dev_t dev) 224 { 225 int unit; 226 struct md_softc *sc; 227 228 /* Disallow control units. */ 229 unit = DISKUNIT(dev); 230 if (unit >= ramdisk_ndevs) 231 return 0; 232 sc = ramdisk_devs[unit]; 233 if (sc == NULL) 234 return 0; 235 236 if (sc->sc_type == MD_UNCONFIGURED) 237 return 0; 238 239 return (sc->sc_size >> DEV_BSHIFT); 240 } 241 242 int 243 mdopen(dev, flag, fmt, proc) 244 dev_t dev; 245 int flag, fmt; 246 struct proc *proc; 247 { 248 int md, unit; 249 struct md_softc *sc; 250 251 md = DISKUNIT(dev); 252 unit = MD_UNIT(md); 253 if (unit >= ramdisk_ndevs) 254 return ENXIO; 255 sc = ramdisk_devs[unit]; 256 if (sc == NULL) 257 return ENXIO; 258 259 /* 260 * The control device is not exclusive, and can 261 * open uninitialized units (so you can setconf). 262 */ 263 if (MD_IS_CTRL(md)) 264 return 0; 265 266 #ifdef MEMORY_DISK_HOOKS 267 /* Call the open hook to allow loading the device. */ 268 md_open_hook(unit, &sc->sc_md); 269 #endif 270 271 /* 272 * This is a normal, "slave" device, so 273 * enforce initialized, exclusive open. 274 */ 275 if (sc->sc_type == MD_UNCONFIGURED) 276 return ENXIO; 277 if (sc->sc_flags & MD_ISOPEN) 278 return EBUSY; 279 280 return 0; 281 } 282 283 int 284 mdclose(dev, flag, fmt, proc) 285 dev_t dev; 286 int flag, fmt; 287 struct proc *proc; 288 { 289 int md, unit; 290 struct md_softc *sc; 291 292 md = DISKUNIT(dev); 293 unit = MD_UNIT(md); 294 sc = ramdisk_devs[unit]; 295 296 if (MD_IS_CTRL(md)) 297 return 0; 298 299 /* Normal device. */ 300 sc->sc_flags = 0; 301 302 return 0; 303 } 304 305 int 306 mdread(dev, uio, flags) 307 dev_t dev; 308 struct uio *uio; 309 int flags; 310 { 311 return (physio(mdstrategy, NULL, dev, B_READ, minphys, uio)); 312 } 313 314 int 315 mdwrite(dev, uio, flags) 316 dev_t dev; 317 struct uio *uio; 318 int flags; 319 { 320 return (physio(mdstrategy, NULL, dev, B_WRITE, minphys, uio)); 321 } 322 323 /* 324 * Handle I/O requests, either directly, or 325 * by passing them to the server process. 326 */ 327 void 328 mdstrategy(bp) 329 struct buf *bp; 330 { 331 int md, unit; 332 struct md_softc *sc; 333 caddr_t addr; 334 size_t off, xfer; 335 336 md = DISKUNIT(bp->b_dev); 337 unit = MD_UNIT(md); 338 sc = ramdisk_devs[unit]; 339 340 switch (sc->sc_type) { 341 #if MEMORY_DISK_SERVER 342 case MD_UMEM_SERVER: 343 /* Just add this job to the server's queue. */ 344 bp->b_actf = sc->sc_buflist; 345 sc->sc_buflist = bp; 346 if (bp->b_actf == NULL) { 347 /* server queue was empty. */ 348 wakeup((caddr_t)sc); 349 /* see md_server_loop() */ 350 } 351 /* no biodone in this case */ 352 return; 353 #endif /* MEMORY_DISK_SERVER */ 354 355 case MD_KMEM_FIXED: 356 case MD_KMEM_ALLOCATED: 357 /* These are in kernel space. Access directly. */ 358 bp->b_resid = bp->b_bcount; 359 off = (bp->b_blkno << DEV_BSHIFT); 360 if (off >= sc->sc_size) { 361 if (bp->b_flags & B_READ) 362 break; /* EOF */ 363 goto set_eio; 364 } 365 xfer = bp->b_resid; 366 if (xfer > (sc->sc_size - off)) 367 xfer = (sc->sc_size - off); 368 addr = sc->sc_addr + off; 369 if (bp->b_flags & B_READ) 370 bcopy(addr, bp->b_data, xfer); 371 else 372 bcopy(bp->b_data, addr, xfer); 373 bp->b_resid -= xfer; 374 break; 375 376 default: 377 bp->b_resid = bp->b_bcount; 378 set_eio: 379 bp->b_error = EIO; 380 bp->b_flags |= B_ERROR; 381 break; 382 } 383 biodone(bp); 384 } 385 386 int 387 mdioctl(dev, cmd, data, flag, proc) 388 dev_t dev; 389 u_long cmd; 390 int flag; 391 caddr_t data; 392 struct proc *proc; 393 { 394 int md, unit; 395 struct md_softc *sc; 396 struct md_conf *umd; 397 398 md = DISKUNIT(dev); 399 unit = MD_UNIT(md); 400 sc = ramdisk_devs[unit]; 401 402 /* If this is not the control device, punt! */ 403 if (MD_IS_CTRL(md) == 0) 404 return ENOTTY; 405 406 umd = (struct md_conf *)data; 407 switch (cmd) { 408 case MD_GETCONF: 409 *umd = sc->sc_md; 410 return 0; 411 412 case MD_SETCONF: 413 /* Can only set it once. */ 414 if (sc->sc_type != MD_UNCONFIGURED) 415 break; 416 switch (umd->md_type) { 417 case MD_KMEM_ALLOCATED: 418 return md_ioctl_kalloc(sc, umd, proc); 419 #if MEMORY_DISK_SERVER 420 case MD_UMEM_SERVER: 421 return md_ioctl_server(sc, umd, proc); 422 #endif 423 default: 424 break; 425 } 426 break; 427 } 428 return EINVAL; 429 } 430 431 /* 432 * Handle ioctl MD_SETCONF for (sc_type == MD_KMEM_ALLOCATED) 433 * Just allocate some kernel memory and return. 434 */ 435 static int 436 md_ioctl_kalloc(sc, umd, proc) 437 struct md_softc *sc; 438 struct md_conf *umd; 439 struct proc *proc; 440 { 441 vm_offset_t addr; 442 vm_size_t size; 443 444 /* Sanity check the size. */ 445 size = umd->md_size; 446 #if defined(UVM) 447 addr = uvm_km_zalloc(kernel_map, size); 448 #else 449 addr = kmem_alloc(kernel_map, size); 450 #endif 451 if (!addr) 452 return ENOMEM; 453 454 /* This unit is now configured. */ 455 sc->sc_addr = (caddr_t)addr; /* kernel space */ 456 sc->sc_size = (size_t)size; 457 sc->sc_type = MD_KMEM_ALLOCATED; 458 return 0; 459 } 460 461 #if MEMORY_DISK_SERVER 462 463 /* 464 * Handle ioctl MD_SETCONF for (sc_type == MD_UMEM_SERVER) 465 * Set config, then become the I/O server for this unit. 466 */ 467 static int 468 md_ioctl_server(sc, umd, proc) 469 struct md_softc *sc; 470 struct md_conf *umd; 471 struct proc *proc; 472 { 473 vm_offset_t end; 474 int error; 475 476 /* Sanity check addr, size. */ 477 end = (vm_offset_t) (umd->md_addr + umd->md_size); 478 479 if ((end >= VM_MAXUSER_ADDRESS) || 480 (end < ((vm_offset_t) umd->md_addr)) ) 481 return EINVAL; 482 483 /* This unit is now configured. */ 484 sc->sc_addr = umd->md_addr; /* user space */ 485 sc->sc_size = umd->md_size; 486 sc->sc_type = MD_UMEM_SERVER; 487 488 /* Become the server daemon */ 489 error = md_server_loop(sc); 490 491 /* This server is now going away! */ 492 sc->sc_type = MD_UNCONFIGURED; 493 sc->sc_addr = 0; 494 sc->sc_size = 0; 495 496 return (error); 497 } 498 499 int md_sleep_pri = PWAIT | PCATCH; 500 501 static int 502 md_server_loop(sc) 503 struct md_softc *sc; 504 { 505 struct buf *bp; 506 caddr_t addr; /* user space address */ 507 size_t off; /* offset into "device" */ 508 size_t xfer; /* amount to transfer */ 509 int error; 510 511 for (;;) { 512 /* Wait for some work to arrive. */ 513 while (sc->sc_buflist == NULL) { 514 error = tsleep((caddr_t)sc, md_sleep_pri, "md_idle", 0); 515 if (error) 516 return error; 517 } 518 519 /* Unlink buf from head of list. */ 520 bp = sc->sc_buflist; 521 sc->sc_buflist = bp->b_actf; 522 bp->b_actf = NULL; 523 524 /* Do the transfer to/from user space. */ 525 error = 0; 526 bp->b_resid = bp->b_bcount; 527 off = (bp->b_blkno << DEV_BSHIFT); 528 if (off >= sc->sc_size) { 529 if (bp->b_flags & B_READ) 530 goto done; /* EOF (not an error) */ 531 error = EIO; 532 goto done; 533 } 534 xfer = bp->b_resid; 535 if (xfer > (sc->sc_size - off)) 536 xfer = (sc->sc_size - off); 537 addr = sc->sc_addr + off; 538 if (bp->b_flags & B_READ) 539 error = copyin(addr, bp->b_data, xfer); 540 else 541 error = copyout(bp->b_data, addr, xfer); 542 if (!error) 543 bp->b_resid -= xfer; 544 545 done: 546 if (error) { 547 bp->b_error = error; 548 bp->b_flags |= B_ERROR; 549 } 550 biodone(bp); 551 } 552 } 553 #endif /* MEMORY_DISK_SERVER */ 554
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