sys/dev/md.c

   1 /*      $NetBSD: md.c,v 1.60 2009/07/28 17:55:27 dyoung 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  *
  16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  17  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  18  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  19  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  21  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  22  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  23  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  24  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  25  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  26  */
  27
  28 /*
  29  * This implements a general-purpose memory-disk.
  30  * See md.h for notes on the config types.
  31  *
  32  * Note that this driver provides the same functionality
  33  * as the MFS filesystem hack, but this is better because
  34  * you can use this for any filesystem type you'd like!
  35  *
  36  * Credit for most of the kmem ramdisk code goes to:
  37  *   Leo Weppelman (atari) and Phil Nelson (pc532)
  38  * Credit for the ideas behind the "user space memory" code goes
  39  * to the authors of the MFS implementation.
  40  */
  41
  42 #include <sys/cdefs.h>
  43 __KERNEL_RCSID(0, "$NetBSD: md.c,v 1.60 2009/07/28 17:55:27 dyoung Exp $");
  44
  45 #include "opt_md.h"
  46 #include "opt_tftproot.h"
  47
  48 #include <sys/param.h>
  49 #include <sys/kernel.h>
  50 #include <sys/malloc.h>
  51 #include <sys/systm.h>
  52 #include <sys/buf.h>
  53 #include <sys/bufq.h>
  54 #include <sys/device.h>
  55 #include <sys/disk.h>
  56 #include <sys/stat.h>
  57 #include <sys/proc.h>
  58 #include <sys/conf.h>
  59 #include <sys/disklabel.h>
  60
  61 #include <uvm/uvm_extern.h>
  62
  63 #include <dev/md.h>
  64
  65 /*
  66  * The user-space functionality is included by default.
  67  * Use  `options MEMORY_DISK_SERVER=0' to turn it off.
  68  */
  69 #ifndef MEMORY_DISK_SERVER
  70 #error MEMORY_DISK_SERVER should be defined by opt_md.h
  71 #endif  /* MEMORY_DISK_SERVER */
  72
  73 /*
  74  * We should use the raw partition for ioctl.
  75  */
  76 #define MD_UNIT(unit)   DISKUNIT(unit)
  77
  78 /* autoconfig stuff... */
  79
  80 struct md_softc {
  81         struct disk sc_dkdev;   /* hook for generic disk handling */
  82         struct md_conf sc_md;
  83         struct bufq_state *sc_buflist;
  84 };
  85 /* shorthand for fields in sc_md: */
  86 #define sc_addr sc_md.md_addr
  87 #define sc_size sc_md.md_size
  88 #define sc_type sc_md.md_type
  89
  90 void    mdattach(int);
  91
  92 static void     md_attach(device_t, device_t, void *);
  93 static int      md_detach(device_t, int);
  94
  95 static dev_type_open(mdopen);
  96 static dev_type_close(mdclose);
  97 static dev_type_read(mdread);
  98 static dev_type_write(mdwrite);
  99 static dev_type_ioctl(mdioctl);
 100 static dev_type_strategy(mdstrategy);
 101 static dev_type_size(mdsize);
 102
 103 const struct bdevsw md_bdevsw = {
 104         mdopen, mdclose, mdstrategy, mdioctl, nodump, mdsize, D_DISK
 105 };
 106
 107 const struct cdevsw md_cdevsw = {
 108         mdopen, mdclose, mdread, mdwrite, mdioctl,
 109         nostop, notty, nopoll, nommap, nokqfilter, D_DISK
 110 };
 111
 112 static struct dkdriver mddkdriver = { mdstrategy, NULL };
 113
 114 extern struct cfdriver md_cd;
 115 CFATTACH_DECL3_NEW(md, sizeof(struct md_softc),
 116         0, md_attach, md_detach, NULL, NULL, NULL, DVF_DETACH_SHUTDOWN);
 117
 118 extern size_t md_root_size;
 119
 120 /*
 121  * This is called if we are configured as a pseudo-device
 122  */
 123 void
 124 mdattach(int n)
 125 {
 126         int i;
 127         cfdata_t cf;
 128
 129 #ifdef TFTPROOT
 130         /*
 131          * Attachement of md0 must be done after md_root_setconf(),
 132          * because the RAMdisk is not loaded yet.
 133          */
 134         if (md_root_size == 0)
 135                 return;
 136 #endif
 137         if (config_cfattach_attach("md", &md_ca)) {
 138                 printf("md: cfattach_attach failed\n");
 139                 return;
 140         }
 141
 142         /* XXX:  Are we supposed to provide a default? */
 143         if (n <= 1)
 144                 n = 1;
 145
 146         /* Attach as if by autoconfig. */
 147         for (i = 0; i < n; i++) {
 148                 cf = malloc(sizeof(*cf), M_DEVBUF, M_WAITOK);
 149                 cf->cf_name = "md";
 150                 cf->cf_atname = "md";
 151                 cf->cf_unit = i;
 152                 cf->cf_fstate = FSTATE_NOTFOUND;
 153                 (void)config_attach_pseudo(cf);
 154         }
 155 }
 156
 157 static void
 158 md_attach(device_t parent, device_t self, void *aux)
 159 {
 160         struct md_softc *sc = device_private(self);
 161
 162         bufq_alloc(&sc->sc_buflist, "fcfs", 0);
 163
 164         /* XXX - Could accept aux info here to set the config. */
 165 #ifdef  MEMORY_DISK_HOOKS
 166         /*
 167          * This external function might setup a pre-loaded disk.
 168          * All it would need to do is setup the md_conf struct.
 169          * See sys/dev/md_root.c for an example.
 170          */
 171         md_attach_hook(device_unit(self), &sc->sc_md);
 172 #endif
 173
 174         /*
 175          * Initialize and attach the disk structure.
 176          */
 177         disk_init(&sc->sc_dkdev, device_xname(self), &mddkdriver);
 178         disk_attach(&sc->sc_dkdev);
 179
 180         if (!pmf_device_register(self, NULL, NULL))
 181                 aprint_error_dev(self, "couldn't establish power handler\n");
 182 }
 183
 184 static int
 185 md_detach(device_t self, int flags)
 186 {
 187         struct md_softc *sc = device_private(self);
 188         int rc;
 189
 190         rc = 0;
 191         mutex_enter(&sc->sc_dkdev.dk_openlock);
 192         if (sc->sc_dkdev.dk_openmask == 0)
 193                 ;       /* nothing to do */
 194         else if ((flags & DETACH_FORCE) == 0)
 195                 rc = EBUSY;
 196         mutex_exit(&sc->sc_dkdev.dk_openlock);
 197
 198         if (rc != 0)
 199                 return rc;
 200
 201         pmf_device_deregister(self);
 202         disk_detach(&sc->sc_dkdev);
 203         disk_destroy(&sc->sc_dkdev);
 204         bufq_free(sc->sc_buflist);
 205         return 0;
 206 }
 207
 208 /*
 209  * operational routines:
 210  * open, close, read, write, strategy,
 211  * ioctl, dump, size
 212  */
 213
 214 #if MEMORY_DISK_SERVER
 215 static int      md_server_loop(struct md_softc *sc);
 216 static int      md_ioctl_server(struct md_softc *sc, struct md_conf *umd,
 217                     struct lwp *l);
 218 #endif  /* MEMORY_DISK_SERVER */
 219 static int      md_ioctl_kalloc(struct md_softc *sc, struct md_conf *umd,
 220                     struct lwp *l);
 221
 222 static int
 223 mdsize(dev_t dev)
 224 {
 225         struct md_softc *sc;
 226
 227         sc = device_lookup_private(&md_cd, MD_UNIT(dev));
 228         if (sc == NULL)
 229                 return 0;
 230
 231         if (sc->sc_type == MD_UNCONFIGURED)
 232                 return 0;
 233
 234         return (sc->sc_size >> DEV_BSHIFT);
 235 }
 236
 237 static int
 238 mdopen(dev_t dev, int flag, int fmt, struct lwp *l)
 239 {
 240         int unit;
 241         int part = DISKPART(dev);
 242         int pmask = 1 << part;
 243         struct md_softc *sc;
 244         struct disk *dk;
 245
 246         unit = MD_UNIT(dev);
 247         sc = device_lookup_private(&md_cd, unit);
 248         if (sc == NULL)
 249                 return ENXIO;
 250
 251         dk = &sc->sc_dkdev;
 252
 253         /*
 254          * The raw partition is used for ioctl to configure.
 255          */
 256         if (part == RAW_PART)
 257                 goto ok;
 258
 259 #ifdef  MEMORY_DISK_HOOKS
 260         /* Call the open hook to allow loading the device. */
 261         md_open_hook(unit, &sc->sc_md);
 262 #endif
 263
 264         /*
 265          * This is a normal, "slave" device, so
 266          * enforce initialized.
 267          */
 268         if (sc->sc_type == MD_UNCONFIGURED)
 269                 return ENXIO;
 270
 271 ok:
 272         /* XXX duplicates code in dk_open().  Call dk_open(), instead? */
 273         mutex_enter(&dk->dk_openlock);
 274         /* Mark our unit as open. */
 275         switch (fmt) {
 276         case S_IFCHR:
 277                 dk->dk_copenmask |= pmask;
 278                 break;
 279         case S_IFBLK:
 280                 dk->dk_bopenmask |= pmask;
 281                 break;
 282         }
 283
 284         dk->dk_openmask = dk->dk_copenmask | dk->dk_bopenmask;
 285
 286         mutex_exit(&dk->dk_openlock);
 287         return 0;
 288 }
 289
 290 static int
 291 mdclose(dev_t dev, int flag, int fmt, struct lwp *l)
 292 {
 293         int part = DISKPART(dev);
 294         int pmask = 1 << part;
 295         struct md_softc *sc;
 296         struct disk *dk;
 297
 298         sc = device_lookup_private(&md_cd, MD_UNIT(dev));
 299         if (sc == NULL)
 300                 return ENXIO;
 301
 302         dk = &sc->sc_dkdev;
 303
 304         mutex_enter(&dk->dk_openlock);
 305
 306         switch (fmt) {
 307         case S_IFCHR:
 308                 dk->dk_copenmask &= ~pmask;
 309                 break;
 310         case S_IFBLK:
 311                 dk->dk_bopenmask &= ~pmask;
 312                 break;
 313         }
 314         dk->dk_openmask = dk->dk_copenmask | dk->dk_bopenmask;
 315
 316         mutex_exit(&dk->dk_openlock);
 317         return 0;
 318 }
 319
 320 static int
 321 mdread(dev_t dev, struct uio *uio, int flags)
 322 {
 323         struct md_softc *sc;
 324
 325         sc = device_lookup_private(&md_cd, MD_UNIT(dev));
 326
 327         if (sc->sc_type == MD_UNCONFIGURED)
 328                 return ENXIO;
 329
 330         return (physio(mdstrategy, NULL, dev, B_READ, minphys, uio));
 331 }
 332
 333 static int
 334 mdwrite(dev_t dev, struct uio *uio, int flags)
 335 {
 336         struct md_softc *sc;
 337
 338         sc = device_lookup_private(&md_cd, MD_UNIT(dev));
 339
 340         if (sc->sc_type == MD_UNCONFIGURED)
 341                 return ENXIO;
 342
 343         return (physio(mdstrategy, NULL, dev, B_WRITE, minphys, uio));
 344 }
 345
 346 /*
 347  * Handle I/O requests, either directly, or
 348  * by passing them to the server process.
 349  */
 350 static void
 351 mdstrategy(struct buf *bp)
 352 {
 353         struct md_softc *sc;
 354         void *  addr;
 355         size_t off, xfer;
 356
 357         sc = device_lookup_private(&md_cd, MD_UNIT(bp->b_dev));
 358
 359         if (sc->sc_type == MD_UNCONFIGURED) {
 360                 bp->b_error = ENXIO;
 361                 goto done;
 362         }
 363
 364         switch (sc->sc_type) {
 365 #if MEMORY_DISK_SERVER
 366         case MD_UMEM_SERVER:
 367                 /* Just add this job to the server's queue. */
 368                 bufq_put(sc->sc_buflist, bp);
 369                 wakeup((void *)sc);
 370                 /* see md_server_loop() */
 371                 /* no biodone in this case */
 372                 return;
 373 #endif  /* MEMORY_DISK_SERVER */
 374
 375         case MD_KMEM_FIXED:
 376         case MD_KMEM_ALLOCATED:
 377                 /* These are in kernel space.  Access directly. */
 378                 bp->b_resid = bp->b_bcount;
 379                 off = (bp->b_blkno << DEV_BSHIFT);
 380                 if (off >= sc->sc_size) {
 381                         if (bp->b_flags & B_READ)
 382                                 break;  /* EOF */
 383                         goto set_eio;
 384                 }
 385                 xfer = bp->b_resid;
 386                 if (xfer > (sc->sc_size - off))
 387                         xfer = (sc->sc_size - off);
 388                 addr = (char *)sc->sc_addr + off;
 389                 if (bp->b_flags & B_READ)
 390                         memcpy(bp->b_data, addr, xfer);
 391                 else
 392                         memcpy(addr, bp->b_data, xfer);
 393                 bp->b_resid -= xfer;
 394                 break;
 395
 396         default:
 397                 bp->b_resid = bp->b_bcount;
 398         set_eio:
 399                 bp->b_error = EIO;
 400                 break;
 401         }
 402  done:
 403         biodone(bp);
 404 }
 405
 406 static int
 407 mdioctl(dev_t dev, u_long cmd, void *data, int flag, struct lwp *l)
 408 {
 409         struct md_softc *sc;
 410         struct md_conf *umd;
 411
 412         sc = device_lookup_private(&md_cd, MD_UNIT(dev));
 413
 414         /* If this is not the raw partition, punt! */
 415         if (DISKPART(dev) != RAW_PART)
 416                 return ENOTTY;
 417
 418         umd = (struct md_conf *)data;
 419         switch (cmd) {
 420         case MD_GETCONF:
 421                 *umd = sc->sc_md;
 422                 return 0;
 423
 424         case MD_SETCONF:
 425                 /* Can only set it once. */
 426                 if (sc->sc_type != MD_UNCONFIGURED)
 427                         break;
 428                 switch (umd->md_type) {
 429                 case MD_KMEM_ALLOCATED:
 430                         return md_ioctl_kalloc(sc, umd, l);
 431 #if MEMORY_DISK_SERVER
 432                 case MD_UMEM_SERVER:
 433                         return md_ioctl_server(sc, umd, l);
 434 #endif  /* MEMORY_DISK_SERVER */
 435                 default:
 436                         break;
 437                 }
 438                 break;
 439         }
 440         return EINVAL;
 441 }
 442
 443 /*
 444  * Handle ioctl MD_SETCONF for (sc_type == MD_KMEM_ALLOCATED)
 445  * Just allocate some kernel memory and return.
 446  */
 447 static int
 448 md_ioctl_kalloc(struct md_softc *sc, struct md_conf *umd,
 449     struct lwp *l)
 450 {
 451         vaddr_t addr;
 452         vsize_t size;
 453
 454         /* Sanity check the size. */
 455         size = umd->md_size;
 456         addr = uvm_km_alloc(kernel_map, size, 0, UVM_KMF_WIRED|UVM_KMF_ZERO);
 457         if (!addr)
 458                 return ENOMEM;
 459
 460         /* This unit is now configured. */
 461         sc->sc_addr = (void *)addr;     /* kernel space */
 462         sc->sc_size = (size_t)size;
 463         sc->sc_type = MD_KMEM_ALLOCATED;
 464         return 0;
 465 }
 466
 467 #if MEMORY_DISK_SERVER
 468
 469 /*
 470  * Handle ioctl MD_SETCONF for (sc_type == MD_UMEM_SERVER)
 471  * Set config, then become the I/O server for this unit.
 472  */
 473 static int
 474 md_ioctl_server(struct md_softc *sc, struct md_conf *umd,
 475     struct lwp *l)
 476 {
 477         vaddr_t end;
 478         int error;
 479
 480         /* Sanity check addr, size. */
 481         end = (vaddr_t) ((char *)umd->md_addr + umd->md_size);
 482
 483         if ((end >= VM_MAXUSER_ADDRESS) ||
 484                 (end < ((vaddr_t) umd->md_addr)) )
 485                 return EINVAL;
 486
 487         /* This unit is now configured. */
 488         sc->sc_addr = umd->md_addr;     /* user space */
 489         sc->sc_size = umd->md_size;
 490         sc->sc_type = MD_UMEM_SERVER;
 491
 492         /* Become the server daemon */
 493         error = md_server_loop(sc);
 494
 495         /* This server is now going away! */
 496         sc->sc_type = MD_UNCONFIGURED;
 497         sc->sc_addr = 0;
 498         sc->sc_size = 0;
 499
 500         return (error);
 501 }
 502
 503 static int md_sleep_pri = PWAIT | PCATCH;
 504
 505 static int
 506 md_server_loop(struct md_softc *sc)
 507 {
 508         struct buf *bp;
 509         void *addr;     /* user space address */
 510         size_t off;     /* offset into "device" */
 511         size_t xfer;    /* amount to transfer */
 512         int error;
 513
 514         for (;;) {
 515                 /* Wait for some work to arrive. */
 516                 while ((bp = bufq_get(sc->sc_buflist)) == NULL) {
 517                         error = tsleep((void *)sc, md_sleep_pri, "md_idle", 0);
 518                         if (error)
 519                                 return error;
 520                 }
 521
 522                 /* Do the transfer to/from user space. */
 523                 error = 0;
 524                 bp->b_resid = bp->b_bcount;
 525                 off = (bp->b_blkno << DEV_BSHIFT);
 526                 if (off >= sc->sc_size) {
 527                         if (bp->b_flags & B_READ)
 528                                 goto done;      /* EOF (not an error) */
 529                         error = EIO;
 530                         goto done;
 531                 }
 532                 xfer = bp->b_resid;
 533                 if (xfer > (sc->sc_size - off))
 534                         xfer = (sc->sc_size - off);
 535                 addr = (char *)sc->sc_addr + off;
 536                 if (bp->b_flags & B_READ)
 537                         error = copyin(addr, bp->b_data, xfer);
 538                 else
 539                         error = copyout(bp->b_data, addr, xfer);
 540                 if (!error)
 541                         bp->b_resid -= xfer;
 542
 543         done:
 544                 if (error) {
 545                         bp->b_error = error;
 546                 }
 547                 biodone(bp);
 548         }
 549 }
 550 #endif  /* MEMORY_DISK_SERVER */