The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]

FreeBSD/Linux Kernel Cross Reference
sys/kern/subr_firmware.c

Version: -  FREEBSD  -  FREEBSD-13-STABLE  -  FREEBSD-13-0  -  FREEBSD-12-STABLE  -  FREEBSD-12-0  -  FREEBSD-11-STABLE  -  FREEBSD-11-0  -  FREEBSD-10-STABLE  -  FREEBSD-10-0  -  FREEBSD-9-STABLE  -  FREEBSD-9-0  -  FREEBSD-8-STABLE  -  FREEBSD-8-0  -  FREEBSD-7-STABLE  -  FREEBSD-7-0  -  FREEBSD-6-STABLE  -  FREEBSD-6-0  -  FREEBSD-5-STABLE  -  FREEBSD-5-0  -  FREEBSD-4-STABLE  -  FREEBSD-3-STABLE  -  FREEBSD22  -  l41  -  OPENBSD  -  linux-2.6  -  MK84  -  PLAN9  -  xnu-8792 
SearchContext: -  none  -  3  -  10 

    1 /*-
    2  * Copyright (c) 2005, Sam Leffler <sam@errno.com>
    3  * All rights reserved.
    4  *
    5  * Redistribution and use in source and binary forms, with or without
    6  * modification, are permitted provided that the following conditions
    7  * are met:
    8  * 1. Redistributions of source code must retain the above copyright
    9  *    notice unmodified, this list of conditions, and the following
   10  *    disclaimer.
   11  * 2. Redistributions in binary form must reproduce the above copyright
   12  *    notice, this list of conditions and the following disclaimer in the
   13  *    documentation and/or other materials provided with the distribution.
   14  *
   15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
   16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
   18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
   19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
   20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
   24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   25  */
   26 
   27 #include <sys/cdefs.h>
   28 __FBSDID("$FreeBSD$");
   29 
   30 #include <sys/param.h>
   31 #include <sys/kernel.h>
   32 #include <sys/malloc.h>
   33 #include <sys/queue.h>
   34 #include <sys/taskqueue.h>
   35 #include <sys/systm.h>
   36 #include <sys/lock.h>
   37 #include <sys/mutex.h>
   38 #include <sys/errno.h>
   39 #include <sys/linker.h>
   40 #include <sys/firmware.h>
   41 #include <sys/priv.h>
   42 #include <sys/proc.h>
   43 #include <sys/module.h>
   44 
   45 /*
   46  * Loadable firmware support. See sys/sys/firmware.h and firmware(9)
   47  * form more details on the subsystem.
   48  *
   49  * 'struct firmware' is the user-visible part of the firmware table.
   50  * Additional internal information is stored in a 'struct priv_fw'
   51  * (currently a static array). A slot is in use if FW_INUSE is true:
   52  */
   53 
   54 #define FW_INUSE(p)     ((p)->file != NULL || (p)->fw.name != NULL)
   55 
   56 /*
   57  * fw.name != NULL when an image is registered; file != NULL for
   58  * autoloaded images whose handling has not been completed.
   59  *
   60  * The state of a slot evolves as follows:
   61  *      firmware_register       -->  fw.name = image_name
   62  *      (autoloaded image)      -->  file = module reference
   63  *      firmware_unregister     -->  fw.name = NULL
   64  *      (unloadentry complete)  -->  file = NULL
   65  *
   66  * In order for the above to work, the 'file' field must remain
   67  * unchanged in firmware_unregister().
   68  *
   69  * Images residing in the same module are linked to each other
   70  * through the 'parent' argument of firmware_register().
   71  * One image (typically, one with the same name as the module to let
   72  * the autoloading mechanism work) is considered the parent image for
   73  * all other images in the same module. Children affect the refcount
   74  * on the parent image preventing improper unloading of the image itself.
   75  */
   76 
   77 struct priv_fw {
   78         int             refcnt;         /* reference count */
   79 
   80         /*
   81          * parent entry, see above. Set on firmware_register(),
   82          * cleared on firmware_unregister().
   83          */
   84         struct priv_fw  *parent;
   85 
   86         int             flags;  /* record FIRMWARE_UNLOAD requests */
   87 #define FW_UNLOAD       0x100
   88 
   89         /*
   90          * 'file' is private info managed by the autoload/unload code.
   91          * Set at the end of firmware_get(), cleared only in the
   92          * firmware_task, so the latter can depend on its value even
   93          * while the lock is not held.
   94          */
   95         linker_file_t   file;   /* module file, if autoloaded */
   96 
   97         /*
   98          * 'fw' is the externally visible image information.
   99          * We do not make it the first field in priv_fw, to avoid the
  100          * temptation of casting pointers to each other.
  101          * Use PRIV_FW(fw) to get a pointer to the cointainer of fw.
  102          * Beware, PRIV_FW does not work for a NULL pointer.
  103          */
  104         struct firmware fw;     /* externally visible information */
  105 };
  106 
  107 /*
  108  * PRIV_FW returns the pointer to the container of struct firmware *x.
  109  * Cast to intptr_t to override the 'const' attribute of x
  110  */
  111 #define PRIV_FW(x)      ((struct priv_fw *)             \
  112         ((intptr_t)(x) - offsetof(struct priv_fw, fw)) )
  113 
  114 /*
  115  * At the moment we use a static array as backing store for the registry.
  116  * Should we move to a dynamic structure, keep in mind that we cannot
  117  * reallocate the array because pointers are held externally.
  118  * A list may work, though.
  119  */
  120 #define FIRMWARE_MAX    30
  121 static struct priv_fw firmware_table[FIRMWARE_MAX];
  122 
  123 /*
  124  * module release are handled in a separate task as they might sleep.
  125  */
  126 struct task firmware_task;
  127 
  128 /*
  129  * This mutex protects accesses to the firmware table.
  130  */
  131 struct mtx firmware_mtx;
  132 MTX_SYSINIT(firmware, &firmware_mtx, "firmware table", MTX_DEF);
  133 
  134 /*
  135  * Helper function to lookup a name.
  136  * As a side effect, it sets the pointer to a free slot, if any.
  137  * This way we can concentrate most of the registry scanning in
  138  * this function, which makes it easier to replace the registry
  139  * with some other data structure.
  140  */
  141 static struct priv_fw *
  142 lookup(const char *name, struct priv_fw **empty_slot)
  143 {
  144         struct priv_fw *fp = NULL;
  145         struct priv_fw *dummy;
  146         int i;
  147 
  148         if (empty_slot == NULL)
  149                 empty_slot = &dummy;
  150         *empty_slot = NULL;
  151         for (i = 0; i < FIRMWARE_MAX; i++) {
  152                 fp = &firmware_table[i];
  153                 if (fp->fw.name != NULL && strcasecmp(name, fp->fw.name) == 0)
  154                         break;
  155                 else if (!FW_INUSE(fp))
  156                         *empty_slot = fp;
  157         }
  158         return (i < FIRMWARE_MAX ) ? fp : NULL;
  159 }
  160 
  161 /*
  162  * Register a firmware image with the specified name.  The
  163  * image name must not already be registered.  If this is a
  164  * subimage then parent refers to a previously registered
  165  * image that this should be associated with.
  166  */
  167 const struct firmware *
  168 firmware_register(const char *imagename, const void *data, size_t datasize,
  169     unsigned int version, const struct firmware *parent)
  170 {
  171         struct priv_fw *match, *frp;
  172 
  173         mtx_lock(&firmware_mtx);
  174         /*
  175          * Do a lookup to make sure the name is unique or find a free slot.
  176          */
  177         match = lookup(imagename, &frp);
  178         if (match != NULL) {
  179                 mtx_unlock(&firmware_mtx);
  180                 printf("%s: image %s already registered!\n",
  181                         __func__, imagename);
  182                 return NULL;
  183         }
  184         if (frp == NULL) {
  185                 mtx_unlock(&firmware_mtx);
  186                 printf("%s: cannot register image %s, firmware table full!\n",
  187                     __func__, imagename);
  188                 return NULL;
  189         }
  190         bzero(frp, sizeof(frp));        /* start from a clean record */
  191         frp->fw.name = imagename;
  192         frp->fw.data = data;
  193         frp->fw.datasize = datasize;
  194         frp->fw.version = version;
  195         if (parent != NULL) {
  196                 frp->parent = PRIV_FW(parent);
  197                 frp->parent->refcnt++;
  198         }
  199         mtx_unlock(&firmware_mtx);
  200         if (bootverbose)
  201                 printf("firmware: '%s' version %u: %zu bytes loaded at %p\n",
  202                     imagename, version, datasize, data);
  203         return &frp->fw;
  204 }
  205 
  206 /*
  207  * Unregister/remove a firmware image.  If there are outstanding
  208  * references an error is returned and the image is not removed
  209  * from the registry.
  210  */
  211 int
  212 firmware_unregister(const char *imagename)
  213 {
  214         struct priv_fw *fp;
  215         int err;
  216 
  217         mtx_lock(&firmware_mtx);
  218         fp = lookup(imagename, NULL);
  219         if (fp == NULL) {
  220                 /*
  221                  * It is ok for the lookup to fail; this can happen
  222                  * when a module is unloaded on last reference and the
  223                  * module unload handler unregister's each of it's
  224                  * firmware images.
  225                  */
  226                 err = 0;
  227         } else if (fp->refcnt != 0) {   /* cannot unregister */
  228                 err = EBUSY;
  229         }  else {
  230                 linker_file_t   x = fp->file;   /* save value */
  231 
  232                 if (fp->parent != NULL) /* release parent reference */
  233                         fp->parent->refcnt--;
  234                 /*
  235                  * Clear the whole entry with bzero to make sure we
  236                  * do not forget anything. Then restore 'file' which is
  237                  * non-null for autoloaded images.
  238                  */
  239                 bzero(fp, sizeof(struct priv_fw));
  240                 fp->file = x;
  241                 err = 0;
  242         }
  243         mtx_unlock(&firmware_mtx);
  244         return err;
  245 }
  246 
  247 /*
  248  * Lookup and potentially load the specified firmware image.
  249  * If the firmware is not found in the registry, try to load a kernel
  250  * module named as the image name.
  251  * If the firmware is located, a reference is returned. The caller must
  252  * release this reference for the image to be eligible for removal/unload.
  253  */
  254 const struct firmware *
  255 firmware_get(const char *imagename)
  256 {
  257         struct thread *td;
  258         struct priv_fw *fp;
  259         linker_file_t result;
  260 
  261         mtx_lock(&firmware_mtx);
  262         fp = lookup(imagename, NULL);
  263         if (fp != NULL)
  264                 goto found;
  265         /*
  266          * Image not present, try to load the module holding it.
  267          */
  268         mtx_unlock(&firmware_mtx);
  269         td = curthread;
  270         if (priv_check(td, PRIV_FIRMWARE_LOAD) != 0 ||
  271             securelevel_gt(td->td_ucred, 0) != 0) {
  272                 printf("%s: insufficient privileges to "
  273                     "load firmware image %s\n", __func__, imagename);
  274                 return NULL;
  275         }
  276         (void) linker_reference_module(imagename, NULL, &result);
  277         /*
  278          * After loading the module, see if the image is registered now.
  279          */
  280         mtx_lock(&firmware_mtx);
  281         fp = lookup(imagename, NULL);
  282         if (fp == NULL) {
  283                 mtx_unlock(&firmware_mtx);
  284                 printf("%s: failed to load firmware image %s\n",
  285                         __func__, imagename);
  286                 (void) linker_release_module(imagename, NULL, NULL);
  287                 return NULL;
  288         }
  289         fp->file = result;      /* record the module identity */
  290 
  291 found:                          /* common exit point on success */
  292         fp->refcnt++;
  293         mtx_unlock(&firmware_mtx);
  294         return &fp->fw;
  295 }
  296 
  297 /*
  298  * Release a reference to a firmware image returned by firmware_get.
  299  * The caller may specify, with the FIRMWARE_UNLOAD flag, its desire
  300  * to release the resource, but the flag is only advisory.
  301  *
  302  * If this is the last reference to the firmware image, and this is an
  303  * autoloaded module, wake up the firmware_task to figure out what to do
  304  * with the associated module.
  305  */
  306 void
  307 firmware_put(const struct firmware *p, int flags)
  308 {
  309         struct priv_fw *fp = PRIV_FW(p);
  310 
  311         mtx_lock(&firmware_mtx);
  312         fp->refcnt--;
  313         if (fp->refcnt == 0) {
  314                 if (flags & FIRMWARE_UNLOAD)
  315                         fp->flags |= FW_UNLOAD;
  316                 if (fp->file)
  317                         taskqueue_enqueue(taskqueue_thread, &firmware_task);
  318         }
  319         mtx_unlock(&firmware_mtx);
  320 }
  321 
  322 /*
  323  * The body of the task in charge of unloading autoloaded modules
  324  * that are not needed anymore.
  325  * Images can be cross-linked so we may need to make multiple passes,
  326  * but the time we spend in the loop is bounded because we clear entries
  327  * as we touch them.
  328  */
  329 static void
  330 unloadentry(void *unused1, int unused2)
  331 {
  332         int limit = FIRMWARE_MAX;
  333         int i;  /* current cycle */
  334 
  335         mtx_lock(&firmware_mtx);
  336         /*
  337          * Scan the table. limit is set to make sure we make another
  338          * full sweep after matching an entry that requires unloading.
  339          */
  340         for (i = 0; i < limit; i++) {
  341                 struct priv_fw *fp;
  342                 int err;
  343 
  344                 fp = &firmware_table[i % FIRMWARE_MAX];
  345                 if (fp->fw.name == NULL || fp->file == NULL ||
  346                     fp->refcnt != 0 || (fp->flags & FW_UNLOAD) == 0)
  347                         continue;
  348 
  349                 /*
  350                  * Found an entry. Now:
  351                  * 1. bump up limit to make sure we make another full round;
  352                  * 2. clear FW_UNLOAD so we don't try this entry again.
  353                  * 3. release the lock while trying to unload the module.
  354                  * 'file' remains set so that the entry cannot be reused
  355                  * in the meantime (it also means that fp->file will
  356                  * not change while we release the lock).
  357                  */
  358                 limit = i + FIRMWARE_MAX;       /* make another full round */
  359                 fp->flags &= ~FW_UNLOAD;        /* do not try again */
  360 
  361                 mtx_unlock(&firmware_mtx);
  362                 err = linker_release_module(NULL, NULL, fp->file);
  363                 mtx_lock(&firmware_mtx);
  364 
  365                 /*
  366                  * We rely on the module to call firmware_unregister()
  367                  * on unload to actually release the entry.
  368                  * If err = 0 we can drop our reference as the system
  369                  * accepted it. Otherwise unloading failed (e.g. the
  370                  * module itself gave an error) so our reference is
  371                  * still valid.
  372                  */
  373                 if (err == 0)
  374                         fp->file = NULL; 
  375         }
  376         mtx_unlock(&firmware_mtx);
  377 }
  378 
  379 /*
  380  * Module glue.
  381  */
  382 static int
  383 firmware_modevent(module_t mod, int type, void *unused)
  384 {
  385         struct priv_fw *fp;
  386         int i, err = EINVAL;
  387 
  388         switch (type) {
  389         case MOD_LOAD:
  390                 TASK_INIT(&firmware_task, 0, unloadentry, NULL);
  391                 return 0;
  392 
  393         case MOD_UNLOAD:
  394                 /* request all autoloaded modules to be released */
  395                 mtx_lock(&firmware_mtx);
  396                 for (i = 0; i < FIRMWARE_MAX; i++) {
  397                         fp = &firmware_table[i];
  398                         fp->flags |= FW_UNLOAD;;
  399                 }
  400                 mtx_unlock(&firmware_mtx);
  401                 taskqueue_enqueue(taskqueue_thread, &firmware_task);
  402                 taskqueue_drain(taskqueue_thread, &firmware_task);
  403                 for (i = 0; i < FIRMWARE_MAX; i++) {
  404                         fp = &firmware_table[i];
  405                         if (fp->fw.name != NULL) {
  406                                 printf("%s: image %p ref %d still active slot %d\n",
  407                                         __func__, fp->fw.name,
  408                                         fp->refcnt,  i);
  409                                 err = EINVAL;
  410                         }
  411                 }
  412                 return err;
  413         }
  414         return EINVAL;
  415 }
  416 
  417 static moduledata_t firmware_mod = {
  418         "firmware",
  419         firmware_modevent,
  420         0
  421 };
  422 DECLARE_MODULE(firmware, firmware_mod, SI_SUB_DRIVERS, SI_ORDER_FIRST);
  423 MODULE_VERSION(firmware, 1);

Cache object: f7b64fe11acdaa94b5f94f27f873b1ec


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]


This page is part of the FreeBSD/Linux Linux Kernel Cross-Reference, and was automatically generated using a modified version of the LXR engine.