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-12-STABLE  -  FREEBSD-12-0  -  FREEBSD-11-STABLE  -  FREEBSD-11-2  -  FREEBSD-11-1  -  FREEBSD-11-0  -  FREEBSD-10-STABLE  -  FREEBSD-10-4  -  FREEBSD-10-3  -  FREEBSD-10-2  -  FREEBSD-10-1  -  FREEBSD-10-0  -  FREEBSD-9-STABLE  -  FREEBSD-9-3  -  FREEBSD-9-2  -  FREEBSD-9-1  -  FREEBSD-9-0  -  FREEBSD-8-STABLE  -  FREEBSD-8-4  -  FREEBSD-8-3  -  FREEBSD-8-2  -  FREEBSD-8-1  -  FREEBSD-8-0  -  FREEBSD-7-STABLE  -  FREEBSD-7-4  -  FREEBSD-7-3  -  FREEBSD-7-2  -  FREEBSD-7-1  -  FREEBSD-7-0  -  FREEBSD-6-STABLE  -  FREEBSD-6-4  -  FREEBSD-6-3  -  FREEBSD-6-2  -  FREEBSD-6-1  -  FREEBSD-6-0  -  FREEBSD-5-STABLE  -  FREEBSD-5-5  -  FREEBSD-5-4  -  FREEBSD-5-3  -  FREEBSD-5-2  -  FREEBSD-5-1  -  FREEBSD-5-0  -  FREEBSD-4-STABLE  -  FREEBSD-3-STABLE  -  FREEBSD22  -  linux-2.6  -  linux-2.4.22  -  MK83  -  MK84  -  PLAN9  -  DFBSD  -  NETBSD  -  NETBSD5  -  NETBSD4  -  NETBSD3  -  NETBSD20  -  OPENBSD  -  xnu-517  -  xnu-792  -  xnu-792.6.70  -  xnu-1228  -  xnu-1456.1.26  -  xnu-1699.24.8  -  xnu-2050.18.24  -  OPENSOLARIS  -  minix-3-1-1 
SearchContext: -  none  -  3  -  10 

    1 /*-
    2  * Copyright (c) 2005-2008, 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: stable/10/sys/kern/subr_firmware.c 355419 2019-12-05 14:53:46Z hselasky $");
   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 #include <sys/eventhandler.h>
   45 
   46 #include <sys/filedesc.h>
   47 #include <sys/vnode.h>
   48 
   49 /*
   50  * Loadable firmware support. See sys/sys/firmware.h and firmware(9)
   51  * form more details on the subsystem.
   52  *
   53  * 'struct firmware' is the user-visible part of the firmware table.
   54  * Additional internal information is stored in a 'struct priv_fw'
   55  * (currently a static array). A slot is in use if FW_INUSE is true:
   56  */
   57 
   58 #define FW_INUSE(p)     ((p)->file != NULL || (p)->fw.name != NULL)
   59 
   60 /*
   61  * fw.name != NULL when an image is registered; file != NULL for
   62  * autoloaded images whose handling has not been completed.
   63  *
   64  * The state of a slot evolves as follows:
   65  *      firmware_register       -->  fw.name = image_name
   66  *      (autoloaded image)      -->  file = module reference
   67  *      firmware_unregister     -->  fw.name = NULL
   68  *      (unloadentry complete)  -->  file = NULL
   69  *
   70  * In order for the above to work, the 'file' field must remain
   71  * unchanged in firmware_unregister().
   72  *
   73  * Images residing in the same module are linked to each other
   74  * through the 'parent' argument of firmware_register().
   75  * One image (typically, one with the same name as the module to let
   76  * the autoloading mechanism work) is considered the parent image for
   77  * all other images in the same module. Children affect the refcount
   78  * on the parent image preventing improper unloading of the image itself.
   79  */
   80 
   81 struct priv_fw {
   82         int             refcnt;         /* reference count */
   83 
   84         /*
   85          * parent entry, see above. Set on firmware_register(),
   86          * cleared on firmware_unregister().
   87          */
   88         struct priv_fw  *parent;
   89 
   90         int             flags;  /* record FIRMWARE_UNLOAD requests */
   91 #define FW_UNLOAD       0x100
   92 
   93         /*
   94          * 'file' is private info managed by the autoload/unload code.
   95          * Set at the end of firmware_get(), cleared only in the
   96          * firmware_unload_task, so the latter can depend on its value even
   97          * while the lock is not held.
   98          */
   99         linker_file_t   file;   /* module file, if autoloaded */
  100 
  101         /*
  102          * 'fw' is the externally visible image information.
  103          * We do not make it the first field in priv_fw, to avoid the
  104          * temptation of casting pointers to each other.
  105          * Use PRIV_FW(fw) to get a pointer to the cointainer of fw.
  106          * Beware, PRIV_FW does not work for a NULL pointer.
  107          */
  108         struct firmware fw;     /* externally visible information */
  109 };
  110 
  111 /*
  112  * PRIV_FW returns the pointer to the container of struct firmware *x.
  113  * Cast to intptr_t to override the 'const' attribute of x
  114  */
  115 #define PRIV_FW(x)      ((struct priv_fw *)             \
  116         ((intptr_t)(x) - offsetof(struct priv_fw, fw)) )
  117 
  118 /*
  119  * At the moment we use a static array as backing store for the registry.
  120  * Should we move to a dynamic structure, keep in mind that we cannot
  121  * reallocate the array because pointers are held externally.
  122  * A list may work, though.
  123  */
  124 #define FIRMWARE_MAX    50
  125 static struct priv_fw firmware_table[FIRMWARE_MAX];
  126 
  127 /*
  128  * Firmware module operations are handled in a separate task as they
  129  * might sleep and they require directory context to do i/o.
  130  */
  131 static struct taskqueue *firmware_tq;
  132 static struct task firmware_unload_task;
  133 
  134 /*
  135  * This mutex protects accesses to the firmware table.
  136  */
  137 static struct mtx firmware_mtx;
  138 MTX_SYSINIT(firmware, &firmware_mtx, "firmware table", MTX_DEF);
  139 
  140 /*
  141  * Helper function to lookup a name.
  142  * As a side effect, it sets the pointer to a free slot, if any.
  143  * This way we can concentrate most of the registry scanning in
  144  * this function, which makes it easier to replace the registry
  145  * with some other data structure.
  146  */
  147 static struct priv_fw *
  148 lookup(const char *name, struct priv_fw **empty_slot)
  149 {
  150         struct priv_fw *fp = NULL;
  151         struct priv_fw *dummy;
  152         int i;
  153 
  154         if (empty_slot == NULL)
  155                 empty_slot = &dummy;
  156         *empty_slot = NULL;
  157         for (i = 0; i < FIRMWARE_MAX; i++) {
  158                 fp = &firmware_table[i];
  159                 if (fp->fw.name != NULL && strcasecmp(name, fp->fw.name) == 0)
  160                         break;
  161                 else if (!FW_INUSE(fp))
  162                         *empty_slot = fp;
  163         }
  164         return (i < FIRMWARE_MAX ) ? fp : NULL;
  165 }
  166 
  167 /*
  168  * Register a firmware image with the specified name.  The
  169  * image name must not already be registered.  If this is a
  170  * subimage then parent refers to a previously registered
  171  * image that this should be associated with.
  172  */
  173 const struct firmware *
  174 firmware_register(const char *imagename, const void *data, size_t datasize,
  175     unsigned int version, const struct firmware *parent)
  176 {
  177         struct priv_fw *match, *frp;
  178         char *str;
  179 
  180         str = strdup(imagename, M_TEMP);
  181 
  182         mtx_lock(&firmware_mtx);
  183         /*
  184          * Do a lookup to make sure the name is unique or find a free slot.
  185          */
  186         match = lookup(imagename, &frp);
  187         if (match != NULL) {
  188                 mtx_unlock(&firmware_mtx);
  189                 printf("%s: image %s already registered!\n",
  190                         __func__, imagename);
  191                 free(str, M_TEMP);
  192                 return NULL;
  193         }
  194         if (frp == NULL) {
  195                 mtx_unlock(&firmware_mtx);
  196                 printf("%s: cannot register image %s, firmware table full!\n",
  197                     __func__, imagename);
  198                 free(str, M_TEMP);
  199                 return NULL;
  200         }
  201         bzero(frp, sizeof(*frp));       /* start from a clean record */
  202         frp->fw.name = str;
  203         frp->fw.data = data;
  204         frp->fw.datasize = datasize;
  205         frp->fw.version = version;
  206         if (parent != NULL)
  207                 frp->parent = PRIV_FW(parent);
  208         mtx_unlock(&firmware_mtx);
  209         if (bootverbose)
  210                 printf("firmware: '%s' version %u: %zu bytes loaded at %p\n",
  211                     imagename, version, datasize, data);
  212         return &frp->fw;
  213 }
  214 
  215 /*
  216  * Unregister/remove a firmware image.  If there are outstanding
  217  * references an error is returned and the image is not removed
  218  * from the registry.
  219  */
  220 int
  221 firmware_unregister(const char *imagename)
  222 {
  223         struct priv_fw *fp;
  224         int err;
  225 
  226         mtx_lock(&firmware_mtx);
  227         fp = lookup(imagename, NULL);
  228         if (fp == NULL) {
  229                 /*
  230                  * It is ok for the lookup to fail; this can happen
  231                  * when a module is unloaded on last reference and the
  232                  * module unload handler unregister's each of it's
  233                  * firmware images.
  234                  */
  235                 err = 0;
  236         } else if (fp->refcnt != 0) {   /* cannot unregister */
  237                 err = EBUSY;
  238         } else {
  239                 linker_file_t x = fp->file;     /* save value */
  240 
  241                 /*
  242                  * Clear the whole entry with bzero to make sure we
  243                  * do not forget anything. Then restore 'file' which is
  244                  * non-null for autoloaded images.
  245                  */
  246                 free((void *) (uintptr_t) fp->fw.name, M_TEMP);
  247                 bzero(fp, sizeof(struct priv_fw));
  248                 fp->file = x;
  249                 err = 0;
  250         }
  251         mtx_unlock(&firmware_mtx);
  252         return err;
  253 }
  254 
  255 static void
  256 loadimage(void *arg, int npending)
  257 {
  258         char *imagename = arg;
  259         struct priv_fw *fp;
  260         linker_file_t result;
  261         int error;
  262 
  263         /* synchronize with the thread that dispatched us */
  264         mtx_lock(&firmware_mtx);
  265         mtx_unlock(&firmware_mtx);
  266 
  267         error = linker_reference_module(imagename, NULL, &result);
  268         if (error != 0) {
  269                 printf("%s: could not load firmware image, error %d\n",
  270                     imagename, error);
  271                 goto done;
  272         }
  273 
  274         mtx_lock(&firmware_mtx);
  275         fp = lookup(imagename, NULL);
  276         if (fp == NULL || fp->file != NULL) {
  277                 mtx_unlock(&firmware_mtx);
  278                 if (fp == NULL)
  279                         printf("%s: firmware image loaded, "
  280                             "but did not register\n", imagename);
  281                 (void) linker_release_module(imagename, NULL, NULL);
  282                 goto done;
  283         }
  284         fp->file = result;      /* record the module identity */
  285         mtx_unlock(&firmware_mtx);
  286 done:
  287         wakeup_one(imagename);          /* we're done */
  288 }
  289 
  290 /*
  291  * Lookup and potentially load the specified firmware image.
  292  * If the firmware is not found in the registry, try to load a kernel
  293  * module named as the image name.
  294  * If the firmware is located, a reference is returned. The caller must
  295  * release this reference for the image to be eligible for removal/unload.
  296  */
  297 const struct firmware *
  298 firmware_get(const char *imagename)
  299 {
  300         struct task fwload_task;
  301         struct thread *td;
  302         struct priv_fw *fp;
  303 
  304         mtx_lock(&firmware_mtx);
  305         fp = lookup(imagename, NULL);
  306         if (fp != NULL)
  307                 goto found;
  308         /*
  309          * Image not present, try to load the module holding it.
  310          */
  311         td = curthread;
  312         if (priv_check(td, PRIV_FIRMWARE_LOAD) != 0 ||
  313             securelevel_gt(td->td_ucred, 0) != 0) {
  314                 mtx_unlock(&firmware_mtx);
  315                 printf("%s: insufficient privileges to "
  316                     "load firmware image %s\n", __func__, imagename);
  317                 return NULL;
  318         }
  319         /* 
  320          * Defer load to a thread with known context.  linker_reference_module
  321          * may do filesystem i/o which requires root & current dirs, etc.
  322          * Also we must not hold any mtx's over this call which is problematic.
  323          */
  324         if (!cold) {
  325                 TASK_INIT(&fwload_task, 0, loadimage, __DECONST(void *,
  326                     imagename));
  327                 taskqueue_enqueue(firmware_tq, &fwload_task);
  328                 msleep(__DECONST(void *, imagename), &firmware_mtx, 0,
  329                     "fwload", 0);
  330         }
  331         /*
  332          * After attempting to load the module, see if the image is registered.
  333          */
  334         fp = lookup(imagename, NULL);
  335         if (fp == NULL) {
  336                 mtx_unlock(&firmware_mtx);
  337                 return NULL;
  338         }
  339 found:                          /* common exit point on success */
  340         if (fp->refcnt == 0 && fp->parent != NULL)
  341                 fp->parent->refcnt++;
  342         fp->refcnt++;
  343         mtx_unlock(&firmware_mtx);
  344         return &fp->fw;
  345 }
  346 
  347 /*
  348  * Release a reference to a firmware image returned by firmware_get.
  349  * The caller may specify, with the FIRMWARE_UNLOAD flag, its desire
  350  * to release the resource, but the flag is only advisory.
  351  *
  352  * If this is the last reference to the firmware image, and this is an
  353  * autoloaded module, wake up the firmware_unload_task to figure out
  354  * what to do with the associated module.
  355  */
  356 void
  357 firmware_put(const struct firmware *p, int flags)
  358 {
  359         struct priv_fw *fp = PRIV_FW(p);
  360 
  361         mtx_lock(&firmware_mtx);
  362         fp->refcnt--;
  363         if (fp->refcnt == 0) {
  364                 if (fp->parent != NULL)
  365                         fp->parent->refcnt--;
  366                 if (flags & FIRMWARE_UNLOAD)
  367                         fp->flags |= FW_UNLOAD;
  368                 if (fp->file)
  369                         taskqueue_enqueue(firmware_tq, &firmware_unload_task);
  370         }
  371         mtx_unlock(&firmware_mtx);
  372 }
  373 
  374 /*
  375  * Setup directory state for the firmware_tq thread so we can do i/o.
  376  */
  377 static void
  378 set_rootvnode(void *arg, int npending)
  379 {
  380         struct thread *td = curthread;
  381         struct proc *p = td->td_proc;
  382 
  383         FILEDESC_XLOCK(p->p_fd);
  384         if (p->p_fd->fd_cdir == NULL) {
  385                 p->p_fd->fd_cdir = rootvnode;
  386                 VREF(rootvnode);
  387         }
  388         if (p->p_fd->fd_rdir == NULL) {
  389                 p->p_fd->fd_rdir = rootvnode;
  390                 VREF(rootvnode);
  391         }
  392         FILEDESC_XUNLOCK(p->p_fd);
  393 
  394         free(arg, M_TEMP);
  395 }
  396 
  397 /*
  398  * Event handler called on mounting of /; bounce a task
  399  * into the task queue thread to setup it's directories.
  400  */
  401 static void
  402 firmware_mountroot(void *arg)
  403 {
  404         struct task *setroot_task;
  405 
  406         setroot_task = malloc(sizeof(struct task), M_TEMP, M_NOWAIT);
  407         if (setroot_task != NULL) {
  408                 TASK_INIT(setroot_task, 0, set_rootvnode, setroot_task);
  409                 taskqueue_enqueue(firmware_tq, setroot_task);
  410         } else
  411                 printf("%s: no memory for task!\n", __func__);
  412 }
  413 EVENTHANDLER_DEFINE(mountroot, firmware_mountroot, NULL, 0);
  414 
  415 /*
  416  * The body of the task in charge of unloading autoloaded modules
  417  * that are not needed anymore.
  418  * Images can be cross-linked so we may need to make multiple passes,
  419  * but the time we spend in the loop is bounded because we clear entries
  420  * as we touch them.
  421  */
  422 static void
  423 unloadentry(void *unused1, int unused2)
  424 {
  425         int limit = FIRMWARE_MAX;
  426         int i;  /* current cycle */
  427 
  428         mtx_lock(&firmware_mtx);
  429         /*
  430          * Scan the table. limit is set to make sure we make another
  431          * full sweep after matching an entry that requires unloading.
  432          */
  433         for (i = 0; i < limit; i++) {
  434                 struct priv_fw *fp;
  435                 int err;
  436 
  437                 fp = &firmware_table[i % FIRMWARE_MAX];
  438                 if (fp->fw.name == NULL || fp->file == NULL ||
  439                     fp->refcnt != 0 || (fp->flags & FW_UNLOAD) == 0)
  440                         continue;
  441 
  442                 /*
  443                  * Found an entry. Now:
  444                  * 1. bump up limit to make sure we make another full round;
  445                  * 2. clear FW_UNLOAD so we don't try this entry again.
  446                  * 3. release the lock while trying to unload the module.
  447                  * 'file' remains set so that the entry cannot be reused
  448                  * in the meantime (it also means that fp->file will
  449                  * not change while we release the lock).
  450                  */
  451                 limit = i + FIRMWARE_MAX;       /* make another full round */
  452                 fp->flags &= ~FW_UNLOAD;        /* do not try again */
  453 
  454                 mtx_unlock(&firmware_mtx);
  455                 err = linker_release_module(NULL, NULL, fp->file);
  456                 mtx_lock(&firmware_mtx);
  457 
  458                 /*
  459                  * We rely on the module to call firmware_unregister()
  460                  * on unload to actually release the entry.
  461                  * If err = 0 we can drop our reference as the system
  462                  * accepted it. Otherwise unloading failed (e.g. the
  463                  * module itself gave an error) so our reference is
  464                  * still valid.
  465                  */
  466                 if (err == 0)
  467                         fp->file = NULL; 
  468         }
  469         mtx_unlock(&firmware_mtx);
  470 }
  471 
  472 /*
  473  * Module glue.
  474  */
  475 static int
  476 firmware_modevent(module_t mod, int type, void *unused)
  477 {
  478         struct priv_fw *fp;
  479         int i, err;
  480 
  481         switch (type) {
  482         case MOD_LOAD:
  483                 TASK_INIT(&firmware_unload_task, 0, unloadentry, NULL);
  484                 firmware_tq = taskqueue_create("taskqueue_firmware", M_WAITOK,
  485                     taskqueue_thread_enqueue, &firmware_tq);
  486                 /* NB: use our own loop routine that sets up context */
  487                 (void) taskqueue_start_threads(&firmware_tq, 1, PWAIT,
  488                     "firmware taskq");
  489                 if (rootvnode != NULL) {
  490                         /* 
  491                          * Root is already mounted so we won't get an event;
  492                          * simulate one here.
  493                          */
  494                         firmware_mountroot(NULL);
  495                 }
  496                 return 0;
  497 
  498         case MOD_UNLOAD:
  499                 /* request all autoloaded modules to be released */
  500                 mtx_lock(&firmware_mtx);
  501                 for (i = 0; i < FIRMWARE_MAX; i++) {
  502                         fp = &firmware_table[i];
  503                         fp->flags |= FW_UNLOAD;
  504                 }
  505                 mtx_unlock(&firmware_mtx);
  506                 taskqueue_enqueue(firmware_tq, &firmware_unload_task);
  507                 taskqueue_drain(firmware_tq, &firmware_unload_task);
  508                 err = 0;
  509                 for (i = 0; i < FIRMWARE_MAX; i++) {
  510                         fp = &firmware_table[i];
  511                         if (fp->fw.name != NULL) {
  512                                 printf("%s: image %p ref %d still active slot %d\n",
  513                                         __func__, fp->fw.name,
  514                                         fp->refcnt,  i);
  515                                 err = EINVAL;
  516                         }
  517                 }
  518                 if (err == 0)
  519                         taskqueue_free(firmware_tq);
  520                 return err;
  521         }
  522         return EINVAL;
  523 }
  524 
  525 static moduledata_t firmware_mod = {
  526         "firmware",
  527         firmware_modevent,
  528         NULL
  529 };
  530 DECLARE_MODULE(firmware, firmware_mod, SI_SUB_DRIVERS, SI_ORDER_FIRST);
  531 MODULE_VERSION(firmware, 1);

Cache object: b772d95fd7b9b00aeedee751fecf2e21


[ 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.