/*- * SPDX-License-Identifier: BSD-2-Clause-FreeBSD * * Copyright (c) 2005-2008, Sam Leffler * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice unmodified, this list of conditions, and the following * disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ #include __FBSDID("$FreeBSD$"); #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* * Loadable firmware support. See sys/sys/firmware.h and firmware(9) * form more details on the subsystem. * * 'struct firmware' is the user-visible part of the firmware table. * Additional internal information is stored in a 'struct priv_fw', * which embeds the public firmware structure. */ /* * fw.name != NULL when an image is registered; file != NULL for * autoloaded images whose handling has not been completed. * * The state of a slot evolves as follows: * firmware_register --> fw.name = image_name * (autoloaded image) --> file = module reference * firmware_unregister --> fw.name = NULL * (unloadentry complete) --> file = NULL * * In order for the above to work, the 'file' field must remain * unchanged in firmware_unregister(). * * Images residing in the same module are linked to each other * through the 'parent' argument of firmware_register(). * One image (typically, one with the same name as the module to let * the autoloading mechanism work) is considered the parent image for * all other images in the same module. Children affect the refcount * on the parent image preventing improper unloading of the image itself. */ struct priv_fw { int refcnt; /* reference count */ LIST_ENTRY(priv_fw) link; /* table linkage */ /* * parent entry, see above. Set on firmware_register(), * cleared on firmware_unregister(). */ struct priv_fw *parent; int flags; /* record FIRMWARE_UNLOAD requests */ #define FW_UNLOAD 0x100 /* * 'file' is private info managed by the autoload/unload code. * Set at the end of firmware_get(), cleared only in the * firmware_unload_task, so the latter can depend on its value even * while the lock is not held. */ linker_file_t file; /* module file, if autoloaded */ /* * 'fw' is the externally visible image information. * We do not make it the first field in priv_fw, to avoid the * temptation of casting pointers to each other. * Use PRIV_FW(fw) to get a pointer to the cointainer of fw. * Beware, PRIV_FW does not work for a NULL pointer. */ struct firmware fw; /* externally visible information */ }; /* * PRIV_FW returns the pointer to the container of struct firmware *x. * Cast to intptr_t to override the 'const' attribute of x */ #define PRIV_FW(x) ((struct priv_fw *) \ ((intptr_t)(x) - offsetof(struct priv_fw, fw)) ) /* * Global firmware image registry. */ static LIST_HEAD(, priv_fw) firmware_table; /* * Firmware module operations are handled in a separate task as they * might sleep and they require directory context to do i/o. */ static struct taskqueue *firmware_tq; static struct task firmware_unload_task; /* * This mutex protects accesses to the firmware table. */ static struct mtx firmware_mtx; MTX_SYSINIT(firmware, &firmware_mtx, "firmware table", MTX_DEF); static MALLOC_DEFINE(M_FIRMWARE, "firmware", "device firmware images"); /* * Helper function to lookup a name. * As a side effect, it sets the pointer to a free slot, if any. * This way we can concentrate most of the registry scanning in * this function, which makes it easier to replace the registry * with some other data structure. */ static struct priv_fw * lookup(const char *name) { struct priv_fw *fp; mtx_assert(&firmware_mtx, MA_OWNED); LIST_FOREACH(fp, &firmware_table, link) { if (fp->fw.name != NULL && strcasecmp(name, fp->fw.name) == 0) break; } return (fp); } /* * Register a firmware image with the specified name. The * image name must not already be registered. If this is a * subimage then parent refers to a previously registered * image that this should be associated with. */ const struct firmware * firmware_register(const char *imagename, const void *data, size_t datasize, unsigned int version, const struct firmware *parent) { struct priv_fw *frp; char *name; mtx_lock(&firmware_mtx); frp = lookup(imagename); if (frp != NULL) { mtx_unlock(&firmware_mtx); printf("%s: image %s already registered!\n", __func__, imagename); return (NULL); } mtx_unlock(&firmware_mtx); frp = malloc(sizeof(*frp), M_FIRMWARE, M_WAITOK | M_ZERO); name = strdup(imagename, M_FIRMWARE); mtx_lock(&firmware_mtx); if (lookup(imagename) != NULL) { /* We lost a race. */ mtx_unlock(&firmware_mtx); free(name, M_FIRMWARE); free(frp, M_FIRMWARE); return (NULL); } frp->fw.name = name; frp->fw.data = data; frp->fw.datasize = datasize; frp->fw.version = version; if (parent != NULL) frp->parent = PRIV_FW(parent); LIST_INSERT_HEAD(&firmware_table, frp, link); mtx_unlock(&firmware_mtx); if (bootverbose) printf("firmware: '%s' version %u: %zu bytes loaded at %p\n", imagename, version, datasize, data); return (&frp->fw); } /* * Unregister/remove a firmware image. If there are outstanding * references an error is returned and the image is not removed * from the registry. */ int firmware_unregister(const char *imagename) { struct priv_fw *fp; int err; mtx_lock(&firmware_mtx); fp = lookup(imagename); if (fp == NULL) { /* * It is ok for the lookup to fail; this can happen * when a module is unloaded on last reference and the * module unload handler unregister's each of its * firmware images. */ err = 0; } else if (fp->refcnt != 0) { /* cannot unregister */ err = EBUSY; } else { LIST_REMOVE(fp, link); free(__DECONST(char *, fp->fw.name), M_FIRMWARE); free(fp, M_FIRMWARE); err = 0; } mtx_unlock(&firmware_mtx); return (err); } static void loadimage(void *arg, int npending) { char *imagename = arg; struct priv_fw *fp; linker_file_t result; int error; error = linker_reference_module(imagename, NULL, &result); if (error != 0) { printf("%s: could not load firmware image, error %d\n", imagename, error); mtx_lock(&firmware_mtx); goto done; } mtx_lock(&firmware_mtx); fp = lookup(imagename); if (fp == NULL || fp->file != NULL) { mtx_unlock(&firmware_mtx); if (fp == NULL) printf("%s: firmware image loaded, " "but did not register\n", imagename); (void) linker_release_module(imagename, NULL, NULL); mtx_lock(&firmware_mtx); goto done; } fp->file = result; /* record the module identity */ done: wakeup_one(imagename); mtx_unlock(&firmware_mtx); } /* * Lookup and potentially load the specified firmware image. * If the firmware is not found in the registry, try to load a kernel * module named as the image name. * If the firmware is located, a reference is returned. The caller must * release this reference for the image to be eligible for removal/unload. */ const struct firmware * firmware_get(const char *imagename) { struct task fwload_task; struct thread *td; struct priv_fw *fp; mtx_lock(&firmware_mtx); fp = lookup(imagename); if (fp != NULL) goto found; /* * Image not present, try to load the module holding it. */ td = curthread; if (priv_check(td, PRIV_FIRMWARE_LOAD) != 0 || securelevel_gt(td->td_ucred, 0) != 0) { mtx_unlock(&firmware_mtx); printf("%s: insufficient privileges to " "load firmware image %s\n", __func__, imagename); return NULL; } /* * Defer load to a thread with known context. linker_reference_module * may do filesystem i/o which requires root & current dirs, etc. * Also we must not hold any mtx's over this call which is problematic. */ if (!cold) { TASK_INIT(&fwload_task, 0, loadimage, __DECONST(void *, imagename)); taskqueue_enqueue(firmware_tq, &fwload_task); msleep(__DECONST(void *, imagename), &firmware_mtx, 0, "fwload", 0); } /* * After attempting to load the module, see if the image is registered. */ fp = lookup(imagename); if (fp == NULL) { mtx_unlock(&firmware_mtx); return NULL; } found: /* common exit point on success */ if (fp->refcnt == 0 && fp->parent != NULL) fp->parent->refcnt++; fp->refcnt++; mtx_unlock(&firmware_mtx); return &fp->fw; } /* * Release a reference to a firmware image returned by firmware_get. * The caller may specify, with the FIRMWARE_UNLOAD flag, its desire * to release the resource, but the flag is only advisory. * * If this is the last reference to the firmware image, and this is an * autoloaded module, wake up the firmware_unload_task to figure out * what to do with the associated module. */ void firmware_put(const struct firmware *p, int flags) { struct priv_fw *fp = PRIV_FW(p); mtx_lock(&firmware_mtx); fp->refcnt--; if (fp->refcnt == 0) { if (fp->parent != NULL) fp->parent->refcnt--; if (flags & FIRMWARE_UNLOAD) fp->flags |= FW_UNLOAD; if (fp->file) taskqueue_enqueue(firmware_tq, &firmware_unload_task); } mtx_unlock(&firmware_mtx); } /* * Setup directory state for the firmware_tq thread so we can do i/o. */ static void set_rootvnode(void *arg, int npending) { pwd_ensure_dirs(); free(arg, M_TEMP); } /* * Event handler called on mounting of /; bounce a task * into the task queue thread to setup it's directories. */ static void firmware_mountroot(void *arg) { struct task *setroot_task; setroot_task = malloc(sizeof(struct task), M_TEMP, M_NOWAIT); if (setroot_task != NULL) { TASK_INIT(setroot_task, 0, set_rootvnode, setroot_task); taskqueue_enqueue(firmware_tq, setroot_task); } else printf("%s: no memory for task!\n", __func__); } EVENTHANDLER_DEFINE(mountroot, firmware_mountroot, NULL, 0); /* * The body of the task in charge of unloading autoloaded modules * that are not needed anymore. * Images can be cross-linked so we may need to make multiple passes, * but the time we spend in the loop is bounded because we clear entries * as we touch them. */ static void unloadentry(void *unused1, int unused2) { struct priv_fw *fp; int err; mtx_lock(&firmware_mtx); restart: LIST_FOREACH(fp, &firmware_table, link) { if (fp->file == NULL || fp->refcnt != 0 || (fp->flags & FW_UNLOAD) == 0) continue; /* * Found an entry. Now: * 1. make sure we scan the table again * 2. clear FW_UNLOAD so we don't try this entry again. * 3. release the lock while trying to unload the module. */ fp->flags &= ~FW_UNLOAD; /* do not try again */ /* * We rely on the module to call firmware_unregister() * on unload to actually free the entry. */ mtx_unlock(&firmware_mtx); err = linker_release_module(NULL, NULL, fp->file); mtx_lock(&firmware_mtx); /* * When we dropped the lock, another thread could have * removed an element, so we must restart the scan. */ goto restart; } mtx_unlock(&firmware_mtx); } /* * Module glue. */ static int firmware_modevent(module_t mod, int type, void *unused) { struct priv_fw *fp; int err; err = 0; switch (type) { case MOD_LOAD: TASK_INIT(&firmware_unload_task, 0, unloadentry, NULL); firmware_tq = taskqueue_create("taskqueue_firmware", M_WAITOK, taskqueue_thread_enqueue, &firmware_tq); /* NB: use our own loop routine that sets up context */ (void) taskqueue_start_threads(&firmware_tq, 1, PWAIT, "firmware taskq"); if (rootvnode != NULL) { /* * Root is already mounted so we won't get an event; * simulate one here. */ firmware_mountroot(NULL); } break; case MOD_UNLOAD: /* request all autoloaded modules to be released */ mtx_lock(&firmware_mtx); LIST_FOREACH(fp, &firmware_table, link) fp->flags |= FW_UNLOAD; mtx_unlock(&firmware_mtx); taskqueue_enqueue(firmware_tq, &firmware_unload_task); taskqueue_drain(firmware_tq, &firmware_unload_task); LIST_FOREACH(fp, &firmware_table, link) { if (fp->fw.name != NULL) { printf("%s: image %s still active, %d refs\n", __func__, fp->fw.name, fp->refcnt); err = EINVAL; } } if (err == 0) taskqueue_free(firmware_tq); break; default: err = EOPNOTSUPP; break; } return (err); } static moduledata_t firmware_mod = { "firmware", firmware_modevent, NULL }; DECLARE_MODULE(firmware, firmware_mod, SI_SUB_DRIVERS, SI_ORDER_FIRST); MODULE_VERSION(firmware, 1);