/*- * Copyright (c) 2005-2008, Sam Leffler <sam@errno.com> * 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. * * $FreeBSD: src/sys/kern/subr_firmware.c,v 1.13.2.2 2010/02/11 18:34:06 mjacob Exp $ */ #include <sys/param.h> #include <sys/kernel.h> #include <sys/malloc.h> #include <sys/queue.h> #include <sys/taskqueue.h> #include <sys/systm.h> #include <sys/lock.h> #include <sys/spinlock.h> #include <sys/spinlock2.h> #include <sys/errno.h> #include <sys/linker.h> #include <sys/firmware.h> #include <sys/caps.h> #include <sys/proc.h> #include <sys/module.h> #include <sys/eventhandler.h> #include <sys/filedesc.h> #include <sys/vnode.h> /* * 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' * (currently a static array). A slot is in use if FW_INUSE is true: */ #define FW_INUSE(p) ((p)->file != NULL || (p)->fw.name != NULL) /* * 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 */ /* * 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)) ) /* * At the moment we use a static array as backing store for the registry. * Should we move to a dynamic structure, keep in mind that we cannot * reallocate the array because pointers are held externally. * A list may work, though. */ #define FIRMWARE_MAX 30 static struct priv_fw firmware_table[FIRMWARE_MAX]; /* * 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 lock protects accesses to the firmware table. */ static struct lock firmware_lock; /* * 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 **empty_slot) { struct priv_fw *fp = NULL; struct priv_fw *dummy; int i; if (empty_slot == NULL) empty_slot = &dummy; *empty_slot = NULL; for (i = 0; i < FIRMWARE_MAX; i++) { fp = &firmware_table[i]; if (fp->fw.name != NULL && strcasecmp(name, fp->fw.name) == 0) break; else if (!FW_INUSE(fp)) *empty_slot = fp; } return (i < FIRMWARE_MAX ) ? fp : NULL; } /* * 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 *match, *frp; lockmgr(&firmware_lock, LK_EXCLUSIVE); /* * Do a lookup to make sure the name is unique or find a free slot. */ match = lookup(imagename, &frp); if (match != NULL) { lockmgr(&firmware_lock, LK_RELEASE); kprintf("%s: image %s already registered!\n", __func__, imagename); return NULL; } if (frp == NULL) { lockmgr(&firmware_lock, LK_RELEASE); kprintf("%s: cannot register image %s, firmware table full!\n", __func__, imagename); return NULL; } bzero(frp, sizeof(*frp)); /* start from a clean record */ frp->fw.name = imagename; frp->fw.data = data; frp->fw.datasize = datasize; frp->fw.version = version; if (parent != NULL) { frp->parent = PRIV_FW(parent); frp->parent->refcnt++; } lockmgr(&firmware_lock, LK_RELEASE); if (bootverbose) kprintf("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; lockmgr(&firmware_lock, LK_EXCLUSIVE); fp = lookup(imagename, NULL); 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 it's * firmware images. */ err = 0; } else if (fp->refcnt != 0) { /* cannot unregister */ err = EBUSY; } else { linker_file_t x = fp->file; /* save value */ if (fp->parent != NULL) /* release parent reference */ fp->parent->refcnt--; /* * Clear the whole entry with bzero to make sure we * do not forget anything. Then restore 'file' which is * non-null for autoloaded images. */ bzero(fp, sizeof(struct priv_fw)); fp->file = x; err = 0; } lockmgr(&firmware_lock, LK_RELEASE); return err; } static void loadimage(void *arg, int npending) { #ifdef notyet struct thread *td = curthread; #endif char *imagename = arg; struct priv_fw *fp; linker_file_t result; int error; /* synchronize with the thread that dispatched us */ lockmgr(&firmware_lock, LK_EXCLUSIVE); lockmgr(&firmware_lock, LK_RELEASE); /* JAT if (td->td_proc->p_fd->fd_rdir == NULL) { kprintf("%s: root not mounted yet, no way to load image\n", imagename); goto done; } */ error = linker_reference_module(imagename, NULL, &result); if (error != 0) { kprintf("%s: could not load firmware image, error %d\n", imagename, error); goto done; } lockmgr(&firmware_lock, LK_EXCLUSIVE); fp = lookup(imagename, NULL); if (fp == NULL || fp->file != NULL) { lockmgr(&firmware_lock, LK_RELEASE); if (fp == NULL) kprintf("%s: firmware image loaded, " "but did not register\n", imagename); (void) linker_release_module(imagename, NULL, NULL); goto done; } fp->file = result; /* record the module identity */ lockmgr(&firmware_lock, LK_RELEASE); done: wakeup_one(imagename); /* we're done */ } /* * 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 priv_fw *fp; lockmgr(&firmware_lock, LK_EXCLUSIVE); fp = lookup(imagename, NULL); if (fp != NULL) goto found; /* * Image not present, try to load the module holding it. */ if (caps_priv_check_self(SYSCAP_NOKLD) != 0 || securelevel > 0) { lockmgr(&firmware_lock, LK_RELEASE); kprintf("%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 lock's over this call which is problematic. */ if (!cold) { TASK_INIT(&fwload_task, 0, loadimage, __DECONST(void *, imagename)); taskqueue_enqueue(firmware_tq, &fwload_task); lksleep(__DECONST(void *, imagename), &firmware_lock, 0, "fwload", 0); } /* * After attempting to load the module, see if the image is registered. */ fp = lookup(imagename, NULL); if (fp == NULL) { lockmgr(&firmware_lock, LK_RELEASE); return NULL; } found: /* common exit point on success */ fp->refcnt++; lockmgr(&firmware_lock, LK_RELEASE); 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); lockmgr(&firmware_lock, LK_EXCLUSIVE); fp->refcnt--; if (fp->refcnt == 0) { if (flags & FIRMWARE_UNLOAD) fp->flags |= FW_UNLOAD; if (fp->file) taskqueue_enqueue(firmware_tq, &firmware_unload_task); } lockmgr(&firmware_lock, LK_RELEASE); } #ifdef notyet /* * Setup directory state for the firmware_tq thread so we can do i/o. */ static void set_rootvnode(void *arg, int npending) { struct thread *td = curthread; struct proc *p = td->td_proc; #if 0 spin_lock_wr(&p->p_fd->fd_spin); if (p->p_fd->fd_cdir == NULL) { p->p_fd->fd_cdir = rootvnode; vref(rootvnode); } if (p->p_fd->fd_rdir == NULL) { p->p_fd->fd_rdir = rootvnode; vref(rootvnode); } spin_unlock_wr(&p->p_fd->fd_spin); kfree(arg, M_TEMP); #endif } /* * 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 = kmalloc(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 kprintf("%s: no memory for task!\n", __func__); } EVENTHANDLER_DECLARE(mountroot, firmware_mountroot); #endif /* * 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) { int limit = FIRMWARE_MAX; int i; /* current cycle */ lockmgr(&firmware_lock, LK_EXCLUSIVE); /* * Scan the table. limit is set to make sure we make another * full sweep after matching an entry that requires unloading. */ for (i = 0; i < limit; i++) { struct priv_fw *fp; int err; fp = &firmware_table[i % FIRMWARE_MAX]; if (fp->fw.name == NULL || fp->file == NULL || fp->refcnt != 0 || (fp->flags & FW_UNLOAD) == 0) continue; /* * Found an entry. Now: * 1. bump up limit to make sure we make another full round; * 2. clear FW_UNLOAD so we don't try this entry again. * 3. release the lock while trying to unload the module. * 'file' remains set so that the entry cannot be reused * in the meantime (it also means that fp->file will * not change while we release the lock). */ limit = i + FIRMWARE_MAX; /* make another full round */ fp->flags &= ~FW_UNLOAD; /* do not try again */ lockmgr(&firmware_lock, LK_RELEASE); err = linker_release_module(NULL, NULL, fp->file); lockmgr(&firmware_lock, LK_EXCLUSIVE); /* * We rely on the module to call firmware_unregister() * on unload to actually release the entry. * If err = 0 we can drop our reference as the system * accepted it. Otherwise unloading failed (e.g. the * module itself gave an error) so our reference is * still valid. */ if (err == 0) fp->file = NULL; } lockmgr(&firmware_lock, LK_RELEASE); } /* * Module glue. */ static int firmware_modevent(module_t mod, int type, void *unused) { struct priv_fw *fp; int i, err; switch (type) { case MOD_LOAD: TASK_INIT(&firmware_unload_task, 0, unloadentry, NULL); lockinit(&firmware_lock, "firmware table", 0, LK_CANRECURSE); 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, TDPRI_KERN_DAEMON, -1, "firmware taskq"); if (rootvnode != NULL) { /* * Root is already mounted so we won't get an event; * simulate one here. */ #ifdef notyet firmware_mountroot(NULL); #endif } return 0; case MOD_UNLOAD: /* request all autoloaded modules to be released */ lockmgr(&firmware_lock, LK_EXCLUSIVE); for (i = 0; i < FIRMWARE_MAX; i++) { fp = &firmware_table[i]; fp->flags |= FW_UNLOAD; } lockmgr(&firmware_lock, LK_RELEASE); taskqueue_enqueue(firmware_tq, &firmware_unload_task); taskqueue_drain(firmware_tq, &firmware_unload_task); err = 0; for (i = 0; i < FIRMWARE_MAX; i++) { fp = &firmware_table[i]; if (fp->fw.name != NULL) { kprintf("%s: image %p ref %d still active slot %d\n", __func__, fp->fw.name, fp->refcnt, i); err = EINVAL; } } if (err == 0) taskqueue_free(firmware_tq); return err; } return EINVAL; } static moduledata_t firmware_mod = { "firmware", firmware_modevent, NULL }; DECLARE_MODULE(firmware, firmware_mod, SI_SUB_DRIVERS, SI_ORDER_FIRST); MODULE_VERSION(firmware, 1);
