059d10c7b6
firmware image in the module is registered. Instead, do it when the other image is itself referenced. This allows a module with multiple firmware images to be automatically unloaded when none of the firmware images are in use. Discussed with: jhb@ (on -hackers)
532 lines
15 KiB
C
532 lines
15 KiB
C
/*-
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* Copyright (c) 2005-2008, Sam Leffler <sam@errno.com>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice unmodified, this list of conditions, and the following
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* disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/kernel.h>
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#include <sys/malloc.h>
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#include <sys/queue.h>
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#include <sys/taskqueue.h>
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#include <sys/systm.h>
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#include <sys/lock.h>
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#include <sys/mutex.h>
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#include <sys/errno.h>
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#include <sys/linker.h>
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#include <sys/firmware.h>
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#include <sys/priv.h>
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#include <sys/proc.h>
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#include <sys/module.h>
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#include <sys/eventhandler.h>
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#include <sys/filedesc.h>
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#include <sys/vnode.h>
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/*
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* Loadable firmware support. See sys/sys/firmware.h and firmware(9)
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* form more details on the subsystem.
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*
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* 'struct firmware' is the user-visible part of the firmware table.
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* Additional internal information is stored in a 'struct priv_fw'
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* (currently a static array). A slot is in use if FW_INUSE is true:
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*/
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#define FW_INUSE(p) ((p)->file != NULL || (p)->fw.name != NULL)
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/*
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* fw.name != NULL when an image is registered; file != NULL for
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* autoloaded images whose handling has not been completed.
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*
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* The state of a slot evolves as follows:
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* firmware_register --> fw.name = image_name
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* (autoloaded image) --> file = module reference
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* firmware_unregister --> fw.name = NULL
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* (unloadentry complete) --> file = NULL
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*
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* In order for the above to work, the 'file' field must remain
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* unchanged in firmware_unregister().
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*
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* Images residing in the same module are linked to each other
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* through the 'parent' argument of firmware_register().
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* One image (typically, one with the same name as the module to let
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* the autoloading mechanism work) is considered the parent image for
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* all other images in the same module. Children affect the refcount
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* on the parent image preventing improper unloading of the image itself.
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*/
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struct priv_fw {
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int refcnt; /* reference count */
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/*
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* parent entry, see above. Set on firmware_register(),
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* cleared on firmware_unregister().
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*/
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struct priv_fw *parent;
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int flags; /* record FIRMWARE_UNLOAD requests */
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#define FW_UNLOAD 0x100
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/*
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* 'file' is private info managed by the autoload/unload code.
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* Set at the end of firmware_get(), cleared only in the
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* firmware_unload_task, so the latter can depend on its value even
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* while the lock is not held.
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*/
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linker_file_t file; /* module file, if autoloaded */
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/*
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* 'fw' is the externally visible image information.
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* We do not make it the first field in priv_fw, to avoid the
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* temptation of casting pointers to each other.
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* Use PRIV_FW(fw) to get a pointer to the cointainer of fw.
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* Beware, PRIV_FW does not work for a NULL pointer.
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*/
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struct firmware fw; /* externally visible information */
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};
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/*
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* PRIV_FW returns the pointer to the container of struct firmware *x.
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* Cast to intptr_t to override the 'const' attribute of x
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*/
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#define PRIV_FW(x) ((struct priv_fw *) \
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((intptr_t)(x) - offsetof(struct priv_fw, fw)) )
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/*
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* At the moment we use a static array as backing store for the registry.
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* Should we move to a dynamic structure, keep in mind that we cannot
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* reallocate the array because pointers are held externally.
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* A list may work, though.
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*/
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#define FIRMWARE_MAX 50
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static struct priv_fw firmware_table[FIRMWARE_MAX];
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/*
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* Firmware module operations are handled in a separate task as they
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* might sleep and they require directory context to do i/o.
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*/
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static struct taskqueue *firmware_tq;
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static struct task firmware_unload_task;
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/*
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* This mutex protects accesses to the firmware table.
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*/
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static struct mtx firmware_mtx;
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MTX_SYSINIT(firmware, &firmware_mtx, "firmware table", MTX_DEF);
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/*
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* Helper function to lookup a name.
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* As a side effect, it sets the pointer to a free slot, if any.
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* This way we can concentrate most of the registry scanning in
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* this function, which makes it easier to replace the registry
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* with some other data structure.
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*/
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static struct priv_fw *
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lookup(const char *name, struct priv_fw **empty_slot)
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{
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struct priv_fw *fp = NULL;
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struct priv_fw *dummy;
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int i;
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if (empty_slot == NULL)
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empty_slot = &dummy;
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*empty_slot = NULL;
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for (i = 0; i < FIRMWARE_MAX; i++) {
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fp = &firmware_table[i];
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if (fp->fw.name != NULL && strcasecmp(name, fp->fw.name) == 0)
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break;
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else if (!FW_INUSE(fp))
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*empty_slot = fp;
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}
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return (i < FIRMWARE_MAX ) ? fp : NULL;
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}
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/*
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* Register a firmware image with the specified name. The
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* image name must not already be registered. If this is a
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* subimage then parent refers to a previously registered
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* image that this should be associated with.
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*/
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const struct firmware *
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firmware_register(const char *imagename, const void *data, size_t datasize,
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unsigned int version, const struct firmware *parent)
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{
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struct priv_fw *match, *frp;
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mtx_lock(&firmware_mtx);
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/*
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* Do a lookup to make sure the name is unique or find a free slot.
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*/
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match = lookup(imagename, &frp);
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if (match != NULL) {
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mtx_unlock(&firmware_mtx);
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printf("%s: image %s already registered!\n",
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__func__, imagename);
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return NULL;
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}
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if (frp == NULL) {
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mtx_unlock(&firmware_mtx);
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printf("%s: cannot register image %s, firmware table full!\n",
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__func__, imagename);
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return NULL;
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}
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bzero(frp, sizeof(frp)); /* start from a clean record */
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frp->fw.name = imagename;
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frp->fw.data = data;
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frp->fw.datasize = datasize;
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frp->fw.version = version;
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if (parent != NULL)
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frp->parent = PRIV_FW(parent);
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mtx_unlock(&firmware_mtx);
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if (bootverbose)
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printf("firmware: '%s' version %u: %zu bytes loaded at %p\n",
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imagename, version, datasize, data);
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return &frp->fw;
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}
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/*
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* Unregister/remove a firmware image. If there are outstanding
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* references an error is returned and the image is not removed
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* from the registry.
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*/
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int
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firmware_unregister(const char *imagename)
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{
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struct priv_fw *fp;
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int err;
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mtx_lock(&firmware_mtx);
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fp = lookup(imagename, NULL);
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if (fp == NULL) {
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/*
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* It is ok for the lookup to fail; this can happen
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* when a module is unloaded on last reference and the
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* module unload handler unregister's each of it's
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* firmware images.
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*/
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err = 0;
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} else if (fp->refcnt != 0) { /* cannot unregister */
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err = EBUSY;
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} else {
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linker_file_t x = fp->file; /* save value */
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/*
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* Clear the whole entry with bzero to make sure we
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* do not forget anything. Then restore 'file' which is
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* non-null for autoloaded images.
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*/
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bzero(fp, sizeof(struct priv_fw));
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fp->file = x;
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err = 0;
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}
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mtx_unlock(&firmware_mtx);
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return err;
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}
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static void
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loadimage(void *arg, int npending)
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{
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struct thread *td = curthread;
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char *imagename = arg;
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struct priv_fw *fp;
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linker_file_t result;
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int error;
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/* synchronize with the thread that dispatched us */
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mtx_lock(&firmware_mtx);
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mtx_unlock(&firmware_mtx);
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if (td->td_proc->p_fd->fd_rdir == NULL) {
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printf("%s: root not mounted yet, no way to load image\n",
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imagename);
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goto done;
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}
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error = linker_reference_module(imagename, NULL, &result);
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if (error != 0) {
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printf("%s: could not load firmware image, error %d\n",
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imagename, error);
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goto done;
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}
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mtx_lock(&firmware_mtx);
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fp = lookup(imagename, NULL);
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if (fp == NULL || fp->file != NULL) {
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mtx_unlock(&firmware_mtx);
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if (fp == NULL)
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printf("%s: firmware image loaded, "
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"but did not register\n", imagename);
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(void) linker_release_module(imagename, NULL, NULL);
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goto done;
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}
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fp->file = result; /* record the module identity */
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mtx_unlock(&firmware_mtx);
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done:
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wakeup_one(imagename); /* we're done */
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}
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/*
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* Lookup and potentially load the specified firmware image.
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* If the firmware is not found in the registry, try to load a kernel
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* module named as the image name.
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* If the firmware is located, a reference is returned. The caller must
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* release this reference for the image to be eligible for removal/unload.
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*/
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const struct firmware *
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firmware_get(const char *imagename)
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{
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struct task fwload_task;
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struct thread *td;
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struct priv_fw *fp;
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mtx_lock(&firmware_mtx);
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fp = lookup(imagename, NULL);
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if (fp != NULL)
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goto found;
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/*
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* Image not present, try to load the module holding it.
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*/
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td = curthread;
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if (priv_check(td, PRIV_FIRMWARE_LOAD) != 0 ||
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securelevel_gt(td->td_ucred, 0) != 0) {
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mtx_unlock(&firmware_mtx);
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printf("%s: insufficient privileges to "
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"load firmware image %s\n", __func__, imagename);
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return NULL;
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}
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/*
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* Defer load to a thread with known context. linker_reference_module
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* may do filesystem i/o which requires root & current dirs, etc.
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* Also we must not hold any mtx's over this call which is problematic.
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*/
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if (!cold) {
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TASK_INIT(&fwload_task, 0, loadimage, __DECONST(void *,
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imagename));
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taskqueue_enqueue(firmware_tq, &fwload_task);
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msleep(__DECONST(void *, imagename), &firmware_mtx, 0,
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"fwload", 0);
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}
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/*
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* After attempting to load the module, see if the image is registered.
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*/
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fp = lookup(imagename, NULL);
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if (fp == NULL) {
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mtx_unlock(&firmware_mtx);
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return NULL;
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}
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found: /* common exit point on success */
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if (fp->refcnt == 0 && fp->parent != NULL)
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fp->parent->refcnt++;
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fp->refcnt++;
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mtx_unlock(&firmware_mtx);
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return &fp->fw;
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}
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/*
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* Release a reference to a firmware image returned by firmware_get.
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* The caller may specify, with the FIRMWARE_UNLOAD flag, its desire
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* to release the resource, but the flag is only advisory.
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*
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* If this is the last reference to the firmware image, and this is an
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* autoloaded module, wake up the firmware_unload_task to figure out
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* what to do with the associated module.
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*/
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void
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firmware_put(const struct firmware *p, int flags)
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{
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struct priv_fw *fp = PRIV_FW(p);
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mtx_lock(&firmware_mtx);
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fp->refcnt--;
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if (fp->refcnt == 0) {
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if (fp->parent != NULL)
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fp->parent->refcnt--;
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if (flags & FIRMWARE_UNLOAD)
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fp->flags |= FW_UNLOAD;
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if (fp->file)
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taskqueue_enqueue(firmware_tq, &firmware_unload_task);
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}
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mtx_unlock(&firmware_mtx);
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}
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/*
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* Setup directory state for the firmware_tq thread so we can do i/o.
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*/
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static void
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set_rootvnode(void *arg, int npending)
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{
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struct thread *td = curthread;
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struct proc *p = td->td_proc;
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FILEDESC_XLOCK(p->p_fd);
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if (p->p_fd->fd_cdir == NULL) {
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p->p_fd->fd_cdir = rootvnode;
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VREF(rootvnode);
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}
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if (p->p_fd->fd_rdir == NULL) {
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p->p_fd->fd_rdir = rootvnode;
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VREF(rootvnode);
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}
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FILEDESC_XUNLOCK(p->p_fd);
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free(arg, M_TEMP);
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}
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/*
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* Event handler called on mounting of /; bounce a task
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* into the task queue thread to setup it's directories.
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*/
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static void
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firmware_mountroot(void *arg)
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{
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struct task *setroot_task;
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setroot_task = malloc(sizeof(struct task), M_TEMP, M_NOWAIT);
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if (setroot_task != NULL) {
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TASK_INIT(setroot_task, 0, set_rootvnode, setroot_task);
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taskqueue_enqueue(firmware_tq, setroot_task);
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} else
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printf("%s: no memory for task!\n", __func__);
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}
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EVENTHANDLER_DEFINE(mountroot, firmware_mountroot, NULL, 0);
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/*
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* The body of the task in charge of unloading autoloaded modules
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* that are not needed anymore.
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* Images can be cross-linked so we may need to make multiple passes,
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* but the time we spend in the loop is bounded because we clear entries
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* as we touch them.
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*/
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static void
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unloadentry(void *unused1, int unused2)
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{
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int limit = FIRMWARE_MAX;
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int i; /* current cycle */
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mtx_lock(&firmware_mtx);
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/*
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* Scan the table. limit is set to make sure we make another
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* full sweep after matching an entry that requires unloading.
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*/
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for (i = 0; i < limit; i++) {
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struct priv_fw *fp;
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int err;
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fp = &firmware_table[i % FIRMWARE_MAX];
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if (fp->fw.name == NULL || fp->file == NULL ||
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fp->refcnt != 0 || (fp->flags & FW_UNLOAD) == 0)
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continue;
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/*
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* Found an entry. Now:
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* 1. bump up limit to make sure we make another full round;
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* 2. clear FW_UNLOAD so we don't try this entry again.
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* 3. release the lock while trying to unload the module.
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* 'file' remains set so that the entry cannot be reused
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* in the meantime (it also means that fp->file will
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* not change while we release the lock).
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*/
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limit = i + FIRMWARE_MAX; /* make another full round */
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fp->flags &= ~FW_UNLOAD; /* do not try again */
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mtx_unlock(&firmware_mtx);
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err = linker_release_module(NULL, NULL, fp->file);
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mtx_lock(&firmware_mtx);
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/*
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* We rely on the module to call firmware_unregister()
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* on unload to actually release the entry.
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* If err = 0 we can drop our reference as the system
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* accepted it. Otherwise unloading failed (e.g. the
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* module itself gave an error) so our reference is
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* still valid.
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*/
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if (err == 0)
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fp->file = NULL;
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}
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mtx_unlock(&firmware_mtx);
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}
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/*
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* Module glue.
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*/
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static int
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firmware_modevent(module_t mod, int type, void *unused)
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{
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struct priv_fw *fp;
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int i, err;
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switch (type) {
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case MOD_LOAD:
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TASK_INIT(&firmware_unload_task, 0, unloadentry, NULL);
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firmware_tq = taskqueue_create("taskqueue_firmware", M_WAITOK,
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taskqueue_thread_enqueue, &firmware_tq);
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/* NB: use our own loop routine that sets up context */
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(void) taskqueue_start_threads(&firmware_tq, 1, PWAIT,
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"firmware taskq");
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if (rootvnode != NULL) {
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/*
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* Root is already mounted so we won't get an event;
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* simulate one here.
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*/
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firmware_mountroot(NULL);
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}
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return 0;
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case MOD_UNLOAD:
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/* request all autoloaded modules to be released */
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mtx_lock(&firmware_mtx);
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for (i = 0; i < FIRMWARE_MAX; i++) {
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fp = &firmware_table[i];
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fp->flags |= FW_UNLOAD;
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}
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mtx_unlock(&firmware_mtx);
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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) {
|
|
printf("%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);
|