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FreeBSD hs32.drive.ne.jp 9.1-RELEASE FreeBSD 9.1-RELEASE #1: Wed Jan 14 12:18:08 JST 2015 root@hs32.drive.ne.jp:/sys/amd64/compile/hs32 amd64 |
| Current File : //usr/src/sys/kern/subr_firmware.c |
/*-
* 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD: release/9.1.0/sys/kern/subr_firmware.c 238013 2012-07-02 19:19:07Z marius $");
#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/mutex.h>
#include <sys/errno.h>
#include <sys/linker.h>
#include <sys/firmware.h>
#include <sys/priv.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 50
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 mutex protects accesses to the firmware table.
*/
static struct mtx firmware_mtx;
MTX_SYSINIT(firmware, &firmware_mtx, "firmware table", MTX_DEF);
/*
* 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;
mtx_lock(&firmware_mtx);
/*
* Do a lookup to make sure the name is unique or find a free slot.
*/
match = lookup(imagename, &frp);
if (match != NULL) {
mtx_unlock(&firmware_mtx);
printf("%s: image %s already registered!\n",
__func__, imagename);
return NULL;
}
if (frp == NULL) {
mtx_unlock(&firmware_mtx);
printf("%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++;
}
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, 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;
}
mtx_unlock(&firmware_mtx);
return err;
}
static void
loadimage(void *arg, int npending)
{
struct thread *td = curthread;
char *imagename = arg;
struct priv_fw *fp;
linker_file_t result;
int error;
/* synchronize with the thread that dispatched us */
mtx_lock(&firmware_mtx);
mtx_unlock(&firmware_mtx);
if (td->td_proc->p_fd->fd_rdir == NULL) {
printf("%s: root not mounted yet, no way to load image\n",
imagename);
goto done;
}
error = linker_reference_module(imagename, NULL, &result);
if (error != 0) {
printf("%s: could not load firmware image, error %d\n",
imagename, error);
goto done;
}
mtx_lock(&firmware_mtx);
fp = lookup(imagename, NULL);
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);
goto done;
}
fp->file = result; /* record the module identity */
mtx_unlock(&firmware_mtx);
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 thread *td;
struct priv_fw *fp;
mtx_lock(&firmware_mtx);
fp = lookup(imagename, NULL);
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, NULL);
if (fp == NULL) {
mtx_unlock(&firmware_mtx);
return NULL;
}
found: /* common exit point on success */
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 (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)
{
struct thread *td = curthread;
struct proc *p = td->td_proc;
FILEDESC_XLOCK(p->p_fd);
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);
}
FILEDESC_XUNLOCK(p->p_fd);
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)
{
int limit = FIRMWARE_MAX;
int i; /* current cycle */
mtx_lock(&firmware_mtx);
/*
* 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 */
mtx_unlock(&firmware_mtx);
err = linker_release_module(NULL, NULL, fp->file);
mtx_lock(&firmware_mtx);
/*
* 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;
}
mtx_unlock(&firmware_mtx);
}
/*
* 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);
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);
}
return 0;
case MOD_UNLOAD:
/* request all autoloaded modules to be released */
mtx_lock(&firmware_mtx);
for (i = 0; i < FIRMWARE_MAX; i++) {
fp = &firmware_table[i];
fp->flags |= FW_UNLOAD;
}
mtx_unlock(&firmware_mtx);
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);