1 // SPDX-License-Identifier: GPL-2.0
3 #include <linux/types.h>
4 #include <linux/kconfig.h>
5 #include <linux/list.h>
6 #include <linux/slab.h>
7 #include <linux/security.h>
8 #include <linux/highmem.h>
10 #include <linux/sysctl.h>
11 #include <linux/vmalloc.h>
17 * firmware fallback mechanism
20 extern struct firmware_fallback_config fw_fallback_config;
22 /* These getters are vetted to use int properly */
23 static inline int __firmware_loading_timeout(void)
25 return fw_fallback_config.loading_timeout;
28 /* These setters are vetted to use int properly */
29 static void __fw_fallback_set_timeout(int timeout)
31 fw_fallback_config.loading_timeout = timeout;
35 * use small loading timeout for caching devices' firmware because all these
36 * firmware images have been loaded successfully at lease once, also system is
37 * ready for completing firmware loading now. The maximum size of firmware in
38 * current distributions is about 2M bytes, so 10 secs should be enough.
40 void fw_fallback_set_cache_timeout(void)
42 fw_fallback_config.old_timeout = __firmware_loading_timeout();
43 __fw_fallback_set_timeout(10);
46 /* Restores the timeout to the value last configured during normal operation */
47 void fw_fallback_set_default_timeout(void)
49 __fw_fallback_set_timeout(fw_fallback_config.old_timeout);
52 static long firmware_loading_timeout(void)
54 return __firmware_loading_timeout() > 0 ?
55 __firmware_loading_timeout() * HZ : MAX_JIFFY_OFFSET;
58 static inline bool fw_sysfs_done(struct fw_priv *fw_priv)
60 return __fw_state_check(fw_priv, FW_STATUS_DONE);
63 static inline bool fw_sysfs_loading(struct fw_priv *fw_priv)
65 return __fw_state_check(fw_priv, FW_STATUS_LOADING);
68 static inline int fw_sysfs_wait_timeout(struct fw_priv *fw_priv, long timeout)
70 return __fw_state_wait_common(fw_priv, timeout);
76 struct fw_priv *fw_priv;
80 static struct fw_sysfs *to_fw_sysfs(struct device *dev)
82 return container_of(dev, struct fw_sysfs, dev);
85 static void __fw_load_abort(struct fw_priv *fw_priv)
88 * There is a small window in which user can write to 'loading'
89 * between loading done/aborted and disappearance of 'loading'
91 if (fw_state_is_aborted(fw_priv) || fw_sysfs_done(fw_priv))
94 fw_state_aborted(fw_priv);
97 static void fw_load_abort(struct fw_sysfs *fw_sysfs)
99 struct fw_priv *fw_priv = fw_sysfs->fw_priv;
101 __fw_load_abort(fw_priv);
104 static LIST_HEAD(pending_fw_head);
106 void kill_pending_fw_fallback_reqs(bool only_kill_custom)
108 struct fw_priv *fw_priv;
109 struct fw_priv *next;
111 mutex_lock(&fw_lock);
112 list_for_each_entry_safe(fw_priv, next, &pending_fw_head,
114 if (!fw_priv->need_uevent || !only_kill_custom)
115 __fw_load_abort(fw_priv);
117 mutex_unlock(&fw_lock);
120 static ssize_t timeout_show(struct class *class, struct class_attribute *attr,
123 return sprintf(buf, "%d\n", __firmware_loading_timeout());
127 * firmware_timeout_store() - set number of seconds to wait for firmware
128 * @class: device class pointer
129 * @attr: device attribute pointer
130 * @buf: buffer to scan for timeout value
131 * @count: number of bytes in @buf
133 * Sets the number of seconds to wait for the firmware. Once
134 * this expires an error will be returned to the driver and no
135 * firmware will be provided.
137 * Note: zero means 'wait forever'.
139 static ssize_t timeout_store(struct class *class, struct class_attribute *attr,
140 const char *buf, size_t count)
142 int tmp_loading_timeout = simple_strtol(buf, NULL, 10);
144 if (tmp_loading_timeout < 0)
145 tmp_loading_timeout = 0;
147 __fw_fallback_set_timeout(tmp_loading_timeout);
151 static CLASS_ATTR_RW(timeout);
153 static struct attribute *firmware_class_attrs[] = {
154 &class_attr_timeout.attr,
157 ATTRIBUTE_GROUPS(firmware_class);
159 static void fw_dev_release(struct device *dev)
161 struct fw_sysfs *fw_sysfs = to_fw_sysfs(dev);
166 static int do_firmware_uevent(struct fw_sysfs *fw_sysfs, struct kobj_uevent_env *env)
168 if (add_uevent_var(env, "FIRMWARE=%s", fw_sysfs->fw_priv->fw_name))
170 if (add_uevent_var(env, "TIMEOUT=%i", __firmware_loading_timeout()))
172 if (add_uevent_var(env, "ASYNC=%d", fw_sysfs->nowait))
178 static int firmware_uevent(struct device *dev, struct kobj_uevent_env *env)
180 struct fw_sysfs *fw_sysfs = to_fw_sysfs(dev);
183 mutex_lock(&fw_lock);
184 if (fw_sysfs->fw_priv)
185 err = do_firmware_uevent(fw_sysfs, env);
186 mutex_unlock(&fw_lock);
190 static struct class firmware_class = {
192 .class_groups = firmware_class_groups,
193 .dev_uevent = firmware_uevent,
194 .dev_release = fw_dev_release,
197 int register_sysfs_loader(void)
199 return class_register(&firmware_class);
202 void unregister_sysfs_loader(void)
204 class_unregister(&firmware_class);
207 static ssize_t firmware_loading_show(struct device *dev,
208 struct device_attribute *attr, char *buf)
210 struct fw_sysfs *fw_sysfs = to_fw_sysfs(dev);
213 mutex_lock(&fw_lock);
214 if (fw_sysfs->fw_priv)
215 loading = fw_sysfs_loading(fw_sysfs->fw_priv);
216 mutex_unlock(&fw_lock);
218 return sprintf(buf, "%d\n", loading);
221 /* one pages buffer should be mapped/unmapped only once */
222 static int map_fw_priv_pages(struct fw_priv *fw_priv)
224 if (!fw_priv->is_paged_buf)
227 vunmap(fw_priv->data);
228 fw_priv->data = vmap(fw_priv->pages, fw_priv->nr_pages, 0,
236 * firmware_loading_store() - set value in the 'loading' control file
237 * @dev: device pointer
238 * @attr: device attribute pointer
239 * @buf: buffer to scan for loading control value
240 * @count: number of bytes in @buf
242 * The relevant values are:
244 * 1: Start a load, discarding any previous partial load.
245 * 0: Conclude the load and hand the data to the driver code.
246 * -1: Conclude the load with an error and discard any written data.
248 static ssize_t firmware_loading_store(struct device *dev,
249 struct device_attribute *attr,
250 const char *buf, size_t count)
252 struct fw_sysfs *fw_sysfs = to_fw_sysfs(dev);
253 struct fw_priv *fw_priv;
254 ssize_t written = count;
255 int loading = simple_strtol(buf, NULL, 10);
258 mutex_lock(&fw_lock);
259 fw_priv = fw_sysfs->fw_priv;
260 if (fw_state_is_aborted(fw_priv))
265 /* discarding any previous partial load */
266 if (!fw_sysfs_done(fw_priv)) {
267 for (i = 0; i < fw_priv->nr_pages; i++)
268 __free_page(fw_priv->pages[i]);
269 vfree(fw_priv->pages);
270 fw_priv->pages = NULL;
271 fw_priv->page_array_size = 0;
272 fw_priv->nr_pages = 0;
273 fw_state_start(fw_priv);
277 if (fw_sysfs_loading(fw_priv)) {
281 * Several loading requests may be pending on
282 * one same firmware buf, so let all requests
283 * see the mapped 'buf->data' once the loading
286 rc = map_fw_priv_pages(fw_priv);
288 dev_err(dev, "%s: map pages failed\n",
291 rc = security_kernel_post_read_file(NULL,
292 fw_priv->data, fw_priv->size,
296 * Same logic as fw_load_abort, only the DONE bit
297 * is ignored and we set ABORT only on failure.
300 fw_state_aborted(fw_priv);
303 fw_state_done(fw_priv);
309 dev_err(dev, "%s: unexpected value (%d)\n", __func__, loading);
312 fw_load_abort(fw_sysfs);
316 mutex_unlock(&fw_lock);
320 static DEVICE_ATTR(loading, 0644, firmware_loading_show, firmware_loading_store);
322 static void firmware_rw_data(struct fw_priv *fw_priv, char *buffer,
323 loff_t offset, size_t count, bool read)
326 memcpy(buffer, fw_priv->data + offset, count);
328 memcpy(fw_priv->data + offset, buffer, count);
331 static void firmware_rw(struct fw_priv *fw_priv, char *buffer,
332 loff_t offset, size_t count, bool read)
336 int page_nr = offset >> PAGE_SHIFT;
337 int page_ofs = offset & (PAGE_SIZE-1);
338 int page_cnt = min_t(size_t, PAGE_SIZE - page_ofs, count);
340 page_data = kmap(fw_priv->pages[page_nr]);
343 memcpy(buffer, page_data + page_ofs, page_cnt);
345 memcpy(page_data + page_ofs, buffer, page_cnt);
347 kunmap(fw_priv->pages[page_nr]);
354 static ssize_t firmware_data_read(struct file *filp, struct kobject *kobj,
355 struct bin_attribute *bin_attr,
356 char *buffer, loff_t offset, size_t count)
358 struct device *dev = kobj_to_dev(kobj);
359 struct fw_sysfs *fw_sysfs = to_fw_sysfs(dev);
360 struct fw_priv *fw_priv;
363 mutex_lock(&fw_lock);
364 fw_priv = fw_sysfs->fw_priv;
365 if (!fw_priv || fw_sysfs_done(fw_priv)) {
369 if (offset > fw_priv->size) {
373 if (count > fw_priv->size - offset)
374 count = fw_priv->size - offset;
379 firmware_rw_data(fw_priv, buffer, offset, count, true);
381 firmware_rw(fw_priv, buffer, offset, count, true);
384 mutex_unlock(&fw_lock);
388 static int fw_realloc_pages(struct fw_sysfs *fw_sysfs, int min_size)
390 struct fw_priv *fw_priv= fw_sysfs->fw_priv;
391 int pages_needed = PAGE_ALIGN(min_size) >> PAGE_SHIFT;
393 /* If the array of pages is too small, grow it... */
394 if (fw_priv->page_array_size < pages_needed) {
395 int new_array_size = max(pages_needed,
396 fw_priv->page_array_size * 2);
397 struct page **new_pages;
399 new_pages = vmalloc(array_size(new_array_size, sizeof(void *)));
401 fw_load_abort(fw_sysfs);
404 memcpy(new_pages, fw_priv->pages,
405 fw_priv->page_array_size * sizeof(void *));
406 memset(&new_pages[fw_priv->page_array_size], 0, sizeof(void *) *
407 (new_array_size - fw_priv->page_array_size));
408 vfree(fw_priv->pages);
409 fw_priv->pages = new_pages;
410 fw_priv->page_array_size = new_array_size;
413 while (fw_priv->nr_pages < pages_needed) {
414 fw_priv->pages[fw_priv->nr_pages] =
415 alloc_page(GFP_KERNEL | __GFP_HIGHMEM);
417 if (!fw_priv->pages[fw_priv->nr_pages]) {
418 fw_load_abort(fw_sysfs);
427 * firmware_data_write() - write method for firmware
428 * @filp: open sysfs file
429 * @kobj: kobject for the device
430 * @bin_attr: bin_attr structure
431 * @buffer: buffer being written
432 * @offset: buffer offset for write in total data store area
433 * @count: buffer size
435 * Data written to the 'data' attribute will be later handed to
436 * the driver as a firmware image.
438 static ssize_t firmware_data_write(struct file *filp, struct kobject *kobj,
439 struct bin_attribute *bin_attr,
440 char *buffer, loff_t offset, size_t count)
442 struct device *dev = kobj_to_dev(kobj);
443 struct fw_sysfs *fw_sysfs = to_fw_sysfs(dev);
444 struct fw_priv *fw_priv;
447 if (!capable(CAP_SYS_RAWIO))
450 mutex_lock(&fw_lock);
451 fw_priv = fw_sysfs->fw_priv;
452 if (!fw_priv || fw_sysfs_done(fw_priv)) {
458 if (offset + count > fw_priv->allocated_size) {
462 firmware_rw_data(fw_priv, buffer, offset, count, false);
465 retval = fw_realloc_pages(fw_sysfs, offset + count);
470 firmware_rw(fw_priv, buffer, offset, count, false);
473 fw_priv->size = max_t(size_t, offset + count, fw_priv->size);
475 mutex_unlock(&fw_lock);
479 static struct bin_attribute firmware_attr_data = {
480 .attr = { .name = "data", .mode = 0644 },
482 .read = firmware_data_read,
483 .write = firmware_data_write,
486 static struct attribute *fw_dev_attrs[] = {
487 &dev_attr_loading.attr,
491 static struct bin_attribute *fw_dev_bin_attrs[] = {
496 static const struct attribute_group fw_dev_attr_group = {
497 .attrs = fw_dev_attrs,
498 .bin_attrs = fw_dev_bin_attrs,
501 static const struct attribute_group *fw_dev_attr_groups[] = {
506 static struct fw_sysfs *
507 fw_create_instance(struct firmware *firmware, const char *fw_name,
508 struct device *device, enum fw_opt opt_flags)
510 struct fw_sysfs *fw_sysfs;
511 struct device *f_dev;
513 fw_sysfs = kzalloc(sizeof(*fw_sysfs), GFP_KERNEL);
515 fw_sysfs = ERR_PTR(-ENOMEM);
519 fw_sysfs->nowait = !!(opt_flags & FW_OPT_NOWAIT);
520 fw_sysfs->fw = firmware;
521 f_dev = &fw_sysfs->dev;
523 device_initialize(f_dev);
524 dev_set_name(f_dev, "%s", fw_name);
525 f_dev->parent = device;
526 f_dev->class = &firmware_class;
527 f_dev->groups = fw_dev_attr_groups;
533 * fw_load_sysfs_fallback() - load a firmware via the sysfs fallback mechanism
534 * @fw_sysfs: firmware sysfs information for the firmware to load
535 * @opt_flags: flags of options, FW_OPT_*
536 * @timeout: timeout to wait for the load
538 * In charge of constructing a sysfs fallback interface for firmware loading.
540 static int fw_load_sysfs_fallback(struct fw_sysfs *fw_sysfs,
541 enum fw_opt opt_flags, long timeout)
544 struct device *f_dev = &fw_sysfs->dev;
545 struct fw_priv *fw_priv = fw_sysfs->fw_priv;
547 /* fall back on userspace loading */
549 fw_priv->is_paged_buf = true;
551 dev_set_uevent_suppress(f_dev, true);
553 retval = device_add(f_dev);
555 dev_err(f_dev, "%s: device_register failed\n", __func__);
559 mutex_lock(&fw_lock);
560 if (fw_state_is_aborted(fw_priv)) {
561 mutex_unlock(&fw_lock);
565 list_add(&fw_priv->pending_list, &pending_fw_head);
566 mutex_unlock(&fw_lock);
568 if (opt_flags & FW_OPT_UEVENT) {
569 fw_priv->need_uevent = true;
570 dev_set_uevent_suppress(f_dev, false);
571 dev_dbg(f_dev, "firmware: requesting %s\n", fw_priv->fw_name);
572 kobject_uevent(&fw_sysfs->dev.kobj, KOBJ_ADD);
574 timeout = MAX_JIFFY_OFFSET;
577 retval = fw_sysfs_wait_timeout(fw_priv, timeout);
578 if (retval < 0 && retval != -ENOENT) {
579 mutex_lock(&fw_lock);
580 fw_load_abort(fw_sysfs);
581 mutex_unlock(&fw_lock);
584 if (fw_state_is_aborted(fw_priv)) {
585 if (retval == -ERESTARTSYS)
587 } else if (fw_priv->is_paged_buf && !fw_priv->data)
597 static int fw_load_from_user_helper(struct firmware *firmware,
598 const char *name, struct device *device,
599 enum fw_opt opt_flags)
601 struct fw_sysfs *fw_sysfs;
605 timeout = is_nonfree_firmware(name) ? 1 : firmware_loading_timeout();
606 if (opt_flags & FW_OPT_NOWAIT) {
607 timeout = usermodehelper_read_lock_wait(timeout);
609 dev_dbg(device, "firmware: %s loading timed out\n",
614 ret = usermodehelper_read_trylock();
616 dev_err(device, "firmware: %s will not be loaded\n",
622 fw_sysfs = fw_create_instance(firmware, name, device, opt_flags);
623 if (IS_ERR(fw_sysfs)) {
624 ret = PTR_ERR(fw_sysfs);
628 fw_sysfs->fw_priv = firmware->priv;
629 ret = fw_load_sysfs_fallback(fw_sysfs, opt_flags, timeout);
632 ret = assign_fw(firmware, device, opt_flags);
635 usermodehelper_read_unlock();
640 static bool fw_force_sysfs_fallback(enum fw_opt opt_flags)
642 if (fw_fallback_config.force_sysfs_fallback)
644 if (!(opt_flags & FW_OPT_USERHELPER))
649 static bool fw_run_sysfs_fallback(enum fw_opt opt_flags)
653 if (fw_fallback_config.ignore_sysfs_fallback) {
654 pr_info_once("Ignoring firmware sysfs fallback due to sysctl knob\n");
658 if ((opt_flags & FW_OPT_NOFALLBACK))
661 /* Also permit LSMs and IMA to fail firmware sysfs fallback */
662 ret = security_kernel_load_data(LOADING_FIRMWARE);
666 return fw_force_sysfs_fallback(opt_flags);
670 * firmware_fallback_sysfs() - use the fallback mechanism to find firmware
671 * @fw: pointer to firmware image
672 * @name: name of firmware file to look for
673 * @device: device for which firmware is being loaded
674 * @opt_flags: options to control firmware loading behaviour
675 * @ret: return value from direct lookup which triggered the fallback mechanism
677 * This function is called if direct lookup for the firmware failed, it enables
678 * a fallback mechanism through userspace by exposing a sysfs loading
679 * interface. Userspace is in charge of loading the firmware through the syfs
680 * loading interface. This syfs fallback mechanism may be disabled completely
681 * on a system by setting the proc sysctl value ignore_sysfs_fallback to true.
682 * If this false we check if the internal API caller set the @FW_OPT_NOFALLBACK
683 * flag, if so it would also disable the fallback mechanism. A system may want
684 * to enfoce the sysfs fallback mechanism at all times, it can do this by
685 * setting ignore_sysfs_fallback to false and force_sysfs_fallback to true.
686 * Enabling force_sysfs_fallback is functionally equivalent to build a kernel
687 * with CONFIG_FW_LOADER_USER_HELPER_FALLBACK.
689 int firmware_fallback_sysfs(struct firmware *fw, const char *name,
690 struct device *device,
691 enum fw_opt opt_flags,
694 if (!fw_run_sysfs_fallback(opt_flags))
697 if (!(opt_flags & FW_OPT_NO_WARN))
698 dev_warn(device, "Falling back to syfs fallback for: %s\n",
701 dev_dbg(device, "Falling back to sysfs fallback for: %s\n",
703 return fw_load_from_user_helper(fw, name, device, opt_flags);