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>
12 #include <linux/module.h>
18 * firmware fallback mechanism
21 MODULE_IMPORT_NS(FIRMWARE_LOADER_PRIVATE);
23 extern struct firmware_fallback_config fw_fallback_config;
25 /* These getters are vetted to use int properly */
26 static inline int __firmware_loading_timeout(void)
28 return fw_fallback_config.loading_timeout;
31 /* These setters are vetted to use int properly */
32 static void __fw_fallback_set_timeout(int timeout)
34 fw_fallback_config.loading_timeout = timeout;
38 * use small loading timeout for caching devices' firmware because all these
39 * firmware images have been loaded successfully at lease once, also system is
40 * ready for completing firmware loading now. The maximum size of firmware in
41 * current distributions is about 2M bytes, so 10 secs should be enough.
43 void fw_fallback_set_cache_timeout(void)
45 fw_fallback_config.old_timeout = __firmware_loading_timeout();
46 __fw_fallback_set_timeout(10);
49 /* Restores the timeout to the value last configured during normal operation */
50 void fw_fallback_set_default_timeout(void)
52 __fw_fallback_set_timeout(fw_fallback_config.old_timeout);
55 static long firmware_loading_timeout(void)
57 return __firmware_loading_timeout() > 0 ?
58 __firmware_loading_timeout() * HZ : MAX_JIFFY_OFFSET;
61 static inline bool fw_sysfs_done(struct fw_priv *fw_priv)
63 return __fw_state_check(fw_priv, FW_STATUS_DONE);
66 static inline bool fw_sysfs_loading(struct fw_priv *fw_priv)
68 return __fw_state_check(fw_priv, FW_STATUS_LOADING);
71 static inline int fw_sysfs_wait_timeout(struct fw_priv *fw_priv, long timeout)
73 return __fw_state_wait_common(fw_priv, timeout);
79 struct fw_priv *fw_priv;
83 static struct fw_sysfs *to_fw_sysfs(struct device *dev)
85 return container_of(dev, struct fw_sysfs, dev);
88 static void __fw_load_abort(struct fw_priv *fw_priv)
91 * There is a small window in which user can write to 'loading'
92 * between loading done/aborted and disappearance of 'loading'
94 if (fw_state_is_aborted(fw_priv) || fw_sysfs_done(fw_priv))
97 fw_state_aborted(fw_priv);
100 static void fw_load_abort(struct fw_sysfs *fw_sysfs)
102 struct fw_priv *fw_priv = fw_sysfs->fw_priv;
104 __fw_load_abort(fw_priv);
107 static LIST_HEAD(pending_fw_head);
109 void kill_pending_fw_fallback_reqs(bool only_kill_custom)
111 struct fw_priv *fw_priv;
112 struct fw_priv *next;
114 mutex_lock(&fw_lock);
115 list_for_each_entry_safe(fw_priv, next, &pending_fw_head,
117 if (!fw_priv->need_uevent || !only_kill_custom)
118 __fw_load_abort(fw_priv);
120 mutex_unlock(&fw_lock);
123 static ssize_t timeout_show(struct class *class, struct class_attribute *attr,
126 return sysfs_emit(buf, "%d\n", __firmware_loading_timeout());
130 * timeout_store() - set number of seconds to wait for firmware
131 * @class: device class pointer
132 * @attr: device attribute pointer
133 * @buf: buffer to scan for timeout value
134 * @count: number of bytes in @buf
136 * Sets the number of seconds to wait for the firmware. Once
137 * this expires an error will be returned to the driver and no
138 * firmware will be provided.
140 * Note: zero means 'wait forever'.
142 static ssize_t timeout_store(struct class *class, struct class_attribute *attr,
143 const char *buf, size_t count)
145 int tmp_loading_timeout = simple_strtol(buf, NULL, 10);
147 if (tmp_loading_timeout < 0)
148 tmp_loading_timeout = 0;
150 __fw_fallback_set_timeout(tmp_loading_timeout);
154 static CLASS_ATTR_RW(timeout);
156 static struct attribute *firmware_class_attrs[] = {
157 &class_attr_timeout.attr,
160 ATTRIBUTE_GROUPS(firmware_class);
162 static void fw_dev_release(struct device *dev)
164 struct fw_sysfs *fw_sysfs = to_fw_sysfs(dev);
169 static int do_firmware_uevent(struct fw_sysfs *fw_sysfs, struct kobj_uevent_env *env)
171 if (add_uevent_var(env, "FIRMWARE=%s", fw_sysfs->fw_priv->fw_name))
173 if (add_uevent_var(env, "TIMEOUT=%i", __firmware_loading_timeout()))
175 if (add_uevent_var(env, "ASYNC=%d", fw_sysfs->nowait))
181 static int firmware_uevent(struct device *dev, struct kobj_uevent_env *env)
183 struct fw_sysfs *fw_sysfs = to_fw_sysfs(dev);
186 mutex_lock(&fw_lock);
187 if (fw_sysfs->fw_priv)
188 err = do_firmware_uevent(fw_sysfs, env);
189 mutex_unlock(&fw_lock);
193 static struct class firmware_class = {
195 .class_groups = firmware_class_groups,
196 .dev_uevent = firmware_uevent,
197 .dev_release = fw_dev_release,
200 int register_sysfs_loader(void)
202 int ret = class_register(&firmware_class);
206 return register_firmware_config_sysctl();
209 void unregister_sysfs_loader(void)
211 unregister_firmware_config_sysctl();
212 class_unregister(&firmware_class);
215 static ssize_t firmware_loading_show(struct device *dev,
216 struct device_attribute *attr, char *buf)
218 struct fw_sysfs *fw_sysfs = to_fw_sysfs(dev);
221 mutex_lock(&fw_lock);
222 if (fw_sysfs->fw_priv)
223 loading = fw_sysfs_loading(fw_sysfs->fw_priv);
224 mutex_unlock(&fw_lock);
226 return sysfs_emit(buf, "%d\n", loading);
230 * firmware_loading_store() - set value in the 'loading' control file
231 * @dev: device pointer
232 * @attr: device attribute pointer
233 * @buf: buffer to scan for loading control value
234 * @count: number of bytes in @buf
236 * The relevant values are:
238 * 1: Start a load, discarding any previous partial load.
239 * 0: Conclude the load and hand the data to the driver code.
240 * -1: Conclude the load with an error and discard any written data.
242 static ssize_t firmware_loading_store(struct device *dev,
243 struct device_attribute *attr,
244 const char *buf, size_t count)
246 struct fw_sysfs *fw_sysfs = to_fw_sysfs(dev);
247 struct fw_priv *fw_priv;
248 ssize_t written = count;
249 int loading = simple_strtol(buf, NULL, 10);
251 mutex_lock(&fw_lock);
252 fw_priv = fw_sysfs->fw_priv;
253 if (fw_state_is_aborted(fw_priv))
258 /* discarding any previous partial load */
259 if (!fw_sysfs_done(fw_priv)) {
260 fw_free_paged_buf(fw_priv);
261 fw_state_start(fw_priv);
265 if (fw_sysfs_loading(fw_priv)) {
269 * Several loading requests may be pending on
270 * one same firmware buf, so let all requests
271 * see the mapped 'buf->data' once the loading
274 rc = fw_map_paged_buf(fw_priv);
276 dev_err(dev, "%s: map pages failed\n",
279 rc = security_kernel_post_load_data(fw_priv->data,
281 LOADING_FIRMWARE, "blob");
284 * Same logic as fw_load_abort, only the DONE bit
285 * is ignored and we set ABORT only on failure.
288 fw_state_aborted(fw_priv);
291 fw_state_done(fw_priv);
297 dev_err(dev, "%s: unexpected value (%d)\n", __func__, loading);
300 fw_load_abort(fw_sysfs);
304 mutex_unlock(&fw_lock);
308 static DEVICE_ATTR(loading, 0644, firmware_loading_show, firmware_loading_store);
310 static void firmware_rw_data(struct fw_priv *fw_priv, char *buffer,
311 loff_t offset, size_t count, bool read)
314 memcpy(buffer, fw_priv->data + offset, count);
316 memcpy(fw_priv->data + offset, buffer, count);
319 static void firmware_rw(struct fw_priv *fw_priv, char *buffer,
320 loff_t offset, size_t count, bool read)
324 int page_nr = offset >> PAGE_SHIFT;
325 int page_ofs = offset & (PAGE_SIZE-1);
326 int page_cnt = min_t(size_t, PAGE_SIZE - page_ofs, count);
328 page_data = kmap(fw_priv->pages[page_nr]);
331 memcpy(buffer, page_data + page_ofs, page_cnt);
333 memcpy(page_data + page_ofs, buffer, page_cnt);
335 kunmap(fw_priv->pages[page_nr]);
342 static ssize_t firmware_data_read(struct file *filp, struct kobject *kobj,
343 struct bin_attribute *bin_attr,
344 char *buffer, loff_t offset, size_t count)
346 struct device *dev = kobj_to_dev(kobj);
347 struct fw_sysfs *fw_sysfs = to_fw_sysfs(dev);
348 struct fw_priv *fw_priv;
351 mutex_lock(&fw_lock);
352 fw_priv = fw_sysfs->fw_priv;
353 if (!fw_priv || fw_sysfs_done(fw_priv)) {
357 if (offset > fw_priv->size) {
361 if (count > fw_priv->size - offset)
362 count = fw_priv->size - offset;
367 firmware_rw_data(fw_priv, buffer, offset, count, true);
369 firmware_rw(fw_priv, buffer, offset, count, true);
372 mutex_unlock(&fw_lock);
376 static int fw_realloc_pages(struct fw_sysfs *fw_sysfs, int min_size)
380 err = fw_grow_paged_buf(fw_sysfs->fw_priv,
381 PAGE_ALIGN(min_size) >> PAGE_SHIFT);
383 fw_load_abort(fw_sysfs);
388 * firmware_data_write() - write method for firmware
389 * @filp: open sysfs file
390 * @kobj: kobject for the device
391 * @bin_attr: bin_attr structure
392 * @buffer: buffer being written
393 * @offset: buffer offset for write in total data store area
394 * @count: buffer size
396 * Data written to the 'data' attribute will be later handed to
397 * the driver as a firmware image.
399 static ssize_t firmware_data_write(struct file *filp, struct kobject *kobj,
400 struct bin_attribute *bin_attr,
401 char *buffer, loff_t offset, size_t count)
403 struct device *dev = kobj_to_dev(kobj);
404 struct fw_sysfs *fw_sysfs = to_fw_sysfs(dev);
405 struct fw_priv *fw_priv;
408 if (!capable(CAP_SYS_RAWIO))
411 mutex_lock(&fw_lock);
412 fw_priv = fw_sysfs->fw_priv;
413 if (!fw_priv || fw_sysfs_done(fw_priv)) {
419 if (offset + count > fw_priv->allocated_size) {
423 firmware_rw_data(fw_priv, buffer, offset, count, false);
426 retval = fw_realloc_pages(fw_sysfs, offset + count);
431 firmware_rw(fw_priv, buffer, offset, count, false);
434 fw_priv->size = max_t(size_t, offset + count, fw_priv->size);
436 mutex_unlock(&fw_lock);
440 static struct bin_attribute firmware_attr_data = {
441 .attr = { .name = "data", .mode = 0644 },
443 .read = firmware_data_read,
444 .write = firmware_data_write,
447 static struct attribute *fw_dev_attrs[] = {
448 &dev_attr_loading.attr,
452 static struct bin_attribute *fw_dev_bin_attrs[] = {
457 static const struct attribute_group fw_dev_attr_group = {
458 .attrs = fw_dev_attrs,
459 .bin_attrs = fw_dev_bin_attrs,
462 static const struct attribute_group *fw_dev_attr_groups[] = {
467 static struct fw_sysfs *
468 fw_create_instance(struct firmware *firmware, const char *fw_name,
469 struct device *device, u32 opt_flags)
471 struct fw_sysfs *fw_sysfs;
472 struct device *f_dev;
474 fw_sysfs = kzalloc(sizeof(*fw_sysfs), GFP_KERNEL);
476 fw_sysfs = ERR_PTR(-ENOMEM);
480 fw_sysfs->nowait = !!(opt_flags & FW_OPT_NOWAIT);
481 fw_sysfs->fw = firmware;
482 f_dev = &fw_sysfs->dev;
484 device_initialize(f_dev);
485 dev_set_name(f_dev, "%s", fw_name);
486 f_dev->parent = device;
487 f_dev->class = &firmware_class;
488 f_dev->groups = fw_dev_attr_groups;
494 * fw_load_sysfs_fallback() - load a firmware via the sysfs fallback mechanism
495 * @fw_sysfs: firmware sysfs information for the firmware to load
496 * @timeout: timeout to wait for the load
498 * In charge of constructing a sysfs fallback interface for firmware loading.
500 static int fw_load_sysfs_fallback(struct fw_sysfs *fw_sysfs, long timeout)
503 struct device *f_dev = &fw_sysfs->dev;
504 struct fw_priv *fw_priv = fw_sysfs->fw_priv;
506 /* fall back on userspace loading */
508 fw_priv->is_paged_buf = true;
510 dev_set_uevent_suppress(f_dev, true);
512 retval = device_add(f_dev);
514 dev_err(f_dev, "%s: device_register failed\n", __func__);
518 mutex_lock(&fw_lock);
519 if (fw_state_is_aborted(fw_priv)) {
520 mutex_unlock(&fw_lock);
524 list_add(&fw_priv->pending_list, &pending_fw_head);
525 mutex_unlock(&fw_lock);
527 if (fw_priv->opt_flags & FW_OPT_UEVENT) {
528 fw_priv->need_uevent = true;
529 dev_set_uevent_suppress(f_dev, false);
530 dev_dbg(f_dev, "firmware: requesting %s\n", fw_priv->fw_name);
531 kobject_uevent(&fw_sysfs->dev.kobj, KOBJ_ADD);
533 timeout = MAX_JIFFY_OFFSET;
536 retval = fw_sysfs_wait_timeout(fw_priv, timeout);
537 if (retval < 0 && retval != -ENOENT) {
538 mutex_lock(&fw_lock);
539 fw_load_abort(fw_sysfs);
540 mutex_unlock(&fw_lock);
543 if (fw_state_is_aborted(fw_priv)) {
544 if (retval == -ERESTARTSYS)
546 } else if (fw_priv->is_paged_buf && !fw_priv->data)
556 static int fw_load_from_user_helper(struct firmware *firmware,
557 const char *name, struct device *device,
560 struct fw_sysfs *fw_sysfs;
564 timeout = firmware_loading_timeout();
565 if (opt_flags & FW_OPT_NOWAIT) {
566 timeout = usermodehelper_read_lock_wait(timeout);
568 dev_dbg(device, "firmware: %s loading timed out\n",
573 ret = usermodehelper_read_trylock();
575 dev_err(device, "firmware: %s will not be loaded\n",
581 fw_sysfs = fw_create_instance(firmware, name, device, opt_flags);
582 if (IS_ERR(fw_sysfs)) {
583 ret = PTR_ERR(fw_sysfs);
587 fw_sysfs->fw_priv = firmware->priv;
588 ret = fw_load_sysfs_fallback(fw_sysfs, timeout);
591 ret = assign_fw(firmware, device);
594 usermodehelper_read_unlock();
599 static bool fw_force_sysfs_fallback(u32 opt_flags)
601 if (fw_fallback_config.force_sysfs_fallback)
603 if (!(opt_flags & FW_OPT_USERHELPER))
608 static bool fw_run_sysfs_fallback(u32 opt_flags)
612 if (fw_fallback_config.ignore_sysfs_fallback) {
613 pr_info_once("Ignoring firmware sysfs fallback due to sysctl knob\n");
617 if ((opt_flags & FW_OPT_NOFALLBACK_SYSFS))
620 /* Also permit LSMs and IMA to fail firmware sysfs fallback */
621 ret = security_kernel_load_data(LOADING_FIRMWARE, true);
625 return fw_force_sysfs_fallback(opt_flags);
629 * firmware_fallback_sysfs() - use the fallback mechanism to find firmware
630 * @fw: pointer to firmware image
631 * @name: name of firmware file to look for
632 * @device: device for which firmware is being loaded
633 * @opt_flags: options to control firmware loading behaviour, as defined by
635 * @ret: return value from direct lookup which triggered the fallback mechanism
637 * This function is called if direct lookup for the firmware failed, it enables
638 * a fallback mechanism through userspace by exposing a sysfs loading
639 * interface. Userspace is in charge of loading the firmware through the sysfs
640 * loading interface. This sysfs fallback mechanism may be disabled completely
641 * on a system by setting the proc sysctl value ignore_sysfs_fallback to true.
642 * If this is false we check if the internal API caller set the
643 * @FW_OPT_NOFALLBACK_SYSFS flag, if so it would also disable the fallback
644 * mechanism. A system may want to enforce the sysfs fallback mechanism at all
645 * times, it can do this by setting ignore_sysfs_fallback to false and
646 * force_sysfs_fallback to true.
647 * Enabling force_sysfs_fallback is functionally equivalent to build a kernel
648 * with CONFIG_FW_LOADER_USER_HELPER_FALLBACK.
650 int firmware_fallback_sysfs(struct firmware *fw, const char *name,
651 struct device *device,
655 if (!fw_run_sysfs_fallback(opt_flags))
658 if (!(opt_flags & FW_OPT_NO_WARN))
659 dev_warn(device, "Falling back to sysfs fallback for: %s\n",
662 dev_dbg(device, "Falling back to sysfs fallback for: %s\n",
664 return fw_load_from_user_helper(fw, name, device, opt_flags);