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660 lines
16 KiB
660 lines
16 KiB
// SPDX-License-Identifier: GPL-2.0 |
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#include <linux/types.h> |
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#include <linux/kconfig.h> |
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#include <linux/list.h> |
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#include <linux/slab.h> |
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#include <linux/security.h> |
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#include <linux/highmem.h> |
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#include <linux/umh.h> |
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#include <linux/sysctl.h> |
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#include <linux/vmalloc.h> |
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#include <linux/module.h> |
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#include "fallback.h" |
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#include "firmware.h" |
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|
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/* |
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* firmware fallback mechanism |
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*/ |
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MODULE_IMPORT_NS(FIRMWARE_LOADER_PRIVATE); |
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extern struct firmware_fallback_config fw_fallback_config; |
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/* These getters are vetted to use int properly */ |
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static inline int __firmware_loading_timeout(void) |
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{ |
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return fw_fallback_config.loading_timeout; |
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} |
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/* These setters are vetted to use int properly */ |
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static void __fw_fallback_set_timeout(int timeout) |
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{ |
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fw_fallback_config.loading_timeout = timeout; |
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} |
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/* |
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* use small loading timeout for caching devices' firmware because all these |
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* firmware images have been loaded successfully at lease once, also system is |
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* ready for completing firmware loading now. The maximum size of firmware in |
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* current distributions is about 2M bytes, so 10 secs should be enough. |
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*/ |
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void fw_fallback_set_cache_timeout(void) |
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{ |
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fw_fallback_config.old_timeout = __firmware_loading_timeout(); |
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__fw_fallback_set_timeout(10); |
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} |
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/* Restores the timeout to the value last configured during normal operation */ |
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void fw_fallback_set_default_timeout(void) |
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{ |
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__fw_fallback_set_timeout(fw_fallback_config.old_timeout); |
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} |
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static long firmware_loading_timeout(void) |
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{ |
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return __firmware_loading_timeout() > 0 ? |
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__firmware_loading_timeout() * HZ : MAX_JIFFY_OFFSET; |
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} |
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static inline bool fw_sysfs_done(struct fw_priv *fw_priv) |
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{ |
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return __fw_state_check(fw_priv, FW_STATUS_DONE); |
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} |
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static inline bool fw_sysfs_loading(struct fw_priv *fw_priv) |
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{ |
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return __fw_state_check(fw_priv, FW_STATUS_LOADING); |
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} |
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static inline int fw_sysfs_wait_timeout(struct fw_priv *fw_priv, long timeout) |
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{ |
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return __fw_state_wait_common(fw_priv, timeout); |
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} |
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struct fw_sysfs { |
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bool nowait; |
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struct device dev; |
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struct fw_priv *fw_priv; |
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struct firmware *fw; |
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}; |
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static struct fw_sysfs *to_fw_sysfs(struct device *dev) |
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{ |
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return container_of(dev, struct fw_sysfs, dev); |
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} |
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static void __fw_load_abort(struct fw_priv *fw_priv) |
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{ |
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/* |
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* There is a small window in which user can write to 'loading' |
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* between loading done/aborted and disappearance of 'loading' |
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*/ |
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if (fw_state_is_aborted(fw_priv) || fw_sysfs_done(fw_priv)) |
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return; |
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fw_state_aborted(fw_priv); |
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} |
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static void fw_load_abort(struct fw_sysfs *fw_sysfs) |
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{ |
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struct fw_priv *fw_priv = fw_sysfs->fw_priv; |
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__fw_load_abort(fw_priv); |
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} |
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static LIST_HEAD(pending_fw_head); |
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void kill_pending_fw_fallback_reqs(bool only_kill_custom) |
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{ |
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struct fw_priv *fw_priv; |
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struct fw_priv *next; |
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mutex_lock(&fw_lock); |
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list_for_each_entry_safe(fw_priv, next, &pending_fw_head, |
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pending_list) { |
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if (!fw_priv->need_uevent || !only_kill_custom) |
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__fw_load_abort(fw_priv); |
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} |
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mutex_unlock(&fw_lock); |
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} |
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static ssize_t timeout_show(struct class *class, struct class_attribute *attr, |
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char *buf) |
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{ |
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return sysfs_emit(buf, "%d\n", __firmware_loading_timeout()); |
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} |
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/** |
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* timeout_store() - set number of seconds to wait for firmware |
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* @class: device class pointer |
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* @attr: device attribute pointer |
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* @buf: buffer to scan for timeout value |
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* @count: number of bytes in @buf |
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* |
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* Sets the number of seconds to wait for the firmware. Once |
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* this expires an error will be returned to the driver and no |
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* firmware will be provided. |
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* |
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* Note: zero means 'wait forever'. |
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**/ |
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static ssize_t timeout_store(struct class *class, struct class_attribute *attr, |
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const char *buf, size_t count) |
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{ |
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int tmp_loading_timeout = simple_strtol(buf, NULL, 10); |
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if (tmp_loading_timeout < 0) |
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tmp_loading_timeout = 0; |
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__fw_fallback_set_timeout(tmp_loading_timeout); |
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return count; |
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} |
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static CLASS_ATTR_RW(timeout); |
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static struct attribute *firmware_class_attrs[] = { |
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&class_attr_timeout.attr, |
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NULL, |
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}; |
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ATTRIBUTE_GROUPS(firmware_class); |
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static void fw_dev_release(struct device *dev) |
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{ |
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struct fw_sysfs *fw_sysfs = to_fw_sysfs(dev); |
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kfree(fw_sysfs); |
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} |
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static int do_firmware_uevent(struct fw_sysfs *fw_sysfs, struct kobj_uevent_env *env) |
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{ |
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if (add_uevent_var(env, "FIRMWARE=%s", fw_sysfs->fw_priv->fw_name)) |
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return -ENOMEM; |
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if (add_uevent_var(env, "TIMEOUT=%i", __firmware_loading_timeout())) |
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return -ENOMEM; |
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if (add_uevent_var(env, "ASYNC=%d", fw_sysfs->nowait)) |
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return -ENOMEM; |
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return 0; |
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} |
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static int firmware_uevent(struct device *dev, struct kobj_uevent_env *env) |
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{ |
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struct fw_sysfs *fw_sysfs = to_fw_sysfs(dev); |
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int err = 0; |
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mutex_lock(&fw_lock); |
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if (fw_sysfs->fw_priv) |
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err = do_firmware_uevent(fw_sysfs, env); |
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mutex_unlock(&fw_lock); |
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return err; |
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} |
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static struct class firmware_class = { |
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.name = "firmware", |
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.class_groups = firmware_class_groups, |
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.dev_uevent = firmware_uevent, |
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.dev_release = fw_dev_release, |
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}; |
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int register_sysfs_loader(void) |
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{ |
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return class_register(&firmware_class); |
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} |
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void unregister_sysfs_loader(void) |
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{ |
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class_unregister(&firmware_class); |
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} |
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static ssize_t firmware_loading_show(struct device *dev, |
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struct device_attribute *attr, char *buf) |
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{ |
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struct fw_sysfs *fw_sysfs = to_fw_sysfs(dev); |
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int loading = 0; |
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mutex_lock(&fw_lock); |
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if (fw_sysfs->fw_priv) |
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loading = fw_sysfs_loading(fw_sysfs->fw_priv); |
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mutex_unlock(&fw_lock); |
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return sysfs_emit(buf, "%d\n", loading); |
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} |
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/** |
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* firmware_loading_store() - set value in the 'loading' control file |
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* @dev: device pointer |
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* @attr: device attribute pointer |
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* @buf: buffer to scan for loading control value |
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* @count: number of bytes in @buf |
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* |
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* The relevant values are: |
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* |
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* 1: Start a load, discarding any previous partial load. |
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* 0: Conclude the load and hand the data to the driver code. |
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* -1: Conclude the load with an error and discard any written data. |
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**/ |
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static ssize_t firmware_loading_store(struct device *dev, |
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struct device_attribute *attr, |
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const char *buf, size_t count) |
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{ |
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struct fw_sysfs *fw_sysfs = to_fw_sysfs(dev); |
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struct fw_priv *fw_priv; |
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ssize_t written = count; |
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int loading = simple_strtol(buf, NULL, 10); |
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mutex_lock(&fw_lock); |
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fw_priv = fw_sysfs->fw_priv; |
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if (fw_state_is_aborted(fw_priv)) |
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goto out; |
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switch (loading) { |
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case 1: |
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/* discarding any previous partial load */ |
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if (!fw_sysfs_done(fw_priv)) { |
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fw_free_paged_buf(fw_priv); |
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fw_state_start(fw_priv); |
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} |
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break; |
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case 0: |
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if (fw_sysfs_loading(fw_priv)) { |
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int rc; |
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/* |
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* Several loading requests may be pending on |
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* one same firmware buf, so let all requests |
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* see the mapped 'buf->data' once the loading |
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* is completed. |
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* */ |
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rc = fw_map_paged_buf(fw_priv); |
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if (rc) |
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dev_err(dev, "%s: map pages failed\n", |
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__func__); |
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else |
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rc = security_kernel_post_load_data(fw_priv->data, |
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fw_priv->size, |
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LOADING_FIRMWARE, "blob"); |
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/* |
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* Same logic as fw_load_abort, only the DONE bit |
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* is ignored and we set ABORT only on failure. |
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*/ |
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if (rc) { |
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fw_state_aborted(fw_priv); |
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written = rc; |
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} else { |
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fw_state_done(fw_priv); |
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} |
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break; |
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} |
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fallthrough; |
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default: |
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dev_err(dev, "%s: unexpected value (%d)\n", __func__, loading); |
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fallthrough; |
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case -1: |
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fw_load_abort(fw_sysfs); |
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break; |
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} |
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out: |
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mutex_unlock(&fw_lock); |
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return written; |
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} |
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static DEVICE_ATTR(loading, 0644, firmware_loading_show, firmware_loading_store); |
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static void firmware_rw_data(struct fw_priv *fw_priv, char *buffer, |
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loff_t offset, size_t count, bool read) |
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{ |
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if (read) |
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memcpy(buffer, fw_priv->data + offset, count); |
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else |
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memcpy(fw_priv->data + offset, buffer, count); |
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} |
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static void firmware_rw(struct fw_priv *fw_priv, char *buffer, |
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loff_t offset, size_t count, bool read) |
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{ |
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while (count) { |
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void *page_data; |
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int page_nr = offset >> PAGE_SHIFT; |
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int page_ofs = offset & (PAGE_SIZE-1); |
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int page_cnt = min_t(size_t, PAGE_SIZE - page_ofs, count); |
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page_data = kmap(fw_priv->pages[page_nr]); |
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if (read) |
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memcpy(buffer, page_data + page_ofs, page_cnt); |
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else |
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memcpy(page_data + page_ofs, buffer, page_cnt); |
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kunmap(fw_priv->pages[page_nr]); |
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buffer += page_cnt; |
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offset += page_cnt; |
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count -= page_cnt; |
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} |
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} |
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static ssize_t firmware_data_read(struct file *filp, struct kobject *kobj, |
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struct bin_attribute *bin_attr, |
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char *buffer, loff_t offset, size_t count) |
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{ |
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struct device *dev = kobj_to_dev(kobj); |
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struct fw_sysfs *fw_sysfs = to_fw_sysfs(dev); |
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struct fw_priv *fw_priv; |
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ssize_t ret_count; |
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mutex_lock(&fw_lock); |
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fw_priv = fw_sysfs->fw_priv; |
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if (!fw_priv || fw_sysfs_done(fw_priv)) { |
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ret_count = -ENODEV; |
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goto out; |
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} |
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if (offset > fw_priv->size) { |
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ret_count = 0; |
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goto out; |
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} |
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if (count > fw_priv->size - offset) |
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count = fw_priv->size - offset; |
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ret_count = count; |
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if (fw_priv->data) |
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firmware_rw_data(fw_priv, buffer, offset, count, true); |
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else |
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firmware_rw(fw_priv, buffer, offset, count, true); |
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out: |
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mutex_unlock(&fw_lock); |
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return ret_count; |
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} |
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static int fw_realloc_pages(struct fw_sysfs *fw_sysfs, int min_size) |
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{ |
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int err; |
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err = fw_grow_paged_buf(fw_sysfs->fw_priv, |
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PAGE_ALIGN(min_size) >> PAGE_SHIFT); |
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if (err) |
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fw_load_abort(fw_sysfs); |
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return err; |
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} |
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/** |
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* firmware_data_write() - write method for firmware |
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* @filp: open sysfs file |
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* @kobj: kobject for the device |
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* @bin_attr: bin_attr structure |
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* @buffer: buffer being written |
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* @offset: buffer offset for write in total data store area |
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* @count: buffer size |
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* |
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* Data written to the 'data' attribute will be later handed to |
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* the driver as a firmware image. |
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**/ |
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static ssize_t firmware_data_write(struct file *filp, struct kobject *kobj, |
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struct bin_attribute *bin_attr, |
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char *buffer, loff_t offset, size_t count) |
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{ |
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struct device *dev = kobj_to_dev(kobj); |
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struct fw_sysfs *fw_sysfs = to_fw_sysfs(dev); |
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struct fw_priv *fw_priv; |
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ssize_t retval; |
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if (!capable(CAP_SYS_RAWIO)) |
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return -EPERM; |
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mutex_lock(&fw_lock); |
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fw_priv = fw_sysfs->fw_priv; |
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if (!fw_priv || fw_sysfs_done(fw_priv)) { |
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retval = -ENODEV; |
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goto out; |
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} |
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if (fw_priv->data) { |
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if (offset + count > fw_priv->allocated_size) { |
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retval = -ENOMEM; |
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goto out; |
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} |
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firmware_rw_data(fw_priv, buffer, offset, count, false); |
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retval = count; |
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} else { |
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retval = fw_realloc_pages(fw_sysfs, offset + count); |
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if (retval) |
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goto out; |
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retval = count; |
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firmware_rw(fw_priv, buffer, offset, count, false); |
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} |
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fw_priv->size = max_t(size_t, offset + count, fw_priv->size); |
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out: |
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mutex_unlock(&fw_lock); |
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return retval; |
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} |
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static struct bin_attribute firmware_attr_data = { |
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.attr = { .name = "data", .mode = 0644 }, |
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.size = 0, |
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.read = firmware_data_read, |
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.write = firmware_data_write, |
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}; |
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static struct attribute *fw_dev_attrs[] = { |
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&dev_attr_loading.attr, |
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NULL |
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}; |
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static struct bin_attribute *fw_dev_bin_attrs[] = { |
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&firmware_attr_data, |
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NULL |
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}; |
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static const struct attribute_group fw_dev_attr_group = { |
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.attrs = fw_dev_attrs, |
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.bin_attrs = fw_dev_bin_attrs, |
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}; |
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static const struct attribute_group *fw_dev_attr_groups[] = { |
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&fw_dev_attr_group, |
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NULL |
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}; |
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static struct fw_sysfs * |
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fw_create_instance(struct firmware *firmware, const char *fw_name, |
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struct device *device, u32 opt_flags) |
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{ |
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struct fw_sysfs *fw_sysfs; |
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struct device *f_dev; |
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fw_sysfs = kzalloc(sizeof(*fw_sysfs), GFP_KERNEL); |
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if (!fw_sysfs) { |
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fw_sysfs = ERR_PTR(-ENOMEM); |
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goto exit; |
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} |
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fw_sysfs->nowait = !!(opt_flags & FW_OPT_NOWAIT); |
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fw_sysfs->fw = firmware; |
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f_dev = &fw_sysfs->dev; |
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device_initialize(f_dev); |
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dev_set_name(f_dev, "%s", fw_name); |
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f_dev->parent = device; |
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f_dev->class = &firmware_class; |
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f_dev->groups = fw_dev_attr_groups; |
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exit: |
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return fw_sysfs; |
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} |
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|
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/** |
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* fw_load_sysfs_fallback() - load a firmware via the sysfs fallback mechanism |
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* @fw_sysfs: firmware sysfs information for the firmware to load |
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* @timeout: timeout to wait for the load |
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* |
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* In charge of constructing a sysfs fallback interface for firmware loading. |
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**/ |
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static int fw_load_sysfs_fallback(struct fw_sysfs *fw_sysfs, long timeout) |
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{ |
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int retval = 0; |
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struct device *f_dev = &fw_sysfs->dev; |
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struct fw_priv *fw_priv = fw_sysfs->fw_priv; |
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|
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/* fall back on userspace loading */ |
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if (!fw_priv->data) |
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fw_priv->is_paged_buf = true; |
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dev_set_uevent_suppress(f_dev, true); |
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retval = device_add(f_dev); |
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if (retval) { |
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dev_err(f_dev, "%s: device_register failed\n", __func__); |
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goto err_put_dev; |
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} |
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mutex_lock(&fw_lock); |
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if (fw_state_is_aborted(fw_priv)) { |
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mutex_unlock(&fw_lock); |
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retval = -EINTR; |
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goto out; |
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} |
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list_add(&fw_priv->pending_list, &pending_fw_head); |
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mutex_unlock(&fw_lock); |
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|
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if (fw_priv->opt_flags & FW_OPT_UEVENT) { |
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fw_priv->need_uevent = true; |
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dev_set_uevent_suppress(f_dev, false); |
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dev_dbg(f_dev, "firmware: requesting %s\n", fw_priv->fw_name); |
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kobject_uevent(&fw_sysfs->dev.kobj, KOBJ_ADD); |
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} else { |
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timeout = MAX_JIFFY_OFFSET; |
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} |
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retval = fw_sysfs_wait_timeout(fw_priv, timeout); |
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if (retval < 0 && retval != -ENOENT) { |
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mutex_lock(&fw_lock); |
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fw_load_abort(fw_sysfs); |
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mutex_unlock(&fw_lock); |
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} |
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if (fw_state_is_aborted(fw_priv)) { |
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if (retval == -ERESTARTSYS) |
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retval = -EINTR; |
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} else if (fw_priv->is_paged_buf && !fw_priv->data) |
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retval = -ENOMEM; |
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out: |
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device_del(f_dev); |
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err_put_dev: |
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put_device(f_dev); |
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return retval; |
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} |
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|
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static int fw_load_from_user_helper(struct firmware *firmware, |
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const char *name, struct device *device, |
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u32 opt_flags) |
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{ |
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struct fw_sysfs *fw_sysfs; |
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long timeout; |
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int ret; |
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timeout = firmware_loading_timeout(); |
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if (opt_flags & FW_OPT_NOWAIT) { |
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timeout = usermodehelper_read_lock_wait(timeout); |
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if (!timeout) { |
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dev_dbg(device, "firmware: %s loading timed out\n", |
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name); |
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return -EBUSY; |
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} |
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} else { |
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ret = usermodehelper_read_trylock(); |
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if (WARN_ON(ret)) { |
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dev_err(device, "firmware: %s will not be loaded\n", |
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name); |
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return ret; |
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} |
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} |
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fw_sysfs = fw_create_instance(firmware, name, device, opt_flags); |
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if (IS_ERR(fw_sysfs)) { |
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ret = PTR_ERR(fw_sysfs); |
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goto out_unlock; |
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} |
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|
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fw_sysfs->fw_priv = firmware->priv; |
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ret = fw_load_sysfs_fallback(fw_sysfs, timeout); |
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|
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if (!ret) |
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ret = assign_fw(firmware, device); |
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|
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out_unlock: |
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usermodehelper_read_unlock(); |
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|
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return ret; |
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} |
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|
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static bool fw_force_sysfs_fallback(u32 opt_flags) |
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{ |
|
if (fw_fallback_config.force_sysfs_fallback) |
|
return true; |
|
if (!(opt_flags & FW_OPT_USERHELPER)) |
|
return false; |
|
return true; |
|
} |
|
|
|
static bool fw_run_sysfs_fallback(u32 opt_flags) |
|
{ |
|
int ret; |
|
|
|
if (fw_fallback_config.ignore_sysfs_fallback) { |
|
pr_info_once("Ignoring firmware sysfs fallback due to sysctl knob\n"); |
|
return false; |
|
} |
|
|
|
if ((opt_flags & FW_OPT_NOFALLBACK_SYSFS)) |
|
return false; |
|
|
|
/* Also permit LSMs and IMA to fail firmware sysfs fallback */ |
|
ret = security_kernel_load_data(LOADING_FIRMWARE, true); |
|
if (ret < 0) |
|
return false; |
|
|
|
return fw_force_sysfs_fallback(opt_flags); |
|
} |
|
|
|
/** |
|
* firmware_fallback_sysfs() - use the fallback mechanism to find firmware |
|
* @fw: pointer to firmware image |
|
* @name: name of firmware file to look for |
|
* @device: device for which firmware is being loaded |
|
* @opt_flags: options to control firmware loading behaviour, as defined by |
|
* &enum fw_opt |
|
* @ret: return value from direct lookup which triggered the fallback mechanism |
|
* |
|
* This function is called if direct lookup for the firmware failed, it enables |
|
* a fallback mechanism through userspace by exposing a sysfs loading |
|
* interface. Userspace is in charge of loading the firmware through the sysfs |
|
* loading interface. This sysfs fallback mechanism may be disabled completely |
|
* on a system by setting the proc sysctl value ignore_sysfs_fallback to true. |
|
* If this is false we check if the internal API caller set the |
|
* @FW_OPT_NOFALLBACK_SYSFS flag, if so it would also disable the fallback |
|
* mechanism. A system may want to enforce the sysfs fallback mechanism at all |
|
* times, it can do this by setting ignore_sysfs_fallback to false and |
|
* force_sysfs_fallback to true. |
|
* Enabling force_sysfs_fallback is functionally equivalent to build a kernel |
|
* with CONFIG_FW_LOADER_USER_HELPER_FALLBACK. |
|
**/ |
|
int firmware_fallback_sysfs(struct firmware *fw, const char *name, |
|
struct device *device, |
|
u32 opt_flags, |
|
int ret) |
|
{ |
|
if (!fw_run_sysfs_fallback(opt_flags)) |
|
return ret; |
|
|
|
if (!(opt_flags & FW_OPT_NO_WARN)) |
|
dev_warn(device, "Falling back to sysfs fallback for: %s\n", |
|
name); |
|
else |
|
dev_dbg(device, "Falling back to sysfs fallback for: %s\n", |
|
name); |
|
return fw_load_from_user_helper(fw, name, device, opt_flags); |
|
}
|
|
|