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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
commit | 2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch) | |
tree | 848558de17fb3008cdf4d861b01ac7781903ce39 /drivers/base/firmware_loader/fallback.c | |
parent | Initial commit. (diff) | |
download | linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip |
Adding upstream version 6.1.76.upstream/6.1.76
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'drivers/base/firmware_loader/fallback.c')
-rw-r--r-- | drivers/base/firmware_loader/fallback.c | 235 |
1 files changed, 235 insertions, 0 deletions
diff --git a/drivers/base/firmware_loader/fallback.c b/drivers/base/firmware_loader/fallback.c new file mode 100644 index 000000000..bf68e3947 --- /dev/null +++ b/drivers/base/firmware_loader/fallback.c @@ -0,0 +1,235 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include <linux/types.h> +#include <linux/kconfig.h> +#include <linux/list.h> +#include <linux/security.h> +#include <linux/umh.h> +#include <linux/sysctl.h> +#include <linux/module.h> + +#include "fallback.h" +#include "firmware.h" + +/* + * firmware fallback mechanism + */ + +/* + * use small loading timeout for caching devices' firmware because all these + * firmware images have been loaded successfully at lease once, also system is + * ready for completing firmware loading now. The maximum size of firmware in + * current distributions is about 2M bytes, so 10 secs should be enough. + */ +void fw_fallback_set_cache_timeout(void) +{ + fw_fallback_config.old_timeout = __firmware_loading_timeout(); + __fw_fallback_set_timeout(10); +} + +/* Restores the timeout to the value last configured during normal operation */ +void fw_fallback_set_default_timeout(void) +{ + __fw_fallback_set_timeout(fw_fallback_config.old_timeout); +} + +static long firmware_loading_timeout(void) +{ + return __firmware_loading_timeout() > 0 ? + __firmware_loading_timeout() * HZ : MAX_JIFFY_OFFSET; +} + +static inline int fw_sysfs_wait_timeout(struct fw_priv *fw_priv, long timeout) +{ + return __fw_state_wait_common(fw_priv, timeout); +} + +static LIST_HEAD(pending_fw_head); + +void kill_pending_fw_fallback_reqs(bool only_kill_custom) +{ + struct fw_priv *fw_priv; + struct fw_priv *next; + + mutex_lock(&fw_lock); + list_for_each_entry_safe(fw_priv, next, &pending_fw_head, + pending_list) { + if (!fw_priv->need_uevent || !only_kill_custom) + __fw_load_abort(fw_priv); + } + mutex_unlock(&fw_lock); +} + +/** + * fw_load_sysfs_fallback() - load a firmware via the sysfs fallback mechanism + * @fw_sysfs: firmware sysfs information for the firmware to load + * @timeout: timeout to wait for the load + * + * In charge of constructing a sysfs fallback interface for firmware loading. + **/ +static int fw_load_sysfs_fallback(struct fw_sysfs *fw_sysfs, long timeout) +{ + int retval = 0; + struct device *f_dev = &fw_sysfs->dev; + struct fw_priv *fw_priv = fw_sysfs->fw_priv; + + /* fall back on userspace loading */ + if (!fw_priv->data) + fw_priv->is_paged_buf = true; + + dev_set_uevent_suppress(f_dev, true); + + retval = device_add(f_dev); + if (retval) { + dev_err(f_dev, "%s: device_register failed\n", __func__); + goto err_put_dev; + } + + mutex_lock(&fw_lock); + if (fw_state_is_aborted(fw_priv)) { + mutex_unlock(&fw_lock); + retval = -EINTR; + goto out; + } + list_add(&fw_priv->pending_list, &pending_fw_head); + mutex_unlock(&fw_lock); + + if (fw_priv->opt_flags & FW_OPT_UEVENT) { + fw_priv->need_uevent = true; + dev_set_uevent_suppress(f_dev, false); + dev_dbg(f_dev, "firmware: requesting %s\n", fw_priv->fw_name); + kobject_uevent(&fw_sysfs->dev.kobj, KOBJ_ADD); + } else { + timeout = MAX_JIFFY_OFFSET; + } + + retval = fw_sysfs_wait_timeout(fw_priv, timeout); + if (retval < 0 && retval != -ENOENT) { + mutex_lock(&fw_lock); + fw_load_abort(fw_sysfs); + mutex_unlock(&fw_lock); + } + + if (fw_state_is_aborted(fw_priv)) { + if (retval == -ERESTARTSYS) + retval = -EINTR; + } else if (fw_priv->is_paged_buf && !fw_priv->data) + retval = -ENOMEM; + +out: + device_del(f_dev); +err_put_dev: + put_device(f_dev); + return retval; +} + +static int fw_load_from_user_helper(struct firmware *firmware, + const char *name, struct device *device, + u32 opt_flags) +{ + struct fw_sysfs *fw_sysfs; + long timeout; + int ret; + + timeout = firmware_loading_timeout(); + if (opt_flags & FW_OPT_NOWAIT) { + timeout = usermodehelper_read_lock_wait(timeout); + if (!timeout) { + dev_dbg(device, "firmware: %s loading timed out\n", + name); + return -EBUSY; + } + } else { + ret = usermodehelper_read_trylock(); + if (WARN_ON(ret)) { + dev_err(device, "firmware: %s will not be loaded\n", + name); + return ret; + } + } + + fw_sysfs = fw_create_instance(firmware, name, device, opt_flags); + if (IS_ERR(fw_sysfs)) { + ret = PTR_ERR(fw_sysfs); + goto out_unlock; + } + + fw_sysfs->fw_priv = firmware->priv; + ret = fw_load_sysfs_fallback(fw_sysfs, timeout); + + if (!ret) + ret = assign_fw(firmware, device); + +out_unlock: + usermodehelper_read_unlock(); + + return ret; +} + +static bool fw_force_sysfs_fallback(u32 opt_flags) +{ + 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); +} |