v4.19.13 snapshot.
diff --git a/drivers/base/firmware_loader/fallback.c b/drivers/base/firmware_loader/fallback.c
new file mode 100644
index 0000000..b5c865f
--- /dev/null
+++ b/drivers/base/firmware_loader/fallback.c
@@ -0,0 +1,702 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/types.h>
+#include <linux/kconfig.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+#include <linux/security.h>
+#include <linux/highmem.h>
+#include <linux/umh.h>
+#include <linux/sysctl.h>
+#include <linux/vmalloc.h>
+
+#include "fallback.h"
+#include "firmware.h"
+
+/*
+ * firmware fallback mechanism
+ */
+
+extern struct firmware_fallback_config fw_fallback_config;
+
+/* These getters are vetted to use int properly */
+static inline int __firmware_loading_timeout(void)
+{
+ return fw_fallback_config.loading_timeout;
+}
+
+/* These setters are vetted to use int properly */
+static void __fw_fallback_set_timeout(int timeout)
+{
+ fw_fallback_config.loading_timeout = timeout;
+}
+
+/*
+ * 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 bool fw_sysfs_done(struct fw_priv *fw_priv)
+{
+ return __fw_state_check(fw_priv, FW_STATUS_DONE);
+}
+
+static inline bool fw_sysfs_loading(struct fw_priv *fw_priv)
+{
+ return __fw_state_check(fw_priv, FW_STATUS_LOADING);
+}
+
+static inline int fw_sysfs_wait_timeout(struct fw_priv *fw_priv, long timeout)
+{
+ return __fw_state_wait_common(fw_priv, timeout);
+}
+
+struct fw_sysfs {
+ bool nowait;
+ struct device dev;
+ struct fw_priv *fw_priv;
+ struct firmware *fw;
+};
+
+static struct fw_sysfs *to_fw_sysfs(struct device *dev)
+{
+ return container_of(dev, struct fw_sysfs, dev);
+}
+
+static void __fw_load_abort(struct fw_priv *fw_priv)
+{
+ /*
+ * There is a small window in which user can write to 'loading'
+ * between loading done and disappearance of 'loading'
+ */
+ if (fw_sysfs_done(fw_priv))
+ return;
+
+ list_del_init(&fw_priv->pending_list);
+ fw_state_aborted(fw_priv);
+}
+
+static void fw_load_abort(struct fw_sysfs *fw_sysfs)
+{
+ struct fw_priv *fw_priv = fw_sysfs->fw_priv;
+
+ __fw_load_abort(fw_priv);
+}
+
+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);
+}
+
+static ssize_t timeout_show(struct class *class, struct class_attribute *attr,
+ char *buf)
+{
+ return sprintf(buf, "%d\n", __firmware_loading_timeout());
+}
+
+/**
+ * firmware_timeout_store() - set number of seconds to wait for firmware
+ * @class: device class pointer
+ * @attr: device attribute pointer
+ * @buf: buffer to scan for timeout value
+ * @count: number of bytes in @buf
+ *
+ * Sets the number of seconds to wait for the firmware. Once
+ * this expires an error will be returned to the driver and no
+ * firmware will be provided.
+ *
+ * Note: zero means 'wait forever'.
+ **/
+static ssize_t timeout_store(struct class *class, struct class_attribute *attr,
+ const char *buf, size_t count)
+{
+ int tmp_loading_timeout = simple_strtol(buf, NULL, 10);
+
+ if (tmp_loading_timeout < 0)
+ tmp_loading_timeout = 0;
+
+ __fw_fallback_set_timeout(tmp_loading_timeout);
+
+ return count;
+}
+static CLASS_ATTR_RW(timeout);
+
+static struct attribute *firmware_class_attrs[] = {
+ &class_attr_timeout.attr,
+ NULL,
+};
+ATTRIBUTE_GROUPS(firmware_class);
+
+static void fw_dev_release(struct device *dev)
+{
+ struct fw_sysfs *fw_sysfs = to_fw_sysfs(dev);
+
+ kfree(fw_sysfs);
+}
+
+static int do_firmware_uevent(struct fw_sysfs *fw_sysfs, struct kobj_uevent_env *env)
+{
+ if (add_uevent_var(env, "FIRMWARE=%s", fw_sysfs->fw_priv->fw_name))
+ return -ENOMEM;
+ if (add_uevent_var(env, "TIMEOUT=%i", __firmware_loading_timeout()))
+ return -ENOMEM;
+ if (add_uevent_var(env, "ASYNC=%d", fw_sysfs->nowait))
+ return -ENOMEM;
+
+ return 0;
+}
+
+static int firmware_uevent(struct device *dev, struct kobj_uevent_env *env)
+{
+ struct fw_sysfs *fw_sysfs = to_fw_sysfs(dev);
+ int err = 0;
+
+ mutex_lock(&fw_lock);
+ if (fw_sysfs->fw_priv)
+ err = do_firmware_uevent(fw_sysfs, env);
+ mutex_unlock(&fw_lock);
+ return err;
+}
+
+static struct class firmware_class = {
+ .name = "firmware",
+ .class_groups = firmware_class_groups,
+ .dev_uevent = firmware_uevent,
+ .dev_release = fw_dev_release,
+};
+
+int register_sysfs_loader(void)
+{
+ return class_register(&firmware_class);
+}
+
+void unregister_sysfs_loader(void)
+{
+ class_unregister(&firmware_class);
+}
+
+static ssize_t firmware_loading_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct fw_sysfs *fw_sysfs = to_fw_sysfs(dev);
+ int loading = 0;
+
+ mutex_lock(&fw_lock);
+ if (fw_sysfs->fw_priv)
+ loading = fw_sysfs_loading(fw_sysfs->fw_priv);
+ mutex_unlock(&fw_lock);
+
+ return sprintf(buf, "%d\n", loading);
+}
+
+/* one pages buffer should be mapped/unmapped only once */
+static int map_fw_priv_pages(struct fw_priv *fw_priv)
+{
+ if (!fw_priv->is_paged_buf)
+ return 0;
+
+ vunmap(fw_priv->data);
+ fw_priv->data = vmap(fw_priv->pages, fw_priv->nr_pages, 0,
+ PAGE_KERNEL_RO);
+ if (!fw_priv->data)
+ return -ENOMEM;
+ return 0;
+}
+
+/**
+ * firmware_loading_store() - set value in the 'loading' control file
+ * @dev: device pointer
+ * @attr: device attribute pointer
+ * @buf: buffer to scan for loading control value
+ * @count: number of bytes in @buf
+ *
+ * The relevant values are:
+ *
+ * 1: Start a load, discarding any previous partial load.
+ * 0: Conclude the load and hand the data to the driver code.
+ * -1: Conclude the load with an error and discard any written data.
+ **/
+static ssize_t firmware_loading_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct fw_sysfs *fw_sysfs = to_fw_sysfs(dev);
+ struct fw_priv *fw_priv;
+ ssize_t written = count;
+ int loading = simple_strtol(buf, NULL, 10);
+ int i;
+
+ mutex_lock(&fw_lock);
+ fw_priv = fw_sysfs->fw_priv;
+ if (fw_state_is_aborted(fw_priv))
+ goto out;
+
+ switch (loading) {
+ case 1:
+ /* discarding any previous partial load */
+ if (!fw_sysfs_done(fw_priv)) {
+ for (i = 0; i < fw_priv->nr_pages; i++)
+ __free_page(fw_priv->pages[i]);
+ vfree(fw_priv->pages);
+ fw_priv->pages = NULL;
+ fw_priv->page_array_size = 0;
+ fw_priv->nr_pages = 0;
+ fw_state_start(fw_priv);
+ }
+ break;
+ case 0:
+ if (fw_sysfs_loading(fw_priv)) {
+ int rc;
+
+ /*
+ * Several loading requests may be pending on
+ * one same firmware buf, so let all requests
+ * see the mapped 'buf->data' once the loading
+ * is completed.
+ * */
+ rc = map_fw_priv_pages(fw_priv);
+ if (rc)
+ dev_err(dev, "%s: map pages failed\n",
+ __func__);
+ else
+ rc = security_kernel_post_read_file(NULL,
+ fw_priv->data, fw_priv->size,
+ READING_FIRMWARE);
+
+ /*
+ * Same logic as fw_load_abort, only the DONE bit
+ * is ignored and we set ABORT only on failure.
+ */
+ list_del_init(&fw_priv->pending_list);
+ if (rc) {
+ fw_state_aborted(fw_priv);
+ written = rc;
+ } else {
+ fw_state_done(fw_priv);
+ }
+ break;
+ }
+ /* fallthrough */
+ default:
+ dev_err(dev, "%s: unexpected value (%d)\n", __func__, loading);
+ /* fallthrough */
+ case -1:
+ fw_load_abort(fw_sysfs);
+ break;
+ }
+out:
+ mutex_unlock(&fw_lock);
+ return written;
+}
+
+static DEVICE_ATTR(loading, 0644, firmware_loading_show, firmware_loading_store);
+
+static void firmware_rw_data(struct fw_priv *fw_priv, char *buffer,
+ loff_t offset, size_t count, bool read)
+{
+ if (read)
+ memcpy(buffer, fw_priv->data + offset, count);
+ else
+ memcpy(fw_priv->data + offset, buffer, count);
+}
+
+static void firmware_rw(struct fw_priv *fw_priv, char *buffer,
+ loff_t offset, size_t count, bool read)
+{
+ while (count) {
+ void *page_data;
+ int page_nr = offset >> PAGE_SHIFT;
+ int page_ofs = offset & (PAGE_SIZE-1);
+ int page_cnt = min_t(size_t, PAGE_SIZE - page_ofs, count);
+
+ page_data = kmap(fw_priv->pages[page_nr]);
+
+ if (read)
+ memcpy(buffer, page_data + page_ofs, page_cnt);
+ else
+ memcpy(page_data + page_ofs, buffer, page_cnt);
+
+ kunmap(fw_priv->pages[page_nr]);
+ buffer += page_cnt;
+ offset += page_cnt;
+ count -= page_cnt;
+ }
+}
+
+static ssize_t firmware_data_read(struct file *filp, struct kobject *kobj,
+ struct bin_attribute *bin_attr,
+ char *buffer, loff_t offset, size_t count)
+{
+ struct device *dev = kobj_to_dev(kobj);
+ struct fw_sysfs *fw_sysfs = to_fw_sysfs(dev);
+ struct fw_priv *fw_priv;
+ ssize_t ret_count;
+
+ mutex_lock(&fw_lock);
+ fw_priv = fw_sysfs->fw_priv;
+ if (!fw_priv || fw_sysfs_done(fw_priv)) {
+ ret_count = -ENODEV;
+ goto out;
+ }
+ if (offset > fw_priv->size) {
+ ret_count = 0;
+ goto out;
+ }
+ if (count > fw_priv->size - offset)
+ count = fw_priv->size - offset;
+
+ ret_count = count;
+
+ if (fw_priv->data)
+ firmware_rw_data(fw_priv, buffer, offset, count, true);
+ else
+ firmware_rw(fw_priv, buffer, offset, count, true);
+
+out:
+ mutex_unlock(&fw_lock);
+ return ret_count;
+}
+
+static int fw_realloc_pages(struct fw_sysfs *fw_sysfs, int min_size)
+{
+ struct fw_priv *fw_priv= fw_sysfs->fw_priv;
+ int pages_needed = PAGE_ALIGN(min_size) >> PAGE_SHIFT;
+
+ /* If the array of pages is too small, grow it... */
+ if (fw_priv->page_array_size < pages_needed) {
+ int new_array_size = max(pages_needed,
+ fw_priv->page_array_size * 2);
+ struct page **new_pages;
+
+ new_pages = vmalloc(array_size(new_array_size, sizeof(void *)));
+ if (!new_pages) {
+ fw_load_abort(fw_sysfs);
+ return -ENOMEM;
+ }
+ memcpy(new_pages, fw_priv->pages,
+ fw_priv->page_array_size * sizeof(void *));
+ memset(&new_pages[fw_priv->page_array_size], 0, sizeof(void *) *
+ (new_array_size - fw_priv->page_array_size));
+ vfree(fw_priv->pages);
+ fw_priv->pages = new_pages;
+ fw_priv->page_array_size = new_array_size;
+ }
+
+ while (fw_priv->nr_pages < pages_needed) {
+ fw_priv->pages[fw_priv->nr_pages] =
+ alloc_page(GFP_KERNEL | __GFP_HIGHMEM);
+
+ if (!fw_priv->pages[fw_priv->nr_pages]) {
+ fw_load_abort(fw_sysfs);
+ return -ENOMEM;
+ }
+ fw_priv->nr_pages++;
+ }
+ return 0;
+}
+
+/**
+ * firmware_data_write() - write method for firmware
+ * @filp: open sysfs file
+ * @kobj: kobject for the device
+ * @bin_attr: bin_attr structure
+ * @buffer: buffer being written
+ * @offset: buffer offset for write in total data store area
+ * @count: buffer size
+ *
+ * Data written to the 'data' attribute will be later handed to
+ * the driver as a firmware image.
+ **/
+static ssize_t firmware_data_write(struct file *filp, struct kobject *kobj,
+ struct bin_attribute *bin_attr,
+ char *buffer, loff_t offset, size_t count)
+{
+ struct device *dev = kobj_to_dev(kobj);
+ struct fw_sysfs *fw_sysfs = to_fw_sysfs(dev);
+ struct fw_priv *fw_priv;
+ ssize_t retval;
+
+ if (!capable(CAP_SYS_RAWIO))
+ return -EPERM;
+
+ mutex_lock(&fw_lock);
+ fw_priv = fw_sysfs->fw_priv;
+ if (!fw_priv || fw_sysfs_done(fw_priv)) {
+ retval = -ENODEV;
+ goto out;
+ }
+
+ if (fw_priv->data) {
+ if (offset + count > fw_priv->allocated_size) {
+ retval = -ENOMEM;
+ goto out;
+ }
+ firmware_rw_data(fw_priv, buffer, offset, count, false);
+ retval = count;
+ } else {
+ retval = fw_realloc_pages(fw_sysfs, offset + count);
+ if (retval)
+ goto out;
+
+ retval = count;
+ firmware_rw(fw_priv, buffer, offset, count, false);
+ }
+
+ fw_priv->size = max_t(size_t, offset + count, fw_priv->size);
+out:
+ mutex_unlock(&fw_lock);
+ return retval;
+}
+
+static struct bin_attribute firmware_attr_data = {
+ .attr = { .name = "data", .mode = 0644 },
+ .size = 0,
+ .read = firmware_data_read,
+ .write = firmware_data_write,
+};
+
+static struct attribute *fw_dev_attrs[] = {
+ &dev_attr_loading.attr,
+ NULL
+};
+
+static struct bin_attribute *fw_dev_bin_attrs[] = {
+ &firmware_attr_data,
+ NULL
+};
+
+static const struct attribute_group fw_dev_attr_group = {
+ .attrs = fw_dev_attrs,
+ .bin_attrs = fw_dev_bin_attrs,
+};
+
+static const struct attribute_group *fw_dev_attr_groups[] = {
+ &fw_dev_attr_group,
+ NULL
+};
+
+static struct fw_sysfs *
+fw_create_instance(struct firmware *firmware, const char *fw_name,
+ struct device *device, enum fw_opt opt_flags)
+{
+ struct fw_sysfs *fw_sysfs;
+ struct device *f_dev;
+
+ fw_sysfs = kzalloc(sizeof(*fw_sysfs), GFP_KERNEL);
+ if (!fw_sysfs) {
+ fw_sysfs = ERR_PTR(-ENOMEM);
+ goto exit;
+ }
+
+ fw_sysfs->nowait = !!(opt_flags & FW_OPT_NOWAIT);
+ fw_sysfs->fw = firmware;
+ f_dev = &fw_sysfs->dev;
+
+ device_initialize(f_dev);
+ dev_set_name(f_dev, "%s", fw_name);
+ f_dev->parent = device;
+ f_dev->class = &firmware_class;
+ f_dev->groups = fw_dev_attr_groups;
+exit:
+ return fw_sysfs;
+}
+
+/**
+ * fw_load_sysfs_fallback() - load a firmware via the sysfs fallback mechanism
+ * @fw_sysfs: firmware sysfs information for the firmware to load
+ * @opt_flags: flags of options, FW_OPT_*
+ * @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,
+ enum fw_opt opt_flags, 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);
+ list_add(&fw_priv->pending_list, &pending_fw_head);
+ mutex_unlock(&fw_lock);
+
+ if (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) {
+ 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
+ retval = -EAGAIN;
+ } else if (fw_priv->is_paged_buf && !fw_priv->data)
+ retval = -ENOMEM;
+
+ 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,
+ enum fw_opt 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, opt_flags, timeout);
+
+ if (!ret)
+ ret = assign_fw(firmware, device, opt_flags);
+
+out_unlock:
+ usermodehelper_read_unlock();
+
+ return ret;
+}
+
+static bool fw_force_sysfs_fallback(enum fw_opt 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(enum fw_opt 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))
+ return false;
+
+ /* Also permit LSMs and IMA to fail firmware sysfs fallback */
+ ret = security_kernel_load_data(LOADING_FIRMWARE);
+ if (ret < 0)
+ return ret;
+
+ 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
+ * @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 syfs
+ * loading interface. This syfs fallback mechanism may be disabled completely
+ * on a system by setting the proc sysctl value ignore_sysfs_fallback to true.
+ * If this false we check if the internal API caller set the @FW_OPT_NOFALLBACK
+ * flag, if so it would also disable the fallback mechanism. A system may want
+ * to enfoce 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,
+ enum fw_opt 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 syfs 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);
+}