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-rw-r--r--drivers/firmware/efi/vars.c1049
1 files changed, 1049 insertions, 0 deletions
diff --git a/drivers/firmware/efi/vars.c b/drivers/firmware/efi/vars.c
new file mode 100644
index 000000000000..dd1c20a426fa
--- /dev/null
+++ b/drivers/firmware/efi/vars.c
@@ -0,0 +1,1049 @@
+/*
+ * Originally from efivars.c
+ *
+ * Copyright (C) 2001,2003,2004 Dell <Matt_Domsch@dell.com>
+ * Copyright (C) 2004 Intel Corporation <matthew.e.tolentino@intel.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include <linux/capability.h>
+#include <linux/types.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/string.h>
+#include <linux/smp.h>
+#include <linux/efi.h>
+#include <linux/sysfs.h>
+#include <linux/device.h>
+#include <linux/slab.h>
+#include <linux/ctype.h>
+
+/* Private pointer to registered efivars */
+static struct efivars *__efivars;
+
+static bool efivar_wq_enabled = true;
+DECLARE_WORK(efivar_work, NULL);
+EXPORT_SYMBOL_GPL(efivar_work);
+
+static bool
+validate_device_path(struct efi_variable *var, int match, u8 *buffer,
+ unsigned long len)
+{
+ struct efi_generic_dev_path *node;
+ int offset = 0;
+
+ node = (struct efi_generic_dev_path *)buffer;
+
+ if (len < sizeof(*node))
+ return false;
+
+ while (offset <= len - sizeof(*node) &&
+ node->length >= sizeof(*node) &&
+ node->length <= len - offset) {
+ offset += node->length;
+
+ if ((node->type == EFI_DEV_END_PATH ||
+ node->type == EFI_DEV_END_PATH2) &&
+ node->sub_type == EFI_DEV_END_ENTIRE)
+ return true;
+
+ node = (struct efi_generic_dev_path *)(buffer + offset);
+ }
+
+ /*
+ * If we're here then either node->length pointed past the end
+ * of the buffer or we reached the end of the buffer without
+ * finding a device path end node.
+ */
+ return false;
+}
+
+static bool
+validate_boot_order(struct efi_variable *var, int match, u8 *buffer,
+ unsigned long len)
+{
+ /* An array of 16-bit integers */
+ if ((len % 2) != 0)
+ return false;
+
+ return true;
+}
+
+static bool
+validate_load_option(struct efi_variable *var, int match, u8 *buffer,
+ unsigned long len)
+{
+ u16 filepathlength;
+ int i, desclength = 0, namelen;
+
+ namelen = utf16_strnlen(var->VariableName, sizeof(var->VariableName));
+
+ /* Either "Boot" or "Driver" followed by four digits of hex */
+ for (i = match; i < match+4; i++) {
+ if (var->VariableName[i] > 127 ||
+ hex_to_bin(var->VariableName[i] & 0xff) < 0)
+ return true;
+ }
+
+ /* Reject it if there's 4 digits of hex and then further content */
+ if (namelen > match + 4)
+ return false;
+
+ /* A valid entry must be at least 8 bytes */
+ if (len < 8)
+ return false;
+
+ filepathlength = buffer[4] | buffer[5] << 8;
+
+ /*
+ * There's no stored length for the description, so it has to be
+ * found by hand
+ */
+ desclength = utf16_strsize((efi_char16_t *)(buffer + 6), len - 6) + 2;
+
+ /* Each boot entry must have a descriptor */
+ if (!desclength)
+ return false;
+
+ /*
+ * If the sum of the length of the description, the claimed filepath
+ * length and the original header are greater than the length of the
+ * variable, it's malformed
+ */
+ if ((desclength + filepathlength + 6) > len)
+ return false;
+
+ /*
+ * And, finally, check the filepath
+ */
+ return validate_device_path(var, match, buffer + desclength + 6,
+ filepathlength);
+}
+
+static bool
+validate_uint16(struct efi_variable *var, int match, u8 *buffer,
+ unsigned long len)
+{
+ /* A single 16-bit integer */
+ if (len != 2)
+ return false;
+
+ return true;
+}
+
+static bool
+validate_ascii_string(struct efi_variable *var, int match, u8 *buffer,
+ unsigned long len)
+{
+ int i;
+
+ for (i = 0; i < len; i++) {
+ if (buffer[i] > 127)
+ return false;
+
+ if (buffer[i] == 0)
+ return true;
+ }
+
+ return false;
+}
+
+struct variable_validate {
+ char *name;
+ bool (*validate)(struct efi_variable *var, int match, u8 *data,
+ unsigned long len);
+};
+
+static const struct variable_validate variable_validate[] = {
+ { "BootNext", validate_uint16 },
+ { "BootOrder", validate_boot_order },
+ { "DriverOrder", validate_boot_order },
+ { "Boot*", validate_load_option },
+ { "Driver*", validate_load_option },
+ { "ConIn", validate_device_path },
+ { "ConInDev", validate_device_path },
+ { "ConOut", validate_device_path },
+ { "ConOutDev", validate_device_path },
+ { "ErrOut", validate_device_path },
+ { "ErrOutDev", validate_device_path },
+ { "Timeout", validate_uint16 },
+ { "Lang", validate_ascii_string },
+ { "PlatformLang", validate_ascii_string },
+ { "", NULL },
+};
+
+bool
+efivar_validate(struct efi_variable *var, u8 *data, unsigned long len)
+{
+ int i;
+ u16 *unicode_name = var->VariableName;
+
+ for (i = 0; variable_validate[i].validate != NULL; i++) {
+ const char *name = variable_validate[i].name;
+ int match;
+
+ for (match = 0; ; match++) {
+ char c = name[match];
+ u16 u = unicode_name[match];
+
+ /* All special variables are plain ascii */
+ if (u > 127)
+ return true;
+
+ /* Wildcard in the matching name means we've matched */
+ if (c == '*')
+ return variable_validate[i].validate(var,
+ match, data, len);
+
+ /* Case sensitive match */
+ if (c != u)
+ break;
+
+ /* Reached the end of the string while matching */
+ if (!c)
+ return variable_validate[i].validate(var,
+ match, data, len);
+ }
+ }
+
+ return true;
+}
+EXPORT_SYMBOL_GPL(efivar_validate);
+
+static efi_status_t
+check_var_size(u32 attributes, unsigned long size)
+{
+ u64 storage_size, remaining_size, max_size;
+ efi_status_t status;
+ const struct efivar_operations *fops = __efivars->ops;
+
+ if (!fops->query_variable_info)
+ return EFI_UNSUPPORTED;
+
+ status = fops->query_variable_info(attributes, &storage_size,
+ &remaining_size, &max_size);
+
+ if (status != EFI_SUCCESS)
+ return status;
+
+ if (!storage_size || size > remaining_size || size > max_size ||
+ (remaining_size - size) < (storage_size / 2))
+ return EFI_OUT_OF_RESOURCES;
+
+ return status;
+}
+
+static int efi_status_to_err(efi_status_t status)
+{
+ int err;
+
+ switch (status) {
+ case EFI_SUCCESS:
+ err = 0;
+ break;
+ case EFI_INVALID_PARAMETER:
+ err = -EINVAL;
+ break;
+ case EFI_OUT_OF_RESOURCES:
+ err = -ENOSPC;
+ break;
+ case EFI_DEVICE_ERROR:
+ err = -EIO;
+ break;
+ case EFI_WRITE_PROTECTED:
+ err = -EROFS;
+ break;
+ case EFI_SECURITY_VIOLATION:
+ err = -EACCES;
+ break;
+ case EFI_NOT_FOUND:
+ err = -ENOENT;
+ break;
+ default:
+ err = -EINVAL;
+ }
+
+ return err;
+}
+
+static bool variable_is_present(efi_char16_t *variable_name, efi_guid_t *vendor,
+ struct list_head *head)
+{
+ struct efivar_entry *entry, *n;
+ unsigned long strsize1, strsize2;
+ bool found = false;
+
+ strsize1 = utf16_strsize(variable_name, 1024);
+ list_for_each_entry_safe(entry, n, head, list) {
+ strsize2 = utf16_strsize(entry->var.VariableName, 1024);
+ if (strsize1 == strsize2 &&
+ !memcmp(variable_name, &(entry->var.VariableName),
+ strsize2) &&
+ !efi_guidcmp(entry->var.VendorGuid,
+ *vendor)) {
+ found = true;
+ break;
+ }
+ }
+ return found;
+}
+
+/*
+ * Returns the size of variable_name, in bytes, including the
+ * terminating NULL character, or variable_name_size if no NULL
+ * character is found among the first variable_name_size bytes.
+ */
+static unsigned long var_name_strnsize(efi_char16_t *variable_name,
+ unsigned long variable_name_size)
+{
+ unsigned long len;
+ efi_char16_t c;
+
+ /*
+ * The variable name is, by definition, a NULL-terminated
+ * string, so make absolutely sure that variable_name_size is
+ * the value we expect it to be. If not, return the real size.
+ */
+ for (len = 2; len <= variable_name_size; len += sizeof(c)) {
+ c = variable_name[(len / sizeof(c)) - 1];
+ if (!c)
+ break;
+ }
+
+ return min(len, variable_name_size);
+}
+
+/*
+ * Print a warning when duplicate EFI variables are encountered and
+ * disable the sysfs workqueue since the firmware is buggy.
+ */
+static void dup_variable_bug(efi_char16_t *s16, efi_guid_t *vendor_guid,
+ unsigned long len16)
+{
+ size_t i, len8 = len16 / sizeof(efi_char16_t);
+ char *s8;
+
+ /*
+ * Disable the workqueue since the algorithm it uses for
+ * detecting new variables won't work with this buggy
+ * implementation of GetNextVariableName().
+ */
+ efivar_wq_enabled = false;
+
+ s8 = kzalloc(len8, GFP_KERNEL);
+ if (!s8)
+ return;
+
+ for (i = 0; i < len8; i++)
+ s8[i] = s16[i];
+
+ printk(KERN_WARNING "efivars: duplicate variable: %s-%pUl\n",
+ s8, vendor_guid);
+ kfree(s8);
+}
+
+/**
+ * efivar_init - build the initial list of EFI variables
+ * @func: callback function to invoke for every variable
+ * @data: function-specific data to pass to @func
+ * @atomic: do we need to execute the @func-loop atomically?
+ * @duplicates: error if we encounter duplicates on @head?
+ * @head: initialised head of variable list
+ *
+ * Get every EFI variable from the firmware and invoke @func. @func
+ * should call efivar_entry_add() to build the list of variables.
+ *
+ * Returns 0 on success, or a kernel error code on failure.
+ */
+int efivar_init(int (*func)(efi_char16_t *, efi_guid_t, unsigned long, void *),
+ void *data, bool atomic, bool duplicates,
+ struct list_head *head)
+{
+ const struct efivar_operations *ops = __efivars->ops;
+ unsigned long variable_name_size = 1024;
+ efi_char16_t *variable_name;
+ efi_status_t status;
+ efi_guid_t vendor_guid;
+ int err = 0;
+
+ variable_name = kzalloc(variable_name_size, GFP_KERNEL);
+ if (!variable_name) {
+ printk(KERN_ERR "efivars: Memory allocation failed.\n");
+ return -ENOMEM;
+ }
+
+ spin_lock_irq(&__efivars->lock);
+
+ /*
+ * Per EFI spec, the maximum storage allocated for both
+ * the variable name and variable data is 1024 bytes.
+ */
+
+ do {
+ variable_name_size = 1024;
+
+ status = ops->get_next_variable(&variable_name_size,
+ variable_name,
+ &vendor_guid);
+ switch (status) {
+ case EFI_SUCCESS:
+ if (!atomic)
+ spin_unlock_irq(&__efivars->lock);
+
+ variable_name_size = var_name_strnsize(variable_name,
+ variable_name_size);
+
+ /*
+ * Some firmware implementations return the
+ * same variable name on multiple calls to
+ * get_next_variable(). Terminate the loop
+ * immediately as there is no guarantee that
+ * we'll ever see a different variable name,
+ * and may end up looping here forever.
+ */
+ if (duplicates &&
+ variable_is_present(variable_name, &vendor_guid, head)) {
+ dup_variable_bug(variable_name, &vendor_guid,
+ variable_name_size);
+ if (!atomic)
+ spin_lock_irq(&__efivars->lock);
+
+ status = EFI_NOT_FOUND;
+ break;
+ }
+
+ err = func(variable_name, vendor_guid, variable_name_size, data);
+ if (err)
+ status = EFI_NOT_FOUND;
+
+ if (!atomic)
+ spin_lock_irq(&__efivars->lock);
+
+ break;
+ case EFI_NOT_FOUND:
+ break;
+ default:
+ printk(KERN_WARNING "efivars: get_next_variable: status=%lx\n",
+ status);
+ status = EFI_NOT_FOUND;
+ break;
+ }
+
+ } while (status != EFI_NOT_FOUND);
+
+ spin_unlock_irq(&__efivars->lock);
+
+ kfree(variable_name);
+
+ return err;
+}
+EXPORT_SYMBOL_GPL(efivar_init);
+
+/**
+ * efivar_entry_add - add entry to variable list
+ * @entry: entry to add to list
+ * @head: list head
+ */
+void efivar_entry_add(struct efivar_entry *entry, struct list_head *head)
+{
+ spin_lock_irq(&__efivars->lock);
+ list_add(&entry->list, head);
+ spin_unlock_irq(&__efivars->lock);
+}
+EXPORT_SYMBOL_GPL(efivar_entry_add);
+
+/**
+ * efivar_entry_remove - remove entry from variable list
+ * @entry: entry to remove from list
+ */
+void efivar_entry_remove(struct efivar_entry *entry)
+{
+ spin_lock_irq(&__efivars->lock);
+ list_del(&entry->list);
+ spin_unlock_irq(&__efivars->lock);
+}
+EXPORT_SYMBOL_GPL(efivar_entry_remove);
+
+/*
+ * efivar_entry_list_del_unlock - remove entry from variable list
+ * @entry: entry to remove
+ *
+ * Remove @entry from the variable list and release the list lock.
+ *
+ * NOTE: slightly weird locking semantics here - we expect to be
+ * called with the efivars lock already held, and we release it before
+ * returning. This is because this function is usually called after
+ * set_variable() while the lock is still held.
+ */
+static void efivar_entry_list_del_unlock(struct efivar_entry *entry)
+{
+ WARN_ON(!spin_is_locked(&__efivars->lock));
+
+ list_del(&entry->list);
+ spin_unlock_irq(&__efivars->lock);
+}
+
+/**
+ * __efivar_entry_delete - delete an EFI variable
+ * @entry: entry containing EFI variable to delete
+ *
+ * Delete the variable from the firmware but leave @entry on the
+ * variable list.
+ *
+ * This function differs from efivar_entry_delete() because it does
+ * not remove @entry from the variable list. Also, it is safe to be
+ * called from within a efivar_entry_iter_begin() and
+ * efivar_entry_iter_end() region, unlike efivar_entry_delete().
+ *
+ * Returns 0 on success, or a converted EFI status code if
+ * set_variable() fails.
+ */
+int __efivar_entry_delete(struct efivar_entry *entry)
+{
+ const struct efivar_operations *ops = __efivars->ops;
+ efi_status_t status;
+
+ WARN_ON(!spin_is_locked(&__efivars->lock));
+
+ status = ops->set_variable(entry->var.VariableName,
+ &entry->var.VendorGuid,
+ 0, 0, NULL);
+
+ return efi_status_to_err(status);
+}
+EXPORT_SYMBOL_GPL(__efivar_entry_delete);
+
+/**
+ * efivar_entry_delete - delete variable and remove entry from list
+ * @entry: entry containing variable to delete
+ *
+ * Delete the variable from the firmware and remove @entry from the
+ * variable list. It is the caller's responsibility to free @entry
+ * once we return.
+ *
+ * Returns 0 on success, or a converted EFI status code if
+ * set_variable() fails.
+ */
+int efivar_entry_delete(struct efivar_entry *entry)
+{
+ const struct efivar_operations *ops = __efivars->ops;
+ efi_status_t status;
+
+ spin_lock_irq(&__efivars->lock);
+ status = ops->set_variable(entry->var.VariableName,
+ &entry->var.VendorGuid,
+ 0, 0, NULL);
+ if (!(status == EFI_SUCCESS || status == EFI_NOT_FOUND)) {
+ spin_unlock_irq(&__efivars->lock);
+ return efi_status_to_err(status);
+ }
+
+ efivar_entry_list_del_unlock(entry);
+ return 0;
+}
+EXPORT_SYMBOL_GPL(efivar_entry_delete);
+
+/**
+ * efivar_entry_set - call set_variable()
+ * @entry: entry containing the EFI variable to write
+ * @attributes: variable attributes
+ * @size: size of @data buffer
+ * @data: buffer containing variable data
+ * @head: head of variable list
+ *
+ * Calls set_variable() for an EFI variable. If creating a new EFI
+ * variable, this function is usually followed by efivar_entry_add().
+ *
+ * Before writing the variable, the remaining EFI variable storage
+ * space is checked to ensure there is enough room available.
+ *
+ * If @head is not NULL a lookup is performed to determine whether
+ * the entry is already on the list.
+ *
+ * Returns 0 on success, -EEXIST if a lookup is performed and the entry
+ * already exists on the list, or a converted EFI status code if
+ * set_variable() fails.
+ */
+int efivar_entry_set(struct efivar_entry *entry, u32 attributes,
+ unsigned long size, void *data, struct list_head *head)
+{
+ const struct efivar_operations *ops = __efivars->ops;
+ efi_status_t status;
+ efi_char16_t *name = entry->var.VariableName;
+ efi_guid_t vendor = entry->var.VendorGuid;
+
+ spin_lock_irq(&__efivars->lock);
+
+ if (head && efivar_entry_find(name, vendor, head, false)) {
+ spin_unlock_irq(&__efivars->lock);
+ return -EEXIST;
+ }
+
+ status = check_var_size(attributes, size + utf16_strsize(name, 1024));
+ if (status == EFI_SUCCESS || status == EFI_UNSUPPORTED)
+ status = ops->set_variable(name, &vendor,
+ attributes, size, data);
+
+ spin_unlock_irq(&__efivars->lock);
+
+ return efi_status_to_err(status);
+
+}
+EXPORT_SYMBOL_GPL(efivar_entry_set);
+
+/**
+ * efivar_entry_set_safe - call set_variable() if enough space in firmware
+ * @name: buffer containing the variable name
+ * @vendor: variable vendor guid
+ * @attributes: variable attributes
+ * @block: can we block in this context?
+ * @size: size of @data buffer
+ * @data: buffer containing variable data
+ *
+ * Ensures there is enough free storage in the firmware for this variable, and
+ * if so, calls set_variable(). If creating a new EFI variable, this function
+ * is usually followed by efivar_entry_add().
+ *
+ * Returns 0 on success, -ENOSPC if the firmware does not have enough
+ * space for set_variable() to succeed, or a converted EFI status code
+ * if set_variable() fails.
+ */
+int efivar_entry_set_safe(efi_char16_t *name, efi_guid_t vendor, u32 attributes,
+ bool block, unsigned long size, void *data)
+{
+ const struct efivar_operations *ops = __efivars->ops;
+ unsigned long flags;
+ efi_status_t status;
+
+ if (!ops->query_variable_info)
+ return -ENOSYS;
+
+ if (!block && spin_trylock_irqsave(&__efivars->lock, flags))
+ return -EBUSY;
+ else
+ spin_lock_irqsave(&__efivars->lock, flags);
+
+ status = check_var_size(attributes, size + utf16_strsize(name, 1024));
+ if (status != EFI_SUCCESS) {
+ spin_unlock_irqrestore(&__efivars->lock, flags);
+ return -ENOSPC;
+ }
+
+ status = ops->set_variable(name, &vendor, attributes, size, data);
+
+ spin_unlock_irqrestore(&__efivars->lock, flags);
+
+ return efi_status_to_err(status);
+}
+EXPORT_SYMBOL_GPL(efivar_entry_set_safe);
+
+/**
+ * efivar_entry_find - search for an entry
+ * @name: the EFI variable name
+ * @guid: the EFI variable vendor's guid
+ * @head: head of the variable list
+ * @remove: should we remove the entry from the list?
+ *
+ * Search for an entry on the variable list that has the EFI variable
+ * name @name and vendor guid @guid. If an entry is found on the list
+ * and @remove is true, the entry is removed from the list.
+ *
+ * The caller MUST call efivar_entry_iter_begin() and
+ * efivar_entry_iter_end() before and after the invocation of this
+ * function, respectively.
+ *
+ * Returns the entry if found on the list, %NULL otherwise.
+ */
+struct efivar_entry *efivar_entry_find(efi_char16_t *name, efi_guid_t guid,
+ struct list_head *head, bool remove)
+{
+ struct efivar_entry *entry, *n;
+ int strsize1, strsize2;
+ bool found = false;
+
+ WARN_ON(!spin_is_locked(&__efivars->lock));
+
+ list_for_each_entry_safe(entry, n, head, list) {
+ strsize1 = utf16_strsize(name, 1024);
+ strsize2 = utf16_strsize(entry->var.VariableName, 1024);
+ if (strsize1 == strsize2 &&
+ !memcmp(name, &(entry->var.VariableName), strsize1) &&
+ !efi_guidcmp(guid, entry->var.VendorGuid)) {
+ found = true;
+ break;
+ }
+ }
+
+ if (!found)
+ return NULL;
+
+ if (remove)
+ list_del(&entry->list);
+
+ return entry;
+}
+EXPORT_SYMBOL_GPL(efivar_entry_find);
+
+/**
+ * __efivar_entry_size - obtain the size of a variable
+ * @entry: entry for this variable
+ * @size: location to store the variable's size
+ *
+ * The caller MUST call efivar_entry_iter_begin() and
+ * efivar_entry_iter_end() before and after the invocation of this
+ * function, respectively.
+ */
+int __efivar_entry_size(struct efivar_entry *entry, unsigned long *size)
+{
+ const struct efivar_operations *ops = __efivars->ops;
+ efi_status_t status;
+
+ WARN_ON(!spin_is_locked(&__efivars->lock));
+
+ *size = 0;
+ status = ops->get_variable(entry->var.VariableName,
+ &entry->var.VendorGuid, NULL, size, NULL);
+ if (status != EFI_BUFFER_TOO_SMALL)
+ return efi_status_to_err(status);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(__efivar_entry_size);
+
+/**
+ * efivar_entry_size - obtain the size of a variable
+ * @entry: entry for this variable
+ * @size: location to store the variable's size
+ */
+int efivar_entry_size(struct efivar_entry *entry, unsigned long *size)
+{
+ const struct efivar_operations *ops = __efivars->ops;
+ efi_status_t status;
+
+ *size = 0;
+
+ spin_lock_irq(&__efivars->lock);
+ status = ops->get_variable(entry->var.VariableName,
+ &entry->var.VendorGuid, NULL, size, NULL);
+ spin_unlock_irq(&__efivars->lock);
+
+ if (status != EFI_BUFFER_TOO_SMALL)
+ return efi_status_to_err(status);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(efivar_entry_size);
+
+/**
+ * efivar_entry_get - call get_variable()
+ * @entry: read data for this variable
+ * @attributes: variable attributes
+ * @size: size of @data buffer
+ * @data: buffer to store variable data
+ */
+int efivar_entry_get(struct efivar_entry *entry, u32 *attributes,
+ unsigned long *size, void *data)
+{
+ const struct efivar_operations *ops = __efivars->ops;
+ efi_status_t status;
+
+ spin_lock_irq(&__efivars->lock);
+ status = ops->get_variable(entry->var.VariableName,
+ &entry->var.VendorGuid,
+ attributes, size, data);
+ spin_unlock_irq(&__efivars->lock);
+
+ return efi_status_to_err(status);
+}
+EXPORT_SYMBOL_GPL(efivar_entry_get);
+
+/**
+ * efivar_entry_set_get_size - call set_variable() and get new size (atomic)
+ * @entry: entry containing variable to set and get
+ * @attributes: attributes of variable to be written
+ * @size: size of data buffer
+ * @data: buffer containing data to write
+ * @set: did the set_variable() call succeed?
+ *
+ * This is a pretty special (complex) function. See efivarfs_file_write().
+ *
+ * Atomically call set_variable() for @entry and if the call is
+ * successful, return the new size of the variable from get_variable()
+ * in @size. The success of set_variable() is indicated by @set.
+ *
+ * Returns 0 on success, -EINVAL if the variable data is invalid,
+ * -ENOSPC if the firmware does not have enough available space, or a
+ * converted EFI status code if either of set_variable() or
+ * get_variable() fail.
+ *
+ * If the EFI variable does not exist when calling set_variable()
+ * (EFI_NOT_FOUND), @entry is removed from the variable list.
+ */
+int efivar_entry_set_get_size(struct efivar_entry *entry, u32 attributes,
+ unsigned long *size, void *data, bool *set)
+{
+ const struct efivar_operations *ops = __efivars->ops;
+ efi_char16_t *name = entry->var.VariableName;
+ efi_guid_t *vendor = &entry->var.VendorGuid;
+ efi_status_t status;
+ int err;
+
+ *set = false;
+
+ if (efivar_validate(&entry->var, data, *size) == false)
+ return -EINVAL;
+
+ /*
+ * The lock here protects the get_variable call, the conditional
+ * set_variable call, and removal of the variable from the efivars
+ * list (in the case of an authenticated delete).
+ */
+ spin_lock_irq(&__efivars->lock);
+
+ /*
+ * Ensure that the available space hasn't shrunk below the safe level
+ */
+ status = check_var_size(attributes, *size + utf16_strsize(name, 1024));
+ if (status != EFI_SUCCESS) {
+ if (status != EFI_UNSUPPORTED) {
+ err = efi_status_to_err(status);
+ goto out;
+ }
+
+ if (*size > 65536) {
+ err = -ENOSPC;
+ goto out;
+ }
+ }
+
+ status = ops->set_variable(name, vendor, attributes, *size, data);
+ if (status != EFI_SUCCESS) {
+ err = efi_status_to_err(status);
+ goto out;
+ }
+
+ *set = true;
+
+ /*
+ * Writing to the variable may have caused a change in size (which
+ * could either be an append or an overwrite), or the variable to be
+ * deleted. Perform a GetVariable() so we can tell what actually
+ * happened.
+ */
+ *size = 0;
+ status = ops->get_variable(entry->var.VariableName,
+ &entry->var.VendorGuid,
+ NULL, size, NULL);
+
+ if (status == EFI_NOT_FOUND)
+ efivar_entry_list_del_unlock(entry);
+ else
+ spin_unlock_irq(&__efivars->lock);
+
+ if (status && status != EFI_BUFFER_TOO_SMALL)
+ return efi_status_to_err(status);
+
+ return 0;
+
+out:
+ spin_unlock_irq(&__efivars->lock);
+ return err;
+
+}
+EXPORT_SYMBOL_GPL(efivar_entry_set_get_size);
+
+/**
+ * efivar_entry_iter_begin - begin iterating the variable list
+ *
+ * Lock the variable list to prevent entry insertion and removal until
+ * efivar_entry_iter_end() is called. This function is usually used in
+ * conjunction with __efivar_entry_iter() or efivar_entry_iter().
+ */
+void efivar_entry_iter_begin(void)
+{
+ spin_lock_irq(&__efivars->lock);
+}
+EXPORT_SYMBOL_GPL(efivar_entry_iter_begin);
+
+/**
+ * efivar_entry_iter_end - finish iterating the variable list
+ *
+ * Unlock the variable list and allow modifications to the list again.
+ */
+void efivar_entry_iter_end(void)
+{
+ spin_unlock_irq(&__efivars->lock);
+}
+EXPORT_SYMBOL_GPL(efivar_entry_iter_end);
+
+/**
+ * __efivar_entry_iter - iterate over variable list
+ * @func: callback function
+ * @head: head of the variable list
+ * @data: function-specific data to pass to callback
+ * @prev: entry to begin iterating from
+ *
+ * Iterate over the list of EFI variables and call @func with every
+ * entry on the list. It is safe for @func to remove entries in the
+ * list via efivar_entry_delete().
+ *
+ * You MUST call efivar_enter_iter_begin() before this function, and
+ * efivar_entry_iter_end() afterwards.
+ *
+ * It is possible to begin iteration from an arbitrary entry within
+ * the list by passing @prev. @prev is updated on return to point to
+ * the last entry passed to @func. To begin iterating from the
+ * beginning of the list @prev must be %NULL.
+ *
+ * The restrictions for @func are the same as documented for
+ * efivar_entry_iter().
+ */
+int __efivar_entry_iter(int (*func)(struct efivar_entry *, void *),
+ struct list_head *head, void *data,
+ struct efivar_entry **prev)
+{
+ struct efivar_entry *entry, *n;
+ int err = 0;
+
+ if (!prev || !*prev) {
+ list_for_each_entry_safe(entry, n, head, list) {
+ err = func(entry, data);
+ if (err)
+ break;
+ }
+
+ if (prev)
+ *prev = entry;
+
+ return err;
+ }
+
+
+ list_for_each_entry_safe_continue((*prev), n, head, list) {
+ err = func(*prev, data);
+ if (err)
+ break;
+ }
+
+ return err;
+}
+EXPORT_SYMBOL_GPL(__efivar_entry_iter);
+
+/**
+ * efivar_entry_iter - iterate over variable list
+ * @func: callback function
+ * @head: head of variable list
+ * @data: function-specific data to pass to callback
+ *
+ * Iterate over the list of EFI variables and call @func with every
+ * entry on the list. It is safe for @func to remove entries in the
+ * list via efivar_entry_delete() while iterating.
+ *
+ * Some notes for the callback function:
+ * - a non-zero return value indicates an error and terminates the loop
+ * - @func is called from atomic context
+ */
+int efivar_entry_iter(int (*func)(struct efivar_entry *, void *),
+ struct list_head *head, void *data)
+{
+ int err = 0;
+
+ efivar_entry_iter_begin();
+ err = __efivar_entry_iter(func, head, data, NULL);
+ efivar_entry_iter_end();
+
+ return err;
+}
+EXPORT_SYMBOL_GPL(efivar_entry_iter);
+
+/**
+ * efivars_kobject - get the kobject for the registered efivars
+ *
+ * If efivars_register() has not been called we return NULL,
+ * otherwise return the kobject used at registration time.
+ */
+struct kobject *efivars_kobject(void)
+{
+ if (!__efivars)
+ return NULL;
+
+ return __efivars->kobject;
+}
+EXPORT_SYMBOL_GPL(efivars_kobject);
+
+/**
+ * efivar_run_worker - schedule the efivar worker thread
+ */
+void efivar_run_worker(void)
+{
+ if (efivar_wq_enabled)
+ schedule_work(&efivar_work);
+}
+EXPORT_SYMBOL_GPL(efivar_run_worker);
+
+/**
+ * efivars_register - register an efivars
+ * @efivars: efivars to register
+ * @ops: efivars operations
+ * @kobject: @efivars-specific kobject
+ *
+ * Only a single efivars can be registered at any time.
+ */
+int efivars_register(struct efivars *efivars,
+ const struct efivar_operations *ops,
+ struct kobject *kobject)
+{
+ spin_lock_init(&efivars->lock);
+ efivars->ops = ops;
+ efivars->kobject = kobject;
+
+ __efivars = efivars;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(efivars_register);
+
+/**
+ * efivars_unregister - unregister an efivars
+ * @efivars: efivars to unregister
+ *
+ * The caller must have already removed every entry from the list,
+ * failure to do so is an error.
+ */
+int efivars_unregister(struct efivars *efivars)
+{
+ int rv;
+
+ if (!__efivars) {
+ printk(KERN_ERR "efivars not registered\n");
+ rv = -EINVAL;
+ goto out;
+ }
+
+ if (__efivars != efivars) {
+ rv = -EINVAL;
+ goto out;
+ }
+
+ __efivars = NULL;
+
+ rv = 0;
+out:
+ return rv;
+}
+EXPORT_SYMBOL_GPL(efivars_unregister);
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-27 07:56:22 +0000