efivars: Expose efivars functionality to external drivers.
Signed-off-by: Mike Waychison <mikew@google.com>
Cc: Matt Domsch <Matt_Domsch@dell.com>,
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/include/linux/efi.h b/include/linux/efi.h
index fb737bc..33fa120 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -397,4 +397,41 @@
*addr &= PAGE_MASK;
}
+#if defined(CONFIG_EFI_VARS) || defined(CONFIG_EFI_VARS_MODULE)
+/*
+ * EFI Variable support.
+ *
+ * Different firmware drivers can expose their EFI-like variables using
+ * the following.
+ */
+
+struct efivar_operations {
+ efi_get_variable_t *get_variable;
+ efi_get_next_variable_t *get_next_variable;
+ efi_set_variable_t *set_variable;
+};
+
+struct efivars {
+ /*
+ * ->lock protects two things:
+ * 1) ->list - adds, removals, reads, writes
+ * 2) ops.[gs]et_variable() calls.
+ * It must not be held when creating sysfs entries or calling kmalloc.
+ * ops.get_next_variable() is only called from register_efivars(),
+ * which is protected by the BKL, so that path is safe.
+ */
+ spinlock_t lock;
+ struct list_head list;
+ struct kset *kset;
+ struct bin_attribute *new_var, *del_var;
+ const struct efivar_operations *ops;
+};
+
+int register_efivars(struct efivars *efivars,
+ const struct efivar_operations *ops,
+ struct kobject *parent_kobj);
+void unregister_efivars(struct efivars *efivars);
+
+#endif /* CONFIG_EFI_VARS */
+
#endif /* _LINUX_EFI_H */