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>

2 files changed, 44 insertions, 27 deletions

diff --git a/drivers/firmware/efivars.c b/drivers/firmware/efivars.c
index b10b7d7bd7de..ff0c373e3bbf 100644
--- a/drivers/firmware/efivars.c
+++ b/drivers/firmware/efivars.c
@@ -89,28 +89,6 @@ MODULE_DESCRIPTION("sysfs interface to EFI Variables");
 MODULE_LICENSE("GPL");
 MODULE_VERSION(EFIVARS_VERSION);
 
-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;
-};
-
 /*
  * The maximum size of VariableName + Data = 1024
  * Therefore, it's reasonable to save that much
@@ -706,7 +684,7 @@ out_free:
         return error;
 }
 
-static void unregister_efivars(struct efivars *efivars)
+void unregister_efivars(struct efivars *efivars)
 {
         struct efivar_entry *entry, *n;
 
@@ -724,10 +702,11 @@ static void unregister_efivars(struct efivars *efivars)
         kfree(efivars->del_var);
         kset_unregister(efivars->kset);
 }
+EXPORT_SYMBOL_GPL(unregister_efivars);
 
-static int register_efivars(struct efivars *efivars,
-                            const struct efivar_operations *ops,
-                            struct kobject *parent_kobj)
+int register_efivars(struct efivars *efivars,
+                     const struct efivar_operations *ops,
+                     struct kobject *parent_kobj)
 {
         efi_status_t status = EFI_NOT_FOUND;
         efi_guid_t vendor_guid;
@@ -789,6 +768,7 @@ out:
 
         return error;
 }
+EXPORT_SYMBOL_GPL(register_efivars);
 
 static struct efivars __efivars;
 static struct efivar_operations ops;
@@ -810,7 +790,7 @@ efivars_init(void)
                EFIVARS_DATE);
 
         if (!efi_enabled)
-                return -ENODEV;
+                return 0;
 
         /* For now we'll register the efi directory at /sys/firmware/efi */
         efi_kobj = kobject_create_and_add("efi", firmware_kobj);
diff --git a/include/linux/efi.h b/include/linux/efi.h
index fb737bc19a8c..33fa1203024e 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -397,4 +397,41 @@ static inline void memrange_efi_to_native(u64 *addr, u64 *npages)
         *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 */