efi: vars: Move efivar caching layer into efivarfs

Move the fiddly bits of the efivar layer into its only remaining user,
efivarfs, and confine its use to that particular module. All other uses
of the EFI variable store have no need for this additional layer of
complexity, given that they either only read variables, or read and
write variables into a separate GUIDed namespace, and cannot be used to
manipulate EFI variables that are covered by the EFI spec and/or affect
the boot flow.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

drivers/firmware/efi/efi.c

@@ -899,6 +899,7 @@ int efi_status_to_err(efi_status_t status)
 
 	return err;
 }
+EXPORT_SYMBOL_GPL(efi_status_to_err);
 
 static DEFINE_SPINLOCK(efi_mem_reserve_persistent_lock);
 static struct linux_efi_memreserve *efi_memreserve_root __ro_after_init;

fs/efivarfs/Makefile

@@ -5,4 +5,4 @@
 
 obj-$(CONFIG_EFIVAR_FS)		+= efivarfs.o
 
-efivarfs-objs			:= inode.o file.o super.o
+efivarfs-objs			:= inode.o file.o super.o vars.o

fs/efivarfs/internal.h

@@ -7,6 +7,46 @@
 #define EFIVAR_FS_INTERNAL_H
 
 #include <linux/list.h>
+#include <linux/efi.h>
+
+struct efi_variable {
+	efi_char16_t  VariableName[EFI_VAR_NAME_LEN/sizeof(efi_char16_t)];
+	efi_guid_t    VendorGuid;
+	unsigned long DataSize;
+	__u8          Data[1024];
+	efi_status_t  Status;
+	__u32         Attributes;
+} __attribute__((packed));
+
+struct efivar_entry {
+	struct efi_variable var;
+	struct list_head list;
+	struct kobject kobj;
+};
+
+int efivar_init(int (*func)(efi_char16_t *, efi_guid_t, unsigned long, void *),
+		void *data, bool duplicates, struct list_head *head);
+
+int efivar_entry_add(struct efivar_entry *entry, struct list_head *head);
+void __efivar_entry_add(struct efivar_entry *entry, struct list_head *head);
+void efivar_entry_remove(struct efivar_entry *entry);
+int efivar_entry_delete(struct efivar_entry *entry);
+
+int efivar_entry_size(struct efivar_entry *entry, unsigned long *size);
+int __efivar_entry_get(struct efivar_entry *entry, u32 *attributes,
+		       unsigned long *size, void *data);
+int efivar_entry_get(struct efivar_entry *entry, u32 *attributes,
+		     unsigned long *size, void *data);
+int efivar_entry_set_get_size(struct efivar_entry *entry, u32 attributes,
+			      unsigned long *size, void *data, bool *set);
+
+int efivar_entry_iter(int (*func)(struct efivar_entry *, void *),
+		      struct list_head *head, void *data);
+
+bool efivar_validate(efi_guid_t vendor, efi_char16_t *var_name, u8 *data,
+		     unsigned long data_size);
+bool efivar_variable_is_removable(efi_guid_t vendor, const char *name,
+				  size_t len);
 
 extern const struct file_operations efivarfs_file_operations;
 extern const struct inode_operations efivarfs_dir_inode_operations;

include/linux/efi.h

@@ -1030,21 +1030,6 @@ struct efivars {
 
 #define EFI_VAR_NAME_LEN	1024
 
-struct efi_variable {
-	efi_char16_t  VariableName[EFI_VAR_NAME_LEN/sizeof(efi_char16_t)];
-	efi_guid_t    VendorGuid;
-	unsigned long DataSize;
-	__u8          Data[1024];
-	efi_status_t  Status;
-	__u32         Attributes;
-} __attribute__((packed));
-
-struct efivar_entry {
-	struct efi_variable var;
-	struct list_head list;
-	struct kobject kobj;
-};
-
 int efivars_register(struct efivars *efivars,
 		     const struct efivar_operations *ops,
 		     struct kobject *kobject);
@@ -1052,29 +1037,6 @@ int efivars_unregister(struct efivars *efivars);
 struct kobject *efivars_kobject(void);
 
 int efivar_supports_writes(void);
-int efivar_init(int (*func)(efi_char16_t *, efi_guid_t, unsigned long, void *),
-		void *data, bool duplicates, struct list_head *head);
-
-int efivar_entry_add(struct efivar_entry *entry, struct list_head *head);
-void __efivar_entry_add(struct efivar_entry *entry, struct list_head *head);
-void efivar_entry_remove(struct efivar_entry *entry);
-int efivar_entry_delete(struct efivar_entry *entry);
-
-int efivar_entry_size(struct efivar_entry *entry, unsigned long *size);
-int __efivar_entry_get(struct efivar_entry *entry, u32 *attributes,
-		       unsigned long *size, void *data);
-int efivar_entry_get(struct efivar_entry *entry, u32 *attributes,
-		     unsigned long *size, void *data);
-int efivar_entry_set_get_size(struct efivar_entry *entry, u32 attributes,
-			      unsigned long *size, void *data, bool *set);
-
-int efivar_entry_iter(int (*func)(struct efivar_entry *, void *),
-		      struct list_head *head, void *data);
-
-bool efivar_validate(efi_guid_t vendor, efi_char16_t *var_name, u8 *data,
-		     unsigned long data_size);
-bool efivar_variable_is_removable(efi_guid_t vendor, const char *name,
-				  size_t len);
 
 int efivar_lock(void);
 int efivar_trylock(void);