efi_loader: prepare for read only OP-TEE variables
We currently have two implementations of UEFI variables:
* variables provided via an OP-TEE module
* variables stored in the U-Boot environment
Read only variables are up to now only implemented in the U-Boot
environment implementation.
Provide a common interface for both implementations that allows handling
read-only variables.
As variable access is limited to very few source files put variable
related definitions into new include efi_variable.h instead of efi_loader.
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
diff --git a/include/efi_variable.h b/include/efi_variable.h
new file mode 100644
index 0000000..6789118
--- /dev/null
+++ b/include/efi_variable.h
@@ -0,0 +1,43 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Copyright (c) 2020, Heinrich Schuchardt <xypron.glpk@gmx.de>
+ */
+
+#ifndef _EFI_VARIABLE_H
+#define _EFI_VARIABLE_H
+
+#include <linux/bitops.h>
+
+#define EFI_VARIABLE_READ_ONLY BIT(31)
+
+/**
+ * efi_get_variable() - retrieve value of a UEFI variable
+ *
+ * @variable_name: name of the variable
+ * @vendor: vendor GUID
+ * @attributes: attributes of the variable
+ * @data_size: size of the buffer to which the variable value is copied
+ * @data: buffer to which the variable value is copied
+ * @timep: authentication time (seconds since start of epoch)
+ * Return: status code
+ */
+efi_status_t efi_get_variable_int(u16 *variable_name, const efi_guid_t *vendor,
+ u32 *attributes, efi_uintn_t *data_size,
+ void *data, u64 *timep);
+
+/**
+ * efi_set_variable() - set value of a UEFI variable
+ *
+ * @variable_name: name of the variable
+ * @vendor: vendor GUID
+ * @attributes: attributes of the variable
+ * @data_size: size of the buffer with the variable value
+ * @data: buffer with the variable value
+ * @ro_check: check the read only read only bit in attributes
+ * Return: status code
+ */
+efi_status_t efi_set_variable_int(u16 *variable_name, const efi_guid_t *vendor,
+ u32 attributes, efi_uintn_t data_size,
+ const void *data, bool ro_check);
+
+#endif