diff --git a/include/efi_loader.h b/include/efi_loader.h
index 5d534e69bb..9c227005d1 100644
--- a/include/efi_loader.h
+++ b/include/efi_loader.h
@@ -558,6 +558,11 @@ struct efi_simple_file_system_protocol *efi_simple_file_system(
/* open file from device-path: */
struct efi_file_handle *efi_file_from_path(struct efi_device_path *fp);
+efi_status_t efi_file_size(struct efi_file_handle *fh, efi_uintn_t *size);
+
+/* get a device path from a Boot#### option */
+struct efi_device_path *efi_get_dp_from_boot(const efi_guid_t guid);
+
/**
* efi_size_in_pages() - convert size in bytes to size in pages
*
@@ -723,6 +728,8 @@ efi_status_t EFIAPI efi_query_variable_info(
u64 *remaining_variable_storage_size,
u64 *maximum_variable_size);
+void *efi_get_var(u16 *name, const efi_guid_t *vendor, efi_uintn_t *size);
+
/*
* See section 3.1.3 in the v2.7 UEFI spec for more details on
* the layout of EFI_LOAD_OPTION. In short it is:
diff --git a/lib/efi_loader/Makefile b/lib/efi_loader/Makefile
index 10b42e8847..da2741adec 100644
--- a/lib/efi_loader/Makefile
+++ b/lib/efi_loader/Makefile
@@ -23,6 +23,7 @@ endif
obj-$(CONFIG_CMD_BOOTEFI_HELLO) += helloworld_efi.o
obj-$(CONFIG_CMD_BOOTEFI_BOOTMGR) += efi_bootmgr.o
obj-y += efi_boottime.o
+obj-y += efi_helper.o
obj-$(CONFIG_EFI_HAVE_CAPSULE_SUPPORT) += efi_capsule.o
obj-$(CONFIG_EFI_CAPSULE_FIRMWARE) += efi_firmware.o
obj-y += efi_console.o
diff --git a/lib/efi_loader/efi_file.c b/lib/efi_loader/efi_file.c
index 8ece8e71ee..204105e25a 100644
--- a/lib/efi_loader/efi_file.c
+++ b/lib/efi_loader/efi_file.c
@@ -409,6 +409,45 @@ static efi_status_t efi_get_file_size(struct file_handle *fh,
return EFI_SUCCESS;
}
+/**
+ * efi_file_size() - Get the size of a file using an EFI file handle
+ *
+ * @fh: EFI file handle
+ * @size: buffer to fill in the discovered size
+ *
+ * Return: size of the file
+ */
+efi_status_t efi_file_size(struct efi_file_handle *fh, efi_uintn_t *size)
+{
+ struct efi_file_info *info = NULL;
+ efi_uintn_t bs = 0;
+ efi_status_t ret;
+
+ *size = 0;
+ ret = EFI_CALL(fh->getinfo(fh, (efi_guid_t *)&efi_file_info_guid, &bs,
+ info));
+ if (ret != EFI_BUFFER_TOO_SMALL) {
+ ret = EFI_DEVICE_ERROR;
+ goto out;
+ }
+
+ info = malloc(bs);
+ if (!info) {
+ ret = EFI_OUT_OF_RESOURCES;
+ goto out;
+ }
+ ret = EFI_CALL(fh->getinfo(fh, (efi_guid_t *)&efi_file_info_guid, &bs,
+ info));
+ if (ret != EFI_SUCCESS)
+ goto out;
+
+ *size = info->file_size;
+
+out:
+ free(info);
+ return ret;
+}
+
static efi_status_t file_read(struct file_handle *fh, u64 *buffer_size,
void *buffer)
{
diff --git a/lib/efi_loader/efi_helper.c b/lib/efi_loader/efi_helper.c
new file mode 100644
index 0000000000..d03a736461
--- /dev/null
+++ b/lib/efi_loader/efi_helper.c
@@ -0,0 +1,98 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (c) 2020, Linaro Limited
+ */
+
+#define LOG_CATEGORY LOGC_EFI
+#include <common.h>
+#include <env.h>
+#include <malloc.h>
+#include <dm.h>
+#include <fs.h>
+#include <efi_load_initrd.h>
+#include <efi_loader.h>
+#include <efi_variable.h>
+
+/**
+ * efi_create_current_boot_var() - Return Boot#### name were #### is replaced by
+ * the value of BootCurrent
+ *
+ * @var_name: variable name
+ * @var_name_size: size of var_name
+ *
+ * Return: Status code
+ */
+static efi_status_t efi_create_current_boot_var(u16 var_name[],
+ size_t var_name_size)
+{
+ efi_uintn_t boot_current_size;
+ efi_status_t ret;
+ u16 boot_current;
+ u16 *pos;
+
+ boot_current_size = sizeof(boot_current);
+ ret = efi_get_variable_int(L"BootCurrent",
+ &efi_global_variable_guid, NULL,
+ &boot_current_size, &boot_current, NULL);
+ if (ret != EFI_SUCCESS)
+ goto out;
+
+ pos = efi_create_indexed_name(var_name, var_name_size, "Boot",
+ boot_current);
+ if (!pos) {
+ ret = EFI_OUT_OF_RESOURCES;
+ goto out;
+ }
+
+out:
+ return ret;
+}
+
+/**
+ * efi_get_dp_from_boot() - Retrieve and return a device path from an EFI
+ * Boot### variable.
+ * A boot option may contain an array of device paths.
+ * We use a VenMedia() with a specific GUID to identify
+ * the usage of the array members. This function is
+ * used to extract a specific device path
+ *
+ * @guid: vendor GUID of the VenMedia() device path node identifying the
+ * device path
+ *
+ * Return: device path or NULL. Caller must free the returned value
+ */
+struct efi_device_path *efi_get_dp_from_boot(const efi_guid_t guid)
+{
+ struct efi_device_path *file_path = NULL;
+ struct efi_device_path *tmp = NULL;
+ struct efi_load_option lo;
+ void *var_value = NULL;
+ efi_uintn_t size;
+ efi_status_t ret;
+ u16 var_name[16];
+
+ ret = efi_create_current_boot_var(var_name, sizeof(var_name));
+ if (ret != EFI_SUCCESS)
+ return NULL;
+
+ var_value = efi_get_var(var_name, &efi_global_variable_guid, &size);
+ if (!var_value)
+ return NULL;
+
+ ret = efi_deserialize_load_option(&lo, var_value, &size);
+ if (ret != EFI_SUCCESS)
+ goto out;
+
+ tmp = efi_dp_from_lo(&lo, &size, guid);
+ if (!tmp)
+ goto out;
+
+ /* efi_dp_dup will just return NULL if efi_dp_next is NULL */
+ file_path = efi_dp_dup(efi_dp_next(tmp));
+
+out:
+ efi_free_pool(tmp);
+ free(var_value);
+
+ return file_path;
+}
diff --git a/lib/efi_loader/efi_var_common.c b/lib/efi_loader/efi_var_common.c
index 1c7459266a..b11ed91a74 100644
--- a/lib/efi_loader/efi_var_common.c
+++ b/lib/efi_loader/efi_var_common.c
@@ -9,6 +9,7 @@
#include <common.h>
#include <efi_loader.h>
#include <efi_variable.h>
+#include <stdlib.h>
enum efi_secure_mode {
EFI_MODE_SETUP,
@@ -343,3 +344,35 @@ enum efi_auth_var_type efi_auth_var_get_type(u16 *name, const efi_guid_t *guid)
}
return EFI_AUTH_VAR_NONE;
}
+
+/**
+ * efi_get_var() - read value of an EFI variable
+ *
+ * @name: variable name
+ * @start: vendor GUID
+ * @size: size of allocated buffer
+ *
+ * Return: buffer with variable data or NULL
+ */
+void *efi_get_var(u16 *name, const efi_guid_t *vendor, efi_uintn_t *size)
+{
+ efi_status_t ret;
+ void *buf = NULL;
+
+ *size = 0;
+ ret = efi_get_variable_int(name, vendor, NULL, size, buf, NULL);
+ if (ret == EFI_BUFFER_TOO_SMALL) {
+ buf = malloc(*size);
+ if (!buf)
+ return NULL;
+ ret = efi_get_variable_int(name, vendor, NULL, size, buf, NULL);
+ }
+
+ if (ret != EFI_SUCCESS) {
+ free(buf);
+ *size = 0;
+ return NULL;
+ }
+
+ return buf;
+}