1 files changed, 68 insertions, 0 deletions
diff --git a/drivers/firmware/efi/libstub/smbios.c b/drivers/firmware/efi/libstub/smbios.c
new file mode 100644
index 000000000000..f31410d7e7e1
--- /dev/null
+++ b/drivers/firmware/efi/libstub/smbios.c
@@ -0,0 +1,68 @@
+// SPDX-License-Identifier: GPL-2.0-only
+// Copyright 2022 Google LLC
+// Author: Ard Biesheuvel <ardb@google.com>
+
+#include <linux/efi.h>
+
+#include "efistub.h"
+
+typedef union efi_smbios_protocol efi_smbios_protocol_t;
+
+union efi_smbios_protocol {
+	struct {
+		efi_status_t (__efiapi *add)(efi_smbios_protocol_t *, efi_handle_t,
+					     u16 *, struct efi_smbios_record *);
+		efi_status_t (__efiapi *update_string)(efi_smbios_protocol_t *, u16 *,
+						       unsigned long *, u8 *);
+		efi_status_t (__efiapi *remove)(efi_smbios_protocol_t *, u16);
+		efi_status_t (__efiapi *get_next)(efi_smbios_protocol_t *, u16 *, u8 *,
+						  struct efi_smbios_record **,
+						  efi_handle_t *);
+
+		u8 major_version;
+		u8 minor_version;
+	};
+	struct {
+		u32 add;
+		u32 update_string;
+		u32 remove;
+		u32 get_next;
+
+		u8 major_version;
+		u8 minor_version;
+	} mixed_mode;
+};
+
+const struct efi_smbios_record *efi_get_smbios_record(u8 type)
+{
+	struct efi_smbios_record *record;
+	efi_smbios_protocol_t *smbios;
+	efi_status_t status;
+	u16 handle = 0xfffe;
+
+	status = efi_bs_call(locate_protocol, &EFI_SMBIOS_PROTOCOL_GUID, NULL,
+			     (void **)&smbios) ?:
+		 efi_call_proto(smbios, get_next, &handle, &type, &record, NULL);
+	if (status != EFI_SUCCESS)
+		return NULL;
+	return record;
+}
+
+const u8 *__efi_get_smbios_string(const struct efi_smbios_record *record,
+				  const u8 *offset)
+{
+	const u8 *strtable;
+
+	if (!record)
+		return NULL;
+
+	strtable = (u8 *)record + record->length;
+	for (int i = 1; i < *offset; i++) {
+		int len = strlen(strtable);
+
+		if (!len)
+			return NULL;
+		strtable += len + 1;
+	}
+	return strtable;
+}