1 // SPDX-License-Identifier: GPL-2.0-only 2 // Copyright 2022 Google LLC 3 // Author: Ard Biesheuvel <ardb@google.com> 4 5 #include <linux/efi.h> 6 7 #include "efistub.h" 8 9 typedef struct efi_smbios_protocol efi_smbios_protocol_t; 10 11 struct efi_smbios_protocol { 12 efi_status_t (__efiapi *add)(efi_smbios_protocol_t *, efi_handle_t, 13 u16 *, struct efi_smbios_record *); 14 efi_status_t (__efiapi *update_string)(efi_smbios_protocol_t *, u16 *, 15 unsigned long *, u8 *); 16 efi_status_t (__efiapi *remove)(efi_smbios_protocol_t *, u16); 17 efi_status_t (__efiapi *get_next)(efi_smbios_protocol_t *, u16 *, u8 *, 18 struct efi_smbios_record **, 19 efi_handle_t *); 20 21 u8 major_version; 22 u8 minor_version; 23 }; 24 25 const struct efi_smbios_record *efi_get_smbios_record(u8 type) 26 { 27 struct efi_smbios_record *record; 28 efi_smbios_protocol_t *smbios; 29 efi_status_t status; 30 u16 handle = 0xfffe; 31 32 status = efi_bs_call(locate_protocol, &EFI_SMBIOS_PROTOCOL_GUID, NULL, 33 (void **)&smbios) ?: 34 efi_call_proto(smbios, get_next, &handle, &type, &record, NULL); 35 if (status != EFI_SUCCESS) 36 return NULL; 37 return record; 38 } 39 40 const u8 *__efi_get_smbios_string(const struct efi_smbios_record *record, 41 u8 type, int offset) 42 { 43 const u8 *strtable; 44 45 if (!record) 46 return NULL; 47 48 strtable = (u8 *)record + record->length; 49 for (int i = 1; i < ((u8 *)record)[offset]; i++) { 50 int len = strlen(strtable); 51 52 if (!len) 53 return NULL; 54 strtable += len + 1; 55 } 56 return strtable; 57 } 58