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 union efi_smbios_protocol efi_smbios_protocol_t; 10 11 union efi_smbios_protocol { 12 struct { 13 efi_status_t (__efiapi *add)(efi_smbios_protocol_t *, efi_handle_t, 14 u16 *, struct efi_smbios_record *); 15 efi_status_t (__efiapi *update_string)(efi_smbios_protocol_t *, u16 *, 16 unsigned long *, u8 *); 17 efi_status_t (__efiapi *remove)(efi_smbios_protocol_t *, u16); 18 efi_status_t (__efiapi *get_next)(efi_smbios_protocol_t *, u16 *, u8 *, 19 struct efi_smbios_record **, 20 efi_handle_t *); 21 22 u8 major_version; 23 u8 minor_version; 24 }; 25 struct { 26 u32 add; 27 u32 update_string; 28 u32 remove; 29 u32 get_next; 30 31 u8 major_version; 32 u8 minor_version; 33 } mixed_mode; 34 }; 35 36 const struct efi_smbios_record *efi_get_smbios_record(u8 type) 37 { 38 struct efi_smbios_record *record; 39 efi_smbios_protocol_t *smbios; 40 efi_status_t status; 41 u16 handle = 0xfffe; 42 43 status = efi_bs_call(locate_protocol, &EFI_SMBIOS_PROTOCOL_GUID, NULL, 44 (void **)&smbios) ?: 45 efi_call_proto(smbios, get_next, &handle, &type, &record, NULL); 46 if (status != EFI_SUCCESS) 47 return NULL; 48 return record; 49 } 50 51 const u8 *__efi_get_smbios_string(const struct efi_smbios_record *record, 52 const u8 *offset) 53 { 54 const u8 *strtable; 55 56 if (!record) 57 return NULL; 58 59 strtable = (u8 *)record + record->length; 60 for (int i = 1; i < *offset; i++) { 61 int len = strlen(strtable); 62 63 if (!len) 64 return NULL; 65 strtable += len + 1; 66 } 67 return strtable; 68 } 69