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
efi_get_smbios_record(u8 type)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
__efi_get_smbios_string(const struct efi_smbios_record * record,const u8 * offset)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