1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright (C) 2005 IBM Corporation
4 *
5 * Authors:
6 * Seiji Munetoh <[email protected]>
7 * Stefan Berger <[email protected]>
8 * Reiner Sailer <[email protected]>
9 * Kylene Hall <[email protected]>
10 * Nayna Jain <[email protected]>
11 *
12 * Maintained by: <[email protected]>
13 *
14 * Access to the event log extended by the TCG BIOS of PC platform
15 */
16
17 #include <linux/device.h>
18 #include <linux/seq_file.h>
19 #include <linux/fs.h>
20 #include <linux/security.h>
21 #include <linux/module.h>
22 #include <linux/slab.h>
23 #include <linux/acpi.h>
24 #include <linux/tpm_eventlog.h>
25
26 #include "../tpm.h"
27 #include "common.h"
28
29 struct acpi_tcpa {
30 struct acpi_table_header hdr;
31 u16 platform_class;
32 union {
33 struct client_hdr {
34 u32 log_max_len __packed;
35 u64 log_start_addr __packed;
36 } client;
37 struct server_hdr {
38 u16 reserved;
39 u64 log_max_len __packed;
40 u64 log_start_addr __packed;
41 } server;
42 };
43 };
44
45 /* Check that the given log is indeed a TPM2 log. */
tpm_is_tpm2_log(void * bios_event_log,u64 len)46 static bool tpm_is_tpm2_log(void *bios_event_log, u64 len)
47 {
48 struct tcg_efi_specid_event_head *efispecid;
49 struct tcg_pcr_event *event_header;
50 int n;
51
52 if (len < sizeof(*event_header))
53 return false;
54 len -= sizeof(*event_header);
55 event_header = bios_event_log;
56
57 if (len < sizeof(*efispecid))
58 return false;
59 efispecid = (struct tcg_efi_specid_event_head *)event_header->event;
60
61 n = memcmp(efispecid->signature, TCG_SPECID_SIG,
62 sizeof(TCG_SPECID_SIG));
63 return n == 0;
64 }
65
tpm_bios_log_free(void * data)66 static void tpm_bios_log_free(void *data)
67 {
68 kvfree(data);
69 }
70
71 /* read binary bios log */
tpm_read_log_acpi(struct tpm_chip * chip)72 int tpm_read_log_acpi(struct tpm_chip *chip)
73 {
74 struct acpi_tcpa *buff;
75 acpi_status status;
76 void __iomem *virt;
77 u64 len, start;
78 struct tpm_bios_log *log;
79 struct acpi_table_tpm2 *tbl;
80 struct acpi_tpm2_phy *tpm2_phy;
81 int format;
82 int ret;
83
84 log = &chip->log;
85
86 /* Unfortuntely ACPI does not associate the event log with a specific
87 * TPM, like PPI. Thus all ACPI TPMs will read the same log.
88 */
89 if (!chip->acpi_dev_handle)
90 return -ENODEV;
91
92 if (chip->flags & TPM_CHIP_FLAG_TPM2) {
93 status = acpi_get_table("TPM2", 1,
94 (struct acpi_table_header **)&tbl);
95 if (ACPI_FAILURE(status))
96 return -ENODEV;
97
98 if (tbl->header.length <
99 sizeof(*tbl) + sizeof(struct acpi_tpm2_phy)) {
100 acpi_put_table((struct acpi_table_header *)tbl);
101 return -ENODEV;
102 }
103
104 tpm2_phy = (void *)tbl + sizeof(*tbl);
105 len = tpm2_phy->log_area_minimum_length;
106
107 start = tpm2_phy->log_area_start_address;
108 if (!start || !len) {
109 acpi_put_table((struct acpi_table_header *)tbl);
110 return -ENODEV;
111 }
112
113 acpi_put_table((struct acpi_table_header *)tbl);
114 format = EFI_TCG2_EVENT_LOG_FORMAT_TCG_2;
115 } else {
116 /* Find TCPA entry in RSDT (ACPI_LOGICAL_ADDRESSING) */
117 status = acpi_get_table(ACPI_SIG_TCPA, 1,
118 (struct acpi_table_header **)&buff);
119 if (ACPI_FAILURE(status))
120 return -ENODEV;
121
122 switch (buff->platform_class) {
123 case BIOS_SERVER:
124 len = buff->server.log_max_len;
125 start = buff->server.log_start_addr;
126 break;
127 case BIOS_CLIENT:
128 default:
129 len = buff->client.log_max_len;
130 start = buff->client.log_start_addr;
131 break;
132 }
133
134 acpi_put_table((struct acpi_table_header *)buff);
135 format = EFI_TCG2_EVENT_LOG_FORMAT_TCG_1_2;
136 }
137
138 if (!len) {
139 dev_warn(&chip->dev, "%s: TCPA log area empty\n", __func__);
140 return -EIO;
141 }
142
143 /* malloc EventLog space */
144 log->bios_event_log = kvmalloc(len, GFP_KERNEL);
145 if (!log->bios_event_log)
146 return -ENOMEM;
147
148 log->bios_event_log_end = log->bios_event_log + len;
149
150 virt = acpi_os_map_iomem(start, len);
151 if (!virt) {
152 dev_warn(&chip->dev, "%s: Failed to map ACPI memory\n", __func__);
153 /* try EFI log next */
154 ret = -ENODEV;
155 goto err;
156 }
157
158 memcpy_fromio(log->bios_event_log, virt, len);
159
160 acpi_os_unmap_iomem(virt, len);
161
162 if (chip->flags & TPM_CHIP_FLAG_TPM2 &&
163 !tpm_is_tpm2_log(log->bios_event_log, len)) {
164 /* try EFI log next */
165 ret = -ENODEV;
166 goto err;
167 }
168
169 ret = devm_add_action(&chip->dev, tpm_bios_log_free, log->bios_event_log);
170 if (ret) {
171 log->bios_event_log = NULL;
172 goto err;
173 }
174
175 return format;
176
177 err:
178 tpm_bios_log_free(log->bios_event_log);
179 log->bios_event_log = NULL;
180 return ret;
181 }
182