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