1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Copyright (C) 2017 Google
4 *
5 * Authors:
6 *      Thiebaud Weksteen <tweek@google.com>
7 */
8
9#include <linux/device.h>
10#include <linux/efi.h>
11#include <linux/tpm_eventlog.h>
12
13#include "../tpm.h"
14#include "common.h"
15
16/* read binary bios log from EFI configuration table */
17int tpm_read_log_efi(struct tpm_chip *chip)
18{
19
20	struct efi_tcg2_final_events_table *final_tbl = NULL;
21	int final_events_log_size = efi_tpm_final_log_size;
22	struct linux_efi_tpm_eventlog *log_tbl;
23	struct tpm_bios_log *log;
24	u32 log_size;
25	u8 tpm_log_version;
26	void *tmp;
27	int ret;
28
29	if (!(chip->flags & TPM_CHIP_FLAG_TPM2))
30		return -ENODEV;
31
32	if (efi.tpm_log == EFI_INVALID_TABLE_ADDR)
33		return -ENODEV;
34
35	log = &chip->log;
36
37	log_tbl = memremap(efi.tpm_log, sizeof(*log_tbl), MEMREMAP_WB);
38	if (!log_tbl) {
39		pr_err("Could not map UEFI TPM log table !\n");
40		return -ENOMEM;
41	}
42
43	log_size = log_tbl->size;
44	memunmap(log_tbl);
45
46	if (!log_size) {
47		pr_warn("UEFI TPM log area empty\n");
48		return -EIO;
49	}
50
51	log_tbl = memremap(efi.tpm_log, sizeof(*log_tbl) + log_size,
52			   MEMREMAP_WB);
53	if (!log_tbl) {
54		pr_err("Could not map UEFI TPM log table payload!\n");
55		return -ENOMEM;
56	}
57
58	/* malloc EventLog space */
59	log->bios_event_log = devm_kmemdup(&chip->dev, log_tbl->log, log_size, GFP_KERNEL);
60	if (!log->bios_event_log) {
61		ret = -ENOMEM;
62		goto out;
63	}
64
65	log->bios_event_log_end = log->bios_event_log + log_size;
66	tpm_log_version = log_tbl->version;
67
68	ret = tpm_log_version;
69
70	if (efi.tpm_final_log == EFI_INVALID_TABLE_ADDR ||
71	    final_events_log_size == 0 ||
72	    tpm_log_version != EFI_TCG2_EVENT_LOG_FORMAT_TCG_2)
73		goto out;
74
75	final_tbl = memremap(efi.tpm_final_log,
76			     sizeof(*final_tbl) + final_events_log_size,
77			     MEMREMAP_WB);
78	if (!final_tbl) {
79		pr_err("Could not map UEFI TPM final log\n");
80		devm_kfree(&chip->dev, log->bios_event_log);
81		ret = -ENOMEM;
82		goto out;
83	}
84
85	/*
86	 * The 'final events log' size excludes the 'final events preboot log'
87	 * at its beginning.
88	 */
89	final_events_log_size -= log_tbl->final_events_preboot_size;
90
91	/*
92	 * Allocate memory for the 'combined log' where we will append the
93	 * 'final events log' to.
94	 */
95	tmp = devm_krealloc(&chip->dev, log->bios_event_log,
96			    log_size + final_events_log_size,
97			    GFP_KERNEL);
98	if (!tmp) {
99		devm_kfree(&chip->dev, log->bios_event_log);
100		ret = -ENOMEM;
101		goto out;
102	}
103
104	log->bios_event_log = tmp;
105
106	/*
107	 * Append any of the 'final events log' that didn't also end up in the
108	 * 'main log'. Events can be logged in both if events are generated
109	 * between GetEventLog() and ExitBootServices().
110	 */
111	memcpy((void *)log->bios_event_log + log_size,
112	       final_tbl->events + log_tbl->final_events_preboot_size,
113	       final_events_log_size);
114	/*
115	 * The size of the 'combined log' is the size of the 'main log' plus
116	 * the size of the 'final events log'.
117	 */
118	log->bios_event_log_end = log->bios_event_log +
119		log_size + final_events_log_size;
120
121out:
122	memunmap(final_tbl);
123	memunmap(log_tbl);
124	return ret;
125}
126