xref: /openbmc/linux/drivers/firmware/efi/tpm.c (revision bdc11824)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (C) 2017 Google, Inc.
4  *     Thiebaud Weksteen <tweek@google.com>
5  */
6 
7 #define TPM_MEMREMAP(start, size) early_memremap(start, size)
8 #define TPM_MEMUNMAP(start, size) early_memunmap(start, size)
9 
10 #include <asm/early_ioremap.h>
11 #include <linux/efi.h>
12 #include <linux/init.h>
13 #include <linux/memblock.h>
14 #include <linux/tpm_eventlog.h>
15 
16 int efi_tpm_final_log_size;
17 EXPORT_SYMBOL(efi_tpm_final_log_size);
18 
tpm2_calc_event_log_size(void * data,int count,void * size_info)19 static int __init tpm2_calc_event_log_size(void *data, int count, void *size_info)
20 {
21 	struct tcg_pcr_event2_head *header;
22 	int event_size, size = 0;
23 
24 	while (count > 0) {
25 		header = data + size;
26 		event_size = __calc_tpm2_event_size(header, size_info, true);
27 		if (event_size == 0)
28 			return -1;
29 		size += event_size;
30 		count--;
31 	}
32 
33 	return size;
34 }
35 
36 /*
37  * Reserve the memory associated with the TPM Event Log configuration table.
38  */
efi_tpm_eventlog_init(void)39 int __init efi_tpm_eventlog_init(void)
40 {
41 	struct linux_efi_tpm_eventlog *log_tbl;
42 	struct efi_tcg2_final_events_table *final_tbl;
43 	int tbl_size;
44 	int ret = 0;
45 
46 	if (efi.tpm_log == EFI_INVALID_TABLE_ADDR) {
47 		/*
48 		 * We can't calculate the size of the final events without the
49 		 * first entry in the TPM log, so bail here.
50 		 */
51 		return 0;
52 	}
53 
54 	log_tbl = early_memremap(efi.tpm_log, sizeof(*log_tbl));
55 	if (!log_tbl) {
56 		pr_err("Failed to map TPM Event Log table @ 0x%lx\n",
57 		       efi.tpm_log);
58 		efi.tpm_log = EFI_INVALID_TABLE_ADDR;
59 		return -ENOMEM;
60 	}
61 
62 	tbl_size = sizeof(*log_tbl) + log_tbl->size;
63 	memblock_reserve(efi.tpm_log, tbl_size);
64 
65 	if (efi.tpm_final_log == EFI_INVALID_TABLE_ADDR) {
66 		pr_info("TPM Final Events table not present\n");
67 		goto out;
68 	} else if (log_tbl->version != EFI_TCG2_EVENT_LOG_FORMAT_TCG_2) {
69 		pr_warn(FW_BUG "TPM Final Events table invalid\n");
70 		goto out;
71 	}
72 
73 	final_tbl = early_memremap(efi.tpm_final_log, sizeof(*final_tbl));
74 
75 	if (!final_tbl) {
76 		pr_err("Failed to map TPM Final Event Log table @ 0x%lx\n",
77 		       efi.tpm_final_log);
78 		efi.tpm_final_log = EFI_INVALID_TABLE_ADDR;
79 		ret = -ENOMEM;
80 		goto out;
81 	}
82 
83 	tbl_size = 0;
84 	if (final_tbl->nr_events != 0) {
85 		void *events = (void *)efi.tpm_final_log
86 				+ sizeof(final_tbl->version)
87 				+ sizeof(final_tbl->nr_events);
88 
89 		tbl_size = tpm2_calc_event_log_size(events,
90 						    final_tbl->nr_events,
91 						    log_tbl->log);
92 	}
93 
94 	if (tbl_size < 0) {
95 		pr_err(FW_BUG "Failed to parse event in TPM Final Events Log\n");
96 		ret = -EINVAL;
97 		goto out_calc;
98 	}
99 
100 	memblock_reserve(efi.tpm_final_log,
101 			 tbl_size + sizeof(*final_tbl));
102 	efi_tpm_final_log_size = tbl_size;
103 
104 out_calc:
105 	early_memunmap(final_tbl, sizeof(*final_tbl));
106 out:
107 	early_memunmap(log_tbl, sizeof(*log_tbl));
108 	return ret;
109 }
110 
111