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. */ 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 */ 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 acpi_put_table((struct acpi_table_header *)tbl); 95 return -ENODEV; 96 } 97 98 tpm2_phy = (void *)tbl + sizeof(*tbl); 99 len = tpm2_phy->log_area_minimum_length; 100 101 start = tpm2_phy->log_area_start_address; 102 if (!start || !len) { 103 acpi_put_table((struct acpi_table_header *)tbl); 104 return -ENODEV; 105 } 106 107 acpi_put_table((struct acpi_table_header *)tbl); 108 format = EFI_TCG2_EVENT_LOG_FORMAT_TCG_2; 109 } else { 110 /* Find TCPA entry in RSDT (ACPI_LOGICAL_ADDRESSING) */ 111 status = acpi_get_table(ACPI_SIG_TCPA, 1, 112 (struct acpi_table_header **)&buff); 113 if (ACPI_FAILURE(status)) 114 return -ENODEV; 115 116 switch (buff->platform_class) { 117 case BIOS_SERVER: 118 len = buff->server.log_max_len; 119 start = buff->server.log_start_addr; 120 break; 121 case BIOS_CLIENT: 122 default: 123 len = buff->client.log_max_len; 124 start = buff->client.log_start_addr; 125 break; 126 } 127 128 acpi_put_table((struct acpi_table_header *)buff); 129 format = EFI_TCG2_EVENT_LOG_FORMAT_TCG_1_2; 130 } 131 132 if (!len) { 133 dev_warn(&chip->dev, "%s: TCPA log area empty\n", __func__); 134 return -EIO; 135 } 136 137 /* malloc EventLog space */ 138 log->bios_event_log = kmalloc(len, GFP_KERNEL); 139 if (!log->bios_event_log) 140 return -ENOMEM; 141 142 log->bios_event_log_end = log->bios_event_log + len; 143 144 ret = -EIO; 145 virt = acpi_os_map_iomem(start, len); 146 if (!virt) 147 goto err; 148 149 memcpy_fromio(log->bios_event_log, virt, len); 150 151 acpi_os_unmap_iomem(virt, len); 152 153 if (chip->flags & TPM_CHIP_FLAG_TPM2 && 154 !tpm_is_tpm2_log(log->bios_event_log, len)) { 155 /* try EFI log next */ 156 ret = -ENODEV; 157 goto err; 158 } 159 160 return format; 161 162 err: 163 kfree(log->bios_event_log); 164 log->bios_event_log = NULL; 165 return ret; 166 } 167