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/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. */ 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 66 /* read binary bios log */ 67 int tpm_read_log_acpi(struct tpm_chip *chip) 68 { 69 struct acpi_tcpa *buff; 70 acpi_status status; 71 void __iomem *virt; 72 u64 len, start; 73 struct tpm_bios_log *log; 74 struct acpi_table_tpm2 *tbl; 75 struct acpi_tpm2_phy *tpm2_phy; 76 int format; 77 int ret; 78 79 log = &chip->log; 80 81 /* Unfortuntely ACPI does not associate the event log with a specific 82 * TPM, like PPI. Thus all ACPI TPMs will read the same log. 83 */ 84 if (!chip->acpi_dev_handle) 85 return -ENODEV; 86 87 if (chip->flags & TPM_CHIP_FLAG_TPM2) { 88 status = acpi_get_table("TPM2", 1, 89 (struct acpi_table_header **)&tbl); 90 if (ACPI_FAILURE(status)) 91 return -ENODEV; 92 93 if (tbl->header.length < 94 sizeof(*tbl) + sizeof(struct acpi_tpm2_phy)) { 95 acpi_put_table((struct acpi_table_header *)tbl); 96 return -ENODEV; 97 } 98 99 tpm2_phy = (void *)tbl + sizeof(*tbl); 100 len = tpm2_phy->log_area_minimum_length; 101 102 start = tpm2_phy->log_area_start_address; 103 if (!start || !len) { 104 acpi_put_table((struct acpi_table_header *)tbl); 105 return -ENODEV; 106 } 107 108 acpi_put_table((struct acpi_table_header *)tbl); 109 format = EFI_TCG2_EVENT_LOG_FORMAT_TCG_2; 110 } else { 111 /* Find TCPA entry in RSDT (ACPI_LOGICAL_ADDRESSING) */ 112 status = acpi_get_table(ACPI_SIG_TCPA, 1, 113 (struct acpi_table_header **)&buff); 114 if (ACPI_FAILURE(status)) 115 return -ENODEV; 116 117 switch (buff->platform_class) { 118 case BIOS_SERVER: 119 len = buff->server.log_max_len; 120 start = buff->server.log_start_addr; 121 break; 122 case BIOS_CLIENT: 123 default: 124 len = buff->client.log_max_len; 125 start = buff->client.log_start_addr; 126 break; 127 } 128 129 acpi_put_table((struct acpi_table_header *)buff); 130 format = EFI_TCG2_EVENT_LOG_FORMAT_TCG_1_2; 131 } 132 133 if (!len) { 134 dev_warn(&chip->dev, "%s: TCPA log area empty\n", __func__); 135 return -EIO; 136 } 137 138 /* malloc EventLog space */ 139 log->bios_event_log = devm_kmalloc(&chip->dev, len, GFP_KERNEL); 140 if (!log->bios_event_log) 141 return -ENOMEM; 142 143 log->bios_event_log_end = log->bios_event_log + len; 144 145 ret = -EIO; 146 virt = acpi_os_map_iomem(start, len); 147 if (!virt) { 148 dev_warn(&chip->dev, "%s: Failed to map ACPI memory\n", __func__); 149 /* try EFI log next */ 150 ret = -ENODEV; 151 goto err; 152 } 153 154 memcpy_fromio(log->bios_event_log, virt, len); 155 156 acpi_os_unmap_iomem(virt, len); 157 158 if (chip->flags & TPM_CHIP_FLAG_TPM2 && 159 !tpm_is_tpm2_log(log->bios_event_log, len)) { 160 /* try EFI log next */ 161 ret = -ENODEV; 162 goto err; 163 } 164 165 return format; 166 167 err: 168 devm_kfree(&chip->dev, log->bios_event_log); 169 log->bios_event_log = NULL; 170 return ret; 171 } 172