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 static void tpm_bios_log_free(void *data) 67 { 68 kvfree(data); 69 } 70 71 /* read binary bios log */ 72 int tpm_read_log_acpi(struct tpm_chip *chip) 73 { 74 struct acpi_tcpa *buff; 75 acpi_status status; 76 void __iomem *virt; 77 u64 len, start; 78 struct tpm_bios_log *log; 79 struct acpi_table_tpm2 *tbl; 80 struct acpi_tpm2_phy *tpm2_phy; 81 int format; 82 int ret; 83 84 log = &chip->log; 85 86 /* Unfortuntely ACPI does not associate the event log with a specific 87 * TPM, like PPI. Thus all ACPI TPMs will read the same log. 88 */ 89 if (!chip->acpi_dev_handle) 90 return -ENODEV; 91 92 if (chip->flags & TPM_CHIP_FLAG_TPM2) { 93 status = acpi_get_table("TPM2", 1, 94 (struct acpi_table_header **)&tbl); 95 if (ACPI_FAILURE(status)) 96 return -ENODEV; 97 98 if (tbl->header.length < 99 sizeof(*tbl) + sizeof(struct acpi_tpm2_phy)) { 100 acpi_put_table((struct acpi_table_header *)tbl); 101 return -ENODEV; 102 } 103 104 tpm2_phy = (void *)tbl + sizeof(*tbl); 105 len = tpm2_phy->log_area_minimum_length; 106 107 start = tpm2_phy->log_area_start_address; 108 if (!start || !len) { 109 acpi_put_table((struct acpi_table_header *)tbl); 110 return -ENODEV; 111 } 112 113 acpi_put_table((struct acpi_table_header *)tbl); 114 format = EFI_TCG2_EVENT_LOG_FORMAT_TCG_2; 115 } else { 116 /* Find TCPA entry in RSDT (ACPI_LOGICAL_ADDRESSING) */ 117 status = acpi_get_table(ACPI_SIG_TCPA, 1, 118 (struct acpi_table_header **)&buff); 119 if (ACPI_FAILURE(status)) 120 return -ENODEV; 121 122 switch (buff->platform_class) { 123 case BIOS_SERVER: 124 len = buff->server.log_max_len; 125 start = buff->server.log_start_addr; 126 break; 127 case BIOS_CLIENT: 128 default: 129 len = buff->client.log_max_len; 130 start = buff->client.log_start_addr; 131 break; 132 } 133 134 acpi_put_table((struct acpi_table_header *)buff); 135 format = EFI_TCG2_EVENT_LOG_FORMAT_TCG_1_2; 136 } 137 138 if (!len) { 139 dev_warn(&chip->dev, "%s: TCPA log area empty\n", __func__); 140 return -EIO; 141 } 142 143 /* malloc EventLog space */ 144 log->bios_event_log = kvmalloc(len, GFP_KERNEL); 145 if (!log->bios_event_log) 146 return -ENOMEM; 147 148 log->bios_event_log_end = log->bios_event_log + len; 149 150 virt = acpi_os_map_iomem(start, len); 151 if (!virt) { 152 dev_warn(&chip->dev, "%s: Failed to map ACPI memory\n", __func__); 153 /* try EFI log next */ 154 ret = -ENODEV; 155 goto err; 156 } 157 158 memcpy_fromio(log->bios_event_log, virt, len); 159 160 acpi_os_unmap_iomem(virt, len); 161 162 if (chip->flags & TPM_CHIP_FLAG_TPM2 && 163 !tpm_is_tpm2_log(log->bios_event_log, len)) { 164 /* try EFI log next */ 165 ret = -ENODEV; 166 goto err; 167 } 168 169 ret = devm_add_action(&chip->dev, tpm_bios_log_free, log->bios_event_log); 170 if (ret) { 171 log->bios_event_log = NULL; 172 goto err; 173 } 174 175 return format; 176 177 err: 178 tpm_bios_log_free(log->bios_event_log); 179 log->bios_event_log = NULL; 180 return ret; 181 } 182