LXR linux/drivers/char/tpm/eventlog/acpi.c

   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
  28struct 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/* read binary bios log */
  45int tpm_read_log_acpi(struct tpm_chip *chip)
  46{
  47        struct acpi_tcpa *buff;
  48        acpi_status status;
  49        void __iomem *virt;
  50        u64 len, start;
  51        struct tpm_bios_log *log;
  52        struct acpi_table_tpm2 *tbl;
  53        struct acpi_tpm2_phy *tpm2_phy;
  54        int format;
  55
  56        log = &chip->log;
  57
  58        /* Unfortuntely ACPI does not associate the event log with a specific
  59         * TPM, like PPI. Thus all ACPI TPMs will read the same log.
  60         */
  61        if (!chip->acpi_dev_handle)
  62                return -ENODEV;
  63
  64        if (chip->flags & TPM_CHIP_FLAG_TPM2) {
  65                status = acpi_get_table("TPM2", 1,
  66                                        (struct acpi_table_header **)&tbl);
  67                if (ACPI_FAILURE(status))
  68                        return -ENODEV;
  69
  70                if (tbl->header.length <
  71                                sizeof(*tbl) + sizeof(struct acpi_tpm2_phy))
  72                        return -ENODEV;
  73
  74                tpm2_phy = (void *)tbl + sizeof(*tbl);
  75                len = tpm2_phy->log_area_minimum_length;
  76
  77                start = tpm2_phy->log_area_start_address;
  78                if (!start || !len)
  79                        return -ENODEV;
  80
  81                format = EFI_TCG2_EVENT_LOG_FORMAT_TCG_2;
  82        } else {
  83                /* Find TCPA entry in RSDT (ACPI_LOGICAL_ADDRESSING) */
  84                status = acpi_get_table(ACPI_SIG_TCPA, 1,
  85                                        (struct acpi_table_header **)&buff);
  86                if (ACPI_FAILURE(status))
  87                        return -ENODEV;
  88
  89                switch (buff->platform_class) {
  90                case BIOS_SERVER:
  91                        len = buff->server.log_max_len;
  92                        start = buff->server.log_start_addr;
  93                        break;
  94                case BIOS_CLIENT:
  95                default:
  96                        len = buff->client.log_max_len;
  97                        start = buff->client.log_start_addr;
  98                        break;
  99                }
 100
 101                format = EFI_TCG2_EVENT_LOG_FORMAT_TCG_1_2;
 102        }
 103        if (!len) {
 104                dev_warn(&chip->dev, "%s: TCPA log area empty\n", __func__);
 105                return -EIO;
 106        }
 107
 108        /* malloc EventLog space */
 109        log->bios_event_log = kmalloc(len, GFP_KERNEL);
 110        if (!log->bios_event_log)
 111                return -ENOMEM;
 112
 113        log->bios_event_log_end = log->bios_event_log + len;
 114
 115        virt = acpi_os_map_iomem(start, len);
 116        if (!virt)
 117                goto err;
 118
 119        memcpy_fromio(log->bios_event_log, virt, len);
 120
 121        acpi_os_unmap_iomem(virt, len);
 122        return format;
 123
 124err:
 125        kfree(log->bios_event_log);
 126        log->bios_event_log = NULL;
 127        return -EIO;
 128
 129}
 130