drivers/char/tpm/eventlog/acpi.c

   1 /*
   2  * Copyright (C) 2005 IBM Corporation
   3  *
   4  * Authors:
   5  *      Seiji Munetoh <munetoh@jp.ibm.com>
   6  *      Stefan Berger <stefanb@us.ibm.com>
   7  *      Reiner Sailer <sailer@watson.ibm.com>
   8  *      Kylene Hall <kjhall@us.ibm.com>
   9  *      Nayna Jain <nayna@linux.vnet.ibm.com>
  10  *
  11  * Maintained by: <tpmdd-devel@lists.sourceforge.net>
  12  *
  13  * Access to the event log extended by the TCG BIOS of PC platform
  14  *
  15  * This program is free software; you can redistribute it and/or
  16  * modify it under the terms of the GNU General Public License
  17  * as published by the Free Software Foundation; either version
  18  * 2 of the License, or (at your option) any later version.
  19  *
  20  */
  21
  22 #include <linux/seq_file.h>
  23 #include <linux/fs.h>
  24 #include <linux/security.h>
  25 #include <linux/module.h>
  26 #include <linux/slab.h>
  27 #include <linux/acpi.h>
  28 #include <linux/tpm_eventlog.h>
  29
  30 #include "../tpm.h"
  31 #include "common.h"
  32
  33 struct acpi_tcpa {
  34         struct acpi_table_header hdr;
  35         u16 platform_class;
  36         union {
  37                 struct client_hdr {
  38                         u32 log_max_len __packed;
  39                         u64 log_start_addr __packed;
  40                 } client;
  41                 struct server_hdr {
  42                         u16 reserved;
  43                         u64 log_max_len __packed;
  44                         u64 log_start_addr __packed;
  45                 } server;
  46         };
  47 };
  48
  49 /* read binary bios log */
  50 int tpm_read_log_acpi(struct tpm_chip *chip)
  51 {
  52         struct acpi_tcpa *buff;
  53         acpi_status status;
  54         void __iomem *virt;
  55         u64 len, start;
  56         struct tpm_bios_log *log;
  57
  58         if (chip->flags & TPM_CHIP_FLAG_TPM2)
  59                 return -ENODEV;
  60
  61         log = &chip->log;
  62
  63         /* Unfortuntely ACPI does not associate the event log with a specific
  64          * TPM, like PPI. Thus all ACPI TPMs will read the same log.
  65          */
  66         if (!chip->acpi_dev_handle)
  67                 return -ENODEV;
  68
  69         /* Find TCPA entry in RSDT (ACPI_LOGICAL_ADDRESSING) */
  70         status = acpi_get_table(ACPI_SIG_TCPA, 1,
  71                                 (struct acpi_table_header **)&buff);
  72
  73         if (ACPI_FAILURE(status))
  74                 return -ENODEV;
  75
  76         switch(buff->platform_class) {
  77         case BIOS_SERVER:
  78                 len = buff->server.log_max_len;
  79                 start = buff->server.log_start_addr;
  80                 break;
  81         case BIOS_CLIENT:
  82         default:
  83                 len = buff->client.log_max_len;
  84                 start = buff->client.log_start_addr;
  85                 break;
  86         }
  87         if (!len) {
  88                 dev_warn(&chip->dev, "%s: TCPA log area empty\n", __func__);
  89                 return -EIO;
  90         }
  91
  92         /* malloc EventLog space */
  93         log->bios_event_log = kmalloc(len, GFP_KERNEL);
  94         if (!log->bios_event_log)
  95                 return -ENOMEM;
  96
  97         log->bios_event_log_end = log->bios_event_log + len;
  98
  99         virt = acpi_os_map_iomem(start, len);
 100         if (!virt)
 101                 goto err;
 102
 103         memcpy_fromio(log->bios_event_log, virt, len);
 104
 105         acpi_os_unmap_iomem(virt, len);
 106         return EFI_TCG2_EVENT_LOG_FORMAT_TCG_1_2;
 107
 108 err:
 109         kfree(log->bios_event_log);
 110         log->bios_event_log = NULL;
 111         return -EIO;
 112
 113 }