drivers/char/tpm/tpm_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
  29 #include "tpm.h"
  30 #include "tpm_eventlog.h"
  31
  32 struct acpi_tcpa {
  33         struct acpi_table_header hdr;
  34         u16 platform_class;
  35         union {
  36                 struct client_hdr {
  37                         u32 log_max_len __packed;
  38                         u64 log_start_addr __packed;
  39                 } client;
  40                 struct server_hdr {
  41                         u16 reserved;
  42                         u64 log_max_len __packed;
  43                         u64 log_start_addr __packed;
  44                 } server;
  45         };
  46 };
  47
  48 /* read binary bios log */
  49 int tpm_read_log_acpi(struct tpm_chip *chip)
  50 {
  51         struct acpi_tcpa *buff;
  52         acpi_status status;
  53         void __iomem *virt;
  54         u64 len, start;
  55         struct tpm_bios_log *log;
  56
  57         log = &chip->log;
  58
  59         /* Unfortuntely ACPI does not associate the event log with a specific
  60          * TPM, like PPI. Thus all ACPI TPMs will read the same log.
  61          */
  62         if (!chip->acpi_dev_handle)
  63                 return -ENODEV;
  64
  65         /* Find TCPA entry in RSDT (ACPI_LOGICAL_ADDRESSING) */
  66         status = acpi_get_table(ACPI_SIG_TCPA, 1,
  67                                 (struct acpi_table_header **)&buff);
  68
  69         if (ACPI_FAILURE(status))
  70                 return -ENODEV;
  71
  72         switch(buff->platform_class) {
  73         case BIOS_SERVER:
  74                 len = buff->server.log_max_len;
  75                 start = buff->server.log_start_addr;
  76                 break;
  77         case BIOS_CLIENT:
  78         default:
  79                 len = buff->client.log_max_len;
  80                 start = buff->client.log_start_addr;
  81                 break;
  82         }
  83         if (!len) {
  84                 dev_warn(&chip->dev, "%s: TCPA log area empty\n", __func__);
  85                 return -EIO;
  86         }
  87
  88         /* malloc EventLog space */
  89         log->bios_event_log = kmalloc(len, GFP_KERNEL);
  90         if (!log->bios_event_log)
  91                 return -ENOMEM;
  92
  93         log->bios_event_log_end = log->bios_event_log + len;
  94
  95         virt = acpi_os_map_iomem(start, len);
  96         if (!virt)
  97                 goto err;
  98
  99         memcpy_fromio(log->bios_event_log, virt, len);
 100
 101         acpi_os_unmap_iomem(virt, len);
 102         return 0;
 103
 104 err:
 105         kfree(log->bios_event_log);
 106         log->bios_event_log = NULL;
 107         return -EIO;
 108
 109 }