drivers/char/tpm/tpm_acpi.c

   1 /*
   2  * Copyright (C) 2005 IBM Corporation
   3  *
   4  * Authors:
   5  *      Seiji Munetoh <[email protected]>
   6  *      Stefan Berger <[email protected]>
   7  *      Reiner Sailer <[email protected]>
   8  *      Kylene Hall <[email protected]>
   9  *
  10  * Maintained by: <[email protected]>
  11  *
  12  * Access to the eventlog extended by the TCG BIOS of PC platform
  13  *
  14  * This program is free software; you can redistribute it and/or
  15  * modify it under the terms of the GNU General Public License
  16  * as published by the Free Software Foundation; either version
  17  * 2 of the License, or (at your option) any later version.
  18  *
  19  */
  20
  21 #include <linux/seq_file.h>
  22 #include <linux/fs.h>
  23 #include <linux/security.h>
  24 #include <linux/module.h>
  25 #include <linux/slab.h>
  26 #include <linux/acpi.h>
  27
  28 #include "tpm.h"
  29 #include "tpm_eventlog.h"
  30
  31 struct acpi_tcpa {
  32         struct acpi_table_header hdr;
  33         u16 platform_class;
  34         union {
  35                 struct client_hdr {
  36                         u32 log_max_len __packed;
  37                         u64 log_start_addr __packed;
  38                 } client;
  39                 struct server_hdr {
  40                         u16 reserved;
  41                         u64 log_max_len __packed;
  42                         u64 log_start_addr __packed;
  43                 } server;
  44         };
  45 };
  46
  47 /* read binary bios log */
  48 int read_log(struct tpm_bios_log *log)
  49 {
  50         struct acpi_tcpa *buff;
  51         acpi_status status;
  52         void __iomem *virt;
  53         u64 len, start;
  54
  55         if (log->bios_event_log != NULL) {
  56                 printk(KERN_ERR
  57                        "%s: ERROR - Eventlog already initialized\n",
  58                        __func__);
  59                 return -EFAULT;
  60         }
  61
  62         /* Find TCPA entry in RSDT (ACPI_LOGICAL_ADDRESSING) */
  63         status = acpi_get_table(ACPI_SIG_TCPA, 1,
  64                                 (struct acpi_table_header **)&buff);
  65
  66         if (ACPI_FAILURE(status)) {
  67                 printk(KERN_ERR "%s: ERROR - Could not get TCPA table\n",
  68                        __func__);
  69                 return -EIO;
  70         }
  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                 printk(KERN_ERR "%s: ERROR - 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                 printk("%s: ERROR - Not enough  Memory for BIOS measurements\n",
  92                         __func__);
  93                 return -ENOMEM;
  94         }
  95
  96         log->bios_event_log_end = log->bios_event_log + len;
  97
  98         virt = acpi_os_map_iomem(start, len);
  99         if (!virt) {
 100                 kfree(log->bios_event_log);
 101                 printk("%s: ERROR - Unable to map memory\n", __func__);
 102                 return -EIO;
 103         }
 104
 105         memcpy_fromio(log->bios_event_log, virt, len);
 106
 107         acpi_os_unmap_iomem(virt, len);
 108         return 0;
 109 }