drivers/char/tpm/eventlog/efi.c

   1 /*
   2  * Copyright (C) 2017 Google
   3  *
   4  * Authors:
   5  *      Thiebaud Weksteen <tweek@google.com>
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License
   9  * as published by the Free Software Foundation; either version
  10  * 2 of the License, or (at your option) any later version.
  11  *
  12  */
  13
  14 #include <linux/efi.h>
  15 #include <linux/tpm_eventlog.h>
  16
  17 #include "../tpm.h"
  18 #include "common.h"
  19
  20 /* read binary bios log from EFI configuration table */
  21 int tpm_read_log_efi(struct tpm_chip *chip)
  22 {
  23
  24         struct linux_efi_tpm_eventlog *log_tbl;
  25         struct tpm_bios_log *log;
  26         u32 log_size;
  27         u8 tpm_log_version;
  28
  29         if (!(chip->flags & TPM_CHIP_FLAG_TPM2))
  30                 return -ENODEV;
  31
  32         if (efi.tpm_log == EFI_INVALID_TABLE_ADDR)
  33                 return -ENODEV;
  34
  35         log = &chip->log;
  36
  37         log_tbl = memremap(efi.tpm_log, sizeof(*log_tbl), MEMREMAP_WB);
  38         if (!log_tbl) {
  39                 pr_err("Could not map UEFI TPM log table !\n");
  40                 return -ENOMEM;
  41         }
  42
  43         log_size = log_tbl->size;
  44         memunmap(log_tbl);
  45
  46         log_tbl = memremap(efi.tpm_log, sizeof(*log_tbl) + log_size,
  47                            MEMREMAP_WB);
  48         if (!log_tbl) {
  49                 pr_err("Could not map UEFI TPM log table payload!\n");
  50                 return -ENOMEM;
  51         }
  52
  53         /* malloc EventLog space */
  54         log->bios_event_log = kmemdup(log_tbl->log, log_size, GFP_KERNEL);
  55         if (!log->bios_event_log)
  56                 goto err_memunmap;
  57         log->bios_event_log_end = log->bios_event_log + log_size;
  58
  59         tpm_log_version = log_tbl->version;
  60         memunmap(log_tbl);
  61         return tpm_log_version;
  62
  63 err_memunmap:
  64         memunmap(log_tbl);
  65         return -ENOMEM;
  66 }