tpm_acpi.c

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/*
 * Copyright (C) 2005 IBM Corporation
 *
 * Authors:
 *  Seiji Munetoh <[email protected]>
 *  Stefan Berger <[email protected]>
 *  Reiner Sailer <[email protected]>
 *  Kylene Hall <[email protected]>
 *
 * Maintained by: <[email protected]>
 *
 * Access to the eventlog extended by the TCG BIOS of PC platform
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 *
 */

#include <linux/seq_file.h>
#include <linux/fs.h>
#include <linux/security.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <acpi/acpi.h>

#include "tpm.h"
#include "tpm_eventlog.h"

struct acpi_tcpa {
    struct acpi_table_header hdr;
    u16 platform_class;
    union {
        struct client_hdr {
            u32 log_max_len __attribute__ ((packed));
            u64 log_start_addr __attribute__ ((packed));
        } client;
        struct server_hdr {
            u16 reserved;
            u64 log_max_len __attribute__ ((packed));
            u64 log_start_addr __attribute__ ((packed));
        } server;
    };
};

/* read binary bios log */
int read_log(struct tpm_bios_log *log)
{
    struct acpi_tcpa *buff;
    acpi_status status;
    void __iomem *virt;
    u64 len, start;

    if (log->bios_event_log != NULL) {
        printk(KERN_ERR
               "%s: ERROR - Eventlog already initialized\n",
               __func__);
        return -EFAULT;
    }

    /* Find TCPA entry in RSDT (ACPI_LOGICAL_ADDRESSING) */
    status = acpi_get_table(ACPI_SIG_TCPA, 1,
                (struct acpi_table_header **)&buff);

    if (ACPI_FAILURE(status)) {
        printk(KERN_ERR "%s: ERROR - Could not get TCPA table\n",
               __func__);
        return -EIO;
    }

    switch(buff->platform_class) {
    case BIOS_SERVER:
        len = buff->server.log_max_len;
        start = buff->server.log_start_addr;
        break;
    case BIOS_CLIENT:
    default:
        len = buff->client.log_max_len;
        start = buff->client.log_start_addr;
        break;
    }
    if (!len) {
        printk(KERN_ERR "%s: ERROR - TCPA log area empty\n", __func__);
        return -EIO;
    }

    /* malloc EventLog space */
    log->bios_event_log = kmalloc(len, GFP_KERNEL);
    if (!log->bios_event_log) {
        printk("%s: ERROR - Not enough  Memory for BIOS measurements\n",
            __func__);
        return -ENOMEM;
    }

    log->bios_event_log_end = log->bios_event_log + len;

    virt = acpi_os_map_memory(start, len);
    if (!virt) {
        kfree(log->bios_event_log);
        printk("%s: ERROR - Unable to map memory\n", __func__);
        return -EIO;
    }

    memcpy_fromio(log->bios_event_log, virt, len);

    acpi_os_unmap_memory(virt, len);
    return 0;
}