tpm_acpi.c 2.5 KB
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/*
 * Copyright (C) 2005 IBM Corporation
 *
 * Authors:
 *	Seiji Munetoh <munetoh@jp.ibm.com>
 *	Stefan Berger <stefanb@us.ibm.com>
 *	Reiner Sailer <sailer@watson.ibm.com>
 *	Kylene Hall <kjhall@us.ibm.com>
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 *	Nayna Jain <nayna@linux.vnet.ibm.com>
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 *
 * Maintained by: <tpmdd-devel@lists.sourceforge.net>
 *
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 * Access to the event log extended by the TCG BIOS of PC platform
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 *
 * 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>
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#include <linux/acpi.h>
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#include "tpm.h"
#include "tpm_eventlog.h"

struct acpi_tcpa {
	struct acpi_table_header hdr;
	u16 platform_class;
	union {
		struct client_hdr {
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			u32 log_max_len __packed;
			u64 log_start_addr __packed;
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		} client;
		struct server_hdr {
			u16 reserved;
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			u64 log_max_len __packed;
			u64 log_start_addr __packed;
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		} server;
	};
};

/* read binary bios log */
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int tpm_read_log_acpi(struct tpm_chip *chip)
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{
	struct acpi_tcpa *buff;
	acpi_status status;
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	void __iomem *virt;
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	u64 len, start;
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	struct tpm_bios_log *log;
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	if (chip->flags & TPM_CHIP_FLAG_TPM2)
		return -ENODEV;

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	log = &chip->log;
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	/* Unfortuntely ACPI does not associate the event log with a specific
	 * TPM, like PPI. Thus all ACPI TPMs will read the same log.
	 */
	if (!chip->acpi_dev_handle)
		return -ENODEV;

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

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	if (ACPI_FAILURE(status))
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		return -ENODEV;
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	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) {
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		dev_warn(&chip->dev, "%s: TCPA log area empty\n", __func__);
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		return -EIO;
	}

	/* malloc EventLog space */
	log->bios_event_log = kmalloc(len, GFP_KERNEL);
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	if (!log->bios_event_log)
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		return -ENOMEM;

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

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	virt = acpi_os_map_iomem(start, len);
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	if (!virt)
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		goto err;
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	memcpy_fromio(log->bios_event_log, virt, len);
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	acpi_os_unmap_iomem(virt, len);
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	return 0;
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err:
	kfree(log->bios_event_log);
	log->bios_event_log = NULL;
	return -EIO;

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}