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torvalds
GitHub Repository: torvalds/linux
 Path: blob/master/drivers/char/tpm/eventlog/of.c
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// SPDX-License-Identifier: GPL-2.0-or-later

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/*

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 * Copyright 2012 IBM Corporation

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 *

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 * Author: Ashley Lai <[email protected]>

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 *         Nayna Jain <[email protected]>

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 *

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 * Maintained by: <[email protected]>

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 *

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 * Read the event log created by the firmware on PPC64

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 */

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#include <linux/device.h>

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#include <linux/slab.h>

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#include <linux/io.h>

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#include <linux/ioport.h>

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#include <linux/of.h>

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#include <linux/of_address.h>

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#include <linux/of_reserved_mem.h>

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#include <linux/tpm_eventlog.h>

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#include "../tpm.h"

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#include "common.h"

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static int tpm_read_log_memory_region(struct tpm_chip *chip)

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{

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	struct resource res;

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	int rc;

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	rc = of_reserved_mem_region_to_resource(chip->dev.parent->of_node, 0, &res);

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	if (rc)

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		return rc;

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	chip->log.bios_event_log = devm_memremap(&chip->dev, res.start, resource_size(&res),

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						 MEMREMAP_WB);

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	if (IS_ERR(chip->log.bios_event_log))

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		return -ENOMEM;

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	chip->log.bios_event_log_end = chip->log.bios_event_log + resource_size(&res);

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	return chip->flags & TPM_CHIP_FLAG_TPM2 ? EFI_TCG2_EVENT_LOG_FORMAT_TCG_2 :

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		EFI_TCG2_EVENT_LOG_FORMAT_TCG_1_2;

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}

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int tpm_read_log_of(struct tpm_chip *chip)

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{

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	struct device_node *np;

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	const u32 *sizep;

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	const u64 *basep;

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	struct tpm_bios_log *log;

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	u32 size;

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	u64 base;

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	log = &chip->log;

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	if (chip->dev.parent && chip->dev.parent->of_node)

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		np = chip->dev.parent->of_node;

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	else

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		return -ENODEV;

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	if (of_property_read_bool(np, "powered-while-suspended"))

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		chip->flags |= TPM_CHIP_FLAG_ALWAYS_POWERED;

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	sizep = of_get_property(np, "linux,sml-size", NULL);

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	basep = of_get_property(np, "linux,sml-base", NULL);

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	if (sizep == NULL && basep == NULL)

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		return tpm_read_log_memory_region(chip);

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	if (sizep == NULL || basep == NULL)

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		return -EIO;

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	/*

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	 * For both vtpm/tpm, firmware has log addr and log size in big

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	 * endian format. But in case of vtpm, there is a method called

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	 * sml-handover which is run during kernel init even before

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	 * device tree is setup. This sml-handover function takes care

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	 * of endianness and writes to sml-base and sml-size in little

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	 * endian format. For this reason, vtpm doesn't need conversion

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	 * but physical tpm needs the conversion.

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	 */

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	if (of_property_match_string(np, "compatible", "IBM,vtpm") < 0 &&

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	    of_property_match_string(np, "compatible", "IBM,vtpm20") < 0) {

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		size = be32_to_cpup((__force __be32 *)sizep);

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		base = be64_to_cpup((__force __be64 *)basep);

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	} else {

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		size = *sizep;

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		base = *basep;

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	}

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	if (size == 0) {

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		dev_warn(&chip->dev, "%s: Event log area empty\n", __func__);

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		return -EIO;

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	}

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	log->bios_event_log = devm_kmemdup(&chip->dev, __va(base), size, GFP_KERNEL);

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	if (!log->bios_event_log)

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		return -ENOMEM;

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

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	if (chip->flags & TPM_CHIP_FLAG_TPM2)

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		return EFI_TCG2_EVENT_LOG_FORMAT_TCG_2;

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	return EFI_TCG2_EVENT_LOG_FORMAT_TCG_1_2;

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}

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