linux-kernel - Re: [PATCH] tpm: Add reserved memory event log

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Date:   Tue, 17 Jan 2023 09:09:18 -0600
From:   Eddie James <eajames@...ux.ibm.com>
To:     Jarkko Sakkinen <jarkko@...nel.org>
Cc:     linux-integrity@...r.kernel.org, linux-kernel@...r.kernel.org,
        jgg@...pe.ca, peterhuewe@....de, joel@....id.au
Subject: Re: [PATCH] tpm: Add reserved memory event log


On 1/16/23 00:53, Jarkko Sakkinen wrote:
> On Tue, Jan 03, 2023 at 10:20:10AM -0600, Eddie James wrote:
>> Some platforms may desire to pass the event log up to linux in the
>> form of a reserved memory region. Add support for this in the TPM
>> core to find the reserved memory region and map it.
>>
>> Signed-off-by: Eddie James <eajames@...ux.ibm.com>
> Which platforms?
>
> I do not see information of
>
> +	void (*release)(void *ptr);
>
> in the commit message. The description of the implemenation approach is
> missing.


Hi, please see v2 which is a two patch series. I have changed the 
implementation to avoid this release pointer. 
https://patchwork.kernel.org/project/linux-integrity/list/?series=711832


Thanks,

Eddie


>
>
>> ---
>>   drivers/char/tpm/eventlog/of.c | 38 +++++++++++++++++++++++++++++++++-
>>   drivers/char/tpm/tpm-chip.c    |  3 ++-
>>   include/linux/tpm.h            |  1 +
>>   3 files changed, 40 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/char/tpm/eventlog/of.c b/drivers/char/tpm/eventlog/of.c
>> index a9ce66d09a75..0455d7f61c10 100644
>> --- a/drivers/char/tpm/eventlog/of.c
>> +++ b/drivers/char/tpm/eventlog/of.c
>> @@ -11,12 +11,48 @@
>>    */
>>   
>>   #include <linux/slab.h>
>> +#include <linux/io.h>
>> +#include <linux/ioport.h>
>>   #include <linux/of.h>
>> +#include <linux/of_address.h>
>> +#include <linux/of_reserved_mem.h>
>>   #include <linux/tpm_eventlog.h>
>>   
>>   #include "../tpm.h"
>>   #include "common.h"
>>   
>> +static int tpm_read_log_memory_region(struct tpm_chip *chip)
>> +{
>> +	struct device_node *node;
>> +	struct resource res;
>> +	int rc;
>> +
>> +	node = of_parse_phandle(chip->dev.parent->of_node, "memory-region", 0);
>> +	if (!node) {
>> +		dev_info(&chip->dev, "no phandle\n");
>> +		return -ENODEV;
>> +	}
>> +
>> +	rc = of_address_to_resource(node, 0, &res);
>> +	of_node_put(node);
>> +	if (rc) {
>> +		dev_info(&chip->dev, "no mem\n");
>> +		return rc;
>> +	}
>> +
>> +	chip->log.bios_event_log = memremap(res.start, resource_size(&res), MEMREMAP_WB);
>> +	if (!chip->log.bios_event_log) {
>> +		dev_info(&chip->dev, "err memremap\n");
>> +		return -ENOMEM;
>> +	}
>> +
>> +	chip->log.release = memunmap;
>> +	chip->log.bios_event_log_end = chip->log.bios_event_log + resource_size(&res);
>> +
>> +	return chip->flags & TPM_CHIP_FLAG_TPM2 ? EFI_TCG2_EVENT_LOG_FORMAT_TCG_2 :
>> +		EFI_TCG2_EVENT_LOG_FORMAT_TCG_1_2;
>> +}
> We do not want to support TPM 1.2 for new features.
>
>> +
>>   int tpm_read_log_of(struct tpm_chip *chip)
>>   {
>>   	struct device_node *np;
>> @@ -38,7 +74,7 @@ int tpm_read_log_of(struct tpm_chip *chip)
>>   	sizep = of_get_property(np, "linux,sml-size", NULL);
>>   	basep = of_get_property(np, "linux,sml-base", NULL);
>>   	if (sizep == NULL && basep == NULL)
>> -		return -ENODEV;
>> +		return tpm_read_log_memory_region(chip);
>>   	if (sizep == NULL || basep == NULL)
>>   		return -EIO;
>>   
>> diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
>> index 741d8f3e8fb3..09ea8145d7c6 100644
>> --- a/drivers/char/tpm/tpm-chip.c
>> +++ b/drivers/char/tpm/tpm-chip.c
>> @@ -267,7 +267,7 @@ static void tpm_dev_release(struct device *dev)
>>   	idr_remove(&dev_nums_idr, chip->dev_num);
>>   	mutex_unlock(&idr_lock);
>>   
>> -	kfree(chip->log.bios_event_log);
>> +	chip->log.release(chip->log.bios_event_log);
>>   	kfree(chip->work_space.context_buf);
>>   	kfree(chip->work_space.session_buf);
>>   	kfree(chip->allocated_banks);
>> @@ -324,6 +324,7 @@ struct tpm_chip *tpm_chip_alloc(struct device *pdev,
>>   	init_rwsem(&chip->ops_sem);
>>   
>>   	chip->ops = ops;
>> +	chip->log.release = (void(*)(void *))kfree;
> Why do you need this cast?
>
>>   
>>   	mutex_lock(&idr_lock);
>>   	rc = idr_alloc(&dev_nums_idr, NULL, 0, TPM_NUM_DEVICES, GFP_KERNEL);
>> diff --git a/include/linux/tpm.h b/include/linux/tpm.h
>> index dfeb25a0362d..f1c0b0eb20a5 100644
>> --- a/include/linux/tpm.h
>> +++ b/include/linux/tpm.h
>> @@ -109,6 +109,7 @@ struct tpm_space {
>>   struct tpm_bios_log {
>>   	void *bios_event_log;
>>   	void *bios_event_log_end;
>> +	void (*release)(void *ptr);
>>   };
>>   
>>   struct tpm_chip_seqops {
>> -- 
>> 2.31.1
>>
> BR, Jarkko