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[PATCH v5 2/3] tpm: enhance read_log_of() to support Physical TPM event log

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  [PATCH v5 2/3] tpm: enhance read_log_of() to support Physical TPM event log Nayna Jain <nayna@linux.vnet.ibm.com> - 2016-11-23 18:30 +0100
    Re: [PATCH v5 2/3] tpm: enhance read_log_of() to support Physical  TPM event log Jason Gunthorpe <jgunthorpe@obsidianresearch.com> - 2016-11-23 20:40 +0100
      Re: [PATCH v5 2/3] tpm: enhance read_log_of() to support Physical TPM  event log Nayna <nayna@linux.vnet.ibm.com> - 2016-11-24 09:00 +0100
    Re: [PATCH v5 2/3] tpm: enhance read_log_of() to support Physical  TPM event log Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> - 2016-11-24 22:10 +0100

#1528619 — [PATCH v5 2/3] tpm: enhance read_log_of() to support Physical TPM event log

Physical TPMs use Open Firmware Device Tree bindings that are similar
to the IBM Power virtual TPM to support event log. However, these
properties store the values in different endianness for Physical
and Virtual TPM.

This patch fixes the endianness issue by doing appropriate conversion
based on Physical or Virtual TPM.

Signed-off-by: Nayna Jain <nayna@linux.vnet.ibm.com>
---
 drivers/char/tpm/tpm_of.c | 27 +++++++++++++++++++++++----
 1 file changed, 23 insertions(+), 4 deletions(-)

diff --git a/drivers/char/tpm/tpm_of.c b/drivers/char/tpm/tpm_of.c
index 7dee42d7..646aec1 100644
--- a/drivers/char/tpm/tpm_of.c
+++ b/drivers/char/tpm/tpm_of.c
@@ -27,6 +27,7 @@ int tpm_read_log_of(struct tpm_chip *chip)
 	const u32 *sizep;
 	const u64 *basep;
 	struct tpm_bios_log *log;
+	u32 log_size;
 
 	log = &chip->log;
 	if (chip->dev.parent && chip->dev.parent->of_node)
@@ -34,25 +35,43 @@ int tpm_read_log_of(struct tpm_chip *chip)
 	else
 		return -ENODEV;
 
+	/*
+	 * For both vtpm/tpm, firmware has log addr and log size in big
+	 * endian format. But in case of vtpm, there is a method called
+	 * sml-handover which is run during kernel init even before
+	 * device tree is setup. This sml-handover function takes care
+	 * of endianness and writes to sml-base and sml-size in little
+	 * endian format. For this reason, vtpm doesn't need conversion
+	 * but physical tpm needs the conversion.
+	 */
 	sizep = of_get_property(np, "linux,sml-size", NULL);
+	if (of_property_match_string(np, "compatible", "IBM,vtpm") < 0)
+		log_size = be32_to_cpup(sizep);
+	else
+		log_size = *sizep;
+
 	basep = of_get_property(np, "linux,sml-base", NULL);
 	if (sizep == NULL && basep == NULL)
 		return -ENODEV;
 	if (sizep == NULL || basep == NULL)
 		return -EIO;
 
-	if (*sizep == 0) {
+	if (log_size == 0) {
 		dev_warn(&chip->dev, "%s: Event log area empty\n", __func__);
 		return -EIO;
 	}
 
-	log->bios_event_log = kmalloc(*sizep, GFP_KERNEL);
+	log->bios_event_log = kmalloc(log_size, GFP_KERNEL);
 	if (!log->bios_event_log)
 		return -ENOMEM;
 
-	log->bios_event_log_end = log->bios_event_log + *sizep;
+	log->bios_event_log_end = log->bios_event_log + log_size;
 
-	memcpy(log->bios_event_log, __va(*basep), *sizep);
+	if (of_property_match_string(np, "compatible", "IBM,vtpm") < 0)
+		memcpy(chip->log.bios_event_log, __va(be64_to_cpup(basep)),
+		       log_size);
+	else
+		memcpy(chip->log.bios_event_log, __va(*basep), log_size);
 
 	return 0;
 }
-- 
2.5.0

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#1528711 — Re: [PATCH v5 2/3] tpm: enhance read_log_of() to support Physical TPM event log

On Wed, Nov 23, 2016 at 12:27:36PM -0500, Nayna Jain wrote:
>  	sizep = of_get_property(np, "linux,sml-size", NULL);
> +	if (of_property_match_string(np, "compatible", "IBM,vtpm") < 0)
> +		log_size = be32_to_cpup(sizep);
> +	else
> +		log_size = *sizep;
> +

Uh, no, sizep can be null at this point:

>  	basep = of_get_property(np, "linux,sml-base", NULL);
>  	if (sizep == NULL && basep == NULL)
>  		return -ENODEV;
>  	if (sizep == NULL || basep == NULL)
>  		return -EIO;

Move the if here.

> -	if (*sizep == 0) {
> +	if (log_size == 0) {
>  		dev_warn(&chip->dev, "%s: Event log area empty\n", __func__);
>  		return -EIO;
>  	}
>  
> -	log->bios_event_log = kmalloc(*sizep, GFP_KERNEL);
> +	log->bios_event_log = kmalloc(log_size, GFP_KERNEL);
>  	if (!log->bios_event_log)
>  		return -ENOMEM;
>  
> -	log->bios_event_log_end = log->bios_event_log + *sizep;
> +	log->bios_event_log_end = log->bios_event_log + log_size;
>  
> -	memcpy(log->bios_event_log, __va(*basep), *sizep);
> +	if (of_property_match_string(np, "compatible", "IBM,vtpm") < 0)
> +		memcpy(chip->log.bios_event_log, __va(be64_to_cpup(basep)),
> +		       log_size);
> +	else
> +		memcpy(chip->log.bios_event_log, __va(*basep),
> log_size);

And move the conditional swap of basep up to be along side sizep as
well (ie get rid of the second of_property_match_string)

Jason

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#1529046 — Re: [PATCH v5 2/3] tpm: enhance read_log_of() to support Physical TPM event log

On 11/24/2016 01:07 AM, Jason Gunthorpe wrote:
> On Wed, Nov 23, 2016 at 12:27:36PM -0500, Nayna Jain wrote:
>>   	sizep = of_get_property(np, "linux,sml-size", NULL);
>> +	if (of_property_match_string(np, "compatible", "IBM,vtpm") < 0)
>> +		log_size = be32_to_cpup(sizep);
>> +	else
>> +		log_size = *sizep;
>> +
>
> Uh, no, sizep can be null at this point:

Oops !! Missed the basic. Will fix it. Sorry, and Thanks for noticing.

>
>>   	basep = of_get_property(np, "linux,sml-base", NULL);
>>   	if (sizep == NULL && basep == NULL)
>>   		return -ENODEV;
>>   	if (sizep == NULL || basep == NULL)
>>   		return -EIO;
>
> Move the if here.

Yeah..

>
>> -	if (*sizep == 0) {
>> +	if (log_size == 0) {
>>   		dev_warn(&chip->dev, "%s: Event log area empty\n", __func__);
>>   		return -EIO;
>>   	}
>>
>> -	log->bios_event_log = kmalloc(*sizep, GFP_KERNEL);
>> +	log->bios_event_log = kmalloc(log_size, GFP_KERNEL);
>>   	if (!log->bios_event_log)
>>   		return -ENOMEM;
>>
>> -	log->bios_event_log_end = log->bios_event_log + *sizep;
>> +	log->bios_event_log_end = log->bios_event_log + log_size;
>>
>> -	memcpy(log->bios_event_log, __va(*basep), *sizep);
>> +	if (of_property_match_string(np, "compatible", "IBM,vtpm") < 0)
>> +		memcpy(chip->log.bios_event_log, __va(be64_to_cpup(basep)),
>> +		       log_size);
>> +	else
>> +		memcpy(chip->log.bios_event_log, __va(*basep),
>> log_size);
>
> And move the conditional swap of basep up to be along side sizep as
> well (ie get rid of the second of_property_match_string)
>

Yeah.. true.. Will fix this also.

Thanks & Regards,
    - Nayna

> Jason
>

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#1529702 — Re: [PATCH v5 2/3] tpm: enhance read_log_of() to support Physical TPM event log

On Wed, Nov 23, 2016 at 12:27:36PM -0500, Nayna Jain wrote:
> -	memcpy(log->bios_event_log, __va(*basep), *sizep);
> +	if (of_property_match_string(np, "compatible", "IBM,vtpm") < 0)
> +		memcpy(chip->log.bios_event_log, __va(be64_to_cpup(basep)),
> +		       log_size);
> +	else
> +		memcpy(chip->log.bios_event_log, __va(*basep), log_size);


This does not look good. You should be able rearrange your code in a way
that you only have only one memcpy call.

/Jarkko

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