Re: [PATCH v6 1/2] tpm: enhance read_log_of() to support Physical TPM event log

[Nayna]

On 11/26/2016 09:45 PM, Jarkko Sakkinen wrote:
> On Sat, Nov 26, 2016 at 07:45:38AM -0500, Nayna Jain wrote:
> > 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@xxxxxxxxxxxxxxxxxx>
> > ---
> >   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..4b0d5e6 100644
> > --- a/drivers/char/tpm/tpm_of.c
> > +++ b/drivers/char/tpm/tpm_of.c
> > @@ -27,6 +27,8 @@ int tpm_read_log_of(struct tpm_chip *chip)
> >   	const u32 *sizep;
> >   	const u64 *basep;
> >   	struct tpm_bios_log *log;
> > +	u32 log_size;
> > +	u64 log_base;
>
> Maybe just base and size?

Hmm.. okay to keep names short, I can change to base/size. And since 
they are used within log function, probably it is implicit that, these 
refer to Log  base address and size.

> >   	log = &chip->log;
> >   	if (chip->dev.parent && chip->dev.parent->of_node)
> > @@ -41,18 +43,35 @@ int tpm_read_log_of(struct tpm_chip *chip)
> >   	if (sizep == NULL || basep == NULL)
> >   		return -EIO;
> >
> > -	if (*sizep == 0) {
> > +	/*
> > +	 * 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.
> > +	 */
> > +	if (of_property_match_string(np, "compatible", "IBM,vtpm") < 0) {
> > +		log_size = be32_to_cpup(sizep);
> > +		log_base = be64_to_cpup(basep);
> > +	} else {
> > +		log_size = *sizep;
> > +		log_base = *basep;
> > +	}
> > +
> > +	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);
> > +	memcpy(chip->log.bios_event_log, __va(log_base), log_size);
>
> Why did you change the first parameter?

Hmm.. yeah..shouldn't be.  Sorry, I think while redoing, I mixed up with 
my previous versions. Will change it.
Thanks for noticing it.

Thanks & Regards,
   - Nayna

> >   	return 0;
> >   }
> > --
> > 2.5.0
>
> /Jarkko