Re: [PATCH] TPM: ACPI/PNP dependency removal

From: Mimi Zohar
Date: Tue May 04 2010 - 18:31:10 EST


On Tue, 2010-05-04 at 15:00 -0700, Randy Dunlap wrote:
> On Tue, 04 May 2010 18:49:20 -0300 Rajiv Andrade wrote:
>
> > This patch pushes the ACPI dependency into the device driver code
> > itself. Now, even without ACPI/PNP enabled, the device can be registered
> > using the TIS specified memory space. This will however result in the
> > lack of access to the bios event log, being the only implication of such
> > ACPI removal.
> >
> > Signed-off-by: Rajiv Andrade <srajiv@xxxxxxxxxxxxxxxxxx>
> > Acked-by: Mimi Zohar <zohar@xxxxxxxxxxxxxxxxxx>
> > ---
> > drivers/char/tpm/Kconfig | 14 +++++++++++---
> > drivers/char/tpm/tpm_tis.c | 42 ++++++++++++++++++++++--------------------
> > 2 files changed, 33 insertions(+), 23 deletions(-)
> >
> > diff --git a/drivers/char/tpm/Kconfig b/drivers/char/tpm/Kconfig
> > index f5fc64f..0a9ec0b 100644
> > --- a/drivers/char/tpm/Kconfig
> > +++ b/drivers/char/tpm/Kconfig
> > @@ -17,20 +17,28 @@ menuconfig TCG_TPM
> > obtained at: <http://sourceforge.net/projects/trousers>. To
> > compile this driver as a module, choose M here; the module
> > will be called tpm. If unsure, say N.
> > - Note: For more TPM drivers enable CONFIG_PNP, CONFIG_ACPI
> > - and CONFIG_PNPACPI.
> > + Note: For more TPM drivers and BIOS LOG access enable
> > + CONFIG_PNP, CONFIG_ACPI and CONFIG_PNPACPI.
> >
> > if TCG_TPM
> >
> > config TCG_TIS
> > tristate "TPM Interface Specification 1.2 Interface"
> > - depends on PNP
> > ---help---
> > If you have a TPM security chip that is compliant with the
> > TCG TIS 1.2 TPM specification say Yes and it will be accessible
> > from within Linux. To compile this driver as a module, choose
> > M here; the module will be called tpm_tis.
> >
> > +config TCG_BIOS_LOG
> > + bool "TPM bios mesurement log"
>
> BIOS measurement
>
> > + depends on X86
> > + select ACPI
> > + ---help---
> > + ACPI is required for access to bios measurements lists and therefore
>
> BIOS
>
> and if I had any say-so, I would Nack this part of the patch.
> Selecting ACPI adds a huge amount of code, so it should just depend on ACPI IMO.

Just posted a patch removing the ACPI dependency from IMA, as IMA can
run with/without ACPI or TPM enabled. However, without ACPI enabled, the
PCR values can not be verified against the BIOS measurement log.

> Also, ACPI depends on PCI and PM, so if this "select" part remains,
> this should be more like:
>
> depends on X86 && PCI && PM
>
> (unless that's already enforced somewhere else).

Thanks.

> > + to validate the PCR[0] value. So say Yes in case you want this
> > + feature and, consequently, ACPI will be enabled.
> > +
> > config TCG_NSC
> > tristate "National Semiconductor TPM Interface"
> > ---help---

Mimi

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