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Date: Wed, 24 Sep 2014 22:02:34 +0300
From: Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
To: Jason Gunthorpe <jgunthorpe@...idianresearch.com>
Cc: tpmdd-devel@...ts.sourceforge.net, Peter Huewe <peterhuewe@....de>,
Marcel Selhorst <tpmdd@...horst.net>,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1 12/12] tpm: TPM2 sysfs attributes
On Wed, Sep 24, 2014 at 11:13:38AM -0600, Jason Gunthorpe wrote:
> On Wed, Sep 24, 2014 at 12:06:02PM +0300, Jarkko Sakkinen wrote:
> > Added tpm2-sysfs.c that implements sysfs attributes for a TPM2
> > device.
>
> You need to document in Documentation every new sysfs that is added.
>
> The existing ones are not documented :(
This came up in Peters reply (you probably saw that).
https://www.kernel.org/doc/Documentation/ABI/stable/sysfs-class-tpm
> > +++ b/drivers/char/tpm/tpm-interface.c
> > @@ -899,6 +899,7 @@ void tpm_remove_hardware(struct device *dev)
> >
> > tpm_chip_unregister(chip);
> >
> > +
> > /* write it this way to be explicit (chip->dev == dev) */
> > put_device(chip->dev);
> > }
>
> Hunk does not belong in this patch
Ack (thanks).
> > diff --git a/drivers/char/tpm/tpm2-commands.c b/drivers/char/tpm/tpm2-commands.c
> > index a21dfd5..6365087 100644
> > +++ b/drivers/char/tpm/tpm2-commands.c
> > @@ -195,7 +195,7 @@ ssize_t tpm2_get_tpm_pt(struct device *dev, u32 property_id, u32* value,
> > cmd.header.in = tpm2_get_tpm_pt_header;
> > cmd.params.tpm2_get_tpm_pt_in.cap_id =
> > cpu_to_be32(TPM2_CAP_TPM_PROPERTIES);
> > - cmd.params.tpm2_get_tpm_pt_in.property_id = property_id;
> > + cmd.params.tpm2_get_tpm_pt_in.property_id = cpu_to_be32(property_id);
> > cmd.params.tpm2_get_tpm_pt_in.property_cnt = cpu_to_be32(1);
>
> Hunk does not belong in this patch
Ack (thanks).
> > +static ssize_t pcrs_show(struct device *dev, struct device_attribute *attr,
> > + char *buf)
> > +{
>
> The pcrs file never conformed to the sysfs rules, if TPM2 is getting a
> whole new file set, I wouldn't mind seeing it not include the
> non-conformant ones. What do you think?
I think that it's better to put extra focus on these sysfs attributes in
first patch set because it's user space visible. What's wrong in the
current pcrs file?
> > +static ssize_t caps_show(struct device *dev, struct device_attribute *attr,
> > + char *buf)
> > +{
>
> Ditto.. The manfacturer number should probably be its own file
Maybe here would make sense to have three files:
- manufacturer
- firmware_1
- firmware_2
More or less following the name of the TPM properties in the
specification.
> > +static ssize_t durations_show(struct device *dev, struct device_attribute *attr,
> > + char *buf)
> > +{
> > + struct tpm_chip *chip = dev_get_drvdata(dev);
> > +
> > + if (chip->vendor.duration[TPM_LONG] == 0)
> > + return 0;
> > +
> > + return sprintf(buf, "%d %d %d [%s]\n",
> > + jiffies_to_usecs(chip->vendor.duration[TPM_SHORT]),
> > + jiffies_to_usecs(chip->vendor.duration[TPM_MEDIUM]),
> > + jiffies_to_usecs(chip->vendor.duration[TPM_LONG]),
> > + chip->vendor.duration_adjusted
> > + ? "adjusted" : "original");
> > +}
> > +static DEVICE_ATTR_RO(durations);
>
> Seem useless since the durations are constant, drop it?
>
> > +static ssize_t timeouts_show(struct device *dev, struct device_attribute *attr,
> > + char *buf)
> > +{
> > + struct tpm_chip *chip = dev_get_drvdata(dev);
> > +
> > + return sprintf(buf, "%d %d %d %d [%s]\n",
> > + jiffies_to_usecs(chip->vendor.timeout_a),
> > + jiffies_to_usecs(chip->vendor.timeout_b),
> > + jiffies_to_usecs(chip->vendor.timeout_c),
> > + jiffies_to_usecs(chip->vendor.timeout_d),
> > + chip->vendor.timeout_adjusted
> > + ? "adjusted" : "original");
> > +}
> > +static DEVICE_ATTR_RO(timeouts);
>
> Ditto
>
> > +static ssize_t version_show(struct device *dev, struct device_attribute *attr,
> > + char *buf)
> > +{
> > + char *str = buf;
> > +
> > + str += sprintf(str, "2.0\n");
> > +
> > + return str - buf;
> > +}
> > +
> > +static DEVICE_ATTR_RO(version);
> > +
> > +
> > +static ssize_t tpm2_show(struct device *dev, struct device_attribute *attr,
> > + char *buf)
> > +{
> > + struct tpm_chip *chip = dev_get_drvdata(dev);
> > +
> > + return sprintf(buf, "%d\n", chip->tpm2);
> > +}
> > +static DEVICE_ATTR_RO(tpm2);
>
> Two things for the same report? Drop one?
>
> Also, I think some thought is needed for the char interface - some
> kind of ioctl to enter TPM2 mode and EINVAL access until that is done?
>
> Finally, this is in the wrong place in sysfs, I suspect it should be
> attached to the char device node, not the platform device node? We
> should at least investigate this...
This was forgotten. Should not be here at all. Instead we have the
variable 'version' to state specification family and level.
I did not fully understand the comment about tpm2 flag. Why driver
cannot set it when it initializes the device like with this based
on value of the STS3?
> > +struct tpm2_permanent {
> > + unsigned int owner_auth_set : 1;
> > + unsigned int endorsement_auth_set : 1;
> > + unsigned int lockout_auth_set : 1;
> > + unsigned int reserved1 : 5;
> > + unsigned int disable_clear : 1;
> > + unsigned int in_lockout : 1;
> > + unsigned int tpm_generated_eps : 1;
> > + unsigned int reserved2 : 21;
> > +};
> > +
> > +struct tpm2_startup_clear {
> > + unsigned int ph_enable : 1;
> > + unsigned int sh_enable : 1;
> > + unsigned int eh_enable : 1;
> > + unsigned int ph_enable_nv : 1;
> > + unsigned int reserved : 27;
> > + unsigned int orderly : 1;
> > +};
>
> This idea is not portable, you cannot use bitfields to index bits in a
> word like this. Please use constants defined with BIT(xx)
Thanks, I'll change this.
> Next posting can you include a github link? Thanks
Yup sure. I do everything for v2 in tpm2-v1 by adding fixes on top of
these patches. When things look good there I'll create a new branch
tpm2-v2 and prepare the next patch set.
> Jason
/Jarkko
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