[PATCH v2 6/7] tpm: Implement state command for Cr50
Simon Glass
sjg at chromium.org
Mon Aug 22 18:39:00 CEST 2022
Hi Ilias,
On Mon, 22 Aug 2022 at 00:00, Ilias Apalodimas
<ilias.apalodimas at linaro.org> wrote:
>
> Hi Simon,
>
> On Fri, 19 Aug 2022 at 16:47, Simon Glass <sjg at chromium.org> wrote:
> >
> > Hi Ilias,
> >
> > On Thu, 18 Aug 2022 at 01:29, Ilias Apalodimas
> > <ilias.apalodimas at linaro.org> wrote:
> > >
> > > Hi Simon,
> > >
> > > On Wed, 17 Aug 2022 at 21:54, Simon Glass <sjg at chromium.org> wrote:
> > > >
> > > > Hi Ilias,
> > > >
> > > > On Tue, 16 Aug 2022 at 06:43, Ilias Apalodimas
> > > > <ilias.apalodimas at linaro.org> wrote:
> > > > >
> > > > > Hi Simon,
> > > > >
> > > > > I know little of this device and the whole patch seems fine apart from
> > > > > the definitions and declarations of the state functions.
> > > > >
> > > > >
> > > > > On Sat, 13 Aug 2022 at 22:56, Simon Glass <sjg at chromium.org> wrote:
> > > > > >
> > > > >
> > > > > >
> > > > > > drivers/tpm/cr50_i2c.c | 117 +++++++++++++++++++++++++++++++++++++++++
> > > > > > include/tpm-v2.h | 54 +++++++++++++++++++
> > > > > > lib/tpm-v2.c | 24 +++++++++
> > > > >
> > > > > [...]
> > > > >
> > > > > > diff --git a/include/tpm-v2.h b/include/tpm-v2.h
> > > > > > index e79c90b9395..8e90a616220 100644
> > > > > > --- a/include/tpm-v2.h
> > > > > > +++ b/include/tpm-v2.h
> > > > > > @@ -419,6 +419,50 @@ enum {
> > > > > > HR_NV_INDEX = TPM_HT_NV_INDEX << HR_SHIFT,
> > > > > > };
> > > > > >
> > > > > > +/*
> > > > > > + * Operations specific to the Cr50 TPM used on Chromium OS and Android devices
> > > > > > + *
> > > > > > + * FIXME: below is not enough to differentiate between vendors commands
> > > > > > + * of numerous devices. However, the current tpm2 APIs aren't very amenable
> > > > > > + * to extending generically because the marshaling code is assuming all
> > > > > > + * knowledge of all commands.
> > > > > > + */
> > > > > > +#define TPM2_CC_VENDOR_BIT_MASK 0x20000000
> > > > > > +
> > > > > > +#define TPM2_CR50_VENDOR_COMMAND (TPM2_CC_VENDOR_BIT_MASK | 0)
> > > > > > +#define TPM2_CR50_SUB_CMD_IMMEDIATE_RESET 19
> > > > > > +#define TPM2_CR50_SUB_CMD_NVMEM_ENABLE_COMMITS 21
> > > > > > +#define TPM2_CR50_SUB_CMD_REPORT_TPM_STATE 23
> > > > > > +#define TPM2_CR50_SUB_CMD_TURN_UPDATE_ON 24
> > > > > > +#define TPM2_CR50_SUB_CMD_GET_REC_BTN 29
> > > > > > +#define TPM2_CR50_SUB_CMD_TPM_MODE 40
> > > > > > +#define TPM2_CR50_SUB_CMD_GET_BOOT_MODE 52
> > > > > > +#define TPM2_CR50_SUB_CMD_RESET_EC 53
> > > > > > +
> > > > > > +/* Cr50 vendor-specific error codes. */
> > > > > > +#define VENDOR_RC_ERR 0x00000500
> > > > > > +enum cr50_vendor_rc {
> > > > > > + VENDOR_RC_INTERNAL_ERROR = (VENDOR_RC_ERR | 6),
> > > > > > + VENDOR_RC_NO_SUCH_SUBCOMMAND = (VENDOR_RC_ERR | 8),
> > > > > > + VENDOR_RC_NO_SUCH_COMMAND = (VENDOR_RC_ERR | 127),
> > > > > > +};
> > > > > > +
> > > > > > +enum cr50_tpm_mode {
> > > > > > + /*
> > > > > > + * Default state: TPM is enabled, and may be set to either
> > > > > > + * TPM_MODE_ENABLED or TPM_MODE_DISABLED.
> > > > > > + */
> > > > > > + TPM_MODE_ENABLED_TENTATIVE = 0,
> > > > > > +
> > > > > > + /* TPM is enabled, and mode may not be changed. */
> > > > > > + TPM_MODE_ENABLED = 1,
> > > > > > +
> > > > > > + /* TPM is disabled, and mode may not be changed. */
> > > > > > + TPM_MODE_DISABLED = 2,
> > > > > > +
> > > > > > + TPM_MODE_INVALID,
> > > > > > +};
> > > > > > +
> > > > > > /**
> > > > > > * Issue a TPM2_Startup command.
> > > > > > *
> > > > > > @@ -658,4 +702,14 @@ u32 tpm2_disable_platform_hierarchy(struct udevice *dev);
> > > > > > u32 tpm2_submit_command(struct udevice *dev, const u8 *sendbuf,
> > > > > > u8 *recvbuf, size_t *recv_size);
> > > > > >
> > > > > > +/**
> > > > > > + * tpm_cr50_report_state() - Report the Cr50 internal state
> > > > > > + *
> > > > > > + * @dev: TPM device
> > > > > > + * @recvbuf: Buffer to save the response to
> > > > > > + * @recv_size: Pointer to the size of the response buffer
> > > > > > + * Return: result of the operation
> > > > > > + */
> > > > > > +u32 tpm2_cr50_report_state(struct udevice *dev, u8 *recvbuf, size_t *recv_size);
> > > > > > +
> > > > >
> > > > > I think we should keep the generic include files clean for hardware
> > > > > specific details.
> > > > >
> > > > > > #endif /* __TPM_V2_H */
> > > > > > diff --git a/lib/tpm-v2.c b/lib/tpm-v2.c
> > > > > > index 3e240bb4c67..3de4841974a 100644
> > > > > > --- a/lib/tpm-v2.c
> > > > > > +++ b/lib/tpm-v2.c
> > > > > > @@ -679,3 +679,27 @@ u32 tpm2_submit_command(struct udevice *dev, const u8 *sendbuf,
> > > > > > {
> > > > > > return tpm_sendrecv_command(dev, sendbuf, recvbuf, recv_size);
> > > > > > }
> > > > > > +
> > > > > > +u32 tpm2_cr50_report_state(struct udevice *dev, u8 *recvbuf, size_t *recv_size)
> > > > > > +{
> > > > > > + u8 command_v2[COMMAND_BUFFER_SIZE] = {
> > > > > > + /* header 10 bytes */
> > > > > > + tpm_u16(TPM2_ST_NO_SESSIONS), /* TAG */
> > > > > > + tpm_u32(10 + 2), /* Length */
> > > > > > + tpm_u32(TPM2_CR50_VENDOR_COMMAND), /* Command code */
> > > > > > +
> > > > > > + tpm_u16(TPM2_CR50_SUB_CMD_REPORT_TPM_STATE),
> > > > > > + };
> > > > > > + int ret;
> > > > > > +
> > > > > > + ret = tpm_sendrecv_command(dev, command_v2, recvbuf, recv_size);
> > > > > > + log_debug("ret=%s, %x\n", dev->name, ret);
> > > > > > + if (ret)
> > > > > > + return ret;
> > > > > > + if (*recv_size < 12)
> > > > > > + return -ENODATA;
> > > > > > + *recv_size -= 12;
> > > > > > + memcpy(recvbuf, recvbuf + 12, *recv_size);
> > > > > > +
> > > > > > + return 0;
> > > > > > +}
> > > > >
> > > > > Same here, this functions seems ok but shouldn't land in the generic TPM API
> > > >
> > > > So shall I create a new tpm_cr50.h header file? What about the C file?
> > >
> > > Yea the header file seems fine (I assume in drivers/tpm?)
> > >
> > > About the C file, tpm2_cr50_report_state() is called by
> > > cr50_i2c_report_state() which is static in the drivers. Can't we just
> > > move the function there?
> >
> > Just digging into this but I think you have the wrong end of the stick.
> >
> > I have added a new TPM method to the uclass for this. We cannot call
> > functions 'sideways' of that mechanism as it violates how driver model
> > works.
> >
>
> I am not sure I am following here. I saw the uclass patches and they
> seem fine. The only thing that needs to be changed is move the cr50*
> generic functions outside the lib/tpm-v2.c API. This seems doable and
> the only thing that prevents us from doing it is some definitions in
> lib/tpm-utils.h which the new functions need.
>
> I'll go reply on the new patchset.
It would be good to get past this...see my comments on the other patch.
Regards,
Simon
>
> Thanks
> /Ilias
> > The feature is implemented for cr50 and sandbox. It could be
> > implemented for other TPMs if they have any info that can usefully be
> > provided, such as the state of the PCRs or something else useful or
> > important.
> >
> > So I think my patches are already doing all this correctly. Can you
> > please take another look? I'll send v3 as Heinrich had a minor comment
> > on a function comment. Also one of your changes.
> >
> > Regards,
> > Simon
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