Hi Heinrich,
On Wed, Nov 04, 2020 at 05:50:16PM +0100, Heinrich Schuchardt wrote:
> On 04.11.20 16:56, Ilias Apalodimas wrote:
> >>>
> >>> u32 tpm2_get_capability(struct udevice *dev, u32 capability, u32
> >>> property,
> >>> - void *buf, size_t prop_count)
> >>> + void *buf, size_t prop_count, bool get_count)
> >>
> >> The implementation would be more stable if we would derive the offset
> >> from field property instead of adding get_count.
> >>
> >
> > We are not defining the tpmv2 internal structures anywhere in U-Boot.
> > That's why the code is doing static sizeof(uX) instead of using offsetof.
> > In the EFI part of the patchset, I've done exaclty that.
> > Working with offsets on well defined struct is better, but out of scope for
> > this
> > patchset imho.
> > We can look into refactoring the generic tpmv2 code once I add the rest of
> > the EFI
> > protocol parts?
>
> Can't we add the structures that we need to tpm-v2.h and use their size
> here?
Yes we can, but the scope of the patch is adding EFI_TCG2_PROTOCOL, not
re-factor the tpmv2
code along the way.
Since the only change on the existing code to support the functionality needed
for the
EFI_TCG2_PROTOCOL protocol is just 4 bytes on an existing buffer, can we stick
to that and
think of refactoring the tpm stuff afterwards?
Regards
/Ilias
>
> Best regards
>
> Heinrich
>
> >
> >>> {
> >>> u8 command_v2[COMMAND_BUFFER_SIZE] = {
> >>
> >> Shouldn't COMMAND_BUFFER_SIZE be changed to something with TPM in the
> >> name, e.g TPM_COMMAND_BUFFER_SIZE?
> >>
> >>> tpm_u16(TPM2_ST_NO_SESSIONS), /* TAG */
> >>> @@ -181,13 +181,17 @@ u32 tpm2_get_capability(struct udevice *dev, u32
> >>> capability, u32 property,
> >>> if (ret)
> >>> return ret;
> >>>
> >>> + /* When reading PCR properties we need the count */
> >>> + properties_off = sizeof(u16) + sizeof(u32) + sizeof(u32) +
> >>> + sizeof(u8) + sizeof(u32);
> >>> /*
> >>> * In the response buffer, the properties are located after the:
> >>> * tag (u16), response size (u32), response code (u32),
> >>> * YES/NO flag (u8), TPM_CAP (u32) and TPMU_CAPABILITIES (u32).
> >>> */
> >>
> >> This comment should be above 'properties_off ='. 'get_count' related
> >> field should be mentioned.
> >
> > Sure, I'll fix this
> >
> > Regards
> > /Ilias
> >>
> >> Best regards
> >>
> >> Heinrich
> >>
> >>> - properties_off = sizeof(u16) + sizeof(u32) + sizeof(u32) +
> >>> - sizeof(u8) + sizeof(u32) + sizeof(u32);
> >>> + if (!get_count)
> >>> + properties_off += sizeof(u32);
> >>> +
> >>> memcpy(buf, &response[properties_off], response_len - properties_off);
> >>>
> >>> return 0;
> >>>
> >>
>
