[PATCH v2 3/3] tpm: allocate tpm event log if missing

[Ilias Apalodimas]

On Tue, 16 Jun 2026 at 11:12, Ludwig Nussel <ludwig.nussel at siemens.com> wrote:
>
> On 6/11/26 11:57, Ilias Apalodimas wrote:
> > On Wed, 10 Jun 2026 at 13:52, Ludwig Nussel <ludwig.nussel at siemens.com> wrote:
> >> [...]
> >>   /**
> >> diff --git a/include/tpm_tcg2.h b/include/tpm_tcg2.h
> >> index eb6afe49e77..db3f6f486e9 100644
> >> --- a/include/tpm_tcg2.h
> >> +++ b/include/tpm_tcg2.h
> >> @@ -162,12 +162,14 @@ struct tcg_efi_spec_id_event {
> >>    * @log_position:      Current entry position
> >>    * @log_size:          Log space available
> >>    * @found:             Boolean indicating if an existing log was discovered
> >> + * @allocated:         Boolean indicating that the log was allocated by u-boot
> >>    */
> >>   struct tcg2_event_log {
> >>          u8 *log;
> >>          u32 log_position;
> >>          u32 log_size;
> >>          bool found;
> >> +       bool allocated;
> >>   };
> >
> > I think it makes more sense to define an eventlog state with a u32 and
> > replace the found boolean with it. e.g
> >
> > #define ELOG_FOUND BIT(0)
> > #define ELOG_ALLOCATED BIT(1) etc
>
> Is there a specific reason why explicit low level bit operations would
> be preferred? Since the structure is only used as internal data
> structure of u-boot, what about declaring bits like this:
>
> +       bool found:1;
> +       bool allocated:1;
>
> Looks like that style is also used within U-Boot.

With the patches I pointed you at there are a bunch of booleans before
this as well, so I doubt declaring bitflelds will make the struct
smaller in the end. Padding/alignment will probably give you the same
size.

OTOH the patches introduce more states that are conceptually relevant
to the eventlog.
The updated struct looks like
struct tcg2_event_log {
void *log;
u32 log_size;
u32 log_position;
void *final_buffer;
u32 final_position;
u32 last_event_size;
bool get_event_called;
bool ebs_called;
bool truncated;
bool found;
bool allocated;
};

The TCG2 code behaves different if GetEvent or ExitBootServices has
been called as far as the EventLog is concerned. So I think it would
make more sense to encode the last four booleans to a 'log_state' (or
something along those lines) variable.

Thanks
/Ilias

>
> cu
> Ludwig
>
> --
> Ludwig Nussel
> Siemens AG
> www.siemens.com