[v2,1/5] efi/libstub: Fold efi_tcg2_tagged_event into efi_measured_event

From: Ard Biesheuvel <ardb@kernel.org>

In spite of the efi_ prefix, struct efi_tcg2_tagged_event is specific to
the EFI stub, and so we can tweak it to our liking if needed, e.g., to
accommodate the TDX variant of the TCG2 measurement protocol.

In preparation for that, get rid of it entirely, and combine it with the
efi_measured_event struct used by the measurement code.

Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
 drivers/firmware/efi/libstub/efi-stub-helper.c | 38 +++++++++++---------
 drivers/firmware/efi/libstub/efistub.h         |  7 ----
 2 files changed, 22 insertions(+), 23 deletions(-)

Hi Ard,

On Thu, 7 Mar 2024 at 18:22, Ard Biesheuvel <ardb+git@google.com> wrote:
>
> From: Ard Biesheuvel <ardb@kernel.org>
>
> In spite of the efi_ prefix, struct efi_tcg2_tagged_event is specific to
> the EFI stub, and so we can tweak it to our liking if needed, e.g., to
> accommodate the TDX variant of the TCG2 measurement protocol.
>
> In preparation for that, get rid of it entirely, and combine it with the
> efi_measured_event struct used by the measurement code.
>
> Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
> Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>

> ---
>  drivers/firmware/efi/libstub/efi-stub-helper.c | 38 +++++++++++---------
>  drivers/firmware/efi/libstub/efistub.h         |  7 ----
>  2 files changed, 22 insertions(+), 23 deletions(-)
>
> diff --git a/drivers/firmware/efi/libstub/efi-stub-helper.c b/drivers/firmware/efi/libstub/efi-stub-helper.c
> index bfa30625f5d0..186ced8371ac 100644
> --- a/drivers/firmware/efi/libstub/efi-stub-helper.c
> +++ b/drivers/firmware/efi/libstub/efi-stub-helper.c
> @@ -11,6 +11,7 @@
>
>  #include <linux/efi.h>
>  #include <linux/kernel.h>
> +#include <linux/overflow.h>
>  #include <asm/efi.h>
>  #include <asm/setup.h>
>
> @@ -193,7 +194,7 @@ void efi_apply_loadoptions_quirk(const void **load_options, u32 *load_options_si
>         *load_options_size = load_option_unpacked.optional_data_size;
>  }
>
> -enum efistub_event {
> +enum efistub_event_type {
>         EFISTUB_EVT_INITRD,
>         EFISTUB_EVT_LOAD_OPTIONS,
>         EFISTUB_EVT_COUNT,
> @@ -219,46 +220,51 @@ static const struct {
>         },
>  };
>
> +union efistub_event {
> +       efi_tcg2_event_t        tcg2_data;
> +};
> +
> +struct efistub_measured_event {
> +       union efistub_event     event_data;
> +       u32                     tagged_event_id;
> +       u32                     tagged_event_data_size;
> +       u8                      tagged_event_data[];
> +} __packed;
> +
>  static efi_status_t efi_measure_tagged_event(unsigned long load_addr,
>                                              unsigned long load_size,
> -                                            enum efistub_event event)
> +                                            enum efistub_event_type event)
>  {
> +       struct efistub_measured_event *evt;
> +       int size = struct_size(evt, tagged_event_data,
> +                              events[event].event_data_len);
>         efi_guid_t tcg2_guid = EFI_TCG2_PROTOCOL_GUID;
>         efi_tcg2_protocol_t *tcg2 = NULL;
>         efi_status_t status;
>
>         efi_bs_call(locate_protocol, &tcg2_guid, NULL, (void **)&tcg2);
>         if (tcg2) {
> -               struct efi_measured_event {
> -                       efi_tcg2_event_t        event_data;
> -                       efi_tcg2_tagged_event_t tagged_event;
> -                       u8                      tagged_event_data[];
> -               } *evt;
> -               int size = sizeof(*evt) + events[event].event_data_len;
> -
>                 status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, size,
>                                      (void **)&evt);
>                 if (status != EFI_SUCCESS)
>                         goto fail;
>
> -               evt->event_data = (struct efi_tcg2_event){
> +               evt->event_data.tcg2_data = (struct efi_tcg2_event){
>                         .event_size                     = size,
> -                       .event_header.header_size       = sizeof(evt->event_data.event_header),
> +                       .event_header.header_size       = sizeof(evt->event_data.tcg2_data.event_header),
>                         .event_header.header_version    = EFI_TCG2_EVENT_HEADER_VERSION,
>                         .event_header.pcr_index         = events[event].pcr_index,
>                         .event_header.event_type        = EV_EVENT_TAG,
>                 };
>
> -               evt->tagged_event = (struct efi_tcg2_tagged_event){
> -                       .tagged_event_id                = events[event].event_id,
> -                       .tagged_event_data_size         = events[event].event_data_len,
> -               };
> +               evt->tagged_event_id            = events[event].event_id;
> +               evt->tagged_event_data_size     = events[event].event_data_len;
>
>                 memcpy(evt->tagged_event_data, events[event].event_data,
>                        events[event].event_data_len);
>
>                 status = efi_call_proto(tcg2, hash_log_extend_event, 0,
> -                                       load_addr, load_size, &evt->event_data);
> +                                       load_addr, load_size, &evt->event_data.tcg2_data);
>                 efi_bs_call(free_pool, evt);
>
>                 if (status != EFI_SUCCESS)
> diff --git a/drivers/firmware/efi/libstub/efistub.h b/drivers/firmware/efi/libstub/efistub.h
> index c04b82ea40f2..dae635cc3d4f 100644
> --- a/drivers/firmware/efi/libstub/efistub.h
> +++ b/drivers/firmware/efi/libstub/efistub.h
> @@ -843,14 +843,7 @@ struct efi_tcg2_event {
>         /* u8[] event follows here */
>  } __packed;
>
> -struct efi_tcg2_tagged_event {
> -       u32 tagged_event_id;
> -       u32 tagged_event_data_size;
> -       /* u8  tagged event data follows here */
> -} __packed;
> -
>  typedef struct efi_tcg2_event efi_tcg2_event_t;
> -typedef struct efi_tcg2_tagged_event efi_tcg2_tagged_event_t;
>  typedef union efi_tcg2_protocol efi_tcg2_protocol_t;
>
>  union efi_tcg2_protocol {
> --
> 2.44.0.278.ge034bb2e1d-goog
>