[PATCH v2 6/8] efi_loader: return binary from efi_dp_from_lo()

[Ilias Apalodimas]

On Tue, 28 May 2024 at 17:43, Heinrich Schuchardt
<heinrich.schuchardt at canonical.com> wrote:
>
> For finding distro supplied device-trees we need to know from which device
> we are booting. This can be identified via the device-path of the binary.
>
> Up to now efi_dp_from_lo() only could return the initrd or fdt device-path.
> Allow returning the binary device-path, too.
>
> Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt at canonical.com>
> ---
> v2:
>         no change
> ---
>  lib/efi_loader/efi_device_path.c | 20 ++++++++++++--------
>  1 file changed, 12 insertions(+), 8 deletions(-)
>
> diff --git a/lib/efi_loader/efi_device_path.c b/lib/efi_loader/efi_device_path.c
> index c8c8d54f733..52e3313c23a 100644
> --- a/lib/efi_loader/efi_device_path.c
> +++ b/lib/efi_loader/efi_device_path.c
> @@ -1133,17 +1133,18 @@ ssize_t efi_dp_check_length(const struct efi_device_path *dp,
>  }
>
>  /**
> - * efi_dp_from_lo() - Get the instance of a VenMedia node in a
> - *                    multi-instance device path that matches
> - *                    a specific GUID. This kind of device paths
> - *                    is found in Boot#### options describing an
> - *                    initrd location
> + * efi_dp_from_lo() - get device-path from load option
>   *
> - * @lo:                EFI_LOAD_OPTION containing a valid device path
> - * @guid:      guid to search for
> + * The load options in U-Boot may contain multiple concatenated device-paths.
> + * The first device-path indicates the EFI binary to execute. Subsequent
> + * device-paths start with a VenMedia node where the GUID identifies the
> + * function (initrd or fdt).
> + *
> + * @lo:                EFI load option containing a valid device path
> + * @guid:      GUID identifying device-path or NULL for the EFI binary
>   *
>   * Return:
> - * device path including the VenMedia node or NULL.
> + * device path excluding the matched VenMedia node or NULL.

thanks for catching the typo as well

>   * Caller must free the returned value.
>   */
>  struct
> @@ -1154,6 +1155,9 @@ efi_device_path *efi_dp_from_lo(struct efi_load_option *lo,
>         struct efi_device_path_vendor *vendor;
>         int lo_len = lo->file_path_length;
>
> +       if (!guid)
> +               return efi_dp_dup(fp);
> +
>         for (; lo_len >=  sizeof(struct efi_device_path);
>              lo_len -= fp->length, fp = (void *)fp + fp->length) {
>                 if (lo_len < 0 || efi_dp_check_length(fp, lo_len) < 0)
> --
> 2.43.0
>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas at linaro.org>