Re: [PATCH v2 1/5] efi_loader: bootmgr: preserve a passed devicetree

On Tue, 28 Jul 2026 at 16:20, Carlo Caione <[email protected]> wrote:
>
> An FDT explicitly passed to efi_bootmgr_run() is currently replaced by
> the FDT referenced by the selected Boot#### load option. This makes an
> operator-supplied devicetree ineffective whenever the boot option carries
> one.
>
> Only consult the load-option FDT when no FDT was passed. Document the
> resulting precedence so the explicit call argument remains the
> highest-priority source.
>
> Signed-off-by: Carlo Caione <[email protected]>
> ---

Reviewed-by: Ilias Apalodimas <[email protected]>

>  lib/efi_loader/efi_bootmgr.c | 20 +++++++++++---------
>  1 file changed, 11 insertions(+), 9 deletions(-)
>
> diff --git a/lib/efi_loader/efi_bootmgr.c b/lib/efi_loader/efi_bootmgr.c
> index 8c9a9b5eb56..785484abf23 100644
> --- a/lib/efi_loader/efi_bootmgr.c
> +++ b/lib/efi_loader/efi_bootmgr.c
> @@ -1294,9 +1294,9 @@ out:
>   * efi_bootmgr_run() - execute EFI boot manager
>   * @fdt:       Flat device tree
>   *
> - * Invoke EFI boot manager and execute a binary depending on
> - * boot options. If @fdt is not NULL, it will be passed to
> - * the executed binary.
> + * Invoke the EFI boot manager and execute a binary according to its boot
> + * options. The devicetree precedence, from highest to lowest, is an FDT
> + * passed in @fdt, the Boot#### load-option FDT, then the distro/ESP FDT.
>   *
>   * Return:     status code
>   */
> @@ -1305,7 +1305,7 @@ efi_status_t efi_bootmgr_run(void *fdt)
>         efi_handle_t handle;
>         void *load_options;
>         efi_status_t ret;
> -       void *fdt_lo, *fdt_distro = NULL;
> +       void *fdt_lo = NULL, *fdt_distro = NULL;
>         efi_uintn_t fdt_size;
>
>         /* Initialize EFI drivers */
> @@ -1320,11 +1320,13 @@ efi_status_t efi_bootmgr_run(void *fdt)
>         }
>
>         if (!IS_ENABLED(CONFIG_GENERATE_ACPI_TABLE)) {
> -               ret = load_fdt_from_load_option(&fdt_lo);
> -               if (ret != EFI_SUCCESS)
> -                       return ret;
> -               if (fdt_lo)
> -                       fdt = fdt_lo;
> +               if (!fdt) {
> +                       ret = load_fdt_from_load_option(&fdt_lo);
> +                       if (ret != EFI_SUCCESS)
> +                               return ret;
> +                       if (fdt_lo)
> +                               fdt = fdt_lo;
> +               }
>                 if (!fdt) {
>                         efi_load_distro_fdt(handle, &fdt_distro, &fdt_size);
>                         fdt = fdt_distro;
>
> --
> 2.55.0
>