Re: [PATCH v3 4/5] efi_loader: bootmgr: install the firmware-owned devicetree

[Carlo Caione <ccaione@baylibre.com>]

On Tue, Sep 08, 2026 at 11:37:43 +0100, Ilias Apalodimas wrote:
> Hi Carlo,

Hello Ilias,
 
> On Thu, 3 Sept 2026 at 16:10, Carlo Caione <ccaione@baylibre.com> wrote:
> 
> > SystemReady DeviceTree can boot through the UEFI boot manager without
> > going through the per-device EFI bootmeth. Use firmware_fdt_stage() here
> > as well so both EFI launch paths install the same firmware-owned
> > devicetree.

[...]
> >         if (!IS_ENABLED(CONFIG_GENERATE_ACPI_TABLE)) {
> > +               if (!fdt) {
> > +                       ulong fdt_addr = env_get_hex("fdt_addr_r", 0);
> > +                       int err;
> >
> +
> >
> 
> Any reason we are doing the _hex variant instead of env_get? Don't we want
> to bail out if the env variable isnt defined instead of picking 0x0 ?

We do, but we do that in firmware_fdt_stage() that is returning -EINVAL
before loading or copying the FIT (so we return EFI_DEVICE_ERROR from
this function in the end).

So basically zero is an invalid-address sentinel, never a staging
destination.

> +                       err = firmware_fdt_stage(fdt_addr, &fw_fdt_size,
> > +                                                &fw_fdt_fname);
> > +                       if (!err) {
> > +                               fdt = map_sysmem(fdt_addr, fw_fdt_size);
> > +                       } else if (err != -ENOENT) {
> > +                               log_err("Failed to load firmware
> > devicetree '%s' (err %d)\n",
> > +                                       fw_fdt_fname ? fw_fdt_fname :
> > "fdt.itb", err);
> > +                               ret = EFI_DEVICE_ERROR;
> > +                               goto out;
> > +                       }
> > +               }
> > +
[...]

Ciao,

--
Carlo Caione