[U-Boot] [RFC 1/8] efi_loader: boottime: don't add device path protocol to image handle

AKASHI Takahiro
2019-03-06T00:27:11Z

On Tue, Mar 05, 2019 at 08:48:37PM +0100, Heinrich Schuchardt wrote:
> On 3/5/19 6:53 AM, AKASHI Takahiro wrote:
> > It is just wrong to add devcie path protocol to image handle.
> >
> > Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
> > ---
> > lib/efi_loader/efi_boottime.c | 11 +----------
> > 1 file changed, 1 insertion(+), 10 deletions(-)
> >
> > diff --git a/lib/efi_loader/efi_boottime.c b/lib/efi_loader/efi_boottime.c
> > index bd8b8a17ae71..7bd9c0a952d4 100644
> > --- a/lib/efi_loader/efi_boottime.c
> > +++ b/lib/efi_loader/efi_boottime.c
> > @@ -1540,17 +1540,8 @@ efi_status_t efi_setup_loaded_image(struct efi_device_path *device_path,
> > info->file_path = file_path;
> > info->system_table = &systab;
> >
> > - if (device_path) {
> > + if (device_path)
> > info->device_handle = efi_dp_find_obj(device_path, NULL);
> > - /*
> > - * When asking for the device path interface, return
> > - * bootefi_device_path
> > - */
> > - ret = efi_add_protocol(&obj->header,
> > - &efi_guid_device_path, device_path);
>
> Installing the device path is not the problem. It is the GUID that is
> wrong. Use EFI_LOADED_IMAGE_DEVICE_PATH_PROTOCOL_GUID here.

Okay, but I believe that we need duplicate device_path here
before installing it as EFI_LOADED_IMAGE_DEVICE_PATH_PROTOCOL_GUID.

See this line:

> > info->device_handle = efi_dp_find_obj(device_path, NULL);

Normally, device_path is expected to be already associated with
another handle. We should not allow two handles to share one protocol(data).
That is also why I initially believed that add_protocol() should be removed.

Thanks,
-Takahiro Akashi

> UEFI Spec 2.7:
>
> "The Loaded Image Device Path Protocol must be installed onto the image
> handle of a PE/COFF image loaded through the EFI Boot Service LoadImage()."
>
> Best regards
>
> Heinrich
>
> > - if (ret != EFI_SUCCESS)
> > - goto failure;
> > - }
> >
> > /*
> > * When asking for the loaded_image interface, just
> >
>