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

Heinrich Schuchardt
2019-03-06T05:04:55Z

On 3/6/19 1:27 AM, AKASHI Takahiro wrote:
> 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.

The spec says we should use a copy of the unchanged DevicePath parameter
of LoadImage() which may be NULL.

So we have to rework all callers to get the device_path parameter of
efi_setup_loaded_image() right.

Best regards

Heinrich

>
> 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
>>>
>>
>