[U-Boot] [PATCH v2 4/8] x86: Tidy up selection of building the EFI stub

[Bin Meng]

Hi Simon,

On Wed, Sep 28, 2016 at 10:43 PM, Simon Glass <sjg at chromium.org> wrote:
> Hi Bin,
>
> On 27 September 2016 at 19:23, Bin Meng <bmeng.cn at gmail.com> wrote:
>> Hi Simon,
>>
>> On Wed, Sep 28, 2016 at 1:55 AM, Simon Glass <sjg at chromium.org> wrote:
>>> Hi Bin,
>>>
>>> On 26 September 2016 at 20:44, Bin Meng <bmeng.cn at gmail.com> wrote:
>>>> Hi Simon,
>>>>
>>>> On Tue, Sep 27, 2016 at 8:35 AM, Simon Glass <sjg at chromium.org> wrote:
>>>>> Hi Bin,
>>>>>
>>>>> On 26 September 2016 at 02:50, Bin Meng <bmeng.cn at gmail.com> wrote:
>>>>>> Hi Simon,
>>>>>>
>>>>>> On Mon, Sep 26, 2016 at 5:27 AM, Simon Glass <sjg at chromium.org> wrote:
>>>>>>> At present we use a CONFIG option in efi.h to determine whether we are
>>>>>>> building the EFI stub or not. This means that the same header cannot be
>>>>>>> used for EFI_LOADER support. The CONFIG option will be enabled for the
>>>>>>> whole build, even when not building the stub.
>>>>>>>
>>>>>>> Use a different define instead, set up just for the files that make up the
>>>>>>> stub.
>>>>>>>
>>>>>>> Signed-off-by: Simon Glass <sjg at chromium.org>
>>>>>>> ---
>>>>>>>
>>>>>>> Changes in v2:
>>>>>>> - Add new patch to tidy up selection of building the EFI stub
>>>>>>>
>>>>>>>  include/efi.h    | 7 +++++--
>>>>>>>  lib/efi/Makefile | 4 ++--
>>>>>>>  2 files changed, 7 insertions(+), 4 deletions(-)
>>>>>>>
>>>>>>> diff --git a/include/efi.h b/include/efi.h
>>>>>>> index d07187c..3d58780 100644
>>>>>>> --- a/include/efi.h
>>>>>>> +++ b/include/efi.h
>>>>>>> @@ -30,8 +30,11 @@ struct efi_device_path;
>>>>>>>
>>>>>>>  #define EFI_BITS_PER_LONG      BITS_PER_LONG
>>>>>>>
>>>>>>> -/* With 64-bit EFI stub, EFI_BITS_PER_LONG has to be 64 */
>>>>>>> -#ifdef CONFIG_EFI_STUB_64BIT
>>>>>>> +/*
>>>>>>> + * With 64-bit EFI stub, EFI_BITS_PER_LONG has to be 64. EFI_STUB is set
>>>>>>> + * in lib/efi/Makefile, when building the stub.
>>>>>>> + */
>>>>>>> +#if defined(CONFIG_EFI_STUB_64BIT) && defined(EFI_STUB)
>>>>>>
>>>>>> I don't understand why this is needed?
>>>>>
>>>>> If building the 64-bit EFI stub, we need to use 64-bit ints for the
>>>>> stub, but 32-bits for the rest of U-Boot. So this header gets used
>>>>> both ways.
>>>>>
>>>>
>>>> For 32-bit EFI stub or U-Boot itself, EFI_BITS_PER_LONG is defined as
>>>> BITS_PER_LONG which is 32.
>>>
>>> Yes that's right. But in the case of the stub, it can be different
>>> from U-Boot itself. This case takes care of that.
>>>
>>
>> Sorry but I still don't get it. What's broken without this change?
>
> When building U-Boot with CONFIG_EFI_STUB_64BIT enabled, at present
> EFI_BITS_PER_LONG will be 64.
>
> This is fine for building the stub.
>

Yes

> But for building U-Boot, we still want it to be 32.
>

Yes

> At present the code overrides EFI_BITS_PER_LONG, setting it to 64 if
> CONFIG_EFI_STUB_64BIT is enabled.
>
> This means that EFI_LOADER support does not build properly, since it
> uses 64 instead of 32.
>

So you want CONFIG_EFI_STUB_64BIT and CONFIG_EFI_LOADER both be
defined? I don't think it is a valid configuration.

> You can try building without this commit to see the result.
>

Regards,
Bin