[edk2] [PATCH edk2-platforms] Platform/AMD/OverdriveBoard: fix byte order of default MAC addresses
afish at apple.com
Mon Dec 10 15:38:30 PST 2018
> On Dec 10, 2018, at 3:33 PM, Leif Lindholm <leif.lindholm at linaro.org> wrote:
> On Mon, Dec 10, 2018 at 11:51:43PM +0100, Ard Biesheuvel wrote:
>> On Mon, 10 Dec 2018 at 23:14, Leif Lindholm <leif.lindholm at linaro.org> wrote:
>>> On Wed, Dec 05, 2018 at 09:10:48PM +0100, Ard Biesheuvel wrote:
>>>> The PCDs containing the default MAC addresses are of type UINT64,
>>>> and so the byte order needs to be inverted. As they are currently,
>>>> both default MAC addresses are invalid since they have the multicast
>>>> bit set.
>>> Ah, oops.
>>> That would also prevent them from being "locally administered" and
>>> hence permissible without registering an entry in the OUI.
>>> However, to reduce someone interpreting the _new_ values that way
>>> instead, could you do one of:
>>> - Adding a comment explaining these are in reverse byte order.
>>> - Convert them to the new Array type PCD, to make the bytes appear
>>> in natural order?
>>>  edk2 72a1d77694d51914c0dd6aa97dbfa58634b0a4a5
>> How does one refer to such a PCD from C code?
> Good question :)
Seems like you would need cast the pointer to the data structure in the C code. If I understand correctly the change in the PCD creation code is you can now better structure the data, but it is no different on the consumer end and you got a blob of bytes in both cases.
>>>> Contributed-under: TianoCore Contribution Agreement 1.1
>>>> Signed-off-by: Ard Biesheuvel <ard.biesheuvel at linaro.org>
>>>> Platform/AMD/OverdriveBoard/OverdriveBoard.dsc | 4 ++--
>>>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>>> diff --git a/Platform/AMD/OverdriveBoard/OverdriveBoard.dsc b/Platform/AMD/OverdriveBoard/OverdriveBoard.dsc
>>>> index 05433d4472e8..2843e51f93f7 100644
>>>> --- a/Platform/AMD/OverdriveBoard/OverdriveBoard.dsc
>>>> +++ b/Platform/AMD/OverdriveBoard/OverdriveBoard.dsc
>>>> @@ -469,8 +469,8 @@ DEFINE DO_CAPSULE = FALSE
>>>> - gAmdStyxTokenSpaceGuid.PcdEthMacA|0x02A1A2A3A4A5
>>>> - gAmdStyxTokenSpaceGuid.PcdEthMacB|0x02B1B2B3B4B5
>>>> + gAmdStyxTokenSpaceGuid.PcdEthMacA|0xA5A4A3A2A102
>>>> + gAmdStyxTokenSpaceGuid.PcdEthMacB|0xB5B4B3B2B102
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