Re: [RFT PATCH] efi/x86: move x86 back to libstub

[Maarten Lankhorst <maarten.lankhorst-Z7WLFzj8eWMS+FvcfC7Uqw@public.gmane.org>]

Op 10-10-14 om 10:37 schreef Ard Biesheuvel:
> On 10 October 2014 10:30, Maarten Lankhorst
> <maarten.lankhorst-Z7WLFzj8eWMS+FvcfC7Uqw@public.gmane.org> wrote:
>> Hey,
>>
>> On 10-10-14 08:35, Ard Biesheuvel wrote:
>>> On 6 October 2014 13:06, Ard Biesheuvel <ard.biesheuvel-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org> wrote:
>>>> This reverts commit 84be880560fb, which itself reverted my original
>>>> attempt to move x86 from #include'ing .c files from across the tree
>>>> to using the EFI stub built as a static library.
>>>>
>>>> The issue that affected the original approach was that splitting
>>>> the implementation into several .o files resulted in the variable
>>>> 'efi_early' becoming a global with external linkage, which under
>>>> -fPIC implies that references to it must go through the GOT. However,
>>>> dealing with this additional GOT entry turned out to be troublesome
>>>> on some EFI implementations. (GCC's visibility=hidden attribute is
>>>> supposed to lift this requirement, but it turned out not to work on
>>>> the 32-bit build.)
>>>>
>>>> Instead, use a pure getter function to get a reference to efi_early.
>>>> This approach results in no additional GOT entries being generated,
>>>> so there is no need for any changes in the early GOT handling.
>>>>
>>>> Cc: Maarten Lankhorst <maarten.lankhorst-Z7WLFzj8eWMS+FvcfC7Uqw@public.gmane.org>
>>>> Cc: Josh Boyer <jwboyer-rxtnV0ftBwyoClj4AeEUq9i2O/JbrIOy@public.gmane.org>
>>>> Cc: Linus Torvalds <torvalds-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
>>>> Signed-off-by: Ard Biesheuvel <ard.biesheuvel-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
>>>> ---
>>>>
>>>> Gents,
>>>>
>>>> This is a request for testing: I would like to find out if this patch
>>>> fixes Maarten's issue without breaking anything like it did for Josh
>>>> and Linus the first time around.
>>>>
>>> Any takers?
>> Sorry it was on my todo list but I lost access to my laptop for a while.
>> Normal EFI boot through refind works at least, but I think netboot may use a slightly
>> different codepath which I can't test right now.
>>
>> Tested-By: Maarten Lankhorst <maarten.lankhorst-Z7WLFzj8eWMS+FvcfC7Uqw@public.gmane.org>
> Thanks! So I suppose the code path you did test is the code path that
> produced the failure last time?
>
I tested netboot now to be sure, seems to be working ok.

~Maarten