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

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

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>