Re: [edk2-devel] On integrating LoongArch EDK2 firmware into QEMU build process

["Chao Li" <lichao@loongson.cn>]

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在 2023/4/3 19:04, Gerd Hoffmann 写道:

> On Mon, Apr 03, 2023 at 10:29:52AM +0000, Michael Brown wrote:
>> On 03/04/2023 11:13, Chao Li wrote:
>>> This problem is because the gcc-12 does not yet to support the option
>>> 'mno-explicit-reloc', this option is used to open the new reloaction
>>> type for LoongArch, this new feature is very important for LoongArch,
>>> because it can reduce the binary size and improve code execution
>>> efficiency, so we turn it on when submitting the code to the EDK2 repo.
>> Is it possible to produce a _functional_ LoongArch64 EDK2 binary without
>> this option, even if the resulting binary is less efficient?
> MdePkg/Include/IndustryStandard/PeImage.h lists a single loongarch
> relocation type only, which I expect being the new type.  So I suspect
> the answer is "no" because the edk2 pe loader isn't able to handle the
> old relocation type(s).

Yes, the answer is "no", but the opposite is ture, the 
MdePkg/Include/IndustryStandard/PeImage.h LoongArch relocation type is 
older, this type appears in this list for compatiblility with binaries 
using the old reloaction type. If you use this type, you have to turn on 
the option '-mla-global-with-abs' in gcc,all global symbols will be 
created as "mark la" type, PE loader will use this rule to handle them. 
This option is mutually exclusive with 'mno-explicit-reloc',  new 
reloaction type(s) doesn't require special type(s) to be expressed in 
PeImage.h, PE loader doesn't need to do anything about relocation, all 
of reloaction process is done in BaseTools/Source/C/GenFw/Elf64Convert.c.


Thanks,
Chao
在 2023/4/3 19:04, Gerd Hoffmann 写道:
> On Mon, Apr 03, 2023 at 10:29:52AM +0000, Michael Brown wrote:
>> On 03/04/2023 11:13, Chao Li wrote:
>>> This problem is because the gcc-12 does not yet to support the option
>>> 'mno-explicit-reloc', this option is used to open the new reloaction
>>> type for LoongArch, this new feature is very important for LoongArch,
>>> because it can reduce the binary size and improve code execution
>>> efficiency, so we turn it on when submitting the code to the EDK2 repo.
>> Is it possible to produce a _functional_ LoongArch64 EDK2 binary without
>> this option, even if the resulting binary is less efficient?
> MdePkg/Include/IndustryStandard/PeImage.h lists a single loongarch
> relocation type only, which I expect being the new type.  So I suspect
> the answer is "no" because the edk2 pe loader isn't able to handle the
> old relocation type(s).
>
> take care,
>    Gerd
>
>
>
> 
>

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