Hi Ray,
> On 31. Mar 2023, at 12:09, Ni, Ray <ray...@intel.com> wrote:
>
> Ard,
> What does "-read_only_relocs suppress" control?
It controls whether relocs that target read-only segments yield a build error
or not. I think lld uses “-z notext”.
> Linker doesn't produce relocation entries that modifies .text section silently
> so the final .text just cannot run at all?
Could you please rephrase? I’m not sure I understand, but I think it’s
important everyone understands the issues at play to make a good judgment call.
Best regards,
Marvin
>
> Thanks,
> Ray
>
>> -----Original Message-----
>> From: devel@edk2.groups.io <devel@edk2.groups.io> On Behalf Of Ard
>> Biesheuvel
>> Sent: Friday, March 31, 2023 5:15 PM
>> To: devel@edk2.groups.io
>> Cc: Ard Biesheuvel <a...@kernel.org>; Ni, Ray <ray...@intel.com>; Andrew
>> Fish <af...@apple.com>; Kinney, Michael D <michael.d.kin...@intel.com>;
>> Liu, Zhiguang <zhiguang....@intel.com>; Rebecca Cran
>> <rebe...@bsdio.com>; Tom Lendacky <thomas.lenda...@amd.com>;
>> Marvin Häuser <mhaeu...@posteo.de>
>> Subject: [edk2-devel] [RFT PATCH v3 0/5] UefiCpuPkg, OvmfPkg: Simplify
>> CpuExceptionHandlerLib
>>
>> We have a special version of CpuExceptionHandlerLib for XCODE5, whose
>>
>> linker (LLD) does not permit absolute symbol references in read-only
>>
>> sections.
>>
>>
>>
>> Instead of fixing this up at runtime for all toolchains (which is done
>>
>> by writing the fixed up values to the .text section, which we'd prefer
>>
>> to avoid), tweak the SEC/PEI version so it does not need this, and
>>
>> update the remaining versions to only incorporate this logic when using
>>
>> the XCODE toolchain.
>>
>>
>>
>> Changes since v3:
>>
>> - As Marvin points out, using '-read_only_relocs suppress' with the X64
>>
>> XCODE linker is a terrible idea, as it corrupts the resulting PE
>>
>> binaries, so instead, let's do the following:
>>
>> . tweak the SEC/PEI version of the library so the relocs are emitted
>>
>> into .data when using XCODE;
>>
>> . tweak the other versions so the runtime fixups are only done when
>>
>> using XCODE
>>
>> - add acks from Jiewen and Ray
>>
>>
>>
>> Changes since v2:
>>
>> - pass linker switches to permit absolute relocations in read-only
>>
>> regions, and keep all code in .text
>>
>>
>>
>> Cc: "Ni, Ray" <ray...@intel.com>
>>
>> Cc: Andrew Fish <af...@apple.com>
>>
>> Cc: "Kinney, Michael D" <michael.d.kin...@intel.com>
>>
>> Cc: "Liu, Zhiguang" <zhiguang....@intel.com>
>>
>> Cc: Rebecca Cran <rebe...@bsdio.com>
>>
>> Cc: Tom Lendacky <thomas.lenda...@amd.com>
>>
>> Cc: Marvin Häuser <mhaeu...@posteo.de>
>>
>>
>>
>> Ard Biesheuvel (5):
>>
>> BaseTools/tools_def CLANGDWARF: Permit text relocations
>>
>> UefiCpuPkg/CpuExceptionHandlerLib: Use single SEC/PEI version
>>
>> UefiCpuPkg/CpuExceptionHandlerLib: Make runtime fixups XCODE-only
>>
>> OvmfPkg: Drop special Xcode5 version of exception handler library
>>
>> UefiCpuPkg/CpuExceptionHandlerLib: Drop special XCODE5 version
>>
>>
>>
>> BaseTools/Conf/tools_def.template
>> | 2 +-
>>
>> OvmfPkg/AmdSev/AmdSevX64.dsc
>> | 4 -
>>
>> OvmfPkg/CloudHv/CloudHvX64.dsc
>> | 4 -
>>
>> OvmfPkg/IntelTdx/IntelTdxX64.dsc
>> |
>> 4 -
>>
>> OvmfPkg/Microvm/MicrovmX64.dsc
>> | 4 -
>>
>> OvmfPkg/OvmfPkgIa32.dsc
>> | 4
>> -
>>
>> OvmfPkg/OvmfPkgIa32X64.dsc
>> |
>> 4 -
>>
>> OvmfPkg/OvmfPkgX64.dsc
>> | 4
>> -
>>
>> OvmfPkg/OvmfXen.dsc
>> | 4 -
>>
>>
>> UefiCpuPkg/Library/CpuExceptionHandlerLib/DxeCpuExceptionHandlerLib.in
>> f | 5 +-
>>
>>
>> UefiCpuPkg/Library/CpuExceptionHandlerLib/PeiCpuExceptionHandlerLib.inf
>> | 4 +-
>>
>>
>> UefiCpuPkg/Library/CpuExceptionHandlerLib/SecPeiCpuExceptionHandlerLib
>> .inf | 4 +-
>>
>>
>> UefiCpuPkg/Library/CpuExceptionHandlerLib/SmmCpuExceptionHandlerLib.i
>> nf | 4 +-
>>
>>
>> UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/ExceptionHandlerAsm.nas
>> m | 116 +++++++++++++++++---
>>
>>
>> UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/{Xcode5ExceptionHandler
>> Asm.nasm => SecPeiExceptionHandlerAsm.nasm} | 108 +++---------------
>>
>>
>> UefiCpuPkg/Library/CpuExceptionHandlerLib/Xcode5SecPeiCpuExceptionHa
>> ndlerLib.inf | 65 -----------
>>
>>
>> UefiCpuPkg/Library/CpuExceptionHandlerLib/Xcode5SecPeiCpuExceptionHa
>> ndlerLib.uni | 18 ---
>>
>> UefiCpuPkg/UefiCpuPkg.dsc
>> | 7
>> --
>>
>> 18 files changed, 133 insertions(+), 232 deletions(-)
>>
>> rename
>> UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/{Xcode5ExceptionHandler
>> Asm.nasm => SecPeiExceptionHandlerAsm.nasm} (70%)
>>
>> delete mode 100644
>> UefiCpuPkg/Library/CpuExceptionHandlerLib/Xcode5SecPeiCpuExceptionHa
>> ndlerLib.inf
>>
>> delete mode 100644
>> UefiCpuPkg/Library/CpuExceptionHandlerLib/Xcode5SecPeiCpuExceptionHa
>> ndlerLib.uni
>>
>>
>>
>> --
>>
>> 2.39.2
>>
>>
>>
>>
>>
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