Ard,
What does "-read_only_relocs suppress" control?
Linker doesn't produce relocation entries that modifies .text section silently
so the final .text just cannot run at all?
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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