Re: [PATCH v4 0/6] UefiCpuPkg, OvmfPkg: Simplify CpuExceptionHandlerLib

["Marvin Häuser" <mhaeuser@posteo.de>]

FWIW, Reviewed-by: Marvin Häuser <mhaeuser@posteo.de>

> On 3. Apr 2023, at 16:29, Ard Biesheuvel <ardb@kernel.org> wrote:
> 
> 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:
> - Add another patch to move PeiCpuExceptionHandlerLib to SEC/PEI version
>  of the NASM source file
> - Improve commit logs
> 
> Changes since v2:
> -  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 v1:
> - pass linker switches to permit absolute relocations in read-only
>  regions, and keep all code in .text
> 
> Cc: "Ni, Ray" <ray.ni@intel.com>
> Cc: Andrew Fish <afish@apple.com>
> Cc: "Kinney, Michael D" <michael.d.kinney@intel.com>
> Cc: "Liu, Zhiguang" <zhiguang.liu@intel.com>
> Cc: Rebecca Cran <rebecca@bsdio.com>
> Cc: Tom Lendacky <thomas.lendacky@amd.com>
> Cc: Marvin Häuser <mhaeuser@posteo.de>
> 
> Ard Biesheuvel (6):
>  BaseTools/tools_def CLANGDWARF: Permit text relocations
>  UefiCpuPkg/CpuExceptionHandlerLib: Use single SEC/PEI version
>  UefiCpuPkg/PeiCpuExceptionHandlerLib: Use SEC/PEI specific asm
>    component
>  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.inf                                          |   5 +-
> UefiCpuPkg/Library/CpuExceptionHandlerLib/PeiCpuExceptionHandlerLib.inf                                          |   4 +-
> UefiCpuPkg/Library/CpuExceptionHandlerLib/SecPeiCpuExceptionHandlerLib.inf                                       |   4 +-
> UefiCpuPkg/Library/CpuExceptionHandlerLib/SmmCpuExceptionHandlerLib.inf                                          |   4 +-
> UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/ExceptionHandlerAsm.nasm                                           | 116 +++++++++++++++++---
> UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/{Xcode5ExceptionHandlerAsm.nasm => SecPeiExceptionHandlerAsm.nasm} | 108 +++---------------
> UefiCpuPkg/Library/CpuExceptionHandlerLib/Xcode5SecPeiCpuExceptionHandlerLib.inf                                 |  65 -----------
> UefiCpuPkg/Library/CpuExceptionHandlerLib/Xcode5SecPeiCpuExceptionHandlerLib.uni                                 |  18 ---
> UefiCpuPkg/UefiCpuPkg.dsc                                                                                        |   7 --
> 18 files changed, 133 insertions(+), 232 deletions(-)
> rename UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/{Xcode5ExceptionHandlerAsm.nasm => SecPeiExceptionHandlerAsm.nasm} (70%)
> delete mode 100644 UefiCpuPkg/Library/CpuExceptionHandlerLib/Xcode5SecPeiCpuExceptionHandlerLib.inf
> delete mode 100644 UefiCpuPkg/Library/CpuExceptionHandlerLib/Xcode5SecPeiCpuExceptionHandlerLib.uni
> 
> -- 
> 2.39.2
>