Re: [PATCH 2/3] BaseTools/Conf/tools_def: Fix CLANGDWARF_IA32_X64

["Ni, Ray" <ray.ni@intel.com>]

Why ELF header overflows into .text section?

> -----Original Message-----
> From: Patrick Rudolph <patrick.rudolph@9elements.com>
> Sent: Friday, March 17, 2023 10:06 PM
> Cc: devel@edk2.groups.io; Dong, Guo <guo.dong@intel.com>; Guo, Gua
> <gua.guo@intel.com>; Lu, James <james.lu@intel.com>; Ni, Ray
> <ray.ni@intel.com>; mhaeuser@posteo.de; ardb@kernel.org
> Subject: [PATCH 2/3] BaseTools/Conf/tools_def: Fix
> CLANGDWARF_IA32_X64
> 
> Drop the "-z max-page-size=0x40" option as it causes the ELF
> header to overflow into the .text section, causing undefined
> behaviour.
> 
> With high optimization level it corrupts essential code and
> the binary would crash. It might work with low optimization
> level though. As the default is to use Oz and LTO, it always
> crashes.
> 
> Test:
> The ELF generated by
> 'python UefiPayloadPkg/UniversalPayloadBuild.py -a IA32' boots.
> 
> Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
> Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=4357
> ---
>  BaseTools/Conf/tools_def.template | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/BaseTools/Conf/tools_def.template
> b/BaseTools/Conf/tools_def.template
> index 9b59bd75c3..0c584ab390 100755
> --- a/BaseTools/Conf/tools_def.template
> +++ b/BaseTools/Conf/tools_def.template
> @@ -2866,7 +2866,7 @@ DEFINE CLANGDWARF_X64_PREFIX        =
> ENV(CLANG_BIN)
> 
> 
>  # LLVM/CLANG doesn't support -n link option. So, it can't share the same
> IA32_X64_DLINK_COMMON flag.
> 
>  # LLVM/CLANG doesn't support common page size. So, it can't share the
> same GccBase.lds script.
> 
> -DEFINE CLANGDWARF_IA32_X64_DLINK_COMMON   = -nostdlib -Wl,-q,--gc-
> sections -z max-page-size=0x40
> 
> +DEFINE CLANGDWARF_IA32_X64_DLINK_COMMON   = -nostdlib -Wl,-q,--
> gc-sections
> 
>  DEFINE CLANGDWARF_DLINK2_FLAGS_COMMON     = -Wl,--
> script=$(EDK_TOOLS_PATH)/Scripts/ClangBase.lds
> 
>  DEFINE CLANGDWARF_IA32_X64_ASLDLINK_FLAGS =
> DEF(CLANGDWARF_IA32_X64_DLINK_COMMON) -Wl,--
> defsym=PECOFF_HEADER_SIZE=0
> DEF(CLANGDWARF_DLINK2_FLAGS_COMMON) -Wl,--
> entry,ReferenceAcpiTable -u ReferenceAcpiTable
> 
>  DEFINE CLANGDWARF_IA32_X64_DLINK_FLAGS    =
> DEF(CLANGDWARF_IA32_X64_DLINK_COMMON) -Wl,--
> entry,$(IMAGE_ENTRY_POINT) -u $(IMAGE_ENTRY_POINT) -Wl,-
> Map,$(DEST_DIR_DEBUG)/$(BASE_NAME).map,--whole-archive
> 
> --
> 2.39.1