On Jan 15, 2013, at 9:20 PM, "Tian, Feng" <feng.t...@intel.com> wrote:
> Hi, Andrew > > Which case will have to do this change? If the file format needs a relocation > entry, what it will impact? > It breaks Xcode for X64. "as" -arch x86_64 -g -o /Users/fish/work/edk2TOT/Build/OvmfX64/DEBUG_XCLANG/X64/OvmfPkg/Library/LoadLinuxLib/LoadLinuxLib/OUTPUT/X64/JumpToKernel.obj -I/Users/fish/work/edk2TOT/OvmfPkg/Library/LoadLinuxLib/X64 -I/Users/fish/work/edk2TOT/OvmfPkg/Library/LoadLinuxLib -I/Users/fish/work/edk2TOT/Build/OvmfX64/DEBUG_XCLANG/X64/OvmfPkg/Library/LoadLinuxLib/LoadLinuxLib/DEBUG -I/Users/fish/work/edk2TOT/MdePkg -I/Users/fish/work/edk2TOT/MdePkg/Include -I/Users/fish/work/edk2TOT/MdePkg/Include/X64 -I/Users/fish/work/edk2TOT/OvmfPkg -I/Users/fish/work/edk2TOT/OvmfPkg/Include /Users/fish/work/edk2TOT/Build/OvmfX64/DEBUG_XCLANG/X64/OvmfPkg/Library/LoadLinuxLib/LoadLinuxLib/OUTPUT/X64/JumpToKernel.iii /Users/fish/work/edk2TOT/Build/OvmfX64/DEBUG_XCLANG/X64/OvmfPkg/Library/LoadLinuxLib/LoadLinuxLib/OUTPUT/X64/JumpToKernel.iii:34:32-bit absolute addressing is not supported for x86-64 /Users/fish/work/edk2TOT/Build/OvmfX64/DEBUG_XCLANG/X64/OvmfPkg/Library/LoadLinuxLib/LoadLinuxLib/OUTPUT/X64/JumpToKernel.iii:34:cannot do signed 4 byte relocation The Xcode assembler is more focused on supporting the complier than humans writing assembler, so not all the features are support. If you think about it a 64-bit address is quite large. A %RIP relative address can be encoded in a much smaller space lea 20(%rip), %eax can be encoded in a much smaller instruction and it does not take up a relocation in the PE/COFF image. So I think clang does %RIP relative addressing for X64 vs. encoding 64-bit absolute addressees. Thanks, Andrew Fish > Thanks > Feng > > From: Andrew Fish [mailto:af...@apple.com] > Sent: Wednesday, January 16, 2013 05:58 > To: edk2-devel@lists.sourceforge.net > Subject: [edk2] [Patch] MdeModulePkg: Fix Xcode assembly issue > > Dear MdeModulePkg maintainer, > > Please review this patch that is required to make this file assemble and link > with Xcode. It replaces absolute addressing that requires a relocation entry > with PC relative addressing that does not require a relocation entry. > > Contributed-under: TianoCore Contribution Agreement 1.0 > Signed-off-by: af...@apple.com > > svn diff --diff-cmd diff Universal/Acpi/BootScriptExecutorDxe/X64/S3Asm.S > Index: Universal/Acpi/BootScriptExecutorDxe/X64/S3Asm.S > =================================================================== > --- Universal/Acpi/BootScriptExecutorDxe/X64/S3Asm.S (revision 14050) > +++ Universal/Acpi/BootScriptExecutorDxe/X64/S3Asm.S (working copy) > @@ -18,14 +18,14 @@ > ASM_PFX(AsmTransferControl): > # rcx S3WakingVector :DWORD > # rdx AcpiLowMemoryBase :DWORD > - lea _AsmTransferControl_al_0000, %eax > + lea _AsmTransferControl_al_0000(%rip), %eax > movq $0x2800000000, %r8 > orq %r8, %rax > pushq %rax > shrd $20, %ecx, %ebx > andl $0x0f, %ecx > movw %cx, %bx > - movl %ebx, jmp_addr > + movl %ebx, jmp_addr(%rip) > lret > _AsmTransferControl_al_0000: > .byte 0x0b8, 0x30, 0 # mov ax, 30h as selector > @@ -124,7 +124,7 @@ > popq %rcx > popq %rax # restore all volatile registers > jnz L1 > - jmpq *ASM_PFX(mOriginalHandler) > + jmpq *ASM_PFX(mOriginalHandler)(%rip) > L1: > addq $0x08, %rsp # skip error code for PF > iretq > > > Andrew Fish > > > > > > ------------------------------------------------------------------------------ > Master Java SE, Java EE, Eclipse, Spring, Hibernate, JavaScript, jQuery > and much more. Keep your Java skills current with LearnJavaNow - > 200+ hours of step-by-step video tutorials by Java experts. > SALE $49.99 this month only -- learn more at: > http://p.sf.net/sfu/learnmore_122612 > _______________________________________________ > edk2-devel mailing list > edk2-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/edk2-devel
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