On Sun, 7 Nov 2021 at 08:58, Ard Biesheuvel <ardb@xxxxxxxxxx> wrote: > > On Sun, 7 Nov 2021 at 05:24, Seed Of Onan <seedofonan@xxxxxxxxx> wrote: > > > > > IIUC, the issue is in > > > config EFI_STUB > > > : > > > depends on $(cc-option,-mabi=ms) || X86_32 > > > where the cc-option check is failing due to the use of > > > -mx32 for the core kernel, whereas the EFI stub will be > > > built with -m64 regardless. > > Yes, except, the kernel can't be built with -mx32, only -m32 or -m64. The -m64 option gets added to the compile flags in arch/x86/Makefile on 64bit builds. > > > > Right, so it is just the compiler default > > > > Given that __attribute__((ms_abi)) should be supported on any > > > GCC versions 4.8 or newer, I think we can just drop this > > > depends line entirely. Would that solve your issue? > > Yes it would, but it sure seems to me to be the wrong way -- gcc is not the only compiler, and the ms calling convention isn't required to build the kernel otherwise, is it? > > > > I don't follow. All compilers that we support implement this so why test for it? > > > I found in scripts/Kconfig.include a variable that is "-m64 if the compiler supports it, or an empty string otherwise": > > depends on $(cc-option,$(m64-flag) -mabi=ms) || X86_32 > > > > I don't get the "|| X86_32" part -- can it really be that when building an x86_32 kernel, there is no concern about the support for the calling convention needed by the efi stub? But whatever. > > Of course we care about the calling convention. Why would you think > that we don't? Note that 32-bit UEFI code uses __attribute__((regparm(0))) as the calling convention not ms_abi
