On Fri, May 22, 2020 at 4:43 AM Kees Cook <keescook@xxxxxxxxxxxx> wrote: > > On Wed, May 20, 2020 at 11:20:10AM -0700, 'Fangrui Song' via Clang Built Linux wrote: > > In the latest efi tree, ce5e3f909fc0ed67e58367b9c56a54c20a51080b > > "efi/printf: Add 64-bit and 8-bit integer support", > > arch/x86/boot/compressed/vmlinux may have an undesired > > .discard.unreachable section from drivers/firmware/efi/libstub/vsprintf.stub.o > > > > .discard.unreachable contains an R_X86_64_PC32 relocation, which will be > > warned by LLD: a non-SHF_ALLOC section (.discard.unreachable) is not > > part of the memory image, thus conceptually the distance between a > > non-SHF_ALLOC and a SHF_ALLOC is not a constant which can be resolved at > > link time. > > > > % ld.lld -m elf_x86_64 -T arch/x86/boot/compressed/vmlinux.lds ... -o arch/x86/boot/compressed/vmlinux > > ld.lld: warning: vsprintf.c:(.discard.unreachable+0x0): has non-ABS relocation R_X86_64_PC32 against symbol '' > > > > Reuse the DISCARDS macro which includes .discard.* to drop .discard.unreachable > > > > Reported-by: kbuild test robot <lkp@xxxxxxxxx> > > Signed-off-by: Fangrui Song <maskray@xxxxxxxxxx> > > Yay macro usage! :) > > Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx> > Feel free to add... Tested-by: Sedat Dilek <sedat.dilek@xxxxxxxxx> # build and boot on Linux v5.7-rc6+ with Clang and LLD v10.0.1-rc1 ...together with one more patches in the x86/boot area: x86/boot: Correct relocation destination on old linkers Next run will include: x86/boot: Add .text.startup to setup.ld (v2) - Sedat - [1] https://github.com/llvm/llvm-project/releases/tag/llvmorg-10.0.1-rc1
