From: Nathan Chancellor nathan@kernel.org
[ Upstream commit aaeed6ecc1253ce1463fa1aca0b70a4ccbc9fa75 ]
There are two outstanding issues with CONFIG_X86_X32_ABI and llvm-objcopy, with similar root causes:
1. llvm-objcopy does not properly convert .note.gnu.property when going from x86_64 to x86_x32, resulting in a corrupted section when linking:
https://github.com/ClangBuiltLinux/linux/issues/1141
2. llvm-objcopy produces corrupted compressed debug sections when going from x86_64 to x86_x32, also resulting in an error when linking:
https://github.com/ClangBuiltLinux/linux/issues/514
After commit 41c5ef31ad71 ("x86/ibt: Base IBT bits"), the .note.gnu.property section is always generated when CONFIG_X86_KERNEL_IBT is enabled, which causes the first issue to become visible with an allmodconfig build:
ld.lld: error: arch/x86/entry/vdso/vclock_gettime-x32.o:(.note.gnu.property+0x1c): program property is too short
To avoid this error, do not allow CONFIG_X86_X32_ABI to be selected when using llvm-objcopy. If the two issues ever get fixed in llvm-objcopy, this can be turned into a feature check.
Signed-off-by: Nathan Chancellor nathan@kernel.org Signed-off-by: Peter Zijlstra (Intel) peterz@infradead.org Link: https://lore.kernel.org/r/20220314194842.3452-3-nathan@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- arch/x86/Kconfig | 5 +++++ 1 file changed, 5 insertions(+)
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 9f5bd41bf660..d0ecc4005df3 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -2837,6 +2837,11 @@ config IA32_AOUT config X86_X32 bool "x32 ABI for 64-bit mode" depends on X86_64 + # llvm-objcopy does not convert x86_64 .note.gnu.property or + # compressed debug sections to x86_x32 properly: + # https://github.com/ClangBuiltLinux/linux/issues/514 + # https://github.com/ClangBuiltLinux/linux/issues/1141 + depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm) help Include code to run binaries for the x32 native 32-bit ABI for 64-bit processors. An x32 process gets access to the