| From e8663d977af04f63a87d7c68d4035078a3635784 Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Mon, 14 Mar 2022 12:48:42 -0700 |
| Subject: x86/Kconfig: Do not allow CONFIG_X86_X32_ABI=y with llvm-objcopy |
| |
| 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 5c2ccb85f2ef..d377d8af5a9f 100644 |
| --- a/arch/x86/Kconfig |
| +++ b/arch/x86/Kconfig |
| @@ -2827,6 +2827,11 @@ 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 |
| -- |
| 2.35.1 |
| |