Hi Tor,
On 6/10/2021 2:28 AM, torvic9@xxxxxxxxxxx wrote:
Since LLVM commit 3787ee4, the '-stack-alignment' flag has been dropped [1],
leading to the following error message when building a LTO kernel with
Clang-13 and LLD-13:
ld.lld: error: -plugin-opt=-: ld.lld: Unknown command line argument
'-stack-alignment=8'. Try 'ld.lld --help'
ld.lld: Did you mean '--stackrealign=8'?
It also appears that the '-code-model' flag is not necessary anymore starting
with LLVM-9 [2].
Drop '-code-model' and make '-stack-alignment' conditional on LLD < 13.0.0.
This is for linux-stable 5.12.
Another patch will be submitted for 5.13 shortly (unless there are objections).
This patch needs to be accepted into mainline first before it can go to
stable so this line needs to be removed. The rest of the description
looks good to me, good job on being descriptive!
Discussion: https://github.com/ClangBuiltLinux/linux/issues/1377
[1]: https://reviews.llvm.org/D103048
[2]: https://reviews.llvm.org/D52322
As Greg's auto-response points out, there needs to be an actual
Cc: stable@xxxxxxxxxxxxxxx
here in the patch, rather than just cc'ing stable@xxxxxxxxxxxxxxx
through email.
Signed-off-by: Tor Vic <torvic9@xxxxxxxxxxx>
The actual patch itself looks good and I have verified that it fixes the
build error. On the resend with the above fixed, please feel free to add:
Reviewed-by: Nathan Chancellor <nathan@xxxxxxxxxx>
Tested-by: Nathan Chancellor <nathan@xxxxxxxxxx>
---
arch/x86/Makefile | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index 1f2e5bf..2855a1a 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -192,8 +192,9 @@ endif
KBUILD_LDFLAGS += -m elf_$(UTS_MACHINE)
ifdef CONFIG_LTO_CLANG
-KBUILD_LDFLAGS += -plugin-opt=-code-model=kernel \
- -plugin-opt=-stack-alignment=$(if $(CONFIG_X86_32),4,8)
+ifeq ($(shell test $(CONFIG_LLD_VERSION) -lt 130000; echo $$?),0)
+KBUILD_LDFLAGS += -plugin-opt=-stack-alignment=$(if $(CONFIG_X86_32),4,8)
+endif
endif
ifdef CONFIG_X86_NEED_RELOCS
Cheers,
Nathan
