On 10.06.21 19:20, Nick Desaulniers wrote:
On Thu, Jun 10, 2021 at 2:28 AM torvic9@mailbox.org 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.
Please include this additional context in v2:
These flags were necessary because these flags were not encoded in the IR properly, so the link would restart optimizations without them. Now there are properly encoded in the IR, and these flags exposing implementation details are no longer necessary.That way it doesn't sound like we're not using an 8B stack alignment on x86; we very much are so; AMDGPU GPFs without it!
Will do so. Does this have to be a v2 (with a "changes from v1" info) or just a resend? It is based on mainline now and the line numbers have changed.
Cut the below paragraph out on v2. Thanks for the patch and keep up the good work!
This is for linux-stable 5.12. Another patch will be submitted for 5.13 shortly (unless there are objections).
Discussion: https://github.com/ClangBuiltLinux/linux/issues/1377 [1]: https://reviews.llvm.org/D103048 [2]: https://reviews.llvm.org/D52322
Signed-off-by: Tor Vic torvic9@mailbox.org
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
2.32.0