On 10.06.21 19:20, Nick Desaulniers wrote: > On Thu, Jun 10, 2021 at 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. > > 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@xxxxxxxxxxx> >> --- >> 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 > > >
