This is a note to let you know that I've just added the patch titled
x86, lto: Pass -stack-alignment only on LLD < 13.0.0
to the 5.12-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
x86-lto-pass-stack-alignment-only-on-lld-13.0.0.patch
and it can be found in the queue-5.12 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 2398ce80152aae33b9501ef54452e09e8e8d4262 Mon Sep 17 00:00:00 2001
From: Tor Vic <torvic9@xxxxxxxxxxx>
Date: Thu, 10 Jun 2021 20:58:06 +0000
Subject: x86, lto: Pass -stack-alignment only on LLD < 13.0.0
From: Tor Vic <torvic9@xxxxxxxxxxx>
commit 2398ce80152aae33b9501ef54452e09e8e8d4262 upstream.
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.
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.
[1] https://reviews.llvm.org/D103048
[2] https://reviews.llvm.org/D52322
Cc: stable@xxxxxxxxxxxxxxx
Link: https://github.com/ClangBuiltLinux/linux/issues/1377
Signed-off-by: Tor Vic <torvic9@xxxxxxxxxxx>
Reviewed-by: Nathan Chancellor <nathan@xxxxxxxxxx>
Tested-by: Nathan Chancellor <nathan@xxxxxxxxxx>
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
Link: https://lore.kernel.org/r/f2c018ee-5999-741e-58d4-e482d5246067@xxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/Makefile | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
--- 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
Patches currently in stable-queue which might be from torvic9@xxxxxxxxxxx are
queue-5.12/x86-lto-pass-stack-alignment-only-on-lld-13.0.0.patch
