| Message ID | CAKwvOdnGDHn+Y+g5AsKvOFiuF7iVAJ8+x53SgWxH9ejqEZwY9w@mail.gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | 5.4 and 4.19 warning fix for LLVM_IAS | expand |
On Tue, Dec 08, 2020 at 04:43:34PM -0800, Nick Desaulniers wrote: > Dear stable kernel maintainers, > (Woah, two in one day; have I exceeded my limit?) > > Please consider the attached patch for 5.4 and 4.19 for commit > b8a9092330da ("Kbuild: do not emit debug info for assembly with > LLVM_IAS=1"), which fixes a significant number of warnings under arch/ > when assembling a kernel with Clang. I also need a version of this for 5.9.y before we can take this for older kernels. Can you provide that as well? thanks, greg k-h
On Wed, Dec 9, 2020 at 2:58 AM Greg KH <gregkh@linuxfoundation.org> wrote: > > On Tue, Dec 08, 2020 at 04:43:34PM -0800, Nick Desaulniers wrote: > > Dear stable kernel maintainers, > > (Woah, two in one day; have I exceeded my limit?) > > > > Please consider the attached patch for 5.4 and 4.19 for commit > > b8a9092330da ("Kbuild: do not emit debug info for assembly with > > LLVM_IAS=1"), which fixes a significant number of warnings under arch/ > > when assembling a kernel with Clang. > > I also need a version of this for 5.9.y before we can take this for > older kernels. Can you provide that as well? Yes, apologies. It's similar to the 5.4.y patch, but with a shorter set of conflicts as noted in the commit message. Attached. -- Thanks, ~Nick Desaulniers
On Thu, Dec 10, 2020 at 01:21:00PM -0800, Nick Desaulniers wrote: > On Wed, Dec 9, 2020 at 2:58 AM Greg KH <gregkh@linuxfoundation.org> wrote: > > > > On Tue, Dec 08, 2020 at 04:43:34PM -0800, Nick Desaulniers wrote: > > > Dear stable kernel maintainers, > > > (Woah, two in one day; have I exceeded my limit?) > > > > > > Please consider the attached patch for 5.4 and 4.19 for commit > > > b8a9092330da ("Kbuild: do not emit debug info for assembly with > > > LLVM_IAS=1"), which fixes a significant number of warnings under arch/ > > > when assembling a kernel with Clang. > > > > I also need a version of this for 5.9.y before we can take this for > > older kernels. Can you provide that as well? > > Yes, apologies. It's similar to the 5.4.y patch, but with a shorter > set of conflicts as noted in the commit message. Attached. > -- > Thanks, > ~Nick Desaulniers thanks, all now applied. greg k-h
diff --git a/Makefile b/Makefile index e520dee34490..f8c766b35b71 100644 --- a/Makefile +++ b/Makefile @@ -802,8 +802,11 @@ DEBUG_CFLAGS += -gsplit-dwarf else DEBUG_CFLAGS += -g endif +ifneq ($(LLVM_IAS),1) KBUILD_AFLAGS += -Wa,-gdwarf-2 endif +endif + ifdef CONFIG_DEBUG_INFO_DWARF4 DEBUG_CFLAGS += -gdwarf-4 endif
Dear stable kernel maintainers, (Woah, two in one day; have I exceeded my limit?) Please consider the attached patch for 5.4 and 4.19 for commit b8a9092330da ("Kbuild: do not emit debug info for assembly with LLVM_IAS=1"), which fixes a significant number of warnings under arch/ when assembling a kernel with Clang. These backports have already been shipped in Android; I would like to revert them and take them from syncing with stable. CrOS also has the patches staged, but I would prefer for them to sync them from stable as well. b8a9092330da just landed in v5.10-rc7. I recently read https://lwn.net/Articles/838819/, which mentions a discussion about letting patches have more time to soak in mainline, so I accept if your decision is to wait, though I'll note these have been soaking in Android for 2 days shy of one month (Nov 10). There were minor conflicts due to missing Kbuild support for compressed debug info, which is a feature I implemented but don't plan to backport to stable. We plan to use Clang's integrated assembler for Android and CrOS for 4.19+. See also: https://github.com/ClangBuiltLinux/linux/issues/716. -- Thanks, ~Nick Desaulniers From 125bcd1867e6b59f4eb364522276bc273e2648e2 Mon Sep 17 00:00:00 2001 From: Nick Desaulniers <ndesaulniers@google.com> Date: Mon, 9 Nov 2020 10:35:28 -0800 Subject: [PATCH] Kbuild: do not emit debug info for assembly with LLVM_IAS=1 commit b8a9092330da2030496ff357272f342eb970d51b upstream. Clang's integrated assembler produces the warning for assembly files: warning: DWARF2 only supports one section per compilation unit If -Wa,-gdwarf-* is unspecified, then debug info is not emitted for assembly sources (it is still emitted for C sources). This will be re-enabled for newer DWARF versions in a follow up patch. Enables defconfig+CONFIG_DEBUG_INFO to build cleanly with LLVM=1 LLVM_IAS=1 for x86_64 and arm64. Cc: <stable@vger.kernel.org> Link: https://github.com/ClangBuiltLinux/linux/issues/716 Reported-by: Dmitry Golovin <dima@golovin.in> Reported-by: Nathan Chancellor <natechancellor@gmail.com> Suggested-by: Dmitry Golovin <dima@golovin.in> Suggested-by: Nathan Chancellor <natechancellor@gmail.com> Suggested-by: Sedat Dilek <sedat.dilek@gmail.com> Reviewed-by: Fangrui Song <maskray@google.com> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> [nd: backport to avoid conflicts from: commit 10e68b02c861 ("Makefile: support compressed debug info") commit 7b16994437c7 ("Makefile: Improve compressed debug info support detection") commit 695afd3d7d58 ("kbuild: Simplify DEBUG_INFO Kconfig handling")] --- Makefile | 3 +++ 1 file changed, 3 insertions(+)