From: Arnd Bergmann <arnd@kernel.org>
To: Sami Tolvanen <samitolvanen@google.com>
Cc: Masahiro Yamada <masahiroy@kernel.org>,
Steven Rostedt <rostedt@goodmis.org>,
Will Deacon <will@kernel.org>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"Paul E. McKenney" <paulmck@kernel.org>,
Kees Cook <keescook@chromium.org>,
Nick Desaulniers <ndesaulniers@google.com>,
clang-built-linux <clang-built-linux@googlegroups.com>,
Kernel Hardening <kernel-hardening@lists.openwall.com>,
linux-arch <linux-arch@vger.kernel.org>,
Linux ARM <linux-arm-kernel@lists.infradead.org>,
Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
linux-pci <linux-pci@vger.kernel.org>
Subject: Re: [PATCH v8 00/16] Add support for Clang LTO
Date: Tue, 8 Dec 2020 17:56:13 +0100 [thread overview]
Message-ID: <CAK8P3a32HwzZYDK3i68fY0JLGCj18RH1iDMq70OZpTrsopyCcw@mail.gmail.com> (raw)
In-Reply-To: <CABCJKudbCD3s0RcSVzbnn4MV=DadKOxOxar3jfiPWucX4JGxCg@mail.gmail.com>
On Tue, Dec 8, 2020 at 5:53 PM 'Sami Tolvanen' via Clang Built Linux
<clang-built-linux@googlegroups.com> wrote:
>
> > A small update here: I see this behavior with every single module
> > build, including 'tinyconfig' with one module enabled, and 'defconfig'.
>
> The .o file here is a thin archive of the bitcode files for the
> module. We compile .lto.o from that before modpost, because we need an
> ELF binary to process, and then reuse the .lto.o file when linking the
> final module.
>
> At no point should we link the .o file again, especially not with
> .lto.o, because that would clearly cause every symbol to be
> duplicated, so I'm not sure what goes wrong here. Here's the relevant
> part of scripts/Makefile.modfinal:
>
> ifdef CONFIG_LTO_CLANG
> # With CONFIG_LTO_CLANG, reuse the object file we compiled for modpost to
> # avoid a second slow LTO link
> prelink-ext := .lto
> ...
> $(modules): %.ko: %$(prelink-ext).o %.mod.o scripts/module.lds FORCE
> +$(call if_changed,ld_ko_o)
Ah, it's probably a local problem now, as I had a merge conflict against
linux-next in this Makefile and I must have resolved the conflict incorrectly.
Arnd
WARNING: multiple messages have this Message-ID (diff)
From: Arnd Bergmann <arnd@kernel.org>
To: Sami Tolvanen <samitolvanen@google.com>
Cc: linux-arch <linux-arch@vger.kernel.org>,
Kees Cook <keescook@chromium.org>,
"Paul E. McKenney" <paulmck@kernel.org>,
Kernel Hardening <kernel-hardening@lists.openwall.com>,
Peter Zijlstra <peterz@infradead.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Masahiro Yamada <masahiroy@kernel.org>,
Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>,
Nick Desaulniers <ndesaulniers@google.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Steven Rostedt <rostedt@goodmis.org>,
clang-built-linux <clang-built-linux@googlegroups.com>,
linux-pci <linux-pci@vger.kernel.org>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Will Deacon <will@kernel.org>,
Linux ARM <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH v8 00/16] Add support for Clang LTO
Date: Tue, 8 Dec 2020 17:56:13 +0100 [thread overview]
Message-ID: <CAK8P3a32HwzZYDK3i68fY0JLGCj18RH1iDMq70OZpTrsopyCcw@mail.gmail.com> (raw)
In-Reply-To: <CABCJKudbCD3s0RcSVzbnn4MV=DadKOxOxar3jfiPWucX4JGxCg@mail.gmail.com>
On Tue, Dec 8, 2020 at 5:53 PM 'Sami Tolvanen' via Clang Built Linux
<clang-built-linux@googlegroups.com> wrote:
>
> > A small update here: I see this behavior with every single module
> > build, including 'tinyconfig' with one module enabled, and 'defconfig'.
>
> The .o file here is a thin archive of the bitcode files for the
> module. We compile .lto.o from that before modpost, because we need an
> ELF binary to process, and then reuse the .lto.o file when linking the
> final module.
>
> At no point should we link the .o file again, especially not with
> .lto.o, because that would clearly cause every symbol to be
> duplicated, so I'm not sure what goes wrong here. Here's the relevant
> part of scripts/Makefile.modfinal:
>
> ifdef CONFIG_LTO_CLANG
> # With CONFIG_LTO_CLANG, reuse the object file we compiled for modpost to
> # avoid a second slow LTO link
> prelink-ext := .lto
> ...
> $(modules): %.ko: %$(prelink-ext).o %.mod.o scripts/module.lds FORCE
> +$(call if_changed,ld_ko_o)
Ah, it's probably a local problem now, as I had a merge conflict against
linux-next in this Makefile and I must have resolved the conflict incorrectly.
Arnd
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next prev parent reply other threads:[~2020-12-08 16:57 UTC|newest]
Thread overview: 141+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-01 21:36 [PATCH v8 00/16] Add support for Clang LTO Sami Tolvanen
2020-12-01 21:36 ` Sami Tolvanen
2020-12-01 21:36 ` Sami Tolvanen
2020-12-01 21:36 ` [PATCH v8 01/16] tracing: move function tracer options to Kconfig Sami Tolvanen
2020-12-01 21:36 ` Sami Tolvanen
2020-12-01 21:36 ` Sami Tolvanen
2020-12-01 21:47 ` Steven Rostedt
2020-12-01 21:47 ` Steven Rostedt
2020-12-01 21:36 ` [PATCH v8 02/16] kbuild: add support for Clang LTO Sami Tolvanen
2020-12-01 21:36 ` Sami Tolvanen
2020-12-01 21:36 ` Sami Tolvanen
2020-12-02 2:59 ` Masahiro Yamada
2020-12-02 2:59 ` Masahiro Yamada
2020-12-03 0:07 ` Nick Desaulniers
2020-12-03 0:07 ` Nick Desaulniers
2020-12-03 0:07 ` Nick Desaulniers
2020-12-01 21:36 ` [PATCH v8 03/16] kbuild: lto: fix module versioning Sami Tolvanen
2020-12-01 21:36 ` Sami Tolvanen
2020-12-01 21:36 ` Sami Tolvanen
2020-12-01 21:36 ` [PATCH v8 04/16] kbuild: lto: limit inlining Sami Tolvanen
2020-12-01 21:36 ` Sami Tolvanen
2020-12-01 21:36 ` Sami Tolvanen
2020-12-01 21:36 ` [PATCH v8 05/16] kbuild: lto: merge module sections Sami Tolvanen
2020-12-01 21:36 ` Sami Tolvanen
2020-12-01 21:36 ` Sami Tolvanen
2020-12-01 21:36 ` [PATCH v8 06/16] kbuild: lto: remove duplicate dependencies from .mod files Sami Tolvanen
2020-12-01 21:36 ` Sami Tolvanen
2020-12-01 21:36 ` Sami Tolvanen
2020-12-01 21:36 ` [PATCH v8 07/16] init: lto: ensure initcall ordering Sami Tolvanen
2020-12-01 21:36 ` Sami Tolvanen
2020-12-01 21:36 ` Sami Tolvanen
2020-12-01 21:36 ` [PATCH v8 08/16] init: lto: fix PREL32 relocations Sami Tolvanen
2020-12-01 21:36 ` Sami Tolvanen
2020-12-01 21:36 ` Sami Tolvanen
2020-12-01 21:37 ` [PATCH v8 09/16] PCI: Fix PREL32 relocations for LTO Sami Tolvanen
2020-12-01 21:37 ` Sami Tolvanen
2020-12-01 21:37 ` Sami Tolvanen
2020-12-01 21:37 ` [PATCH v8 10/16] modpost: lto: strip .lto from module names Sami Tolvanen
2020-12-01 21:37 ` Sami Tolvanen
2020-12-01 21:37 ` Sami Tolvanen
2020-12-01 21:37 ` [PATCH v8 11/16] scripts/mod: disable LTO for empty.c Sami Tolvanen
2020-12-01 21:37 ` Sami Tolvanen
2020-12-01 21:37 ` Sami Tolvanen
2020-12-01 21:37 ` [PATCH v8 12/16] efi/libstub: disable LTO Sami Tolvanen
2020-12-01 21:37 ` Sami Tolvanen
2020-12-01 21:37 ` Sami Tolvanen
2020-12-01 21:37 ` [PATCH v8 13/16] drivers/misc/lkdtm: disable LTO for rodata.o Sami Tolvanen
2020-12-01 21:37 ` Sami Tolvanen
2020-12-01 21:37 ` Sami Tolvanen
2020-12-01 21:37 ` [PATCH v8 14/16] arm64: vdso: disable LTO Sami Tolvanen
2020-12-01 21:37 ` Sami Tolvanen
2020-12-01 21:37 ` Sami Tolvanen
2020-12-01 21:37 ` [PATCH v8 15/16] arm64: disable recordmcount with DYNAMIC_FTRACE_WITH_REGS Sami Tolvanen
2020-12-01 21:37 ` Sami Tolvanen
2020-12-01 21:37 ` Sami Tolvanen
2020-12-01 21:37 ` [PATCH v8 16/16] arm64: allow LTO to be selected Sami Tolvanen
2020-12-01 21:37 ` Sami Tolvanen
2020-12-01 21:37 ` Sami Tolvanen
2020-12-03 0:01 ` [PATCH v8 00/16] Add support for Clang LTO Nick Desaulniers
2020-12-03 0:01 ` Nick Desaulniers
2020-12-03 0:01 ` Nick Desaulniers
2020-12-03 11:26 ` Will Deacon
2020-12-03 11:26 ` Will Deacon
2020-12-03 17:07 ` Sami Tolvanen
2020-12-03 17:07 ` Sami Tolvanen
2020-12-03 17:07 ` Sami Tolvanen
2020-12-03 18:21 ` Nathan Chancellor
2020-12-03 18:21 ` Nathan Chancellor
2020-12-03 18:22 ` Will Deacon
2020-12-03 18:22 ` Will Deacon
2020-12-03 22:32 ` Nick Desaulniers
2020-12-03 22:32 ` Nick Desaulniers
2020-12-03 22:32 ` Nick Desaulniers
2020-12-04 9:35 ` Will Deacon
2020-12-04 9:35 ` Will Deacon
2020-12-04 22:52 ` Sami Tolvanen
2020-12-04 22:52 ` Sami Tolvanen
2020-12-04 22:52 ` Sami Tolvanen
2020-12-06 6:50 ` Nathan Chancellor
2020-12-06 6:50 ` Nathan Chancellor
2020-12-06 20:09 ` Sami Tolvanen
2020-12-06 20:09 ` Sami Tolvanen
2020-12-06 20:09 ` Sami Tolvanen
2020-12-08 0:46 ` Nathan Chancellor
2020-12-08 0:46 ` Nathan Chancellor
2020-12-08 12:15 ` Arnd Bergmann
2020-12-08 12:15 ` Arnd Bergmann
2020-12-08 12:15 ` Arnd Bergmann
2020-12-08 13:54 ` Arnd Bergmann
2020-12-08 13:54 ` Arnd Bergmann
2020-12-08 13:54 ` Arnd Bergmann
2020-12-08 16:53 ` Sami Tolvanen
2020-12-08 16:53 ` Sami Tolvanen
2020-12-08 16:53 ` Sami Tolvanen
2020-12-08 16:56 ` Arnd Bergmann [this message]
2020-12-08 16:56 ` Arnd Bergmann
2020-12-08 16:56 ` Arnd Bergmann
2020-12-08 16:43 ` Sami Tolvanen
2020-12-08 16:43 ` Sami Tolvanen
2020-12-08 16:43 ` Sami Tolvanen
2020-12-08 20:59 ` Arnd Bergmann
2020-12-08 20:59 ` Arnd Bergmann
2020-12-08 21:02 ` Arnd Bergmann
2020-12-08 21:02 ` Arnd Bergmann
2020-12-09 5:23 ` Fāng-ruì Sòng
2020-12-09 5:23 ` Fāng-ruì Sòng
2020-12-09 5:23 ` Fāng-ruì Sòng
2020-12-09 9:07 ` Arnd Bergmann
2020-12-09 9:07 ` Arnd Bergmann
2020-12-09 9:07 ` Arnd Bergmann
2020-12-09 9:59 ` Arnd Bergmann
2020-12-09 9:59 ` Arnd Bergmann
2020-12-09 16:09 ` Sami Tolvanen
2020-12-09 16:09 ` Sami Tolvanen
2020-12-09 16:09 ` Sami Tolvanen
2020-12-09 19:24 ` Arnd Bergmann
2020-12-09 19:24 ` Arnd Bergmann
2020-12-09 19:24 ` Arnd Bergmann
2020-12-08 21:09 ` Nick Desaulniers
2020-12-08 21:09 ` Nick Desaulniers
2020-12-08 21:09 ` Nick Desaulniers
2020-12-08 22:20 ` Arnd Bergmann
2020-12-08 22:20 ` Arnd Bergmann
2020-12-08 22:20 ` Arnd Bergmann
2020-12-09 16:11 ` Sami Tolvanen
2020-12-09 16:11 ` Sami Tolvanen
2020-12-09 16:11 ` Sami Tolvanen
2020-12-09 4:55 ` Fangrui Song
2020-12-09 4:55 ` Fangrui Song
2020-12-09 9:19 ` Arnd Bergmann
2020-12-09 9:19 ` Arnd Bergmann
2020-12-09 9:19 ` Arnd Bergmann
2020-12-09 12:35 ` Arnd Bergmann
2020-12-09 12:35 ` Arnd Bergmann
2020-12-09 12:35 ` Arnd Bergmann
2020-12-09 16:25 ` Sami Tolvanen
2020-12-09 16:25 ` Sami Tolvanen
2020-12-09 16:25 ` Sami Tolvanen
2020-12-09 17:51 ` Arnd Bergmann
2020-12-09 17:51 ` Arnd Bergmann
2020-12-09 17:51 ` Arnd Bergmann
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