From: Nick Desaulniers <ndesaulniers@google.com>
To: Masahiro Yamada <masahiroy@kernel.org>
Cc: Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Michal Marek <michal.lkml@markovi.net>,
Sam Ravnborg <sam@ravnborg.org>,
clang-built-linux <clang-built-linux@googlegroups.com>
Subject: Re: [PATCH] kbuild: make Clang build userprogs for target architecture
Date: Mon, 29 Jun 2020 10:38:56 -0700 [thread overview]
Message-ID: <CAKwvOd=qe5KE1vdUYQmpsW2zmDbk5i-MgRujs9B7wqnAj+af0w@mail.gmail.com> (raw)
In-Reply-To: <20200629085911.1676554-1-masahiroy@kernel.org>
On Mon, Jun 29, 2020 at 1:59 AM Masahiro Yamada <masahiroy@kernel.org> wrote:
>
> Programs added 'userprogs' should be compiled for the target
> architecture i.e. the same architecture as the kernel.
>
> GCC does this correctly since the target architecture is implied
> by the toolchain prefix.
>
> Clang builds standalone programs always for the host architecture
> because the target triple is currently missing.
>
> Fix this.
>
> Fixes: 7f3a59db274c ("kbuild: add infrastructure to build userspace programs")
This is a neat feature I didn't know about; looks relatively new.
What's the test case command line invocation to test this with Clang?
> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
> ---
>
> Makefile | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/Makefile b/Makefile
> index 73948798ce3f..cac29cc2ec25 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -970,8 +970,8 @@ LDFLAGS_vmlinux += --pack-dyn-relocs=relr
> endif
>
> # Align the bit size of userspace programs with the kernel
> -KBUILD_USERCFLAGS += $(filter -m32 -m64, $(KBUILD_CFLAGS))
> -KBUILD_USERLDFLAGS += $(filter -m32 -m64, $(KBUILD_CFLAGS))
> +KBUILD_USERCFLAGS += $(filter -m32 -m64 --target=%, $(KBUILD_CFLAGS))
> +KBUILD_USERLDFLAGS += $(filter -m32 -m64 --target=%, $(KBUILD_CFLAGS))
That should be fine.
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
https://www.gnu.org/software/make/manual/html_node/Text-Functions.html
>
> # make the checker run with the right architecture
> CHECKFLAGS += --arch=$(ARCH)
> --
--
Thanks,
~Nick Desaulniers
next prev parent reply other threads:[~2020-06-29 18:57 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-29 8:59 [PATCH] kbuild: make Clang build userprogs for target architecture Masahiro Yamada
2020-06-29 17:38 ` Nick Desaulniers [this message]
2020-06-30 16:23 ` Masahiro Yamada
2020-06-30 19:12 ` Miguel Ojeda
2020-07-05 15:29 ` Masahiro Yamada
2020-07-06 4:48 ` Miguel Ojeda
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to='CAKwvOd=qe5KE1vdUYQmpsW2zmDbk5i-MgRujs9B7wqnAj+af0w@mail.gmail.com' \
--to=ndesaulniers@google.com \
--cc=clang-built-linux@googlegroups.com \
--cc=linux-kbuild@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=masahiroy@kernel.org \
--cc=michal.lkml@markovi.net \
--cc=sam@ravnborg.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.