From: Masahiro Yamada <masahiroy@kernel.org>
To: linux-kbuild@vger.kernel.org
Cc: linux-kernel@vger.kernel.org,
Nathan Chancellor <nathan@kernel.org>,
Nick Desaulniers <ndesaulniers@google.com>,
llvm@lists.linux.dev, Fangrui Song <maskray@google.com>,
Masahiro Yamada <masahiroy@kernel.org>,
"Dmitry V. Levin" <ldv@altlinux.org>,
Elliot Berman <quic_eberman@quicinc.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Subject: [PATCH] kbuild: add --target to correctly cross-compile UAPI headers with Clang
Date: Sat, 5 Mar 2022 18:28:16 +0900 [thread overview]
Message-ID: <20220305092816.92114-1-masahiroy@kernel.org> (raw)
When you compile-test UAPI headers (CONFIG_UAPI_HEADER_TEST=y) with
Clang, they are currently compiled for the host target (likely x86_64)
regardless of the given ARCH=.
As a matter of fact, some exported headers include libc headers.
For example, include/uapi/sound/asound.h includes <stdlib.h> and <time.h>
after being exported. It is better to try to match the header search
paths to the target we are compiling them for.
Pick up the --target triple from KBUILD_CFLAGS in the same ways as
commit 7f58b487e9ff ("kbuild: make Clang build userprogs for target
architecture").
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
---
As far as I tested on Debian, Clang falls back to /usr/include/
when libc dev package for the specified target is not installed.
For example, --target=aarch64-linux-gnu tries to include
/usr/aarch64-linux-gnu/include/stdlib.h
, which is available when libc6-dev-arm64-cross is installed.
Otherwise, includes
/usr/include/stdlib.h
usr/include/Makefile | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/usr/include/Makefile b/usr/include/Makefile
index 703ee034033e..19ac4b63866d 100644
--- a/usr/include/Makefile
+++ b/usr/include/Makefile
@@ -12,7 +12,7 @@ UAPI_CFLAGS += $(CLANG_FLAGS)
# In theory, we do not care -m32 or -m64 for header compile tests.
# It is here just because CONFIG_CC_CAN_LINK is tested with -m32 or -m64.
-UAPI_CFLAGS += $(filter -m32 -m64, $(KBUILD_CFLAGS))
+UAPI_CFLAGS += $(filter -m32 -m64 --target=%, $(KBUILD_CFLAGS))
# USERCFLAGS might contain sysroot location for CC.
UAPI_CFLAGS += $(USERCFLAGS)
--
2.32.0
reply other threads:[~2022-03-05 9:33 UTC|newest]
Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
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=20220305092816.92114-1-masahiroy@kernel.org \
--to=masahiroy@kernel.org \
--cc=gregkh@linuxfoundation.org \
--cc=ldv@altlinux.org \
--cc=linux-kbuild@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=llvm@lists.linux.dev \
--cc=maskray@google.com \
--cc=nathan@kernel.org \
--cc=ndesaulniers@google.com \
--cc=quic_eberman@quicinc.com \
/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.