2021-01-12 19:04:08

by Alistair Delva

[permalink] [raw]
Subject: [PATCH] kbuild: improve libelf detection

When `pkg-config --libs' wasn't used or didn't return anything useful,
the test for libelf would fail even if the headers and libraries were
available to kbuild via KBUILD_HOSTCFLAGS and KBUILD_HOSTLDFLAGS.

This makes the check in the core Makefile match the check that is done
in tools/objtool/Makefile. Specifically, the C compiler is passed the
full KBUILD_HOSTCFLAGS and KBUILD_HOSTLDFLAGS, which may have set up
additional sysroot/include/library search paths to find libelf.

Cc: [email protected]
Cc: [email protected]
Cc: Masahiro Yamada <[email protected]>
Cc: Rolf Eike Beer <[email protected]>
Signed-off-by: Alistair Delva <[email protected]>
---
Makefile | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/Makefile b/Makefile
index 9e73f82e0d86..3269e155fbe4 100644
--- a/Makefile
+++ b/Makefile
@@ -1074,8 +1074,9 @@ export mod_sign_cmd

HOST_LIBELF_LIBS = $(shell pkg-config libelf --libs 2>/dev/null || echo -lelf)

-has_libelf = $(call try-run,\
- echo "int main() {}" | $(HOSTCC) -xc -o /dev/null $(HOST_LIBELF_LIBS) -,1,0)
+has_libelf := $(call try-run,\
+ echo "int main() {}" | \
+ $(HOSTCC) $(KBUILD_HOSTCFLAGS) -xc -o /dev/null $(KBUILD_HOSTLDFLAGS) $(HOST_LIBELF_LIBS) -,1,0)

ifdef CONFIG_STACK_VALIDATION
ifeq ($(has_libelf),1)
--
2.29.2


2021-01-13 12:42:10

by Rolf Eike Beer

[permalink] [raw]
Subject: Re: [PATCH] kbuild: improve libelf detection

Am Dienstag, 12. Januar 2021, 20:00:10 CET schrieb Alistair Delva:
> When `pkg-config --libs' wasn't used or didn't return anything useful,
> the test for libelf would fail even if the headers and libraries were
> available to kbuild via KBUILD_HOSTCFLAGS and KBUILD_HOSTLDFLAGS.
>
> This makes the check in the core Makefile match the check that is done
> in tools/objtool/Makefile. Specifically, the C compiler is passed the
> full KBUILD_HOSTCFLAGS and KBUILD_HOSTLDFLAGS, which may have set up
> additional sysroot/include/library search paths to find libelf.

Sounds plausible.

--
Rolf Eike Beer, emlix GmbH, http://www.emlix.com
Fon +49 551 30664-0, Fax +49 551 30664-11
Gothaer Platz 3, 37083 Göttingen, Germany
Sitz der Gesellschaft: Göttingen, Amtsgericht Göttingen HR B 3160
Geschäftsführung: Heike Jordan, Dr. Uwe Kracke – Ust-IdNr.: DE 205 198 055

emlix - smart embedded open source


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