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bpfilter: check compiler capability in Kconfig

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With the brand-new syntax extension of Kconfig, we can directly
check the compiler capability in the configuration phase.

If the cc-can-link.sh fails, the BPFILTER_UMH is automatically
hidden by the dependency.

I also deleted 'default n', which is no-op.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Masahiro Yamada 2018-06-26 12:55:35 +09:00 committed by David S. Miller
parent 82be2ab159
commit 88e85a7daf
4 changed files with 2 additions and 11 deletions
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5
Makefile
View File

@ -507,11 +507,6 @@ ifeq ($(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-goto.sh $(CC) $(KBUILD_CFLA
KBUILD_AFLAGS += -DCC_HAVE_ASM_GOTO
endif
ifeq ($(shell $(CONFIG_SHELL) $(srctree)/scripts/cc-can-link.sh $(CC)), y)
CC_CAN_LINK := y
export CC_CAN_LINK
endif
# The expansion should be delayed until arch/$(SRCARCH)/Makefile is included.
# Some architectures define CROSS_COMPILE in arch/$(SRCARCH)/Makefile.
# CC_VERSION_TEXT is referenced from Kconfig (so it needs export),

4
net/Makefile
View File

@ -20,11 +20,7 @@ obj-$(CONFIG_TLS) += tls/
obj-$(CONFIG_XFRM) += xfrm/
obj-$(CONFIG_UNIX) += unix/
obj-$(CONFIG_NET) += ipv6/
ifneq ($(CC_CAN_LINK),y)
$(warning CC cannot link executables. Skipping bpfilter.)
else
obj-$(CONFIG_BPFILTER) += bpfilter/
endif
obj-$(CONFIG_PACKET) += packet/
obj-$(CONFIG_NET_KEY) += key/
obj-$(CONFIG_BRIDGE) += bridge/

2
net/bpfilter/Kconfig
View File

@ -1,6 +1,5 @@
menuconfig BPFILTER
bool "BPF based packet filtering framework (BPFILTER)"
default n
depends on NET && BPF && INET
help
This builds experimental bpfilter framework that is aiming to
@ -9,6 +8,7 @@ menuconfig BPFILTER
if BPFILTER
config BPFILTER_UMH
tristate "bpfilter kernel module with user mode helper"
depends on $(success,$(srctree)/scripts/cc-can-link.sh $(CC))
default m
help
This builds bpfilter kernel module with embedded user mode helper

2
scripts/cc-can-link.sh
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@ -1,7 +1,7 @@
#!/bin/sh
# SPDX-License-Identifier: GPL-2.0
cat << "END" | $@ -x c - -o /dev/null >/dev/null 2>&1 && echo "y"
cat << "END" | $@ -x c - -o /dev/null >/dev/null 2>&1
#include <stdio.h>
int main(void)
{