Messages in this thread | | | From | Masahiro Yamada <> | Date | Sun, 10 Jun 2018 00:13:43 +0900 | Subject | Re: [PATCH 3/3] bpfilter: do not (ab)use host-program build rule |
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2018-06-09 5:52 GMT+09:00 Alexei Starovoitov <alexei.starovoitov@gmail.com>: > On Sat, Jun 09, 2018 at 02:12:10AM +0900, Masahiro Yamada wrote: >> It is an ugly hack to overwrite $(HOSTCC) with $(CC) to reuse the >> build rules from scripts/Makefile.host. It should not be tedious >> to write a build rule for its own. >> >> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> >> --- >> >> net/bpfilter/Makefile | 17 +++++++++++------ >> net/bpfilter/{main.c => bpfilter_umh.c} | 0 >> 2 files changed, 11 insertions(+), 6 deletions(-) >> rename net/bpfilter/{main.c => bpfilter_umh.c} (100%) >> >> diff --git a/net/bpfilter/Makefile b/net/bpfilter/Makefile >> index 39c6980..6571b30 100644 >> --- a/net/bpfilter/Makefile >> +++ b/net/bpfilter/Makefile >> @@ -3,18 +3,23 @@ >> # Makefile for the Linux BPFILTER layer. >> # >> >> -hostprogs-y := bpfilter_umh >> -bpfilter_umh-objs := main.o >> -HOSTCFLAGS += -I. -Itools/include/ -Itools/include/uapi >> -HOSTCC := $(CC) > > that is a hack indeed. I don't like it either, but see below. > >> - >> ifeq ($(CONFIG_BPFILTER_UMH), y) >> # builtin bpfilter_umh should be compiled with -static >> # since rootfs isn't mounted at the time of __init >> # function is called and do_execv won't find elf interpreter >> -HOSTLDFLAGS += -static >> +STATIC := -static >> endif >> >> +quiet_cmd_cc_user = CC $@ >> + cmd_cc_user = $(CC) -Wall -Wmissing-prototypes -O2 -std=gnu89 \ >> + -I$(srctree) -I$(srctree)/tools/include/ \ >> + -I$(srctree)/tools/include/uapi $(STATIC) -o $@ $< >> + >> +$(obj)/bpfilter_umh: $(src)/bpfilter_umh.c FORCE >> + $(call if_changed,cc_user) > > Does this scale? > Please see two top patches here: > https://git.kernel.org/pub/scm/linux/kernel/git/ast/bpf.git/log/?h=ipt_bpf > that add more meat to bpfilter and a lot more files.
Oh, I just thought main.c was the only user-program file.
> Recompiling all of them at once isn't nice either.
Indeed.
It should be able to compile .c -> .o separately.
> This Makefile needs different .c -> .o rules for bpfilter_kern.c files > that get compiled into kernel module and for the rest of umh files: > main.c ctor.c init.c gen.c etc > that need to be compiled .c -> .o differently. > I don't see how to do it without ugly hacks in Makefile. > In that sense HOSTCC = CC hack looked the least ugly to me that's > why I went with it. > Better ideas?
I will think about it after your patches land.
I will drop this for now.
-- Best Regards Masahiro Yamada
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