From: Masahiro Yamada <masahiroy@kernel.org>
To: Alexei Starovoitov <ast@kernel.org>,
netdev@vger.kernel.org, bpf@vger.kernel.org
Cc: linux-kbuild@vger.kernel.org, "Michal Kubecek" <mkubecek@suse.cz>,
linux-kernel@vger.kernel.org,
"Masahiro Yamada" <masahiroy@kernel.org>,
"Andrii Nakryiko" <andriin@fb.com>,
"Daniel Borkmann" <daniel@iogearbox.net>,
"David S. Miller" <davem@davemloft.net>,
"Jakub Kicinski" <kuba@kernel.org>,
"John Fastabend" <john.fastabend@gmail.com>,
"KP Singh" <kpsingh@chromium.org>,
"Martin KaFai Lau" <kafai@fb.com>,
"Sam Ravnborg" <sam@ravnborg.org>,
"Song Liu" <songliubraving@fb.com>,
"Valdis Kl ē tnieks" <valdis.kletnieks@vt.edu>,
"Yonghong Song" <yhs@fb.com>
Subject: [PATCH] bpfilter: allow to build bpfilter_umh as a module without static library
Date: Wed, 1 Jul 2020 18:26:44 +0900 [thread overview]
Message-ID: <20200701092644.762234-1-masahiroy@kernel.org> (raw)
Originally, bpfilter_umh was linked with -static only when
CONFIG_BPFILTER_UMH=y.
Commit 8a2cc0505cc4 ("bpfilter: use 'userprogs' syntax to build
bpfilter_umh") silently, accidentally dropped the CONFIG_BPFILTER_UMH=y
test in the Makefile. Revive it in order to link it dynamically when
CONFIG_BPFILTER_UMH=m.
Since commit b1183b6dca3e ("bpfilter: check if $(CC) can link static
libc in Kconfig"), the compiler must be capable of static linking to
enable CONFIG_BPFILTER_UMH, but it requires more than needed.
To loosen the compiler requirement, I changed the dependency as follows:
depends on CC_CAN_LINK
depends on m || CC_CAN_LINK_STATIC
If CONFIG_CC_CAN_LINK_STATIC in unset, CONFIG_BPFILTER_UMH is restricted
to 'm' or 'n'.
In theory, CONFIG_CC_CAN_LINK is not required for CONFIG_BPFILTER_UMH=y,
but I did not come up with a good way to describe it.
Fixes: 8a2cc0505cc4 ("bpfilter: use 'userprogs' syntax to build bpfilter_umh")
Reported-by: Michal Kubecek <mkubecek@suse.cz>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
---
net/bpfilter/Kconfig | 10 ++++++----
net/bpfilter/Makefile | 2 ++
2 files changed, 8 insertions(+), 4 deletions(-)
diff --git a/net/bpfilter/Kconfig b/net/bpfilter/Kconfig
index 84015ef3ee27..73d0b12789f1 100644
--- a/net/bpfilter/Kconfig
+++ b/net/bpfilter/Kconfig
@@ -9,12 +9,14 @@ menuconfig BPFILTER
if BPFILTER
config BPFILTER_UMH
tristate "bpfilter kernel module with user mode helper"
- depends on CC_CAN_LINK_STATIC
+ depends on CC_CAN_LINK
+ depends on m || CC_CAN_LINK_STATIC
default m
help
This builds bpfilter kernel module with embedded user mode helper
- Note: your toolchain must support building static binaries, since
- rootfs isn't mounted at the time when __init functions are called
- and do_execv won't be able to find the elf interpreter.
+ Note: To compile this as built-in, your toolchain must support
+ building static binaries, since rootfs isn't mounted at the time
+ when __init functions are called and do_execv won't be able to find
+ the elf interpreter.
endif
diff --git a/net/bpfilter/Makefile b/net/bpfilter/Makefile
index f23b53294fba..cdac82b8c53a 100644
--- a/net/bpfilter/Makefile
+++ b/net/bpfilter/Makefile
@@ -7,10 +7,12 @@ userprogs := bpfilter_umh
bpfilter_umh-objs := main.o
userccflags += -I $(srctree)/tools/include/ -I $(srctree)/tools/include/uapi
+ifeq ($(CONFIG_BPFILTER_UMH), y)
# builtin bpfilter_umh should be linked with -static
# since rootfs isn't mounted at the time of __init
# function is called and do_execv won't find elf interpreter
userldflags += -static
+endif
$(obj)/bpfilter_umh_blob.o: $(obj)/bpfilter_umh
--
2.25.1
next reply other threads:[~2020-07-01 9:29 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-01 9:26 Masahiro Yamada [this message]
2020-07-01 12:57 ` [PATCH] bpfilter: allow to build bpfilter_umh as a module without static library Michal Kubecek
2020-07-01 17:46 ` Alexei Starovoitov
2020-07-01 17:50 ` Masahiro Yamada
2020-07-14 19:39 ` Alexei Starovoitov
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=20200701092644.762234-1-masahiroy@kernel.org \
--to=masahiroy@kernel.org \
--cc=andriin@fb.com \
--cc=ast@kernel.org \
--cc=bpf@vger.kernel.org \
--cc=daniel@iogearbox.net \
--cc=davem@davemloft.net \
--cc=john.fastabend@gmail.com \
--cc=kafai@fb.com \
--cc=kpsingh@chromium.org \
--cc=kuba@kernel.org \
--cc=linux-kbuild@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mkubecek@suse.cz \
--cc=netdev@vger.kernel.org \
--cc=sam@ravnborg.org \
--cc=songliubraving@fb.com \
--cc=valdis.kletnieks@vt.edu \
--cc=yhs@fb.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.