From d71fa5c9763c24dd997a2fa4feb7a13a95bab42c Mon Sep 17 00:00:00 2001 From: Alexei Starovoitov Date: Tue, 18 Aug 2020 21:27:58 -0700 Subject: bpf: Add kernel module with user mode driver that populates bpffs. Add kernel module with user mode driver that populates bpffs with BPF iterators. $ mount bpffs /my/bpffs/ -t bpf $ ls -la /my/bpffs/ total 4 drwxrwxrwt 2 root root 0 Jul 2 00:27 . drwxr-xr-x 19 root root 4096 Jul 2 00:09 .. -rw------- 1 root root 0 Jul 2 00:27 maps.debug -rw------- 1 root root 0 Jul 2 00:27 progs.debug The user mode driver will load BPF Type Formats, create BPF maps, populate BPF maps, load two BPF programs, attach them to BPF iterators, and finally send two bpf_link IDs back to the kernel. The kernel will pin two bpf_links into newly mounted bpffs instance under names "progs.debug" and "maps.debug". These two files become human readable. $ cat /my/bpffs/progs.debug id name attached 11 dump_bpf_map bpf_iter_bpf_map 12 dump_bpf_prog bpf_iter_bpf_prog 27 test_pkt_access 32 test_main test_pkt_access test_pkt_access 33 test_subprog1 test_pkt_access_subprog1 test_pkt_access 34 test_subprog2 test_pkt_access_subprog2 test_pkt_access 35 test_subprog3 test_pkt_access_subprog3 test_pkt_access 36 new_get_skb_len get_skb_len test_pkt_access 37 new_get_skb_ifindex get_skb_ifindex test_pkt_access 38 new_get_constant get_constant test_pkt_access The BPF program dump_bpf_prog() in iterators.bpf.c is printing this data about all BPF programs currently loaded in the system. This information is unstable and will change from kernel to kernel as ".debug" suffix conveys. Signed-off-by: Alexei Starovoitov Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20200819042759.51280-4-alexei.starovoitov@gmail.com --- kernel/bpf/preload/Makefile | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) create mode 100644 kernel/bpf/preload/Makefile (limited to 'kernel/bpf/preload/Makefile') diff --git a/kernel/bpf/preload/Makefile b/kernel/bpf/preload/Makefile new file mode 100644 index 000000000000..12c7b62b9b6e --- /dev/null +++ b/kernel/bpf/preload/Makefile @@ -0,0 +1,23 @@ +# SPDX-License-Identifier: GPL-2.0 + +LIBBPF_SRCS = $(srctree)/tools/lib/bpf/ +LIBBPF_A = $(obj)/libbpf.a +LIBBPF_OUT = $(abspath $(obj)) + +$(LIBBPF_A): + $(Q)$(MAKE) -C $(LIBBPF_SRCS) OUTPUT=$(LIBBPF_OUT)/ $(LIBBPF_OUT)/libbpf.a + +userccflags += -I $(srctree)/tools/include/ -I $(srctree)/tools/include/uapi \ + -I $(srctree)/tools/lib/ -Wno-unused-result + +userprogs := bpf_preload_umd + +bpf_preload_umd-objs := iterators/iterators.o +bpf_preload_umd-userldlibs := $(LIBBPF_A) -lelf -lz + +$(obj)/bpf_preload_umd: $(LIBBPF_A) + +$(obj)/bpf_preload_umd_blob.o: $(obj)/bpf_preload_umd + +obj-$(CONFIG_BPF_PRELOAD_UMD) += bpf_preload.o +bpf_preload-objs += bpf_preload_kern.o bpf_preload_umd_blob.o -- cgit v1.2.3 From 9d9aae53b96d0659e9085221453e48b7df9edbed Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= Date: Sun, 27 Sep 2020 21:30:05 +0200 Subject: bpf/preload: Make sure Makefile cleans up after itself, and add .gitignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The Makefile in bpf/preload builds a local copy of libbpf, but does not properly clean up after itself. This can lead to subsequent compilation failures, since the feature detection cache is kept around which can lead subsequent detection to fail. Fix this by properly setting clean-files, and while we're at it, also add a .gitignore for the directory to ignore the build artifacts. Fixes: d71fa5c9763c ("bpf: Add kernel module with user mode driver that populates bpffs.") Signed-off-by: Toke Høiland-Jørgensen Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20200927193005.8459-1-toke@redhat.com --- kernel/bpf/preload/Makefile | 2 ++ 1 file changed, 2 insertions(+) (limited to 'kernel/bpf/preload/Makefile') diff --git a/kernel/bpf/preload/Makefile b/kernel/bpf/preload/Makefile index 12c7b62b9b6e..23ee310b6eb4 100644 --- a/kernel/bpf/preload/Makefile +++ b/kernel/bpf/preload/Makefile @@ -12,6 +12,8 @@ userccflags += -I $(srctree)/tools/include/ -I $(srctree)/tools/include/uapi \ userprogs := bpf_preload_umd +clean-files := $(userprogs) bpf_helper_defs.h FEATURE-DUMP.libbpf staticobjs/ feature/ + bpf_preload_umd-objs := iterators/iterators.o bpf_preload_umd-userldlibs := $(LIBBPF_A) -lelf -lz -- cgit v1.2.3