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authorAlexei Starovoitov <ast@kernel.org>2020-08-18 21:27:58 -0700
committerDaniel Borkmann <daniel@iogearbox.net>2020-08-20 16:02:36 +0200
commitd71fa5c9763c24dd997a2fa4feb7a13a95bab42c (patch)
treecc0059ab68f8884169ba1176acd05da5148c83ad /init/Kconfig
parentf0fdfefb2d4da5b76c3f810be0edb2ab90360224 (diff)
downloadlinux-d71fa5c9763c24dd997a2fa4feb7a13a95bab42c.tar.gz
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 <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200819042759.51280-4-alexei.starovoitov@gmail.com
Diffstat (limited to 'init/Kconfig')
-rw-r--r--init/Kconfig2
1 files changed, 2 insertions, 0 deletions
diff --git a/init/Kconfig b/init/Kconfig
index d6a0b31b13dc..fc10f7ede5f6 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1710,6 +1710,8 @@ config BPF_JIT_DEFAULT_ON
 	def_bool ARCH_WANT_DEFAULT_BPF_JIT || BPF_JIT_ALWAYS_ON
 	depends on HAVE_EBPF_JIT && BPF_JIT
 
+source "kernel/bpf/preload/Kconfig"
+
 config USERFAULTFD
 	bool "Enable userfaultfd() system call"
 	depends on MMU