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author | Daniel Borkmann <daniel@iogearbox.net> | 2019-11-24 03:39:42 +0300 |
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committer | Alexei Starovoitov <ast@kernel.org> | 2019-11-25 04:12:11 +0300 |
commit | b553a6ec570044fc1ae300c6fb24f9ce204c5894 (patch) | |
tree | 6121de7c1e38050fd9d4d46480ae6fddf9d585b2 /kernel/bpf/arraymap.c | |
parent | f9a7cf6eb17cd0110c8c47d9e7969fc2716e5772 (diff) | |
download | linux-b553a6ec570044fc1ae300c6fb24f9ce204c5894.tar.xz |
bpf: Simplify __bpf_arch_text_poke poke type handling
Given that we have BPF_MOD_NOP_TO_{CALL,JUMP}, BPF_MOD_{CALL,JUMP}_TO_NOP
and BPF_MOD_{CALL,JUMP}_TO_{CALL,JUMP} poke types and that we also pass in
old_addr as well as new_addr, it's a bit redundant and unnecessarily
complicates __bpf_arch_text_poke() itself since we can derive the same from
the *_addr that were passed in. Hence simplify and use BPF_MOD_{CALL,JUMP}
as types which also allows to clean up call-sites.
In addition to that, __bpf_arch_text_poke() currently verifies that text
matches expected old_insn before we invoke text_poke_bp(). Also add a check
on new_insn and skip rewrite if it already matches. Reason why this is rather
useful is that it avoids making any special casing in prog_array_map_poke_run()
when old and new prog were NULL and has the benefit that also for this case
we perform a check on text whether it really matches our expectations.
Suggested-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/fcb00a2b0b288d6c73de4ef58116a821c8fe8f2f.1574555798.git.daniel@iogearbox.net
Diffstat (limited to 'kernel/bpf/arraymap.c')
-rw-r--r-- | kernel/bpf/arraymap.c | 12 |
1 files changed, 1 insertions, 11 deletions
diff --git a/kernel/bpf/arraymap.c b/kernel/bpf/arraymap.c index 58bdf5fd24cc..f0d19bbb9211 100644 --- a/kernel/bpf/arraymap.c +++ b/kernel/bpf/arraymap.c @@ -746,19 +746,9 @@ static void prog_array_map_poke_run(struct bpf_map *map, u32 key, struct bpf_prog *old, struct bpf_prog *new) { - enum bpf_text_poke_type type; struct prog_poke_elem *elem; struct bpf_array_aux *aux; - if (!old && new) - type = BPF_MOD_NOP_TO_JUMP; - else if (old && !new) - type = BPF_MOD_JUMP_TO_NOP; - else if (old && new) - type = BPF_MOD_JUMP_TO_JUMP; - else - return; - aux = container_of(map, struct bpf_array, map)->aux; WARN_ON_ONCE(!mutex_is_locked(&aux->poke_mutex)); @@ -806,7 +796,7 @@ static void prog_array_map_poke_run(struct bpf_map *map, u32 key, poke->tail_call.key != key) continue; - ret = bpf_arch_text_poke(poke->ip, type, + ret = bpf_arch_text_poke(poke->ip, BPF_MOD_JUMP, old ? (u8 *)old->bpf_func + poke->adj_off : NULL, new ? (u8 *)new->bpf_func + |