diff options
| author | Ilya Leoshkevich <iii@linux.ibm.com> | 2020-07-17 19:53:24 +0300 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2020-07-21 23:26:25 +0300 |
| commit | 5fa6974471c5518a50bdd814067508dbcb477251 (patch) | |
| tree | fffc3137156ad321370641684a593de6532dcf9c | |
| parent | 7477d43be5b1448bc0d4c85cb185a0144cc080e1 (diff) | |
| download | linux-5fa6974471c5518a50bdd814067508dbcb477251.tar.xz | |
s390/bpf: Use brcl for jumping to exit_ip if necessary
"BPF_MAXINSNS: Maximum possible literals" test causes panic with
bpf_jit_harden = 2. The reason is that BPF_JMP | BPF_EXIT is always
emitted as brc, however, after removal of JITed image size
limitations, brcl might be required.
Fix by using brcl when necessary.
Fixes: 4e9b4a6883dd ("s390/bpf: Use relative long branches")
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200717165326.6786-4-iii@linux.ibm.com
| -rw-r--r-- | arch/s390/net/bpf_jit_comp.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/arch/s390/net/bpf_jit_comp.c b/arch/s390/net/bpf_jit_comp.c index 6b3d612948fb..6b8968f6e207 100644 --- a/arch/s390/net/bpf_jit_comp.c +++ b/arch/s390/net/bpf_jit_comp.c @@ -1268,8 +1268,12 @@ static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp, last = (i == fp->len - 1) ? 1 : 0; if (last) break; - /* j <exit> */ - EMIT4_PCREL(0xa7f40000, jit->exit_ip - jit->prg); + if (!is_first_pass(jit) && can_use_rel(jit, jit->exit_ip)) + /* brc 0xf, <exit> */ + EMIT4_PCREL_RIC(0xa7040000, 0xf, jit->exit_ip); + else + /* brcl 0xf, <exit> */ + EMIT6_PCREL_RILC(0xc0040000, 0xf, jit->exit_ip); break; /* * Branch relative (number of skipped instructions) to offset on |