mainline inclusion
from mainline-v4.20-rc5
commit e2c95a61656d29ceaac97b6a975c8a1f26e26f15
category: bugfix
bugzilla: 5654
CVE: NA

Make fetching of the BPF call address from ppc64 JIT generic. ppc64
was using a slightly different variant rather than through the insns'
imm field encoding as the target address would not fit into that space.
Therefore, the target subprog number was encoded into the insns' offset
and fetched through fp->aux->func[off]->bpf_func instead. Given there
are other JITs with this issue and the mechanism of fetching the address
is JIT-generic, move it into the core as a helper instead. On the JIT
side, we get information on whether the retrieved address is a fixed
one, that is, not changing through JIT passes, or a dynamic one. For
the former, JITs can optimize their imm emission because this doesn't
change jump offsets throughout JIT process.
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Reviewed-by: NSandipan Das <sandipan@linux.ibm.com>
Tested-by: NSandipan Das <sandipan@linux.ibm.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Signed-off-by: NXuefeng Wang <wxf.wang@hisilicon.com>
Reviewed-by: NHanjun Guo <guohanjun@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>