bpf: provide helper that indicates eBPF was migrated

During recent discussions we had with Michael, we found that it would
be useful to have an indicator that tells the JIT that an eBPF program
had been migrated from classic instructions into eBPF instructions, as
only in that case A and X need to be cleared in the prologue. Such eBPF
programs do not set a particular type, but all have BPF_PROG_TYPE_UNSPEC.
Thus, introduce a small helper for cde66c2d88 ("s390/bpf: Only clear
A and X for converted BPF programs") and possibly others in future.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Daniel Borkmann
2015-07-30 12:42:47 +02:00
committed by David S. Miller
parent 4962fa10f3
commit 7b36f92934
2 changed files with 11 additions and 1 deletions

View File

@@ -1245,7 +1245,7 @@ static int bpf_jit_prog(struct bpf_jit *jit, struct bpf_prog *fp)
jit->lit = jit->lit_start;
jit->prg = 0;
bpf_jit_prologue(jit, fp->type == BPF_PROG_TYPE_UNSPEC);
bpf_jit_prologue(jit, bpf_prog_was_classic(fp));
for (i = 0; i < fp->len; i += insn_count) {
insn_count = bpf_jit_insn(jit, fp, i);
if (insn_count < 0)