s390/bpf: Implement unconditional jump with 32-bit offset

Implement the cpuv4 unconditional jump with 32-bit offset, which is encoded as BPF_JMP32 | BPF_JA and stores the offset in the imm field. Reuse the existing BPF_JMP | BPF_JA logic. Signed-off-by: Ilya Leoshkevich <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Alexei Starovoitov <[email protected]>
torvalds · Sep 21, 2023 · c690191 · c690191
1 parent 90f426d
commit c690191
Showing 1 changed file with 9 additions and 3 deletions.
diff --git a/arch/s390/net/bpf_jit_comp.c b/arch/s390/net/bpf_jit_comp.c
@@ -779,6 +779,7 @@ static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp,
  int i, bool extra_pass, u32 stack_depth)
 {
  struct bpf_insn *insn = &fp->insnsi[i];
+ s16 branch_oc_off = insn->off;
  u32 dst_reg = insn->dst_reg;
  u32 src_reg = insn->src_reg;
  int last, insn_count = 1;
@@ -1625,6 +1626,9 @@ static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp,
  * instruction itself (loop) and for BPF with offset 0 we
  * branch to the instruction behind the branch.
  */
+ case BPF_JMP32 | BPF_JA: /* if (true) */
+ branch_oc_off = imm;
+ fallthrough;
  case BPF_JMP | BPF_JA: /* if (true) */
  mask = 0xf000; /* j */
  goto branch_oc;
@@ -1793,14 +1797,16 @@ static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp,
  break;
 branch_oc:
  if (!is_first_pass(jit) &&
- can_use_rel(jit, addrs[i + off + 1])) {
+ can_use_rel(jit, addrs[i + branch_oc_off + 1])) {
  /* brc mask,off */
  EMIT4_PCREL_RIC(0xa7040000,
- mask >> 12, addrs[i + off + 1]);
+ mask >> 12,
+ addrs[i + branch_oc_off + 1]);
  } else {
  /* brcl mask,off */
  EMIT6_PCREL_RILC(0xc0040000,
- mask >> 12, addrs[i + off + 1]);
+ mask >> 12,
+ addrs[i + branch_oc_off + 1]);
  }
  break;
  }