Re: [PATCH bpf-next 10/13] bpf, mips64: remove obsolete exception handling from div/mod

[David Daney]

On 01/26/2018 02:33 PM, Daniel Borkmann wrote:

Since we've changed div/mod exception handling for src_reg in
eBPF verifier itself, remove the leftovers from mips64 JIT.

Signed-off-by: Daniel Borkmann <dan...@iogearbox.net>
Cc: David Daney <david.da...@cavium.com>

I didn't test it, but this looks correct, so ...

Reviewed-by: David Daney <david.da...@cavium.com>

---
  arch/mips/net/ebpf_jit.c | 10 ----------
  1 file changed, 10 deletions(-)

diff --git a/arch/mips/net/ebpf_jit.c b/arch/mips/net/ebpf_jit.c
index 4e34703..296f1410 100644
--- a/arch/mips/net/ebpf_jit.c
+++ b/arch/mips/net/ebpf_jit.c
@@ -860,11 +860,6 @@ static int build_one_insn(const struct bpf_insn *insn, 
struct jit_ctx *ctx,
                        break;
                case BPF_DIV:
                case BPF_MOD:
-                       b_off = b_imm(exit_idx, ctx);
-                       if (is_bad_offset(b_off))
-                               return -E2BIG;
-                       emit_instr(ctx, beq, src, MIPS_R_ZERO, b_off);
-                       emit_instr(ctx, movz, MIPS_R_V0, MIPS_R_ZERO, src);
                        emit_instr(ctx, ddivu, dst, src);
                        if (bpf_op == BPF_DIV)
                                emit_instr(ctx, mflo, dst);
@@ -943,11 +938,6 @@ static int build_one_insn(const struct bpf_insn *insn, 
struct jit_ctx *ctx,
                        break;
                case BPF_DIV:
                case BPF_MOD:
-                       b_off = b_imm(exit_idx, ctx);
-                       if (is_bad_offset(b_off))
-                               return -E2BIG;
-                       emit_instr(ctx, beq, src, MIPS_R_ZERO, b_off);
-                       emit_instr(ctx, movz, MIPS_R_V0, MIPS_R_ZERO, src);
                        emit_instr(ctx, divu, dst, src);
                        if (bpf_op == BPF_DIV)
                                emit_instr(ctx, mflo, dst);