bpf, arm64: remove obsolete exception handling from div/mod

Since we've changed div/mod exception handling for src_reg in
eBPF verifier itself, remove the leftovers from arm64 JIT.

Signed-off-by: Daniel Borkmann <[email protected]>
Acked-by: Alexei Starovoitov <[email protected]>
Signed-off-by: Alexei Starovoitov <[email protected]>

Author: borkmann

arch/arm64/net/bpf_jit_comp.c

@@ -390,18 +390,6 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx)
 	case BPF_ALU64 | BPF_DIV | BPF_X:
 	case BPF_ALU | BPF_MOD | BPF_X:
 	case BPF_ALU64 | BPF_MOD | BPF_X:
-	{
-		const u8 r0 = bpf2a64[BPF_REG_0];
-
-		/* if (src == 0) return 0 */
-		jmp_offset = 3; /* skip ahead to else path */
-		check_imm19(jmp_offset);
-		emit(A64_CBNZ(is64, src, jmp_offset), ctx);
-		emit(A64_MOVZ(1, r0, 0, 0), ctx);
-		jmp_offset = epilogue_offset(ctx);
-		check_imm26(jmp_offset);
-		emit(A64_B(jmp_offset), ctx);
-		/* else */
 		switch (BPF_OP(code)) {
 		case BPF_DIV:
 			emit(A64_UDIV(is64, dst, dst, src), ctx);
@@ -413,7 +401,6 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx)
 			break;
 		}
 		break;
-	}
 	case BPF_ALU | BPF_LSH | BPF_X:
 	case BPF_ALU64 | BPF_LSH | BPF_X:
 		emit(A64_LSLV(is64, dst, dst, src), ctx);