mips: bpf: Fix broken BPF_MOD

commit 2e46477a upstream.

Remove optimize_div() from BPF_MOD | BPF_K case
since we don't know the dividend and fix the
emit_mod() by reading the mod operation result from HI register
Signed-off-by: Denis Kirjanov <kda@linux-powerpc.org>
Reviewed-by: Markos Chandras <markos.chandras@imgtec.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

arch/mips/net/bpf_jit.c

@@ -430,7 +430,7 @@ static inline void emit_mod(unsigned int dst, unsigned int src,
 		u32 *p = &ctx->target[ctx->idx];
 		uasm_i_divu(&p, dst, src);
 		p = &ctx->target[ctx->idx + 1];
-		uasm_i_mflo(&p, dst);
+		uasm_i_mfhi(&p, dst);
 	}
 	ctx->idx += 2; /* 2 insts */
 }
@@ -1005,7 +1005,7 @@ static int build_body(struct jit_ctx *ctx)
 			break;
 		case BPF_ALU | BPF_MOD | BPF_K:
 			/* A %= k */
-			if (k == 1 || optimize_div(&k)) {
+			if (k == 1) {
 				ctx->flags |= SEEN_A;
 				emit_jit_reg_move(r_A, r_zero, ctx);
 			} else {