s390/bpf: Fix ALU_NEG (A = -A)

Currently the LOAD NEGATIVE (lnr) instruction is used for ALU_NEG. This instruction always loads the negative value. Therefore, if A is already negative, it remains unchanged. To fix this use LOAD COMPLEMENT (lcr) instead. Signed-off-by: Michael Holzheu <[email protected]> Signed-off-by: Martin Schwidefsky <[email protected]>
ambv · Jan 9, 2015 · df3eed3 · df3eed3
1 parent fbc89c9
commit df3eed3
Showing 1 changed file with 2 additions and 2 deletions.
diff --git a/arch/s390/net/bpf_jit_comp.c b/arch/s390/net/bpf_jit_comp.c
@@ -431,8 +431,8 @@ static int bpf_jit_insn(struct bpf_jit *jit, struct sock_filter *filter,
 		EMIT4_DISP(0x88500000, K);
 		break;
 	case BPF_ALU | BPF_NEG: /* A = -A */
-		/* lnr %r5,%r5 */
-		EMIT2(0x1155);
+		/* lcr %r5,%r5 */
+		EMIT2(0x1355);
 		break;
 	case BPF_JMP | BPF_JA: /* ip += K */
 		offset = addrs[i + K] + jit->start - jit->prg;