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Commit df3eed3d authored by Michael Holzheu's avatar Michael Holzheu Committed by Martin Schwidefsky
Browse files

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: default avatarMichael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent fbc89c95

arch/s390/net/bpf_jit_comp.c

+2 −2
Original line number Original line Diff line number Diff line
@@ -431,8 +431,8 @@ static int bpf_jit_insn(struct bpf_jit *jit, struct sock_filter *filter, 
		EMIT4_DISP(0x88500000, K);

		EMIT4_DISP(0x88500000, K);

		break;

		break;

	case BPF_ALU | BPF_NEG: /* A = -A */

	case BPF_ALU | BPF_NEG: /* A = -A */

		/* lnr %r5,%r5 */

		/* lcr %r5,%r5 */

		EMIT2(0x1155);

		EMIT2(0x1355);

		break;

		break;

	case BPF_JMP | BPF_JA: /* ip += K */

	case BPF_JMP | BPF_JA: /* ip += K */

		offset = addrs[i + K] + jit->start - jit->prg;

		offset = addrs[i + K] + jit->start - jit->prg;