Commit c690191e authored by Ilya Leoshkevich's avatar Ilya Leoshkevich Committed by Alexei Starovoitov
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s390/bpf: Implement unconditional jump with 32-bit offset 



Implement the cpuv4 unconditional jump with 32-bit offset, which is
encoded as BPF_JMP32 | BPF_JA and stores the offset in the imm field.
Reuse the existing BPF_JMP | BPF_JA logic.

Signed-off-by: default avatarIlya Leoshkevich <iii@linux.ibm.com>
Link: https://lore.kernel.org/r/20230919101336.2223655-8-iii@linux.ibm.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 90f426d3

arch/s390/net/bpf_jit_comp.c

+9 −3
Original line number Diff line number Diff line
@@ -779,6 +779,7 @@ static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp, 
				 int i, bool extra_pass, u32 stack_depth)

{

	struct bpf_insn *insn = &fp->insnsi[i];

	s16 branch_oc_off = insn->off;

	u32 dst_reg = insn->dst_reg;

	u32 src_reg = insn->src_reg;

	int last, insn_count = 1;
@@ -1625,6 +1626,9 @@ static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp, 
	 * instruction itself (loop) and for BPF with offset 0 we

	 * branch to the instruction behind the branch.

	 */

	case BPF_JMP32 | BPF_JA: /* if (true) */

		branch_oc_off = imm;

		fallthrough;

	case BPF_JMP | BPF_JA: /* if (true) */

		mask = 0xf000; /* j */

		goto branch_oc;
@@ -1793,14 +1797,16 @@ static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp, 
		break;

branch_oc:

		if (!is_first_pass(jit) &&

		    can_use_rel(jit, addrs[i + off + 1])) {

		    can_use_rel(jit, addrs[i + branch_oc_off + 1])) {

			/* brc mask,off */

			EMIT4_PCREL_RIC(0xa7040000,

					mask >> 12, addrs[i + off + 1]);

					mask >> 12,

					addrs[i + branch_oc_off + 1]);

		} else {

			/* brcl mask,off */

			EMIT6_PCREL_RILC(0xc0040000,

					 mask >> 12, addrs[i + off + 1]);

					 mask >> 12,

					 addrs[i + branch_oc_off + 1]);

		}

		break;

	}