Commit 3de55893 authored by Ilya Leoshkevich's avatar Ilya Leoshkevich Committed by Alexei Starovoitov
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s390/bpf: Implement BPF_MOV | BPF_X with sign-extension 



Implement the cpuv4 register-to-register move with sign extension. It
is distinguished from the normal moves by non-zero values in
insn->off, which determine the source size. s390x has instructions to
deal with all of them: lbr, lhr, lgbr, lghr and lgfr.

Signed-off-by: default avatarIlya Leoshkevich <iii@linux.ibm.com>
Link: https://lore.kernel.org/r/20230919101336.2223655-5-iii@linux.ibm.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 9873ce2e

arch/s390/net/bpf_jit_comp.c

+40 −8
Original line number Diff line number Diff line
@@ -795,16 +795,48 @@ static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp, 
	/*

	 * BPF_MOV

	 */

	case BPF_ALU | BPF_MOV | BPF_X: /* dst = (u32) src */

	case BPF_ALU | BPF_MOV | BPF_X:

		switch (insn->off) {

		case 0: /* DST = (u32) SRC */

			/* llgfr %dst,%src */

			EMIT4(0xb9160000, dst_reg, src_reg);

			if (insn_is_zext(&insn[1]))

				insn_count = 2;

			break;

	case BPF_ALU64 | BPF_MOV | BPF_X: /* dst = src */

		case 8: /* DST = (u32)(s8) SRC */

			/* lbr %dst,%src */

			EMIT4(0xb9260000, dst_reg, src_reg);

			/* llgfr %dst,%dst */

			EMIT4(0xb9160000, dst_reg, dst_reg);

			break;

		case 16: /* DST = (u32)(s16) SRC */

			/* lhr %dst,%src */

			EMIT4(0xb9270000, dst_reg, src_reg);

			/* llgfr %dst,%dst */

			EMIT4(0xb9160000, dst_reg, dst_reg);

			break;

		}

		break;

	case BPF_ALU64 | BPF_MOV | BPF_X:

		switch (insn->off) {

		case 0: /* DST = SRC */

			/* lgr %dst,%src */

			EMIT4(0xb9040000, dst_reg, src_reg);

			break;

		case 8: /* DST = (s8) SRC */

			/* lgbr %dst,%src */

			EMIT4(0xb9060000, dst_reg, src_reg);

			break;

		case 16: /* DST = (s16) SRC */

			/* lghr %dst,%src */

			EMIT4(0xb9070000, dst_reg, src_reg);

			break;

		case 32: /* DST = (s32) SRC */

			/* lgfr %dst,%src */

			EMIT4(0xb9140000, dst_reg, src_reg);

			break;

		}

		break;

	case BPF_ALU | BPF_MOV | BPF_K: /* dst = (u32) imm */

		/* llilf %dst,imm */

		EMIT6_IMM(0xc00f0000, dst_reg, imm);