Commit aea7ef8a authored by Hari Bathini's avatar Hari Bathini Committed by Michael Ellerman
Browse files

powerpc/bpf/32: add support for BPF_ATOMIC bitwise operations 



Adding instructions for ppc32 for

atomic_and
atomic_or
atomic_xor
atomic_fetch_add
atomic_fetch_and
atomic_fetch_or
atomic_fetch_xor

Signed-off-by: default avatarHari Bathini <hbathini@linux.ibm.com>
Tested-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> (ppc64le)
Reviewed-by: default avatarNaveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220610155552.25892-5-hbathini@linux.ibm.com
parent 1e82dfaa

arch/powerpc/net/bpf_jit_comp32.c

+41 −12
Original line number Diff line number Diff line
@@ -294,6 +294,7 @@ int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, struct codegen_context * 
		u32 dst_reg_h = dst_reg - 1;

		u32 src_reg = bpf_to_ppc(insn[i].src_reg);

		u32 src_reg_h = src_reg - 1;

		u32 ax_reg = bpf_to_ppc(BPF_REG_AX);

		u32 tmp_reg = bpf_to_ppc(TMP_REG);

		u32 size = BPF_SIZE(code);

		s16 off = insn[i].off;
@@ -798,25 +799,53 @@ int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, struct codegen_context * 
		 * BPF_STX ATOMIC (atomic ops)

		 */

		case BPF_STX | BPF_ATOMIC | BPF_W:

			if (imm != BPF_ADD) {

				pr_err_ratelimited("eBPF filter atomic op code %02x (@%d) unsupported\n",

						   code, i);

				return -ENOTSUPP;

			}



			/* *(u32 *)(dst + off) += src */



			bpf_set_seen_register(ctx, tmp_reg);

			bpf_set_seen_register(ctx, ax_reg);



			/* Get offset into TMP_REG */

			EMIT(PPC_RAW_LI(tmp_reg, off));

			tmp_idx = ctx->idx * 4;

			/* load value from memory into r0 */

			EMIT(PPC_RAW_LWARX(_R0, tmp_reg, dst_reg, 0));

			/* add value from src_reg into this */



			/* Save old value in BPF_REG_AX */

			if (imm & BPF_FETCH)

				EMIT(PPC_RAW_MR(ax_reg, _R0));



			switch (imm) {

			case BPF_ADD:

			case BPF_ADD | BPF_FETCH:

				EMIT(PPC_RAW_ADD(_R0, _R0, src_reg));

			/* store result back */

				break;

			case BPF_AND:

			case BPF_AND | BPF_FETCH:

				EMIT(PPC_RAW_AND(_R0, _R0, src_reg));

				break;

			case BPF_OR:

			case BPF_OR | BPF_FETCH:

				EMIT(PPC_RAW_OR(_R0, _R0, src_reg));

				break;

			case BPF_XOR:

			case BPF_XOR | BPF_FETCH:

				EMIT(PPC_RAW_XOR(_R0, _R0, src_reg));

				break;

			default:

				pr_err_ratelimited("eBPF filter atomic op code %02x (@%d) unsupported\n",

						   code, i);

				return -EOPNOTSUPP;

			}



			/* store new value */

			EMIT(PPC_RAW_STWCX(_R0, tmp_reg, dst_reg));

			/* we're done if this succeeded */

			PPC_BCC_SHORT(COND_NE, (ctx->idx - 3) * 4);

			PPC_BCC_SHORT(COND_NE, tmp_idx);



			/* For the BPF_FETCH variant, get old data into src_reg */

			if (imm & BPF_FETCH) {

				EMIT(PPC_RAW_MR(src_reg, ax_reg));

				if (!fp->aux->verifier_zext)

					EMIT(PPC_RAW_LI(src_reg_h, 0));

			}

			break;



		case BPF_STX | BPF_ATOMIC | BPF_DW: /* *(u64 *)(dst + off) += src */