Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 7bdc97be authored by Jakub Kicinski's avatar Jakub Kicinski Committed by Daniel Borkmann
Browse files

nfp: bpf: optimize comparisons to negative constants 



Comparison instruction requires a subtraction.  If the constant
is negative we are more likely to fit it into a NFP instruction
directly if we change the sign and use addition.

Signed-off-by: default avatarJakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
parent 61dd8f00

drivers/net/ethernet/netronome/nfp/bpf/jit.c

+30 −12
Original line number Original line Diff line number Diff line
@@ -1247,6 +1247,7 @@ static int cmp_imm(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta) 
	const struct bpf_insn *insn = &meta->insn;

	const struct bpf_insn *insn = &meta->insn;

	u64 imm = insn->imm; /* sign extend */

	u64 imm = insn->imm; /* sign extend */

	const struct jmp_code_map *code;

	const struct jmp_code_map *code;

	enum alu_op alu_op, carry_op;

	u8 reg = insn->dst_reg * 2;

	u8 reg = insn->dst_reg * 2;

	swreg tmp_reg;

	swreg tmp_reg;
@@ -1254,19 +1255,22 @@ static int cmp_imm(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta) 
	if (!code)

	if (!code)

		return -EINVAL;

		return -EINVAL;





	alu_op = meta->jump_neg_op ? ALU_OP_ADD : ALU_OP_SUB;

	carry_op = meta->jump_neg_op ? ALU_OP_ADD_C : ALU_OP_SUB_C;



	tmp_reg = ur_load_imm_any(nfp_prog, imm & ~0U, imm_b(nfp_prog));

	tmp_reg = ur_load_imm_any(nfp_prog, imm & ~0U, imm_b(nfp_prog));

	if (!code->swap)

	if (!code->swap)

		emit_alu(nfp_prog, reg_none(), reg_a(reg), ALU_OP_SUB, tmp_reg);

		emit_alu(nfp_prog, reg_none(), reg_a(reg), alu_op, tmp_reg);

	else

	else

		emit_alu(nfp_prog, reg_none(), tmp_reg, ALU_OP_SUB, reg_a(reg));

		emit_alu(nfp_prog, reg_none(), tmp_reg, alu_op, reg_a(reg));





	tmp_reg = ur_load_imm_any(nfp_prog, imm >> 32, imm_b(nfp_prog));

	tmp_reg = ur_load_imm_any(nfp_prog, imm >> 32, imm_b(nfp_prog));

	if (!code->swap)

	if (!code->swap)

		emit_alu(nfp_prog, reg_none(),

		emit_alu(nfp_prog, reg_none(),

			 reg_a(reg + 1), ALU_OP_SUB_C, tmp_reg);

			 reg_a(reg + 1), carry_op, tmp_reg);

	else

	else

		emit_alu(nfp_prog, reg_none(),

		emit_alu(nfp_prog, reg_none(),

			 tmp_reg, ALU_OP_SUB_C, reg_a(reg + 1));

			 tmp_reg, carry_op, reg_a(reg + 1));





	emit_br(nfp_prog, code->br_mask, insn->off, 0);

	emit_br(nfp_prog, code->br_mask, insn->off, 0);
@@ -2745,13 +2749,26 @@ static void nfp_bpf_opt_neg_add_sub(struct nfp_prog *nfp_prog) 
			continue;

			continue;





		if (BPF_CLASS(insn.code) != BPF_ALU &&

		if (BPF_CLASS(insn.code) != BPF_ALU &&

		    BPF_CLASS(insn.code) != BPF_ALU64)

		    BPF_CLASS(insn.code) != BPF_ALU64 &&

		    BPF_CLASS(insn.code) != BPF_JMP)

			continue;

			continue;

		if (BPF_SRC(insn.code) != BPF_K)

		if (BPF_SRC(insn.code) != BPF_K)

			continue;

			continue;

		if (insn.imm >= 0)

		if (insn.imm >= 0)

			continue;

			continue;





		if (BPF_CLASS(insn.code) == BPF_JMP) {

			switch (BPF_OP(insn.code)) {

			case BPF_JGE:

			case BPF_JSGE:

			case BPF_JLT:

			case BPF_JSLT:

				meta->jump_neg_op = true;

				break;

			default:

				continue;

			}

		} else {

			if (BPF_OP(insn.code) == BPF_ADD)

			if (BPF_OP(insn.code) == BPF_ADD)

				insn.code = BPF_CLASS(insn.code) | BPF_SUB;

				insn.code = BPF_CLASS(insn.code) | BPF_SUB;

			else if (BPF_OP(insn.code) == BPF_SUB)

			else if (BPF_OP(insn.code) == BPF_SUB)
@@ -2760,6 +2777,7 @@ static void nfp_bpf_opt_neg_add_sub(struct nfp_prog *nfp_prog) 
				continue;

				continue;





			meta->insn.code = insn.code | BPF_K;

			meta->insn.code = insn.code | BPF_K;

		}





		meta->insn.imm = -insn.imm;

		meta->insn.imm = -insn.imm;

	}

	}

drivers/net/ethernet/netronome/nfp/bpf/main.h

+5 −1
Original line number Original line Diff line number Diff line
@@ -236,6 +236,7 @@ struct nfp_bpf_reg_state { 
 * @xadd_over_16bit: 16bit immediate is not guaranteed

 * @xadd_over_16bit: 16bit immediate is not guaranteed

 * @xadd_maybe_16bit: 16bit immediate is possible

 * @xadd_maybe_16bit: 16bit immediate is possible

 * @jmp_dst: destination info for jump instructions

 * @jmp_dst: destination info for jump instructions

 * @jump_neg_op: jump instruction has inverted immediate, use ADD instead of SUB

 * @func_id: function id for call instructions

 * @func_id: function id for call instructions

 * @arg1: arg1 for call instructions

 * @arg1: arg1 for call instructions

 * @arg2: arg2 for call instructions

 * @arg2: arg2 for call instructions
@@ -264,7 +265,10 @@ struct nfp_insn_meta { 
			bool xadd_maybe_16bit;

			bool xadd_maybe_16bit;

		};

		};

		/* jump */

		/* jump */

		struct {

			struct nfp_insn_meta *jmp_dst;

			struct nfp_insn_meta *jmp_dst;

			bool jump_neg_op;

		};

		/* function calls */

		/* function calls */

		struct {

		struct {

			u32 func_id;

			u32 func_id;