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

Commit f43d0f17 authored by Jiong Wang's avatar Jiong Wang Committed by Daniel Borkmann
Browse files

nfp: bpf: support arithmetic right shift by constant (BPF_ARSH | BPF_K) 



Code logic is similar with logic right shift except we also need to set
PREV_ALU result properly, the MSB of which is the bit that will be
replicated to fill in all the vacant positions.

Signed-off-by: default avatarJiong Wang <jiong.wang@netronome.com>
Reviewed-by: default avatarJakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
parent 991f5b36

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

+34 −0
Original line number Diff line number Diff line
@@ -1916,6 +1916,39 @@ static int shr_reg64(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta) 
	return 0;

}



/* Code logic is the same as __shr_imm64 except ashr requires signedness bit

 * told through PREV_ALU result.

 */

static int ashr_imm64(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta)

{

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

	u8 dst = insn->dst_reg * 2;



	if (insn->imm < 32) {

		emit_shf(nfp_prog, reg_both(dst), reg_a(dst + 1), SHF_OP_NONE,

			 reg_b(dst), SHF_SC_R_DSHF, insn->imm);

		/* Set signedness bit. */

		emit_alu(nfp_prog, reg_none(), reg_a(dst + 1), ALU_OP_OR,

			 reg_imm(0));

		emit_shf(nfp_prog, reg_both(dst + 1), reg_none(), SHF_OP_ASHR,

			 reg_b(dst + 1), SHF_SC_R_SHF, insn->imm);

	} else if (insn->imm == 32) {

		/* NOTE: this also helps setting signedness bit. */

		wrp_reg_mov(nfp_prog, dst, dst + 1);

		emit_shf(nfp_prog, reg_both(dst + 1), reg_none(), SHF_OP_ASHR,

			 reg_b(dst + 1), SHF_SC_R_SHF, 31);

	} else if (insn->imm > 32) {

		emit_alu(nfp_prog, reg_none(), reg_a(dst + 1), ALU_OP_OR,

			 reg_imm(0));

		emit_shf(nfp_prog, reg_both(dst), reg_none(), SHF_OP_ASHR,

			 reg_b(dst + 1), SHF_SC_R_SHF, insn->imm - 32);

		emit_shf(nfp_prog, reg_both(dst + 1), reg_none(), SHF_OP_ASHR,

			 reg_b(dst + 1), SHF_SC_R_SHF, 31);

	}



	return 0;

}



static int mov_reg(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta)

{

	const struct bpf_insn *insn = &meta->insn;
@@ -2742,6 +2775,7 @@ static const instr_cb_t instr_cb[256] = { 
	[BPF_ALU64 | BPF_LSH | BPF_K] =	shl_imm64,

	[BPF_ALU64 | BPF_RSH | BPF_X] =	shr_reg64,

	[BPF_ALU64 | BPF_RSH | BPF_K] =	shr_imm64,

	[BPF_ALU64 | BPF_ARSH | BPF_K] = ashr_imm64,

	[BPF_ALU | BPF_MOV | BPF_X] =	mov_reg,

	[BPF_ALU | BPF_MOV | BPF_K] =	mov_imm,

	[BPF_ALU | BPF_XOR | BPF_X] =	xor_reg,

drivers/net/ethernet/netronome/nfp/nfp_asm.h

+1 −0
Original line number Diff line number Diff line
@@ -174,6 +174,7 @@ enum shf_op { 
	SHF_OP_NONE = 0,

	SHF_OP_AND = 2,

	SHF_OP_OR = 5,

	SHF_OP_ASHR = 6,

};



enum shf_sc {