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Commit df4a37d8 authored by Jakub Kicinski's avatar Jakub Kicinski Committed by Alexei Starovoitov
Browse files

nfp: bpf: add support for bpf_get_prandom_u32() 



NFP has a prng register, which we can read to obtain a u32 worth
of pseudo random data.  Generate code for it.

Signed-off-by: default avatarJakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: default avatarQuentin Monnet <quentin.monnet@netronome.com>
Reviewed-by: default avatarJiong Wang <jiong.wang@netronome.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 41aed09c

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

+1 −0
Original line number Diff line number Diff line
@@ -41,6 +41,7 @@ enum bpf_cap_tlv_type { 
	NFP_BPF_CAP_TYPE_FUNC		= 1,

	NFP_BPF_CAP_TYPE_ADJUST_HEAD	= 2,

	NFP_BPF_CAP_TYPE_MAPS		= 3,

	NFP_BPF_CAP_TYPE_RANDOM		= 4,

};



struct nfp_bpf_cap_tlv_func {

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

+22 −2
Original line number Diff line number Diff line
@@ -405,7 +405,7 @@ __emit_lcsr(struct nfp_prog *nfp_prog, u16 areg, u16 breg, bool wr, u16 addr, 
		FIELD_PREP(OP_LCSR_A_SRC, areg) |

		FIELD_PREP(OP_LCSR_B_SRC, breg) |

		FIELD_PREP(OP_LCSR_WRITE, wr) |

		FIELD_PREP(OP_LCSR_ADDR, addr) |

		FIELD_PREP(OP_LCSR_ADDR, addr / 4) |

		FIELD_PREP(OP_LCSR_SRC_LMEXTN, src_lmextn) |

		FIELD_PREP(OP_LCSR_DST_LMEXTN, dst_lmextn);
@@ -433,10 +433,16 @@ static void emit_csr_wr(struct nfp_prog *nfp_prog, swreg src, u16 addr) 
		return;

	}



	__emit_lcsr(nfp_prog, reg.areg, reg.breg, true, addr / 4,

	__emit_lcsr(nfp_prog, reg.areg, reg.breg, true, addr,

		    false, reg.src_lmextn);

}



/* CSR value is read in following immed[gpr, 0] */

static void __emit_csr_rd(struct nfp_prog *nfp_prog, u16 addr)

{

	__emit_lcsr(nfp_prog, 0, 0, false, addr, false, false);

}



static void emit_nop(struct nfp_prog *nfp_prog)

{

	__emit_immed(nfp_prog, UR_REG_IMM, UR_REG_IMM, 0, 0, 0, 0, 0, 0, 0);
@@ -1398,6 +1404,18 @@ map_call_stack_common(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta) 
	return 0;

}



static int

nfp_get_prandom_u32(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta)

{

	__emit_csr_rd(nfp_prog, NFP_CSR_PSEUDO_RND_NUM);

	/* CSR value is read in following immed[gpr, 0] */

	emit_immed(nfp_prog, reg_both(0), 0,

		   IMMED_WIDTH_ALL, false, IMMED_SHIFT_0B);

	emit_immed(nfp_prog, reg_both(1), 0,

		   IMMED_WIDTH_ALL, false, IMMED_SHIFT_0B);

	return 0;

}



/* --- Callbacks --- */

static int mov_reg64(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta)

{
@@ -2431,6 +2449,8 @@ static int call(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta) 
	case BPF_FUNC_map_update_elem:

	case BPF_FUNC_map_delete_elem:

		return map_call_stack_common(nfp_prog, meta);

	case BPF_FUNC_get_prandom_u32:

		return nfp_get_prandom_u32(nfp_prog, meta);

	default:

		WARN_ONCE(1, "verifier allowed unsupported function\n");

		return -EOPNOTSUPP;

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

+12 −0
Original line number Diff line number Diff line
@@ -315,6 +315,14 @@ nfp_bpf_parse_cap_maps(struct nfp_app_bpf *bpf, void __iomem *value, u32 length) 
	return 0;

}



static int

nfp_bpf_parse_cap_random(struct nfp_app_bpf *bpf, void __iomem *value,

			 u32 length)

{

	bpf->pseudo_random = true;

	return 0;

}



static int nfp_bpf_parse_capabilities(struct nfp_app *app)

{

	struct nfp_cpp *cpp = app->pf->cpp;
@@ -353,6 +361,10 @@ static int nfp_bpf_parse_capabilities(struct nfp_app *app) 
			if (nfp_bpf_parse_cap_maps(app->priv, value, length))

				goto err_release_free;

			break;

		case NFP_BPF_CAP_TYPE_RANDOM:

			if (nfp_bpf_parse_cap_random(app->priv, value, length))

				goto err_release_free;

			break;

		default:

			nfp_dbg(cpp, "unknown BPF capability: %d\n", type);

			break;

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

+4 −0
Original line number Diff line number Diff line
@@ -133,6 +133,8 @@ enum pkt_vec { 
 * @helpers.map_lookup:		map lookup helper address

 * @helpers.map_update:		map update helper address

 * @helpers.map_delete:		map delete helper address

 *

 * @pseudo_random:	FW initialized the pseudo-random machinery (CSRs)

 */

struct nfp_app_bpf {

	struct nfp_app *app;
@@ -170,6 +172,8 @@ struct nfp_app_bpf { 
		u32 map_update;

		u32 map_delete;

	} helpers;



	bool pseudo_random;

};



enum nfp_bpf_map_use {

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

+7 −0
Original line number Diff line number Diff line
@@ -209,6 +209,13 @@ nfp_bpf_check_call(struct nfp_prog *nfp_prog, struct bpf_verifier_env *env, 
					  meta->func_id ? &meta->arg2 : NULL))

			return -EOPNOTSUPP;

		break;



	case BPF_FUNC_get_prandom_u32:

		if (bpf->pseudo_random)

			break;

		pr_vlog(env, "bpf_get_prandom_u32(): FW doesn't support random number generation\n");

		return -EOPNOTSUPP;



	default:

		pr_vlog(env, "unsupported function id: %d\n", func_id);

		return -EOPNOTSUPP;