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Commit 0d49eaf4 authored by Jakub Kicinski's avatar Jakub Kicinski Committed by Daniel Borkmann
Browse files

nfp: bpf: add basic support for adjust head call 



Support bpf_xdp_adjust_head().  We need to check whether the
packet offset after adjustment is within datapath's limits.
We also check if the frame is at least ETH_HLEN long (similar
to the kernel implementation).

Signed-off-by: default avatarJakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
parent 2cb230bd

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

0 → 100644
+54 −0
Original line number Diff line number Diff line 
/*

 * Copyright (C) 2017 Netronome Systems, Inc.

 *

 * This software is dual licensed under the GNU General License Version 2,

 * June 1991 as shown in the file COPYING in the top-level directory of this

 * source tree or the BSD 2-Clause License provided below.  You have the

 * option to license this software under the complete terms of either license.

 *

 * The BSD 2-Clause License:

 *

 *     Redistribution and use in source and binary forms, with or

 *     without modification, are permitted provided that the following

 *     conditions are met:

 *

 *      1. Redistributions of source code must retain the above

 *         copyright notice, this list of conditions and the following

 *         disclaimer.

 *

 *      2. Redistributions in binary form must reproduce the above

 *         copyright notice, this list of conditions and the following

 *         disclaimer in the documentation and/or other materials

 *         provided with the distribution.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,

 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF

 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND

 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS

 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN

 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN

 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE

 * SOFTWARE.

 */



#ifndef NFP_BPF_FW_H

#define NFP_BPF_FW_H 1



#include <linux/bitops.h>

#include <linux/types.h>



enum bpf_cap_tlv_type {

	NFP_BPF_CAP_TYPE_ADJUST_HEAD	= 2,

};



struct nfp_bpf_cap_tlv_adjust_head {

	__le32 flags;

	__le32 off_min;

	__le32 off_max;

	__le32 guaranteed_sub;

	__le32 guaranteed_add;

};



#define NFP_BPF_ADJUST_HEAD_NO_META	BIT(0)



#endif

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

+73 −0
Original line number Diff line number Diff line
@@ -33,6 +33,7 @@ 


#define pr_fmt(fmt)	"NFP net bpf: " fmt



#include <linux/bug.h>

#include <linux/kernel.h>

#include <linux/bpf.h>

#include <linux/filter.h>
@@ -87,6 +88,18 @@ static unsigned int nfp_prog_current_offset(struct nfp_prog *nfp_prog) 
	return nfp_prog->start_off + nfp_prog->prog_len;

}



static bool

nfp_prog_confirm_current_offset(struct nfp_prog *nfp_prog, unsigned int off)

{

	/* If there is a recorded error we may have dropped instructions;

	 * that doesn't have to be due to translator bug, and the translation

	 * will fail anyway, so just return OK.

	 */

	if (nfp_prog->error)

		return true;

	return !WARN_ON_ONCE(nfp_prog_current_offset(nfp_prog) != off);

}



static unsigned int

nfp_prog_offset_to_index(struct nfp_prog *nfp_prog, unsigned int offset)

{
@@ -1196,6 +1209,64 @@ static void wrp_end32(struct nfp_prog *nfp_prog, swreg reg_in, u8 gpr_out) 
		      SHF_SC_R_ROT, 16);

}



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

{

	swreg tmp = imm_a(nfp_prog), tmp_len = imm_b(nfp_prog);

	struct nfp_bpf_cap_adjust_head *adjust_head;

	u32 ret_einval, end;



	adjust_head = &nfp_prog->bpf->adjust_head;



	ret_einval = nfp_prog_current_offset(nfp_prog) + 14;

	end = ret_einval + 2;



	/* We need to use a temp because offset is just a part of the pkt ptr */

	emit_alu(nfp_prog, tmp,

		 reg_a(2 * 2), ALU_OP_ADD_2B, pptr_reg(nfp_prog));



	/* Validate result will fit within FW datapath constraints */

	emit_alu(nfp_prog, reg_none(),

		 tmp, ALU_OP_SUB, reg_imm(adjust_head->off_min));

	emit_br(nfp_prog, BR_BLO, ret_einval, 0);

	emit_alu(nfp_prog, reg_none(),

		 reg_imm(adjust_head->off_max), ALU_OP_SUB, tmp);

	emit_br(nfp_prog, BR_BLO, ret_einval, 0);



	/* Validate the length is at least ETH_HLEN */

	emit_alu(nfp_prog, tmp_len,

		 plen_reg(nfp_prog), ALU_OP_SUB, reg_a(2 * 2));

	emit_alu(nfp_prog, reg_none(),

		 tmp_len, ALU_OP_SUB, reg_imm(ETH_HLEN));

	emit_br(nfp_prog, BR_BMI, ret_einval, 0);



	/* Load the ret code */

	wrp_immed(nfp_prog, reg_both(0), 0);

	wrp_immed(nfp_prog, reg_both(1), 0);



	/* Modify the packet metadata */

	emit_ld_field(nfp_prog, pptr_reg(nfp_prog), 0x3, tmp, SHF_SC_NONE, 0);



	/* Skip over the -EINVAL ret code (defer 2) */

	emit_br_def(nfp_prog, end, 2);



	emit_alu(nfp_prog, plen_reg(nfp_prog),

		 plen_reg(nfp_prog), ALU_OP_SUB, reg_a(2 * 2));

	emit_alu(nfp_prog, pv_len(nfp_prog),

		 pv_len(nfp_prog), ALU_OP_SUB, reg_a(2 * 2));



	/* return -EINVAL target */

	if (!nfp_prog_confirm_current_offset(nfp_prog, ret_einval))

		return -EINVAL;



	wrp_immed(nfp_prog, reg_both(0), -22);

	wrp_immed(nfp_prog, reg_both(1), ~0);



	if (!nfp_prog_confirm_current_offset(nfp_prog, end))

		return -EINVAL;



	return 0;

}



/* --- Callbacks --- */

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

{
@@ -1933,6 +2004,8 @@ static int jne_reg(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta) 
static int call(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta)

{

	switch (meta->insn.imm) {

	case BPF_FUNC_xdp_adjust_head:

		return adjust_head(nfp_prog, meta);

	default:

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

		return -EOPNOTSUPP;

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

+38 −0
Original line number Diff line number Diff line
@@ -39,6 +39,7 @@ 
#include "../nfp_main.h"

#include "../nfp_net.h"

#include "../nfp_port.h"

#include "fw.h"

#include "main.h"



static bool nfp_net_ebpf_capable(struct nfp_net *nn)
@@ -156,6 +157,36 @@ static bool nfp_bpf_tc_busy(struct nfp_app *app, struct nfp_net *nn) 
	return nn->dp.ctrl & NFP_NET_CFG_CTRL_BPF;

}



static int

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

			      u32 length)

{

	struct nfp_bpf_cap_tlv_adjust_head __iomem *cap = value;

	struct nfp_cpp *cpp = bpf->app->pf->cpp;



	if (length < sizeof(*cap)) {

		nfp_err(cpp, "truncated adjust_head TLV: %d\n", length);

		return -EINVAL;

	}



	bpf->adjust_head.flags = readl(&cap->flags);

	bpf->adjust_head.off_min = readl(&cap->off_min);

	bpf->adjust_head.off_max = readl(&cap->off_max);



	if (bpf->adjust_head.off_min > bpf->adjust_head.off_max) {

		nfp_err(cpp, "invalid adjust_head TLV: min > max\n");

		return -EINVAL;

	}

	if (!FIELD_FIT(UR_REG_IMM_MAX, bpf->adjust_head.off_min) ||

	    !FIELD_FIT(UR_REG_IMM_MAX, bpf->adjust_head.off_max)) {

		nfp_warn(cpp, "disabling adjust_head - driver expects min/max to fit in as immediates\n");

		memset(&bpf->adjust_head, 0, sizeof(bpf->adjust_head));

		return 0;

	}



	return 0;

}



static int nfp_bpf_parse_capabilities(struct nfp_app *app)

{

	struct nfp_cpp *cpp = app->pf->cpp;
@@ -169,16 +200,23 @@ static int nfp_bpf_parse_capabilities(struct nfp_app *app) 


	start = mem;

	while (mem - start + 8 < nfp_cpp_area_size(area)) {

		u8 __iomem *value;

		u32 type, length;



		type = readl(mem);

		length = readl(mem + 4);

		value = mem + 8;



		mem += 8 + length;

		if (mem - start > nfp_cpp_area_size(area))

			goto err_release_free;



		switch (type) {

		case NFP_BPF_CAP_TYPE_ADJUST_HEAD:

			if (nfp_bpf_parse_cap_adjust_head(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

+11 −0
Original line number Diff line number Diff line
@@ -81,9 +81,20 @@ enum pkt_vec { 
/**

 * struct nfp_app_bpf - bpf app priv structure

 * @app:		backpointer to the app

 *

 * @adjust_head:	adjust head capability

 * @flags:		extra flags for adjust head

 * @off_min:		minimal packet offset within buffer required

 * @off_max:		maximum packet offset within buffer required

 */

struct nfp_app_bpf {

	struct nfp_app *app;



	struct nfp_bpf_cap_adjust_head {

		u32 flags;

		int off_min;

		int off_max;

	} adjust_head;

};



struct nfp_prog;

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

+12 −0
Original line number Diff line number Diff line
@@ -38,6 +38,7 @@ 
#include <linux/kernel.h>

#include <linux/pkt_cls.h>



#include "fw.h"

#include "main.h"



struct nfp_insn_meta *
@@ -71,9 +72,20 @@ nfp_bpf_goto_meta(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta, 
static int

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

{

	struct nfp_app_bpf *bpf = nfp_prog->bpf;

	u32 func_id = meta->insn.imm;



	switch (func_id) {

	case BPF_FUNC_xdp_adjust_head:

		if (!bpf->adjust_head.off_max) {

			pr_warn("adjust_head not supported by FW\n");

			return -EOPNOTSUPP;

		}

		if (!(bpf->adjust_head.flags & NFP_BPF_ADJUST_HEAD_NO_META)) {

			pr_warn("adjust_head: FW requires shifting metadata, not supported by the driver\n");

			return -EOPNOTSUPP;

		}

		break;

	default:

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

		return -EOPNOTSUPP;