nfp: bpf: add basic support for adjust head call
authorJakub Kicinski <jakub.kicinski@netronome.com>
Fri, 15 Dec 2017 05:29:18 +0000 (21:29 -0800)
committerDaniel Borkmann <daniel@iogearbox.net>
Fri, 15 Dec 2017 13:18:18 +0000 (14:18 +0100)
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: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
drivers/net/ethernet/netronome/nfp/bpf/fw.h [new file with mode: 0644]
drivers/net/ethernet/netronome/nfp/bpf/jit.c
drivers/net/ethernet/netronome/nfp/bpf/main.c
drivers/net/ethernet/netronome/nfp/bpf/main.h
drivers/net/ethernet/netronome/nfp/bpf/verifier.c
drivers/net/ethernet/netronome/nfp/nfp_asm.h

diff --git a/drivers/net/ethernet/netronome/nfp/bpf/fw.h b/drivers/net/ethernet/netronome/nfp/bpf/fw.h
new file mode 100644 (file)
index 0000000..7206aa1
--- /dev/null
@@ -0,0 +1,54 @@
+/*
+ * 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
index 7afdc6d8e5ac7ecad30b9ee8ecc297ccbdb48a64..4bfcb1f3def83c075b647f69904b12f9e09a49ee 100644 (file)
@@ -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;
index f76bb40c20bc698362cf153b80c76ac293d1e4ba..bd4a1dcc58b3c9a8faf7ebcd9c16a227b4b51717 100644 (file)
@@ -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;
index a1a3f96353df08b69e10f5e76c0d178035d6f0e9..00a46258fb6d406f6c5a64df6a34c381b6a2d575 100644 (file)
@@ -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;
index 3b940b682ac3132eded27010d83d7655793875b5..0a457d98666c8868038ba25016827378188fcb42 100644 (file)
@@ -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;
index 3387e6926eb00d96524ac5713249a43dd5b4f6e0..a24daeab1a775840e382e14ff1db407764bd49f6 100644 (file)
@@ -77,6 +77,7 @@
 enum br_mask {
        BR_BEQ = 0x00,
        BR_BNE = 0x01,
+       BR_BMI = 0x02,
        BR_BHS = 0x04,
        BR_BLO = 0x05,
        BR_BGE = 0x08,
@@ -175,6 +176,7 @@ enum alu_op {
        ALU_OP_NONE     = 0x00,
        ALU_OP_ADD      = 0x01,
        ALU_OP_NOT      = 0x04,
+       ALU_OP_ADD_2B   = 0x05,
        ALU_OP_AND      = 0x08,
        ALU_OP_SUB_C    = 0x0d,
        ALU_OP_ADD_C    = 0x11,