4 files changed, 147 insertions, 5 deletions

diff --git a/drivers/net/ethernet/netronome/nfp/bpf/jit.c b/drivers/net/ethernet/netronome/nfp/bpf/jit.c
index eb8c905936ac..d2a3e9065dbe 100644
--- a/drivers/net/ethernet/netronome/nfp/bpf/jit.c
+++ b/drivers/net/ethernet/netronome/nfp/bpf/jit.c
@@ -642,6 +642,100 @@ data_st_host_order(struct nfp_prog *nfp_prog, u8 dst_gpr, swreg offset,
 	return 0;
 }
 
+typedef int
+(*lmem_step)(struct nfp_prog *nfp_prog, u8 gpr, u8 gpr_byte, s32 off,
+	     unsigned int size);
+
+static int
+wrp_lmem_store(struct nfp_prog *nfp_prog, u8 src, u8 src_byte, s32 off,
+	       unsigned int size)
+{
+	u32 idx, dst_byte;
+	enum shf_sc sc;
+	swreg reg;
+	int shf;
+	u8 mask;
+
+	if (WARN_ON_ONCE(src_byte + size > 4 || off % 4 + size > 4))
+		return -EOPNOTSUPP;
+
+	idx = off / 4;
+
+	/* Move the entire word */
+	if (size == 4) {
+		wrp_mov(nfp_prog, reg_lm(0, idx), reg_b(src));
+		return 0;
+	}
+
+	dst_byte = off % 4;
+
+	mask = (1 << size) - 1;
+	mask <<= dst_byte;
+
+	if (WARN_ON_ONCE(mask > 0xf))
+		return -EOPNOTSUPP;
+
+	shf = abs(src_byte - dst_byte) * 8;
+	if (src_byte == dst_byte) {
+		sc = SHF_SC_NONE;
+	} else if (src_byte < dst_byte) {
+		shf = 32 - shf;
+		sc = SHF_SC_L_SHF;
+	} else {
+		sc = SHF_SC_R_SHF;
+	}
+
+	/* ld_field can address fewer indexes, if offset too large do RMW.
+	 * Because we RMV twice we waste 2 cycles on unaligned 8 byte writes.
+	 */
+	if (idx <= RE_REG_LM_IDX_MAX) {
+		reg = reg_lm(0, idx);
+	} else {
+		reg = imm_a(nfp_prog);
+		wrp_mov(nfp_prog, reg, reg_lm(0, idx));
+	}
+
+	emit_ld_field(nfp_prog, reg, mask, reg_b(src), sc, shf);
+
+	if (idx > RE_REG_LM_IDX_MAX)
+		wrp_mov(nfp_prog, reg_lm(0, idx), reg);
+
+	return 0;
+}
+
+static int
+mem_op_stack(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta,
+	     unsigned int size, u8 gpr, lmem_step step)
+{
+	s32 off = nfp_prog->stack_depth + meta->insn.off;
+	u32 gpr_byte = 0;
+	int ret;
+
+	while (size) {
+		u32 slice_end;
+		u8 slice_size;
+
+		slice_size = min(size, 4 - gpr_byte);
+		slice_end = min(off + slice_size, round_up(off + 1, 4));
+		slice_size = slice_end - off;
+
+		ret = step(nfp_prog, gpr, gpr_byte, off, slice_size);
+		if (ret)
+			return ret;
+
+		gpr_byte += slice_size;
+		if (gpr_byte >= 4) {
+			gpr_byte -= 4;
+			gpr++;
+		}
+
+		size -= slice_size;
+		off += slice_size;
+	}
+
+	return 0;
+}
+
 static void
 wrp_alu_imm(struct nfp_prog *nfp_prog, u8 dst, enum alu_op alu_op, u32 imm)
 {
@@ -1299,12 +1393,23 @@ mem_stx_data(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta,
 }
 
 static int
+mem_stx_stack(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta,
+	      unsigned int size)
+{
+	return mem_op_stack(nfp_prog, meta, size, meta->insn.src_reg * 2,
+			    wrp_lmem_store);
+}
+
+static int
 mem_stx(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta,
 	unsigned int size)
 {
 	if (meta->ptr.type == PTR_TO_PACKET)
 		return mem_stx_data(nfp_prog, meta, size);
 
+	if (meta->ptr.type == PTR_TO_STACK)
+		return mem_stx_stack(nfp_prog, meta, size);
+
 	return -EOPNOTSUPP;
 }
 
diff --git a/drivers/net/ethernet/netronome/nfp/bpf/main.h b/drivers/net/ethernet/netronome/nfp/bpf/main.h
index d77e88a45409..a31632681e79 100644
--- a/drivers/net/ethernet/netronome/nfp/bpf/main.h
+++ b/drivers/net/ethernet/netronome/nfp/bpf/main.h
@@ -151,6 +151,7 @@ static inline u8 mbpf_mode(const struct nfp_insn_meta *meta)
  * @tgt_done: jump target to get the next packet
  * @n_translated: number of successfully translated instructions (for errors)
  * @error: error code if something went wrong
+ * @stack_depth: max stack depth from the verifier
  * @insns: list of BPF instruction wrappers (struct nfp_insn_meta)
  */
 struct nfp_prog {
@@ -171,6 +172,8 @@ struct nfp_prog {
 	unsigned int n_translated;
 	int error;
 
+	unsigned int stack_depth;
+
 	struct list_head insns;
 };
 
diff --git a/drivers/net/ethernet/netronome/nfp/bpf/offload.c b/drivers/net/ethernet/netronome/nfp/bpf/offload.c
index a88bb5bc0082..f215abcbc18e 100644
--- a/drivers/net/ethernet/netronome/nfp/bpf/offload.c
+++ b/drivers/net/ethernet/netronome/nfp/bpf/offload.c
@@ -146,6 +146,7 @@ nfp_net_bpf_offload_prepare(struct nfp_net *nn,
 {
 	unsigned int code_sz = max_instr * sizeof(u64);
 	enum nfp_bpf_action_type act;
+	unsigned int stack_size;
 	u16 start_off, done_off;
 	unsigned int max_mtu;
 	int ret;
@@ -167,6 +168,19 @@ nfp_net_bpf_offload_prepare(struct nfp_net *nn,
 	start_off = nn_readw(nn, NFP_NET_CFG_BPF_START);
 	done_off = nn_readw(nn, NFP_NET_CFG_BPF_DONE);
 
+	if (cls_bpf->prog->aux->stack_depth > 64) {
+		nn_info(nn, "large stack not supported: program %dB > 64B\n",
+			cls_bpf->prog->aux->stack_depth);
+		return -EOPNOTSUPP;
+	}
+
+	stack_size = nn_readb(nn, NFP_NET_CFG_BPF_STACK_SZ) * 64;
+	if (cls_bpf->prog->aux->stack_depth > stack_size) {
+		nn_info(nn, "stack too large: program %dB > FW stack %dB\n",
+			cls_bpf->prog->aux->stack_depth, stack_size);
+		return -EOPNOTSUPP;
+	}
+
 	*code = dma_zalloc_coherent(nn->dp.dev, code_sz, dma_addr, GFP_KERNEL);
 	if (!*code)
 		return -ENOMEM;
diff --git a/drivers/net/ethernet/netronome/nfp/bpf/verifier.c b/drivers/net/ethernet/netronome/nfp/bpf/verifier.c
index 4d2ed84a82e0..376d9938b823 100644
--- a/drivers/net/ethernet/netronome/nfp/bpf/verifier.c
+++ b/drivers/net/ethernet/netronome/nfp/bpf/verifier.c
@@ -111,18 +111,41 @@ nfp_bpf_check_exit(struct nfp_prog *nfp_prog,
 	return 0;
 }
 
+static int nfp_bpf_check_stack_access(const struct bpf_reg_state *reg)
+{
+	if (!tnum_is_const(reg->var_off)) {
+		pr_info("variable ptr stack access\n");
+		return -EINVAL;
+	}
+
+	if (reg->var_off.value || reg->off) {
+		pr_info("stack access via modified register\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
 static int
 nfp_bpf_check_ptr(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta,
 		  const struct bpf_verifier_env *env, u8 reg_no)
 {
 	const struct bpf_reg_state *reg = &env->cur_state.regs[reg_no];
+	int err;
 
 	if (reg->type != PTR_TO_CTX &&
+	    reg->type != PTR_TO_STACK &&
 	    reg->type != PTR_TO_PACKET) {
 		pr_info("unsupported ptr type: %d\n", reg->type);
 		return -EINVAL;
 	}
 
+	if (reg->type == PTR_TO_STACK) {
+		err = nfp_bpf_check_stack_access(reg);
+		if (err)
+			return err;
+	}
+
 	if (meta->ptr.type != NOT_INIT && meta->ptr.type != reg->type) {
 		pr_info("ptr type changed for instruction %d -> %d\n",
 			meta->ptr.type, reg->type);
@@ -143,11 +166,6 @@ nfp_verify_insn(struct bpf_verifier_env *env, int insn_idx, int prev_insn_idx)
 	meta = nfp_bpf_goto_meta(priv->prog, meta, insn_idx, env->prog->len);
 	priv->meta = meta;
 
-	if (meta->insn.src_reg == BPF_REG_10 ||
-	    meta->insn.dst_reg == BPF_REG_10) {
-		pr_err("stack not yet supported\n");
-		return -EINVAL;
-	}
 	if (meta->insn.src_reg >= MAX_BPF_REG ||
 	    meta->insn.dst_reg >= MAX_BPF_REG) {
 		pr_err("program uses extended registers - jit hardening?\n");
@@ -176,6 +194,8 @@ int nfp_prog_verify(struct nfp_prog *nfp_prog, struct bpf_prog *prog)
 	struct nfp_bpf_analyzer_priv *priv;
 	int ret;
 
+	nfp_prog->stack_depth = prog->aux->stack_depth;
+
 	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
 	if (!priv)
 		return -ENOMEM;