From: Jiong Wang <jiong.wang@netronome.com>
Date: Fri, 6 Jul 2018 15:13:20 -0700
Subject: nfp: bpf: copy range info for all operands of all ALU operations
Patch-mainline: v4.19-rc1
Git-commit: 33b94310586b761fd04de0ef951d2f5d764b9b2a
References: bsc#1109837

NFP verifier hook is coping range information of the shift amount for
indirect shift operation so optimized shift sequences could be generated.

We want to use range info to do more things. For example, to decide whether
multiplication and divide are supported on the given range.

This patch simply let NFP verifier hook to copy range info for all operands
of all ALU operands.

Signed-off-by: Jiong Wang <jiong.wang@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/net/ethernet/netronome/nfp/bpf/main.h     |   33 ++++++++--------------
 drivers/net/ethernet/netronome/nfp/bpf/offload.c  |    4 ++
 drivers/net/ethernet/netronome/nfp/bpf/verifier.c |    6 +++-
 3 files changed, 20 insertions(+), 23 deletions(-)

--- a/drivers/net/ethernet/netronome/nfp/bpf/main.h
+++ b/drivers/net/ethernet/netronome/nfp/bpf/main.h
@@ -265,6 +265,8 @@ struct nfp_bpf_reg_state {
  * @arg2: arg2 for call instructions
  * @umin_src: copy of core verifier umin_value for src opearnd.
  * @umax_src: copy of core verifier umax_value for src operand.
+ * @umin_dst: copy of core verifier umin_value for dst opearnd.
+ * @umax_dst: copy of core verifier umax_value for dst operand.
  * @off: index of first generated machine instruction (in nfp_prog.prog)
  * @n: eBPF instruction number
  * @flags: eBPF instruction extra optimization flags
@@ -300,12 +302,15 @@ struct nfp_insn_meta {
 			struct bpf_reg_state arg1;
 			struct nfp_bpf_reg_state arg2;
 		};
-		/* We are interested in range info for some operands,
-		 * for example, the shift amount which is kept in src operand.
+		/* We are interested in range info for operands of ALU
+		 * operations. For example, shift amount, multiplicand and
+		 * multiplier etc.
 		 */
 		struct {
 			u64 umin_src;
 			u64 umax_src;
+			u64 umin_dst;
+			u64 umax_dst;
 		};
 	};
 	unsigned int off;
@@ -339,6 +344,11 @@ static inline u8 mbpf_mode(const struct
 	return BPF_MODE(meta->insn.code);
 }
 
+static inline bool is_mbpf_alu(const struct nfp_insn_meta *meta)
+{
+	return mbpf_class(meta) == BPF_ALU64 || mbpf_class(meta) == BPF_ALU;
+}
+
 static inline bool is_mbpf_load(const struct nfp_insn_meta *meta)
 {
 	return (meta->insn.code & ~BPF_SIZE_MASK) == (BPF_LDX | BPF_MEM);
@@ -384,25 +394,6 @@ static inline bool is_mbpf_xadd(const st
 	return (meta->insn.code & ~BPF_SIZE_MASK) == (BPF_STX | BPF_XADD);
 }
 
-static inline bool is_mbpf_indir_shift(const struct nfp_insn_meta *meta)
-{
-	u8 code = meta->insn.code;
-	bool is_alu, is_shift;
-	u8 opclass, opcode;
-
-	opclass = BPF_CLASS(code);
-	is_alu = opclass == BPF_ALU64 || opclass == BPF_ALU;
-	if (!is_alu)
-		return false;
-
-	opcode = BPF_OP(code);
-	is_shift = opcode == BPF_LSH || opcode == BPF_RSH || opcode == BPF_ARSH;
-	if (!is_shift)
-		return false;
-
-	return BPF_SRC(code) == BPF_X;
-}
-
 /**
  * struct nfp_prog - nfp BPF program
  * @bpf: backpointer to the bpf app priv structure
--- a/drivers/net/ethernet/netronome/nfp/bpf/offload.c
+++ b/drivers/net/ethernet/netronome/nfp/bpf/offload.c
@@ -190,8 +190,10 @@ nfp_prog_prepare(struct nfp_prog *nfp_pr
 
 		meta->insn = prog[i];
 		meta->n = i;
-		if (is_mbpf_indir_shift(meta))
+		if (is_mbpf_alu(meta)) {
 			meta->umin_src = U64_MAX;
+			meta->umin_dst = U64_MAX;
+		}
 
 		list_add_tail(&meta->l, &nfp_prog->insns);
 	}
--- a/drivers/net/ethernet/netronome/nfp/bpf/verifier.c
+++ b/drivers/net/ethernet/netronome/nfp/bpf/verifier.c
@@ -551,12 +551,16 @@ nfp_verify_insn(struct bpf_verifier_env
 	if (is_mbpf_xadd(meta))
 		return nfp_bpf_check_xadd(nfp_prog, meta, env);
 
-	if (is_mbpf_indir_shift(meta)) {
+	if (is_mbpf_alu(meta)) {
 		const struct bpf_reg_state *sreg =
 			cur_regs(env) + meta->insn.src_reg;
+		const struct bpf_reg_state *dreg =
+			cur_regs(env) + meta->insn.dst_reg;
 
 		meta->umin_src = min(meta->umin_src, sreg->umin_value);
 		meta->umax_src = max(meta->umax_src, sreg->umax_value);
+		meta->umin_dst = min(meta->umin_dst, dreg->umin_value);
+		meta->umax_dst = max(meta->umax_dst, dreg->umax_value);
 	}
 
 	return 0;