nfp: bpf: copy range info for all operands of all ALU operations

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>

diff --git a/drivers/net/ethernet/netronome/nfp/bpf/main.h b/drivers/net/ethernet/netronome/nfp/bpf/main.h
index 5975a19c28cbb5013acc0511546498bd5a0dc756..c985d0ac61a3db3f7720fffe59837bb0868720d5 100644 (file)
--- 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 nfp_insn_meta *meta)
        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 struct nfp_insn_meta *meta)
        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

diff --git a/drivers/net/ethernet/netronome/nfp/bpf/offload.c b/drivers/net/ethernet/netronome/nfp/bpf/offload.c
index 856a0003bb754a4d2281566f5fc7273a8cde0152..78f44c4d95b4914755dfeb806c8d5e85f5463e65 100644 (file)
--- 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_prog, const struct bpf_insn *prog,
 
                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);
        }

diff --git a/drivers/net/ethernet/netronome/nfp/bpf/verifier.c b/drivers/net/ethernet/netronome/nfp/bpf/verifier.c
index e862b739441f40380012cc8095d5dadb0879effd..7bd9666bd8ff450a87dfd1242cae4e4a8e49bbdb 100644 (file)
--- 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 *env, int insn_idx, int prev_insn_idx)
        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;