net: filter: BPF testsuite

The testsuite covers classic and internal BPF instructions.
It is particularly useful for JIT compiler developers.
Adds to "net" selftest target.

The testsuite can be used as a set of micro-benchmarks.
It measures execution time of each BPF program in nsec.

This patch adds core framework.

Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

lib/Kconfig.debug

@@ -1620,6 +1620,19 @@ config TEST_USER_COPY
 
 	  If unsure, say N.
 
+config TEST_BPF
+	tristate "Test BPF filter functionality"
+	default n
+	depends on m
+	help
+	  This builds the "test_bpf" module that runs various test vectors
+	  against the BPF interpreter or BPF JIT compiler depending on the
+	  current setting. This is in particular useful for BPF JIT compiler
+	  development, but also to run regression tests against changes in
+	  the interpreter code.
+
+	  If unsure, say N.
+
 source "samples/Kconfig"
 
 source "lib/Kconfig.kgdb"