bpf: mini eBPF library, test stubs and verifier testsuite

1.
the library includes a trivial set of BPF syscall wrappers:
int bpf_create_map(int key_size, int value_size, int max_entries);
int bpf_update_elem(int fd, void *key, void *value);
int bpf_lookup_elem(int fd, void *key, void *value);
int bpf_delete_elem(int fd, void *key);
int bpf_get_next_key(int fd, void *key, void *next_key);
int bpf_prog_load(enum bpf_prog_type prog_type,
		  const struct sock_filter_int *insns, int insn_len,
		  const char *license);
bpf_prog_load() stores verifier log into global bpf_log_buf[] array

and BPF_*() macros to build instructions

2.
test stubs configure eBPF infra with 'unspec' map and program types.
These are fake types used by user space testsuite only.

3.
verifier tests valid and invalid programs and expects predefined
error log messages from kernel.
40 tests so far.

$ sudo ./test_verifier
 #0 add+sub+mul OK
 #1 unreachable OK
 #2 unreachable2 OK
 #3 out of range jump OK
 #4 out of range jump2 OK
 #5 test1 ld_imm64 OK
 ...

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

1 files changed, 2 insertions, 1 deletions

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index a285900..3ac43f3 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1672,7 +1672,8 @@ config TEST_BPF
 	  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.
+	  the interpreter code. It also enables test stubs for eBPF maps and
+	  verifier used by user space verifier testsuite.
 
 	  If unsure, say N.