bpf: verifier (add docs)

this patch adds all of eBPF verfier documentation and empty bpf_check()

The end goal for the verifier is to statically check safety of the program.

Verifier will catch:
- loops
- out of range jumps
- unreachable instructions
- invalid instructions
- uninitialized register access
- uninitialized stack access
- misaligned stack access
- out of range stack access
- invalid calling convention

More details in Documentation/networking/filter.txt

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

1 files changed, 1 insertions, 1 deletions

diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index b513659d120f..74b3628c5fdb 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -507,7 +507,7 @@ static int bpf_prog_load(union bpf_attr *attr)
 		goto free_prog;
 
 	/* run eBPF verifier */
-	/* err = bpf_check(prog, tb); */
+	err = bpf_check(prog, attr);
 
 	if (err < 0)
 		goto free_used_maps;