tree d6a8648b1dcc509a47e47f995159f70bcb0572c6
parent 6fb2a756739aa507c1fd5b8126f0bfc2f070dc46
author Alexei Starovoitov <ast@plumgrid.com> 1417301173 -0800
committer David S. Miller <davem@davemloft.net> 1417843434 -0800

bpf: x86: fix epilogue generation for eBPF programs

classic BPF has a restriction that last insn is always BPF_RET.
eBPF doesn't have BPF_RET instruction and this restriction.
It has BPF_EXIT insn which can appear anywhere in the program
one or more times and it doesn't have to be last insn.
Fix eBPF JIT to emit epilogue when first BPF_EXIT is seen
and all other BPF_EXIT instructions will be emitted as jump.

Since jump offset to epilogue is computed as:
jmp_offset = ctx->cleanup_addr - addrs[i]
we need to change type of cleanup_addr to signed to compute the offset as:
(long long) ((int)20 - (int)30)
instead of:
(long long) ((unsigned int)20 - (int)30)

Fixes: 622582786c9e ("net: filter: x86: internal BPF JIT")
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>