• Matt Evans's avatar
    net: filter: BPF 'JIT' compiler for PPC64 · 0ca87f05
    Matt Evans authored
    An implementation of a code generator for BPF programs to speed up packet
    filtering on PPC64, inspired by Eric Dumazet's x86-64 version.
    
    Filter code is generated as an ABI-compliant function in module_alloc()'d mem
    with stackframe & prologue/epilogue generated if required (simple filters don't
    need anything more than an li/blr).  The filter's local variables, M[], live in
    registers.  Supports all BPF opcodes, although "complicated" loads from negative
    packet offsets (e.g. SKF_LL_OFF) are not yet supported.
    
    There are a couple of further optimisations left for future work; many-pass
    assembly with branch-reach reduction and a register allocator to push M[]
    variables into volatile registers would improve the code quality further.
    
    This currently supports big-endian 64-bit PowerPC only (but is fairly simple
    to port to PPC32 or LE!).
    
    Enabled in the same way as x86-64:
    
    	echo 1 > /proc/sys/net/core/bpf_jit_enable
    
    Or, enabled with extra debug output:
    
    	echo 2 > /proc/sys/net/core/bpf_jit_enable
    Signed-off-by: default avatarMatt Evans <matt@ozlabs.org>
    Acked-by: default avatarEric Dumazet <eric.dumazet@gmail.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    0ca87f05
bpf_jit.h 8.29 KB