On Tue, 07 Mar 2017 12:40:03 +0100 Daniel Borkmann <[email protected]> wrote:
> On 03/07/2017 12:07 PM, Jesper Dangaard Brouer via iovisor-dev wrote: > > On Mon, 6 Mar 2017 16:14:06 -0800 > > Alexei Starovoitov via iovisor-dev <[email protected]> wrote: > [...] > >> that's practically impossible to know in advance, since hardening and > >> start address randomization will play a role. > >> Or use sysctl net.core.bpf_jit_enable=2 > >> at load time which gives raw x86 hex. > > > > The sysctl adjusting sounds interesting: > > > > sysctl net.core.bpf_jit_enable=2 > > > > What is below "proglen=335" the JIT'ed asm-code size? > > It's in bpf_jit_dump(): proglen is the len of opcode sequence generated > and flen is the number of bpf insns. You can use tools/net/bpf_jit_disasm.c > to disassemble that output. bpf_jit_disasm -o will dump the related opcodes > as well. Thanks for input, added: https://github.com/netoptimizer/prototype-kernel/commit/0b31532f42cd8 > > flen=55 proglen=335 pass=4 image=ffffffffa0006820 from=xdp_ddos01_blac > > pid=13333 > > JIT code: 00000000: 55 48 89 e5 48 81 ec 28 02 00 00 48 89 9d d8 fd > > JIT code: 00000010: ff ff 4c 89 ad e0 fd ff ff 4c 89 b5 e8 fd ff ff > > JIT code: 00000020: 4c 89 bd f0 fd ff ff 31 c0 48 89 85 f8 fd ff ff > > JIT code: 00000030: bb 02 00 00 00 48 8b 77 08 48 8b 7f 00 48 89 fa > > JIT code: 00000040: 48 83 c2 0e 48 39 f2 0f 87 e1 00 00 00 48 0f b6 > > JIT code: 00000050: 4f 0c 48 0f b6 57 0d 48 c1 e2 08 48 09 ca 48 89 > > JIT code: 00000060: d1 48 81 e1 ff 00 00 00 41 b8 06 00 00 00 49 39 > > JIT code: 00000070: c8 0f 87 b7 00 00 00 48 81 fa 88 a8 00 00 74 0e > > JIT code: 00000080: b9 0e 00 00 00 48 81 fa 81 00 00 00 75 1a 48 89 > > JIT code: 00000090: fa 48 83 c2 12 48 39 f2 0f 87 90 00 00 00 b9 12 > > JIT code: 000000a0: 00 00 00 48 0f b7 57 10 bb 02 00 00 00 48 81 e2 > > JIT code: 000000b0: ff ff 00 00 48 83 fa 08 75 49 48 01 cf 31 db 48 > > JIT code: 000000c0: 89 fa 48 83 c2 14 48 39 f2 77 38 8b 7f 0c 89 7d > > JIT code: 000000d0: fc 48 89 ee 48 83 c6 fc 48 bf 00 9c 24 5f 07 88 > > JIT code: 000000e0: ff ff e8 29 cd 13 e1 bb 02 00 00 00 48 83 f8 00 > > JIT code: 000000f0: 74 11 48 8b 78 00 48 83 c7 01 48 89 78 00 bb 01 > > JIT code: 00000100: 00 00 00 89 5d f8 48 89 ee 48 83 c6 f8 48 bf c0 > > JIT code: 00000110: 76 12 13 04 88 ff ff e8 f4 cc 13 e1 48 83 f8 00 > > JIT code: 00000120: 74 0c 48 8b 78 00 48 83 c7 01 48 89 78 00 48 89 > > JIT code: 00000130: d8 48 8b 9d d8 fd ff ff 4c 8b ad e0 fd ff ff 4c > > JIT code: 00000140: 8b b5 e8 fd ff ff 4c 8b bd f0 fd ff ff c9 c3 > > > > $ echo $((0x140)) > > 320 > > $ echo $((0x140 + 15)) > > 335 > > > > Using same example code, thus BPF instructions-size was 440 bytes, so > > the JIT'ed code size does get smaller. > > > -- Best regards, Jesper Dangaard Brouer MSc.CS, Principal Kernel Engineer at Red Hat LinkedIn: http://www.linkedin.com/in/brouer _______________________________________________ iovisor-dev mailing list [email protected] https://lists.iovisor.org/mailman/listinfo/iovisor-dev
