Hi Björn, at least for me patch 3 didn't make it to the list.
On Tue, Jan 15, 2019 at 09:35:15AM +0100, Björn Töpel wrote: > Hi! > > I've been hacking on a RV64G eBPF JIT compiler, and would like some > feedback. > > Codewise, it needs some refactoring. Currently there's a bit too much > copy-and-paste going on, and I know some places where I could optimize > the code generation a bit (mostly BPF_K type of instructions, dealing > with immediates). > > From a features perspective, two things are missing: > > * tail calls > * "far-branches", i.e. conditional branches that reach beyond 13b. > > The test_bpf.ko (only tested on 4.20!) passes all tests. > > I've done all the tests on QEMU (version 3.1.50), so no real hardware. > > Some questions/observations: > > * I've added "HAVE_EFFICIENT_UNALIGNED_ACCESS" to > arch/riscv/Kconfig. Is this assumption correct? > > * emit_imm() just relies on lui, adds and shifts. No fancy xori cost > optimizations like GCC does. > > * Suggestions on how to implement the tail call, given that the > prologue/epilogue has variable size. I will dig into the details of > mips/arm64/x86. :-) > > Next steps (prior patch proper) is cleaning up the code, add tail > calls, and making sure that bpftool disassembly works correctly. > > All input are welcome. This is my first RISC-V hack, so I sure there > are a lot things to improve! > > > Thanks, > Björn > > > Björn Töpel (3): > riscv: set HAVE_EFFICIENT_UNALIGNED_ACCESS > riscv: add build infra for JIT compiler > bpf, riscv: added eBPF JIT for RV64G > > arch/riscv/Kconfig | 2 + > arch/riscv/Makefile | 4 + > arch/riscv/net/Makefile | 5 + > arch/riscv/net/bpf_jit_comp.c | 1612 +++++++++++++++++++++++++++++++++ > 4 files changed, 1623 insertions(+) > create mode 100644 arch/riscv/net/Makefile > create mode 100644 arch/riscv/net/bpf_jit_comp.c > > -- > 2.19.1 > > > _______________________________________________ > linux-riscv mailing list > linux-ri...@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-riscv ---end quoted text---
