[RFC PATCH bpf-next 0/4] Support bpf trampoline for RV64

[Pu Lehui]

On 2022/12/19 21:37, Pu Lehui wrote:
> BPF trampoline is the critical infrastructure of the bpf
> subsystem, acting as a mediator between kernel functions
> and BPF programs. Numerous important features, such as
> using ebpf program for zero overhead kernel introspection,
> rely on this key component. We can't wait to support bpf
> trampoline on RV64. The implementation of bpf trampoline
> was closely to x86 and arm64 for future development.
> 
> As most of riscv cpu support unaligned memory accesses,
> we temporarily use patch [1] to facilitate testing. The
> test results are as follow, and test_verifier with no
> new failure ceses.
> 
> - fexit_test:OK
> - fentry_test:OK
> - fentry_fexit:OK
> - fexit_stress:OK
> - fexit_bpf2bpf:OK
> - dummy_st_ops:OK
> - modify_return:OK
> - get_func_ip_test:OK
> - get_func_args_test:OK
> - trampoline_count:OK
> 
> [1] https://lore.kernel.org/linux-riscv/20210916130855.4054926-2-chenhuang5@huawei.com/
> 
> Pu Lehui (4):
>    bpf: Rollback to text_poke when arch not supported ftrace direct call
>    riscv, bpf: Factor out emit_call for kernel and bpf context
>    riscv, bpf: Add bpf_arch_text_poke support for RV64
>    riscv, bpf: Add bpf trampoline support for RV64
> 
>   arch/riscv/net/bpf_jit.h        |   5 +
>   arch/riscv/net/bpf_jit_comp64.c | 484 ++++++++++++++++++++++++++++++--
>   kernel/bpf/trampoline.c         |   8 +-
>   3 files changed, 472 insertions(+), 25 deletions(-)
> 

sorry, small problem of this patchset, have been resend.