2022-04-16 00:27:50

by Andrii Nakryiko

[permalink] [raw]
Subject: Re: [PATCH bpf-next v2 5/6] bpf, arm64: bpf trampoline for arm64

On Thu, Apr 14, 2022 at 9:10 AM Xu Kuohai <[email protected]> wrote:
>
> Add bpf trampoline support for arm64. Most of the logic is the same as
> x86.
>
> fentry before bpf trampoline hooked:
> mov x9, x30
> nop
>
> fentry after bpf trampoline hooked:
> mov x9, x30
> bl <bpf_trampoline>
>
> Tested on qemu, result:
> #55 fentry_fexit:OK
> #56 fentry_test:OK
> #58 fexit_sleep:OK
> #59 fexit_stress:OK
> #60 fexit_test:OK
> #67 get_func_args_test:OK
> #68 get_func_ip_test:OK
> #101 modify_return:OK
>
> Signed-off-by: Xu Kuohai <[email protected]>
> Acked-by: Song Liu <[email protected]>
> ---

Can you please also take a look at [0], which is an ongoing work to
add support for BPF cookie to BPF trampoline-based BPF programs. It's
very close to being done, so it would be good if you can implement
that at the same time.

[0] https://patchwork.kernel.org/project/netdevbpf/patch/[email protected]/

> arch/arm64/net/bpf_jit.h | 14 +-
> arch/arm64/net/bpf_jit_comp.c | 338 +++++++++++++++++++++++++++++++++-
> 2 files changed, 348 insertions(+), 4 deletions(-)
>

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