* bpf helper functions from kernel module
@ 2021-04-22 15:43 Kenny Ho
2021-04-22 16:43 ` Toke Høiland-Jørgensen
0 siblings, 1 reply; 3+ messages in thread
From: Kenny Ho @ 2021-04-22 15:43 UTC (permalink / raw)
To: bpf
Hi,
From https://www.collabora.com/news-and-blog/blog/2019/04/15/an-ebpf-overview-part-2-machine-and-bytecode/
"The BPF-accesible kernel "helper" functions are defined by the kernel
core (not extensible through modules) via an API similar to defining
syscalls"
Has there been interest/discussion around having helper functions from
kernel modules? Going through the code, I am guessing one of the
obstacles is to have the verifier checking against helper functions
that may or may not be available but I am not an expert of the
subsystem. What are the current opinions on having helper functions
from kernel modules?
Regards,
Kenny Ho
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: bpf helper functions from kernel module
2021-04-22 15:43 bpf helper functions from kernel module Kenny Ho
@ 2021-04-22 16:43 ` Toke Høiland-Jørgensen
2021-04-23 13:41 ` Kenny Ho
0 siblings, 1 reply; 3+ messages in thread
From: Toke Høiland-Jørgensen @ 2021-04-22 16:43 UTC (permalink / raw)
To: Kenny Ho, bpf
Kenny Ho <y2kenny@gmail.com> writes:
> Hi,
>
> From https://www.collabora.com/news-and-blog/blog/2019/04/15/an-ebpf-overview-part-2-machine-and-bytecode/
> "The BPF-accesible kernel "helper" functions are defined by the kernel
> core (not extensible through modules) via an API similar to defining
> syscalls"
>
> Has there been interest/discussion around having helper functions from
> kernel modules? Going through the code, I am guessing one of the
> obstacles is to have the verifier checking against helper functions
> that may or may not be available but I am not an expert of the
> subsystem. What are the current opinions on having helper functions
> from kernel modules?
The support for calling kernel functions directly (AKA "unstable
helpers") will likely be the way this will be achievable. See the
comment in brackets half-way down in the description here:
https://lore.kernel.org/bpf/20210325015142.1544736-1-kafai@fb.com/
-Toke
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: bpf helper functions from kernel module
2021-04-22 16:43 ` Toke Høiland-Jørgensen
@ 2021-04-23 13:41 ` Kenny Ho
0 siblings, 0 replies; 3+ messages in thread
From: Kenny Ho @ 2021-04-23 13:41 UTC (permalink / raw)
To: Toke Høiland-Jørgensen; +Cc: bpf
On Thu, Apr 22, 2021 at 12:43 PM Toke Høiland-Jørgensen <toke@redhat.com> wrote:
>
> The support for calling kernel functions directly (AKA "unstable
> helpers") will likely be the way this will be achievable. See the
> comment in brackets half-way down in the description here:
>
> https://lore.kernel.org/bpf/20210325015142.1544736-1-kafai@fb.com/
Oh this is very cool, I will look into it. Thanks for the pointer.
Regards,
Kenny
^ permalink raw reply [flat|nested] 3+ messages in thread
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