[PATCH] powerpc64/bpf: support direct_call on livepatch function

[Naveen N Rao]

On Mon, Oct 06, 2025 at 06:50:20PM +0530, Hari Bathini wrote:
> 
> 
> On 06/10/25 1:22 pm, Naveen N Rao wrote:
> > On Fri, Oct 03, 2025 at 12:57:54AM +0530, Hari Bathini wrote:
> > > Today, livepatch takes precedence over direct_call. Instead, save the
> > > state and make direct_call before handling livepatch.
> > 
> > If we call into the BPF trampoline first and if we have
> > BPF_TRAMP_F_CALL_ORIG set, does this result in the BPF trampoline
> > calling the new copy of the live-patched function or the old one?
> 
> Naveen, calls the new copy of the live-patched function..

Hmm... I'm probably missing something.

With ftrace OOL stubs, what I recall is that BPF trampoline derives the 
original function address from the OOL stub (which would be associated 
with the original function, not the livepatch one). This should mean 
that the trampoline continues to invoke the original function.


- Naveen