Re: [PATCH] reduce the time of finding symbols for module

[Ruslan Bilovol]

Hi,

On 10/13/2017 04:18 PM, Torsten Duwe wrote:
> On Fri, Oct 13, 2017 at 03:54:46PM +0300, Ruslan Bilovol wrote:
> > Hi Li,
> >
> > On Wed, Mar 29, 2017 at 4:50 AM, Li Bin <huawei.libin@xxxxxxxxxx> wrote:
> > > Hi,
> > [snip]
> > > Yeah, from 2014, we started to work on livepatch support on aarch64, and
> > > in May 2015, we pushed the solution to the livepatch community[1] and gcc
> > > community (mfentry feature on aarch64)[2]. And then, there were an another
> > > gcc solution from linaro [3], which proposes to implement a new option
> > > -fprolog-pad=N that generate a pad of N nops at the beginning of each
> > > function, and AFAIK, Torsten Duwe from SUSE is still discussing this method
> > > with gcc community.
> > >
> > > At this stage, we are validating the livepatch support on aarch64 based on
> > > aarch64 mfentry feature. When the community has a clear plan, we are happy
> > > to make adaptation and contribute our related work to the community, including
> > > the kpatch-build support :-)
> > >
> > > [1] livepatch: add support on arm64
> > > https://lkml.org/lkml/2015/5/28/54
> > > [2] [AArch64] support -mfentry feature for arm64
> > > https://gcc.gnu.org/ml/gcc-patches/2016-03/msg00756.html
> > > [3] Kernel livepatching support in GCC
> > > https://gcc.gnu.org/ml/gcc/2015-05/msg00267.html
> > > [4] arm64: ftrace with regs for livepatch support
> > > http://lists.infradead.org/pipermail/linux-arm-kernel/2016-January/401352.html
> >
> > Since there is already -fpatchable-function-entry option committed by Torsten
> > to gcc on 25 Jul [1], have you restarted your activities with AArch64 livepatch
> > support?
> > If yes, I'm interested in testing of that feature/patches on our hardware
>
> I also have the coresponding kernel patch(es) here. IIRC I already sent
> tham to LKML. I'll re-send them once there are more gcc's with -fpatchable-function-entry
> support out there.

Do you mean "[PATCH v3 0/2] arm64 live patching" [1] series?

I'm going to play with them and see how it works.

Another question: have you tested livepatching on Big Endian systems?

[1] https://lwn.net/Articles/697050

Thanks,
Ruslan