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Re: Any future plan supporting livepatching in kernel for AArch64?
- From: "Bin.Cheng" <amker dot cheng at gmail dot com>
- To: Andrew Pinski <pinskia at gmail dot com>
- Cc: GCC Development <gcc at gcc dot gnu dot org>, Maxim Kuvyrkov <maxim dot kuvyrkov at linaro dot org>, Li Bin <huawei dot libin at huawei dot com>, duwe at suse dot de, Szabolcs Nagy <szabolcs dot nagy at arm dot com>, Richard Earnshaw <rearnsha at arm dot com>, "takahiro dot akashi at linaro dot org" <takahiro dot akashi at linaro dot org>
- Date: Thu, 19 Sep 2019 13:17:13 +0800
- Subject: Re: Any future plan supporting livepatching in kernel for AArch64?
- References: <CAHFci29qcCB1=KvXzXDx5vJJ0gryBVMpv0Tz+6aB0JGx6er4Fg@mail.gmail.com> <CA+=Sn1kjVqabCzyEXLeFDdBh6gFBKBgvdv6xPwBbYQS1KUbXDw@mail.gmail.com> <CA+=Sn1m4e+vr-XgTHRUXoys2b4Cr3TmLy-qU_P-LUd9q_h28OQ@mail.gmail.com>
On Thu, Sep 19, 2019 at 1:02 PM Andrew Pinski <email@example.com> wrote:
> On Wed, Sep 18, 2019 at 9:56 PM Andrew Pinski <firstname.lastname@example.org> wrote:
> > On Wed, Sep 18, 2019 at 9:24 PM Bin.Cheng <email@example.com> wrote:
> > >
> > > Hi,
> > > I read through previous messages which tried to support livepatching
> > > in kernel for AArch64.
> > > Following is the patch supporting mfentry:
> > > https://gcc.gnu.org/ml/gcc-patches/2016-03/msg00756.html
> > > And this is the last message about above thread:
> > > https://gcc.gnu.org/ml/gcc-patches/2016-04/msg01093.html
> > >
> > > Here is another patch trying to support a general option, however. it
> > > was not merged either.
> > > https://gcc.gnu.org/ml/gcc-patches/2016-12/msg01791.html
> > >
> > > If I read messages correctly, kernel part is not merged (partly)
> > > because of waiting for GCC. As a result, we have to apply local
> > > patches, I am wondering if there is any future plan to support it on
> > > AArch64, or no one really uses it?
> > A GCC patch was merged for this already and is included in GCC 9.1.0 and above.
> > See https://gcc.gnu.org/onlinedocs/gcc-9.2.0/gcc/Common-Function-Attributes.html#index-patchable_005ffunction_005fentry-function-attribute
> > And
> > https://gcc.gnu.org/onlinedocs/gcc-9.2.0/gcc/Instrumentation-Options.html#index-fpatchable-function-entry
> > Someone did not add it to the GCC 9 release notes though to highlight it.
> Note I Mean GCC 8 release notes as it was included in GCC 8.1.0 and above :).
> Also see https://lkml.org/lkml/2017/10/13/340 for the Linux side of
> discussion about this option :).
Thank you very much, the option name changed several times and I
missed this one!
> > Thanks,
> > Andrew Pinski
> > >
> > > I CCed patch authors as well as who joined previous discussions,
> > > please let me know if you don't want to be cced in this thread.
> > >
> > > Thanks,
> > > bin