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    SubjectRE: [PATCH v1] ARM: A9: Add ARM ERRATA 764319 workaround
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    On Tue, May 10, 2022 at 1:53 PM Verdun, Jean-Marie <verdun@hpe.com> wrote:
    > >
    > > Hi Arnd,
    > >
    > > > Hi Nick,
    > >
    > > > This seems a bit more complex than necessary. Can't you just use a custom
    > > inline asm with an ex_table entry to catch the fault? Have a look at
    > > __get_user_asm() for an example.
    > >
    > > Arnd
    > >
    > > We got inspired from debug_reg_hook within the same source file (
    > >./arch/arm/kernel/hw_breakpoint.c ). We chose that path to keep
    > >coherency within the source code. We can implement the same fix by
    > >using an ex_table entry, but this will create two different ways at
    > >catching unknown instruction within the same source file. Will that be ok ?

    > I got a little lost trying to find where the breakpoint instruction comes from that gets trapped here, but I would guess that they had to do this using an undef_hook because the ex_table approach does not work there for some reason.

    > I would still pick the ex_table method here if that works.

    I will pursue the method you have recommended Arnd.

    Thank you for the feedback as always.

    -Nick Hawkins
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