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Date:   Tue, 6 Nov 2018 17:49:07 +0100 (CET)
From:   Miroslav Benes <mbenes@suse.cz>
To:     Torsten Duwe <duwe@lst.de>
cc:     Will Deacon <will.deacon@arm.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Julien Thierry <julien.thierry@arm.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Josh Poimboeuf <jpoimboe@redhat.com>,
        Ingo Molnar <mingo@redhat.com>,
        Ard Biesheuvel <ard.biesheuvel@linaro.org>,
        Arnd Bergmann <arnd@arndb.de>,
        AKASHI Takahiro <takahiro.akashi@linaro.org>,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        live-patching@vger.kernel.org
Subject: Re: [PATCH v4 2/3] arm64: implement live patching
In-Reply-To: <20181026142152.5F0D868C95@newverein.lst.de>
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References: <20181026142008.D922868C94@newverein.lst.de> <20181026142152.5F0D868C95@newverein.lst.de>
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Hi,

On Fri, 26 Oct 2018, Torsten Duwe wrote:

> Based on ftrace with regs, do the usual thing.
> (see Documentation/livepatch/livepatch.txt)
> 
> Use task flag bit 6 to track patch transisiton state for the consistency
> model. Add it to the work mask so it gets cleared on all kernel exits to
> userland.
> 
> Tell livepatch regs->pc is the place to change the return address.
> Make sure the graph tracer call hook is only called on the final function
> entry in case regs->pc gets modified after an interception.
> 
> Signed-off-by: Torsten Duwe <duwe@suse.de>

It looks good now apart from arm64 asm part which should be reviewed by 
someone else.

However, could you summarize our analysis regarding post-module-load calls 
of apply_relocate_add() in the commit log, please? It is important for 
future reference.

Thanks,
Miroslav