linux-kernel - Re: [PATCH] ARM: initialize jump labels before setup_machine

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Message-ID: <CAHmME9o0+qC+qrCBoWp=FLcVABYrO+Bcihu_oWWaGJ3XuthseA@mail.gmail.com>
Date:   Fri, 3 Jun 2022 10:12:44 +0200
From:   "Jason A. Donenfeld" <Jason@...c4.com>
To:     Ard Biesheuvel <ardb@...nel.org>
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Russell King <linux@...linux.org.uk>,
        Russell King <rmk+kernel@...linux.org.uk>,
        Linux ARM <linux-arm-kernel@...ts.infradead.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Catalin Marinas <catalin.marinas@....com>,
        Stephen Boyd <swboyd@...omium.org>,
        "# 3.4.x" <stable@...r.kernel.org>
Subject: Re: [PATCH] ARM: initialize jump labels before setup_machine_fdt()

Hi Ard,

On 6/3/22, Ard Biesheuvel <ardb@...nel.org> wrote:
> The problem is that your original patch

You remain extremely unpleasant to communicate with. Can we keep
things on topic please?

> As far as I can tell, the early patching code on ARM does not rely on
> the early fixmap code. Did you try just moving jump_label_init()
> earlier in the function?
>
> Also, how did you test this change?

Just booting a few configs in QEMU. I don't have access to real
hardware right now unfortunately.

Let me give a try to just moving the jump_label_init() function alone.
That'd certainly make this patch a lot more basic, which would be a
good thing, and might assuage your well justified concerns that too
much boot order churn will break something subtle. I was just afraid
of complicated intermingling with the other stuff after I saw that
arm64 did things in the other order. But maybe that's silly.

I'll send a v2 if that works, and send an update here if it doesn't.
Thanks for the suggestion.

Jason