linux-kernel - Re: [PATCH 0/6] x86-64: Remove global variables from boot

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Date:   Thu, 23 Feb 2023 13:44:53 +0000
From:   David Woodhouse <dwmw2@...radead.org>
To:     Brian Gerst <brgerst@...il.com>, linux-kernel@...r.kernel.org,
        x86@...nel.org
Cc:     Usama Arif <usama.arif@...edance.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Borislav Petkov <bp@...en8.de>,
        "H . Peter Anvin" <hpa@...or.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Andy Lutomirski <luto@...nel.org>,
        Ingo Molnar <mingo@...nel.org>
Subject: Re: [PATCH 0/6] x86-64: Remove global variables from boot

On Wed, 2023-02-22 at 17:12 -0500, Brian Gerst wrote:
> This is on top of the parallel boot v10 series.
> 
> Remove the global variables initial_gs, initial_stack, and
> early_gdt_descr from the 64-bit boot code.  The stack, GDT, and GSBASE
> can be determined from the CPU number.
> 
> Brian Gerst (6):
>   x86/smpboot: Use CPU number instead of APIC ID for single CPU startup
>   x86/smpboot: Use current_task to get idle thread


I think those first two should be folded into the 'x86/smpboot: Support
parallel startup of secondary CPUs' patch rather than follow-on
patches?

>   x86/smpboot: Remove initial_stack on 64-bit
>   x86/smpbppt: Remove early_gdt_descr on 64-bit
>   x86/smpboot: Remove initial_gs
>   x86/smpboot: Simplify boot CPU setup

Those four probably make sense to come separately. For each of them,

Reviewed-by: David Woodhouse <dwmw@...zon.co.uk>

I've pulled in the v10 series from Usama, squashed the first two as I
suggested, added the last four on top to do some testing:
https://git.infradead.org/users/dwmw2/linux.git/shortlog/refs/heads/parallel-6.2-rc8-part1

Rather than overthinking the SoB chain, I've left Usama's signoff as
the last on the original series, and on the assumption that Usama will
continue posting, I'll give them the choice of my R-b or S-o-B on what
are now the final four.

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