linux-kernel - Re: [PATCH] Fix resume on x86-32 machines

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Message-ID: <20171211151314.c3ip654ww4eghfpp@gmail.com>
Date:   Mon, 11 Dec 2017 16:13:14 +0100
From:   Ingo Molnar <mingo@...nel.org>
To:     Andy Lutomirski <luto@...capital.net>
Cc:     Pavel Machek <pavel@....cz>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Zhang Rui <rui.zhang@...el.com>,
        Andrew Lutomirski <luto@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Jarkko Nikula <jarkko.nikula@...ux.intel.com>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        the arch/x86 maintainers <x86@...nel.org>
Subject: Re: [PATCH] Fix resume on x86-32 machines


* Andy Lutomirski <luto@...capital.net> wrote:

> 
> 
> > On Dec 10, 2017, at 1:38 PM, Pavel Machek <pavel@....cz> wrote:
> > 
> > 
> > After 4.15-rc2, suspend stopped working on Thinkpad X60. 5b06bbc
> > (unintentionally?) reordered stuff with respect to
> > fix_processor_context() on 32-bit and 64-bit. We undo that change on
> > 32-bit.
> > 
> 
> Can you explain what was wrong with the reordering?  Your patch certainly *looks* incorrect.
> 
> I'm guessing that the real issue is that 32-bit needs %fs restored early for TLS.

Does some early percpu primitive need GS as well perhaps?

Might be safest to restore both FS and GS early.

Thanks,

	Ingo