linux-kernel - Re: [patch 16/16] x86/entry: Disable interrupts in IDTENTRY

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Message-ID: <87eeuhp0aw.fsf@nanos.tec.linutronix.de>
Date:   Wed, 26 Feb 2020 21:21:11 +0100
From:   Thomas Gleixner <tglx@...utronix.de>
To:     Peter Zijlstra <peterz@...radead.org>
Cc:     LKML <linux-kernel@...r.kernel.org>, x86@...nel.org,
        Steven Rostedt <rostedt@...dmis.org>,
        Brian Gerst <brgerst@...il.com>,
        Juergen Gross <jgross@...e.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Arnd Bergmann <arnd@...db.de>
Subject: Re: [patch 16/16] x86/entry: Disable interrupts in IDTENTRY

Peter Zijlstra <peterz@...radead.org> writes:

> On Tue, Feb 25, 2020 at 11:33:37PM +0100, Thomas Gleixner wrote:
>> Not all exceptions guarantee to return with interrupts disabled. Disable
>> them in idtentry_exit() which is invoked on all regular (non IST) exception
>> entry points. Preparatory patch for further consolidation of the return
>> code.
>
> ISTR a patch that undoes cond_local_irq_enable() in the various trap
> handlers. Did that get lost or is that still on the TODO list
> somewhere?

Hmm. I ditched it after we decided that fixing the #PF cases is ugly as
hell. Lemme find that stuff again.

> Once we do that, this can turn into an assertion that IRQs are in fact
> disabled.

Right.

Thanks,

        tglx