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Date:   Tue, 17 Jul 2018 09:07:25 +0200
From:   Joerg Roedel <jroedel@suse.de>
To:     Andy Lutomirski <luto@amacapital.net>
Cc:     Joerg Roedel <joro@8bytes.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@kernel.org>,
        "H . Peter Anvin" <hpa@zytor.com>, X86 ML <x86@kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Linux-MM <linux-mm@kvack.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Andy Lutomirski <luto@kernel.org>,
        Dave Hansen <dave.hansen@intel.com>,
        Josh Poimboeuf <jpoimboe@redhat.com>,
        Juergen Gross <jgross@suse.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Borislav Petkov <bp@alien8.de>, Jiri Kosina <jkosina@suse.cz>,
        Boris Ostrovsky <boris.ostrovsky@oracle.com>,
        Brian Gerst <brgerst@gmail.com>,
        David Laight <David.Laight@aculab.com>,
        Denys Vlasenko <dvlasenk@redhat.com>,
        Eduardo Valentin <eduval@amazon.com>,
        Greg KH <gregkh@linuxfoundation.org>,
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        Andrea Arcangeli <aarcange@redhat.com>,
        Waiman Long <llong@redhat.com>, Pavel Machek <pavel@ucw.cz>,
        "David H . Gutteridge" <dhgutteridge@sympatico.ca>
Subject: Re: [PATCH 07/39] x86/entry/32: Enter the kernel via trampoline stack
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On Fri, Jul 13, 2018 at 10:21:39AM -0700, Andy Lutomirski wrote:
> On Fri, Jul 13, 2018 at 3:56 AM, Joerg Roedel <joro@8bytes.org> wrote:
> > Right, I implement a more restrictive check.
> 
> But the check needs to be correct or we'll mess up, right?  I think
> the code will be much more robust and easier to review if you check
> "on the entry stack" instead of ">= the entry stack".  (Or <= -- I can
> never remember how this works in AT&T syntax.)

Yeah, I re-used the check implemented on the NMI entry path, it checks
exactly for the entry-stack range.


Regards,

	Joerg