linux-kernel - Re: [PATCH 3/8] x86/mm: Define virtual memory map for 5-level paging

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Message-ID: <20170328224720.7ir7godugb6eqzm5@node.shutemov.name>
Date:   Wed, 29 Mar 2017 01:47:20 +0300
From:   "Kirill A. Shutemov" <kirill@...temov.name>
To:     "H. Peter Anvin" <hpa@...or.com>
Cc:     "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Andrew Morton <akpm@...ux-foundation.org>, x86@...nel.org,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        Andi Kleen <ak@...ux.intel.com>,
        Dave Hansen <dave.hansen@...el.com>,
        Andy Lutomirski <luto@...capital.net>,
        linux-arch@...r.kernel.org, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 3/8] x86/mm: Define virtual memory map for 5-level paging

On Tue, Mar 28, 2017 at 03:21:39PM -0700, H. Peter Anvin wrote:
> On 03/27/17 09:29, Kirill A. Shutemov wrote:
> > +fffe000000000000 - fffe007fffffffff (=39 bits) %esp fixup stacks
> 
> Why move this?

You're right. There's no reason to.

It's accident due to ESPFIX_BASE_ADDR being defined using PGDIR_SHIFT.
We should use P4D_SHIFT instead to produce consistent result across
paging modes.

I'll update the patch tomorrow. Thanks for noticing this.

-- 
 Kirill A. Shutemov