From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: linux-mm@kvack.org, Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
"H. Peter Anvin" <hpa@zytor.com>,
Dave Hansen <dave.hansen@intel.com>,
Andrew Morton <akpm@linux-foundation.org>,
x86@kernel.org, linux-kernel@vger.kernel.org,
Dan Williams <dan.j.williams@intel.com>
Subject: Re: [PATCH] x86/mm: Make pud_present() check _PAGE_PROTNONE and _PAGE_PSE as well
Date: Fri, 20 Mar 2020 14:47:41 +0300 [thread overview]
Message-ID: <20200320114741.c62iolt2yzltnscf@box> (raw)
In-Reply-To: <c03165c8-6d44-49c2-2dad-a85759200718@arm.com>
On Fri, Mar 20, 2020 at 08:53:16AM +0530, Anshuman Khandual wrote:
>
>
> On 03/18/2020 10:31 AM, Anshuman Khandual wrote:
> > pud_present() should also check _PAGE_PROTNONE and _PAGE_PSE bits like in
> > case pmd_present(). This makes a PUD entry test positive for pud_present()
> > after getting invalidated with pud_mknotpresent(), hence standardizing the
> > semantics with PMD helpers.
> >
> > Cc: Thomas Gleixner <tglx@linutronix.de>
> > Cc: Ingo Molnar <mingo@redhat.com>
> > Cc: Borislav Petkov <bp@alien8.de>
> > Cc: "H. Peter Anvin" <hpa@zytor.com>
> > Cc: Dave Hansen <dave.hansen@intel.com>
> > Cc: Andrew Morton <akpm@linux-foundation.org>
> > Cc: x86@kernel.org
> > Cc: linux-mm@kvack.org
> > Cc: linux-kernel@vger.kernel.org
> > Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
> > ---
> > Even though pud_mknotpresent() is not used any where currently, there is
> > a discrepancy between PMD and PUD.
> >
> > WARN_ON(!pud_present(pud_mknotpresent(pud_mkhuge(pud)))) -> Fail
> > WARN_ON(!pmd_present(pmd_mknotpresent(pmd_mkhuge(pmd)))) -> Pass
> >
> > Though pud_mknotpresent() currently clears _PAGE_PROTNONE, pud_present()
> > does not check it. This change fixes both inconsistencies.
> >
> > This has been build and boot tested on x86.
>
> Adding Kirill and Dan.
>
> +Cc: Kirill A. Shutemov <kirill@shutemov.name>
> +Cc: Dan Williams <dan.j.williams@intel.com>
Or we can just drop the pud_mknotpresent(). There's no users AFAICS and
only x86 provides it.
--
Kirill A. Shutemov
next prev parent reply other threads:[~2020-03-20 11:47 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-18 5:01 [PATCH] x86/mm: Make pud_present() check _PAGE_PROTNONE and _PAGE_PSE as well Anshuman Khandual
2020-03-20 3:23 ` Anshuman Khandual
2020-03-20 11:47 ` Kirill A. Shutemov [this message]
2020-03-20 13:22 ` Anshuman Khandual
2020-03-20 19:50 ` John Hubbard
2020-03-22 1:00 ` Anshuman Khandual
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200320114741.c62iolt2yzltnscf@box \
--to=kirill@shutemov.name \
--cc=akpm@linux-foundation.org \
--cc=anshuman.khandual@arm.com \
--cc=bp@alien8.de \
--cc=dan.j.williams@intel.com \
--cc=dave.hansen@intel.com \
--cc=hpa@zytor.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mingo@redhat.com \
--cc=tglx@linutronix.de \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).