From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Steven Price <steven.price@arm.com>
Cc: "Mark Rutland" <Mark.Rutland@arm.com>,
x86@kernel.org, "Arnd Bergmann" <arnd@arndb.de>,
"Ard Biesheuvel" <ard.biesheuvel@linaro.org>,
"Peter Zijlstra" <peterz@infradead.org>,
"Catalin Marinas" <catalin.marinas@arm.com>,
"Dave Hansen" <dave.hansen@linux.intel.com>,
"Will Deacon" <will.deacon@arm.com>,
linux-kernel@vger.kernel.org,
"Russell King" <linux@armlinux.org.uk>,
linux-mm@kvack.org, "Jérôme Glisse" <jglisse@redhat.com>,
"Ingo Molnar" <mingo@redhat.com>,
"Borislav Petkov" <bp@alien8.de>,
"Andy Lutomirski" <luto@kernel.org>,
"H. Peter Anvin" <hpa@zytor.com>,
"James Morse" <james.morse@arm.com>,
"Thomas Gleixner" <tglx@linutronix.de>,
linux-arm-kernel@lists.infradead.org, "Liang,
Kan" <kan.liang@linux.intel.com>
Subject: Re: [PATCH v3 03/34] arm: mm: Add p?d_large() definitions
Date: Mon, 4 Mar 2019 16:10:54 +0300 [thread overview]
Message-ID: <20190304131054.goxpqsosolkg7khf@kshutemo-mobl1> (raw)
In-Reply-To: <974310a0-0114-9a0c-9041-4e0394c4b9aa@arm.com>
On Mon, Mar 04, 2019 at 11:56:13AM +0000, Steven Price wrote:
> On 01/03/2019 21:47, Kirill A. Shutemov wrote:
> > On Wed, Feb 27, 2019 at 05:05:37PM +0000, Steven Price wrote:
> >> walk_page_range() is going to be allowed to walk page tables other than
> >> those of user space. For this it needs to know when it has reached a
> >> 'leaf' entry in the page tables. This information will be provided by the
> >> p?d_large() functions/macros.
> >>
> >> For arm, we already provide most p?d_large() macros. Add a stub for PUD
> >> as we don't have huge pages at that level.
> >
> > We do not have PUD for 2- and 3-level paging. Macros from generic header
> > should cover it, shouldn't it?
> >
>
> I'm not sure of the reasoning behind this, but levels are folded in a
> slightly strange way. arm/include/asm/pgtable.h defines
> __ARCH_USE_5LEVEL_HACK which means:
>
> PGD has 2048 (2-level) or 4 (3-level) entries which are always
> considered 'present' (pgd_present() returns 1 defined in
> asm-generic/pgtables-nop4d-hack.h).
>
> P4D has 1 entry which is always present (see asm-generic/5level-fixup.h)
>
> PUD has 1 entry (see asm-generic/pgtable-nop4d-hack.h). This is always
> present for 2-level, and present only if the first level of real page
> table is present with a 3-level.
>
> PMD/PTE are as you might expect.
>
> So in terms of tables which are more than one entry you have PGD,
> (optionally) PMD, PTE. But the levels which actually read the table
> entries are PUD, PMD, PTE.
>
> This means that the corresponding p?d_large() macros are needed for
> PUD/PMD as that is where the actual entries are read. The asm-generic
> files provide the definitions for PGD/P4D.
Makes sense.
Only additional thing worth nothing that ARM in 2-level paging case folds
PMD manually without help from generic headres.
I'm partly responsible for the mess with folding. Sorry that you need to
explain this to :P
--
Kirill A. Shutemov
next prev parent reply other threads:[~2019-03-04 13:11 UTC|newest]
Thread overview: 68+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-27 17:05 [PATCH v3 00/34] Convert x86 & arm64 to use generic page walk Steven Price
2019-02-27 17:05 ` [PATCH v3 01/34] alpha: mm: Add p?d_large() definitions Steven Price
2019-02-27 17:05 ` [PATCH v3 02/34] arc: " Steven Price
2019-02-27 18:18 ` Vineet Gupta
2019-02-27 17:05 ` [PATCH v3 03/34] arm: " Steven Price
2019-03-01 21:47 ` Kirill A. Shutemov
2019-03-04 11:56 ` Steven Price
2019-03-04 13:10 ` Kirill A. Shutemov [this message]
2019-02-27 17:05 ` [PATCH v3 04/34] arm64: " Steven Price
2019-02-27 17:05 ` [PATCH v3 05/34] c6x: " Steven Price
2019-03-01 21:48 ` Kirill A. Shutemov
2019-03-04 12:01 ` Steven Price
2019-03-04 13:11 ` Kirill A. Shutemov
2019-02-27 17:05 ` [PATCH v3 06/34] csky: " Steven Price
2019-03-01 21:51 ` Kirill A. Shutemov
2019-02-27 17:05 ` [PATCH v3 07/34] hexagon: " Steven Price
2019-02-27 17:05 ` [PATCH v3 08/34] ia64: " Steven Price
2019-03-01 21:57 ` Kirill A. Shutemov
2019-03-04 13:16 ` Steven Price
2019-03-04 19:06 ` Luck, Tony
2019-03-06 13:45 ` Steven Price
2019-02-27 17:05 ` [PATCH v3 09/34] m68k: " Steven Price
2019-02-27 19:27 ` Geert Uytterhoeven
2019-02-28 11:36 ` Mike Rapoport
2019-02-28 11:53 ` Geert Uytterhoeven
2019-02-28 12:04 ` Steven Price
2019-03-01 11:45 ` Mike Rapoport
2019-02-27 17:05 ` [PATCH v3 10/34] microblaze: " Steven Price
2019-02-27 17:05 ` [PATCH v3 11/34] mips: " Steven Price
2019-02-28 2:15 ` Paul Burton
2019-02-28 12:11 ` Steven Price
2019-02-28 18:55 ` Paul Burton
2019-03-01 11:02 ` Steven Price
2019-02-27 17:05 ` [PATCH v3 12/34] nds32: " Steven Price
2019-02-27 17:05 ` [PATCH v3 13/34] nios2: " Steven Price
2019-02-27 17:05 ` [PATCH v3 14/34] openrisc: " Steven Price
2019-02-27 17:05 ` [PATCH v3 15/34] parisc: " Steven Price
2019-02-27 18:54 ` Helge Deller
2019-03-01 22:12 ` Kirill A. Shutemov
2019-03-05 21:45 ` Helge Deller
2019-02-27 17:05 ` [PATCH v3 16/34] powerpc: " Steven Price
2019-02-27 17:05 ` [PATCH v3 17/34] riscv: " Steven Price
2019-02-27 17:05 ` [PATCH v3 18/34] s390: " Steven Price
2019-02-27 17:40 ` Martin Schwidefsky
2019-02-28 11:43 ` Steven Price
2019-02-27 17:05 ` [PATCH v3 19/34] sh: " Steven Price
2019-02-27 17:05 ` [PATCH v3 20/34] sparc: " Steven Price
2019-02-27 18:38 ` David Miller
2019-02-28 11:49 ` Steven Price
2019-02-27 17:05 ` [PATCH v3 21/34] um: " Steven Price
2019-02-27 17:05 ` [PATCH v3 22/34] unicore32: " Steven Price
2019-02-27 17:05 ` [PATCH v3 23/34] xtensa: " Steven Price
2019-02-27 17:29 ` Max Filippov
2019-02-27 17:05 ` [PATCH v3 24/34] mm: Add generic p?d_large() macros Steven Price
2019-02-27 17:05 ` [PATCH v3 25/34] mm: pagewalk: Add p4d_entry() and pgd_entry() Steven Price
2019-02-27 17:06 ` [PATCH v3 26/34] mm: pagewalk: Allow walking without vma Steven Price
2019-02-27 17:06 ` [PATCH v3 27/34] mm: pagewalk: Add 'depth' parameter to pte_hole Steven Price
2019-02-27 17:38 ` Dave Hansen
2019-02-28 11:28 ` Steven Price
2019-02-28 19:00 ` Dave Hansen
2019-03-01 11:24 ` Steven Price
2019-02-27 17:06 ` [PATCH v3 28/34] mm: pagewalk: Add test_p?d callbacks Steven Price
2019-02-27 17:06 ` [PATCH v3 29/34] arm64: mm: Convert mm/dump.c to use walk_page_range() Steven Price
2019-02-27 17:06 ` [PATCH v3 30/34] x86/mm: Point to struct seq_file from struct pg_state Steven Price
2019-02-27 17:06 ` [PATCH v3 31/34] x86/mm+efi: Convert ptdump_walk_pgd_level() to take a mm_struct Steven Price
2019-02-27 17:06 ` [PATCH v3 32/34] x86/mm: Convert ptdump_walk_pgd_level_debugfs() to take an mm_struct Steven Price
2019-02-27 17:06 ` [PATCH v3 33/34] x86/mm: Convert ptdump_walk_pgd_level_core() " Steven Price
2019-02-27 17:06 ` [PATCH v3 34/34] x86: mm: Convert dump_pagetables to use walk_page_range Steven Price
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=20190304131054.goxpqsosolkg7khf@kshutemo-mobl1 \
--to=kirill@shutemov.name \
--cc=Mark.Rutland@arm.com \
--cc=ard.biesheuvel@linaro.org \
--cc=arnd@arndb.de \
--cc=bp@alien8.de \
--cc=catalin.marinas@arm.com \
--cc=dave.hansen@linux.intel.com \
--cc=hpa@zytor.com \
--cc=james.morse@arm.com \
--cc=jglisse@redhat.com \
--cc=kan.liang@linux.intel.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=linux@armlinux.org.uk \
--cc=luto@kernel.org \
--cc=mingo@redhat.com \
--cc=peterz@infradead.org \
--cc=steven.price@arm.com \
--cc=tglx@linutronix.de \
--cc=will.deacon@arm.com \
--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).