From: Sven Schnelle <svens@stackframe.org>
To: Steven Price <steven.price@arm.com>
Cc: "Anshuman Khandual" <anshuman.khandual@arm.com>,
linux-mm@kvack.org, "Helge Deller" <deller@gmx.de>,
"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>,
linux-kernel@vger.kernel.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>,
"Will Deacon" <will@kernel.org>,
"Andrew Morton" <akpm@linux-foundation.org>,
linux-arm-kernel@lists.infradead.org, "Liang,
Kan" <kan.liang@linux.intel.com>
Subject: Re: [PATCH v9 00/21] Generic page walk and ptdump
Date: Wed, 31 Jul 2019 11:27:03 +0200 [thread overview]
Message-ID: <20190731092703.GA31316@t470p.stackframe.org> (raw)
In-Reply-To: <270ce719-49f9-7c61-8b25-bc9548a2f478@arm.com>
Hi Steven,
On Mon, Jul 29, 2019 at 12:32:25PM +0100, Steven Price wrote:
>
> parisc is more interesting and I'm not sure if this is necessarily
> correct. I originally proposed a patch with the line "For parisc, we
> don't support large pages, so add stubs returning 0" which got Acked by
> Helge Deller. However going back to look at that again I see there was a
> follow up thread[2] which possibly suggests I was wrong?
I just started a week ago implementing ptdump for PA-RISC. Didn't notice that
you're working on making it generic, which is nice. I'll adjust my code
to use the infrastructure you're currently developing.
> Can anyone shed some light on whether parisc does support leaf entries
> of the page table tree at a higher than the normal depth?
>
> [1] https://lkml.org/lkml/2019/2/27/572
> [2] https://lkml.org/lkml/2019/3/5/610
My understanding is that PA-RISC only has leaf entries on PTE level.
> The intention is that the page table walker would be available for all
> architectures so that it can be used in any generic code - PTDUMP simply
> seemed like a good place to start.
>
> > Now that pmd_leaf() and pud_leaf() are getting used in walk_page_range() these
> > functions need to be defined on all arch irrespective if they use PTDUMP or not
> > or otherwise just define it for archs which need them now for sure i.e x86 and
> > arm64 (which are moving to new generic PTDUMP framework). Other archs can
> > implement these later.
I'll take care of the PA-RISC part - for 32 bit your generic code works, for 64Bit
i need to learn a bit more about the following hack:
arch/parisc/include/asm/pgalloc.h:15
/* Allocate the top level pgd (page directory)
*
* Here (for 64 bit kernels) we implement a Hybrid L2/L3 scheme: we
* allocate the first pmd adjacent to the pgd. This means that we can
* subtract a constant offset to get to it. The pmd and pgd sizes are
* arranged so that a single pmd covers 4GB (giving a full 64-bit
* process access to 8TB) so our lookups are effectively L2 for the
* first 4GB of the kernel (i.e. for all ILP32 processes and all the
* kernel for machines with under 4GB of memory)
*/
I see that your change clear P?D entries when p?d_bad() returns true, which - i think -
would be the case with the PA-RISC implementation.
Regards
Sven
next prev parent reply other threads:[~2019-07-31 9:27 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-22 15:41 [PATCH v9 00/21] Generic page walk and ptdump Steven Price
2019-07-22 15:41 ` [PATCH v9 01/21] arc: mm: Add p?d_leaf() definitions Steven Price
2019-07-22 15:41 ` [PATCH v9 02/21] arm: " Steven Price
2019-07-22 15:41 ` [PATCH v9 03/21] arm64: " Steven Price
2019-07-22 15:41 ` [PATCH v9 04/21] mips: " Steven Price
2019-07-22 21:47 ` Paul Burton
2019-07-24 13:03 ` Steven Price
2019-07-22 15:41 ` [PATCH v9 05/21] powerpc: " Steven Price
2019-07-22 15:41 ` [PATCH v9 06/21] riscv: " Steven Price
2019-07-22 15:41 ` [PATCH v9 07/21] s390: " Steven Price
2019-07-22 15:41 ` [PATCH v9 08/21] sparc: " Steven Price
2019-07-22 15:41 ` [PATCH v9 09/21] x86: " Steven Price
2019-07-22 15:41 ` [PATCH v9 10/21] mm: Add generic p?d_leaf() macros Steven Price
2019-07-23 9:41 ` Mark Rutland
2019-07-24 13:48 ` Steven Price
2019-07-28 11:44 ` Anshuman Khandual
2019-07-29 11:38 ` Steven Price
2019-08-01 6:09 ` Anshuman Khandual
2019-08-01 12:22 ` Steven Price
2019-07-29 12:50 ` Mark Rutland
2019-08-01 6:13 ` Anshuman Khandual
2019-07-22 15:42 ` [PATCH v9 11/21] mm: pagewalk: Add p4d_entry() and pgd_entry() Steven Price
2019-07-23 10:14 ` Mark Rutland
2019-07-24 13:53 ` Steven Price
2019-07-24 14:09 ` Mark Rutland
2019-07-28 12:33 ` Anshuman Khandual
2019-07-29 12:17 ` Steven Price
2019-07-22 15:42 ` [PATCH v9 12/21] mm: pagewalk: Allow walking without vma Steven Price
2019-07-28 14:20 ` Anshuman Khandual
2019-07-29 12:29 ` Steven Price
2019-08-01 6:41 ` Anshuman Khandual
2019-07-22 15:42 ` [PATCH v9 13/21] mm: pagewalk: Add test_p?d callbacks Steven Price
2019-07-28 13:41 ` Anshuman Khandual
2019-07-29 12:34 ` Steven Price
2019-07-22 15:42 ` [PATCH v9 14/21] x86: mm: Don't display pages which aren't present in debugfs Steven Price
2019-07-22 15:42 ` [PATCH v9 15/21] x86: mm: Point to struct seq_file from struct pg_state Steven Price
2019-07-22 15:42 ` [PATCH v9 16/21] x86: mm+efi: Convert ptdump_walk_pgd_level() to take a mm_struct Steven Price
2019-07-22 15:42 ` [PATCH v9 17/21] x86: mm: Convert ptdump_walk_pgd_level_debugfs() to take an mm_struct Steven Price
2019-07-22 15:42 ` [PATCH v9 18/21] x86: mm: Convert ptdump_walk_pgd_level_core() " Steven Price
2019-07-22 15:42 ` [PATCH v9 19/21] mm: Add generic ptdump Steven Price
2019-07-23 9:57 ` Mark Rutland
2019-07-24 16:36 ` Steven Price
2019-07-29 2:59 ` Anshuman Khandual
2019-07-29 13:56 ` Steven Price
2019-07-22 15:42 ` [PATCH v9 20/21] x86: mm: Convert dump_pagetables to use walk_page_range Steven Price
2019-07-22 15:42 ` [PATCH v9 21/21] arm64: mm: Convert mm/dump.c to use walk_page_range() Steven Price
2019-07-23 6:39 ` [PATCH v9 00/21] Generic page walk and ptdump Anshuman Khandual
2019-07-24 13:35 ` Steven Price
2019-07-25 9:09 ` Anshuman Khandual
2019-07-25 9:30 ` Will Deacon
2019-07-26 6:03 ` Anshuman Khandual
2019-07-25 10:15 ` Steven Price
2019-07-23 10:16 ` Mark Rutland
2019-07-24 13:35 ` Steven Price
2019-07-24 13:57 ` Thomas Gleixner
2019-07-24 14:07 ` Mark Rutland
2019-07-24 14:18 ` Steven Price
2019-07-24 14:37 ` Thomas Gleixner
2019-07-28 11:20 ` Anshuman Khandual
2019-07-29 11:32 ` Steven Price
2019-07-31 9:27 ` Sven Schnelle [this message]
2019-07-31 11:18 ` Steven Price
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