From: Andrew Morton <akpm@linux-foundation.org>
To: Peter Collingbourne <pcc@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>,
Alexander Potapenko <glider@google.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Vincenzo Frascino <vincenzo.frascino@arm.com>,
Jann Horn <jannh@google.com>,
Evgenii Stepanov <eugenis@google.com>,
linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v6 0/4] arm64: improve efficiency of setting tags for user pages
Date: Thu, 3 Jun 2021 20:03:08 -0700 [thread overview]
Message-ID: <20210603200308.2a08d25db0dc92430a545b4c@linux-foundation.org> (raw)
In-Reply-To: <20210602235230.3928842-1-pcc@google.com>
On Wed, 2 Jun 2021 16:52:26 -0700 Peter Collingbourne <pcc@google.com> wrote:
> Currently we can end up touching PROT_MTE user pages twice on fault
> and once on unmap. On fault, with KASAN disabled we first clear data
> and then set tags to 0, and with KASAN enabled we simultaneously
> clear data and set tags to the KASAN random tag, and then set tags
> again to 0. On unmap, we poison the page by setting tags, but this
> is less likely to find a bug than poisoning kernel pages.
>
> This patch series fixes these inefficiencies by only touching the pages
> once on fault using the DC GZVA instruction to clear both data and
> tags, and avoiding poisoning user pages on free.
>
> ...
>
> arch/alpha/include/asm/page.h | 6 +--
> arch/arm64/include/asm/mte.h | 4 ++
> arch/arm64/include/asm/page.h | 10 +++--
> arch/arm64/lib/mte.S | 20 ++++++++++
> arch/arm64/mm/fault.c | 26 +++++++++++++
> arch/arm64/mm/proc.S | 10 +++--
> arch/ia64/include/asm/page.h | 6 +--
> arch/m68k/include/asm/page_no.h | 6 +--
> arch/s390/include/asm/page.h | 6 +--
> arch/x86/include/asm/page.h | 6 +--
> include/linux/gfp.h | 18 +++++++--
> include/linux/highmem.h | 43 ++++++++-------------
> include/linux/kasan.h | 64 +++++++++++++++++++-------------
> include/linux/page-flags.h | 9 +++++
> include/trace/events/mmflags.h | 9 ++++-
> mm/kasan/common.c | 4 +-
> mm/kasan/hw_tags.c | 32 ++++++++++++++++
> mm/mempool.c | 6 ++-
> mm/page_alloc.c | 66 +++++++++++++++++++--------------
> 19 files changed, 242 insertions(+), 109 deletions(-)
This is more MMish than ARMish, but I expect it will get more exposure
in an ARM tree than in linux-next alone.
I'll grab them for now, but in the hope that they will appear in -next
via an ARM tree so I get to drop them again.
next prev parent reply other threads:[~2021-06-04 3:03 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-02 23:52 Peter Collingbourne
2021-06-02 23:52 ` [PATCH v6 1/4] mm: arch: remove indirection level in alloc_zeroed_user_highpage_movable() Peter Collingbourne
2021-06-04 9:45 ` Catalin Marinas
2021-06-02 23:52 ` [PATCH v6 2/4] kasan: use separate (un)poison implementation for integrated init Peter Collingbourne
2021-06-02 23:52 ` [PATCH v6 3/4] arm64: mte: handle tags zeroing at page allocation time Peter Collingbourne
2021-06-02 23:52 ` [PATCH v6 4/4] kasan: disable freed user page poisoning with HW tags Peter Collingbourne
2021-06-04 3:03 ` Andrew Morton [this message]
2021-06-04 18:31 ` [PATCH v6 0/4] arm64: improve efficiency of setting tags for user pages Will Deacon
2021-06-04 19:48 ` Will Deacon
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=20210603200308.2a08d25db0dc92430a545b4c@linux-foundation.org \
--to=akpm@linux-foundation.org \
--cc=andreyknvl@gmail.com \
--cc=catalin.marinas@arm.com \
--cc=eugenis@google.com \
--cc=glider@google.com \
--cc=jannh@google.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-mm@kvack.org \
--cc=pcc@google.com \
--cc=vincenzo.frascino@arm.com \
/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