From: Christian Borntraeger <borntraeger@de.ibm.com>
To: linux-kernel@vger.kernel.org
Cc: linux-arch@vger.kernel.org, paulmck@linux.vnet.ibm.com,
torvalds@linux-foundation.org
Subject: Re: [PATCHv4 0/9] ACCESS_ONCE and non-scalar accesses
Date: Thu, 04 Dec 2014 16:24:02 +0100 [thread overview]
Message-ID: <54807C92.1010405@de.ibm.com> (raw)
In-Reply-To: <1417645821-54731-1-git-send-email-borntraeger@de.ibm.com>
Am 03.12.2014 um 23:30 schrieb Christian Borntraeger:
> As discussed on LKML http://marc.info/?i=54611D86.4040306%40de.ibm.com
> ACCESS_ONCE might fail with specific compiler for non-scalar accesses.
>
> Here is a set of patches to tackle that problem.
>
> The first patch introduce READ_ONCE and ASSIGN_ONCE. If the data structure
> is larger than the machine word size memcpy is used and a warning is emitted.
> The next patches fix up all in-tree users of ACCESS_ONCE on non-scalar types.
> The last patch forces ACCESS_ONCE to work only on scalar types.
>
> I have cross-compiled the resulting kernel with defconfig and gcc 4.9 for
> microblaze, m68k, alpha, s390,x86_64, i686, sparc, sparc64, mips,
> ia64, arm and arm64.
>
> Runtime tested on s390x and x86_64. I have also verified that ASSIGN_ONCE works
> as expected with some test changes as there are no user in this patch series.
>
> Linus, ok for the next merge window?
>
> Christian Borntraeger (9):
> kernel: Provide READ_ONCE and ASSIGN_ONCE
> mm: replace ACCESS_ONCE with READ_ONCE or barriers
> x86/spinlock: Replace ACCESS_ONCE with READ_ONCE
> x86/gup: Replace ACCESS_ONCE with READ_ONCE
> mips/gup: Replace ACCESS_ONCE with READ_ONCE
> arm64/spinlock: Replace ACCESS_ONCE READ_ONCE
> arm/spinlock: Replace ACCESS_ONCE with READ_ONCE
> s390/kvm: REPLACE ACCESS_ONCE with READ_ONCE
> kernel: tighten rules for ACCESS ONCE
>
> arch/arm/include/asm/spinlock.h | 4 +--
> arch/arm64/include/asm/spinlock.h | 4 +--
> arch/mips/mm/gup.c | 2 +-
> arch/s390/kvm/gaccess.c | 14 ++++----
> arch/x86/include/asm/spinlock.h | 8 ++---
> arch/x86/mm/gup.c | 2 +-
> include/linux/compiler.h | 74 ++++++++++++++++++++++++++++++++++++++-
> mm/gup.c | 2 +-
> mm/memory.c | 2 +-
> mm/rmap.c | 3 +-
> 10 files changed, 95 insertions(+), 20 deletions(-)
>
FWIW, the code is on
git://git.kernel.org/pub/scm/linux/kernel/git/borntraeger/linux.git linux-next
and
git://git.kernel.org/pub/scm/linux/kernel/git/borntraeger/linux.git ACCESS_ONCE
I rebased the queue against rc3 + the initial patch that triggered the whole discussion.
Christian
next prev parent reply other threads:[~2014-12-04 15:24 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-12-03 22:30 [PATCHv4 0/9] ACCESS_ONCE and non-scalar accesses Christian Borntraeger
2014-12-03 22:30 ` [PATCH 1/9] kernel: Provide READ_ONCE and ASSIGN_ONCE Christian Borntraeger
2014-12-04 0:07 ` Paul E. McKenney
2014-12-04 9:24 ` Christian Borntraeger
2014-12-04 14:41 ` Paul E. McKenney
2014-12-03 22:30 ` [PATCH 2/9] mm: replace ACCESS_ONCE with READ_ONCE or barriers Christian Borntraeger
2014-12-04 0:09 ` Paul E. McKenney
2014-12-03 22:30 ` [PATCH 3/9] x86/spinlock: Replace ACCESS_ONCE with READ_ONCE Christian Borntraeger
2014-12-04 0:10 ` Paul E. McKenney
2014-12-03 22:30 ` [PATCH 4/9] x86/gup: " Christian Borntraeger
2014-12-04 0:10 ` Paul E. McKenney
2014-12-03 22:30 ` [PATCH 5/9] mips/gup: " Christian Borntraeger
2014-12-04 0:11 ` Paul E. McKenney
2014-12-03 22:30 ` [PATCH 6/9] arm64/spinlock: Replace ACCESS_ONCE READ_ONCE Christian Borntraeger
2014-12-04 0:11 ` Paul E. McKenney
2014-12-03 22:30 ` [PATCH 7/9] arm/spinlock: Replace ACCESS_ONCE with READ_ONCE Christian Borntraeger
2014-12-04 0:12 ` Paul E. McKenney
2014-12-03 22:30 ` [PATCH 8/9] s390/kvm: REPLACE " Christian Borntraeger
2014-12-04 0:12 ` Paul E. McKenney
2014-12-03 22:30 ` [PATCH 9/9] kernel: tighten rules for ACCESS ONCE Christian Borntraeger
2014-12-04 0:16 ` Paul E. McKenney
2014-12-04 9:28 ` Christian Borntraeger
2014-12-04 14:41 ` Paul E. McKenney
2014-12-04 15:24 ` Christian Borntraeger [this message]
2014-12-04 23:40 ` [PATCHv4 0/9] ACCESS_ONCE and non-scalar accesses Linus Torvalds
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=54807C92.1010405@de.ibm.com \
--to=borntraeger@de.ibm.com \
--cc=linux-arch@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=paulmck@linux.vnet.ibm.com \
--cc=torvalds@linux-foundation.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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.