From: konrad.wilk@oracle•com (Konrad Rzeszutek Wilk)
To: linux-arm-kernel@lists•infradead.org
Subject: [Xen-devel] [PATCH 04/24] xen/arm: sync_bitops
Date: Wed, 1 Aug 2012 10:35:51 -0400 [thread overview]
Message-ID: <20120801143551.GI7227@phenom.dumpdata.com> (raw)
In-Reply-To: <1343381305.6812.116.camel@zakaz.uk.xensource.com>
On Fri, Jul 27, 2012 at 10:28:25AM +0100, Ian Campbell wrote:
> On Thu, 2012-07-26 at 17:37 +0100, Konrad Rzeszutek Wilk wrote:
> > On Thu, Jul 26, 2012 at 04:33:46PM +0100, Stefano Stabellini wrote:
> > > sync_bitops functions are equivalent to the SMP implementation of the
> > > original functions, independently from CONFIG_SMP being defined.
> >
> > So why can't the code be changed to use that? Is it that
> > the _set_bit, _clear_bit, etc are not available with !CONFIG_SMP?
>
> _set_bit etc are not SMP safe if !CONFIG_SMP. But under Xen you might be
> communicating with a completely external entity who might be on another
> CPU (e.g. two uniprocessor guests communicating via event channels and
> grant tables). So we need a variant of the bit ops which are SMP safe
> even on a UP kernel.
>
> The users are common code and the sync_foo vs foo distinction matters on
> some platforms (e.g. x86 where a UP kernel would omit the LOCK prefix
> for the normal ones).
OK, that makes sense. Stefano can you include that comment in the git
commit description and in the sync_bitops.h file please?
>
> >
> > >
> > > Signed-off-by: Stefano Stabellini <stefano.stabellini@eu•citrix.com>
> > > ---
> > > arch/arm/include/asm/sync_bitops.h | 17 +++++++++++++++++
> > > 1 files changed, 17 insertions(+), 0 deletions(-)
> > > create mode 100644 arch/arm/include/asm/sync_bitops.h
> > >
> > > diff --git a/arch/arm/include/asm/sync_bitops.h b/arch/arm/include/asm/sync_bitops.h
> > > new file mode 100644
> > > index 0000000..d975092903
> > > --- /dev/null
> > > +++ b/arch/arm/include/asm/sync_bitops.h
> > > @@ -0,0 +1,17 @@
> > > +#ifndef __ASM_SYNC_BITOPS_H__
> > > +#define __ASM_SYNC_BITOPS_H__
> > > +
> > > +#include <asm/bitops.h>
> > > +#include <asm/system.h>
> > > +
> > > +#define sync_set_bit(nr, p) _set_bit(nr, p)
> > > +#define sync_clear_bit(nr, p) _clear_bit(nr, p)
> > > +#define sync_change_bit(nr, p) _change_bit(nr, p)
> > > +#define sync_test_and_set_bit(nr, p) _test_and_set_bit(nr, p)
> > > +#define sync_test_and_clear_bit(nr, p) _test_and_clear_bit(nr, p)
> > > +#define sync_test_and_change_bit(nr, p) _test_and_change_bit(nr, p)
> > > +#define sync_test_bit(nr, addr) test_bit(nr, addr)
> > > +#define sync_cmpxchg cmpxchg
> > > +
> > > +
> > > +#endif
> > > --
> > > 1.7.2.5
> > >
> > >
> > > _______________________________________________
> > > Xen-devel mailing list
> > > Xen-devel at lists.xen.org
> > > http://lists.xen.org/xen-devel
>
next prev parent reply other threads:[~2012-08-01 14:35 UTC|newest]
Thread overview: 99+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-07-26 15:33 [PATCH 00/24] Introduce Xen support on ARM Stefano Stabellini
2012-07-26 15:33 ` [PATCH 01/24] arm: initial Xen support Stefano Stabellini
2012-07-26 16:30 ` [Xen-devel] " Konrad Rzeszutek Wilk
2012-07-27 11:56 ` Stefano Stabellini
2012-08-01 10:42 ` Konrad Rzeszutek Wilk
2012-08-06 10:55 ` Stefano Stabellini
2012-08-01 18:27 ` Rob Herring
2012-08-02 7:35 ` Ian Campbell
2012-08-02 14:13 ` [Xen-devel] " Konrad Rzeszutek Wilk
2012-08-06 10:46 ` Stefano Stabellini
2012-07-26 15:33 ` [PATCH 02/24] xen/arm: hypercalls Stefano Stabellini
2012-07-26 16:33 ` [Xen-devel] " Konrad Rzeszutek Wilk
2012-07-27 9:17 ` Ian Campbell
2012-07-27 13:02 ` Stefano Stabellini
2012-07-27 13:18 ` Ian Campbell
2012-07-27 13:41 ` Stefano Stabellini
2012-07-27 14:21 ` Russell King - ARM Linux
2012-07-27 14:36 ` Stefano Stabellini
2012-07-27 14:39 ` Ian Campbell
2012-07-27 14:59 ` Russell King - ARM Linux
2012-07-26 16:56 ` David Vrabel
2012-07-26 17:19 ` Stefano Stabellini
2012-07-27 9:00 ` Ian Campbell
2012-07-26 19:19 ` Christopher Covington
2012-07-27 9:19 ` Ian Campbell
2012-07-27 12:56 ` Christopher Covington
2012-07-27 13:57 ` Stefano Stabellini
2012-07-26 15:33 ` [PATCH 03/24] xen/arm: page.h definitions Stefano Stabellini
2012-07-26 16:36 ` [Xen-devel] " Konrad Rzeszutek Wilk
2012-07-27 13:47 ` Stefano Stabellini
2012-07-26 15:33 ` [PATCH 04/24] xen/arm: sync_bitops Stefano Stabellini
2012-07-26 16:37 ` [Xen-devel] " Konrad Rzeszutek Wilk
2012-07-27 9:28 ` Ian Campbell
2012-08-01 14:35 ` Konrad Rzeszutek Wilk [this message]
2012-08-01 16:07 ` Stefano Stabellini
2012-07-26 15:33 ` [PATCH 05/24] xen/arm: empty implementation of grant_table arch specific functions Stefano Stabellini
2012-08-01 14:16 ` Konrad Rzeszutek Wilk
2012-08-01 15:46 ` Stefano Stabellini
2012-07-26 15:33 ` [PATCH 06/24] xen: missing includes Stefano Stabellini
2012-07-27 6:57 ` [Xen-devel] " Jan Beulich
2012-07-27 16:47 ` Stefano Stabellini
2012-07-26 15:33 ` [PATCH 07/24] xen/arm: Xen detection and shared_info page mapping Stefano Stabellini
2012-07-27 9:36 ` Ian Campbell
2012-07-27 14:48 ` Stefano Stabellini
2012-07-27 14:51 ` Ian Campbell
2012-08-01 14:19 ` Konrad Rzeszutek Wilk
2012-08-01 15:45 ` Stefano Stabellini
2012-07-26 15:33 ` [PATCH 08/24] xen/arm: Introduce xen_pfn_t for pfn and mfn types Stefano Stabellini
2012-08-01 14:22 ` Konrad Rzeszutek Wilk
2012-08-01 15:50 ` Stefano Stabellini
2012-07-26 15:33 ` [PATCH 09/24] xen/arm: compile and run xenbus Stefano Stabellini
2012-08-01 14:28 ` Konrad Rzeszutek Wilk
2012-08-06 11:17 ` Stefano Stabellini
2012-07-26 15:33 ` [PATCH 10/24] xen: do not compile manage, balloon, pci, acpi and cpu_hotplug on ARM Stefano Stabellini
2012-07-27 7:01 ` [Xen-devel] " Jan Beulich
2012-07-27 16:51 ` Stefano Stabellini
2012-07-26 15:33 ` [PATCH 11/24] xen/arm: introduce CONFIG_XEN " Stefano Stabellini
2012-08-01 14:34 ` [Xen-devel] " Konrad Rzeszutek Wilk
2012-07-26 15:33 ` [PATCH 12/24] xen/arm: Introduce xen_guest_init Stefano Stabellini
2012-07-27 9:42 ` Ian Campbell
2012-07-27 15:54 ` Stefano Stabellini
2012-07-27 16:11 ` Ian Campbell
2012-08-01 14:38 ` Konrad Rzeszutek Wilk
2012-07-26 15:33 ` [PATCH 13/24] xen/arm: get privilege status Stefano Stabellini
2012-07-27 9:44 ` Ian Campbell
2012-07-27 14:25 ` Stefano Stabellini
2012-07-27 14:33 ` Ian Campbell
2012-08-01 14:39 ` Konrad Rzeszutek Wilk
2012-08-01 16:21 ` Stefano Stabellini
2012-07-26 15:33 ` [PATCH 14/24] xen/arm: initialize grant_table on ARM Stefano Stabellini
2012-08-01 14:40 ` Konrad Rzeszutek Wilk
2012-08-01 17:08 ` Stefano Stabellini
2012-07-26 15:33 ` [PATCH 15/24] xen/arm: receive Xen events " Stefano Stabellini
2012-08-01 14:44 ` Konrad Rzeszutek Wilk
2012-08-06 10:31 ` Stefano Stabellini
2012-07-26 15:33 ` [PATCH 16/24] xen/arm: implement alloc/free_xenballooned_pages with alloc_pages/kfree Stefano Stabellini
2012-07-26 15:33 ` [PATCH 17/24] xen: allow privcmd for HVM guests Stefano Stabellini
2012-07-27 7:04 ` [Xen-devel] " Jan Beulich
2012-07-27 14:10 ` Stefano Stabellini
2012-08-01 14:47 ` Konrad Rzeszutek Wilk
2012-07-26 15:34 ` [PATCH 18/24] xen/arm: compile blkfront and blkback Stefano Stabellini
2012-07-27 9:48 ` Ian Campbell
2012-07-27 16:25 ` Stefano Stabellini
2012-08-01 14:48 ` Konrad Rzeszutek Wilk
2012-08-01 16:19 ` Stefano Stabellini
2012-07-26 15:34 ` [PATCH 19/24] xen/arm: compile netback Stefano Stabellini
2012-07-26 15:34 ` [PATCH 20/24] xen: update xen_add_to_physmap interface Stefano Stabellini
2012-08-01 14:52 ` Konrad Rzeszutek Wilk
2012-08-01 16:18 ` Stefano Stabellini
2012-08-01 18:19 ` Mukesh Rathor
2012-07-26 15:34 ` [PATCH 21/24] arm/v2m: initialize arch_timers even if v2m_timer is not present Stefano Stabellini
2012-08-01 14:52 ` Konrad Rzeszutek Wilk
2012-08-01 16:06 ` Stefano Stabellini
2012-07-26 15:34 ` [PATCH 22/24] ARM: enable earlyprintk=xen Stefano Stabellini
2012-07-26 15:34 ` [PATCH 23/24] hvc_xen: allow dom0_write_console for HVM guests Stefano Stabellini
2012-08-01 14:54 ` Konrad Rzeszutek Wilk
2012-08-01 16:04 ` Stefano Stabellini
2012-07-26 15:34 ` [PATCH 24/24] [HACK] xen/arm: implement xen_remap_domain_mfn_range Stefano Stabellini
2012-08-01 14:56 ` Konrad Rzeszutek Wilk
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