From: catalin.marinas@arm•com (Catalin Marinas)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH 07/16] ARM: bL_platsmp.c: close the kernel entry gate before hot-unplugging a CPU
Date: Mon, 14 Jan 2013 17:11:49 +0000 [thread overview]
Message-ID: <20130114171149.GE23616@arm.com> (raw)
In-Reply-To: <20130114170028.GD31341@mudshark.cambridge.arm.com>
On Mon, Jan 14, 2013 at 05:00:28PM +0000, Will Deacon wrote:
> On Mon, Jan 14, 2013 at 04:53:41PM +0000, Nicolas Pitre wrote:
> > On Mon, 14 Jan 2013, Will Deacon wrote:
> >
> > > On Thu, Jan 10, 2013 at 12:20:42AM +0000, Nicolas Pitre wrote:
> > > > If for whatever reason a CPU is unexpectedly awaken, it shouldn't
> > > > re-enter the kernel by using whatever entry vector that might have
> > > > been set by a previous operation.
> > > >
> > > > Signed-off-by: Nicolas Pitre <nico@linaro•org>
> > > > ---
> > > > arch/arm/common/bL_platsmp.c | 5 +++++
> > > > 1 file changed, 5 insertions(+)
> > > >
> > > > diff --git a/arch/arm/common/bL_platsmp.c b/arch/arm/common/bL_platsmp.c
> > > > index 0acb9f4685..0ae44123bf 100644
> > > > --- a/arch/arm/common/bL_platsmp.c
> > > > +++ b/arch/arm/common/bL_platsmp.c
> > > > @@ -63,6 +63,11 @@ static int bL_cpu_disable(unsigned int cpu)
> > > >
> > > > static void __ref bL_cpu_die(unsigned int cpu)
> > > > {
> > > > + unsigned int mpidr, pcpu, pcluster;
> > > > + asm ("mrc p15, 0, %0, c0, c0, 5" : "=r" (mpidr));
> > > > + pcpu = mpidr & 0xff;
> > > > + pcluster = (mpidr >> 8) & 0xff;
> > >
> > > Usual comment about helper functions :)
> > >
> > > > + bL_set_entry_vector(pcpu, pcluster, NULL);
> > >
> > > Similar to the power_on story, you need a barrier here (unless you change
> > > your platform_ops API to require barriers).
> >
> > The bL_set_entry_vector() includes a cache flush which itself has a DSB.
> > Hence my previous interrogation.
>
> For L1, sure, we always have the dsb for v7. However, for the outer-cache we
> only have a dsb by virtue of a spin_unlock in l2x0.c... it seems a bit risky
> to rely on that for ordering your entry_vector write with the power_on.
I was discussing this with Dave earlier, I think we need to fix the
outer-cache functions even for the UP case to include a barrier (for
PL310 actually we may need to read a register as the cache_wait is a
no-op). We assume that cache functions (both inner and outer) fully
complete the operation before returning and there is no additional need
for barriers.
--
Catalin
next prev parent reply other threads:[~2013-01-14 17:11 UTC|newest]
Thread overview: 132+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-10 0:20 [PATCH 00/16] big.LITTLE low-level CPU and cluster power management Nicolas Pitre
2013-01-10 0:20 ` [PATCH 01/16] ARM: b.L: secondary kernel entry code Nicolas Pitre
2013-01-10 7:12 ` Stephen Boyd
2013-01-10 15:30 ` Nicolas Pitre
2013-01-10 15:34 ` Catalin Marinas
2013-01-10 16:47 ` Nicolas Pitre
2013-01-11 11:45 ` Catalin Marinas
2013-01-11 12:05 ` Lorenzo Pieralisi
2013-01-11 12:19 ` Dave Martin
2013-01-10 23:05 ` Will Deacon
2013-01-11 1:26 ` Nicolas Pitre
2013-01-11 10:55 ` Will Deacon
2013-01-11 11:35 ` Dave Martin
2013-01-11 17:16 ` Santosh Shilimkar
2013-01-11 18:10 ` Nicolas Pitre
2013-01-11 18:30 ` Santosh Shilimkar
2013-03-07 7:37 ` Pavel Machek
2013-03-07 8:57 ` Nicolas Pitre
2013-01-10 0:20 ` [PATCH 02/16] ARM: b.L: introduce the CPU/cluster power API Nicolas Pitre
2013-01-10 23:08 ` Will Deacon
2013-01-11 2:30 ` Nicolas Pitre
2013-01-11 10:58 ` Will Deacon
2013-01-11 11:29 ` Dave Martin
2013-01-11 17:26 ` Santosh Shilimkar
2013-01-11 18:33 ` Nicolas Pitre
2013-01-11 18:41 ` Santosh Shilimkar
2013-01-11 19:54 ` Nicolas Pitre
2013-01-10 0:20 ` [PATCH 03/16] ARM: b.L: introduce helpers for platform coherency exit/setup Nicolas Pitre
2013-01-10 12:01 ` Dave Martin
2013-01-10 19:04 ` Nicolas Pitre
2013-01-11 11:30 ` Dave Martin
2013-01-10 16:53 ` Catalin Marinas
2013-01-10 17:59 ` Nicolas Pitre
2013-01-10 21:50 ` Catalin Marinas
2013-01-10 22:31 ` Nicolas Pitre
2013-01-11 10:36 ` Dave Martin
2013-01-10 22:32 ` Nicolas Pitre
2013-01-10 23:13 ` Will Deacon
2013-01-11 1:50 ` Nicolas Pitre
2013-01-11 11:09 ` Dave Martin
2013-01-11 17:46 ` Santosh Shilimkar
2013-01-11 18:07 ` Dave Martin
2013-01-11 18:34 ` Santosh Shilimkar
2013-01-14 17:08 ` Dave Martin
2013-01-14 17:15 ` Catalin Marinas
2013-01-14 18:10 ` Dave Martin
2013-01-14 21:34 ` Catalin Marinas
2013-01-10 0:20 ` [PATCH 04/16] ARM: b.L: Add baremetal voting mutexes Nicolas Pitre
2013-01-10 23:18 ` Will Deacon
2013-01-11 3:15 ` Nicolas Pitre
2013-01-11 11:03 ` Will Deacon
2013-01-11 16:57 ` Dave Martin
2013-01-10 0:20 ` [PATCH 05/16] ARM: bL_head: vlock-based first man election Nicolas Pitre
2013-01-10 0:20 ` [PATCH 06/16] ARM: b.L: generic SMP secondary bringup and hotplug support Nicolas Pitre
2013-01-11 18:02 ` Santosh Shilimkar
2013-01-14 18:05 ` Achin Gupta
2013-01-15 6:32 ` Santosh Shilimkar
2013-01-15 11:18 ` Achin Gupta
2013-01-15 11:26 ` Santosh Shilimkar
2013-01-15 18:53 ` Dave Martin
2013-01-14 16:35 ` Will Deacon
2013-01-14 16:51 ` Nicolas Pitre
2013-01-15 19:09 ` Dave Martin
2013-01-10 0:20 ` [PATCH 07/16] ARM: bL_platsmp.c: close the kernel entry gate before hot-unplugging a CPU Nicolas Pitre
2013-01-14 16:37 ` Will Deacon
2013-01-14 16:53 ` Nicolas Pitre
2013-01-14 17:00 ` Will Deacon
2013-01-14 17:11 ` Catalin Marinas [this message]
2013-01-14 17:15 ` Nicolas Pitre
2013-01-14 17:23 ` Will Deacon
2013-01-14 18:26 ` Russell King - ARM Linux
2013-01-14 18:49 ` Nicolas Pitre
2013-01-15 18:40 ` Dave Martin
2013-01-16 16:06 ` Catalin Marinas
2013-01-10 0:20 ` [PATCH 08/16] ARM: bL_platsmp.c: make sure the GIC interface of a dying CPU is disabled Nicolas Pitre
2013-01-11 18:07 ` Santosh Shilimkar
2013-01-11 19:07 ` Nicolas Pitre
2013-01-12 6:50 ` Santosh Shilimkar
2013-01-12 16:47 ` Nicolas Pitre
2013-01-13 4:37 ` Santosh Shilimkar
2013-01-14 17:53 ` Lorenzo Pieralisi
2013-01-14 16:39 ` Will Deacon
2013-01-14 16:54 ` Nicolas Pitre
2013-01-14 17:02 ` Will Deacon
2013-01-14 17:18 ` Nicolas Pitre
2013-01-14 17:24 ` Will Deacon
2013-01-14 17:56 ` Lorenzo Pieralisi
2013-01-10 0:20 ` [PATCH 09/16] ARM: vexpress: Select the correct SMP operations at run-time Nicolas Pitre
2013-01-10 0:20 ` [PATCH 10/16] ARM: vexpress: introduce DCSCB support Nicolas Pitre
2013-01-11 18:12 ` Santosh Shilimkar
2013-01-11 19:13 ` Nicolas Pitre
2013-01-12 6:52 ` Santosh Shilimkar
2013-01-10 0:20 ` [PATCH 11/16] ARM: vexpress/dcscb: add CPU use counts to the power up/down API implementation Nicolas Pitre
2013-01-10 0:20 ` [PATCH 12/16] ARM: vexpress/dcscb: do not hardcode number of CPUs per cluster Nicolas Pitre
2013-01-10 0:20 ` [PATCH 13/16] drivers: misc: add ARM CCI support Nicolas Pitre
2013-01-11 18:20 ` Santosh Shilimkar
2013-01-11 19:22 ` Nicolas Pitre
2013-01-12 6:53 ` Santosh Shilimkar
2013-01-15 18:34 ` Dave Martin
2013-01-10 0:20 ` [PATCH 14/16] ARM: TC2: ensure powerdown-time data is flushed from cache Nicolas Pitre
2013-01-10 18:50 ` Dave Martin
2013-01-10 19:13 ` Nicolas Pitre
2013-01-11 11:38 ` Dave Martin
2013-01-10 0:20 ` [PATCH 15/16] ARM: vexpress/dcscb: handle platform coherency exit/setup and CCI Nicolas Pitre
2013-01-10 12:05 ` Dave Martin
2013-01-11 18:27 ` Santosh Shilimkar
2013-01-11 19:28 ` Nicolas Pitre
2013-01-12 7:21 ` Santosh Shilimkar
2013-01-14 12:25 ` Lorenzo Pieralisi
2013-01-15 6:23 ` Santosh Shilimkar
2013-01-15 18:20 ` Dave Martin
2013-01-16 6:33 ` Santosh Shilimkar
2013-01-16 10:03 ` Lorenzo Pieralisi
2013-01-16 10:12 ` Santosh Shilimkar
2013-01-10 0:20 ` [PATCH 16/16] ARM: vexpress/dcscb: probe via device tree Nicolas Pitre
2013-01-10 0:46 ` [PATCH 00/16] big.LITTLE low-level CPU and cluster power management Rob Herring
2013-01-10 5:04 ` Nicolas Pitre
2013-01-10 23:01 ` Will Deacon
2013-01-14 9:56 ` Joseph Lo
2013-01-14 14:05 ` Nicolas Pitre
2013-01-15 2:44 ` Joseph Lo
2013-01-15 16:44 ` Nicolas Pitre
2013-01-16 16:02 ` Catalin Marinas
2013-01-16 21:18 ` Nicolas Pitre
2013-01-17 17:55 ` Catalin Marinas
2013-01-15 18:31 ` Dave Martin
2013-03-07 8:27 ` Pavel Machek
2013-03-07 9:12 ` Nicolas Pitre
2013-03-07 9:40 ` Pavel Machek
2013-03-07 9:56 ` Nicolas Pitre
2013-03-07 14:51 ` Pavel Machek
2013-03-07 15:42 ` Nicolas Pitre
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