This patch enables cpuidle for pSeries and pSeries_idle is
directly called from the idle loop. As a result of pSeries_idle, cpuidle
driver registered with cpuidle subsystem comes into action. On
failure of loading of the driver or cpuidle framework default idle
is executed as part of the function. This patch
also removes the routines pseries_shared_idle_sleep and
pseries_dedicated_idle_sleep as they are now implemented as part of
pseries_idle cpuidle driver.
Signed-off-by: NDeepthi Dharwar <deepthi@linux.vnet.ibm.com>
Signed-off-by: NTrinabh Gupta <g.trinabh@gmail.com>
Signed-off-by: NArun R Bharadwaj <arun.r.bharadwaj@gmail.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

This patch implements a back-end cpuidle driver for pSeries
based on pseries_dedicated_idle_loop and pseries_shared_idle_loop
routines.  The driver is built only if CONFIG_CPU_IDLE is set. This
cpuidle driver uses global registration of idle states and
not per-cpu.
Signed-off-by: NDeepthi Dharwar <deepthi@linux.vnet.ibm.com>
Signed-off-by: NTrinabh Gupta <g.trinabh@gmail.com>
Signed-off-by: NArun R Bharadwaj <arun.r.bharadwaj@gmail.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

It turns out that there are only 2 in-tree platforms which use MPICs
which are not "primary":  IBM Cell and PowerMac.  To reduce the
complexity of the typical board setup code, invert the MPIC_PRIMARY bit
into MPIC_SECONDARY.
Signed-off-by: NKyle Moffett <Kyle.D.Moffett@boeing.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

This is used for newer IO Hubs such as p7IOC.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Some pseries IOMMUs cache TCEs but don't snoop when the TCEs are changed
in memory, hence we need manually invalidate in software.

This adds code to do the invalidate.  It keys off a device tree property
to say where the to do the MMIO for the invalidate and some information
on what the format of the invalidate including some magic routing info.

it_busno get overloaded with this magic routing info and it_index with
the MMIO address for the invalidate command.

This then gets hooked into the building and freeing of TCEs.

This is only useful on bare metal pseries.  pHyp takes care of this when
virtualised.

Based on patch from Milton with cleanups from Mikey.
Signed-off-by: NMilton Miller <miltonm@bga.com>
Signed-off-by: NMichael Neuling <mikey@neuling.org>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

None of the files touched here are modules, and they are not
exporting any symbols either -- so there is no need to be including
the module.h.  Builds of all the files remains successful.

Even kernel/module.c does not need to include it, since it includes
linux/moduleloader.h instead.
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>

All these files were including module.h just for the basic
EXPORT_SYMBOL infrastructure.  We can shift them off to the
export.h header which is a way smaller footprint and thus
realize some compile time gains.
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>

This file is only exporting symbols and so should use export.h
and not module.h header.  But in doing the conversion, we will
uncover that it was implicitly using errno.h via module.h:

  CC      arch/powerpc/platforms/pseries/hvconsole.o
arch/powerpc/platforms/pseries/hvconsole.c: In function 'hvc_put_chars':
arch/powerpc/platforms/pseries/hvconsole.c:77: error: 'EIO' undeclared (first use in this function)
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>

Removing the implicit presence of module.h from almost everywhere
will reveal this implicit usage of paca.h and string.h headers as
follows:

arch/powerpc/platforms/pseries/plpar_wrappers.h:22: error: implicit declaration of function 'get_lppaca'
arch/powerpc/platforms/pseries/plpar_wrappers.h:208: error: implicit declaration of function 'memcpy'
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>

They are getting it through device.h --> module.h path, but we want
to clean that up.  This is a sample of what will happen if we don't:

  pseries/iommu.c: In function 'tce_build_pSeriesLP':
  pseries/iommu.c:136: error: implicit declaration of function 'show_stack'

  pseries/eeh.c: In function 'eeh_token_to_phys':
  pseries/eeh.c:359: error: 'init_mm' undeclared (first use in this function)

  pseries/eeh_event.c: In function 'eeh_event_handler':
  pseries/eeh_event.c:63: error: implicit declaration of function 'daemonize'
  pseries/eeh_event.c:64: error: implicit declaration of function 'set_current_state'
  pseries/eeh_event.c:64: error: 'TASK_INTERRUPTIBLE' undeclared (first use in this function)
  pseries/eeh_event.c:64: error: (Each undeclared identifier is reported only once
  pseries/eeh_event.c:64: error: for each function it appears in.)
  pseries/eeh_event.c: In function 'eeh_thread_launcher':
  pseries/eeh_event.c:109: error: 'CLONE_KERNEL' undeclared (first use in this function)

  hotplug-cpu.c: In function 'pseries_mach_cpu_die':
  hotplug-cpu.c:115: error: implicit declaration of function 'idle_task_exit'

  kernel/swsusp_64.c: In function 'do_after_copyback':
  kernel/swsusp_64.c:17: error: implicit declaration of function 'touch_softlockup_watchdog'

  cell/spufs/context.c: In function 'alloc_spu_context':
  cell/spufs/context.c:60: error: implicit declaration of function 'get_task_mm'
  cell/spufs/context.c:60: warning: assignment makes pointer from integer without a cast
  cell/spufs/context.c: In function 'spu_forget':
  cell/spufs/context.c:127: error: implicit declaration of function 'mmput'

  pasemi/dma_lib.c: In function 'pasemi_dma_stop_chan':
  pasemi/dma_lib.c:332: error: implicit declaration of function 'cond_resched'

  sysdev/fsl_lbc.c: In function 'fsl_lbc_ctrl_irq':
  sysdev/fsl_lbc.c:247: error: 'TASK_NORMAL' undeclared (first use in this function)

Add in sched.h so these get the definitions they are looking for.
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>

They get it via module.h (via device.h) but we want to clean that up.
When we do, we'll get things like:

ibmebus.c:314: error: 'S_IWUSR' undeclared here (not in a function)
vio.c:972: error: 'S_IWUSR' undeclared here (not in a function)

so add in the stat header it is using explicitly in advance.
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>

Fix failures in powerpc associated with the previously allowed
implicit module.h presence that now lead to things like this:

arch/powerpc/mm/mmu_context_hash32.c:76:1: error: type defaults to 'int' in declaration of 'EXPORT_SYMBOL_GPL'
arch/powerpc/mm/tlb_hash32.c:48:1: error: type defaults to 'int' in declaration of 'EXPORT_SYMBOL'
arch/powerpc/kernel/pci_32.c:51:1: error: type defaults to 'int' in declaration of 'EXPORT_SYMBOL_GPL'
arch/powerpc/kernel/iomap.c:36:1: error: type defaults to 'int' in declaration of 'EXPORT_SYMBOL'
arch/powerpc/platforms/44x/canyonlands.c:126:1: error: type defaults to 'int' in declaration of 'EXPORT_SYMBOL'
arch/powerpc/kvm/44x.c:168:59: error: 'THIS_MODULE' undeclared (first use in this function)

[with several contibutions from Stephen Rothwell <sfr@canb.auug.org.au>]
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>

With module.h being implicitly everywhere via device.h, the absence
of explicitly including something for EXPORT_SYMBOL went unnoticed.
Since we are heading to fix things up and clean module.h from the
device.h file, we need to explicitly include these files now.
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>

Since commit 188917e1, /proc/ppc64 is a
symlink to /proc/powerpc/. That means that creating /proc/ppc64/eeh will
end up with a unaccessible file, that is not listed under /proc/powerpc/
and, then, not listed under /proc/ppc64/.

Creating /proc/powerpc/eeh fixes that problem and maintain the
compatibility intended with the ppc64 symlink.
Signed-off-by: NThadeu Lima de Souza Cascardo <cascardo@linux.vnet.ibm.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: <stable@kernel.org>	[3.x]

During hotplug CPU add we get the following error:

Unexpected Error (0) returned from configure-connector

ibm,configure-connector returns 0 for configuration complete, so
catch this and avoid the error.
Signed-off-by: NAnton Blanchard <anton@samba.org>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: <stable@kernel.org>

At this point, window has not been stored anywhere, so it has to be freed
before leaving the function.

A simplified version of the semantic match that finds this problem is as
follows: (http://coccinelle.lip6.fr/)

// <smpl>
@exists@
local idexpression x;
statement S,S1;
expression E;
identifier fl;
expression *ptr != NULL;
@@

x = \(kmalloc\|kzalloc\|kcalloc\)(...);
...
if (x == NULL) S
<... when != x
     when != if (...) { <+...kfree(x)...+> }
     when any
     when != true x == NULL
x->fl
...>
(
if (x == NULL) S1
|
if (...) { ... when != x
               when forall
(
 return \(0\|<+...x...+>\|ptr\);
|
* return ...;
)
}
)
// </smpl>
Signed-off-by: NJulia Lawall <julia@diku.dk>
Acked-by: NNishanth Aravamudan <nacc@us.ibm.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Capture more than twice as much text from the printk buffer, and
compress it to fit it in the lnx,oops-log NVRAM partition.  You
can view the compressed text using the new (as of July 20) --unzip
option of the nvram command in the powerpc-utils package.

[BenH: Added select of ZLIB_DEFLATE]
Signed-off-by: NJim Keniston <jkenisto@us.ibm.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Now that the generic code has dma_map_ops set, instead of having a
messy ifdef & if block in the base dma_get_required_mask hook push
the computation into the dma ops.

If the ops fails to set the get_required_mask hook default to the
width of dma_addr_t.

This also corrects ibmbus ibmebus_dma_supported to require a 64
bit mask.  I doubt anything is checking or setting the dma mask on
that bus.
Signed-off-by: NMilton Miller <miltonm@bga.com>
Signed-off-by: NNishanth Aravamudan <nacc@us.ibm.com>
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-kernel@vger.kernel.org
Cc: benh@kernel.crashing.org
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

The hook dma_get_required_mask is supposed to return the mask required
by the platform to operate efficently.  The generic version of
dma_get_required_mask in driver/base/platform.c returns a mask based
only on max_pfn.  However, this is likely too big for iommu systems
and could be too small for platforms that require a dma offset or have
a secondary window at a high offset.

Override the default, provide a hook in ppc_md used by pseries lpar and
cell, and provide the default answer based on memblock_end_of_DRAM(),
with hooks for get_dma_offset, and provide an implementation for iommu
that looks at the defined table size.  Coverting from the end address
to the required bit mask is based on the generic implementation.

The need for this was discovered when the qla2xxx driver switched to
64 bit dma then reverted to 32 bit when dma_get_required_mask said
32 bits was sufficient.
Signed-off-by: NMilton Miller <miltonm@bga.com>
Signed-off-by: NNishanth Aravamudan <nacc@us.ibm.com>
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-kernel@vger.kernel.org
Cc: benh@kernel.crashing.org
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

The VPA, SLB shadow and DTL degistration functions do not need an
address, so simplify things and remove it.

Also cleanup pseries_kexec_cpu_down a bit by storing the cpu IDs
in local variables.
Signed-off-by: NAnton Blanchard <anton@samba.org>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Make the VPA, SLB shadow and DTL registration and deregistration
functions print consistent messages on error. I needed the firmware
error code while chasing a kexec bug but we weren't printing it.
Signed-off-by: NAnton Blanchard <anton@samba.org>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Recent versions of firmware will fail to unmap the virtual processor
area if we have a dispatch trace log registered. This causes kexec
to fail.

If a trace log is registered this patch unregisters it before the
SLB shadow and virtual processor areas, fixing the problem.

The address argument is ignored by firmware on unregister so we
may as well remove it.
Signed-off-by: NAnton Blanchard <anton@samba.org>
Cc: <stable@kernel.org>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

The ibm,io-events code is a bit verbose with its error messages.
Reverse the reporting so we only print when we successfully enable
I/O event interrupts.
Signed-off-by: NAnton Blanchard <anton@samba.org>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

On a box with 8TB of RAM the MMU hashtable is 64GB in size. That
means we have 4G PTEs. pSeries_lpar_hptab_clear was using a signed
int to store the index which will overflow at 2G.
Signed-off-by: NAnton Blanchard <anton@samba.org>
Cc: <stable@kernel.org>
Acked-by: NMichael Neuling <mikey@neuling.org>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

This allows us to move duplicated code in <asm/atomic.h>
(atomic_inc_not_zero() for now) to <linux/atomic.h>
Signed-off-by: NArun Sharma <asharma@fb.com>
Reviewed-by: NEric Dumazet <eric.dumazet@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: David Miller <davem@davemloft.net>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: NMike Frysinger <vapier@gentoo.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Return -EAGAIN when we get H_BUSY back from the hypervisor. This
makes the hvc console driver retry, avoiding dropped printks.
Signed-off-by: NAnton Blanchard <anton@samba.org>
Cc: <stable@kernel.org>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Just compiling pseries in the kernel causes it to override
memory_block_size_bytes() regardless of what is the runtime
platform.

This cleans up the implementation of that function, fixing
a bug or two while at it, so that it's harmless (and potentially
useful) for other platforms. Without this, bugs in that code
would trigger a WARN_ON() in drivers/base/memory.c when
booting some different platforms.

If/when we have another platform supporting memory hotplug we
might want to either move that out to a generic place or
make it a ppc_md. callback.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

On pseries machines, consoles are provided by the hypervisor using
a low level get_chars/put_chars type interface. However, this is
really just a transport to the service processor which implements
them either as "raw" console (networked consoles, HMC, ...) or as
"hvsi" serial ports.

The later is a simple packet protocol on top of the raw character
interface that is supposed to convey additional "serial port" style
semantics. In practice however, all it does is provide a way to
read the CD line and set/clear our DTR line, that's it.

We currently implement the "raw" protocol as an hvc console backend
(/dev/hvcN) and the "hvsi" protocol using a separate tty driver
(/dev/hvsi0).

However this is quite impractical. The arbitrary difference between
the two type of devices has been a major source of user (and distro)
confusion. Additionally, there's an additional mini -hvsi implementation
in the pseries platform code for our low level debug console and early
boot kernel messages, which means code duplication, though that low
level variant is impractical as it's incapable of doing the initial
protocol negociation to establish the link to the FSP.

This essentially replaces the dedicated hvsi driver and the platform
udbg code completely by extending the existing hvc_vio backend used
in "raw" mode so that:

 - It now supports HVSI as well
 - We add support for hvc backend providing tiocm{get,set}
 - It also provides a udbg interface for early debug and boot console

This is overall less code, though this will only be obvious once we
remove the old "hvsi" driver, which is still available for now. When
the old driver is enabled, the new code still kicks in for the low
level udbg console, replacing the old mini implementation in the platform
code, it just doesn't provide the higher level "hvc" interface.

In addition to producing generally simler code, this has several benefits
over our current situation:

 - The user/distro only has to deal with /dev/hvcN for the hypervisor
console, avoiding all sort of confusion that has plagued us in the past

 - The tty, kernel and low level debug console all use the same code
base which supports the full protocol establishment process, thus the
console is now available much earlier than it used to be with the
old HVSI driver. The kernel console works much earlier and udbg is
available much earlier too. Hackers can enable a hard coded very-early
debug console as well that works with HVSI (previously that was only
supported for the "raw" mode).

I've tried to keep the same semantics as hvsi relative to how I react
to things like CD changes, with some subtle differences though:

 - I clear DTR on close if HUPCL is set

 - Current hvsi triggers a hangup if it detects a up->down transition
   on CD (you can still open a console with CD down). My new implementation
   triggers a hangup if the link to the FSP is severed, and severs it upon
   detecting a up->down transition on CD.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

When CONFIG_PPC_EARLY_DEBUG is set, call register_early_udbg_console()
early from generic code.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Reconfiguration notifier call for device node may fail by several reasons,
but it always assumes kmalloc failures.

This enables reconfiguration notifier call chain to get the actual error
code rather than -ENOMEM by converting all reconfiguration notifier calls
to return encapsulate error code with notifier_from_errno().
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: linuxppc-dev@lists.ozlabs.org
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

This introduces pSeries_reconfig_notify() as a just wrapper of
blocking_notifier_call_chain() for pSeries_reconfig_chain.

This is a preparation to improvement of error code on reconfiguration
notifier failure.
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: linuxppc-dev@lists.ozlabs.org
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Many stupid corrections of duplicated includes based on the output of
scripts/checkincludes.pl.
Signed-off-by: NVitaliy Ivanov <vitalivanov@gmail.com>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

On many platforms (including pSeries), smp_ops->message_pass is always
smp_muxed_ipi_message_pass.  This changes arch/powerpc/kernel/smp.c so
that if smp_ops->message_pass is NULL, it calls smp_muxed_ipi_message_pass
directly.

This means that a platform doesn't need to set both .message_pass and
.cause_ipi, only one of them.  It is a slight performance improvement
in that it gets rid of an indirect function call at the expense of a
predictable conditional branch.
Signed-off-by: NPaul Mackerras <paulus@samba.org>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Lenghty lists of the kind "depends on ARCH1 || ARCH2 ... || ARCH123" are
usually either wrong or too coarse grained.  Or plain an ugly sin.

[ tglx: Fixed up amigaone ]
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Acked-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: linux-alpha@vger.kernel.org
Cc: linux-mips@linux-mips.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: Gerhard Pircher <gerhard_pircher@gmx.net>
Link: http://lkml.kernel.org/r/20110601180610.984881988@duck.linux-mips.netSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

When using a property refering to the availibily of dynamic dma windows
call it ddw_avail not ddr_avail.

dupe_ddw_if_already_created does not dupilcate anything, it only finds
and reuses the windows we already created, so rename it to
find_existing_ddw.  Also, it does not need the pci device node, so
remove that argument.
Signed-off-by: NMilton Miller <miltonm@bga.com>
Signed-off-by: NNishanth Aravamudan <nacc@us.ibm.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Move the discovery of windows previously setup from when the pci driver
calls set_dma_mask to an arch_initcall.

When kexecing into a kernel with dynamic dma windows allocated, we need
to find the windows early so that memory hot remove will be able to
delete the tces mapping the to be removed memory and memory hotplug add
will map the new memory into the window.  We should not wait for the
driver to be loaded and the device to be probed.  The iommu init hooks
are before kmalloc is setup, so defer to arch_initcall.
Signed-off-by: NMilton Miller <miltonm@bga.com>
Signed-off-by: NNishanth Aravamudan <nacc@us.ibm.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

If we destroy the window, we need to remove the property recording that
we setup the window.  Otherwise the next kernel we kexec will be
confused.

Also we should remove the property if even if we don't find the
ibm,ddw-applicable window or if one of the property sizes is unexpected;
presumably these came from a prior kernel via kexec, and we will not be
maintaining the window with respect to memory hotplug.
Signed-off-by: NMilton Miller <miltonm@bga.com>
Signed-off-by: NNishanth Aravamudan <nacc@us.ibm.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Do not check dma supported until we have chosen the right dma ops.
Check that the device is pci before treating it as such.

Check the mask is supported by the selected dma ops before
committing it.

We only need to set iommu ops if it is not the current ops; this
avoids searching the tree for the iommu table unnecessarily.
Signed-off-by: NMilton Miller <miltonm@bga.com>
Signed-off-by: NNishanth Aravamudan <nacc@us.ibm.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Otherwise we get silent truncations.
Signed-off-by: NNishanth Aravamudan <nacc@us.ibm.com>
Cc: Anton Blanchard <anton@samba.org>
Cc: Milton Miller <miltonm@bga.com>
Cc: linuxppc-dev@ozlabs.org
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Consolidate the mux and demux of ipi messages into smp.c and call
a new smp_ops callback to actually trigger the ipi.

The powerpc architecture code is optimised for having 4 distinct
ipi triggers, which are mapped to 4 distinct messages (ipi many, ipi
single, scheduler ipi, and enter debugger).  However, several interrupt
controllers only provide a single software triggered interrupt that
can be delivered to each cpu.  To resolve this limitation, each smp_ops
implementation created a per-cpu variable that is manipulated with atomic
bitops.  Since these lines will be contended they are optimialy marked as
shared_aligned and take a full cache line for each cpu.  Distro kernels
may have 2 or 3 of these in their config, each taking per-cpu space
even though at most one will be in use.

This consolidation removes smp_message_recv and replaces the single call
actions cases with direct calls from the common message recognition loop.
The complicated debugger ipi case with its muxed crash handling code is
moved to debug_ipi_action which is now called from the demux code (instead
of the multi-message action calling smp_message_recv).

I put a call to reschedule_action to increase the likelyhood of correctly
merging the anticipated scheduler_ipi() hook coming from the scheduler
tree; that single required call can be inlined later.

The actual message decode is a copy of the old pseries xics code with its
memory barriers and cache line spacing, augmented with a per-cpu unsigned
long based on the book-e doorbell code.  The optional data is set via a
callback from the implementation and is passed to the new cause-ipi hook
along with the logical cpu number.  While currently only the doorbell
implemntation uses this data it should be almost zero cost to retrieve and
pass it -- it adds a single register load for the argument from the same
cache line to which we just completed a store and the register is dead
on return from the call.  I extended the data element from unsigned int
to unsigned long in case some other code wanted to associate a pointer.

The doorbell check_self is replaced by a call to smp_muxed_ipi_resend,
conditioned on the CPU_DBELL feature.  The ifdef guard could be relaxed
to CONFIG_SMP but I left it with BOOKE for now.

Also, the doorbell interrupt vector for book-e was not calling irq_enter
and irq_exit, which throws off cpu accounting and causes code to not
realize it is running in interrupt context.  Add the missing calls.
Signed-off-by: NMilton Miller <miltonm@bga.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>