linux.git/arch/powerpc/kernel/smp.c, branch v3.15

powerpc: Implement tick broadcast IPI as a fixed IPI message

2014-03-05T04:55:04+00:00

For scalability and performance reasons, we want the tick broadcast IPIs
to be handled as efficiently as possible. Fixed IPI messages
are one of the most efficient mechanisms available - they are faster than
the smp_call_function mechanism because the IPI handlers are fixed and hence
they don't involve costly operations such as adding IPI handlers to the target
CPU's function queue, acquiring locks for synchronization etc.

Luckily we have an unused IPI message slot, so use that to implement
tick broadcast IPIs efficiently.

Signed-off-by: Srivatsa S. Bhat 
[Functions renamed to tick_broadcast* and Changelog modified by
 Preeti U. Murthy]
Signed-off-by: Preeti U. Murthy 
Acked-by: Geoff Levand  [For the PS3 part]
Signed-off-by: Benjamin Herrenschmidt

powerpc: Free up the slot of PPC_MSG_CALL_FUNC_SINGLE IPI message

2014-03-05T04:53:24+00:00

The IPI handlers for both PPC_MSG_CALL_FUNC and PPC_MSG_CALL_FUNC_SINGLE map
to a common implementation - generic_smp_call_function_single_interrupt(). So,
we can consolidate them and save one of the IPI message slots, (which are
precious on powerpc, since only 4 of those slots are available).

So, implement the functionality of PPC_MSG_CALL_FUNC_SINGLE using
PPC_MSG_CALL_FUNC itself and release its IPI message slot, so that it can be
used for something else in the future, if desired.

Signed-off-by: Srivatsa S. Bhat 
Signed-off-by: Preeti U. Murthy 
Acked-by: Geoff Levand  [For the PS3 part]
Signed-off-by: Benjamin Herrenschmidt

Merge branch 'merge' into next

2013-12-30T04:19:31+00:00

Merge a pile of fixes that went into the "merge" branch (3.13-rc's) such
as Anton Little Endian fixes.

Signed-off-by: Benjamin Herrenschmidt

powerpc: Fix topology core_id endian issue on LE builds

2013-12-13T04:48:34+00:00

cpu_to_core_id() is missing a byteswap:

cat /sys/devices/system/cpu/cpu63/topology/core_id
201326592

Signed-off-by: Anton Blanchard 
Signed-off-by: Benjamin Herrenschmidt

powerpc: kernel: remove useless code which related with 'max_cpus'

2013-12-02T03:06:58+00:00

Since not need 'max_cpus' after the related commit, the related code
are useless too, need be removed.

The related commit:

  c1aa687 powerpc: Clean up obsolete code relating to decrementer and timebase

The related warning:

  arch/powerpc/kernel/smp.c:323:43: warning: parameter ‘max_cpus’ set but not used [-Wunused-but-set-parameter]

Signed-off-by: Chen Gang 
Reviewed-by: Srivatsa S. Bhat 
Signed-off-by: Benjamin Herrenschmidt

powerpc: Make cpu_to_chip_id() available when SMP=n

2013-11-20T23:33:44+00:00

Up until now we have only used cpu_to_chip_id() in the topology code,
which is only used on SMP builds. However my recent commit a4da0d5
"Implement arch_get_random_long/int() for powernv" added a usage when
SMP=n, breaking the build.

Move cpu_to_chip_id() into prom.c so it is available for SMP=n builds.

We would move the extern to prom.h, but that breaks the include in
topology.h. Instead we leave it in smp.h, but move it out of the
CONFIG_SMP #ifdef. We also need to include asm/smp.h in rng.c, because
the linux version skips asm/smp.h on UP. What a mess.

Signed-off-by: Michael Ellerman 
Signed-off-by: Benjamin Herrenschmidt

hotplug, powerpc, x86: Remove cpu_hotplug_driver_lock()

2013-09-30T17:55:51+00:00

cpu_hotplug_driver_lock() serializes CPU online/offline operations
when ARCH_CPU_PROBE_RELEASE is set.  This lock interface is no longer
necessary with the following reason:

 - lock_device_hotplug() now protects CPU online/offline operations,
   including the probe & release interfaces enabled by
   ARCH_CPU_PROBE_RELEASE.  The use of cpu_hotplug_driver_lock() is
   redundant.
 - cpu_hotplug_driver_lock() is only valid when ARCH_CPU_PROBE_RELEASE
   is defined, which is misleading and is only enabled on powerpc.

This patch removes the cpu_hotplug_driver_lock() interface.  As
a result, ARCH_CPU_PROBE_RELEASE only enables / disables the cpu
probe & release interface as intended.  There is no functional change
in this patch.

Signed-off-by: Toshi Kani 
Reviewed-by: Nathan Fontenot 
Signed-off-by: Rafael J. Wysocki

powerpc: Export cpu_to_chip_id() to fix build error

2013-09-11T01:39:37+00:00

powerpc allmodconfig build fails with:

ERROR: ".cpu_to_chip_id" [drivers/block/mtip32xx/mtip32xx.ko] undefined!

The problem was introduced with commit 15863ff3b (powerpc: Make chip-id
information available to userspace).

Export the missing symbol.

Cc: Vasant Hegde 
Cc: Shivaprasad G Bhat 
Signed-off-by: Guenter Roeck 
Signed-off-by: Benjamin Herrenschmidt

powerpc: Little endian SMP IPI demux

2013-08-14T05:33:37+00:00

Add little endian support for demuxing SMP IPIs

Signed-off-by: Anton Blanchard 
Signed-off-by: Benjamin Herrenschmidt

powerpc: Make chip-id information available to userspace

2013-08-14T05:33:17+00:00

So far "/sys/devices/system/cpu/cpuX/topology/physical_package_id"
was always default (-1) on ppc64 architecture.

Now, some systems have an ibm,chip-id property in the cpu nodes in
the device tree. On these systems, we now use this information to
display physical_package_id.

Signed-off-by: Vasant Hegde 
Signed-off-by: Shivaprasad G Bhat 
Signed-off-by: Benjamin Herrenschmidt