kernel/arch/powerpc/include/asm/smp.h, branch linux-4.3.y

powerpc: Drop return value of smp_ops->probe()

2015-04-10T10:02:49Z

smp_ops->probe() is currently supposed to return the number of cpus in the system. The last actual usage of the value was removed in May 2007 in e147ec8f1808 "[POWERPC] Simplify smp_space_timers". We still passed the value around until June 2010 when even that was finally removed in c1aa687d499a "powerpc: Clean up obsolete code relating to decrementer and timebase". So drop that requirement, probe() now returns void, and update all implementations. Signed-off-by: Michael Ellerman

powerpc: Remove the celleb support

2015-04-07T07:15:13Z

The celleb code has seen no actual development for ~7 years. We (maintainers) have no access to test hardware, and it is highly likely the code has bit-rotted. As far as we're aware the hardware was never widely available, and is certainly no longer available, and no one on the list has shown any interest in it over the years. So remove it. If anyone has one and cares please speak up. Signed-off-by: Michael Ellerman Acked-by: Benjamin Herrenschmidt Acked-by: Jeremy Kerr

powerpc: Remove some unused functions

2015-01-28T04:00:24Z

Remove slice_set_psize() which is not used. It was added in 3a8247cc2c85 "powerpc: Only demote individual slices rather than whole process" but was never used. Remove vsx_assist_exception() which is not used. It was added in ce48b2100785 "powerpc: Add VSX context save/restore, ptrace and signal support" but was never used. Remove generic_mach_cpu_die() which is not used. Its last caller was removed in 375f561a4131 "powerpc/powernv: Always go into nap mode when CPU is offline". Remove mpc7448_hpc2_power_off() and mpc7448_hpc2_halt() which are unused. These were introduced in c5d56332fd6c "[POWERPC] Add general support for mpc7448hpc2 (Taiga) platform" but were never used. This was partially found by using a static code analysis program called cppcheck. Signed-off-by: Rickard Strandqvist [mpe: Update changelog with details on when/why they are unused] Signed-off-by: Michael Ellerman

powerpc/kvm/book3s_hv: Rework the secondary inhibit code

2014-05-28T03:35:34Z

As part of the support for split core on POWER8, we want to be able to block splitting of the core while KVM VMs are active. The logic to do that would be exactly the same as the code we currently have for inhibiting onlining of secondaries. Instead of adding an identical mechanism to block split core, rework the secondary inhibit code to be a "HV KVM is active" check. We can then use that in both the cpu hotplug code and the upcoming split core code. Signed-off-by: Michael Ellerman Signed-off-by: Michael Neuling Acked-by: Alexander Graf Acked-by: Paul Mackerras Signed-off-by: Benjamin Herrenschmidt

powerpc: Implement tick broadcast IPI as a fixed IPI message

2014-03-05T04:55:04Z

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

2014-03-05T04:53:24Z

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

powerpc: Make cpu_to_chip_id() available when SMP=n

2013-11-20T23:33:44Z

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

powerpc: Make chip-id information available to userspace

2013-08-14T05:33:17Z

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

powerpc: Add smp_generic_cpu_bootable

2013-08-14T04:56:50Z

Cell and PSeries both implemented their own versions of a cpu_bootable smp_op which do the same thing (well, the PSeries one has support for more than 2 threads). Copy the PSeries one to generic code, and rename it smp_generic_cpu_bootable. Signed-off-by: Andy Fleming Signed-off-by: Benjamin Herrenschmidt

powerpc: VPHN topology change updates all siblings

2013-08-01T03:11:47Z

When an associativity level change is found for one thread, the siblings threads need to be updated as well. This is done today for PRRN in stage_topology_update() but is missing for VPHN in update_cpu_associativity_changes_mask(). This patch will correctly update all thread siblings during a topology change. Without this patch a topology update can result in a CPU in init_sched_groups_power() getting stuck indefinitely in a loop. This loop is built in build_sched_groups(). As a result of the thread moving to a node separate from its siblings the struct sched_group will have its next pointer set to point to itself rather than the sched_group struct of the next thread. This happens because we have a domain without the SD_OVERLAP flag, which is correct, and a topology that doesn't conform with reality (threads on the same core assigned to different numa nodes). When this list is traversed by init_sched_groups_power() it will reach the thread's sched_group structure and loop indefinitely; the cpu will be stuck at this point. The bug was exposed when VPHN was enabled in commit b7abef0 (v3.9). Cc: [v3.9+] Reported-by: Jan Stancek Signed-off-by: Robert Jennings Signed-off-by: Benjamin Herrenschmidt