linux/arch/mips/kernel/smp.c, branch v4.11

sched/headers: Prepare to remove the dependency from

2017-03-02T07:42:37Z

Update code that relied on sched.h including various MM types for them. This will allow us to remove the include from . Acked-by: Linus Torvalds Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar

MIPS: kexec: remove SMP_DUMP

2017-01-03T15:34:44Z

SMP_DUMP has been added as a new IPI signal when kexec support was added for Cavium Octeon CPUs ('commit 7aa1c8f47e7e ("MIPS: kdump: Add support")'. However, the new signal doesn't appear to ever have a proper handler added (octeon_message_functions[] array has an empty handler for it), and generic IPI handlers now trigger a BUG() on unhandled signal. As the method is unused remove it completely and replace its only invocation with a smp_call_function(). [ralf@linux-mips.org: Renumber SMP_ASK_C0COUNT to avoid numbering gaps.] Signed-off-by: Marcin Nowakowski Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/14630/ Signed-off-by: Ralf Baechle

MIPS: SMP: Remove cpu_callin_map

2017-01-03T15:34:38Z

The previous commit made cpu_callin_map redundant, since it is no longer used to signal secondary CPUs starting, or going offline. Remove it now. Signed-off-by: Matt Redfearn Cc: Sebastian Andrzej Siewior Cc: Qais Yousef Cc: Masahiro Yamada Cc: Huacai Chen Cc: Kevin Cernekee Cc: Thomas Gleixner Cc: Andrew Morton Cc: James Hogan Cc: Paul Burton Cc: Florian Fainelli Cc: Anna-Maria Gleixner Cc: Adam Buchbinder Cc: Yang Shi Cc: David Daney Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/14503/ Signed-off-by: Ralf Baechle

MIPS: SMP: Use a completion event to signal CPU up

2017-01-03T15:34:38Z

If a secondary CPU failed to start, for any reason, the CPU requesting the secondary to start would get stuck in the loop waiting for the secondary to be present in the cpu_callin_map. Rather than that, use a completion event to signal that the secondary CPU has started and is waiting to synchronise counters. Since the CPU presence will no longer be marked in cpu_callin_map, remove the redundant test from arch_cpu_idle_dead(). Signed-off-by: Matt Redfearn Cc: Maciej W. Rozycki Cc: Jiri Slaby Cc: Paul Gortmaker Cc: Chris Metcalf Cc: Thomas Gleixner Cc: Qais Yousef Cc: James Hogan Cc: Paul Burton Cc: Marcin Nowakowski Cc: Andrew Morton Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/14502/ Signed-off-by: Ralf Baechle

MIPS: kernel: Audit and remove any unnecessary uses of module.h

2016-10-04T23:31:20Z

Historically a lot of these existed because we did not have a distinction between what was modular code and what was providing support to modules via EXPORT_SYMBOL and friends. That changed when we forked out support for the latter into the export.h file. This means we should be able to reduce the usage of module.h in code that is obj-y Makefile or bool Kconfig. The advantage in doing so is that module.h itself sources about 15 other headers; adding significantly to what we feed cpp, and it can obscure what headers we are effectively using. Since module.h was the source for init.h (for __init) and for export.h (for EXPORT_SYMBOL) we consider each obj-y/bool instance for the presence of either and replace as needed. In the case of the n32/o32 files, we have to get rid of a couple no-op MODULE_ tags to facilitate the module.h removal. They piggy back off the fs/ elf binary support, which is also a bool Kconfig. Signed-off-by: Paul Gortmaker Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/14032/ Signed-off-by: Ralf Baechle

MIPS: smp.c: Introduce mechanism for freeing and allocating IPIs

2016-10-04T23:31:20Z

For the MIPS remote processor implementation, we need additional IPIs to talk to the remote processor. Since MIPS GIC reserves exactly the right number of IPI IRQs required by Linux for the number of VPs in the system, this is not possible without releasing some recources. This commit introduces mips_smp_ipi_allocate() which allocates IPIs to a given cpumask. It is called as normal with the cpu_possible_mask at bootup to initialise IPIs to all CPUs. mips_smp_ipi_free() may then be used to free IPIs to a subset of those CPUs so that their hardware resources can be reused. Signed-off-by: Matt Redfearn Cc: Bjorn Andersson Cc: Ohad Ben-Cohen Cc: Thomas Gleixner Cc: Lisa Parratt Cc: James Hogan Cc: Qais Yousef Cc: Paul Burton Cc: linux-mips@linux-mips.org Cc: linux-remoteproc@vger.kernel.org Cc: lisa.parratt@imgtec.com Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/14285/ Signed-off-by: Ralf Baechle

MIPS: SMP: Wrap call to mips_cpc_lock_other in mips_cm_lock_other

2016-10-04T14:13:57Z

All calls to mips_cpc_lock_other should be wrapped in mips_cm_lock_other. This only matters if the system has CM3 and is using cpu idle, since otherwise a) the CPC lock is sufficent for CM < 3 and b) any systems with CM > 3 have not been able to use cpu idle until now. Signed-off-by: Matt Redfearn Reviewed-by: Paul Burton Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Cc: Thomas Gleixner Cc: James Hogan Cc: Qais Yousef Patchwork: https://patchwork.linux-mips.org/patch/14227/ Signed-off-by: Ralf Baechle

MIPS: SMP: Fix possibility of deadlock when bringing CPUs online

2016-09-24T23:43:52Z

This patch fixes the possibility of a deadlock when bringing up secondary CPUs. The deadlock occurs because the set_cpu_online() is called before synchronise_count_slave(). This can cause a deadlock if the boot CPU, having scheduled another thread, attempts to send an IPI to the secondary CPU, which it sees has been marked online. The secondary is blocked in synchronise_count_slave() waiting for the boot CPU to enter synchronise_count_master(), but the boot cpu is blocked in smp_call_function_many() waiting for the secondary to respond to it's IPI request. Fix this by marking the CPU online in cpu_callin_map and synchronising counters before declaring the CPU online and calculating the maps for IPIs. Signed-off-by: Matt Redfearn Reported-by: Justin Chen Tested-by: Justin Chen Cc: Florian Fainelli Cc: stable@vger.kernel.org # v4.1+ Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/14302/ Signed-off-by: Ralf Baechle

MIPS: c-r4k: Exclude sibling CPUs in SMP calls

2016-07-29T08:19:29Z

When performing SMP calls to foreign cores, exclude sibling CPUs from the provided map, as we already handle the local core on the current CPU. This prevents an SMP call from for example core 0, VPE 1 to VPE 0 on the same core. In the process the cpu_foreign_map cpumask is turned into an array of cpumasks, so that each CPU has its own version of it which excludes sibling CPUs. r4k_op_needs_ipi() is also updated to reflect that cache management SMP calls are not needed when all CPUs are siblings (i.e. there are no foreign CPUs according to the new cpu_foreign_map[] semantics which exclude siblings). Signed-off-by: James Hogan Cc: Paul Burton Cc: Leonid Yegoshin Cc: Felix Fietkau Cc: Jayachandran C. Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/13801/ Signed-off-by: Ralf Baechle

MIPS: SMP: Drop stop_this_cpu() cpu_foreign_map hack

2016-07-29T08:19:28Z

Commit cccf34e9411c ("MIPS: c-r4k: Fix cache flushing for MT cores") added the cpu_foreign_map cpumask containing a single VPE from each online core, and recalculated it when secondary CPUs are brought up. stop_this_cpu() was also updated to recalculate cpu_foreign_map, but with an additional hack before marking the CPU as offline to copy cpu_online_mask into cpu_foreign_map and perform an SMP memory barrier. This appears to have been intended to prevent cache management IPIs being missed when the VPE representing the core in cpu_foreign_map is taken offline while other VPEs remain online. Unfortunately there is nothing in this hack to prevent r4k_on_each_cpu() from reading the old cpu_foreign_map, and smp_call_function_many() from reading that new cpu_online_mask with the core's representative VPE marked offline. It then wouldn't send an IPI to any online VPEs of that core. stop_this_cpu() is only actually called in panic and system shutdown / halt / reboot situations, in which case all CPUs are going down and we don't really need to care about cache management, so drop this hack. Note that the __cpu_disable() case for CPU hotplug is handled in the previous commit, and no synchronisation is needed there due to the use of stop_machine() which prevents hotplug from taking place while any CPU has disabled preemption (as r4k_on_each_cpu() does). Signed-off-by: James Hogan Cc: Paul Burton Cc: Leonid Yegoshin Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/13796/ Signed-off-by: Ralf Baechle