Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/cmarinas/linux-aarch64

Pull ARM64 update from Catalin Marinas:
 "Main features:
   - Ticket-based spinlock implementation and lockless lockref support
   - Big endian support
   - CPU hotplug support, currently for PSCI (Power State Coordination
     Interface) capable firmware
   - Virtual address space extended to 42-bit in the 64K page
     configuration (maximum VA space with 2 levels of page tables)
   - Compat (AArch32) kuser helpers updated to ARMv8 (make use of
     load-acquire/store-release instructions)
   - Code cleanup, defconfig update and minor fixes"

* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/cmarinas/linux-aarch64: (43 commits)
  ARM64: /proc/interrupts: display IPIs of online CPUs only
  arm64: locks: Remove CONFIG_GENERIC_LOCKBREAK
  arm64: KVM: vgic: byteswap GICv2 access on world switch if BE
  arm64: KVM: initialize HYP mode following the kernel endianness
  arm64: compat: Clear the IT state independent of the 32-bit ARM or Thumb-2 mode
  arm64: Use 42-bit address space with 64K pages
  arm64: module: ensure instruction is little-endian before manipulation
  arm64: defconfig: Enable CONFIG_PREEMPT by default
  arm64: fix access to preempt_count from assembly code
  arm64: move enabling of GIC before CPUs are set online
  arm64: use generic RW_DATA_SECTION macro in linker script
  arm64: Slightly improve the warning on CPU0 enable-method
  ARM64: simplify cpu_read_bootcpu_ops using OF/DT helper
  ARM64: DT: define ARM64 specific arch_match_cpu_phys_id
  arm64: allow ioremap_cache() to use existing RAM mappings
  arm64: update 32-bit kuser helpers to ARMv8
  arm64: perf: fix event number mask
  arm64: kconfig: allow CPU_BIG_ENDIAN to be selected
  arm64: Fix the endianness of arch_spinlock_t
  arm64: big-endian: write CPU holding pen address as LE
  ...

1 files changed, 61 insertions, 0 deletions

diff --git a/arch/arm64/kernel/irq.c b/arch/arm64/kernel/irq.c
index ecb3354292ed..473e5dbf8f39 100644
--- a/arch/arm64/kernel/irq.c
+++ b/arch/arm64/kernel/irq.c
@@ -81,3 +81,64 @@ void __init init_IRQ(void)
 	if (!handle_arch_irq)
 		panic("No interrupt controller found.");
 }
+
+#ifdef CONFIG_HOTPLUG_CPU
+static bool migrate_one_irq(struct irq_desc *desc)
+{
+	struct irq_data *d = irq_desc_get_irq_data(desc);
+	const struct cpumask *affinity = d->affinity;
+	struct irq_chip *c;
+	bool ret = false;
+
+	/*
+	 * If this is a per-CPU interrupt, or the affinity does not
+	 * include this CPU, then we have nothing to do.
+	 */
+	if (irqd_is_per_cpu(d) || !cpumask_test_cpu(smp_processor_id(), affinity))
+		return false;
+
+	if (cpumask_any_and(affinity, cpu_online_mask) >= nr_cpu_ids) {
+		affinity = cpu_online_mask;
+		ret = true;
+	}
+
+	c = irq_data_get_irq_chip(d);
+	if (!c->irq_set_affinity)
+		pr_debug("IRQ%u: unable to set affinity\n", d->irq);
+	else if (c->irq_set_affinity(d, affinity, true) == IRQ_SET_MASK_OK && ret)
+		cpumask_copy(d->affinity, affinity);
+
+	return ret;
+}
+
+/*
+ * The current CPU has been marked offline.  Migrate IRQs off this CPU.
+ * If the affinity settings do not allow other CPUs, force them onto any
+ * available CPU.
+ *
+ * Note: we must iterate over all IRQs, whether they have an attached
+ * action structure or not, as we need to get chained interrupts too.
+ */
+void migrate_irqs(void)
+{
+	unsigned int i;
+	struct irq_desc *desc;
+	unsigned long flags;
+
+	local_irq_save(flags);
+
+	for_each_irq_desc(i, desc) {
+		bool affinity_broken;
+
+		raw_spin_lock(&desc->lock);
+		affinity_broken = migrate_one_irq(desc);
+		raw_spin_unlock(&desc->lock);
+
+		if (affinity_broken)
+			pr_warn_ratelimited("IRQ%u no longer affine to CPU%u\n",
+					    i, smp_processor_id());
+	}
+
+	local_irq_restore(flags);
+}
+#endif /* CONFIG_HOTPLUG_CPU */