Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull leftover x86 fixes from Ingo Molnar:
 "Two leftover fixes that did not make it into v3.13"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86: Add check for number of available vectors before CPU down
  x86, cpu, amd: Add workaround for family 16h, erratum 793

1 files changed, 70 insertions, 0 deletions

diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c
index 884d875c1434..dbb60878b744 100644
--- a/arch/x86/kernel/irq.c
+++ b/arch/x86/kernel/irq.c
@@ -266,6 +266,76 @@ __visible void smp_trace_x86_platform_ipi(struct pt_regs *regs)
 EXPORT_SYMBOL_GPL(vector_used_by_percpu_irq);
 
 #ifdef CONFIG_HOTPLUG_CPU
+/*
+ * This cpu is going to be removed and its vectors migrated to the remaining
+ * online cpus.  Check to see if there are enough vectors in the remaining cpus.
+ * This function is protected by stop_machine().
+ */
+int check_irq_vectors_for_cpu_disable(void)
+{
+	int irq, cpu;
+	unsigned int this_cpu, vector, this_count, count;
+	struct irq_desc *desc;
+	struct irq_data *data;
+	struct cpumask affinity_new, online_new;
+
+	this_cpu = smp_processor_id();
+	cpumask_copy(&online_new, cpu_online_mask);
+	cpu_clear(this_cpu, online_new);
+
+	this_count = 0;
+	for (vector = FIRST_EXTERNAL_VECTOR; vector < NR_VECTORS; vector++) {
+		irq = __this_cpu_read(vector_irq[vector]);
+		if (irq >= 0) {
+			desc = irq_to_desc(irq);
+			data = irq_desc_get_irq_data(desc);
+			cpumask_copy(&affinity_new, data->affinity);
+			cpu_clear(this_cpu, affinity_new);
+
+			/* Do not count inactive or per-cpu irqs. */
+			if (!irq_has_action(irq) || irqd_is_per_cpu(data))
+				continue;
+
+			/*
+			 * A single irq may be mapped to multiple
+			 * cpu's vector_irq[] (for example IOAPIC cluster
+			 * mode).  In this case we have two
+			 * possibilities:
+			 *
+			 * 1) the resulting affinity mask is empty; that is
+			 * this the down'd cpu is the last cpu in the irq's
+			 * affinity mask, or
+			 *
+			 * 2) the resulting affinity mask is no longer
+			 * a subset of the online cpus but the affinity
+			 * mask is not zero; that is the down'd cpu is the
+			 * last online cpu in a user set affinity mask.
+			 */
+			if (cpumask_empty(&affinity_new) ||
+			    !cpumask_subset(&affinity_new, &online_new))
+				this_count++;
+		}
+	}
+
+	count = 0;
+	for_each_online_cpu(cpu) {
+		if (cpu == this_cpu)
+			continue;
+		for (vector = FIRST_EXTERNAL_VECTOR; vector < NR_VECTORS;
+		     vector++) {
+			if (per_cpu(vector_irq, cpu)[vector] < 0)
+				count++;
+		}
+	}
+
+	if (count < this_count) {
+		pr_warn("CPU %d disable failed: CPU has %u vectors assigned and there are only %u available.\n",
+			this_cpu, this_count, count);
+		return -ERANGE;
+	}
+	return 0;
+}
+
 /* A cpu has been removed from cpu_online_mask.  Reset irq affinities. */
 void fixup_irqs(void)
 {