ARM: 7769/1: Cortex-A15: fix erratum 798181 implementation
Looking into the active_asids array is not enough, as we also need
to look into the reserved_asids array (they both represent processes
that are currently running).
Also, not holding the ASID allocator lock is racy, as another CPU
could schedule that process and trigger a rollover, making the erratum
workaround miss an IPI.
Exposing this outside of context.c is a little ugly on the side, so
let's define a new entry point that the erratum workaround can call
to obtain the cpumask.
Cc: <stable@vger.kernel.org> # 3.9
Acked-by: Will Deacon <will.deacon@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/mm/context.c b/arch/arm/mm/context.c
index 83e0905..eeab06e 100644
--- a/arch/arm/mm/context.c
+++ b/arch/arm/mm/context.c
@@ -45,10 +45,37 @@
static atomic64_t asid_generation = ATOMIC64_INIT(ASID_FIRST_VERSION);
static DECLARE_BITMAP(asid_map, NUM_USER_ASIDS);
-DEFINE_PER_CPU(atomic64_t, active_asids);
+static DEFINE_PER_CPU(atomic64_t, active_asids);
static DEFINE_PER_CPU(u64, reserved_asids);
static cpumask_t tlb_flush_pending;
+#ifdef CONFIG_ARM_ERRATA_798181
+void a15_erratum_get_cpumask(int this_cpu, struct mm_struct *mm,
+ cpumask_t *mask)
+{
+ int cpu;
+ unsigned long flags;
+ u64 context_id, asid;
+
+ raw_spin_lock_irqsave(&cpu_asid_lock, flags);
+ context_id = mm->context.id.counter;
+ for_each_online_cpu(cpu) {
+ if (cpu == this_cpu)
+ continue;
+ /*
+ * We only need to send an IPI if the other CPUs are
+ * running the same ASID as the one being invalidated.
+ */
+ asid = per_cpu(active_asids, cpu).counter;
+ if (asid == 0)
+ asid = per_cpu(reserved_asids, cpu);
+ if (context_id == asid)
+ cpumask_set_cpu(cpu, mask);
+ }
+ raw_spin_unlock_irqrestore(&cpu_asid_lock, flags);
+}
+#endif
+
#ifdef CONFIG_ARM_LPAE
static void cpu_set_reserved_ttbr0(void)
{