powerpc/mm: Add HW threads support to no_hash TLB management

The current "no hash" MMU context management code is written with
the assumption that one CPU == one TLB. This is not the case on
implementations that support HW multithreading, where several
linux CPUs can share the same TLB.

This adds some basic support for this to our context management
and our TLB flushing code.

It also cleans up the optional debugging output a bit

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 8 insertions, 2 deletions

diff --git a/arch/powerpc/mm/tlb_nohash.c b/arch/powerpc/mm/tlb_nohash.c
index ad2eb4d34dd..d908e75cc3b 100644
--- a/arch/powerpc/mm/tlb_nohash.c
+++ b/arch/powerpc/mm/tlb_nohash.c
@@ -87,6 +87,12 @@ EXPORT_SYMBOL(local_flush_tlb_page);
 
 static DEFINE_SPINLOCK(tlbivax_lock);
 
+static int mm_is_core_local(struct mm_struct *mm)
+{
+        return cpumask_subset(mm_cpumask(mm),
+                              topology_thread_cpumask(smp_processor_id()));
+}
+
 struct tlb_flush_param {
         unsigned long addr;
         unsigned int pid;
@@ -131,7 +137,7 @@ void flush_tlb_mm(struct mm_struct *mm)
         pid = mm->context.id;
         if (unlikely(pid == MMU_NO_CONTEXT))
                 goto no_context;
-        if (!cpumask_equal(mm_cpumask(mm), cpumask_of(smp_processor_id()))) {
+        if (!mm_is_core_local(mm)) {
                 struct tlb_flush_param p = { .pid = pid };
                 /* Ignores smp_processor_id() even if set. */
                 smp_call_function_many(mm_cpumask(mm),
@@ -153,7 +159,7 @@ void flush_tlb_page(struct vm_area_struct *vma, unsigned long vmaddr)
         if (unlikely(pid == MMU_NO_CONTEXT))
                 goto bail;
         cpu_mask = mm_cpumask(vma->vm_mm);
-        if (!cpumask_equal(cpu_mask, cpumask_of(smp_processor_id()))) {
+        if (!mm_is_core_local(mm)) {
                 /* If broadcast tlbivax is supported, use it */
                 if (mmu_has_feature(MMU_FTR_USE_TLBIVAX_BCAST)) {
                         int lock = mmu_has_feature(MMU_FTR_LOCK_BCAST_INVAL);