xtensa: optimize local_flush_tlb_kernel_range

Don't flush whole TLB if only a small kernel range is requested.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

arch/xtensa/mm/tlb.c

@@ -149,6 +149,21 @@ void local_flush_tlb_page(struct vm_area_struct *vma, unsigned long page)
 	local_irq_restore(flags);
 }
 
+void local_flush_tlb_kernel_range(unsigned long start, unsigned long end)
+{
+	if (end > start && start >= TASK_SIZE && end <= PAGE_OFFSET &&
+	    end - start < _TLB_ENTRIES << PAGE_SHIFT) {
+		start &= PAGE_MASK;
+		while (start < end) {
+			invalidate_itlb_mapping(start);
+			invalidate_dtlb_mapping(start);
+			start += PAGE_SIZE;
+		}
+	} else {
+		local_flush_tlb_all();
+	}
+}
+
 #ifdef CONFIG_DEBUG_TLB_SANITY
 
 static unsigned get_pte_for_vaddr(unsigned vaddr)