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 <[e-mail]>

arch/xtensa/include/asm/tlbflush.h

···
 		unsigned long page);
 void local_flush_tlb_range(struct vm_area_struct *vma,
 		unsigned long start, unsigned long end);
+void local_flush_tlb_kernel_range(unsigned long start, unsigned long end);
 
 #ifdef CONFIG_SMP
 
···
 void flush_tlb_page(struct vm_area_struct *, unsigned long);
 void flush_tlb_range(struct vm_area_struct *, unsigned long,
 		unsigned long);
-
-static inline void flush_tlb_kernel_range(unsigned long start,
-		unsigned long end)
-{
-	flush_tlb_all();
-}
+void flush_tlb_kernel_range(unsigned long start, unsigned long end);
 
 #else /* !CONFIG_SMP */
 
···
 #define flush_tlb_page(vma, page)	   local_flush_tlb_page(vma, page)
 #define flush_tlb_range(vma, vmaddr, end)  local_flush_tlb_range(vma, vmaddr, \
 								 end)
-#define flush_tlb_kernel_range(start, end) local_flush_tlb_all()
+#define flush_tlb_kernel_range(start, end) local_flush_tlb_kernel_range(start, \
+									end)
 
 #endif /* CONFIG_SMP */
 

arch/xtensa/kernel/smp.c

···
 	on_each_cpu(ipi_flush_tlb_range, &fd, 1);
 }
 
+static void ipi_flush_tlb_kernel_range(void *arg)
+{
+	struct flush_data *fd = arg;
+	local_flush_tlb_kernel_range(fd->addr1, fd->addr2);
+}
+
+void flush_tlb_kernel_range(unsigned long start, unsigned long end)
+{
+	struct flush_data fd = {
+		.addr1 = start,
+		.addr2 = end,
+	};
+	on_each_cpu(ipi_flush_tlb_kernel_range, &fd, 1);
+}
+
 /* Cache flush functions */
 
 static void ipi_flush_cache_all(void *arg)

arch/xtensa/mm/tlb.c

···
 	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)