nds32: Correct flush_dcache_page function

1. Disable local irq before d-cache write-back and invalidate.
   The cpu_dcache_wbinval_page function is composed of d-cache
write-back and invalidate. If the local irq is enabled when calling
cpu_dcache_wbinval_page, the content of d-cache is possibly updated
between write-back and invalidate. In this case, the updated data will
be dropped due to the following d-cache invalidation. Therefore, we
disable the local irq before calling cpu_dcache_wbinval_page.

2. Correct the data write-back for page aliasing case.
   Only the page whose (page->index << PAGE_SHIFT) is located at the
same page color as page_address(page) needs to execute data write-back
in flush_dcache_page function.

Signed-off-by: Vincent Chen <vincentc@andestech.com>
Reviewed-by: Greentime Hu <greentime@andestech.com>
Signed-off-by: Greentime Hu <greentime@andestech.com>

1 files changed, 12 insertions, 9 deletions

diff --git a/arch/nds32/mm/cacheflush.c b/arch/nds32/mm/cacheflush.c
index ee44ad96b6ed..02f25ee39c1d 100644
--- a/arch/nds32/mm/cacheflush.c
+++ b/arch/nds32/mm/cacheflush.c
@@ -217,17 +217,20 @@ void flush_dcache_page(struct page *page)
         if (mapping && !mapping_mapped(mapping))
                 set_bit(PG_dcache_dirty, &page->flags);
         else {
-                int i, pc;
-                unsigned long vto, kaddr, flags;
+                unsigned long kaddr, flags;
+
                 kaddr = (unsigned long)page_address(page);
-                cpu_dcache_wbinval_page(kaddr);
-                pc = CACHE_SET(DCACHE) * CACHE_LINE_SIZE(DCACHE) / PAGE_SIZE;
                 local_irq_save(flags);
-                for (i = 0; i < pc; i++) {
-                        vto =
-                            kremap0(kaddr + i * PAGE_SIZE, page_to_phys(page));
-                        cpu_dcache_wbinval_page(vto);
-                        kunmap01(vto);
+                cpu_dcache_wbinval_page(kaddr);
+                if (mapping) {
+                        unsigned long vaddr, kto;
+
+                        vaddr = page->index << PAGE_SHIFT;
+                        if (aliasing(vaddr, kaddr)) {
+                                kto = kremap0(vaddr, page_to_phys(page));
+                                cpu_dcache_wbinval_page(kto);
+                                kunmap01(kto);
+                        }
                 }
                 local_irq_restore(flags);
         }