ARC: lazy dcache flush broke gdb in non-aliasing configs

gdbserver inserting a breakpoint ends up calling copy_user_page() for a
code page. The generic version of which (non-aliasing config) didn't set
the PG_arch_1 bit hence update_mmu_cache() didn't sync dcache/icache for
corresponding dynamic loader code page - causing garbade to be executed.

So now aliasing versions of copy_user_highpage()/clear_page() are made
default. There is no significant overhead since all of special alias
handling code is compiled out for non-aliasing build

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>

1 files changed, 11 insertions, 10 deletions

diff --git a/arch/arc/mm/cache_arc700.c b/arch/arc/mm/cache_arc700.c
index d4b7bb616840..aedce1905441 100644
--- a/arch/arc/mm/cache_arc700.c
+++ b/arch/arc/mm/cache_arc700.c
@@ -676,6 +676,17 @@ void flush_cache_range(struct vm_area_struct *vma, unsigned long start,
         flush_cache_all();
 }
 
+void flush_anon_page(struct vm_area_struct *vma, struct page *page,
+                     unsigned long u_vaddr)
+{
+        /* TBD: do we really need to clear the kernel mapping */
+        __flush_dcache_page(page_address(page), u_vaddr);
+        __flush_dcache_page(page_address(page), page_address(page));
+
+}
+
+#endif
+
 void copy_user_highpage(struct page *to, struct page *from,
         unsigned long u_vaddr, struct vm_area_struct *vma)
 {
@@ -725,16 +736,6 @@ void clear_user_page(void *to, unsigned long u_vaddr, struct page *page)
         set_bit(PG_arch_1, &page->flags);
 }
 
-void flush_anon_page(struct vm_area_struct *vma, struct page *page,
-                     unsigned long u_vaddr)
-{
-        /* TBD: do we really need to clear the kernel mapping */
-        __flush_dcache_page(page_address(page), u_vaddr);
-        __flush_dcache_page(page_address(page), page_address(page));
-
-}
-
-#endif
 
 /**********************************************************************
  * Explicit Cache flush request from user space via syscall