[SPARC64]: Fix D-cache corruption in mremap

If we move a mapping from one virtual address to another,
and this changes the virtual color of the mapping to those
pages, we can see corrupt data due to D-cache aliasing.

Check for and deal with this by overriding the move_pte()
macro.  Set things up so that other platforms can cleanly
override the move_pte() macro too.

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 9 insertions, 1 deletions

diff --git a/include/asm-mips/pgtable.h b/include/asm-mips/pgtable.h
index 702a28fa7a34..69cebbd9f3e0 100644
--- a/include/asm-mips/pgtable.h
+++ b/include/asm-mips/pgtable.h
@@ -70,7 +70,15 @@ extern unsigned long zero_page_mask;
 #define ZERO_PAGE(vaddr) \
         (virt_to_page(empty_zero_page + (((unsigned long)(vaddr)) & zero_page_mask)))
 
-#define __HAVE_ARCH_MULTIPLE_ZERO_PAGE
+#define __HAVE_ARCH_MOVE_PTE
+#define move_pte(pte, prot, old_addr, new_addr)                         \
+({                                                                      \
+        pte_t newpte = (pte);                                           \
+        if (pte_present(pte) && pfn_valid(pte_pfn(pte)) &&              \
+                        pte_page(pte) == ZERO_PAGE(old_addr))           \
+                newpte = mk_pte(ZERO_PAGE(new_addr), (prot));           \
+        newpte;                                                         \
+})
 
 extern void paging_init(void);