MIPS: cache: Provide cache flush operations for XFS

Until now flush_kernel_vmap_range() and invalidate_kernel_vmap_range() did
not exist on MIPS resulting in heavy cache corruption on XFS filesystems.

Left for the post-3.0 time: optimization and make this work with highmem,
too.  Since the combination of highmem + cache aliases atm doesn't work
this isn't a regression.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Patchwork: https://patchwork.linux-mips.org/patch/2505/
diff --git a/arch/mips/mm/c-octeon.c b/arch/mips/mm/c-octeon.c
index 16c4d256..daa81f7 100644
--- a/arch/mips/mm/c-octeon.c
+++ b/arch/mips/mm/c-octeon.c
@@ -169,6 +169,10 @@
 		octeon_flush_icache_all_cores(vma);
 }
 
+static void octeon_flush_kernel_vmap_range(unsigned long vaddr, int size)
+{
+	BUG();
+}
 
 /**
  * Probe Octeon's caches
@@ -273,6 +277,8 @@
 	flush_icache_range		= octeon_flush_icache_range;
 	local_flush_icache_range	= local_octeon_flush_icache_range;
 
+	__flush_kernel_vmap_range	= octeon_flush_kernel_vmap_range;
+
 	build_clear_page();
 	build_copy_page();
 }