1 files changed, 23 insertions, 3 deletions

diff --git a/arch/mn10300/mm/init.c b/arch/mn10300/mm/init.c
index 6e6bc0e51521..48907cc3bdb7 100644
--- a/arch/mn10300/mm/init.c
+++ b/arch/mn10300/mm/init.c
@@ -41,6 +41,10 @@ DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
 
 unsigned long highstart_pfn, highend_pfn;
 
+#ifdef CONFIG_MN10300_HAS_ATOMIC_OPS_UNIT
+static struct vm_struct user_iomap_vm;
+#endif
+
 /*
  * set up paging
  */
@@ -73,7 +77,24 @@ void __init paging_init(void)
         /* pass the memory from the bootmem allocator to the main allocator */
         free_area_init(zones_size);
 
-        __flush_tlb_all();
+#ifdef CONFIG_MN10300_HAS_ATOMIC_OPS_UNIT
+        /* The Atomic Operation Unit registers need to be mapped to userspace
+         * for all processes.  The following uses vm_area_register_early() to
+         * reserve the first page of the vmalloc area and sets the pte for that
+         * page.
+         *
+         * glibc hardcodes this virtual mapping, so we're pretty much stuck with
+         * it from now on.
+         */
+        user_iomap_vm.flags = VM_USERMAP;
+        user_iomap_vm.size = 1 << PAGE_SHIFT;
+        vm_area_register_early(&user_iomap_vm, PAGE_SIZE);
+        ppte = kernel_vmalloc_ptes;
+        set_pte(ppte, pfn_pte(USER_ATOMIC_OPS_PAGE_ADDR >> PAGE_SHIFT,
+                              PAGE_USERIO));
+#endif
+
+        local_flush_tlb_all();
 }
 
 /*
@@ -84,8 +105,7 @@ void __init mem_init(void)
         int codesize, reservedpages, datasize, initsize;
         int tmp;
 
-        if (!mem_map)
-                BUG();
+        BUG_ON(!mem_map);
 
 #define START_PFN       (contig_page_data.bdata->node_min_pfn)
 #define MAX_LOW_PFN     (contig_page_data.bdata->node_low_pfn)