2 files changed, 24 insertions, 0 deletions

diff --git a/arch/mn10300/include/asm/pgtable.h b/arch/mn10300/include/asm/pgtable.h
index cd568bf5407e..a1e894b5f65b 100644
--- a/arch/mn10300/include/asm/pgtable.h
+++ b/arch/mn10300/include/asm/pgtable.h
@@ -182,6 +182,9 @@ extern pte_t kernel_vmalloc_ptes[(VMALLOC_END - VMALLOC_START) / PAGE_SIZE];
 #define PAGE_KERNEL_LARGE       __pgprot(__PAGE_KERNEL_LARGE)
 #define PAGE_KERNEL_LARGE_EXEC  __pgprot(__PAGE_KERNEL_LARGE_EXEC)
 
+#define __PAGE_USERIO           (__PAGE_KERNEL_BASE | _PAGE_PROT_WKWU | _PAGE_NX)
+#define PAGE_USERIO             __pgprot(__PAGE_USERIO)
+
 /*
  * Whilst the MN10300 can do page protection for execute (given separate data
  * and insn TLBs), we are not supporting it at the moment. Write permission,
diff --git a/arch/mn10300/mm/init.c b/arch/mn10300/mm/init.c
index 1daf97fd7c99..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
  */
@@ -73,6 +77,23 @@ void __init paging_init(void)
         /* pass the memory from the bootmem allocator to the main allocator */
         free_area_init(zones_size);
 
+#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();
 }