1 files changed, 16 insertions, 22 deletions

diff --git a/arch/s390/mm/maccess.c b/arch/s390/mm/maccess.c
index 795a0a9bb2eb..921fa541dc04 100644
--- a/arch/s390/mm/maccess.c
+++ b/arch/s390/mm/maccess.c
@@ -101,19 +101,27 @@ int memcpy_real(void *dest, void *src, size_t count)
 }
 
 /*
- * Copy memory to absolute zero
+ * Copy memory in absolute mode (kernel to kernel)
  */
-void copy_to_absolute_zero(void *dest, void *src, size_t count)
+void memcpy_absolute(void *dest, void *src, size_t count)
 {
-        unsigned long cr0;
+        unsigned long cr0, flags, prefix;
 
-        BUG_ON((unsigned long) dest + count >= sizeof(struct _lowcore));
-        preempt_disable();
+        flags = arch_local_irq_save();
         __ctl_store(cr0, 0, 0);
         __ctl_clear_bit(0, 28); /* disable lowcore protection */
-        memcpy_real(dest + store_prefix(), src, count);
+        prefix = store_prefix();
+        if (prefix) {
+                local_mcck_disable();
+                set_prefix(0);
+                memcpy(dest, src, count);
+                set_prefix(prefix);
+                local_mcck_enable();
+        } else {
+                memcpy(dest, src, count);
+        }
         __ctl_load(cr0, 0, 0);
-        preempt_enable();
+        arch_local_irq_restore(flags);
 }
 
 /*
@@ -188,20 +196,6 @@ static int is_swapped(unsigned long addr)
 }
 
 /*
- * Return swapped prefix or zero page address
- */
-static unsigned long get_swapped(unsigned long addr)
-{
-        unsigned long prefix = store_prefix();
-
-        if (addr < sizeof(struct _lowcore))
-                return addr + prefix;
-        if (addr >= prefix && addr < prefix + sizeof(struct _lowcore))
-                return addr - prefix;
-        return addr;
-}
-
-/*
  * Convert a physical pointer for /dev/mem access
  *
  * For swapped prefix pages a new buffer is returned that contains a copy of
@@ -218,7 +212,7 @@ void *xlate_dev_mem_ptr(unsigned long addr)
                 size = PAGE_SIZE - (addr & ~PAGE_MASK);
                 bounce = (void *) __get_free_page(GFP_ATOMIC);
                 if (bounce)
-                        memcpy_real(bounce, (void *) get_swapped(addr), size);
+                        memcpy_absolute(bounce, (void *) addr, size);
         }
         preempt_enable();
         put_online_cpus();