2 files changed, 32 insertions, 6 deletions

diff --git a/arch/x86/include/asm/xen/page.h b/arch/x86/include/asm/xen/page.h
index 123e669bf363..790ce08e41f2 100644
--- a/arch/x86/include/asm/xen/page.h
+++ b/arch/x86/include/asm/xen/page.h
@@ -9,7 +9,7 @@
 #include <linux/mm.h>
 #include <linux/device.h>
 
-#include <linux/uaccess.h>
+#include <asm/extable.h>
 #include <asm/page.h>
 #include <asm/pgtable.h>
 
@@ -93,12 +93,39 @@ clear_foreign_p2m_mapping(struct gnttab_unmap_grant_ref *unmap_ops,
  */
 static inline int xen_safe_write_ulong(unsigned long *addr, unsigned long val)
 {
-        return __put_user(val, (unsigned long __user *)addr);
+        int ret = 0;
+
+        asm volatile("1: mov %[val], %[ptr]\n"
+                     "2:\n"
+                     ".section .fixup, \"ax\"\n"
+                     "3: sub $1, %[ret]\n"
+                     "   jmp 2b\n"
+                     ".previous\n"
+                     _ASM_EXTABLE(1b, 3b)
+                     : [ret] "+r" (ret), [ptr] "=m" (*addr)
+                     : [val] "r" (val));
+
+        return ret;
 }
 
-static inline int xen_safe_read_ulong(unsigned long *addr, unsigned long *val)
+static inline int xen_safe_read_ulong(const unsigned long *addr,
+                                      unsigned long *val)
 {
-        return __get_user(*val, (unsigned long __user *)addr);
+        int ret = 0;
+        unsigned long rval = ~0ul;
+
+        asm volatile("1: mov %[ptr], %[rval]\n"
+                     "2:\n"
+                     ".section .fixup, \"ax\"\n"
+                     "3: sub $1, %[ret]\n"
+                     "   jmp 2b\n"
+                     ".previous\n"
+                     _ASM_EXTABLE(1b, 3b)
+                     : [ret] "+r" (ret), [rval] "+r" (rval)
+                     : [ptr] "m" (*addr));
+        *val = rval;
+
+        return ret;
 }
 
 #ifdef CONFIG_XEN_PV
diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c
index d6d74efd8912..4fe84436d5a7 100644
--- a/arch/x86/xen/p2m.c
+++ b/arch/x86/xen/p2m.c
@@ -656,8 +656,7 @@ bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn)
 
         /*
          * The interface requires atomic updates on p2m elements.
-         * xen_safe_write_ulong() is using __put_user which does an atomic
-         * store via asm().
+         * xen_safe_write_ulong() is using an atomic store via asm().
          */
         if (likely(!xen_safe_write_ulong(xen_p2m_addr + pfn, mfn)))
                 return true;