1 files changed, 41 insertions, 18 deletions

diff --git a/arch/s390/lib/uaccess_pt.c b/arch/s390/lib/uaccess_pt.c
index 5efdfe9f5e76..d66215b0fde9 100644
--- a/arch/s390/lib/uaccess_pt.c
+++ b/arch/s390/lib/uaccess_pt.c
@@ -302,6 +302,10 @@ static size_t copy_in_user_pt(size_t n, void __user *to,
         pte_t *pte_from, *pte_to;
         int write_user;
 
+        if (segment_eq(get_fs(), KERNEL_DS)) {
+                memcpy((void __force *) to, (void __force *) from, n);
+                return 0;
+        }
         done = 0;
 retry:
         spin_lock(&mm->page_table_lock);
@@ -361,18 +365,10 @@ fault:
                      : "0" (-EFAULT), "d" (oparg), "a" (uaddr),         \
                        "m" (*uaddr) : "cc" );
 
-int futex_atomic_op_pt(int op, int __user *uaddr, int oparg, int *old)
+static int __futex_atomic_op_pt(int op, int __user *uaddr, int oparg, int *old)
 {
         int oldval = 0, newval, ret;
 
-        spin_lock(&current->mm->page_table_lock);
-        uaddr = (int __user *) __dat_user_addr((unsigned long) uaddr);
-        if (!uaddr) {
-                spin_unlock(&current->mm->page_table_lock);
-                return -EFAULT;
-        }
-        get_page(virt_to_page(uaddr));
-        spin_unlock(&current->mm->page_table_lock);
         switch (op) {
         case FUTEX_OP_SET:
                 __futex_atomic_op("lr %2,%5\n",
@@ -397,17 +393,17 @@ int futex_atomic_op_pt(int op, int __user *uaddr, int oparg, int *old)
         default:
                 ret = -ENOSYS;
         }
-        put_page(virt_to_page(uaddr));
-        *old = oldval;
+        if (ret == 0)
+                *old = oldval;
         return ret;
 }
 
-int futex_atomic_cmpxchg_pt(int __user *uaddr, int oldval, int newval)
+int futex_atomic_op_pt(int op, int __user *uaddr, int oparg, int *old)
 {
         int ret;
 
-        if (!current->mm)
-                return -EFAULT;
+        if (segment_eq(get_fs(), KERNEL_DS))
+                return __futex_atomic_op_pt(op, uaddr, oparg, old);
         spin_lock(&current->mm->page_table_lock);
         uaddr = (int __user *) __dat_user_addr((unsigned long) uaddr);
         if (!uaddr) {
@@ -416,13 +412,40 @@ int futex_atomic_cmpxchg_pt(int __user *uaddr, int oldval, int newval)
         }
         get_page(virt_to_page(uaddr));
         spin_unlock(&current->mm->page_table_lock);
-        asm volatile("   cs   %1,%4,0(%5)\n"
-                     "0: lr   %0,%1\n"
-                     "1:\n"
-                     EX_TABLE(0b,1b)
+        ret = __futex_atomic_op_pt(op, uaddr, oparg, old);
+        put_page(virt_to_page(uaddr));
+        return ret;
+}
+
+static int __futex_atomic_cmpxchg_pt(int __user *uaddr, int oldval, int newval)
+{
+        int ret;
+
+        asm volatile("0: cs   %1,%4,0(%5)\n"
+                     "1: lr   %0,%1\n"
+                     "2:\n"
+                     EX_TABLE(0b,2b) EX_TABLE(1b,2b)
                      : "=d" (ret), "+d" (oldval), "=m" (*uaddr)
                      : "0" (-EFAULT), "d" (newval), "a" (uaddr), "m" (*uaddr)
                      : "cc", "memory" );
+        return ret;
+}
+
+int futex_atomic_cmpxchg_pt(int __user *uaddr, int oldval, int newval)
+{
+        int ret;
+
+        if (segment_eq(get_fs(), KERNEL_DS))
+                return __futex_atomic_cmpxchg_pt(uaddr, oldval, newval);
+        spin_lock(&current->mm->page_table_lock);
+        uaddr = (int __user *) __dat_user_addr((unsigned long) uaddr);
+        if (!uaddr) {
+                spin_unlock(&current->mm->page_table_lock);
+                return -EFAULT;
+        }
+        get_page(virt_to_page(uaddr));
+        spin_unlock(&current->mm->page_table_lock);
+        ret = __futex_atomic_cmpxchg_pt(uaddr, oldval, newval);
         put_page(virt_to_page(uaddr));
         return ret;
 }