3 files changed, 48 insertions, 9 deletions

diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h
index 1709801d18ec..1e963267d44e 100644
--- a/arch/x86/include/asm/uaccess.h
+++ b/arch/x86/include/asm/uaccess.h
@@ -151,8 +151,15 @@ extern int __get_user_bad(void);
  * On error, the variable @x is set to zero.
  */
 #ifdef CONFIG_X86_32
-#define __get_user_8(__ret_gu, __val_gu, ptr)                           \
-                __get_user_x(X, __ret_gu, __val_gu, ptr)
+#define __get_user_8(ret, x, ptr)                     \
+do {                                                  \
+        register unsigned long long __xx asm("%edx"); \
+        asm volatile("call __get_user_8"              \
+                     : "=a" (ret), "=r" (__xx)        \
+                     : "0" (ptr));                    \
+        (x) = __xx;                                   \
+} while (0)
+
 #else
 #define __get_user_8(__ret_gu, __val_gu, ptr)                           \
                 __get_user_x(8, __ret_gu, __val_gu, ptr)
@@ -162,6 +169,7 @@ extern int __get_user_bad(void);
 ({                                                                      \
         int __ret_gu;                                                   \
         unsigned long __val_gu;                                         \
+        unsigned long long __val_gu8;                                   \
         __chk_user_ptr(ptr);                                            \
         might_fault();                                                  \
         switch (sizeof(*(ptr))) {                                       \
@@ -175,13 +183,16 @@ extern int __get_user_bad(void);
                 __get_user_x(4, __ret_gu, __val_gu, ptr);               \
                 break;                                                  \
         case 8:                                                         \
-                __get_user_8(__ret_gu, __val_gu, ptr);                  \
+                __get_user_8(__ret_gu, __val_gu8, ptr);                 \
                 break;                                                  \
         default:                                                        \
                 __get_user_x(X, __ret_gu, __val_gu, ptr);               \
                 break;                                                  \
         }                                                               \
-        (x) = (__typeof__(*(ptr)))__val_gu;                             \
+        if (sizeof(*(ptr)) == 8)                                        \
+                (x) = (__typeof__(*(ptr)))__val_gu8;                    \
+        else                                                            \
+                (x) = (__typeof__(*(ptr)))__val_gu;                     \
         __ret_gu;                                                       \
 })
 
diff --git a/arch/x86/kernel/i386_ksyms_32.c b/arch/x86/kernel/i386_ksyms_32.c
index 9c3bd4a2050e..0fa69127209a 100644
--- a/arch/x86/kernel/i386_ksyms_32.c
+++ b/arch/x86/kernel/i386_ksyms_32.c
@@ -26,6 +26,7 @@ EXPORT_SYMBOL(csum_partial_copy_generic);
 EXPORT_SYMBOL(__get_user_1);
 EXPORT_SYMBOL(__get_user_2);
 EXPORT_SYMBOL(__get_user_4);
+EXPORT_SYMBOL(__get_user_8);
 
 EXPORT_SYMBOL(__put_user_1);
 EXPORT_SYMBOL(__put_user_2);
diff --git a/arch/x86/lib/getuser.S b/arch/x86/lib/getuser.S
index 156b9c804670..d3bf9f99ca77 100644
--- a/arch/x86/lib/getuser.S
+++ b/arch/x86/lib/getuser.S
@@ -15,11 +15,10 @@
  * __get_user_X
  *
  * Inputs:      %[r|e]ax contains the address.
- *              The register is modified, but all changes are undone
- *              before returning because the C code doesn't know about it.
  *
  * Outputs:     %[r|e]ax is error code (0 or -EFAULT)
  *              %[r|e]dx contains zero-extended value
+ *              %ecx contains the high half for 32-bit __get_user_8
  *
  *
  * These functions should not modify any other registers,
@@ -79,22 +78,35 @@ ENTRY(__get_user_4)
         CFI_ENDPROC
 ENDPROC(__get_user_4)
 
-#ifdef CONFIG_X86_64
 ENTRY(__get_user_8)
         CFI_STARTPROC
+#ifdef CONFIG_X86_64
         add $7,%_ASM_AX
         jc bad_get_user
         GET_THREAD_INFO(%_ASM_DX)
         cmp TI_addr_limit(%_ASM_DX),%_ASM_AX
-        jae     bad_get_user
+        jae bad_get_user
         ASM_STAC
 4:      movq -7(%_ASM_AX),%_ASM_DX
         xor %eax,%eax
         ASM_CLAC
         ret
+#else
+        add $7,%_ASM_AX
+        jc bad_get_user_8
+        GET_THREAD_INFO(%_ASM_DX)
+        cmp TI_addr_limit(%_ASM_DX),%_ASM_AX
+        jae bad_get_user_8
+        ASM_STAC
+4:      mov -7(%_ASM_AX),%edx
+5:      mov -3(%_ASM_AX),%ecx
+        xor %eax,%eax
+        ASM_CLAC
+        ret
+#endif
         CFI_ENDPROC
 ENDPROC(__get_user_8)
-#endif
+
 
 bad_get_user:
         CFI_STARTPROC
@@ -105,9 +117,24 @@ bad_get_user:
         CFI_ENDPROC
 END(bad_get_user)
 
+#ifdef CONFIG_X86_32
+bad_get_user_8:
+        CFI_STARTPROC
+        xor %edx,%edx
+        xor %ecx,%ecx
+        mov $(-EFAULT),%_ASM_AX
+        ASM_CLAC
+        ret
+        CFI_ENDPROC
+END(bad_get_user_8)
+#endif
+
         _ASM_EXTABLE(1b,bad_get_user)
         _ASM_EXTABLE(2b,bad_get_user)
         _ASM_EXTABLE(3b,bad_get_user)
 #ifdef CONFIG_X86_64
         _ASM_EXTABLE(4b,bad_get_user)
+#else
+        _ASM_EXTABLE(4b,bad_get_user_8)
+        _ASM_EXTABLE(5b,bad_get_user_8)
 #endif